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WIP FPC-III support
[linux/fpc-iii.git] / drivers / tty / serial / 8250 / 8250_port.c
blobb0af13074cd36d877ee7f1177af8cbc1ff07eab6
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Base port operations for 8250/16550-type serial ports
4 *
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6 * Split from 8250_core.c, Copyright (C) 2001 Russell King.
7 *
8 * A note about mapbase / membase
9 *
10 * mapbase is the physical address of the IO port.
11 * membase is an 'ioremapped' cookie.
12 */
13
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/ioport.h>
17 #include <linux/init.h>
18 #include <linux/console.h>
19 #include <linux/gpio/consumer.h>
20 #include <linux/sysrq.h>
21 #include <linux/delay.h>
22 #include <linux/platform_device.h>
23 #include <linux/tty.h>
24 #include <linux/ratelimit.h>
25 #include <linux/tty_flip.h>
26 #include <linux/serial.h>
27 #include <linux/serial_8250.h>
28 #include <linux/nmi.h>
29 #include <linux/mutex.h>
30 #include <linux/slab.h>
31 #include <linux/uaccess.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/ktime.h>
34
35 #include <asm/io.h>
36 #include <asm/irq.h>
37
38 #include "8250.h"
39
40 /* Nuvoton NPCM timeout register */
41 #define UART_NPCM_TOR 7
42 #define UART_NPCM_TOIE BIT(7) /* Timeout Interrupt Enable */
43
44 /*
45 * Debugging.
46 */
47 #if 0
48 #define DEBUG_AUTOCONF(fmt...) printk(fmt)
49 #else
50 #define DEBUG_AUTOCONF(fmt...) do { } while (0)
51 #endif
52
53 #define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)
54
55 /*
56 * Here we define the default xmit fifo size used for each type of UART.
57 */
58 static const struct serial8250_config uart_config[] = {
59 [PORT_UNKNOWN] = {
60 .name = "unknown",
61 .fifo_size = 1,
62 .tx_loadsz = 1,
63 },
64 [PORT_8250] = {
65 .name = "8250",
66 .fifo_size = 1,
67 .tx_loadsz = 1,
68 },
69 [PORT_16450] = {
70 .name = "16450",
71 .fifo_size = 1,
72 .tx_loadsz = 1,
73 },
74 [PORT_16550] = {
75 .name = "16550",
76 .fifo_size = 1,
77 .tx_loadsz = 1,
78 },
79 [PORT_16550A] = {
80 .name = "16550A",
81 .fifo_size = 16,
82 .tx_loadsz = 16,
83 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
84 .rxtrig_bytes = {1, 4, 8, 14},
85 .flags = UART_CAP_FIFO,
86 },
87 [PORT_CIRRUS] = {
88 .name = "Cirrus",
89 .fifo_size = 1,
90 .tx_loadsz = 1,
91 },
92 [PORT_16650] = {
93 .name = "ST16650",
94 .fifo_size = 1,
95 .tx_loadsz = 1,
96 .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
97 },
98 [PORT_16650V2] = {
99 .name = "ST16650V2",
100 .fifo_size = 32,
101 .tx_loadsz = 16,
102 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
103 UART_FCR_T_TRIG_00,
104 .rxtrig_bytes = {8, 16, 24, 28},
105 .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
106 },
107 [PORT_16750] = {
108 .name = "TI16750",
109 .fifo_size = 64,
110 .tx_loadsz = 64,
111 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
112 UART_FCR7_64BYTE,
113 .rxtrig_bytes = {1, 16, 32, 56},
114 .flags = UART_CAP_FIFO | UART_CAP_SLEEP | UART_CAP_AFE,
115 },
116 [PORT_STARTECH] = {
117 .name = "Startech",
118 .fifo_size = 1,
119 .tx_loadsz = 1,
120 },
121 [PORT_16C950] = {
122 .name = "16C950/954",
123 .fifo_size = 128,
124 .tx_loadsz = 128,
125 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
126 /* UART_CAP_EFR breaks billionon CF bluetooth card. */
127 .flags = UART_CAP_FIFO | UART_CAP_SLEEP,
128 },
129 [PORT_16654] = {
130 .name = "ST16654",
131 .fifo_size = 64,
132 .tx_loadsz = 32,
133 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
134 UART_FCR_T_TRIG_10,
135 .rxtrig_bytes = {8, 16, 56, 60},
136 .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
137 },
138 [PORT_16850] = {
139 .name = "XR16850",
140 .fifo_size = 128,
141 .tx_loadsz = 128,
142 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
143 .flags = UART_CAP_FIFO | UART_CAP_EFR | UART_CAP_SLEEP,
144 },
145 [PORT_RSA] = {
146 .name = "RSA",
147 .fifo_size = 2048,
148 .tx_loadsz = 2048,
149 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11,
150 .flags = UART_CAP_FIFO,
151 },
152 [PORT_NS16550A] = {
153 .name = "NS16550A",
154 .fifo_size = 16,
155 .tx_loadsz = 16,
156 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
157 .flags = UART_CAP_FIFO | UART_NATSEMI,
158 },
159 [PORT_XSCALE] = {
160 .name = "XScale",
161 .fifo_size = 32,
162 .tx_loadsz = 32,
163 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
164 .flags = UART_CAP_FIFO | UART_CAP_UUE | UART_CAP_RTOIE,
165 },
166 [PORT_OCTEON] = {
167 .name = "OCTEON",
168 .fifo_size = 64,
169 .tx_loadsz = 64,
170 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
171 .flags = UART_CAP_FIFO,
172 },
173 [PORT_AR7] = {
174 .name = "AR7",
175 .fifo_size = 16,
176 .tx_loadsz = 16,
177 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
178 .flags = UART_CAP_FIFO /* | UART_CAP_AFE */,
179 },
180 [PORT_U6_16550A] = {
181 .name = "U6_16550A",
182 .fifo_size = 64,
183 .tx_loadsz = 64,
184 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
185 .flags = UART_CAP_FIFO | UART_CAP_AFE,
186 },
187 [PORT_TEGRA] = {
188 .name = "Tegra",
189 .fifo_size = 32,
190 .tx_loadsz = 8,
191 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_01 |
192 UART_FCR_T_TRIG_01,
193 .rxtrig_bytes = {1, 4, 8, 14},
194 .flags = UART_CAP_FIFO | UART_CAP_RTOIE,
195 },
196 [PORT_XR17D15X] = {
197 .name = "XR17D15X",
198 .fifo_size = 64,
199 .tx_loadsz = 64,
200 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
201 .flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
202 UART_CAP_SLEEP,
203 },
204 [PORT_XR17V35X] = {
205 .name = "XR17V35X",
206 .fifo_size = 256,
207 .tx_loadsz = 256,
208 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_11 |
209 UART_FCR_T_TRIG_11,
210 .flags = UART_CAP_FIFO | UART_CAP_AFE | UART_CAP_EFR |
211 UART_CAP_SLEEP,
212 },
213 [PORT_LPC3220] = {
214 .name = "LPC3220",
215 .fifo_size = 64,
216 .tx_loadsz = 32,
217 .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
218 UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
219 .flags = UART_CAP_FIFO,
220 },
221 [PORT_BRCM_TRUMANAGE] = {
222 .name = "TruManage",
223 .fifo_size = 1,
224 .tx_loadsz = 1024,
225 .flags = UART_CAP_HFIFO,
226 },
227 [PORT_8250_CIR] = {
228 .name = "CIR port"
229 },
230 [PORT_ALTR_16550_F32] = {
231 .name = "Altera 16550 FIFO32",
232 .fifo_size = 32,
233 .tx_loadsz = 32,
234 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
235 .rxtrig_bytes = {1, 8, 16, 30},
236 .flags = UART_CAP_FIFO | UART_CAP_AFE,
237 },
238 [PORT_ALTR_16550_F64] = {
239 .name = "Altera 16550 FIFO64",
240 .fifo_size = 64,
241 .tx_loadsz = 64,
242 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
243 .rxtrig_bytes = {1, 16, 32, 62},
244 .flags = UART_CAP_FIFO | UART_CAP_AFE,
245 },
246 [PORT_ALTR_16550_F128] = {
247 .name = "Altera 16550 FIFO128",
248 .fifo_size = 128,
249 .tx_loadsz = 128,
250 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
251 .rxtrig_bytes = {1, 32, 64, 126},
252 .flags = UART_CAP_FIFO | UART_CAP_AFE,
253 },
254 /*
255 * tx_loadsz is set to 63-bytes instead of 64-bytes to implement
256 * workaround of errata A-008006 which states that tx_loadsz should
257 * be configured less than Maximum supported fifo bytes.
258 */
259 [PORT_16550A_FSL64] = {
260 .name = "16550A_FSL64",
261 .fifo_size = 64,
262 .tx_loadsz = 63,
263 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
264 UART_FCR7_64BYTE,
265 .flags = UART_CAP_FIFO,
266 },
267 [PORT_RT2880] = {
268 .name = "Palmchip BK-3103",
269 .fifo_size = 16,
270 .tx_loadsz = 16,
271 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
272 .rxtrig_bytes = {1, 4, 8, 14},
273 .flags = UART_CAP_FIFO,
274 },
275 [PORT_DA830] = {
276 .name = "TI DA8xx/66AK2x",
277 .fifo_size = 16,
278 .tx_loadsz = 16,
279 .fcr = UART_FCR_DMA_SELECT | UART_FCR_ENABLE_FIFO |
280 UART_FCR_R_TRIG_10,
281 .rxtrig_bytes = {1, 4, 8, 14},
282 .flags = UART_CAP_FIFO | UART_CAP_AFE,
283 },
284 [PORT_MTK_BTIF] = {
285 .name = "MediaTek BTIF",
286 .fifo_size = 16,
287 .tx_loadsz = 16,
288 .fcr = UART_FCR_ENABLE_FIFO |
289 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
290 .flags = UART_CAP_FIFO,
291 },
292 [PORT_NPCM] = {
293 .name = "Nuvoton 16550",
294 .fifo_size = 16,
295 .tx_loadsz = 16,
296 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10 |
297 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT,
298 .rxtrig_bytes = {1, 4, 8, 14},
299 .flags = UART_CAP_FIFO,
300 },
301 [PORT_SUNIX] = {
302 .name = "Sunix",
303 .fifo_size = 128,
304 .tx_loadsz = 128,
305 .fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10,
306 .rxtrig_bytes = {1, 32, 64, 112},
307 .flags = UART_CAP_FIFO | UART_CAP_SLEEP,
308 },
309 };
310
311 /* Uart divisor latch read */
312 static int default_serial_dl_read(struct uart_8250_port *up)
313 {
314 return serial_in(up, UART_DLL) | serial_in(up, UART_DLM) << 8;
315 }
316
317 /* Uart divisor latch write */
318 static void default_serial_dl_write(struct uart_8250_port *up, int value)
319 {
320 serial_out(up, UART_DLL, value & 0xff);
321 serial_out(up, UART_DLM, value >> 8 & 0xff);
322 }
323
324 #ifdef CONFIG_SERIAL_8250_RT288X
325
326 /* Au1x00/RT288x UART hardware has a weird register layout */
327 static const s8 au_io_in_map[8] = {
328 0, /* UART_RX */
329 2, /* UART_IER */
330 3, /* UART_IIR */
331 5, /* UART_LCR */
332 6, /* UART_MCR */
333 7, /* UART_LSR */
334 8, /* UART_MSR */
335 -1, /* UART_SCR (unmapped) */
336 };
337
338 static const s8 au_io_out_map[8] = {
339 1, /* UART_TX */
340 2, /* UART_IER */
341 4, /* UART_FCR */
342 5, /* UART_LCR */
343 6, /* UART_MCR */
344 -1, /* UART_LSR (unmapped) */
345 -1, /* UART_MSR (unmapped) */
346 -1, /* UART_SCR (unmapped) */
347 };
348
349 unsigned int au_serial_in(struct uart_port *p, int offset)
350 {
351 if (offset >= ARRAY_SIZE(au_io_in_map))
352 return UINT_MAX;
353 offset = au_io_in_map[offset];
354 if (offset < 0)
355 return UINT_MAX;
356 return __raw_readl(p->membase + (offset << p->regshift));
357 }
358
359 void au_serial_out(struct uart_port *p, int offset, int value)
360 {
361 if (offset >= ARRAY_SIZE(au_io_out_map))
362 return;
363 offset = au_io_out_map[offset];
364 if (offset < 0)
365 return;
366 __raw_writel(value, p->membase + (offset << p->regshift));
367 }
368
369 /* Au1x00 haven't got a standard divisor latch */
370 static int au_serial_dl_read(struct uart_8250_port *up)
371 {
372 return __raw_readl(up->port.membase + 0x28);
373 }
374
375 static void au_serial_dl_write(struct uart_8250_port *up, int value)
376 {
377 __raw_writel(value, up->port.membase + 0x28);
378 }
379
380 #endif
381
382 static unsigned int hub6_serial_in(struct uart_port *p, int offset)
383 {
384 offset = offset << p->regshift;
385 outb(p->hub6 - 1 + offset, p->iobase);
386 return inb(p->iobase + 1);
387 }
388
389 static void hub6_serial_out(struct uart_port *p, int offset, int value)
390 {
391 offset = offset << p->regshift;
392 outb(p->hub6 - 1 + offset, p->iobase);
393 outb(value, p->iobase + 1);
394 }
395
396 static unsigned int mem_serial_in(struct uart_port *p, int offset)
397 {
398 offset = offset << p->regshift;
399 return readb(p->membase + offset);
400 }
401
402 static void mem_serial_out(struct uart_port *p, int offset, int value)
403 {
404 offset = offset << p->regshift;
405 writeb(value, p->membase + offset);
406 }
407
408 static void mem16_serial_out(struct uart_port *p, int offset, int value)
409 {
410 offset = offset << p->regshift;
411 writew(value, p->membase + offset);
412 }
413
414 static unsigned int mem16_serial_in(struct uart_port *p, int offset)
415 {
416 offset = offset << p->regshift;
417 return readw(p->membase + offset);
418 }
419
420 static void mem32_serial_out(struct uart_port *p, int offset, int value)
421 {
422 offset = offset << p->regshift;
423 writel(value, p->membase + offset);
424 }
425
426 static unsigned int mem32_serial_in(struct uart_port *p, int offset)
427 {
428 offset = offset << p->regshift;
429 return readl(p->membase + offset);
430 }
431
432 static void mem32be_serial_out(struct uart_port *p, int offset, int value)
433 {
434 offset = offset << p->regshift;
435 iowrite32be(value, p->membase + offset);
436 }
437
438 static unsigned int mem32be_serial_in(struct uart_port *p, int offset)
439 {
440 offset = offset << p->regshift;
441 return ioread32be(p->membase + offset);
442 }
443
444 static unsigned int io_serial_in(struct uart_port *p, int offset)
445 {
446 offset = offset << p->regshift;
447 return inb(p->iobase + offset);
448 }
449
450 static void io_serial_out(struct uart_port *p, int offset, int value)
451 {
452 offset = offset << p->regshift;
453 outb(value, p->iobase + offset);
454 }
455
456 static int serial8250_default_handle_irq(struct uart_port *port);
457
458 static void set_io_from_upio(struct uart_port *p)
459 {
460 struct uart_8250_port *up = up_to_u8250p(p);
461
462 up->dl_read = default_serial_dl_read;
463 up->dl_write = default_serial_dl_write;
464
465 switch (p->iotype) {
466 case UPIO_HUB6:
467 p->serial_in = hub6_serial_in;
468 p->serial_out = hub6_serial_out;
469 break;
470
471 case UPIO_MEM:
472 p->serial_in = mem_serial_in;
473 p->serial_out = mem_serial_out;
474 break;
475
476 case UPIO_MEM16:
477 p->serial_in = mem16_serial_in;
478 p->serial_out = mem16_serial_out;
479 break;
480
481 case UPIO_MEM32:
482 p->serial_in = mem32_serial_in;
483 p->serial_out = mem32_serial_out;
484 break;
485
486 case UPIO_MEM32BE:
487 p->serial_in = mem32be_serial_in;
488 p->serial_out = mem32be_serial_out;
489 break;
490
491 #ifdef CONFIG_SERIAL_8250_RT288X
492 case UPIO_AU:
493 p->serial_in = au_serial_in;
494 p->serial_out = au_serial_out;
495 up->dl_read = au_serial_dl_read;
496 up->dl_write = au_serial_dl_write;
497 break;
498 #endif
499
500 default:
501 p->serial_in = io_serial_in;
502 p->serial_out = io_serial_out;
503 break;
504 }
505 /* Remember loaded iotype */
506 up->cur_iotype = p->iotype;
507 p->handle_irq = serial8250_default_handle_irq;
508 }
509
510 static void
511 serial_port_out_sync(struct uart_port *p, int offset, int value)
512 {
513 switch (p->iotype) {
514 case UPIO_MEM:
515 case UPIO_MEM16:
516 case UPIO_MEM32:
517 case UPIO_MEM32BE:
518 case UPIO_AU:
519 p->serial_out(p, offset, value);
520 p->serial_in(p, UART_LCR); /* safe, no side-effects */
521 break;
522 default:
523 p->serial_out(p, offset, value);
524 }
525 }
526
527 /*
528 * For the 16C950
529 */
530 static void serial_icr_write(struct uart_8250_port *up, int offset, int value)
531 {
532 serial_out(up, UART_SCR, offset);
533 serial_out(up, UART_ICR, value);
534 }
535
536 static unsigned int serial_icr_read(struct uart_8250_port *up, int offset)
537 {
538 unsigned int value;
539
540 serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD);
541 serial_out(up, UART_SCR, offset);
542 value = serial_in(up, UART_ICR);
543 serial_icr_write(up, UART_ACR, up->acr);
544
545 return value;
546 }
547
548 /*
549 * FIFO support.
