projects / deliverable / linux.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
tty: amba-pl011: add support for ZTE UART (EXPERIMENTAL)
[deliverable/linux.git] / drivers / tty / serial / amba-pl011.c
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 .oversampling = false,
125 .dma_threshold = false,
126 .cts_event_workaround = false,
127 .always_enabled = true,
128 .fixed_options = true,
129 };
130
131 static u16 pl011_st_offsets[REG_ARRAY_SIZE] = {
132 [REG_DR] = UART01x_DR,
133 [REG_ST_DMAWM] = ST_UART011_DMAWM,
134 [REG_ST_TIMEOUT] = ST_UART011_TIMEOUT,
135 [REG_FR] = UART01x_FR,
136 [REG_LCRH_RX] = ST_UART011_LCRH_RX,
137 [REG_LCRH_TX] = ST_UART011_LCRH_TX,
138 [REG_IBRD] = UART011_IBRD,
139 [REG_FBRD] = UART011_FBRD,
140 [REG_CR] = UART011_CR,
141 [REG_IFLS] = UART011_IFLS,
142 [REG_IMSC] = UART011_IMSC,
143 [REG_RIS] = UART011_RIS,
144 [REG_MIS] = UART011_MIS,
145 [REG_ICR] = UART011_ICR,
146 [REG_DMACR] = UART011_DMACR,
147 [REG_ST_XFCR] = ST_UART011_XFCR,
148 [REG_ST_XON1] = ST_UART011_XON1,
149 [REG_ST_XON2] = ST_UART011_XON2,
150 [REG_ST_XOFF1] = ST_UART011_XOFF1,
151 [REG_ST_XOFF2] = ST_UART011_XOFF2,
152 [REG_ST_ITCR] = ST_UART011_ITCR,
153 [REG_ST_ITIP] = ST_UART011_ITIP,
154 [REG_ST_ABCR] = ST_UART011_ABCR,
155 [REG_ST_ABIMSC] = ST_UART011_ABIMSC,
156 };
157
158 static unsigned int get_fifosize_st(struct amba_device *dev)
159 {
160 return 64;
161 }
162
163 static struct vendor_data vendor_st = {
164 .reg_offset = pl011_st_offsets,
165 .ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
166 .oversampling = true,
167 .dma_threshold = true,
168 .cts_event_workaround = true,
169 .always_enabled = false,
170 .fixed_options = false,
171 .get_fifosize = get_fifosize_st,
172 };
173
174 static const u16 pl011_zte_offsets[REG_ARRAY_SIZE] = {
175 [REG_DR] = ZX_UART011_DR,
176 [REG_FR] = ZX_UART011_FR,
177 [REG_LCRH_RX] = ZX_UART011_LCRH,
178 [REG_LCRH_TX] = ZX_UART011_LCRH,
179 [REG_IBRD] = ZX_UART011_IBRD,
180 [REG_FBRD] = ZX_UART011_FBRD,
181 [REG_CR] = ZX_UART011_CR,
182 [REG_IFLS] = ZX_UART011_IFLS,
183 [REG_IMSC] = ZX_UART011_IMSC,
184 [REG_RIS] = ZX_UART011_RIS,
185 [REG_MIS] = ZX_UART011_MIS,
186 [REG_ICR] = ZX_UART011_ICR,
187 [REG_DMACR] = ZX_UART011_DMACR,
188 };
189
190 static struct vendor_data vendor_zte = {
191 .reg_offset = pl011_zte_offsets,
192 .access_32b = true,
193 .ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
194 .get_fifosize = get_fifosize_arm,
195 };
196
197 /* Deals with DMA transactions */
198
199 struct pl011_sgbuf {
200 struct scatterlist sg;
201 char *buf;
202 };
203
204 struct pl011_dmarx_data {
205 struct dma_chan *chan;
206 struct completion complete;
207 bool use_buf_b;
208 struct pl011_sgbuf sgbuf_a;
209 struct pl011_sgbuf sgbuf_b;
210 dma_cookie_t cookie;
211 bool running;
212 struct timer_list timer;
213 unsigned int last_residue;
214 unsigned long last_jiffies;
215 bool auto_poll_rate;
216 unsigned int poll_rate;
217 unsigned int poll_timeout;
218 };
219
220 struct pl011_dmatx_data {
221 struct dma_chan *chan;
222 struct scatterlist sg;
223 char *buf;
224 bool queued;
225 };
226
227 /*
228 * We wrap our port structure around the generic uart_port.
229 */
230 struct uart_amba_port {
231 struct uart_port port;
232 const u16 *reg_offset;
233 struct clk *clk;
234 const struct vendor_data *vendor;
235 unsigned int dmacr; /* dma control reg */
236 unsigned int im; /* interrupt mask */
237 unsigned int old_status;
238 unsigned int fifosize; /* vendor-specific */
239 unsigned int old_cr; /* state during shutdown */
240 bool autorts;
241 bool access_32b;
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->access_32b ? readl(addr) : readw(addr);
266 }
267
268 static void pl011_write(unsigned int val, const struct uart_amba_port *uap,
269 unsigned int reg)
270 {
271 void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg);
272
273 if (uap->access_32b)
274 writel(val, addr);
275 else
276 writew(val, addr);
277 }
278
279 /*
280 * Reads up to 256 characters from the FIFO or until it's empty and
281 * inserts them into the TTY layer. Returns the number of characters
282 * read from the FIFO.
283 */
284 static int pl011_fifo_to_tty(struct uart_amba_port *uap)
285 {
286 u16 status;
287 unsigned int ch, flag, max_count = 256;
288 int fifotaken = 0;
289
290 while (max_count--) {
291 status = pl011_read(uap, REG_FR);
292 if (status & UART01x_FR_RXFE)
293 break;
294
295 /* Take chars from the FIFO and update status */
296 ch = pl011_read(uap, REG_DR) | UART_DUMMY_DR_RX;
297 flag = TTY_NORMAL;
298 uap->port.icount.rx++;
299 fifotaken++;
300
301 if (unlikely(ch & UART_DR_ERROR)) {
302 if (ch & UART011_DR_BE) {
303 ch &= ~(UART011_DR_FE | UART011_DR_PE);
304 uap->port.icount.brk++;
305 if (uart_handle_break(&uap->port))
306 continue;
307 } else if (ch & UART011_DR_PE)
308 uap->port.icount.parity++;
309 else if (ch & UART011_DR_FE)
310 uap->port.icount.frame++;
311 if (ch & UART011_DR_OE)
312 uap->port.icount.overrun++;
313
314 ch &= uap->port.read_status_mask;
315
316 if (ch & UART011_DR_BE)
317 flag = TTY_BREAK;
318 else if (ch & UART011_DR_PE)
319 flag = TTY_PARITY;
320 else if (ch & UART011_DR_FE)
321 flag = TTY_FRAME;
322 }
323
324 if (uart_handle_sysrq_char(&uap->port, ch & 255))
325 continue;
326
327 uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
328 }
329
330 return fifotaken;
331 }
332
333
334 /*
335 * All the DMA operation mode stuff goes inside this ifdef.
336 * This assumes that you have a generic DMA device interface,
337 * no custom DMA interfaces are supported.
338 */
339 #ifdef CONFIG_DMA_ENGINE
340
341 #define PL011_DMA_BUFFER_SIZE PAGE_SIZE
342
343 static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
344 enum dma_data_direction dir)
345 {
346 dma_addr_t dma_addr;
347
348 sg->buf = dma_alloc_coherent(chan->device->dev,
349 PL011_DMA_BUFFER_SIZE, &dma_addr, GFP_KERNEL);
350 if (!sg->buf)
351 return -ENOMEM;
352
353 sg_init_table(&sg->sg, 1);
354 sg_set_page(&sg->sg, phys_to_page(dma_addr),
355 PL011_DMA_BUFFER_SIZE, offset_in_page(dma_addr));
356 sg_dma_address(&sg->sg) = dma_addr;
357 sg_dma_len(&sg->sg) = PL011_DMA_BUFFER_SIZE;
358
359 return 0;
360 }
361
362 static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
363 enum dma_data_direction dir)
364 {
365 if (sg->buf) {
366 dma_free_coherent(chan->device->dev,
367 PL011_DMA_BUFFER_SIZE, sg->buf,
368 sg_dma_address(&sg->sg));
369 }
370 }
371
372 static void pl011_dma_probe(struct uart_amba_port *uap)
373 {
374 /* DMA is the sole user of the platform data right now */
375 struct amba_pl011_data *plat = dev_get_platdata(uap->port.dev);
376 struct device *dev = uap->port.dev;
377 struct dma_slave_config tx_conf = {
378 .dst_addr = uap->port.mapbase +
379 pl011_reg_to_offset(uap, REG_DR),
380 .dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
381 .direction = DMA_MEM_TO_DEV,
382 .dst_maxburst = uap->fifosize >> 1,
383 .device_fc = false,
384 };
385 struct dma_chan *chan;
386 dma_cap_mask_t mask;
387
388 uap->dma_probed = true;
389 chan = dma_request_slave_channel_reason(dev, "tx");
390 if (IS_ERR(chan)) {
391 if (PTR_ERR(chan) == -EPROBE_DEFER) {
392 uap->dma_probed = false;
393 return;
394 }
395
396 /* We need platform data */
397 if (!plat || !plat->dma_filter) {
398 dev_info(uap->port.dev, "no DMA platform data\n");
399 return;
400 }
401
402 /* Try to acquire a generic DMA engine slave TX channel */
403 dma_cap_zero(mask);
404 dma_cap_set(DMA_SLAVE, mask);
405
406 chan = dma_request_channel(mask, plat->dma_filter,
407 plat->dma_tx_param);
408 if (!chan) {
409 dev_err(uap->port.dev, "no TX DMA channel!\n");
410 return;
411 }
412 }
413
414 dmaengine_slave_config(chan, &tx_conf);
415 uap->dmatx.chan = chan;
416
417 dev_info(uap->port.dev, "DMA channel TX %s\n",
418 dma_chan_name(uap->dmatx.chan));
419
420 /* Optionally make use of an RX channel as well */
421 chan = dma_request_slave_channel(dev, "rx");
422
423 if (!chan && plat->dma_rx_param) {
424 chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
425
426 if (!chan) {
427 dev_err(uap->port.dev, "no RX DMA channel!\n");
428 return;
429 }
430 }
431
432 if (chan) {
433 struct dma_slave_config rx_conf = {
434 .src_addr = uap->port.mapbase +
435 pl011_reg_to_offset(uap, REG_DR),
436 .src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
437 .direction = DMA_DEV_TO_MEM,
438 .src_maxburst = uap->fifosize >> 2,
439 .device_fc = false,
440 };
441 struct dma_slave_caps caps;
442
443 /*
444 * Some DMA controllers provide information on their capabilities.
