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Merge branch 'turbostat' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux
[mirror_ubuntu-zesty-kernel.git] / drivers / tty / serial / pic32_uart.c
1 /*
2 * PIC32 Integrated Serial Driver.
3 *
4 * Copyright (C) 2015 Microchip Technology, Inc.
5 *
6 * Authors:
7 * Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>
8 *
9 * Licensed under GPLv2 or later.
10 */
11
12 #include <linux/kernel.h>
13 #include <linux/platform_device.h>
14 #include <linux/of.h>
15 #include <linux/of_device.h>
16 #include <linux/of_irq.h>
17 #include <linux/of_gpio.h>
18 #include <linux/init.h>
19 #include <linux/module.h>
20 #include <linux/slab.h>
21 #include <linux/console.h>
22 #include <linux/clk.h>
23 #include <linux/tty.h>
24 #include <linux/tty_flip.h>
25 #include <linux/serial_core.h>
26 #include <linux/delay.h>
27
28 #include <asm/mach-pic32/pic32.h>
29 #include "pic32_uart.h"
30
31 /* UART name and device definitions */
32 #define PIC32_DEV_NAME "pic32-uart"
33 #define PIC32_MAX_UARTS 6
34 #define PIC32_SDEV_NAME "ttyPIC"
35
36 /* pic32_sport pointer for console use */
37 static struct pic32_sport *pic32_sports[PIC32_MAX_UARTS];
38
39 static inline void pic32_wait_deplete_txbuf(struct pic32_sport *sport)
40 {
41 /* wait for tx empty, otherwise chars will be lost or corrupted */
42 while (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_TRMT))
43 udelay(1);
44 }
45
46 static inline int pic32_enable_clock(struct pic32_sport *sport)
47 {
48 int ret = clk_prepare_enable(sport->clk);
49
50 if (ret)
51 return ret;
52
53 sport->ref_clk++;
54 return 0;
55 }
56
57 static inline void pic32_disable_clock(struct pic32_sport *sport)
58 {
59 sport->ref_clk--;
60 clk_disable_unprepare(sport->clk);
61 }
62
63 /* serial core request to check if uart tx buffer is empty */
64 static unsigned int pic32_uart_tx_empty(struct uart_port *port)
65 {
66 struct pic32_sport *sport = to_pic32_sport(port);
67 u32 val = pic32_uart_readl(sport, PIC32_UART_STA);
68
69 return (val & PIC32_UART_STA_TRMT) ? 1 : 0;
70 }
71
72 /* serial core request to set UART outputs */
73 static void pic32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
74 {
75 struct pic32_sport *sport = to_pic32_sport(port);
76
77 /* set loopback mode */
78 if (mctrl & TIOCM_LOOP)
79 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
80 PIC32_UART_MODE_LPBK);
81 else
82 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
83 PIC32_UART_MODE_LPBK);
84 }
85
86 /* get the state of CTS input pin for this port */
87 static unsigned int get_cts_state(struct pic32_sport *sport)
88 {
89 /* read and invert UxCTS */
90 if (gpio_is_valid(sport->cts_gpio))
91 return !gpio_get_value(sport->cts_gpio);
92
93 return 1;
94 }
95
96 /* serial core request to return the state of misc UART input pins */
97 static unsigned int pic32_uart_get_mctrl(struct uart_port *port)
98 {
99 struct pic32_sport *sport = to_pic32_sport(port);
100 unsigned int mctrl = 0;
101
102 if (!sport->hw_flow_ctrl)
103 mctrl |= TIOCM_CTS;
104 else if (get_cts_state(sport))
105 mctrl |= TIOCM_CTS;
106
107 /* DSR and CD are not supported in PIC32, so return 1
108 * RI is not supported in PIC32, so return 0
109 */
110 mctrl |= TIOCM_CD;
111 mctrl |= TIOCM_DSR;
112
113 return mctrl;
114 }
115
116 /* stop tx and start tx are not called in pairs, therefore a flag indicates
117 * the status of irq to control the irq-depth.
