?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
sched: Fix nohz balance kick
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / serial / altera_uart.c
blobf8d8a00554da2801177892d45878e387197e91e3
1 /*
2 * altera_uart.c -- Altera UART driver
3 *
4 * Based on mcf.c -- Freescale ColdFire UART driver
5 *
6 * (C) Copyright 2003-2007, Greg Ungerer <gerg@snapgear.com>
7 * (C) Copyright 2008, Thomas Chou <thomas@wytron.com.tw>
8 * (C) Copyright 2010, Tobias Klauser <tklauser@distanz.ch>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/module.h>
20 #include <linux/console.h>
21 #include <linux/tty.h>
22 #include <linux/tty_flip.h>
23 #include <linux/serial.h>
24 #include <linux/serial_core.h>
25 #include <linux/platform_device.h>
26 #include <linux/io.h>
27 #include <linux/altera_uart.h>
28
29 #define DRV_NAME "altera_uart"
30
31 /*
32 * Altera UART register definitions according to the Nios UART datasheet:
33 * http://www.altera.com/literature/ds/ds_nios_uart.pdf
34 */
35
36 #define ALTERA_UART_SIZE 32
37
38 #define ALTERA_UART_RXDATA_REG 0
39 #define ALTERA_UART_TXDATA_REG 4
40 #define ALTERA_UART_STATUS_REG 8
41 #define ALTERA_UART_CONTROL_REG 12
42 #define ALTERA_UART_DIVISOR_REG 16
43 #define ALTERA_UART_EOP_REG 20
44
45 #define ALTERA_UART_STATUS_PE_MSK 0x0001 /* parity error */
46 #define ALTERA_UART_STATUS_FE_MSK 0x0002 /* framing error */
47 #define ALTERA_UART_STATUS_BRK_MSK 0x0004 /* break */
48 #define ALTERA_UART_STATUS_ROE_MSK 0x0008 /* RX overrun error */
49 #define ALTERA_UART_STATUS_TOE_MSK 0x0010 /* TX overrun error */
50 #define ALTERA_UART_STATUS_TMT_MSK 0x0020 /* TX shift register state */
51 #define ALTERA_UART_STATUS_TRDY_MSK 0x0040 /* TX ready */
52 #define ALTERA_UART_STATUS_RRDY_MSK 0x0080 /* RX ready */
53 #define ALTERA_UART_STATUS_E_MSK 0x0100 /* exception condition */
54 #define ALTERA_UART_STATUS_DCTS_MSK 0x0400 /* CTS logic-level change */
55 #define ALTERA_UART_STATUS_CTS_MSK 0x0800 /* CTS logic state */
56 #define ALTERA_UART_STATUS_EOP_MSK 0x1000 /* EOP written/read */
57
58 /* Enable interrupt on... */
59 #define ALTERA_UART_CONTROL_PE_MSK 0x0001 /* ...parity error */
60 #define ALTERA_UART_CONTROL_FE_MSK 0x0002 /* ...framing error */
61 #define ALTERA_UART_CONTROL_BRK_MSK 0x0004 /* ...break */
62 #define ALTERA_UART_CONTROL_ROE_MSK 0x0008 /* ...RX overrun */
63 #define ALTERA_UART_CONTROL_TOE_MSK 0x0010 /* ...TX overrun */
64 #define ALTERA_UART_CONTROL_TMT_MSK 0x0020 /* ...TX shift register empty */
65 #define ALTERA_UART_CONTROL_TRDY_MSK 0x0040 /* ...TX ready */
66 #define ALTERA_UART_CONTROL_RRDY_MSK 0x0080 /* ...RX ready */
67 #define ALTERA_UART_CONTROL_E_MSK 0x0100 /* ...exception*/
68
69 #define ALTERA_UART_CONTROL_TRBK_MSK 0x0200 /* TX break */
70 #define ALTERA_UART_CONTROL_DCTS_MSK 0x0400 /* Interrupt on CTS change */
71 #define ALTERA_UART_CONTROL_RTS_MSK 0x0800 /* RTS signal */
72 #define ALTERA_UART_CONTROL_EOP_MSK 0x1000 /* Interrupt on EOP */
73
74 /*
75 * Local per-uart structure.
