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Linux 4.8-rc8
[linux/fpc-iii.git] / drivers / tty / serial / amba-pl011.c
blob8a9e213387a79fcc335caad27520a68edf03f446
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
33 #if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
34 #define SUPPORT_SYSRQ
35 #endif
36
37 #include <linux/module.h>
38 #include <linux/ioport.h>
39 #include <linux/init.h>
40 #include <linux/console.h>
41 #include <linux/sysrq.h>
42 #include <linux/device.h>
43 #include <linux/tty.h>
44 #include <linux/tty_flip.h>
45 #include <linux/serial_core.h>
46 #include <linux/serial.h>
47 #include <linux/amba/bus.h>
48 #include <linux/amba/serial.h>
49 #include <linux/clk.h>
50 #include <linux/slab.h>
51 #include <linux/dmaengine.h>
52 #include <linux/dma-mapping.h>
53 #include <linux/scatterlist.h>
54 #include <linux/delay.h>
55 #include <linux/types.h>
56 #include <linux/of.h>
57 #include <linux/of_device.h>
58 #include <linux/pinctrl/consumer.h>
59 #include <linux/sizes.h>
60 #include <linux/io.h>
61 #include <linux/acpi.h>
62
63 #include "amba-pl011.h"
64
65 #define UART_NR 14
66
67 #define SERIAL_AMBA_MAJOR 204
68 #define SERIAL_AMBA_MINOR 64
69 #define SERIAL_AMBA_NR UART_NR
70
71 #define AMBA_ISR_PASS_LIMIT 256
72
73 #define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
74 #define UART_DUMMY_DR_RX (1 << 16)
75
76 static u16 pl011_std_offsets[REG_ARRAY_SIZE] = {
77 [REG_DR] = UART01x_DR,
78 [REG_FR] = UART01x_FR,
79 [REG_LCRH_RX] = UART011_LCRH,
80 [REG_LCRH_TX] = UART011_LCRH,
81 [REG_IBRD] = UART011_IBRD,
82 [REG_FBRD] = UART011_FBRD,
83 [REG_CR] = UART011_CR,
84 [REG_IFLS] = UART011_IFLS,
85 [REG_IMSC] = UART011_IMSC,
86 [REG_RIS] = UART011_RIS,
87 [REG_MIS] = UART011_MIS,
88 [REG_ICR] = UART011_ICR,
89 [REG_DMACR] = UART011_DMACR,
90 };
91
92 /* There is by now at least one vendor with differing details, so handle it */
93 struct vendor_data {
94 const u16 *reg_offset;
95 unsigned int ifls;
96 bool access_32b;
97 bool oversampling;
98 bool dma_threshold;
99 bool cts_event_workaround;
100 bool always_enabled;
101 bool fixed_options;
102
103 unsigned int (*get_fifosize)(struct amba_device *dev);
104 };
105
106 static unsigned int get_fifosize_arm(struct amba_device *dev)
107 {
108 return amba_rev(dev) < 3 ? 16 : 32;
109 }
110
111 static struct vendor_data vendor_arm = {
112 .reg_offset = pl011_std_offsets,
113 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
114 .oversampling = false,
115 .dma_threshold = false,
116 .cts_event_workaround = false,
117 .always_enabled = false,
118 .fixed_options = false,
119 .get_fifosize = get_fifosize_arm,
120 };
121
122 static struct vendor_data vendor_sbsa = {
123 .reg_offset = pl011_std_offsets,
124 .access_32b = true,
125 .oversampling = false,
126 .dma_threshold = false,
127 .cts_event_workaround = false,
128 .always_enabled = true,
129 .fixed_options = true,
130 };
131
132 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {
133 [REG_DR] = UART01x_DR,
134 [REG_ST_DMAWM] = ST_UART011_DMAWM,
135 [REG_ST_TIMEOUT] = ST_UART011_TIMEOUT,
136 [REG_FR] = UART01x_FR,
137 [REG_LCRH_RX] = ST_UART011_LCRH_RX,
138 [REG_LCRH_TX] = ST_UART011_LCRH_TX,
139 [REG_IBRD] = UART011_IBRD,
140 [REG_FBRD] = UART011_FBRD,
141 [REG_CR] = UART011_CR,
142 [REG_IFLS] = UART011_IFLS,
143 [REG_IMSC] = UART011_IMSC,
144 [REG_RIS] = UART011_RIS,
145 [REG_MIS] = UART011_MIS,
146 [REG_ICR] = UART011_ICR,
147 [REG_DMACR] = UART011_DMACR,
148 [REG_ST_XFCR] = ST_UART011_XFCR,
149 [REG_ST_XON1] = ST_UART011_XON1,
150 [REG_ST_XON2] = ST_UART011_XON2,
151 [REG_ST_XOFF1] = ST_UART011_XOFF1,
152 [REG_ST_XOFF2] = ST_UART011_XOFF2,
153 [REG_ST_ITCR] = ST_UART011_ITCR,
154 [REG_ST_ITIP] = ST_UART011_ITIP,
155 [REG_ST_ABCR] = ST_UART011_ABCR,
156 [REG_ST_ABIMSC] = ST_UART011_ABIMSC,
157 };
158
159 static unsigned int get_fifosize_st(struct amba_device *dev)
160 {
161 return 64;
162 }
163
164 static struct vendor_data vendor_st = {
165 .reg_offset = pl011_st_offsets,
166 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
167 .oversampling = true,
168 .dma_threshold = true,
169 .cts_event_workaround = true,
170 .always_enabled = false,
171 .fixed_options = false,
172 .get_fifosize = get_fifosize_st,
173 };
174
175 static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
176 [REG_DR] = ZX_UART011_DR,
177 [REG_FR] = ZX_UART011_FR,
178 [REG_LCRH_RX] = ZX_UART011_LCRH,
179 [REG_LCRH_TX] = ZX_UART011_LCRH,
180 [REG_IBRD] = ZX_UART011_IBRD,
181 [REG_FBRD] = ZX_UART011_FBRD,
182 [REG_CR] = ZX_UART011_CR,
183 [REG_IFLS] = ZX_UART011_IFLS,
184 [REG_IMSC] = ZX_UART011_IMSC,
185 [REG_RIS] = ZX_UART011_RIS,
186 [REG_MIS] = ZX_UART011_MIS,
187 [REG_ICR] = ZX_UART011_ICR,
188 [REG_DMACR] = ZX_UART011_DMACR,
189 };
190
191 static struct vendor_data vendor_zte __maybe_unused = {
192 .reg_offset = pl011_zte_offsets,
193 .access_32b = true,
194 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
195 .get_fifosize = get_fifosize_arm,
196 };
197
198 /* Deals with DMA transactions */
199
200 struct pl011_sgbuf {
201 struct scatterlist sg;
202 char *buf;
203 };
204
205 struct pl011_dmarx_data {
206 struct dma_chan *chan;
207 struct completion complete;
208 bool use_buf_b;
209 struct pl011_sgbuf sgbuf_a;
210 struct pl011_sgbuf sgbuf_b;
211 dma_cookie_t cookie;
212 bool running;
213 struct timer_list timer;
214 unsigned int last_residue;
215 unsigned long last_jiffies;
216 bool auto_poll_rate;
217 unsigned int poll_rate;
218 unsigned int poll_timeout;
219 };
220
221 struct pl011_dmatx_data {
222 struct dma_chan *chan;
223 struct scatterlist sg;
224 char *buf;
225 bool queued;
226 };
227
228 /*
229 * We wrap our port structure around the generic uart_port.
230 */
231 struct uart_amba_port {
232 struct uart_port port;
233 const u16 *reg_offset;
234 struct clk *clk;
235 const struct vendor_data *vendor;
236 unsigned int dmacr; /* dma control reg */
237 unsigned int im; /* interrupt mask */
238 unsigned int old_status;
239 unsigned int fifosize; /* vendor-specific */
240 unsigned int old_cr; /* state during shutdown */
241 bool autorts;
242 unsigned int fixed_baud; /* vendor-set fixed baud rate */
243 char type[12];
244 #ifdef CONFIG_DMA_ENGINE
245 /* DMA stuff */
246 bool using_tx_dma;
247 bool using_rx_dma;
248 struct pl011_dmarx_data dmarx;
249 struct pl011_dmatx_data dmatx;
250 bool dma_probed;
251 #endif
252 };
253
254 static unsigned int pl011_reg_to_offset(const struct uart_amba_port *uap,
255 unsigned int reg)
256 {
257 return uap->reg_offset[reg];
258 }
259
260 static unsigned int pl011_read(const struct uart_amba_port *uap,
261 unsigned int reg)
262 {
263 void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg);
264
265 return (uap->port.iotype == UPIO_MEM32) ?
266 readl_relaxed(addr) : readw_relaxed(addr);
267 }
268
269 static void pl011_write(unsigned int val, const struct uart_amba_port *uap,
270 unsigned int reg)
271 {
272 void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg);
273
274 if (uap->port.iotype == UPIO_MEM32)
275 writel_relaxed(val, addr);
276 else
277 writew_relaxed(val, addr);
278 }
279
280 /*
281 * Reads up to 256 characters from the FIFO or until it's empty and
282 * inserts them into the TTY layer. Returns the number of characters
283 * read from the FIFO.
284 */
285 static int pl011_fifo_to_tty(struct uart_amba_port *uap)
286 {
287 u16 status;
288 unsigned int ch, flag, max_count = 256;
289 int fifotaken = 0;
290
291 while (max_count--) {
292 status = pl011_read(uap, REG_FR);
293 if (status & UART01x_FR_RXFE)
294 break;
295
296 /* Take chars from the FIFO and update status */
297 ch = pl011_read(uap, REG_DR) | UART_DUMMY_DR_RX;
298 flag = TTY_NORMAL;
299 uap->port.icount.rx++;
300 fifotaken++;
301
302 if (unlikely(ch & UART_DR_ERROR)) {
303 if (ch & UART011_DR_BE) {
304 ch &= ~(UART011_DR_FE | UART011_DR_PE);
305 uap->port.icount.brk++;
306 if (uart_handle_break(&uap->port))
307 continue;
308 } else if (ch & UART011_DR_PE)
309 uap->port.icount.parity++;
310 else if (ch & UART011_DR_FE)
311 uap->port.icount.frame++;
312 if (ch & UART011_DR_OE)
313 uap->port.icount.overrun++;
314
315 ch &= uap->port.read_status_mask;
316
317 if (ch & UART011_DR_BE)
318 flag = TTY_BREAK;
319 else if (ch & UART011_DR_PE)
320 flag = TTY_PARITY;
321 else if (ch & UART011_DR_FE)
322 flag = TTY_FRAME;
323 }
324
325 if (uart_handle_sysrq_char(&uap->port, ch & 255))
326 continue;
327
328 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
329 }
330
331 return fifotaken;
332 }
333
334
335 /*
336 * All the DMA operation mode stuff goes inside this ifdef.