118 */
119 static inline void pic32_uart_irqtxen(struct pic32_sport *sport, u8 en)
120 {
121 if (en && !tx_irq_enabled(sport)) {
122 enable_irq(sport->irq_tx);
123 tx_irq_enabled(sport) = 1;
124 } else if (!en && tx_irq_enabled(sport)) {
125 /* use disable_irq_nosync() and not disable_irq() to avoid self
126 * imposed deadlock by not waiting for irq handler to end,
127 * since this callback is called from interrupt context.
128 */
129 disable_irq_nosync(sport->irq_tx);
130 tx_irq_enabled(sport) = 0;
131 }
132 }
133
134 /* serial core request to disable tx ASAP (used for flow control) */
135 static void pic32_uart_stop_tx(struct uart_port *port)
136 {
137 struct pic32_sport *sport = to_pic32_sport(port);
138
139 if (!(pic32_uart_readl(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
140 return;
141
142 if (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
143 return;
144
145 /* wait for tx empty */
146 pic32_wait_deplete_txbuf(sport);
147
148 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
149 PIC32_UART_STA_UTXEN);
150 pic32_uart_irqtxen(sport, 0);
151 }
152
153 /* serial core request to (re)enable tx */
154 static void pic32_uart_start_tx(struct uart_port *port)
155 {
156 struct pic32_sport *sport = to_pic32_sport(port);
157
158 pic32_uart_irqtxen(sport, 1);
159 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA),
160 PIC32_UART_STA_UTXEN);
161 }
162
163 /* serial core request to stop rx, called before port shutdown */
164 static void pic32_uart_stop_rx(struct uart_port *port)
165 {
166 struct pic32_sport *sport = to_pic32_sport(port);
167
168 /* disable rx interrupts */
169 disable_irq(sport->irq_rx);
170
171 /* receiver Enable bit OFF */
172 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
173 PIC32_UART_STA_URXEN);
174 }
175
176 /* serial core request to start/stop emitting break char */
177 static void pic32_uart_break_ctl(struct uart_port *port, int ctl)
178 {
179 struct pic32_sport *sport = to_pic32_sport(port);
180 unsigned long flags;
181
182 spin_lock_irqsave(&port->lock, flags);
183
184 if (ctl)
185 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA),
186 PIC32_UART_STA_UTXBRK);
187 else
188 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
189 PIC32_UART_STA_UTXBRK);
190
191 spin_unlock_irqrestore(&port->lock, flags);
192 }
193
194 /* get port type in string format */
195 static const char *pic32_uart_type(struct uart_port *port)
196 {
197 return (port->type == PORT_PIC32) ? PIC32_DEV_NAME : NULL;
198 }
199
200 /* read all chars in rx fifo and send them to core */
201 static void pic32_uart_do_rx(struct uart_port *port)
202 {
203 struct pic32_sport *sport = to_pic32_sport(port);
204 struct tty_port *tty;
205 unsigned int max_count;
206
207 /* limit number of char read in interrupt, should not be
208 * higher than fifo size anyway since we're much faster than
209 * serial port
210 */
211 max_count = PIC32_UART_RX_FIFO_DEPTH;
212
213 spin_lock(&port->lock);
214
215 tty = &port->state->port;
216
217 do {
218 u32 sta_reg, c;
219 char flag;
220
221 /* get overrun/fifo empty information from status register */
222 sta_reg = pic32_uart_readl(sport, PIC32_UART_STA);
223 if (unlikely(sta_reg & PIC32_UART_STA_OERR)) {
224
225 /* fifo reset is required to clear interrupt */
226 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
227 PIC32_UART_STA_OERR);
228
229 port->icount.overrun++;
230 tty_insert_flip_char(tty, 0, TTY_OVERRUN);
231 }
232
233 /* Can at least one more character can be read? */
234 if (!(sta_reg & PIC32_UART_STA_URXDA))
235 break;
236
237 /* read the character and increment the rx counter */
238 c = pic32_uart_readl(sport, PIC32_UART_RX);
239
240 port->icount.rx++;
241 flag = TTY_NORMAL;
242 c &= 0xff;
243
244 if (unlikely((sta_reg & PIC32_UART_STA_PERR) ||
245 (sta_reg & PIC32_UART_STA_FERR))) {
246
247 /* do stats first */
248 if (sta_reg & PIC32_UART_STA_PERR)
249 port->icount.parity++;
250 if (sta_reg & PIC32_UART_STA_FERR)
251 port->icount.frame++;
252
253 /* update flag wrt read_status_mask */
254 sta_reg &= port->read_status_mask;
255
256 if (sta_reg & PIC32_UART_STA_FERR)
257 flag = TTY_FRAME;
258 if (sta_reg & PIC32_UART_STA_PERR)
259 flag = TTY_PARITY;
260 }
261
262 if (uart_handle_sysrq_char(port, c))
263 continue;
264
265 if ((sta_reg & port->ignore_status_mask) == 0)
266 tty_insert_flip_char(tty, c, flag);
267
268 } while (--max_count);
269
270 spin_unlock(&port->lock);
271
272 tty_flip_buffer_push(tty);
273 }
274
275 /* fill tx fifo with chars to send, stop when fifo is about to be full
276 * or when all chars have been sent.
