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ar71xx: add 2.6.39 support
[openwrt.git] / target / linux / ar71xx / files / drivers / serial / ar933x_uart.c
1 /*
2 * Atheros AR933X SoC built-in UART driver
3 *
4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>
5 *
6 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 *
8 * This program is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 as published
10 * by the Free Software Foundation.
11 */
12
13 #include <linux/module.h>
14 #include <linux/ioport.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/sysrq.h>
18 #include <linux/delay.h>
19 #include <linux/platform_device.h>
20 #include <linux/tty.h>
21 #include <linux/tty_flip.h>
22 #include <linux/serial_core.h>
23 #include <linux/serial.h>
24 #include <linux/slab.h>
25 #include <linux/io.h>
26 #include <linux/irq.h>
27
28 #include <asm/mach-ar71xx/ar933x_uart.h>
29 #include <asm/mach-ar71xx/ar933x_uart_platform.h>
30
31 #define DRIVER_NAME "ar933x-uart"
32
33 #define AR933X_DUMMY_STATUS_RD 0x01
34
35 static struct uart_driver ar933x_uart_driver;
36
37 struct ar933x_uart_port {
38 struct uart_port port;
39 unsigned int ier; /* shadow Interrupt Enable Register */
40 };
41
42 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
43 int offset)
44 {
45 return readl(up->port.membase + offset);
46 }
47
48 static inline void ar933x_uart_write(struct ar933x_uart_port *up,
49 int offset, unsigned int value)
50 {
51 writel(value, up->port.membase + offset);
52 }
53
54 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
55 unsigned int offset,
56 unsigned int mask,
57 unsigned int val)
58 {
59 unsigned int t;
60
61 t = ar933x_uart_read(up, offset);
62 t &= ~mask;
63 t |= val;
64 ar933x_uart_write(up, offset, t);
65 }
66
67 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
68 unsigned int offset,
69 unsigned int val)
70 {
71 ar933x_uart_rmw(up, offset, 0, val);
72 }
73
74 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
75 unsigned int offset,
76 unsigned int val)
77 {
78 ar933x_uart_rmw(up, offset, val, 0);
79 }
80
81 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
82 {
83 up->ier |= AR933X_UART_INT_TX_EMPTY;
84 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
85 }
86
87 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
88 {
89 up->ier &= ~AR933X_UART_INT_TX_EMPTY;
90 ar933x_uart_write(up, AR933X_UART_INT_EN_REG,up->ier);
91 }
92
93 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
94 {
95 unsigned int rdata;
96
97 rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
98 rdata |= AR933X_UART_DATA_TX_CSR;
99 ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
100 }
101
102 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
103 {
104 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
105 unsigned long flags;
106 unsigned int rdata;
107
108 spin_lock_irqsave(&up->port.lock, flags);
109 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
110 spin_unlock_irqrestore(&up->port.lock, flags);
111
112 return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
113 }
114
115 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
116 {
117 return TIOCM_CAR;
118 }
119
120 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
121 {
122 }
123
124 static void ar933x_uart_start_tx(struct uart_port *port)
125 {
126 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
127
128 ar933x_uart_start_tx_interrupt(up);
129 }
130
131 static void ar933x_uart_stop_tx(struct uart_port *port)
132 {
133 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
134
135 ar933x_uart_stop_tx_interrupt(up);
136 }
137
138 static void ar933x_uart_stop_rx(struct uart_port *port)
139 {
140 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
141
142 up->ier &= ~AR933X_UART_INT_RX_VALID;
143 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
144 }
145
146 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
147 {
148 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
149 unsigned long flags;
150
151 spin_lock_irqsave(&up->port.lock, flags);
152 if (break_state == -1)
153 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
154 AR933X_UART_CS_TX_BREAK);
155 else
156 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
157 AR933X_UART_CS_TX_BREAK);
158 spin_unlock_irqrestore(&up->port.lock, flags);
159 }
160
161 static void ar933x_uart_enable_ms(struct uart_port *port)
162 {
163 }
164
165 static void ar933x_uart_set_termios(struct uart_port *port,
166 struct ktermios *new,
167 struct ktermios *old)
168 {
169 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
170 unsigned int cs;
171 unsigned long flags;
172 unsigned int baud, scale;
173
174 /* Only CS8 is supported */
175 new->c_cflag &= ~CSIZE;
176 new->c_cflag |= CS8;
177
178 /* Only one stop bit is supported */
179 new->c_cflag &= ~CSTOPB;
180
181 cs = 0;
182 if (new->c_cflag & PARENB) {
183 if (!(new->c_cflag & PARODD))
184 cs |= AR933X_UART_CS_PARITY_EVEN;
185 else
186 cs |= AR933X_UART_CS_PARITY_ODD;
187 } else {
188 cs |= AR933X_UART_CS_PARITY_NONE;
189 }
190
191 /* Mark/space parity is not supported */
192 new->c_cflag &= ~CMSPAR;
193
194 baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
195 scale = (port->uartclk / (16 * baud)) - 1;
196
197 /*
198 * Ok, we're now changing the port state. Do it with
199 * interrupts disabled.
