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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[linux-btrfs-devel.git] / drivers / tty / serial / timbuart.c
bloba4b63bfeaa2f4e1a03d80ac0db64b6a883726325
1 /*
2 * timbuart.c timberdale FPGA UART driver
3 * Copyright (c) 2009 Intel Corporation
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 /* Supports:
20 * Timberdale FPGA UART
21 */
22
23 #include <linux/pci.h>
24 #include <linux/interrupt.h>
25 #include <linux/serial_core.h>
26 #include <linux/tty.h>
27 #include <linux/tty_flip.h>
28 #include <linux/kernel.h>
29 #include <linux/platform_device.h>
30 #include <linux/ioport.h>
31 #include <linux/slab.h>
32
33 #include "timbuart.h"
34
35 struct timbuart_port {
36 struct uart_port port;
37 struct tasklet_struct tasklet;
38 int usedma;
39 u32 last_ier;
40 struct platform_device *dev;
41 };
42
43 static int baudrates[] = {9600, 19200, 38400, 57600, 115200, 230400, 460800,
44 921600, 1843200, 3250000};
45
46 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier);
47
48 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid);
49
50 static void timbuart_stop_rx(struct uart_port *port)
51 {
52 /* spin lock held by upper layer, disable all RX interrupts */
53 u32 ier = ioread32(port->membase + TIMBUART_IER) & ~RXFLAGS;
54 iowrite32(ier, port->membase + TIMBUART_IER);
55 }
56
57 static void timbuart_stop_tx(struct uart_port *port)
58 {
59 /* spinlock held by upper layer, disable TX interrupt */
60 u32 ier = ioread32(port->membase + TIMBUART_IER) & ~TXBAE;
61 iowrite32(ier, port->membase + TIMBUART_IER);
62 }
63
64 static void timbuart_start_tx(struct uart_port *port)
65 {
66 struct timbuart_port *uart =
67 container_of(port, struct timbuart_port, port);
68
69 /* do not transfer anything here -> fire off the tasklet */
70 tasklet_schedule(&uart->tasklet);
71 }
72
73 static unsigned int timbuart_tx_empty(struct uart_port *port)
74 {
75 u32 isr = ioread32(port->membase + TIMBUART_ISR);
76
77 return (isr & TXBE) ? TIOCSER_TEMT : 0;
78 }
79
80 static void timbuart_flush_buffer(struct uart_port *port)
81 {
82 if (!timbuart_tx_empty(port)) {
83 u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
84 TIMBUART_CTRL_FLSHTX;
85
86 iowrite8(ctl, port->membase + TIMBUART_CTRL);
87 iowrite32(TXBF, port->membase + TIMBUART_ISR);
88 }
89 }
90
91 static void timbuart_rx_chars(struct uart_port *port)
92 {
93 struct tty_struct *tty = port->state->port.tty;
94
95 while (ioread32(port->membase + TIMBUART_ISR) & RXDP) {
96 u8 ch = ioread8(port->membase + TIMBUART_RXFIFO);
97 port->icount.rx++;
98 tty_insert_flip_char(tty, ch, TTY_NORMAL);
99 }
100
101 spin_unlock(&port->lock);
102 tty_flip_buffer_push(port->state->port.tty);
103 spin_lock(&port->lock);
104
105 dev_dbg(port->dev, "%s - total read %d bytes\n",
106 __func__, port->icount.rx);
107 }
108
109 static void timbuart_tx_chars(struct uart_port *port)
110 {
111 struct circ_buf *xmit = &port->state->xmit;
112
113 while (!(ioread32(port->membase + TIMBUART_ISR) & TXBF) &&
114 !uart_circ_empty(xmit)) {
115 iowrite8(xmit->buf[xmit->tail],
116 port->membase + TIMBUART_TXFIFO);
117 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
118 port->icount.tx++;
119 }
120
121 dev_dbg(port->dev,
122 "%s - total written %d bytes, CTL: %x, RTS: %x, baud: %x\n",
123 __func__,
124 port->icount.tx,
125 ioread8(port->membase + TIMBUART_CTRL),
126 port->mctrl & TIOCM_RTS,
127 ioread8(port->membase + TIMBUART_BAUDRATE));
128 }
129
130 static void timbuart_handle_tx_port(struct uart_port *port, u32 isr, u32 *ier)
131 {
132 struct timbuart_port *uart =
133 container_of(port, struct timbuart_port, port);
134 struct circ_buf *xmit = &port->state->xmit;
135
136 if (uart_circ_empty(xmit) || uart_tx_stopped(port))
137 return;
138
139 if (port->x_char)
140 return;
141
142 if (isr & TXFLAGS) {
143 timbuart_tx_chars(port);
144 /* clear all TX interrupts */
145 iowrite32(TXFLAGS, port->membase + TIMBUART_ISR);
146
147 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
148 uart_write_wakeup(port);
149 } else
150 /* Re-enable any tx interrupt */
151 *ier |= uart->last_ier & TXFLAGS;
152
153 /* enable interrupts if there are chars in the transmit buffer,
154 * Or if we delivered some bytes and want the almost empty interrupt
155 * we wake up the upper layer later when we got the interrupt
156 * to give it some time to go out...
