1 /*
2 * linux/drivers/mmc/card/sdio_uart.c - SDIO UART/GPS driver
3 *
4 * Based on drivers/serial/8250.c and drivers/serial/serial_core.c
5 * by Russell King.
6 *
7 * Author: Nicolas Pitre
8 * Created: June 15, 2007
9 * Copyright: MontaVista Software, Inc.
10 *
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License as published by
13 * the Free Software Foundation; either version 2 of the License, or (at
14 * your option) any later version.
15 */
16
17 /*
18 * Note: Although this driver assumes a 16550A-like UART implementation,
19 * it is not possible to leverage the common 8250/16550 driver, nor the
20 * core UART infrastructure, as they assumes direct access to the hardware
21 * registers, often under a spinlock. This is not possible in the SDIO
22 * context as SDIO access functions must be able to sleep.
23 *
24 * Because we need to lock the SDIO host to ensure an exclusive access to
25 * the card, we simply rely on that lock to also prevent and serialize
26 * concurrent access to the same port.
27 */
28
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/kernel.h>
32 #include <linux/sched.h>
33 #include <linux/mutex.h>
34 #include <linux/seq_file.h>
35 #include <linux/serial_reg.h>
36 #include <linux/circ_buf.h>
37 #include <linux/tty.h>
38 #include <linux/tty_flip.h>
39 #include <linux/kfifo.h>
40 #include <linux/slab.h>
41
42 #include <linux/mmc/core.h>
43 #include <linux/mmc/card.h>
44 #include <linux/mmc/sdio_func.h>
45 #include <linux/mmc/sdio_ids.h>
46
47
48 #define UART_NR 8 /* Number of UARTs this driver can handle */
49
50
51 #define FIFO_SIZE PAGE_SIZE
52 #define WAKEUP_CHARS 256
53
54 struct uart_icount {
55 __u32 cts;
56 __u32 dsr;
57 __u32 rng;
58 __u32 dcd;
59 __u32 rx;
60 __u32 tx;
61 __u32 frame;
62 __u32 overrun;
63 __u32 parity;
64 __u32 brk;
65 };
66
67 struct sdio_uart_port {
68 struct tty_port port;
69 unsigned int index;
70 struct sdio_func *func;
71 struct mutex func_lock;
72 struct task_struct *in_sdio_uart_irq;
73 unsigned int regs_offset;
74 struct kfifo xmit_fifo;
75 spinlock_t write_lock;
76 struct uart_icount icount;
77 unsigned int uartclk;
78 unsigned int mctrl;
79 unsigned int rx_mctrl;
80 unsigned int read_status_mask;
81 unsigned int ignore_status_mask;
82 unsigned char x_char;
83 unsigned char ier;
84 unsigned char lcr;
85 };
86
87 static struct sdio_uart_port *sdio_uart_table[UART_NR];
88 static DEFINE_SPINLOCK(sdio_uart_table_lock);
89
sdio_uart_add_port(struct sdio_uart_port * port)90 static int sdio_uart_add_port(struct sdio_uart_port *port)
91 {
92 int index, ret = -EBUSY;
93
94 mutex_init(&port->func_lock);
95 spin_lock_init(&port->write_lock);
96 if (kfifo_alloc(&port->xmit_fifo, FIFO_SIZE, GFP_KERNEL))
97 return -ENOMEM;
98
99 spin_lock(&sdio_uart_table_lock);
100 for (index = 0; index < UART_NR; index++) {
101 if (!sdio_uart_table[index]) {
102 port->index = index;
103 sdio_uart_table[index] = port;
104 ret = 0;
105 break;
106 }
107 }
108 spin_unlock(&sdio_uart_table_lock);
109
110 return ret;
111 }
112
sdio_uart_port_get(unsigned index)113 static struct sdio_uart_port *sdio_uart_port_get(unsigned index)
114 {
115 struct sdio_uart_port *port;
116
117 if (index >= UART_NR)
118 return NULL;
119
120 spin_lock(&sdio_uart_table_lock);
121 port = sdio_uart_table[index];
122 if (port)
123 tty_port_get(&port->port);
124 spin_unlock(&sdio_uart_table_lock);
125
126 return port;
127 }
128
sdio_uart_port_put(struct sdio_uart_port * port)129 static void sdio_uart_port_put(struct sdio_uart_port *port)
130 {
131 tty_port_put(&port->port);
132 }
133
sdio_uart_port_remove(struct sdio_uart_port * port)134 static void sdio_uart_port_remove(struct sdio_uart_port *port)
135 {
136 struct sdio_func *func;
137
138 BUG_ON(sdio_uart_table[port->index] != port);
139
140 spin_lock(&sdio_uart_table_lock);
141 sdio_uart_table[port->index] = NULL;
142 spin_unlock(&sdio_uart_table_lock);
143
144 /*
145 * We're killing a port that potentially still is in use by
146 * the tty layer. Be careful to prevent any further access
147 * to the SDIO function and arrange for the tty layer to
148 * give up on that port ASAP.
149 * Beware: the lock ordering is critical.
