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uprobes: Teach handle_swbp() to rely on "is_swbp" rather than uprobes_srcu
[linux-2.6.git] / drivers / tty / serial / amba-pl011.c
blob4ad721fb84052a61c3452d12532bcc9d21c9a84a
1 /*
2 * Driver for AMBA serial ports
3 *
4 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
5 *
6 * Copyright 1999 ARM Limited
7 * Copyright (C) 2000 Deep Blue Solutions Ltd.
8 * Copyright (C) 2010 ST-Ericsson SA
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 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
23 *
24 * This is a generic driver for ARM AMBA-type serial ports. They
25 * have a lot of 16550-like features, but are not register compatible.
26 * Note that although they do have CTS, DCD and DSR inputs, they do
27 * not have an RI input, nor do they have DTR or RTS outputs. If
28 * required, these have to be supplied via some other means (eg, GPIO)
29 * and hooked into this driver.
30 */
31
32 #if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
33 #define SUPPORT_SYSRQ
34 #endif
35
36 #include <linux/module.h>
37 #include <linux/ioport.h>
38 #include <linux/init.h>
39 #include <linux/console.h>
40 #include <linux/sysrq.h>
41 #include <linux/device.h>
42 #include <linux/tty.h>
43 #include <linux/tty_flip.h>
44 #include <linux/serial_core.h>
45 #include <linux/serial.h>
46 #include <linux/amba/bus.h>
47 #include <linux/amba/serial.h>
48 #include <linux/clk.h>
49 #include <linux/slab.h>
50 #include <linux/dmaengine.h>
51 #include <linux/dma-mapping.h>
52 #include <linux/scatterlist.h>
53 #include <linux/delay.h>
54 #include <linux/types.h>
55 #include <linux/pinctrl/consumer.h>
56
57 #include <asm/io.h>
58 #include <asm/sizes.h>
59
60 #define UART_NR 14
61
62 #define SERIAL_AMBA_MAJOR 204
63 #define SERIAL_AMBA_MINOR 64
64 #define SERIAL_AMBA_NR UART_NR
65
66 #define AMBA_ISR_PASS_LIMIT 256
67
68 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
69 #define UART_DUMMY_DR_RX (1 << 16)
70
71 /* There is by now at least one vendor with differing details, so handle it */
72 struct vendor_data {
73 unsigned int ifls;
74 unsigned int fifosize;
75 unsigned int lcrh_tx;
76 unsigned int lcrh_rx;
77 bool oversampling;
78 bool interrupt_may_hang; /* vendor-specific */
79 bool dma_threshold;
80 bool cts_event_workaround;
81 };
82
83 static struct vendor_data vendor_arm = {
84 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
85 .fifosize = 16,
86 .lcrh_tx = UART011_LCRH,
87 .lcrh_rx = UART011_LCRH,
88 .oversampling = false,
89 .dma_threshold = false,
90 .cts_event_workaround = false,
91 };
92
93 static struct vendor_data vendor_st = {
94 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
95 .fifosize = 64,
96 .lcrh_tx = ST_UART011_LCRH_TX,
97 .lcrh_rx = ST_UART011_LCRH_RX,
98 .oversampling = true,
99 .interrupt_may_hang = true,
100 .dma_threshold = true,
101 .cts_event_workaround = true,
102 };
103
104 static struct uart_amba_port *amba_ports[UART_NR];
105
106 /* Deals with DMA transactions */
107
108 struct pl011_sgbuf {
109 struct scatterlist sg;
110 char *buf;
111 };
112
113 struct pl011_dmarx_data {
114 struct dma_chan *chan;
115 struct completion complete;
116 bool use_buf_b;
117 struct pl011_sgbuf sgbuf_a;
118 struct pl011_sgbuf sgbuf_b;
119 dma_cookie_t cookie;
120 bool running;
121 };
122
123 struct pl011_dmatx_data {
124 struct dma_chan *chan;
125 struct scatterlist sg;
126 char *buf;
127 bool queued;
128 };
129
130 /*
131 * We wrap our port structure around the generic uart_port.
132 */
133 struct uart_amba_port {
134 struct uart_port port;
135 struct clk *clk;
136 const struct vendor_data *vendor;
137 unsigned int dmacr; /* dma control reg */
138 unsigned int im; /* interrupt mask */
139 unsigned int old_status;
140 unsigned int fifosize; /* vendor-specific */
141 unsigned int lcrh_tx; /* vendor-specific */
142 unsigned int lcrh_rx; /* vendor-specific */
143 unsigned int old_cr; /* state during shutdown */
144 bool autorts;
145 char type[12];
146 bool interrupt_may_hang; /* vendor-specific */
147 #ifdef CONFIG_DMA_ENGINE
148 /* DMA stuff */
149 bool using_tx_dma;
150 bool using_rx_dma;
151 struct pl011_dmarx_data dmarx;
152 struct pl011_dmatx_data dmatx;
153 #endif
154 };
155
156 /*
157 * Reads up to 256 characters from the FIFO or until it's empty and
158 * inserts them into the TTY layer. Returns the number of characters
159 * read from the FIFO.
160 */
161 static int pl011_fifo_to_tty(struct uart_amba_port *uap)
162 {
163 u16 status, ch;
164 unsigned int flag, max_count = 256;
165 int fifotaken = 0;
166
167 while (max_count--) {
168 status = readw(uap->port.membase + UART01x_FR);
169 if (status & UART01x_FR_RXFE)
170 break;
171
172 /* Take chars from the FIFO and update status */
173 ch = readw(uap->port.membase + UART01x_DR) |
174 UART_DUMMY_DR_RX;
175 flag = TTY_NORMAL;
176 uap->port.icount.rx++;
177 fifotaken++;
178
179 if (unlikely(ch & UART_DR_ERROR)) {
180 if (ch & UART011_DR_BE) {
181 ch &= ~(UART011_DR_FE | UART011_DR_PE);
182 uap->port.icount.brk++;
183 if (uart_handle_break(&uap->port))
184 continue;
185 } else if (ch & UART011_DR_PE)
186 uap->port.icount.parity++;
187 else if (ch & UART011_DR_FE)
188 uap->port.icount.frame++;
189 if (ch & UART011_DR_OE)
190 uap->port.icount.overrun++;
191
192 ch &= uap->port.read_status_mask;
193
194 if (ch & UART011_DR_BE)
195 flag = TTY_BREAK;
196 else if (ch & UART011_DR_PE)
197 flag = TTY_PARITY;
198 else if (ch & UART011_DR_FE)
199 flag = TTY_FRAME;
200 }
201
202 if (uart_handle_sysrq_char(&uap->port, ch & 255))
203 continue;
204
205 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
206 }
207
208 return fifotaken;
209 }
210
211
212 /*
213 * All the DMA operation mode stuff goes inside this ifdef.
214 * This assumes that you have a generic DMA device interface,
215 * no custom DMA interfaces are supported.