337 * This assumes that you have a generic DMA device interface,
338 * no custom DMA interfaces are supported.
339 */
340 #ifdef CONFIG_DMA_ENGINE
341
342 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE
343
344 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
345 enum dma_data_direction dir)
346 {
347 dma_addr_t dma_addr;
348
349 sg->buf = dma_alloc_coherent(chan->device->dev,
350 PL011_DMA_BUFFER_SIZE, &dma_addr, GFP_KERNEL);
351 if (!sg->buf)
352 return -ENOMEM;
353
354 sg_init_table(&sg->sg, 1);
355 sg_set_page(&sg->sg, phys_to_page(dma_addr),
356 PL011_DMA_BUFFER_SIZE, offset_in_page(dma_addr));
357 sg_dma_address(&sg->sg) = dma_addr;
358 sg_dma_len(&sg->sg) = PL011_DMA_BUFFER_SIZE;
359
360 return 0;
361 }
362
363 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
364 enum dma_data_direction dir)
365 {
366 if (sg->buf) {
367 dma_free_coherent(chan->device->dev,
368 PL011_DMA_BUFFER_SIZE, sg->buf,
369 sg_dma_address(&sg->sg));
370 }
371 }
372
373 static void pl011_dma_probe(struct uart_amba_port *uap)
374 {
375 /* DMA is the sole user of the platform data right now */
376 struct amba_pl011_data *plat = dev_get_platdata(uap->port.dev);
377 struct device *dev = uap->port.dev;
378 struct dma_slave_config tx_conf = {
379 .dst_addr = uap->port.mapbase +
380 pl011_reg_to_offset(uap, REG_DR),
381 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
382 .direction = DMA_MEM_TO_DEV,
383 .dst_maxburst = uap->fifosize >> 1,
384 .device_fc = false,
385 };
386 struct dma_chan *chan;
387 dma_cap_mask_t mask;
388
389 uap->dma_probed = true;
390 chan = dma_request_slave_channel_reason(dev, "tx");
391 if (IS_ERR(chan)) {
392 if (PTR_ERR(chan) == -EPROBE_DEFER) {
393 uap->dma_probed = false;
394 return;
395 }
396
397 /* We need platform data */
398 if (!plat || !plat->dma_filter) {
399 dev_info(uap->port.dev, "no DMA platform data\n");
400 return;
401 }
402
403 /* Try to acquire a generic DMA engine slave TX channel */
404 dma_cap_zero(mask);
405 dma_cap_set(DMA_SLAVE, mask);
406
407 chan = dma_request_channel(mask, plat->dma_filter,
408 plat->dma_tx_param);
409 if (!chan) {
410 dev_err(uap->port.dev, "no TX DMA channel!\n");
411 return;
412 }
413 }
414
415 dmaengine_slave_config(chan, &tx_conf);
416 uap->dmatx.chan = chan;
417
418 dev_info(uap->port.dev, "DMA channel TX %s\n",
419 dma_chan_name(uap->dmatx.chan));
420
421 /* Optionally make use of an RX channel as well */
422 chan = dma_request_slave_channel(dev, "rx");
423
424 if (!chan && plat && plat->dma_rx_param) {
425 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
426
427 if (!chan) {
428 dev_err(uap->port.dev, "no RX DMA channel!\n");
429 return;
430 }
431 }
432
433 if (chan) {
434 struct dma_slave_config rx_conf = {
435 .src_addr = uap->port.mapbase +
436 pl011_reg_to_offset(uap, REG_DR),
437 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
438 .direction = DMA_DEV_TO_MEM,
439 .src_maxburst = uap->fifosize >> 2,
440 .device_fc = false,
441 };
442 struct dma_slave_caps caps;
443
444 /*
445 * Some DMA controllers provide information on their capabilities.
446 * If the controller does, check for suitable residue processing
447 * otherwise assime all is well.
448 */
449 if (0 == dma_get_slave_caps(chan, &caps)) {
450 if (caps.residue_granularity ==
451 DMA_RESIDUE_GRANULARITY_DESCRIPTOR) {
452 dma_release_channel(chan);
453 dev_info(uap->port.dev,
454 "RX DMA disabled - no residue processing\n");
455 return;
456 }
457 }
458 dmaengine_slave_config(chan, &rx_conf);
459 uap->dmarx.chan = chan;
460
461 uap->dmarx.auto_poll_rate = false;
462 if (plat && plat->dma_rx_poll_enable) {
463 /* Set poll rate if specified. */
464 if (plat->dma_rx_poll_rate) {
465 uap->dmarx.auto_poll_rate = false;
466 uap->dmarx.poll_rate = plat->dma_rx_poll_rate;
467 } else {
468 /*
469 * 100 ms defaults to poll rate if not
470 * specified. This will be adjusted with
471 * the baud rate at set_termios.
472 */
473 uap->dmarx.auto_poll_rate = true;
474 uap->dmarx.poll_rate = 100;
475 }
476 /* 3 secs defaults poll_timeout if not specified. */
477 if (plat->dma_rx_poll_timeout)
478 uap->dmarx.poll_timeout =
479 plat->dma_rx_poll_timeout;
480 else
481 uap->dmarx.poll_timeout = 3000;
482 } else if (!plat && dev->of_node) {
483 uap->dmarx.auto_poll_rate = of_property_read_bool(
484 dev->of_node, "auto-poll");
485 if (uap->dmarx.auto_poll_rate) {
486 u32 x;
487
488 if (0 == of_property_read_u32(dev->of_node,
489 "poll-rate-ms", &x))
490 uap->dmarx.poll_rate = x;
491 else
492 uap->dmarx.poll_rate = 100;
493 if (0 == of_property_read_u32(dev->of_node,
494 "poll-timeout-ms", &x))
495 uap->dmarx.poll_timeout = x;
496 else
497 uap->dmarx.poll_timeout = 3000;
498 }
499 }
500 dev_info(uap->port.dev, "DMA channel RX %s\n",
501 dma_chan_name(uap->dmarx.chan));
502 }
503 }
504
505 static void pl011_dma_remove(struct uart_amba_port *uap)
506 {
507 if (uap->dmatx.chan)
508 dma_release_channel(uap->dmatx.chan);
509 if (uap->dmarx.chan)
510 dma_release_channel(uap->dmarx.chan);
511 }
512
513 /* Forward declare these for the refill routine */
514 static int pl011_dma_tx_refill(struct uart_amba_port *uap);
515 static void pl011_start_tx_pio(struct uart_amba_port *uap);
516
517 /*
518 * The current DMA TX buffer has been sent.
519 * Try to queue up another DMA buffer.
520 */
521 static void pl011_dma_tx_callback(void *data)
522 {
523 struct uart_amba_port *uap = data;
524 struct pl011_dmatx_data *dmatx = &uap->dmatx;
525 unsigned long flags;
526 u16 dmacr;
527
528 spin_lock_irqsave(&uap->port.lock, flags);
529 if (uap->dmatx.queued)
530 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
531 DMA_TO_DEVICE);
532
533 dmacr = uap->dmacr;
534 uap->dmacr = dmacr & ~UART011_TXDMAE;
535 pl011_write(uap->dmacr, uap, REG_DMACR);
536
537 /*
538 * If TX DMA was disabled, it means that we've stopped the DMA for
539 * some reason (eg, XOFF received, or we want to send an X-char.)
540 *
541 * Note: we need to be careful here of a potential race between DMA
542 * and the rest of the driver - if the driver disables TX DMA while
543 * a TX buffer completing, we must update the tx queued status to
544 * get further refills (hence we check dmacr).
545 */
546 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
547 uart_circ_empty(&uap->port.state->xmit)) {
548 uap->dmatx.queued = false;
549 spin_unlock_irqrestore(&uap->port.lock, flags);
550 return;
551 }
552
553 if (pl011_dma_tx_refill(uap) <= 0)
554 /*
555 * We didn't queue a DMA buffer for some reason, but we
556 * have data pending to be sent. Re-enable the TX IRQ.
557 */
558 pl011_start_tx_pio(uap);
559
560 spin_unlock_irqrestore(&uap->port.lock, flags);
561 }
562
563 /*
564 * Try to refill the TX DMA buffer.
565 * Locking: called with port lock held and IRQs disabled.
566 * Returns:
567 * 1 if we queued up a TX DMA buffer.
568 * 0 if we didn't want to handle this by DMA
569 * <0 on error
570 */
571 static int pl011_dma_tx_refill(struct uart_amba_port *uap)
572 {
573 struct pl011_dmatx_data *dmatx = &uap->dmatx;
574 struct dma_chan *chan = dmatx->chan;
575 struct dma_device *dma_dev = chan->device;
576 struct dma_async_tx_descriptor *desc;
577 struct circ_buf *xmit = &uap->port.state->xmit;
578 unsigned int count;
579
580 /*
581 * Try to avoid the overhead involved in using DMA if the
582 * transaction fits in the first half of the FIFO, by using
583 * the standard interrupt handling. This ensures that we
584 * issue a uart_write_wakeup() at the appropriate time.
585 */
586 count = uart_circ_chars_pending(xmit);
587 if (count < (uap->fifosize >> 1)) {
588 uap->dmatx.queued = false;
589 return 0;
590 }
591
592 /*
593 * Bodge: don't send the last character by DMA, as this
594 * will prevent XON from notifying us to restart DMA.
595 */
596 count -= 1;
597
598 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
599 if (count > PL011_DMA_BUFFER_SIZE)
600 count = PL011_DMA_BUFFER_SIZE;
601
602 if (xmit->tail < xmit->head)
603 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
604 else {
605 size_t first = UART_XMIT_SIZE - xmit->tail;
606 size_t second;
607
608 if (first > count)
609 first = count;
610 second = count - first;
611
612 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
613 if (second)
614 memcpy(&dmatx->buf[first], &xmit->buf[0], second);
615 }
616
617 dmatx->sg.length = count;
618
619 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
620 uap->dmatx.queued = false;
621 dev_dbg(uap->port.dev, "unable to map TX DMA\n");
622 return -EBUSY;
623 }
624
625 desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
626 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
627 if (!desc) {
628 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
629 uap->dmatx.queued = false;
630 /*
631 * If DMA cannot be used right now, we complete this
632 * transaction via IRQ and let the TTY layer retry.
633 */
634 dev_dbg(uap->port.dev, "TX DMA busy\n");
635 return -EBUSY;
636 }
637
638 /* Some data to go along to the callback */
639 desc->callback = pl011_dma_tx_callback;
640 desc->callback_param = uap;
641
642 /* All errors should happen at prepare time */
643 dmaengine_submit(desc);
644
645 /* Fire the DMA transaction */
646 dma_dev->device_issue_pending(chan);
647
648 uap->dmacr |= UART011_TXDMAE;
649 pl011_write(uap->dmacr, uap, REG_DMACR);
650 uap->dmatx.queued = true;
651
652 /*
653 * Now we know that DMA will fire, so advance the ring buffer
654 * with the stuff we just dispatched.
