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Linux 3.12.39
[linux/fpc-iii.git] / drivers / tty / serial / ip22zilog.c
bloba90f4089d080dfc5ae9c0d5a695566ab6918614b
1 /*
2 * Driver for Zilog serial chips found on SGI workstations and
3 * servers. This driver could actually be made more generic.
4 *
5 * This is based on the drivers/serial/sunzilog.c code as of 2.6.0-test7 and the
6 * old drivers/sgi/char/sgiserial.c code which itself is based of the original
7 * drivers/sbus/char/zs.c code. A lot of code has been simply moved over
8 * directly from there but much has been rewritten. Credits therefore go out
9 * to David S. Miller, Eddie C. Dost, Pete Zaitcev, Ted Ts'o and Alex Buell
10 * for their work there.
11 *
12 * Copyright (C) 2002 Ralf Baechle (ralf@linux-mips.org)
13 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
14 */
15 #include <linux/module.h>
16 #include <linux/kernel.h>
17 #include <linux/errno.h>
18 #include <linux/delay.h>
19 #include <linux/tty.h>
20 #include <linux/tty_flip.h>
21 #include <linux/major.h>
22 #include <linux/string.h>
23 #include <linux/ptrace.h>
24 #include <linux/ioport.h>
25 #include <linux/slab.h>
26 #include <linux/circ_buf.h>
27 #include <linux/serial.h>
28 #include <linux/sysrq.h>
29 #include <linux/console.h>
30 #include <linux/spinlock.h>
31 #include <linux/init.h>
32
33 #include <asm/io.h>
34 #include <asm/irq.h>
35 #include <asm/sgialib.h>
36 #include <asm/sgi/ioc.h>
37 #include <asm/sgi/hpc3.h>
38 #include <asm/sgi/ip22.h>
39
40 #if defined(CONFIG_SERIAL_IP22_ZILOG_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
41 #define SUPPORT_SYSRQ
42 #endif
43
44 #include <linux/serial_core.h>
45
46 #include "ip22zilog.h"
47
48 /*
49 * On IP22 we need to delay after register accesses but we do not need to
50 * flush writes.
51 */
52 #define ZSDELAY() udelay(5)
53 #define ZSDELAY_LONG() udelay(20)
54 #define ZS_WSYNC(channel) do { } while (0)
55
56 #define NUM_IP22ZILOG 1
57 #define NUM_CHANNELS (NUM_IP22ZILOG * 2)
58
59 #define ZS_CLOCK 3672000 /* Zilog input clock rate. */
60 #define ZS_CLOCK_DIVISOR 16 /* Divisor this driver uses. */
61
62 /*
63 * We wrap our port structure around the generic uart_port.
64 */
65 struct uart_ip22zilog_port {
66 struct uart_port port;
67
68 /* IRQ servicing chain. */
69 struct uart_ip22zilog_port *next;
70
71 /* Current values of Zilog write registers. */
72 unsigned char curregs[NUM_ZSREGS];
73
74 unsigned int flags;
75 #define IP22ZILOG_FLAG_IS_CONS 0x00000004
76 #define IP22ZILOG_FLAG_IS_KGDB 0x00000008
77 #define IP22ZILOG_FLAG_MODEM_STATUS 0x00000010
78 #define IP22ZILOG_FLAG_IS_CHANNEL_A 0x00000020
79 #define IP22ZILOG_FLAG_REGS_HELD 0x00000040
80 #define IP22ZILOG_FLAG_TX_STOPPED 0x00000080
81 #define IP22ZILOG_FLAG_TX_ACTIVE 0x00000100
82 #define IP22ZILOG_FLAG_RESET_DONE 0x00000200
83
84 unsigned int tty_break;
85
86 unsigned char parity_mask;
87 unsigned char prev_status;
88 };
89
90 #define ZILOG_CHANNEL_FROM_PORT(PORT) ((struct zilog_channel *)((PORT)->membase))
91 #define UART_ZILOG(PORT) ((struct uart_ip22zilog_port *)(PORT))
92 #define IP22ZILOG_GET_CURR_REG(PORT, REGNUM) \
93 (UART_ZILOG(PORT)->curregs[REGNUM])
94 #define IP22ZILOG_SET_CURR_REG(PORT, REGNUM, REGVAL) \
95 ((UART_ZILOG(PORT)->curregs[REGNUM]) = (REGVAL))
96 #define ZS_IS_CONS(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_CONS)
97 #define ZS_IS_KGDB(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_KGDB)
98 #define ZS_WANTS_MODEM_STATUS(UP) ((UP)->flags & IP22ZILOG_FLAG_MODEM_STATUS)
99 #define ZS_IS_CHANNEL_A(UP) ((UP)->flags & IP22ZILOG_FLAG_IS_CHANNEL_A)
100 #define ZS_REGS_HELD(UP) ((UP)->flags & IP22ZILOG_FLAG_REGS_HELD)
101 #define ZS_TX_STOPPED(UP) ((UP)->flags & IP22ZILOG_FLAG_TX_STOPPED)
102 #define ZS_TX_ACTIVE(UP) ((UP)->flags & IP22ZILOG_FLAG_TX_ACTIVE)
103
104 /* Reading and writing Zilog8530 registers. The delays are to make this
105 * driver work on the IP22 which needs a settling delay after each chip
106 * register access, other machines handle this in hardware via auxiliary
107 * flip-flops which implement the settle time we do in software.
108 *
109 * The port lock must be held and local IRQs must be disabled
110 * when {read,write}_zsreg is invoked.