200 */
201 spin_lock_irqsave(&up->port.lock, flags);
202
203 /* Update the per-port timeout. */
204 uart_update_timeout(port, new->c_cflag, baud);
205
206 up->port.ignore_status_mask = 0;
207
208 /* ignore all characters if CREAD is not set */
209 if ((new->c_cflag & CREAD) == 0)
210 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
211
212 ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
213 scale << AR933X_UART_CLOCK_SCALE_S | 8192);
214
215 /* setup configuration register */
216 ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
217
218 /* enable host interrupt */
219 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
220 AR933X_UART_CS_HOST_INT_EN);
221
222 spin_unlock_irqrestore(&up->port.lock, flags);
223
224 if (tty_termios_baud_rate(new))
225 tty_termios_encode_baud_rate(new, baud, baud);
226 }
227
228 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
229 {
230 struct tty_struct *tty = up->port.state->port.tty;
231 int max_count = 256;
232
233 do {
234 unsigned int rdata;
235 unsigned char ch;
236
237 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
238 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
239 break;
240
241 /* remove the character from the FIFO */
242 ar933x_uart_write(up, AR933X_UART_DATA_REG,
243 AR933X_UART_DATA_RX_CSR);
244
245 up->port.icount.rx++;
246 ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
247
248 if (uart_handle_sysrq_char(&up->port, ch))
249 continue;
250
251 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
252 tty_insert_flip_char(tty, ch, TTY_NORMAL);
253 } while (max_count-- > 0);
254
255 tty_flip_buffer_push(tty);
256 }
257
258 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
259 {
260 struct circ_buf *xmit = &up->port.state->xmit;
261 int count;
262
263 if (uart_tx_stopped(&up->port))
264 return;
265
266 count = up->port.fifosize;
267 do {
268 unsigned int rdata;
269
270 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
271 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
272 break;
273
274 if (up->port.x_char) {
275 ar933x_uart_putc(up, up->port.x_char);
276 up->port.icount.tx++;
277 up->port.x_char = 0;
278 continue;
279 }
280
281 if (uart_circ_empty(xmit))
282 break;
283
284 ar933x_uart_putc(up, xmit->buf[xmit->tail]);
285
286 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
287 up->port.icount.tx++;
288 } while (--count > 0);
289
290 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
291 uart_write_wakeup(&up->port);
292
293 if (!uart_circ_empty(xmit))
294 ar933x_uart_start_tx_interrupt(up);
295 }
296
297 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
298 {
299 struct ar933x_uart_port *up = dev_id;
300 unsigned int status;
301
302 status = ar933x_uart_read(up, AR933X_UART_CS_REG);
303 if ((status & AR933X_UART_CS_HOST_INT) == 0)
304 return IRQ_NONE;
305
306 spin_lock(&up->port.lock);
307
308 status = ar933x_uart_read(up, AR933X_UART_INT_REG);
309 status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
310
311 if (status & AR933X_UART_INT_RX_VALID) {
312 ar933x_uart_write(up, AR933X_UART_INT_REG,
313 AR933X_UART_INT_RX_VALID);
314 ar933x_uart_rx_chars(up);
315 }
316
317 if (status & AR933X_UART_INT_TX_EMPTY) {
318 ar933x_uart_write(up, AR933X_UART_INT_REG,
319 AR933X_UART_INT_TX_EMPTY);
320 ar933x_uart_stop_tx_interrupt(up);
321 ar933x_uart_tx_chars(up);
322 }
323
324 spin_unlock(&up->port.lock);
325
326 return IRQ_HANDLED;
327 }
328
329 static int ar933x_uart_startup(struct uart_port *port)
330 {
331 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
332 unsigned long flags;
333 int ret;
334
335 ret = request_irq(up->port.irq, ar933x_uart_interrupt,
336 up->port.irqflags, dev_name(up->port.dev), up);
337 if (ret)
338 return ret;
339
340 spin_lock_irqsave(&up->port.lock, flags);
341
342 /* Enable HOST interrupts */
343 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
344 AR933X_UART_CS_HOST_INT_EN);
345
346 /* Enable RX interrupts */
347 up->ier = AR933X_UART_INT_RX_VALID;
348 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
349
350 spin_unlock_irqrestore(&up->port.lock, flags);
351
352 return 0;
353 }
354
355 static void ar933x_uart_shutdown(struct uart_port *port)
