drivers/tty/serial/ar933x_uart.c

   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/div64.h>
  29
  30 #include <asm/mach-ath79/ar933x_uart.h>
  31 #include <asm/mach-ath79/ar933x_uart_platform.h>
  32
  33 #define DRIVER_NAME "ar933x-uart"
  34
  35 #define AR933X_UART_MAX_SCALE   0xff
  36 #define AR933X_UART_MAX_STEP    0xffff
  37
  38 #define AR933X_UART_MIN_BAUD    300
  39 #define AR933X_UART_MAX_BAUD    3000000
  40
  41 #define AR933X_DUMMY_STATUS_RD  0x01
  42
  43 static struct uart_driver ar933x_uart_driver;
  44
  45 struct ar933x_uart_port {
  46         struct uart_port        port;
  47         unsigned int            ier;    /* shadow Interrupt Enable Register */
  48         unsigned int            min_baud;
  49         unsigned int            max_baud;
  50 };
  51
  52 static inline unsigned int ar933x_uart_read(struct ar933x_uart_port *up,
  53                                             int offset)
  54 {
  55         return readl(up->port.membase + offset);
  56 }
  57
  58 static inline void ar933x_uart_write(struct ar933x_uart_port *up,
  59                                      int offset, unsigned int value)
  60 {
  61         writel(value, up->port.membase + offset);
  62 }
  63
  64 static inline void ar933x_uart_rmw(struct ar933x_uart_port *up,
  65                                   unsigned int offset,
  66                                   unsigned int mask,
  67                                   unsigned int val)
  68 {
  69         unsigned int t;
  70
  71         t = ar933x_uart_read(up, offset);
  72         t &= ~mask;
  73         t |= val;
  74         ar933x_uart_write(up, offset, t);
  75 }
  76
  77 static inline void ar933x_uart_rmw_set(struct ar933x_uart_port *up,
  78                                        unsigned int offset,
  79                                        unsigned int val)
  80 {
  81         ar933x_uart_rmw(up, offset, 0, val);
  82 }
  83
  84 static inline void ar933x_uart_rmw_clear(struct ar933x_uart_port *up,
  85                                          unsigned int offset,
  86                                          unsigned int val)
  87 {
  88         ar933x_uart_rmw(up, offset, val, 0);
  89 }
  90
  91 static inline void ar933x_uart_start_tx_interrupt(struct ar933x_uart_port *up)
  92 {
  93         up->ier |= AR933X_UART_INT_TX_EMPTY;
  94         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
  95 }
  96
  97 static inline void ar933x_uart_stop_tx_interrupt(struct ar933x_uart_port *up)
  98 {
  99         up->ier &= ~AR933X_UART_INT_TX_EMPTY;
 100         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 101 }
 102
 103 static inline void ar933x_uart_putc(struct ar933x_uart_port *up, int ch)
 104 {
 105         unsigned int rdata;
 106
 107         rdata = ch & AR933X_UART_DATA_TX_RX_MASK;
 108         rdata |= AR933X_UART_DATA_TX_CSR;
 109         ar933x_uart_write(up, AR933X_UART_DATA_REG, rdata);
 110 }
 111
 112 static unsigned int ar933x_uart_tx_empty(struct uart_port *port)
 113 {
 114         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 115         unsigned long flags;
 116         unsigned int rdata;
 117
 118         spin_lock_irqsave(&up->port.lock, flags);
 119         rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 120         spin_unlock_irqrestore(&up->port.lock, flags);
 121
 122         return (rdata & AR933X_UART_DATA_TX_CSR) ? 0 : TIOCSER_TEMT;
 123 }
 124
 125 static unsigned int ar933x_uart_get_mctrl(struct uart_port *port)
 126 {
 127         return TIOCM_CAR;
 128 }
 129
 130 static void ar933x_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 131 {
 132 }
 133
 134 static void ar933x_uart_start_tx(struct uart_port *port)
 135 {
 136         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 137
 138         ar933x_uart_start_tx_interrupt(up);
 139 }
 140
 141 static void ar933x_uart_stop_tx(struct uart_port *port)
 142 {
 143         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 144
