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Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / drivers / tty / serial / meson_uart.c
blob69eeef9edfa509729e6efb4edac2a446098fe93a
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Based on meson_uart.c, by AMLOGIC, INC.
4 *
5 * Copyright (C) 2014 Carlo Caione <carlo@caione.org>
6 */
7
8 #include <linux/clk.h>
9 #include <linux/console.h>
10 #include <linux/delay.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/iopoll.h>
14 #include <linux/module.h>
15 #include <linux/kernel.h>
16 #include <linux/of.h>
17 #include <linux/platform_device.h>
18 #include <linux/serial.h>
19 #include <linux/serial_core.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22
23 /* Register offsets */
24 #define AML_UART_WFIFO 0x00
25 #define AML_UART_RFIFO 0x04
26 #define AML_UART_CONTROL 0x08
27 #define AML_UART_STATUS 0x0c
28 #define AML_UART_MISC 0x10
29 #define AML_UART_REG5 0x14
30
31 /* AML_UART_CONTROL bits */
32 #define AML_UART_TX_EN BIT(12)
33 #define AML_UART_RX_EN BIT(13)
34 #define AML_UART_TWO_WIRE_EN BIT(15)
35 #define AML_UART_STOP_BIT_LEN_MASK (0x03 << 16)
36 #define AML_UART_STOP_BIT_1SB (0x00 << 16)
37 #define AML_UART_STOP_BIT_2SB (0x01 << 16)
38 #define AML_UART_PARITY_TYPE BIT(18)
39 #define AML_UART_PARITY_EN BIT(19)
40 #define AML_UART_TX_RST BIT(22)
41 #define AML_UART_RX_RST BIT(23)
42 #define AML_UART_CLEAR_ERR BIT(24)
43 #define AML_UART_RX_INT_EN BIT(27)
44 #define AML_UART_TX_INT_EN BIT(28)
45 #define AML_UART_DATA_LEN_MASK (0x03 << 20)
46 #define AML_UART_DATA_LEN_8BIT (0x00 << 20)
47 #define AML_UART_DATA_LEN_7BIT (0x01 << 20)
48 #define AML_UART_DATA_LEN_6BIT (0x02 << 20)
49 #define AML_UART_DATA_LEN_5BIT (0x03 << 20)
50
51 /* AML_UART_STATUS bits */
52 #define AML_UART_PARITY_ERR BIT(16)
53 #define AML_UART_FRAME_ERR BIT(17)
54 #define AML_UART_TX_FIFO_WERR BIT(18)
55 #define AML_UART_RX_EMPTY BIT(20)
56 #define AML_UART_TX_FULL BIT(21)
57 #define AML_UART_TX_EMPTY BIT(22)
58 #define AML_UART_XMIT_BUSY BIT(25)
59 #define AML_UART_ERR (AML_UART_PARITY_ERR | \
60 AML_UART_FRAME_ERR | \
61 AML_UART_TX_FIFO_WERR)
62
63 /* AML_UART_MISC bits */
64 #define AML_UART_XMIT_IRQ(c) (((c) & 0xff) << 8)
65 #define AML_UART_RECV_IRQ(c) ((c) & 0xff)
66
67 /* AML_UART_REG5 bits */
68 #define AML_UART_BAUD_MASK 0x7fffff
69 #define AML_UART_BAUD_USE BIT(23)
70 #define AML_UART_BAUD_XTAL BIT(24)
71
72 #define AML_UART_PORT_NUM 12
73 #define AML_UART_PORT_OFFSET 6
74 #define AML_UART_DEV_NAME "ttyAML"
75
76 #define AML_UART_POLL_USEC 5
77 #define AML_UART_TIMEOUT_USEC 10000
78
79 static struct uart_driver meson_uart_driver;
80
81 static struct uart_port *meson_ports[AML_UART_PORT_NUM];
82
83 static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
84 {
85 }
86
87 static unsigned int meson_uart_get_mctrl(struct uart_port *port)
88 {
89 return TIOCM_CTS;
90 }
91
92 static unsigned int meson_uart_tx_empty(struct uart_port *port)
93 {
94 u32 val;
95
96 val = readl(port->membase + AML_UART_STATUS);
97 val &= (AML_UART_TX_EMPTY | AML_UART_XMIT_BUSY);
98 return (val == AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0;
99 }
100
101 static void meson_uart_stop_tx(struct uart_port *port)
102 {
103 u32 val;
104
105 val = readl(port->membase + AML_UART_CONTROL);
106 val &= ~AML_UART_TX_INT_EN;
