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1/*
2 * Based on meson_uart.c, by AMLOGIC, INC.
3 *
4 * Copyright (C) 2014 Carlo Caione <carlo@caione.org>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 */
16
17#include <linux/clk.h>
18#include <linux/console.h>
19#include <linux/delay.h>
20#include <linux/init.h>
21#include <linux/io.h>
22#include <linux/module.h>
23#include <linux/kernel.h>
24#include <linux/of.h>
25#include <linux/platform_device.h>
26#include <linux/serial.h>
27#include <linux/serial_core.h>
28#include <linux/tty.h>
29#include <linux/tty_flip.h>
30
31/* Register offsets */
32#define AML_UART_WFIFO 0x00
33#define AML_UART_RFIFO 0x04
34#define AML_UART_CONTROL 0x08
35#define AML_UART_STATUS 0x0c
36#define AML_UART_MISC 0x10
37#define AML_UART_REG5 0x14
38
39/* AML_UART_CONTROL bits */
40#define AML_UART_TX_EN BIT(12)
41#define AML_UART_RX_EN BIT(13)
42#define AML_UART_TX_RST BIT(22)
43#define AML_UART_RX_RST BIT(23)
44#define AML_UART_CLR_ERR BIT(24)
45#define AML_UART_RX_INT_EN BIT(27)
46#define AML_UART_TX_INT_EN BIT(28)
47#define AML_UART_DATA_LEN_MASK (0x03 << 20)
48#define AML_UART_DATA_LEN_8BIT (0x00 << 20)
49#define AML_UART_DATA_LEN_7BIT (0x01 << 20)
50#define AML_UART_DATA_LEN_6BIT (0x02 << 20)
51#define AML_UART_DATA_LEN_5BIT (0x03 << 20)
52
53/* AML_UART_STATUS bits */
54#define AML_UART_PARITY_ERR BIT(16)
55#define AML_UART_FRAME_ERR BIT(17)
56#define AML_UART_TX_FIFO_WERR BIT(18)
57#define AML_UART_RX_EMPTY BIT(20)
58#define AML_UART_TX_FULL BIT(21)
59#define AML_UART_TX_EMPTY BIT(22)
60#define AML_UART_XMIT_BUSY BIT(25)
61#define AML_UART_ERR (AML_UART_PARITY_ERR | \
62 AML_UART_FRAME_ERR | \
63 AML_UART_TX_FIFO_WERR)
64
65/* AML_UART_CONTROL bits */
66#define AML_UART_TWO_WIRE_EN BIT(15)
67#define AML_UART_PARITY_TYPE BIT(18)
68#define AML_UART_PARITY_EN BIT(19)
69#define AML_UART_CLEAR_ERR BIT(24)
70#define AML_UART_STOP_BIN_LEN_MASK (0x03 << 16)
71#define AML_UART_STOP_BIN_1SB (0x00 << 16)
72#define AML_UART_STOP_BIN_2SB (0x01 << 16)
73
74/* AML_UART_MISC bits */
75#define AML_UART_XMIT_IRQ(c) (((c) & 0xff) << 8)
76#define AML_UART_RECV_IRQ(c) ((c) & 0xff)
77
78/* AML_UART_REG5 bits */
79#define AML_UART_BAUD_MASK 0x7fffff
80#define AML_UART_BAUD_USE BIT(23)
81#define AML_UART_BAUD_XTAL BIT(24)
82
83#define AML_UART_PORT_NUM 6
84#define AML_UART_DEV_NAME "ttyAML"
85
86
87static struct uart_driver meson_uart_driver;
88
89static struct uart_port *meson_ports[AML_UART_PORT_NUM];
90
91static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
92{
93}
94
95static unsigned int meson_uart_get_mctrl(struct uart_port *port)
96{
97 return TIOCM_CTS;
98}
99
100static unsigned int meson_uart_tx_empty(struct uart_port *port)
101{
102 u32 val;
103
104 val = readl(port->membase + AML_UART_STATUS);
105 val &= (AML_UART_TX_EMPTY | AML_UART_XMIT_BUSY);
106 return (val == AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0;
107}
108
109static void meson_uart_stop_tx(struct uart_port *port)
110{
111 u32 val;
112
113 val = readl(port->membase + AML_UART_CONTROL);
114 val &= ~AML_UART_TX_INT_EN;
115 writel(val, port->membase + AML_UART_CONTROL);
116}
117
118static void meson_uart_stop_rx(struct uart_port *port)
119{
120 u32 val;
121
122 val = readl(port->membase + AML_UART_CONTROL);
123 val &= ~AML_UART_RX_EN;
124 writel(val, port->membase + AML_UART_CONTROL);