 145         ar933x_uart_stop_tx_interrupt(up);
 146 }
 147
 148 static void ar933x_uart_stop_rx(struct uart_port *port)
 149 {
 150         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 151
 152         up->ier &= ~AR933X_UART_INT_RX_VALID;
 153         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 154 }
 155
 156 static void ar933x_uart_break_ctl(struct uart_port *port, int break_state)
 157 {
 158         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 159         unsigned long flags;
 160
 161         spin_lock_irqsave(&up->port.lock, flags);
 162         if (break_state == -1)
 163                 ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 164                                     AR933X_UART_CS_TX_BREAK);
 165         else
 166                 ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 167                                       AR933X_UART_CS_TX_BREAK);
 168         spin_unlock_irqrestore(&up->port.lock, flags);
 169 }
 170
 171 static void ar933x_uart_enable_ms(struct uart_port *port)
 172 {
 173 }
 174
 175 /*
 176  * baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
 177  */
 178 static unsigned long ar933x_uart_get_baud(unsigned int clk,
 179                                           unsigned int scale,
 180                                           unsigned int step)
 181 {
 182         u64 t;
 183         u32 div;
 184
 185         div = (2 << 16) * (scale + 1);
 186         t = clk;
 187         t *= step;
 188         t += (div / 2);
 189         do_div(t, div);
 190
 191         return t;
 192 }
 193
 194 static void ar933x_uart_get_scale_step(unsigned int clk,
 195                                        unsigned int baud,
 196                                        unsigned int *scale,
 197                                        unsigned int *step)
 198 {
 199         unsigned int tscale;
 200         long min_diff;
 201
 202         *scale = 0;
 203         *step = 0;
 204
 205         min_diff = baud;
 206         for (tscale = 0; tscale < AR933X_UART_MAX_SCALE; tscale++) {
 207                 u64 tstep;
 208                 int diff;
 209
 210                 tstep = baud * (tscale + 1);
 211                 tstep *= (2 << 16);
 212                 do_div(tstep, clk);
 213
 214                 if (tstep > AR933X_UART_MAX_STEP)
 215                         break;
 216
 217                 diff = abs(ar933x_uart_get_baud(clk, tscale, tstep) - baud);
 218                 if (diff < min_diff) {
 219                         min_diff = diff;
 220                         *scale = tscale;
 221                         *step = tstep;
 222                 }
 223         }
 224 }
 225
 226 static void ar933x_uart_set_termios(struct uart_port *port,
 227                                     struct ktermios *new,
 228                                     struct ktermios *old)
 229 {
 230         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 231         unsigned int cs;
 232         unsigned long flags;
 233         unsigned int baud, scale, step;
 234
 235         /* Only CS8 is supported */
 236         new->c_cflag &= ~CSIZE;
 237         new->c_cflag |= CS8;
 238
 239         /* Only one stop bit is supported */
 240         new->c_cflag &= ~CSTOPB;
 241
 242         cs = 0;
 243         if (new->c_cflag & PARENB) {
 244                 if (!(new->c_cflag & PARODD))
 245                         cs |= AR933X_UART_CS_PARITY_EVEN;
 246                 else
 247                         cs |= AR933X_UART_CS_PARITY_ODD;
 248         } else {
 249                 cs |= AR933X_UART_CS_PARITY_NONE;
 250         }
 251
 252         /* Mark/space parity is not supported */
 253         new->c_cflag &= ~CMSPAR;
 254
 255         baud = uart_get_baud_rate(port, new, old, up->min_baud, up->max_baud);
 256         ar933x_uart_get_scale_step(port->uartclk, baud, &scale, &step);
 257
 258         /*
 259          * Ok, we're now changing the port state. Do it with
 260          * interrupts disabled.