107 writel(val, port->membase + AML_UART_CONTROL);
108 }
109
110 static void meson_uart_stop_rx(struct uart_port *port)
111 {
112 u32 val;
113
114 val = readl(port->membase + AML_UART_CONTROL);
115 val &= ~AML_UART_RX_EN;
116 writel(val, port->membase + AML_UART_CONTROL);
117 }
118
119 static void meson_uart_shutdown(struct uart_port *port)
120 {
121 unsigned long flags;
122 u32 val;
123
124 free_irq(port->irq, port);
125
126 spin_lock_irqsave(&port->lock, flags);
127
128 val = readl(port->membase + AML_UART_CONTROL);
129 val &= ~AML_UART_RX_EN;
130 val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
131 writel(val, port->membase + AML_UART_CONTROL);
132
133 spin_unlock_irqrestore(&port->lock, flags);
134 }
135
136 static void meson_uart_start_tx(struct uart_port *port)
137 {
138 struct circ_buf *xmit = &port->state->xmit;
139 unsigned int ch;
140 u32 val;
141
142 if (uart_tx_stopped(port)) {
143 meson_uart_stop_tx(port);
144 return;
145 }
146
147 while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
148 if (port->x_char) {
149 writel(port->x_char, port->membase + AML_UART_WFIFO);
150 port->icount.tx++;
151 port->x_char = 0;
152 continue;
153 }
154
155 if (uart_circ_empty(xmit))
156 break;
157
158 ch = xmit->buf[xmit->tail];
159 writel(ch, port->membase + AML_UART_WFIFO);
160 xmit->tail = (xmit->tail+1) & (SERIAL_XMIT_SIZE - 1);
161 port->icount.tx++;
162 }
163
164 if (!uart_circ_empty(xmit)) {
165 val = readl(port->membase + AML_UART_CONTROL);
166 val |= AML_UART_TX_INT_EN;
167 writel(val, port->membase + AML_UART_CONTROL);
168 }
169
170 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
171 uart_write_wakeup(port);
172 }
173
174 static void meson_receive_chars(struct uart_port *port)
175 {
176 struct tty_port *tport = &port->state->port;
177 char flag;
178 u32 ostatus, status, ch, mode;
179
180 do {
181 flag = TTY_NORMAL;
182 port->icount.rx++;
183 ostatus = status = readl(port->membase + AML_UART_STATUS);
184
185 if (status & AML_UART_ERR) {
186 if (status & AML_UART_TX_FIFO_WERR)
187 port->icount.overrun++;
188 else if (status & AML_UART_FRAME_ERR)
189 port->icount.frame++;
190 else if (status & AML_UART_PARITY_ERR)
191 port->icount.frame++;
192
193 mode = readl(port->membase + AML_UART_CONTROL);
194 mode |= AML_UART_CLEAR_ERR;
195 writel(mode, port->membase + AML_UART_CONTROL);
196
197 /* It doesn't clear to 0 automatically */
198 mode &= ~AML_UART_CLEAR_ERR;
199 writel(mode, port->membase + AML_UART_CONTROL);
200
201 status &= port->read_status_mask;
202 if (status & AML_UART_FRAME_ERR)
203 flag = TTY_FRAME;
204 else if (status & AML_UART_PARITY_ERR)
205 flag = TTY_PARITY;
206 }
207
208 ch = readl(port->membase + AML_UART_RFIFO);
209 ch &= 0xff;
210
211 if ((ostatus & AML_UART_FRAME_ERR) && (ch == 0)) {
212 port->icount.brk++;
213 flag = TTY_BREAK;
214 if (uart_handle_break(port))
215 continue;
216 }
217
218 if (uart_handle_sysrq_char(port, ch))
219 continue;
220
221 if ((status & port->ignore_status_mask) == 0)
222 tty_insert_flip_char(tport, ch, flag);
223
224 if (status & AML_UART_TX_FIFO_WERR)
225 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
226
227 } while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY));
228
229 spin_unlock(&port->lock);
230 tty_flip_buffer_push(tport);
231 spin_lock(&port->lock);