445 * If the controller does, check for suitable residue processing
446 * otherwise assime all is well.
447 */
448 if (0 == dma_get_slave_caps(chan, &caps)) {
449 if (caps.residue_granularity ==
450 DMA_RESIDUE_GRANULARITY_DESCRIPTOR) {
451 dma_release_channel(chan);
452 dev_info(uap->port.dev,
453 "RX DMA disabled - no residue processing\n");
454 return;
455 }
456 }
457 dmaengine_slave_config(chan, &rx_conf);
458 uap->dmarx.chan = chan;
459
460 uap->dmarx.auto_poll_rate = false;
461 if (plat && plat->dma_rx_poll_enable) {
462 /* Set poll rate if specified. */
463 if (plat->dma_rx_poll_rate) {
464 uap->dmarx.auto_poll_rate = false;
465 uap->dmarx.poll_rate = plat->dma_rx_poll_rate;
466 } else {
467 /*
468 * 100 ms defaults to poll rate if not
469 * specified. This will be adjusted with
470 * the baud rate at set_termios.
471 */
472 uap->dmarx.auto_poll_rate = true;
473 uap->dmarx.poll_rate = 100;
474 }
475 /* 3 secs defaults poll_timeout if not specified. */
476 if (plat->dma_rx_poll_timeout)
477 uap->dmarx.poll_timeout =
478 plat->dma_rx_poll_timeout;
479 else
480 uap->dmarx.poll_timeout = 3000;
481 } else if (!plat && dev->of_node) {
482 uap->dmarx.auto_poll_rate = of_property_read_bool(
483 dev->of_node, "auto-poll");
484 if (uap->dmarx.auto_poll_rate) {
485 u32 x;
486
487 if (0 == of_property_read_u32(dev->of_node,
488 "poll-rate-ms", &x))
489 uap->dmarx.poll_rate = x;
490 else
491 uap->dmarx.poll_rate = 100;
492 if (0 == of_property_read_u32(dev->of_node,
493 "poll-timeout-ms", &x))
494 uap->dmarx.poll_timeout = x;
495 else
496 uap->dmarx.poll_timeout = 3000;
497 }
498 }
499 dev_info(uap->port.dev, "DMA channel RX %s\n",
500 dma_chan_name(uap->dmarx.chan));
501 }
502 }
503
504 static void pl011_dma_remove(struct uart_amba_port *uap)
505 {
506 if (uap->dmatx.chan)
507 dma_release_channel(uap->dmatx.chan);
508 if (uap->dmarx.chan)
509 dma_release_channel(uap->dmarx.chan);
510 }
511
512 /* Forward declare these for the refill routine */
513 static int pl011_dma_tx_refill(struct uart_amba_port *uap);
514 static void pl011_start_tx_pio(struct uart_amba_port *uap);
515
516 /*
517 * The current DMA TX buffer has been sent.
518 * Try to queue up another DMA buffer.
519 */
520 static void pl011_dma_tx_callback(void *data)
521 {
522 struct uart_amba_port *uap = data;
523 struct pl011_dmatx_data *dmatx = &uap->dmatx;
524 unsigned long flags;
525 u16 dmacr;
526
527 spin_lock_irqsave(&uap->port.lock, flags);
528 if (uap->dmatx.queued)
529 dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
530 DMA_TO_DEVICE);
531
532 dmacr = uap->dmacr;
533 uap->dmacr = dmacr & ~UART011_TXDMAE;
534 pl011_write(uap->dmacr, uap, REG_DMACR);
535
536 /*
537 * If TX DMA was disabled, it means that we've stopped the DMA for
538 * some reason (eg, XOFF received, or we want to send an X-char.)
539 *
540 * Note: we need to be careful here of a potential race between DMA
541 * and the rest of the driver - if the driver disables TX DMA while
542 * a TX buffer completing, we must update the tx queued status to
543 * get further refills (hence we check dmacr).
544 */
545 if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
546 uart_circ_empty(&uap->port.state->xmit)) {
547 uap->dmatx.queued = false;
548 spin_unlock_irqrestore(&uap->port.lock, flags);
549 return;
550 }
551
552 if (pl011_dma_tx_refill(uap) <= 0)
553 /*
554 * We didn't queue a DMA buffer for some reason, but we
555 * have data pending to be sent. Re-enable the TX IRQ.
556 */
557 pl011_start_tx_pio(uap);
558
559 spin_unlock_irqrestore(&uap->port.lock, flags);
560 }
561
562 /*
563 * Try to refill the TX DMA buffer.
564 * Locking: called with port lock held and IRQs disabled.
565 * Returns:
566 * 1 if we queued up a TX DMA buffer.
567 * 0 if we didn't want to handle this by DMA
568 * <0 on error
569 */
570 static int pl011_dma_tx_refill(struct uart_amba_port *uap)
571 {
572 struct pl011_dmatx_data *dmatx = &uap->dmatx;
573 struct dma_chan *chan = dmatx->chan;
574 struct dma_device *dma_dev = chan->device;
575 struct dma_async_tx_descriptor *desc;
576 struct circ_buf *xmit = &uap->port.state->xmit;
577 unsigned int count;
578
579 /*
580 * Try to avoid the overhead involved in using DMA if the
581 * transaction fits in the first half of the FIFO, by using
582 * the standard interrupt handling. This ensures that we
583 * issue a uart_write_wakeup() at the appropriate time.
584 */
585 count = uart_circ_chars_pending(xmit);
586 if (count < (uap->fifosize >> 1)) {
587 uap->dmatx.queued = false;
588 return 0;
589 }
590
591 /*
592 * Bodge: don't send the last character by DMA, as this
593 * will prevent XON from notifying us to restart DMA.
594 */
595 count -= 1;
596
597 /* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
598 if (count > PL011_DMA_BUFFER_SIZE)
599 count = PL011_DMA_BUFFER_SIZE;
600
601 if (xmit->tail < xmit->head)
602 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
603 else {
604 size_t first = UART_XMIT_SIZE - xmit->tail;
605 size_t second;
606
607 if (first > count)
608 first = count;
609 second = count - first;
610
611 memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
612 if (second)
613 memcpy(&dmatx->buf[first], &xmit->buf[0], second);
614 }
615
616 dmatx->sg.length = count;
617
618 if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
619 uap->dmatx.queued = false;
620 dev_dbg(uap->port.dev, "unable to map TX DMA\n");
621 return -EBUSY;
622 }
623
624 desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
625 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
626 if (!desc) {
627 dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
628 uap->dmatx.queued = false;
629 /*
630 * If DMA cannot be used right now, we complete this
631 * transaction via IRQ and let the TTY layer retry.
632 */
633 dev_dbg(uap->port.dev, "TX DMA busy\n");
634 return -EBUSY;
635 }
636
637 /* Some data to go along to the callback */
638 desc->callback = pl011_dma_tx_callback;
639 desc->callback_param = uap;
640
641 /* All errors should happen at prepare time */
642 dmaengine_submit(desc);
643
644 /* Fire the DMA transaction */
645 dma_dev->device_issue_pending(chan);
646
647 uap->dmacr |= UART011_TXDMAE;
648 pl011_write(uap->dmacr, uap, REG_DMACR);
649 uap->dmatx.queued = true;
650
651 /*
652 * Now we know that DMA will fire, so advance the ring buffer
653 * with the stuff we just dispatched.
654 */
655 xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
656 uap->port.icount.tx += count;
657
658 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
659 uart_write_wakeup(&uap->port);
660
661 return 1;
662 }
663
664 /*
665 * We received a transmit interrupt without a pending X-char but with
666 * pending characters.
667 * Locking: called with port lock held and IRQs disabled.
668 * Returns:
669 * false if we want to use PIO to transmit
670 * true if we queued a DMA buffer
671 */
672 static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
673 {
674 if (!uap->using_tx_dma)
675 return false;
676
677 /*
678 * If we already have a TX buffer queued, but received a
679 * TX interrupt, it will be because we've just sent an X-char.
680 * Ensure the TX DMA is enabled and the TX IRQ is disabled.
681 */
682 if (uap->dmatx.queued) {
683 uap->dmacr |= UART011_TXDMAE;
684 pl011_write(uap->dmacr, uap, REG_DMACR);
685 uap->im &= ~UART011_TXIM;
686 pl011_write(uap->im, uap, REG_IMSC);
687 return true;
688 }
689
690 /*
691 * We don't have a TX buffer queued, so try to queue one.
692 * If we successfully queued a buffer, mask the TX IRQ.
693 */
694 if (pl011_dma_tx_refill(uap) > 0) {
695 uap->im &= ~UART011_TXIM;
696 pl011_write(uap->im, uap, REG_IMSC);
697 return true;
698 }
699 return false;
700 }
701
702 /*
703 * Stop the DMA transmit (eg, due to received XOFF).
704 * Locking: called with port lock held and IRQs disabled.
705 */
706 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
707 {
708 if (uap->dmatx.queued) {
709 uap->dmacr &= ~UART011_TXDMAE;
710 pl011_write(uap->dmacr, uap, REG_DMACR);
711 }
712 }
713
714 /*
715 * Try to start a DMA transmit, or in the case of an XON/OFF
716 * character queued for send, try to get that character out ASAP.
717 * Locking: called with port lock held and IRQs disabled.
718 * Returns:
719 * false if we want the TX IRQ to be enabled
720 * true if we have a buffer queued
721 */
722 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
723 {
724 u16 dmacr;
725
726 if (!uap->using_tx_dma)
727 return false;
728
729 if (!uap->port.x_char) {
730 /* no X-char, try to push chars out in DMA mode */
731 bool ret = true;
732
733 if (!uap->dmatx.queued) {
734 if (pl011_dma_tx_refill(uap) > 0) {
735 uap->im &= ~UART011_TXIM;
736 pl011_write(uap->im, uap, REG_IMSC);
737 } else
738 ret = false;
739 } else if (!(uap->dmacr & UART011_TXDMAE)) {
740 uap->dmacr |= UART011_TXDMAE;
741 pl011_write(uap->dmacr, uap, REG_DMACR);
742 }
743 return ret;
744 }
745
746 /*
747 * We have an X-char to send. Disable DMA to prevent it loading
748 * the TX fifo, and then see if we can stuff it into the FIFO.
749 */
750 dmacr = uap->dmacr;
751 uap->dmacr &= ~UART011_TXDMAE;
752 pl011_write(uap->dmacr, uap, REG_DMACR);
753
754 if (pl011_read(uap, REG_FR) & UART01x_FR_TXFF) {
755 /*
756 * No space in the FIFO, so enable the transmit interrupt
757 * so we know when there is space. Note that once we've
758 * loaded the character, we should just re-enable DMA.