 261          */
 262         spin_lock_irqsave(&up->port.lock, flags);
 263
 264         /* disable the UART */
 265         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 266                       AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S);
 267
 268         /* Update the per-port timeout. */
 269         uart_update_timeout(port, new->c_cflag, baud);
 270
 271         up->port.ignore_status_mask = 0;
 272
 273         /* ignore all characters if CREAD is not set */
 274         if ((new->c_cflag & CREAD) == 0)
 275                 up->port.ignore_status_mask |= AR933X_DUMMY_STATUS_RD;
 276
 277         ar933x_uart_write(up, AR933X_UART_CLOCK_REG,
 278                           scale << AR933X_UART_CLOCK_SCALE_S | step);
 279
 280         /* setup configuration register */
 281         ar933x_uart_rmw(up, AR933X_UART_CS_REG, AR933X_UART_CS_PARITY_M, cs);
 282
 283         /* enable host interrupt */
 284         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 285                             AR933X_UART_CS_HOST_INT_EN);
 286
 287         /* reenable the UART */
 288         ar933x_uart_rmw(up, AR933X_UART_CS_REG,
 289                         AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
 290                         AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S);
 291
 292         spin_unlock_irqrestore(&up->port.lock, flags);
 293
 294         if (tty_termios_baud_rate(new))
 295                 tty_termios_encode_baud_rate(new, baud, baud);
 296 }
 297
 298 static void ar933x_uart_rx_chars(struct ar933x_uart_port *up)
 299 {
 300         struct tty_struct *tty;
 301         int max_count = 256;
 302
 303         tty = tty_port_tty_get(&up->port.state->port);
 304         do {
 305                 unsigned int rdata;
 306                 unsigned char ch;
 307
 308                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 309                 if ((rdata & AR933X_UART_DATA_RX_CSR) == 0)
 310                         break;
 311
 312                 /* remove the character from the FIFO */
 313                 ar933x_uart_write(up, AR933X_UART_DATA_REG,
 314                                   AR933X_UART_DATA_RX_CSR);
 315
 316                 if (!tty) {
 317                         /* discard the data if no tty available */
 318                         continue;
 319                 }
 320
 321                 up->port.icount.rx++;
 322                 ch = rdata & AR933X_UART_DATA_TX_RX_MASK;
 323
 324                 if (uart_handle_sysrq_char(&up->port, ch))
 325                         continue;
 326
 327                 if ((up->port.ignore_status_mask & AR933X_DUMMY_STATUS_RD) == 0)
 328                         tty_insert_flip_char(tty, ch, TTY_NORMAL);
 329         } while (max_count-- > 0);
 330
 331         if (tty) {
 332                 tty_flip_buffer_push(tty);
 333                 tty_kref_put(tty);
 334         }
 335 }
 336
 337 static void ar933x_uart_tx_chars(struct ar933x_uart_port *up)
 338 {
 339         struct circ_buf *xmit = &up->port.state->xmit;
 340         int count;
 341
 342         if (uart_tx_stopped(&up->port))
 343                 return;
 344
 345         count = up->port.fifosize;
 346         do {
 347                 unsigned int rdata;
 348
 349                 rdata = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 350                 if ((rdata & AR933X_UART_DATA_TX_CSR) == 0)
 351                         break;
 352
 353                 if (up->port.x_char) {
 354                         ar933x_uart_putc(up, up->port.x_char);
 355                         up->port.icount.tx++;
 356                         up->port.x_char = 0;
 357                         continue;
 358                 }
 359
 360                 if (uart_circ_empty(xmit))
 361                         break;
 362
 363                 ar933x_uart_putc(up, xmit->buf[xmit->tail]);
 364
 365                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 366                 up->port.icount.tx++;
 367         } while (--count > 0);
 368
 369         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 370                 uart_write_wakeup(&up->port);
 371
 372         if (!uart_circ_empty(xmit))
 373                 ar933x_uart_start_tx_interrupt(up);
 374 }
 375
 376 static irqreturn_t ar933x_uart_interrupt(int irq, void *dev_id)
 377 {