150 */
151 mutex_lock(&port->port.mutex);
152 mutex_lock(&port->func_lock);
153 func = port->func;
154 sdio_claim_host(func);
155 port->func = NULL;
156 mutex_unlock(&port->func_lock);
157 /* tty_hangup is async so is this safe as is ?? */
158 tty_port_tty_hangup(&port->port, false);
159 mutex_unlock(&port->port.mutex);
160 sdio_release_irq(func);
161 sdio_disable_func(func);
162 sdio_release_host(func);
163
164 sdio_uart_port_put(port);
165 }
166
sdio_uart_claim_func(struct sdio_uart_port * port)167 static int sdio_uart_claim_func(struct sdio_uart_port *port)
168 {
169 mutex_lock(&port->func_lock);
170 if (unlikely(!port->func)) {
171 mutex_unlock(&port->func_lock);
172 return -ENODEV;
173 }
174 if (likely(port->in_sdio_uart_irq != current))
175 sdio_claim_host(port->func);
176 mutex_unlock(&port->func_lock);
177 return 0;
178 }
179
sdio_uart_release_func(struct sdio_uart_port * port)180 static inline void sdio_uart_release_func(struct sdio_uart_port *port)
181 {
182 if (likely(port->in_sdio_uart_irq != current))
183 sdio_release_host(port->func);
184 }
185
sdio_in(struct sdio_uart_port * port,int offset)186 static inline unsigned int sdio_in(struct sdio_uart_port *port, int offset)
187 {
188 unsigned char c;
189 c = sdio_readb(port->func, port->regs_offset + offset, NULL);
190 return c;
191 }
192
sdio_out(struct sdio_uart_port * port,int offset,int value)193 static inline void sdio_out(struct sdio_uart_port *port, int offset, int value)
194 {
195 sdio_writeb(port->func, value, port->regs_offset + offset, NULL);
196 }
197
sdio_uart_get_mctrl(struct sdio_uart_port * port)198 static unsigned int sdio_uart_get_mctrl(struct sdio_uart_port *port)
199 {
200 unsigned char status;
201 unsigned int ret;
202
203 /* FIXME: What stops this losing the delta bits and breaking
204 sdio_uart_check_modem_status ? */
205 status = sdio_in(port, UART_MSR);
206
207 ret = 0;
208 if (status & UART_MSR_DCD)
209 ret |= TIOCM_CAR;
210 if (status & UART_MSR_RI)
211 ret |= TIOCM_RNG;
212 if (status & UART_MSR_DSR)
213 ret |= TIOCM_DSR;
214 if (status & UART_MSR_CTS)
215 ret |= TIOCM_CTS;
216 return ret;
217 }
218
sdio_uart_write_mctrl(struct sdio_uart_port * port,unsigned int mctrl)219 static void sdio_uart_write_mctrl(struct sdio_uart_port *port,
220 unsigned int mctrl)
221 {
222 unsigned char mcr = 0;
223
224 if (mctrl & TIOCM_RTS)
225 mcr |= UART_MCR_RTS;
226 if (mctrl & TIOCM_DTR)
227 mcr |= UART_MCR_DTR;
228 if (mctrl & TIOCM_OUT1)
229 mcr |= UART_MCR_OUT1;
230 if (mctrl & TIOCM_OUT2)
231 mcr |= UART_MCR_OUT2;
232 if (mctrl & TIOCM_LOOP)
233 mcr |= UART_MCR_LOOP;
234
235 sdio_out(port, UART_MCR, mcr);
236 }
237
sdio_uart_update_mctrl(struct sdio_uart_port * port,unsigned int set,unsigned int clear)238 static inline void sdio_uart_update_mctrl(struct sdio_uart_port *port,
239 unsigned int set, unsigned int clear)
240 {
241 unsigned int old;
242
243 old = port->mctrl;
244 port->mctrl = (old & ~clear) | set;
245 if (old != port->mctrl)
246 sdio_uart_write_mctrl(port, port->mctrl);
247 }
248
249 #define sdio_uart_set_mctrl(port, x) sdio_uart_update_mctrl(port, x, 0)
250 #define sdio_uart_clear_mctrl(port, x) sdio_uart_update_mctrl(port, 0, x)
251
sdio_uart_change_speed(struct sdio_uart_port * port,struct ktermios * termios,struct ktermios * old)252 static void sdio_uart_change_speed(struct sdio_uart_port *port,
253 struct ktermios *termios,
254 struct ktermios *old)
255 {
256 unsigned char cval, fcr = 0;
257 unsigned int baud, quot;
258
259 switch (termios->c_cflag & CSIZE) {
260 case CS5:
261 cval = UART_LCR_WLEN5;
262 break;
263 case CS6:
264 cval = UART_LCR_WLEN6;
265 break;
266 case CS7:
267 cval = UART_LCR_WLEN7;
268 break;
269 default:
270 case CS8:
271 cval = UART_LCR_WLEN8;
272 break;
273 }
274
275 if (termios->c_cflag & CSTOPB)
276 cval |= UART_LCR_STOP;
277 if (termios->c_cflag & PARENB)
278 cval |= UART_LCR_PARITY;
279 if (!(termios->c_cflag & PARODD))
280 cval |= UART_LCR_EPAR;
281
282 for (;;) {
283 baud = tty_termios_baud_rate(termios);
284 if (baud == 0)
285 baud = 9600; /* Special case: B0 rate. */
286 if (baud <= port->uartclk)
287 break;
288 /*
289 * Oops, the quotient was zero. Try again with the old
290 * baud rate if possible, otherwise default to 9600.
