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Merge git://git.kernel.org/pub/scm/linux/kernel/git/agk/linux-2.6-dm
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / tty / serial / amba-pl011.c
blob57731e87008591675eb029598bee843d54c1eb47
1 /*
2 * linux/drivers/char/amba.c
3 *
4 * Driver for AMBA serial ports
5 *
6 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
7 *
8 * Copyright 1999 ARM Limited
9 * Copyright (C) 2000 Deep Blue Solutions Ltd.
10 * Copyright (C) 2010 ST-Ericsson SA
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, write to the Free Software
24 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 *
26 * This is a generic driver for ARM AMBA-type serial ports. They
27 * have a lot of 16550-like features, but are not register compatible.
28 * Note that although they do have CTS, DCD and DSR inputs, they do
29 * not have an RI input, nor do they have DTR or RTS outputs. If
30 * required, these have to be supplied via some other means (eg, GPIO)
31 * and hooked into this driver.
32 */
33
34 #if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
35 #define SUPPORT_SYSRQ
36 #endif
37
38 #include <linux/module.h>
39 #include <linux/ioport.h>
40 #include <linux/init.h>
41 #include <linux/console.h>
42 #include <linux/sysrq.h>
43 #include <linux/device.h>
44 #include <linux/tty.h>
45 #include <linux/tty_flip.h>
46 #include <linux/serial_core.h>
47 #include <linux/serial.h>
48 #include <linux/amba/bus.h>
49 #include <linux/amba/serial.h>
50 #include <linux/clk.h>
51 #include <linux/slab.h>
52 #include <linux/dmaengine.h>
53 #include <linux/dma-mapping.h>
54 #include <linux/scatterlist.h>
55
56 #include <asm/io.h>
57 #include <asm/sizes.h>
58
59 #define UART_NR 14
60
61 #define SERIAL_AMBA_MAJOR 204
62 #define SERIAL_AMBA_MINOR 64
63 #define SERIAL_AMBA_NR UART_NR
64
65 #define AMBA_ISR_PASS_LIMIT 256
66
67 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
68 #define UART_DUMMY_DR_RX (1 << 16)
69
70 /* There is by now at least one vendor with differing details, so handle it */
71 struct vendor_data {
72 unsigned int ifls;
73 unsigned int fifosize;
74 unsigned int lcrh_tx;
75 unsigned int lcrh_rx;
76 bool oversampling;
77 bool dma_threshold;
78 };
79
80 static struct vendor_data vendor_arm = {
81 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
82 .fifosize = 16,
83 .lcrh_tx = UART011_LCRH,
84 .lcrh_rx = UART011_LCRH,
85 .oversampling = false,
86 .dma_threshold = false,
87 };
88
89 static struct vendor_data vendor_st = {
90 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
91 .fifosize = 64,
92 .lcrh_tx = ST_UART011_LCRH_TX,
93 .lcrh_rx = ST_UART011_LCRH_RX,
94 .oversampling = true,
95 .dma_threshold = true,
96 };
97
98 /* Deals with DMA transactions */
99
100 struct pl011_sgbuf {
101 struct scatterlist sg;
102 char *buf;
103 };
104
105 struct pl011_dmarx_data {
106 struct dma_chan *chan;
107 struct completion complete;
108 bool use_buf_b;
109 struct pl011_sgbuf sgbuf_a;
110 struct pl011_sgbuf sgbuf_b;
111 dma_cookie_t cookie;
112 bool running;
113 };
114
115 struct pl011_dmatx_data {
116 struct dma_chan *chan;
117 struct scatterlist sg;
118 char *buf;
119 bool queued;
120 };
121
122 /*
123 * We wrap our port structure around the generic uart_port.
124 */
125 struct uart_amba_port {
126 struct uart_port port;
127 struct clk *clk;
128 const struct vendor_data *vendor;
129 unsigned int dmacr; /* dma control reg */
130 unsigned int im; /* interrupt mask */
131 unsigned int old_status;
132 unsigned int fifosize; /* vendor-specific */
133 unsigned int lcrh_tx; /* vendor-specific */
134 unsigned int lcrh_rx; /* vendor-specific */
135 bool autorts;
136 char type[12];
137 #ifdef CONFIG_DMA_ENGINE
138 /* DMA stuff */
139 bool using_tx_dma;
140 bool using_rx_dma;
141 struct pl011_dmarx_data dmarx;
142 struct pl011_dmatx_data dmatx;
143 #endif
144 };
145
146 /*
147 * Reads up to 256 characters from the FIFO or until it's empty and
148 * inserts them into the TTY layer. Returns the number of characters
149 * read from the FIFO.
150 */
151 static int pl011_fifo_to_tty(struct uart_amba_port *uap)
152 {
153 u16 status, ch;
154 unsigned int flag, max_count = 256;
155 int fifotaken = 0;
156
157 while (max_count--) {
158 status = readw(uap->port.membase + UART01x_FR);
159 if (status & UART01x_FR_RXFE)
160 break;
161
162 /* Take chars from the FIFO and update status */
163 ch = readw(uap->port.membase + UART01x_DR) |
164 UART_DUMMY_DR_RX;
165 flag = TTY_NORMAL;
166 uap->port.icount.rx++;
167 fifotaken++;
168
169 if (unlikely(ch & UART_DR_ERROR)) {
170 if (ch & UART011_DR_BE) {
171 ch &= ~(UART011_DR_FE | UART011_DR_PE);
172 uap->port.icount.brk++;
173 if (uart_handle_break(&uap->port))
174 continue;
175 } else if (ch & UART011_DR_PE)
176 uap->port.icount.parity++;
177 else if (ch & UART011_DR_FE)
178 uap->port.icount.frame++;
179 if (ch & UART011_DR_OE)
180 uap->port.icount.overrun++;
181
182 ch &= uap->port.read_status_mask;
183
184 if (ch & UART011_DR_BE)
185 flag = TTY_BREAK;
186 else if (ch & UART011_DR_PE)
187 flag = TTY_PARITY;
188 else if (ch & UART011_DR_FE)
189 flag = TTY_FRAME;
190 }
191
192 if (uart_handle_sysrq_char(&uap->port, ch & 255))
193 continue;
194
195 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
196 }
197
198 return fifotaken;
199 }
200
201
202 /*
203 * All the DMA operation mode stuff goes inside this ifdef.
204 * This assumes that you have a generic DMA device interface,
205 * no custom DMA interfaces are supported.