 378         struct ar933x_uart_port *up = dev_id;
 379         unsigned int status;
 380
 381         status = ar933x_uart_read(up, AR933X_UART_CS_REG);
 382         if ((status & AR933X_UART_CS_HOST_INT) == 0)
 383                 return IRQ_NONE;
 384
 385         spin_lock(&up->port.lock);
 386
 387         status = ar933x_uart_read(up, AR933X_UART_INT_REG);
 388         status &= ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 389
 390         if (status & AR933X_UART_INT_RX_VALID) {
 391                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 392                                   AR933X_UART_INT_RX_VALID);
 393                 ar933x_uart_rx_chars(up);
 394         }
 395
 396         if (status & AR933X_UART_INT_TX_EMPTY) {
 397                 ar933x_uart_write(up, AR933X_UART_INT_REG,
 398                                   AR933X_UART_INT_TX_EMPTY);
 399                 ar933x_uart_stop_tx_interrupt(up);
 400                 ar933x_uart_tx_chars(up);
 401         }
 402
 403         spin_unlock(&up->port.lock);
 404
 405         return IRQ_HANDLED;
 406 }
 407
 408 static int ar933x_uart_startup(struct uart_port *port)
 409 {
 410         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 411         unsigned long flags;
 412         int ret;
 413
 414         ret = request_irq(up->port.irq, ar933x_uart_interrupt,
 415                           up->port.irqflags, dev_name(up->port.dev), up);
 416         if (ret)
 417                 return ret;
 418
 419         spin_lock_irqsave(&up->port.lock, flags);
 420
 421         /* Enable HOST interrupts */
 422         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
 423                             AR933X_UART_CS_HOST_INT_EN);
 424
 425         /* Enable RX interrupts */
 426         up->ier = AR933X_UART_INT_RX_VALID;
 427         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 428
 429         spin_unlock_irqrestore(&up->port.lock, flags);
 430
 431         return 0;
 432 }
 433
 434 static void ar933x_uart_shutdown(struct uart_port *port)
 435 {
 436         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 437
 438         /* Disable all interrupts */
 439         up->ier = 0;
 440         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, up->ier);
 441
 442         /* Disable break condition */
 443         ar933x_uart_rmw_clear(up, AR933X_UART_CS_REG,
 444                               AR933X_UART_CS_TX_BREAK);
 445
 446         free_irq(up->port.irq, up);
 447 }
 448
 449 static const char *ar933x_uart_type(struct uart_port *port)
 450 {
 451         return (port->type == PORT_AR933X) ? "AR933X UART" : NULL;
 452 }
 453
 454 static void ar933x_uart_release_port(struct uart_port *port)
 455 {
 456         /* Nothing to release ... */
 457 }
 458
 459 static int ar933x_uart_request_port(struct uart_port *port)
 460 {
 461         /* UARTs always present */
 462         return 0;
 463 }
 464
 465 static void ar933x_uart_config_port(struct uart_port *port, int flags)
 466 {
 467         if (flags & UART_CONFIG_TYPE)
 468                 port->type = PORT_AR933X;
 469 }
 470
 471 static int ar933x_uart_verify_port(struct uart_port *port,
 472                                    struct serial_struct *ser)
 473 {
 474         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 475
 476         if (ser->type != PORT_UNKNOWN &&
 477             ser->type != PORT_AR933X)
 478                 return -EINVAL;
 479
 480         if (ser->irq < 0 || ser->irq >= NR_IRQS)
 481                 return -EINVAL;
 482
 483         if (ser->baud_base < up->min_baud ||
 484             ser->baud_base > up->max_baud)
 485                 return -EINVAL;
 486
 487         return 0;
 488 }
 489
 490 static struct uart_ops ar933x_uart_ops = {
 491         .tx_empty       = ar933x_uart_tx_empty,
 492         .set_mctrl      = ar933x_uart_set_mctrl,
 493         .get_mctrl      = ar933x_uart_get_mctrl,
 494         .stop_tx        = ar933x_uart_stop_tx,
 495         .start_tx       = ar933x_uart_start_tx,
 496         .stop_rx        = ar933x_uart_stop_rx,
 497         .enable_ms      = ar933x_uart_enable_ms,
 498         .break_ctl      = ar933x_uart_break_ctl,
 499         .startup        = ar933x_uart_startup,
 500         .shutdown       = ar933x_uart_shutdown,
 501         .set_termios    = ar933x_uart_set_termios,
 502         .type           = ar933x_uart_type,