157 */
158 if (!uart_circ_empty(xmit))
159 *ier |= TXBAE;
160
161 dev_dbg(port->dev, "%s - leaving\n", __func__);
162 }
163
164 void timbuart_handle_rx_port(struct uart_port *port, u32 isr, u32 *ier)
165 {
166 if (isr & RXFLAGS) {
167 /* Some RX status is set */
168 if (isr & RXBF) {
169 u8 ctl = ioread8(port->membase + TIMBUART_CTRL) |
170 TIMBUART_CTRL_FLSHRX;
171 iowrite8(ctl, port->membase + TIMBUART_CTRL);
172 port->icount.overrun++;
173 } else if (isr & (RXDP))
174 timbuart_rx_chars(port);
175
176 /* ack all RX interrupts */
177 iowrite32(RXFLAGS, port->membase + TIMBUART_ISR);
178 }
179
180 /* always have the RX interrupts enabled */
181 *ier |= RXBAF | RXBF | RXTT;
182
183 dev_dbg(port->dev, "%s - leaving\n", __func__);
184 }
185
186 void timbuart_tasklet(unsigned long arg)
187 {
188 struct timbuart_port *uart = (struct timbuart_port *)arg;
189 u32 isr, ier = 0;
190
191 spin_lock(&uart->port.lock);
192
193 isr = ioread32(uart->port.membase + TIMBUART_ISR);
194 dev_dbg(uart->port.dev, "%s ISR: %x\n", __func__, isr);
195
196 if (!uart->usedma)
197 timbuart_handle_tx_port(&uart->port, isr, &ier);
198
199 timbuart_mctrl_check(&uart->port, isr, &ier);
200
201 if (!uart->usedma)
202 timbuart_handle_rx_port(&uart->port, isr, &ier);
203
204 iowrite32(ier, uart->port.membase + TIMBUART_IER);
205
206 spin_unlock(&uart->port.lock);
207 dev_dbg(uart->port.dev, "%s leaving\n", __func__);
208 }
209
210 static unsigned int timbuart_get_mctrl(struct uart_port *port)
211 {
212 u8 cts = ioread8(port->membase + TIMBUART_CTRL);
213 dev_dbg(port->dev, "%s - cts %x\n", __func__, cts);
214
215 if (cts & TIMBUART_CTRL_CTS)
216 return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
217 else
218 return TIOCM_DSR | TIOCM_CAR;
219 }
220
221 static void timbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
222 {
223 dev_dbg(port->dev, "%s - %x\n", __func__, mctrl);
224
225 if (mctrl & TIOCM_RTS)
226 iowrite8(TIMBUART_CTRL_RTS, port->membase + TIMBUART_CTRL);
227 else
228 iowrite8(0, port->membase + TIMBUART_CTRL);
229 }
230
231 static void timbuart_mctrl_check(struct uart_port *port, u32 isr, u32 *ier)
232 {
233 unsigned int cts;
234
235 if (isr & CTS_DELTA) {
236 /* ack */
237 iowrite32(CTS_DELTA, port->membase + TIMBUART_ISR);
238 cts = timbuart_get_mctrl(port);
239 uart_handle_cts_change(port, cts & TIOCM_CTS);
240 wake_up_interruptible(&port->state->port.delta_msr_wait);
241 }
242
243 *ier |= CTS_DELTA;
244 }
245
246 static void timbuart_enable_ms(struct uart_port *port)
247 {
248 /* N/A */
249 }
250
251 static void timbuart_break_ctl(struct uart_port *port, int ctl)
252 {
253 /* N/A */
254 }
255
256 static int timbuart_startup(struct uart_port *port)
257 {
258 struct timbuart_port *uart =
259 container_of(port, struct timbuart_port, port);
260
261 dev_dbg(port->dev, "%s\n", __func__);
262
263 iowrite8(TIMBUART_CTRL_FLSHRX, port->membase + TIMBUART_CTRL);
264 iowrite32(0x1ff, port->membase + TIMBUART_ISR);
265 /* Enable all but TX interrupts */
266 iowrite32(RXBAF | RXBF | RXTT | CTS_DELTA,
267 port->membase + TIMBUART_IER);
268