111 */
112 static unsigned char read_zsreg(struct zilog_channel *channel,
113 unsigned char reg)
114 {
115 unsigned char retval;
116
117 writeb(reg, &channel->control);
118 ZSDELAY();
119 retval = readb(&channel->control);
120 ZSDELAY();
121
122 return retval;
123 }
124
125 static void write_zsreg(struct zilog_channel *channel,
126 unsigned char reg, unsigned char value)
127 {
128 writeb(reg, &channel->control);
129 ZSDELAY();
130 writeb(value, &channel->control);
131 ZSDELAY();
132 }
133
134 static void ip22zilog_clear_fifo(struct zilog_channel *channel)
135 {
136 int i;
137
138 for (i = 0; i < 32; i++) {
139 unsigned char regval;
140
141 regval = readb(&channel->control);
142 ZSDELAY();
143 if (regval & Rx_CH_AV)
144 break;
145
146 regval = read_zsreg(channel, R1);
147 readb(&channel->data);
148 ZSDELAY();
149
150 if (regval & (PAR_ERR | Rx_OVR | CRC_ERR)) {
151 writeb(ERR_RES, &channel->control);
152 ZSDELAY();
153 ZS_WSYNC(channel);
154 }
155 }
156 }
157
158 /* This function must only be called when the TX is not busy. The UART
159 * port lock must be held and local interrupts disabled.
160 */
161 static void __load_zsregs(struct zilog_channel *channel, unsigned char *regs)
162 {
163 int i;
164
165 /* Let pending transmits finish. */
166 for (i = 0; i < 1000; i++) {
167 unsigned char stat = read_zsreg(channel, R1);
168 if (stat & ALL_SNT)
169 break;
170 udelay(100);
171 }
172
173 writeb(ERR_RES, &channel->control);
174 ZSDELAY();
175 ZS_WSYNC(channel);
176
177 ip22zilog_clear_fifo(channel);
178
179 /* Disable all interrupts. */
180 write_zsreg(channel, R1,
181 regs[R1] & ~(RxINT_MASK | TxINT_ENAB | EXT_INT_ENAB));
182
183 /* Set parity, sync config, stop bits, and clock divisor. */
184 write_zsreg(channel, R4, regs[R4]);
185
186 /* Set misc. TX/RX control bits. */
187 write_zsreg(channel, R10, regs[R10]);
188
189 /* Set TX/RX controls sans the enable bits. */
190 write_zsreg(channel, R3, regs[R3] & ~RxENAB);
191 write_zsreg(channel, R5, regs[R5] & ~TxENAB);
192
193 /* Synchronous mode config. */
194 write_zsreg(channel, R6, regs[R6]);
195 write_zsreg(channel, R7, regs[R7]);
196
197 /* Don't mess with the interrupt vector (R2, unused by us) and
198 * master interrupt control (R9). We make sure this is setup
199 * properly at probe time then never touch it again.
200 */
201
202 /* Disable baud generator. */
203 write_zsreg(channel, R14, regs[R14] & ~BRENAB);
204
205 /* Clock mode control. */
206 write_zsreg(channel, R11, regs[R11]);
207
208 /* Lower and upper byte of baud rate generator divisor. */
209 write_zsreg(channel, R12, regs[R12]);
210 write_zsreg(channel, R13, regs[R13]);
211
212 /* Now rewrite R14, with BRENAB (if set). */
213 write_zsreg(channel, R14, regs[R14]);
214
215 /* External status interrupt control. */
216 write_zsreg(channel, R15, regs[R15]);
217
218 /* Reset external status interrupts. */
219 write_zsreg(channel, R0, RES_EXT_INT);
220 write_zsreg(channel, R0, RES_EXT_INT);
221
222 /* Rewrite R3/R5, this time without enables masked. */
223 write_zsreg(channel, R3, regs[R3]);
224 write_zsreg(channel, R5, regs[R5]);
225
226 /* Rewrite R1, this time without IRQ enabled masked. */
227 write_zsreg(channel, R1, regs[R1]);
228 }
229
230 /* Reprogram the Zilog channel HW registers with the copies found in the
231 * software state struct. If the transmitter is busy, we defer this update
232 * until the next TX complete interrupt. Else, we do it right now.
233 *
234 * The UART port lock must be held and local interrupts disabled.
