drivers/tty/serial/8250/8250_omap.c

   1 /*
   2  * 8250-core based driver for the OMAP internal UART
   3  *
   4  * based on omap-serial.c, Copyright (C) 2010 Texas Instruments.
   5  *
   6  * Copyright (C) 2014 Sebastian Andrzej Siewior
   7  *
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/io.h>
  12 #include <linux/module.h>
  13 #include <linux/serial_8250.h>
  14 #include <linux/serial_reg.h>
  15 #include <linux/tty_flip.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/slab.h>
  18 #include <linux/of.h>
  19 #include <linux/of_gpio.h>
  20 #include <linux/of_irq.h>
  21 #include <linux/delay.h>
  22 #include <linux/pm_runtime.h>
  23 #include <linux/console.h>
  24 #include <linux/pm_qos.h>
  25 #include <linux/dma-mapping.h>
  26
  27 #include "8250.h"
  28
  29 #define DEFAULT_CLK_SPEED       48000000
  30
  31 #define UART_ERRATA_i202_MDR1_ACCESS    (1 << 0)
  32 #define OMAP_UART_WER_HAS_TX_WAKEUP     (1 << 1)
  33 #define OMAP_DMA_TX_KICK                (1 << 2)
  34
  35 #define OMAP_UART_FCR_RX_TRIG           6
  36 #define OMAP_UART_FCR_TX_TRIG           4
  37
  38 /* SCR register bitmasks */
  39 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK       (1 << 7)
  40 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK       (1 << 6)
  41 #define OMAP_UART_SCR_TX_EMPTY                  (1 << 3)
  42 #define OMAP_UART_SCR_DMAMODE_MASK              (3 << 1)
  43 #define OMAP_UART_SCR_DMAMODE_1                 (1 << 1)
  44 #define OMAP_UART_SCR_DMAMODE_CTL               (1 << 0)
  45
  46 /* MVR register bitmasks */
  47 #define OMAP_UART_MVR_SCHEME_SHIFT      30
  48 #define OMAP_UART_LEGACY_MVR_MAJ_MASK   0xf0
  49 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT  4
  50 #define OMAP_UART_LEGACY_MVR_MIN_MASK   0x0f
  51 #define OMAP_UART_MVR_MAJ_MASK          0x700
  52 #define OMAP_UART_MVR_MAJ_SHIFT         8
  53 #define OMAP_UART_MVR_MIN_MASK          0x3f
  54
  55 #define UART_TI752_TLR_TX       0
  56 #define UART_TI752_TLR_RX       4
  57
  58 #define TRIGGER_TLR_MASK(x)     ((x & 0x3c) >> 2)
  59 #define TRIGGER_FCR_MASK(x)     (x & 3)
  60
  61 /* Enable XON/XOFF flow control on output */
  62 #define OMAP_UART_SW_TX         0x08
  63 /* Enable XON/XOFF flow control on input */
  64 #define OMAP_UART_SW_RX         0x02
  65
  66 #define OMAP_UART_WER_MOD_WKUP  0x7f
  67 #define OMAP_UART_TX_WAKEUP_EN  (1 << 7)
  68
  69 #define TX_TRIGGER      1
  70 #define RX_TRIGGER      48
  71
  72 #define OMAP_UART_TCR_RESTORE(x)        ((x / 4) << 4)
  73 #define OMAP_UART_TCR_HALT(x)           ((x / 4) << 0)
  74
  75 #define UART_BUILD_REVISION(x, y)       (((x) << 8) | (y))
  76
  77 #define OMAP_UART_REV_46 0x0406
  78 #define OMAP_UART_REV_52 0x0502
  79 #define OMAP_UART_REV_63 0x0603
  80
  81 struct omap8250_priv {
  82         int line;
  83         u8 habit;
  84         u8 mdr1;
  85         u8 efr;
  86         u8 scr;
  87         u8 wer;
  88         u8 xon;
  89         u8 xoff;
  90         u8 delayed_restore;
  91         u16 quot;
  92
  93         bool is_suspending;
  94         int wakeirq;
  95         int wakeups_enabled;
  96         u32 latency;
  97         u32 calc_latency;
  98         struct pm_qos_request pm_qos_request;
  99         struct work_struct qos_work;
 100         struct uart_8250_dma omap8250_dma;
 101 };
 102
 103 static u32 uart_read(struct uart_8250_port *up, u32 reg)
 104 {
 105         return readl(up->port.membase + (reg << up->port.regshift));
 106 }
 107
 108 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
 109 {
 110         struct uart_8250_port *up = up_to_u8250p(port);
 111         struct omap8250_priv *priv = up->port.private_data;
 112         u8 lcr;
 113
 114         serial8250_do_set_mctrl(port, mctrl);
 115
 116         /*
 117          * Turn off autoRTS if RTS is lowered and restore autoRTS setting
 118          * if RTS is raised
 119          */
 120         lcr = serial_in(up, UART_LCR);
 121         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 122         if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
 123                 priv->efr |= UART_EFR_RTS;
 124         else
 125                 priv->efr &= ~UART_EFR_RTS;
 126         serial_out(up, UART_EFR, priv->efr);
 127         serial_out(up, UART_LCR, lcr);
 128 }
 129
 130 /*
 131  * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
 132  * The access to uart register after MDR1 Access
 133  * causes UART to corrupt data.
 134  *
 135  * Need a delay =
 136  * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
 137  * give 10 times as much
 138  */
 139 static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
 140                                      struct omap8250_priv *priv)
 141 {
 142         u8 timeout = 255;
 143         u8 old_mdr1;
 144
 145         old_mdr1 = serial_in(up, UART_OMAP_MDR1);
 146         if (old_mdr1 == priv->mdr1)
 147                 return;
 148
 149         serial_out(up, UART_OMAP_MDR1, priv->mdr1);
 150         udelay(2);
 151         serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
 152                         UART_FCR_CLEAR_RCVR);
 153         /*
 154          * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
 155          * TX_FIFO_E bit is 1.
