target/linux/amazon/files/drivers/serial/amazon_asc.c

   1 /*
   2  *  Driver for AMAZONASC serial ports
   3  *
   4  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   5  *  Based on drivers/serial/serial_s3c2400.c
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  *
  21  * Copyright (C) 2004 Infineon IFAP DC COM CPE
  22  * Copyright (C) 2007 Felix Fietkau <nbd@openwrt.org>
  23  * Copyright (C) 2007 John Crispin <blogic@openwrt.org>
  24  */
  25
  26 #include <linux/module.h>
  27 #include <linux/errno.h>
  28 #include <linux/signal.h>
  29 #include <linux/sched.h>
  30 #include <linux/interrupt.h>
  31 #include <linux/tty.h>
  32 #include <linux/tty_flip.h>
  33 #include <linux/major.h>
  34 #include <linux/string.h>
  35 #include <linux/fcntl.h>
  36 #include <linux/ptrace.h>
  37 #include <linux/ioport.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include <linux/init.h>
  41 #include <linux/circ_buf.h>
  42 #include <linux/serial.h>
  43 #include <linux/serial_core.h>
  44 #include <linux/console.h>
  45 #include <linux/sysrq.h>
  46 #include <linux/irq.h>
  47 #include <linux/platform_device.h>
  48
  49 #include <asm/system.h>
  50 #include <asm/io.h>
  51 #include <asm/uaccess.h>
  52 #include <asm/bitops.h>
  53 #include <asm/amazon/amazon.h>
  54 #include <asm/amazon/irq.h>
  55 #include <asm/amazon/serial.h>
  56
  57 #define PORT_AMAZONASC  111
  58
  59 #include <linux/serial_core.h>
  60
  61 #define UART_NR         1
  62
  63 #define UART_DUMMY_UER_RX 1
  64
  65 #define SERIAL_AMAZONASC_MAJOR  TTY_MAJOR
  66 #define CALLOUT_AMAZONASC_MAJOR TTYAUX_MAJOR
  67 #define SERIAL_AMAZONASC_MINOR  64
  68 #define SERIAL_AMAZONASC_NR     UART_NR
  69
  70 static void amazonasc_tx_chars(struct uart_port *port);
  71 static struct uart_port amazonasc_ports[UART_NR];
  72 static struct uart_driver amazonasc_reg;
  73 static unsigned int uartclk = 0;
  74
  75 static void amazonasc_stop_tx(struct uart_port *port)
  76 {
  77         /* fifo underrun shuts up after firing once */
  78         return;
  79 }
  80
  81 static void amazonasc_start_tx(struct uart_port *port)
  82 {
  83         unsigned long flags;
  84
  85         local_irq_save(flags);
  86         amazonasc_tx_chars(port);
  87         local_irq_restore(flags);
  88
  89         return;
  90 }
  91
  92 static void amazonasc_stop_rx(struct uart_port *port)
  93 {
  94         /* clear the RX enable bit */
  95         amazon_writel(ASCWHBCON_CLRREN, AMAZON_ASC_WHBCON);
  96 }
  97
  98 static void amazonasc_enable_ms(struct uart_port *port)
  99 {
 100         /* no modem signals */
 101         return;
 102 }
 103
 104 #include <linux/version.h>
 105
 106 static void
 107 amazonasc_rx_chars(struct uart_port *port)
 108 {
 109 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 31))
 110         struct tty_struct *tty = port->state->port.tty;
 111 #else
 112         struct tty_struct *tty = port->info->port.tty;
 113 #endif
 114         unsigned int ch = 0, rsr = 0, fifocnt;
 115
 116         fifocnt = amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_RXFFLMASK;
 117         while (fifocnt--)
 118         {
 119                 u8 flag = TTY_NORMAL;
 120                 ch = amazon_readl(AMAZON_ASC_RBUF);
 121                 rsr = (amazon_readl(AMAZON_ASC_CON) & ASCCON_ANY) | UART_DUMMY_UER_RX;
 122                 tty_flip_buffer_push(tty);
 123                 port->icount.rx++;
 124
 125                 /*
 126                  * Note that the error handling code is
 127                  * out of the main execution path
 128                  */
 129                 if (rsr & ASCCON_ANY) {
 130                         if (rsr & ASCCON_PE) {
 131                                 port->icount.parity++;
 132                                 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLRPE, ASCWHBCON_CLRPE);
 133                         } else if (rsr & ASCCON_FE) {
 134                                 port->icount.frame++;