125}
126
127static void meson_uart_shutdown(struct uart_port *port)
128{
129 unsigned long flags;
130 u32 val;
131
132 free_irq(port->irq, port);
133
134 spin_lock_irqsave(&port->lock, flags);
135
136 val = readl(port->membase + AML_UART_CONTROL);
137 val &= ~AML_UART_RX_EN;
138 val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
139 writel(val, port->membase + AML_UART_CONTROL);
140
141 spin_unlock_irqrestore(&port->lock, flags);
142}
143
144static void meson_uart_start_tx(struct uart_port *port)
145{
146 struct circ_buf *xmit = &port->state->xmit;
147 unsigned int ch;
148 u32 val;
149
150 if (uart_tx_stopped(port)) {
151 meson_uart_stop_tx(port);
152 return;
153 }
154
155 while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
156 if (port->x_char) {
157 writel(port->x_char, port->membase + AML_UART_WFIFO);
158 port->icount.tx++;
159 port->x_char = 0;
160 continue;
161 }
162
163 if (uart_circ_empty(xmit))
164 break;
165
166 ch = xmit->buf[xmit->tail];
167 writel(ch, port->membase + AML_UART_WFIFO);
168 xmit->tail = (xmit->tail+1) & (SERIAL_XMIT_SIZE - 1);
169 port->icount.tx++;
170 }
171
172 if (!uart_circ_empty(xmit)) {
173 val = readl(port->membase + AML_UART_CONTROL);
174 val |= AML_UART_TX_INT_EN;
175 writel(val, port->membase + AML_UART_CONTROL);
176 }
177
178 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
179 uart_write_wakeup(port);
180}
181
182static void meson_receive_chars(struct uart_port *port)
183{
184 struct tty_port *tport = &port->state->port;
185 char flag;
186 u32 status, ch, mode;
187
188 do {
189 flag = TTY_NORMAL;
190 port->icount.rx++;
191 status = readl(port->membase + AML_UART_STATUS);
192
193 if (status & AML_UART_ERR) {
194 if (status & AML_UART_TX_FIFO_WERR)
195 port->icount.overrun++;
196 else if (status & AML_UART_FRAME_ERR)
197 port->icount.frame++;
198 else if (status & AML_UART_PARITY_ERR)
199 port->icount.frame++;
200
201 mode = readl(port->membase + AML_UART_CONTROL);
202 mode |= AML_UART_CLEAR_ERR;
203 writel(mode, port->membase + AML_UART_CONTROL);
204
205 /* It doesn't clear to 0 automatically */
206 mode &= ~AML_UART_CLEAR_ERR;
207 writel(mode, port->membase + AML_UART_CONTROL);
208
209 status &= port->read_status_mask;
210 if (status & AML_UART_FRAME_ERR)
211 flag = TTY_FRAME;
212 else if (status & AML_UART_PARITY_ERR)
213 flag = TTY_PARITY;
214 }
215
216 ch = readl(port->membase + AML_UART_RFIFO);
217 ch &= 0xff;
218
219 if ((status & port->ignore_status_mask) == 0)
220 tty_insert_flip_char(tport, ch, flag);
221
222 if (status & AML_UART_TX_FIFO_WERR)
223 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
224
225 } while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY));
226
227 spin_unlock(&port->lock);
228 tty_flip_buffer_push(tport);
229 spin_lock(&port->lock);
230}
231
232static irqreturn_t meson_uart_interrupt(int irq, void *dev_id)
233{
234 struct uart_port *port = (struct uart_port *)dev_id;
235
236 spin_lock(&port->lock);
237
238 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY))
239 meson_receive_chars(port);
240
241 if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
242 if (readl(port->membase + AML_UART_CONTROL) & AML_UART_TX_INT_EN)
243 meson_uart_start_tx(port);
244 }
245
246 spin_unlock(&port->lock);
247
248 return IRQ_HANDLED;
249}
250
