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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * SDIO UART/GPS driver
4 *
5 * Based on drivers/serial/8250.c and drivers/serial/serial_core.c
6 * by Russell King.
7 *
8 * Author: Nicolas Pitre
9 * Created: June 15, 2007
10 * Copyright: MontaVista Software, Inc.
11 */
12
13/*
14 * Note: Although this driver assumes a 16550A-like UART implementation,
15 * it is not possible to leverage the common 8250/16550 driver, nor the
16 * core UART infrastructure, as they assumes direct access to the hardware
17 * registers, often under a spinlock. This is not possible in the SDIO
18 * context as SDIO access functions must be able to sleep.
19 *
20 * Because we need to lock the SDIO host to ensure an exclusive access to
21 * the card, we simply rely on that lock to also prevent and serialize
22 * concurrent access to the same port.
23 */
24
25#include <linux/module.h>
26#include <linux/init.h>
27#include <linux/kernel.h>
28#include <linux/sched.h>
29#include <linux/mutex.h>
30#include <linux/seq_file.h>
31#include <linux/serial_reg.h>
32#include <linux/circ_buf.h>
33#include <linux/tty.h>
34#include <linux/tty_flip.h>
35#include <linux/kfifo.h>
36#include <linux/slab.h>
37
38#include <linux/mmc/core.h>
39#include <linux/mmc/card.h>
40#include <linux/mmc/sdio_func.h>
41#include <linux/mmc/sdio_ids.h>
42
43
44#define UART_NR 8 /* Number of UARTs this driver can handle */
45
46
47#define FIFO_SIZE PAGE_SIZE
48#define WAKEUP_CHARS 256
49
50struct uart_icount {
51 __u32 cts;
52 __u32 dsr;
53 __u32 rng;
54 __u32 dcd;
55 __u32 rx;
56 __u32 tx;
57 __u32 frame;
58 __u32 overrun;
59 __u32 parity;
60 __u32 brk;
61};
62
63struct sdio_uart_port {
64 struct tty_port port;
65 unsigned int index;
66 struct sdio_func *func;
67 struct mutex func_lock;
68 struct task_struct *in_sdio_uart_irq;
69 unsigned int regs_offset;
70 struct kfifo xmit_fifo;
71 spinlock_t write_lock;
72 struct uart_icount icount;
73 unsigned int uartclk;
74 unsigned int mctrl;
75 unsigned int rx_mctrl;
76 unsigned int read_status_mask;
77 unsigned int ignore_status_mask;
78 unsigned char x_char;
79 unsigned char ier;
80 unsigned char lcr;
81};
82
83static struct sdio_uart_port *sdio_uart_table[UART_NR];
84static DEFINE_SPINLOCK(sdio_uart_table_lock);
85
86static int sdio_uart_add_port(struct sdio_uart_port *port)
87{
88 int index, ret = -EBUSY;
89
90 mutex_init(&port->func_lock);
91 spin_lock_init(&port->write_lock);
92 if (kfifo_alloc(&port->xmit_fifo, FIFO_SIZE, GFP_KERNEL))
93 return -ENOMEM;
94
95 spin_lock(&sdio_uart_table_lock);
96 for (index = 0; index < UART_NR; index++) {
97 if (!sdio_uart_table[index]) {
98 port->index = index;
99 sdio_uart_table[index] = port;
100 ret = 0;
101 break;
102 }
103 }
104 spin_unlock(&sdio_uart_table_lock);
105
106 return ret;
107}
108
109static struct sdio_uart_port *sdio_uart_port_get(unsigned index)
110{
111 struct sdio_uart_port *port;
112
113 if (index >= UART_NR)
114 return NULL;
115
116 spin_lock(&sdio_uart_table_lock);
117 port = sdio_uart_table[index];
118 if (port)
119 tty_port_get(&port->port);
120 spin_unlock(&sdio_uart_table_lock);
121
122 return port;
123}
124
125static void sdio_uart_port_put(struct sdio_uart_port *port)
126{
127 tty_port_put(&port->port);
128}
129
130static void sdio_uart_port_remove(struct sdio_uart_port *port)
131{
132 struct sdio_func *func;
133
134 spin_lock(&sdio_uart_table_lock);
135 sdio_uart_table[port->index] = NULL;
136 spin_unlock(&sdio_uart_table_lock);
137
138 /*
139 * We're killing a port that potentially still is in use by
140 * the tty layer. Be careful to prevent any further access
141 * to the SDIO function and arrange for the tty layer to
142 * give up on that port ASAP.
143 * Beware: the lock ordering is critical.