655 */
656 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
657 uap->port.icount.tx += count;
658
659 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
660 uart_write_wakeup(&uap->port);
661
662 return 1;
663 }
664
665 /*
666 * We received a transmit interrupt without a pending X-char but with
667 * pending characters.
668 * Locking: called with port lock held and IRQs disabled.
669 * Returns:
670 * false if we want to use PIO to transmit
671 * true if we queued a DMA buffer
672 */
673 static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
674 {
675 if (!uap->using_tx_dma)
676 return false;
677
678 /*
679 * If we already have a TX buffer queued, but received a
680 * TX interrupt, it will be because we've just sent an X-char.
681 * Ensure the TX DMA is enabled and the TX IRQ is disabled.
682 */
683 if (uap->dmatx.queued) {
684 uap->dmacr |= UART011_TXDMAE;
685 pl011_write(uap->dmacr, uap, REG_DMACR);
686 uap->im &= ~UART011_TXIM;
687 pl011_write(uap->im, uap, REG_IMSC);
688 return true;
689 }
690
691 /*
692 * We don't have a TX buffer queued, so try to queue one.
693 * If we successfully queued a buffer, mask the TX IRQ.
694 */
695 if (pl011_dma_tx_refill(uap) > 0) {
696 uap->im &= ~UART011_TXIM;
697 pl011_write(uap->im, uap, REG_IMSC);
698 return true;
699 }
700 return false;
701 }
702
703 /*
704 * Stop the DMA transmit (eg, due to received XOFF).
705 * Locking: called with port lock held and IRQs disabled.
706 */
707 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
708 {
709 if (uap->dmatx.queued) {
710 uap->dmacr &= ~UART011_TXDMAE;
711 pl011_write(uap->dmacr, uap, REG_DMACR);
712 }
713 }
714
715 /*
716 * Try to start a DMA transmit, or in the case of an XON/OFF
717 * character queued for send, try to get that character out ASAP.
718 * Locking: called with port lock held and IRQs disabled.
719 * Returns:
720 * false if we want the TX IRQ to be enabled
721 * true if we have a buffer queued
722 */
723 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
724 {
725 u16 dmacr;
726
727 if (!uap->using_tx_dma)
728 return false;
729
730 if (!uap->port.x_char) {
731 /* no X-char, try to push chars out in DMA mode */
732 bool ret = true;
733
734 if (!uap->dmatx.queued) {
735 if (pl011_dma_tx_refill(uap) > 0) {
736 uap->im &= ~UART011_TXIM;
737 pl011_write(uap->im, uap, REG_IMSC);
738 } else
739 ret = false;
740 } else if (!(uap->dmacr & UART011_TXDMAE)) {
741 uap->dmacr |= UART011_TXDMAE;
742 pl011_write(uap->dmacr, uap, REG_DMACR);
743 }
744 return ret;
745 }
746
747 /*
748 * We have an X-char to send. Disable DMA to prevent it loading
749 * the TX fifo, and then see if we can stuff it into the FIFO.
750 */
751 dmacr = uap->dmacr;
752 uap->dmacr &= ~UART011_TXDMAE;
753 pl011_write(uap->dmacr, uap, REG_DMACR);
754
755 if (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) {
756 /*
757 * No space in the FIFO, so enable the transmit interrupt
758 * so we know when there is space. Note that once we've
759 * loaded the character, we should just re-enable DMA.
760 */
761 return false;
762 }
763
764 pl011_write(uap->port.x_char, uap, REG_DR);
765 uap->port.icount.tx++;
766 uap->port.x_char = 0;
767
768 /* Success - restore the DMA state */
769 uap->dmacr = dmacr;
770 pl011_write(dmacr, uap, REG_DMACR);
771
772 return true;
773 }
774
775 /*
776 * Flush the transmit buffer.
777 * Locking: called with port lock held and IRQs disabled.
778 */
779 static void pl011_dma_flush_buffer(struct uart_port *port)
780 __releases(&uap->port.lock)
781 __acquires(&uap->port.lock)
782 {
783 struct uart_amba_port *uap =
784 container_of(port, struct uart_amba_port, port);
785
786 if (!uap->using_tx_dma)
787 return;
788
789 /* Avoid deadlock with the DMA engine callback */
790 spin_unlock(&uap->port.lock);
791 dmaengine_terminate_all(uap->dmatx.chan);
792 spin_lock(&uap->port.lock);
793 if (uap->dmatx.queued) {
794 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
795 DMA_TO_DEVICE);
796 uap->dmatx.queued = false;
797 uap->dmacr &= ~UART011_TXDMAE;
798 pl011_write(uap->dmacr, uap, REG_DMACR);
799 }
800 }
801
802 static void pl011_dma_rx_callback(void *data);
803
804 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
805 {
806 struct dma_chan *rxchan = uap->dmarx.chan;
807 struct pl011_dmarx_data *dmarx = &uap->dmarx;
808 struct dma_async_tx_descriptor *desc;
809 struct pl011_sgbuf *sgbuf;
810
811 if (!rxchan)
812 return -EIO;
813
814 /* Start the RX DMA job */
815 sgbuf = uap->dmarx.use_buf_b ?
816 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
817 desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
818 DMA_DEV_TO_MEM,
819 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
820 /*
821 * If the DMA engine is busy and cannot prepare a
822 * channel, no big deal, the driver will fall back
823 * to interrupt mode as a result of this error code.
824 */
825 if (!desc) {
826 uap->dmarx.running = false;
827 dmaengine_terminate_all(rxchan);
828 return -EBUSY;
829 }
830
831 /* Some data to go along to the callback */
832 desc->callback = pl011_dma_rx_callback;
833 desc->callback_param = uap;
834 dmarx->cookie = dmaengine_submit(desc);
835 dma_async_issue_pending(rxchan);
836
837 uap->dmacr |= UART011_RXDMAE;
838 pl011_write(uap->dmacr, uap, REG_DMACR);
839 uap->dmarx.running = true;
840
841 uap->im &= ~UART011_RXIM;
842 pl011_write(uap->im, uap, REG_IMSC);
843
844 return 0;
845 }
846
847 /*
848 * This is called when either the DMA job is complete, or
849 * the FIFO timeout interrupt occurred. This must be called
850 * with the port spinlock uap->port.lock held.
851 */
852 static void pl011_dma_rx_chars(struct uart_amba_port *uap,
853 u32 pending, bool use_buf_b,
854 bool readfifo)
855 {
856 struct tty_port *port = &uap->port.state->port;
857 struct pl011_sgbuf *sgbuf = use_buf_b ?
858 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
859 int dma_count = 0;
860 u32 fifotaken = 0; /* only used for vdbg() */
861
862 struct pl011_dmarx_data *dmarx = &uap->dmarx;
863 int dmataken = 0;
864
865 if (uap->dmarx.poll_rate) {
866 /* The data can be taken by polling */
867 dmataken = sgbuf->sg.length - dmarx->last_residue;
868 /* Recalculate the pending size */
869 if (pending >= dmataken)
870 pending -= dmataken;
871 }
872
873 /* Pick the remain data from the DMA */
874 if (pending) {
875
876 /*
877 * First take all chars in the DMA pipe, then look in the FIFO.
878 * Note that tty_insert_flip_buf() tries to take as many chars
879 * as it can.
880 */
881 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
882 pending);
883
884 uap->port.icount.rx += dma_count;
885 if (dma_count < pending)
886 dev_warn(uap->port.dev,
887 "couldn't insert all characters (TTY is full?)\n");
888 }
889
890 /* Reset the last_residue for Rx DMA poll */
891 if (uap->dmarx.poll_rate)
892 dmarx->last_residue = sgbuf->sg.length;
893
894 /*
895 * Only continue with trying to read the FIFO if all DMA chars have
896 * been taken first.
897 */
898 if (dma_count == pending && readfifo) {
899 /* Clear any error flags */
900 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS |
901 UART011_FEIS, uap, REG_ICR);
902
903 /*
904 * If we read all the DMA'd characters, and we had an
905 * incomplete buffer, that could be due to an rx error, or
906 * maybe we just timed out. Read any pending chars and check
907 * the error status.
908 *
909 * Error conditions will only occur in the FIFO, these will
910 * trigger an immediate interrupt and stop the DMA job, so we
911 * will always find the error in the FIFO, never in the DMA
912 * buffer.
913 */
914 fifotaken = pl011_fifo_to_tty(uap);
915 }
916
917 spin_unlock(&uap->port.lock);
918 dev_vdbg(uap->port.dev,
919 "Took %d chars from DMA buffer and %d chars from the FIFO\n",
920 dma_count, fifotaken);
921 tty_flip_buffer_push(port);
922 spin_lock(&uap->port.lock);
923 }
924
925 static void pl011_dma_rx_irq(struct uart_amba_port *uap)
926 {
927 struct pl011_dmarx_data *dmarx = &uap->dmarx;
928 struct dma_chan *rxchan = dmarx->chan;
929 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
930 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
931 size_t pending;
932 struct dma_tx_state state;
933 enum dma_status dmastat;
934
935 /*
936 * Pause the transfer so we can trust the current counter,
937 * do this before we pause the PL011 block, else we may
938 * overflow the FIFO.
939 */
940 if (dmaengine_pause(rxchan))
941 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
942 dmastat = rxchan->device->device_tx_status(rxchan,
943 dmarx->cookie, &state);
944 if (dmastat != DMA_PAUSED)
945 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
946
947 /* Disable RX DMA - incoming data will wait in the FIFO */
948 uap->dmacr &= ~UART011_RXDMAE;
949 pl011_write(uap->dmacr, uap, REG_DMACR);
950 uap->dmarx.running = false;
951
952 pending = sgbuf->sg.length - state.residue;
953 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
954 /* Then we terminate the transfer - we now know our residue */
955 dmaengine_terminate_all(rxchan);
956
957 /*
958 * This will take the chars we have so far and insert
959 * into the framework.
960 */
961 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
962
963 /* Switch buffer & re-trigger DMA job */
964 dmarx->use_buf_b = !dmarx->use_buf_b;
965 if (pl011_dma_rx_trigger_dma(uap)) {
966 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
967 "fall back to interrupt mode\n");
968 uap->im |= UART011_RXIM;
969 pl011_write(uap->im, uap, REG_IMSC);
970 }
971 }
972
973 static void pl011_dma_rx_callback(void *data)
974 {
975 struct uart_amba_port *uap = data;
976 struct pl011_dmarx_data *dmarx = &uap->dmarx;
977 struct dma_chan *rxchan = dmarx->chan;
978 bool lastbuf = dmarx->use_buf_b;
979 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
980 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
981 size_t pending;
982 struct dma_tx_state state;
983 int ret;
984
985 /*
986 * This completion interrupt occurs typically when the
987 * RX buffer is totally stuffed but no timeout has yet
988 * occurred. When that happens, we just want the RX
989 * routine to flush out the secondary DMA buffer while
990 * we immediately trigger the next DMA job.