 156          */
 157         while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
 158                                 (UART_LSR_THRE | UART_LSR_DR))) {
 159                 timeout--;
 160                 if (!timeout) {
 161                         /* Should *never* happen. we warn and carry on */
 162                         dev_crit(up->port.dev, "Errata i202: timedout %x\n",
 163                                  serial_in(up, UART_LSR));
 164                         break;
 165                 }
 166                 udelay(1);
 167         }
 168 }
 169
 170 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
 171                                   struct omap8250_priv *priv)
 172 {
 173         unsigned int uartclk = port->uartclk;
 174         unsigned int div_13, div_16;
 175         unsigned int abs_d13, abs_d16;
 176
 177         /*
 178          * Old custom speed handling.
 179          */
 180         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
 181                 priv->quot = port->custom_divisor & 0xffff;
 182                 /*
 183                  * I assume that nobody is using this. But hey, if somebody
 184                  * would like to specify the divisor _and_ the mode then the
 185                  * driver is ready and waiting for it.
 186                  */
 187                 if (port->custom_divisor & (1 << 16))
 188                         priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
 189                 else
 190                         priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
 191                 return;
 192         }
 193         div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
 194         div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
 195
 196         if (!div_13)
 197                 div_13 = 1;
 198         if (!div_16)
 199                 div_16 = 1;
 200
 201         abs_d13 = abs(baud - uartclk / 13 / div_13);
 202         abs_d16 = abs(baud - uartclk / 16 / div_16);
 203
 204         if (abs_d13 >= abs_d16) {
 205                 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
 206                 priv->quot = div_16;
 207         } else {
 208                 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
 209                 priv->quot = div_13;
 210         }
 211 }
 212
 213 static void omap8250_update_scr(struct uart_8250_port *up,
 214                                 struct omap8250_priv *priv)
 215 {
 216         u8 old_scr;
 217
 218         old_scr = serial_in(up, UART_OMAP_SCR);
 219         if (old_scr == priv->scr)
 220                 return;
 221
 222         /*
 223          * The manual recommends not to enable the DMA mode selector in the SCR
 224          * (instead of the FCR) register _and_ selecting the DMA mode as one
 225          * register write because this may lead to malfunction.
 226          */
 227         if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
 228                 serial_out(up, UART_OMAP_SCR,
 229                            priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
 230         serial_out(up, UART_OMAP_SCR, priv->scr);
 231 }
 232
 233 static void omap8250_restore_regs(struct uart_8250_port *up)
 234 {
 235         struct omap8250_priv *priv = up->port.private_data;
 236         struct uart_8250_dma    *dma = up->dma;
 237
 238         if (dma && dma->tx_running) {
 239                 /*
 240                  * TCSANOW requests the change to occur immediately however if
 241                  * we have a TX-DMA operation in progress then it has been
 242                  * observed that it might stall and never complete. Therefore we
 243                  * delay DMA completes to prevent this hang from happen.
 244                  */
 245                 priv->delayed_restore = 1;
 246                 return;
 247         }
 248
 249         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 250         serial_out(up, UART_EFR, UART_EFR_ECB);
 251
 252         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
 253         serial_out(up, UART_MCR, UART_MCR_TCRTLR);
 254         serial_out(up, UART_FCR, up->fcr);
 255
 256         omap8250_update_scr(up, priv);
 257
 258         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 259
 260         serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
 261                         OMAP_UART_TCR_HALT(52));
 262         serial_out(up, UART_TI752_TLR,
 263                    TRIGGER_TLR_MASK(TX_TRIGGER) << UART_TI752_TLR_TX |
 264                    TRIGGER_TLR_MASK(RX_TRIGGER) << UART_TI752_TLR_RX);
 265
 266         serial_out(up, UART_LCR, 0);
 267
 268         /* drop TCR + TLR access, we setup XON/XOFF later */
 269         serial_out(up, UART_MCR, up->mcr);
 270         serial_out(up, UART_IER, up->ier);
 271
 272         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 273         serial_dl_write(up, priv->quot);
 274
 275         serial_out(up, UART_EFR, priv->efr);
 276
 277         /* Configure flow control */
 278         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 279         serial_out(up, UART_XON1, priv->xon);
 280         serial_out(up, UART_XOFF1, priv->xoff);
 281
 282         serial_out(up, UART_LCR, up->lcr);
 283         /* need mode A for FCR */
 284         if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
 285                 omap_8250_mdr1_errataset(up, priv);
 286         else
 287                 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
 288         up->port.ops->set_mctrl(&up->port, up->port.mctrl);
 289 }
 290
 291 /*
 292  * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
 293  * some differences in how we want to handle flow control.
 294  */
 295 static void omap_8250_set_termios(struct uart_port *port,
 296                                   struct ktermios *termios,
 297                                   struct ktermios *old)
 298 {
 299         struct uart_8250_port *up =
 300                 container_of(port, struct uart_8250_port, port);
 301         struct omap8250_priv *priv = up->port.private_data;
 302         unsigned char cval = 0;
 303         unsigned int baud;
 304
 305         switch (termios->c_cflag & CSIZE) {
 306         case CS5:
 307                 cval = UART_LCR_WLEN5;
 308                 break;
 309         case CS6:
 310                 cval = UART_LCR_WLEN6;
 311                 break;
 312         case CS7:
 313                 cval = UART_LCR_WLEN7;
 314                 break;
 315         default:
 316         case CS8:
 317                 cval = UART_LCR_WLEN8;
 318                 break;
 319         }
 320
 321         if (termios->c_cflag & CSTOPB)
 322                 cval |= UART_LCR_STOP;
 323         if (termios->c_cflag & PARENB)
 324                 cval |= UART_LCR_PARITY;
 325         if (!(termios->c_cflag & PARODD))
 326                 cval |= UART_LCR_EPAR;
 327         if (termios->c_cflag & CMSPAR)
 328                 cval |= UART_LCR_SPAR;
 329
 330         /*
 331          * Ask the core to calculate the divisor for us.