144 */
145 mutex_lock(&port->port.mutex);
146 mutex_lock(&port->func_lock);
147 func = port->func;
148 sdio_claim_host(func);
149 port->func = NULL;
150 mutex_unlock(&port->func_lock);
151 /* tty_hangup is async so is this safe as is ?? */
152 tty_port_tty_hangup(&port->port, false);
153 mutex_unlock(&port->port.mutex);
154 sdio_release_irq(func);
155 sdio_disable_func(func);
156 sdio_release_host(func);
157
158 sdio_uart_port_put(port);
159}
160
161static int sdio_uart_claim_func(struct sdio_uart_port *port)
162{
163 mutex_lock(&port->func_lock);
164 if (unlikely(!port->func)) {
165 mutex_unlock(&port->func_lock);
166 return -ENODEV;
167 }
168 if (likely(port->in_sdio_uart_irq != current))
169 sdio_claim_host(port->func);
170 mutex_unlock(&port->func_lock);
171 return 0;
172}
173
174static inline void sdio_uart_release_func(struct sdio_uart_port *port)
175{
176 if (likely(port->in_sdio_uart_irq != current))
177 sdio_release_host(port->func);
178}
179
180static inline unsigned int sdio_in(struct sdio_uart_port *port, int offset)
181{
182 unsigned char c;
183 c = sdio_readb(port->func, port->regs_offset + offset, NULL);
184 return c;
185}
186
187static inline void sdio_out(struct sdio_uart_port *port, int offset, int value)
188{
189 sdio_writeb(port->func, value, port->regs_offset + offset, NULL);
190}
191
192static unsigned int sdio_uart_get_mctrl(struct sdio_uart_port *port)
193{
194 unsigned char status;
195 unsigned int ret;
196
197 /* FIXME: What stops this losing the delta bits and breaking
198 sdio_uart_check_modem_status ? */
199 status = sdio_in(port, UART_MSR);
200
201 ret = 0;
202 if (status & UART_MSR_DCD)
203 ret |= TIOCM_CAR;
204 if (status & UART_MSR_RI)
205 ret |= TIOCM_RNG;
206 if (status & UART_MSR_DSR)
207 ret |= TIOCM_DSR;
208 if (status & UART_MSR_CTS)
209 ret |= TIOCM_CTS;
210 return ret;
211}
212
213static void sdio_uart_write_mctrl(struct sdio_uart_port *port,
214 unsigned int mctrl)
215{
216 unsigned char mcr = 0;
217
218 if (mctrl & TIOCM_RTS)
219 mcr |= UART_MCR_RTS;
220 if (mctrl & TIOCM_DTR)
221 mcr |= UART_MCR_DTR;
222 if (mctrl & TIOCM_OUT1)
223 mcr |= UART_MCR_OUT1;
224 if (mctrl & TIOCM_OUT2)
225 mcr |= UART_MCR_OUT2;
226 if (mctrl & TIOCM_LOOP)
227 mcr |= UART_MCR_LOOP;
228
229 sdio_out(port, UART_MCR, mcr);
230}
231
232static inline void sdio_uart_update_mctrl(struct sdio_uart_port *port,
233 unsigned int set, unsigned int clear)
234{
235 unsigned int old;
236
237 old = port->mctrl;
238 port->mctrl = (old & ~clear) | set;
239 if (old != port->mctrl)
240 sdio_uart_write_mctrl(port, port->mctrl);
241}
242
243#define sdio_uart_set_mctrl(port, x) sdio_uart_update_mctrl(port, x, 0)
244#define sdio_uart_clear_mctrl(port, x) sdio_uart_update_mctrl(port, 0, x)
245
246static void sdio_uart_change_speed(struct sdio_uart_port *port,
247 struct ktermios *termios,
248 struct ktermios *old)
249{
250 unsigned char cval, fcr = 0;
251 unsigned int baud, quot;
252
253 switch (termios->c_cflag & CSIZE) {
254 case CS5:
255 cval = UART_LCR_WLEN5;
256 break;
257 case CS6:
258 cval = UART_LCR_WLEN6;
259 break;
260 case CS7:
261 cval = UART_LCR_WLEN7;
262 break;
263 default:
264 case CS8:
265 cval = UART_LCR_WLEN8;
266 break;
267 }
268
269 if (termios->c_cflag & CSTOPB)
270 cval |= UART_LCR_STOP;
271 if (termios->c_cflag & PARENB)
272 cval |= UART_LCR_PARITY;
273 if (!(termios->c_cflag & PARODD))
274 cval |= UART_LCR_EPAR;
275
276 for (;;) {
277 baud = tty_termios_baud_rate(termios);
278 if (baud == 0)
279 baud = 9600; /* Special case: B0 rate. */
280 if (baud <= port->uartclk)
281 break;
282 /*
283 * Oops, the quotient was zero. Try again with the old
284 * baud rate if possible, otherwise default to 9600.