235 */
236 static void ip22zilog_maybe_update_regs(struct uart_ip22zilog_port *up,
237 struct zilog_channel *channel)
238 {
239 if (!ZS_REGS_HELD(up)) {
240 if (ZS_TX_ACTIVE(up)) {
241 up->flags |= IP22ZILOG_FLAG_REGS_HELD;
242 } else {
243 __load_zsregs(channel, up->curregs);
244 }
245 }
246 }
247
248 #define Rx_BRK 0x0100 /* BREAK event software flag. */
249 #define Rx_SYS 0x0200 /* SysRq event software flag. */
250
251 static bool ip22zilog_receive_chars(struct uart_ip22zilog_port *up,
252 struct zilog_channel *channel)
253 {
254 unsigned char ch, flag;
255 unsigned int r1;
256 bool push = up->port.state != NULL;
257
258 for (;;) {
259 ch = readb(&channel->control);
260 ZSDELAY();
261 if (!(ch & Rx_CH_AV))
262 break;
263
264 r1 = read_zsreg(channel, R1);
265 if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR)) {
266 writeb(ERR_RES, &channel->control);
267 ZSDELAY();
268 ZS_WSYNC(channel);
269 }
270
271 ch = readb(&channel->data);
272 ZSDELAY();
273
274 ch &= up->parity_mask;
275
276 /* Handle the null char got when BREAK is removed. */
277 if (!ch)
278 r1 |= up->tty_break;
279
280 /* A real serial line, record the character and status. */
281 flag = TTY_NORMAL;
282 up->port.icount.rx++;
283 if (r1 & (PAR_ERR | Rx_OVR | CRC_ERR | Rx_SYS | Rx_BRK)) {
284 up->tty_break = 0;
285
286 if (r1 & (Rx_SYS | Rx_BRK)) {
287 up->port.icount.brk++;
288 if (r1 & Rx_SYS)
289 continue;
290 r1 &= ~(PAR_ERR | CRC_ERR);
291 }
292 else if (r1 & PAR_ERR)
293 up->port.icount.parity++;
294 else if (r1 & CRC_ERR)
295 up->port.icount.frame++;
296 if (r1 & Rx_OVR)
297 up->port.icount.overrun++;
298 r1 &= up->port.read_status_mask;
299 if (r1 & Rx_BRK)
300 flag = TTY_BREAK;
301 else if (r1 & PAR_ERR)
302 flag = TTY_PARITY;
303 else if (r1 & CRC_ERR)
304 flag = TTY_FRAME;
305 }
306
307 if (uart_handle_sysrq_char(&up->port, ch))
308 continue;
309
310 if (push)
311 uart_insert_char(&up->port, r1, Rx_OVR, ch, flag);
312 }
313 return push;
314 }
315
316 static void ip22zilog_status_handle(struct uart_ip22zilog_port *up,
317 struct zilog_channel *channel)
318 {
319 unsigned char status;
320
321 status = readb(&channel->control);
322 ZSDELAY();
323
324 writeb(RES_EXT_INT, &channel->control);
325 ZSDELAY();
326 ZS_WSYNC(channel);
327
328 if (up->curregs[R15] & BRKIE) {
329 if ((status & BRK_ABRT) && !(up->prev_status & BRK_ABRT)) {
330 if (uart_handle_break(&up->port))
331 up->tty_break = Rx_SYS;
332 else
333 up->tty_break = Rx_BRK;
334 }
335 }
336
337 if (ZS_WANTS_MODEM_STATUS(up)) {
338 if (status & SYNC)
339 up->port.icount.dsr++;
340
341 /* The Zilog just gives us an interrupt when DCD/CTS/etc. change.
342 * But it does not tell us which bit has changed, we have to keep
343 * track of this ourselves.
344 */
345 if ((status ^ up->prev_status) ^ DCD)
346 uart_handle_dcd_change(&up->port,
347 (status & DCD));
348 if ((status ^ up->prev_status) ^ CTS)
349 uart_handle_cts_change(&up->port,
350 (status & CTS));
351
352 wake_up_interruptible(&up->port.state->port.delta_msr_wait);
353 }
354
355 up->prev_status = status;
356 }
357
358 static void ip22zilog_transmit_chars(struct uart_ip22zilog_port *up,
359 struct zilog_channel *channel)
360 {
361 struct circ_buf *xmit;
362
363 if (ZS_IS_CONS(up)) {
364 unsigned char status = readb(&channel->control);
365 ZSDELAY();
366
367 /* TX still busy? Just wait for the next TX done interrupt.
368 *
369 * It can occur because of how we do serial console writes. It would
370 * be nice to transmit console writes just like we normally would for
371 * a TTY line. (ie. buffered and TX interrupt driven). That is not
372 * easy because console writes cannot sleep. One solution might be
373 * to poll on enough port->xmit space becoming free. -DaveM
374 */
375 if (!(status & Tx_BUF_EMP))
376 return;
377 }
378
379 up->flags &= ~IP22ZILOG_FLAG_TX_ACTIVE;
380
381 if (ZS_REGS_HELD(up)) {
382 __load_zsregs(channel, up->curregs);
383 up->flags &= ~IP22ZILOG_FLAG_REGS_HELD;
384 }
385
386 if (ZS_TX_STOPPED(up)) {
387 up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
388 goto ack_tx_int;
389 }
390
391 if (up->port.x_char) {
392 up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
393 writeb(up->port.x_char, &channel->data);
394 ZSDELAY();
395 ZS_WSYNC(channel);
396
397 up->port.icount.tx++;
398 up->port.x_char = 0;
399 return;
400 }
401
402 if (up->port.state == NULL)
403 goto ack_tx_int;
404 xmit = &up->port.state->xmit;
405 if (uart_circ_empty(xmit))
406 goto ack_tx_int;
407 if (uart_tx_stopped(&up->port))
408 goto ack_tx_int;
409
410 up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
411 writeb(xmit->buf[xmit->tail], &channel->data);
412 ZSDELAY();
413 ZS_WSYNC(channel);
414
415 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
416 up->port.icount.tx++;
417
418 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
419 uart_write_wakeup(&up->port);
420
421 return;
422
423 ack_tx_int:
424 writeb(RES_Tx_P, &channel->control);
425 ZSDELAY();
426 ZS_WSYNC(channel);
427 }
428
429 static irqreturn_t ip22zilog_interrupt(int irq, void *dev_id)
430 {
431 struct uart_ip22zilog_port *up = dev_id;
432
433 while (up) {
434 struct zilog_channel *channel
435 = ZILOG_CHANNEL_FROM_PORT(&up->port);
436 unsigned char r3;
437 bool push = false;
438
439 spin_lock(&up->port.lock);
440 r3 = read_zsreg(channel, R3);
441
442 /* Channel A */
443 if (r3 & (CHAEXT | CHATxIP | CHARxIP)) {
444 writeb(RES_H_IUS, &channel->control);
445 ZSDELAY();
446 ZS_WSYNC(channel);
447
448 if (r3 & CHARxIP)
449 push = ip22zilog_receive_chars(up, channel);
450 if (r3 & CHAEXT)
451 ip22zilog_status_handle(up, channel);
452 if (r3 & CHATxIP)
453 ip22zilog_transmit_chars(up, channel);
454 }
455 spin_unlock(&up->port.lock);
456
457 if (push)
458 tty_flip_buffer_push(&up->port.state->port);
459
460 /* Channel B */
461 up = up->next;
462 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
463 push = false;
464
465 spin_lock(&up->port.lock);
466 if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) {
467 writeb(RES_H_IUS, &channel->control);
468 ZSDELAY();
469 ZS_WSYNC(channel);
470
471 if (r3 & CHBRxIP)
472 push = ip22zilog_receive_chars(up, channel);
473 if (r3 & CHBEXT)
474 ip22zilog_status_handle(up, channel);
475 if (r3 & CHBTxIP)
476 ip22zilog_transmit_chars(up, channel);
477 }
478 spin_unlock(&up->port.lock);
479
480 if (push)
481 tty_flip_buffer_push(&up->port.state->port);
482
483 up = up->next;
484 }
485
486 return IRQ_HANDLED;
487 }
488
489 /* A convenient way to quickly get R0 status. The caller must _not_ hold the
490 * port lock, it is acquired here.