 332          */
 333         baud = uart_get_baud_rate(port, termios, old,
 334                                   port->uartclk / 16 / 0xffff,
 335                                   port->uartclk / 13);
 336         omap_8250_get_divisor(port, baud, priv);
 337
 338         /*
 339          * Ok, we're now changing the port state. Do it with
 340          * interrupts disabled.
 341          */
 342         pm_runtime_get_sync(port->dev);
 343         spin_lock_irq(&port->lock);
 344
 345         /*
 346          * Update the per-port timeout.
 347          */
 348         uart_update_timeout(port, termios->c_cflag, baud);
 349
 350         up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
 351         if (termios->c_iflag & INPCK)
 352                 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
 353         if (termios->c_iflag & (IGNBRK | PARMRK))
 354                 up->port.read_status_mask |= UART_LSR_BI;
 355
 356         /*
 357          * Characters to ignore
 358          */
 359         up->port.ignore_status_mask = 0;
 360         if (termios->c_iflag & IGNPAR)
 361                 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
 362         if (termios->c_iflag & IGNBRK) {
 363                 up->port.ignore_status_mask |= UART_LSR_BI;
 364                 /*
 365                  * If we're ignoring parity and break indicators,
 366                  * ignore overruns too (for real raw support).
 367                  */
 368                 if (termios->c_iflag & IGNPAR)
 369                         up->port.ignore_status_mask |= UART_LSR_OE;
 370         }
 371
 372         /*
 373          * ignore all characters if CREAD is not set
 374          */
 375         if ((termios->c_cflag & CREAD) == 0)
 376                 up->port.ignore_status_mask |= UART_LSR_DR;
 377
 378         /*
 379          * Modem status interrupts
 380          */
 381         up->ier &= ~UART_IER_MSI;
 382         if (UART_ENABLE_MS(&up->port, termios->c_cflag))
 383                 up->ier |= UART_IER_MSI;
 384
 385         up->lcr = cval;
 386         /* Up to here it was mostly serial8250_do_set_termios() */
 387
 388         /*
 389          * We enable TRIG_GRANU for RX and TX and additionaly we set
 390          * SCR_TX_EMPTY bit. The result is the following:
 391          * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
 392          * - less than RX_TRIGGER number of bytes will also cause an interrupt
 393          *   once the UART decides that there no new bytes arriving.
 394          * - Once THRE is enabled, the interrupt will be fired once the FIFO is
 395          *   empty - the trigger level is ignored here.
 396          *
 397          * Once DMA is enabled:
 398          * - UART will assert the TX DMA line once there is room for TX_TRIGGER
 399          *   bytes in the TX FIFO. On each assert the DMA engine will move
 400          *   TX_TRIGGER bytes into the FIFO.
 401          * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
 402          *   the FIFO and move RX_TRIGGER bytes.
 403          * This is because threshold and trigger values are the same.
 404          */
 405         up->fcr = UART_FCR_ENABLE_FIFO;
 406         up->fcr |= TRIGGER_FCR_MASK(TX_TRIGGER) << OMAP_UART_FCR_TX_TRIG;
 407         up->fcr |= TRIGGER_FCR_MASK(RX_TRIGGER) << OMAP_UART_FCR_RX_TRIG;
 408
 409         priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
 410                 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
 411
 412         if (up->dma)
 413                 priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
 414                         OMAP_UART_SCR_DMAMODE_CTL;
 415
 416         priv->xon = termios->c_cc[VSTART];
 417         priv->xoff = termios->c_cc[VSTOP];
 418
 419         priv->efr = 0;
 420         up->mcr &= ~(UART_MCR_RTS | UART_MCR_XONANY);
 421         up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
 422
 423         if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW) {
 424                 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
 425                 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
 426                 priv->efr |= UART_EFR_CTS;
 427         } else  if (up->port.flags & UPF_SOFT_FLOW) {
 428                 /*
 429                  * IXON Flag:
 430                  * Enable XON/XOFF flow control on input.
 431                  * Receiver compares XON1, XOFF1.
 432                  */
 433                 if (termios->c_iflag & IXON)
 434                         priv->efr |= OMAP_UART_SW_RX;
 435
 436                 /*
 437                  * IXOFF Flag:
 438                  * Enable XON/XOFF flow control on output.
 439                  * Transmit XON1, XOFF1
 440                  */
 441                 if (termios->c_iflag & IXOFF) {
 442                         up->port.status |= UPSTAT_AUTOXOFF;
 443                         priv->efr |= OMAP_UART_SW_TX;
 444                 }
 445
 446                 /*
 447                  * IXANY Flag:
 448                  * Enable any character to restart output.