232 }
233
234 static irqreturn_t meson_uart_interrupt(int irq, void *dev_id)
235 {
236 struct uart_port *port = (struct uart_port *)dev_id;
237
238 spin_lock(&port->lock);
239
240 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY))
241 meson_receive_chars(port);
242
243 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
244 if (readl(port->membase + AML_UART_CONTROL) & AML_UART_TX_INT_EN)
245 meson_uart_start_tx(port);
246 }
247
248 spin_unlock(&port->lock);
249
250 return IRQ_HANDLED;
251 }
252
253 static const char *meson_uart_type(struct uart_port *port)
254 {
255 return (port->type == PORT_MESON) ? "meson_uart" : NULL;
256 }
257
258 static void meson_uart_reset(struct uart_port *port)
259 {
260 u32 val;
261
262 val = readl(port->membase + AML_UART_CONTROL);
263 val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR);
264 writel(val, port->membase + AML_UART_CONTROL);
265
266 val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR);
267 writel(val, port->membase + AML_UART_CONTROL);
268 }
269
270 static int meson_uart_startup(struct uart_port *port)
271 {
272 u32 val;
273 int ret = 0;
274
275 val = readl(port->membase + AML_UART_CONTROL);
276 val |= AML_UART_CLEAR_ERR;
277 writel(val, port->membase + AML_UART_CONTROL);
278 val &= ~AML_UART_CLEAR_ERR;
279 writel(val, port->membase + AML_UART_CONTROL);
280
281 val |= (AML_UART_RX_EN | AML_UART_TX_EN);
282 writel(val, port->membase + AML_UART_CONTROL);
283
284 val |= (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
285 writel(val, port->membase + AML_UART_CONTROL);
286
287 val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2));
288 writel(val, port->membase + AML_UART_MISC);
289
290 ret = request_irq(port->irq, meson_uart_interrupt, 0,
291 port->name, port);
292
293 return ret;
294 }
295
296 static void meson_uart_change_speed(struct uart_port *port, unsigned long baud)
297 {
298 u32 val;
299
300 while (!meson_uart_tx_empty(port))
301 cpu_relax();
302
303 if (port->uartclk == 24000000) {
304 val = ((port->uartclk / 3) / baud) - 1;
305 val |= AML_UART_BAUD_XTAL;
306 } else {
307 val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1;
308 }
309 val |= AML_UART_BAUD_USE;
310 writel(val, port->membase + AML_UART_REG5);
311 }
312
313 static void meson_uart_set_termios(struct uart_port *port,
314 struct ktermios *termios,
315 struct ktermios *old)
316 {
317 unsigned int cflags, iflags, baud;
318 unsigned long flags;
319 u32 val;
320
321 spin_lock_irqsave(&port->lock, flags);
322
323 cflags = termios->c_cflag;
324 iflags = termios->c_iflag;
325
326 val = readl(port->membase + AML_UART_CONTROL);
327
328 val &= ~AML_UART_DATA_LEN_MASK;
329 switch (cflags & CSIZE) {
330 case CS8:
331 val |= AML_UART_DATA_LEN_8BIT;
332 break;
333 case CS7:
334 val |= AML_UART_DATA_LEN_7BIT;
335 break;
336 case CS6:
337 val |= AML_UART_DATA_LEN_6BIT;
338 break;
339 case CS5:
340 val |= AML_UART_DATA_LEN_5BIT;
341 break;
342 }
343
344 if (cflags & PARENB)
345 val |= AML_UART_PARITY_EN;
346 else
347 val &= ~AML_UART_PARITY_EN;
348
349 if (cflags & PARODD)
350 val |= AML_UART_PARITY_TYPE;
351 else
352 val &= ~AML_UART_PARITY_TYPE;
353
354 val &= ~AML_UART_STOP_BIT_LEN_MASK;
355 if (cflags & CSTOPB)
356 val |= AML_UART_STOP_BIT_2SB;
357 else
358 val |= AML_UART_STOP_BIT_1SB;
359