491 */
492 static __inline__ unsigned char ip22zilog_read_channel_status(struct uart_port *port)
493 {
494 struct zilog_channel *channel;
495 unsigned char status;
496
497 channel = ZILOG_CHANNEL_FROM_PORT(port);
498 status = readb(&channel->control);
499 ZSDELAY();
500
501 return status;
502 }
503
504 /* The port lock is not held. */
505 static unsigned int ip22zilog_tx_empty(struct uart_port *port)
506 {
507 unsigned long flags;
508 unsigned char status;
509 unsigned int ret;
510
511 spin_lock_irqsave(&port->lock, flags);
512
513 status = ip22zilog_read_channel_status(port);
514
515 spin_unlock_irqrestore(&port->lock, flags);
516
517 if (status & Tx_BUF_EMP)
518 ret = TIOCSER_TEMT;
519 else
520 ret = 0;
521
522 return ret;
523 }
524
525 /* The port lock is held and interrupts are disabled. */
526 static unsigned int ip22zilog_get_mctrl(struct uart_port *port)
527 {
528 unsigned char status;
529 unsigned int ret;
530
531 status = ip22zilog_read_channel_status(port);
532
533 ret = 0;
534 if (status & DCD)
535 ret |= TIOCM_CAR;
536 if (status & SYNC)
537 ret |= TIOCM_DSR;
538 if (status & CTS)
539 ret |= TIOCM_CTS;
540
541 return ret;
542 }
543
544 /* The port lock is held and interrupts are disabled. */
545 static void ip22zilog_set_mctrl(struct uart_port *port, unsigned int mctrl)
546 {
547 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
548 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
549 unsigned char set_bits, clear_bits;
550
551 set_bits = clear_bits = 0;
552
553 if (mctrl & TIOCM_RTS)
554 set_bits |= RTS;
555 else
556 clear_bits |= RTS;
557 if (mctrl & TIOCM_DTR)
558 set_bits |= DTR;
559 else
560 clear_bits |= DTR;
561
562 /* NOTE: Not subject to 'transmitter active' rule. */
563 up->curregs[R5] |= set_bits;
564 up->curregs[R5] &= ~clear_bits;
565 write_zsreg(channel, R5, up->curregs[R5]);
566 }
567
568 /* The port lock is held and interrupts are disabled. */
569 static void ip22zilog_stop_tx(struct uart_port *port)
570 {
571 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
572
573 up->flags |= IP22ZILOG_FLAG_TX_STOPPED;
574 }
575
576 /* The port lock is held and interrupts are disabled. */
577 static void ip22zilog_start_tx(struct uart_port *port)
578 {
579 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
580 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
581 unsigned char status;
582
583 up->flags |= IP22ZILOG_FLAG_TX_ACTIVE;
584 up->flags &= ~IP22ZILOG_FLAG_TX_STOPPED;
585
586 status = readb(&channel->control);
587 ZSDELAY();
588
589 /* TX busy? Just wait for the TX done interrupt. */
590 if (!(status & Tx_BUF_EMP))
591 return;
592
593 /* Send the first character to jump-start the TX done
594 * IRQ sending engine.