759 */
760 return false;
761 }
762
763 pl011_write(uap->port.x_char, uap, REG_DR);
764 uap->port.icount.tx++;
765 uap->port.x_char = 0;
766
767 /* Success - restore the DMA state */
768 uap->dmacr = dmacr;
769 pl011_write(dmacr, uap, REG_DMACR);
770
771 return true;
772 }
773
774 /*
775 * Flush the transmit buffer.
776 * Locking: called with port lock held and IRQs disabled.
777 */
778 static void pl011_dma_flush_buffer(struct uart_port *port)
779 __releases(&uap->port.lock)
780 __acquires(&uap->port.lock)
781 {
782 struct uart_amba_port *uap =
783 container_of(port, struct uart_amba_port, port);
784
785 if (!uap->using_tx_dma)
786 return;
787
788 /* Avoid deadlock with the DMA engine callback */
789 spin_unlock(&uap->port.lock);
790 dmaengine_terminate_all(uap->dmatx.chan);
791 spin_lock(&uap->port.lock);
792 if (uap->dmatx.queued) {
793 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
794 DMA_TO_DEVICE);
795 uap->dmatx.queued = false;
796 uap->dmacr &= ~UART011_TXDMAE;
797 pl011_write(uap->dmacr, uap, REG_DMACR);
798 }
799 }
800
801 static void pl011_dma_rx_callback(void *data);
802
803 static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
804 {
805 struct dma_chan *rxchan = uap->dmarx.chan;
806 struct pl011_dmarx_data *dmarx = &uap->dmarx;
807 struct dma_async_tx_descriptor *desc;
808 struct pl011_sgbuf *sgbuf;
809
810 if (!rxchan)
811 return -EIO;
812
813 /* Start the RX DMA job */
814 sgbuf = uap->dmarx.use_buf_b ?
815 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
816 desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
817 DMA_DEV_TO_MEM,
818 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
819 /*
820 * If the DMA engine is busy and cannot prepare a
821 * channel, no big deal, the driver will fall back
822 * to interrupt mode as a result of this error code.
823 */
824 if (!desc) {
825 uap->dmarx.running = false;
826 dmaengine_terminate_all(rxchan);
827 return -EBUSY;
828 }
829
830 /* Some data to go along to the callback */
831 desc->callback = pl011_dma_rx_callback;
832 desc->callback_param = uap;
833 dmarx->cookie = dmaengine_submit(desc);
834 dma_async_issue_pending(rxchan);
835
836 uap->dmacr |= UART011_RXDMAE;
837 pl011_write(uap->dmacr, uap, REG_DMACR);
838 uap->dmarx.running = true;
839
840 uap->im &= ~UART011_RXIM;
841 pl011_write(uap->im, uap, REG_IMSC);
842
843 return 0;
844 }
845
846 /*
847 * This is called when either the DMA job is complete, or
848 * the FIFO timeout interrupt occurred. This must be called
849 * with the port spinlock uap->port.lock held.
850 */
851 static void pl011_dma_rx_chars(struct uart_amba_port *uap,
852 u32 pending, bool use_buf_b,
853 bool readfifo)
854 {
855 struct tty_port *port = &uap->port.state->port;
856 struct pl011_sgbuf *sgbuf = use_buf_b ?
857 &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
858 int dma_count = 0;
859 u32 fifotaken = 0; /* only used for vdbg() */
860
861 struct pl011_dmarx_data *dmarx = &uap->dmarx;
862 int dmataken = 0;
863
864 if (uap->dmarx.poll_rate) {
865 /* The data can be taken by polling */
866 dmataken = sgbuf->sg.length - dmarx->last_residue;
867 /* Recalculate the pending size */
868 if (pending >= dmataken)
869 pending -= dmataken;
870 }
871
872 /* Pick the remain data from the DMA */
873 if (pending) {
874
875 /*
876 * First take all chars in the DMA pipe, then look in the FIFO.
877 * Note that tty_insert_flip_buf() tries to take as many chars
878 * as it can.
879 */
880 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
881 pending);
882
883 uap->port.icount.rx += dma_count;
884 if (dma_count < pending)
885 dev_warn(uap->port.dev,
886 "couldn't insert all characters (TTY is full?)\n");
887 }
888
889 /* Reset the last_residue for Rx DMA poll */
890 if (uap->dmarx.poll_rate)
891 dmarx->last_residue = sgbuf->sg.length;
892
893 /*
894 * Only continue with trying to read the FIFO if all DMA chars have
895 * been taken first.
896 */
897 if (dma_count == pending && readfifo) {
898 /* Clear any error flags */
899 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS |
900 UART011_FEIS, uap, REG_ICR);
901
902 /*
903 * If we read all the DMA'd characters, and we had an
904 * incomplete buffer, that could be due to an rx error, or
905 * maybe we just timed out. Read any pending chars and check
906 * the error status.
907 *
908 * Error conditions will only occur in the FIFO, these will
909 * trigger an immediate interrupt and stop the DMA job, so we
910 * will always find the error in the FIFO, never in the DMA
911 * buffer.
912 */
913 fifotaken = pl011_fifo_to_tty(uap);
914 }
915
916 spin_unlock(&uap->port.lock);
917 dev_vdbg(uap->port.dev,
918 "Took %d chars from DMA buffer and %d chars from the FIFO\n",
919 dma_count, fifotaken);
920 tty_flip_buffer_push(port);
921 spin_lock(&uap->port.lock);
922 }
923
924 static void pl011_dma_rx_irq(struct uart_amba_port *uap)
925 {
926 struct pl011_dmarx_data *dmarx = &uap->dmarx;
927 struct dma_chan *rxchan = dmarx->chan;
928 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
929 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
930 size_t pending;
931 struct dma_tx_state state;
932 enum dma_status dmastat;
933
934 /*
935 * Pause the transfer so we can trust the current counter,
936 * do this before we pause the PL011 block, else we may
937 * overflow the FIFO.
938 */
939 if (dmaengine_pause(rxchan))
940 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
941 dmastat = rxchan->device->device_tx_status(rxchan,
942 dmarx->cookie, &state);
943 if (dmastat != DMA_PAUSED)
944 dev_err(uap->port.dev, "unable to pause DMA transfer\n");
945
946 /* Disable RX DMA - incoming data will wait in the FIFO */
947 uap->dmacr &= ~UART011_RXDMAE;
948 pl011_write(uap->dmacr, uap, REG_DMACR);
949 uap->dmarx.running = false;
950
951 pending = sgbuf->sg.length - state.residue;
952 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
953 /* Then we terminate the transfer - we now know our residue */
954 dmaengine_terminate_all(rxchan);
955
956 /*
957 * This will take the chars we have so far and insert
958 * into the framework.
959 */
960 pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
961
962 /* Switch buffer & re-trigger DMA job */
963 dmarx->use_buf_b = !dmarx->use_buf_b;
964 if (pl011_dma_rx_trigger_dma(uap)) {
965 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
966 "fall back to interrupt mode\n");
967 uap->im |= UART011_RXIM;
968 pl011_write(uap->im, uap, REG_IMSC);
969 }
970 }
971
972 static void pl011_dma_rx_callback(void *data)
973 {
974 struct uart_amba_port *uap = data;
975 struct pl011_dmarx_data *dmarx = &uap->dmarx;
976 struct dma_chan *rxchan = dmarx->chan;
977 bool lastbuf = dmarx->use_buf_b;
978 struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
979 &dmarx->sgbuf_b : &dmarx->sgbuf_a;
980 size_t pending;
981 struct dma_tx_state state;
982 int ret;
983
984 /*
985 * This completion interrupt occurs typically when the
986 * RX buffer is totally stuffed but no timeout has yet
987 * occurred. When that happens, we just want the RX
988 * routine to flush out the secondary DMA buffer while
989 * we immediately trigger the next DMA job.
990 */
991 spin_lock_irq(&uap->port.lock);
992 /*
993 * Rx data can be taken by the UART interrupts during
994 * the DMA irq handler. So we check the residue here.
995 */
996 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
997 pending = sgbuf->sg.length - state.residue;
998 BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
999 /* Then we terminate the transfer - we now know our residue */
1000 dmaengine_terminate_all(rxchan);
1001
1002 uap->dmarx.running = false;
1003 dmarx->use_buf_b = !lastbuf;
1004 ret = pl011_dma_rx_trigger_dma(uap);
1005
1006 pl011_dma_rx_chars(uap, pending, lastbuf, false);
1007 spin_unlock_irq(&uap->port.lock);
1008 /*
1009 * Do this check after we picked the DMA chars so we don't
1010 * get some IRQ immediately from RX.
1011 */
1012 if (ret) {
1013 dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
1014 "fall back to interrupt mode\n");
1015 uap->im |= UART011_RXIM;
1016 pl011_write(uap->im, uap, REG_IMSC);
1017 }
1018 }
1019
1020 /*
1021 * Stop accepting received characters, when we're shutting down or
1022 * suspending this port.
1023 * Locking: called with port lock held and IRQs disabled.
1024 */
1025 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1026 {
1027 /* FIXME. Just disable the DMA enable */
1028 uap->dmacr &= ~UART011_RXDMAE;
1029 pl011_write(uap->dmacr, uap, REG_DMACR);
1030 }
1031
1032 /*
1033 * Timer handler for Rx DMA polling.
1034 * Every polling, It checks the residue in the dma buffer and transfer
1035 * data to the tty. Also, last_residue is updated for the next polling.
1036 */
1037 static void pl011_dma_rx_poll(unsigned long args)
1038 {
1039 struct uart_amba_port *uap = (struct uart_amba_port *)args;
1040 struct tty_port *port = &uap->port.state->port;
1041 struct pl011_dmarx_data *dmarx = &uap->dmarx;
1042 struct dma_chan *rxchan = uap->dmarx.chan;
1043 unsigned long flags = 0;
1044 unsigned int dmataken = 0;
1045 unsigned int size = 0;
1046 struct pl011_sgbuf *sgbuf;
1047 int dma_count;
1048 struct dma_tx_state state;
1049
1050 sgbuf = dmarx->use_buf_b ? &uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
1051 rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
1052 if (likely(state.residue < dmarx->last_residue)) {
1053 dmataken = sgbuf->sg.length - dmarx->last_residue;
1054 size = dmarx->last_residue - state.residue;
1055 dma_count = tty_insert_flip_string(port, sgbuf->buf + dmataken,
1056 size);
1057 if (dma_count == size)
1058 dmarx->last_residue = state.residue;
1059 dmarx->last_jiffies = jiffies;
1060 }
1061 tty_flip_buffer_push(port);
1062
1063 /*
1064 * If no data is received in poll_timeout, the driver will fall back
1065 * to interrupt mode. We will retrigger DMA at the first interrupt.