991 */
992 spin_lock_irq(&uap->port.lock);
993 /*
994 * Rx data can be taken by the UART interrupts during
995 * the DMA irq handler. So we check the residue here.
996 */
997 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
998 pending = sgbuf->sg.length - state.residue;
999 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
1000 /* Then we terminate the transfer - we now know our residue */
1001 dmaengine_terminate_all(rxchan);
1002
1003 uap->dmarx.running = false;
1004 dmarx->use_buf_b = !lastbuf;
1005 ret = pl011_dma_rx_trigger_dma(uap);
1006
1007 pl011_dma_rx_chars(uap, pending, lastbuf, false);
1008 spin_unlock_irq(&uap->port.lock);
1009 /*
1010 * Do this check after we picked the DMA chars so we don't
1011 * get some IRQ immediately from RX.
1012 */
1013 if (ret) {
1014 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
1015 "fall back to interrupt mode\n");
1016 uap->im |= UART011_RXIM;
1017 pl011_write(uap->im, uap, REG_IMSC);
1018 }
1019 }
1020
1021 /*
1022 * Stop accepting received characters, when we're shutting down or
1023 * suspending this port.
1024 * Locking: called with port lock held and IRQs disabled.
1025 */
1026 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1027 {
1028 /* FIXME. Just disable the DMA enable */
1029 uap->dmacr &= ~UART011_RXDMAE;
1030 pl011_write(uap->dmacr, uap, REG_DMACR);
1031 }
1032
1033 /*
1034 * Timer handler for Rx DMA polling.
1035 * Every polling, It checks the residue in the dma buffer and transfer
1036 * data to the tty. Also, last_residue is updated for the next polling.
1037 */
1038 static void pl011_dma_rx_poll(unsigned long args)
1039 {
1040 struct uart_amba_port *uap = (struct uart_amba_port *)args;
1041 struct tty_port *port = &uap->port.state->port;
1042 struct pl011_dmarx_data *dmarx = &uap->dmarx;
1043 struct dma_chan *rxchan = uap->dmarx.chan;
1044 unsigned long flags = 0;
1045 unsigned int dmataken = 0;
1046 unsigned int size = 0;
1047 struct pl011_sgbuf *sgbuf;
1048 int dma_count;
1049 struct dma_tx_state state;
1050
1051 sgbuf = dmarx->use_buf_b ? &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
1052 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
1053 if (likely(state.residue < dmarx->last_residue)) {
1054 dmataken = sgbuf->sg.length - dmarx->last_residue;
1055 size = dmarx->last_residue - state.residue;
1056 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
1057 size);
1058 if (dma_count == size)
1059 dmarx->last_residue = state.residue;
1060 dmarx->last_jiffies = jiffies;
1061 }
1062 tty_flip_buffer_push(port);
1063
1064 /*
1065 * If no data is received in poll_timeout, the driver will fall back
1066 * to interrupt mode. We will retrigger DMA at the first interrupt.
1067 */
1068 if (jiffies_to_msecs(jiffies - dmarx->last_jiffies)
1069 > uap->dmarx.poll_timeout) {
1070
1071 spin_lock_irqsave(&uap->port.lock, flags);
1072 pl011_dma_rx_stop(uap);
1073 uap->im |= UART011_RXIM;
1074 pl011_write(uap->im, uap, REG_IMSC);
1075 spin_unlock_irqrestore(&uap->port.lock, flags);
1076
1077 uap->dmarx.running = false;
1078 dmaengine_terminate_all(rxchan);
1079 del_timer(&uap->dmarx.timer);
1080 } else {
1081 mod_timer(&uap->dmarx.timer,
1082 jiffies + msecs_to_jiffies(uap->dmarx.poll_rate));
1083 }
1084 }
1085
1086 static void pl011_dma_startup(struct uart_amba_port *uap)
1087 {
1088 int ret;
1089
1090 if (!uap->dma_probed)
1091 pl011_dma_probe(uap);
1092
1093 if (!uap->dmatx.chan)
1094 return;
1095
1096 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL | __GFP_DMA);
1097 if (!uap->dmatx.buf) {
1098 dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
1099 uap->port.fifosize = uap->fifosize;
1100 return;
1101 }
1102
1103 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
1104
1105 /* The DMA buffer is now the FIFO the TTY subsystem can use */
1106 uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
1107 uap->using_tx_dma = true;
1108
1109 if (!uap->dmarx.chan)
1110 goto skip_rx;
1111
1112 /* Allocate and map DMA RX buffers */
1113 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
1114 DMA_FROM_DEVICE);
1115 if (ret) {
1116 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
1117 "RX buffer A", ret);
1118 goto skip_rx;
1119 }
1120
1121 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
1122 DMA_FROM_DEVICE);
1123 if (ret) {
1124 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
1125 "RX buffer B", ret);
1126 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
1127 DMA_FROM_DEVICE);
1128 goto skip_rx;
1129 }
1130
1131 uap->using_rx_dma = true;
1132
1133 skip_rx:
1134 /* Turn on DMA error (RX/TX will be enabled on demand) */
1135 uap->dmacr |= UART011_DMAONERR;
1136 pl011_write(uap->dmacr, uap, REG_DMACR);
1137
1138 /*
1139 * ST Micro variants has some specific dma burst threshold
1140 * compensation. Set this to 16 bytes, so burst will only
1141 * be issued above/below 16 bytes.
1142 */
1143 if (uap->vendor->dma_threshold)
1144 pl011_write(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
1145 uap, REG_ST_DMAWM);
1146
1147 if (uap->using_rx_dma) {
1148 if (pl011_dma_rx_trigger_dma(uap))
1149 dev_dbg(uap->port.dev, "could not trigger initial "
1150 "RX DMA job, fall back to interrupt mode\n");
1151 if (uap->dmarx.poll_rate) {
1152 init_timer(&(uap->dmarx.timer));
1153 uap->dmarx.timer.function = pl011_dma_rx_poll;
1154 uap->dmarx.timer.data = (unsigned long)uap;
1155 mod_timer(&uap->dmarx.timer,
1156 jiffies +
1157 msecs_to_jiffies(uap->dmarx.poll_rate));
1158 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE;
1159 uap->dmarx.last_jiffies = jiffies;
1160 }
1161 }
1162 }
1163
1164 static void pl011_dma_shutdown(struct uart_amba_port *uap)
1165 {
1166 if (!(uap->using_tx_dma || uap->using_rx_dma))
1167 return;
1168
1169 /* Disable RX and TX DMA */
1170 while (pl011_read(uap, REG_FR) & UART01x_FR_BUSY)
1171 cpu_relax();
1172
1173 spin_lock_irq(&uap->port.lock);
1174 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
1175 pl011_write(uap->dmacr, uap, REG_DMACR);
1176 spin_unlock_irq(&uap->port.lock);
1177
1178 if (uap->using_tx_dma) {
1179 /* In theory, this should already be done by pl011_dma_flush_buffer */
1180 dmaengine_terminate_all(uap->dmatx.chan);
1181 if (uap->dmatx.queued) {
1182 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
1183 DMA_TO_DEVICE);
1184 uap->dmatx.queued = false;
1185 }
1186
1187 kfree(uap->dmatx.buf);
1188 uap->using_tx_dma = false;
1189 }
1190
1191 if (uap->using_rx_dma) {
1192 dmaengine_terminate_all(uap->dmarx.chan);
1193 /* Clean up the RX DMA */
1194 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
1195 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
1196 if (uap->dmarx.poll_rate)
1197 del_timer_sync(&uap->dmarx.timer);
1198 uap->using_rx_dma = false;
1199 }
1200 }
1201
1202 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1203 {
1204 return uap->using_rx_dma;
1205 }
1206
1207 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1208 {
1209 return uap->using_rx_dma && uap->dmarx.running;
1210 }
1211
1212 #else
1213 /* Blank functions if the DMA engine is not available */
1214 static inline void pl011_dma_probe(struct uart_amba_port *uap)
1215 {
1216 }
1217
1218 static inline void pl011_dma_remove(struct uart_amba_port *uap)
1219 {
1220 }
1221
1222 static inline void pl011_dma_startup(struct uart_amba_port *uap)
1223 {
1224 }
1225
1226 static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
1227 {
1228 }
1229
1230 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
1231 {
1232 return false;
1233 }
1234
1235 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
1236 {
1237 }
1238
1239 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
1240 {
1241 return false;
1242 }
1243
1244 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
1245 {
1246 }
1247
1248 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1249 {
1250 }
1251
1252 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
1253 {
1254 return -EIO;
1255 }
1256
1257 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1258 {
1259 return false;
1260 }
1261
1262 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1263 {
1264 return false;
1265 }
1266
1267 #define pl011_dma_flush_buffer NULL
1268 #endif
1269
1270 static void pl011_stop_tx(struct uart_port *port)
1271 {
1272 struct uart_amba_port *uap =
1273 container_of(port, struct uart_amba_port, port);
1274
1275 uap->im &= ~UART011_TXIM;
1276 pl011_write(uap->im, uap, REG_IMSC);
1277 pl011_dma_tx_stop(uap);
1278 }
1279
1280 static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq);
1281
1282 /* Start TX with programmed I/O only (no DMA) */
1283 static void pl011_start_tx_pio(struct uart_amba_port *uap)
1284 {
1285 uap->im |= UART011_TXIM;
1286 pl011_write(uap->im, uap, REG_IMSC);
1287 pl011_tx_chars(uap, false);
1288 }
1289
1290 static void pl011_start_tx(struct uart_port *port)
1291 {
1292 struct uart_amba_port *uap =
1293 container_of(port, struct uart_amba_port, port);
1294
1295 if (!pl011_dma_tx_start(uap))
1296 pl011_start_tx_pio(uap);
1297 }
1298
1299 static void pl011_stop_rx(struct uart_port *port)
1300 {
1301 struct uart_amba_port *uap =
1302 container_of(port, struct uart_amba_port, port);
1303
1304 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
1305 UART011_PEIM|UART011_BEIM|UART011_OEIM);
1306 pl011_write(uap->im, uap, REG_IMSC);
1307
1308 pl011_dma_rx_stop(uap);
1309 }
1310
1311 static void pl011_enable_ms(struct uart_port *port)
1312 {
1313 struct uart_amba_port *uap =
1314 container_of(port, struct uart_amba_port, port);
1315
1316 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
1317 pl011_write(uap->im, uap, REG_IMSC);
1318 }
1319
1320 static void pl011_rx_chars(struct uart_amba_port *uap)
1321 __releases(&uap->port.lock)
1322 __acquires(&uap->port.lock)
1323 {
1324 pl011_fifo_to_tty(uap);
1325
1326 spin_unlock(&uap->port.lock);
1327 tty_flip_buffer_push(&uap->port.state->port);
1328 /*
1329 * If we were temporarily out of DMA mode for a while,
1330 * attempt to switch back to DMA mode again.