277 */
278 static void pic32_uart_do_tx(struct uart_port *port)
279 {
280 struct pic32_sport *sport = to_pic32_sport(port);
281 struct circ_buf *xmit = &port->state->xmit;
282 unsigned int max_count = PIC32_UART_TX_FIFO_DEPTH;
283
284 if (port->x_char) {
285 pic32_uart_writel(sport, PIC32_UART_TX, port->x_char);
286 port->icount.tx++;
287 port->x_char = 0;
288 return;
289 }
290
291 if (uart_tx_stopped(port)) {
292 pic32_uart_stop_tx(port);
293 return;
294 }
295
296 if (uart_circ_empty(xmit))
297 goto txq_empty;
298
299 /* keep stuffing chars into uart tx buffer
300 * 1) until uart fifo is full
301 * or
302 * 2) until the circ buffer is empty
303 * (all chars have been sent)
304 * or
305 * 3) until the max count is reached
306 * (prevents lingering here for too long in certain cases)
307 */
308 while (!(PIC32_UART_STA_UTXBF &
309 pic32_uart_readl(sport, PIC32_UART_STA))) {
310 unsigned int c = xmit->buf[xmit->tail];
311
312 pic32_uart_writel(sport, PIC32_UART_TX, c);
313
314 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
315 port->icount.tx++;
316 if (uart_circ_empty(xmit))
317 break;
318 if (--max_count == 0)
319 break;
320 }
321
322 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
323 uart_write_wakeup(port);
324
325 if (uart_circ_empty(xmit))
326 goto txq_empty;
327
328 return;
329
330 txq_empty:
331 pic32_uart_irqtxen(sport, 0);
332 }
333
334 /* RX interrupt handler */
335 static irqreturn_t pic32_uart_rx_interrupt(int irq, void *dev_id)
336 {
337 struct uart_port *port = dev_id;
338
339 pic32_uart_do_rx(port);
340
341 return IRQ_HANDLED;
342 }
343
344 /* TX interrupt handler */
345 static irqreturn_t pic32_uart_tx_interrupt(int irq, void *dev_id)
346 {
347 struct uart_port *port = dev_id;
348 unsigned long flags;
349
350 spin_lock_irqsave(&port->lock, flags);
351 pic32_uart_do_tx(port);
352 spin_unlock_irqrestore(&port->lock, flags);
353
354 return IRQ_HANDLED;
355 }
356
357 /* FAULT interrupt handler */
358 static irqreturn_t pic32_uart_fault_interrupt(int irq, void *dev_id)
359 {
360 /* do nothing: pic32_uart_do_rx() handles faults. */
361 return IRQ_HANDLED;
362 }
363
364 /* enable rx & tx operation on uart */
365 static void pic32_uart_en_and_unmask(struct uart_port *port)
366 {
367 struct pic32_sport *sport = to_pic32_sport(port);
368
369 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA),
370 PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN);
371 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
372 PIC32_UART_MODE_ON);
373 }
374
375 /* disable rx & tx operation on uart */
376 static void pic32_uart_dsbl_and_mask(struct uart_port *port)
377 {
378 struct pic32_sport *sport = to_pic32_sport(port);
379
380 /* wait for tx empty, otherwise chars will be lost or corrupted */
381 pic32_wait_deplete_txbuf(sport);
382
383 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
384 PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN);
385 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
386 PIC32_UART_MODE_ON);
387 }
388
389 /* serial core request to initialize uart and start rx operation */
390 static int pic32_uart_startup(struct uart_port *port)
391 {
392 struct pic32_sport *sport = to_pic32_sport(port);
393 u32 dflt_baud = (port->uartclk / PIC32_UART_DFLT_BRATE / 16) - 1;
394 unsigned long flags;
395 int ret;
396
397 local_irq_save(flags);