 503         .release_port   = ar933x_uart_release_port,
 504         .request_port   = ar933x_uart_request_port,
 505         .config_port    = ar933x_uart_config_port,
 506         .verify_port    = ar933x_uart_verify_port,
 507 };
 508
 509 #ifdef CONFIG_SERIAL_AR933X_CONSOLE
 510
 511 static struct ar933x_uart_port *
 512 ar933x_console_ports[CONFIG_SERIAL_AR933X_NR_UARTS];
 513
 514 static void ar933x_uart_wait_xmitr(struct ar933x_uart_port *up)
 515 {
 516         unsigned int status;
 517         unsigned int timeout = 60000;
 518
 519         /* Wait up to 60ms for the character(s) to be sent. */
 520         do {
 521                 status = ar933x_uart_read(up, AR933X_UART_DATA_REG);
 522                 if (--timeout == 0)
 523                         break;
 524                 udelay(1);
 525         } while ((status & AR933X_UART_DATA_TX_CSR) == 0);
 526 }
 527
 528 static void ar933x_uart_console_putchar(struct uart_port *port, int ch)
 529 {
 530         struct ar933x_uart_port *up = (struct ar933x_uart_port *) port;
 531
 532         ar933x_uart_wait_xmitr(up);
 533         ar933x_uart_putc(up, ch);
 534 }
 535
 536 static void ar933x_uart_console_write(struct console *co, const char *s,
 537                                       unsigned int count)
 538 {
 539         struct ar933x_uart_port *up = ar933x_console_ports[co->index];
 540         unsigned long flags;
 541         unsigned int int_en;
 542         int locked = 1;
 543
 544         local_irq_save(flags);
 545
 546         if (up->port.sysrq)
 547                 locked = 0;
 548         else if (oops_in_progress)
 549                 locked = spin_trylock(&up->port.lock);
 550         else
 551                 spin_lock(&up->port.lock);
 552
 553         /*
 554          * First save the IER then disable the interrupts
 555          */
 556         int_en = ar933x_uart_read(up, AR933X_UART_INT_EN_REG);
 557         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, 0);
 558
 559         uart_console_write(&up->port, s, count, ar933x_uart_console_putchar);
 560
 561         /*
 562          * Finally, wait for transmitter to become empty
 563          * and restore the IER
 564          */
 565         ar933x_uart_wait_xmitr(up);
 566         ar933x_uart_write(up, AR933X_UART_INT_EN_REG, int_en);
 567
 568         ar933x_uart_write(up, AR933X_UART_INT_REG, AR933X_UART_INT_ALLINTS);
 569
 570         if (locked)
 571                 spin_unlock(&up->port.lock);
 572
 573         local_irq_restore(flags);
 574 }
 575
 576 static int ar933x_uart_console_setup(struct console *co, char *options)
 577 {
 578         struct ar933x_uart_port *up;
 579         int baud = 115200;
 580         int bits = 8;
 581         int parity = 'n';
 582         int flow = 'n';
 583
 584         if (co->index < 0 || co->index >= CONFIG_SERIAL_AR933X_NR_UARTS)
 585                 return -EINVAL;
 586
 587         up = ar933x_console_ports[co->index];
 588         if (!up)
 589                 return -ENODEV;
 590
 591         if (options)
 592                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 593
 594         return uart_set_options(&up->port, co, baud, parity, bits, flow);
 595 }
 596
 597 static struct console ar933x_uart_console = {
 598         .name           = "ttyATH",
 599         .write          = ar933x_uart_console_write,
 600         .device         = uart_console_device,
 601         .setup          = ar933x_uart_console_setup,
 602         .flags          = CON_PRINTBUFFER,
 603         .index          = -1,
 604         .data           = &ar933x_uart_driver,
 605 };
 606
 607 static void ar933x_uart_add_console_port(struct ar933x_uart_port *up)
 608 {
 609         ar933x_console_ports[up->port.line] = up;
 610 }
 611
 612 #define AR933X_SERIAL_CONSOLE   (&ar933x_uart_console)
 613
 614 #else
 615
 616 static inline void ar933x_uart_add_console_port(struct ar933x_uart_port *up) {}
 617
 618 #define AR933X_SERIAL_CONSOLE   NULL
 619
 620 #endif /* CONFIG_SERIAL_AR933X_CONSOLE */
 621
 622 static struct uart_driver ar933x_uart_driver = {
 623         .owner          = THIS_MODULE,
 624         .driver_name    = DRIVER_NAME,
 625         .dev_name       = "ttyATH",
 626         .nr             = CONFIG_SERIAL_AR933X_NR_UARTS,
 627         .cons           = AR933X_SERIAL_CONSOLE,
 628 };
 629
 630 static int ar933x_uart_probe(struct platform_device *pdev)