1331 */
1332 if (pl011_dma_rx_available(uap)) {
1333 if (pl011_dma_rx_trigger_dma(uap)) {
1334 dev_dbg(uap->port.dev, "could not trigger RX DMA job "
1335 "fall back to interrupt mode again\n");
1336 uap->im |= UART011_RXIM;
1337 pl011_write(uap->im, uap, REG_IMSC);
1338 } else {
1339 #ifdef CONFIG_DMA_ENGINE
1340 /* Start Rx DMA poll */
1341 if (uap->dmarx.poll_rate) {
1342 uap->dmarx.last_jiffies = jiffies;
1343 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE;
1344 mod_timer(&uap->dmarx.timer,
1345 jiffies +
1346 msecs_to_jiffies(uap->dmarx.poll_rate));
1347 }
1348 #endif
1349 }
1350 }
1351 spin_lock(&uap->port.lock);
1352 }
1353
1354 static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c,
1355 bool from_irq)
1356 {
1357 if (unlikely(!from_irq) &&
1358 pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
1359 return false; /* unable to transmit character */
1360
1361 pl011_write(c, uap, REG_DR);
1362 uap->port.icount.tx++;
1363
1364 return true;
1365 }
1366
1367 static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
1368 {
1369 struct circ_buf *xmit = &uap->port.state->xmit;
1370 int count = uap->fifosize >> 1;
1371
1372 if (uap->port.x_char) {
1373 if (!pl011_tx_char(uap, uap->port.x_char, from_irq))
1374 return;
1375 uap->port.x_char = 0;
1376 --count;
1377 }
1378 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
1379 pl011_stop_tx(&uap->port);
1380 return;
1381 }
1382
1383 /* If we are using DMA mode, try to send some characters. */
1384 if (pl011_dma_tx_irq(uap))
1385 return;
1386
1387 do {
1388 if (likely(from_irq) && count-- == 0)
1389 break;
1390
1391 if (!pl011_tx_char(uap, xmit->buf[xmit->tail], from_irq))
1392 break;
1393
1394 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1395 } while (!uart_circ_empty(xmit));
1396
1397 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1398 uart_write_wakeup(&uap->port);
1399
1400 if (uart_circ_empty(xmit))
1401 pl011_stop_tx(&uap->port);
1402 }
1403
1404 static void pl011_modem_status(struct uart_amba_port *uap)
1405 {
1406 unsigned int status, delta;
1407
1408 status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY;
1409
1410 delta = status ^ uap->old_status;
1411 uap->old_status = status;
1412
1413 if (!delta)
1414 return;
1415
1416 if (delta & UART01x_FR_DCD)
1417 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
1418
1419 if (delta & UART01x_FR_DSR)
1420 uap->port.icount.dsr++;
1421
1422 if (delta & UART01x_FR_CTS)
1423 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
1424
1425 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
1426 }
1427
1428 static void check_apply_cts_event_workaround(struct uart_amba_port *uap)
1429 {
1430 unsigned int dummy_read;
1431
1432 if (!uap->vendor->cts_event_workaround)
1433 return;
1434
1435 /* workaround to make sure that all bits are unlocked.. */
1436 pl011_write(0x00, uap, REG_ICR);
1437
1438 /*
1439 * WA: introduce 26ns(1 uart clk) delay before W1C;
1440 * single apb access will incur 2 pclk(133.12Mhz) delay,
1441 * so add 2 dummy reads
1442 */
1443 dummy_read = pl011_read(uap, REG_ICR);
1444 dummy_read = pl011_read(uap, REG_ICR);
1445 }
1446
1447 static irqreturn_t pl011_int(int irq, void *dev_id)
1448 {
1449 struct uart_amba_port *uap = dev_id;
1450 unsigned long flags;
1451 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
1452 u16 imsc;
1453 int handled = 0;
1454
1455 spin_lock_irqsave(&uap->port.lock, flags);
1456 imsc = pl011_read(uap, REG_IMSC);
1457 status = pl011_read(uap, REG_RIS) & imsc;
1458 if (status) {
1459 do {
1460 check_apply_cts_event_workaround(uap);
1461
1462 pl011_write(status & ~(UART011_TXIS|UART011_RTIS|
1463 UART011_RXIS),
1464 uap, REG_ICR);
1465
1466 if (status & (UART011_RTIS|UART011_RXIS)) {
1467 if (pl011_dma_rx_running(uap))
1468 pl011_dma_rx_irq(uap);
1469 else
1470 pl011_rx_chars(uap);
1471 }
1472 if (status & (UART011_DSRMIS|UART011_DCDMIS|
1473 UART011_CTSMIS|UART011_RIMIS))
1474 pl011_modem_status(uap);
1475 if (status & UART011_TXIS)
1476 pl011_tx_chars(uap, true);
1477
1478 if (pass_counter-- == 0)
1479 break;
1480
1481 status = pl011_read(uap, REG_RIS) & imsc;
1482 } while (status != 0);
1483 handled = 1;
1484 }
1485
1486 spin_unlock_irqrestore(&uap->port.lock, flags);
1487
1488 return IRQ_RETVAL(handled);
1489 }
1490
1491 static unsigned int pl011_tx_empty(struct uart_port *port)
1492 {
1493 struct uart_amba_port *uap =
1494 container_of(port, struct uart_amba_port, port);
1495 unsigned int status = pl011_read(uap, REG_FR);
1496 return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
1497 }
1498
1499 static unsigned int pl011_get_mctrl(struct uart_port *port)
1500 {
1501 struct uart_amba_port *uap =
1502 container_of(port, struct uart_amba_port, port);
1503 unsigned int result = 0;
1504 unsigned int status = pl011_read(uap, REG_FR);
1505
1506 #define TIOCMBIT(uartbit, tiocmbit) \
1507 if (status & uartbit) \
1508 result |= tiocmbit
1509
1510 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
1511 TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
1512 TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
1513 TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
1514 #undef TIOCMBIT
1515 return result;
1516 }
1517
1518 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
1519 {
1520 struct uart_amba_port *uap =
1521 container_of(port, struct uart_amba_port, port);
1522 unsigned int cr;
1523
1524 cr = pl011_read(uap, REG_CR);
1525
1526 #define TIOCMBIT(tiocmbit, uartbit) \
1527 if (mctrl & tiocmbit) \
1528 cr |= uartbit; \
1529 else \
1530 cr &= ~uartbit
1531
1532 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
1533 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
1534 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
1535 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
1536 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
1537
1538 if (uap->autorts) {
1539 /* We need to disable auto-RTS if we want to turn RTS off */
1540 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
1541 }
1542 #undef TIOCMBIT
1543
1544 pl011_write(cr, uap, REG_CR);
1545 }
1546
1547 static void pl011_break_ctl(struct uart_port *port, int break_state)
1548 {
1549 struct uart_amba_port *uap =
1550 container_of(port, struct uart_amba_port, port);
1551 unsigned long flags;
1552 unsigned int lcr_h;
1553
1554 spin_lock_irqsave(&uap->port.lock, flags);
1555 lcr_h = pl011_read(uap, REG_LCRH_TX);
1556 if (break_state == -1)
1557 lcr_h |= UART01x_LCRH_BRK;
1558 else
1559 lcr_h &= ~UART01x_LCRH_BRK;
1560 pl011_write(lcr_h, uap, REG_LCRH_TX);
1561 spin_unlock_irqrestore(&uap->port.lock, flags);
1562 }
1563
1564 #ifdef CONFIG_CONSOLE_POLL
1565
1566 static void pl011_quiesce_irqs(struct uart_port *port)
1567 {
1568 struct uart_amba_port *uap =
1569 container_of(port, struct uart_amba_port, port);
1570
1571 pl011_write(pl011_read(uap, REG_MIS), uap, REG_ICR);
1572 /*
1573 * There is no way to clear TXIM as this is "ready to transmit IRQ", so
1574 * we simply mask it. start_tx() will unmask it.
1575 *
1576 * Note we can race with start_tx(), and if the race happens, the
1577 * polling user might get another interrupt just after we clear it.
1578 * But it should be OK and can happen even w/o the race, e.g.
1579 * controller immediately got some new data and raised the IRQ.
1580 *
1581 * And whoever uses polling routines assumes that it manages the device
1582 * (including tx queue), so we're also fine with start_tx()'s caller
1583 * side.
1584 */
1585 pl011_write(pl011_read(uap, REG_IMSC) & ~UART011_TXIM, uap,
1586 REG_IMSC);
1587 }
1588
1589 static int pl011_get_poll_char(struct uart_port *port)
1590 {
1591 struct uart_amba_port *uap =
1592 container_of(port, struct uart_amba_port, port);
1593 unsigned int status;
1594
1595 /*
1596 * The caller might need IRQs lowered, e.g. if used with KDB NMI
1597 * debugger.
1598 */
1599 pl011_quiesce_irqs(port);
1600
1601 status = pl011_read(uap, REG_FR);
1602 if (status & UART01x_FR_RXFE)
1603 return NO_POLL_CHAR;
1604
1605 return pl011_read(uap, REG_DR);
1606 }
1607
1608 static void pl011_put_poll_char(struct uart_port *port,
1609 unsigned char ch)
1610 {
1611 struct uart_amba_port *uap =
1612 container_of(port, struct uart_amba_port, port);
1613
1614 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
1615 cpu_relax();
1616
1617 pl011_write(ch, uap, REG_DR);
1618 }
1619
1620 #endif /* CONFIG_CONSOLE_POLL */
1621
1622 static int pl011_hwinit(struct uart_port *port)
1623 {
1624 struct uart_amba_port *uap =
1625 container_of(port, struct uart_amba_port, port);
1626 int retval;
1627
1628 /* Optionaly enable pins to be muxed in and configured */
1629 pinctrl_pm_select_default_state(port->dev);
1630
1631 /*
1632 * Try to enable the clock producer.
1633 */
1634 retval = clk_prepare_enable(uap->clk);
1635 if (retval)
1636 return retval;
1637
1638 uap->port.uartclk = clk_get_rate(uap->clk);
1639
1640 /* Clear pending error and receive interrupts */
1641 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS |
1642 UART011_FEIS | UART011_RTIS | UART011_RXIS,
1643 uap, REG_ICR);
1644
1645 /*
1646 * Save interrupts enable mask, and enable RX interrupts in case if
1647 * the interrupt is used for NMI entry.