398
399 ret = pic32_enable_clock(sport);
400 if (ret) {
401 local_irq_restore(flags);
402 goto out_done;
403 }
404
405 /* clear status and mode registers */
406 pic32_uart_writel(sport, PIC32_UART_MODE, 0);
407 pic32_uart_writel(sport, PIC32_UART_STA, 0);
408
409 /* disable uart and mask all interrupts */
410 pic32_uart_dsbl_and_mask(port);
411
412 /* set default baud */
413 pic32_uart_writel(sport, PIC32_UART_BRG, dflt_baud);
414
415 local_irq_restore(flags);
416
417 /* Each UART of a PIC32 has three interrupts therefore,
418 * we setup driver to register the 3 irqs for the device.
419 *
420 * For each irq request_irq() is called with interrupt disabled.
421 * And the irq is enabled as soon as we are ready to handle them.
422 */
423 tx_irq_enabled(sport) = 0;
424
425 sport->irq_fault_name = kasprintf(GFP_KERNEL, "%s%d-fault",
426 pic32_uart_type(port),
427 sport->idx);
428 if (!sport->irq_fault_name) {
429 dev_err(port->dev, "%s: kasprintf err!", __func__);
430 ret = -ENOMEM;
431 goto out_done;
432 }
433 irq_set_status_flags(sport->irq_fault, IRQ_NOAUTOEN);
434 ret = request_irq(sport->irq_fault, pic32_uart_fault_interrupt,
435 sport->irqflags_fault, sport->irq_fault_name, port);
436 if (ret) {
437 dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
438 __func__, sport->irq_fault, ret,
439 pic32_uart_type(port));
440 goto out_f;
441 }
442
443 sport->irq_rx_name = kasprintf(GFP_KERNEL, "%s%d-rx",
444 pic32_uart_type(port),
445 sport->idx);
446 if (!sport->irq_rx_name) {
447 dev_err(port->dev, "%s: kasprintf err!", __func__);
448 ret = -ENOMEM;
449 goto out_f;
450 }
451 irq_set_status_flags(sport->irq_rx, IRQ_NOAUTOEN);
452 ret = request_irq(sport->irq_rx, pic32_uart_rx_interrupt,
453 sport->irqflags_rx, sport->irq_rx_name, port);
454 if (ret) {
455 dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
456 __func__, sport->irq_rx, ret,
457 pic32_uart_type(port));
458 goto out_r;
459 }
460
461 sport->irq_tx_name = kasprintf(GFP_KERNEL, "%s%d-tx",
462 pic32_uart_type(port),
463 sport->idx);
464 if (!sport->irq_tx_name) {
465 dev_err(port->dev, "%s: kasprintf err!", __func__);
466 ret = -ENOMEM;
467 goto out_r;
468 }
469 irq_set_status_flags(sport->irq_tx, IRQ_NOAUTOEN);
470 ret = request_irq(sport->irq_tx, pic32_uart_tx_interrupt,
471 sport->irqflags_tx, sport->irq_tx_name, port);
472 if (ret) {
473 dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
474 __func__, sport->irq_tx, ret,
475 pic32_uart_type(port));
476 goto out_t;
477 }
478
479 local_irq_save(flags);
480
481 /* set rx interrupt on first receive */
482 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
483 PIC32_UART_STA_URXISEL1 | PIC32_UART_STA_URXISEL0);
484
485 /* set interrupt on empty */
486 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
487 PIC32_UART_STA_UTXISEL1);
488
489 /* enable all interrupts and eanable uart */
490 pic32_uart_en_and_unmask(port);
491
492 enable_irq(sport->irq_rx);
493
494 return 0;
495
496 out_t:
497 kfree(sport->irq_tx_name);
498 free_irq(sport->irq_tx, sport);
499 out_r:
500 kfree(sport->irq_rx_name);
501 free_irq(sport->irq_rx, sport);
502 out_f:
503 kfree(sport->irq_fault_name);
504 free_irq(sport->irq_fault, sport);
505 out_done:
506 return ret;
507 }
508
509 /* serial core request to flush & disable uart */
510 static void pic32_uart_shutdown(struct uart_port *port)