 135                                 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLRFE, ASCWHBCON_CLRFE);
 136                         }
 137                         if (rsr & ASCCON_OE) {
 138                                 port->icount.overrun++;
 139                                 amazon_writel_masked(AMAZON_ASC_WHBCON, ASCWHBCON_CLROE, ASCWHBCON_CLROE);
 140                         }
 141
 142                         rsr &= port->read_status_mask;
 143
 144                         if (rsr & ASCCON_PE)
 145                                 flag = TTY_PARITY;
 146                         else if (rsr & ASCCON_FE)
 147                                 flag = TTY_FRAME;
 148                 }
 149
 150                 if ((rsr & port->ignore_status_mask) == 0)
 151                         tty_insert_flip_char(tty, ch, flag);
 152
 153                 if (rsr & ASCCON_OE)
 154                         /*
 155                          * Overrun is special, since it's reported
 156                          * immediately, and doesn't affect the current
 157                          * character
 158                          */
 159                         tty_insert_flip_char(tty, 0, TTY_OVERRUN);
 160         }
 161         if (ch != 0)
 162                 tty_flip_buffer_push(tty);
 163
 164         return;
 165 }
 166
 167
 168 static void amazonasc_tx_chars(struct uart_port *port)
 169 {
 170 #if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 31))
 171         struct circ_buf *xmit = &port->state->xmit;
 172 #else
 173         struct circ_buf *xmit = &port->info->xmit;
 174 #endif
 175
 176         if (uart_tx_stopped(port)) {
 177                 amazonasc_stop_tx(port);
 178                 return;
 179         }
 180
 181         while (((amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK)
 182                         >> ASCFSTAT_TXFFLOFF) != AMAZONASC_TXFIFO_FULL)
 183         {
 184                 if (port->x_char) {
 185                         amazon_writel(port->x_char, AMAZON_ASC_TBUF);
 186                         port->icount.tx++;
 187                         port->x_char = 0;
 188                         continue;
 189                 }
 190
 191                 if (uart_circ_empty(xmit))
 192                         break;
 193
 194                 amazon_writel(xmit->buf[xmit->tail], AMAZON_ASC_TBUF);
 195                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 196                 port->icount.tx++;
 197         }
 198
 199         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 200                 uart_write_wakeup(port);
 201 }
 202
 203 static irqreturn_t amazonasc_tx_int(int irq, void *port)
 204 {
 205         amazon_writel(ASC_IRNCR_TIR, AMAZON_ASC_IRNCR1);
 206         amazonasc_start_tx(port);
 207
 208         /* clear any pending interrupts */
 209         amazon_writel_masked(AMAZON_ASC_WHBCON,
 210                         (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE),
 211                         (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE));
 212
 213         return IRQ_HANDLED;
 214 }
 215
 216 static irqreturn_t amazonasc_er_int(int irq, void *port)
 217 {
 218         /* clear any pending interrupts */
 219         amazon_writel_masked(AMAZON_ASC_WHBCON,
 220                         (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE),
 221                         (ASCWHBCON_CLRPE | ASCWHBCON_CLRFE | ASCWHBCON_CLROE));
 222
 223         return IRQ_HANDLED;
 224 }
 225
 226 static irqreturn_t amazonasc_rx_int(int irq, void *port)
 227 {
 228         amazon_writel(ASC_IRNCR_RIR, AMAZON_ASC_IRNCR1);
 229         amazonasc_rx_chars((struct uart_port *) port);
 230         return IRQ_HANDLED;
 231 }
 232
 233 static u_int amazonasc_tx_empty(struct uart_port *port)
 234 {
 235         int status;
 236
 237         /*
 238          * FSTAT tells exactly how many bytes are in the FIFO.