 449                  * Operation resumes after receiving any
 450                  * character after recognition of the XOFF character
 451                  */
 452                 if (termios->c_iflag & IXANY)
 453                         up->mcr |= UART_MCR_XONANY;
 454         }
 455         omap8250_restore_regs(up);
 456
 457         spin_unlock_irq(&up->port.lock);
 458         pm_runtime_mark_last_busy(port->dev);
 459         pm_runtime_put_autosuspend(port->dev);
 460
 461         /* calculate wakeup latency constraint */
 462         priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
 463         priv->latency = priv->calc_latency;
 464
 465         schedule_work(&priv->qos_work);
 466
 467         /* Don't rewrite B0 */
 468         if (tty_termios_baud_rate(termios))
 469                 tty_termios_encode_baud_rate(termios, baud, baud);
 470 }
 471
 472 /* same as 8250 except that we may have extra flow bits set in EFR */
 473 static void omap_8250_pm(struct uart_port *port, unsigned int state,
 474                          unsigned int oldstate)
 475 {
 476         struct uart_8250_port *up = up_to_u8250p(port);
 477         u8 efr;
 478
 479         pm_runtime_get_sync(port->dev);
 480         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 481         efr = serial_in(up, UART_EFR);
 482         serial_out(up, UART_EFR, efr | UART_EFR_ECB);
 483         serial_out(up, UART_LCR, 0);
 484
 485         serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
 486         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 487         serial_out(up, UART_EFR, efr);
 488         serial_out(up, UART_LCR, 0);
 489
 490         pm_runtime_mark_last_busy(port->dev);
 491         pm_runtime_put_autosuspend(port->dev);
 492 }
 493
 494 static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
 495                                               struct omap8250_priv *priv)
 496 {
 497         u32 mvr, scheme;
 498         u16 revision, major, minor;
 499
 500         mvr = uart_read(up, UART_OMAP_MVER);
 501
 502         /* Check revision register scheme */
 503         scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
 504
 505         switch (scheme) {
 506         case 0: /* Legacy Scheme: OMAP2/3 */
 507                 /* MINOR_REV[0:4], MAJOR_REV[4:7] */
 508                 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
 509                         OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
 510                 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
 511                 break;
 512         case 1:
 513                 /* New Scheme: OMAP4+ */
 514                 /* MINOR_REV[0:5], MAJOR_REV[8:10] */
 515                 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
 516                         OMAP_UART_MVR_MAJ_SHIFT;
 517                 minor = (mvr & OMAP_UART_MVR_MIN_MASK);
 518                 break;
 519         default:
 520                 dev_warn(up->port.dev,
 521                          "Unknown revision, defaulting to highest\n");
 522                 /* highest possible revision */
 523                 major = 0xff;
 524                 minor = 0xff;
 525         }
 526         /* normalize revision for the driver */
 527         revision = UART_BUILD_REVISION(major, minor);
 528
 529         switch (revision) {
 530         case OMAP_UART_REV_46:
 531                 priv->habit = UART_ERRATA_i202_MDR1_ACCESS;
 532                 break;
 533         case OMAP_UART_REV_52:
 534                 priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
 535                                 OMAP_UART_WER_HAS_TX_WAKEUP;
 536                 break;
 537         case OMAP_UART_REV_63:
 538                 priv->habit = UART_ERRATA_i202_MDR1_ACCESS |
 539                         OMAP_UART_WER_HAS_TX_WAKEUP;
 540                 break;
 541         default:
 542                 break;
 543         }
 544 }
 545
 546 static void omap8250_uart_qos_work(struct work_struct *work)
 547 {
 548         struct omap8250_priv *priv;
 549
 550         priv = container_of(work, struct omap8250_priv, qos_work);
 551         pm_qos_update_request(&priv->pm_qos_request, priv->latency);
 552 }
 553
 554 static irqreturn_t omap_wake_irq(int irq, void *dev_id)
 555 {
 556         struct uart_port *port = dev_id;
 557         int ret;
 558
 559         ret = port->handle_irq(port);
 560         if (ret)
 561                 return IRQ_HANDLED;
 562         return IRQ_NONE;
 563 }
 564
 565 static int omap_8250_startup(struct uart_port *port)
 566 {
 567         struct uart_8250_port *up =
 568                 container_of(port, struct uart_8250_port, port);
 569         struct omap8250_priv *priv = port->private_data;
 570
 571         int ret;
 572
 573         if (priv->wakeirq) {
 574                 ret = request_irq(priv->wakeirq, omap_wake_irq,
 575                                   port->irqflags, "uart wakeup irq", port);
 576                 if (ret)
 577                         return ret;
 578                 disable_irq(priv->wakeirq);
 579         }
 580
 581         pm_runtime_get_sync(port->dev);
 582
 583         ret = serial8250_do_startup(port);
 584         if (ret)
 585                 goto err;
 586
 587 #ifdef CONFIG_PM
 588         up->capabilities |= UART_CAP_RPM;
 589 #endif
 590
 591         /* Enable module level wake up */
 592         priv->wer = OMAP_UART_WER_MOD_WKUP;
 593         if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
 594                 priv->wer |= OMAP_UART_TX_WAKEUP_EN;
 595         serial_out(up, UART_OMAP_WER, priv->wer);
 596
 597         if (up->dma)
 598                 up->dma->rx_dma(up, 0);
 599
 600         pm_runtime_mark_last_busy(port->dev);
 601         pm_runtime_put_autosuspend(port->dev);
 602         return 0;
 603 err:
 604         pm_runtime_mark_last_busy(port->dev);
 605         pm_runtime_put_autosuspend(port->dev);
 606         if (priv->wakeirq)
 607                 free_irq(priv->wakeirq, port);
 608         return ret;
 609 }
 610
 611 static void omap_8250_shutdown(struct uart_port *port)
 612 {
 613         struct uart_8250_port *up =
 614                 container_of(port, struct uart_8250_port, port);
 615         struct omap8250_priv *priv = port->private_data;
 616
 617         flush_work(&priv->qos_work);
 618         if (up->dma)
 619                 up->dma->rx_dma(up, UART_IIR_RX_TIMEOUT);
 620
 621         pm_runtime_get_sync(port->dev);
 622
 623         serial_out(up, UART_OMAP_WER, 0);
 624         serial8250_do_shutdown(port);
 625
 626         pm_runtime_mark_last_busy(port->dev);
 627         pm_runtime_put_autosuspend(port->dev);
 628
 629         if (priv->wakeirq)
 630                 free_irq(priv->wakeirq, port);
 631 }
 632
 633 static void omap_8250_throttle(struct uart_port *port)
 634 {
 635         unsigned long flags;
 636         struct uart_8250_port *up =
 637                 container_of(port, struct uart_8250_port, port);
 638
 639         pm_runtime_get_sync(port->dev);
 640
 641         spin_lock_irqsave(&port->lock, flags);
 642         up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
 643         serial_out(up, UART_IER, up->ier);