511 {
512 struct pic32_sport *sport = to_pic32_sport(port);
513 unsigned long flags;
514
515 /* disable uart */
516 spin_lock_irqsave(&port->lock, flags);
517 pic32_uart_dsbl_and_mask(port);
518 spin_unlock_irqrestore(&port->lock, flags);
519 pic32_disable_clock(sport);
520
521 /* free all 3 interrupts for this UART */
522 free_irq(sport->irq_fault, port);
523 free_irq(sport->irq_tx, port);
524 free_irq(sport->irq_rx, port);
525 }
526
527 /* serial core request to change current uart setting */
528 static void pic32_uart_set_termios(struct uart_port *port,
529 struct ktermios *new,
530 struct ktermios *old)
531 {
532 struct pic32_sport *sport = to_pic32_sport(port);
533 unsigned int baud;
534 unsigned int quot;
535 unsigned long flags;
536
537 spin_lock_irqsave(&port->lock, flags);
538
539 /* disable uart and mask all interrupts while changing speed */
540 pic32_uart_dsbl_and_mask(port);
541
542 /* stop bit options */
543 if (new->c_cflag & CSTOPB)
544 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
545 PIC32_UART_MODE_STSEL);
546 else
547 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
548 PIC32_UART_MODE_STSEL);
549
550 /* parity options */
551 if (new->c_cflag & PARENB) {
552 if (new->c_cflag & PARODD) {
553 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
554 PIC32_UART_MODE_PDSEL1);
555 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
556 PIC32_UART_MODE_PDSEL0);
557 } else {
558 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
559 PIC32_UART_MODE_PDSEL0);
560 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
561 PIC32_UART_MODE_PDSEL1);
562 }
563 } else {
564 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
565 PIC32_UART_MODE_PDSEL1 |
566 PIC32_UART_MODE_PDSEL0);
567 }
568 /* if hw flow ctrl, then the pins must be specified in device tree */
569 if ((new->c_cflag & CRTSCTS) && sport->hw_flow_ctrl) {
570 /* enable hardware flow control */
571 pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
572 PIC32_UART_MODE_UEN1);
573 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
574 PIC32_UART_MODE_UEN0);
575 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
576 PIC32_UART_MODE_RTSMD);
577 } else {
578 /* disable hardware flow control */
579 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
580 PIC32_UART_MODE_UEN1);
581 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
582 PIC32_UART_MODE_UEN0);
583 pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
584 PIC32_UART_MODE_RTSMD);
585 }
586
587 /* Always 8-bit */
588 new->c_cflag |= CS8;
589
590 /* Mark/Space parity is not supported */
591 new->c_cflag &= ~CMSPAR;
592
593 /* update baud */
594 baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
595 quot = uart_get_divisor(port, baud) - 1;
596 pic32_uart_writel(sport, PIC32_UART_BRG, quot);
597 uart_update_timeout(port, new->c_cflag, baud);
598
599 if (tty_termios_baud_rate(new))
600 tty_termios_encode_baud_rate(new, baud, baud);
601
602 /* enable uart */
603 pic32_uart_en_and_unmask(port);
604
605 spin_unlock_irqrestore(&port->lock, flags);
606 }
607
608 /* serial core request to claim uart iomem */
609 static int pic32_uart_request_port(struct uart_port *port)
610 {
611 struct platform_device *pdev = to_platform_device(port->dev);
612 struct resource *res_mem;
613
614 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