 239          * The question is whether we really need to wait for all
 240          * 16 bytes to be transmitted before reporting that the
 241          * transmitter is empty.
 242          */
 243         status = amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK;
 244         return status ? 0 : TIOCSER_TEMT;
 245 }
 246
 247 static u_int amazonasc_get_mctrl(struct uart_port *port)
 248 {
 249         /* no modem control signals - the readme says to pretend all are set */
 250         return TIOCM_CTS|TIOCM_CAR|TIOCM_DSR;
 251 }
 252
 253 static void amazonasc_set_mctrl(struct uart_port *port, u_int mctrl)
 254 {
 255         /* no modem control - just return */
 256         return;
 257 }
 258
 259 static void amazonasc_break_ctl(struct uart_port *port, int break_state)
 260 {
 261         /* no way to send a break */
 262         return;
 263 }
 264
 265 static int amazonasc_startup(struct uart_port *port)
 266 {
 267         unsigned int con = 0;
 268         unsigned long flags;
 269         int retval;
 270
 271         /* this assumes: CON.BRS = CON.FDE = 0 */
 272         if (uartclk == 0)
 273                 uartclk = amazon_get_fpi_hz();
 274
 275         amazonasc_ports[0].uartclk = uartclk;
 276
 277         local_irq_save(flags);
 278
 279         /* this setup was probably already done in u-boot */
 280         /* ASC and GPIO Port 1 bits 3 and 4 share the same pins
 281          * P1.3 (RX) in, Alternate 10
 282          * P1.4 (TX) in, Alternate 10
 283          */
 284          amazon_writel_masked(AMAZON_GPIO_P1_DIR, 0x18, 0x10);  //P1.4 output, P1.3 input
 285          amazon_writel_masked(AMAZON_GPIO_P1_ALTSEL0, 0x18, 0x18);              //ALTSETL0 11
 286          amazon_writel_masked(AMAZON_GPIO_P1_ALTSEL1, 0x18, 0);         //ALTSETL1 00
 287          amazon_writel_masked(AMAZON_GPIO_P1_OD, 0x18, 0x10);
 288
 289         /* set up the CLC */
 290         amazon_writel_masked(AMAZON_ASC_CLC, AMAZON_ASC_CLC_DISS, 0);
 291         amazon_writel_masked(AMAZON_ASC_CLC, ASCCLC_RMCMASK, 1 << ASCCLC_RMCOFFSET);
 292
 293         /* asynchronous mode */
 294         con = ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_OEN | ASCCON_PEN;
 295
 296         /* choose the line - there's only one */
 297         amazon_writel(0, AMAZON_ASC_PISEL);
 298         amazon_writel(((AMAZONASC_TXFIFO_FL << ASCTXFCON_TXFITLOFF) & ASCTXFCON_TXFITLMASK) | ASCTXFCON_TXFEN | ASCTXFCON_TXFFLU,
 299                 AMAZON_ASC_TXFCON);
 300         amazon_writel(((AMAZONASC_RXFIFO_FL << ASCRXFCON_RXFITLOFF) & ASCRXFCON_RXFITLMASK) | ASCRXFCON_RXFEN | ASCRXFCON_RXFFLU,
 301                 AMAZON_ASC_RXFCON);
 302         wmb();
 303
 304         amazon_writel_masked(AMAZON_ASC_CON, con, con);
 305
 306         retval = request_irq(AMAZONASC_RIR, amazonasc_rx_int, 0, "asc_rx", port);
 307         if (retval){
 308                 printk("failed to request amazonasc_rx_int\n");
 309                 return retval;
 310         }
 311         retval = request_irq(AMAZONASC_TIR, amazonasc_tx_int, 0, "asc_tx", port);
 312         if (retval){
 313                 printk("failed to request amazonasc_tx_int\n");
 314                 goto err1;