360 if (cflags & CRTSCTS)
361 val &= ~AML_UART_TWO_WIRE_EN;
362 else
363 val |= AML_UART_TWO_WIRE_EN;
364
365 writel(val, port->membase + AML_UART_CONTROL);
366
367 baud = uart_get_baud_rate(port, termios, old, 50, 4000000);
368 meson_uart_change_speed(port, baud);
369
370 port->read_status_mask = AML_UART_TX_FIFO_WERR;
371 if (iflags & INPCK)
372 port->read_status_mask |= AML_UART_PARITY_ERR |
373 AML_UART_FRAME_ERR;
374
375 port->ignore_status_mask = 0;
376 if (iflags & IGNPAR)
377 port->ignore_status_mask |= AML_UART_PARITY_ERR |
378 AML_UART_FRAME_ERR;
379
380 uart_update_timeout(port, termios->c_cflag, baud);
381 spin_unlock_irqrestore(&port->lock, flags);
382 }
383
384 static int meson_uart_verify_port(struct uart_port *port,
385 struct serial_struct *ser)
386 {
387 int ret = 0;
388
389 if (port->type != PORT_MESON)
390 ret = -EINVAL;
391 if (port->irq != ser->irq)
392 ret = -EINVAL;
393 if (ser->baud_base < 9600)
394 ret = -EINVAL;
395 return ret;
396 }
397
398 static void meson_uart_release_port(struct uart_port *port)
399 {
400 devm_iounmap(port->dev, port->membase);
401 port->membase = NULL;
402 devm_release_mem_region(port->dev, port->mapbase, port->mapsize);
403 }
404
405 static int meson_uart_request_port(struct uart_port *port)
406 {
407 if (!devm_request_mem_region(port->dev, port->mapbase, port->mapsize,
408 dev_name(port->dev))) {
409 dev_err(port->dev, "Memory region busy\n");
410 return -EBUSY;
411 }
412
413 port->membase = devm_ioremap(port->dev, port->mapbase,
414 port->mapsize);
415 if (!port->membase)
416 return -ENOMEM;
417
418 return 0;
419 }
420
421 static void meson_uart_config_port(struct uart_port *port, int flags)
422 {
423 if (flags & UART_CONFIG_TYPE) {
424 port->type = PORT_MESON;
425 meson_uart_request_port(port);
426 }
427 }
428
429 #ifdef CONFIG_CONSOLE_POLL
430 /*
431 * Console polling routines for writing and reading from the uart while
432 * in an interrupt or debug context (i.e. kgdb).
433 */
434
435 static int meson_uart_poll_get_char(struct uart_port *port)
436 {
437 u32 c;
438 unsigned long flags;
439
440 spin_lock_irqsave(&port->lock, flags);
441
442 if (readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY)
443 c = NO_POLL_CHAR;
444 else
445 c = readl(port->membase + AML_UART_RFIFO);
446
447 spin_unlock_irqrestore(&port->lock, flags);
448
449 return c;
450 }
451
452 static void meson_uart_poll_put_char(struct uart_port *port, unsigned char c)
453 {
454 unsigned long flags;
455 u32 reg;
456 int ret;
457
458 spin_lock_irqsave(&port->lock, flags);
459
460 /* Wait until FIFO is empty or timeout */
461 ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg,
462 reg & AML_UART_TX_EMPTY,
463 AML_UART_POLL_USEC,
464 AML_UART_TIMEOUT_USEC);
465 if (ret == -ETIMEDOUT) {
466 dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n");
467 goto out;
468 }
469
470 /* Write the character */
471 writel(c, port->membase + AML_UART_WFIFO);
472
473 /* Wait until FIFO is empty or timeout */
474 ret = readl_poll_timeout_atomic(port->membase + AML_UART_STATUS, reg,
475 reg & AML_UART_TX_EMPTY,
476 AML_UART_POLL_USEC,
477 AML_UART_TIMEOUT_USEC);
478 if (ret == -ETIMEDOUT)
479 dev_err(port->dev, "Timeout waiting for UART TX EMPTY\n");
480
481 out:
482 spin_unlock_irqrestore(&port->lock, flags);
483 }
484
485 #endif /* CONFIG_CONSOLE_POLL */