550 */
551 static void serial8250_clear_fifos(struct uart_8250_port *p)
552 {
553 if (p->capabilities & UART_CAP_FIFO) {
554 serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO);
555 serial_out(p, UART_FCR, UART_FCR_ENABLE_FIFO |
556 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
557 serial_out(p, UART_FCR, 0);
558 }
559 }
560
561 static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t);
562 static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t);
563
564 void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p)
565 {
566 serial8250_clear_fifos(p);
567 serial_out(p, UART_FCR, p->fcr);
568 }
569 EXPORT_SYMBOL_GPL(serial8250_clear_and_reinit_fifos);
570
571 void serial8250_rpm_get(struct uart_8250_port *p)
572 {
573 if (!(p->capabilities & UART_CAP_RPM))
574 return;
575 pm_runtime_get_sync(p->port.dev);
576 }
577 EXPORT_SYMBOL_GPL(serial8250_rpm_get);
578
579 void serial8250_rpm_put(struct uart_8250_port *p)
580 {
581 if (!(p->capabilities & UART_CAP_RPM))
582 return;
583 pm_runtime_mark_last_busy(p->port.dev);
584 pm_runtime_put_autosuspend(p->port.dev);
585 }
586 EXPORT_SYMBOL_GPL(serial8250_rpm_put);
587
588 /**
589 * serial8250_em485_init() - put uart_8250_port into rs485 emulating
590 * @p: uart_8250_port port instance
591 *
592 * The function is used to start rs485 software emulating on the
593 * &struct uart_8250_port* @p. Namely, RTS is switched before/after
594 * transmission. The function is idempotent, so it is safe to call it
595 * multiple times.
596 *
597 * The caller MUST enable interrupt on empty shift register before
598 * calling serial8250_em485_init(). This interrupt is not a part of
599 * 8250 standard, but implementation defined.
600 *
601 * The function is supposed to be called from .rs485_config callback
602 * or from any other callback protected with p->port.lock spinlock.
603 *
604 * See also serial8250_em485_destroy()
605 *
606 * Return 0 - success, -errno - otherwise
607 */
608 static int serial8250_em485_init(struct uart_8250_port *p)
609 {
610 if (p->em485)
611 return 0;
612
613 p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
614 if (!p->em485)
615 return -ENOMEM;
616
617 hrtimer_init(&p->em485->stop_tx_timer, CLOCK_MONOTONIC,
618 HRTIMER_MODE_REL);
619 hrtimer_init(&p->em485->start_tx_timer, CLOCK_MONOTONIC,
620 HRTIMER_MODE_REL);
621 p->em485->stop_tx_timer.function = &serial8250_em485_handle_stop_tx;
622 p->em485->start_tx_timer.function = &serial8250_em485_handle_start_tx;
623 p->em485->port = p;
624 p->em485->active_timer = NULL;
625 p->em485->tx_stopped = true;
626
627 p->rs485_stop_tx(p);
628
629 return 0;
630 }
631
632 /**
633 * serial8250_em485_destroy() - put uart_8250_port into normal state
634 * @p: uart_8250_port port instance
635 *
636 * The function is used to stop rs485 software emulating on the
637 * &struct uart_8250_port* @p. The function is idempotent, so it is safe to
638 * call it multiple times.
639 *
640 * The function is supposed to be called from .rs485_config callback
641 * or from any other callback protected with p->port.lock spinlock.
642 *
643 * See also serial8250_em485_init()
644 */
645 void serial8250_em485_destroy(struct uart_8250_port *p)
646 {
647 if (!p->em485)
648 return;
649
650 hrtimer_cancel(&p->em485->start_tx_timer);
651 hrtimer_cancel(&p->em485->stop_tx_timer);
652
653 kfree(p->em485);
654 p->em485 = NULL;
655 }
656 EXPORT_SYMBOL_GPL(serial8250_em485_destroy);
657
658 /**
659 * serial8250_em485_config() - generic ->rs485_config() callback
660 * @port: uart port
661 * @rs485: rs485 settings
662 *
663 * Generic callback usable by 8250 uart drivers to activate rs485 settings
664 * if the uart is incapable of driving RTS as a Transmit Enable signal in
665 * hardware, relying on software emulation instead.
666 */
667 int serial8250_em485_config(struct uart_port *port, struct serial_rs485 *rs485)
668 {
669 struct uart_8250_port *up = up_to_u8250p(port);
670
671 /* pick sane settings if the user hasn't */
672 if (!!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
673 !!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
674 rs485->flags |= SER_RS485_RTS_ON_SEND;
675 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
676 }
677
678 /* clamp the delays to [0, 100ms] */
679 rs485->delay_rts_before_send = min(rs485->delay_rts_before_send, 100U);
680 rs485->delay_rts_after_send = min(rs485->delay_rts_after_send, 100U);
681
682 memset(rs485->padding, 0, sizeof(rs485->padding));
683 port->rs485 = *rs485;
684
685 gpiod_set_value(port->rs485_term_gpio,
686 rs485->flags & SER_RS485_TERMINATE_BUS);
687
688 /*
689 * Both serial8250_em485_init() and serial8250_em485_destroy()
690 * are idempotent.
691 */
692 if (rs485->flags & SER_RS485_ENABLED) {
693 int ret = serial8250_em485_init(up);
694
695 if (ret) {
696 rs485->flags &= ~SER_RS485_ENABLED;
697 port->rs485.flags &= ~SER_RS485_ENABLED;
698 }
699 return ret;
700 }
701
702 serial8250_em485_destroy(up);
703 return 0;
704 }
705 EXPORT_SYMBOL_GPL(serial8250_em485_config);
706
707 /*
708 * These two wrappers ensure that enable_runtime_pm_tx() can be called more than
709 * once and disable_runtime_pm_tx() will still disable RPM because the fifo is
710 * empty and the HW can idle again.
711 */
712 void serial8250_rpm_get_tx(struct uart_8250_port *p)
713 {
714 unsigned char rpm_active;
715
716 if (!(p->capabilities & UART_CAP_RPM))
717 return;
718
719 rpm_active = xchg(&p->rpm_tx_active, 1);
720 if (rpm_active)
721 return;
722 pm_runtime_get_sync(p->port.dev);
723 }
724 EXPORT_SYMBOL_GPL(serial8250_rpm_get_tx);
725
726 void serial8250_rpm_put_tx(struct uart_8250_port *p)
727 {
728 unsigned char rpm_active;
729
730 if (!(p->capabilities & UART_CAP_RPM))
731 return;
732
733 rpm_active = xchg(&p->rpm_tx_active, 0);
734 if (!rpm_active)
735 return;
736 pm_runtime_mark_last_busy(p->port.dev);
737 pm_runtime_put_autosuspend(p->port.dev);
738 }
739 EXPORT_SYMBOL_GPL(serial8250_rpm_put_tx);
740
741 /*
742 * IER sleep support. UARTs which have EFRs need the "extended
743 * capability" bit enabled. Note that on XR16C850s, we need to
744 * reset LCR to write to IER.
745 */
746 static void serial8250_set_sleep(struct uart_8250_port *p, int sleep)
747 {
748 unsigned char lcr = 0, efr = 0;
749
750 serial8250_rpm_get(p);
751
752 if (p->capabilities & UART_CAP_SLEEP) {
753 if (p->capabilities & UART_CAP_EFR) {
754 lcr = serial_in(p, UART_LCR);
755 efr = serial_in(p, UART_EFR);
756 serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
757 serial_out(p, UART_EFR, UART_EFR_ECB);
758 serial_out(p, UART_LCR, 0);
759 }
760 serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
761 if (p->capabilities & UART_CAP_EFR) {
762 serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
763 serial_out(p, UART_EFR, efr);
764 serial_out(p, UART_LCR, lcr);
765 }
766 }
767
768 serial8250_rpm_put(p);
769 }
770
771 #ifdef CONFIG_SERIAL_8250_RSA
772 /*
773 * Attempts to turn on the RSA FIFO. Returns zero on failure.
774 * We set the port uart clock rate if we succeed.
775 */
776 static int __enable_rsa(struct uart_8250_port *up)
777 {
778 unsigned char mode;
779 int result;
780
781 mode = serial_in(up, UART_RSA_MSR);
782 result = mode & UART_RSA_MSR_FIFO;
783
784 if (!result) {
785 serial_out(up, UART_RSA_MSR, mode | UART_RSA_MSR_FIFO);
786 mode = serial_in(up, UART_RSA_MSR);
787 result = mode & UART_RSA_MSR_FIFO;
788 }
789
790 if (result)
791 up->port.uartclk = SERIAL_RSA_BAUD_BASE * 16;
792
793 return result;
794 }
795
796 static void enable_rsa(struct uart_8250_port *up)
797 {
798 if (up->port.type == PORT_RSA) {
799 if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
800 spin_lock_irq(&up->port.lock);
801 __enable_rsa(up);
802 spin_unlock_irq(&up->port.lock);
803 }
804 if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
805 serial_out(up, UART_RSA_FRR, 0);
806 }
807 }
808
809 /*
810 * Attempts to turn off the RSA FIFO. Returns zero on failure.
811 * It is unknown why interrupts were disabled in here. However,
812 * the caller is expected to preserve this behaviour by grabbing
813 * the spinlock before calling this function.
814 */
815 static void disable_rsa(struct uart_8250_port *up)
816 {
817 unsigned char mode;
818 int result;
819
820 if (up->port.type == PORT_RSA &&
821 up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
822 spin_lock_irq(&up->port.lock);
823
824 mode = serial_in(up, UART_RSA_MSR);
825 result = !(mode & UART_RSA_MSR_FIFO);
826
827 if (!result) {
828 serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
829 mode = serial_in(up, UART_RSA_MSR);
830 result = !(mode & UART_RSA_MSR_FIFO);
831 }
832
833 if (result)
834 up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
835 spin_unlock_irq(&up->port.lock);
836 }
837 }
838 #endif /* CONFIG_SERIAL_8250_RSA */
839
840 /*
841 * This is a quickie test to see how big the FIFO is.
842 * It doesn't work at all the time, more's the pity.
843 */
844 static int size_fifo(struct uart_8250_port *up)
845 {
846 unsigned char old_fcr, old_mcr, old_lcr;
847 unsigned short old_dl;
848 int count;
849
850 old_lcr = serial_in(up, UART_LCR);
851 serial_out(up, UART_LCR, 0);
852 old_fcr = serial_in(up, UART_FCR);
853 old_mcr = serial8250_in_MCR(up);
854 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
855 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
856 serial8250_out_MCR(up, UART_MCR_LOOP);
857 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
858 old_dl = serial_dl_read(up);
859 serial_dl_write(up, 0x0001);
860 serial_out(up, UART_LCR, 0x03);
861 for (count = 0; count < 256; count++)
862 serial_out(up, UART_TX, count);
863 mdelay(20);/* FIXME - schedule_timeout */
864 for (count = 0; (serial_in(up, UART_LSR) & UART_LSR_DR) &&
865 (count < 256); count++)
866 serial_in(up, UART_RX);
867 serial_out(up, UART_FCR, old_fcr);
868 serial8250_out_MCR(up, old_mcr);
869 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
870 serial_dl_write(up, old_dl);
871 serial_out(up, UART_LCR, old_lcr);
872
873 return count;
874 }
875
876 /*
877 * Read UART ID using the divisor method - set DLL and DLM to zero
878 * and the revision will be in DLL and device type in DLM. We
879 * preserve the device state across this.
880 */
881 static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
882 {
883 unsigned char old_lcr;
884 unsigned int id, old_dl;
885
886 old_lcr = serial_in(p, UART_LCR);
887 serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
888 old_dl = serial_dl_read(p);
889 serial_dl_write(p, 0);
890 id = serial_dl_read(p);
891 serial_dl_write(p, old_dl);
892
893 serial_out(p, UART_LCR, old_lcr);
894
895 return id;
896 }
897
898 /*
899 * This is a helper routine to autodetect StarTech/Exar/Oxsemi UART's.
900 * When this function is called we know it is at least a StarTech
901 * 16650 V2, but it might be one of several StarTech UARTs, or one of
902 * its clones. (We treat the broken original StarTech 16650 V1 as a
903 * 16550, and why not? Startech doesn't seem to even acknowledge its
904 * existence.)
905 *
906 * What evil have men's minds wrought...