 315         }
 316
 317         retval = request_irq(AMAZONASC_EIR, amazonasc_er_int, 0, "asc_er", port);
 318         if (retval){
 319                 printk("failed to request amazonasc_er_int\n");
 320                 goto err2;
 321         }
 322
 323         local_irq_restore(flags);
 324         return 0;
 325
 326 err2:
 327         free_irq(AMAZONASC_TIR, port);
 328
 329 err1:
 330         free_irq(AMAZONASC_RIR, port);
 331         local_irq_restore(flags);
 332         return retval;
 333 }
 334
 335 static void amazonasc_shutdown(struct uart_port *port)
 336 {
 337         free_irq(AMAZONASC_RIR, port);
 338         free_irq(AMAZONASC_TIR, port);
 339         free_irq(AMAZONASC_EIR, port);
 340         /*
 341          * disable the baudrate generator to disable the ASC
 342          */
 343         amazon_writel(0, AMAZON_ASC_CON);
 344
 345         /* flush and then disable the fifos */
 346         amazon_writel_masked(AMAZON_ASC_RXFCON, ASCRXFCON_RXFFLU, ASCRXFCON_RXFFLU);
 347         amazon_writel_masked(AMAZON_ASC_RXFCON, ASCRXFCON_RXFEN, 0);
 348         amazon_writel_masked(AMAZON_ASC_TXFCON, ASCTXFCON_TXFFLU, ASCTXFCON_TXFFLU);
 349         amazon_writel_masked(AMAZON_ASC_TXFCON, ASCTXFCON_TXFEN, 0);
 350 }
 351
 352 static void amazonasc_set_termios(struct uart_port *port, struct ktermios *new, struct ktermios *old)
 353 {
 354         unsigned int cflag;
 355         unsigned int iflag;
 356         unsigned int baud, quot;
 357         unsigned int con = 0;
 358         unsigned long flags;
 359
 360         cflag = new->c_cflag;
 361         iflag = new->c_iflag;
 362
 363         /* byte size and parity */
 364         switch (cflag & CSIZE) {
 365         /* 7 bits are always with parity */
 366         case CS7: con = ASCCON_M_7ASYNCPAR; break;
 367         /* the ASC only suports 7 and 8 bits */
 368         case CS5:
 369         case CS6:
 370         default:
 371                 if (cflag & PARENB)
 372                         con = ASCCON_M_8ASYNCPAR;
 373                 else
 374                         con = ASCCON_M_8ASYNC;
 375                 break;
 376         }
 377         if (cflag & CSTOPB)
 378                 con |= ASCCON_STP;
 379         if (cflag & PARENB) {
 380                 if (!(cflag & PARODD))
 381                         con &= ~ASCCON_ODD;
 382                 else
 383                         con |= ASCCON_ODD;
 384         }
 385
 386         port->read_status_mask = ASCCON_OE;
 387         if (iflag & INPCK)
 388                 port->read_status_mask |= ASCCON_FE | ASCCON_PE;
 389
 390         port->ignore_status_mask = 0;
 391         if (iflag & IGNPAR)
 392                 port->ignore_status_mask |= ASCCON_FE | ASCCON_PE;
 393
 394         if (iflag & IGNBRK) {
 395                 /*
 396                  * If we're ignoring parity and break indicators,
 397                  * ignore overruns too (for real raw support).
 398                  */
 399                 if (iflag & IGNPAR)
 400                         port->ignore_status_mask |= ASCCON_OE;
 401         }
 402
 403         /*
 404          * Ignore all characters if CREAD is not set.