206 */
207 #ifdef CONFIG_DMA_ENGINE
208
209 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE
210
211 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
212 enum dma_data_direction dir)
213 {
214 sg->buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
215 if (!sg->buf)
216 return -ENOMEM;
217
218 sg_init_one(&sg->sg, sg->buf, PL011_DMA_BUFFER_SIZE);
219
220 if (dma_map_sg(chan->device->dev, &sg->sg, 1, dir) != 1) {
221 kfree(sg->buf);
222 return -EINVAL;
223 }
224 return 0;
225 }
226
227 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
228 enum dma_data_direction dir)
229 {
230 if (sg->buf) {
231 dma_unmap_sg(chan->device->dev, &sg->sg, 1, dir);
232 kfree(sg->buf);
233 }
234 }
235
236 static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
237 {
238 /* DMA is the sole user of the platform data right now */
239 struct amba_pl011_data *plat = uap->port.dev->platform_data;
240 struct dma_slave_config tx_conf = {
241 .dst_addr = uap->port.mapbase + UART01x_DR,
242 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
243 .direction = DMA_TO_DEVICE,
244 .dst_maxburst = uap->fifosize >> 1,
245 };
246 struct dma_chan *chan;
247 dma_cap_mask_t mask;
248
249 /* We need platform data */
250 if (!plat || !plat->dma_filter) {
251 dev_info(uap->port.dev, "no DMA platform data\n");
252 return;
253 }
254
255 /* Try to acquire a generic DMA engine slave TX channel */
256 dma_cap_zero(mask);
257 dma_cap_set(DMA_SLAVE, mask);
258
259 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param);
260 if (!chan) {
261 dev_err(uap->port.dev, "no TX DMA channel!\n");
262 return;
263 }
264
265 dmaengine_slave_config(chan, &tx_conf);
266 uap->dmatx.chan = chan;
267
268 dev_info(uap->port.dev, "DMA channel TX %s\n",
269 dma_chan_name(uap->dmatx.chan));
270
271 /* Optionally make use of an RX channel as well */
272 if (plat->dma_rx_param) {
273 struct dma_slave_config rx_conf = {
274 .src_addr = uap->port.mapbase + UART01x_DR,
275 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
276 .direction = DMA_FROM_DEVICE,
277 .src_maxburst = uap->fifosize >> 1,
278 };
279
280 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
281 if (!chan) {
282 dev_err(uap->port.dev, "no RX DMA channel!\n");
283 return;
284 }
285
286 dmaengine_slave_config(chan, &rx_conf);
287 uap->dmarx.chan = chan;
288
289 dev_info(uap->port.dev, "DMA channel RX %s\n",
290 dma_chan_name(uap->dmarx.chan));
291 }
292 }
293
294 #ifndef MODULE
295 /*
296 * Stack up the UARTs and let the above initcall be done at device
297 * initcall time, because the serial driver is called as an arch
298 * initcall, and at this time the DMA subsystem is not yet registered.
299 * At this point the driver will switch over to using DMA where desired.
300 */
301 struct dma_uap {
302 struct list_head node;
303 struct uart_amba_port *uap;
304 };
305
306 static LIST_HEAD(pl011_dma_uarts);
307
308 static int __init pl011_dma_initcall(void)
309 {
310 struct list_head *node, *tmp;
311
312 list_for_each_safe(node, tmp, &pl011_dma_uarts) {
313 struct dma_uap *dmau = list_entry(node, struct dma_uap, node);
314 pl011_dma_probe_initcall(dmau->uap);
315 list_del(node);
316 kfree(dmau);
317 }
318 return 0;
319 }
320
321 device_initcall(pl011_dma_initcall);
322
323 static void pl011_dma_probe(struct uart_amba_port *uap)
324 {
325 struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL);
326 if (dmau) {
327 dmau->uap = uap;
328 list_add_tail(&dmau->node, &pl011_dma_uarts);
329 }
330 }
331 #else
332 static void pl011_dma_probe(struct uart_amba_port *uap)
333 {
334 pl011_dma_probe_initcall(uap);
335 }
336 #endif
337
338 static void pl011_dma_remove(struct uart_amba_port *uap)
339 {
340 /* TODO: remove the initcall if it has not yet executed */
341 if (uap->dmatx.chan)
342 dma_release_channel(uap->dmatx.chan);
343 if (uap->dmarx.chan)
344 dma_release_channel(uap->dmarx.chan);
345 }
346
347 /* Forward declare this for the refill routine */
348 static int pl011_dma_tx_refill(struct uart_amba_port *uap);
349
350 /*
351 * The current DMA TX buffer has been sent.
352 * Try to queue up another DMA buffer.
353 */
354 static void pl011_dma_tx_callback(void *data)
355 {
356 struct uart_amba_port *uap = data;
357 struct pl011_dmatx_data *dmatx = &uap->dmatx;
358 unsigned long flags;
359 u16 dmacr;
360
361 spin_lock_irqsave(&uap->port.lock, flags);
362 if (uap->dmatx.queued)
363 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
364 DMA_TO_DEVICE);
365
366 dmacr = uap->dmacr;
367 uap->dmacr = dmacr & ~UART011_TXDMAE;
368 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
369
370 /*
371 * If TX DMA was disabled, it means that we've stopped the DMA for
372 * some reason (eg, XOFF received, or we want to send an X-char.)
373 *
374 * Note: we need to be careful here of a potential race between DMA
375 * and the rest of the driver - if the driver disables TX DMA while
376 * a TX buffer completing, we must update the tx queued status to
377 * get further refills (hence we check dmacr).
378 */
379 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
380 uart_circ_empty(&uap->port.state->xmit)) {
381 uap->dmatx.queued = false;
382 spin_unlock_irqrestore(&uap->port.lock, flags);
383 return;
384 }
385
386 if (pl011_dma_tx_refill(uap) <= 0) {
387 /*
388 * We didn't queue a DMA buffer for some reason, but we
389 * have data pending to be sent. Re-enable the TX IRQ.
390 */
391 uap->im |= UART011_TXIM;
392 writew(uap->im, uap->port.membase + UART011_IMSC);
393 }
394 spin_unlock_irqrestore(&uap->port.lock, flags);
395 }
396
397 /*
398 * Try to refill the TX DMA buffer.
399 * Locking: called with port lock held and IRQs disabled.
400 * Returns:
401 * 1 if we queued up a TX DMA buffer.
402 * 0 if we didn't want to handle this by DMA
403 * <0 on error
404 */
405 static int pl011_dma_tx_refill(struct uart_amba_port *uap)
406 {
407 struct pl011_dmatx_data *dmatx = &uap->dmatx;
408 struct dma_chan *chan = dmatx->chan;
409 struct dma_device *dma_dev = chan->device;
410 struct dma_async_tx_descriptor *desc;
411 struct circ_buf *xmit = &uap->port.state->xmit;
412 unsigned int count;
413
414 /*
415 * Try to avoid the overhead involved in using DMA if the
416 * transaction fits in the first half of the FIFO, by using
417 * the standard interrupt handling. This ensures that we
418 * issue a uart_write_wakeup() at the appropriate time.
419 */
420 count = uart_circ_chars_pending(xmit);
421 if (count < (uap->fifosize >> 1)) {
422 uap->dmatx.queued = false;
423 return 0;
424 }
425
426 /*
427 * Bodge: don't send the last character by DMA, as this
428 * will prevent XON from notifying us to restart DMA.
429 */
430 count -= 1;
431
432 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
433 if (count > PL011_DMA_BUFFER_SIZE)
434 count = PL011_DMA_BUFFER_SIZE;
435
436 if (xmit->tail < xmit->head)
437 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
438 else {
439 size_t first = UART_XMIT_SIZE - xmit->tail;
440 size_t second = xmit->head;
441
442 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
443 if (second)
444 memcpy(&dmatx->buf[first], &xmit->buf[0], second);
445 }
446
447 dmatx->sg.length = count;
448
449 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
450 uap->dmatx.queued = false;
451 dev_dbg(uap->port.dev, "unable to map TX DMA\n");
452 return -EBUSY;
453 }
454
455 desc = dma_dev->device_prep_slave_sg(chan, &dmatx->sg, 1, DMA_TO_DEVICE,
456 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
457 if (!desc) {
458 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
459 uap->dmatx.queued = false;
460 /*
461 * If DMA cannot be used right now, we complete this
462 * transaction via IRQ and let the TTY layer retry.