356 {
357 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
358
359 /* Disable all interrupts */
360 up->ier = 0;
361 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
362
363 /* Disable break condition */
364 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
365 AR933X_UART_CS_TX_BREAK);
366
367 free_irq(up->port.irq, up);
368 }
369
370 static const char *ar933x_uart_type(struct uart_port *port)
371 {
372 return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
373 }
374
375 static void ar933x_uart_release_port(struct uart_port *port)
376 {
377 /* Nothing to release ... */
378 }
379
380 static int ar933x_uart_request_port(struct uart_port *port)
381 {
382 /* UARTs always present */
383 return 0;
384 }
385
386 static void ar933x_uart_config_port(struct uart_port *port, int flags)
387 {
388 if (flags & UART_CONFIG_TYPE)
389 port->type = PORT_AR933X;
390 }
391
392 static int ar933x_uart_verify_port(struct uart_port *port,
393 struct serial_struct *ser)
394 {
395 if (ser->type != PORT_UNKNOWN &&
396 ser->type != PORT_AR933X)
397 return -EINVAL;
398
399 if (ser->irq < 0 || ser->irq >= NR_IRQS)
400 return -EINVAL;
401
402 if (ser->baud_base < 28800)
403 return -EINVAL;
404
405 return 0;
406 }
407
408 static struct uart_ops ar933x_uart_ops = {
409 .tx_empty = ar933x_uart_tx_empty,
410 .set_mctrl = ar933x_uart_set_mctrl,
411 .get_mctrl = ar933x_uart_get_mctrl,
412 .stop_tx = ar933x_uart_stop_tx,
413 .start_tx = ar933x_uart_start_tx,
414 .stop_rx = ar933x_uart_stop_rx,
415 .enable_ms = ar933x_uart_enable_ms,
416 .break_ctl = ar933x_uart_break_ctl,
417 .startup = ar933x_uart_startup,
418 .shutdown = ar933x_uart_shutdown,
419 .set_termios = ar933x_uart_set_termios,
420 .type = ar933x_uart_type,
421 .release_port = ar933x_uart_release_port,
422 .request_port = ar933x_uart_request_port,
423 .config_port = ar933x_uart_config_port,
424 .verify_port = ar933x_uart_verify_port,
425 };
426
427 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
428
429 static struct ar933x_uart_port *ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
430
431 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
432 {
433 unsigned int status;
434 unsigned int timeout = 60000;
435
436 /* Wait up to 60ms for the character(s) to be sent. */
437 do {
438 status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
439 if (--timeout == 0)
440 break;
441 udelay(1);
442 } while ((status & AR933X_UART_DATA_TX_CSR) == 0);
443 }
444
445 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
446 {
447 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
448
449 ar933x_uart_wait_xmitr(up);
450 ar933x_uart_putc(up, ch);
451 }
452
453 static void ar933x_uart_console_write(struct console *co, const char *s,
454 unsigned int count)
455 {
456 struct ar933x_uart_port *up = ar933x_console_ports[co->index];
457 unsigned long flags;
458 unsigned int int_en;
459 int locked = 1;
460
461 local_irq_save(flags);
462
463 if (up->port.sysrq)
464 locked = 0;
465 else if (oops_in_progress)
466 locked = spin_trylock(&up->port.lock);
467 else
468 spin_lock(&up->port.lock);
469
470 /*
471 * First save the IER then disable the interrupts
472 */
473 int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
474 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
475
476 uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
477
478 /*
479 * Finally, wait for transmitter to become empty
480 * and restore the IER
481 */
482 ar933x_uart_wait_xmitr(up);
483 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
484
485 ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
486
487 if (locked)
488 spin_unlock(&up->port.lock);
489
490 local_irq_restore(flags);
491 }
492
493 static int ar933x_uart_console_setup(struct console *co, char *options)
494 {
495 struct ar933x_uart_port *up;
496 int baud = 115200;
497 int bits = 8;
498 int parity = 'n';
499 int flow = 'n';
500
501 if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
502 return -EINVAL;
503
504 up = ar933x_console_ports[co->index];
505 if (!up)
506 return -ENODEV;
507
508 if (options)
509 uart_parse_options(options, &baud, &parity, &bits, &flow);
510
