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