216 */
217 #ifdef CONFIG_DMA_ENGINE
218
219 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE
220
221 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
222 enum dma_data_direction dir)
223 {
224 sg->buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
225 if (!sg->buf)
226 return -ENOMEM;
227
228 sg_init_one(&sg->sg, sg->buf, PL011_DMA_BUFFER_SIZE);
229
230 if (dma_map_sg(chan->device->dev, &sg->sg, 1, dir) != 1) {
231 kfree(sg->buf);
232 return -EINVAL;
233 }
234 return 0;
235 }
236
237 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
238 enum dma_data_direction dir)
239 {
240 if (sg->buf) {
241 dma_unmap_sg(chan->device->dev, &sg->sg, 1, dir);
242 kfree(sg->buf);
243 }
244 }
245
246 static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
247 {
248 /* DMA is the sole user of the platform data right now */
249 struct amba_pl011_data *plat = uap->port.dev->platform_data;
250 struct dma_slave_config tx_conf = {
251 .dst_addr = uap->port.mapbase + UART01x_DR,
252 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
253 .direction = DMA_MEM_TO_DEV,
254 .dst_maxburst = uap->fifosize >> 1,
255 .device_fc = false,
256 };
257 struct dma_chan *chan;
258 dma_cap_mask_t mask;
259
260 /* We need platform data */
261 if (!plat || !plat->dma_filter) {
262 dev_info(uap->port.dev, "no DMA platform data\n");
263 return;
264 }
265
266 /* Try to acquire a generic DMA engine slave TX channel */
267 dma_cap_zero(mask);
268 dma_cap_set(DMA_SLAVE, mask);
269
270 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param);
271 if (!chan) {
272 dev_err(uap->port.dev, "no TX DMA channel!\n");
273 return;
274 }
275
276 dmaengine_slave_config(chan, &tx_conf);
277 uap->dmatx.chan = chan;
278
279 dev_info(uap->port.dev, "DMA channel TX %s\n",
280 dma_chan_name(uap->dmatx.chan));
281
282 /* Optionally make use of an RX channel as well */
283 if (plat->dma_rx_param) {
284 struct dma_slave_config rx_conf = {
285 .src_addr = uap->port.mapbase + UART01x_DR,
286 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
287 .direction = DMA_DEV_TO_MEM,
288 .src_maxburst = uap->fifosize >> 1,
289 .device_fc = false,
290 };
291
292 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
293 if (!chan) {
294 dev_err(uap->port.dev, "no RX DMA channel!\n");
295 return;
296 }
297
298 dmaengine_slave_config(chan, &rx_conf);
299 uap->dmarx.chan = chan;
300
301 dev_info(uap->port.dev, "DMA channel RX %s\n",
302 dma_chan_name(uap->dmarx.chan));
303 }
304 }
305
306 #ifndef MODULE
307 /*
308 * Stack up the UARTs and let the above initcall be done at device
309 * initcall time, because the serial driver is called as an arch
310 * initcall, and at this time the DMA subsystem is not yet registered.
311 * At this point the driver will switch over to using DMA where desired.
312 */
313 struct dma_uap {
314 struct list_head node;
315 struct uart_amba_port *uap;
316 };
317
318 static LIST_HEAD(pl011_dma_uarts);
319
320 static int __init pl011_dma_initcall(void)
321 {
322 struct list_head *node, *tmp;
323
324 list_for_each_safe(node, tmp, &pl011_dma_uarts) {
325 struct dma_uap *dmau = list_entry(node, struct dma_uap, node);
326 pl011_dma_probe_initcall(dmau->uap);
327 list_del(node);
328 kfree(dmau);
329 }
330 return 0;
331 }
332
333 device_initcall(pl011_dma_initcall);
334
335 static void pl011_dma_probe(struct uart_amba_port *uap)
336 {
337 struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL);
338 if (dmau) {
339 dmau->uap = uap;
340 list_add_tail(&dmau->node, &pl011_dma_uarts);
341 }
342 }
343 #else
344 static void pl011_dma_probe(struct uart_amba_port *uap)
345 {
346 pl011_dma_probe_initcall(uap);
347 }
348 #endif
349
350 static void pl011_dma_remove(struct uart_amba_port *uap)
351 {
352 /* TODO: remove the initcall if it has not yet executed */
353 if (uap->dmatx.chan)
354 dma_release_channel(uap->dmatx.chan);
355 if (uap->dmarx.chan)
356 dma_release_channel(uap->dmarx.chan);
357 }
358
359 /* Forward declare this for the refill routine */
360 static int pl011_dma_tx_refill(struct uart_amba_port *uap);
361
362 /*
363 * The current DMA TX buffer has been sent.
364 * Try to queue up another DMA buffer.
365 */
366 static void pl011_dma_tx_callback(void *data)
367 {
368 struct uart_amba_port *uap = data;
369 struct pl011_dmatx_data *dmatx = &uap->dmatx;
370 unsigned long flags;
371 u16 dmacr;
372
373 spin_lock_irqsave(&uap->port.lock, flags);
374 if (uap->dmatx.queued)
375 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
376 DMA_TO_DEVICE);
377
378 dmacr = uap->dmacr;
379 uap->dmacr = dmacr & ~UART011_TXDMAE;
380 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
381
382 /*
383 * If TX DMA was disabled, it means that we've stopped the DMA for
384 * some reason (eg, XOFF received, or we want to send an X-char.)
385 *
386 * Note: we need to be careful here of a potential race between DMA
387 * and the rest of the driver - if the driver disables TX DMA while
388 * a TX buffer completing, we must update the tx queued status to
389 * get further refills (hence we check dmacr).
390 */
391 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
392 uart_circ_empty(&uap->port.state->xmit)) {
393 uap->dmatx.queued = false;
394 spin_unlock_irqrestore(&uap->port.lock, flags);
395 return;
396 }
397
398 if (pl011_dma_tx_refill(uap) <= 0) {
399 /*
400 * We didn't queue a DMA buffer for some reason, but we
401 * have data pending to be sent. Re-enable the TX IRQ.
402 */
403 uap->im |= UART011_TXIM;
404 writew(uap->im, uap->port.membase + UART011_IMSC);
405 }
406 spin_unlock_irqrestore(&uap->port.lock, flags);
407 }
408
409 /*
410 * Try to refill the TX DMA buffer.
411 * Locking: called with port lock held and IRQs disabled.
412 * Returns:
413 * 1 if we queued up a TX DMA buffer.
414 * 0 if we didn't want to handle this by DMA
415 * <0 on error
416 */
417 static int pl011_dma_tx_refill(struct uart_amba_port *uap)
418 {
419 struct pl011_dmatx_data *dmatx = &uap->dmatx;
420 struct dma_chan *chan = dmatx->chan;
421 struct dma_device *dma_dev = chan->device;
422 struct dma_async_tx_descriptor *desc;
423 struct circ_buf *xmit = &uap->port.state->xmit;
424 unsigned int count;
425
426 /*
427 * Try to avoid the overhead involved in using DMA if the
428 * transaction fits in the first half of the FIFO, by using
429 * the standard interrupt handling. This ensures that we
430 * issue a uart_write_wakeup() at the appropriate time.
431 */
432 count = uart_circ_chars_pending(xmit);
433 if (count < (uap->fifosize >> 1)) {
434 uap->dmatx.queued = false;
435 return 0;
436 }
437
438 /*
439 * Bodge: don't send the last character by DMA, as this
440 * will prevent XON from notifying us to restart DMA.
441 */
442 count -= 1;
443
444 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
445 if (count > PL011_DMA_BUFFER_SIZE)
446 count = PL011_DMA_BUFFER_SIZE;
447
448 if (xmit->tail < xmit->head)
449 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
450 else {
451 size_t first = UART_XMIT_SIZE - xmit->tail;
452 size_t second = xmit->head;
453
454 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
455 if (second)
456 memcpy(&dmatx->buf[first], &xmit->buf[0], second);
457 }
458
459 dmatx->sg.length = count;
460
461 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
462 uap->dmatx.queued = false;
463 dev_dbg(uap->port.dev, "unable to map TX DMA\n");
464 return -EBUSY;
465 }
466
467 desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
468 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
469 if (!desc) {
470 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
471 uap->dmatx.queued = false;
472 /*
473 * If DMA cannot be used right now, we complete this
474 * transaction via IRQ and let the TTY layer retry.
475 */
476 dev_dbg(uap->port.dev, "TX DMA busy\n");
477 return -EBUSY;
478 }
479
480 /* Some data to go along to the callback */
481 desc->callback = pl011_dma_tx_callback;
482 desc->callback_param = uap;
483
484 /* All errors should happen at prepare time */
485 dmaengine_submit(desc);
486
487 /* Fire the DMA transaction */
488 dma_dev->device_issue_pending(chan);
489
490 uap->dmacr |= UART011_TXDMAE;
491 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
492 uap->dmatx.queued = true;
493
494 /*
495 * Now we know that DMA will fire, so advance the ring buffer
496 * with the stuff we just dispatched.