1648 */
1649 uap->im = pl011_read(uap, REG_IMSC);
1650 pl011_write(UART011_RTIM | UART011_RXIM, uap, REG_IMSC);
1651
1652 if (dev_get_platdata(uap->port.dev)) {
1653 struct amba_pl011_data *plat;
1654
1655 plat = dev_get_platdata(uap->port.dev);
1656 if (plat->init)
1657 plat->init();
1658 }
1659 return 0;
1660 }
1661
1662 static bool pl011_split_lcrh(const struct uart_amba_port *uap)
1663 {
1664 return pl011_reg_to_offset(uap, REG_LCRH_RX) !=
1665 pl011_reg_to_offset(uap, REG_LCRH_TX);
1666 }
1667
1668 static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
1669 {
1670 pl011_write(lcr_h, uap, REG_LCRH_RX);
1671 if (pl011_split_lcrh(uap)) {
1672 int i;
1673 /*
1674 * Wait 10 PCLKs before writing LCRH_TX register,
1675 * to get this delay write read only register 10 times
1676 */
1677 for (i = 0; i < 10; ++i)
1678 pl011_write(0xff, uap, REG_MIS);
1679 pl011_write(lcr_h, uap, REG_LCRH_TX);
1680 }
1681 }
1682
1683 static int pl011_allocate_irq(struct uart_amba_port *uap)
1684 {
1685 pl011_write(uap->im, uap, REG_IMSC);
1686
1687 return request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
1688 }
1689
1690 /*
1691 * Enable interrupts, only timeouts when using DMA
1692 * if initial RX DMA job failed, start in interrupt mode
1693 * as well.
1694 */
1695 static void pl011_enable_interrupts(struct uart_amba_port *uap)
1696 {
1697 spin_lock_irq(&uap->port.lock);
1698
1699 /* Clear out any spuriously appearing RX interrupts */
1700 pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR);
1701 uap->im = UART011_RTIM;
1702 if (!pl011_dma_rx_running(uap))
1703 uap->im |= UART011_RXIM;
1704 pl011_write(uap->im, uap, REG_IMSC);
1705 spin_unlock_irq(&uap->port.lock);
1706 }
1707
1708 static int pl011_startup(struct uart_port *port)
1709 {
1710 struct uart_amba_port *uap =
1711 container_of(port, struct uart_amba_port, port);
1712 unsigned int cr;
1713 int retval;
1714
1715 retval = pl011_hwinit(port);
1716 if (retval)
1717 goto clk_dis;
1718
1719 retval = pl011_allocate_irq(uap);
1720 if (retval)
1721 goto clk_dis;
1722
1723 pl011_write(uap->vendor->ifls, uap, REG_IFLS);
1724
1725 spin_lock_irq(&uap->port.lock);
1726
1727 /* restore RTS and DTR */
1728 cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
1729 cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
1730 pl011_write(cr, uap, REG_CR);
1731
1732 spin_unlock_irq(&uap->port.lock);
1733
1734 /*
1735 * initialise the old status of the modem signals
1736 */
1737 uap->old_status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY;
1738
1739 /* Startup DMA */
1740 pl011_dma_startup(uap);
1741
1742 pl011_enable_interrupts(uap);
1743
1744 return 0;
1745
1746 clk_dis:
1747 clk_disable_unprepare(uap->clk);
1748 return retval;
1749 }
1750
1751 static int sbsa_uart_startup(struct uart_port *port)
1752 {
1753 struct uart_amba_port *uap =
1754 container_of(port, struct uart_amba_port, port);
1755 int retval;
1756
1757 retval = pl011_hwinit(port);
1758 if (retval)
1759 return retval;
1760
1761 retval = pl011_allocate_irq(uap);
1762 if (retval)
1763 return retval;
1764
1765 /* The SBSA UART does not support any modem status lines. */
1766 uap->old_status = 0;
1767
1768 pl011_enable_interrupts(uap);
1769
1770 return 0;
1771 }
1772
1773 static void pl011_shutdown_channel(struct uart_amba_port *uap,
1774 unsigned int lcrh)
1775 {
1776 unsigned long val;
1777
1778 val = pl011_read(uap, lcrh);
1779 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
1780 pl011_write(val, uap, lcrh);
1781 }
1782
1783 /*
1784 * disable the port. It should not disable RTS and DTR.
1785 * Also RTS and DTR state should be preserved to restore
1786 * it during startup().
1787 */
1788 static void pl011_disable_uart(struct uart_amba_port *uap)
1789 {
1790 unsigned int cr;
1791
1792 uap->autorts = false;
1793 spin_lock_irq(&uap->port.lock);
1794 cr = pl011_read(uap, REG_CR);
1795 uap->old_cr = cr;
1796 cr &= UART011_CR_RTS | UART011_CR_DTR;
1797 cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1798 pl011_write(cr, uap, REG_CR);
1799 spin_unlock_irq(&uap->port.lock);
1800
1801 /*
1802 * disable break condition and fifos
1803 */
1804 pl011_shutdown_channel(uap, REG_LCRH_RX);
1805 if (pl011_split_lcrh(uap))
1806 pl011_shutdown_channel(uap, REG_LCRH_TX);
1807 }
1808
1809 static void pl011_disable_interrupts(struct uart_amba_port *uap)
1810 {
1811 spin_lock_irq(&uap->port.lock);
1812
1813 /* mask all interrupts and clear all pending ones */
1814 uap->im = 0;
1815 pl011_write(uap->im, uap, REG_IMSC);
1816 pl011_write(0xffff, uap, REG_ICR);
1817
1818 spin_unlock_irq(&uap->port.lock);
1819 }
1820
1821 static void pl011_shutdown(struct uart_port *port)
1822 {
1823 struct uart_amba_port *uap =
1824 container_of(port, struct uart_amba_port, port);
1825
1826 pl011_disable_interrupts(uap);
1827
1828 pl011_dma_shutdown(uap);
1829
1830 free_irq(uap->port.irq, uap);
1831
1832 pl011_disable_uart(uap);
1833
1834 /*
1835 * Shut down the clock producer
1836 */
1837 clk_disable_unprepare(uap->clk);
1838 /* Optionally let pins go into sleep states */
1839 pinctrl_pm_select_sleep_state(port->dev);
1840
1841 if (dev_get_platdata(uap->port.dev)) {
1842 struct amba_pl011_data *plat;
1843
1844 plat = dev_get_platdata(uap->port.dev);
1845 if (plat->exit)
1846 plat->exit();
1847 }
1848
1849 if (uap->port.ops->flush_buffer)
1850 uap->port.ops->flush_buffer(port);
1851 }
1852
1853 static void sbsa_uart_shutdown(struct uart_port *port)
1854 {
1855 struct uart_amba_port *uap =
1856 container_of(port, struct uart_amba_port, port);
1857
1858 pl011_disable_interrupts(uap);
1859
1860 free_irq(uap->port.irq, uap);
1861
1862 if (uap->port.ops->flush_buffer)
1863 uap->port.ops->flush_buffer(port);
1864 }
1865
1866 static void
1867 pl011_setup_status_masks(struct uart_port *port, struct ktermios *termios)
1868 {
1869 port->read_status_mask = UART011_DR_OE | 255;
1870 if (termios->c_iflag & INPCK)
1871 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
1872 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1873 port->read_status_mask |= UART011_DR_BE;
1874
1875 /*
1876 * Characters to ignore
1877 */
1878 port->ignore_status_mask = 0;
1879 if (termios->c_iflag & IGNPAR)
1880 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
1881 if (termios->c_iflag & IGNBRK) {
1882 port->ignore_status_mask |= UART011_DR_BE;
1883 /*
1884 * If we're ignoring parity and break indicators,
1885 * ignore overruns too (for real raw support).
1886 */
1887 if (termios->c_iflag & IGNPAR)
1888 port->ignore_status_mask |= UART011_DR_OE;
1889 }
1890
1891 /*
1892 * Ignore all characters if CREAD is not set.
1893 */
1894 if ((termios->c_cflag & CREAD) == 0)
1895 port->ignore_status_mask |= UART_DUMMY_DR_RX;
1896 }
1897
1898 static void
1899 pl011_set_termios(struct uart_port *port, struct ktermios *termios,
1900 struct ktermios *old)
1901 {
1902 struct uart_amba_port *uap =
1903 container_of(port, struct uart_amba_port, port);
1904 unsigned int lcr_h, old_cr;
1905 unsigned long flags;
1906 unsigned int baud, quot, clkdiv;
1907
1908 if (uap->vendor->oversampling)
1909 clkdiv = 8;
1910 else
1911 clkdiv = 16;
1912
1913 /*
1914 * Ask the core to calculate the divisor for us.
1915 */
1916 baud = uart_get_baud_rate(port, termios, old, 0,
1917 port->uartclk / clkdiv);
1918 #ifdef CONFIG_DMA_ENGINE
1919 /*
1920 * Adjust RX DMA polling rate with baud rate if not specified.
1921 */
1922 if (uap->dmarx.auto_poll_rate)
1923 uap->dmarx.poll_rate = DIV_ROUND_UP(10000000, baud);
1924 #endif
1925
1926 if (baud > port->uartclk/16)
1927 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
1928 else
1929 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
1930
1931 switch (termios->c_cflag & CSIZE) {
1932 case CS5:
1933 lcr_h = UART01x_LCRH_WLEN_5;
1934 break;
1935 case CS6:
1936 lcr_h = UART01x_LCRH_WLEN_6;
1937 break;
1938 case CS7:
1939 lcr_h = UART01x_LCRH_WLEN_7;
1940 break;
1941 default: // CS8
1942 lcr_h = UART01x_LCRH_WLEN_8;
1943 break;
1944 }
1945 if (termios->c_cflag & CSTOPB)
1946 lcr_h |= UART01x_LCRH_STP2;
1947 if (termios->c_cflag & PARENB) {
1948 lcr_h |= UART01x_LCRH_PEN;
1949 if (!(termios->c_cflag & PARODD))
1950 lcr_h |= UART01x_LCRH_EPS;
1951 if (termios->c_cflag & CMSPAR)
1952 lcr_h |= UART011_LCRH_SPS;
1953 }
1954 if (uap->fifosize > 1)
1955 lcr_h |= UART01x_LCRH_FEN;
1956
1957 spin_lock_irqsave(&port->lock, flags);
1958
1959 /*
1960 * Update the per-port timeout.
1961 */
1962 uart_update_timeout(port, termios->c_cflag, baud);
1963
1964 pl011_setup_status_masks(port, termios);
1965
1966 if (UART_ENABLE_MS(port, termios->c_cflag))
1967 pl011_enable_ms(port);
1968
1969 /* first, disable everything */
1970 old_cr = pl011_read(uap, REG_CR);
1971 pl011_write(0, uap, REG_CR);
1972
1973 if (termios->c_cflag & CRTSCTS) {
1974 if (old_cr & UART011_CR_RTS)
1975 old_cr |= UART011_CR_RTSEN;
1976
1977 old_cr |= UART011_CR_CTSEN;
1978 uap->autorts = true;
1979 } else {
1980 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
1981 uap->autorts = false;
1982 }
1983
1984 if (uap->vendor->oversampling) {
1985 if (baud > port->uartclk / 16)
1986 old_cr |= ST_UART011_CR_OVSFACT;
1987 else
1988 old_cr &= ~ST_UART011_CR_OVSFACT;
1989 }
1990
1991 /*
1992 * Workaround for the ST Micro oversampling variants to
1993 * increase the bitrate slightly, by lowering the divisor,
1994 * to avoid delayed sampling of start bit at high speeds,
1995 * else we see data corruption.