615 if (unlikely(!res_mem))
616 return -EINVAL;
617
618 if (!request_mem_region(port->mapbase, resource_size(res_mem),
619 "pic32_uart_mem"))
620 return -EBUSY;
621
622 port->membase = devm_ioremap_nocache(port->dev, port->mapbase,
623 resource_size(res_mem));
624 if (!port->membase) {
625 dev_err(port->dev, "Unable to map registers\n");
626 release_mem_region(port->mapbase, resource_size(res_mem));
627 return -ENOMEM;
628 }
629
630 return 0;
631 }
632
633 /* serial core request to release uart iomem */
634 static void pic32_uart_release_port(struct uart_port *port)
635 {
636 struct platform_device *pdev = to_platform_device(port->dev);
637 struct resource *res_mem;
638 unsigned int res_size;
639
640 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
641 if (unlikely(!res_mem))
642 return;
643 res_size = resource_size(res_mem);
644
645 release_mem_region(port->mapbase, res_size);
646 }
647
648 /* serial core request to do any port required auto-configuration */
649 static void pic32_uart_config_port(struct uart_port *port, int flags)
650 {
651 if (flags & UART_CONFIG_TYPE) {
652 if (pic32_uart_request_port(port))
653 return;
654 port->type = PORT_PIC32;
655 }
656 }
657
658 /* serial core request to check that port information in serinfo are suitable */
659 static int pic32_uart_verify_port(struct uart_port *port,
660 struct serial_struct *serinfo)
661 {
662 if (port->type != PORT_PIC32)
663 return -EINVAL;
664 if (port->irq != serinfo->irq)
665 return -EINVAL;
666 if (port->iotype != serinfo->io_type)
667 return -EINVAL;
668 if (port->mapbase != (unsigned long)serinfo->iomem_base)
669 return -EINVAL;
670
671 return 0;
672 }
673
674 /* serial core callbacks */
675 static const struct uart_ops pic32_uart_ops = {
676 .tx_empty = pic32_uart_tx_empty,
677 .get_mctrl = pic32_uart_get_mctrl,
678 .set_mctrl = pic32_uart_set_mctrl,
679 .start_tx = pic32_uart_start_tx,
680 .stop_tx = pic32_uart_stop_tx,
681 .stop_rx = pic32_uart_stop_rx,
682 .break_ctl = pic32_uart_break_ctl,
683 .startup = pic32_uart_startup,
684 .shutdown = pic32_uart_shutdown,
685 .set_termios = pic32_uart_set_termios,
686 .type = pic32_uart_type,
687 .release_port = pic32_uart_release_port,
688 .request_port = pic32_uart_request_port,
689 .config_port = pic32_uart_config_port,
690 .verify_port = pic32_uart_verify_port,
691 };
692
693 #ifdef CONFIG_SERIAL_PIC32_CONSOLE
694 /* output given char */
695 static void pic32_console_putchar(struct uart_port *port, int ch)
696 {
697 struct pic32_sport *sport = to_pic32_sport(port);
698
699 if (!(pic32_uart_readl(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
700 return;
701
702 if (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
703 return;
704
705 /* wait for tx empty */
706 pic32_wait_deplete_txbuf(sport);
707
708 pic32_uart_writel(sport, PIC32_UART_TX, ch & 0xff);
709 }
710
711 /* console core request to output given string */
712 static void pic32_console_write(struct console *co, const char *s,
713 unsigned int count)
714 {
715 struct pic32_sport *sport = pic32_sports[co->index];
716 struct uart_port *port = pic32_get_port(sport);
717
718 /* call uart helper to deal with \r\n */
719 uart_console_write(port, s, count, pic32_console_putchar);
720 }
721
722 /* console core request to setup given console, find matching uart
723 * port and setup it.