1066 */
1067 if (jiffies_to_msecs(jiffies - dmarx->last_jiffies)
1068 > uap->dmarx.poll_timeout) {
1069
1070 spin_lock_irqsave(&uap->port.lock, flags);
1071 pl011_dma_rx_stop(uap);
1072 uap->im |= UART011_RXIM;
1073 pl011_write(uap->im, uap, REG_IMSC);
1074 spin_unlock_irqrestore(&uap->port.lock, flags);
1075
1076 uap->dmarx.running = false;
1077 dmaengine_terminate_all(rxchan);
1078 del_timer(&uap->dmarx.timer);
1079 } else {
1080 mod_timer(&uap->dmarx.timer,
1081 jiffies + msecs_to_jiffies(uap->dmarx.poll_rate));
1082 }
1083 }
1084
1085 static void pl011_dma_startup(struct uart_amba_port *uap)
1086 {
1087 int ret;
1088
1089 if (!uap->dma_probed)
1090 pl011_dma_probe(uap);
1091
1092 if (!uap->dmatx.chan)
1093 return;
1094
1095 uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL | __GFP_DMA);
1096 if (!uap->dmatx.buf) {
1097 dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
1098 uap->port.fifosize = uap->fifosize;
1099 return;
1100 }
1101
1102 sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
1103
1104 /* The DMA buffer is now the FIFO the TTY subsystem can use */
1105 uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
1106 uap->using_tx_dma = true;
1107
1108 if (!uap->dmarx.chan)
1109 goto skip_rx;
1110
1111 /* Allocate and map DMA RX buffers */
1112 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
1113 DMA_FROM_DEVICE);
1114 if (ret) {
1115 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
1116 "RX buffer A", ret);
1117 goto skip_rx;
1118 }
1119
1120 ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
1121 DMA_FROM_DEVICE);
1122 if (ret) {
1123 dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
1124 "RX buffer B", ret);
1125 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
1126 DMA_FROM_DEVICE);
1127 goto skip_rx;
1128 }
1129
1130 uap->using_rx_dma = true;
1131
1132 skip_rx:
1133 /* Turn on DMA error (RX/TX will be enabled on demand) */
1134 uap->dmacr |= UART011_DMAONERR;
1135 pl011_write(uap->dmacr, uap, REG_DMACR);
1136
1137 /*
1138 * ST Micro variants has some specific dma burst threshold
1139 * compensation. Set this to 16 bytes, so burst will only
1140 * be issued above/below 16 bytes.
1141 */
1142 if (uap->vendor->dma_threshold)
1143 pl011_write(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
1144 uap, REG_ST_DMAWM);
1145
1146 if (uap->using_rx_dma) {
1147 if (pl011_dma_rx_trigger_dma(uap))
1148 dev_dbg(uap->port.dev, "could not trigger initial "
1149 "RX DMA job, fall back to interrupt mode\n");
1150 if (uap->dmarx.poll_rate) {
1151 init_timer(&(uap->dmarx.timer));
1152 uap->dmarx.timer.function = pl011_dma_rx_poll;
1153 uap->dmarx.timer.data = (unsigned long)uap;
1154 mod_timer(&uap->dmarx.timer,
1155 jiffies +
1156 msecs_to_jiffies(uap->dmarx.poll_rate));
1157 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE;
1158 uap->dmarx.last_jiffies = jiffies;
1159 }
1160 }
1161 }
1162
1163 static void pl011_dma_shutdown(struct uart_amba_port *uap)
1164 {
1165 if (!(uap->using_tx_dma || uap->using_rx_dma))
1166 return;
1167
1168 /* Disable RX and TX DMA */
1169 while (pl011_read(uap, REG_FR) & UART01x_FR_BUSY)
1170 barrier();
1171
1172 spin_lock_irq(&uap->port.lock);
1173 uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
1174 pl011_write(uap->dmacr, uap, REG_DMACR);
1175 spin_unlock_irq(&uap->port.lock);
1176
1177 if (uap->using_tx_dma) {
1178 /* In theory, this should already be done by pl011_dma_flush_buffer */
1179 dmaengine_terminate_all(uap->dmatx.chan);
1180 if (uap->dmatx.queued) {
1181 dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
1182 DMA_TO_DEVICE);
1183 uap->dmatx.queued = false;
1184 }
1185
1186 kfree(uap->dmatx.buf);
1187 uap->using_tx_dma = false;
1188 }
1189
1190 if (uap->using_rx_dma) {
1191 dmaengine_terminate_all(uap->dmarx.chan);
1192 /* Clean up the RX DMA */
1193 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
1194 pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
1195 if (uap->dmarx.poll_rate)
1196 del_timer_sync(&uap->dmarx.timer);
1197 uap->using_rx_dma = false;
1198 }
1199 }
1200
1201 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1202 {
1203 return uap->using_rx_dma;
1204 }
1205
1206 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1207 {
1208 return uap->using_rx_dma && uap->dmarx.running;
1209 }
1210
1211 #else
1212 /* Blank functions if the DMA engine is not available */
1213 static inline void pl011_dma_probe(struct uart_amba_port *uap)
1214 {
1215 }
1216
1217 static inline void pl011_dma_remove(struct uart_amba_port *uap)
1218 {
1219 }
1220
1221 static inline void pl011_dma_startup(struct uart_amba_port *uap)
1222 {
1223 }
1224
1225 static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
1226 {
1227 }
1228
1229 static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
1230 {
1231 return false;
1232 }
1233
1234 static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
1235 {
1236 }
1237
1238 static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
1239 {
1240 return false;
1241 }
1242
1243 static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
1244 {
1245 }
1246
1247 static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
1248 {
1249 }
1250
1251 static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
1252 {
1253 return -EIO;
1254 }
1255
1256 static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
1257 {
1258 return false;
1259 }
1260
1261 static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
1262 {
1263 return false;
1264 }
1265
1266 #define pl011_dma_flush_buffer NULL
1267 #endif
1268
1269 static void pl011_stop_tx(struct uart_port *port)
1270 {
1271 struct uart_amba_port *uap =
1272 container_of(port, struct uart_amba_port, port);
1273
1274 uap->im &= ~UART011_TXIM;
1275 pl011_write(uap->im, uap, REG_IMSC);
1276 pl011_dma_tx_stop(uap);
1277 }
1278
1279 static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq);
1280
1281 /* Start TX with programmed I/O only (no DMA) */
1282 static void pl011_start_tx_pio(struct uart_amba_port *uap)
1283 {
1284 uap->im |= UART011_TXIM;
1285 pl011_write(uap->im, uap, REG_IMSC);
1286 pl011_tx_chars(uap, false);
1287 }
1288
1289 static void pl011_start_tx(struct uart_port *port)
1290 {
1291 struct uart_amba_port *uap =
1292 container_of(port, struct uart_amba_port, port);
1293
1294 if (!pl011_dma_tx_start(uap))
1295 pl011_start_tx_pio(uap);
1296 }
1297
1298 static void pl011_stop_rx(struct uart_port *port)
1299 {
1300 struct uart_amba_port *uap =
1301 container_of(port, struct uart_amba_port, port);
1302
1303 uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
1304 UART011_PEIM|UART011_BEIM|UART011_OEIM);
1305 pl011_write(uap->im, uap, REG_IMSC);
1306
1307 pl011_dma_rx_stop(uap);
1308 }
1309
1310 static void pl011_enable_ms(struct uart_port *port)
1311 {
1312 struct uart_amba_port *uap =
1313 container_of(port, struct uart_amba_port, port);
1314
1315 uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
1316 pl011_write(uap->im, uap, REG_IMSC);
1317 }
1318
1319 static void pl011_rx_chars(struct uart_amba_port *uap)
1320 __releases(&uap->port.lock)
1321 __acquires(&uap->port.lock)
1322 {
1323 pl011_fifo_to_tty(uap);
1324
1325 spin_unlock(&uap->port.lock);
1326 tty_flip_buffer_push(&uap->port.state->port);
1327 /*
1328 * If we were temporarily out of DMA mode for a while,
1329 * attempt to switch back to DMA mode again.