595 */
596 if (port->x_char) {
597 writeb(port->x_char, &channel->data);
598 ZSDELAY();
599 ZS_WSYNC(channel);
600
601 port->icount.tx++;
602 port->x_char = 0;
603 } else {
604 struct circ_buf *xmit = &port->state->xmit;
605
606 writeb(xmit->buf[xmit->tail], &channel->data);
607 ZSDELAY();
608 ZS_WSYNC(channel);
609
610 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
611 port->icount.tx++;
612
613 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
614 uart_write_wakeup(&up->port);
615 }
616 }
617
618 /* The port lock is held and interrupts are disabled. */
619 static void ip22zilog_stop_rx(struct uart_port *port)
620 {
621 struct uart_ip22zilog_port *up = UART_ZILOG(port);
622 struct zilog_channel *channel;
623
624 if (ZS_IS_CONS(up))
625 return;
626
627 channel = ZILOG_CHANNEL_FROM_PORT(port);
628
629 /* Disable all RX interrupts. */
630 up->curregs[R1] &= ~RxINT_MASK;
631 ip22zilog_maybe_update_regs(up, channel);
632 }
633
634 /* The port lock is held. */
635 static void ip22zilog_enable_ms(struct uart_port *port)
636 {
637 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
638 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
639 unsigned char new_reg;
640
641 new_reg = up->curregs[R15] | (DCDIE | SYNCIE | CTSIE);
642 if (new_reg != up->curregs[R15]) {
643 up->curregs[R15] = new_reg;
644
645 /* NOTE: Not subject to 'transmitter active' rule. */
646 write_zsreg(channel, R15, up->curregs[R15]);
647 }
648 }
649
650 /* The port lock is not held. */
651 static void ip22zilog_break_ctl(struct uart_port *port, int break_state)
652 {
653 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
654 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
655 unsigned char set_bits, clear_bits, new_reg;
656 unsigned long flags;
657
658 set_bits = clear_bits = 0;
659
660 if (break_state)
661 set_bits |= SND_BRK;
662 else
663 clear_bits |= SND_BRK;
664
665 spin_lock_irqsave(&port->lock, flags);
666
667 new_reg = (up->curregs[R5] | set_bits) & ~clear_bits;
668 if (new_reg != up->curregs[R5]) {
669 up->curregs[R5] = new_reg;
670
671 /* NOTE: Not subject to 'transmitter active' rule. */
672 write_zsreg(channel, R5, up->curregs[R5]);
673 }
674
675 spin_unlock_irqrestore(&port->lock, flags);
676 }
677
678 static void __ip22zilog_reset(struct uart_ip22zilog_port *up)
679 {
680 struct zilog_channel *channel;
681 int i;
682
683 if (up->flags & IP22ZILOG_FLAG_RESET_DONE)
684 return;
685
686 /* Let pending transmits finish. */
687 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
688 for (i = 0; i < 1000; i++) {
689 unsigned char stat = read_zsreg(channel, R1);
690 if (stat & ALL_SNT)
691 break;
692 udelay(100);
693 }
694
695 if (!ZS_IS_CHANNEL_A(up)) {
696 up++;
697 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
698 }
699 write_zsreg(channel, R9, FHWRES);
700 ZSDELAY_LONG();
701 (void) read_zsreg(channel, R0);
702
703 up->flags |= IP22ZILOG_FLAG_RESET_DONE;
704 up->next->flags |= IP22ZILOG_FLAG_RESET_DONE;
705 }
706
707 static void __ip22zilog_startup(struct uart_ip22zilog_port *up)
708 {
709 struct zilog_channel *channel;
710
711 channel = ZILOG_CHANNEL_FROM_PORT(&up->port);
712
713 __ip22zilog_reset(up);
714
715 __load_zsregs(channel, up->curregs);
716 /* set master interrupt enable */
717 write_zsreg(channel, R9, up->curregs[R9]);
718 up->prev_status = readb(&channel->control);
719
720 /* Enable receiver and transmitter. */
721 up->curregs[R3] |= RxENAB;
722 up->curregs[R5] |= TxENAB;
723
724 up->curregs[R1] |= EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
725 ip22zilog_maybe_update_regs(up, channel);
726 }
727
728 static int ip22zilog_startup(struct uart_port *port)
729 {
730 struct uart_ip22zilog_port *up = UART_ZILOG(port);
731 unsigned long flags;
732
733 if (ZS_IS_CONS(up))
734 return 0;
735
736 spin_lock_irqsave(&port->lock, flags);
737 __ip22zilog_startup(up);
738 spin_unlock_irqrestore(&port->lock, flags);
739 return 0;
740 }
741
742 /*
743 * The test for ZS_IS_CONS is explained by the following e-mail:
744 *****
745 * From: Russell King <rmk@arm.linux.org.uk>
746 * Date: Sun, 8 Dec 2002 10:18:38 +0000
747 *
748 * On Sun, Dec 08, 2002 at 02:43:36AM -0500, Pete Zaitcev wrote:
749 * > I boot my 2.5 boxes using "console=ttyS0,9600" argument,
750 * > and I noticed that something is not right with reference
751 * > counting in this case. It seems that when the console
752 * > is open by kernel initially, this is not accounted
753 * > as an open, and uart_startup is not called.
754 *
755 * That is correct. We are unable to call uart_startup when the serial
756 * console is initialised because it may need to allocate memory (as
757 * request_irq does) and the memory allocators may not have been
758 * initialised.
759 *
760 * 1. initialise the port into a state where it can send characters in the
761 * console write method.
762 *
763 * 2. don't do the actual hardware shutdown in your shutdown() method (but
764 * do the normal software shutdown - ie, free irqs etc)
765 *****
766 */
767 static void ip22zilog_shutdown(struct uart_port *port)
768 {
769 struct uart_ip22zilog_port *up = UART_ZILOG(port);
770 struct zilog_channel *channel;
771 unsigned long flags;
772
773 if (ZS_IS_CONS(up))
774 return;
775
776 spin_lock_irqsave(&port->lock, flags);
777
778 channel = ZILOG_CHANNEL_FROM_PORT(port);
779
780 /* Disable receiver and transmitter. */
781 up->curregs[R3] &= ~RxENAB;
782 up->curregs[R5] &= ~TxENAB;
783
784 /* Disable all interrupts and BRK assertion. */
785 up->curregs[R1] &= ~(EXT_INT_ENAB | TxINT_ENAB | RxINT_MASK);
786 up->curregs[R5] &= ~SND_BRK;
787 ip22zilog_maybe_update_regs(up, channel);
788
789 spin_unlock_irqrestore(&port->lock, flags);
790 }
791
792 /* Shared by TTY driver and serial console setup. The port lock is held
793 * and local interrupts are disabled.