724 */
725 static int pic32_console_setup(struct console *co, char *options)
726 {
727 struct pic32_sport *sport;
728 struct uart_port *port = NULL;
729 int baud = 115200;
730 int bits = 8;
731 int parity = 'n';
732 int flow = 'n';
733 int ret = 0;
734
735 if (unlikely(co->index < 0 || co->index >= PIC32_MAX_UARTS))
736 return -ENODEV;
737
738 sport = pic32_sports[co->index];
739 if (!sport)
740 return -ENODEV;
741 port = pic32_get_port(sport);
742
743 ret = pic32_enable_clock(sport);
744 if (ret)
745 return ret;
746
747 if (options)
748 uart_parse_options(options, &baud, &parity, &bits, &flow);
749
750 return uart_set_options(port, co, baud, parity, bits, flow);
751 }
752
753 static struct uart_driver pic32_uart_driver;
754 static struct console pic32_console = {
755 .name = PIC32_SDEV_NAME,
756 .write = pic32_console_write,
757 .device = uart_console_device,
758 .setup = pic32_console_setup,
759 .flags = CON_PRINTBUFFER,
760 .index = -1,
761 .data = &pic32_uart_driver,
762 };
763 #define PIC32_SCONSOLE (&pic32_console)
764
765 static int __init pic32_console_init(void)
766 {
767 register_console(&pic32_console);
768 return 0;
769 }
770 console_initcall(pic32_console_init);
771
772 static inline bool is_pic32_console_port(struct uart_port *port)
773 {
774 return port->cons && port->cons->index == port->line;
775 }
776
777 /*
778 * Late console initialization.
779 */
780 static int __init pic32_late_console_init(void)
781 {
782 if (!(pic32_console.flags & CON_ENABLED))
783 register_console(&pic32_console);
784
785 return 0;
786 }
787
788 core_initcall(pic32_late_console_init);
789
790 #else
791 #define PIC32_SCONSOLE NULL
792 #endif
793
794 static struct uart_driver pic32_uart_driver = {
795 .owner = THIS_MODULE,
796 .driver_name = PIC32_DEV_NAME,
797 .dev_name = PIC32_SDEV_NAME,
798 .nr = PIC32_MAX_UARTS,
799 .cons = PIC32_SCONSOLE,
800 };
801
802 static int pic32_uart_probe(struct platform_device *pdev)
803 {
804 struct device_node *np = pdev->dev.of_node;
805 struct pic32_sport *sport;
806 int uart_idx = 0;
807 struct resource *res_mem;
808 struct uart_port *port;
809 int ret;
810
811 uart_idx = of_alias_get_id(np, "serial");
812 if (uart_idx < 0 || uart_idx >= PIC32_MAX_UARTS)
813 return -EINVAL;
814
815 res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
816 if (!res_mem)
817 return -EINVAL;
818
819 sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
820 if (!sport)
821 return -ENOMEM;
822
823 sport->idx = uart_idx;
824 sport->irq_fault = irq_of_parse_and_map(np, 0);
825 sport->irqflags_fault = IRQF_NO_THREAD;
826 sport->irq_rx = irq_of_parse_and_map(np, 1);
827 sport->irqflags_rx = IRQF_NO_THREAD;
828 sport->irq_tx = irq_of_parse_and_map(np, 2);
829 sport->irqflags_tx = IRQF_NO_THREAD;
830 sport->clk = devm_clk_get(&pdev->dev, NULL);
831 sport->cts_gpio = -EINVAL;
832 sport->dev = &pdev->dev;
833
834 /* Hardware flow control: gpios
835 * !Note: Basically, CTS is needed for reading the status.