1330 */
1331 if (pl011_dma_rx_available(uap)) {
1332 if (pl011_dma_rx_trigger_dma(uap)) {
1333 dev_dbg(uap->port.dev, "could not trigger RX DMA job "
1334 "fall back to interrupt mode again\n");
1335 uap->im |= UART011_RXIM;
1336 pl011_write(uap->im, uap, REG_IMSC);
1337 } else {
1338 #ifdef CONFIG_DMA_ENGINE
1339 /* Start Rx DMA poll */
1340 if (uap->dmarx.poll_rate) {
1341 uap->dmarx.last_jiffies = jiffies;
1342 uap->dmarx.last_residue = PL011_DMA_BUFFER_SIZE;
1343 mod_timer(&uap->dmarx.timer,
1344 jiffies +
1345 msecs_to_jiffies(uap->dmarx.poll_rate));
1346 }
1347 #endif
1348 }
1349 }
1350 spin_lock(&uap->port.lock);
1351 }
1352
1353 static bool pl011_tx_char(struct uart_amba_port *uap, unsigned char c,
1354 bool from_irq)
1355 {
1356 if (unlikely(!from_irq) &&
1357 pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
1358 return false; /* unable to transmit character */
1359
1360 pl011_write(c, uap, REG_DR);
1361 uap->port.icount.tx++;
1362
1363 return true;
1364 }
1365
1366 static void pl011_tx_chars(struct uart_amba_port *uap, bool from_irq)
1367 {
1368 struct circ_buf *xmit = &uap->port.state->xmit;
1369 int count = uap->fifosize >> 1;
1370
1371 if (uap->port.x_char) {
1372 if (!pl011_tx_char(uap, uap->port.x_char, from_irq))
1373 return;
1374 uap->port.x_char = 0;
1375 --count;
1376 }
1377 if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
1378 pl011_stop_tx(&uap->port);
1379 return;
1380 }
1381
1382 /* If we are using DMA mode, try to send some characters. */
1383 if (pl011_dma_tx_irq(uap))
1384 return;
1385
1386 do {
1387 if (likely(from_irq) && count-- == 0)
1388 break;
1389
1390 if (!pl011_tx_char(uap, xmit->buf[xmit->tail], from_irq))
1391 break;
1392
1393 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
1394 } while (!uart_circ_empty(xmit));
1395
1396 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1397 uart_write_wakeup(&uap->port);
1398
1399 if (uart_circ_empty(xmit))
1400 pl011_stop_tx(&uap->port);
1401 }
1402
1403 static void pl011_modem_status(struct uart_amba_port *uap)
1404 {
1405 unsigned int status, delta;
1406
1407 status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY;
1408
1409 delta = status ^ uap->old_status;
1410 uap->old_status = status;
1411
1412 if (!delta)
1413 return;
1414
1415 if (delta & UART01x_FR_DCD)
1416 uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
1417
1418 if (delta & UART01x_FR_DSR)
1419 uap->port.icount.dsr++;
1420
1421 if (delta & UART01x_FR_CTS)
1422 uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
1423
1424 wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
1425 }
1426
1427 static void check_apply_cts_event_workaround(struct uart_amba_port *uap)
1428 {
1429 unsigned int dummy_read;
1430
1431 if (!uap->vendor->cts_event_workaround)
1432 return;
1433
1434 /* workaround to make sure that all bits are unlocked.. */
1435 pl011_write(0x00, uap, REG_ICR);
1436
1437 /*
1438 * WA: introduce 26ns(1 uart clk) delay before W1C;
1439 * single apb access will incur 2 pclk(133.12Mhz) delay,
1440 * so add 2 dummy reads
1441 */
1442 dummy_read = pl011_read(uap, REG_ICR);
1443 dummy_read = pl011_read(uap, REG_ICR);
1444 }
1445
1446 static irqreturn_t pl011_int(int irq, void *dev_id)
1447 {
1448 struct uart_amba_port *uap = dev_id;
1449 unsigned long flags;
1450 unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
1451 u16 imsc;
1452 int handled = 0;
1453
1454 spin_lock_irqsave(&uap->port.lock, flags);
1455 imsc = pl011_read(uap, REG_IMSC);
1456 status = pl011_read(uap, REG_RIS) & imsc;
1457 if (status) {
1458 do {
1459 check_apply_cts_event_workaround(uap);
1460
1461 pl011_write(status & ~(UART011_TXIS|UART011_RTIS|
1462 UART011_RXIS),
1463 uap, REG_ICR);
1464
1465 if (status & (UART011_RTIS|UART011_RXIS)) {
1466 if (pl011_dma_rx_running(uap))
1467 pl011_dma_rx_irq(uap);
1468 else
1469 pl011_rx_chars(uap);
1470 }
1471 if (status & (UART011_DSRMIS|UART011_DCDMIS|
1472 UART011_CTSMIS|UART011_RIMIS))
1473 pl011_modem_status(uap);
1474 if (status & UART011_TXIS)
1475 pl011_tx_chars(uap, true);
1476
1477 if (pass_counter-- == 0)
1478 break;
1479
1480 status = pl011_read(uap, REG_RIS) & imsc;
1481 } while (status != 0);
1482 handled = 1;
1483 }
1484
1485 spin_unlock_irqrestore(&uap->port.lock, flags);
1486
1487 return IRQ_RETVAL(handled);
1488 }
1489
1490 static unsigned int pl011_tx_empty(struct uart_port *port)
1491 {
1492 struct uart_amba_port *uap =
1493 container_of(port, struct uart_amba_port, port);
1494 unsigned int status = pl011_read(uap, REG_FR);
1495 return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
1496 }
1497
1498 static unsigned int pl011_get_mctrl(struct uart_port *port)
1499 {
1500 struct uart_amba_port *uap =
1501 container_of(port, struct uart_amba_port, port);
1502 unsigned int result = 0;
1503 unsigned int status = pl011_read(uap, REG_FR);
1504
1505 #define TIOCMBIT(uartbit, tiocmbit) \
1506 if (status & uartbit) \
1507 result |= tiocmbit
1508
1509 TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
1510 TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
1511 TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
1512 TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
1513 #undef TIOCMBIT
1514 return result;
1515 }
1516
1517 static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
1518 {
1519 struct uart_amba_port *uap =
1520 container_of(port, struct uart_amba_port, port);
1521 unsigned int cr;
1522
1523 cr = pl011_read(uap, REG_CR);
1524
1525 #define TIOCMBIT(tiocmbit, uartbit) \
1526 if (mctrl & tiocmbit) \
1527 cr |= uartbit; \
1528 else \
1529 cr &= ~uartbit
1530
1531 TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
1532 TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
1533 TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
1534 TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
1535 TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
1536
1537 if (uap->autorts) {
1538 /* We need to disable auto-RTS if we want to turn RTS off */
1539 TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
1540 }
1541 #undef TIOCMBIT
1542
1543 pl011_write(cr, uap, REG_CR);
1544 }
1545
1546 static void pl011_break_ctl(struct uart_port *port, int break_state)
1547 {
1548 struct uart_amba_port *uap =
1549 container_of(port, struct uart_amba_port, port);
1550 unsigned long flags;
1551 unsigned int lcr_h;
1552
1553 spin_lock_irqsave(&uap->port.lock, flags);
1554 lcr_h = pl011_read(uap, REG_LCRH_TX);
1555 if (break_state == -1)
1556 lcr_h |= UART01x_LCRH_BRK;
1557 else
1558 lcr_h &= ~UART01x_LCRH_BRK;
1559 pl011_write(lcr_h, uap, REG_LCRH_TX);
1560 spin_unlock_irqrestore(&uap->port.lock, flags);
1561 }
1562
1563 #ifdef CONFIG_CONSOLE_POLL
1564
1565 static void pl011_quiesce_irqs(struct uart_port *port)
1566 {
1567 struct uart_amba_port *uap =
1568 container_of(port, struct uart_amba_port, port);
1569
1570 pl011_write(pl011_read(uap, REG_MIS), uap, REG_ICR);
1571 /*
1572 * There is no way to clear TXIM as this is "ready to transmit IRQ", so
1573 * we simply mask it. start_tx() will unmask it.
1574 *
1575 * Note we can race with start_tx(), and if the race happens, the
1576 * polling user might get another interrupt just after we clear it.
1577 * But it should be OK and can happen even w/o the race, e.g.
1578 * controller immediately got some new data and raised the IRQ.
1579 *
1580 * And whoever uses polling routines assumes that it manages the device
1581 * (including tx queue), so we're also fine with start_tx()'s caller
1582 * side.
1583 */
1584 pl011_write(pl011_read(uap, REG_IMSC) & ~UART011_TXIM, uap,
1585 REG_IMSC);
1586 }
1587
1588 static int pl011_get_poll_char(struct uart_port *port)
1589 {
1590 struct uart_amba_port *uap =
1591 container_of(port, struct uart_amba_port, port);
1592 unsigned int status;
1593
1594 /*
1595 * The caller might need IRQs lowered, e.g. if used with KDB NMI
1596 * debugger.
1597 */
1598 pl011_quiesce_irqs(port);
1599
1600 status = pl011_read(uap, REG_FR);
1601 if (status & UART01x_FR_RXFE)
1602 return NO_POLL_CHAR;
1603
1604 return pl011_read(uap, REG_DR);
1605 }
1606
1607 static void pl011_put_poll_char(struct uart_port *port,
1608 unsigned char ch)
1609 {
1610 struct uart_amba_port *uap =
1611 container_of(port, struct uart_amba_port, port);
1612
1613 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
1614 barrier();
1615
1616 pl011_write(ch, uap, REG_DR);
1617 }
1618
1619 #endif /* CONFIG_CONSOLE_POLL */
1620
1621 static int pl011_hwinit(struct uart_port *port)
1622 {
1623 struct uart_amba_port *uap =
1624 container_of(port, struct uart_amba_port, port);
1625 int retval;
1626
1627 /* Optionaly enable pins to be muxed in and configured */
1628 pinctrl_pm_select_default_state(port->dev);
1629
1630 /*
1631 * Try to enable the clock producer.
1632 */
1633 retval = clk_prepare_enable(uap->clk);
1634 if (retval)
1635 return retval;
1636
1637 uap->port.uartclk = clk_get_rate(uap->clk);
1638
1639 /* Clear pending error and receive interrupts */
1640 pl011_write(UART011_OEIS | UART011_BEIS | UART011_PEIS |
1641 UART011_FEIS | UART011_RTIS | UART011_RXIS,
1642 uap, REG_ICR);
1643
1644 /*
1645 * Save interrupts enable mask, and enable RX interrupts in case if
1646 * the interrupt is used for NMI entry.
1647 */
1648 uap->im = pl011_read(uap, REG_IMSC);
1649 pl011_write(UART011_RTIM | UART011_RXIM, uap, REG_IMSC);
1650
1651 if (dev_get_platdata(uap->port.dev)) {
1652 struct amba_pl011_data *plat;
1653
1654 plat = dev_get_platdata(uap->port.dev);
1655 if (plat->init)
1656 plat->init();
1657 }
1658 return 0;
1659 }
1660
1661 static bool pl011_split_lcrh(const struct uart_amba_port *uap)
1662 {
1663 return pl011_reg_to_offset(uap, REG_LCRH_RX) !=
1664 pl011_reg_to_offset(uap, REG_LCRH_TX);
1665 }
1666
1667 static void pl011_write_lcr_h(struct uart_amba_port *uap, unsigned int lcr_h)
1668 {
1669 pl011_write(lcr_h, uap, REG_LCRH_RX);
1670 if (pl011_split_lcrh(uap)) {
1671 int i;
1672 /*
1673 * Wait 10 PCLKs before writing LCRH_TX register,
1674 * to get this delay write read only register 10 times
1675 */
1676 for (i = 0; i < 10; ++i)
1677 pl011_write(0xff, uap, REG_MIS);
1678 pl011_write(lcr_h, uap, REG_LCRH_TX);
1679 }
1680 }
1681
1682 static int pl011_allocate_irq(struct uart_amba_port *uap)
1683 {
1684 pl011_write(uap->im, uap, REG_IMSC);
1685
1686 return request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
1687 }
1688
1689 /*
1690 * Enable interrupts, only timeouts when using DMA
1691 * if initial RX DMA job failed, start in interrupt mode
1692 * as well.