463 */
464 dev_dbg(uap->port.dev, "TX DMA busy\n");
465 return -EBUSY;
466 }
467
468 /* Some data to go along to the callback */
469 desc->callback = pl011_dma_tx_callback;
470 desc->callback_param = uap;
471
472 /* All errors should happen at prepare time */
473 dmaengine_submit(desc);
474
475 /* Fire the DMA transaction */
476 dma_dev->device_issue_pending(chan);
477
478 uap->dmacr |= UART011_TXDMAE;
479 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
480 uap->dmatx.queued = true;
481
482 /*
483 * Now we know that DMA will fire, so advance the ring buffer
484 * with the stuff we just dispatched.
485 */
486 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
487 uap->port.icount.tx += count;
488
489 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
490 uart_write_wakeup(&uap->port);
491
492 return 1;
493 }
494
495 /*
496 * We received a transmit interrupt without a pending X-char but with
497 * pending characters.
498 * Locking: called with port lock held and IRQs disabled.
499 * Returns:
500 * false if we want to use PIO to transmit
501 * true if we queued a DMA buffer
502 */
503 static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
504 {
505 if (!uap->using_tx_dma)
506 return false;
507
508 /*
509 * If we already have a TX buffer queued, but received a
510 * TX interrupt, it will be because we've just sent an X-char.
511 * Ensure the TX DMA is enabled and the TX IRQ is disabled.
512 */
513 if (uap->dmatx.queued) {
514 uap->dmacr |= UART011_TXDMAE;
515 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
516 uap->im &= ~UART011_TXIM;
517 writew(uap->im, uap->port.membase + UART011_IMSC);
518 return true;
519 }
520
521 /*
522 * We don't have a TX buffer queued, so try to queue one.
523 * If we succesfully queued a buffer, mask the TX IRQ.
524 */
525 if (pl011_dma_tx_refill(uap) > 0) {
526 uap->im &= ~UART011_TXIM;
527 writew(uap->im, uap->port.membase + UART011_IMSC);
528 return true;
529 }
530 return false;
531 }
532
533 /*
534 * Stop the DMA transmit (eg, due to received XOFF).
535 * Locking: called with port lock held and IRQs disabled.
536 */
537 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
538 {
539 if (uap->dmatx.queued) {
540 uap->dmacr &= ~UART011_TXDMAE;
541 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
542 }
543 }
544
545 /*
546 * Try to start a DMA transmit, or in the case of an XON/OFF
547 * character queued for send, try to get that character out ASAP.
548 * Locking: called with port lock held and IRQs disabled.
549 * Returns:
550 * false if we want the TX IRQ to be enabled
551 * true if we have a buffer queued
552 */
553 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
554 {
555 u16 dmacr;
556
557 if (!uap->using_tx_dma)
558 return false;
559
560 if (!uap->port.x_char) {
561 /* no X-char, try to push chars out in DMA mode */
562 bool ret = true;
563
564 if (!uap->dmatx.queued) {
565 if (pl011_dma_tx_refill(uap) > 0) {
566 uap->im &= ~UART011_TXIM;
567 ret = true;
568 } else {
569 uap->im |= UART011_TXIM;
570 ret = false;
571 }
572 writew(uap->im, uap->port.membase + UART011_IMSC);
573 } else if (!(uap->dmacr & UART011_TXDMAE)) {
574 uap->dmacr |= UART011_TXDMAE;
575 writew(uap->dmacr,
576 uap->port.membase + UART011_DMACR);
577 }
578 return ret;
579 }
580
581 /*
582 * We have an X-char to send. Disable DMA to prevent it loading
583 * the TX fifo, and then see if we can stuff it into the FIFO.
584 */
585 dmacr = uap->dmacr;
586 uap->dmacr &= ~UART011_TXDMAE;
587 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
588
589 if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) {
590 /*
591 * No space in the FIFO, so enable the transmit interrupt
592 * so we know when there is space. Note that once we've
593 * loaded the character, we should just re-enable DMA.
594 */
595 return false;
596 }
597
598 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
599 uap->port.icount.tx++;
600 uap->port.x_char = 0;
601
602 /* Success - restore the DMA state */
603 uap->dmacr = dmacr;
604 writew(dmacr, uap->port.membase + UART011_DMACR);
605
606 return true;
607 }
608
609 /*
610 * Flush the transmit buffer.
611 * Locking: called with port lock held and IRQs disabled.
612 */
613 static void pl011_dma_flush_buffer(struct uart_port *port)
614 {
615 struct uart_amba_port *uap = (struct uart_amba_port *)port;
616
617 if (!uap->using_tx_dma)
618 return;
619
620 /* Avoid deadlock with the DMA engine callback */
621 spin_unlock(&uap->port.lock);
622 dmaengine_terminate_all(uap->dmatx.chan);
623 spin_lock(&uap->port.lock);
624 if (uap->dmatx.queued) {
625 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
626 DMA_TO_DEVICE);
627 uap->dmatx.queued = false;
628 uap->dmacr &= ~UART011_TXDMAE;
629 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
630 }
631 }
632
633 static void pl011_dma_rx_callback(void *data);
634
635 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
636 {
637 struct dma_chan *rxchan = uap->dmarx.chan;
638 struct dma_device *dma_dev;
639 struct pl011_dmarx_data *dmarx = &uap->dmarx;
640 struct dma_async_tx_descriptor *desc;
641 struct pl011_sgbuf *sgbuf;
642
643 if (!rxchan)
644 return -EIO;
645
646 /* Start the RX DMA job */
647 sgbuf = uap->dmarx.use_buf_b ?
648 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
649 dma_dev = rxchan->device;
650 desc = rxchan->device->device_prep_slave_sg(rxchan, &sgbuf->sg, 1,
651 DMA_FROM_DEVICE,
652 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
653 /*
654 * If the DMA engine is busy and cannot prepare a
655 * channel, no big deal, the driver will fall back
656 * to interrupt mode as a result of this error code.
657 */
658 if (!desc) {
659 uap->dmarx.running = false;
660 dmaengine_terminate_all(rxchan);
661 return -EBUSY;
662 }
663
664 /* Some data to go along to the callback */
665 desc->callback = pl011_dma_rx_callback;
666 desc->callback_param = uap;
667 dmarx->cookie = dmaengine_submit(desc);
668 dma_async_issue_pending(rxchan);
669
670 uap->dmacr |= UART011_RXDMAE;
671 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
672 uap->dmarx.running = true;
673
674 uap->im &= ~UART011_RXIM;
675 writew(uap->im, uap->port.membase + UART011_IMSC);
676
677 return 0;
678 }
679
680 /*
681 * This is called when either the DMA job is complete, or
682 * the FIFO timeout interrupt occurred. This must be called
683 * with the port spinlock uap->port.lock held.
684 */
685 static void pl011_dma_rx_chars(struct uart_amba_port *uap,
686 u32 pending, bool use_buf_b,
687 bool readfifo)
688 {
689 struct tty_struct *tty = uap->port.state->port.tty;
690 struct pl011_sgbuf *sgbuf = use_buf_b ?
691 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
692 struct device *dev = uap->dmarx.chan->device->dev;
693 int dma_count = 0;
694 u32 fifotaken = 0; /* only used for vdbg() */
695
696 /* Pick everything from the DMA first */
697 if (pending) {
698 /* Sync in buffer */
699 dma_sync_sg_for_cpu(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
700
701 /*
702 * First take all chars in the DMA pipe, then look in the FIFO.
