1/* 2 * Atheros AR933X SoC built-in UART driver 3 * 4 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org> 5 * 6 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o. 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License version 2 as published 10 * by the Free Software Foundation. 11 */ 12 13#include <linux/module.h> 14#include <linux/ioport.h> 15#include <linux/init.h> 16#include <linux/console.h> 17#include <linux/sysrq.h> 18#include <linux/delay.h> 19#include <linux/platform_device.h> 20#include <linux/tty.h> 21#include <linux/tty_flip.h> 22#include <linux/serial_core.h> 23#include <linux/serial.h> 24#include <linux/slab.h> 25#include <linux/io.h> 26#include <linux/irq.h> 27 28#include <asm/mach-ath79/ar933x_uart.h> 29#include <asm/mach-ath79/ar933x_uart_platform.h> 30 31#define DRIVER_NAME "ar933x-uart" 32 33#define AR933X_DUMMY_STATUS_RD 0x01 34 35static struct uart_driver ar933x_uart_driver; 36 37struct ar933x_uart_port { 38 struct uart_port port; 39 unsigned int ier; /* shadow Interrupt Enable Register */ 40}; 41 42static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up, 43 int offset) 44{ 45 return readl(up->port.membase + offset); 46} 47 48static inline void ar933x_uart_write(struct ar933x_uart_port *up, 49 int offset, unsigned int value) 50{ 51 writel(value, up->port.membase + offset); 52} 53 54static inline void ar933x_uart_rmw(struct ar933x_uart_port *up, 55 unsigned int offset, 56 unsigned int mask, 57 unsigned int val) 58{ 59 unsigned int t; 60 61 t = ar933x_uart_read(up, offset); 62 t &= ~mask; 63 t |= val; 64 ar933x_uart_write(up, offset, t); 65} 66 67static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up, 68 unsigned int offset, 69 unsigned int val) 70{ 71 ar933x_uart_rmw(up, offset, 0, val); 72} 73 74static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up, 75 unsigned int offset, 76 unsigned int val) 77{ 78 ar933x_uart_rmw(up, offset, val, 0); 79} 80 81static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up) 82{ 83 up->ier |= AR933X_UART_INT_TX_EMPTY; 84 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 85} 86 87static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up) 88{ 89 up->ier &= ~AR933X_UART_INT_TX_EMPTY; 90 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 91} 92 93static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch) 94{ 95 unsigned int rdata; 96 97 rdata = ch & AR933X_UART_DATA_TX_RX_MASK; 98 rdata |= AR933X_UART_DATA_TX_CSR; 99 ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata); 100} 101 102static unsigned int ar933x_uart_tx_empty(struct uart_port *port) 103{ 104 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 105 unsigned long flags; 106 unsigned int rdata; 107 108 spin_lock_irqsave(&up->port.lock, flags); 109 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 110 spin_unlock_irqrestore(&up->port.lock, flags); 111 112 return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT; 113} 114 115static unsigned int ar933x_uart_get_mctrl(struct uart_port *port) 116{ 117 return TIOCM_CAR; 118} 119 120static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl) 121{ 122} 123 124static void ar933x_uart_start_tx(struct uart_port *port) 125{ 126 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 127 128 ar933x_uart_start_tx_interrupt(up); 129} 130 131static void ar933x_uart_stop_tx(struct uart_port *port) 132{ 133 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 134 135 ar933x_uart_stop_tx_interrupt(up); 136} 137 138static void ar933x_uart_stop_rx(struct uart_port *port) 139{ 140 