794 */
795 static void
796 ip22zilog_convert_to_zs(struct uart_ip22zilog_port *up, unsigned int cflag,
797 unsigned int iflag, int brg)
798 {
799
800 up->curregs[R10] = NRZ;
801 up->curregs[R11] = TCBR | RCBR;
802
803 /* Program BAUD and clock source. */
804 up->curregs[R4] &= ~XCLK_MASK;
805 up->curregs[R4] |= X16CLK;
806 up->curregs[R12] = brg & 0xff;
807 up->curregs[R13] = (brg >> 8) & 0xff;
808 up->curregs[R14] = BRENAB;
809
810 /* Character size, stop bits, and parity. */
811 up->curregs[3] &= ~RxN_MASK;
812 up->curregs[5] &= ~TxN_MASK;
813 switch (cflag & CSIZE) {
814 case CS5:
815 up->curregs[3] |= Rx5;
816 up->curregs[5] |= Tx5;
817 up->parity_mask = 0x1f;
818 break;
819 case CS6:
820 up->curregs[3] |= Rx6;
821 up->curregs[5] |= Tx6;
822 up->parity_mask = 0x3f;
823 break;
824 case CS7:
825 up->curregs[3] |= Rx7;
826 up->curregs[5] |= Tx7;
827 up->parity_mask = 0x7f;
828 break;
829 case CS8:
830 default:
831 up->curregs[3] |= Rx8;
832 up->curregs[5] |= Tx8;
833 up->parity_mask = 0xff;
834 break;
835 };
836 up->curregs[4] &= ~0x0c;
837 if (cflag & CSTOPB)
838 up->curregs[4] |= SB2;
839 else
840 up->curregs[4] |= SB1;
841 if (cflag & PARENB)
842 up->curregs[4] |= PAR_ENAB;
843 else
844 up->curregs[4] &= ~PAR_ENAB;
845 if (!(cflag & PARODD))
846 up->curregs[4] |= PAR_EVEN;
847 else
848 up->curregs[4] &= ~PAR_EVEN;
849
850 up->port.read_status_mask = Rx_OVR;
851 if (iflag & INPCK)
852 up->port.read_status_mask |= CRC_ERR | PAR_ERR;
853 if (iflag & (IGNBRK | BRKINT | PARMRK))
854 up->port.read_status_mask |= BRK_ABRT;
855
856 up->port.ignore_status_mask = 0;
857 if (iflag & IGNPAR)
858 up->port.ignore_status_mask |= CRC_ERR | PAR_ERR;
859 if (iflag & IGNBRK) {
860 up->port.ignore_status_mask |= BRK_ABRT;
861 if (iflag & IGNPAR)
862 up->port.ignore_status_mask |= Rx_OVR;
863 }
864
865 if ((cflag & CREAD) == 0)
866 up->port.ignore_status_mask = 0xff;
867 }
868
869 /* The port lock is not held. */
870 static void
871 ip22zilog_set_termios(struct uart_port *port, struct ktermios *termios,
872 struct ktermios *old)
873 {
874 struct uart_ip22zilog_port *up = (struct uart_ip22zilog_port *) port;
875 unsigned long flags;
876 int baud, brg;
877
878 baud = uart_get_baud_rate(port, termios, old, 1200, 76800);
879
880 spin_lock_irqsave(&up->port.lock, flags);
881
882 brg = BPS_TO_BRG(baud, ZS_CLOCK / ZS_CLOCK_DIVISOR);
883
884 ip22zilog_convert_to_zs(up, termios->c_cflag, termios->c_iflag, brg);
885
886 if (UART_ENABLE_MS(&up->port, termios->c_cflag))
887 up->flags |= IP22ZILOG_FLAG_MODEM_STATUS;
888 else
889 up->flags &= ~IP22ZILOG_FLAG_MODEM_STATUS;
890
891 ip22zilog_maybe_update_regs(up, ZILOG_CHANNEL_FROM_PORT(port));
892 uart_update_timeout(port, termios->c_cflag, baud);
893
894 spin_unlock_irqrestore(&up->port.lock, flags);
895 }
896
897 static const char *ip22zilog_type(struct uart_port *port)
898 {
899 return "IP22-Zilog";
900 }
901
902 /* We do not request/release mappings of the registers here, this
903 * happens at early serial probe time.
904 */
905 static void ip22zilog_release_port(struct uart_port *port)
906 {
907 }
908
909 static int ip22zilog_request_port(struct uart_port *port)
910 {
911 return 0;
912 }
913
914 /* These do not need to do anything interesting either. */
915 static void ip22zilog_config_port(struct uart_port *port, int flags)
916 {
917 }
918
919 /* We do not support letting the user mess with the divisor, IRQ, etc. */
920 static int ip22zilog_verify_port(struct uart_port *port, struct serial_struct *ser)
921 {
922 return -EINVAL;
923 }
924
925 static struct uart_ops ip22zilog_pops = {
926 .tx_empty = ip22zilog_tx_empty,
927 .set_mctrl = ip22zilog_set_mctrl,
928 .get_mctrl = ip22zilog_get_mctrl,
929 .stop_tx = ip22zilog_stop_tx,
930 .start_tx = ip22zilog_start_tx,
931 .stop_rx = ip22zilog_stop_rx,
932 .enable_ms = ip22zilog_enable_ms,
933 .break_ctl = ip22zilog_break_ctl,
934 .startup = ip22zilog_startup,
935 .shutdown = ip22zilog_shutdown,
936 .set_termios = ip22zilog_set_termios,
937 .type = ip22zilog_type,
938 .release_port = ip22zilog_release_port,
939 .request_port = ip22zilog_request_port,