907 */
908 static void autoconfig_has_efr(struct uart_8250_port *up)
909 {
910 unsigned int id1, id2, id3, rev;
911
912 /*
913 * Everything with an EFR has SLEEP
914 */
915 up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
916
917 /*
918 * First we check to see if it's an Oxford Semiconductor UART.
919 *
920 * If we have to do this here because some non-National
921 * Semiconductor clone chips lock up if you try writing to the
922 * LSR register (which serial_icr_read does)
923 */
924
925 /*
926 * Check for Oxford Semiconductor 16C950.
927 *
928 * EFR [4] must be set else this test fails.
929 *
930 * This shouldn't be necessary, but Mike Hudson (Exoray@isys.ca)
931 * claims that it's needed for 952 dual UART's (which are not
932 * recommended for new designs).
933 */
934 up->acr = 0;
935 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
936 serial_out(up, UART_EFR, UART_EFR_ECB);
937 serial_out(up, UART_LCR, 0x00);
938 id1 = serial_icr_read(up, UART_ID1);
939 id2 = serial_icr_read(up, UART_ID2);
940 id3 = serial_icr_read(up, UART_ID3);
941 rev = serial_icr_read(up, UART_REV);
942
943 DEBUG_AUTOCONF("950id=%02x:%02x:%02x:%02x ", id1, id2, id3, rev);
944
945 if (id1 == 0x16 && id2 == 0xC9 &&
946 (id3 == 0x50 || id3 == 0x52 || id3 == 0x54)) {
947 up->port.type = PORT_16C950;
948
949 /*
950 * Enable work around for the Oxford Semiconductor 952 rev B
951 * chip which causes it to seriously miscalculate baud rates
952 * when DLL is 0.
953 */
954 if (id3 == 0x52 && rev == 0x01)
955 up->bugs |= UART_BUG_QUOT;
956 return;
957 }
958
959 /*
960 * We check for a XR16C850 by setting DLL and DLM to 0, and then
961 * reading back DLL and DLM. The chip type depends on the DLM
962 * value read back:
963 * 0x10 - XR16C850 and the DLL contains the chip revision.
964 * 0x12 - XR16C2850.
965 * 0x14 - XR16C854.
966 */
967 id1 = autoconfig_read_divisor_id(up);
968 DEBUG_AUTOCONF("850id=%04x ", id1);
969
970 id2 = id1 >> 8;
971 if (id2 == 0x10 || id2 == 0x12 || id2 == 0x14) {
972 up->port.type = PORT_16850;
973 return;
974 }
975
976 /*
977 * It wasn't an XR16C850.
978 *
979 * We distinguish between the '654 and the '650 by counting
980 * how many bytes are in the FIFO. I'm using this for now,
981 * since that's the technique that was sent to me in the
982 * serial driver update, but I'm not convinced this works.
983 * I've had problems doing this in the past. -TYT
984 */
985 if (size_fifo(up) == 64)
986 up->port.type = PORT_16654;
987 else
988 up->port.type = PORT_16650V2;
989 }
990
991 /*
992 * We detected a chip without a FIFO. Only two fall into
993 * this category - the original 8250 and the 16450. The
994 * 16450 has a scratch register (accessible with LCR=0)
995 */
996 static void autoconfig_8250(struct uart_8250_port *up)
997 {
998 unsigned char scratch, status1, status2;
999
1000 up->port.type = PORT_8250;
1001
1002 scratch = serial_in(up, UART_SCR);
1003 serial_out(up, UART_SCR, 0xa5);
1004 status1 = serial_in(up, UART_SCR);
1005 serial_out(up, UART_SCR, 0x5a);
1006 status2 = serial_in(up, UART_SCR);
1007 serial_out(up, UART_SCR, scratch);
1008
1009 if (status1 == 0xa5 && status2 == 0x5a)
1010 up->port.type = PORT_16450;
1011 }
1012
1013 static int broken_efr(struct uart_8250_port *up)
1014 {
1015 /*
1016 * Exar ST16C2550 "A2" devices incorrectly detect as
1017 * having an EFR, and report an ID of 0x0201. See
1018 * http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-11/4812.html
1019 */
1020 if (autoconfig_read_divisor_id(up) == 0x0201 && size_fifo(up) == 16)
1021 return 1;
1022
1023 return 0;
1024 }
1025
1026 /*
1027 * We know that the chip has FIFOs. Does it have an EFR? The
1028 * EFR is located in the same register position as the IIR and
1029 * we know the top two bits of the IIR are currently set. The
1030 * EFR should contain zero. Try to read the EFR.
1031 */
1032 static void autoconfig_16550a(struct uart_8250_port *up)
1033 {
1034 unsigned char status1, status2;
1035 unsigned int iersave;
1036
1037 up->port.type = PORT_16550A;
1038 up->capabilities |= UART_CAP_FIFO;
1039
1040 if (!IS_ENABLED(CONFIG_SERIAL_8250_16550A_VARIANTS))
1041 return;
1042
1043 /*
1044 * Check for presence of the EFR when DLAB is set.
1045 * Only ST16C650V1 UARTs pass this test.
1046 */
1047 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
1048 if (serial_in(up, UART_EFR) == 0) {
1049 serial_out(up, UART_EFR, 0xA8);
1050 if (serial_in(up, UART_EFR) != 0) {
1051 DEBUG_AUTOCONF("EFRv1 ");
1052 up->port.type = PORT_16650;
1053 up->capabilities |= UART_CAP_EFR | UART_CAP_SLEEP;
1054 } else {
1055 serial_out(up, UART_LCR, 0);
1056 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
1057 UART_FCR7_64BYTE);
1058 status1 = serial_in(up, UART_IIR) >> 5;
1059 serial_out(up, UART_FCR, 0);
1060 serial_out(up, UART_LCR, 0);
1061
1062 if (status1 == 7)
1063 up->port.type = PORT_16550A_FSL64;
1064 else
1065 DEBUG_AUTOCONF("Motorola 8xxx DUART ");
1066 }
1067 serial_out(up, UART_EFR, 0);
1068 return;
1069 }
1070
1071 /*
1072 * Maybe it requires 0xbf to be written to the LCR.
1073 * (other ST16C650V2 UARTs, TI16C752A, etc)
1074 */
1075 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
1076 if (serial_in(up, UART_EFR) == 0 && !broken_efr(up)) {
1077 DEBUG_AUTOCONF("EFRv2 ");
1078 autoconfig_has_efr(up);
1079 return;
1080 }
1081
1082 /*
1083 * Check for a National Semiconductor SuperIO chip.
1084 * Attempt to switch to bank 2, read the value of the LOOP bit
1085 * from EXCR1. Switch back to bank 0, change it in MCR. Then
1086 * switch back to bank 2, read it from EXCR1 again and check
1087 * it's changed. If so, set baud_base in EXCR2 to 921600. -- dwmw2
1088 */
1089 serial_out(up, UART_LCR, 0);
1090 status1 = serial8250_in_MCR(up);
1091 serial_out(up, UART_LCR, 0xE0);
1092 status2 = serial_in(up, 0x02); /* EXCR1 */
1093
1094 if (!((status2 ^ status1) & UART_MCR_LOOP)) {
1095 serial_out(up, UART_LCR, 0);
1096 serial8250_out_MCR(up, status1 ^ UART_MCR_LOOP);
1097 serial_out(up, UART_LCR, 0xE0);
1098 status2 = serial_in(up, 0x02); /* EXCR1 */
1099 serial_out(up, UART_LCR, 0);
1100 serial8250_out_MCR(up, status1);
1101
1102 if ((status2 ^ status1) & UART_MCR_LOOP) {
1103 unsigned short quot;
1104
1105 serial_out(up, UART_LCR, 0xE0);
1106
1107 quot = serial_dl_read(up);
1108 quot <<= 3;
1109
1110 if (ns16550a_goto_highspeed(up))
1111 serial_dl_write(up, quot);
1112
1113 serial_out(up, UART_LCR, 0);
1114
1115 up->port.uartclk = 921600*16;
1116 up->port.type = PORT_NS16550A;
1117 up->capabilities |= UART_NATSEMI;
1118 return;
1119 }
1120 }
1121
1122 /*
1123 * No EFR. Try to detect a TI16750, which only sets bit 5 of
1124 * the IIR when 64 byte FIFO mode is enabled when DLAB is set.
1125 * Try setting it with and without DLAB set. Cheap clones
1126 * set bit 5 without DLAB set.
1127 */
1128 serial_out(up, UART_LCR, 0);
1129 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
1130 status1 = serial_in(up, UART_IIR) >> 5;
1131 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
1132 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
1133 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
1134 status2 = serial_in(up, UART_IIR) >> 5;
1135 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
1136 serial_out(up, UART_LCR, 0);
1137
1138 DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
1139
1140 if (status1 == 6 && status2 == 7) {
1141 up->port.type = PORT_16750;
1142 up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
1143 return;
1144 }
1145
1146 /*
1147 * Try writing and reading the UART_IER_UUE bit (b6).
1148 * If it works, this is probably one of the Xscale platform's
1149 * internal UARTs.
1150 * We're going to explicitly set the UUE bit to 0 before
1151 * trying to write and read a 1 just to make sure it's not
1152 * already a 1 and maybe locked there before we even start start.
1153 */
1154 iersave = serial_in(up, UART_IER);
1155 serial_out(up, UART_IER, iersave & ~UART_IER_UUE);
1156 if (!(serial_in(up, UART_IER) & UART_IER_UUE)) {
1157 /*
1158 * OK it's in a known zero state, try writing and reading
1159 * without disturbing the current state of the other bits.
1160 */
1161 serial_out(up, UART_IER, iersave | UART_IER_UUE);
1162 if (serial_in(up, UART_IER) & UART_IER_UUE) {
1163 /*
1164 * It's an Xscale.
1165 * We'll leave the UART_IER_UUE bit set to 1 (enabled).
1166 */
1167 DEBUG_AUTOCONF("Xscale ");
1168 up->port.type = PORT_XSCALE;
1169 up->capabilities |= UART_CAP_UUE | UART_CAP_RTOIE;
1170 return;
1171 }
1172 } else {
1173 /*
1174 * If we got here we couldn't force the IER_UUE bit to 0.
1175 * Log it and continue.
1176 */
1177 DEBUG_AUTOCONF("Couldn't force IER_UUE to 0 ");
1178 }
1179 serial_out(up, UART_IER, iersave);
1180
1181 /*
1182 * We distinguish between 16550A and U6 16550A by counting
1183 * how many bytes are in the FIFO.
1184 */
1185 if (up->port.type == PORT_16550A && size_fifo(up) == 64) {
1186 up->port.type = PORT_U6_16550A;
1187 up->capabilities |= UART_CAP_AFE;
1188 }
1189 }
1190
1191 /*
1192 * This routine is called by rs_init() to initialize a specific serial
1193 * port. It determines what type of UART chip this serial port is
1194 * using: 8250, 16450, 16550, 16550A. The important question is
1195 * whether or not this UART is a 16550A or not, since this will
1196 * determine whether or not we can use its FIFO features or not.
1197 */
1198 static void autoconfig(struct uart_8250_port *up)
1199 {
1200 unsigned char status1, scratch, scratch2, scratch3;
1201 unsigned char save_lcr, save_mcr;
1202 struct uart_port *port = &up->port;
1203 unsigned long flags;
1204 unsigned int old_capabilities;
1205
1206 if (!port->iobase && !port->mapbase && !port->membase)
1207 return;
1208
1209 DEBUG_AUTOCONF("%s: autoconf (0x%04lx, 0x%p): ",
1210 port->name, port->iobase, port->membase);
1211
1212 /*
1213 * We really do need global IRQs disabled here - we're going to
1214 * be frobbing the chips IRQ enable register to see if it exists.
1215 */
1216 spin_lock_irqsave(&port->lock, flags);
1217
1218 up->capabilities = 0;
1219 up->bugs = 0;
1220
1221 if (!(port->flags & UPF_BUGGY_UART)) {
1222 /*
1223 * Do a simple existence test first; if we fail this,
1224 * there's no point trying anything else.
1225 *
1226 * 0x80 is used as a nonsense port to prevent against
1227 * false positives due to ISA bus float. The
1228 * assumption is that 0x80 is a non-existent port;
1229 * which should be safe since include/asm/io.h also
1230 * makes this assumption.
1231 *
1232 * Note: this is safe as long as MCR bit 4 is clear
1233 * and the device is in "PC" mode.
1234 */
1235 scratch = serial_in(up, UART_IER);
1236 serial_out(up, UART_IER, 0);
1237 #ifdef __i386__
1238 outb(0xff, 0x080);
1239 #endif
1240 /*
1241 * Mask out IER[7:4] bits for test as some UARTs (e.g. TL
1242 * 16C754B) allow only to modify them if an EFR bit is set.
1243 */
1244 scratch2 = serial_in(up, UART_IER) & 0x0f;
1245 serial_out(up, UART_IER, 0x0F);
1246 #ifdef __i386__
1247 outb(0, 0x080);
1248 #endif
1249 scratch3 = serial_in(up, UART_IER) & 0x0f;
1250 serial_out(up, UART_IER, scratch);
1251 if (scratch2 != 0 || scratch3 != 0x0F) {
1252 /*
1253 * We failed; there's nothing here
1254 */
1255 spin_unlock_irqrestore(&port->lock, flags);
1256 DEBUG_AUTOCONF("IER test failed (%02x, %02x) ",
1257 scratch2, scratch3);
1258 goto out;
1259 }
1260 }
1261
1262 save_mcr = serial8250_in_MCR(up);
1263 save_lcr = serial_in(up, UART_LCR);
1264
1265 /*
1266 * Check to see if a UART is really there. Certain broken
1267 * internal modems based on the Rockwell chipset fail this
1268 * test, because they apparently don't implement the loopback
1269 * test mode. So this test is skipped on the COM 1 through
1270 * COM 4 ports. This *should* be safe, since no board
1271 * manufacturer would be stupid enough to design a board
1272 * that conflicts with COM 1-4 --- we hope!
1273 */
1274 if (!(port->flags & UPF_SKIP_TEST)) {
1275 serial8250_out_MCR(up, UART_MCR_LOOP | 0x0A);
1276 status1 = serial_in(up, UART_MSR) & 0xF0;
1277 serial8250_out_MCR(up, save_mcr);
1278 if (status1 != 0x90) {
1279 spin_unlock_irqrestore(&port->lock, flags);
1280 DEBUG_AUTOCONF("LOOP test failed (%02x) ",
1281 status1);
1282 goto out;
1283 }
1284 }
1285
1286 /*
1287 * We're pretty sure there's a port here. Lets find out what
1288 * type of port it is. The IIR top two bits allows us to find
1289 * out if it's 8250 or 16450, 16550, 16550A or later. This
1290 * determines what we test for next.
1291 *
1292 * We also initialise the EFR (if any) to zero for later. The
1293 * EFR occupies the same register location as the FCR and IIR.