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 141 142 up->ier &= ~AR933X_UART_INT_RX_VALID; 143 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 144} 145 146static void ar933x_uart_break_ctl(struct uart_port *port, int break_state) 147{ 148 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 149 unsigned long flags; 150 151 spin_lock_irqsave(&up->port.lock, flags); 152 if (break_state == -1) 153 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 154 AR933X_UART_CS_TX_BREAK); 155 else 156 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, 157 AR933X_UART_CS_TX_BREAK); 158 spin_unlock_irqrestore(&up->port.lock, flags); 159} 160 161static void ar933x_uart_enable_ms(struct uart_port *port) 162{ 163} 164 165static void ar933x_uart_set_termios(struct uart_port *port, 166 struct ktermios *new, 167 struct ktermios *old) 168{ 169 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 170 unsigned int cs; 171 unsigned long flags; 172 unsigned int baud, scale; 173 174 /* Only CS8 is supported */ 175 new->c_cflag &= ~CSIZE; 176 new->c_cflag |= CS8; 177 178 /* Only one stop bit is supported */ 179 new->c_cflag &= ~CSTOPB; 180 181 cs = 0; 182 if (new->c_cflag & PARENB) { 183 if (!(new->c_cflag & PARODD)) 184 cs |= AR933X_UART_CS_PARITY_EVEN; 185 else 186 cs |= AR933X_UART_CS_PARITY_ODD; 187 } else { 188 cs |= AR933X_UART_CS_PARITY_NONE; 189 } 190 191 /* Mark/space parity is not supported */ 192 new->c_cflag &= ~CMSPAR; 193 194 baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16); 195 scale = (port->uartclk / (16 * baud)) - 1; 196 197 /* 198 * Ok, we're now changing the port state. Do it with 199 * interrupts disabled. 200 */ 201 spin_lock_irqsave(&up->port.lock, flags); 202 203 /* Update the per-port timeout. */ 204 uart_update_timeout(port, new->c_cflag, baud); 205 206 up->port.ignore_status_mask = 0; 207 208 /* ignore all characters if CREAD is not set */ 209 if ((new->c_cflag & CREAD) == 0) 210 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD; 211 212 ar933x_uart_write(up, AR933X_UART_CLOCK_REG, 213 scale << AR933X_UART_CLOCK_SCALE_S | 8192); 214 215 /* setup configuration register */ 216 ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs); 217 218 /* enable host interrupt */ 219 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 220 AR933X_UART_CS_HOST_INT_EN); 221 222 spin_unlock_irqrestore(&up->port.lock, flags); 223 224 if (tty_termios_baud_rate(new)) 225 tty_termios_encode_baud_rate(new, baud, baud); 226} 227 228static void ar933x_uart_rx_chars(struct ar933x_uart_port *up) 229{ 230 struct tty_struct *tty; 231 int max_count = 256; 232 233 tty = tty_port_tty_get(&up->port.state->port); 234 do { 235 unsigned int rdata; 236 unsigned char ch; 237 238 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 239 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0) 240 break; 241 242 /* remove the character from the FIFO */ 243 ar933x_uart_write(up, AR933X_UART_DATA_REG, 244 AR933X_UART_DATA_RX_CSR); 245 246 if (!tty) { 247 /* discard the data if no tty available */ 248 continue; 249 } 250 251 up->port.icount.rx++; 252 ch = rdata & AR933X_UART_DATA_TX_RX_MASK; 253 254 if (uart_handle_sysrq_char(&up->port, ch)) 255 continue; 256 257 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0) 258 tty_insert_flip_char(tty, ch, TTY_NORMAL); 259 } while (max_count-- > 0); 260 261 if (tty) { 262 tty_flip_buffer_push(tty); 263 tty_kref_put(tty); 264 } 265} 266 267static void ar933x_uart_tx_chars(struct ar933x_uart_port *up) 268{ 269 struct circ_buf *xmit = &up->port.state->xmit; 270 int count; 271 272 if (uart_tx_stopped(&up->port)) 273 return; 274 275 count = up->port.fifosize; 276 do { 277 unsigned int rdata; 278 279 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG); 280 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0) 281 break; 282 283 if (up->port.x_char) { 284 ar933x_uart_putc(up, up->port.x_char); 285 up->port.icount.tx++; 286 up->port.x_char = 0; 287 continue; 288 } 289 290 if (uart_circ_empty(xmit)) 291 break; 292 293 ar933x_uart_putc(up, xmit->buf[xmit->tail]); 294 295 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); 296 up->port.icount.tx++; 297 } while (--count > 0); 298 299 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) 300 uart_write_wakeup(&up->port); 301 302 if (!uart_circ_empty(xmit)) 303 ar933x_uart_start_tx_interrupt(up); 304} 305 306static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id) 307{ 308 struct ar933x_uart_port *up = dev_id; 309 unsigned int status; 310 311 status = ar933x_uart_read(up, AR933X_UART_CS_REG); 312 if ((status & AR933X_UART_CS_HOST_INT) == 0) 313 return IRQ_NONE; 314 315 spin_lock(&up->port.lock); 316 317 status = ar933x_uart_read(up, AR933X_UART_INT_REG); 318 status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG); 319 320 if (status & AR933X_UART_INT_RX_VALID) { 321 ar933x_uart_write(up, AR933X_UART_INT_REG, 322 AR933X_UART_INT_RX_VALID); 323 ar933x_uart_rx_chars(up); 324 } 325 326 if (status & AR933X_UART_INT_TX_EMPTY) { 327 ar933x_uart_write(up, AR933X_UART_INT_REG, 328 AR933X_UART_INT_TX_EMPTY); 329 ar933x_uart_stop_tx_interrupt(up); 330 ar933x_uart_tx_chars(up); 331 } 332 333 spin_unlock(&up->port.lock); 334 335 return IRQ_HANDLED; 336} 337 338static int ar933x_uart_startup(struct uart_port *port) 339{ 340 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 341 unsigned long flags; 342 int ret; 343 344 ret = request_irq(up->port.irq, ar933x_uart_interrupt, 345 up->port.irqflags, dev_name(up->port.dev), up); 346 if (ret) 347 return ret; 348 349 spin_lock_irqsave(&up->port.lock, flags); 350 351 /* Enable HOST interrupts */ 352 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG, 353 AR933X_UART_CS_HOST_INT_EN); 354 355 /* Enable RX interrupts */ 356 up->ier = AR933X_UART_INT_RX_VALID; 357 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 358 359 spin_unlock_irqrestore(&up->port.lock, flags); 360 361 return 0; 362} 363 364static void ar933x_uart_shutdown(struct uart_port *port) 365{ 366 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 367 368 /* Disable all interrupts */ 369 up->ier = 0; 370 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier); 371 372 /* Disable break condition */ 373 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG, 374 AR933X_UART_CS_TX_BREAK); 375 376 free_irq(up->port.irq, up); 377} 378 379static const char *ar933x_uart_type(struct uart_port *port) 380{ 381 return (port->type == PORT_AR933X) ? "AR933X UART" : NULL; 382} 383 384static void ar933x_uart_release_port(struct uart_port *port) 385{ 386 /* Nothing to release ... */ 387} 388 389static int ar933x_uart_request_port(struct uart_port *port) 390{ 391 /* UARTs always present */ 392 return 0; 393} 394 395static void ar933x_uart_config_port(struct uart_port *port, int flags) 396{ 397 if (flags & UART_CONFIG_TYPE) 398 port->type = PORT_AR933X; 399} 400 401static int ar933x_uart_verify_port(struct uart_port *port, 402 struct serial_struct *ser) 403{ 404 if (ser->type != PORT_UNKNOWN && 405 ser->type != PORT_AR933X) 406 return -EINVAL; 407 408 if (ser->irq < 0 || ser->irq >= NR_IRQS) 409 return -EINVAL; 410 411 if (ser->baud_base < 28800) 412 return -EINVAL; 413 414 return 0; 415} 416 417static struct uart_ops ar933x_uart_ops = { 418 .tx_empty = ar933x_uart_tx_empty, 419 .set_mctrl = ar933x_uart_set_mctrl, 420 .get_mctrl = ar933x_uart_get_mctrl, 421 .stop_tx = ar933x_uart_stop_tx, 422 .start_tx = ar933x_uart_start_tx, 423 .stop_rx = ar933x_uart_stop_rx, 424 .enable_ms = ar933x_uart_enable_ms, 425 .break_ctl = ar933x_uart_break_ctl, 426 .startup = ar933x_uart_startup, 427 .shutdown = ar933x_uart_shutdown, 428 .set_termios = ar933x_uart_set_termios, 429 .type = ar933x_uart_type, 430 .release_port = ar933x_uart_release_port, 431 .request_port = ar933x_uart_request_port, 432 .config_port = ar933x_uart_config_port, 433 .verify_port = ar933x_uart_verify_port, 434}; 435 436#ifdef CONFIG_SERIAL_AR933X_CONSOLE 437 438static struct ar933x_uart_port * 439ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS]; 440 441static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up) 442{ 443 unsigned int status; 444 unsigned int timeout = 60000; 445 446 /* Wait up to 60ms for the character(s) to be sent. */ 447 do { 448 status = ar933x_uart_read(up, AR933X_UART_DATA_REG); 449 if (--timeout == 0) 450 break; 451 udelay(1); 452 } while ((status & AR933X_UART_DATA_TX_CSR) == 0); 453} 454 455static void ar933x_uart_console_putchar(struct uart_port *port, int ch) 456{ 457 struct ar933x_uart_port *up = (struct ar933x_uart_port *) port; 458 459 ar933x_uart_wait_xmitr(up); 460 ar933x_uart_putc(up, ch); 461} 462 463static void ar933x_uart_console_write(struct console *co, const char *s, 464 unsigned int count) 465{ 466 struct ar933x_uart_port *up = ar933x_console_ports[co->index]; 467 unsigned long flags; 468 unsigned int int_en; 469 int locked = 1; 470 471 local_irq_save(flags); 472 473 if (up->port.sysrq) 474 locked = 0; 475 else if (oops_in_progress) 476 locked = spin_trylock(&up->port.lock); 477 else 478 spin_lock(&up->port.lock); 479 480 /* 481 * First save the IER then disable the interrupts 482 */ 483 int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG); 484 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0); 485 486 uart_console_write(&up->port, s, count, ar933x_uart_console_putchar); 487 488 /* 489 * Finally, wait for transmitter to become empty 490 * and restore the IER 491 */ 492 ar933x_uart_wait_xmitr(up); 493 ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en); 494 495 ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS); 496 497 if (locked) 498 spin_unlock(&up->port.lock); 499 500 local_irq_restore(flags); 501} 502 503static int ar933x_uart_console_setup(struct console *co, char *options) 504{ 505 struct ar933x_uart_port *up; 506 int baud = 115200; 507 int bits = 8; 508 int parity = 'n'; 509 int flow = 'n'; 510 511 if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS) 512 return -EINVAL; 513 514 up = ar933x_console_ports[co->index]; 515 if (!up) 516 return -ENODEV; 517 518 if (options) 519 uart_parse_options(options, &baud, &parity, &bits, &flow); 520 521 return uart_set_options(&up->port, co, baud, parity, bits, flow); 522} 523 524static struct console ar933x_uart_console = { 525 .name = "ttyATH", 526 .write = ar933x_uart_console_write, 527 .device = uart_console_device, 528 .setup = ar933x_uart_console_setup, 529 .flags = CON_PRINTBUFFER, 530 .index = -1, 531 .data = &ar933x_uart_driver, 532}; 533 534static void ar933x_uart_add_console_port(struct ar933x_uart_port *up) 535{ 536 ar933x_console_ports[up->port.line] = up; 537} 538 539#define AR933X_SERIAL_CONSOLE (&ar933x_uart_console) 540 541#else 542 543static inline void ar933x_uart_add_console_port(struct ar933x_uart_port *up) {} 544 545#define AR933X_SERIAL_CONSOLE NULL 546 547#endif /* CONFIG_SERIAL_AR933X_CONSOLE */ 548 549static struct uart_driver ar933x_uart_driver = { 550 .owner = THIS_MODULE, 551 .driver_name = DRIVER_NAME, 552 .dev_name = "ttyATH", 553 .nr = CONFIG_SERIAL_AR933X_NR_UARTS, 554 .cons = AR933X_SERIAL_CONSOLE, 555}; 556 557static int __devinit ar933x_uart_probe(struct platform_device *pdev) 558{ 559 struct ar933x_uart_platform_data *pdata; 560 struct ar933x_uart_port *up; 561 struct uart_port *port; 562 struct resource *mem_res; 563 struct resource *irq_res; 564 int id; 565 int ret; 566 567 pdata = pdev->dev.platform_data; 568 if (!pdata) 569 return -EINVAL; 570 571 id = pdev->id; 572 if (id == -1) 573 id = 0; 574 575 if (id > CONFIG_SERIAL_AR933X_NR_UARTS) 576 return -EINVAL; 577 578 mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 579 if (!mem_res) { 580 dev_err(&pdev->dev, "no MEM resource\n"); 581 return -EINVAL; 582 } 583 584 irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 585 if (!irq_res) { 586 dev_err(&pdev->dev, "no IRQ resource\n"); 587 return -EINVAL; 588 } 589 590 up = kzalloc(sizeof(struct ar933x_uart_port), GFP_KERNEL); 591 if (!up) 592 return -ENOMEM; 593 594 port = &up->port; 595 port->mapbase = mem_res->start; 596 597 port->membase = ioremap(mem_res->start, AR933X_UART_REGS_SIZE); 598 if (!port->membase) { 599 ret = -ENOMEM; 600 goto err_free_up; 601 } 602 603 port->line = id; 604 port->irq = irq_res->start; 605 port->dev = &pdev->dev; 606 port->type = PORT_AR933X; 607 port->iotype = UPIO_MEM32; 608 port->uartclk = pdata->uartclk; 609 610 port->regshift = 2; 611 port->fifosize = AR933X_UART_FIFO_SIZE; 612 port->ops = &ar933x_uart_ops; 613 614 ar933x_uart_add_console_port(up); 615 616 ret = uart_add_one_port(&ar933x_uart_driver, &up->port); 617 if (ret) 618 goto err_unmap; 619 620 platform_set_drvdata(pdev, up); 621 return 0; 622 623err_unmap: 624 iounmap(up->port.membase); 625err_free_up: 626 kfree(up); 627 return ret; 628} 629 630static int __devexit ar933x_uart_remove(struct platform_device *pdev) 631{ 632 struct ar933x_uart_port *up; 633 634 up = platform_get_drvdata(pdev); 635 platform_set_drvdata(pdev, NULL); 636 637 if (up) { 638 uart_remove_one_port(&ar933x_uart_driver, &up->port); 639 iounmap(up->port.membase); 640 kfree(up); 641 } 642 643 return 0; 644} 645 646static struct platform_driver ar933x_uart_platform_driver = { 647 .probe = ar933x_uart_probe, 648 .remove = __devexit_p(ar933x_uart_remove), 649 .driver = { 650 .name = DRIVER_NAME, 651 .owner = THIS_MODULE, 652 }, 653}; 654 655static int __init ar933x_uart_init(void) 656{ 657 int ret; 658 659 ar933x_uart_driver.nr = CONFIG_SERIAL_AR933X_NR_UARTS; 660 ret = uart_register_driver(&ar933x_uart_driver); 661 if (ret) 662 goto err_out; 663 664 ret = platform_driver_register(&ar933x_uart_platform_driver); 665 if (ret) 666 goto err_unregister_uart_driver; 667 668 return 0; 669 670err_unregister_uart_driver: 671 uart_unregister_driver(&ar933x_uart_driver); 672err_out: 673 return ret; 674} 675 676static void __exit ar933x_uart_exit(void) 677{ 678 platform_driver_unregister(&ar933x_uart_platform_driver); 679 uart_unregister_driver(&ar933x_uart_driver); 680} 681 682module_init(ar933x_uart_init); 683module_exit(ar933x_uart_exit); 684 685MODULE_DESCRIPTION("Atheros AR933X UART driver"); 686MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>"); 687MODULE_LICENSE("GPL v2"); 688MODULE_ALIAS("platform:" DRIVER_NAME); 689