703 * Note that tty_insert_flip_buf() tries to take as many chars
704 * as it can.
705 */
706 dma_count = tty_insert_flip_string(uap->port.state->port.tty,
707 sgbuf->buf, pending);
708
709 /* Return buffer to device */
710 dma_sync_sg_for_device(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
711
712 uap->port.icount.rx += dma_count;
713 if (dma_count < pending)
714 dev_warn(uap->port.dev,
715 "couldn't insert all characters (TTY is full?)\n");
716 }
717
718 /*
719 * Only continue with trying to read the FIFO if all DMA chars have
720 * been taken first.
721 */
722 if (dma_count == pending && readfifo) {
723 /* Clear any error flags */
724 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
725 uap->port.membase + UART011_ICR);
726
727 /*
728 * If we read all the DMA'd characters, and we had an
729 * incomplete buffer, that could be due to an rx error, or
730 * maybe we just timed out. Read any pending chars and check
731 * the error status.
732 *
733 * Error conditions will only occur in the FIFO, these will
734 * trigger an immediate interrupt and stop the DMA job, so we
735 * will always find the error in the FIFO, never in the DMA
736 * buffer.
737 */
738 fifotaken = pl011_fifo_to_tty(uap);
739 }
740
741 spin_unlock(&uap->port.lock);
742 dev_vdbg(uap->port.dev,
743 "Took %d chars from DMA buffer and %d chars from the FIFO\n",
744 dma_count, fifotaken);
745 tty_flip_buffer_push(tty);
746 spin_lock(&uap->port.lock);
747 }
748
749 static void pl011_dma_rx_irq(struct uart_amba_port *uap)
750 {
751 struct pl011_dmarx_data *dmarx = &uap->dmarx;
752 struct dma_chan *rxchan = dmarx->chan;
753 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
754 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
755 size_t pending;
756 struct dma_tx_state state;
757 enum dma_status dmastat;
758
759 /*
760 * Pause the transfer so we can trust the current counter,
761 * do this before we pause the PL011 block, else we may
762 * overflow the FIFO.
763 */
764 if (dmaengine_pause(rxchan))
765 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
766 dmastat = rxchan->device->device_tx_status(rxchan,
767 dmarx->cookie, &state);
768 if (dmastat != DMA_PAUSED)
769 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
770
771 /* Disable RX DMA - incoming data will wait in the FIFO */
772 uap->dmacr &= ~UART011_RXDMAE;
773 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
774 uap->dmarx.running = false;
775
776 pending = sgbuf->sg.length - state.residue;
777 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
778 /* Then we terminate the transfer - we now know our residue */
779 dmaengine_terminate_all(rxchan);
780
781 /*
782 * This will take the chars we have so far and insert
783 * into the framework.
784 */
785 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
786
787 /* Switch buffer & re-trigger DMA job */
788 dmarx->use_buf_b = !dmarx->use_buf_b;
789 if (pl011_dma_rx_trigger_dma(uap)) {
790 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
791 "fall back to interrupt mode\n");
792 uap->im |= UART011_RXIM;
793 writew(uap->im, uap->port.membase + UART011_IMSC);
794 }
795 }
796
797 static void pl011_dma_rx_callback(void *data)
798 {
799 struct uart_amba_port *uap = data;
800 struct pl011_dmarx_data *dmarx = &uap->dmarx;
801 bool lastbuf = dmarx->use_buf_b;
802 int ret;
803
804 /*
805 * This completion interrupt occurs typically when the
806 * RX buffer is totally stuffed but no timeout has yet
807 * occurred. When that happens, we just want the RX
808 * routine to flush out the secondary DMA buffer while
809 * we immediately trigger the next DMA job.
810 */
811 spin_lock_irq(&uap->port.lock);
812 uap->dmarx.running = false;
813 dmarx->use_buf_b = !lastbuf;
814 ret = pl011_dma_rx_trigger_dma(uap);
815
816 pl011_dma_rx_chars(uap, PL011_DMA_BUFFER_SIZE, lastbuf, false);
817 spin_unlock_irq(&uap->port.lock);
818 /*
819 * Do this check after we picked the DMA chars so we don't
820 * get some IRQ immediately from RX.
821 */
822 if (ret) {
823 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
824 "fall back to interrupt mode\n");
825 uap->im |= UART011_RXIM;
826 writew(uap->im, uap->port.membase + UART011_IMSC);
827 }
828 }
829
830 /*
831 * Stop accepting received characters, when we're shutting down or
832 * suspending this port.
833 * Locking: called with port lock held and IRQs disabled.
834 */
835 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
836 {
837 /* FIXME. Just disable the DMA enable */
838 uap->dmacr &= ~UART011_RXDMAE;
839 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
840 }
841
842 static void pl011_dma_startup(struct uart_amba_port *uap)
843 {
844 int ret;
845
846 if (!uap->dmatx.chan)
847 return;
848
849 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
850 if (!uap->dmatx.buf) {
851 dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
852 uap->port.fifosize = uap->fifosize;
853 return;
854 }
855
856 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
857
858 /* The DMA buffer is now the FIFO the TTY subsystem can use */
859 uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
860 uap->using_tx_dma = true;
861
862 if (!uap->dmarx.chan)
863 goto skip_rx;
864
865 /* Allocate and map DMA RX buffers */
866 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
867 DMA_FROM_DEVICE);
868 if (ret) {
869 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
870 "RX buffer A", ret);
871 goto skip_rx;
872 }
873
874 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
875 DMA_FROM_DEVICE);
876 if (ret) {
877 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
878 "RX buffer B", ret);
879 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
880 DMA_FROM_DEVICE);
881 goto skip_rx;
882 }
883
884 uap->using_rx_dma = true;
885
886 skip_rx:
887 /* Turn on DMA error (RX/TX will be enabled on demand) */
888 uap->dmacr |= UART011_DMAONERR;
889 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
890
891 /*
892 * ST Micro variants has some specific dma burst threshold
893 * compensation. Set this to 16 bytes, so burst will only
894 * be issued above/below 16 bytes.