 644         spin_unlock_irqrestore(&port->lock, flags);
 645
 646         pm_runtime_mark_last_busy(port->dev);
 647         pm_runtime_put_autosuspend(port->dev);
 648 }
 649
 650 static void omap_8250_unthrottle(struct uart_port *port)
 651 {
 652         unsigned long flags;
 653         struct uart_8250_port *up =
 654                 container_of(port, struct uart_8250_port, port);
 655
 656         pm_runtime_get_sync(port->dev);
 657
 658         spin_lock_irqsave(&port->lock, flags);
 659         up->ier |= UART_IER_RLSI | UART_IER_RDI;
 660         serial_out(up, UART_IER, up->ier);
 661         spin_unlock_irqrestore(&port->lock, flags);
 662
 663         pm_runtime_mark_last_busy(port->dev);
 664         pm_runtime_put_autosuspend(port->dev);
 665 }
 666
 667 #ifdef CONFIG_SERIAL_8250_DMA
 668 static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir);
 669
 670 static void __dma_rx_do_complete(struct uart_8250_port *p, bool error)
 671 {
 672         struct uart_8250_dma    *dma = p->dma;
 673         struct tty_port         *tty_port = &p->port.state->port;
 674         struct dma_tx_state     state;
 675         int                     count;
 676
 677         dma_sync_single_for_cpu(dma->rxchan->device->dev, dma->rx_addr,
 678                                 dma->rx_size, DMA_FROM_DEVICE);
 679
 680         dma->rx_running = 0;
 681         dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
 682         dmaengine_terminate_all(dma->rxchan);
 683
 684         count = dma->rx_size - state.residue;
 685
 686         tty_insert_flip_string(tty_port, dma->rx_buf, count);
 687         p->port.icount.rx += count;
 688         if (!error)
 689                 omap_8250_rx_dma(p, 0);
 690
 691         tty_flip_buffer_push(tty_port);
 692 }
 693
 694 static void __dma_rx_complete(void *param)
 695 {
 696         __dma_rx_do_complete(param, false);
 697 }
 698
 699 static int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
 700 {
 701         struct uart_8250_dma            *dma = p->dma;
 702         struct dma_async_tx_descriptor  *desc;
 703
 704         switch (iir & 0x3f) {
 705         case UART_IIR_RLSI:
 706                 /* 8250_core handles errors and break interrupts */
 707                 if (dma->rx_running) {
 708                         dmaengine_pause(dma->rxchan);
 709                         __dma_rx_do_complete(p, true);
 710                 }
 711                 return -EIO;
 712         case UART_IIR_RX_TIMEOUT:
 713                 /*
 714                  * If RCVR FIFO trigger level was not reached, complete the
 715                  * transfer and let 8250_core copy the remaining data.
 716                  */
 717                 if (dma->rx_running) {
 718                         dmaengine_pause(dma->rxchan);
 719                         __dma_rx_do_complete(p, true);
 720                 }
 721                 return -ETIMEDOUT;
 722         case UART_IIR_RDI:
 723                 /*
 724                  * The OMAP UART is a special BEAST. If we receive RDI we _have_
 725                  * a DMA transfer programmed but it didn't work. One reason is
 726                  * that we were too slow and there were too many bytes in the
 727                  * FIFO, the UART counted wrong and never kicked the DMA engine
 728                  * to do anything. That means once we receive RDI on OMAP then
 729                  * the DMA won't do anything soon so we have to cancel the DMA
 730                  * transfer and purge the FIFO manually.
 731                  */
 732                 if (dma->rx_running) {
 733                         dmaengine_pause(dma->rxchan);
 734                         __dma_rx_do_complete(p, true);
 735                 }
 736                 return -ETIMEDOUT;
 737
 738         default:
 739                 break;
 740         }
 741
 742         if (dma->rx_running)
 743                 return 0;
 744
 745         desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
 746                                            dma->rx_size, DMA_DEV_TO_MEM,
 747                                            DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 748         if (!desc)
 749                 return -EBUSY;
 750
 751         dma->rx_running = 1;
 752         desc->callback = __dma_rx_complete;
 753         desc->callback_param = p;
 754
 755         dma->rx_cookie = dmaengine_submit(desc);
 756
 757         dma_sync_single_for_device(dma->rxchan->device->dev, dma->rx_addr,
 758                                    dma->rx_size, DMA_FROM_DEVICE);
 759
 760         dma_async_issue_pending(dma->rxchan);
 761         return 0;
 762 }
 763
 764 static int omap_8250_tx_dma(struct uart_8250_port *p);
 765
 766 static void omap_8250_dma_tx_complete(void *param)
 767 {
 768         struct uart_8250_port   *p = param;
 769         struct uart_8250_dma    *dma = p->dma;
 770         struct circ_buf         *xmit = &p->port.state->xmit;
 771         unsigned long           flags;
 772         bool                    en_thri = false;
 773         struct omap8250_priv    *priv = p->port.private_data;
 774
 775         dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
 776                                 UART_XMIT_SIZE, DMA_TO_DEVICE);
 777
 778         spin_lock_irqsave(&p->port.lock, flags);
 779
 780         dma->tx_running = 0;
 781
 782         xmit->tail += dma->tx_size;
 783         xmit->tail &= UART_XMIT_SIZE - 1;
 784         p->port.icount.tx += dma->tx_size;
 785
 786         if (priv->delayed_restore) {
 787                 priv->delayed_restore = 0;
 788                 omap8250_restore_regs(p);
 789         }
 790
 791         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 792                 uart_write_wakeup(&p->port);
 793
 794         if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
 795                 int ret;
 796
 797                 ret = omap_8250_tx_dma(p);
 798                 if (ret)
 799                         en_thri = true;
 800
 801         } else if (p->capabilities & UART_CAP_RPM) {
 802                 en_thri = true;
 803         }
 804
 805         if (en_thri) {
 806                 dma->tx_err = 1;
 807                 p->ier |= UART_IER_THRI;
 808                 serial_port_out(&p->port, UART_IER, p->ier);
 809         }
 810
 811         spin_unlock_irqrestore(&p->port.lock, flags);
 812 }
 813
 814 static int omap_8250_tx_dma(struct uart_8250_port *p)
 815 {
 816         struct uart_8250_dma            *dma = p->dma;
 817         struct omap8250_priv            *priv = p->port.private_data;
 818         struct circ_buf                 *xmit = &p->port.state->xmit;
 819         struct dma_async_tx_descriptor  *desc;
 820         unsigned int    skip_byte = 0;
 821         int ret;
 822
 823         if (dma->tx_running)
 824                 return 0;
 825         if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
 826
 827                 /*
 828                  * Even if no data, we need to return an error for the two cases
 829                  * below so serial8250_tx_chars() is invoked and properly clears
 830                  * THRI and/or runtime suspend.