 405          */
 406         if ((cflag & CREAD) == 0)
 407                 port->ignore_status_mask |= UART_DUMMY_UER_RX;
 408
 409         /* set error signals  - framing, parity  and overrun */
 410         con |= ASCCON_FEN;
 411         con |= ASCCON_OEN;
 412         con |= ASCCON_PEN;
 413         /* enable the receiver */
 414         con |= ASCCON_REN;
 415
 416         /* block the IRQs */
 417         local_irq_save(flags);
 418
 419         /* set up CON */
 420         amazon_writel(con, AMAZON_ASC_CON);
 421
 422         /* Set baud rate - take a divider of 2 into account */
 423     baud = uart_get_baud_rate(port, new, old, 0, port->uartclk/16);
 424         quot = uart_get_divisor(port, baud);
 425         quot = quot/2 - 1;
 426
 427         /* the next 3 probably already happened when we set CON above */
 428         /* disable the baudrate generator */
 429         amazon_writel_masked(AMAZON_ASC_CON, ASCCON_R, 0);
 430         /* make sure the fractional divider is off */
 431         amazon_writel_masked(AMAZON_ASC_CON, ASCCON_FDE, 0);
 432         /* set up to use divisor of 2 */
 433         amazon_writel_masked(AMAZON_ASC_CON, ASCCON_BRS, 0);
 434         /* now we can write the new baudrate into the register */
 435         amazon_writel(quot, AMAZON_ASC_BTR);
 436         /* turn the baudrate generator back on */
 437         amazon_writel_masked(AMAZON_ASC_CON, ASCCON_R, ASCCON_R);
 438
 439         local_irq_restore(flags);
 440 }
 441
 442 static const char *amazonasc_type(struct uart_port *port)
 443 {
 444         return port->type == PORT_AMAZONASC ? "AMAZONASC" : NULL;
 445 }
 446
 447 /*
 448  * Release the memory region(s) being used by 'port'
 449  */
 450 static void amazonasc_release_port(struct uart_port *port)
 451 {
 452         return;
 453 }
 454
 455 /*
 456  * Request the memory region(s) being used by 'port'
 457  */
 458 static int amazonasc_request_port(struct uart_port *port)
 459 {
 460         return 0;
 461 }
 462
 463 /*
 464  * Configure/autoconfigure the port.
 465  */
 466 static void amazonasc_config_port(struct uart_port *port, int flags)
 467 {
 468         if (flags & UART_CONFIG_TYPE) {
 469                 port->type = PORT_AMAZONASC;
 470                 amazonasc_request_port(port);
 471         }
 472 }
 473
 474 /*
 475  * verify the new serial_struct (for TIOCSSERIAL).
 476  */
 477 static int amazonasc_verify_port(struct uart_port *port, struct serial_struct *ser)
 478 {
 479         int ret = 0;
 480         if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMAZONASC)
 481                 ret = -EINVAL;
 482         if (ser->irq < 0 || ser->irq >= NR_IRQS)
 483                 ret = -EINVAL;
 484         if (ser->baud_base < 9600)
 485                 ret = -EINVAL;
 486         return ret;
 487 }
 488
 489 static struct uart_ops amazonasc_pops = {
 490         .tx_empty =             amazonasc_tx_empty,
 491         .set_mctrl =    amazonasc_set_mctrl,
 492         .get_mctrl =    amazonasc_get_mctrl,
 493         .stop_tx =              amazonasc_stop_tx,
 494         .start_tx =             amazonasc_start_tx,
 495         .stop_rx =              amazonasc_stop_rx,
 496         .enable_ms =    amazonasc_enable_ms,
 497         .break_ctl =    amazonasc_break_ctl,
 498         .startup =              amazonasc_startup,
 499         .shutdown =             amazonasc_shutdown,
 500         .set_termios =  amazonasc_set_termios,
 501         .type =                 amazonasc_type,
 502         .release_port = amazonasc_release_port,
 503         .request_port = amazonasc_request_port,
 504         .config_port =  amazonasc_config_port,
 505         .verify_port =  amazonasc_verify_port,
 506 };
 507
 508 static struct uart_port amazonasc_ports[UART_NR] = {
 509         {
 510                 membase:        (void *)AMAZON_ASC,
 511                 mapbase:        AMAZON_ASC,