285 */
286 termios->c_cflag &= ~CBAUD;
287 if (old) {
288 termios->c_cflag |= old->c_cflag & CBAUD;
289 old = NULL;
290 } else
291 termios->c_cflag |= B9600;
292 }
293 quot = (2 * port->uartclk + baud) / (2 * baud);
294
295 if (baud < 2400)
296 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
297 else
298 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
299
300 port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
301 if (termios->c_iflag & INPCK)
302 port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
303 if (termios->c_iflag & (BRKINT | PARMRK))
304 port->read_status_mask |= UART_LSR_BI;
305
306 /*
307 * Characters to ignore
308 */
309 port->ignore_status_mask = 0;
310 if (termios->c_iflag & IGNPAR)
311 port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
312 if (termios->c_iflag & IGNBRK) {
313 port->ignore_status_mask |= UART_LSR_BI;
314 /*
315 * If we're ignoring parity and break indicators,
316 * ignore overruns too (for real raw support).
317 */
318 if (termios->c_iflag & IGNPAR)
319 port->ignore_status_mask |= UART_LSR_OE;
320 }
321
322 /*
323 * ignore all characters if CREAD is not set
324 */
325 if ((termios->c_cflag & CREAD) == 0)
326 port->ignore_status_mask |= UART_LSR_DR;
327
328 /*
329 * CTS flow control flag and modem status interrupts
330 */
331 port->ier &= ~UART_IER_MSI;
332 if ((termios->c_cflag & CRTSCTS) || !(termios->c_cflag & CLOCAL))
333 port->ier |= UART_IER_MSI;
334
335 port->lcr = cval;
336
337 sdio_out(port, UART_IER, port->ier);
338 sdio_out(port, UART_LCR, cval | UART_LCR_DLAB);
339 sdio_out(port, UART_DLL, quot & 0xff);
340 sdio_out(port, UART_DLM, quot >> 8);
341 sdio_out(port, UART_LCR, cval);
342 sdio_out(port, UART_FCR, fcr);
343
344 sdio_uart_write_mctrl(port, port->mctrl);
345}
346
347static void sdio_uart_start_tx(struct sdio_uart_port *port)
348{
349 if (!(port->ier & UART_IER_THRI)) {
350 port->ier |= UART_IER_THRI;
351 sdio_out(port, UART_IER, port->ier);
352 }
353}
354
355static void sdio_uart_stop_tx(struct sdio_uart_port *port)
356{
357 if (port->ier & UART_IER_THRI) {
358 port->ier &= ~UART_IER_THRI;
359 sdio_out(port, UART_IER, port->ier);
360 }
361}
362
363static void sdio_uart_stop_rx(struct sdio_uart_port *port)
364{
365 port->ier &= ~UART_IER_RLSI;
366 port->read_status_mask &= ~UART_LSR_DR;
367 sdio_out(port, UART_IER, port->ier);
368}
369
370static void sdio_uart_receive_chars(struct sdio_uart_port *port,
371 unsigned int *status)
372{
373 unsigned int ch, flag;
374 int max_count = 256;
375
376 do {
377 ch = sdio_in(port, UART_RX);
378 flag = TTY_NORMAL;
379 port->icount.rx++;
380
381 if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
382 UART_LSR_FE | UART_LSR_OE))) {
383 /*
384 * For statistics only
385 */
386 if (*status & UART_LSR_BI) {
387 *status &= ~(UART_LSR_FE | UART_LSR_PE);
388 port->icount.brk++;
389 } else if (*status & UART_LSR_PE)
390 port->icount.parity++;
391 else if (*status & UART_LSR_FE)
392 port->icount.frame++;
393 if (*status & UART_LSR_OE)
394 port->icount.overrun++;
395
396 /*
397 * Mask off conditions which should be ignored.
398 */
399 *status &= port->read_status_mask;
400 if (*status & UART_LSR_BI)
401 flag = TTY_BREAK;
402 else if (*status & UART_LSR_PE)
403 flag = TTY_PARITY;
404 else if (*status & UART_LSR_FE)
405 flag = TTY_FRAME;
406 }
407
408 if ((*status & port->ignore_status_mask & ~UART_LSR_OE) == 0)
409 tty_insert_flip_char(&port->port, ch, flag);
410
411 /*
412 * Overrun is special. Since it's reported immediately,
413 * it doesn't affect the current character.
414 */
415 if (*status & ~port->ignore_status_mask & UART_LSR_OE)
416 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
417
418 *status = sdio_in(port, UART_LSR);
419 } while ((*status & UART_LSR_DR) && (max_count-- > 0));
420
421 tty_flip_buffer_push(&port->port);
422}
423
424static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
425{
426 struct kfifo *xmit = &port->xmit_fifo;
427 int count;
428 struct tty_struct *tty;
429 u8 iobuf[16];
430 int len;
431
432 if (port->x_char) {
433 sdio_out(port, UART_TX, port->x_char);
434 port->icount.tx++;
435 port->x_char = 0;
436 return;
437 }
438
439 tty = tty_port_tty_get(&port->port);
440
441 if (tty == NULL || !kfifo_len(xmit) ||
442 tty->stopped || tty->hw_stopped) {
443 sdio_uart_stop_tx(port);
444 tty_kref_put(tty);
445 return;
446 }
447
448 len = kfifo_out_locked(xmit, iobuf, 16, &port->write_lock);
449 for (count = 0; count < len; count++) {
450 sdio_out(port, UART_TX, iobuf[count]);
451 port->icount.tx++;
452 }
453
454 len = kfifo_len(xmit);
455 if (len < WAKEUP_CHARS) {
456 tty_wakeup(tty);
457 if (len == 0)
458 sdio_uart_stop_tx(port);
459 }
460 tty_kref_put(tty);
461}
462
463static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
464{
465 int status;
466 struct tty_struct *tty;
467
468 status = sdio_in(port, UART_MSR);
469
470 if ((status & UART_MSR_ANY_DELTA) == 0)
471 return;
472
473 if (status & UART_MSR_TERI)
474 port->icount.rng++;
475 if (status & UART_MSR_DDSR)
476 port->icount.dsr++;
477 if (status & UART_MSR_DDCD) {
478 port->icount.dcd++;
479 /* DCD raise - wake for open */
480 if (status & UART_MSR_DCD)
481 wake_up_interruptible(&port->port.open_wait);
482 else {
483 /* DCD drop - hang up if tty attached */
484 tty_port_tty_hangup(&port->port, false);
485 }
486 }
487 if (status & UART_MSR_DCTS) {
488 port->icount.cts++;
489 tty = tty_port_tty_get(&port->port);
490 if (tty && C_CRTSCTS(tty)) {
491 int cts = (status & UART_MSR_CTS);
492 if (tty->hw_stopped) {
493 if (cts) {
494 tty->hw_stopped = 0;
495 sdio_uart_start_tx(port);
496 tty_wakeup(tty);
497 }
498 } else {
499 if (!cts) {
500 tty->hw_stopped = 1;
501 sdio_uart_stop_tx(port);
502 }
503 }
504 }
505 tty_kref_put(tty);
506 }
507}
508
509/*
510 * This handles the interrupt from one port.
511 */
512static void sdio_uart_irq(struct sdio_func *func)
513{
514 struct sdio_uart_port *port = sdio_get_drvdata(func);
515 unsigned int iir, lsr;
516
517 /*
518 * In a few places sdio_uart_irq() is called directly instead of
519 * waiting for the actual interrupt to be raised and the SDIO IRQ
520 * thread scheduled in order to reduce latency. However, some
521 * interaction with the tty core may end up calling us back
522 * (serial echo, flow control, etc.) through those same places
523 * causing undesirable effects. Let's stop the recursion here.
524 */
525 if (unlikely(port->in_sdio_uart_irq == current))
526 return;
527
528 iir = sdio_in(port, UART_IIR);
529 if (iir & UART_IIR_NO_INT)
530 return;
531
532 port->in_sdio_uart_irq = current;
533 lsr = sdio_in(port, UART_LSR);
534 if (lsr & UART_LSR_DR)
535 sdio_uart_receive_chars(port, &lsr);
536 sdio_uart_check_modem_status(port);
537 if (lsr & UART_LSR_THRE)
538 sdio_uart_transmit_chars(port);
539 port->in_sdio_uart_irq = NULL;
540}
541
542static int uart_carrier_raised(struct tty_port *tport)
543{
544 struct sdio_uart_port *port =
545 container_of(tport, struct sdio_uart_port, port);
546 unsigned int ret = sdio_uart_claim_func(port);
547 if (ret) /* Missing hardware shouldn't block for carrier */
548 return 1;
549 ret = sdio_uart_get_mctrl(port);
550 sdio_uart_release_func(port);
551 if (ret & TIOCM_CAR)
552 return 1;
553 return 0;
554}
555
556/**
557 * uart_dtr_rts - port helper to set uart signals
558 * @tport: tty port to be updated
559 * @onoff: set to turn on DTR/RTS
560 *
561 * Called by the tty port helpers when the modem signals need to be
562 * adjusted during an open, close and hangup.
563 */
564
565static void uart_dtr_rts(struct tty_port *tport, int onoff)
566{
567 struct sdio_uart_port *port =
568 container_of(tport, struct sdio_uart_port, port);
569 int ret = sdio_uart_claim_func(port);
570 if (ret)
571 return;
572 if (onoff == 0)
573 sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
574 else
575 sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
576 sdio_uart_release_func(port);
577}
578
579/**
580 * sdio_uart_activate - start up hardware
581 * @tport: tty port to activate
582 * @tty: tty bound to this port
583 *
584 * Activate a tty port. The port locking guarantees us this will be
585 * run exactly once per set of opens, and if successful will see the
586 * shutdown method run exactly once to match. Start up and shutdown are
587 * protected from each other by the internal locking and will not run
588 * at the same time even during a hangup event.
589 *
590 * If we successfully start up the port we take an extra kref as we
591 * will keep it around until shutdown when the kref is dropped.
592 */
593
594static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
595{
596 struct sdio_uart_port *port =
597 container_of(tport, struct sdio_uart_port, port);
598 int ret;
599
600 /*
601 * Set the TTY IO error marker - we will only clear this
602 * once we have successfully opened the port.
603 */
604 set_bit(TTY_IO_ERROR, &tty->flags);
605
606 kfifo_reset(&port->xmit_fifo);
607
608 ret = sdio_uart_claim_func(port);
609 if (ret)
610 return ret;
611 ret = sdio_enable_func(port->func);
612 if (ret)
613 goto err1;
614 ret = sdio_claim_irq(port->func, sdio_uart_irq);
615 if (ret)
616 goto err2;
617
618 /*
619 * Clear the FIFO buffers and disable them.
620 * (they will be reenabled in sdio_change_speed())
621 */
622 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
623 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
624 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
625 sdio_out(port, UART_FCR, 0);
626
627 /*
628 * Clear the interrupt registers.
629 */
630 (void) sdio_in(port, UART_LSR);
631 (void) sdio_in(port, UART_RX);
632 (void) sdio_in(port, UART_IIR);
633 (void) sdio_in(port, UART_MSR);
634
635 /*
636 * Now, initialize the UART
637 */
638 sdio_out(port, UART_LCR, UART_LCR_WLEN8);
639
640 port->ier = UART_IER_RLSI|UART_IER_RDI|UART_IER_RTOIE|UART_IER_UUE;
641 port->mctrl = TIOCM_OUT2;
642
643 sdio_uart_change_speed(port, &tty->termios, NULL);
644
645 if (C_BAUD(tty))
646 sdio_uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
647
648 if (C_CRTSCTS(tty))
649 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS))
650 tty->hw_stopped = 1;
651
652 clear_bit(TTY_IO_ERROR, &tty->flags);
653
654 /* Kick the IRQ handler once while we're still holding the host lock */
655 sdio_uart_irq(port->func);
656
657 sdio_uart_release_func(port);
658 return 0;
659
660err2:
661 sdio_disable_func(port->func);
662err1:
663 sdio_uart_release_func(port);
664 return ret;
665}
666
667/**
668 * sdio_uart_shutdown - stop hardware
669 * @tport: tty port to shut down
670 *
671 * Deactivate a tty port. The port locking guarantees us this will be
672 * run only if a successful matching activate already ran. The two are
673 * protected from each other by the internal locking and will not run
674 * at the same time even during a hangup event.
675 */
676
677static void sdio_uart_shutdown(struct tty_port *tport)
678{
679 struct sdio_uart_port *port =
680 container_of(tport, struct sdio_uart_port, port);
681 int ret;
682
683 ret = sdio_uart_claim_func(port);
684 if (ret)
685 return;
686
687 sdio_uart_stop_rx(port);
688
689 /* Disable interrupts from this port */
690 sdio_release_irq(port->func);
691 port->ier = 0;
692 sdio_out(port, UART_IER, 0);
693
694 sdio_uart_clear_mctrl(port, TIOCM_OUT2);
695
696 /* Disable break condition and FIFOs. */
697 port->lcr &= ~UART_LCR_SBC;
698 sdio_out(port, UART_LCR, port->lcr);
699 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
700 UART_FCR_CLEAR_RCVR |
701 UART_FCR_CLEAR_XMIT);
702 sdio_out(port, UART_FCR, 0);
703
704 sdio_disable_func(port->func);
705
706 sdio_uart_release_func(port);
707}
708
709static void sdio_uart_port_destroy(struct tty_port *tport)
710{
711 struct sdio_uart_port *port =
712 container_of(tport, struct sdio_uart_port, port);
713 kfifo_free(&port->xmit_fifo);
714 kfree(port);
715}
716
717/**
718 * sdio_uart_install - install method
719 * @driver: the driver in use (sdio_uart in our case)
720 * @tty: the tty being bound
721 *
722 * Look up and bind the tty and the driver together. Initialize
723 * any needed private data (in our case the termios)
724 */
725
726static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
727{
728 int idx = tty->index;
729 struct sdio_uart_port *port = sdio_uart_port_get(idx);
730 int ret = tty_standard_install(driver, tty);
731
732 if (ret == 0)
733 /* This is the ref sdio_uart_port get provided */
734 tty->driver_data = port;
735 else
736 sdio_uart_port_put(port);
737 return ret;
738}
739
740/**
741 * sdio_uart_cleanup - called on the last tty kref drop
742 * @tty: the tty being destroyed
743 *
744 * Called asynchronously when the last reference to the tty is dropped.