291 */
292 termios->c_cflag &= ~CBAUD;
293 if (old) {
294 termios->c_cflag |= old->c_cflag & CBAUD;
295 old = NULL;
296 } else
297 termios->c_cflag |= B9600;
298 }
299 quot = (2 * port->uartclk + baud) / (2 * baud);
300
301 if (baud < 2400)
302 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
303 else
304 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
305
306 port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
307 if (termios->c_iflag & INPCK)
308 port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
309 if (termios->c_iflag & (BRKINT | PARMRK))
310 port->read_status_mask |= UART_LSR_BI;
311
312 /*
313 * Characters to ignore
314 */
315 port->ignore_status_mask = 0;
316 if (termios->c_iflag & IGNPAR)
317 port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
318 if (termios->c_iflag & IGNBRK) {
319 port->ignore_status_mask |= UART_LSR_BI;
320 /*
321 * If we're ignoring parity and break indicators,
322 * ignore overruns too (for real raw support).
323 */
324 if (termios->c_iflag & IGNPAR)
325 port->ignore_status_mask |= UART_LSR_OE;
326 }
327
328 /*
329 * ignore all characters if CREAD is not set
330 */
331 if ((termios->c_cflag & CREAD) == 0)
332 port->ignore_status_mask |= UART_LSR_DR;
333
334 /*
335 * CTS flow control flag and modem status interrupts
336 */
337 port->ier &= ~UART_IER_MSI;
338 if ((termios->c_cflag & CRTSCTS) || !(termios->c_cflag & CLOCAL))
339 port->ier |= UART_IER_MSI;
340
341 port->lcr = cval;
342
343 sdio_out(port, UART_IER, port->ier);
344 sdio_out(port, UART_LCR, cval | UART_LCR_DLAB);
345 sdio_out(port, UART_DLL, quot & 0xff);
346 sdio_out(port, UART_DLM, quot >> 8);
347 sdio_out(port, UART_LCR, cval);
348 sdio_out(port, UART_FCR, fcr);
349
350 sdio_uart_write_mctrl(port, port->mctrl);
351 }
352
sdio_uart_start_tx(struct sdio_uart_port * port)353 static void sdio_uart_start_tx(struct sdio_uart_port *port)
354 {
355 if (!(port->ier & UART_IER_THRI)) {
356 port->ier |= UART_IER_THRI;
357 sdio_out(port, UART_IER, port->ier);
358 }
359 }
360
sdio_uart_stop_tx(struct sdio_uart_port * port)361 static void sdio_uart_stop_tx(struct sdio_uart_port *port)
362 {
363 if (port->ier & UART_IER_THRI) {
364 port->ier &= ~UART_IER_THRI;
365 sdio_out(port, UART_IER, port->ier);
366 }
367 }
368
sdio_uart_stop_rx(struct sdio_uart_port * port)369 static void sdio_uart_stop_rx(struct sdio_uart_port *port)
370 {
371 port->ier &= ~UART_IER_RLSI;
372 port->read_status_mask &= ~UART_LSR_DR;
373 sdio_out(port, UART_IER, port->ier);
374 }
375
sdio_uart_receive_chars(struct sdio_uart_port * port,unsigned int * status)376 static void sdio_uart_receive_chars(struct sdio_uart_port *port,
377 unsigned int *status)
378 {
379 unsigned int ch, flag;
380 int max_count = 256;
381
382 do {
383 ch = sdio_in(port, UART_RX);
384 flag = TTY_NORMAL;
385 port->icount.rx++;
386
387 if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
388 UART_LSR_FE | UART_LSR_OE))) {
389 /*
390 * For statistics only
391 */
392 if (*status & UART_LSR_BI) {
393 *status &= ~(UART_LSR_FE | UART_LSR_PE);
394 port->icount.brk++;
395 } else if (*status & UART_LSR_PE)
396 port->icount.parity++;
397 else if (*status & UART_LSR_FE)
398 port->icount.frame++;
399 if (*status & UART_LSR_OE)
400 port->icount.overrun++;
401
402 /*
403 * Mask off conditions which should be ignored.
404 */
405 *status &= port->read_status_mask;
406 if (*status & UART_LSR_BI)
407 flag = TTY_BREAK;
408 else if (*status & UART_LSR_PE)
409 flag = TTY_PARITY;
410 else if (*status & UART_LSR_FE)
411 flag = TTY_FRAME;
412 }
413
414 if ((*status & port->ignore_status_mask & ~UART_LSR_OE) == 0)
415 tty_insert_flip_char(&port->port, ch, flag);
416
417 /*
418 * Overrun is special. Since it's reported immediately,
419 * it doesn't affect the current character.