 512                 iotype:         SERIAL_IO_MEM,
 513                 irq:            AMAZONASC_RIR, /* RIR */
 514                 uartclk:        0, /* filled in dynamically */
 515                 fifosize:       16,
 516                 unused:         { AMAZONASC_TIR, AMAZONASC_EIR}, /* xmit/error/xmit-buffer-empty IRQ */
 517                 type:           PORT_AMAZONASC,
 518                 ops:            &amazonasc_pops,
 519                 flags:          ASYNC_BOOT_AUTOCONF,
 520         },
 521 };
 522
 523 static void amazonasc_console_write(struct console *co, const char *s, u_int count)
 524 {
 525         int i, fifocnt;
 526         unsigned long flags;
 527         local_irq_save(flags);
 528         for (i = 0; i < count;)
 529         {
 530                 /* wait until the FIFO is not full */
 531                 do
 532                 {
 533                         fifocnt = (amazon_readl(AMAZON_ASC_FSTAT) & ASCFSTAT_TXFFLMASK)
 534                                         >> ASCFSTAT_TXFFLOFF;
 535                 } while (fifocnt == AMAZONASC_TXFIFO_FULL);
 536                 if (s[i] == '\0')
 537                 {
 538                         break;
 539                 }
 540                 if (s[i] == '\n')
 541                 {
 542                         amazon_writel('\r', AMAZON_ASC_TBUF);
 543                         do
 544                         {
 545                                 fifocnt = (amazon_readl(AMAZON_ASC_FSTAT) &
 546                                 ASCFSTAT_TXFFLMASK) >> ASCFSTAT_TXFFLOFF;
 547                         } while (fifocnt == AMAZONASC_TXFIFO_FULL);
 548                 }
 549                 amazon_writel(s[i], AMAZON_ASC_TBUF);
 550                 i++;
 551         }
 552
 553         local_irq_restore(flags);
 554 }
 555
 556 static void __init
 557 amazonasc_console_get_options(struct uart_port *port, int *baud, int *parity, int *bits)
 558 {
 559         u_int lcr_h;
 560
 561         lcr_h = amazon_readl(AMAZON_ASC_CON);
 562         /* do this only if the ASC is turned on */
 563         if (lcr_h & ASCCON_R) {
 564                 u_int quot, div, fdiv, frac;
 565
 566                 *parity = 'n';
 567                 if ((lcr_h & ASCCON_MODEMASK) == ASCCON_M_7ASYNCPAR ||
 568                             (lcr_h & ASCCON_MODEMASK) == ASCCON_M_8ASYNCPAR) {
 569                         if (lcr_h & ASCCON_ODD)
 570                                 *parity = 'o';
 571                         else
 572                                 *parity = 'e';
 573                 }
 574
 575                 if ((lcr_h & ASCCON_MODEMASK) == ASCCON_M_7ASYNCPAR)
 576                         *bits = 7;
 577                 else
 578                         *bits = 8;
 579
 580                 quot = amazon_readl(AMAZON_ASC_BTR) + 1;
 581
 582                 /* this gets hairy if the fractional divider is used */
 583                 if (lcr_h & ASCCON_FDE)
 584                 {
 585                         div = 1;
 586                         fdiv = amazon_readl(AMAZON_ASC_FDV);
 587                         if (fdiv == 0)
 588                                 fdiv = 512;
 589                         frac = 512;
 590                 }
 591                 else
 592                 {
 593                         div = lcr_h & ASCCON_BRS ? 3 : 2;
 594                         fdiv = frac = 1;
 595                 }
 596                 /*
 597                  * This doesn't work exactly because we use integer
 598                  * math to calculate baud which results in rounding
 599                  * errors when we try to go from quot -> baud !!
 600                  * Try to make this work for both the fractional divider
 601                  * and the simple divider. Also try to avoid rounding
 602                  * errors using integer math.