940 .config_port = ip22zilog_config_port,
941 .verify_port = ip22zilog_verify_port,
942 };
943
944 static struct uart_ip22zilog_port *ip22zilog_port_table;
945 static struct zilog_layout **ip22zilog_chip_regs;
946
947 static struct uart_ip22zilog_port *ip22zilog_irq_chain;
948 static int zilog_irq = -1;
949
950 static void * __init alloc_one_table(unsigned long size)
951 {
952 return kzalloc(size, GFP_KERNEL);
953 }
954
955 static void __init ip22zilog_alloc_tables(void)
956 {
957 ip22zilog_port_table = (struct uart_ip22zilog_port *)
958 alloc_one_table(NUM_CHANNELS * sizeof(struct uart_ip22zilog_port));
959 ip22zilog_chip_regs = (struct zilog_layout **)
960 alloc_one_table(NUM_IP22ZILOG * sizeof(struct zilog_layout *));
961
962 if (ip22zilog_port_table == NULL || ip22zilog_chip_regs == NULL) {
963 panic("IP22-Zilog: Cannot allocate IP22-Zilog tables.");
964 }
965 }
966
967 /* Get the address of the registers for IP22-Zilog instance CHIP. */
968 static struct zilog_layout * __init get_zs(int chip)
969 {
970 unsigned long base;
971
972 if (chip < 0 || chip >= NUM_IP22ZILOG) {
973 panic("IP22-Zilog: Illegal chip number %d in get_zs.", chip);
974 }
975
976 /* Not probe-able, hard code it. */
977 base = (unsigned long) &sgioc->uart;
978
979 zilog_irq = SGI_SERIAL_IRQ;
980 request_mem_region(base, 8, "IP22-Zilog");
981
982 return (struct zilog_layout *) base;
983 }
984
985 #define ZS_PUT_CHAR_MAX_DELAY 2000 /* 10 ms */
986
987 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
988 static void ip22zilog_put_char(struct uart_port *port, int ch)
989 {
990 struct zilog_channel *channel = ZILOG_CHANNEL_FROM_PORT(port);
991 int loops = ZS_PUT_CHAR_MAX_DELAY;
992
993 /* This is a timed polling loop so do not switch the explicit
994 * udelay with ZSDELAY as that is a NOP on some platforms. -DaveM
995 */
996 do {
997 unsigned char val = readb(&channel->control);
998 if (val & Tx_BUF_EMP) {
999 ZSDELAY();
1000 break;
1001 }
1002 udelay(5);
1003 } while (--loops);
1004
1005 writeb(ch, &channel->data);
1006 ZSDELAY();
1007 ZS_WSYNC(channel);
1008 }
1009
1010 static void
1011 ip22zilog_console_write(struct console *con, const char *s, unsigned int count)
1012 {
1013 struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1014 unsigned long flags;
1015
1016 spin_lock_irqsave(&up->port.lock, flags);
1017 uart_console_write(&up->port, s, count, ip22zilog_put_char);
1018 udelay(2);
1019 spin_unlock_irqrestore(&up->port.lock, flags);
1020 }
1021
1022 static int __init ip22zilog_console_setup(struct console *con, char *options)
1023 {
1024 struct uart_ip22zilog_port *up = &ip22zilog_port_table[con->index];
1025 unsigned long flags;
1026 int baud = 9600, bits = 8;
1027 int parity = 'n';
1028 int flow = 'n';
1029
1030 up->flags |= IP22ZILOG_FLAG_IS_CONS;
1031
1032 printk(KERN_INFO "Console: ttyS%d (IP22-Zilog)\n", con->index);
1033
1034 spin_lock_irqsave(&up->port.lock, flags);
1035
1036 up->curregs[R15] |= BRKIE;
1037
1038 __ip22zilog_startup(up);
1039
1040 spin_unlock_irqrestore(&up->port.lock, flags);
1041
1042 if (options)
1043 uart_parse_options(options, &baud, &parity, &bits, &flow);
1044 return uart_set_options(&up->port, con, baud, parity, bits, flow);
1045 }
1046
1047 static struct uart_driver ip22zilog_reg;
1048
1049 static struct console ip22zilog_console = {
1050 .name = "ttyS",
1051 .write = ip22zilog_console_write,
1052 .device = uart_console_device,
1053 .setup = ip22zilog_console_setup,
1054 .flags = CON_PRINTBUFFER,
1055 .index = -1,
1056 .data = &ip22zilog_reg,
1057 };
1058 #endif /* CONFIG_SERIAL_IP22_ZILOG_CONSOLE */
1059
1060 static struct uart_driver ip22zilog_reg = {
1061 .owner = THIS_MODULE,
1062 .driver_name = "serial",
1063 .dev_name = "ttyS",
1064 .major = TTY_MAJOR,
1065 .minor = 64,
1066 .nr = NUM_CHANNELS,
1067 #ifdef CONFIG_SERIAL_IP22_ZILOG_CONSOLE
1068 .cons = &ip22zilog_console,
1069 #endif
1070 };
1071
1072 static void __init ip22zilog_prepare(void)
1073 {
1074 struct uart_ip22zilog_port *up;
1075 struct zilog_layout *rp;
1076 int channel, chip;
1077
1078 /*
1079 * Temporary fix.