1294 */
1295 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
1296 serial_out(up, UART_EFR, 0);
1297 serial_out(up, UART_LCR, 0);
1298
1299 serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
1300 scratch = serial_in(up, UART_IIR) >> 6;
1301
1302 switch (scratch) {
1303 case 0:
1304 autoconfig_8250(up);
1305 break;
1306 case 1:
1307 port->type = PORT_UNKNOWN;
1308 break;
1309 case 2:
1310 port->type = PORT_16550;
1311 break;
1312 case 3:
1313 autoconfig_16550a(up);
1314 break;
1315 }
1316
1317 #ifdef CONFIG_SERIAL_8250_RSA
1318 /*
1319 * Only probe for RSA ports if we got the region.
1320 */
1321 if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
1322 __enable_rsa(up))
1323 port->type = PORT_RSA;
1324 #endif
1325
1326 serial_out(up, UART_LCR, save_lcr);
1327
1328 port->fifosize = uart_config[up->port.type].fifo_size;
1329 old_capabilities = up->capabilities;
1330 up->capabilities = uart_config[port->type].flags;
1331 up->tx_loadsz = uart_config[port->type].tx_loadsz;
1332
1333 if (port->type == PORT_UNKNOWN)
1334 goto out_lock;
1335
1336 /*
1337 * Reset the UART.
1338 */
1339 #ifdef CONFIG_SERIAL_8250_RSA
1340 if (port->type == PORT_RSA)
1341 serial_out(up, UART_RSA_FRR, 0);
1342 #endif
1343 serial8250_out_MCR(up, save_mcr);
1344 serial8250_clear_fifos(up);
1345 serial_in(up, UART_RX);
1346 if (up->capabilities & UART_CAP_UUE)
1347 serial_out(up, UART_IER, UART_IER_UUE);
1348 else
1349 serial_out(up, UART_IER, 0);
1350
1351 out_lock:
1352 spin_unlock_irqrestore(&port->lock, flags);
1353
1354 /*
1355 * Check if the device is a Fintek F81216A
1356 */
1357 if (port->type == PORT_16550A && port->iotype == UPIO_PORT)
1358 fintek_8250_probe(up);
1359
1360 if (up->capabilities != old_capabilities) {
1361 dev_warn(port->dev, "detected caps %08x should be %08x\n",
1362 old_capabilities, up->capabilities);
1363 }
1364 out:
1365 DEBUG_AUTOCONF("iir=%d ", scratch);
1366 DEBUG_AUTOCONF("type=%s\n", uart_config[port->type].name);
1367 }
1368
1369 static void autoconfig_irq(struct uart_8250_port *up)
1370 {
1371 struct uart_port *port = &up->port;
1372 unsigned char save_mcr, save_ier;
1373 unsigned char save_ICP = 0;
1374 unsigned int ICP = 0;
1375 unsigned long irqs;
1376 int irq;
1377
1378 if (port->flags & UPF_FOURPORT) {
1379 ICP = (port->iobase & 0xfe0) | 0x1f;
1380 save_ICP = inb_p(ICP);
1381 outb_p(0x80, ICP);
1382 inb_p(ICP);
1383 }
1384
1385 if (uart_console(port))
1386 console_lock();
1387
1388 /* forget possible initially masked and pending IRQ */
1389 probe_irq_off(probe_irq_on());
1390 save_mcr = serial8250_in_MCR(up);
1391 save_ier = serial_in(up, UART_IER);
1392 serial8250_out_MCR(up, UART_MCR_OUT1 | UART_MCR_OUT2);
1393
1394 irqs = probe_irq_on();
1395 serial8250_out_MCR(up, 0);
1396 udelay(10);
1397 if (port->flags & UPF_FOURPORT) {
1398 serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
1399 } else {
1400 serial8250_out_MCR(up,
1401 UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2);
1402 }
1403 serial_out(up, UART_IER, 0x0f); /* enable all intrs */
1404 serial_in(up, UART_LSR);
1405 serial_in(up, UART_RX);
1406 serial_in(up, UART_IIR);
1407 serial_in(up, UART_MSR);
1408 serial_out(up, UART_TX, 0xFF);
1409 udelay(20);
1410 irq = probe_irq_off(irqs);
1411
1412 serial8250_out_MCR(up, save_mcr);
1413 serial_out(up, UART_IER, save_ier);
1414
1415 if (port->flags & UPF_FOURPORT)
1416 outb_p(save_ICP, ICP);
1417
1418 if (uart_console(port))
1419 console_unlock();
1420
1421 port->irq = (irq > 0) ? irq : 0;
1422 }
1423
1424 static void serial8250_stop_rx(struct uart_port *port)
1425 {
1426 struct uart_8250_port *up = up_to_u8250p(port);
1427
1428 serial8250_rpm_get(up);
1429
1430 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
1431 up->port.read_status_mask &= ~UART_LSR_DR;
1432 serial_port_out(port, UART_IER, up->ier);
1433
1434 serial8250_rpm_put(up);
1435 }
1436
1437 /**
1438 * serial8250_em485_stop_tx() - generic ->rs485_stop_tx() callback
1439 * @p: uart 8250 port
1440 *
1441 * Generic callback usable by 8250 uart drivers to stop rs485 transmission.
1442 */
1443 void serial8250_em485_stop_tx(struct uart_8250_port *p)
1444 {
1445 unsigned char mcr = serial8250_in_MCR(p);
1446
1447 if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
1448 mcr |= UART_MCR_RTS;
1449 else
1450 mcr &= ~UART_MCR_RTS;
1451 serial8250_out_MCR(p, mcr);
1452
1453 /*
1454 * Empty the RX FIFO, we are not interested in anything
1455 * received during the half-duplex transmission.
1456 * Enable previously disabled RX interrupts.
1457 */
1458 if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX)) {
1459 serial8250_clear_and_reinit_fifos(p);
1460
1461 p->ier |= UART_IER_RLSI | UART_IER_RDI;
1462 serial_port_out(&p->port, UART_IER, p->ier);
1463 }
1464 }
1465 EXPORT_SYMBOL_GPL(serial8250_em485_stop_tx);
1466
1467 static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
1468 {
1469 struct uart_8250_em485 *em485;
1470 struct uart_8250_port *p;
1471 unsigned long flags;
1472
1473 em485 = container_of(t, struct uart_8250_em485, stop_tx_timer);
1474 p = em485->port;
1475
1476 serial8250_rpm_get(p);
1477 spin_lock_irqsave(&p->port.lock, flags);
1478 if (em485->active_timer == &em485->stop_tx_timer) {
1479 p->rs485_stop_tx(p);
1480 em485->active_timer = NULL;
1481 em485->tx_stopped = true;
1482 }
1483 spin_unlock_irqrestore(&p->port.lock, flags);
1484 serial8250_rpm_put(p);
1485 return HRTIMER_NORESTART;
1486 }
1487
1488 static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
1489 {
1490 long sec = msec / 1000;
1491 long nsec = (msec % 1000) * 1000000;
1492 ktime_t t = ktime_set(sec, nsec);
1493
1494 hrtimer_start(hrt, t, HRTIMER_MODE_REL);
1495 }
1496
1497 static void __stop_tx_rs485(struct uart_8250_port *p)
1498 {
1499 struct uart_8250_em485 *em485 = p->em485;
1500
1501 /*
1502 * rs485_stop_tx() is going to set RTS according to config
1503 * AND flush RX FIFO if required.
1504 */
1505 if (p->port.rs485.delay_rts_after_send > 0) {
1506 em485->active_timer = &em485->stop_tx_timer;
1507 start_hrtimer_ms(&em485->stop_tx_timer,
1508 p->port.rs485.delay_rts_after_send);
1509 } else {
1510 p->rs485_stop_tx(p);
1511 em485->active_timer = NULL;
1512 em485->tx_stopped = true;
1513 }
1514 }
1515
1516 static inline void __do_stop_tx(struct uart_8250_port *p)
1517 {
1518 if (serial8250_clear_THRI(p))
1519 serial8250_rpm_put_tx(p);
1520 }
1521
1522 static inline void __stop_tx(struct uart_8250_port *p)
1523 {
1524 struct uart_8250_em485 *em485 = p->em485;
1525
1526 if (em485) {
1527 unsigned char lsr = serial_in(p, UART_LSR);
1528 /*
1529 * To provide required timeing and allow FIFO transfer,
1530 * __stop_tx_rs485() must be called only when both FIFO and
1531 * shift register are empty. It is for device driver to enable
1532 * interrupt on TEMT.
1533 */
1534 if ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
1535 return;
1536
1537 __stop_tx_rs485(p);
1538 }
1539 __do_stop_tx(p);
1540 }
1541
1542 static void serial8250_stop_tx(struct uart_port *port)
1543 {
1544 struct uart_8250_port *up = up_to_u8250p(port);
1545
1546 serial8250_rpm_get(up);
1547 __stop_tx(up);
1548
1549 /*
1550 * We really want to stop the transmitter from sending.
1551 */
1552 if (port->type == PORT_16C950) {
1553 up->acr |= UART_ACR_TXDIS;
1554 serial_icr_write(up, UART_ACR, up->acr);
1555 }
1556 serial8250_rpm_put(up);
1557 }
1558
1559 static inline void __start_tx(struct uart_port *port)
1560 {
1561 struct uart_8250_port *up = up_to_u8250p(port);
1562
1563 if (up->dma && !up->dma->tx_dma(up))
1564 return;
1565
1566 if (serial8250_set_THRI(up)) {
1567 if (up->bugs & UART_BUG_TXEN) {
1568 unsigned char lsr;
1569
1570 lsr = serial_in(up, UART_LSR);
1571 up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
1572 if (lsr & UART_LSR_THRE)
1573 serial8250_tx_chars(up);
1574 }
1575 }
1576
1577 /*
1578 * Re-enable the transmitter if we disabled it.
1579 */
1580 if (port->type == PORT_16C950 && up->acr & UART_ACR_TXDIS) {
1581 up->acr &= ~UART_ACR_TXDIS;
1582 serial_icr_write(up, UART_ACR, up->acr);
1583 }
1584 }
1585
1586 /**
1587 * serial8250_em485_start_tx() - generic ->rs485_start_tx() callback
1588 * @up: uart 8250 port
1589 *
1590 * Generic callback usable by 8250 uart drivers to start rs485 transmission.
1591 * Assumes that setting the RTS bit in the MCR register means RTS is high.
1592 * (Some chips use inverse semantics.) Further assumes that reception is
1593 * stoppable by disabling the UART_IER_RDI interrupt. (Some chips set the
1594 * UART_LSR_DR bit even when UART_IER_RDI is disabled, foiling this approach.)
1595 */
1596 void serial8250_em485_start_tx(struct uart_8250_port *up)
1597 {
1598 unsigned char mcr = serial8250_in_MCR(up);
1599
1600 if (!(up->port.rs485.flags & SER_RS485_RX_DURING_TX))
1601 serial8250_stop_rx(&up->port);
1602
1603 if (up->port.rs485.flags & SER_RS485_RTS_ON_SEND)
1604 mcr |= UART_MCR_RTS;
1605 else
1606 mcr &= ~UART_MCR_RTS;
1607 serial8250_out_MCR(up, mcr);
1608 }
1609 EXPORT_SYMBOL_GPL(serial8250_em485_start_tx);
1610
1611 static inline void start_tx_rs485(struct uart_port *port)
1612 {
1613 struct uart_8250_port *up = up_to_u8250p(port);
1614 struct uart_8250_em485 *em485 = up->em485;
1615
1616 em485->active_timer = NULL;
1617
1618 if (em485->tx_stopped) {
1619 em485->tx_stopped = false;
1620
1621 up->rs485_start_tx(up);
1622
1623 if (up->port.rs485.delay_rts_before_send > 0) {
1624 em485->active_timer = &em485->start_tx_timer;
1625 start_hrtimer_ms(&em485->start_tx_timer,
1626 up->port.rs485.delay_rts_before_send);
1627 return;
1628 }
1629 }
1630
1631 __start_tx(port);
1632 }
1633
1634 static enum hrtimer_restart serial8250_em485_handle_start_tx(struct hrtimer *t)
1635 {
1636 struct uart_8250_em485 *em485;
1637 struct uart_8250_port *p;
1638 unsigned long flags;
1639
1640 em485 = container_of(t, struct uart_8250_em485, start_tx_timer);
1641 p = em485->port;
1642
1643 spin_lock_irqsave(&p->port.lock, flags);
1644 if (em485->active_timer == &em485->start_tx_timer) {
1645 __start_tx(&p->port);
1646 em485->active_timer = NULL;
1647 }
1648 spin_unlock_irqrestore(&p->port.lock, flags);
1649 return HRTIMER_NORESTART;
1650 }
1651
1652 static void serial8250_start_tx(struct uart_port *port)
1653 {
1654 struct uart_8250_port *up = up_to_u8250p(port);
1655 struct uart_8250_em485 *em485 = up->em485;
1656
1657 serial8250_rpm_get_tx(up);
1658
1659 if (em485 &&
1660 em485->active_timer == &em485->start_tx_timer)
1661 return;
1662
1663 if (em485)
1664 start_tx_rs485(port);
1665 else
1666 __start_tx(port);
1667 }
1668
1669 static void serial8250_throttle(struct uart_port *port)
1670 {
1671 port->throttle(port);
1672 }
1673
1674 static void serial8250_unthrottle(struct uart_port *port)
1675 {
1676 port->unthrottle(port);
1677 }
1678
1679 static void serial8250_disable_ms(struct uart_port *port)
1680 {
1681 struct uart_8250_port *up = up_to_u8250p(port);
1682
1683 /* no MSR capabilities */
1684 if (up->bugs & UART_BUG_NOMSR)
1685 return;
1686
1687 mctrl_gpio_disable_ms(up->gpios);
1688
1689 up->ier &= ~UART_IER_MSI;
1690 serial_port_out(port, UART_IER, up->ier);
1691 }
1692
1693 static void serial8250_enable_ms(struct uart_port *port)
1694 {
1695 struct uart_8250_port *up = up_to_u8250p(port);
1696
1697 /* no MSR capabilities */
1698 if (up->bugs & UART_BUG_NOMSR)
1699 return;
1700
1701 mctrl_gpio_enable_ms(up->gpios);
1702
1703 up->ier |= UART_IER_MSI;
1704
1705 serial8250_rpm_get(up);
1706 serial_port_out(port, UART_IER, up->ier);
1707 serial8250_rpm_put(up);
1708 }
1709
1710 void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
1711 {
1712 struct uart_port *port = &up->port;
1713 unsigned char ch;
1714 char flag = TTY_NORMAL;
1715
1716 if (likely(lsr & UART_LSR_DR))
1717 ch = serial_in(up, UART_RX);
1718 else
1719 /*
1720 * Intel 82571 has a Serial Over Lan device that will
1721 * set UART_LSR_BI without setting UART_LSR_DR when
1722 * it receives a break. To avoid reading from the
1723 * receive buffer without UART_LSR_DR bit set, we
1724 * just force the read character to be 0
1725 */
1726 ch = 0;
1727
1728 port->icount.rx++;
1729
1730 lsr |= up->lsr_saved_flags;
1731 up->lsr_saved_flags = 0;
1732
1733 if (unlikely(lsr & UART_LSR_BRK_ERROR_BITS)) {
1734 if (lsr & UART_LSR_BI) {
1735 lsr &= ~(UART_LSR_FE | UART_LSR_PE);
1736 port->icount.brk++;
1737 /*
1738 * We do the SysRQ and SAK checking
1739 * here because otherwise the break
1740 * may get masked by ignore_status_mask
1741 * or read_status_mask.