1996 */
1997 if (uap->vendor->oversampling) {
1998 if ((baud >= 3000000) && (baud < 3250000) && (quot > 1))
1999 quot -= 1;
2000 else if ((baud > 3250000) && (quot > 2))
2001 quot -= 2;
2002 }
2003 /* Set baud rate */
2004 pl011_write(quot & 0x3f, uap, REG_FBRD);
2005 pl011_write(quot >> 6, uap, REG_IBRD);
2006
2007 /*
2008 * ----------v----------v----------v----------v-----
2009 * NOTE: REG_LCRH_TX and REG_LCRH_RX MUST BE WRITTEN AFTER
2010 * REG_FBRD & REG_IBRD.
2011 * ----------^----------^----------^----------^-----
2012 */
2013 pl011_write_lcr_h(uap, lcr_h);
2014 pl011_write(old_cr, uap, REG_CR);
2015
2016 spin_unlock_irqrestore(&port->lock, flags);
2017 }
2018
2019 static void
2020 sbsa_uart_set_termios(struct uart_port *port, struct ktermios *termios,
2021 struct ktermios *old)
2022 {
2023 struct uart_amba_port *uap =
2024 container_of(port, struct uart_amba_port, port);
2025 unsigned long flags;
2026
2027 tty_termios_encode_baud_rate(termios, uap->fixed_baud, uap->fixed_baud);
2028
2029 /* The SBSA UART only supports 8n1 without hardware flow control. */
2030 termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD);
2031 termios->c_cflag &= ~(CMSPAR | CRTSCTS);
2032 termios->c_cflag |= CS8 | CLOCAL;
2033
2034 spin_lock_irqsave(&port->lock, flags);
2035 uart_update_timeout(port, CS8, uap->fixed_baud);
2036 pl011_setup_status_masks(port, termios);
2037 spin_unlock_irqrestore(&port->lock, flags);
2038 }
2039
2040 static const char *pl011_type(struct uart_port *port)
2041 {
2042 struct uart_amba_port *uap =
2043 container_of(port, struct uart_amba_port, port);
2044 return uap->port.type == PORT_AMBA ? uap->type : NULL;
2045 }
2046
2047 /*
2048 * Release the memory region(s) being used by 'port'
2049 */
2050 static void pl011_release_port(struct uart_port *port)
2051 {
2052 release_mem_region(port->mapbase, SZ_4K);
2053 }
2054
2055 /*
2056 * Request the memory region(s) being used by 'port'
2057 */
2058 static int pl011_request_port(struct uart_port *port)
2059 {
2060 return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
2061 != NULL ? 0 : -EBUSY;
2062 }
2063
2064 /*
2065 * Configure/autoconfigure the port.
2066 */
2067 static void pl011_config_port(struct uart_port *port, int flags)
2068 {
2069 if (flags & UART_CONFIG_TYPE) {
2070 port->type = PORT_AMBA;
2071 pl011_request_port(port);
2072 }
2073 }
2074
2075 /*
2076 * verify the new serial_struct (for TIOCSSERIAL).
2077 */
2078 static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
2079 {
2080 int ret = 0;
2081 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
2082 ret = -EINVAL;
2083 if (ser->irq < 0 || ser->irq >= nr_irqs)
2084 ret = -EINVAL;
2085 if (ser->baud_base < 9600)
2086 ret = -EINVAL;
2087 return ret;
2088 }
2089
2090 static struct uart_ops amba_pl011_pops = {
2091 .tx_empty = pl011_tx_empty,
2092 .set_mctrl = pl011_set_mctrl,
2093 .get_mctrl = pl011_get_mctrl,
2094 .stop_tx = pl011_stop_tx,
2095 .start_tx = pl011_start_tx,
2096 .stop_rx = pl011_stop_rx,
2097 .enable_ms = pl011_enable_ms,
2098 .break_ctl = pl011_break_ctl,
2099 .startup = pl011_startup,
2100 .shutdown = pl011_shutdown,
2101 .flush_buffer = pl011_dma_flush_buffer,
2102 .set_termios = pl011_set_termios,
2103 .type = pl011_type,
2104 .release_port = pl011_release_port,
2105 .request_port = pl011_request_port,
2106 .config_port = pl011_config_port,
2107 .verify_port = pl011_verify_port,
2108 #ifdef CONFIG_CONSOLE_POLL
2109 .poll_init = pl011_hwinit,
2110 .poll_get_char = pl011_get_poll_char,
2111 .poll_put_char = pl011_put_poll_char,
2112 #endif
2113 };
2114
2115 static void sbsa_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
2116 {
2117 }
2118
2119 static unsigned int sbsa_uart_get_mctrl(struct uart_port *port)
2120 {
2121 return 0;
2122 }
2123
2124 static const struct uart_ops sbsa_uart_pops = {
2125 .tx_empty = pl011_tx_empty,
2126 .set_mctrl = sbsa_uart_set_mctrl,
2127 .get_mctrl = sbsa_uart_get_mctrl,
2128 .stop_tx = pl011_stop_tx,
2129 .start_tx = pl011_start_tx,
2130 .stop_rx = pl011_stop_rx,
2131 .startup = sbsa_uart_startup,
2132 .shutdown = sbsa_uart_shutdown,
2133 .set_termios = sbsa_uart_set_termios,
2134 .type = pl011_type,
2135 .release_port = pl011_release_port,
2136 .request_port = pl011_request_port,
2137 .config_port = pl011_config_port,
2138 .verify_port = pl011_verify_port,
2139 #ifdef CONFIG_CONSOLE_POLL
2140 .poll_init = pl011_hwinit,
2141 .poll_get_char = pl011_get_poll_char,
2142 .poll_put_char = pl011_put_poll_char,
2143 #endif
2144 };
2145
2146 static struct uart_amba_port *amba_ports[UART_NR];
2147
2148 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
2149
2150 static void pl011_console_putchar(struct uart_port *port, int ch)
2151 {
2152 struct uart_amba_port *uap =
2153 container_of(port, struct uart_amba_port, port);
2154
2155 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
2156 cpu_relax();
2157 pl011_write(ch, uap, REG_DR);
2158 }
2159
2160 static void
2161 pl011_console_write(struct console *co, const char *s, unsigned int count)
2162 {
2163 struct uart_amba_port *uap = amba_ports[co->index];
2164 unsigned int old_cr = 0, new_cr;
2165 unsigned long flags;
2166 int locked = 1;
2167
2168 clk_enable(uap->clk);
2169
2170 local_irq_save(flags);
2171 if (uap->port.sysrq)
2172 locked = 0;
2173 else if (oops_in_progress)
2174 locked = spin_trylock(&uap->port.lock);
2175 else
2176 spin_lock(&uap->port.lock);
2177
2178 /*
2179 * First save the CR then disable the interrupts
2180 */
2181 if (!uap->vendor->always_enabled) {
2182 old_cr = pl011_read(uap, REG_CR);
2183 new_cr = old_cr & ~UART011_CR_CTSEN;
2184 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
2185 pl011_write(new_cr, uap, REG_CR);
2186 }
2187
2188 uart_console_write(&uap->port, s, count, pl011_console_putchar);
2189
2190 /*
2191 * Finally, wait for transmitter to become empty
2192 * and restore the TCR
2193 */
2194 while (pl011_read(uap, REG_FR) & UART01x_FR_BUSY)
2195 cpu_relax();
2196 if (!uap->vendor->always_enabled)
2197 pl011_write(old_cr, uap, REG_CR);
2198
2199 if (locked)
2200 spin_unlock(&uap->port.lock);
2201 local_irq_restore(flags);
2202
2203 clk_disable(uap->clk);
2204 }
2205
2206 static void __init
2207 pl011_console_get_options(struct uart_amba_port *uap, int *baud,
2208 int *parity, int *bits)
2209 {
2210 if (pl011_read(uap, REG_CR) & UART01x_CR_UARTEN) {
2211 unsigned int lcr_h, ibrd, fbrd;
2212
2213 lcr_h = pl011_read(uap, REG_LCRH_TX);
2214
2215 *parity = 'n';
2216 if (lcr_h & UART01x_LCRH_PEN) {
2217 if (lcr_h & UART01x_LCRH_EPS)
2218 *parity = 'e';
2219 else
2220 *parity = 'o';
2221 }
2222
2223 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
2224 *bits = 7;
2225 else
2226 *bits = 8;
2227
2228 ibrd = pl011_read(uap, REG_IBRD);
2229 fbrd = pl011_read(uap, REG_FBRD);
2230
2231 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
2232
2233 if (uap->vendor->oversampling) {
2234 if (pl011_read(uap, REG_CR)
2235 & ST_UART011_CR_OVSFACT)
2236 *baud *= 2;
2237 }
2238 }
2239 }
2240
2241 static int __init pl011_console_setup(struct console *co, char *options)
2242 {
2243 struct uart_amba_port *uap;
2244 int baud = 38400;
2245 int bits = 8;
2246 int parity = 'n';
2247 int flow = 'n';
2248 int ret;
2249
2250 /*
2251 * Check whether an invalid uart number has been specified, and
2252 * if so, search for the first available port that does have
2253 * console support.