486
487 static const struct uart_ops meson_uart_ops = {
488 .set_mctrl = meson_uart_set_mctrl,
489 .get_mctrl = meson_uart_get_mctrl,
490 .tx_empty = meson_uart_tx_empty,
491 .start_tx = meson_uart_start_tx,
492 .stop_tx = meson_uart_stop_tx,
493 .stop_rx = meson_uart_stop_rx,
494 .startup = meson_uart_startup,
495 .shutdown = meson_uart_shutdown,
496 .set_termios = meson_uart_set_termios,
497 .type = meson_uart_type,
498 .config_port = meson_uart_config_port,
499 .request_port = meson_uart_request_port,
500 .release_port = meson_uart_release_port,
501 .verify_port = meson_uart_verify_port,
502 #ifdef CONFIG_CONSOLE_POLL
503 .poll_get_char = meson_uart_poll_get_char,
504 .poll_put_char = meson_uart_poll_put_char,
505 #endif
506 };
507
508 #ifdef CONFIG_SERIAL_MESON_CONSOLE
509 static void meson_uart_enable_tx_engine(struct uart_port *port)
510 {
511 u32 val;
512
513 val = readl(port->membase + AML_UART_CONTROL);
514 val |= AML_UART_TX_EN;
515 writel(val, port->membase + AML_UART_CONTROL);
516 }
517
518 static void meson_console_putchar(struct uart_port *port, int ch)
519 {
520 if (!port->membase)
521 return;
522
523 while (readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)
524 cpu_relax();
525 writel(ch, port->membase + AML_UART_WFIFO);
526 }
527
528 static void meson_serial_port_write(struct uart_port *port, const char *s,
529 u_int count)
530 {
531 unsigned long flags;
532 int locked;
533 u32 val, tmp;
534
535 local_irq_save(flags);
536 if (port->sysrq) {
537 locked = 0;
538 } else if (oops_in_progress) {
539 locked = spin_trylock(&port->lock);
540 } else {
541 spin_lock(&port->lock);
542 locked = 1;
543 }
544
545 val = readl(port->membase + AML_UART_CONTROL);
546 tmp = val & ~(AML_UART_TX_INT_EN | AML_UART_RX_INT_EN);
547 writel(tmp, port->membase + AML_UART_CONTROL);
548
549 uart_console_write(port, s, count, meson_console_putchar);
550 writel(val, port->membase + AML_UART_CONTROL);
551
552 if (locked)
553 spin_unlock(&port->lock);
554 local_irq_restore(flags);
555 }
556
557 static void meson_serial_console_write(struct console *co, const char *s,
558 u_int count)
559 {
560 struct uart_port *port;
561
562 port = meson_ports[co->index];
563 if (!port)
564 return;
565
566 meson_serial_port_write(port, s, count);
567 }
568
569 static int meson_serial_console_setup(struct console *co, char *options)
570 {
571 struct uart_port *port;
572 int baud = 115200;
573 int bits = 8;
574 int parity = 'n';
575 int flow = 'n';
576
577 if (co->index < 0 || co->index >= AML_UART_PORT_NUM)
578 return -EINVAL;
579
580 port = meson_ports[co->index];
581 if (!port || !port->membase)
582 return -ENODEV;
583
584 meson_uart_enable_tx_engine(port);
585
586 if (options)
587 uart_parse_options(options, &baud, &parity, &bits, &flow);
588
589 return uart_set_options(port, co, baud, parity, bits, flow);
590 }
591
592 static struct console meson_serial_console = {
593 .name = AML_UART_DEV_NAME,
594 .write = meson_serial_console_write,
595 .device = uart_console_device,
596 .setup = meson_serial_console_setup,
597 .flags = CON_PRINTBUFFER,
598 .index = -1,
599 .data = &meson_uart_driver,
600 };
601
602 static int __init meson_serial_console_init(void)
603 {
604 register_console(&meson_serial_console);
605 return 0;
606 }
607