 831                  */
 832                 if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
 833                         ret = -EBUSY;
 834                         goto err;
 835                 }
 836                 if (p->ier & UART_IER_THRI) {
 837                         p->ier &= ~UART_IER_THRI;
 838                         serial_out(p, UART_IER, p->ier);
 839                 }
 840                 return 0;
 841         }
 842
 843         dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
 844         if (priv->habit & OMAP_DMA_TX_KICK) {
 845                 u8 tx_lvl;
 846
 847                 /*
 848                  * We need to put the first byte into the FIFO in order to start
 849                  * the DMA transfer. For transfers smaller than four bytes we
 850                  * don't bother doing DMA at all. It seem not matter if there
 851                  * are still bytes in the FIFO from the last transfer (in case
 852                  * we got here directly from omap_8250_dma_tx_complete()). Bytes
 853                  * leaving the FIFO seem not to trigger the DMA transfer. It is
 854                  * really the byte that we put into the FIFO.
 855                  * If the FIFO is already full then we most likely got here from
 856                  * omap_8250_dma_tx_complete(). And this means the DMA engine
 857                  * just completed its work. We don't have to wait the complete
 858                  * 86us at 115200,8n1 but around 60us (not to mention lower
 859                  * baudrates). So in that case we take the interrupt and try
 860                  * again with an empty FIFO.
 861                  */
 862                 tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
 863                 if (tx_lvl == p->tx_loadsz) {
 864                         ret = -EBUSY;
 865                         goto err;
 866                 }
 867                 if (dma->tx_size < 4) {
 868                         ret = -EINVAL;
 869                         goto err;
 870                 }
 871                 skip_byte = 1;
 872         }
 873
 874         desc = dmaengine_prep_slave_single(dma->txchan,
 875                         dma->tx_addr + xmit->tail + skip_byte,
 876                         dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
 877                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 878         if (!desc) {
 879                 ret = -EBUSY;
 880                 goto err;
 881         }
 882
 883         dma->tx_running = 1;
 884
 885         desc->callback = omap_8250_dma_tx_complete;
 886         desc->callback_param = p;
 887
 888         dma->tx_cookie = dmaengine_submit(desc);
 889
 890         dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
 891                                    UART_XMIT_SIZE, DMA_TO_DEVICE);
 892
 893         dma_async_issue_pending(dma->txchan);
 894         if (dma->tx_err)
 895                 dma->tx_err = 0;
 896
 897         if (p->ier & UART_IER_THRI) {
 898                 p->ier &= ~UART_IER_THRI;
 899                 serial_out(p, UART_IER, p->ier);
 900         }
 901         if (skip_byte)
 902                 serial_out(p, UART_TX, xmit->buf[xmit->tail]);
 903         return 0;
 904 err:
 905         dma->tx_err = 1;
 906         return ret;
 907 }
 908
 909 /*
 910  * This is mostly serial8250_handle_irq(). We have a slightly different DMA
 911  * hoook for RX/TX and need different logic for them in the ISR. Therefore we
 912  * use the default routine in the non-DMA case and this one for with DMA.
 913  */
 914 static int omap_8250_dma_handle_irq(struct uart_port *port)
 915 {
 916         struct uart_8250_port *up = up_to_u8250p(port);
 917         unsigned char status;
 918         unsigned long flags;
 919         u8 iir;
 920         int dma_err = 0;
 921
 922         serial8250_rpm_get(up);
 923
 924         iir = serial_port_in(port, UART_IIR);
 925         if (iir & UART_IIR_NO_INT) {
 926                 serial8250_rpm_put(up);
 927                 return 0;
 928         }
 929
 930         spin_lock_irqsave(&port->lock, flags);
 931
 932         status = serial_port_in(port, UART_LSR);
 933
 934         if (status & (UART_LSR_DR | UART_LSR_BI)) {
 935
 936                 dma_err = omap_8250_rx_dma(up, iir);
 937                 if (dma_err) {
 938                         status = serial8250_rx_chars(up, status);
 939                         omap_8250_rx_dma(up, 0);
 940                 }
 941         }
 942         serial8250_modem_status(up);
 943         if (status & UART_LSR_THRE && up->dma->tx_err) {
 944                 if (uart_tx_stopped(&up->port) ||
 945                     uart_circ_empty(&up->port.state->xmit)) {
 946                         up->dma->tx_err = 0;
 947                         serial8250_tx_chars(up);
 948                 } else  {
 949                         /*
 950                          * try again due to an earlier failer which
 951                          * might have been resolved by now.
 952                          */
 953                         dma_err = omap_8250_tx_dma(up);
 954                         if (dma_err)
 955                                 serial8250_tx_chars(up);
 956                 }
 957         }
 958
 959         spin_unlock_irqrestore(&port->lock, flags);
 960         serial8250_rpm_put(up);
 961         return 1;
 962 }
 963
 964 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
 965 {
 966         return false;
 967 }
 968
 969 #else
 970
 971 static inline int omap_8250_rx_dma(struct uart_8250_port *p, unsigned int iir)
 972 {
 973         return -EINVAL;
 974 }
 975 #endif
 976
 977 static int omap8250_probe(struct platform_device *pdev)
 978 {
 979         struct resource *regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 980         struct resource *irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 981         struct omap8250_priv *priv;
 982         struct uart_8250_port up;
 983         int ret;
 984         void __iomem *membase;
 985
 986         if (!regs || !irq) {
 987                 dev_err(&pdev->dev, "missing registers or irq\n");
 988                 return -EINVAL;
 989         }
 990
 991         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
 992         if (!priv)
 993                 return -ENOMEM;
 994
 995         membase = devm_ioremap_nocache(&pdev->dev, regs->start,
 996                                        resource_size(regs));
 997         if (!membase)
 998                 return -ENODEV;
 999
1000         memset(&up, 0, sizeof(up));
1001         up.port.dev = &pdev->dev;
1002         up.port.mapbase = regs->start;
1003         up.port.membase = membase;
1004         up.port.irq = irq->start;
1005         /*
1006          * It claims to be 16C750 compatible however it is a little different.