76 */
77 struct altera_uart {
78 struct uart_port port;
79 unsigned int sigs; /* Local copy of line sigs */
80 unsigned short imr; /* Local IMR mirror */
81 };
82
83 static unsigned int altera_uart_tx_empty(struct uart_port *port)
84 {
85 return (readl(port->membase + ALTERA_UART_STATUS_REG) &
86 ALTERA_UART_STATUS_TMT_MSK) ? TIOCSER_TEMT : 0;
87 }
88
89 static unsigned int altera_uart_get_mctrl(struct uart_port *port)
90 {
91 struct altera_uart *pp = container_of(port, struct altera_uart, port);
92 unsigned int sigs;
93
94 sigs =
95 (readl(port->membase + ALTERA_UART_STATUS_REG) &
96 ALTERA_UART_STATUS_CTS_MSK) ? TIOCM_CTS : 0;
97 sigs |= (pp->sigs & TIOCM_RTS);
98
99 return sigs;
100 }
101
102 static void altera_uart_set_mctrl(struct uart_port *port, unsigned int sigs)
103 {
104 struct altera_uart *pp = container_of(port, struct altera_uart, port);
105
106 pp->sigs = sigs;
107 if (sigs & TIOCM_RTS)
108 pp->imr |= ALTERA_UART_CONTROL_RTS_MSK;
109 else
110 pp->imr &= ~ALTERA_UART_CONTROL_RTS_MSK;
111 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
112 }
113
114 static void altera_uart_start_tx(struct uart_port *port)
115 {
116 struct altera_uart *pp = container_of(port, struct altera_uart, port);
117
118 pp->imr |= ALTERA_UART_CONTROL_TRDY_MSK;
119 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
120 }
121
122 static void altera_uart_stop_tx(struct uart_port *port)
123 {
124 struct altera_uart *pp = container_of(port, struct altera_uart, port);
125
126 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
127 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
128 }
129
130 static void altera_uart_stop_rx(struct uart_port *port)
131 {
132 struct altera_uart *pp = container_of(port, struct altera_uart, port);
133
134 pp->imr &= ~ALTERA_UART_CONTROL_RRDY_MSK;
135 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
136 }
137
138 static void altera_uart_break_ctl(struct uart_port *port, int break_state)
139 {
140 struct altera_uart *pp = container_of(port, struct altera_uart, port);
141 unsigned long flags;
142
143 spin_lock_irqsave(&port->lock, flags);
144 if (break_state == -1)
145 pp->imr |= ALTERA_UART_CONTROL_TRBK_MSK;
146 else
147 pp->imr &= ~ALTERA_UART_CONTROL_TRBK_MSK;
148 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
149 spin_unlock_irqrestore(&port->lock, flags);
150 }
151
152 static void altera_uart_enable_ms(struct uart_port *port)
153 {
154 }
155
156 static void altera_uart_set_termios(struct uart_port *port,
157 struct ktermios *termios,
158 struct ktermios *old)
159 {
160 unsigned long flags;
161 unsigned int baud, baudclk;
162
163 baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
164 baudclk = port->uartclk / baud;
165
166 if (old)
167 tty_termios_copy_hw(termios, old);
168 tty_termios_encode_baud_rate(termios, baud, baud);
169
170 spin_lock_irqsave(&port->lock, flags);
171 writel(baudclk, port->membase + ALTERA_UART_DIVISOR_REG);
172 spin_unlock_irqrestore(&port->lock, flags);
173 }
174
175 static void altera_uart_rx_chars(struct altera_uart *pp)
176 {
177 struct uart_port *port = &pp->port;
178 unsigned char ch, flag;
179 unsigned short status;
180
181 while ((status = readl(port->membase + ALTERA_UART_STATUS_REG)) &
182 ALTERA_UART_STATUS_RRDY_MSK) {
183 ch = readl(port->membase + ALTERA_UART_RXDATA_REG);
184 flag = TTY_NORMAL;
185 port->icount.rx++;
186
187 if (status & ALTERA_UART_STATUS_E_MSK) {
188 writel(status, port->membase + ALTERA_UART_STATUS_REG);
189
190 if (status & ALTERA_UART_STATUS_BRK_MSK) {
191 port->icount.brk++;
192 if (uart_handle_break(port))
193 continue;
194 } else if (status & ALTERA_UART_STATUS_PE_MSK) {
195 port->icount.parity++;
196 } else if (status & ALTERA_UART_STATUS_ROE_MSK) {
197 port->icount.overrun++;