511 return uart_set_options(&up->port, co, baud, parity, bits, flow);
512 }
513
514 static struct console ar933x_uart_console = {
515 .name = "ttyATH",
516 .write = ar933x_uart_console_write,
517 .device = uart_console_device,
518 .setup = ar933x_uart_console_setup,
519 .flags = CON_PRINTBUFFER,
520 .index = -1,
521 .data = &ar933x_uart_driver,
522 };
523
524 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
525 {
526 ar933x_console_ports[up->port.line] = up;
527 }
528
529 #define AR933X_SERIAL_CONSOLE &ar933x_uart_console
530
531 #else
532
533 static inline void ar933x_uart_add_console_port(struct ar933x_uart_port *up) {}
534
535 #define AR933X_SERIAL_CONSOLE NULL
536
537 #endif /* CONFIG_SERIAL_AR933X_CONSOLE */
538
539 static struct uart_driver ar933x_uart_driver = {
540 .owner = THIS_MODULE,
541 .driver_name = DRIVER_NAME,
542 .dev_name = "ttyATH",
543 .nr = CONFIG_SERIAL_AR933X_NR_UARTS,
544 .cons = AR933X_SERIAL_CONSOLE,
545 };
546
547 static int __devinit ar933x_uart_probe(struct platform_device *pdev)
548 {
549 struct ar933x_uart_platform_data *pdata;
550 struct ar933x_uart_port *up;
551 struct uart_port *port;
552 struct resource *mem_res;
553 struct resource *irq_res;
554 int id;
555 int ret;
556
557 pdata = pdev->dev.platform_data;
558 if (!pdata)
559 return -EINVAL;
560
561 id = pdev->id;
562 if (id == -1)
563 id = 0;
564
565 if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
566 return -EINVAL;
567
568 mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
569 if (!mem_res) {
570 dev_err(&pdev->dev, "no MEM resource\n");
571 return -EINVAL;
572 }
573
574 irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
575 if (!irq_res) {
576 dev_err(&pdev->dev, "no IRQ resource\n");
577 return -EINVAL;
578 }
579
580 up = kzalloc(sizeof(struct ar933x_uart_port), GFP_KERNEL);
581 if (!up)
582 return -ENOMEM;
583
584 port = &up->port;
585 port->mapbase = mem_res->start;
586
587 port->membase = ioremap(mem_res->start, AR933X_UART_REGS_SIZE);
588 if (!port->membase) {
589 ret = -ENOMEM;
590 goto err_free_up;
591 }
592
593 port->line = id;
594 port->irq = irq_res->start;
595 port->dev = &pdev->dev;
596 port->type = PORT_AR933X;
597 port->iotype = UPIO_MEM32;
598 port->uartclk = pdata->uartclk;
599
600 port->regshift = 2;
601 port->fifosize = AR933X_UART_FIFO_SIZE;
602 port->ops = &ar933x_uart_ops;
603
604 ar933x_uart_add_console_port(up);
605
606 ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
607 if (ret)
608 goto err_unmap;
609
610 platform_set_drvdata(pdev, up);
611 return 0;
612
613 err_unmap:
614 iounmap(up->port.membase);
615 err_free_up:
616 kfree(up);
617 return ret;
618 }
619
620 static int __devexit ar933x_uart_remove(struct platform_device *pdev)
621 {
622 struct ar933x_uart_port *up;
623
624 up = platform_get_drvdata(pdev);
625 platform_set_drvdata(pdev, NULL);
626
627 if (up) {
628 uart_remove_one_port(&ar933x_uart_driver, &up->port);
629 iounmap(up->port.membase);
630 kfree(up);
631 }
632
633 return 0;
634 }
635
636 static struct platform_driver ar933x_uart_platform_driver = {
637 .probe = ar933x_uart_probe,
638 .remove = __devexit_p(ar933x_uart_remove),
639 .driver = {
640 .name = DRIVER_NAME,
641 .owner = THIS_MODULE,
642 },
643 };
644
645 static int __init ar933x_uart_init(void)
646 {
647 int ret;
648
649 ar933x_uart_driver.nr = CONFIG_SERIAL_AR933X_NR_UARTS;
650 ret = uart_register_driver(&ar933x_uart_driver);
651 if (ret)
652 goto err_out;
653
654 ret = platform_driver_register(&ar933x_uart_platform_driver);
655 if (ret)
656 goto err_unregister_uart_driver;
657
658 return 0;
659
660 err_unregister_uart_driver:
661 uart_unregister_driver(&ar933x_uart_driver);
662 err_out:
663 return ret;
664 }
665
666 static void __exit ar933x_uart_exit(void)
667 {
668 platform_driver_unregister(&ar933x_uart_platform_driver);
669 uart_unregister_driver(&ar933x_uart_driver);
670 }
671
672 module_init(ar933x_uart_init);
673 module_exit(ar933x_uart_exit);
674
675 MODULE_DESCRIPTION("Atheros AR933X UART driver");
676 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
677 MODULE_LICENSE("GPL v2");
678 MODULE_ALIAS("platform:" DRIVER_NAME);
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