251static const char *meson_uart_type(struct uart_port *port)
252{
253 return (port->type == PORT_MESON) ? "meson_uart" : NULL;
254}
255
256static void meson_uart_reset(struct uart_port *port)
257{
258 u32 val;
259
260 val = readl(port->membase + AML_UART_CONTROL);
261 val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
262 writel(val, port->membase + AML_UART_CONTROL);
263
264 val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLR_ERR);
265 writel(val, port->membase + AML_UART_CONTROL);
266}
267
268static int meson_uart_startup(struct uart_port *port)
269{
270 u32 val;
271 int ret = 0;
272
273 val = readl(port->membase + AML_UART_CONTROL);
274 val |= AML_UART_CLR_ERR;
275 writel(val, port->membase + AML_UART_CONTROL);
276 val &= ~AML_UART_CLR_ERR;
277 writel(val, port->membase + AML_UART_CONTROL);
278
279 val |= (AML_UART_RX_EN | AML_UART_TX_EN);
280 writel(val, port->membase + AML_UART_CONTROL);
281
282 val |= (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
283 writel(val, port->membase + AML_UART_CONTROL);
284
285 val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2));
286 writel(val, port->membase + AML_UART_MISC);
287
288 ret = request_irq(port->irq, meson_uart_interrupt, 0,
289 meson_uart_type(port), port);
290
291 return ret;
292}
293
294static void meson_uart_change_speed(struct uart_port *port, unsigned long baud)
295{
296 u32 val;
297
298 while (!meson_uart_tx_empty(port))
299 cpu_relax();
300
301 val = readl(port->membase + AML_UART_REG5);
302 val &= ~AML_UART_BAUD_MASK;
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_BIN_LEN_MASK;
355 if (cflags & CSTOPB)
356 val |= AML_UART_STOP_BIN_2SB;
357 else
358 val &= ~AML_UART_STOP_BIN_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, 9600, 115200);
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 int meson_uart_res_size(struct uart_port *port)
399{
400 struct platform_device *pdev = to_platform_device(port->dev);
401 struct resource *res;
402
403 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
404 if (!res) {
405 dev_err(port->dev, "cannot obtain I/O memory region");
406 return -ENODEV;
407 }
408
409 return resource_size(res);
410}
411
412static void meson_uart_release_port(struct uart_port *port)
413{
414 int size = meson_uart_res_size(port);
415
416 if (port->flags & UPF_IOREMAP) {
417 devm_release_mem_region(port->dev, port->mapbase, size);
418 devm_iounmap(port->dev, port->membase);
419 port->membase = NULL;
420 }
421}
422
423static int meson_uart_request_port(struct uart_port *port)
424{
425 int size = meson_uart_res_size(port);
426
427 if (size < 0)
428 return size;
429
430 if (!devm_request_mem_region(port->dev, port->mapbase, size,
431 dev_name(port->dev))) {
432 dev_err(port->dev, "Memory region busy\n");
433 return -EBUSY;
434 }
435
436 if (port->flags & UPF_IOREMAP) {
437 port->membase = devm_ioremap_nocache(port->dev,
438 port->mapbase,
439 size);
440 if (port->membase == NULL)
441 return -ENOMEM;
442 }
443
444 return 0;
445}
446
447static void meson_uart_config_port(struct uart_port *port, int flags)
448{
449 if (flags & UART_CONFIG_TYPE) {
450 port->type = PORT_MESON;
451 meson_uart_request_port(port);
452 }
453}
454
455static struct uart_ops meson_uart_ops = {
456 .set_mctrl = meson_uart_set_mctrl,
457 .get_mctrl = meson_uart_get_mctrl,
458 .tx_empty = meson_uart_tx_empty,