1007          * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
1008          * have) is enabled via EFR instead of MCR. The type is set here 8250
1009          * just to get things going. UNKNOWN does not work for a few reasons and
1010          * we don't need our own type since we don't use 8250's set_termios()
1011          * or pm callback.
1012          */
1013         up.port.type = PORT_8250;
1014         up.port.iotype = UPIO_MEM;
1015         up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
1016                 UPF_HARD_FLOW;
1017         up.port.private_data = priv;
1018
1019         up.port.regshift = 2;
1020         up.port.fifosize = 64;
1021         up.tx_loadsz = 64;
1022         up.capabilities = UART_CAP_FIFO;
1023 #ifdef CONFIG_PM
1024         /*
1025          * Runtime PM is mostly transparent. However to do it right we need to a
1026          * TX empty interrupt before we can put the device to auto idle. So if
1027          * PM is not enabled we don't add that flag and can spare that one extra
1028          * interrupt in the TX path.
1029          */
1030         up.capabilities |= UART_CAP_RPM;
1031 #endif
1032         up.port.set_termios = omap_8250_set_termios;
1033         up.port.set_mctrl = omap8250_set_mctrl;
1034         up.port.pm = omap_8250_pm;
1035         up.port.startup = omap_8250_startup;
1036         up.port.shutdown = omap_8250_shutdown;
1037         up.port.throttle = omap_8250_throttle;
1038         up.port.unthrottle = omap_8250_unthrottle;
1039
1040         if (pdev->dev.of_node) {
1041                 ret = of_alias_get_id(pdev->dev.of_node, "serial");
1042
1043                 of_property_read_u32(pdev->dev.of_node, "clock-frequency",
1044                                      &up.port.uartclk);
1045                 priv->wakeirq = irq_of_parse_and_map(pdev->dev.of_node, 1);
1046         } else {
1047                 ret = pdev->id;
1048         }
1049         if (ret < 0) {
1050                 dev_err(&pdev->dev, "failed to get alias/pdev id\n");
1051                 return ret;
1052         }
1053         up.port.line = ret;
1054
1055         if (!up.port.uartclk) {
1056                 up.port.uartclk = DEFAULT_CLK_SPEED;
1057                 dev_warn(&pdev->dev,
1058                          "No clock speed specified: using default: %d\n",
1059                          DEFAULT_CLK_SPEED);
1060         }
1061
1062         priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1063         priv->calc_latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1064         pm_qos_add_request(&priv->pm_qos_request, PM_QOS_CPU_DMA_LATENCY,
1065                            priv->latency);
1066         INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
1067
1068         device_init_wakeup(&pdev->dev, true);
1069         pm_runtime_use_autosuspend(&pdev->dev);
1070         pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
1071
1072         pm_runtime_irq_safe(&pdev->dev);
1073         pm_runtime_enable(&pdev->dev);
1074
1075         pm_runtime_get_sync(&pdev->dev);
1076
1077         omap_serial_fill_features_erratas(&up, priv);
1078 #ifdef CONFIG_SERIAL_8250_DMA
1079         if (pdev->dev.of_node) {
1080                 /*
1081                  * Oh DMA support. If there are no DMA properties in the DT then
1082                  * we will fall back to a generic DMA channel which does not
1083                  * really work here. To ensure that we do not get a generic DMA
1084                  * channel assigned, we have the the_no_dma_filter_fn() here.
1085                  * To avoid "failed to request DMA" messages we check for DMA
1086                  * properties in DT.
1087                  */
1088                 ret = of_property_count_strings(pdev->dev.of_node, "dma-names");
1089                 if (ret == 2) {
1090                         up.dma = &priv->omap8250_dma;
1091                         up.port.handle_irq = omap_8250_dma_handle_irq;
1092                         priv->omap8250_dma.fn = the_no_dma_filter_fn;
1093                         priv->omap8250_dma.tx_dma = omap_8250_tx_dma;
1094                         priv->omap8250_dma.rx_dma = omap_8250_rx_dma;
1095                         priv->omap8250_dma.rx_size = RX_TRIGGER;
1096                         priv->omap8250_dma.rxconf.src_maxburst = RX_TRIGGER;
1097                         priv->omap8250_dma.txconf.dst_maxburst = TX_TRIGGER;
1098
1099                         if (of_machine_is_compatible("ti,am33xx"))
1100                                 priv->habit |= OMAP_DMA_TX_KICK;
1101                 }
1102         }
1103 #endif
1104         ret = serial8250_register_8250_port(&up);
1105         if (ret < 0) {
1106                 dev_err(&pdev->dev, "unable to register 8250 port\n");
1107                 goto err;
1108         }
1109         priv->line = ret;
1110         platform_set_drvdata(pdev, priv);
1111         pm_runtime_mark_last_busy(&pdev->dev);
1112         pm_runtime_put_autosuspend(&pdev->dev);
1113         return 0;
1114 err:
1115         pm_runtime_put(&pdev->dev);
1116         pm_runtime_disable(&pdev->dev);
1117         return ret;
1118 }
1119
1120 static int omap8250_remove(struct platform_device *pdev)
1121 {
1122         struct omap8250_priv *priv = platform_get_drvdata(pdev);
1123
1124         pm_runtime_put_sync(&pdev->dev);
1125         pm_runtime_disable(&pdev->dev);
1126         serial8250_unregister_port(priv->line);
1127         pm_qos_remove_request(&priv->pm_qos_request);
1128         device_init_wakeup(&pdev->dev, false);
1129         return 0;
1130 }
1131
1132 #ifdef CONFIG_PM
1133
1134 static inline void omap8250_enable_wakeirq(struct omap8250_priv *priv,
1135                                            bool enable)
1136 {
1137         if (!priv->wakeirq)
1138                 return;
1139
1140         if (enable)
1141                 enable_irq(priv->wakeirq);
1142         else