198 } else if (status & ALTERA_UART_STATUS_FE_MSK) {
199 port->icount.frame++;
200 }
201
202 status &= port->read_status_mask;
203
204 if (status & ALTERA_UART_STATUS_BRK_MSK)
205 flag = TTY_BREAK;
206 else if (status & ALTERA_UART_STATUS_PE_MSK)
207 flag = TTY_PARITY;
208 else if (status & ALTERA_UART_STATUS_FE_MSK)
209 flag = TTY_FRAME;
210 }
211
212 if (uart_handle_sysrq_char(port, ch))
213 continue;
214 uart_insert_char(port, status, ALTERA_UART_STATUS_ROE_MSK, ch,
215 flag);
216 }
217
218 tty_flip_buffer_push(port->state->port.tty);
219 }
220
221 static void altera_uart_tx_chars(struct altera_uart *pp)
222 {
223 struct uart_port *port = &pp->port;
224 struct circ_buf *xmit = &port->state->xmit;
225
226 if (port->x_char) {
227 /* Send special char - probably flow control */
228 writel(port->x_char, port->membase + ALTERA_UART_TXDATA_REG);
229 port->x_char = 0;
230 port->icount.tx++;
231 return;
232 }
233
234 while (readl(port->membase + ALTERA_UART_STATUS_REG) &
235 ALTERA_UART_STATUS_TRDY_MSK) {
236 if (xmit->head == xmit->tail)
237 break;
238 writel(xmit->buf[xmit->tail],
239 port->membase + ALTERA_UART_TXDATA_REG);
240 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
241 port->icount.tx++;
242 }
243
244 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
245 uart_write_wakeup(port);
246
247 if (xmit->head == xmit->tail) {
248 pp->imr &= ~ALTERA_UART_CONTROL_TRDY_MSK;
249 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
250 }
251 }
252
253 static irqreturn_t altera_uart_interrupt(int irq, void *data)
254 {
255 struct uart_port *port = data;
256 struct altera_uart *pp = container_of(port, struct altera_uart, port);
257 unsigned int isr;
258
259 isr = readl(port->membase + ALTERA_UART_STATUS_REG) & pp->imr;
260
261 spin_lock(&port->lock);
262 if (isr & ALTERA_UART_STATUS_RRDY_MSK)
263 altera_uart_rx_chars(pp);
264 if (isr & ALTERA_UART_STATUS_TRDY_MSK)
265 altera_uart_tx_chars(pp);
266 spin_unlock(&port->lock);
267
268 return IRQ_RETVAL(isr);
269 }
270
271 static void altera_uart_config_port(struct uart_port *port, int flags)
272 {
273 port->type = PORT_ALTERA_UART;
274
275 /* Clear mask, so no surprise interrupts. */
276 writel(0, port->membase + ALTERA_UART_CONTROL_REG);
277 /* Clear status register */
278 writel(0, port->membase + ALTERA_UART_STATUS_REG);
279 }
280
281 static int altera_uart_startup(struct uart_port *port)
282 {
283 struct altera_uart *pp = container_of(port, struct altera_uart, port);
284 unsigned long flags;
285 int ret;
286
287 ret = request_irq(port->irq, altera_uart_interrupt, IRQF_DISABLED,
288 DRV_NAME, port);
289 if (ret) {
290 pr_err(DRV_NAME ": unable to attach Altera UART %d "
291 "interrupt vector=%d\n", port->line, port->irq);
292 return ret;
293 }
294
295 spin_lock_irqsave(&port->lock, flags);
296
297 /* Enable RX interrupts now */
298 pp->imr = ALTERA_UART_CONTROL_RRDY_MSK;
299 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
300
301 spin_unlock_irqrestore(&port->lock, flags);
302
303 return 0;
304 }
305
306 static void altera_uart_shutdown(struct uart_port *port)
307 {
308 struct altera_uart *pp = container_of(port, struct altera_uart, port);
309 unsigned long flags;
310
311 spin_lock_irqsave(&port->lock, flags);
312
313 /* Disable all interrupts now */
314 pp->imr = 0;
315 writel(pp->imr, port->membase + ALTERA_UART_CONTROL_REG);
316
317 spin_unlock_irqrestore(&port->lock, flags);
318
319 free_irq(port->irq, port);
320 }
321
322 static const char *altera_uart_type(struct uart_port *port)
323 {
324 return (port->type == PORT_ALTERA_UART) ? "Altera UART" : NULL;
325 }
326
327 static int altera_uart_request_port(struct uart_port *port)
328 {
329 /* UARTs always present */
330 return 0;
331 }
332