1742 */
1743 if (uart_handle_break(port))
1744 return;
1745 } else if (lsr & UART_LSR_PE)
1746 port->icount.parity++;
1747 else if (lsr & UART_LSR_FE)
1748 port->icount.frame++;
1749 if (lsr & UART_LSR_OE)
1750 port->icount.overrun++;
1751
1752 /*
1753 * Mask off conditions which should be ignored.
1754 */
1755 lsr &= port->read_status_mask;
1756
1757 if (lsr & UART_LSR_BI) {
1758 dev_dbg(port->dev, "handling break\n");
1759 flag = TTY_BREAK;
1760 } else if (lsr & UART_LSR_PE)
1761 flag = TTY_PARITY;
1762 else if (lsr & UART_LSR_FE)
1763 flag = TTY_FRAME;
1764 }
1765 if (uart_prepare_sysrq_char(port, ch))
1766 return;
1767
1768 uart_insert_char(port, lsr, UART_LSR_OE, ch, flag);
1769 }
1770 EXPORT_SYMBOL_GPL(serial8250_read_char);
1771
1772 /*
1773 * serial8250_rx_chars: processes according to the passed in LSR
1774 * value, and returns the remaining LSR bits not handled
1775 * by this Rx routine.
1776 */
1777 unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
1778 {
1779 struct uart_port *port = &up->port;
1780 int max_count = 256;
1781
1782 do {
1783 serial8250_read_char(up, lsr);
1784 if (--max_count == 0)
1785 break;
1786 lsr = serial_in(up, UART_LSR);
1787 } while (lsr & (UART_LSR_DR | UART_LSR_BI));
1788
1789 tty_flip_buffer_push(&port->state->port);
1790 return lsr;
1791 }
1792 EXPORT_SYMBOL_GPL(serial8250_rx_chars);
1793
1794 void serial8250_tx_chars(struct uart_8250_port *up)
1795 {
1796 struct uart_port *port = &up->port;
1797 struct circ_buf *xmit = &port->state->xmit;
1798 int count;
1799
1800 if (port->x_char) {
1801 serial_out(up, UART_TX, port->x_char);
1802 port->icount.tx++;
1803 port->x_char = 0;
1804 return;
1805 }
1806 if (uart_tx_stopped(port)) {
1807 serial8250_stop_tx(port);
1808 return;
1809 }
1810 if (uart_circ_empty(xmit)) {
1811 __stop_tx(up);
1812 return;
1813 }
1814
1815 count = up->tx_loadsz;
1816 do {
1817 serial_out(up, UART_TX, xmit->buf[xmit->tail]);
1818 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1819 port->icount.tx++;
1820 if (uart_circ_empty(xmit))
1821 break;
1822 if ((up->capabilities & UART_CAP_HFIFO) &&
1823 (serial_in(up, UART_LSR) & BOTH_EMPTY) != BOTH_EMPTY)
1824 break;
1825 /* The BCM2835 MINI UART THRE bit is really a not-full bit. */
1826 if ((up->capabilities & UART_CAP_MINI) &&
1827 !(serial_in(up, UART_LSR) & UART_LSR_THRE))
1828 break;
1829 } while (--count > 0);
1830
1831 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1832 uart_write_wakeup(port);
1833
1834 /*
1835 * With RPM enabled, we have to wait until the FIFO is empty before the
1836 * HW can go idle. So we get here once again with empty FIFO and disable
1837 * the interrupt and RPM in __stop_tx()
1838 */
1839 if (uart_circ_empty(xmit) && !(up->capabilities & UART_CAP_RPM))
1840 __stop_tx(up);
1841 }
1842 EXPORT_SYMBOL_GPL(serial8250_tx_chars);
1843
1844 /* Caller holds uart port lock */
1845 unsigned int serial8250_modem_status(struct uart_8250_port *up)
1846 {
1847 struct uart_port *port = &up->port;
1848 unsigned int status = serial_in(up, UART_MSR);
1849
1850 status |= up->msr_saved_flags;
1851 up->msr_saved_flags = 0;
1852 if (status & UART_MSR_ANY_DELTA && up->ier & UART_IER_MSI &&
1853 port->state != NULL) {
1854 if (status & UART_MSR_TERI)
1855 port->icount.rng++;
1856 if (status & UART_MSR_DDSR)
1857 port->icount.dsr++;
1858 if (status & UART_MSR_DDCD)
1859 uart_handle_dcd_change(port, status & UART_MSR_DCD);
1860 if (status & UART_MSR_DCTS)
1861 uart_handle_cts_change(port, status & UART_MSR_CTS);
1862
1863 wake_up_interruptible(&port->state->port.delta_msr_wait);
1864 }
1865
1866 return status;
1867 }
1868 EXPORT_SYMBOL_GPL(serial8250_modem_status);
1869
1870 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
1871 {
1872 switch (iir & 0x3f) {
1873 case UART_IIR_RX_TIMEOUT:
1874 serial8250_rx_dma_flush(up);
1875 fallthrough;
1876 case UART_IIR_RLSI:
1877 return true;
1878 }
1879 return up->dma->rx_dma(up);
1880 }
1881
1882 /*
1883 * This handles the interrupt from one port.
1884 */
1885 int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
1886 {
1887 unsigned char status;
1888 unsigned long flags;
1889 struct uart_8250_port *up = up_to_u8250p(port);
1890 bool skip_rx = false;
1891
1892 if (iir & UART_IIR_NO_INT)
1893 return 0;
1894
1895 spin_lock_irqsave(&port->lock, flags);
1896
1897 status = serial_port_in(port, UART_LSR);
1898
1899 /*
1900 * If port is stopped and there are no error conditions in the
1901 * FIFO, then don't drain the FIFO, as this may lead to TTY buffer
1902 * overflow. Not servicing, RX FIFO would trigger auto HW flow
1903 * control when FIFO occupancy reaches preset threshold, thus
1904 * halting RX. This only works when auto HW flow control is
1905 * available.
1906 */
1907 if (!(status & (UART_LSR_FIFOE | UART_LSR_BRK_ERROR_BITS)) &&
1908 (port->status & (UPSTAT_AUTOCTS | UPSTAT_AUTORTS)) &&
1909 !(port->read_status_mask & UART_LSR_DR))
1910 skip_rx = true;
1911
1912 if (status & (UART_LSR_DR | UART_LSR_BI) && !skip_rx) {
1913 if (!up->dma || handle_rx_dma(up, iir))
1914 status = serial8250_rx_chars(up, status);
1915 }
1916 serial8250_modem_status(up);
1917 if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE) &&
1918 (up->ier & UART_IER_THRI))
1919 serial8250_tx_chars(up);
1920
1921 uart_unlock_and_check_sysrq(port, flags);
1922 return 1;
1923 }
1924 EXPORT_SYMBOL_GPL(serial8250_handle_irq);
1925
1926 static int serial8250_default_handle_irq(struct uart_port *port)
1927 {
1928 struct uart_8250_port *up = up_to_u8250p(port);
1929 unsigned int iir;
1930 int ret;
1931
1932 serial8250_rpm_get(up);
1933
1934 iir = serial_port_in(port, UART_IIR);
1935 ret = serial8250_handle_irq(port, iir);
1936
1937 serial8250_rpm_put(up);
1938 return ret;
1939 }
1940
1941 /*
1942 * Newer 16550 compatible parts such as the SC16C650 & Altera 16550 Soft IP
1943 * have a programmable TX threshold that triggers the THRE interrupt in
1944 * the IIR register. In this case, the THRE interrupt indicates the FIFO
1945 * has space available. Load it up with tx_loadsz bytes.
1946 */
1947 static int serial8250_tx_threshold_handle_irq(struct uart_port *port)
1948 {
1949 unsigned long flags;
1950 unsigned int iir = serial_port_in(port, UART_IIR);
1951
1952 /* TX Threshold IRQ triggered so load up FIFO */
1953 if ((iir & UART_IIR_ID) == UART_IIR_THRI) {
1954 struct uart_8250_port *up = up_to_u8250p(port);
1955
1956 spin_lock_irqsave(&port->lock, flags);
1957 serial8250_tx_chars(up);
1958 spin_unlock_irqrestore(&port->lock, flags);
1959 }
1960
1961 iir = serial_port_in(port, UART_IIR);
1962 return serial8250_handle_irq(port, iir);
1963 }
1964
1965 static unsigned int serial8250_tx_empty(struct uart_port *port)
1966 {
1967 struct uart_8250_port *up = up_to_u8250p(port);
1968 unsigned long flags;
1969 unsigned int lsr;
1970
1971 serial8250_rpm_get(up);
1972
1973 spin_lock_irqsave(&port->lock, flags);
1974 lsr = serial_port_in(port, UART_LSR);
1975 up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
1976 spin_unlock_irqrestore(&port->lock, flags);
1977
1978 serial8250_rpm_put(up);
1979
1980 return (lsr & BOTH_EMPTY) == BOTH_EMPTY ? TIOCSER_TEMT : 0;
1981 }
1982
1983 unsigned int serial8250_do_get_mctrl(struct uart_port *port)
1984 {
1985 struct uart_8250_port *up = up_to_u8250p(port);
1986 unsigned int status;
1987 unsigned int val;
1988
1989 serial8250_rpm_get(up);
1990 status = serial8250_modem_status(up);
1991 serial8250_rpm_put(up);
1992
1993 val = serial8250_MSR_to_TIOCM(status);
1994 if (up->gpios)
1995 return mctrl_gpio_get(up->gpios, &val);
1996
1997 return val;
1998 }
1999 EXPORT_SYMBOL_GPL(serial8250_do_get_mctrl);
2000
2001 static unsigned int serial8250_get_mctrl(struct uart_port *port)
2002 {
2003 if (port->get_mctrl)
2004 return port->get_mctrl(port);
2005 return serial8250_do_get_mctrl(port);
2006 }
2007
2008 void serial8250_do_set_mctrl(struct uart_port *port, unsigned int mctrl)
2009 {
2010 struct uart_8250_port *up = up_to_u8250p(port);
2011 unsigned char mcr;
2012
2013 if (port->rs485.flags & SER_RS485_ENABLED) {
2014 if (serial8250_in_MCR(up) & UART_MCR_RTS)
2015 mctrl |= TIOCM_RTS;
2016 else
2017 mctrl &= ~TIOCM_RTS;
2018 }
2019
2020 mcr = serial8250_TIOCM_to_MCR(mctrl);
2021
2022 mcr = (mcr & up->mcr_mask) | up->mcr_force | up->mcr;
2023
2024 serial8250_out_MCR(up, mcr);
2025 }
2026 EXPORT_SYMBOL_GPL(serial8250_do_set_mctrl);
2027
2028 static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
2029 {
2030 if (port->set_mctrl)
2031 port->set_mctrl(port, mctrl);
2032 else
2033 serial8250_do_set_mctrl(port, mctrl);
2034 }
2035
2036 static void serial8250_break_ctl(struct uart_port *port, int break_state)
2037 {
2038 struct uart_8250_port *up = up_to_u8250p(port);
2039 unsigned long flags;
2040
2041 serial8250_rpm_get(up);
2042 spin_lock_irqsave(&port->lock, flags);
2043 if (break_state == -1)
2044 up->lcr |= UART_LCR_SBC;
2045 else
2046 up->lcr &= ~UART_LCR_SBC;
2047 serial_port_out(port, UART_LCR, up->lcr);
2048 spin_unlock_irqrestore(&port->lock, flags);
2049 serial8250_rpm_put(up);
2050 }
2051
2052 /*
2053 * Wait for transmitter & holding register to empty
2054 */
2055 static void wait_for_xmitr(struct uart_8250_port *up, int bits)
2056 {
2057 unsigned int status, tmout = 10000;
2058
2059 /* Wait up to 10ms for the character(s) to be sent. */
2060 for (;;) {
2061 status = serial_in(up, UART_LSR);
2062
2063 up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
2064
2065 if ((status & bits) == bits)
2066 break;
2067 if (--tmout == 0)
2068 break;
2069 udelay(1);
2070 touch_nmi_watchdog();
2071 }
2072
2073 /* Wait up to 1s for flow control if necessary */
2074 if (up->port.flags & UPF_CONS_FLOW) {
2075 for (tmout = 1000000; tmout; tmout--) {
2076 unsigned int msr = serial_in(up, UART_MSR);
2077 up->msr_saved_flags |= msr & MSR_SAVE_FLAGS;
2078 if (msr & UART_MSR_CTS)
2079 break;
2080 udelay(1);
2081 touch_nmi_watchdog();
2082 }
2083 }
2084 }
2085
2086 #ifdef CONFIG_CONSOLE_POLL
2087 /*
2088 * Console polling routines for writing and reading from the uart while
2089 * in an interrupt or debug context.
2090 */
2091
2092 static int serial8250_get_poll_char(struct uart_port *port)
2093 {
2094 struct uart_8250_port *up = up_to_u8250p(port);
2095 unsigned char lsr;
2096 int status;
2097
2098 serial8250_rpm_get(up);
2099
2100 lsr = serial_port_in(port, UART_LSR);
2101
2102 if (!(lsr & UART_LSR_DR)) {
2103 status = NO_POLL_CHAR;
2104 goto out;
2105 }
2106
2107 status = serial_port_in(port, UART_RX);
2108 out:
2109 serial8250_rpm_put(up);
2110 return status;
2111 }
2112
2113
2114 static void serial8250_put_poll_char(struct uart_port *port,
2115 unsigned char c)
2116 {
2117 unsigned int ier;
2118 struct uart_8250_port *up = up_to_u8250p(port);
2119
2120 serial8250_rpm_get(up);
2121 /*
2122 * First save the IER then disable the interrupts
2123 */
2124 ier = serial_port_in(port, UART_IER);
2125 if (up->capabilities & UART_CAP_UUE)
2126 serial_port_out(port, UART_IER, UART_IER_UUE);
2127 else
2128 serial_port_out(port, UART_IER, 0);
2129
2130 wait_for_xmitr(up, BOTH_EMPTY);
2131 /*
2132 * Send the character out.
2133 */
2134 serial_port_out(port, UART_TX, c);
2135
2136 /*
2137 * Finally, wait for transmitter to become empty
2138 * and restore the IER
2139 */
2140 wait_for_xmitr(up, BOTH_EMPTY);
2141 serial_port_out(port, UART_IER, ier);
2142 serial8250_rpm_put(up);
2143 }
2144
2145 #endif /* CONFIG_CONSOLE_POLL */
2146
2147 int serial8250_do_startup(struct uart_port *port)
2148 {
2149 struct uart_8250_port *up = up_to_u8250p(port);
2150 unsigned long flags;
2151 unsigned char lsr, iir;
2152 int retval;
2153
2154 if (!port->fifosize)
2155 port->fifosize = uart_config[port->type].fifo_size;
2156 if (!up->tx_loadsz)
2157 up->tx_loadsz = uart_config[port->type].tx_loadsz;
2158 if (!up->capabilities)
2159 up->capabilities = uart_config[port->type].flags;
2160 up->mcr = 0;
2161
2162 if (port->iotype != up->cur_iotype)
2163 set_io_from_upio(port);
2164
2165 serial8250_rpm_get(up);
2166 if (port->type == PORT_16C950) {
2167 /* Wake up and initialize UART */
2168 up->acr = 0;
2169 serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
2170 serial_port_out(port, UART_EFR, UART_EFR_ECB);
2171 serial_port_out(port, UART_IER, 0);
2172 serial_port_out(port, UART_LCR, 0);
2173 serial_icr_write(up, UART_CSR, 0); /* Reset the UART */
2174 serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
2175 serial_port_out(port, UART_EFR, UART_EFR_ECB);
2176 serial_port_out(port, UART_LCR, 0);
2177 }
2178
2179 if (port->type == PORT_DA830) {
2180 /* Reset the port */
2181 serial_port_out(port, UART_IER, 0);
2182 serial_port_out(port, UART_DA830_PWREMU_MGMT, 0);
2183 mdelay(10);
2184
2185 /* Enable Tx, Rx and free run mode */
2186 serial_port_out(port, UART_DA830_PWREMU_MGMT,
2187 UART_DA830_PWREMU_MGMT_UTRST |
2188 UART_DA830_PWREMU_MGMT_URRST |
2189 UART_DA830_PWREMU_MGMT_FREE);
2190 }
2191
2192 if (port->type == PORT_NPCM) {
2193 /*
2194 * Nuvoton calls the scratch register 'UART_TOR' (timeout
2195 * register). Enable it, and set TIOC (timeout interrupt
2196 * comparator) to be 0x20 for correct operation.
2197 */
2198 serial_port_out(port, UART_NPCM_TOR, UART_NPCM_TOIE | 0x20);
2199 }
2200
2201 #ifdef CONFIG_SERIAL_8250_RSA
2202 /*
2203 * If this is an RSA port, see if we can kick it up to the
2204 * higher speed clock.
2205 */
2206 enable_rsa(up);
2207 #endif
2208
2209 /*
2210 * Clear the FIFO buffers and disable them.
2211 * (they will be reenabled in set_termios())
2212 */
2213 serial8250_clear_fifos(up);
2214
2215 /*
2216 * Clear the interrupt registers.
2217 */
2218 serial_port_in(port, UART_LSR);
2219 serial_port_in(port, UART_RX);
2220 serial_port_in(port, UART_IIR);
2221 serial_port_in(port, UART_MSR);
2222
2223 /*
2224 * At this point, there's no way the LSR could still be 0xff;
2225 * if it is, then bail out, because there's likely no UART
2226 * here.
2227 */
2228 if (!(port->flags & UPF_BUGGY_UART) &&
2229 (serial_port_in(port, UART_LSR) == 0xff)) {
2230 dev_info_ratelimited(port->dev, "LSR safety check engaged!\n");
2231 retval = -ENODEV;
2232 goto out;
2233 }
2234
2235 /*
2236 * For a XR16C850, we need to set the trigger levels
2237 */
2238 if (port->type == PORT_16850) {
2239 unsigned char fctr;
2240
2241 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
2242
2243 fctr = serial_in(up, UART_FCTR) & ~(UART_FCTR_RX|UART_FCTR_TX);
2244 serial_port_out(port, UART_FCTR,
2245 fctr | UART_FCTR_TRGD | UART_FCTR_RX);
2246 serial_port_out(port, UART_TRG, UART_TRG_96);
2247 serial_port_out(port, UART_FCTR,
2248 fctr | UART_FCTR_TRGD | UART_FCTR_TX);
2249 serial_port_out(port, UART_TRG, UART_TRG_96);
2250
2251 serial_port_out(port, UART_LCR, 0);
2252 }
2253
2254 /*
2255 * For the Altera 16550 variants, set TX threshold trigger level.
2256 */
2257 if (((port->type == PORT_ALTR_16550_F32) ||
2258 (port->type == PORT_ALTR_16550_F64) ||
2259 (port->type == PORT_ALTR_16550_F128)) && (port->fifosize > 1)) {
2260 /* Bounds checking of TX threshold (valid 0 to fifosize-2) */
2261 if ((up->tx_loadsz < 2) || (up->tx_loadsz > port->fifosize)) {
2262 dev_err(port->dev, "TX FIFO Threshold errors, skipping\n");
2263 } else {
2264 serial_port_out(port, UART_ALTR_AFR,
2265 UART_ALTR_EN_TXFIFO_LW);
2266 serial_port_out(port, UART_ALTR_TX_LOW,
2267 port->fifosize - up->tx_loadsz);
2268 port->handle_irq = serial8250_tx_threshold_handle_irq;
2269 }
2270 }
2271
2272 /* Check if we need to have shared IRQs */
2273 if (port->irq && (up->port.flags & UPF_SHARE_IRQ))
2274 up->port.irqflags |= IRQF_SHARED;
2275
2276 if (port->irq && !(up->port.flags & UPF_NO_THRE_TEST)) {
2277 unsigned char iir1;
2278
2279 if (port->irqflags & IRQF_SHARED)
2280 disable_irq_nosync(port->irq);
2281
2282 /*
2283 * Test for UARTs that do not reassert THRE when the
2284 * transmitter is idle and the interrupt has already
2285 * been cleared. Real 16550s should always reassert
2286 * this interrupt whenever the transmitter is idle and
2287 * the interrupt is enabled. Delays are necessary to
2288 * allow register changes to become visible.
2289 */
2290 spin_lock_irqsave(&port->lock, flags);
2291
2292 wait_for_xmitr(up, UART_LSR_THRE);
2293 serial_port_out_sync(port, UART_IER, UART_IER_THRI);
2294 udelay(1); /* allow THRE to set */
2295 iir1 = serial_port_in(port, UART_IIR);
2296 serial_port_out(port, UART_IER, 0);
2297 serial_port_out_sync(port, UART_IER, UART_IER_THRI);
2298 udelay(1); /* allow a working UART time to re-assert THRE */
2299 iir = serial_port_in(port, UART_IIR);
2300 serial_port_out(port, UART_IER, 0);
2301
2302 spin_unlock_irqrestore(&port->lock, flags);
2303
2304 if (port->irqflags & IRQF_SHARED)
2305 enable_irq(port->irq);
2306
2307 /*
2308 * If the interrupt is not reasserted, or we otherwise
2309 * don't trust the iir, setup a timer to kick the UART
2310 * on a regular basis.
2311 */
2312 if ((!(iir1 & UART_IIR_NO_INT) && (iir & UART_IIR_NO_INT)) ||
2313 up->port.flags & UPF_BUG_THRE) {
2314 up->bugs |= UART_BUG_THRE;
2315 }
2316 }
2317
2318 retval = up->ops->setup_irq(up);
2319 if (retval)
2320 goto out;
2321
2322 /*
2323 * Now, initialize the UART
2324 */
2325 serial_port_out(port, UART_LCR, UART_LCR_WLEN8);
2326
2327 spin_lock_irqsave(&port->lock, flags);
2328 if (up->port.flags & UPF_FOURPORT) {
2329 if (!up->port.irq)
2330 up->port.mctrl |= TIOCM_OUT1;
2331 } else
2332 /*
2333 * Most PC uarts need OUT2 raised to enable interrupts.
2334 */
2335 if (port->irq)
2336 up->port.mctrl |= TIOCM_OUT2;
2337
2338 serial8250_set_mctrl(port, port->mctrl);
2339
2340 /*
2341 * Serial over Lan (SoL) hack:
2342 * Intel 8257x Gigabit ethernet chips have a 16550 emulation, to be
2343 * used for Serial Over Lan. Those chips take a longer time than a
2344 * normal serial device to signalize that a transmission data was
2345 * queued. Due to that, the above test generally fails. One solution
2346 * would be to delay the reading of iir. However, this is not
2347 * reliable, since the timeout is variable. So, let's just don't
2348 * test if we receive TX irq. This way, we'll never enable
2349 * UART_BUG_TXEN.
2350 */
2351 if (up->port.quirks & UPQ_NO_TXEN_TEST)
2352 goto dont_test_tx_en;
2353
2354 /*
2355 * Do a quick test to see if we receive an interrupt when we enable
2356 * the TX irq.
2357 */
2358 serial_port_out(port, UART_IER, UART_IER_THRI);
2359 lsr = serial_port_in(port, UART_LSR);
2360 iir = serial_port_in(port, UART_IIR);
2361 serial_port_out(port, UART_IER, 0);
2362
2363 if (lsr & UART_LSR_TEMT && iir & UART_IIR_NO_INT) {
2364 if (!(up->bugs & UART_BUG_TXEN)) {
2365 up->bugs |= UART_BUG_TXEN;
2366 dev_dbg(port->dev, "enabling bad tx status workarounds\n");
2367 }
2368 } else {
2369 up->bugs &= ~UART_BUG_TXEN;
2370 }
2371
2372 dont_test_tx_en:
2373 spin_unlock_irqrestore(&port->lock, flags);
2374
2375 /*
2376 * Clear the interrupt registers again for luck, and clear the
2377 * saved flags to avoid getting false values from polling
2378 * routines or the previous session.
2379 */
2380 serial_port_in(port, UART_LSR);
2381 serial_port_in(port, UART_RX);
2382 serial_port_in(port, UART_IIR);
2383 serial_port_in(port, UART_MSR);
2384 up->lsr_saved_flags = 0;
2385 up->msr_saved_flags = 0;
2386
2387 /*
2388 * Request DMA channels for both RX and TX.
2389 */
2390 if (up->dma) {
2391 const char *msg = NULL;
2392
2393 if (uart_console(port))
2394 msg = "forbid DMA for kernel console";
2395 else if (serial8250_request_dma(up))
2396 msg = "failed to request DMA";
2397 if (msg) {
2398 dev_warn_ratelimited(port->dev, "%s\n", msg);
2399 up->dma = NULL;
2400 }
2401 }
2402
2403 /*
2404 * Set the IER shadow for rx interrupts but defer actual interrupt
2405 * enable until after the FIFOs are enabled; otherwise, an already-
2406 * active sender can swamp the interrupt handler with "too much work".
2407 */
2408 up->ier = UART_IER_RLSI | UART_IER_RDI;
2409
2410 if (port->flags & UPF_FOURPORT) {
2411 unsigned int icp;
2412 /*
2413 * Enable interrupts on the AST Fourport board
2414 */
2415 icp = (port->iobase & 0xfe0) | 0x01f;
2416 outb_p(0x80, icp);
2417 inb_p(icp);
2418 }
2419 retval = 0;
2420 out:
2421 serial8250_rpm_put(up);
2422 return retval;
2423 }
2424 EXPORT_SYMBOL_GPL(serial8250_do_startup);
2425
2426 static int serial8250_startup(struct uart_port *port)
2427 {
2428 if (port->startup)
2429 return port->startup(port);
2430 return serial8250_do_startup(port);
2431 }
2432
2433 void serial8250_do_shutdown(struct uart_port *port)
2434 {
2435 struct uart_8250_port *up = up_to_u8250p(port);
2436 unsigned long flags;
2437
2438 serial8250_rpm_get(up);
2439 /*
2440 * Disable interrupts from this port
2441 */
2442 spin_lock_irqsave(&port->lock, flags);
2443 up->ier = 0;
2444 serial_port_out(port, UART_IER, 0);
2445 spin_unlock_irqrestore(&port->lock, flags);
2446
2447 synchronize_irq(port->irq);
2448
2449 if (up->dma)
2450 serial8250_release_dma(up);
2451
2452 spin_lock_irqsave(&port->lock, flags);
2453 if (port->flags & UPF_FOURPORT) {
2454 /* reset interrupts on the AST Fourport board */
2455 inb((port->iobase & 0xfe0) | 0x1f);
2456 port->mctrl |= TIOCM_OUT1;
2457 } else
2458 port->mctrl &= ~TIOCM_OUT2;
2459
2460 serial8250_set_mctrl(port, port->mctrl);
2461 spin_unlock_irqrestore(&port->lock, flags);
2462
2463 /*
2464 * Disable break condition and FIFOs
2465 */
2466 serial_port_out(port, UART_LCR,
2467 serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
2468 serial8250_clear_fifos(up);
2469
2470 #ifdef CONFIG_SERIAL_8250_RSA
2471 /*
2472 * Reset the RSA board back to 115kbps compat mode.
2473 */
2474 disable_rsa(up);
2475 #endif
2476
2477 /*
2478 * Read data port to reset things, and then unlink from
2479 * the IRQ chain.
2480 */
2481 serial_port_in(port, UART_RX);
2482 serial8250_rpm_put(up);
2483
2484 up->ops->release_irq(up);
2485 }
2486 EXPORT_SYMBOL_GPL(serial8250_do_shutdown);
2487
2488 static void serial8250_shutdown(struct uart_port *port)
2489 {
2490 if (port->shutdown)
2491 port->shutdown(port);
2492 else
2493 serial8250_do_shutdown(port);
2494 }
2495
2496 /* Nuvoton NPCM UARTs have a custom divisor calculation */
2497 static unsigned int npcm_get_divisor(struct uart_8250_port *up,
2498 unsigned int baud)
2499 {
2500 struct uart_port *port = &up->port;
2501
2502 return DIV_ROUND_CLOSEST(port->uartclk, 16 * baud + 2) - 2;
2503 }
2504
2505 static unsigned int serial8250_do_get_divisor(struct uart_port *port,
2506 unsigned int baud,
2507 unsigned int *frac)
2508 {
2509 struct uart_8250_port *up = up_to_u8250p(port);
2510 unsigned int quot;
2511
2512 /*
2513 * Handle magic divisors for baud rates above baud_base on
2514 * SMSC SuperIO chips.