459 .start_tx = meson_uart_start_tx,
460 .stop_tx = meson_uart_stop_tx,
461 .stop_rx = meson_uart_stop_rx,
462 .startup = meson_uart_startup,
463 .shutdown = meson_uart_shutdown,
464 .set_termios = meson_uart_set_termios,
465 .type = meson_uart_type,
466 .config_port = meson_uart_config_port,
467 .request_port = meson_uart_request_port,
468 .release_port = meson_uart_release_port,
469 .verify_port = meson_uart_verify_port,
470};
471
472#ifdef CONFIG_SERIAL_MESON_CONSOLE
473
474static void meson_console_putchar(struct uart_port *port, int ch)
475{
476 if (!port->membase)
477 return;
478
479 while (readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)
480 cpu_relax();
481 writel(ch, port->membase + AML_UART_WFIFO);
482}
483
484static void meson_serial_port_write(struct uart_port *port, const char *s,
485 u_int count)
486{
487 unsigned long flags;
488 int locked;
489 u32 val, tmp;
490
491 local_irq_save(flags);
492 if (port->sysrq) {
493 locked = 0;
494 } else if (oops_in_progress) {
495 locked = spin_trylock(&port->lock);
496 } else {
497 spin_lock(&port->lock);
498 locked = 1;
499 }
500
501 val = readl(port->membase + AML_UART_CONTROL);
502 val |= AML_UART_TX_EN;
503 tmp = val & ~(AML_UART_TX_INT_EN | AML_UART_RX_INT_EN);
504 writel(tmp, port->membase + AML_UART_CONTROL);
505
506 uart_console_write(port, s, count, meson_console_putchar);
507 writel(val, port->membase + AML_UART_CONTROL);
508
509 if (locked)
510 spin_unlock(&port->lock);
511 local_irq_restore(flags);
512}
513
514static void meson_serial_console_write(struct console *co, const char *s,
515 u_int count)
516{
517 struct uart_port *port;
518
519 port = meson_ports[co->index];
520 if (!port)
521 return;
522
523 meson_serial_port_write(port, s, count);
524}
525
526static int meson_serial_console_setup(struct console *co, char *options)
527{
528 struct uart_port *port;
529 int baud = 115200;
530 int bits = 8;
531 int parity = 'n';
532 int flow = 'n';
533
534 if (co->index < 0 || co->index >= AML_UART_PORT_NUM)
535 return -EINVAL;
536
537 port = meson_ports[co->index];
538 if (!port || !port->membase)
539 return -ENODEV;
540
541 if (options)
542 uart_parse_options(options, &baud, &parity, &bits, &flow);
543
544 return uart_set_options(port, co, baud, parity, bits, flow);
545}
546
547static struct console meson_serial_console = {
548 .name = AML_UART_DEV_NAME,
549 .write = meson_serial_console_write,
550 .device = uart_console_device,
551 .setup = meson_serial_console_setup,
552 .flags = CON_PRINTBUFFER,
553 .index = -1,
554 .data = &meson_uart_driver,
555};
556
557static int __init meson_serial_console_init(void)
558{
559 register_console(&meson_serial_console);
560 return 0;
561}
562console_initcall(meson_serial_console_init);
563
564static void meson_serial_early_console_write(struct console *co,
565 const char *s,
566 u_int count)
567{
568 struct earlycon_device *dev = co->data;
569
570 meson_serial_port_write(&dev->port, s, count);
571}
572
573static int __init
574meson_serial_early_console_setup(struct earlycon_device *device, const char *opt)
575{
576 if (!device->port.membase)
577 return -ENODEV;
578
579 device->con->write = meson_serial_early_console_write;
580 return 0;
581}
582OF_EARLYCON_DECLARE(meson, "amlogic,meson-uart",
583 meson_serial_early_console_setup);
584