333 static void altera_uart_release_port(struct uart_port *port)
334 {
335 /* Nothing to release... */
336 }
337
338 static int altera_uart_verify_port(struct uart_port *port,
339 struct serial_struct *ser)
340 {
341 if ((ser->type != PORT_UNKNOWN) && (ser->type != PORT_ALTERA_UART))
342 return -EINVAL;
343 return 0;
344 }
345
346 /*
347 * Define the basic serial functions we support.
348 */
349 static struct uart_ops altera_uart_ops = {
350 .tx_empty = altera_uart_tx_empty,
351 .get_mctrl = altera_uart_get_mctrl,
352 .set_mctrl = altera_uart_set_mctrl,
353 .start_tx = altera_uart_start_tx,
354 .stop_tx = altera_uart_stop_tx,
355 .stop_rx = altera_uart_stop_rx,
356 .enable_ms = altera_uart_enable_ms,
357 .break_ctl = altera_uart_break_ctl,
358 .startup = altera_uart_startup,
359 .shutdown = altera_uart_shutdown,
360 .set_termios = altera_uart_set_termios,
361 .type = altera_uart_type,
362 .request_port = altera_uart_request_port,
363 .release_port = altera_uart_release_port,
364 .config_port = altera_uart_config_port,
365 .verify_port = altera_uart_verify_port,
366 };
367
368 static struct altera_uart altera_uart_ports[CONFIG_SERIAL_ALTERA_UART_MAXPORTS];
369
370 #if defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
371
372 int __init early_altera_uart_setup(struct altera_uart_platform_uart *platp)
373 {
374 struct uart_port *port;
375 int i;
376
377 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS && platp[i].mapbase; i++) {
378 port = &altera_uart_ports[i].port;
379
380 port->line = i;
381 port->type = PORT_ALTERA_UART;
382 port->mapbase = platp[i].mapbase;
383 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
384 port->iotype = SERIAL_IO_MEM;
385 port->irq = platp[i].irq;
386 port->uartclk = platp[i].uartclk;
387 port->flags = ASYNC_BOOT_AUTOCONF;
388 port->ops = &altera_uart_ops;
389 }
390
391 return 0;
392 }
393
394 static void altera_uart_console_putc(struct uart_port *port, const char c)
395 {
396 while (!(readl(port->membase + ALTERA_UART_STATUS_REG) &
397 ALTERA_UART_STATUS_TRDY_MSK))
398 cpu_relax();
399
400 writel(c, port->membase + ALTERA_UART_TXDATA_REG);
401 }
402
403 static void altera_uart_console_write(struct console *co, const char *s,
404 unsigned int count)
405 {
406 struct uart_port *port = &(altera_uart_ports + co->index)->port;
407
408 for (; count; count--, s++) {
409 altera_uart_console_putc(port, *s);
410 if (*s == '\n')
411 altera_uart_console_putc(port, '\r');
412 }
413 }
414
415 static int __init altera_uart_console_setup(struct console *co, char *options)
416 {
417 struct uart_port *port;
418 int baud = CONFIG_SERIAL_ALTERA_UART_BAUDRATE;
419 int bits = 8;
420 int parity = 'n';
421 int flow = 'n';
422
423 if (co->index < 0 || co->index >= CONFIG_SERIAL_ALTERA_UART_MAXPORTS)
424 return -EINVAL;
425 port = &altera_uart_ports[co->index].port;
426 if (port->membase == 0)
427 return -ENODEV;
428
429 if (options)
430 uart_parse_options(options, &baud, &parity, &bits, &flow);
431
432 return uart_set_options(port, co, baud, parity, bits, flow);
433 }
434
435 static struct uart_driver altera_uart_driver;
436
437 static struct console altera_uart_console = {
438 .name = "ttyS",
439 .write = altera_uart_console_write,
440 .device = uart_console_device,
441 .setup = altera_uart_console_setup,
442 .flags = CON_PRINTBUFFER,
443 .index = -1,
444 .data = &altera_uart_driver,
445 };
446
447 static int __init altera_uart_console_init(void)
448 {
449 register_console(&altera_uart_console);
450 return 0;
451 }
452
453 console_initcall(altera_uart_console_init);
454
455 #define ALTERA_UART_CONSOLE (&altera_uart_console)
456
457 #else
458
459 #define ALTERA_UART_CONSOLE NULL
460
461 #endif /* CONFIG_ALTERA_UART_CONSOLE */
462
463 /*
464 * Define the altera_uart UART driver structure.