1693 */
1694 static void pl011_enable_interrupts(struct uart_amba_port *uap)
1695 {
1696 spin_lock_irq(&uap->port.lock);
1697
1698 /* Clear out any spuriously appearing RX interrupts */
1699 pl011_write(UART011_RTIS | UART011_RXIS, uap, REG_ICR);
1700 uap->im = UART011_RTIM;
1701 if (!pl011_dma_rx_running(uap))
1702 uap->im |= UART011_RXIM;
1703 pl011_write(uap->im, uap, REG_IMSC);
1704 spin_unlock_irq(&uap->port.lock);
1705 }
1706
1707 static int pl011_startup(struct uart_port *port)
1708 {
1709 struct uart_amba_port *uap =
1710 container_of(port, struct uart_amba_port, port);
1711 unsigned int cr;
1712 int retval;
1713
1714 retval = pl011_hwinit(port);
1715 if (retval)
1716 goto clk_dis;
1717
1718 retval = pl011_allocate_irq(uap);
1719 if (retval)
1720 goto clk_dis;
1721
1722 pl011_write(uap->vendor->ifls, uap, REG_IFLS);
1723
1724 spin_lock_irq(&uap->port.lock);
1725
1726 /* restore RTS and DTR */
1727 cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
1728 cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
1729 pl011_write(cr, uap, REG_CR);
1730
1731 spin_unlock_irq(&uap->port.lock);
1732
1733 /*
1734 * initialise the old status of the modem signals
1735 */
1736 uap->old_status = pl011_read(uap, REG_FR) & UART01x_FR_MODEM_ANY;
1737
1738 /* Startup DMA */
1739 pl011_dma_startup(uap);
1740
1741 pl011_enable_interrupts(uap);
1742
1743 return 0;
1744
1745 clk_dis:
1746 clk_disable_unprepare(uap->clk);
1747 return retval;
1748 }
1749
1750 static int sbsa_uart_startup(struct uart_port *port)
1751 {
1752 struct uart_amba_port *uap =
1753 container_of(port, struct uart_amba_port, port);
1754 int retval;
1755
1756 retval = pl011_hwinit(port);
1757 if (retval)
1758 return retval;
1759
1760 retval = pl011_allocate_irq(uap);
1761 if (retval)
1762 return retval;
1763
1764 /* The SBSA UART does not support any modem status lines. */
1765 uap->old_status = 0;
1766
1767 pl011_enable_interrupts(uap);
1768
1769 return 0;
1770 }
1771
1772 static void pl011_shutdown_channel(struct uart_amba_port *uap,
1773 unsigned int lcrh)
1774 {
1775 unsigned long val;
1776
1777 val = pl011_read(uap, lcrh);
1778 val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
1779 pl011_write(val, uap, lcrh);
1780 }
1781
1782 /*
1783 * disable the port. It should not disable RTS and DTR.
1784 * Also RTS and DTR state should be preserved to restore
1785 * it during startup().
1786 */
1787 static void pl011_disable_uart(struct uart_amba_port *uap)
1788 {
1789 unsigned int cr;
1790
1791 uap->autorts = false;
1792 spin_lock_irq(&uap->port.lock);
1793 cr = pl011_read(uap, REG_CR);
1794 uap->old_cr = cr;
1795 cr &= UART011_CR_RTS | UART011_CR_DTR;
1796 cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
1797 pl011_write(cr, uap, REG_CR);
1798 spin_unlock_irq(&uap->port.lock);
1799
1800 /*
1801 * disable break condition and fifos
1802 */
1803 pl011_shutdown_channel(uap, REG_LCRH_RX);
1804 if (pl011_split_lcrh(uap))
1805 pl011_shutdown_channel(uap, REG_LCRH_TX);
1806 }
1807
1808 static void pl011_disable_interrupts(struct uart_amba_port *uap)
1809 {
1810 spin_lock_irq(&uap->port.lock);
1811
1812 /* mask all interrupts and clear all pending ones */
1813 uap->im = 0;
1814 pl011_write(uap->im, uap, REG_IMSC);
1815 pl011_write(0xffff, uap, REG_ICR);
1816
1817 spin_unlock_irq(&uap->port.lock);
1818 }
1819
1820 static void pl011_shutdown(struct uart_port *port)
1821 {
1822 struct uart_amba_port *uap =
1823 container_of(port, struct uart_amba_port, port);
1824
1825 pl011_disable_interrupts(uap);
1826
1827 pl011_dma_shutdown(uap);
1828
1829 free_irq(uap->port.irq, uap);
1830
1831 pl011_disable_uart(uap);
1832
1833 /*
1834 * Shut down the clock producer
1835 */
1836 clk_disable_unprepare(uap->clk);
1837 /* Optionally let pins go into sleep states */
1838 pinctrl_pm_select_sleep_state(port->dev);
1839
1840 if (dev_get_platdata(uap->port.dev)) {
1841 struct amba_pl011_data *plat;
1842
1843 plat = dev_get_platdata(uap->port.dev);
1844 if (plat->exit)
1845 plat->exit();
1846 }
1847
1848 if (uap->port.ops->flush_buffer)
1849 uap->port.ops->flush_buffer(port);
1850 }
1851
1852 static void sbsa_uart_shutdown(struct uart_port *port)
1853 {
1854 struct uart_amba_port *uap =
1855 container_of(port, struct uart_amba_port, port);
1856
1857 pl011_disable_interrupts(uap);
1858
1859 free_irq(uap->port.irq, uap);
1860
1861 if (uap->port.ops->flush_buffer)
1862 uap->port.ops->flush_buffer(port);
1863 }
1864
1865 static void
1866 pl011_setup_status_masks(struct uart_port *port, struct ktermios *termios)
1867 {
1868 port->read_status_mask = UART011_DR_OE | 255;
1869 if (termios->c_iflag & INPCK)
1870 port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
1871 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
1872 port->read_status_mask |= UART011_DR_BE;
1873
1874 /*
1875 * Characters to ignore
1876 */
1877 port->ignore_status_mask = 0;
1878 if (termios->c_iflag & IGNPAR)
1879 port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
1880 if (termios->c_iflag & IGNBRK) {
1881 port->ignore_status_mask |= UART011_DR_BE;
1882 /*
1883 * If we're ignoring parity and break indicators,
1884 * ignore overruns too (for real raw support).
1885 */
1886 if (termios->c_iflag & IGNPAR)
1887 port->ignore_status_mask |= UART011_DR_OE;
1888 }
1889
1890 /*
1891 * Ignore all characters if CREAD is not set.
1892 */
1893 if ((termios->c_cflag & CREAD) == 0)
1894 port->ignore_status_mask |= UART_DUMMY_DR_RX;
1895 }
1896
1897 static void
1898 pl011_set_termios(struct uart_port *port, struct ktermios *termios,
1899 struct ktermios *old)
1900 {
1901 struct uart_amba_port *uap =
1902 container_of(port, struct uart_amba_port, port);
1903 unsigned int lcr_h, old_cr;
1904 unsigned long flags;
1905 unsigned int baud, quot, clkdiv;
1906
1907 if (uap->vendor->oversampling)
1908 clkdiv = 8;
1909 else
1910 clkdiv = 16;
1911
1912 /*
1913 * Ask the core to calculate the divisor for us.
1914 */
1915 baud = uart_get_baud_rate(port, termios, old, 0,
1916 port->uartclk / clkdiv);
1917 #ifdef CONFIG_DMA_ENGINE
1918 /*
1919 * Adjust RX DMA polling rate with baud rate if not specified.
1920 */
1921 if (uap->dmarx.auto_poll_rate)
1922 uap->dmarx.poll_rate = DIV_ROUND_UP(10000000, baud);
1923 #endif
1924
1925 if (baud > port->uartclk/16)
1926 quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
1927 else
1928 quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
1929
1930 switch (termios->c_cflag & CSIZE) {
1931 case CS5:
1932 lcr_h = UART01x_LCRH_WLEN_5;
1933 break;
1934 case CS6:
1935 lcr_h = UART01x_LCRH_WLEN_6;
1936 break;
1937 case CS7:
1938 lcr_h = UART01x_LCRH_WLEN_7;
1939 break;
1940 default: // CS8
1941 lcr_h = UART01x_LCRH_WLEN_8;
1942 break;
1943 }
1944 if (termios->c_cflag & CSTOPB)
1945 lcr_h |= UART01x_LCRH_STP2;
1946 if (termios->c_cflag & PARENB) {
1947 lcr_h |= UART01x_LCRH_PEN;
1948 if (!(termios->c_cflag & PARODD))
1949 lcr_h |= UART01x_LCRH_EPS;
1950 }
1951 if (uap->fifosize > 1)
1952 lcr_h |= UART01x_LCRH_FEN;
1953
1954 spin_lock_irqsave(&port->lock, flags);
1955
1956 /*
1957 * Update the per-port timeout.
1958 */
1959 uart_update_timeout(port, termios->c_cflag, baud);
1960
1961 pl011_setup_status_masks(port, termios);
1962
1963 if (UART_ENABLE_MS(port, termios->c_cflag))
1964 pl011_enable_ms(port);
1965
1966 /* first, disable everything */
1967 old_cr = pl011_read(uap, REG_CR);
1968 pl011_write(0, uap, REG_CR);
1969
1970 if (termios->c_cflag & CRTSCTS) {
1971 if (old_cr & UART011_CR_RTS)
1972 old_cr |= UART011_CR_RTSEN;
1973
1974 old_cr |= UART011_CR_CTSEN;
1975 uap->autorts = true;
1976 } else {
1977 old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
1978 uap->autorts = false;
1979 }
1980
1981 if (uap->vendor->oversampling) {
1982 if (baud > port->uartclk / 16)
1983 old_cr |= ST_UART011_CR_OVSFACT;
1984 else
1985 old_cr &= ~ST_UART011_CR_OVSFACT;
1986 }
1987
1988 /*
1989 * Workaround for the ST Micro oversampling variants to
1990 * increase the bitrate slightly, by lowering the divisor,
1991 * to avoid delayed sampling of start bit at high speeds,
1992 * else we see data corruption.
1993 */
1994 if (uap->vendor->oversampling) {
1995 if ((baud >= 3000000) && (baud < 3250000) && (quot > 1))
1996 quot -= 1;
1997 else if ((baud > 3250000) && (quot > 2))
1998 quot -= 2;
1999 }
2000 /* Set baud rate */
2001 pl011_write(quot & 0x3f, uap, REG_FBRD);
2002 pl011_write(quot >> 6, uap, REG_IBRD);
2003
2004 /*
2005 * ----------v----------v----------v----------v-----
2006 * NOTE: REG_LCRH_TX and REG_LCRH_RX MUST BE WRITTEN AFTER
2007 * REG_FBRD & REG_IBRD.