420 */
421 if (*status & ~port->ignore_status_mask & UART_LSR_OE)
422 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
423
424 *status = sdio_in(port, UART_LSR);
425 } while ((*status & UART_LSR_DR) && (max_count-- > 0));
426
427 tty_flip_buffer_push(&port->port);
428 }
429
sdio_uart_transmit_chars(struct sdio_uart_port * port)430 static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
431 {
432 struct kfifo *xmit = &port->xmit_fifo;
433 int count;
434 struct tty_struct *tty;
435 u8 iobuf[16];
436 int len;
437
438 if (port->x_char) {
439 sdio_out(port, UART_TX, port->x_char);
440 port->icount.tx++;
441 port->x_char = 0;
442 return;
443 }
444
445 tty = tty_port_tty_get(&port->port);
446
447 if (tty == NULL || !kfifo_len(xmit) ||
448 tty->stopped || tty->hw_stopped) {
449 sdio_uart_stop_tx(port);
450 tty_kref_put(tty);
451 return;
452 }
453
454 len = kfifo_out_locked(xmit, iobuf, 16, &port->write_lock);
455 for (count = 0; count < len; count++) {
456 sdio_out(port, UART_TX, iobuf[count]);
457 port->icount.tx++;
458 }
459
460 len = kfifo_len(xmit);
461 if (len < WAKEUP_CHARS) {
462 tty_wakeup(tty);
463 if (len == 0)
464 sdio_uart_stop_tx(port);
465 }
466 tty_kref_put(tty);
467 }
468
sdio_uart_check_modem_status(struct sdio_uart_port * port)469 static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
470 {
471 int status;
472 struct tty_struct *tty;
473
474 status = sdio_in(port, UART_MSR);
475
476 if ((status & UART_MSR_ANY_DELTA) == 0)
477 return;
478
479 if (status & UART_MSR_TERI)
480 port->icount.rng++;
481 if (status & UART_MSR_DDSR)
482 port->icount.dsr++;
483 if (status & UART_MSR_DDCD) {
484 port->icount.dcd++;
485 /* DCD raise - wake for open */
486 if (status & UART_MSR_DCD)
487 wake_up_interruptible(&port->port.open_wait);
488 else {
489 /* DCD drop - hang up if tty attached */
490 tty_port_tty_hangup(&port->port, false);
491 }
492 }
493 if (status & UART_MSR_DCTS) {
494 port->icount.cts++;
495 tty = tty_port_tty_get(&port->port);
496 if (tty && (tty->termios.c_cflag & CRTSCTS)) {
497 int cts = (status & UART_MSR_CTS);
498 if (tty->hw_stopped) {
499 if (cts) {
500 tty->hw_stopped = 0;
501 sdio_uart_start_tx(port);
502 tty_wakeup(tty);
503 }
504 } else {
505 if (!cts) {
506 tty->hw_stopped = 1;
507 sdio_uart_stop_tx(port);
508 }
509 }
510 }
511 tty_kref_put(tty);
512 }
513 }
514
515 /*
516 * This handles the interrupt from one port.
517 */
sdio_uart_irq(struct sdio_func * func)518 static void sdio_uart_irq(struct sdio_func *func)
519 {
520 struct sdio_uart_port *port = sdio_get_drvdata(func);
521 unsigned int iir, lsr;
522
523 /*
524 * In a few places sdio_uart_irq() is called directly instead of
525 * waiting for the actual interrupt to be raised and the SDIO IRQ
526 * thread scheduled in order to reduce latency. However, some
527 * interaction with the tty core may end up calling us back
528 * (serial echo, flow control, etc.) through those same places
529 * causing undesirable effects. Let's stop the recursion here.
530 */
531 if (unlikely(port->in_sdio_uart_irq == current))
532 return;
533
534 iir = sdio_in(port, UART_IIR);
535 if (iir & UART_IIR_NO_INT)
536 return;
537
538 port->in_sdio_uart_irq = current;
539 lsr = sdio_in(port, UART_LSR);
540 if (lsr & UART_LSR_DR)
541 sdio_uart_receive_chars(port, &lsr);
542 sdio_uart_check_modem_status(port);
543 if (lsr & UART_LSR_THRE)
544 sdio_uart_transmit_chars(port);
545 port->in_sdio_uart_irq = NULL;
546 }
547
uart_carrier_raised(struct tty_port * tport)548 static int uart_carrier_raised(struct tty_port *tport)
549 {
550 struct sdio_uart_port *port =
551 container_of(tport, struct sdio_uart_port, port);
552 unsigned int ret = sdio_uart_claim_func(port);
553 if (ret) /* Missing hardware shouldn't block for carrier */
554 return 1;
555 ret = sdio_uart_get_mctrl(port);
556 sdio_uart_release_func(port);
557 if (ret & TIOCM_CAR)
558 return 1;
559 return 0;
560 }
561
562 /**
563 * uart_dtr_rts - port helper to set uart signals
564 * @tport: tty port to be updated
565 * @onoff: set to turn on DTR/RTS
566 *
567 * Called by the tty port helpers when the modem signals need to be
568 * adjusted during an open, close and hangup.
569 */
570
uart_dtr_rts(struct tty_port * tport,int onoff)571 static void uart_dtr_rts(struct tty_port *tport, int onoff)
572 {
573 struct sdio_uart_port *port =
574 container_of(tport, struct sdio_uart_port, port);
575 int ret = sdio_uart_claim_func(port);
576 if (ret)
577 return;
578 if (onoff == 0)
579 sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
580 else
581 sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
582 sdio_uart_release_func(port);
583 }
584
585 /**
586 * sdio_uart_activate - start up hardware
587 * @tport: tty port to activate
588 * @tty: tty bound to this port
589 *
590 * Activate a tty port. The port locking guarantees us this will be
591 * run exactly once per set of opens, and if successful will see the
592 * shutdown method run exactly once to match. Start up and shutdown are
593 * protected from each other by the internal locking and will not run
594 * at the same time even during a hangup event.
595 *
596 * If we successfully start up the port we take an extra kref as we
597 * will keep it around until shutdown when the kref is dropped.
598 */
599
sdio_uart_activate(struct tty_port * tport,struct tty_struct * tty)600 static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
601 {
602 struct sdio_uart_port *port =
603 container_of(tport, struct sdio_uart_port, port);
604 int ret;
605
606 /*
607 * Set the TTY IO error marker - we will only clear this
608 * once we have successfully opened the port.