497 */
498 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
499 uap->port.icount.tx += count;
500
501 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
502 uart_write_wakeup(&uap->port);
503
504 return 1;
505 }
506
507 /*
508 * We received a transmit interrupt without a pending X-char but with
509 * pending characters.
510 * Locking: called with port lock held and IRQs disabled.
511 * Returns:
512 * false if we want to use PIO to transmit
513 * true if we queued a DMA buffer
514 */
515 static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
516 {
517 if (!uap->using_tx_dma)
518 return false;
519
520 /*
521 * If we already have a TX buffer queued, but received a
522 * TX interrupt, it will be because we've just sent an X-char.
523 * Ensure the TX DMA is enabled and the TX IRQ is disabled.
524 */
525 if (uap->dmatx.queued) {
526 uap->dmacr |= UART011_TXDMAE;
527 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
528 uap->im &= ~UART011_TXIM;
529 writew(uap->im, uap->port.membase + UART011_IMSC);
530 return true;
531 }
532
533 /*
534 * We don't have a TX buffer queued, so try to queue one.
535 * If we successfully queued a buffer, mask the TX IRQ.
536 */
537 if (pl011_dma_tx_refill(uap) > 0) {
538 uap->im &= ~UART011_TXIM;
539 writew(uap->im, uap->port.membase + UART011_IMSC);
540 return true;
541 }
542 return false;
543 }
544
545 /*
546 * Stop the DMA transmit (eg, due to received XOFF).
547 * Locking: called with port lock held and IRQs disabled.
548 */
549 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
550 {
551 if (uap->dmatx.queued) {
552 uap->dmacr &= ~UART011_TXDMAE;
553 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
554 }
555 }
556
557 /*
558 * Try to start a DMA transmit, or in the case of an XON/OFF
559 * character queued for send, try to get that character out ASAP.
560 * Locking: called with port lock held and IRQs disabled.
561 * Returns:
562 * false if we want the TX IRQ to be enabled
563 * true if we have a buffer queued
564 */
565 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
566 {
567 u16 dmacr;
568
569 if (!uap->using_tx_dma)
570 return false;
571
572 if (!uap->port.x_char) {
573 /* no X-char, try to push chars out in DMA mode */
574 bool ret = true;
575
576 if (!uap->dmatx.queued) {
577 if (pl011_dma_tx_refill(uap) > 0) {
578 uap->im &= ~UART011_TXIM;
579 ret = true;
580 } else {
581 uap->im |= UART011_TXIM;
582 ret = false;
583 }
584 writew(uap->im, uap->port.membase + UART011_IMSC);
585 } else if (!(uap->dmacr & UART011_TXDMAE)) {
586 uap->dmacr |= UART011_TXDMAE;
587 writew(uap->dmacr,
588 uap->port.membase + UART011_DMACR);
589 }
590 return ret;
591 }
592
593 /*
594 * We have an X-char to send. Disable DMA to prevent it loading
595 * the TX fifo, and then see if we can stuff it into the FIFO.
596 */
597 dmacr = uap->dmacr;
598 uap->dmacr &= ~UART011_TXDMAE;
599 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
600
601 if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) {
602 /*
603 * No space in the FIFO, so enable the transmit interrupt
604 * so we know when there is space. Note that once we've
605 * loaded the character, we should just re-enable DMA.
606 */
607 return false;
608 }
609
610 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
611 uap->port.icount.tx++;
612 uap->port.x_char = 0;
613
614 /* Success - restore the DMA state */
615 uap->dmacr = dmacr;
616 writew(dmacr, uap->port.membase + UART011_DMACR);
617
618 return true;
619 }
620
621 /*
622 * Flush the transmit buffer.
623 * Locking: called with port lock held and IRQs disabled.
624 */
625 static void pl011_dma_flush_buffer(struct uart_port *port)
626 {
627 struct uart_amba_port *uap = (struct uart_amba_port *)port;
628
629 if (!uap->using_tx_dma)
630 return;
631
632 /* Avoid deadlock with the DMA engine callback */
633 spin_unlock(&uap->port.lock);
634 dmaengine_terminate_all(uap->dmatx.chan);
635 spin_lock(&uap->port.lock);
636 if (uap->dmatx.queued) {
637 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
638 DMA_TO_DEVICE);
639 uap->dmatx.queued = false;
640 uap->dmacr &= ~UART011_TXDMAE;
641 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
642 }
643 }
644
645 static void pl011_dma_rx_callback(void *data);
646
647 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
648 {
649 struct dma_chan *rxchan = uap->dmarx.chan;
650 struct pl011_dmarx_data *dmarx = &uap->dmarx;
651 struct dma_async_tx_descriptor *desc;
652 struct pl011_sgbuf *sgbuf;
653
654 if (!rxchan)
655 return -EIO;
656
657 /* Start the RX DMA job */
658 sgbuf = uap->dmarx.use_buf_b ?
659 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
660 desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
661 DMA_DEV_TO_MEM,
662 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
663 /*
664 * If the DMA engine is busy and cannot prepare a
665 * channel, no big deal, the driver will fall back
666 * to interrupt mode as a result of this error code.
667 */
668 if (!desc) {
669 uap->dmarx.running = false;
670 dmaengine_terminate_all(rxchan);
671 return -EBUSY;
672 }
673
674 /* Some data to go along to the callback */
675 desc->callback = pl011_dma_rx_callback;
676 desc->callback_param = uap;
677 dmarx->cookie = dmaengine_submit(desc);
678 dma_async_issue_pending(rxchan);
679
680 uap->dmacr |= UART011_RXDMAE;
681 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
682 uap->dmarx.running = true;
683
684 uap->im &= ~UART011_RXIM;
685 writew(uap->im, uap->port.membase + UART011_IMSC);
686
687 return 0;
688 }
689
690 /*
691 * This is called when either the DMA job is complete, or
692 * the FIFO timeout interrupt occurred. This must be called
693 * with the port spinlock uap->port.lock held.
694 */
695 static void pl011_dma_rx_chars(struct uart_amba_port *uap,
696 u32 pending, bool use_buf_b,
697 bool readfifo)
698 {
699 struct tty_struct *tty = uap->port.state->port.tty;
700 struct pl011_sgbuf *sgbuf = use_buf_b ?
701 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
702 struct device *dev = uap->dmarx.chan->device->dev;
703 int dma_count = 0;
704 u32 fifotaken = 0; /* only used for vdbg() */
705
706 /* Pick everything from the DMA first */
707 if (pending) {
708 /* Sync in buffer */
709 dma_sync_sg_for_cpu(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
710
711 /*
712 * First take all chars in the DMA pipe, then look in the FIFO.
713 * Note that tty_insert_flip_buf() tries to take as many chars
714 * as it can.
715 */
716 dma_count = tty_insert_flip_string(uap->port.state->port.tty,
717 sgbuf->buf, pending);
718
719 /* Return buffer to device */
720 dma_sync_sg_for_device(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
721
722 uap->port.icount.rx += dma_count;
723 if (dma_count < pending)
724 dev_warn(uap->port.dev,
725 "couldn't insert all characters (TTY is full?)\n");
726 }
727
728 /*
729 * Only continue with trying to read the FIFO if all DMA chars have
730 * been taken first.
731 */
732 if (dma_count == pending && readfifo) {
733 /* Clear any error flags */
734 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
735 uap->port.membase + UART011_ICR);
736
737 /*
738 * If we read all the DMA'd characters, and we had an
739 * incomplete buffer, that could be due to an rx error, or
740 * maybe we just timed out. Read any pending chars and check
741 * the error status.
742 *
743 * Error conditions will only occur in the FIFO, these will
744 * trigger an immediate interrupt and stop the DMA job, so we
745 * will always find the error in the FIFO, never in the DMA
746 * buffer.