 603                  */
 604
 605                 *baud = frac * (port->uartclk / (div * 512 * 16 * quot));
 606                 if (*baud > 1100 && *baud < 2400)
 607                         *baud = 1200;
 608                 if (*baud > 2300 && *baud < 4800)
 609                         *baud = 2400;
 610                 if (*baud > 4700 && *baud < 9600)
 611                         *baud = 4800;
 612                 if (*baud > 9500 && *baud < 19200)
 613                         *baud = 9600;
 614                 if (*baud > 19000 && *baud < 38400)
 615                         *baud = 19200;
 616                 if (*baud > 38400 && *baud < 57600)
 617                         *baud = 38400;
 618                 if (*baud > 57600 && *baud < 115200)
 619                         *baud = 57600;
 620                 if (*baud > 115200 && *baud < 230400)
 621                         *baud = 115200;
 622         }
 623 }
 624
 625 static int __init amazonasc_console_setup(struct console *co, char *options)
 626 {
 627         struct uart_port *port;
 628         int baud = 115200;
 629         int bits = 8;
 630         int parity = 'n';
 631         int flow = 'n';
 632
 633         /* this assumes: CON.BRS = CON.FDE = 0 */
 634         if (uartclk == 0)
 635                 uartclk = amazon_get_fpi_hz();
 636         co->index = 0;
 637         port = &amazonasc_ports[0];
 638         amazonasc_ports[0].uartclk = uartclk;
 639         amazonasc_ports[0].type = PORT_AMAZONASC;
 640
 641         if (options){
 642                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 643         }
 644
 645         return uart_set_options(port, co, baud, parity, bits, flow);
 646 }
 647
 648 static struct uart_driver amazonasc_reg;
 649 static struct console amazonasc_console = {
 650         name:           "ttyS",
 651         write:          amazonasc_console_write,
 652         device:         uart_console_device,
 653         setup:          amazonasc_console_setup,
 654         flags:          CON_PRINTBUFFER,
 655         index:          -1,
 656         data:           &amazonasc_reg,
 657 };
 658
 659 static struct uart_driver amazonasc_reg = {
 660         .owner =                        THIS_MODULE,
 661         .driver_name =          "serial",
 662         .dev_name =                     "ttyS",
 663         .major =                        TTY_MAJOR,
 664         .minor =                        64,
 665         .nr =                           UART_NR,
 666         .cons =                         &amazonasc_console,
 667 };
 668
 669 static int __init amazon_asc_probe(struct platform_device *dev)
 670 {
 671         unsigned char res;
 672         uart_register_driver(&amazonasc_reg);
 673         res = uart_add_one_port(&amazonasc_reg, &amazonasc_ports[0]);
 674         return res;
 675 }
 676
 677 static int amazon_asc_remove(struct platform_device *dev)
 678 {
 679         uart_unregister_driver(&amazonasc_reg);
 680         return 0;
 681 }
 682
 683 static struct platform_driver amazon_asc_driver = {
 684         .probe = amazon_asc_probe,
 685         .remove = amazon_asc_remove,
 686         .driver = {
 687                 .name = "amazon_asc",
 688                 .owner = THIS_MODULE,
 689         },
 690 };
 691
 692 static int __init amazon_asc_init(void)
 693 {
 694         int ret = platform_driver_register(&amazon_asc_driver);
 695         if (ret)
 696                 printk(KERN_WARNING "amazon_asc: error registering platfom driver!\n");
 697         return ret;
 698 }
 699
 700 static void __exit amazon_asc_cleanup(void)
 701 {
 702         platform_driver_unregister(&amazon_asc_driver);
 703 }
 704
 705 module_init(amazon_asc_init);
 706 module_exit(amazon_asc_cleanup);
 707
 708 MODULE_AUTHOR("Gary Jennejohn, Felix Fietkau, John Crispin");
 709 MODULE_DESCRIPTION("MIPS AMAZONASC serial port driver");
 710 MODULE_LICENSE("GPL");
 711