609 */
610 set_bit(TTY_IO_ERROR, &tty->flags);
611
612 kfifo_reset(&port->xmit_fifo);
613
614 ret = sdio_uart_claim_func(port);
615 if (ret)
616 return ret;
617 ret = sdio_enable_func(port->func);
618 if (ret)
619 goto err1;
620 ret = sdio_claim_irq(port->func, sdio_uart_irq);
621 if (ret)
622 goto err2;
623
624 /*
625 * Clear the FIFO buffers and disable them.
626 * (they will be reenabled in sdio_change_speed())
627 */
628 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
629 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
630 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
631 sdio_out(port, UART_FCR, 0);
632
633 /*
634 * Clear the interrupt registers.
635 */
636 (void) sdio_in(port, UART_LSR);
637 (void) sdio_in(port, UART_RX);
638 (void) sdio_in(port, UART_IIR);
639 (void) sdio_in(port, UART_MSR);
640
641 /*
642 * Now, initialize the UART
643 */
644 sdio_out(port, UART_LCR, UART_LCR_WLEN8);
645
646 port->ier = UART_IER_RLSI|UART_IER_RDI|UART_IER_RTOIE|UART_IER_UUE;
647 port->mctrl = TIOCM_OUT2;
648
649 sdio_uart_change_speed(port, &tty->termios, NULL);
650
651 if (tty->termios.c_cflag & CBAUD)
652 sdio_uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
653
654 if (tty->termios.c_cflag & CRTSCTS)
655 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS))
656 tty->hw_stopped = 1;
657
658 clear_bit(TTY_IO_ERROR, &tty->flags);
659
660 /* Kick the IRQ handler once while we're still holding the host lock */
661 sdio_uart_irq(port->func);
662
663 sdio_uart_release_func(port);
664 return 0;
665
666 err2:
667 sdio_disable_func(port->func);
668 err1:
669 sdio_uart_release_func(port);
670 return ret;
671 }
672
673 /**
674 * sdio_uart_shutdown - stop hardware
675 * @tport: tty port to shut down
676 *
677 * Deactivate a tty port. The port locking guarantees us this will be
678 * run only if a successful matching activate already ran. The two are
679 * protected from each other by the internal locking and will not run
680 * at the same time even during a hangup event.
681 */
682
sdio_uart_shutdown(struct tty_port * tport)683 static void sdio_uart_shutdown(struct tty_port *tport)
684 {
685 struct sdio_uart_port *port =
686 container_of(tport, struct sdio_uart_port, port);
687 int ret;
688
689 ret = sdio_uart_claim_func(port);
690 if (ret)
691 return;
692
693 sdio_uart_stop_rx(port);
694
695 /* Disable interrupts from this port */
696 sdio_release_irq(port->func);
697 port->ier = 0;
698 sdio_out(port, UART_IER, 0);
699
700 sdio_uart_clear_mctrl(port, TIOCM_OUT2);
701
702 /* Disable break condition and FIFOs. */
703 port->lcr &= ~UART_LCR_SBC;
704 sdio_out(port, UART_LCR, port->lcr);
705 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
706 UART_FCR_CLEAR_RCVR |
707 UART_FCR_CLEAR_XMIT);
708 sdio_out(port, UART_FCR, 0);
709
710 sdio_disable_func(port->func);
711
712 sdio_uart_release_func(port);
713 }
714
sdio_uart_port_destroy(struct tty_port * tport)715 static void sdio_uart_port_destroy(struct tty_port *tport)
716 {
717 struct sdio_uart_port *port =
718 container_of(tport, struct sdio_uart_port, port);
719 kfifo_free(&port->xmit_fifo);
720 kfree(port);
721 }
722
723 /**
724 * sdio_uart_install - install method
725 * @driver: the driver in use (sdio_uart in our case)
726 * @tty: the tty being bound
727 *
728 * Look up and bind the tty and the driver together. Initialize
729 * any needed private data (in our case the termios)
730 */
731
sdio_uart_install(struct tty_driver * driver,struct tty_struct * tty)732 static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
733 {
734 int idx = tty->index;
735 struct sdio_uart_port *port = sdio_uart_port_get(idx);
736 int ret = tty_standard_install(driver, tty);
737
738 if (ret == 0)
739 /* This is the ref sdio_uart_port get provided */
740 tty->driver_data = port;
741 else
742 sdio_uart_port_put(port);
743 return ret;
744 }
745
746 /**
747 * sdio_uart_cleanup - called on the last tty kref drop
748 * @tty: the tty being destroyed
749 *
750 * Called asynchronously when the last reference to the tty is dropped.