2254 */
2255 if (co->index >= UART_NR)
2256 co->index = 0;
2257 uap = amba_ports[co->index];
2258 if (!uap)
2259 return -ENODEV;
2260
2261 /* Allow pins to be muxed in and configured */
2262 pinctrl_pm_select_default_state(uap->port.dev);
2263
2264 ret = clk_prepare(uap->clk);
2265 if (ret)
2266 return ret;
2267
2268 if (dev_get_platdata(uap->port.dev)) {
2269 struct amba_pl011_data *plat;
2270
2271 plat = dev_get_platdata(uap->port.dev);
2272 if (plat->init)
2273 plat->init();
2274 }
2275
2276 uap->port.uartclk = clk_get_rate(uap->clk);
2277
2278 if (uap->vendor->fixed_options) {
2279 baud = uap->fixed_baud;
2280 } else {
2281 if (options)
2282 uart_parse_options(options,
2283 &baud, &parity, &bits, &flow);
2284 else
2285 pl011_console_get_options(uap, &baud, &parity, &bits);
2286 }
2287
2288 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
2289 }
2290
2291 static struct uart_driver amba_reg;
2292 static struct console amba_console = {
2293 .name = "ttyAMA",
2294 .write = pl011_console_write,
2295 .device = uart_console_device,
2296 .setup = pl011_console_setup,
2297 .flags = CON_PRINTBUFFER,
2298 .index = -1,
2299 .data = &amba_reg,
2300 };
2301
2302 #define AMBA_CONSOLE (&amba_console)
2303
2304 static void pl011_putc(struct uart_port *port, int c)
2305 {
2306 while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF)
2307 cpu_relax();
2308 if (port->iotype == UPIO_MEM32)
2309 writel(c, port->membase + UART01x_DR);
2310 else
2311 writeb(c, port->membase + UART01x_DR);
2312 while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY)
2313 cpu_relax();
2314 }
2315
2316 static void pl011_early_write(struct console *con, const char *s, unsigned n)
2317 {
2318 struct earlycon_device *dev = con->data;
2319
2320 uart_console_write(&dev->port, s, n, pl011_putc);
2321 }
2322
2323 static int __init pl011_early_console_setup(struct earlycon_device *device,
2324 const char *opt)
2325 {
2326 if (!device->port.membase)
2327 return -ENODEV;
2328
2329 device->con->write = pl011_early_write;
2330 return 0;
2331 }
2332 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
2333
2334 #else
2335 #define AMBA_CONSOLE NULL
2336 #endif
2337
2338 static struct uart_driver amba_reg = {
2339 .owner = THIS_MODULE,
2340 .driver_name = "ttyAMA",
2341 .dev_name = "ttyAMA",
2342 .major = SERIAL_AMBA_MAJOR,
2343 .minor = SERIAL_AMBA_MINOR,
2344 .nr = UART_NR,
2345 .cons = AMBA_CONSOLE,
2346 };
2347
2348 static int pl011_probe_dt_alias(int index, struct device *dev)
2349 {
2350 struct device_node *np;
2351 static bool seen_dev_with_alias = false;
2352 static bool seen_dev_without_alias = false;
2353 int ret = index;
2354
2355 if (!IS_ENABLED(CONFIG_OF))
2356 return ret;
2357
2358 np = dev->of_node;
2359 if (!np)
2360 return ret;
2361
2362 ret = of_alias_get_id(np, "serial");
2363 if (ret < 0) {
2364 seen_dev_without_alias = true;
2365 ret = index;
2366 } else {
2367 seen_dev_with_alias = true;
2368 if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) {
2369 dev_warn(dev, "requested serial port %d not available.\n", ret);
2370 ret = index;
2371 }
2372 }
2373
2374 if (seen_dev_with_alias && seen_dev_without_alias)
2375 dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n");
2376
2377 return ret;
2378 }
2379
2380 /* unregisters the driver also if no more ports are left */
2381 static void pl011_unregister_port(struct uart_amba_port *uap)
2382 {
2383 int i;
2384 bool busy = false;
2385
2386 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) {
2387 if (amba_ports[i] == uap)
2388 amba_ports[i] = NULL;
2389 else if (amba_ports[i])
2390 busy = true;
2391 }
2392 pl011_dma_remove(uap);
2393 if (!busy)
2394 uart_unregister_driver(&amba_reg);
2395 }
2396
2397 static int pl011_find_free_port(void)
2398 {
2399 int i;
2400
2401 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
2402 if (amba_ports[i] == NULL)
2403 return i;
2404
2405 return -EBUSY;
2406 }
2407
2408 static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
2409 struct resource *mmiobase, int index)
2410 {
2411 void __iomem *base;
2412
2413 base = devm_ioremap_resource(dev, mmiobase);
2414 if (IS_ERR(base))
2415 return PTR_ERR(base);
2416
2417 index = pl011_probe_dt_alias(index, dev);
2418
2419 uap->old_cr = 0;
2420 uap->port.dev = dev;
2421 uap->port.mapbase = mmiobase->start;
2422 uap->port.membase = base;
2423 uap->port.fifosize = uap->fifosize;
2424 uap->port.flags = UPF_BOOT_AUTOCONF;
2425 uap->port.line = index;
2426
2427 amba_ports[index] = uap;
2428
2429 return 0;
2430 }
2431
2432 static int pl011_register_port(struct uart_amba_port *uap)
2433 {
2434 int ret;
2435
2436 /* Ensure interrupts from this UART are masked and cleared */
2437 pl011_write(0, uap, REG_IMSC);
2438 pl011_write(0xffff, uap, REG_ICR);
2439
2440 if (!amba_reg.state) {
2441 ret = uart_register_driver(&amba_reg);
2442 if (ret < 0) {
2443 dev_err(uap->port.dev,
2444 "Failed to register AMBA-PL011 driver\n");
2445 return ret;
2446 }
2447 }
2448
2449 ret = uart_add_one_port(&amba_reg, &uap->port);
2450 if (ret)
2451 pl011_unregister_port(uap);
2452
2453 return ret;
2454 }
2455
2456 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
2457 {
2458 struct uart_amba_port *uap;
2459 struct vendor_data *vendor = id->data;
2460 int portnr, ret;
2461
2462 portnr = pl011_find_free_port();
2463 if (portnr < 0)
2464 return portnr;
2465
2466 uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
2467 GFP_KERNEL);
2468 if (!uap)
2469 return -ENOMEM;
2470
2471 uap->clk = devm_clk_get(&dev->dev, NULL);
2472 if (IS_ERR(uap->clk))
2473 return PTR_ERR(uap->clk);
2474
2475 uap->reg_offset = vendor->reg_offset;
2476 uap->vendor = vendor;
2477 uap->fifosize = vendor->get_fifosize(dev);
2478 uap->port.iotype = vendor->access_32b ? UPIO_MEM32 : UPIO_MEM;
2479 uap->port.irq = dev->irq[0];
2480 uap->port.ops = &amba_pl011_pops;
2481
2482 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
2483
2484 ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
2485 if (ret)
2486 return ret;
2487
2488 amba_set_drvdata(dev, uap);
2489
2490 return pl011_register_port(uap);
2491 }
2492
2493 static int pl011_remove(struct amba_device *dev)
2494 {
2495 struct uart_amba_port *uap = amba_get_drvdata(dev);
2496
2497 uart_remove_one_port(&amba_reg, &uap->port);
2498 pl011_unregister_port(uap);
2499 return 0;
2500 }
2501
2502 #ifdef CONFIG_PM_SLEEP
2503 static int pl011_suspend(struct device *dev)
2504 {
2505 struct uart_amba_port *uap = dev_get_drvdata(dev);
2506
2507 if (!uap)
2508 return -EINVAL;
2509
2510 return uart_suspend_port(&amba_reg, &uap->port);
2511 }
2512
2513 static int pl011_resume(struct device *dev)
2514 {
2515 struct uart_amba_port *uap = dev_get_drvdata(dev);
2516
2517 if (!uap)
2518 return -EINVAL;
2519
2520 return uart_resume_port(&amba_reg, &uap->port);
2521 }
2522 #endif
2523
2524 static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume);
2525
2526 static int sbsa_uart_probe(struct platform_device *pdev)
2527 {
2528 struct uart_amba_port *uap;
2529 struct resource *r;
2530 int portnr, ret;
2531 int baudrate;
2532
2533 /*
2534 * Check the mandatory baud rate parameter in the DT node early
2535 * so that we can easily exit with the error.
2536 */
2537 if (pdev->dev.of_node) {
2538 struct device_node *np = pdev->dev.of_node;
2539
2540 ret = of_property_read_u32(np, "current-speed", &baudrate);
2541 if (ret)
2542 return ret;
2543 } else {
2544 baudrate = 115200;
2545 }
2546
2547 portnr = pl011_find_free_port();
2548 if (portnr < 0)
2549 return portnr;
2550
2551 uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port),
2552 GFP_KERNEL);
2553 if (!uap)
2554 return -ENOMEM;
2555
2556 ret = platform_get_irq(pdev, 0);
2557 if (ret < 0) {
2558 dev_err(&pdev->dev, "cannot obtain irq\n");
2559 return ret;
2560 }
2561 uap->port.irq = ret;
2562
2563 uap->reg_offset = vendor_sbsa.reg_offset;
2564 uap->vendor = &vendor_sbsa;
2565 uap->fifosize = 32;
2566 uap->port.iotype = vendor_sbsa.access_32b ? UPIO_MEM32 : UPIO_MEM;
2567 uap->port.ops = &sbsa_uart_pops;
2568 uap->fixed_baud = baudrate;
2569
2570 snprintf(uap->type, sizeof(uap->type), "SBSA");
2571
2572 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2573
2574 ret = pl011_setup_port(&pdev->dev, uap, r, portnr);
2575 if (ret)
2576 return ret;
2577
2578 platform_set_drvdata(pdev, uap);
2579
2580 return pl011_register_port(uap);
2581 }
2582
2583 static int sbsa_uart_remove(struct platform_device *pdev)
2584 {
2585 struct uart_amba_port *uap = platform_get_drvdata(pdev);
2586
2587 uart_remove_one_port(&amba_reg, &uap->port);
2588 pl011_unregister_port(uap);
2589 return 0;
2590 }
2591
2592 static const struct of_device_id sbsa_uart_of_match[] = {
2593 { .compatible = "arm,sbsa-uart", },
2594 {},
2595 };
2596 MODULE_DEVICE_TABLE(of, sbsa_uart_of_match);
2597
2598 static const struct acpi_device_id sbsa_uart_acpi_match[] = {
2599 { "ARMH0011", 0 },
2600 {},
2601 };
2602 MODULE_DEVICE_TABLE(acpi, sbsa_uart_acpi_match);
2603
2604 static struct platform_driver arm_sbsa_uart_platform_driver = {
2605 .probe = sbsa_uart_probe,
2606 .remove = sbsa_uart_remove,
2607 .driver = {
2608 .name = "sbsa-uart",
2609 .of_match_table = of_match_ptr(sbsa_uart_of_match),
2610 .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match),
2611 },
2612 };
2613
2614 static struct amba_id pl011_ids[] = {
2615 {
2616 .id = 0x00041011,
2617 .mask = 0x000fffff,
2618 .data = &vendor_arm,
2619 },
2620 {
2621 .id = 0x00380802,
2622 .mask = 0x00ffffff,
2623 .data = &vendor_st,
2624 },
2625 { 0, 0 },
2626 };
2627
2628 MODULE_DEVICE_TABLE(amba, pl011_ids);
2629
2630 static struct amba_driver pl011_driver = {
2631 .drv = {
2632 .name = "uart-pl011",
2633 .pm = &pl011_dev_pm_ops,
2634 },
2635 .id_table = pl011_ids,
2636 .probe = pl011_probe,
2637 .remove = pl011_remove,
2638 };
2639
2640 static int __init pl011_init(void)
2641 {
2642 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
2643
2644 if (platform_driver_register(&arm_sbsa_uart_platform_driver))
2645 pr_warn("could not register SBSA UART platform driver\n");
2646 return amba_driver_register(&pl011_driver);
2647 }
2648
2649 static void __exit pl011_exit(void)
2650 {
2651 platform_driver_unregister(&arm_sbsa_uart_platform_driver);
2652 amba_driver_unregister(&pl011_driver);
2653 }
2654
2655 /*
2656 * While this can be a module, if builtin it's most likely the console
2657 * So let's leave module_exit but move module_init to an earlier place
2658 */
2659 arch_initcall(pl011_init);
2660 module_exit(pl011_exit);
2661
2662 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
2663 MODULE_DESCRIPTION("ARM AMBA serial port driver");
2664 MODULE_LICENSE("GPL");
Linux with added FPC-III support