1080 */
1081 for (channel = 0; channel < NUM_CHANNELS; channel++)
1082 spin_lock_init(&ip22zilog_port_table[channel].port.lock);
1083
1084 ip22zilog_irq_chain = &ip22zilog_port_table[NUM_CHANNELS - 1];
1085 up = &ip22zilog_port_table[0];
1086 for (channel = NUM_CHANNELS - 1 ; channel > 0; channel--)
1087 up[channel].next = &up[channel - 1];
1088 up[channel].next = NULL;
1089
1090 for (chip = 0; chip < NUM_IP22ZILOG; chip++) {
1091 if (!ip22zilog_chip_regs[chip]) {
1092 ip22zilog_chip_regs[chip] = rp = get_zs(chip);
1093
1094 up[(chip * 2) + 0].port.membase = (char *) &rp->channelB;
1095 up[(chip * 2) + 1].port.membase = (char *) &rp->channelA;
1096
1097 /* In theory mapbase is the physical address ... */
1098 up[(chip * 2) + 0].port.mapbase =
1099 (unsigned long) ioremap((unsigned long) &rp->channelB, 8);
1100 up[(chip * 2) + 1].port.mapbase =
1101 (unsigned long) ioremap((unsigned long) &rp->channelA, 8);
1102 }
1103
1104 /* Channel A */
1105 up[(chip * 2) + 0].port.iotype = UPIO_MEM;
1106 up[(chip * 2) + 0].port.irq = zilog_irq;
1107 up[(chip * 2) + 0].port.uartclk = ZS_CLOCK;
1108 up[(chip * 2) + 0].port.fifosize = 1;
1109 up[(chip * 2) + 0].port.ops = &ip22zilog_pops;
1110 up[(chip * 2) + 0].port.type = PORT_IP22ZILOG;
1111 up[(chip * 2) + 0].port.flags = 0;
1112 up[(chip * 2) + 0].port.line = (chip * 2) + 0;
1113 up[(chip * 2) + 0].flags = 0;
1114
1115 /* Channel B */
1116 up[(chip * 2) + 1].port.iotype = UPIO_MEM;
1117 up[(chip * 2) + 1].port.irq = zilog_irq;
1118 up[(chip * 2) + 1].port.uartclk = ZS_CLOCK;
1119 up[(chip * 2) + 1].port.fifosize = 1;
1120 up[(chip * 2) + 1].port.ops = &ip22zilog_pops;
1121 up[(chip * 2) + 1].port.type = PORT_IP22ZILOG;
1122 up[(chip * 2) + 1].port.line = (chip * 2) + 1;
1123 up[(chip * 2) + 1].flags |= IP22ZILOG_FLAG_IS_CHANNEL_A;
1124 }
1125
1126 for (channel = 0; channel < NUM_CHANNELS; channel++) {
1127 struct uart_ip22zilog_port *up = &ip22zilog_port_table[channel];
1128 int brg;
1129
1130 /* Normal serial TTY. */
1131 up->parity_mask = 0xff;
1132 up->curregs[R1] = EXT_INT_ENAB | INT_ALL_Rx | TxINT_ENAB;
1133 up->curregs[R4] = PAR_EVEN | X16CLK | SB1;
1134 up->curregs[R3] = RxENAB | Rx8;
1135 up->curregs[R5] = TxENAB | Tx8;
1136 up->curregs[R9] = NV | MIE;
1137 up->curregs[R10] = NRZ;
1138 up->curregs[R11] = TCBR | RCBR;
1139 brg = BPS_TO_BRG(9600, ZS_CLOCK / ZS_CLOCK_DIVISOR);
1140 up->curregs[R12] = (brg & 0xff);
1141 up->curregs[R13] = (brg >> 8) & 0xff;
1142 up->curregs[R14] = BRENAB;
1143 }
1144 }
1145
1146 static int __init ip22zilog_ports_init(void)
1147 {
1148 int ret;
1149
1150 printk(KERN_INFO "Serial: IP22 Zilog driver (%d chips).\n", NUM_IP22ZILOG);
1151
1152 ip22zilog_prepare();
1153
1154 if (request_irq(zilog_irq, ip22zilog_interrupt, 0,
1155 "IP22-Zilog", ip22zilog_irq_chain)) {
1156 panic("IP22-Zilog: Unable to register zs interrupt handler.\n");
1157 }
1158
1159 ret = uart_register_driver(&ip22zilog_reg);
1160 if (ret == 0) {
1161 int i;
1162
1163 for (i = 0; i < NUM_CHANNELS; i++) {
1164 struct uart_ip22zilog_port *up = &ip22zilog_port_table[i];
1165
1166 uart_add_one_port(&ip22zilog_reg, &up->port);
1167 }
1168 }
1169
1170 return ret;
1171 }
1172
1173 static int __init ip22zilog_init(void)
1174 {
1175 /* IP22 Zilog setup is hard coded, no probing to do. */
1176 ip22zilog_alloc_tables();
1177 ip22zilog_ports_init();
1178
1179 return 0;
1180 }
1181
1182 static void __exit ip22zilog_exit(void)
1183 {
1184 int i;
1185 struct uart_ip22zilog_port *up;
1186
1187 for (i = 0; i < NUM_CHANNELS; i++) {
1188 up = &ip22zilog_port_table[i];
1189
1190 uart_remove_one_port(&ip22zilog_reg, &up->port);
1191 }
1192
1193 /* Free IO mem */
1194 up = &ip22zilog_port_table[0];
1195 for (i = 0; i < NUM_IP22ZILOG; i++) {
1196 if (up[(i * 2) + 0].port.mapbase) {
1197 iounmap((void*)up[(i * 2) + 0].port.mapbase);
1198 up[(i * 2) + 0].port.mapbase = 0;
1199 }
1200 if (up[(i * 2) + 1].port.mapbase) {
1201 iounmap((void*)up[(i * 2) + 1].port.mapbase);
1202 up[(i * 2) + 1].port.mapbase = 0;
1203 }
1204 }
1205
1206 uart_unregister_driver(&ip22zilog_reg);
1207 }
1208
1209 module_init(ip22zilog_init);
1210 module_exit(ip22zilog_exit);
1211
1212 /* David wrote it but I'm to blame for the bugs ... */
1213 MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
1214 MODULE_DESCRIPTION("SGI Zilog serial port driver");
1215 MODULE_LICENSE("GPL");
Linux with added FPC-III support