751 * We cannot destroy the tty->driver_data port kref until this point
752 */
753
sdio_uart_cleanup(struct tty_struct * tty)754 static void sdio_uart_cleanup(struct tty_struct *tty)
755 {
756 struct sdio_uart_port *port = tty->driver_data;
757 tty->driver_data = NULL; /* Bug trap */
758 sdio_uart_port_put(port);
759 }
760
761 /*
762 * Open/close/hangup is now entirely boilerplate
763 */
764
sdio_uart_open(struct tty_struct * tty,struct file * filp)765 static int sdio_uart_open(struct tty_struct *tty, struct file *filp)
766 {
767 struct sdio_uart_port *port = tty->driver_data;
768 return tty_port_open(&port->port, tty, filp);
769 }
770
sdio_uart_close(struct tty_struct * tty,struct file * filp)771 static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
772 {
773 struct sdio_uart_port *port = tty->driver_data;
774 tty_port_close(&port->port, tty, filp);
775 }
776
sdio_uart_hangup(struct tty_struct * tty)777 static void sdio_uart_hangup(struct tty_struct *tty)
778 {
779 struct sdio_uart_port *port = tty->driver_data;
780 tty_port_hangup(&port->port);
781 }
782
sdio_uart_write(struct tty_struct * tty,const unsigned char * buf,int count)783 static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf,
784 int count)
785 {
786 struct sdio_uart_port *port = tty->driver_data;
787 int ret;
788
789 if (!port->func)
790 return -ENODEV;
791
792 ret = kfifo_in_locked(&port->xmit_fifo, buf, count, &port->write_lock);
793 if (!(port->ier & UART_IER_THRI)) {
794 int err = sdio_uart_claim_func(port);
795 if (!err) {
796 sdio_uart_start_tx(port);
797 sdio_uart_irq(port->func);
798 sdio_uart_release_func(port);
799 } else
800 ret = err;
801 }
802
803 return ret;
804 }
805
sdio_uart_write_room(struct tty_struct * tty)806 static int sdio_uart_write_room(struct tty_struct *tty)
807 {
808 struct sdio_uart_port *port = tty->driver_data;
809 return FIFO_SIZE - kfifo_len(&port->xmit_fifo);
810 }
811
sdio_uart_chars_in_buffer(struct tty_struct * tty)812 static int sdio_uart_chars_in_buffer(struct tty_struct *tty)
813 {
814 struct sdio_uart_port *port = tty->driver_data;
815 return kfifo_len(&port->xmit_fifo);
816 }
817
sdio_uart_send_xchar(struct tty_struct * tty,char ch)818 static void sdio_uart_send_xchar(struct tty_struct *tty, char ch)
819 {
820 struct sdio_uart_port *port = tty->driver_data;
821
822 port->x_char = ch;
823 if (ch && !(port->ier & UART_IER_THRI)) {
824 if (sdio_uart_claim_func(port) != 0)
825 return;
826 sdio_uart_start_tx(port);
827 sdio_uart_irq(port->func);
828 sdio_uart_release_func(port);
829 }
830 }
831
sdio_uart_throttle(struct tty_struct * tty)832 static void sdio_uart_throttle(struct tty_struct *tty)
833 {
834 struct sdio_uart_port *port = tty->driver_data;
835
836 if (!I_IXOFF(tty) && !(tty->termios.c_cflag & CRTSCTS))
837 return;
838
839 if (sdio_uart_claim_func(port) != 0)
840 return;
841
842 if (I_IXOFF(tty)) {
843 port->x_char = STOP_CHAR(tty);
844 sdio_uart_start_tx(port);
845 }
846
847 if (tty->termios.c_cflag & CRTSCTS)
848 sdio_uart_clear_mctrl(port, TIOCM_RTS);
849
850 sdio_uart_irq(port->func);
851 sdio_uart_release_func(port);
852 }
853
sdio_uart_unthrottle(struct tty_struct * tty)854 static void sdio_uart_unthrottle(struct tty_struct *tty)
855 {
856 struct sdio_uart_port *port = tty->driver_data;
857
858 if (!I_IXOFF(tty) && !(tty->termios.c_cflag & CRTSCTS))
859 return;
860
861 if (sdio_uart_claim_func(port) != 0)
862 return;
863
864 if (I_IXOFF(tty)) {
865 if (port->x_char) {
866 port->x_char = 0;
867 } else {
868 port->x_char = START_CHAR(tty);
869 sdio_uart_start_tx(port);
870 }
871 }
872
873 if (tty->termios.c_cflag & CRTSCTS)
874 sdio_uart_set_mctrl(port, TIOCM_RTS);
875
876 sdio_uart_irq(port->func);
877 sdio_uart_release_func(port);
878 }
879
sdio_uart_set_termios(struct tty_struct * tty,struct ktermios * old_termios)880 static void sdio_uart_set_termios(struct tty_struct *tty,
881 struct ktermios *old_termios)
882 {
883 struct sdio_uart_port *port = tty->driver_data;
884 unsigned int cflag = tty->termios.c_cflag;
885
886 if (sdio_uart_claim_func(port) != 0)
887 return;
888
889 sdio_uart_change_speed(port, &tty->termios, old_termios);
890
891 /* Handle transition to B0 status */
892 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
893 sdio_uart_clear_mctrl(port, TIOCM_RTS | TIOCM_DTR);
894
895 /* Handle transition away from B0 status */
896 if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
897 unsigned int mask = TIOCM_DTR;
898 if (!(cflag & CRTSCTS) || !test_bit(TTY_THROTTLED, &tty->flags))
899 mask |= TIOCM_RTS;
900 sdio_uart_set_mctrl(port, mask);
901 }
902
903 /* Handle turning off CRTSCTS */
904 if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
905 tty->hw_stopped = 0;
906 sdio_uart_start_tx(port);
907 }
908
909 /* Handle turning on CRTSCTS */