2515 *
2516 */
2517 if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
2518 baud == (port->uartclk/4))
2519 quot = 0x8001;
2520 else if ((port->flags & UPF_MAGIC_MULTIPLIER) &&
2521 baud == (port->uartclk/8))
2522 quot = 0x8002;
2523 else if (up->port.type == PORT_NPCM)
2524 quot = npcm_get_divisor(up, baud);
2525 else
2526 quot = uart_get_divisor(port, baud);
2527
2528 /*
2529 * Oxford Semi 952 rev B workaround
2530 */
2531 if (up->bugs & UART_BUG_QUOT && (quot & 0xff) == 0)
2532 quot++;
2533
2534 return quot;
2535 }
2536
2537 static unsigned int serial8250_get_divisor(struct uart_port *port,
2538 unsigned int baud,
2539 unsigned int *frac)
2540 {
2541 if (port->get_divisor)
2542 return port->get_divisor(port, baud, frac);
2543
2544 return serial8250_do_get_divisor(port, baud, frac);
2545 }
2546
2547 static unsigned char serial8250_compute_lcr(struct uart_8250_port *up,
2548 tcflag_t c_cflag)
2549 {
2550 unsigned char cval;
2551
2552 switch (c_cflag & CSIZE) {
2553 case CS5:
2554 cval = UART_LCR_WLEN5;
2555 break;
2556 case CS6:
2557 cval = UART_LCR_WLEN6;
2558 break;
2559 case CS7:
2560 cval = UART_LCR_WLEN7;
2561 break;
2562 default:
2563 case CS8:
2564 cval = UART_LCR_WLEN8;
2565 break;
2566 }
2567
2568 if (c_cflag & CSTOPB)
2569 cval |= UART_LCR_STOP;
2570 if (c_cflag & PARENB) {
2571 cval |= UART_LCR_PARITY;
2572 if (up->bugs & UART_BUG_PARITY)
2573 up->fifo_bug = true;
2574 }
2575 if (!(c_cflag & PARODD))
2576 cval |= UART_LCR_EPAR;
2577 #ifdef CMSPAR
2578 if (c_cflag & CMSPAR)
2579 cval |= UART_LCR_SPAR;
2580 #endif
2581
2582 return cval;
2583 }
2584
2585 void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
2586 unsigned int quot, unsigned int quot_frac)
2587 {
2588 struct uart_8250_port *up = up_to_u8250p(port);
2589
2590 /* Workaround to enable 115200 baud on OMAP1510 internal ports */
2591 if (is_omap1510_8250(up)) {
2592 if (baud == 115200) {
2593 quot = 1;
2594 serial_port_out(port, UART_OMAP_OSC_12M_SEL, 1);
2595 } else
2596 serial_port_out(port, UART_OMAP_OSC_12M_SEL, 0);
2597 }
2598
2599 /*
2600 * For NatSemi, switch to bank 2 not bank 1, to avoid resetting EXCR2,
2601 * otherwise just set DLAB
2602 */
2603 if (up->capabilities & UART_NATSEMI)
2604 serial_port_out(port, UART_LCR, 0xe0);
2605 else
2606 serial_port_out(port, UART_LCR, up->lcr | UART_LCR_DLAB);
2607
2608 serial_dl_write(up, quot);
2609 }
2610 EXPORT_SYMBOL_GPL(serial8250_do_set_divisor);
2611
2612 static void serial8250_set_divisor(struct uart_port *port, unsigned int baud,
2613 unsigned int quot, unsigned int quot_frac)
2614 {
2615 if (port->set_divisor)
2616 port->set_divisor(port, baud, quot, quot_frac);
2617 else
2618 serial8250_do_set_divisor(port, baud, quot, quot_frac);
2619 }
2620
2621 static unsigned int serial8250_get_baud_rate(struct uart_port *port,
2622 struct ktermios *termios,
2623 struct ktermios *old)
2624 {
2625 unsigned int tolerance = port->uartclk / 100;
2626
2627 /*
2628 * Ask the core to calculate the divisor for us.
2629 * Allow 1% tolerance at the upper limit so uart clks marginally
2630 * slower than nominal still match standard baud rates without
2631 * causing transmission errors.
2632 */
2633 return uart_get_baud_rate(port, termios, old,
2634 port->uartclk / 16 / UART_DIV_MAX,
2635 (port->uartclk + tolerance) / 16);
2636 }
2637
2638 /*
2639 * Note in order to avoid the tty port mutex deadlock don't use the next method
2640 * within the uart port callbacks. Primarily it's supposed to be utilized to
2641 * handle a sudden reference clock rate change.
2642 */
2643 void serial8250_update_uartclk(struct uart_port *port, unsigned int uartclk)
2644 {
2645 struct uart_8250_port *up = up_to_u8250p(port);
2646 unsigned int baud, quot, frac = 0;
2647 struct ktermios *termios;
2648 unsigned long flags;
2649
2650 mutex_lock(&port->state->port.mutex);
2651
2652 if (port->uartclk == uartclk)
2653 goto out_lock;
2654
2655 port->uartclk = uartclk;
2656
2657 if (!tty_port_initialized(&port->state->port))
2658 goto out_lock;
2659
2660 termios = &port->state->port.tty->termios;
2661
2662 baud = serial8250_get_baud_rate(port, termios, NULL);
2663 quot = serial8250_get_divisor(port, baud, &frac);
2664
2665 serial8250_rpm_get(up);
2666 spin_lock_irqsave(&port->lock, flags);
2667
2668 uart_update_timeout(port, termios->c_cflag, baud);
2669
2670 serial8250_set_divisor(port, baud, quot, frac);
2671 serial_port_out(port, UART_LCR, up->lcr);
2672
2673 spin_unlock_irqrestore(&port->lock, flags);
2674 serial8250_rpm_put(up);
2675
2676 out_lock:
2677 mutex_unlock(&port->state->port.mutex);
2678 }
2679 EXPORT_SYMBOL_GPL(serial8250_update_uartclk);
2680
2681 void
2682 serial8250_do_set_termios(struct uart_port *port, struct ktermios *termios,
2683 struct ktermios *old)
2684 {
2685 struct uart_8250_port *up = up_to_u8250p(port);
2686 unsigned char cval;
2687 unsigned long flags;
2688 unsigned int baud, quot, frac = 0;
2689
2690 if (up->capabilities & UART_CAP_MINI) {
2691 termios->c_cflag &= ~(CSTOPB | PARENB | PARODD | CMSPAR);
2692 if ((termios->c_cflag & CSIZE) == CS5 ||
2693 (termios->c_cflag & CSIZE) == CS6)
2694 termios->c_cflag = (termios->c_cflag & ~CSIZE) | CS7;
2695 }
2696 cval = serial8250_compute_lcr(up, termios->c_cflag);
2697
2698 baud = serial8250_get_baud_rate(port, termios, old);
2699 quot = serial8250_get_divisor(port, baud, &frac);
2700
2701 /*
2702 * Ok, we're now changing the port state. Do it with
2703 * interrupts disabled.
2704 */
2705 serial8250_rpm_get(up);
2706 spin_lock_irqsave(&port->lock, flags);
2707
2708 up->lcr = cval; /* Save computed LCR */
2709
2710 if (up->capabilities & UART_CAP_FIFO && port->fifosize > 1) {
2711 /* NOTE: If fifo_bug is not set, a user can set RX_trigger. */
2712 if ((baud < 2400 && !up->dma) || up->fifo_bug) {
2713 up->fcr &= ~UART_FCR_TRIGGER_MASK;
2714 up->fcr |= UART_FCR_TRIGGER_1;
2715 }
2716 }
2717
2718 /*
2719 * MCR-based auto flow control. When AFE is enabled, RTS will be
2720 * deasserted when the receive FIFO contains more characters than
2721 * the trigger, or the MCR RTS bit is cleared.
2722 */
2723 if (up->capabilities & UART_CAP_AFE) {
2724 up->mcr &= ~UART_MCR_AFE;
2725 if (termios->c_cflag & CRTSCTS)
2726 up->mcr |= UART_MCR_AFE;
2727 }
2728
2729 /*
2730 * Update the per-port timeout.
2731 */
2732 uart_update_timeout(port, termios->c_cflag, baud);
2733
2734 port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
2735 if (termios->c_iflag & INPCK)
2736 port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
2737 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
2738 port->read_status_mask |= UART_LSR_BI;
2739
2740 /*
2741 * Characteres to ignore
2742 */
2743 port->ignore_status_mask = 0;
2744 if (termios->c_iflag & IGNPAR)
2745 port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
2746 if (termios->c_iflag & IGNBRK) {
2747 port->ignore_status_mask |= UART_LSR_BI;
2748 /*
2749 * If we're ignoring parity and break indicators,
2750 * ignore overruns too (for real raw support).
2751 */
2752 if (termios->c_iflag & IGNPAR)
2753 port->ignore_status_mask |= UART_LSR_OE;
2754 }
2755
2756 /*
2757 * ignore all characters if CREAD is not set
2758 */
2759 if ((termios->c_cflag & CREAD) == 0)
2760 port->ignore_status_mask |= UART_LSR_DR;
2761
2762 /*
2763 * CTS flow control flag and modem status interrupts
2764 */
2765 up->ier &= ~UART_IER_MSI;
2766 if (!(up->bugs & UART_BUG_NOMSR) &&
2767 UART_ENABLE_MS(&up->port, termios->c_cflag))
2768 up->ier |= UART_IER_MSI;
2769 if (up->capabilities & UART_CAP_UUE)
2770 up->ier |= UART_IER_UUE;
2771 if (up->capabilities & UART_CAP_RTOIE)
2772 up->ier |= UART_IER_RTOIE;
2773
2774 serial_port_out(port, UART_IER, up->ier);
2775
2776 if (up->capabilities & UART_CAP_EFR) {
2777 unsigned char efr = 0;
2778 /*
2779 * TI16C752/Startech hardware flow control. FIXME:
2780 * - TI16C752 requires control thresholds to be set.
2781 * - UART_MCR_RTS is ineffective if auto-RTS mode is enabled.
2782 */
2783 if (termios->c_cflag & CRTSCTS)
2784 efr |= UART_EFR_CTS;
2785
2786 serial_port_out(port, UART_LCR, UART_LCR_CONF_MODE_B);
2787 if (port->flags & UPF_EXAR_EFR)
2788 serial_port_out(port, UART_XR_EFR, efr);
2789 else
2790 serial_port_out(port, UART_EFR, efr);
2791 }
2792
2793 serial8250_set_divisor(port, baud, quot, frac);
2794
2795 /*
2796 * LCR DLAB must be set to enable 64-byte FIFO mode. If the FCR
2797 * is written without DLAB set, this mode will be disabled.
2798 */
2799 if (port->type == PORT_16750)
2800 serial_port_out(port, UART_FCR, up->fcr);
2801
2802 serial_port_out(port, UART_LCR, up->lcr); /* reset DLAB */
2803 if (port->type != PORT_16750) {
2804 /* emulated UARTs (Lucent Venus 167x) need two steps */
2805 if (up->fcr & UART_FCR_ENABLE_FIFO)
2806 serial_port_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
2807 serial_port_out(port, UART_FCR, up->fcr); /* set fcr */
2808 }
2809 serial8250_set_mctrl(port, port->mctrl);
2810 spin_unlock_irqrestore(&port->lock, flags);
2811 serial8250_rpm_put(up);
2812
2813 /* Don't rewrite B0 */
2814 if (tty_termios_baud_rate(termios))
2815 tty_termios_encode_baud_rate(termios, baud, baud);
2816 }
2817 EXPORT_SYMBOL(serial8250_do_set_termios);
2818
2819 static void
2820 serial8250_set_termios(struct uart_port *port, struct ktermios *termios,
2821 struct ktermios *old)
2822 {
2823 if (port->set_termios)
2824 port->set_termios(port, termios, old);
2825 else
2826 serial8250_do_set_termios(port, termios, old);
2827 }
2828
2829 void serial8250_do_set_ldisc(struct uart_port *port, struct ktermios *termios)
2830 {
2831 if (termios->c_line == N_PPS) {
2832 port->flags |= UPF_HARDPPS_CD;
2833 spin_lock_irq(&port->lock);
2834 serial8250_enable_ms(port);
2835 spin_unlock_irq(&port->lock);
2836 } else {
2837 port->flags &= ~UPF_HARDPPS_CD;
2838 if (!UART_ENABLE_MS(port, termios->c_cflag)) {
2839 spin_lock_irq(&port->lock);
2840 serial8250_disable_ms(port);
2841 spin_unlock_irq(&port->lock);
2842 }
2843 }
2844 }
2845 EXPORT_SYMBOL_GPL(serial8250_do_set_ldisc);
2846
2847 static void
2848 serial8250_set_ldisc(struct uart_port *port, struct ktermios *termios)
2849 {
2850 if (port->set_ldisc)
2851 port->set_ldisc(port, termios);
2852 else
2853 serial8250_do_set_ldisc(port, termios);
2854 }
2855
2856 void serial8250_do_pm(struct uart_port *port, unsigned int state,
2857 unsigned int oldstate)
2858 {
2859 struct uart_8250_port *p = up_to_u8250p(port);
2860
2861 serial8250_set_sleep(p, state != 0);
2862 }
2863 EXPORT_SYMBOL(serial8250_do_pm);
2864
2865 static void
2866 serial8250_pm(struct uart_port *port, unsigned int state,
2867 unsigned int oldstate)
2868 {
2869 if (port->pm)
2870 port->pm(port, state, oldstate);
2871 else
2872 serial8250_do_pm(port, state, oldstate);
2873 }
2874
2875 static unsigned int serial8250_port_size(struct uart_8250_port *pt)
2876 {
2877 if (pt->port.mapsize)
2878 return pt->port.mapsize;
2879 if (pt->port.iotype == UPIO_AU) {
2880 if (pt->port.type == PORT_RT2880)
2881 return 0x100;
2882 return 0x1000;
2883 }
2884 if (is_omap1_8250(pt))
2885 return 0x16 << pt->port.regshift;
2886
2887 return 8 << pt->port.regshift;
2888 }
2889
2890 /*
2891 * Resource handling.