747 */
748 fifotaken = pl011_fifo_to_tty(uap);
749 }
750
751 spin_unlock(&uap->port.lock);
752 dev_vdbg(uap->port.dev,
753 "Took %d chars from DMA buffer and %d chars from the FIFO\n",
754 dma_count, fifotaken);
755 tty_flip_buffer_push(tty);
756 spin_lock(&uap->port.lock);
757 }
758
759 static void pl011_dma_rx_irq(struct uart_amba_port *uap)
760 {
761 struct pl011_dmarx_data *dmarx = &uap->dmarx;
762 struct dma_chan *rxchan = dmarx->chan;
763 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
764 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
765 size_t pending;
766 struct dma_tx_state state;
767 enum dma_status dmastat;
768
769 /*
770 * Pause the transfer so we can trust the current counter,
771 * do this before we pause the PL011 block, else we may
772 * overflow the FIFO.
773 */
774 if (dmaengine_pause(rxchan))
775 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
776 dmastat = rxchan->device->device_tx_status(rxchan,
777 dmarx->cookie, &state);
778 if (dmastat != DMA_PAUSED)
779 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
780
781 /* Disable RX DMA - incoming data will wait in the FIFO */
782 uap->dmacr &= ~UART011_RXDMAE;
783 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
784 uap->dmarx.running = false;
785
786 pending = sgbuf->sg.length - state.residue;
787 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
788 /* Then we terminate the transfer - we now know our residue */
789 dmaengine_terminate_all(rxchan);
790
791 /*
792 * This will take the chars we have so far and insert
793 * into the framework.
794 */
795 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
796
797 /* Switch buffer & re-trigger DMA job */
798 dmarx->use_buf_b = !dmarx->use_buf_b;
799 if (pl011_dma_rx_trigger_dma(uap)) {
800 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
801 "fall back to interrupt mode\n");
802 uap->im |= UART011_RXIM;
803 writew(uap->im, uap->port.membase + UART011_IMSC);
804 }
805 }
806
807 static void pl011_dma_rx_callback(void *data)
808 {
809 struct uart_amba_port *uap = data;
810 struct pl011_dmarx_data *dmarx = &uap->dmarx;
811 struct dma_chan *rxchan = dmarx->chan;
812 bool lastbuf = dmarx->use_buf_b;
813 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
814 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
815 size_t pending;
816 struct dma_tx_state state;
817 int ret;
818
819 /*
820 * This completion interrupt occurs typically when the
821 * RX buffer is totally stuffed but no timeout has yet
822 * occurred. When that happens, we just want the RX
823 * routine to flush out the secondary DMA buffer while
824 * we immediately trigger the next DMA job.
825 */
826 spin_lock_irq(&uap->port.lock);
827 /*
828 * Rx data can be taken by the UART interrupts during
829 * the DMA irq handler. So we check the residue here.
830 */
831 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
832 pending = sgbuf->sg.length - state.residue;
833 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
834 /* Then we terminate the transfer - we now know our residue */
835 dmaengine_terminate_all(rxchan);
836
837 uap->dmarx.running = false;
838 dmarx->use_buf_b = !lastbuf;
839 ret = pl011_dma_rx_trigger_dma(uap);
840
841 pl011_dma_rx_chars(uap, pending, lastbuf, false);
842 spin_unlock_irq(&uap->port.lock);
843 /*
844 * Do this check after we picked the DMA chars so we don't
845 * get some IRQ immediately from RX.
846 */
847 if (ret) {
848 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
849 "fall back to interrupt mode\n");
850 uap->im |= UART011_RXIM;
851 writew(uap->im, uap->port.membase + UART011_IMSC);
852 }
853 }
854
855 /*
856 * Stop accepting received characters, when we're shutting down or
857 * suspending this port.
858 * Locking: called with port lock held and IRQs disabled.
859 */
860 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
861 {
862 /* FIXME. Just disable the DMA enable */
863 uap->dmacr &= ~UART011_RXDMAE;
864 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
865 }
866
867 static void pl011_dma_startup(struct uart_amba_port *uap)
868 {
869 int ret;
870
871 if (!uap->dmatx.chan)
872 return;
873
874 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
875 if (!uap->dmatx.buf) {
876 dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
877 uap->port.fifosize = uap->fifosize;
878 return;
879 }
880
881 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
882
883 /* The DMA buffer is now the FIFO the TTY subsystem can use */
884 uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
885 uap->using_tx_dma = true;
886
887 if (!uap->dmarx.chan)
888 goto skip_rx;
889
890 /* Allocate and map DMA RX buffers */
891 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
892 DMA_FROM_DEVICE);
893 if (ret) {
894 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
895 "RX buffer A", ret);
896 goto skip_rx;
897 }
898
899 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
900 DMA_FROM_DEVICE);
901 if (ret) {
902 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
903 "RX buffer B", ret);
904 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
905 DMA_FROM_DEVICE);
906 goto skip_rx;
907 }
908
909 uap->using_rx_dma = true;
910
911 skip_rx:
912 /* Turn on DMA error (RX/TX will be enabled on demand) */
913 uap->dmacr |= UART011_DMAONERR;
914 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
915
916 /*
917 * ST Micro variants has some specific dma burst threshold
918 * compensation. Set this to 16 bytes, so burst will only
919 * be issued above/below 16 bytes.
920 */
921 if (uap->vendor->dma_threshold)
922 writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
923 uap->port.membase + ST_UART011_DMAWM);
924
925 if (uap->using_rx_dma) {
926 if (pl011_dma_rx_trigger_dma(uap))
927 dev_dbg(uap->port.dev, "could not trigger initial "
928 "RX DMA job, fall back to interrupt mode\n");
929 }
930 }
931
932 static void pl011_dma_shutdown(struct uart_amba_port *uap)
933 {
934 if (!(uap->using_tx_dma || uap->using_rx_dma))
935 return;
936
937 /* Disable RX and TX DMA */
938 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
939 barrier();
940
941 spin_lock_irq(&uap->port.lock);
942 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
943 writew(uap->dmacr, uap->port.membase + UART011_DMACR);
944 spin_unlock_irq(&uap->port.lock);
945
946 if (uap->using_tx_dma) {
947 /* In theory, this should already be done by pl011_dma_flush_buffer */
948 dmaengine_terminate_all(uap->dmatx.chan);
949 if (uap->dmatx.queued) {
950 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
951 DMA_TO_DEVICE);
952 uap->dmatx.queued = false;
953 }
954
955 kfree(uap->dmatx.buf);
956 uap->using_tx_dma = false;
957 }
958
959 if (uap->using_rx_dma) {
960 dmaengine_terminate_all(uap->dmarx.chan);
961 /* Clean up the RX DMA */
962 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
963 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
964 uap->using_rx_dma = false;
965 }
966 }
967
968 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
969 {
970 return uap->using_rx_dma;
971 }
972
973 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
974 {
975 return uap->using_rx_dma && uap->dmarx.running;
976 }
977
978
979 #else
980 /* Blank functions if the DMA engine is not available */
981 static inline void pl011_dma_probe(struct uart_amba_port *uap)
982 {
983 }
984
985 static inline void pl011_dma_remove(struct uart_amba_port *uap)
986 {
987 }
988
989 static inline void pl011_dma_startup(struct uart_amba_port *uap)
990 {
991 }
992
993 static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
994 {
995 }
996
997 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
998 {
999 return false;
1000 }
1001
1002 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
1003 {
1004 }
1005
1006 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
1007 {
1008 return false;
1009 }
1010
1011 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
1012 {
1013 }
1014
1015 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1016 {
1017 }
1018
1019 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
1020 {
1021 return -EIO;
1022 }
1023
1024 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1025 {
1026 return false;
1027 }
1028
1029 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1030 {
1031 return false;
1032 }
1033
1034 #define pl011_dma_flush_buffer NULL
1035 #endif
1036
1037 static void pl011_stop_tx(struct uart_port *port)
1038 {
1039 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1040
1041 uap->im &= ~UART011_TXIM;
1042 writew(uap->im, uap->port.membase + UART011_IMSC);
1043 pl011_dma_tx_stop(uap);
1044 }
1045
1046 static void pl011_start_tx(struct uart_port *port)
1047 {
1048 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1049
1050 if (!pl011_dma_tx_start(uap)) {
1051 uap->im |= UART011_TXIM;
1052 writew(uap->im, uap->port.membase + UART011_IMSC);
1053 }
1054 }
1055
1056 static void pl011_stop_rx(struct uart_port *port)
1057 {
1058 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1059
1060 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
1061 UART011_PEIM|UART011_BEIM|UART011_OEIM);
1062 writew(uap->im, uap->port.membase + UART011_IMSC);
1063
1064 pl011_dma_rx_stop(uap);
1065 }
1066
1067 static void pl011_enable_ms(struct uart_port *port)
1068 {
1069 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1070
1071 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
1072 writew(uap->im, uap->port.membase + UART011_IMSC);
1073 }
1074
1075 static void pl011_rx_chars(struct uart_amba_port *uap)
1076 {
1077 struct tty_struct *tty = uap->port.state->port.tty;
1078
1079 pl011_fifo_to_tty(uap);
1080
1081 spin_unlock(&uap->port.lock);
1082 tty_flip_buffer_push(tty);
1083 /*
1084 * If we were temporarily out of DMA mode for a while,
1085 * attempt to switch back to DMA mode again.
