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(&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 } 109 110 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(&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 } 125 126 static void sdio_uart_port_put(struct sdio_uart_port *port) 127 { 128 tty_port_put(&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(&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 } 161 162 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(&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 } 174 175 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(port->func); 179 } 180 181 static inline u8 sdio_in(struct sdio_uart_port *port, int offset) 182 { 183 return sdio_readb(port->func, port->regs_offset + offset, NULL); 184 } 185 186 static 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 } 190 191 static 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 } 211 212 static 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 } 230 231 static 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) 244 245 static 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 } 331 332 static 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 } 339 340 static 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 } 347 348 static 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 } 354 355 static 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 } 406 407 static 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 } 445 446 static 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 int 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 */ 495 static 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 } 524 525 static 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 */ 546 547 static 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 */ 575 576 static 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; 641 642 err2: 643 sdio_disable_func(port->func); 644 err1: 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 */ 658 659 static 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 } 690 691 static 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 */ 707 708 static 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 */ 729 730 static 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 */ 740 741 static 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 } 746 747 static 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 } 752 753 static 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 } 758 759 static 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 } 781 782 static 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 } 787 788 static 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 } 793 794 static 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 } 807 808 static 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 } 829 830 static 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 } 855 856 static 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 } 895 896 static 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 } 914 915 static 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 } 928 929 static 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 } 943 944 static 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 } 988 989 static 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 }; 996 997 static 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 1016 static struct tty_driver *sdio_uart_tty_driver; 1017 1018 static 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 1092 static 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 1100 static 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 1106 MODULE_DEVICE_TABLE(sdio, sdio_uart_ids); 1107 1108 static 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 1115 static 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 1147 err2: 1148 tty_unregister_driver(tty_drv); 1149 err1: 1150 tty_driver_kref_put(tty_drv); 1151 return ret; 1152 } 1153 1154 static 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 1161 module_init(sdio_uart_init); 1162 module_exit(sdio_uart_exit); 1163 1164 MODULE_AUTHOR("Nicolas Pitre"); 1165 MODULE_LICENSE("GPL"); 1166