 631 {
 632         struct ar933x_uart_platform_data *pdata;
 633         struct ar933x_uart_port *up;
 634         struct uart_port *port;
 635         struct resource *mem_res;
 636         struct resource *irq_res;
 637         unsigned int baud;
 638         int id;
 639         int ret;
 640
 641         pdata = pdev->dev.platform_data;
 642         if (!pdata)
 643                 return -EINVAL;
 644
 645         id = pdev->id;
 646         if (id == -1)
 647                 id = 0;
 648
 649         if (id > CONFIG_SERIAL_AR933X_NR_UARTS)
 650                 return -EINVAL;
 651
 652         mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 653         if (!mem_res) {
 654                 dev_err(&pdev->dev, "no MEM resource\n");
 655                 return -EINVAL;
 656         }
 657
 658         irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 659         if (!irq_res) {
 660                 dev_err(&pdev->dev, "no IRQ resource\n");
 661                 return -EINVAL;
 662         }
 663
 664         up = kzalloc(sizeof(struct ar933x_uart_port), GFP_KERNEL);
 665         if (!up)
 666                 return -ENOMEM;
 667
 668         port = &up->port;
 669         port->mapbase = mem_res->start;
 670
 671         port->membase = ioremap(mem_res->start, AR933X_UART_REGS_SIZE);
 672         if (!port->membase) {
 673                 ret = -ENOMEM;
 674                 goto err_free_up;
 675         }
 676
 677         port->line = id;
 678         port->irq = irq_res->start;
 679         port->dev = &pdev->dev;
 680         port->type = PORT_AR933X;
 681         port->iotype = UPIO_MEM32;
 682         port->uartclk = pdata->uartclk;
 683
 684         port->regshift = 2;
 685         port->fifosize = AR933X_UART_FIFO_SIZE;
 686         port->ops = &ar933x_uart_ops;
 687
 688         baud = ar933x_uart_get_baud(port->uartclk, AR933X_UART_MAX_SCALE, 1);
 689         up->min_baud = max_t(unsigned int, baud, AR933X_UART_MIN_BAUD);
 690
 691         baud = ar933x_uart_get_baud(port->uartclk, 0, AR933X_UART_MAX_STEP);
 692         up->max_baud = min_t(unsigned int, baud, AR933X_UART_MAX_BAUD);
 693
 694         ar933x_uart_add_console_port(up);
 695
 696         ret = uart_add_one_port(&ar933x_uart_driver, &up->port);
 697         if (ret)
 698                 goto err_unmap;
 699
 700         platform_set_drvdata(pdev, up);
 701         return 0;
 702
 703 err_unmap:
 704         iounmap(up->port.membase);
 705 err_free_up:
 706         kfree(up);
 707         return ret;
 708 }
 709
 710 static int ar933x_uart_remove(struct platform_device *pdev)
 711 {
 712         struct ar933x_uart_port *up;
 713
 714         up = platform_get_drvdata(pdev);
 715         platform_set_drvdata(pdev, NULL);
 716
 717         if (up) {
 718                 uart_remove_one_port(&ar933x_uart_driver, &up->port);
 719                 iounmap(up->port.membase);
 720                 kfree(up);
 721         }
 722
 723         return 0;
 724 }
 725
 726 static struct platform_driver ar933x_uart_platform_driver = {
 727         .probe          = ar933x_uart_probe,
 728         .remove         = ar933x_uart_remove,
 729         .driver         = {
 730                 .name           = DRIVER_NAME,
 731                 .owner          = THIS_MODULE,
 732         },
 733 };
 734
 735 static int __init ar933x_uart_init(void)
 736 {
 737         int ret;
 738
 739         ar933x_uart_driver.nr = CONFIG_SERIAL_AR933X_NR_UARTS;
 740         ret = uart_register_driver(&ar933x_uart_driver);
 741         if (ret)
 742                 goto err_out;
 743
 744         ret = platform_driver_register(&ar933x_uart_platform_driver);
 745         if (ret)
 746                 goto err_unregister_uart_driver;
 747
 748         return 0;
 749
 750 err_unregister_uart_driver:
 751         uart_unregister_driver(&ar933x_uart_driver);
 752 err_out:
 753         return ret;
 754 }
 755
 756 static void __exit ar933x_uart_exit(void)
 757 {
 758         platform_driver_unregister(&ar933x_uart_platform_driver);
 759         uart_unregister_driver(&ar933x_uart_driver);
 760 }
 761
 762 module_init(ar933x_uart_init);
 763 module_exit(ar933x_uart_exit);
 764
 765 MODULE_DESCRIPTION("Atheros AR933X UART driver");
 766 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
 767 MODULE_LICENSE("GPL v2");
 768 MODULE_ALIAS("platform:" DRIVER_NAME);