465 */
466 static struct uart_driver altera_uart_driver = {
467 .owner = THIS_MODULE,
468 .driver_name = DRV_NAME,
469 .dev_name = "ttyS",
470 .major = TTY_MAJOR,
471 .minor = 64,
472 .nr = CONFIG_SERIAL_ALTERA_UART_MAXPORTS,
473 .cons = ALTERA_UART_CONSOLE,
474 };
475
476 static int __devinit altera_uart_probe(struct platform_device *pdev)
477 {
478 struct altera_uart_platform_uart *platp = pdev->dev.platform_data;
479 struct uart_port *port;
480 int i;
481
482 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS && platp[i].mapbase; i++) {
483 port = &altera_uart_ports[i].port;
484
485 port->line = i;
486 port->type = PORT_ALTERA_UART;
487 port->mapbase = platp[i].mapbase;
488 port->membase = ioremap(port->mapbase, ALTERA_UART_SIZE);
489 port->iotype = SERIAL_IO_MEM;
490 port->irq = platp[i].irq;
491 port->uartclk = platp[i].uartclk;
492 port->ops = &altera_uart_ops;
493 port->flags = ASYNC_BOOT_AUTOCONF;
494
495 uart_add_one_port(&altera_uart_driver, port);
496 }
497
498 return 0;
499 }
500
501 static int __devexit altera_uart_remove(struct platform_device *pdev)
502 {
503 struct uart_port *port;
504 int i;
505
506 for (i = 0; i < CONFIG_SERIAL_ALTERA_UART_MAXPORTS; i++) {
507 port = &altera_uart_ports[i].port;
508 if (port)
509 uart_remove_one_port(&altera_uart_driver, port);
510 }
511
512 return 0;
513 }
514
515 static struct platform_driver altera_uart_platform_driver = {
516 .probe = altera_uart_probe,
517 .remove = __devexit_p(altera_uart_remove),
518 .driver = {
519 .name = DRV_NAME,
520 .owner = THIS_MODULE,
521 .pm = NULL,
522 },
523 };
524
525 static int __init altera_uart_init(void)
526 {
527 int rc;
528
529 rc = uart_register_driver(&altera_uart_driver);
530 if (rc)
531 return rc;
532 rc = platform_driver_register(&altera_uart_platform_driver);
533 if (rc) {
534 uart_unregister_driver(&altera_uart_driver);
535 return rc;
536 }
537 return 0;
538 }
539
540 static void __exit altera_uart_exit(void)
541 {
542 platform_driver_unregister(&altera_uart_platform_driver);
543 uart_unregister_driver(&altera_uart_driver);
544 }
545
546 module_init(altera_uart_init);
547 module_exit(altera_uart_exit);
548
549 MODULE_DESCRIPTION("Altera UART driver");
550 MODULE_AUTHOR("Thomas Chou <thomas@wytron.com.tw>");
551 MODULE_LICENSE("GPL");
552 MODULE_ALIAS("platform:" DRV_NAME);
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree