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Merge tag 'mm-hotfixes-stable-2025-07-11-16-16' of git://git.kernel.org/pub/scm/linux...
[linux-block.git] / drivers / mmc / core / sdio_uart.c
... / ...
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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.h>
32#include <linux/serial_reg.h>
33#include <linux/circ_buf.h>
34#include <linux/tty.h>
35#include <linux/tty_flip.h>
36#include <linux/kfifo.h>
37#include <linux/slab.h>
38
39#include <linux/mmc/core.h>
40#include <linux/mmc/card.h>
41#include <linux/mmc/sdio_func.h>
42#include <linux/mmc/sdio_ids.h>
43
44
45#define UART_NR 8 /* Number of UARTs this driver can handle */
46
47
48#define FIFO_SIZE PAGE_SIZE
49#define WAKEUP_CHARS 256
50
51struct uart_icount {
52 __u32 cts;
53 __u32 dsr;
54 __u32 rng;
55 __u32 dcd;
56 __u32 rx;
57 __u32 tx;
58 __u32 frame;
59 __u32 overrun;
60 __u32 parity;
61 __u32 brk;
62};
63
64struct sdio_uart_port {
65 struct tty_port port;
66 unsigned int index;
67 struct sdio_func *func;
68 struct mutex func_lock;
69 struct task_struct *in_sdio_uart_irq;
70 unsigned int regs_offset;
71 struct kfifo xmit_fifo;
72 spinlock_t write_lock;
73 struct uart_icount icount;
74 unsigned int uartclk;
75 unsigned int mctrl;
76 unsigned int rx_mctrl;
77 unsigned int read_status_mask;
78 unsigned int ignore_status_mask;
79 unsigned char x_char;
80 unsigned char ier;
81 unsigned char lcr;
82};
83
84static struct sdio_uart_port *sdio_uart_table[UART_NR];
85static DEFINE_SPINLOCK(sdio_uart_table_lock);
86
87static int sdio_uart_add_port(struct sdio_uart_port *port)
88{
89 int index, ret = -EBUSY;
90
91 mutex_init(&port->func_lock);
92 spin_lock_init(&port->write_lock);
93 if (kfifo_alloc(&port->xmit_fifo, FIFO_SIZE, GFP_KERNEL))
94 return -ENOMEM;
95
96 spin_lock(&sdio_uart_table_lock);
97 for (index = 0; index < UART_NR; index++) {
98 if (!sdio_uart_table[index]) {
99 port->index = index;
100 sdio_uart_table[index] = port;
101 ret = 0;
102 break;
103 }
104 }
105 spin_unlock(&sdio_uart_table_lock);
106
107 return ret;
108}
109
110static struct sdio_uart_port *sdio_uart_port_get(unsigned index)
111{
112 struct sdio_uart_port *port;
113
114 if (index >= UART_NR)
115 return NULL;
116
117 spin_lock(&sdio_uart_table_lock);
118 port = sdio_uart_table[index];
119 if (port)
120 tty_port_get(&port->port);
121 spin_unlock(&sdio_uart_table_lock);
122
123 return port;
124}
125
126static void sdio_uart_port_put(struct sdio_uart_port *port)
127{
128 tty_port_put(&port->port);
129}
130
131static void sdio_uart_port_remove(struct sdio_uart_port *port)
132{
133 struct sdio_func *func;
134
135 spin_lock(&sdio_uart_table_lock);
136 sdio_uart_table[port->index] = NULL;
137 spin_unlock(&sdio_uart_table_lock);
138
139 /*
140 * We're killing a port that potentially still is in use by
141 * the tty layer. Be careful to prevent any further access
142 * to the SDIO function and arrange for the tty layer to
143 * give up on that port ASAP.
144 * Beware: the lock ordering is critical.
145 */
146 mutex_lock(&port->port.mutex);
147 mutex_lock(&port->func_lock);
148 func = port->func;
149 sdio_claim_host(func);
150 port->func = NULL;
151 mutex_unlock(&port->func_lock);
152 /* tty_hangup is async so is this safe as is ?? */
153 tty_port_tty_hangup(&port->port, false);
154 mutex_unlock(&port->port.mutex);
155 sdio_release_irq(func);
156 sdio_disable_func(func);
157 sdio_release_host(func);
158
159 sdio_uart_port_put(port);
160}
161
162static int sdio_uart_claim_func(struct sdio_uart_port *port)
163{
164 mutex_lock(&port->func_lock);
165 if (unlikely(!port->func)) {
166 mutex_unlock(&port->func_lock);
167 return -ENODEV;
168 }
169 if (likely(port->in_sdio_uart_irq != current))
170 sdio_claim_host(port->func);
171 mutex_unlock(&port->func_lock);
172 return 0;
173}
174
175static inline void sdio_uart_release_func(struct sdio_uart_port *port)
176{
177 if (likely(port->in_sdio_uart_irq != current))
178 sdio_release_host(port->func);
179}
180
181static inline u8 sdio_in(struct sdio_uart_port *port, int offset)
182{
183 return sdio_readb(port->func, port->regs_offset + offset, NULL);
184}
185
186static inline void sdio_out(struct sdio_uart_port *port, int offset, int value)
187{
188 sdio_writeb(port->func, value, port->regs_offset + offset, NULL);
189}
190
191static unsigned int sdio_uart_get_mctrl(struct sdio_uart_port *port)
192{
193 unsigned int ret;
194 u8 status;
195
196 /* FIXME: What stops this losing the delta bits and breaking
197 sdio_uart_check_modem_status ? */
198 status = sdio_in(port, UART_MSR);
199
200 ret = 0;
201 if (status & UART_MSR_DCD)
202 ret |= TIOCM_CAR;
203 if (status & UART_MSR_RI)
204 ret |= TIOCM_RNG;
205 if (status & UART_MSR_DSR)
206 ret |= TIOCM_DSR;
207 if (status & UART_MSR_CTS)
208 ret |= TIOCM_CTS;
209 return ret;
210}
211
212static void sdio_uart_write_mctrl(struct sdio_uart_port *port,
213 unsigned int mctrl)
214{
215 unsigned char mcr = 0;
216
217 if (mctrl & TIOCM_RTS)
218 mcr |= UART_MCR_RTS;
219 if (mctrl & TIOCM_DTR)
220 mcr |= UART_MCR_DTR;
221 if (mctrl & TIOCM_OUT1)
222 mcr |= UART_MCR_OUT1;
223 if (mctrl & TIOCM_OUT2)
224 mcr |= UART_MCR_OUT2;
225 if (mctrl & TIOCM_LOOP)
226 mcr |= UART_MCR_LOOP;
227
228 sdio_out(port, UART_MCR, mcr);
229}
230
231static inline void sdio_uart_update_mctrl(struct sdio_uart_port *port,
232 unsigned int set, unsigned int clear)
233{
234 unsigned int old;
235
236 old = port->mctrl;
237 port->mctrl = (old & ~clear) | set;
238 if (old != port->mctrl)
239 sdio_uart_write_mctrl(port, port->mctrl);
240}
241
242#define sdio_uart_set_mctrl(port, x) sdio_uart_update_mctrl(port, x, 0)
243#define sdio_uart_clear_mctrl(port, x) sdio_uart_update_mctrl(port, 0, x)
244
245static void sdio_uart_change_speed(struct sdio_uart_port *port,
246 struct ktermios *termios,
247 const struct ktermios *old)
248{
249 unsigned char cval, fcr = 0;
250 unsigned int baud, quot;
251
252 cval = UART_LCR_WLEN(tty_get_char_size(termios->c_cflag));
253
254 if (termios->c_cflag & CSTOPB)
255 cval |= UART_LCR_STOP;
256 if (termios->c_cflag & PARENB)
257 cval |= UART_LCR_PARITY;
258 if (!(termios->c_cflag & PARODD))
259 cval |= UART_LCR_EPAR;
260
261 for (;;) {
262 baud = tty_termios_baud_rate(termios);
263 if (baud == 0)
264 baud = 9600; /* Special case: B0 rate. */
265 if (baud <= port->uartclk)
266 break;
267 /*
268 * Oops, the quotient was zero. Try again with the old
269 * baud rate if possible, otherwise default to 9600.
270 */
271 termios->c_cflag &= ~CBAUD;
272 if (old) {
273 termios->c_cflag |= old->c_cflag & CBAUD;
274 old = NULL;
275 } else
276 termios->c_cflag |= B9600;
277 }
278 quot = (2 * port->uartclk + baud) / (2 * baud);
279
280 if (baud < 2400)
281 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_TRIGGER_1;
282 else
283 fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_10;
284
285 port->read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
286 if (termios->c_iflag & INPCK)
287 port->read_status_mask |= UART_LSR_FE | UART_LSR_PE;
288 if (termios->c_iflag & (BRKINT | PARMRK))
289 port->read_status_mask |= UART_LSR_BI;
290
291 /*
292 * Characters to ignore
293 */
294 port->ignore_status_mask = 0;
295 if (termios->c_iflag & IGNPAR)
296 port->ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
297 if (termios->c_iflag & IGNBRK) {
298 port->ignore_status_mask |= UART_LSR_BI;
299 /*
300 * If we're ignoring parity and break indicators,
301 * ignore overruns too (for real raw support).
302 */
303 if (termios->c_iflag & IGNPAR)
304 port->ignore_status_mask |= UART_LSR_OE;
305 }
306
307 /*
308 * ignore all characters if CREAD is not set
309 */
310 if ((termios->c_cflag & CREAD) == 0)
311 port->ignore_status_mask |= UART_LSR_DR;
312
313 /*
314 * CTS flow control flag and modem status interrupts
315 */
316 port->ier &= ~UART_IER_MSI;
317 if ((termios->c_cflag & CRTSCTS) || !(termios->c_cflag & CLOCAL))
318 port->ier |= UART_IER_MSI;
319
320 port->lcr = cval;
321
322 sdio_out(port, UART_IER, port->ier);
323 sdio_out(port, UART_LCR, cval | UART_LCR_DLAB);
324 sdio_out(port, UART_DLL, quot & 0xff);
325 sdio_out(port, UART_DLM, quot >> 8);
326 sdio_out(port, UART_LCR, cval);
327 sdio_out(port, UART_FCR, fcr);
328
329 sdio_uart_write_mctrl(port, port->mctrl);
330}
331
332static void sdio_uart_start_tx(struct sdio_uart_port *port)
333{
334 if (!(port->ier & UART_IER_THRI)) {
335 port->ier |= UART_IER_THRI;
336 sdio_out(port, UART_IER, port->ier);
337 }
338}
339
340static void sdio_uart_stop_tx(struct sdio_uart_port *port)
341{
342 if (port->ier & UART_IER_THRI) {
343 port->ier &= ~UART_IER_THRI;
344 sdio_out(port, UART_IER, port->ier);
345 }
346}
347
348static void sdio_uart_stop_rx(struct sdio_uart_port *port)
349{
350 port->ier &= ~UART_IER_RLSI;
351 port->read_status_mask &= ~UART_LSR_DR;
352 sdio_out(port, UART_IER, port->ier);
353}
354
355static void sdio_uart_receive_chars(struct sdio_uart_port *port, u8 *status)
356{
357 int max_count = 256;
358
359 do {
360 u8 ch = sdio_in(port, UART_RX);
361 u8 flag = TTY_NORMAL;
362 port->icount.rx++;
363
364 if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
365 UART_LSR_FE | UART_LSR_OE))) {
366 /*
367 * For statistics only
368 */
369 if (*status & UART_LSR_BI) {
370 *status &= ~(UART_LSR_FE | UART_LSR_PE);
371 port->icount.brk++;
372 } else if (*status & UART_LSR_PE)
373 port->icount.parity++;
374 else if (*status & UART_LSR_FE)
375 port->icount.frame++;
376 if (*status & UART_LSR_OE)
377 port->icount.overrun++;
378
379 /*
380 * Mask off conditions which should be ignored.
381 */
382 *status &= port->read_status_mask;
383 if (*status & UART_LSR_BI)
384 flag = TTY_BREAK;
385 else if (*status & UART_LSR_PE)
386 flag = TTY_PARITY;
387 else if (*status & UART_LSR_FE)
388 flag = TTY_FRAME;
389 }
390
391 if ((*status & port->ignore_status_mask & ~UART_LSR_OE) == 0)
392 tty_insert_flip_char(&port->port, ch, flag);
393
394 /*
395 * Overrun is special. Since it's reported immediately,
396 * it doesn't affect the current character.
397 */
398 if (*status & ~port->ignore_status_mask & UART_LSR_OE)
399 tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
400
401 *status = sdio_in(port, UART_LSR);
402 } while ((*status & UART_LSR_DR) && (max_count-- > 0));
403
404 tty_flip_buffer_push(&port->port);
405}
406
407static void sdio_uart_transmit_chars(struct sdio_uart_port *port)
408{
409 struct kfifo *xmit = &port->xmit_fifo;
410 int count;
411 struct tty_struct *tty;
412 u8 iobuf[16];
413 int len;
414
415 if (port->x_char) {
416 sdio_out(port, UART_TX, port->x_char);
417 port->icount.tx++;
418 port->x_char = 0;
419 return;
420 }
421
422 tty = tty_port_tty_get(&port->port);
423
424 if (tty == NULL || !kfifo_len(xmit) ||
425 tty->flow.stopped || tty->hw_stopped) {
426 sdio_uart_stop_tx(port);
427 tty_kref_put(tty);
428 return;
429 }
430
431 len = kfifo_out_locked(xmit, iobuf, 16, &port->write_lock);
432 for (count = 0; count < len; count++) {
433 sdio_out(port, UART_TX, iobuf[count]);
434 port->icount.tx++;
435 }
436
437 len = kfifo_len(xmit);
438 if (len < WAKEUP_CHARS) {
439 tty_wakeup(tty);
440 if (len == 0)
441 sdio_uart_stop_tx(port);
442 }
443 tty_kref_put(tty);
444}
445
446static void sdio_uart_check_modem_status(struct sdio_uart_port *port)
447{
448 struct tty_struct *tty;
449 u8 status;
450
451 status = sdio_in(port, UART_MSR);
452
453 if ((status & UART_MSR_ANY_DELTA) == 0)
454 return;
455
456 if (status & UART_MSR_TERI)
457 port->icount.rng++;
458 if (status & UART_MSR_DDSR)
459 port->icount.dsr++;
460 if (status & UART_MSR_DDCD) {
461 port->icount.dcd++;
462 /* DCD raise - wake for open */
463 if (status & UART_MSR_DCD)
464 wake_up_interruptible(&port->port.open_wait);
465 else {
466 /* DCD drop - hang up if tty attached */
467 tty_port_tty_hangup(&port->port, false);
468 }
469 }
470 if (status & UART_MSR_DCTS) {
471 port->icount.cts++;
472 tty = tty_port_tty_get(&port->port);
473 if (tty && C_CRTSCTS(tty)) {
474 bool cts = status & UART_MSR_CTS;
475 if (tty->hw_stopped) {
476 if (cts) {
477 tty->hw_stopped = false;
478 sdio_uart_start_tx(port);
479 tty_wakeup(tty);
480 }
481 } else {
482 if (!cts) {
483 tty->hw_stopped = true;
484 sdio_uart_stop_tx(port);
485 }
486 }
487 }
488 tty_kref_put(tty);
489 }
490}
491
492/*
493 * This handles the interrupt from one port.
494 */
495static void sdio_uart_irq(struct sdio_func *func)
496{
497 struct sdio_uart_port *port = sdio_get_drvdata(func);
498 u8 iir, lsr;
499
500 /*
501 * In a few places sdio_uart_irq() is called directly instead of
502 * waiting for the actual interrupt to be raised and the SDIO IRQ
503 * thread scheduled in order to reduce latency. However, some
504 * interaction with the tty core may end up calling us back
505 * (serial echo, flow control, etc.) through those same places
506 * causing undesirable effects. Let's stop the recursion here.
507 */
508 if (unlikely(port->in_sdio_uart_irq == current))
509 return;
510
511 iir = sdio_in(port, UART_IIR);
512 if (iir & UART_IIR_NO_INT)
513 return;
514
515 port->in_sdio_uart_irq = current;
516 lsr = sdio_in(port, UART_LSR);
517 if (lsr & UART_LSR_DR)
518 sdio_uart_receive_chars(port, &lsr);
519 sdio_uart_check_modem_status(port);
520 if (lsr & UART_LSR_THRE)
521 sdio_uart_transmit_chars(port);
522 port->in_sdio_uart_irq = NULL;
523}
524
525static bool uart_carrier_raised(struct tty_port *tport)
526{
527 struct sdio_uart_port *port =
528 container_of(tport, struct sdio_uart_port, port);
529 unsigned int ret = sdio_uart_claim_func(port);
530 if (ret) /* Missing hardware shouldn't block for carrier */
531 return 1;
532 ret = sdio_uart_get_mctrl(port);
533 sdio_uart_release_func(port);
534
535 return ret & TIOCM_CAR;
536}
537
538/**
539 * uart_dtr_rts - port helper to set uart signals
540 * @tport: tty port to be updated
541 * @active: set to turn on DTR/RTS
542 *
543 * Called by the tty port helpers when the modem signals need to be
544 * adjusted during an open, close and hangup.
545 */
546
547static void uart_dtr_rts(struct tty_port *tport, bool active)
548{
549 struct sdio_uart_port *port =
550 container_of(tport, struct sdio_uart_port, port);
551 int ret = sdio_uart_claim_func(port);
552 if (ret)
553 return;
554 if (!active)
555 sdio_uart_clear_mctrl(port, TIOCM_DTR | TIOCM_RTS);
556 else
557 sdio_uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS);
558 sdio_uart_release_func(port);
559}
560
561/**
562 * sdio_uart_activate - start up hardware
563 * @tport: tty port to activate
564 * @tty: tty bound to this port
565 *
566 * Activate a tty port. The port locking guarantees us this will be
567 * run exactly once per set of opens, and if successful will see the
568 * shutdown method run exactly once to match. Start up and shutdown are
569 * protected from each other by the internal locking and will not run
570 * at the same time even during a hangup event.
571 *
572 * If we successfully start up the port we take an extra kref as we
573 * will keep it around until shutdown when the kref is dropped.
574 */
575
576static int sdio_uart_activate(struct tty_port *tport, struct tty_struct *tty)
577{
578 struct sdio_uart_port *port =
579 container_of(tport, struct sdio_uart_port, port);
580 int ret;
581
582 /*
583 * Set the TTY IO error marker - we will only clear this
584 * once we have successfully opened the port.
585 */
586 set_bit(TTY_IO_ERROR, &tty->flags);
587
588 kfifo_reset(&port->xmit_fifo);
589
590 ret = sdio_uart_claim_func(port);
591 if (ret)
592 return ret;
593 ret = sdio_enable_func(port->func);
594 if (ret)
595 goto err1;
596 ret = sdio_claim_irq(port->func, sdio_uart_irq);
597 if (ret)
598 goto err2;
599
600 /*
601 * Clear the FIFO buffers and disable them.
602 * (they will be reenabled in sdio_change_speed())
603 */
604 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO);
605 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
606 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
607 sdio_out(port, UART_FCR, 0);
608
609 /*
610 * Clear the interrupt registers.
611 */
612 (void) sdio_in(port, UART_LSR);
613 (void) sdio_in(port, UART_RX);
614 (void) sdio_in(port, UART_IIR);
615 (void) sdio_in(port, UART_MSR);
616
617 /*
618 * Now, initialize the UART
619 */
620 sdio_out(port, UART_LCR, UART_LCR_WLEN8);
621
622 port->ier = UART_IER_RLSI|UART_IER_RDI|UART_IER_RTOIE|UART_IER_UUE;
623 port->mctrl = TIOCM_OUT2;
624
625 sdio_uart_change_speed(port, &tty->termios, NULL);
626
627 if (C_BAUD(tty))
628 sdio_uart_set_mctrl(port, TIOCM_RTS | TIOCM_DTR);
629
630 if (C_CRTSCTS(tty))
631 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS))
632 tty->hw_stopped = true;
633
634 clear_bit(TTY_IO_ERROR, &tty->flags);
635
636 /* Kick the IRQ handler once while we're still holding the host lock */
637 sdio_uart_irq(port->func);
638
639 sdio_uart_release_func(port);
640 return 0;
641
642err2:
643 sdio_disable_func(port->func);
644err1:
645 sdio_uart_release_func(port);
646 return ret;
647}
648
649/**
650 * sdio_uart_shutdown - stop hardware
651 * @tport: tty port to shut down
652 *
653 * Deactivate a tty port. The port locking guarantees us this will be
654 * run only if a successful matching activate already ran. The two are
655 * protected from each other by the internal locking and will not run
656 * at the same time even during a hangup event.
657 */
658
659static void sdio_uart_shutdown(struct tty_port *tport)
660{
661 struct sdio_uart_port *port =
662 container_of(tport, struct sdio_uart_port, port);
663 int ret;
664
665 ret = sdio_uart_claim_func(port);
666 if (ret)
667 return;
668
669 sdio_uart_stop_rx(port);
670
671 /* Disable interrupts from this port */
672 sdio_release_irq(port->func);
673 port->ier = 0;
674 sdio_out(port, UART_IER, 0);
675
676 sdio_uart_clear_mctrl(port, TIOCM_OUT2);
677
678 /* Disable break condition and FIFOs. */
679 port->lcr &= ~UART_LCR_SBC;
680 sdio_out(port, UART_LCR, port->lcr);
681 sdio_out(port, UART_FCR, UART_FCR_ENABLE_FIFO |
682 UART_FCR_CLEAR_RCVR |
683 UART_FCR_CLEAR_XMIT);
684 sdio_out(port, UART_FCR, 0);
685
686 sdio_disable_func(port->func);
687
688 sdio_uart_release_func(port);
689}
690
691static void sdio_uart_port_destroy(struct tty_port *tport)
692{
693 struct sdio_uart_port *port =
694 container_of(tport, struct sdio_uart_port, port);
695 kfifo_free(&port->xmit_fifo);
696 kfree(port);
697}
698
699/**
700 * sdio_uart_install - install method
701 * @driver: the driver in use (sdio_uart in our case)
702 * @tty: the tty being bound
703 *
704 * Look up and bind the tty and the driver together. Initialize
705 * any needed private data (in our case the termios)
706 */
707
708static int sdio_uart_install(struct tty_driver *driver, struct tty_struct *tty)
709{
710 int idx = tty->index;
711 struct sdio_uart_port *port = sdio_uart_port_get(idx);
712 int ret = tty_standard_install(driver, tty);
713
714 if (ret == 0)
715 /* This is the ref sdio_uart_port get provided */
716 tty->driver_data = port;
717 else
718 sdio_uart_port_put(port);
719 return ret;
720}
721
722/**
723 * sdio_uart_cleanup - called on the last tty kref drop
724 * @tty: the tty being destroyed
725 *
726 * Called asynchronously when the last reference to the tty is dropped.
727 * We cannot destroy the tty->driver_data port kref until this point
728 */
729
730static void sdio_uart_cleanup(struct tty_struct *tty)
731{
732 struct sdio_uart_port *port = tty->driver_data;
733 tty->driver_data = NULL; /* Bug trap */
734 sdio_uart_port_put(port);
735}
736
737/*
738 * Open/close/hangup is now entirely boilerplate
739 */
740
741static int sdio_uart_open(struct tty_struct *tty, struct file *filp)
742{
743 struct sdio_uart_port *port = tty->driver_data;
744 return tty_port_open(&port->port, tty, filp);
745}
746
747static void sdio_uart_close(struct tty_struct *tty, struct file * filp)
748{
749 struct sdio_uart_port *port = tty->driver_data;
750 tty_port_close(&port->port, tty, filp);
751}
752
753static void sdio_uart_hangup(struct tty_struct *tty)
754{
755 struct sdio_uart_port *port = tty->driver_data;
756 tty_port_hangup(&port->port);
757}
758
759static ssize_t sdio_uart_write(struct tty_struct *tty, const u8 *buf,
760 size_t count)
761{
762 struct sdio_uart_port *port = tty->driver_data;
763 int ret;
764
765 if (!port->func)
766 return -ENODEV;
767
768 ret = kfifo_in_locked(&port->xmit_fifo, buf, count, &port->write_lock);
769 if (!(port->ier & UART_IER_THRI)) {
770 int err = sdio_uart_claim_func(port);
771 if (!err) {
772 sdio_uart_start_tx(port);
773 sdio_uart_irq(port->func);
774 sdio_uart_release_func(port);
775 } else
776 ret = err;
777 }
778
779 return ret;
780}
781
782static unsigned int sdio_uart_write_room(struct tty_struct *tty)
783{
784 struct sdio_uart_port *port = tty->driver_data;
785 return FIFO_SIZE - kfifo_len(&port->xmit_fifo);
786}
787
788static unsigned int sdio_uart_chars_in_buffer(struct tty_struct *tty)
789{
790 struct sdio_uart_port *port = tty->driver_data;
791 return kfifo_len(&port->xmit_fifo);
792}
793
794static void sdio_uart_send_xchar(struct tty_struct *tty, u8 ch)
795{
796 struct sdio_uart_port *port = tty->driver_data;
797
798 port->x_char = ch;
799 if (ch && !(port->ier & UART_IER_THRI)) {
800 if (sdio_uart_claim_func(port) != 0)
801 return;
802 sdio_uart_start_tx(port);
803 sdio_uart_irq(port->func);
804 sdio_uart_release_func(port);
805 }
806}
807
808static void sdio_uart_throttle(struct tty_struct *tty)
809{
810 struct sdio_uart_port *port = tty->driver_data;
811
812 if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
813 return;
814
815 if (sdio_uart_claim_func(port) != 0)
816 return;
817
818 if (I_IXOFF(tty)) {
819 port->x_char = STOP_CHAR(tty);
820 sdio_uart_start_tx(port);
821 }
822
823 if (C_CRTSCTS(tty))
824 sdio_uart_clear_mctrl(port, TIOCM_RTS);
825
826 sdio_uart_irq(port->func);
827 sdio_uart_release_func(port);
828}
829
830static void sdio_uart_unthrottle(struct tty_struct *tty)
831{
832 struct sdio_uart_port *port = tty->driver_data;
833
834 if (!I_IXOFF(tty) && !C_CRTSCTS(tty))
835 return;
836
837 if (sdio_uart_claim_func(port) != 0)
838 return;
839
840 if (I_IXOFF(tty)) {
841 if (port->x_char) {
842 port->x_char = 0;
843 } else {
844 port->x_char = START_CHAR(tty);
845 sdio_uart_start_tx(port);
846 }
847 }
848
849 if (C_CRTSCTS(tty))
850 sdio_uart_set_mctrl(port, TIOCM_RTS);
851
852 sdio_uart_irq(port->func);
853 sdio_uart_release_func(port);
854}
855
856static void sdio_uart_set_termios(struct tty_struct *tty,
857 const struct ktermios *old_termios)
858{
859 struct sdio_uart_port *port = tty->driver_data;
860 unsigned int cflag = tty->termios.c_cflag;
861
862 if (sdio_uart_claim_func(port) != 0)
863 return;
864
865 sdio_uart_change_speed(port, &tty->termios, old_termios);
866
867 /* Handle transition to B0 status */
868 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
869 sdio_uart_clear_mctrl(port, TIOCM_RTS | TIOCM_DTR);
870
871 /* Handle transition away from B0 status */
872 if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
873 unsigned int mask = TIOCM_DTR;
874 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
875 mask |= TIOCM_RTS;
876 sdio_uart_set_mctrl(port, mask);
877 }
878
879 /* Handle turning off CRTSCTS */
880 if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) {
881 tty->hw_stopped = false;
882 sdio_uart_start_tx(port);
883 }
884
885 /* Handle turning on CRTSCTS */
886 if (!(old_termios->c_cflag & CRTSCTS) && (cflag & CRTSCTS)) {
887 if (!(sdio_uart_get_mctrl(port) & TIOCM_CTS)) {
888 tty->hw_stopped = true;
889 sdio_uart_stop_tx(port);
890 }
891 }
892
893 sdio_uart_release_func(port);
894}
895
896static int sdio_uart_break_ctl(struct tty_struct *tty, int break_state)
897{
898 struct sdio_uart_port *port = tty->driver_data;
899 int result;
900
901 result = sdio_uart_claim_func(port);
902 if (result != 0)
903 return result;
904
905 if (break_state == -1)
906 port->lcr |= UART_LCR_SBC;
907 else
908 port->lcr &= ~UART_LCR_SBC;
909 sdio_out(port, UART_LCR, port->lcr);
910
911 sdio_uart_release_func(port);
912 return 0;
913}
914
915static int sdio_uart_tiocmget(struct tty_struct *tty)
916{
917 struct sdio_uart_port *port = tty->driver_data;
918 int result;
919
920 result = sdio_uart_claim_func(port);
921 if (!result) {
922 result = port->mctrl | sdio_uart_get_mctrl(port);
923 sdio_uart_release_func(port);
924 }
925
926 return result;
927}
928
929static int sdio_uart_tiocmset(struct tty_struct *tty,
930 unsigned int set, unsigned int clear)
931{
932 struct sdio_uart_port *port = tty->driver_data;
933 int result;
934
935 result = sdio_uart_claim_func(port);
936 if (!result) {
937 sdio_uart_update_mctrl(port, set, clear);
938 sdio_uart_release_func(port);
939 }
940
941 return result;
942}
943
944static int sdio_uart_proc_show(struct seq_file *m, void *v)
945{
946 int i;
947
948 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n",
949 "", "", "");
950 for (i = 0; i < UART_NR; i++) {
951 struct sdio_uart_port *port = sdio_uart_port_get(i);
952 if (port) {
953 seq_printf(m, "%d: uart:SDIO", i);
954 if (capable(CAP_SYS_ADMIN)) {
955 seq_printf(m, " tx:%d rx:%d",
956 port->icount.tx, port->icount.rx);
957 if (port->icount.frame)
958 seq_printf(m, " fe:%d",
959 port->icount.frame);
960 if (port->icount.parity)
961 seq_printf(m, " pe:%d",
962 port->icount.parity);
963 if (port->icount.brk)
964 seq_printf(m, " brk:%d",
965 port->icount.brk);
966 if (port->icount.overrun)
967 seq_printf(m, " oe:%d",
968 port->icount.overrun);
969 if (port->icount.cts)
970 seq_printf(m, " cts:%d",
971 port->icount.cts);
972 if (port->icount.dsr)
973 seq_printf(m, " dsr:%d",
974 port->icount.dsr);
975 if (port->icount.rng)
976 seq_printf(m, " rng:%d",
977 port->icount.rng);
978 if (port->icount.dcd)
979 seq_printf(m, " dcd:%d",
980 port->icount.dcd);
981 }
982 sdio_uart_port_put(port);
983 seq_putc(m, '\n');
984 }
985 }
986 return 0;
987}
988
989static const struct tty_port_operations sdio_uart_port_ops = {
990 .dtr_rts = uart_dtr_rts,
991 .carrier_raised = uart_carrier_raised,
992 .shutdown = sdio_uart_shutdown,
993 .activate = sdio_uart_activate,
994 .destruct = sdio_uart_port_destroy,
995};
996
997static const struct tty_operations sdio_uart_ops = {
998 .open = sdio_uart_open,
999 .close = sdio_uart_close,
1000 .write = sdio_uart_write,
1001 .write_room = sdio_uart_write_room,
1002 .chars_in_buffer = sdio_uart_chars_in_buffer,
1003 .send_xchar = sdio_uart_send_xchar,
1004 .throttle = sdio_uart_throttle,
1005 .unthrottle = sdio_uart_unthrottle,
1006 .set_termios = sdio_uart_set_termios,
1007 .hangup = sdio_uart_hangup,
1008 .break_ctl = sdio_uart_break_ctl,
1009 .tiocmget = sdio_uart_tiocmget,
1010 .tiocmset = sdio_uart_tiocmset,
1011 .install = sdio_uart_install,
1012 .cleanup = sdio_uart_cleanup,
1013 .proc_show = sdio_uart_proc_show,
1014};
1015
1016static struct tty_driver *sdio_uart_tty_driver;
1017
1018static int sdio_uart_probe(struct sdio_func *func,
1019 const struct sdio_device_id *id)
1020{
1021 struct sdio_uart_port *port;
1022 int ret;
1023
1024 port = kzalloc(sizeof(struct sdio_uart_port), GFP_KERNEL);
1025 if (!port)
1026 return -ENOMEM;
1027
1028 if (func->class == SDIO_CLASS_UART) {
1029 pr_warn("%s: need info on UART class basic setup\n",
1030 sdio_func_id(func));
1031 kfree(port);
1032 return -ENOSYS;
1033 } else if (func->class == SDIO_CLASS_GPS) {
1034 /*
1035 * We need tuple 0x91. It contains SUBTPL_SIOREG
1036 * and SUBTPL_RCVCAPS.
1037 */
1038 struct sdio_func_tuple *tpl;
1039 for (tpl = func->tuples; tpl; tpl = tpl->next) {
1040 if (tpl->code != 0x91)
1041 continue;
1042 if (tpl->size < 10)
1043 continue;
1044 if (tpl->data[1] == 0) /* SUBTPL_SIOREG */
1045 break;
1046 }
1047 if (!tpl) {
1048 pr_warn("%s: can't find tuple 0x91 subtuple 0 (SUBTPL_SIOREG) for GPS class\n",
1049 sdio_func_id(func));
1050 kfree(port);
1051 return -EINVAL;
1052 }
1053 pr_debug("%s: Register ID = 0x%02x, Exp ID = 0x%02x\n",
1054 sdio_func_id(func), tpl->data[2], tpl->data[3]);
1055 port->regs_offset = (tpl->data[4] << 0) |
1056 (tpl->data[5] << 8) |
1057 (tpl->data[6] << 16);
1058 pr_debug("%s: regs offset = 0x%x\n",
1059 sdio_func_id(func), port->regs_offset);
1060 port->uartclk = tpl->data[7] * 115200;
1061 if (port->uartclk == 0)
1062 port->uartclk = 115200;
1063 pr_debug("%s: clk %d baudcode %u 4800-div %u\n",
1064 sdio_func_id(func), port->uartclk,
1065 tpl->data[7], tpl->data[8] | (tpl->data[9] << 8));
1066 } else {
1067 kfree(port);
1068 return -EINVAL;
1069 }
1070
1071 port->func = func;
1072 sdio_set_drvdata(func, port);
1073 tty_port_init(&port->port);
1074 port->port.ops = &sdio_uart_port_ops;
1075
1076 ret = sdio_uart_add_port(port);
1077 if (ret) {
1078 kfree(port);
1079 } else {
1080 struct device *dev;
1081 dev = tty_port_register_device(&port->port,
1082 sdio_uart_tty_driver, port->index, &func->dev);
1083 if (IS_ERR(dev)) {
1084 sdio_uart_port_remove(port);
1085 ret = PTR_ERR(dev);
1086 }
1087 }
1088
1089 return ret;
1090}
1091
1092static void sdio_uart_remove(struct sdio_func *func)
1093{
1094 struct sdio_uart_port *port = sdio_get_drvdata(func);
1095
1096 tty_unregister_device(sdio_uart_tty_driver, port->index);
1097 sdio_uart_port_remove(port);
1098}
1099
1100static const struct sdio_device_id sdio_uart_ids[] = {
1101 { SDIO_DEVICE_CLASS(SDIO_CLASS_UART) },
1102 { SDIO_DEVICE_CLASS(SDIO_CLASS_GPS) },
1103 { /* end: all zeroes */ },
1104};
1105
1106MODULE_DEVICE_TABLE(sdio, sdio_uart_ids);
1107
1108static struct sdio_driver sdio_uart_driver = {
1109 .probe = sdio_uart_probe,
1110 .remove = sdio_uart_remove,
1111 .name = "sdio_uart",
1112 .id_table = sdio_uart_ids,
1113};
1114
1115static int __init sdio_uart_init(void)
1116{
1117 int ret;
1118 struct tty_driver *tty_drv;
1119
1120 sdio_uart_tty_driver = tty_drv = tty_alloc_driver(UART_NR,
1121 TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV);
1122 if (IS_ERR(tty_drv))
1123 return PTR_ERR(tty_drv);
1124
1125 tty_drv->driver_name = "sdio_uart";
1126 tty_drv->name = "ttySDIO";
1127 tty_drv->major = 0; /* dynamically allocated */
1128 tty_drv->minor_start = 0;
1129 tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
1130 tty_drv->subtype = SERIAL_TYPE_NORMAL;
1131 tty_drv->init_termios = tty_std_termios;
1132 tty_drv->init_termios.c_cflag = B4800 | CS8 | CREAD | HUPCL | CLOCAL;
1133 tty_drv->init_termios.c_ispeed = 4800;
1134 tty_drv->init_termios.c_ospeed = 4800;
1135 tty_set_operations(tty_drv, &sdio_uart_ops);
1136
1137 ret = tty_register_driver(tty_drv);
1138 if (ret)
1139 goto err1;
1140
1141 ret = sdio_register_driver(&sdio_uart_driver);
1142 if (ret)
1143 goto err2;
1144
1145 return 0;
1146
1147err2:
1148 tty_unregister_driver(tty_drv);
1149err1:
1150 tty_driver_kref_put(tty_drv);
1151 return ret;
1152}
1153
1154static void __exit sdio_uart_exit(void)
1155{
1156 sdio_unregister_driver(&sdio_uart_driver);
1157 tty_unregister_driver(sdio_uart_tty_driver);
1158 tty_driver_kref_put(sdio_uart_tty_driver);
1159}
1160
1161module_init(sdio_uart_init);
1162module_exit(sdio_uart_exit);
1163
1164MODULE_AUTHOR("Nicolas Pitre");
1165MODULE_DESCRIPTION("SDIO UART/GPS driver");
1166MODULE_LICENSE("GPL");
Linux 6.x block layer and io_uring tree(s)