1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * st-asc.c: ST Asynchronous serial controller (ASC) driver 4 * 5 * Copyright (C) 2003-2013 STMicroelectronics (R&D) Limited 6 */ 7 8 #include <linux/module.h> 9 #include <linux/serial.h> 10 #include <linux/console.h> 11 #include <linux/sysrq.h> 12 #include <linux/pinctrl/consumer.h> 13 #include <linux/platform_device.h> 14 #include <linux/io.h> 15 #include <linux/irq.h> 16 #include <linux/tty.h> 17 #include <linux/tty_flip.h> 18 #include <linux/delay.h> 19 #include <linux/spinlock.h> 20 #include <linux/of.h> 21 #include <linux/of_platform.h> 22 #include <linux/serial_core.h> 23 #include <linux/clk.h> 24 #include <linux/gpio/consumer.h> 25 26 #define DRIVER_NAME "st-asc" 27 #define ASC_SERIAL_NAME "ttyAS" 28 #define ASC_FIFO_SIZE 16 29 #define ASC_MAX_PORTS 8 30 31 /* Pinctrl states */ 32 #define DEFAULT 0 33 #define NO_HW_FLOWCTRL 1 34 35 struct asc_port { 36 struct uart_port port; 37 struct gpio_desc *rts; 38 struct clk *clk; 39 struct pinctrl *pinctrl; 40 struct pinctrl_state *states[2]; 41 unsigned int hw_flow_control:1; 42 unsigned int force_m1:1; 43 }; 44 45 static struct asc_port asc_ports[ASC_MAX_PORTS]; 46 static struct uart_driver asc_uart_driver; 47 48 /*---- UART Register definitions ------------------------------*/ 49 50 /* Register offsets */ 51 52 #define ASC_BAUDRATE 0x00 53 #define ASC_TXBUF 0x04 54 #define ASC_RXBUF 0x08 55 #define ASC_CTL 0x0C 56 #define ASC_INTEN 0x10 57 #define ASC_STA 0x14 58 #define ASC_GUARDTIME 0x18 59 #define ASC_TIMEOUT 0x1C 60 #define ASC_TXRESET 0x20 61 #define ASC_RXRESET 0x24 62 #define ASC_RETRIES 0x28 63 64 /* ASC_RXBUF */ 65 #define ASC_RXBUF_PE 0x100 66 #define ASC_RXBUF_FE 0x200 67 /* 68 * Some of status comes from higher bits of the character and some come from 69 * the status register. Combining both of them in to single status using dummy 70 * bits. 71 */ 72 #define ASC_RXBUF_DUMMY_RX 0x10000 73 #define ASC_RXBUF_DUMMY_BE 0x20000 74 #define ASC_RXBUF_DUMMY_OE 0x40000 75 76 /* ASC_CTL */ 77 78 #define ASC_CTL_MODE_MSK 0x0007 79 #define ASC_CTL_MODE_8BIT 0x0001 80 #define ASC_CTL_MODE_7BIT_PAR 0x0003 81 #define ASC_CTL_MODE_9BIT 0x0004 82 #define ASC_CTL_MODE_8BIT_WKUP 0x0005 83 #define ASC_CTL_MODE_8BIT_PAR 0x0007 84 #define ASC_CTL_STOP_MSK 0x0018 85 #define ASC_CTL_STOP_HALFBIT 0x0000 86 #define ASC_CTL_STOP_1BIT 0x0008 87 #define ASC_CTL_STOP_1_HALFBIT 0x0010 88 #define ASC_CTL_STOP_2BIT 0x0018 89 #define ASC_CTL_PARITYODD 0x0020 90 #define ASC_CTL_LOOPBACK 0x0040 91 #define ASC_CTL_RUN 0x0080 92 #define ASC_CTL_RXENABLE 0x0100 93 #define ASC_CTL_SCENABLE 0x0200 94 #define ASC_CTL_FIFOENABLE 0x0400 95 #define ASC_CTL_CTSENABLE 0x0800 96 #define ASC_CTL_BAUDMODE 0x1000 97 98 /* ASC_GUARDTIME */ 99 100 #define ASC_GUARDTIME_MSK 0x00FF 101 102 /* ASC_INTEN */ 103 104 #define ASC_INTEN_RBE 0x0001 105 #define ASC_INTEN_TE 0x0002 106 #define ASC_INTEN_THE 0x0004 107 #define ASC_INTEN_PE 0x0008 108 #define ASC_INTEN_FE 0x0010 109 #define ASC_INTEN_OE 0x0020 110 #define ASC_INTEN_TNE 0x0040 111 #define ASC_INTEN_TOI 0x0080 112 #define ASC_INTEN_RHF 0x0100 113 114 /* ASC_RETRIES */ 115 116 #define ASC_RETRIES_MSK 0x00FF 117 118 /* ASC_RXBUF */ 119 120 #define ASC_RXBUF_MSK 0x03FF 121 122 /* ASC_STA */ 123 124 #define ASC_STA_RBF 0x0001 125 #define ASC_STA_TE 0x0002 126 #define ASC_STA_THE 0x0004 127 #define ASC_STA_PE 0x0008 128 #define ASC_STA_FE 0x0010 129 #define ASC_STA_OE 0x0020 130 #define ASC_STA_TNE 0x0040 131 #define ASC_STA_TOI 0x0080 132 #define ASC_STA_RHF 0x0100 133 #define ASC_STA_TF 0x0200 134 #define ASC_STA_NKD 0x0400 135 136 /* ASC_TIMEOUT */ 137 138 #define ASC_TIMEOUT_MSK 0x00FF 139 140 /* ASC_TXBUF */ 141 142 #define ASC_TXBUF_MSK 0x01FF 143 144 /*---- Inline function definitions ---------------------------*/ 145 146 static inline struct asc_port *to_asc_port(struct uart_port *port) 147 { 148 return container_of(port, struct asc_port, port); 149 } 150 151 static inline u32 asc_in(struct uart_port *port, u32 offset) 152 { 153 #ifdef readl_relaxed 154 return readl_relaxed(port->membase + offset); 155 #else 156 return readl(port->membase + offset); 157 #endif 158 } 159 160 static inline void asc_out(struct uart_port *port, u32 offset, u32 value) 161 { 162 #ifdef writel_relaxed 163 writel_relaxed(value, port->membase + offset); 164 #else 165 writel(value, port->membase + offset); 166 #endif 167 } 168 169 /* 170 * Some simple utility functions to enable and disable interrupts. 171 * Note that these need to be called with interrupts disabled. 172 */ 173 static inline void asc_disable_tx_interrupts(struct uart_port *port) 174 { 175 u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_THE; 176 asc_out(port, ASC_INTEN, intenable); 177 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ 178 } 179 180 static inline void asc_enable_tx_interrupts(struct uart_port *port) 181 { 182 u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_THE; 183 asc_out(port, ASC_INTEN, intenable); 184 } 185 186 static inline void asc_disable_rx_interrupts(struct uart_port *port) 187 { 188 u32 intenable = asc_in(port, ASC_INTEN) & ~ASC_INTEN_RBE; 189 asc_out(port, ASC_INTEN, intenable); 190 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ 191 } 192 193 static inline void asc_enable_rx_interrupts(struct uart_port *port) 194 { 195 u32 intenable = asc_in(port, ASC_INTEN) | ASC_INTEN_RBE; 196 asc_out(port, ASC_INTEN, intenable); 197 } 198 199 static inline u32 asc_txfifo_is_empty(struct uart_port *port) 200 { 201 return asc_in(port, ASC_STA) & ASC_STA_TE; 202 } 203 204 static inline u32 asc_txfifo_is_half_empty(struct uart_port *port) 205 { 206 return asc_in(port, ASC_STA) & ASC_STA_THE; 207 } 208 209 static inline const char *asc_port_name(struct uart_port *port) 210 { 211 return to_platform_device(port->dev)->name; 212 } 213 214 /*----------------------------------------------------------------------*/ 215 216 /* 217 * This section contains code to support the use of the ASC as a 218 * generic serial port. 219 */ 220 221 static inline unsigned asc_hw_txroom(struct uart_port *port) 222 { 223 u32 status = asc_in(port, ASC_STA); 224 225 if (status & ASC_STA_THE) 226 return port->fifosize / 2; 227 else if (!(status & ASC_STA_TF)) 228 return 1; 229 230 return 0; 231 } 232 233 /* 234 * Start transmitting chars. 235 * This is called from both interrupt and task level. 236 * Either way interrupts are disabled. 237 */ 238 static void asc_transmit_chars(struct uart_port *port) 239 { 240 u8 ch; 241 242 uart_port_tx_limited(port, ch, asc_hw_txroom(port), 243 true, 244 asc_out(port, ASC_TXBUF, ch), 245 ({})); 246 } 247 248 static void asc_receive_chars(struct uart_port *port) 249 { 250 struct tty_port *tport = &port->state->port; 251 unsigned long status, mode; 252 unsigned long c = 0; 253 u8 flag; 254 bool ignore_pe = false; 255 256 /* 257 * Datasheet states: If the MODE field selects an 8-bit frame then 258 * this [parity error] bit is undefined. Software should ignore this 259 * bit when reading 8-bit frames. 260 */ 261 mode = asc_in(port, ASC_CTL) & ASC_CTL_MODE_MSK; 262 if (mode == ASC_CTL_MODE_8BIT || mode == ASC_CTL_MODE_8BIT_PAR) 263 ignore_pe = true; 264 265 if (irqd_is_wakeup_set(irq_get_irq_data(port->irq))) 266 pm_wakeup_event(tport->tty->dev, 0); 267 268 while ((status = asc_in(port, ASC_STA)) & ASC_STA_RBF) { 269 c = asc_in(port, ASC_RXBUF) | ASC_RXBUF_DUMMY_RX; 270 flag = TTY_NORMAL; 271 port->icount.rx++; 272 273 if (status & ASC_STA_OE || c & ASC_RXBUF_FE || 274 (c & ASC_RXBUF_PE && !ignore_pe)) { 275 276 if (c & ASC_RXBUF_FE) { 277 if (c == (ASC_RXBUF_FE | ASC_RXBUF_DUMMY_RX)) { 278 port->icount.brk++; 279 if (uart_handle_break(port)) 280 continue; 281 c |= ASC_RXBUF_DUMMY_BE; 282 } else { 283 port->icount.frame++; 284 } 285 } else if (c & ASC_RXBUF_PE) { 286 port->icount.parity++; 287 } 288 /* 289 * Reading any data from the RX FIFO clears the 290 * overflow error condition. 291 */ 292 if (status & ASC_STA_OE) { 293 port->icount.overrun++; 294 c |= ASC_RXBUF_DUMMY_OE; 295 } 296 297 c &= port->read_status_mask; 298 299 if (c & ASC_RXBUF_DUMMY_BE) 300 flag = TTY_BREAK; 301 else if (c & ASC_RXBUF_PE) 302 flag = TTY_PARITY; 303 else if (c & ASC_RXBUF_FE) 304 flag = TTY_FRAME; 305 } 306 307 if (uart_handle_sysrq_char(port, c & 0xff)) 308 continue; 309 310 uart_insert_char(port, c, ASC_RXBUF_DUMMY_OE, c & 0xff, flag); 311 } 312 313 /* Tell the rest of the system the news. New characters! */ 314 tty_flip_buffer_push(tport); 315 } 316 317 static irqreturn_t asc_interrupt(int irq, void *ptr) 318 { 319 struct uart_port *port = ptr; 320 u32 status; 321 322 spin_lock(&port->lock); 323 324 status = asc_in(port, ASC_STA); 325 326 if (status & ASC_STA_RBF) { 327 /* Receive FIFO not empty */ 328 asc_receive_chars(port); 329 } 330 331 if ((status & ASC_STA_THE) && 332 (asc_in(port, ASC_INTEN) & ASC_INTEN_THE)) { 333 /* Transmitter FIFO at least half empty */ 334 asc_transmit_chars(port); 335 } 336 337 spin_unlock(&port->lock); 338 339 return IRQ_HANDLED; 340 } 341 342 /*----------------------------------------------------------------------*/ 343 344 /* 345 * UART Functions 346 */ 347 348 static unsigned int asc_tx_empty(struct uart_port *port) 349 { 350 return asc_txfifo_is_empty(port) ? TIOCSER_TEMT : 0; 351 } 352 353 static void asc_set_mctrl(struct uart_port *port, unsigned int mctrl) 354 { 355 struct asc_port *ascport = to_asc_port(port); 356 357 /* 358 * This routine is used for seting signals of: DTR, DCD, CTS and RTS. 359 * We use ASC's hardware for CTS/RTS when hardware flow-control is 360 * enabled, however if the RTS line is required for another purpose, 361 * commonly controlled using HUP from userspace, then we need to toggle 362 * it manually, using GPIO. 363 * 364 * Some boards also have DTR and DCD implemented using PIO pins, code to 365 * do this should be hooked in here. 366 */ 367 368 if (!ascport->rts) 369 return; 370 371 /* If HW flow-control is enabled, we can't fiddle with the RTS line */ 372 if (asc_in(port, ASC_CTL) & ASC_CTL_CTSENABLE) 373 return; 374 375 gpiod_set_value(ascport->rts, mctrl & TIOCM_RTS); 376 } 377 378 static unsigned int asc_get_mctrl(struct uart_port *port) 379 { 380 /* 381 * This routine is used for geting signals of: DTR, DCD, DSR, RI, 382 * and CTS/RTS 383 */ 384 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS; 385 } 386 387 /* There are probably characters waiting to be transmitted. */ 388 static void asc_start_tx(struct uart_port *port) 389 { 390 struct circ_buf *xmit = &port->state->xmit; 391 392 if (!uart_circ_empty(xmit)) 393 asc_enable_tx_interrupts(port); 394 } 395 396 /* Transmit stop */ 397 static void asc_stop_tx(struct uart_port *port) 398 { 399 asc_disable_tx_interrupts(port); 400 } 401 402 /* Receive stop */ 403 static void asc_stop_rx(struct uart_port *port) 404 { 405 asc_disable_rx_interrupts(port); 406 } 407 408 /* Handle breaks - ignored by us */ 409 static void asc_break_ctl(struct uart_port *port, int break_state) 410 { 411 /* Nothing here yet .. */ 412 } 413 414 /* 415 * Enable port for reception. 416 */ 417 static int asc_startup(struct uart_port *port) 418 { 419 if (request_irq(port->irq, asc_interrupt, 0, 420 asc_port_name(port), port)) { 421 dev_err(port->dev, "cannot allocate irq.\n"); 422 return -ENODEV; 423 } 424 425 asc_transmit_chars(port); 426 asc_enable_rx_interrupts(port); 427 428 return 0; 429 } 430 431 static void asc_shutdown(struct uart_port *port) 432 { 433 asc_disable_tx_interrupts(port); 434 asc_disable_rx_interrupts(port); 435 free_irq(port->irq, port); 436 } 437 438 static void asc_pm(struct uart_port *port, unsigned int state, 439 unsigned int oldstate) 440 { 441 struct asc_port *ascport = to_asc_port(port); 442 unsigned long flags; 443 u32 ctl; 444 445 switch (state) { 446 case UART_PM_STATE_ON: 447 clk_prepare_enable(ascport->clk); 448 break; 449 case UART_PM_STATE_OFF: 450 /* 451 * Disable the ASC baud rate generator, which is as close as 452 * we can come to turning it off. Note this is not called with 453 * the port spinlock held. 454 */ 455 spin_lock_irqsave(&port->lock, flags); 456 ctl = asc_in(port, ASC_CTL) & ~ASC_CTL_RUN; 457 asc_out(port, ASC_CTL, ctl); 458 spin_unlock_irqrestore(&port->lock, flags); 459 clk_disable_unprepare(ascport->clk); 460 break; 461 } 462 } 463 464 static void asc_set_termios(struct uart_port *port, struct ktermios *termios, 465 const struct ktermios *old) 466 { 467 struct asc_port *ascport = to_asc_port(port); 468 struct gpio_desc *gpiod; 469 unsigned int baud; 470 u32 ctrl_val; 471 tcflag_t cflag; 472 unsigned long flags; 473 474 /* Update termios to reflect hardware capabilities */ 475 termios->c_cflag &= ~(CMSPAR | 476 (ascport->hw_flow_control ? 0 : CRTSCTS)); 477 478 port->uartclk = clk_get_rate(ascport->clk); 479 480 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16); 481 cflag = termios->c_cflag; 482 483 spin_lock_irqsave(&port->lock, flags); 484 485 /* read control register */ 486 ctrl_val = asc_in(port, ASC_CTL); 487 488 /* stop serial port and reset value */ 489 asc_out(port, ASC_CTL, (ctrl_val & ~ASC_CTL_RUN)); 490 ctrl_val = ASC_CTL_RXENABLE | ASC_CTL_FIFOENABLE; 491 492 /* reset fifo rx & tx */ 493 asc_out(port, ASC_TXRESET, 1); 494 asc_out(port, ASC_RXRESET, 1); 495 496 /* set character length */ 497 if ((cflag & CSIZE) == CS7) { 498 ctrl_val |= ASC_CTL_MODE_7BIT_PAR; 499 cflag |= PARENB; 500 } else { 501 ctrl_val |= (cflag & PARENB) ? ASC_CTL_MODE_8BIT_PAR : 502 ASC_CTL_MODE_8BIT; 503 cflag &= ~CSIZE; 504 cflag |= CS8; 505 } 506 termios->c_cflag = cflag; 507 508 /* set stop bit */ 509 ctrl_val |= (cflag & CSTOPB) ? ASC_CTL_STOP_2BIT : ASC_CTL_STOP_1BIT; 510 511 /* odd parity */ 512 if (cflag & PARODD) 513 ctrl_val |= ASC_CTL_PARITYODD; 514 515 /* hardware flow control */ 516 if ((cflag & CRTSCTS)) { 517 ctrl_val |= ASC_CTL_CTSENABLE; 518 519 /* If flow-control selected, stop handling RTS manually */ 520 if (ascport->rts) { 521 devm_gpiod_put(port->dev, ascport->rts); 522 ascport->rts = NULL; 523 524 pinctrl_select_state(ascport->pinctrl, 525 ascport->states[DEFAULT]); 526 } 527 } else { 528 /* If flow-control disabled, it's safe to handle RTS manually */ 529 if (!ascport->rts && ascport->states[NO_HW_FLOWCTRL]) { 530 pinctrl_select_state(ascport->pinctrl, 531 ascport->states[NO_HW_FLOWCTRL]); 532 533 gpiod = devm_gpiod_get(port->dev, "rts", GPIOD_OUT_LOW); 534 if (!IS_ERR(gpiod)) { 535 gpiod_set_consumer_name(gpiod, 536 port->dev->of_node->name); 537 ascport->rts = gpiod; 538 } 539 } 540 } 541 542 if ((baud < 19200) && !ascport->force_m1) { 543 asc_out(port, ASC_BAUDRATE, (port->uartclk / (16 * baud))); 544 } else { 545 /* 546 * MODE 1: recommended for high bit rates (above 19.2K) 547 * 548 * baudrate * 16 * 2^16 549 * ASCBaudRate = ------------------------ 550 * inputclock 551 * 552 * To keep maths inside 64bits, we divide inputclock by 16. 553 */ 554 u64 dividend = (u64)baud * (1 << 16); 555 556 do_div(dividend, port->uartclk / 16); 557 asc_out(port, ASC_BAUDRATE, dividend); 558 ctrl_val |= ASC_CTL_BAUDMODE; 559 } 560 561 uart_update_timeout(port, cflag, baud); 562 563 ascport->port.read_status_mask = ASC_RXBUF_DUMMY_OE; 564 if (termios->c_iflag & INPCK) 565 ascport->port.read_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE; 566 if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) 567 ascport->port.read_status_mask |= ASC_RXBUF_DUMMY_BE; 568 569 /* 570 * Characters to ignore 571 */ 572 ascport->port.ignore_status_mask = 0; 573 if (termios->c_iflag & IGNPAR) 574 ascport->port.ignore_status_mask |= ASC_RXBUF_FE | ASC_RXBUF_PE; 575 if (termios->c_iflag & IGNBRK) { 576 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_BE; 577 /* 578 * If we're ignoring parity and break indicators, 579 * ignore overruns too (for real raw support). 580 */ 581 if (termios->c_iflag & IGNPAR) 582 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_OE; 583 } 584 585 /* 586 * Ignore all characters if CREAD is not set. 587 */ 588 if (!(termios->c_cflag & CREAD)) 589 ascport->port.ignore_status_mask |= ASC_RXBUF_DUMMY_RX; 590 591 /* Set the timeout */ 592 asc_out(port, ASC_TIMEOUT, 20); 593 594 /* write final value and enable port */ 595 asc_out(port, ASC_CTL, (ctrl_val | ASC_CTL_RUN)); 596 597 spin_unlock_irqrestore(&port->lock, flags); 598 } 599 600 static const char *asc_type(struct uart_port *port) 601 { 602 return (port->type == PORT_ASC) ? DRIVER_NAME : NULL; 603 } 604 605 static void asc_release_port(struct uart_port *port) 606 { 607 } 608 609 static int asc_request_port(struct uart_port *port) 610 { 611 return 0; 612 } 613 614 /* 615 * Called when the port is opened, and UPF_BOOT_AUTOCONF flag is set 616 * Set type field if successful 617 */ 618 static void asc_config_port(struct uart_port *port, int flags) 619 { 620 if ((flags & UART_CONFIG_TYPE)) 621 port->type = PORT_ASC; 622 } 623 624 static int 625 asc_verify_port(struct uart_port *port, struct serial_struct *ser) 626 { 627 /* No user changeable parameters */ 628 return -EINVAL; 629 } 630 631 #ifdef CONFIG_CONSOLE_POLL 632 /* 633 * Console polling routines for writing and reading from the uart while 634 * in an interrupt or debug context (i.e. kgdb). 635 */ 636 637 static int asc_get_poll_char(struct uart_port *port) 638 { 639 if (!(asc_in(port, ASC_STA) & ASC_STA_RBF)) 640 return NO_POLL_CHAR; 641 642 return asc_in(port, ASC_RXBUF); 643 } 644 645 static void asc_put_poll_char(struct uart_port *port, unsigned char c) 646 { 647 while (!asc_txfifo_is_half_empty(port)) 648 cpu_relax(); 649 asc_out(port, ASC_TXBUF, c); 650 } 651 652 #endif /* CONFIG_CONSOLE_POLL */ 653 654 /*---------------------------------------------------------------------*/ 655 656 static const struct uart_ops asc_uart_ops = { 657 .tx_empty = asc_tx_empty, 658 .set_mctrl = asc_set_mctrl, 659 .get_mctrl = asc_get_mctrl, 660 .start_tx = asc_start_tx, 661 .stop_tx = asc_stop_tx, 662 .stop_rx = asc_stop_rx, 663 .break_ctl = asc_break_ctl, 664 .startup = asc_startup, 665 .shutdown = asc_shutdown, 666 .set_termios = asc_set_termios, 667 .type = asc_type, 668 .release_port = asc_release_port, 669 .request_port = asc_request_port, 670 .config_port = asc_config_port, 671 .verify_port = asc_verify_port, 672 .pm = asc_pm, 673 #ifdef CONFIG_CONSOLE_POLL 674 .poll_get_char = asc_get_poll_char, 675 .poll_put_char = asc_put_poll_char, 676 #endif /* CONFIG_CONSOLE_POLL */ 677 }; 678 679 static int asc_init_port(struct asc_port *ascport, 680 struct platform_device *pdev) 681 { 682 struct uart_port *port = &ascport->port; 683 struct resource *res; 684 int ret; 685 686 port->iotype = UPIO_MEM; 687 port->flags = UPF_BOOT_AUTOCONF; 688 port->ops = &asc_uart_ops; 689 port->fifosize = ASC_FIFO_SIZE; 690 port->dev = &pdev->dev; 691 port->irq = platform_get_irq(pdev, 0); 692 port->has_sysrq = IS_ENABLED(CONFIG_SERIAL_ST_ASC_CONSOLE); 693 694 port->membase = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 695 if (IS_ERR(port->membase)) 696 return PTR_ERR(port->membase); 697 port->mapbase = res->start; 698 699 spin_lock_init(&port->lock); 700 701 ascport->clk = devm_clk_get(&pdev->dev, NULL); 702 703 if (WARN_ON(IS_ERR(ascport->clk))) 704 return -EINVAL; 705 /* ensure that clk rate is correct by enabling the clk */ 706 ret = clk_prepare_enable(ascport->clk); 707 if (ret) 708 return ret; 709 ascport->port.uartclk = clk_get_rate(ascport->clk); 710 WARN_ON(ascport->port.uartclk == 0); 711 clk_disable_unprepare(ascport->clk); 712 713 ascport->pinctrl = devm_pinctrl_get(&pdev->dev); 714 if (IS_ERR(ascport->pinctrl)) { 715 ret = PTR_ERR(ascport->pinctrl); 716 dev_err(&pdev->dev, "Failed to get Pinctrl: %d\n", ret); 717 return ret; 718 } 719 720 ascport->states[DEFAULT] = 721 pinctrl_lookup_state(ascport->pinctrl, "default"); 722 if (IS_ERR(ascport->states[DEFAULT])) { 723 ret = PTR_ERR(ascport->states[DEFAULT]); 724 dev_err(&pdev->dev, 725 "Failed to look up Pinctrl state 'default': %d\n", ret); 726 return ret; 727 } 728 729 /* "no-hw-flowctrl" state is optional */ 730 ascport->states[NO_HW_FLOWCTRL] = 731 pinctrl_lookup_state(ascport->pinctrl, "no-hw-flowctrl"); 732 if (IS_ERR(ascport->states[NO_HW_FLOWCTRL])) 733 ascport->states[NO_HW_FLOWCTRL] = NULL; 734 735 return 0; 736 } 737 738 static struct asc_port *asc_of_get_asc_port(struct platform_device *pdev) 739 { 740 struct device_node *np = pdev->dev.of_node; 741 int id; 742 743 if (!np) 744 return NULL; 745 746 id = of_alias_get_id(np, "serial"); 747 if (id < 0) 748 id = of_alias_get_id(np, ASC_SERIAL_NAME); 749 750 if (id < 0) 751 id = 0; 752 753 if (WARN_ON(id >= ASC_MAX_PORTS)) 754 return NULL; 755 756 asc_ports[id].hw_flow_control = of_property_read_bool(np, 757 "uart-has-rtscts"); 758 asc_ports[id].force_m1 = of_property_read_bool(np, "st,force-m1"); 759 asc_ports[id].port.line = id; 760 asc_ports[id].rts = NULL; 761 762 return &asc_ports[id]; 763 } 764 765 #ifdef CONFIG_OF 766 static const struct of_device_id asc_match[] = { 767 { .compatible = "st,asc", }, 768 {}, 769 }; 770 771 MODULE_DEVICE_TABLE(of, asc_match); 772 #endif 773 774 static int asc_serial_probe(struct platform_device *pdev) 775 { 776 int ret; 777 struct asc_port *ascport; 778 779 ascport = asc_of_get_asc_port(pdev); 780 if (!ascport) 781 return -ENODEV; 782 783 ret = asc_init_port(ascport, pdev); 784 if (ret) 785 return ret; 786 787 ret = uart_add_one_port(&asc_uart_driver, &ascport->port); 788 if (ret) 789 return ret; 790 791 platform_set_drvdata(pdev, &ascport->port); 792 793 return 0; 794 } 795 796 static int asc_serial_remove(struct platform_device *pdev) 797 { 798 struct uart_port *port = platform_get_drvdata(pdev); 799 800 uart_remove_one_port(&asc_uart_driver, port); 801 802 return 0; 803 } 804 805 #ifdef CONFIG_PM_SLEEP 806 static int asc_serial_suspend(struct device *dev) 807 { 808 struct uart_port *port = dev_get_drvdata(dev); 809 810 return uart_suspend_port(&asc_uart_driver, port); 811 } 812 813 static int asc_serial_resume(struct device *dev) 814 { 815 struct uart_port *port = dev_get_drvdata(dev); 816 817 return uart_resume_port(&asc_uart_driver, port); 818 } 819 820 #endif /* CONFIG_PM_SLEEP */ 821 822 /*----------------------------------------------------------------------*/ 823 824 #ifdef CONFIG_SERIAL_ST_ASC_CONSOLE 825 static void asc_console_putchar(struct uart_port *port, unsigned char ch) 826 { 827 unsigned int timeout = 1000000; 828 829 /* Wait for upto 1 second in case flow control is stopping us. */ 830 while (--timeout && !asc_txfifo_is_half_empty(port)) 831 udelay(1); 832 833 asc_out(port, ASC_TXBUF, ch); 834 } 835 836 /* 837 * Print a string to the serial port trying not to disturb 838 * any possible real use of the port... 839 */ 840 841 static void asc_console_write(struct console *co, const char *s, unsigned count) 842 { 843 struct uart_port *port = &asc_ports[co->index].port; 844 unsigned long flags; 845 unsigned long timeout = 1000000; 846 int locked = 1; 847 u32 intenable; 848 849 if (port->sysrq) 850 locked = 0; /* asc_interrupt has already claimed the lock */ 851 else if (oops_in_progress) 852 locked = spin_trylock_irqsave(&port->lock, flags); 853 else 854 spin_lock_irqsave(&port->lock, flags); 855 856 /* 857 * Disable interrupts so we don't get the IRQ line bouncing 858 * up and down while interrupts are disabled. 859 */ 860 intenable = asc_in(port, ASC_INTEN); 861 asc_out(port, ASC_INTEN, 0); 862 (void)asc_in(port, ASC_INTEN); /* Defeat bus write posting */ 863 864 uart_console_write(port, s, count, asc_console_putchar); 865 866 while (--timeout && !asc_txfifo_is_empty(port)) 867 udelay(1); 868 869 asc_out(port, ASC_INTEN, intenable); 870 871 if (locked) 872 spin_unlock_irqrestore(&port->lock, flags); 873 } 874 875 static int asc_console_setup(struct console *co, char *options) 876 { 877 struct asc_port *ascport; 878 int baud = 115200; 879 int bits = 8; 880 int parity = 'n'; 881 int flow = 'n'; 882 883 if (co->index >= ASC_MAX_PORTS) 884 return -ENODEV; 885 886 ascport = &asc_ports[co->index]; 887 888 /* 889 * This driver does not support early console initialization 890 * (use ARM early printk support instead), so we only expect 891 * this to be called during the uart port registration when the 892 * driver gets probed and the port should be mapped at that point. 893 */ 894 if (ascport->port.mapbase == 0 || ascport->port.membase == NULL) 895 return -ENXIO; 896 897 if (options) 898 uart_parse_options(options, &baud, &parity, &bits, &flow); 899 900 return uart_set_options(&ascport->port, co, baud, parity, bits, flow); 901 } 902 903 static struct console asc_console = { 904 .name = ASC_SERIAL_NAME, 905 .device = uart_console_device, 906 .write = asc_console_write, 907 .setup = asc_console_setup, 908 .flags = CON_PRINTBUFFER, 909 .index = -1, 910 .data = &asc_uart_driver, 911 }; 912 913 #define ASC_SERIAL_CONSOLE (&asc_console) 914 915 #else 916 #define ASC_SERIAL_CONSOLE NULL 917 #endif /* CONFIG_SERIAL_ST_ASC_CONSOLE */ 918 919 static struct uart_driver asc_uart_driver = { 920 .owner = THIS_MODULE, 921 .driver_name = DRIVER_NAME, 922 .dev_name = ASC_SERIAL_NAME, 923 .major = 0, 924 .minor = 0, 925 .nr = ASC_MAX_PORTS, 926 .cons = ASC_SERIAL_CONSOLE, 927 }; 928 929 static const struct dev_pm_ops asc_serial_pm_ops = { 930 SET_SYSTEM_SLEEP_PM_OPS(asc_serial_suspend, asc_serial_resume) 931 }; 932 933 static struct platform_driver asc_serial_driver = { 934 .probe = asc_serial_probe, 935 .remove = asc_serial_remove, 936 .driver = { 937 .name = DRIVER_NAME, 938 .pm = &asc_serial_pm_ops, 939 .of_match_table = of_match_ptr(asc_match), 940 }, 941 }; 942 943 static int __init asc_init(void) 944 { 945 int ret; 946 static const char banner[] __initconst = 947 KERN_INFO "STMicroelectronics ASC driver initialized\n"; 948 949 printk(banner); 950 951 ret = uart_register_driver(&asc_uart_driver); 952 if (ret) 953 return ret; 954 955 ret = platform_driver_register(&asc_serial_driver); 956 if (ret) 957 uart_unregister_driver(&asc_uart_driver); 958 959 return ret; 960 } 961 962 static void __exit asc_exit(void) 963 { 964 platform_driver_unregister(&asc_serial_driver); 965 uart_unregister_driver(&asc_uart_driver); 966 } 967 968 module_init(asc_init); 969 module_exit(asc_exit); 970 971 MODULE_ALIAS("platform:" DRIVER_NAME); 972 MODULE_AUTHOR("STMicroelectronics (R&D) Limited"); 973 MODULE_DESCRIPTION("STMicroelectronics ASC serial port driver"); 974 MODULE_LICENSE("GPL"); 975