2892 */
2893 static int serial8250_request_std_resource(struct uart_8250_port *up)
2894 {
2895 unsigned int size = serial8250_port_size(up);
2896 struct uart_port *port = &up->port;
2897 int ret = 0;
2898
2899 switch (port->iotype) {
2900 case UPIO_AU:
2901 case UPIO_TSI:
2902 case UPIO_MEM32:
2903 case UPIO_MEM32BE:
2904 case UPIO_MEM16:
2905 case UPIO_MEM:
2906 if (!port->mapbase)
2907 break;
2908
2909 if (!request_mem_region(port->mapbase, size, "serial")) {
2910 ret = -EBUSY;
2911 break;
2912 }
2913
2914 if (port->flags & UPF_IOREMAP) {
2915 port->membase = ioremap(port->mapbase, size);
2916 if (!port->membase) {
2917 release_mem_region(port->mapbase, size);
2918 ret = -ENOMEM;
2919 }
2920 }
2921 break;
2922
2923 case UPIO_HUB6:
2924 case UPIO_PORT:
2925 if (!request_region(port->iobase, size, "serial"))
2926 ret = -EBUSY;
2927 break;
2928 }
2929 return ret;
2930 }
2931
2932 static void serial8250_release_std_resource(struct uart_8250_port *up)
2933 {
2934 unsigned int size = serial8250_port_size(up);
2935 struct uart_port *port = &up->port;
2936
2937 switch (port->iotype) {
2938 case UPIO_AU:
2939 case UPIO_TSI:
2940 case UPIO_MEM32:
2941 case UPIO_MEM32BE:
2942 case UPIO_MEM16:
2943 case UPIO_MEM:
2944 if (!port->mapbase)
2945 break;
2946
2947 if (port->flags & UPF_IOREMAP) {
2948 iounmap(port->membase);
2949 port->membase = NULL;
2950 }
2951
2952 release_mem_region(port->mapbase, size);
2953 break;
2954
2955 case UPIO_HUB6:
2956 case UPIO_PORT:
2957 release_region(port->iobase, size);
2958 break;
2959 }
2960 }
2961
2962 static void serial8250_release_port(struct uart_port *port)
2963 {
2964 struct uart_8250_port *up = up_to_u8250p(port);
2965
2966 serial8250_release_std_resource(up);
2967 }
2968
2969 static int serial8250_request_port(struct uart_port *port)
2970 {
2971 struct uart_8250_port *up = up_to_u8250p(port);
2972
2973 return serial8250_request_std_resource(up);
2974 }
2975
2976 static int fcr_get_rxtrig_bytes(struct uart_8250_port *up)
2977 {
2978 const struct serial8250_config *conf_type = &uart_config[up->port.type];
2979 unsigned char bytes;
2980
2981 bytes = conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(up->fcr)];
2982
2983 return bytes ? bytes : -EOPNOTSUPP;
2984 }
2985
2986 static int bytes_to_fcr_rxtrig(struct uart_8250_port *up, unsigned char bytes)
2987 {
2988 const struct serial8250_config *conf_type = &uart_config[up->port.type];
2989 int i;
2990
2991 if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])
2992 return -EOPNOTSUPP;
2993
2994 for (i = 1; i < UART_FCR_R_TRIG_MAX_STATE; i++) {
2995 if (bytes < conf_type->rxtrig_bytes[i])
2996 /* Use the nearest lower value */
2997 return (--i) << UART_FCR_R_TRIG_SHIFT;
2998 }
2999
3000 return UART_FCR_R_TRIG_11;
3001 }
3002
3003 static int do_get_rxtrig(struct tty_port *port)
3004 {
3005 struct uart_state *state = container_of(port, struct uart_state, port);
3006 struct uart_port *uport = state->uart_port;
3007 struct uart_8250_port *up = up_to_u8250p(uport);
3008
3009 if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1)
3010 return -EINVAL;
3011
3012 return fcr_get_rxtrig_bytes(up);
3013 }
3014
3015 static int do_serial8250_get_rxtrig(struct tty_port *port)
3016 {
3017 int rxtrig_bytes;
3018
3019 mutex_lock(&port->mutex);
3020 rxtrig_bytes = do_get_rxtrig(port);
3021 mutex_unlock(&port->mutex);
3022
3023 return rxtrig_bytes;
3024 }
3025
3026 static ssize_t rx_trig_bytes_show(struct device *dev,
3027 struct device_attribute *attr, char *buf)
3028 {
3029 struct tty_port *port = dev_get_drvdata(dev);
3030 int rxtrig_bytes;
3031
3032 rxtrig_bytes = do_serial8250_get_rxtrig(port);
3033 if (rxtrig_bytes < 0)
3034 return rxtrig_bytes;
3035
3036 return snprintf(buf, PAGE_SIZE, "%d\n", rxtrig_bytes);
3037 }
3038
3039 static int do_set_rxtrig(struct tty_port *port, unsigned char bytes)
3040 {
3041 struct uart_state *state = container_of(port, struct uart_state, port);
3042 struct uart_port *uport = state->uart_port;
3043 struct uart_8250_port *up = up_to_u8250p(uport);
3044 int rxtrig;
3045
3046 if (!(up->capabilities & UART_CAP_FIFO) || uport->fifosize <= 1 ||
3047 up->fifo_bug)
3048 return -EINVAL;
3049
3050 rxtrig = bytes_to_fcr_rxtrig(up, bytes);
3051 if (rxtrig < 0)
3052 return rxtrig;
3053
3054 serial8250_clear_fifos(up);
3055 up->fcr &= ~UART_FCR_TRIGGER_MASK;
3056 up->fcr |= (unsigned char)rxtrig;
3057 serial_out(up, UART_FCR, up->fcr);
3058 return 0;
3059 }
3060
3061 static int do_serial8250_set_rxtrig(struct tty_port *port, unsigned char bytes)
3062 {
3063 int ret;
3064
3065 mutex_lock(&port->mutex);
3066 ret = do_set_rxtrig(port, bytes);
3067 mutex_unlock(&port->mutex);
3068
3069 return ret;
3070 }
3071
3072 static ssize_t rx_trig_bytes_store(struct device *dev,
3073 struct device_attribute *attr, const char *buf, size_t count)
3074 {
3075 struct tty_port *port = dev_get_drvdata(dev);
3076 unsigned char bytes;
3077 int ret;
3078
3079 if (!count)
3080 return -EINVAL;
3081
3082 ret = kstrtou8(buf, 10, &bytes);
3083 if (ret < 0)
3084 return ret;
3085
3086 ret = do_serial8250_set_rxtrig(port, bytes);
3087 if (ret < 0)
3088 return ret;
3089
3090 return count;
3091 }
3092
3093 static DEVICE_ATTR_RW(rx_trig_bytes);
3094
3095 static struct attribute *serial8250_dev_attrs[] = {
3096 &dev_attr_rx_trig_bytes.attr,
3097 NULL
3098 };
3099
3100 static struct attribute_group serial8250_dev_attr_group = {
3101 .attrs = serial8250_dev_attrs,
3102 };
3103
3104 static void register_dev_spec_attr_grp(struct uart_8250_port *up)
3105 {
3106 const struct serial8250_config *conf_type = &uart_config[up->port.type];
3107
3108 if (conf_type->rxtrig_bytes[0])
3109 up->port.attr_group = &serial8250_dev_attr_group;
3110 }
3111
3112 static void serial8250_config_port(struct uart_port *port, int flags)
3113 {
3114 struct uart_8250_port *up = up_to_u8250p(port);
3115 int ret;
3116
3117 /*
3118 * Find the region that we can probe for. This in turn
3119 * tells us whether we can probe for the type of port.
3120 */
3121 ret = serial8250_request_std_resource(up);
3122 if (ret < 0)
3123 return;
3124
3125 if (port->iotype != up->cur_iotype)
3126 set_io_from_upio(port);
3127
3128 if (flags & UART_CONFIG_TYPE)
3129 autoconfig(up);
3130
3131 if (port->rs485.flags & SER_RS485_ENABLED)
3132 port->rs485_config(port, &port->rs485);
3133
3134 /* if access method is AU, it is a 16550 with a quirk */
3135 if (port->type == PORT_16550A && port->iotype == UPIO_AU)
3136 up->bugs |= UART_BUG_NOMSR;
3137
3138 /* HW bugs may trigger IRQ while IIR == NO_INT */
3139 if (port->type == PORT_TEGRA)
3140 up->bugs |= UART_BUG_NOMSR;
3141
3142 if (port->type != PORT_UNKNOWN && flags & UART_CONFIG_IRQ)
3143 autoconfig_irq(up);
3144
3145 if (port->type == PORT_UNKNOWN)
3146 serial8250_release_std_resource(up);
3147
3148 register_dev_spec_attr_grp(up);
3149 up->fcr = uart_config[up->port.type].fcr;
3150 }
3151
3152 static int
3153 serial8250_verify_port(struct uart_port *port, struct serial_struct *ser)
3154 {
3155 if (ser->irq >= nr_irqs || ser->irq < 0 ||
3156 ser->baud_base < 9600 || ser->type < PORT_UNKNOWN ||
3157 ser->type >= ARRAY_SIZE(uart_config) || ser->type == PORT_CIRRUS ||
3158 ser->type == PORT_STARTECH)
3159 return -EINVAL;
3160 return 0;
3161 }
3162
3163 static const char *serial8250_type(struct uart_port *port)
3164 {
3165 int type = port->type;
3166
3167 if (type >= ARRAY_SIZE(uart_config))
3168 type = 0;
3169 return uart_config[type].name;
3170 }
3171
3172 static const struct uart_ops serial8250_pops = {
3173 .tx_empty = serial8250_tx_empty,
3174 .set_mctrl = serial8250_set_mctrl,
3175 .get_mctrl = serial8250_get_mctrl,
3176 .stop_tx = serial8250_stop_tx,
3177 .start_tx = serial8250_start_tx,
3178 .throttle = serial8250_throttle,
3179 .unthrottle = serial8250_unthrottle,
3180 .stop_rx = serial8250_stop_rx,
3181 .enable_ms = serial8250_enable_ms,
3182 .break_ctl = serial8250_break_ctl,
3183 .startup = serial8250_startup,
3184 .shutdown = serial8250_shutdown,
3185 .set_termios = serial8250_set_termios,
3186 .set_ldisc = serial8250_set_ldisc,
3187 .pm = serial8250_pm,
3188 .type = serial8250_type,
3189 .release_port = serial8250_release_port,
3190 .request_port = serial8250_request_port,
3191 .config_port = serial8250_config_port,
3192 .verify_port = serial8250_verify_port,
3193 #ifdef CONFIG_CONSOLE_POLL
3194 .poll_get_char = serial8250_get_poll_char,
3195 .poll_put_char = serial8250_put_poll_char,
3196 #endif
3197 };
3198
3199 void serial8250_init_port(struct uart_8250_port *up)
3200 {
3201 struct uart_port *port = &up->port;
3202
3203 spin_lock_init(&port->lock);
3204 port->ops = &serial8250_pops;
3205 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
3206
3207 up->cur_iotype = 0xFF;
3208 }
3209 EXPORT_SYMBOL_GPL(serial8250_init_port);
3210
3211 void serial8250_set_defaults(struct uart_8250_port *up)
3212 {
3213 struct uart_port *port = &up->port;
3214
3215 if (up->port.flags & UPF_FIXED_TYPE) {
3216 unsigned int type = up->port.type;
3217
3218 if (!up->port.fifosize)
3219 up->port.fifosize = uart_config[type].fifo_size;
3220 if (!up->tx_loadsz)
3221 up->tx_loadsz = uart_config[type].tx_loadsz;
3222 if (!up->capabilities)
3223 up->capabilities = uart_config[type].flags;
3224 }
3225
3226 set_io_from_upio(port);
3227
3228 /* default dma handlers */
3229 if (up->dma) {
3230 if (!up->dma->tx_dma)
3231 up->dma->tx_dma = serial8250_tx_dma;
3232 if (!up->dma->rx_dma)
3233 up->dma->rx_dma = serial8250_rx_dma;
3234 }
3235 }
3236 EXPORT_SYMBOL_GPL(serial8250_set_defaults);
3237
3238 #ifdef CONFIG_SERIAL_8250_CONSOLE
3239
3240 static void serial8250_console_putchar(struct uart_port *port, int ch)
3241 {
3242 struct uart_8250_port *up = up_to_u8250p(port);
3243
3244 wait_for_xmitr(up, UART_LSR_THRE);
3245 serial_port_out(port, UART_TX, ch);
3246 }
3247
3248 /*
3249 * Restore serial console when h/w power-off detected
3250 */
3251 static void serial8250_console_restore(struct uart_8250_port *up)
3252 {
3253 struct uart_port *port = &up->port;
3254 struct ktermios termios;
3255 unsigned int baud, quot, frac = 0;
3256
3257 termios.c_cflag = port->cons->cflag;
3258 if (port->state->port.tty && termios.c_cflag == 0)
3259 termios.c_cflag = port->state->port.tty->termios.c_cflag;
3260
3261 baud = serial8250_get_baud_rate(port, &termios, NULL);
3262 quot = serial8250_get_divisor(port, baud, &frac);
3263
3264 serial8250_set_divisor(port, baud, quot, frac);
3265 serial_port_out(port, UART_LCR, up->lcr);
3266 serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
3267 }
3268
3269 /*
3270 * Print a string to the serial port trying not to disturb
3271 * any possible real use of the port...
3272 *
3273 * The console_lock must be held when we get here.
3274 *
3275 * Doing runtime PM is really a bad idea for the kernel console.
3276 * Thus, we assume the function is called when device is powered up.
3277 */
3278 void serial8250_console_write(struct uart_8250_port *up, const char *s,
3279 unsigned int count)
3280 {
3281 struct uart_8250_em485 *em485 = up->em485;
3282 struct uart_port *port = &up->port;
3283 unsigned long flags;
3284 unsigned int ier;
3285 int locked = 1;
3286
3287 touch_nmi_watchdog();
3288
3289 if (oops_in_progress)
3290 locked = spin_trylock_irqsave(&port->lock, flags);
3291 else
3292 spin_lock_irqsave(&port->lock, flags);
3293
3294 /*
3295 * First save the IER then disable the interrupts
3296 */
3297 ier = serial_port_in(port, UART_IER);
3298
3299 if (up->capabilities & UART_CAP_UUE)
3300 serial_port_out(port, UART_IER, UART_IER_UUE);
3301 else
3302 serial_port_out(port, UART_IER, 0);
3303
3304 /* check scratch reg to see if port powered off during system sleep */
3305 if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
3306 serial8250_console_restore(up);
3307 up->canary = 0;
3308 }
3309
3310 if (em485) {
3311 if (em485->tx_stopped)
3312 up->rs485_start_tx(up);
3313 mdelay(port->rs485.delay_rts_before_send);
3314 }
3315
3316 uart_console_write(port, s, count, serial8250_console_putchar);
3317
3318 /*
3319 * Finally, wait for transmitter to become empty
3320 * and restore the IER
3321 */
3322 wait_for_xmitr(up, BOTH_EMPTY);
3323
3324 if (em485) {
3325 mdelay(port->rs485.delay_rts_after_send);
3326 if (em485->tx_stopped)
3327 up->rs485_stop_tx(up);
3328 }
3329
3330 serial_port_out(port, UART_IER, ier);
3331
3332 /*
3333 * The receive handling will happen properly because the
3334 * receive ready bit will still be set; it is not cleared
3335 * on read. However, modem control will not, we must
3336 * call it if we have saved something in the saved flags
3337 * while processing with interrupts off.
3338 */
3339 if (up->msr_saved_flags)
3340 serial8250_modem_status(up);
3341
3342 if (locked)
3343 spin_unlock_irqrestore(&port->lock, flags);
3344 }
3345
3346 static unsigned int probe_baud(struct uart_port *port)
3347 {
3348 unsigned char lcr, dll, dlm;
3349 unsigned int quot;
3350
3351 lcr = serial_port_in(port, UART_LCR);
3352 serial_port_out(port, UART_LCR, lcr | UART_LCR_DLAB);
3353 dll = serial_port_in(port, UART_DLL);
3354 dlm = serial_port_in(port, UART_DLM);
3355 serial_port_out(port, UART_LCR, lcr);
3356
3357 quot = (dlm << 8) | dll;
3358 return (port->uartclk / 16) / quot;
3359 }
3360
3361 int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
3362 {
3363 int baud = 9600;
3364 int bits = 8;
3365 int parity = 'n';
3366 int flow = 'n';
3367 int ret;
3368
3369 if (!port->iobase && !port->membase)
3370 return -ENODEV;
3371
3372 if (options)
3373 uart_parse_options(options, &baud, &parity, &bits, &flow);
3374 else if (probe)
3375 baud = probe_baud(port);
3376
3377 ret = uart_set_options(port, port->cons, baud, parity, bits, flow);
3378 if (ret)
3379 return ret;
3380
3381 if (port->dev)
3382 pm_runtime_get_sync(port->dev);
3383
3384 return 0;
3385 }
3386
3387 int serial8250_console_exit(struct uart_port *port)
3388 {
3389 if (port->dev)
3390 pm_runtime_put_sync(port->dev);
3391
3392 return 0;
3393 }
3394
3395 #endif /* CONFIG_SERIAL_8250_CONSOLE */
3396
3397 MODULE_LICENSE("GPL");
Linux with added FPC-III support