269 return request_irq(port->irq, timbuart_handleinterrupt, IRQF_SHARED,
270 "timb-uart", uart);
271 }
272
273 static void timbuart_shutdown(struct uart_port *port)
274 {
275 struct timbuart_port *uart =
276 container_of(port, struct timbuart_port, port);
277 dev_dbg(port->dev, "%s\n", __func__);
278 free_irq(port->irq, uart);
279 iowrite32(0, port->membase + TIMBUART_IER);
280 }
281
282 static int get_bindex(int baud)
283 {
284 int i;
285
286 for (i = 0; i < ARRAY_SIZE(baudrates); i++)
287 if (baud <= baudrates[i])
288 return i;
289
290 return -1;
291 }
292
293 static void timbuart_set_termios(struct uart_port *port,
294 struct ktermios *termios,
295 struct ktermios *old)
296 {
297 unsigned int baud;
298 short bindex;
299 unsigned long flags;
300
301 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
302 bindex = get_bindex(baud);
303 dev_dbg(port->dev, "%s - bindex %d\n", __func__, bindex);
304
305 if (bindex < 0)
306 bindex = 0;
307 baud = baudrates[bindex];
308
309 /* The serial layer calls into this once with old = NULL when setting
310 up initially */
311 if (old)
312 tty_termios_copy_hw(termios, old);
313 tty_termios_encode_baud_rate(termios, baud, baud);
314
315 spin_lock_irqsave(&port->lock, flags);
316 iowrite8((u8)bindex, port->membase + TIMBUART_BAUDRATE);
317 uart_update_timeout(port, termios->c_cflag, baud);
318 spin_unlock_irqrestore(&port->lock, flags);
319 }
320
321 static const char *timbuart_type(struct uart_port *port)
322 {
323 return port->type == PORT_UNKNOWN ? "timbuart" : NULL;
324 }
325
326 /* We do not request/release mappings of the registers here,
327 * currently it's done in the proble function.
328 */
329 static void timbuart_release_port(struct uart_port *port)
330 {
331 struct platform_device *pdev = to_platform_device(port->dev);
332 int size =
333 resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
334
335 if (port->flags & UPF_IOREMAP) {
336 iounmap(port->membase);
337 port->membase = NULL;
338 }
339
340 release_mem_region(port->mapbase, size);
341 }
342
343 static int timbuart_request_port(struct uart_port *port)
344 {
345 struct platform_device *pdev = to_platform_device(port->dev);
346 int size =
347 resource_size(platform_get_resource(pdev, IORESOURCE_MEM, 0));
348
349 if (!request_mem_region(port->mapbase, size, "timb-uart"))
350 return -EBUSY;
351
352 if (port->flags & UPF_IOREMAP) {
353 port->membase = ioremap(port->mapbase, size);
354 if (port->membase == NULL) {
355 release_mem_region(port->mapbase, size);
356 return -ENOMEM;
357 }
358 }
359
360 return 0;
361 }
362
363 static irqreturn_t timbuart_handleinterrupt(int irq, void *devid)
364 {
365 struct timbuart_port *uart = (struct timbuart_port *)devid;
366
367 if (ioread8(uart->port.membase + TIMBUART_IPR)) {
368 uart->last_ier = ioread32(uart->port.membase + TIMBUART_IER);
369
370 /* disable interrupts, the tasklet enables them again */
371 iowrite32(0, uart->port.membase + TIMBUART_IER);
372
373 /* fire off bottom half */
374 tasklet_schedule(&uart->tasklet);
375
376 return IRQ_HANDLED;
377 } else
378 return IRQ_NONE;
379 }
380
381 /*
382 * Configure/autoconfigure the port.