745 * We cannot destroy the tty->driver_data port kref until this point
746 */
747
748static void sdio_uart_cleanup(struct tty_struct *tty)
749{
750 struct sdio_uart_port *port = tty->driver_data;
751 tty->driver_data = NULL; /* Bug trap */
752 sdio_uart_port_put(port);
753}
754
755/*
756 * Open/close/hangup is now entirely boilerplate
757 */
758
759static int sdio_uart_open(struct tty_struct *tty, struct file *filp)
760{
761 struct sdio_uart_port *port = tty->driver_data;
762 return tty_port_open(&port->port, tty, filp);
763}
764
765static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
766{
767 struct sdio_uart_port *port = tty->driver_data;
768 tty_port_close(&port->port, tty, filp);
769}
770
771static void sdio_uart_hangup(struct tty_struct *tty)
772{
773 struct sdio_uart_port *port = tty->driver_data;
774 tty_port_hangup(&port->port);
775}
776
777static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf,
778 int count)
779{
780 struct sdio_uart_port *port = tty->driver_data;
781 int ret;
782
783 if (!port->func)
784 return -ENODEV;
785
786 ret = kfifo_in_locked(&port->xmit_fifo, buf, count, &port->write_lock);
787 if (!(port->ier & UART_IER_THRI)) {
788 int err = sdio_uart_claim_func(port);
789 if (!err) {
790 sdio_uart_start_tx(port);
791 sdio_uart_irq(port->func);
792 sdio_uart_release_func(port);
793 } else
794 ret = err;
795 }
796
797 return ret;
798}
799
800static int sdio_uart_write_room(struct tty_struct *tty)
801{
802 struct sdio_uart_port *port = tty->driver_data;
803 return FIFO_SIZE - kfifo_len(&port->xmit_fifo);
804}
805
806static int sdio_uart_chars_in_buffer(struct tty_struct *tty)
807{
808 struct sdio_uart_port *port = tty->driver_data;
809 return kfifo_len(&port->xmit_fifo);
810}
811
812static void sdio_uart_send_xchar(struct tty_struct *tty, char ch)
813{
814 struct sdio_uart_port *port = tty->driver_data;
815
816 port->x_char = ch;
817 if (ch && !(port->ier & UART_IER_THRI)) {
818 if (sdio_uart_claim_func(port) != 0)
819 return;
820 sdio_uart_start_tx(port);
821 sdio_uart_irq(port->func);
822 sdio_uart_release_func(port);
823 }
824}
825
826static void sdio_uart_throttle(struct tty_struct *tty)
827{
828 struct sdio_uart_port *port = tty->driver_data;
829
830 if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
831 return;
832
833 if (sdio_uart_claim_func(port) != 0)
834 return;
835
836 if (I_IXOFF(tty)) {
837 port->x_char = STOP_CHAR(tty);
838 sdio_uart_start_tx(port);
839 }
840
841 if (C_CRTSCTS(tty))
842 sdio_uart_clear_mctrl(port, TIOCM_RTS);
843
844 sdio_uart_irq(port->func);
845 sdio_uart_release_func(port);
846}
847
848static void sdio_uart_unthrottle(struct tty_struct *tty)
849{
850 struct sdio_uart_port *port = tty->driver_data;
851
852 if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
853 return;
854
855 if (sdio_uart_claim_func(port) != 0)
856 return;
857
858 if (I_IXOFF(tty)) {
859 if (port->x_char) {
860 port->x_char = 0;
861 } else {
862 port->x_char = START_CHAR(tty);
863 sdio_uart_start_tx(port);
864 }
865 }
866
867 if (C_CRTSCTS(tty))
868 sdio_uart_set_mctrl(port, TIOCM_RTS);
869
870 sdio_uart_irq(port->func);
871 sdio_uart_release_func(port);
872}
873
874static void sdio_uart_set_termios(struct tty_struct *tty,
875 struct ktermios *old_termios)
876{
877 struct sdio_uart_port *port = tty->driver_data;
878 unsigned int cflag = tty->termios.c_cflag;
879
880 if (sdio_uart_claim_func(port) != 0)
881 return;
882
883 sdio_uart_change_speed(port, &tty->termios, old_termios);
884
885 /* Handle transition to B0 status */
886 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
887 sdio_uart_clear_mctrl(port, TIOCM_RTS | TIOCM_DTR);
888
889 /* Handle transition away from B0 status */
890 if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
891 unsigned int mask = TIOCM_DTR;
892 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
893 mask |= TIOCM_RTS;
894 sdio_uart_set_mctrl(port, mask);
895 }
896
897 /* Handle turning off CRTSCTS */
898 if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
899 tty->hw_stopped = 0;
900 sdio_uart_start_tx(port);
901 }
902