2008 * ----------^----------^----------^----------^-----
2009 */
2010 pl011_write_lcr_h(uap, lcr_h);
2011 pl011_write(old_cr, uap, REG_CR);
2012
2013 spin_unlock_irqrestore(&port->lock, flags);
2014 }
2015
2016 static void
2017 sbsa_uart_set_termios(struct uart_port *port, struct ktermios *termios,
2018 struct ktermios *old)
2019 {
2020 struct uart_amba_port *uap =
2021 container_of(port, struct uart_amba_port, port);
2022 unsigned long flags;
2023
2024 tty_termios_encode_baud_rate(termios, uap->fixed_baud, uap->fixed_baud);
2025
2026 /* The SBSA UART only supports 8n1 without hardware flow control. */
2027 termios->c_cflag &= ~(CSIZE | CSTOPB | PARENB | PARODD);
2028 termios->c_cflag &= ~(CMSPAR | CRTSCTS);
2029 termios->c_cflag |= CS8 | CLOCAL;
2030
2031 spin_lock_irqsave(&port->lock, flags);
2032 uart_update_timeout(port, CS8, uap->fixed_baud);
2033 pl011_setup_status_masks(port, termios);
2034 spin_unlock_irqrestore(&port->lock, flags);
2035 }
2036
2037 static const char *pl011_type(struct uart_port *port)
2038 {
2039 struct uart_amba_port *uap =
2040 container_of(port, struct uart_amba_port, port);
2041 return uap->port.type == PORT_AMBA ? uap->type : NULL;
2042 }
2043
2044 /*
2045 * Release the memory region(s) being used by 'port'
2046 */
2047 static void pl011_release_port(struct uart_port *port)
2048 {
2049 release_mem_region(port->mapbase, SZ_4K);
2050 }
2051
2052 /*
2053 * Request the memory region(s) being used by 'port'
2054 */
2055 static int pl011_request_port(struct uart_port *port)
2056 {
2057 return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
2058 != NULL ? 0 : -EBUSY;
2059 }
2060
2061 /*
2062 * Configure/autoconfigure the port.
2063 */
2064 static void pl011_config_port(struct uart_port *port, int flags)
2065 {
2066 if (flags & UART_CONFIG_TYPE) {
2067 port->type = PORT_AMBA;
2068 pl011_request_port(port);
2069 }
2070 }
2071
2072 /*
2073 * verify the new serial_struct (for TIOCSSERIAL).
2074 */
2075 static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
2076 {
2077 int ret = 0;
2078 if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
2079 ret = -EINVAL;
2080 if (ser->irq < 0 || ser->irq >= nr_irqs)
2081 ret = -EINVAL;
2082 if (ser->baud_base < 9600)
2083 ret = -EINVAL;
2084 return ret;
2085 }
2086
2087 static struct uart_ops amba_pl011_pops = {
2088 .tx_empty = pl011_tx_empty,
2089 .set_mctrl = pl011_set_mctrl,
2090 .get_mctrl = pl011_get_mctrl,
2091 .stop_tx = pl011_stop_tx,
2092 .start_tx = pl011_start_tx,
2093 .stop_rx = pl011_stop_rx,
2094 .enable_ms = pl011_enable_ms,
2095 .break_ctl = pl011_break_ctl,
2096 .startup = pl011_startup,
2097 .shutdown = pl011_shutdown,
2098 .flush_buffer = pl011_dma_flush_buffer,
2099 .set_termios = pl011_set_termios,
2100 .type = pl011_type,
2101 .release_port = pl011_release_port,
2102 .request_port = pl011_request_port,
2103 .config_port = pl011_config_port,
2104 .verify_port = pl011_verify_port,
2105 #ifdef CONFIG_CONSOLE_POLL
2106 .poll_init = pl011_hwinit,
2107 .poll_get_char = pl011_get_poll_char,
2108 .poll_put_char = pl011_put_poll_char,
2109 #endif
2110 };
2111
2112 static void sbsa_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
2113 {
2114 }
2115
2116 static unsigned int sbsa_uart_get_mctrl(struct uart_port *port)
2117 {
2118 return 0;
2119 }
2120
2121 static const struct uart_ops sbsa_uart_pops = {
2122 .tx_empty = pl011_tx_empty,
2123 .set_mctrl = sbsa_uart_set_mctrl,
2124 .get_mctrl = sbsa_uart_get_mctrl,
2125 .stop_tx = pl011_stop_tx,
2126 .start_tx = pl011_start_tx,
2127 .stop_rx = pl011_stop_rx,
2128 .startup = sbsa_uart_startup,
2129 .shutdown = sbsa_uart_shutdown,
2130 .set_termios = sbsa_uart_set_termios,
2131 .type = pl011_type,
2132 .release_port = pl011_release_port,
2133 .request_port = pl011_request_port,
2134 .config_port = pl011_config_port,
2135 .verify_port = pl011_verify_port,
2136 #ifdef CONFIG_CONSOLE_POLL
2137 .poll_init = pl011_hwinit,
2138 .poll_get_char = pl011_get_poll_char,
2139 .poll_put_char = pl011_put_poll_char,
2140 #endif
2141 };
2142
2143 static struct uart_amba_port *amba_ports[UART_NR];
2144
2145 #ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
2146
2147 static void pl011_console_putchar(struct uart_port *port, int ch)
2148 {
2149 struct uart_amba_port *uap =
2150 container_of(port, struct uart_amba_port, port);
2151
2152 while (pl011_read(uap, REG_FR) & UART01x_FR_TXFF)
2153 barrier();
2154 pl011_write(ch, uap, REG_DR);
2155 }
2156
2157 static void
2158 pl011_console_write(struct console *co, const char *s, unsigned int count)
2159 {
2160 struct uart_amba_port *uap = amba_ports[co->index];
2161 unsigned int status, old_cr = 0, new_cr;
2162 unsigned long flags;
2163 int locked = 1;
2164
2165 clk_enable(uap->clk);
2166
2167 local_irq_save(flags);
2168 if (uap->port.sysrq)
2169 locked = 0;
2170 else if (oops_in_progress)
2171 locked = spin_trylock(&uap->port.lock);
2172 else
2173 spin_lock(&uap->port.lock);
2174
2175 /*
2176 * First save the CR then disable the interrupts
2177 */
2178 if (!uap->vendor->always_enabled) {
2179 old_cr = pl011_read(uap, REG_CR);
2180 new_cr = old_cr & ~UART011_CR_CTSEN;
2181 new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
2182 pl011_write(new_cr, uap, REG_CR);
2183 }
2184
2185 uart_console_write(&uap->port, s, count, pl011_console_putchar);
2186
2187 /*
2188 * Finally, wait for transmitter to become empty
2189 * and restore the TCR
2190 */
2191 do {
2192 status = pl011_read(uap, REG_FR);
2193 } while (status & UART01x_FR_BUSY);
2194 if (!uap->vendor->always_enabled)
2195 pl011_write(old_cr, uap, REG_CR);
2196
2197 if (locked)
2198 spin_unlock(&uap->port.lock);
2199 local_irq_restore(flags);
2200
2201 clk_disable(uap->clk);
2202 }
2203
2204 static void __init
2205 pl011_console_get_options(struct uart_amba_port *uap, int *baud,
2206 int *parity, int *bits)
2207 {
2208 if (pl011_read(uap, REG_CR) & UART01x_CR_UARTEN) {
2209 unsigned int lcr_h, ibrd, fbrd;
2210
2211 lcr_h = pl011_read(uap, REG_LCRH_TX);
2212
2213 *parity = 'n';
2214 if (lcr_h & UART01x_LCRH_PEN) {
2215 if (lcr_h & UART01x_LCRH_EPS)
2216 *parity = 'e';
2217 else
2218 *parity = 'o';
2219 }
2220
2221 if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
2222 *bits = 7;
2223 else
2224 *bits = 8;
2225
2226 ibrd = pl011_read(uap, REG_IBRD);
2227 fbrd = pl011_read(uap, REG_FBRD);
2228
2229 *baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
2230
2231 if (uap->vendor->oversampling) {
2232 if (pl011_read(uap, REG_CR)
2233 & ST_UART011_CR_OVSFACT)
2234 *baud *= 2;
2235 }
2236 }
2237 }
2238
2239 static int __init pl011_console_setup(struct console *co, char *options)
2240 {
2241 struct uart_amba_port *uap;
2242 int baud = 38400;
2243 int bits = 8;
2244 int parity = 'n';
2245 int flow = 'n';
2246 int ret;
2247
2248 /*
2249 * Check whether an invalid uart number has been specified, and
2250 * if so, search for the first available port that does have
2251 * console support.