1086 */
1087 if (pl011_dma_rx_available(uap)) {
1088 if (pl011_dma_rx_trigger_dma(uap)) {
1089 dev_dbg(uap->port.dev, "could not trigger RX DMA job "
1090 "fall back to interrupt mode again\n");
1091 uap->im |= UART011_RXIM;
1092 } else
1093 uap->im &= ~UART011_RXIM;
1094 writew(uap->im, uap->port.membase + UART011_IMSC);
1095 }
1096 spin_lock(&uap->port.lock);
1097 }
1098
1099 static void pl011_tx_chars(struct uart_amba_port *uap)
1100 {
1101 struct circ_buf *xmit = &uap->port.state->xmit;
1102 int count;
1103
1104 if (uap->port.x_char) {
1105 writew(uap->port.x_char, uap->port.membase + UART01x_DR);
1106 uap->port.icount.tx++;
1107 uap->port.x_char = 0;
1108 return;
1109 }
1110 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
1111 pl011_stop_tx(&uap->port);
1112 return;
1113 }
1114
1115 /* If we are using DMA mode, try to send some characters. */
1116 if (pl011_dma_tx_irq(uap))
1117 return;
1118
1119 count = uap->fifosize >> 1;
1120 do {
1121 writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
1122 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1123 uap->port.icount.tx++;
1124 if (uart_circ_empty(xmit))
1125 break;
1126 } while (--count > 0);
1127
1128 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1129 uart_write_wakeup(&uap->port);
1130
1131 if (uart_circ_empty(xmit))
1132 pl011_stop_tx(&uap->port);
1133 }
1134
1135 static void pl011_modem_status(struct uart_amba_port *uap)
1136 {
1137 unsigned int status, delta;
1138
1139 status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1140
1141 delta = status ^ uap->old_status;
1142 uap->old_status = status;
1143
1144 if (!delta)
1145 return;
1146
1147 if (delta & UART01x_FR_DCD)
1148 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
1149
1150 if (delta & UART01x_FR_DSR)
1151 uap->port.icount.dsr++;
1152
1153 if (delta & UART01x_FR_CTS)
1154 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
1155
1156 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
1157 }
1158
1159 static irqreturn_t pl011_int(int irq, void *dev_id)
1160 {
1161 struct uart_amba_port *uap = dev_id;
1162 unsigned long flags;
1163 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
1164 int handled = 0;
1165 unsigned int dummy_read;
1166
1167 spin_lock_irqsave(&uap->port.lock, flags);
1168
1169 status = readw(uap->port.membase + UART011_MIS);
1170 if (status) {
1171 do {
1172 if (uap->vendor->cts_event_workaround) {
1173 /* workaround to make sure that all bits are unlocked.. */
1174 writew(0x00, uap->port.membase + UART011_ICR);
1175
1176 /*
1177 * WA: introduce 26ns(1 uart clk) delay before W1C;
1178 * single apb access will incur 2 pclk(133.12Mhz) delay,
1179 * so add 2 dummy reads
1180 */
1181 dummy_read = readw(uap->port.membase + UART011_ICR);
1182 dummy_read = readw(uap->port.membase + UART011_ICR);
1183 }
1184
1185 writew(status & ~(UART011_TXIS|UART011_RTIS|
1186 UART011_RXIS),
1187 uap->port.membase + UART011_ICR);
1188
1189 if (status & (UART011_RTIS|UART011_RXIS)) {
1190 if (pl011_dma_rx_running(uap))
1191 pl011_dma_rx_irq(uap);
1192 else
1193 pl011_rx_chars(uap);
1194 }
1195 if (status & (UART011_DSRMIS|UART011_DCDMIS|
1196 UART011_CTSMIS|UART011_RIMIS))
1197 pl011_modem_status(uap);
1198 if (status & UART011_TXIS)
1199 pl011_tx_chars(uap);
1200
1201 if (pass_counter-- == 0)
1202 break;
1203
1204 status = readw(uap->port.membase + UART011_MIS);
1205 } while (status != 0);
1206 handled = 1;
1207 }
1208
1209 spin_unlock_irqrestore(&uap->port.lock, flags);
1210
1211 return IRQ_RETVAL(handled);
1212 }
1213
1214 static unsigned int pl01x_tx_empty(struct uart_port *port)
1215 {
1216 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1217 unsigned int status = readw(uap->port.membase + UART01x_FR);
1218 return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
1219 }
1220
1221 static unsigned int pl01x_get_mctrl(struct uart_port *port)
1222 {
1223 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1224 unsigned int result = 0;
1225 unsigned int status = readw(uap->port.membase + UART01x_FR);
1226
1227 #define TIOCMBIT(uartbit, tiocmbit) \
1228 if (status & uartbit) \
1229 result |= tiocmbit
1230
1231 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
1232 TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
1233 TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
1234 TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
1235 #undef TIOCMBIT
1236 return result;
1237 }
1238
1239 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
1240 {
1241 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1242 unsigned int cr;
1243
1244 cr = readw(uap->port.membase + UART011_CR);
1245
1246 #define TIOCMBIT(tiocmbit, uartbit) \
1247 if (mctrl & tiocmbit) \
1248 cr |= uartbit; \
1249 else \
1250 cr &= ~uartbit
1251
1252 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
1253 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
1254 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
1255 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
1256 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
1257
1258 if (uap->autorts) {
1259 /* We need to disable auto-RTS if we want to turn RTS off */
1260 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
1261 }
1262 #undef TIOCMBIT
1263
1264 writew(cr, uap->port.membase + UART011_CR);
1265 }
1266
1267 static void pl011_break_ctl(struct uart_port *port, int break_state)
1268 {
1269 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1270 unsigned long flags;
1271 unsigned int lcr_h;
1272
1273 spin_lock_irqsave(&uap->port.lock, flags);
1274 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1275 if (break_state == -1)
1276 lcr_h |= UART01x_LCRH_BRK;
1277 else
1278 lcr_h &= ~UART01x_LCRH_BRK;
1279 writew(lcr_h, uap->port.membase + uap->lcrh_tx);
1280 spin_unlock_irqrestore(&uap->port.lock, flags);
1281 }
1282
1283 #ifdef CONFIG_CONSOLE_POLL
1284 static int pl010_get_poll_char(struct uart_port *port)
1285 {
1286 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1287 unsigned int status;
1288
1289 status = readw(uap->port.membase + UART01x_FR);
1290 if (status & UART01x_FR_RXFE)
1291 return NO_POLL_CHAR;
1292
1293 return readw(uap->port.membase + UART01x_DR);
1294 }
1295
1296 static void pl010_put_poll_char(struct uart_port *port,
1297 unsigned char ch)
1298 {
1299 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1300
1301 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1302 barrier();
1303
1304 writew(ch, uap->port.membase + UART01x_DR);
1305 }
1306
1307 #endif /* CONFIG_CONSOLE_POLL */
1308
1309 static int pl011_startup(struct uart_port *port)
1310 {
1311 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1312 unsigned int cr;
1313 int retval;
1314
1315 retval = clk_prepare(uap->clk);
1316 if (retval)
1317 goto out;
1318
1319 /*
1320 * Try to enable the clock producer.