383 */
384 static void timbuart_config_port(struct uart_port *port, int flags)
385 {
386 if (flags & UART_CONFIG_TYPE) {
387 port->type = PORT_TIMBUART;
388 timbuart_request_port(port);
389 }
390 }
391
392 static int timbuart_verify_port(struct uart_port *port,
393 struct serial_struct *ser)
394 {
395 /* we don't want the core code to modify any port params */
396 return -EINVAL;
397 }
398
399 static struct uart_ops timbuart_ops = {
400 .tx_empty = timbuart_tx_empty,
401 .set_mctrl = timbuart_set_mctrl,
402 .get_mctrl = timbuart_get_mctrl,
403 .stop_tx = timbuart_stop_tx,
404 .start_tx = timbuart_start_tx,
405 .flush_buffer = timbuart_flush_buffer,
406 .stop_rx = timbuart_stop_rx,
407 .enable_ms = timbuart_enable_ms,
408 .break_ctl = timbuart_break_ctl,
409 .startup = timbuart_startup,
410 .shutdown = timbuart_shutdown,
411 .set_termios = timbuart_set_termios,
412 .type = timbuart_type,
413 .release_port = timbuart_release_port,
414 .request_port = timbuart_request_port,
415 .config_port = timbuart_config_port,
416 .verify_port = timbuart_verify_port
417 };
418
419 static struct uart_driver timbuart_driver = {
420 .owner = THIS_MODULE,
421 .driver_name = "timberdale_uart",
422 .dev_name = "ttyTU",
423 .major = TIMBUART_MAJOR,
424 .minor = TIMBUART_MINOR,
425 .nr = 1
426 };
427
428 static int __devinit timbuart_probe(struct platform_device *dev)
429 {
430 int err, irq;
431 struct timbuart_port *uart;
432 struct resource *iomem;
433
434 dev_dbg(&dev->dev, "%s\n", __func__);
435
436 uart = kzalloc(sizeof(*uart), GFP_KERNEL);
437 if (!uart) {
438 err = -EINVAL;
439 goto err_mem;
440 }
441
442 uart->usedma = 0;
443
444 uart->port.uartclk = 3250000 * 16;
445 uart->port.fifosize = TIMBUART_FIFO_SIZE;
446 uart->port.regshift = 2;
447 uart->port.iotype = UPIO_MEM;
448 uart->port.ops = &timbuart_ops;
449 uart->port.irq = 0;
450 uart->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP;
451 uart->port.line = 0;
452 uart->port.dev = &dev->dev;
453
454 iomem = platform_get_resource(dev, IORESOURCE_MEM, 0);
455 if (!iomem) {
456 err = -ENOMEM;
457 goto err_register;
458 }
459 uart->port.mapbase = iomem->start;
460 uart->port.membase = NULL;
461
462 irq = platform_get_irq(dev, 0);
463 if (irq < 0) {
464 err = -EINVAL;
465 goto err_register;
466 }
467 uart->port.irq = irq;
468
469 tasklet_init(&uart->tasklet, timbuart_tasklet, (unsigned long)uart);
470
471 err = uart_register_driver(&timbuart_driver);
472 if (err)
473 goto err_register;
474
475 err = uart_add_one_port(&timbuart_driver, &uart->port);
476 if (err)
477 goto err_add_port;
478
479 platform_set_drvdata(dev, uart);
480
481 return 0;
482
483 err_add_port:
484 uart_unregister_driver(&timbuart_driver);
485 err_register:
486 kfree(uart);
487 err_mem:
488 printk(KERN_ERR "timberdale: Failed to register Timberdale UART: %d\n",
489 err);
490
491 return err;
492 }
493
494 static int __devexit timbuart_remove(struct platform_device *dev)
495 {
496 struct timbuart_port *uart = platform_get_drvdata(dev);
497
498 tasklet_kill(&uart->tasklet);
499 uart_remove_one_port(&timbuart_driver, &uart->port);
500 uart_unregister_driver(&timbuart_driver);
501 kfree(uart);
502
503 return 0;
504 }
505
506 static struct platform_driver timbuart_platform_driver = {
507 .driver = {
508 .name = "timb-uart",
509 .owner = THIS_MODULE,
510 },
511 .probe = timbuart_probe,
512 .remove = __devexit_p(timbuart_remove),
513 };
514
515 /*--------------------------------------------------------------------------*/
516
517 static int __init timbuart_init(void)
518 {
519 return platform_driver_register(&timbuart_platform_driver);
520 }
521
522 static void __exit timbuart_exit(void)
523 {
524 platform_driver_unregister(&timbuart_platform_driver);
525 }
526
527 module_init(timbuart_init);
528 module_exit(timbuart_exit);
529
530 MODULE_DESCRIPTION("Timberdale UART driver");
531 MODULE_LICENSE("GPL v2");
532 MODULE_ALIAS("platform:timb-uart");
533
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