910 if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
911 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS)) {
912 tty->hw_stopped = 1;
913 sdio_uart_stop_tx(port);
914 }
915 }
916
917 sdio_uart_release_func(port);
918 }
919
sdio_uart_break_ctl(struct tty_struct * tty,int break_state)920 static int sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
921 {
922 struct sdio_uart_port *port = tty->driver_data;
923 int result;
924
925 result = sdio_uart_claim_func(port);
926 if (result != 0)
927 return result;
928
929 if (break_state == -1)
930 port->lcr |= UART_LCR_SBC;
931 else
932 port->lcr &= ~UART_LCR_SBC;
933 sdio_out(port, UART_LCR, port->lcr);
934
935 sdio_uart_release_func(port);
936 return 0;
937 }
938
sdio_uart_tiocmget(struct tty_struct * tty)939 static int sdio_uart_tiocmget(struct tty_struct *tty)
940 {
941 struct sdio_uart_port *port = tty->driver_data;
942 int result;
943
944 result = sdio_uart_claim_func(port);
945 if (!result) {
946 result = port->mctrl | sdio_uart_get_mctrl(port);
947 sdio_uart_release_func(port);
948 }
949
950 return result;
951 }
952
sdio_uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)953 static int sdio_uart_tiocmset(struct tty_struct *tty,
954 unsigned int set, unsigned int clear)
955 {
956 struct sdio_uart_port *port = tty->driver_data;
957 int result;
958
959 result = sdio_uart_claim_func(port);
960 if (!result) {
961 sdio_uart_update_mctrl(port, set, clear);
962 sdio_uart_release_func(port);
963 }
964
965 return result;
966 }
967
sdio_uart_proc_show(struct seq_file * m,void * v)968 static int sdio_uart_proc_show(struct seq_file *m, void *v)
969 {
970 int i;
971
972 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n",
973 "", "", "");
974 for (i = 0; i < UART_NR; i++) {
975 struct sdio_uart_port *port = sdio_uart_port_get(i);
976 if (port) {
977 seq_printf(m, "%d: uart:SDIO", i);
978 if (capable(CAP_SYS_ADMIN)) {
979 seq_printf(m, " tx:%d rx:%d",
980 port->icount.tx, port->icount.rx);
981 if (port->icount.frame)
982 seq_printf(m, " fe:%d",
983 port->icount.frame);
984 if (port->icount.parity)
985 seq_printf(m, " pe:%d",
986 port->icount.parity);
987 if (port->icount.brk)
988 seq_printf(m, " brk:%d",
989 port->icount.brk);
990 if (port->icount.overrun)
991 seq_printf(m, " oe:%d",
992 port->icount.overrun);
993 if (port->icount.cts)
994 seq_printf(m, " cts:%d",
995 port->icount.cts);
996 if (port->icount.dsr)
997 seq_printf(m, " dsr:%d",
998 port->icount.dsr);
999 if (port->icount.rng)
1000 seq_printf(m, " rng:%d",
1001 port->icount.rng);
1002 if (port->icount.dcd)
1003 seq_printf(m, " dcd:%d",
1004 port->icount.dcd);
1005 }
1006 sdio_uart_port_put(port);
1007 seq_putc(m, '\n');
1008 }
1009 }
1010 return 0;
1011 }
1012
sdio_uart_proc_open(struct inode * inode,struct file * file)1013 static int sdio_uart_proc_open(struct inode *inode, struct file *file)
1014 {
1015 return single_open(file, sdio_uart_proc_show, NULL);
1016 }
1017
1018 static const struct file_operations sdio_uart_proc_fops = {
1019 .owner = THIS_MODULE,
1020 .open = sdio_uart_proc_open,
1021 .read = seq_read,
1022 .llseek = seq_lseek,
1023 .release = single_release,
1024 };
1025
1026 static const struct tty_port_operations sdio_uart_port_ops = {
1027 .dtr_rts = uart_dtr_rts,
1028 .carrier_raised = uart_carrier_raised,
1029 .shutdown = sdio_uart_shutdown,
1030 .activate = sdio_uart_activate,
1031 .destruct = sdio_uart_port_destroy,
1032 };
1033
1034 static const struct tty_operations sdio_uart_ops = {
1035 .open = sdio_uart_open,
1036 .close = sdio_uart_close,
1037 .write = sdio_uart_write,
1038 .write_room = sdio_uart_write_room,
1039 .chars_in_buffer = sdio_uart_chars_in_buffer,
1040 .send_xchar = sdio_uart_send_xchar,
1041 .throttle = sdio_uart_throttle,
1042 .unthrottle = sdio_uart_unthrottle,
1043 .set_termios = sdio_uart_set_termios,
1044 .hangup = sdio_uart_hangup,
1045 .break_ctl = sdio_uart_break_ctl,
1046 .tiocmget = sdio_uart_tiocmget,
1047 .tiocmset = sdio_uart_tiocmset,
1048 .install = sdio_uart_install,
1049 .cleanup = sdio_uart_cleanup,
1050 .proc_fops = &sdio_uart_proc_fops,
1051 };
1052
1053 static struct tty_driver *sdio_uart_tty_driver;
1054
sdio_uart_probe(struct sdio_func * func,const struct sdio_device_id * id)1055 static int sdio_uart_probe(struct sdio_func *func,
1056 const struct sdio_device_id *id)
1057 {
1058 struct sdio_uart_port *port;
1059 int ret;
1060
1061 port = kzalloc(sizeof(struct sdio_uart_port), GFP_KERNEL);
1062 if (!port)
1063 return -ENOMEM;
1064
1065 if (func->class == SDIO_CLASS_UART) {
1066 pr_warn("%s: need info on UART class basic setup\n",
1067 sdio_func_id(func));
1068 kfree(port);
1069 return -ENOSYS;
1070 } else if (func->class == SDIO_CLASS_GPS) {
1071 /*
1072 * We need tuple 0x91. It contains SUBTPL_SIOREG
1073 * and SUBTPL_RCVCAPS.