1321 */
1322 retval = clk_enable(uap->clk);
1323 if (retval)
1324 goto clk_unprep;
1325
1326 uap->port.uartclk = clk_get_rate(uap->clk);
1327
1328 /* Clear pending error and receive interrupts */
1329 writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS |
1330 UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR);
1331
1332 /*
1333 * Allocate the IRQ
1334 */
1335 retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
1336 if (retval)
1337 goto clk_dis;
1338
1339 writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
1340
1341 /*
1342 * Provoke TX FIFO interrupt into asserting.
1343 */
1344 cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE;
1345 writew(cr, uap->port.membase + UART011_CR);
1346 writew(0, uap->port.membase + UART011_FBRD);
1347 writew(1, uap->port.membase + UART011_IBRD);
1348 writew(0, uap->port.membase + uap->lcrh_rx);
1349 if (uap->lcrh_tx != uap->lcrh_rx) {
1350 int i;
1351 /*
1352 * Wait 10 PCLKs before writing LCRH_TX register,
1353 * to get this delay write read only register 10 times
1354 */
1355 for (i = 0; i < 10; ++i)
1356 writew(0xff, uap->port.membase + UART011_MIS);
1357 writew(0, uap->port.membase + uap->lcrh_tx);
1358 }
1359 writew(0, uap->port.membase + UART01x_DR);
1360 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
1361 barrier();
1362
1363 /* restore RTS and DTR */
1364 cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
1365 cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
1366 writew(cr, uap->port.membase + UART011_CR);
1367
1368 /*
1369 * initialise the old status of the modem signals
1370 */
1371 uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
1372
1373 /* Startup DMA */
1374 pl011_dma_startup(uap);
1375
1376 /*
1377 * Finally, enable interrupts, only timeouts when using DMA
1378 * if initial RX DMA job failed, start in interrupt mode
1379 * as well.
1380 */
1381 spin_lock_irq(&uap->port.lock);
1382 /* Clear out any spuriously appearing RX interrupts */
1383 writew(UART011_RTIS | UART011_RXIS,
1384 uap->port.membase + UART011_ICR);
1385 uap->im = UART011_RTIM;
1386 if (!pl011_dma_rx_running(uap))
1387 uap->im |= UART011_RXIM;
1388 writew(uap->im, uap->port.membase + UART011_IMSC);
1389 spin_unlock_irq(&uap->port.lock);
1390
1391 if (uap->port.dev->platform_data) {
1392 struct amba_pl011_data *plat;
1393
1394 plat = uap->port.dev->platform_data;
1395 if (plat->init)
1396 plat->init();
1397 }
1398
1399 return 0;
1400
1401 clk_dis:
1402 clk_disable(uap->clk);
1403 clk_unprep:
1404 clk_unprepare(uap->clk);
1405 out:
1406 return retval;
1407 }
1408
1409 static void pl011_shutdown_channel(struct uart_amba_port *uap,
1410 unsigned int lcrh)
1411 {
1412 unsigned long val;
1413
1414 val = readw(uap->port.membase + lcrh);
1415 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
1416 writew(val, uap->port.membase + lcrh);
1417 }
1418
1419 static void pl011_shutdown(struct uart_port *port)
1420 {
1421 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1422 unsigned int cr;
1423
1424 /*
1425 * disable all interrupts
1426 */
1427 spin_lock_irq(&uap->port.lock);
1428 uap->im = 0;
1429 writew(uap->im, uap->port.membase + UART011_IMSC);
1430 writew(0xffff, uap->port.membase + UART011_ICR);
1431 spin_unlock_irq(&uap->port.lock);
1432
1433 pl011_dma_shutdown(uap);
1434
1435 /*
1436 * Free the interrupt
1437 */
1438 free_irq(uap->port.irq, uap);
1439
1440 /*
1441 * disable the port
1442 * disable the port. It should not disable RTS and DTR.
1443 * Also RTS and DTR state should be preserved to restore
1444 * it during startup().
1445 */
1446 uap->autorts = false;
1447 cr = readw(uap->port.membase + UART011_CR);
1448 uap->old_cr = cr;
1449 cr &= UART011_CR_RTS | UART011_CR_DTR;
1450 cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1451 writew(cr, uap->port.membase + UART011_CR);
1452
1453 /*
1454 * disable break condition and fifos
1455 */
1456 pl011_shutdown_channel(uap, uap->lcrh_rx);
1457 if (uap->lcrh_rx != uap->lcrh_tx)
1458 pl011_shutdown_channel(uap, uap->lcrh_tx);
1459
1460 /*
1461 * Shut down the clock producer
1462 */
1463 clk_disable(uap->clk);
1464 clk_unprepare(uap->clk);
1465
1466 if (uap->port.dev->platform_data) {
1467 struct amba_pl011_data *plat;
1468
1469 plat = uap->port.dev->platform_data;
1470 if (plat->exit)
1471 plat->exit();
1472 }
1473
1474 }
1475
1476 static void
1477 pl011_set_termios(struct uart_port *port, struct ktermios *termios,
1478 struct ktermios *old)
1479 {
1480 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1481 unsigned int lcr_h, old_cr;
1482 unsigned long flags;
1483 unsigned int baud, quot, clkdiv;
1484
1485 if (uap->vendor->oversampling)
1486 clkdiv = 8;
1487 else
1488 clkdiv = 16;
1489
1490 /*
1491 * Ask the core to calculate the divisor for us.
1492 */
1493 baud = uart_get_baud_rate(port, termios, old, 0,
1494 port->uartclk / clkdiv);
1495
1496 if (baud > port->uartclk/16)
1497 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
1498 else
1499 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
1500
1501 switch (termios->c_cflag & CSIZE) {
1502 case CS5:
1503 lcr_h = UART01x_LCRH_WLEN_5;
1504 break;
1505 case CS6:
1506 lcr_h = UART01x_LCRH_WLEN_6;
1507 break;
1508 case CS7:
1509 lcr_h = UART01x_LCRH_WLEN_7;
1510 break;
1511 default: // CS8
1512 lcr_h = UART01x_LCRH_WLEN_8;
1513 break;
1514 }
1515 if (termios->c_cflag & CSTOPB)
1516 lcr_h |= UART01x_LCRH_STP2;
1517 if (termios->c_cflag & PARENB) {
1518 lcr_h |= UART01x_LCRH_PEN;
1519 if (!(termios->c_cflag & PARODD))
1520 lcr_h |= UART01x_LCRH_EPS;
1521 }
1522 if (uap->fifosize > 1)
1523 lcr_h |= UART01x_LCRH_FEN;
1524
1525 spin_lock_irqsave(&port->lock, flags);
1526
1527 /*
1528 * Update the per-port timeout.
1529 */
1530 uart_update_timeout(port, termios->c_cflag, baud);
1531
1532 port->read_status_mask = UART011_DR_OE | 255;
1533 if (termios->c_iflag & INPCK)
1534 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
1535 if (termios->c_iflag & (BRKINT | PARMRK))
1536 port->read_status_mask |= UART011_DR_BE;
1537
1538 /*
1539 * Characters to ignore
1540 */
1541 port->ignore_status_mask = 0;
1542 if (termios->c_iflag & IGNPAR)
1543 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
1544 if (termios->c_iflag & IGNBRK) {
1545 port->ignore_status_mask |= UART011_DR_BE;
1546 /*
1547 * If we're ignoring parity and break indicators,
1548 * ignore overruns too (for real raw support).