2252 */
2253 if (co->index >= UART_NR)
2254 co->index = 0;
2255 uap = amba_ports[co->index];
2256 if (!uap)
2257 return -ENODEV;
2258
2259 /* Allow pins to be muxed in and configured */
2260 pinctrl_pm_select_default_state(uap->port.dev);
2261
2262 ret = clk_prepare(uap->clk);
2263 if (ret)
2264 return ret;
2265
2266 if (dev_get_platdata(uap->port.dev)) {
2267 struct amba_pl011_data *plat;
2268
2269 plat = dev_get_platdata(uap->port.dev);
2270 if (plat->init)
2271 plat->init();
2272 }
2273
2274 uap->port.uartclk = clk_get_rate(uap->clk);
2275
2276 if (uap->vendor->fixed_options) {
2277 baud = uap->fixed_baud;
2278 } else {
2279 if (options)
2280 uart_parse_options(options,
2281 &baud, &parity, &bits, &flow);
2282 else
2283 pl011_console_get_options(uap, &baud, &parity, &bits);
2284 }
2285
2286 return uart_set_options(&uap->port, co, baud, parity, bits, flow);
2287 }
2288
2289 static struct uart_driver amba_reg;
2290 static struct console amba_console = {
2291 .name = "ttyAMA",
2292 .write = pl011_console_write,
2293 .device = uart_console_device,
2294 .setup = pl011_console_setup,
2295 .flags = CON_PRINTBUFFER,
2296 .index = -1,
2297 .data = &amba_reg,
2298 };
2299
2300 #define AMBA_CONSOLE (&amba_console)
2301
2302 static void pl011_putc(struct uart_port *port, int c)
2303 {
2304 while (readl(port->membase + REG_FR) & UART01x_FR_TXFF)
2305 ;
2306 writeb(c, port->membase + REG_DR);
2307 while (readl(port->membase + REG_FR) & UART01x_FR_BUSY)
2308 ;
2309 }
2310
2311 static void pl011_early_write(struct console *con, const char *s, unsigned n)
2312 {
2313 struct earlycon_device *dev = con->data;
2314
2315 uart_console_write(&dev->port, s, n, pl011_putc);
2316 }
2317
2318 static int __init pl011_early_console_setup(struct earlycon_device *device,
2319 const char *opt)
2320 {
2321 if (!device->port.membase)
2322 return -ENODEV;
2323
2324 device->con->write = pl011_early_write;
2325 return 0;
2326 }
2327 EARLYCON_DECLARE(pl011, pl011_early_console_setup);
2328 OF_EARLYCON_DECLARE(pl011, "arm,pl011", pl011_early_console_setup);
2329
2330 #else
2331 #define AMBA_CONSOLE NULL
2332 #endif
2333
2334 static struct uart_driver amba_reg = {
2335 .owner = THIS_MODULE,
2336 .driver_name = "ttyAMA",
2337 .dev_name = "ttyAMA",
2338 .major = SERIAL_AMBA_MAJOR,
2339 .minor = SERIAL_AMBA_MINOR,
2340 .nr = UART_NR,
2341 .cons = AMBA_CONSOLE,
2342 };
2343
2344 static int pl011_probe_dt_alias(int index, struct device *dev)
2345 {
2346 struct device_node *np;
2347 static bool seen_dev_with_alias = false;
2348 static bool seen_dev_without_alias = false;
2349 int ret = index;
2350
2351 if (!IS_ENABLED(CONFIG_OF))
2352 return ret;
2353
2354 np = dev->of_node;
2355 if (!np)
2356 return ret;
2357
2358 ret = of_alias_get_id(np, "serial");
2359 if (IS_ERR_VALUE(ret)) {
2360 seen_dev_without_alias = true;
2361 ret = index;
2362 } else {
2363 seen_dev_with_alias = true;
2364 if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) {
2365 dev_warn(dev, "requested serial port %d not available.\n", ret);
2366 ret = index;
2367 }
2368 }
2369
2370 if (seen_dev_with_alias && seen_dev_without_alias)
2371 dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n");
2372
2373 return ret;
2374 }
2375
2376 /* unregisters the driver also if no more ports are left */
2377 static void pl011_unregister_port(struct uart_amba_port *uap)
2378 {
2379 int i;
2380 bool busy = false;
2381
2382 for (i = 0; i < ARRAY_SIZE(amba_ports); i++) {
2383 if (amba_ports[i] == uap)
2384 amba_ports[i] = NULL;
2385 else if (amba_ports[i])
2386 busy = true;
2387 }
2388 pl011_dma_remove(uap);
2389 if (!busy)
2390 uart_unregister_driver(&amba_reg);
2391 }
2392
2393 static int pl011_find_free_port(void)
2394 {
2395 int i;
2396
2397 for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
2398 if (amba_ports[i] == NULL)
2399 return i;
2400
2401 return -EBUSY;
2402 }
2403
2404 static int pl011_setup_port(struct device *dev, struct uart_amba_port *uap,
2405 struct resource *mmiobase, int index)
2406 {
2407 void __iomem *base;
2408
2409 base = devm_ioremap_resource(dev, mmiobase);
2410 if (IS_ERR(base))
2411 return PTR_ERR(base);
2412
2413 index = pl011_probe_dt_alias(index, dev);
2414
2415 uap->old_cr = 0;
2416 uap->port.dev = dev;
2417 uap->port.mapbase = mmiobase->start;
2418 uap->port.membase = base;
2419 uap->port.iotype = UPIO_MEM;
2420 uap->port.fifosize = uap->fifosize;
2421 uap->port.flags = UPF_BOOT_AUTOCONF;
2422 uap->port.line = index;
2423
2424 amba_ports[index] = uap;
2425
2426 return 0;
2427 }
2428
2429 static int pl011_register_port(struct uart_amba_port *uap)
2430 {
2431 int ret;
2432
2433 /* Ensure interrupts from this UART are masked and cleared */
2434 pl011_write(0, uap, REG_IMSC);
2435 pl011_write(0xffff, uap, REG_ICR);
2436
2437 if (!amba_reg.state) {
2438 ret = uart_register_driver(&amba_reg);
2439 if (ret < 0) {
2440 dev_err(uap->port.dev,
2441 "Failed to register AMBA-PL011 driver\n");
2442 return ret;
2443 }
2444 }
2445
2446 ret = uart_add_one_port(&amba_reg, &uap->port);
2447 if (ret)
2448 pl011_unregister_port(uap);
2449
2450 return ret;
2451 }
2452
2453 static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
2454 {
2455 struct uart_amba_port *uap;
2456 struct vendor_data *vendor = id->data;
2457 int portnr, ret;
2458
2459 portnr = pl011_find_free_port();
2460 if (portnr < 0)
2461 return portnr;
2462
2463 uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
2464 GFP_KERNEL);
2465 if (!uap)
2466 return -ENOMEM;
2467
2468 uap->clk = devm_clk_get(&dev->dev, NULL);
2469 if (IS_ERR(uap->clk))
2470 return PTR_ERR(uap->clk);
2471
2472 uap->reg_offset = vendor->reg_offset;
2473 uap->access_32b = vendor->access_32b;
2474 uap->vendor = vendor;
2475 uap->fifosize = vendor->get_fifosize(dev);
2476 uap->port.irq = dev->irq[0];
2477 uap->port.ops = &amba_pl011_pops;
2478
2479 snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
2480
2481 ret = pl011_setup_port(&dev->dev, uap, &dev->res, portnr);
2482 if (ret)
2483 return ret;
2484
2485 amba_set_drvdata(dev, uap);
2486
2487 return pl011_register_port(uap);
2488 }
2489
2490 static int pl011_remove(struct amba_device *dev)
2491 {
2492 struct uart_amba_port *uap = amba_get_drvdata(dev);
2493
2494 uart_remove_one_port(&amba_reg, &uap->port);
2495 pl011_unregister_port(uap);
2496 return 0;
2497 }
2498
2499 #ifdef CONFIG_PM_SLEEP
2500 static int pl011_suspend(struct device *dev)
2501 {
2502 struct uart_amba_port *uap = dev_get_drvdata(dev);
2503
2504 if (!uap)
2505 return -EINVAL;
2506
2507 return uart_suspend_port(&amba_reg, &uap->port);
2508 }
2509
2510 static int pl011_resume(struct device *dev)
2511 {
2512 struct uart_amba_port *uap = dev_get_drvdata(dev);
2513
2514 if (!uap)
2515 return -EINVAL;
2516
2517 return uart_resume_port(&amba_reg, &uap->port);
2518 }
2519 #endif
2520
2521 static SIMPLE_DEV_PM_OPS(pl011_dev_pm_ops, pl011_suspend, pl011_resume);
2522
2523 static int sbsa_uart_probe(struct platform_device *pdev)
2524 {
2525 struct uart_amba_port *uap;
2526 struct resource *r;
2527 int portnr, ret;
2528 int baudrate;
2529
2530 /*
2531 * Check the mandatory baud rate parameter in the DT node early
2532 * so that we can easily exit with the error.
2533 */
2534 if (pdev->dev.of_node) {
2535 struct device_node *np = pdev->dev.of_node;
2536
2537 ret = of_property_read_u32(np, "current-speed", &baudrate);
2538 if (ret)
2539 return ret;
2540 } else {
2541 baudrate = 115200;
2542 }
2543
2544 portnr = pl011_find_free_port();
2545 if (portnr < 0)
2546 return portnr;
2547
2548 uap = devm_kzalloc(&pdev->dev, sizeof(struct uart_amba_port),
2549 GFP_KERNEL);
2550 if (!uap)
2551 return -ENOMEM;
2552
2553 uap->reg_offset = vendor_sbsa.reg_offset;
2554 uap->access_32b = vendor_sbsa.access_32b;
2555 uap->vendor = &vendor_sbsa;
2556 uap->fifosize = 32;
2557 uap->port.irq = platform_get_irq(pdev, 0);
2558 uap->port.ops = &sbsa_uart_pops;
2559 uap->fixed_baud = baudrate;
2560
2561 snprintf(uap->type, sizeof(uap->type), "SBSA");
2562
2563 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
2564
2565 ret = pl011_setup_port(&pdev->dev, uap, r, portnr);
2566 if (ret)
2567 return ret;
2568
2569 platform_set_drvdata(pdev, uap);
2570
2571 return pl011_register_port(uap);
2572 }
2573
2574 static int sbsa_uart_remove(struct platform_device *pdev)
2575 {
2576 struct uart_amba_port *uap = platform_get_drvdata(pdev);
2577
2578 uart_remove_one_port(&amba_reg, &uap->port);
2579 pl011_unregister_port(uap);
2580 return 0;
2581 }
2582
2583 static const struct of_device_id sbsa_uart_of_match[] = {
2584 { .compatible = "arm,sbsa-uart", },
2585 {},
2586 };
2587 MODULE_DEVICE_TABLE(of, sbsa_uart_of_match);
2588
2589 static const struct acpi_device_id sbsa_uart_acpi_match[] = {
2590 { "ARMH0011", 0 },
2591 {},
2592 };
2593 MODULE_DEVICE_TABLE(acpi, sbsa_uart_acpi_match);
2594
2595 static struct platform_driver arm_sbsa_uart_platform_driver = {
2596 .probe = sbsa_uart_probe,
2597 .remove = sbsa_uart_remove,
2598 .driver = {
2599 .name = "sbsa-uart",
2600 .of_match_table = of_match_ptr(sbsa_uart_of_match),
2601 .acpi_match_table = ACPI_PTR(sbsa_uart_acpi_match),
2602 },
2603 };
2604
2605 static struct amba_id pl011_ids[] = {
2606 {
2607 .id = 0x00041011,
2608 .mask = 0x000fffff,
2609 .data = &vendor_arm,
2610 },
2611 {
2612 .id = 0x00380802,
2613 .mask = 0x00ffffff,
2614 .data = &vendor_st,
2615 },
2616 { 0, 0 },
2617 };
2618
2619 MODULE_DEVICE_TABLE(amba, pl011_ids);
2620
2621 static struct amba_driver pl011_driver = {
2622 .drv = {
2623 .name = "uart-pl011",
2624 .pm = &pl011_dev_pm_ops,
2625 },
2626 .id_table = pl011_ids,
2627 .probe = pl011_probe,
2628 .remove = pl011_remove,
2629 };
2630
2631 static int __init pl011_init(void)
2632 {
2633 printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
2634
2635 if (platform_driver_register(&arm_sbsa_uart_platform_driver))
2636 pr_warn("could not register SBSA UART platform driver\n");
2637 return amba_driver_register(&pl011_driver);
2638 }
2639
2640 static void __exit pl011_exit(void)
2641 {
2642 platform_driver_unregister(&arm_sbsa_uart_platform_driver);
2643 amba_driver_unregister(&pl011_driver);
2644 }
2645
2646 /*
2647 * While this can be a module, if builtin it's most likely the console
2648 * So let's leave module_exit but move module_init to an earlier place
2649 */
2650 arch_initcall(pl011_init);
2651 module_exit(pl011_exit);
2652
2653 MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
2654 MODULE_DESCRIPTION("ARM AMBA serial port driver");
2655 MODULE_LICENSE("GPL");
Linux kernel - Deliverables
This page took 0.124324 seconds and 5 git commands to generate.