895 */
896 if (uap->vendor->dma_threshold)
897 writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
898 uap->port.membase + ST_UART011_DMAWM);
899
900 if (uap->using_rx_dma) {
901 if (pl011_dma_rx_trigger_dma(uap))
902 dev_dbg(uap->port.dev, "could not trigger initial "
903 "RX DMA job, fall back to interrupt mode\n");
904 }
905 }
906
907 static void pl011_dma_shutdown(struct uart_amba_port *uap)
908 {
909 if (!(uap->using_tx_dma || uap->using_rx_dma))
910 return;
911
912 /* Disable RX and TX DMA */
913 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
914 barrier();
915
916 spin_lock_irq(&uap->port.lock);
917 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
918 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
919 spin_unlock_irq(&uap->port.lock);
920
921 if (uap->using_tx_dma) {
922 /* In theory, this should already be done by pl011_dma_flush_buffer */
923 dmaengine_terminate_all(uap->dmatx.chan);
924 if (uap->dmatx.queued) {
925 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
926 DMA_TO_DEVICE);
927 uap->dmatx.queued = false;
928 }
929
930 kfree(uap->dmatx.buf);
931 uap->using_tx_dma = false;
932 }
933
934 if (uap->using_rx_dma) {
935 dmaengine_terminate_all(uap->dmarx.chan);
936 /* Clean up the RX DMA */
937 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
938 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
939 uap->using_rx_dma = false;
940 }
941 }
942
943 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
944 {
945 return uap->using_rx_dma;
946 }
947
948 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
949 {
950 return uap->using_rx_dma && uap->dmarx.running;
951 }
952
953
954 #else
955 /* Blank functions if the DMA engine is not available */
956 static inline void pl011_dma_probe(struct uart_amba_port *uap)
957 {
958 }
959
960 static inline void pl011_dma_remove(struct uart_amba_port *uap)
961 {
962 }
963
964 static inline void pl011_dma_startup(struct uart_amba_port *uap)
965 {
966 }
967
968 static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
969 {
970 }
971
972 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
973 {
974 return false;
975 }
976
977 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
978 {
979 }
980
981 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
982 {
983 return false;
984 }
985
986 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
987 {
988 }
989
990 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
991 {
992 }
993
994 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
995 {
996 return -EIO;
997 }
998
999 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1000 {
1001 return false;
1002 }
1003
1004 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1005 {
1006 return false;
1007 }
1008
1009 #define pl011_dma_flush_buffer NULL
1010 #endif
1011
1012
1013 static void pl011_stop_tx(struct uart_port *port)
1014 {
1015 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1016
1017 uap->im &= ~UART011_TXIM;
1018 writew(uap->im, uap->port.membase + UART011_IMSC);
1019 pl011_dma_tx_stop(uap);
1020 }
1021
1022 static void pl011_start_tx(struct uart_port *port)
1023 {
1024 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1025
1026 if (!pl011_dma_tx_start(uap)) {
1027 uap->im |= UART011_TXIM;
1028 writew(uap->im, uap->port.membase + UART011_IMSC);
1029 }
1030 }
1031
1032 static void pl011_stop_rx(struct uart_port *port)
1033 {
1034 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1035
1036 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
1037 UART011_PEIM|UART011_BEIM|UART011_OEIM);
1038 writew(uap->im, uap->port.membase + UART011_IMSC);
1039
1040 pl011_dma_rx_stop(uap);
1041 }
1042
1043 static void pl011_enable_ms(struct uart_port *port)
1044 {
1045 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1046
1047 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
1048 writew(uap->im, uap->port.membase + UART011_IMSC);
1049 }
1050
1051 static void pl011_rx_chars(struct uart_amba_port *uap)
1052 {
1053 struct tty_struct *tty = uap->port.state->port.tty;
1054
1055 pl011_fifo_to_tty(uap);
1056
1057 spin_unlock(&uap->port.lock);
1058 tty_flip_buffer_push(tty);
1059 /*
1060 * If we were temporarily out of DMA mode for a while,
1061 * attempt to switch back to DMA mode again.
1062 */
1063 if (pl011_dma_rx_available(uap)) {
1064 if (pl011_dma_rx_trigger_dma(uap)) {
1065 dev_dbg(uap->port.dev, "could not trigger RX DMA job "
1066 "fall back to interrupt mode again\n");
1067 uap->im |= UART011_RXIM;
1068 } else
1069 uap->im &= ~UART011_RXIM;
1070 writew(uap->im, uap->port.membase + UART011_IMSC);
1071 }
1072 spin_lock(&uap->port.lock);
1073 }
1074
1075 static void pl011_tx_chars(struct uart_amba_port *uap)
1076 {
1077 struct circ_buf *xmit = &uap->port.state->xmit;
1078 int count;
1079
1080 if (uap->port.x_char) {
1081 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
1082 uap->port.icount.tx++;
1083 uap->port.x_char = 0;
1084 return;
1085 }
1086 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
1087 pl011_stop_tx(&uap->port);
1088 return;
1089 }
1090
1091 /* If we are using DMA mode, try to send some characters. */
1092 if (pl011_dma_tx_irq(uap))
1093 return;
1094
1095 count = uap->fifosize >> 1;
1096 do {
1097 writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
1098 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1099 uap->port.icount.tx++;
1100 if (uart_circ_empty(xmit))
1101 break;
1102 } while (--count > 0);
1103
1104 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1105 uart_write_wakeup(&uap->port);
1106
1107 if (uart_circ_empty(xmit))
1108 pl011_stop_tx(&uap->port);
1109 }
1110
1111 static void pl011_modem_status(struct uart_amba_port *uap)
1112 {
1113 unsigned int status, delta;
1114
1115 status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1116
1117 delta = status ^ uap->old_status;
1118 uap->old_status = status;
1119
1120 if (!delta)
1121 return;
1122
1123 if (delta & UART01x_FR_DCD)
1124 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
1125
1126 if (delta & UART01x_FR_DSR)
1127 uap->port.icount.dsr++;
1128
1129 if (delta & UART01x_FR_CTS)
1130 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
1131
1132 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
1133 }
1134
1135 static irqreturn_t pl011_int(int irq, void *dev_id)
1136 {
1137 struct uart_amba_port *uap = dev_id;
1138 unsigned long flags;
1139 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
1140 int handled = 0;
1141
1142 spin_lock_irqsave(&uap->port.lock, flags);
1143
1144 status = readw(uap->port.membase + UART011_MIS);
1145 if (status) {
1146 do {
1147 writew(status & ~(UART011_TXIS|UART011_RTIS|
1148 UART011_RXIS),
1149 uap->port.membase + UART011_ICR);
1150
1151 if (status & (UART011_RTIS|UART011_RXIS)) {
1152 if (pl011_dma_rx_running(uap))
1153 pl011_dma_rx_irq(uap);
1154 else
1155 pl011_rx_chars(uap);
1156 }
1157 if (status & (UART011_DSRMIS|UART011_DCDMIS|
1158 UART011_CTSMIS|UART011_RIMIS))
1159 pl011_modem_status(uap);
1160 if (status & UART011_TXIS)
1161 pl011_tx_chars(uap);
1162
1163 if (pass_counter-- == 0)
1164 break;
1165
1166 status = readw(uap->port.membase + UART011_MIS);
1167 } while (status != 0);
1168 handled = 1;
1169 }
1170
1171 spin_unlock_irqrestore(&uap->port.lock, flags);
1172
1173 return IRQ_RETVAL(handled);
1174 }
1175
1176 static unsigned int pl01x_tx_empty(struct uart_port *port)
1177 {
1178 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1179 unsigned int status = readw(uap->port.membase + UART01x_FR);
1180 return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
1181 }
1182
1183 static unsigned int pl01x_get_mctrl(struct uart_port *port)
1184 {
1185 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1186 unsigned int result = 0;
1187 unsigned int status = readw(uap->port.membase + UART01x_FR);
1188
1189 #define TIOCMBIT(uartbit, tiocmbit) \
1190 if (status & uartbit) \
1191 result |= tiocmbit
1192
1193 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
1194 TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
1195 TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
1196 TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
1197 #undef TIOCMBIT
1198 return result;
1199 }
1200
1201 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
1202 {
1203 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1204 unsigned int cr;
1205
1206 cr = readw(uap->port.membase + UART011_CR);
1207
1208 #define TIOCMBIT(tiocmbit, uartbit) \
1209 if (mctrl & tiocmbit) \
1210 cr |= uartbit; \
1211 else \
1212 cr &= ~uartbit
1213
1214 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
1215 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
1216 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
1217 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
1218 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
1219
1220 if (uap->autorts) {
1221 /* We need to disable auto-RTS if we want to turn RTS off */
1222 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
1223 }
1224 #undef TIOCMBIT
1225
1226 writew(cr, uap->port.membase + UART011_CR);
1227 }
1228
1229 static void pl011_break_ctl(struct uart_port *port, int break_state)
1230 {
1231 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1232 unsigned long flags;
1233 unsigned int lcr_h;
1234
1235 spin_lock_irqsave(&uap->port.lock, flags);
1236 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1237 if (break_state == -1)
1238 lcr_h |= UART01x_LCRH_BRK;
1239 else
1240 lcr_h &= ~UART01x_LCRH_BRK;
1241 writew(lcr_h, uap->port.membase + uap->lcrh_tx);
1242 spin_unlock_irqrestore(&uap->port.lock, flags);
1243 }
1244
1245 #ifdef CONFIG_CONSOLE_POLL
1246 static int pl010_get_poll_char(struct uart_port *port)
1247 {
1248 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1249 unsigned int status;
1250
1251 status = readw(uap->port.membase + UART01x_FR);
1252 if (status & UART01x_FR_RXFE)
1253 return NO_POLL_CHAR;
1254
1255 return readw(uap->port.membase + UART01x_DR);
1256 }
1257
1258 static void pl010_put_poll_char(struct uart_port *port,
1259 unsigned char ch)
1260 {
1261 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1262
1263 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1264 barrier();
1265
1266 writew(ch, uap->port.membase + UART01x_DR);
1267 }
1268
1269 #endif /* CONFIG_CONSOLE_POLL */
1270
1271 static int pl011_startup(struct uart_port *port)
1272 {
1273 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1274 unsigned int cr;
1275 int retval;
1276
1277 /*
1278 * Try to enable the clock producer.
1279 */
1280 retval = clk_enable(uap->clk);
1281 if (retval)
1282 goto out;
1283
1284 uap->port.uartclk = clk_get_rate(uap->clk);
1285
1286 /*
1287 * Allocate the IRQ
1288 */
1289 retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
1290 if (retval)
1291 goto clk_dis;
1292
1293 writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
1294
1295 /*
1296 * Provoke TX FIFO interrupt into asserting.
1297 */
1298 cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE;
1299 writew(cr, uap->port.membase + UART011_CR);
1300 writew(0, uap->port.membase + UART011_FBRD);
1301 writew(1, uap->port.membase + UART011_IBRD);
1302 writew(0, uap->port.membase + uap->lcrh_rx);
1303 if (uap->lcrh_tx != uap->lcrh_rx) {
1304 int i;
1305 /*
1306 * Wait 10 PCLKs before writing LCRH_TX register,
1307 * to get this delay write read only register 10 times
1308 */
1309 for (i = 0; i < 10; ++i)
1310 writew(0xff, uap->port.membase + UART011_MIS);
1311 writew(0, uap->port.membase + uap->lcrh_tx);
1312 }
1313 writew(0, uap->port.membase + UART01x_DR);
1314 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
1315 barrier();
1316
1317 cr = UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
1318 writew(cr, uap->port.membase + UART011_CR);
1319
1320 /* Clear pending error interrupts */
1321 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
1322 uap->port.membase + UART011_ICR);
1323
1324 /*
1325 * initialise the old status of the modem signals
1326 */
1327 uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1328
1329 /* Startup DMA */
1330 pl011_dma_startup(uap);
1331
1332 /*
1333 * Finally, enable interrupts, only timeouts when using DMA
1334 * if initial RX DMA job failed, start in interrupt mode
1335 * as well.
1336 */
1337 spin_lock_irq(&uap->port.lock);
1338 uap->im = UART011_RTIM;
1339 if (!pl011_dma_rx_running(uap))
1340 uap->im |= UART011_RXIM;
1341 writew(uap->im, uap->port.membase + UART011_IMSC);
1342 spin_unlock_irq(&uap->port.lock);
1343
1344 return 0;
1345
1346 clk_dis:
1347 clk_disable(uap->clk);
1348 out:
1349 return retval;
1350 }
1351
1352 static void pl011_shutdown_channel(struct uart_amba_port *uap,
1353 unsigned int lcrh)
1354 {
1355 unsigned long val;
1356
1357 val = readw(uap->port.membase + lcrh);
1358 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
1359 writew(val, uap->port.membase + lcrh);
1360 }
1361
1362 static void pl011_shutdown(struct uart_port *port)
1363 {
1364 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1365
1366 /*
1367 * disable all interrupts
1368 */
1369 spin_lock_irq(&uap->port.lock);
1370 uap->im = 0;
1371 writew(uap->im, uap->port.membase + UART011_IMSC);
1372 writew(0xffff, uap->port.membase + UART011_ICR);
1373 spin_unlock_irq(&uap->port.lock);
1374
1375 pl011_dma_shutdown(uap);
1376
1377 /*
1378 * Free the interrupt
1379 */
1380 free_irq(uap->port.irq, uap);
1381
1382 /*
1383 * disable the port
1384 */
1385 uap->autorts = false;
1386 writew(UART01x_CR_UARTEN | UART011_CR_TXE, uap->port.membase + UART011_CR);
1387
1388 /*
1389 * disable break condition and fifos
1390 */
1391 pl011_shutdown_channel(uap, uap->lcrh_rx);
1392 if (uap->lcrh_rx != uap->lcrh_tx)
1393 pl011_shutdown_channel(uap, uap->lcrh_tx);
1394
1395 /*
1396 * Shut down the clock producer
1397 */
1398 clk_disable(uap->clk);
1399 }
1400
1401 static void
1402 pl011_set_termios(struct uart_port *port, struct ktermios *termios,
1403 struct ktermios *old)
1404 {
1405 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1406 unsigned int lcr_h, old_cr;
1407 unsigned long flags;
1408 unsigned int baud, quot, clkdiv;
1409
1410 if (uap->vendor->oversampling)
1411 clkdiv = 8;
1412 else
1413 clkdiv = 16;
1414
1415 /*
1416 * Ask the core to calculate the divisor for us.
1417 */
1418 baud = uart_get_baud_rate(port, termios, old, 0,
1419 port->uartclk / clkdiv);
1420
1421 if (baud > port->uartclk/16)
1422 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
1423 else
1424 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
1425
1426 switch (termios->c_cflag & CSIZE) {
1427 case CS5:
1428 lcr_h = UART01x_LCRH_WLEN_5;
1429 break;
1430 case CS6:
1431 lcr_h = UART01x_LCRH_WLEN_6;
1432 break;
1433 case CS7:
1434 lcr_h = UART01x_LCRH_WLEN_7;
1435 break;
1436 default: // CS8
1437 lcr_h = UART01x_LCRH_WLEN_8;
1438 break;
1439 }
1440 if (termios->c_cflag & CSTOPB)
1441 lcr_h |= UART01x_LCRH_STP2;
1442 if (termios->c_cflag & PARENB) {
1443 lcr_h |= UART01x_LCRH_PEN;
1444 if (!(termios->c_cflag & PARODD))
1445 lcr_h |= UART01x_LCRH_EPS;
1446 }
1447 if (uap->fifosize > 1)
1448 lcr_h |= UART01x_LCRH_FEN;
1449
1450 spin_lock_irqsave(&port->lock, flags);
1451
1452 /*
1453 * Update the per-port timeout.
1454 */
1455 uart_update_timeout(port, termios->c_cflag, baud);
1456
1457 port->read_status_mask = UART011_DR_OE | 255;
1458 if (termios->c_iflag & INPCK)
1459 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
1460 if (termios->c_iflag & (BRKINT | PARMRK))
1461 port->read_status_mask |= UART011_DR_BE;
1462
1463 /*
1464 * Characters to ignore
1465 */
1466 port->ignore_status_mask = 0;
1467 if (termios->c_iflag & IGNPAR)
1468 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
1469 if (termios->c_iflag & IGNBRK) {
1470 port->ignore_status_mask |= UART011_DR_BE;
1471 /*
1472 * If we're ignoring parity and break indicators,
1473 * ignore overruns too (for real raw support).
1474 */
1475 if (termios->c_iflag & IGNPAR)
1476 port->ignore_status_mask |= UART011_DR_OE;
1477 }
1478
1479 /*
1480 * Ignore all characters if CREAD is not set.
1481 */
1482 if ((termios->c_cflag & CREAD) == 0)
1483 port->ignore_status_mask |= UART_DUMMY_DR_RX;
1484
1485 if (UART_ENABLE_MS(port, termios->c_cflag))
1486 pl011_enable_ms(port);
1487
1488 /* first, disable everything */
1489 old_cr = readw(port->membase + UART011_CR);
1490 writew(0, port->membase + UART011_CR);
1491
1492 if (termios->c_cflag & CRTSCTS) {
1493 if (old_cr & UART011_CR_RTS)
1494 old_cr |= UART011_CR_RTSEN;
1495
1496 old_cr |= UART011_CR_CTSEN;
1497 uap->autorts = true;
1498 } else {
1499 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
1500 uap->autorts = false;
1501 }
1502
1503 if (uap->vendor->oversampling) {
1504 if (baud > port->uartclk / 16)
1505 old_cr |= ST_UART011_CR_OVSFACT;
1506 else
1507 old_cr &= ~ST_UART011_CR_OVSFACT;
1508 }
1509
1510 /* Set baud rate */
1511 writew(quot & 0x3f, port->membase + UART011_FBRD);
1512 writew(quot >> 6, port->membase + UART011_IBRD);
1513
1514 /*
1515 * ----------v----------v----------v----------v-----
1516 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
1517 * ----------^----------^----------^----------^-----
1518 */
1519 writew(lcr_h, port->membase + uap->lcrh_rx);
1520 if (uap->lcrh_rx != uap->lcrh_tx) {
1521 int i;
1522 /*
1523 * Wait 10 PCLKs before writing LCRH_TX register,
1524 * to get this delay write read only register 10 times
1525 */
1526 for (i = 0; i < 10; ++i)
1527 writew(0xff, uap->port.membase + UART011_MIS);
1528 writew(lcr_h, port->membase + uap->lcrh_tx);
1529 }
1530 writew(old_cr, port->membase + UART011_CR);
1531
1532 spin_unlock_irqrestore(&port->lock, flags);
1533 }
1534
1535 static const char *pl011_type(struct uart_port *port)
1536 {
1537 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1538 return uap->port.type == PORT_AMBA ? uap->type : NULL;
1539 }
1540
1541 /*
1542 * Release the memory region(s) being used by 'port'
1543 */
1544 static void pl010_release_port(struct uart_port *port)
1545 {
1546 release_mem_region(port->mapbase, SZ_4K);
1547 }
1548
1549 /*
1550 * Request the memory region(s) being used by 'port'
1551 */
1552 static int pl010_request_port(struct uart_port *port)
1553 {
1554 return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
1555 != NULL ? 0 : -EBUSY;
1556 }
1557
1558 /*
1559 * Configure/autoconfigure the port.
1560 */
1561 static void pl010_config_port(struct uart_port *port, int flags)
1562 {
1563 if (flags & UART_CONFIG_TYPE) {
1564 port->type = PORT_AMBA;
1565 pl010_request_port(port);
1566 }
1567 }
1568
1569 /*
1570 * verify the new serial_struct (for TIOCSSERIAL).
1571 */
1572 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
1573 {
1574 int ret = 0;
1575 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
1576 ret = -EINVAL;
1577 if (ser->irq < 0 || ser->irq >= nr_irqs)
1578 ret = -EINVAL;
1579 if (ser->baud_base < 9600)
1580 ret = -EINVAL;
1581 return ret;
1582 }
1583
1584 static struct uart_ops amba_pl011_pops = {
1585 .tx_empty = pl01x_tx_empty,
1586 .set_mctrl = pl011_set_mctrl,
1587 .get_mctrl = pl01x_get_mctrl,
1588 .stop_tx = pl011_stop_tx,
1589 .start_tx = pl011_start_tx,
1590 .stop_rx = pl011_stop_rx,
1591 .enable_ms = pl011_enable_ms,
1592 .break_ctl = pl011_break_ctl,
1593 .startup = pl011_startup,
1594 .shutdown = pl011_shutdown,
1595 .flush_buffer = pl011_dma_flush_buffer,
1596 .set_termios = pl011_set_termios,
1597 .type = pl011_type,
1598 .release_port = pl010_release_port,
1599 .request_port = pl010_request_port,
1600 .config_port = pl010_config_port,
1601 .verify_port = pl010_verify_port,
1602 #ifdef CONFIG_CONSOLE_POLL
1603 .poll_get_char = pl010_get_poll_char,
1604 .poll_put_char = pl010_put_poll_char,
1605 #endif
1606 };
1607
1608 static struct uart_amba_port *amba_ports[UART_NR];
1609
1610 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
1611
1612 static void pl011_console_putchar(struct uart_port *port, int ch)
1613 {
1614 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1615
1616 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1617 barrier();
1618 writew(ch, uap->port.membase + UART01x_DR);
1619 }
1620
1621 static void
1622 pl011_console_write(struct console *co, const char *s, unsigned int count)
1623 {
1624 struct uart_amba_port *uap = amba_ports[co->index];
1625 unsigned int status, old_cr, new_cr;
1626
1627 clk_enable(uap->clk);
1628
1629 /*
1630 * First save the CR then disable the interrupts
1631 */
1632 old_cr = readw(uap->port.membase + UART011_CR);
1633 new_cr = old_cr & ~UART011_CR_CTSEN;
1634 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1635 writew(new_cr, uap->port.membase + UART011_CR);
1636
1637 uart_console_write(&uap->port, s, count, pl011_console_putchar);
1638
1639 /*
1640 * Finally, wait for transmitter to become empty
1641 * and restore the TCR
1642 */
1643 do {
1644 status = readw(uap->port.membase + UART01x_FR);
1645 } while (status & UART01x_FR_BUSY);
1646 writew(old_cr, uap->port.membase + UART011_CR);
1647
1648 clk_disable(uap->clk);
1649 }
1650
1651 static void __init
1652 pl011_console_get_options(struct uart_amba_port *uap, int *baud,
1653 int *parity, int *bits)
1654 {
1655 if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
1656 unsigned int lcr_h, ibrd, fbrd;
1657
1658 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1659
1660 *parity = 'n';
1661 if (lcr_h & UART01x_LCRH_PEN) {
1662 if (lcr_h & UART01x_LCRH_EPS)
1663 *parity = 'e';
1664 else
1665 *parity = 'o';
1666 }
1667
1668 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
1669 *bits = 7;
1670 else
1671 *bits = 8;
1672
1673 ibrd = readw(uap->port.membase + UART011_IBRD);
1674 fbrd = readw(uap->port.membase + UART011_FBRD);
1675
1676 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
1677
1678 if (uap->vendor->oversampling) {
1679 if (readw(uap->port.membase + UART011_CR)
1680 & ST_UART011_CR_OVSFACT)
1681 *baud *= 2;
1682 }
1683 }
1684 }
1685
1686 static int __init pl011_console_setup(struct console *co, char *options)
1687 {
1688 struct uart_amba_port *uap;
1689 int baud = 38400;
1690 int bits = 8;
1691 int parity = 'n';
1692 int flow = 'n';
1693
1694 /*
1695 * Check whether an invalid uart number has been specified, and
1696 * if so, search for the first available port that does have
1697 * console support.
