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 unsigned int sdio_in(struct sdio_uart_port *port, int offset) 182 { 183 unsigned char c; 184 c = sdio_readb(port->func, 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(port->func, value, 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, 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, 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, port->ier); 325 sdio_out(port, UART_LCR, cval | UART_LCR_DLAB); 326 sdio_out(port, UART_DLL, quot & 0xff); 327 sdio_out(port, UART_DLM, quot >> 8); 328 sdio_out(port, UART_LCR, cval); 329 sdio_out(port, UART_FCR, fcr); 330 331 sdio_uart_write_mctrl(port, 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, 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, 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, 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, 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, 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); 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, port->x_char); 421 port->icount.tx++; 422 port->x_char = 0; 423 return; 424 } 425 426 tty = tty_port_tty_get(&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, 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, false); 472 } 473 } 474 if (status & UART_MSR_DCTS) { 475 port->icount.cts++; 476 tty = tty_port_tty_get(&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, &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, &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(port->func); 598 if (ret) 599 goto err1; 600 ret = sdio_claim_irq(port->func, 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, 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, &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, &tty->flags); 639 640 /* Kick the IRQ handler once while we're still holding the host lock */ 641 sdio_uart_irq(port->func); 642 643 sdio_uart_release_func(port); 644 return 0; 645 646 err2: 647 sdio_disable_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(port->func); 677 port->ier = 0; 678 sdio_out(port, UART_IER, 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, 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, 0); 689 690 sdio_disable_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(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(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, 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, 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); 761 } 762 763 static int sdio_uart_write(struct tty_struct *tty, const unsigned char *buf, 764 int 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(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(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(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(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, &tty->termios, 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, 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, "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(i); 956 if (port) { 957 seq_printf(m, "%d: uart:SDIO", i); 958 if (capable(CAP_SYS_ADMIN)) { 959 seq_printf(m, " tx:%d rx:%d", 960 port->icount.tx, port->icount.rx); 961 if (port->icount.frame) 962 seq_printf(m, " fe:%d", 963 port->icount.frame); 964 if (port->icount.parity) 965 seq_printf(m, " pe:%d", 966 port->icount.parity); 967 if (port->icount.brk) 968 seq_printf(m, " brk:%d", 969 port->icount.brk); 970 if (port->icount.overrun) 971 seq_printf(m, " oe:%d", 972 port->icount.overrun); 973 if (port->icount.cts) 974 seq_printf(m, " cts:%d", 975 port->icount.cts); 976 if (port->icount.dsr) 977 seq_printf(m, " dsr:%d", 978 port->icount.dsr); 979 if (port->icount.rng) 980 seq_printf(m, " rng:%d", 981 port->icount.rng); 982 if (port->icount.dcd) 983 seq_printf(m, " dcd:%d", 984 port->icount.dcd); 985 } 986 sdio_uart_port_put(port); 987 seq_putc(m, '\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(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(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(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(port); 1072 return -EINVAL; 1073 } 1074 1075 port->func = func; 1076 sdio_set_drvdata(func, port); 1077 tty_port_init(&port->port); 1078 port->port.ops = &sdio_uart_port_ops; 1079 1080 ret = sdio_uart_add_port(port); 1081 if (ret) { 1082 kfree(port); 1083 } else { 1084 struct device *dev; 1085 dev = tty_port_register_device(&port->port, 1086 sdio_uart_tty_driver, port->index, &func->dev); 1087 if (IS_ERR(dev)) { 1088 sdio_uart_port_remove(port); 1089 ret = PTR_ERR(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(sdio_uart_tty_driver, 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(tty_drv)) 1127 return PTR_ERR(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(tty_drv, &sdio_uart_ops); 1140 1141 ret = tty_register_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(tty_drv); 1153 err1: 1154 tty_driver_kref_put(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(sdio_uart_tty_driver); 1162 tty_driver_kref_put(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