585#define MESON_SERIAL_CONSOLE (&meson_serial_console)
586#else
587#define MESON_SERIAL_CONSOLE NULL
588#endif
589
590static struct uart_driver meson_uart_driver = {
591 .owner = THIS_MODULE,
592 .driver_name = "meson_uart",
593 .dev_name = AML_UART_DEV_NAME,
594 .nr = AML_UART_PORT_NUM,
595 .cons = MESON_SERIAL_CONSOLE,
596};
597
598static int meson_uart_probe(struct platform_device *pdev)
599{
600 struct resource *res_mem, *res_irq;
601 struct uart_port *port;
602 struct clk *clk;
603 int ret = 0;
604
605 if (pdev->dev.of_node)
606 pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
607
608 if (pdev->id < 0 || pdev->id >= AML_UART_PORT_NUM)
609 return -EINVAL;
610
611 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
612 if (!res_mem)
613 return -ENODEV;
614
615 res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
616 if (!res_irq)
617 return -ENODEV;
618
619 if (meson_ports[pdev->id]) {
620 dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
621 return -EBUSY;
622 }
623
624 port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL);
625 if (!port)
626 return -ENOMEM;
627
628 clk = clk_get(&pdev->dev, NULL);
629 if (IS_ERR(clk))
630 return PTR_ERR(clk);
631
632 port->uartclk = clk_get_rate(clk);
633 port->iotype = UPIO_MEM;
634 port->mapbase = res_mem->start;
635 port->irq = res_irq->start;
636 port->flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP | UPF_LOW_LATENCY;
637 port->dev = &pdev->dev;
638 port->line = pdev->id;
639 port->type = PORT_MESON;
640 port->x_char = 0;
641 port->ops = &meson_uart_ops;
642 port->fifosize = 64;
643
644 meson_ports[pdev->id] = port;
645 platform_set_drvdata(pdev, port);
646
647 /* reset port before registering (and possibly registering console) */
648 if (meson_uart_request_port(port) >= 0) {
649 meson_uart_reset(port);
650 meson_uart_release_port(port);
651 }
652
653 ret = uart_add_one_port(&meson_uart_driver, port);
654 if (ret)
655 meson_ports[pdev->id] = NULL;
656
657 return ret;
658}
659
660static int meson_uart_remove(struct platform_device *pdev)
661{
662 struct uart_port *port;
663
664 port = platform_get_drvdata(pdev);
665 uart_remove_one_port(&meson_uart_driver, port);
666 meson_ports[pdev->id] = NULL;
667
668 return 0;
669}
670
671
672static const struct of_device_id meson_uart_dt_match[] = {
673 { .compatible = "amlogic,meson-uart" },
674 { /* sentinel */ },
675};
676MODULE_DEVICE_TABLE(of, meson_uart_dt_match);
677
678static struct platform_driver meson_uart_platform_driver = {
679 .probe = meson_uart_probe,
680 .remove = meson_uart_remove,
681 .driver = {
682 .name = "meson_uart",
683 .of_match_table = meson_uart_dt_match,
684 },
685};
686
687static int __init meson_uart_init(void)
688{
689 int ret;
690
691 ret = uart_register_driver(&meson_uart_driver);
692 if (ret)
693 return ret;
694
695 ret = platform_driver_register(&meson_uart_platform_driver);
696 if (ret)
697 uart_unregister_driver(&meson_uart_driver);
698
699 return ret;
700}
701
702static void __exit meson_uart_exit(void)
703{
704 platform_driver_unregister(&meson_uart_platform_driver);
705 uart_unregister_driver(&meson_uart_driver);
706}
707
708module_init(meson_uart_init);
709module_exit(meson_uart_exit);
710
711MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
712MODULE_DESCRIPTION("Amlogic Meson serial port driver");
713MODULE_LICENSE("GPL v2");