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