1698 */
1699 if (co->index >= UART_NR)
1700 co->index = 0;
1701 uap = amba_ports[co->index];
1702 if (!uap)
1703 return -ENODEV;
1704
1705 uap->port.uartclk = clk_get_rate(uap->clk);
1706
1707 if (options)
1708 uart_parse_options(options, &baud, &parity, &bits, &flow);
1709 else
1710 pl011_console_get_options(uap, &baud, &parity, &bits);
1711
1712 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
1713 }
1714
1715 static struct uart_driver amba_reg;
1716 static struct console amba_console = {
1717 .name = "ttyAMA",
1718 .write = pl011_console_write,
1719 .device = uart_console_device,
1720 .setup = pl011_console_setup,
1721 .flags = CON_PRINTBUFFER,
1722 .index = -1,
1723 .data = &amba_reg,
1724 };
1725
1726 #define AMBA_CONSOLE (&amba_console)
1727 #else
1728 #define AMBA_CONSOLE NULL
1729 #endif
1730
1731 static struct uart_driver amba_reg = {
1732 .owner = THIS_MODULE,
1733 .driver_name = "ttyAMA",
1734 .dev_name = "ttyAMA",
1735 .major = SERIAL_AMBA_MAJOR,
1736 .minor = SERIAL_AMBA_MINOR,
1737 .nr = UART_NR,
1738 .cons = AMBA_CONSOLE,
1739 };
1740
1741 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
1742 {
1743 struct uart_amba_port *uap;
1744 struct vendor_data *vendor = id->data;
1745 void __iomem *base;
1746 int i, ret;
1747
1748 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1749 if (amba_ports[i] == NULL)
1750 break;
1751
1752 if (i == ARRAY_SIZE(amba_ports)) {
1753 ret = -EBUSY;
1754 goto out;
1755 }
1756
1757 uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
1758 if (uap == NULL) {
1759 ret = -ENOMEM;
1760 goto out;
1761 }
1762
1763 base = ioremap(dev->res.start, resource_size(&dev->res));
1764 if (!base) {
1765 ret = -ENOMEM;
1766 goto free;
1767 }
1768
1769 uap->clk = clk_get(&dev->dev, NULL);
1770 if (IS_ERR(uap->clk)) {
1771 ret = PTR_ERR(uap->clk);
1772 goto unmap;
1773 }
1774
1775 uap->vendor = vendor;
1776 uap->lcrh_rx = vendor->lcrh_rx;
1777 uap->lcrh_tx = vendor->lcrh_tx;
1778 uap->fifosize = vendor->fifosize;
1779 uap->port.dev = &dev->dev;
1780 uap->port.mapbase = dev->res.start;
1781 uap->port.membase = base;
1782 uap->port.iotype = UPIO_MEM;
1783 uap->port.irq = dev->irq[0];
1784 uap->port.fifosize = uap->fifosize;
1785 uap->port.ops = &amba_pl011_pops;
1786 uap->port.flags = UPF_BOOT_AUTOCONF;
1787 uap->port.line = i;
1788 pl011_dma_probe(uap);
1789
1790 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
1791
1792 amba_ports[i] = uap;
1793
1794 amba_set_drvdata(dev, uap);
1795 ret = uart_add_one_port(&amba_reg, &uap->port);
1796 if (ret) {
1797 amba_set_drvdata(dev, NULL);
1798 amba_ports[i] = NULL;
1799 pl011_dma_remove(uap);
1800 clk_put(uap->clk);
1801 unmap:
1802 iounmap(base);
1803 free:
1804 kfree(uap);
1805 }
1806 out:
1807 return ret;
1808 }
1809
1810 static int pl011_remove(struct amba_device *dev)
1811 {
1812 struct uart_amba_port *uap = amba_get_drvdata(dev);
1813 int i;
1814
1815 amba_set_drvdata(dev, NULL);
1816
1817 uart_remove_one_port(&amba_reg, &uap->port);
1818
1819 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1820 if (amba_ports[i] == uap)
1821 amba_ports[i] = NULL;
1822
1823 pl011_dma_remove(uap);
1824 iounmap(uap->port.membase);
1825 clk_put(uap->clk);
1826 kfree(uap);
1827 return 0;
1828 }
1829
1830 #ifdef CONFIG_PM
1831 static int pl011_suspend(struct amba_device *dev, pm_message_t state)
1832 {
1833 struct uart_amba_port *uap = amba_get_drvdata(dev);
1834
1835 if (!uap)
1836 return -EINVAL;
1837
1838 return uart_suspend_port(&amba_reg, &uap->port);
1839 }
1840
1841 static int pl011_resume(struct amba_device *dev)
1842 {
1843 struct uart_amba_port *uap = amba_get_drvdata(dev);
1844
1845 if (!uap)
1846 return -EINVAL;
1847
1848 return uart_resume_port(&amba_reg, &uap->port);
1849 }
1850 #endif
1851
1852 static struct amba_id pl011_ids[] = {
1853 {
1854 .id = 0x00041011,
1855 .mask = 0x000fffff,
1856 .data = &vendor_arm,
1857 },
1858 {
1859 .id = 0x00380802,
1860 .mask = 0x00ffffff,
1861 .data = &vendor_st,
1862 },
1863 { 0, 0 },
1864 };
1865
1866 static struct amba_driver pl011_driver = {
1867 .drv = {
1868 .name = "uart-pl011",
1869 },
1870 .id_table = pl011_ids,
1871 .probe = pl011_probe,
1872 .remove = pl011_remove,
1873 #ifdef CONFIG_PM
1874 .suspend = pl011_suspend,
1875 .resume = pl011_resume,
1876 #endif
1877 };
1878
1879 static int __init pl011_init(void)
1880 {
1881 int ret;
1882 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
1883
1884 ret = uart_register_driver(&amba_reg);
1885 if (ret == 0) {
1886 ret = amba_driver_register(&pl011_driver);
1887 if (ret)
1888 uart_unregister_driver(&amba_reg);
1889 }
1890 return ret;
1891 }
1892
1893 static void __exit pl011_exit(void)
1894 {
1895 amba_driver_unregister(&pl011_driver);
1896 uart_unregister_driver(&amba_reg);
1897 }
1898
1899 /*
1900 * While this can be a module, if builtin it's most likely the console
1901 * So let's leave module_exit but move module_init to an earlier place
1902 */
1903 arch_initcall(pl011_init);
1904 module_exit(pl011_exit);
1905
1906 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
1907 MODULE_DESCRIPTION("ARM AMBA serial port driver");
1908 MODULE_LICENSE("GPL");
Linux 2.6 ibm-acpi/thinkpad-acpi driver git tree