836 */
837 sport->hw_flow_ctrl = false;
838 sport->cts_gpio = of_get_named_gpio(np, "cts-gpios", 0);
839 if (gpio_is_valid(sport->cts_gpio)) {
840 sport->hw_flow_ctrl = true;
841
842 ret = devm_gpio_request(sport->dev,
843 sport->cts_gpio, "CTS");
844 if (ret) {
845 dev_err(&pdev->dev,
846 "error requesting CTS GPIO\n");
847 goto err;
848 }
849
850 ret = gpio_direction_input(sport->cts_gpio);
851 if (ret) {
852 dev_err(&pdev->dev, "error setting CTS GPIO\n");
853 goto err;
854 }
855 }
856
857 pic32_sports[uart_idx] = sport;
858 port = &sport->port;
859 memset(port, 0, sizeof(*port));
860 port->iotype = UPIO_MEM;
861 port->mapbase = res_mem->start;
862 port->ops = &pic32_uart_ops;
863 port->flags = UPF_BOOT_AUTOCONF;
864 port->dev = &pdev->dev;
865 port->fifosize = PIC32_UART_TX_FIFO_DEPTH;
866 port->uartclk = clk_get_rate(sport->clk);
867 port->line = uart_idx;
868
869 ret = uart_add_one_port(&pic32_uart_driver, port);
870 if (ret) {
871 port->membase = NULL;
872 dev_err(port->dev, "%s: uart add port error!\n", __func__);
873 goto err;
874 }
875
876 #ifdef CONFIG_SERIAL_PIC32_CONSOLE
877 if (is_pic32_console_port(port) &&
878 (pic32_console.flags & CON_ENABLED)) {
879 /* The peripheral clock has been enabled by console_setup,
880 * so disable it till the port is used.
881 */
882 pic32_disable_clock(sport);
883 }
884 #endif
885
886 platform_set_drvdata(pdev, port);
887
888 dev_info(&pdev->dev, "%s: uart(%d) driver initialized.\n",
889 __func__, uart_idx);
890
891 return 0;
892 err:
893 /* automatic unroll of sport and gpios */
894 return ret;
895 }
896
897 static int pic32_uart_remove(struct platform_device *pdev)
898 {
899 struct uart_port *port = platform_get_drvdata(pdev);
900 struct pic32_sport *sport = to_pic32_sport(port);
901
902 uart_remove_one_port(&pic32_uart_driver, port);
903 pic32_disable_clock(sport);
904 platform_set_drvdata(pdev, NULL);
905 pic32_sports[sport->idx] = NULL;
906
907 /* automatic unroll of sport and gpios */
908 return 0;
909 }
910
911 static const struct of_device_id pic32_serial_dt_ids[] = {
912 { .compatible = "microchip,pic32mzda-uart" },
913 { /* sentinel */ }
914 };
915 MODULE_DEVICE_TABLE(of, pic32_serial_dt_ids);
916
917 static struct platform_driver pic32_uart_platform_driver = {
918 .probe = pic32_uart_probe,
919 .remove = pic32_uart_remove,
920 .driver = {
921 .name = PIC32_DEV_NAME,
922 .of_match_table = of_match_ptr(pic32_serial_dt_ids),
923 },
924 };
925
926 static int __init pic32_uart_init(void)
927 {
928 int ret;
929
930 ret = uart_register_driver(&pic32_uart_driver);
931 if (ret) {
932 pr_err("failed to register %s:%d\n",
933 pic32_uart_driver.driver_name, ret);
934 return ret;
935 }
936
937 ret = platform_driver_register(&pic32_uart_platform_driver);
938 if (ret) {
939 pr_err("fail to register pic32 uart\n");
940 uart_unregister_driver(&pic32_uart_driver);
941 }
942
943 return ret;
944 }
945 arch_initcall(pic32_uart_init);
946
947 static void __exit pic32_uart_exit(void)
948 {
949 #ifdef CONFIG_SERIAL_PIC32_CONSOLE
950 unregister_console(&pic32_console);
951 #endif
952 platform_driver_unregister(&pic32_uart_platform_driver);
953 uart_unregister_driver(&pic32_uart_driver);
954 }
955 module_exit(pic32_uart_exit);
956
957 MODULE_AUTHOR("Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>");
958 MODULE_DESCRIPTION("Microchip PIC32 integrated serial port driver");
959 MODULE_LICENSE("GPL v2");
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