1549 */
1550 if (termios->c_iflag & IGNPAR)
1551 port->ignore_status_mask |= UART011_DR_OE;
1552 }
1553
1554 /*
1555 * Ignore all characters if CREAD is not set.
1556 */
1557 if ((termios->c_cflag & CREAD) == 0)
1558 port->ignore_status_mask |= UART_DUMMY_DR_RX;
1559
1560 if (UART_ENABLE_MS(port, termios->c_cflag))
1561 pl011_enable_ms(port);
1562
1563 /* first, disable everything */
1564 old_cr = readw(port->membase + UART011_CR);
1565 writew(0, port->membase + UART011_CR);
1566
1567 if (termios->c_cflag & CRTSCTS) {
1568 if (old_cr & UART011_CR_RTS)
1569 old_cr |= UART011_CR_RTSEN;
1570
1571 old_cr |= UART011_CR_CTSEN;
1572 uap->autorts = true;
1573 } else {
1574 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
1575 uap->autorts = false;
1576 }
1577
1578 if (uap->vendor->oversampling) {
1579 if (baud > port->uartclk / 16)
1580 old_cr |= ST_UART011_CR_OVSFACT;
1581 else
1582 old_cr &= ~ST_UART011_CR_OVSFACT;
1583 }
1584
1585 /* Set baud rate */
1586 writew(quot & 0x3f, port->membase + UART011_FBRD);
1587 writew(quot >> 6, port->membase + UART011_IBRD);
1588
1589 /*
1590 * ----------v----------v----------v----------v-----
1591 * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
1592 * ----------^----------^----------^----------^-----
1593 */
1594 writew(lcr_h, port->membase + uap->lcrh_rx);
1595 if (uap->lcrh_rx != uap->lcrh_tx) {
1596 int i;
1597 /*
1598 * Wait 10 PCLKs before writing LCRH_TX register,
1599 * to get this delay write read only register 10 times
1600 */
1601 for (i = 0; i < 10; ++i)
1602 writew(0xff, uap->port.membase + UART011_MIS);
1603 writew(lcr_h, port->membase + uap->lcrh_tx);
1604 }
1605 writew(old_cr, port->membase + UART011_CR);
1606
1607 spin_unlock_irqrestore(&port->lock, flags);
1608 }
1609
1610 static const char *pl011_type(struct uart_port *port)
1611 {
1612 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1613 return uap->port.type == PORT_AMBA ? uap->type : NULL;
1614 }
1615
1616 /*
1617 * Release the memory region(s) being used by 'port'
1618 */
1619 static void pl010_release_port(struct uart_port *port)
1620 {
1621 release_mem_region(port->mapbase, SZ_4K);
1622 }
1623
1624 /*
1625 * Request the memory region(s) being used by 'port'
1626 */
1627 static int pl010_request_port(struct uart_port *port)
1628 {
1629 return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
1630 != NULL ? 0 : -EBUSY;
1631 }
1632
1633 /*
1634 * Configure/autoconfigure the port.
1635 */
1636 static void pl010_config_port(struct uart_port *port, int flags)
1637 {
1638 if (flags & UART_CONFIG_TYPE) {
1639 port->type = PORT_AMBA;
1640 pl010_request_port(port);
1641 }
1642 }
1643
1644 /*
1645 * verify the new serial_struct (for TIOCSSERIAL).
1646 */
1647 static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
1648 {
1649 int ret = 0;
1650 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
1651 ret = -EINVAL;
1652 if (ser->irq < 0 || ser->irq >= nr_irqs)
1653 ret = -EINVAL;
1654 if (ser->baud_base < 9600)
1655 ret = -EINVAL;
1656 return ret;
1657 }
1658
1659 static struct uart_ops amba_pl011_pops = {
1660 .tx_empty = pl01x_tx_empty,
1661 .set_mctrl = pl011_set_mctrl,
1662 .get_mctrl = pl01x_get_mctrl,
1663 .stop_tx = pl011_stop_tx,
1664 .start_tx = pl011_start_tx,
1665 .stop_rx = pl011_stop_rx,
1666 .enable_ms = pl011_enable_ms,
1667 .break_ctl = pl011_break_ctl,
1668 .startup = pl011_startup,
1669 .shutdown = pl011_shutdown,
1670 .flush_buffer = pl011_dma_flush_buffer,
1671 .set_termios = pl011_set_termios,
1672 .type = pl011_type,
1673 .release_port = pl010_release_port,
1674 .request_port = pl010_request_port,
1675 .config_port = pl010_config_port,
1676 .verify_port = pl010_verify_port,
1677 #ifdef CONFIG_CONSOLE_POLL
1678 .poll_get_char = pl010_get_poll_char,
1679 .poll_put_char = pl010_put_poll_char,
1680 #endif
1681 };
1682
1683 static struct uart_amba_port *amba_ports[UART_NR];
1684
1685 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
1686
1687 static void pl011_console_putchar(struct uart_port *port, int ch)
1688 {
1689 struct uart_amba_port *uap = (struct uart_amba_port *)port;
1690
1691 while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
1692 barrier();
1693 writew(ch, uap->port.membase + UART01x_DR);
1694 }
1695
1696 static void
1697 pl011_console_write(struct console *co, const char *s, unsigned int count)
1698 {
1699 struct uart_amba_port *uap = amba_ports[co->index];
1700 unsigned int status, old_cr, new_cr;
1701 unsigned long flags;
1702 int locked = 1;
1703
1704 clk_enable(uap->clk);
1705
1706 local_irq_save(flags);
1707 if (uap->port.sysrq)
1708 locked = 0;
1709 else if (oops_in_progress)
1710 locked = spin_trylock(&uap->port.lock);
1711 else
1712 spin_lock(&uap->port.lock);
1713
1714 /*
1715 * First save the CR then disable the interrupts
1716 */
1717 old_cr = readw(uap->port.membase + UART011_CR);
1718 new_cr = old_cr & ~UART011_CR_CTSEN;
1719 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1720 writew(new_cr, uap->port.membase + UART011_CR);
1721
1722 uart_console_write(&uap->port, s, count, pl011_console_putchar);
1723
1724 /*
1725 * Finally, wait for transmitter to become empty
1726 * and restore the TCR
1727 */
1728 do {
1729 status = readw(uap->port.membase + UART01x_FR);
1730 } while (status & UART01x_FR_BUSY);
1731 writew(old_cr, uap->port.membase + UART011_CR);
1732
1733 if (locked)
1734 spin_unlock(&uap->port.lock);
1735 local_irq_restore(flags);
1736
1737 clk_disable(uap->clk);
1738 }
1739
1740 static void __init
1741 pl011_console_get_options(struct uart_amba_port *uap, int *baud,
1742 int *parity, int *bits)
1743 {
1744 if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
1745 unsigned int lcr_h, ibrd, fbrd;
1746
1747 lcr_h = readw(uap->port.membase + uap->lcrh_tx);
1748
1749 *parity = 'n';
1750 if (lcr_h & UART01x_LCRH_PEN) {
1751 if (lcr_h & UART01x_LCRH_EPS)
1752 *parity = 'e';
1753 else
1754 *parity = 'o';
1755 }
1756
1757 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
1758 *bits = 7;
1759 else
1760 *bits = 8;
1761
1762 ibrd = readw(uap->port.membase + UART011_IBRD);
1763 fbrd = readw(uap->port.membase + UART011_FBRD);
1764
1765 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
1766
1767 if (uap->vendor->oversampling) {
1768 if (readw(uap->port.membase + UART011_CR)
1769 & ST_UART011_CR_OVSFACT)
1770 *baud *= 2;
1771 }
1772 }
1773 }
1774
1775 static int __init pl011_console_setup(struct console *co, char *options)
1776 {
1777 struct uart_amba_port *uap;
1778 int baud = 38400;
1779 int bits = 8;
1780 int parity = 'n';
1781 int flow = 'n';
1782 int ret;
1783
1784 /*
1785 * Check whether an invalid uart number has been specified, and
1786 * if so, search for the first available port that does have
1787 * console support.