608 static void meson_serial_early_console_write(struct console *co,
609 const char *s,
610 u_int count)
611 {
612 struct earlycon_device *dev = co->data;
613
614 meson_serial_port_write(&dev->port, s, count);
615 }
616
617 static int __init
618 meson_serial_early_console_setup(struct earlycon_device *device, const char *opt)
619 {
620 if (!device->port.membase)
621 return -ENODEV;
622
623 meson_uart_enable_tx_engine(&device->port);
624 device->con->write = meson_serial_early_console_write;
625 return 0;
626 }
627 /* Legacy bindings, should be removed when no more used */
628 OF_EARLYCON_DECLARE(meson, "amlogic,meson-uart",
629 meson_serial_early_console_setup);
630 /* Stable bindings */
631 OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart",
632 meson_serial_early_console_setup);
633
634 #define MESON_SERIAL_CONSOLE (&meson_serial_console)
635 #else
636 static int __init meson_serial_console_init(void) {
637 return 0;
638 }
639 #define MESON_SERIAL_CONSOLE NULL
640 #endif
641
642 static struct uart_driver meson_uart_driver = {
643 .owner = THIS_MODULE,
644 .driver_name = "meson_uart",
645 .dev_name = AML_UART_DEV_NAME,
646 .nr = AML_UART_PORT_NUM,
647 .cons = MESON_SERIAL_CONSOLE,
648 };
649
650 static inline struct clk *meson_uart_probe_clock(struct device *dev,
651 const char *id)
652 {
653 struct clk *clk = NULL;
654 int ret;
655
656 clk = devm_clk_get(dev, id);
657 if (IS_ERR(clk))
658 return clk;
659
660 ret = clk_prepare_enable(clk);
661 if (ret) {
662 dev_err(dev, "couldn't enable clk\n");
663 return ERR_PTR(ret);
664 }
665
666 devm_add_action_or_reset(dev,
667 (void(*)(void *))clk_disable_unprepare,
668 clk);
669
670 return clk;
671 }
672
673 /*
674 * This function gets clocks in the legacy non-stable DT bindings.
675 * This code will be remove once all the platforms switch to the
676 * new DT bindings.
677 */
678 static int meson_uart_probe_clocks_legacy(struct platform_device *pdev,
679 struct uart_port *port)
680 {
681 struct clk *clk = NULL;
682
683 clk = meson_uart_probe_clock(&pdev->dev, NULL);
684 if (IS_ERR(clk))
685 return PTR_ERR(clk);
686
687 port->uartclk = clk_get_rate(clk);
688
689 return 0;
690 }
691
692 static int meson_uart_probe_clocks(struct platform_device *pdev,
693 struct uart_port *port)
694 {
695 struct clk *clk_xtal = NULL;
696 struct clk *clk_pclk = NULL;
697 struct clk *clk_baud = NULL;
698
699 clk_pclk = meson_uart_probe_clock(&pdev->dev, "pclk");
700 if (IS_ERR(clk_pclk))
701 return PTR_ERR(clk_pclk);
702
703 clk_xtal = meson_uart_probe_clock(&pdev->dev, "xtal");
704 if (IS_ERR(clk_xtal))
705 return PTR_ERR(clk_xtal);
706
707 clk_baud = meson_uart_probe_clock(&pdev->dev, "baud");
708 if (IS_ERR(clk_baud))
709 return PTR_ERR(clk_baud);
710
711 port->uartclk = clk_get_rate(clk_baud);
712
713 return 0;
714 }
715
716 static int meson_uart_probe(struct platform_device *pdev)
717 {
718 struct resource *res_mem, *res_irq;
719 struct uart_port *port;
720 int ret = 0;
721 int id = -1;
722
723 if (pdev->dev.of_node)
724 pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
725
726 if (pdev->id < 0) {
727 for (id = AML_UART_PORT_OFFSET; id < AML_UART_PORT_NUM; id++) {
728 if (!meson_ports[id]) {
729 pdev->id = id;
730 break;
731 }
732 }
733 }
734
735 if (pdev->id < 0 || pdev->id >= AML_UART_PORT_NUM)
736 return -EINVAL;
737