903 /* Handle turning on CRTSCTS */
904 if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
905 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS)) {
906 tty->hw_stopped = 1;
907 sdio_uart_stop_tx(port);
908 }
909 }
910
911 sdio_uart_release_func(port);
912}
913
914static int sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
915{
916 struct sdio_uart_port *port = tty->driver_data;
917 int result;
918
919 result = sdio_uart_claim_func(port);
920 if (result != 0)
921 return result;
922
923 if (break_state == -1)
924 port->lcr |= UART_LCR_SBC;
925 else
926 port->lcr &= ~UART_LCR_SBC;
927 sdio_out(port, UART_LCR, port->lcr);
928
929 sdio_uart_release_func(port);
930 return 0;
931}
932
933static int sdio_uart_tiocmget(struct tty_struct *tty)
934{
935 struct sdio_uart_port *port = tty->driver_data;
936 int result;
937
938 result = sdio_uart_claim_func(port);
939 if (!result) {
940 result = port->mctrl | sdio_uart_get_mctrl(port);
941 sdio_uart_release_func(port);
942 }
943
944 return result;
945}
946
947static int sdio_uart_tiocmset(struct tty_struct *tty,
948 unsigned int set, unsigned int clear)
949{
950 struct sdio_uart_port *port = tty->driver_data;
951 int result;
952
953 result = sdio_uart_claim_func(port);
954 if (!result) {
955 sdio_uart_update_mctrl(port, set, clear);
956 sdio_uart_release_func(port);
957 }
958
959 return result;
960}
961
962static int sdio_uart_proc_show(struct seq_file *m, void *v)
963{
964 int i;
965
966 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n",
967 "", "", "");
968 for (i = 0; i < UART_NR; i++) {
969 struct sdio_uart_port *port = sdio_uart_port_get(i);
970 if (port) {
971 seq_printf(m, "%d: uart:SDIO", i);
972 if (capable(CAP_SYS_ADMIN)) {
973 seq_printf(m, " tx:%d rx:%d",
974 port->icount.tx, port->icount.rx);
975 if (port->icount.frame)
976 seq_printf(m, " fe:%d",
977 port->icount.frame);
978 if (port->icount.parity)
979 seq_printf(m, " pe:%d",
980 port->icount.parity);
981 if (port->icount.brk)
982 seq_printf(m, " brk:%d",
983 port->icount.brk);
984 if (port->icount.overrun)
985 seq_printf(m, " oe:%d",
986 port->icount.overrun);
987 if (port->icount.cts)
988 seq_printf(m, " cts:%d",
989 port->icount.cts);
990 if (port->icount.dsr)
991 seq_printf(m, " dsr:%d",
992 port->icount.dsr);
993 if (port->icount.rng)
994 seq_printf(m, " rng:%d",
995 port->icount.rng);
996 if (port->icount.dcd)
997 seq_printf(m, " dcd:%d",
998 port->icount.dcd);
999 }
1000 sdio_uart_port_put(port);
1001 seq_putc(m, '\n');
1002 }
1003 }
1004 return 0;
1005}
1006
1007static const struct tty_port_operations sdio_uart_port_ops = {
1008 .dtr_rts = uart_dtr_rts,
1009 .carrier_raised = uart_carrier_raised,
1010 .shutdown = sdio_uart_shutdown,
1011 .activate = sdio_uart_activate,
1012 .destruct = sdio_uart_port_destroy,
1013};
1014
1015static const struct tty_operations sdio_uart_ops = {
1016 .open = sdio_uart_open,
1017 .close = sdio_uart_close,
1018 .write = sdio_uart_write,
1019 .write_room = sdio_uart_write_room,
1020 .chars_in_buffer = sdio_uart_chars_in_buffer,
1021 .send_xchar = sdio_uart_send_xchar,
1022 .throttle = sdio_uart_throttle,
1023 .unthrottle = sdio_uart_unthrottle,
1024 .set_termios = sdio_uart_set_termios,
1025 .hangup = sdio_uart_hangup,
1026 .break_ctl = sdio_uart_break_ctl,
1027 .tiocmget = sdio_uart_tiocmget,
1028 .tiocmset = sdio_uart_tiocmset,
1029 .install = sdio_uart_install,
1030 .cleanup = sdio_uart_cleanup,
1031 .proc_show = sdio_uart_proc_show,
1032};
1033
1034static struct tty_driver *sdio_uart_tty_driver;
1035
1036static int sdio_uart_probe(struct sdio_func *func,
1037 const struct sdio_device_id *id)
1038{
1039 struct sdio_uart_port *port;
1040 int ret;
1041
1042 port = kzalloc(sizeof(struct sdio_uart_port), GFP_KERNEL);
1043 if (!port)
1044 return -ENOMEM;
1045
1046 if (func->class == SDIO_CLASS_UART) {
1047 pr_warn("%s: need info on UART class basic setup\n",
1048 sdio_func_id(func));
1049 kfree(port);
1050 return -ENOSYS;
1051 } else if (func->class == SDIO_CLASS_GPS) {
1052 /*
1053 * We need tuple 0x91. It contains SUBTPL_SIOREG
1054 * and SUBTPL_RCVCAPS.
1055 */
1056 struct sdio_func_tuple *tpl;
1057 for (tpl = func->tuples; tpl; tpl = tpl->next) {
1058 if (tpl->code != 0x91)
1059 continue;
1060 if (tpl->size < 10)
1061 continue;
1062 if (tpl->data[1] == 0) /* SUBTPL_SIOREG */
1063 break;
1064 }
1065 if (!tpl) {
1066 pr_warn("%s: can't find tuple 0x91 subtuple 0 (SUBTPL_SIOREG) for GPS class\n",
1067 sdio_func_id(func));
1068 kfree(port);
1069 return -EINVAL;
1070 }
1071 pr_debug("%s: Register ID = 0x%02x, Exp ID = 0x%02x\n",
1072 sdio_func_id(func), tpl->data[2], tpl->data[3]);
1073 port->regs_offset = (tpl->data[4] << 0) |
1074 (tpl->data[5] << 8) |
1075 (tpl->data[6] << 16);
1076 pr_debug("%s: regs offset = 0x%x\n",
1077 sdio_func_id(func), port->regs_offset);
1078 port->uartclk = tpl->data[7] * 115200;
1079 if (port->uartclk == 0)
1080 port->uartclk = 115200;
1081 pr_debug("%s: clk %d baudcode %u 4800-div %u\n",
1082 sdio_func_id(func), port->uartclk,
1083 tpl->data[7], tpl->data[8] | (tpl->data[9] << 8));
1084 } else {
1085 kfree(port);
1086 return -EINVAL;
1087 }
1088
1089 port->func = func;
1090 sdio_set_drvdata(func, port);
1091 tty_port_init(&port->port);
1092 port->port.ops = &sdio_uart_port_ops;
1093
1094 ret = sdio_uart_add_port(port);
1095 if (ret) {
1096 kfree(port);
1097 } else {
1098 struct device *dev;
1099 dev = tty_port_register_device(&port->port,
1100 sdio_uart_tty_driver, port->index, &func->dev);
1101 if (IS_ERR(dev)) {
1102 sdio_uart_port_remove(port);
1103 ret = PTR_ERR(dev);
1104 }
1105 }
1106
1107 return ret;
1108}
1109
1110static void sdio_uart_remove(struct sdio_func *func)
1111{
1112 struct sdio_uart_port *port = sdio_get_drvdata(func);
1113
1114 tty_unregister_device(sdio_uart_tty_driver, port->index);
1115 sdio_uart_port_remove(port);
1116}
1117
1118static const struct sdio_device_id sdio_uart_ids[] = {
1119 { SDIO_DEVICE_CLASS(SDIO_CLASS_UART) },
1120 { SDIO_DEVICE_CLASS(SDIO_CLASS_GPS) },
1121 { /* end: all zeroes */ },
1122};
1123
1124MODULE_DEVICE_TABLE(sdio, sdio_uart_ids);
1125
1126static struct sdio_driver sdio_uart_driver = {
1127 .probe = sdio_uart_probe,
1128 .remove = sdio_uart_remove,
1129 .name = "sdio_uart",
1130 .id_table = sdio_uart_ids,
1131};
1132
1133static int __init sdio_uart_init(void)
1134{
1135 int ret;
1136 struct tty_driver *tty_drv;
1137
1138 sdio_uart_tty_driver = tty_drv = alloc_tty_driver(UART_NR);
1139 if (!tty_drv)
1140 return -ENOMEM;
1141
1142 tty_drv->driver_name = "sdio_uart";
1143 tty_drv->name = "ttySDIO";
1144 tty_drv->major = 0; /* dynamically allocated */
1145 tty_drv->minor_start = 0;
1146 tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
1147 tty_drv->subtype = SERIAL_TYPE_NORMAL;
1148 tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
1149 tty_drv->init_termios = tty_std_termios;
1150 tty_drv->init_termios.c_cflag = B4800 | CS8 | CREAD | HUPCL | CLOCAL;
1151 tty_drv->init_termios.c_ispeed = 4800;
1152 tty_drv->init_termios.c_ospeed = 4800;
1153 tty_set_operations(tty_drv, &sdio_uart_ops);
1154
1155 ret = tty_register_driver(tty_drv);
1156 if (ret)
1157 goto err1;
1158
1159 ret = sdio_register_driver(&sdio_uart_driver);
1160 if (ret)
1161 goto err2;
1162
1163 return 0;
1164
1165err2:
1166 tty_unregister_driver(tty_drv);
1167err1:
1168 put_tty_driver(tty_drv);
1169 return ret;
1170}
1171
1172static void __exit sdio_uart_exit(void)
1173{
1174 sdio_unregister_driver(&sdio_uart_driver);
1175 tty_unregister_driver(sdio_uart_tty_driver);
1176 put_tty_driver(sdio_uart_tty_driver);
1177}
1178
1179module_init(sdio_uart_init);
1180module_exit(sdio_uart_exit);
1181
1182MODULE_AUTHOR("Nicolas Pitre");
1183MODULE_LICENSE("GPL");