1074 */
1075 struct sdio_func_tuple *tpl;
1076 for (tpl = func->tuples; tpl; tpl = tpl->next) {
1077 if (tpl->code != 0x91)
1078 continue;
1079 if (tpl->size < 10)
1080 continue;
1081 if (tpl->data[1] == 0) /* SUBTPL_SIOREG */
1082 break;
1083 }
1084 if (!tpl) {
1085 pr_warn("%s: can't find tuple 0x91 subtuple 0 (SUBTPL_SIOREG) for GPS class\n",
1086 sdio_func_id(func));
1087 kfree(port);
1088 return -EINVAL;
1089 }
1090 pr_debug("%s: Register ID = 0x%02x, Exp ID = 0x%02x\n",
1091 sdio_func_id(func), tpl->data[2], tpl->data[3]);
1092 port->regs_offset = (tpl->data[4] << 0) |
1093 (tpl->data[5] << 8) |
1094 (tpl->data[6] << 16);
1095 pr_debug("%s: regs offset = 0x%x\n",
1096 sdio_func_id(func), port->regs_offset);
1097 port->uartclk = tpl->data[7] * 115200;
1098 if (port->uartclk == 0)
1099 port->uartclk = 115200;
1100 pr_debug("%s: clk %d baudcode %u 4800-div %u\n",
1101 sdio_func_id(func), port->uartclk,
1102 tpl->data[7], tpl->data[8] | (tpl->data[9] << 8));
1103 } else {
1104 kfree(port);
1105 return -EINVAL;
1106 }
1107
1108 port->func = func;
1109 sdio_set_drvdata(func, port);
1110 tty_port_init(&port->port);
1111 port->port.ops = &sdio_uart_port_ops;
1112
1113 ret = sdio_uart_add_port(port);
1114 if (ret) {
1115 kfree(port);
1116 } else {
1117 struct device *dev;
1118 dev = tty_port_register_device(&port->port,
1119 sdio_uart_tty_driver, port->index, &func->dev);
1120 if (IS_ERR(dev)) {
1121 sdio_uart_port_remove(port);
1122 ret = PTR_ERR(dev);
1123 }
1124 }
1125
1126 return ret;
1127 }
1128
sdio_uart_remove(struct sdio_func * func)1129 static void sdio_uart_remove(struct sdio_func *func)
1130 {
1131 struct sdio_uart_port *port = sdio_get_drvdata(func);
1132
1133 tty_unregister_device(sdio_uart_tty_driver, port->index);
1134 sdio_uart_port_remove(port);
1135 }
1136
1137 static const struct sdio_device_id sdio_uart_ids[] = {
1138 { SDIO_DEVICE_CLASS(SDIO_CLASS_UART) },
1139 { SDIO_DEVICE_CLASS(SDIO_CLASS_GPS) },
1140 { /* end: all zeroes */ },
1141 };
1142
1143 MODULE_DEVICE_TABLE(sdio, sdio_uart_ids);
1144
1145 static struct sdio_driver sdio_uart_driver = {
1146 .probe = sdio_uart_probe,
1147 .remove = sdio_uart_remove,
1148 .name = "sdio_uart",
1149 .id_table = sdio_uart_ids,
1150 };
1151
sdio_uart_init(void)1152 static int __init sdio_uart_init(void)
1153 {
1154 int ret;
1155 struct tty_driver *tty_drv;
1156
1157 sdio_uart_tty_driver = tty_drv = alloc_tty_driver(UART_NR);
1158 if (!tty_drv)
1159 return -ENOMEM;
1160
1161 tty_drv->driver_name = "sdio_uart";
1162 tty_drv->name = "ttySDIO";
1163 tty_drv->major = 0; /* dynamically allocated */
1164 tty_drv->minor_start = 0;
1165 tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
1166 tty_drv->subtype = SERIAL_TYPE_NORMAL;
1167 tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1168 tty_drv->init_termios = tty_std_termios;
1169 tty_drv->init_termios.c_cflag = B4800 | CS8 | CREAD | HUPCL | CLOCAL;
1170 tty_drv->init_termios.c_ispeed = 4800;
1171 tty_drv->init_termios.c_ospeed = 4800;
1172 tty_set_operations(tty_drv, &sdio_uart_ops);
1173
1174 ret = tty_register_driver(tty_drv);
1175 if (ret)
1176 goto err1;
1177
1178 ret = sdio_register_driver(&sdio_uart_driver);
1179 if (ret)
1180 goto err2;
1181
1182 return 0;
1183
1184 err2:
1185 tty_unregister_driver(tty_drv);
1186 err1:
1187 put_tty_driver(tty_drv);
1188 return ret;
1189 }
1190
sdio_uart_exit(void)1191 static void __exit sdio_uart_exit(void)
1192 {
1193 sdio_unregister_driver(&sdio_uart_driver);
1194 tty_unregister_driver(sdio_uart_tty_driver);
1195 put_tty_driver(sdio_uart_tty_driver);
1196 }
1197
1198 module_init(sdio_uart_init);
1199 module_exit(sdio_uart_exit);
1200
1201 MODULE_AUTHOR("Nicolas Pitre");
1202 MODULE_LICENSE("GPL");
1203