1788 */
1789 if (co->index >= UART_NR)
1790 co->index = 0;
1791 uap = amba_ports[co->index];
1792 if (!uap)
1793 return -ENODEV;
1794
1795 ret = clk_prepare(uap->clk);
1796 if (ret)
1797 return ret;
1798
1799 if (uap->port.dev->platform_data) {
1800 struct amba_pl011_data *plat;
1801
1802 plat = uap->port.dev->platform_data;
1803 if (plat->init)
1804 plat->init();
1805 }
1806
1807 uap->port.uartclk = clk_get_rate(uap->clk);
1808
1809 if (options)
1810 uart_parse_options(options, &baud, &parity, &bits, &flow);
1811 else
1812 pl011_console_get_options(uap, &baud, &parity, &bits);
1813
1814 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
1815 }
1816
1817 static struct uart_driver amba_reg;
1818 static struct console amba_console = {
1819 .name = "ttyAMA",
1820 .write = pl011_console_write,
1821 .device = uart_console_device,
1822 .setup = pl011_console_setup,
1823 .flags = CON_PRINTBUFFER,
1824 .index = -1,
1825 .data = &amba_reg,
1826 };
1827
1828 #define AMBA_CONSOLE (&amba_console)
1829 #else
1830 #define AMBA_CONSOLE NULL
1831 #endif
1832
1833 static struct uart_driver amba_reg = {
1834 .owner = THIS_MODULE,
1835 .driver_name = "ttyAMA",
1836 .dev_name = "ttyAMA",
1837 .major = SERIAL_AMBA_MAJOR,
1838 .minor = SERIAL_AMBA_MINOR,
1839 .nr = UART_NR,
1840 .cons = AMBA_CONSOLE,
1841 };
1842
1843 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
1844 {
1845 struct uart_amba_port *uap;
1846 struct vendor_data *vendor = id->data;
1847 struct pinctrl *pinctrl;
1848 void __iomem *base;
1849 int i, ret;
1850
1851 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1852 if (amba_ports[i] == NULL)
1853 break;
1854
1855 if (i == ARRAY_SIZE(amba_ports)) {
1856 ret = -EBUSY;
1857 goto out;
1858 }
1859
1860 uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
1861 if (uap == NULL) {
1862 ret = -ENOMEM;
1863 goto out;
1864 }
1865
1866 base = ioremap(dev->res.start, resource_size(&dev->res));
1867 if (!base) {
1868 ret = -ENOMEM;
1869 goto free;
1870 }
1871
1872 pinctrl = devm_pinctrl_get_select_default(&dev->dev);
1873 if (IS_ERR(pinctrl)) {
1874 ret = PTR_ERR(pinctrl);
1875 goto unmap;
1876 }
1877
1878 uap->clk = clk_get(&dev->dev, NULL);
1879 if (IS_ERR(uap->clk)) {
1880 ret = PTR_ERR(uap->clk);
1881 goto unmap;
1882 }
1883
1884 uap->vendor = vendor;
1885 uap->lcrh_rx = vendor->lcrh_rx;
1886 uap->lcrh_tx = vendor->lcrh_tx;
1887 uap->old_cr = 0;
1888 uap->fifosize = vendor->fifosize;
1889 uap->interrupt_may_hang = vendor->interrupt_may_hang;
1890 uap->port.dev = &dev->dev;
1891 uap->port.mapbase = dev->res.start;
1892 uap->port.membase = base;
1893 uap->port.iotype = UPIO_MEM;
1894 uap->port.irq = dev->irq[0];
1895 uap->port.fifosize = uap->fifosize;
1896 uap->port.ops = &amba_pl011_pops;
1897 uap->port.flags = UPF_BOOT_AUTOCONF;
1898 uap->port.line = i;
1899 pl011_dma_probe(uap);
1900
1901 /* Ensure interrupts from this UART are masked and cleared */
1902 writew(0, uap->port.membase + UART011_IMSC);
1903 writew(0xffff, uap->port.membase + UART011_ICR);
1904
1905 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
1906
1907 amba_ports[i] = uap;
1908
1909 amba_set_drvdata(dev, uap);
1910 ret = uart_add_one_port(&amba_reg, &uap->port);
1911 if (ret) {
1912 amba_set_drvdata(dev, NULL);
1913 amba_ports[i] = NULL;
1914 pl011_dma_remove(uap);
1915 clk_put(uap->clk);
1916 unmap:
1917 iounmap(base);
1918 free:
1919 kfree(uap);
1920 }
1921 out:
1922 return ret;
1923 }
1924
1925 static int pl011_remove(struct amba_device *dev)
1926 {
1927 struct uart_amba_port *uap = amba_get_drvdata(dev);
1928 int i;
1929
1930 amba_set_drvdata(dev, NULL);
1931
1932 uart_remove_one_port(&amba_reg, &uap->port);
1933
1934 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
1935 if (amba_ports[i] == uap)
1936 amba_ports[i] = NULL;
1937
1938 pl011_dma_remove(uap);
1939 iounmap(uap->port.membase);
1940 clk_put(uap->clk);
1941 kfree(uap);
1942 return 0;
1943 }
1944
1945 #ifdef CONFIG_PM
1946 static int pl011_suspend(struct amba_device *dev, pm_message_t state)
1947 {
1948 struct uart_amba_port *uap = amba_get_drvdata(dev);
1949
1950 if (!uap)
1951 return -EINVAL;
1952
1953 return uart_suspend_port(&amba_reg, &uap->port);
1954 }
1955
1956 static int pl011_resume(struct amba_device *dev)
1957 {
1958 struct uart_amba_port *uap = amba_get_drvdata(dev);
1959
1960 if (!uap)
1961 return -EINVAL;
1962
1963 return uart_resume_port(&amba_reg, &uap->port);
1964 }
1965 #endif
1966
1967 static struct amba_id pl011_ids[] = {
1968 {
1969 .id = 0x00041011,
1970 .mask = 0x000fffff,
1971 .data = &vendor_arm,
1972 },
1973 {
1974 .id = 0x00380802,
1975 .mask = 0x00ffffff,
1976 .data = &vendor_st,
1977 },
1978 { 0, 0 },
1979 };
1980
1981 MODULE_DEVICE_TABLE(amba, pl011_ids);
1982
1983 static struct amba_driver pl011_driver = {
1984 .drv = {
1985 .name = "uart-pl011",
1986 },
1987 .id_table = pl011_ids,
1988 .probe = pl011_probe,
1989 .remove = pl011_remove,
1990 #ifdef CONFIG_PM
1991 .suspend = pl011_suspend,
1992 .resume = pl011_resume,
1993 #endif
1994 };
1995
1996 static int __init pl011_init(void)
1997 {
1998 int ret;
1999 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
2000
2001 ret = uart_register_driver(&amba_reg);
2002 if (ret == 0) {
2003 ret = amba_driver_register(&pl011_driver);
2004 if (ret)
2005 uart_unregister_driver(&amba_reg);
2006 }
2007 return ret;
2008 }
2009
2010 static void __exit pl011_exit(void)
2011 {
2012 amba_driver_unregister(&pl011_driver);
2013 uart_unregister_driver(&amba_reg);
2014 }
2015
2016 /*
2017 * While this can be a module, if builtin it's most likely the console
2018 * So let's leave module_exit but move module_init to an earlier place
2019 */
2020 arch_initcall(pl011_init);
2021 module_exit(pl011_exit);
2022
2023 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
2024 MODULE_DESCRIPTION("ARM AMBA serial port driver");
2025 MODULE_LICENSE("GPL");
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