738 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
739 if (!res_mem)
740 return -ENODEV;
741
742 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
743 if (!res_irq)
744 return -ENODEV;
745
746 if (meson_ports[pdev->id]) {
747 dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
748 return -EBUSY;
749 }
750
751 port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL);
752 if (!port)
753 return -ENOMEM;
754
755 /* Use legacy way until all platforms switch to new bindings */
756 if (of_device_is_compatible(pdev->dev.of_node, "amlogic,meson-uart"))
757 ret = meson_uart_probe_clocks_legacy(pdev, port);
758 else
759 ret = meson_uart_probe_clocks(pdev, port);
760
761 if (ret)
762 return ret;
763
764 port->iotype = UPIO_MEM;
765 port->mapbase = res_mem->start;
766 port->mapsize = resource_size(res_mem);
767 port->irq = res_irq->start;
768 port->flags = UPF_BOOT_AUTOCONF | UPF_LOW_LATENCY;
769 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_MESON_CONSOLE);
770 port->dev = &pdev->dev;
771 port->line = pdev->id;
772 port->type = PORT_MESON;
773 port->x_char = 0;
774 port->ops = &meson_uart_ops;
775 port->fifosize = 64;
776
777 meson_ports[pdev->id] = port;
778 platform_set_drvdata(pdev, port);
779
780 /* reset port before registering (and possibly registering console) */
781 if (meson_uart_request_port(port) >= 0) {
782 meson_uart_reset(port);
783 meson_uart_release_port(port);
784 }
785
786 ret = uart_add_one_port(&meson_uart_driver, port);
787 if (ret)
788 meson_ports[pdev->id] = NULL;
789
790 return ret;
791 }
792
793 static int meson_uart_remove(struct platform_device *pdev)
794 {
795 struct uart_port *port;
796
797 port = platform_get_drvdata(pdev);
798 uart_remove_one_port(&meson_uart_driver, port);
799 meson_ports[pdev->id] = NULL;
800
801 return 0;
802 }
803
804 static const struct of_device_id meson_uart_dt_match[] = {
805 /* Legacy bindings, should be removed when no more used */
806 { .compatible = "amlogic,meson-uart" },
807 /* Stable bindings */
808 { .compatible = "amlogic,meson6-uart" },
809 { .compatible = "amlogic,meson8-uart" },
810 { .compatible = "amlogic,meson8b-uart" },
811 { .compatible = "amlogic,meson-gx-uart" },
812 { /* sentinel */ },
813 };
814 MODULE_DEVICE_TABLE(of, meson_uart_dt_match);
815
816 static struct platform_driver meson_uart_platform_driver = {
817 .probe = meson_uart_probe,
818 .remove = meson_uart_remove,
819 .driver = {
820 .name = "meson_uart",
821 .of_match_table = meson_uart_dt_match,
822 },
823 };
824
825 static int __init meson_uart_init(void)
826 {
827 int ret;
828
829 ret = meson_serial_console_init();
830 if (ret)
831 return ret;
832
833 ret = uart_register_driver(&meson_uart_driver);
834 if (ret)
835 return ret;
836
837 ret = platform_driver_register(&meson_uart_platform_driver);
838 if (ret)
839 uart_unregister_driver(&meson_uart_driver);
840
841 return ret;
842 }
843
844 static void __exit meson_uart_exit(void)
845 {
846 platform_driver_unregister(&meson_uart_platform_driver);
847 uart_unregister_driver(&meson_uart_driver);
848 }
849
850 module_init(meson_uart_init);
851 module_exit(meson_uart_exit);
852
853 MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
854 MODULE_DESCRIPTION("Amlogic Meson serial port driver");
855 MODULE_LICENSE("GPL v2");
Linux with added FPC-III support