1143                 disable_irq_nosync(priv->wakeirq);
1144 }
1145
1146 static void omap8250_enable_wakeup(struct omap8250_priv *priv,
1147                                    bool enable)
1148 {
1149         if (enable == priv->wakeups_enabled)
1150                 return;
1151
1152         omap8250_enable_wakeirq(priv, enable);
1153         priv->wakeups_enabled = enable;
1154 }
1155 #endif
1156
1157 #ifdef CONFIG_PM_SLEEP
1158 static int omap8250_prepare(struct device *dev)
1159 {
1160         struct omap8250_priv *priv = dev_get_drvdata(dev);
1161
1162         if (!priv)
1163                 return 0;
1164         priv->is_suspending = true;
1165         return 0;
1166 }
1167
1168 static void omap8250_complete(struct device *dev)
1169 {
1170         struct omap8250_priv *priv = dev_get_drvdata(dev);
1171
1172         if (!priv)
1173                 return;
1174         priv->is_suspending = false;
1175 }
1176
1177 static int omap8250_suspend(struct device *dev)
1178 {
1179         struct omap8250_priv *priv = dev_get_drvdata(dev);
1180
1181         serial8250_suspend_port(priv->line);
1182         flush_work(&priv->qos_work);
1183
1184         if (device_may_wakeup(dev))
1185                 omap8250_enable_wakeup(priv, true);
1186         else
1187                 omap8250_enable_wakeup(priv, false);
1188         return 0;
1189 }
1190
1191 static int omap8250_resume(struct device *dev)
1192 {
1193         struct omap8250_priv *priv = dev_get_drvdata(dev);
1194
1195         if (device_may_wakeup(dev))
1196                 omap8250_enable_wakeup(priv, false);
1197
1198         serial8250_resume_port(priv->line);
1199         return 0;
1200 }
1201 #else
1202 #define omap8250_prepare NULL
1203 #define omap8250_complete NULL
1204 #endif
1205
1206 #ifdef CONFIG_PM
1207 static int omap8250_lost_context(struct uart_8250_port *up)
1208 {
1209         u32 val;
1210
1211         val = serial_in(up, UART_OMAP_MDR1);
1212         /*
1213          * If we lose context, then MDR1 is set to its reset value which is
1214          * UART_OMAP_MDR1_DISABLE. After set_termios() we set it either to 13x
1215          * or 16x but never to disable again.
1216          */
1217         if (val == UART_OMAP_MDR1_DISABLE)
1218                 return 1;
1219         return 0;
1220 }
1221
1222 static int omap8250_runtime_suspend(struct device *dev)
1223 {
1224         struct omap8250_priv *priv = dev_get_drvdata(dev);
1225         struct uart_8250_port *up;
1226
1227         up = serial8250_get_port(priv->line);
1228         /*
1229          * When using 'no_console_suspend', the console UART must not be
1230          * suspended. Since driver suspend is managed by runtime suspend,
1231          * preventing runtime suspend (by returning error) will keep device
1232          * active during suspend.
1233          */
1234         if (priv->is_suspending && !console_suspend_enabled) {
1235                 if (uart_console(&up->port))
1236                         return -EBUSY;
1237         }
1238
1239         omap8250_enable_wakeup(priv, true);
1240         if (up->dma)
1241                 omap_8250_rx_dma(up, UART_IIR_RX_TIMEOUT);
1242
1243         priv->latency = PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE;
1244         schedule_work(&priv->qos_work);
1245
1246         return 0;
1247 }
1248
1249 static int omap8250_runtime_resume(struct device *dev)
1250 {
1251         struct omap8250_priv *priv = dev_get_drvdata(dev);
1252         struct uart_8250_port *up;
1253         int loss_cntx;
1254
1255         /* In case runtime-pm tries this before we are setup */
1256         if (!priv)
1257                 return 0;
1258
1259         up = serial8250_get_port(priv->line);
1260         omap8250_enable_wakeup(priv, false);
1261         loss_cntx = omap8250_lost_context(up);
1262
1263         if (loss_cntx)
1264                 omap8250_restore_regs(up);
1265
1266         if (up->dma)
1267                 omap_8250_rx_dma(up, 0);
1268
1269         priv->latency = priv->calc_latency;
1270         schedule_work(&priv->qos_work);
1271         return 0;
1272 }
1273 #endif
1274
1275 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
1276 static int __init omap8250_console_fixup(void)
1277 {
1278         char *omap_str;
1279         char *options;
1280         u8 idx;
1281
1282         if (strstr(boot_command_line, "console=ttyS"))
1283                 /* user set a ttyS based name for the console */
1284                 return 0;
1285
1286         omap_str = strstr(boot_command_line, "console=ttyO");
1287         if (!omap_str)
1288                 /* user did not set ttyO based console, so we don't care */
1289                 return 0;
1290
1291         omap_str += 12;
1292         if ('0' <= *omap_str && *omap_str <= '9')
1293                 idx = *omap_str - '0';
1294         else
1295                 return 0;
1296
1297         omap_str++;
1298         if (omap_str[0] == ',') {
1299                 omap_str++;
1300                 options = omap_str;
1301         } else {
1302                 options = NULL;
1303         }
1304
1305         add_preferred_console("ttyS", idx, options);
1306         pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
1307                idx, idx);
1308         pr_err("This ensures that you still see kernel messages. Please\n");
1309         pr_err("update your kernel commandline.\n");
1310         return 0;
1311 }
1312 console_initcall(omap8250_console_fixup);
1313 #endif
1314
1315 static const struct dev_pm_ops omap8250_dev_pm_ops = {
1316         SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
1317         SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
1318                            omap8250_runtime_resume, NULL)
1319         .prepare        = omap8250_prepare,
1320         .complete       = omap8250_complete,
1321 };
1322
1323 static const struct of_device_id omap8250_dt_ids[] = {
1324         { .compatible = "ti,omap2-uart" },
1325         { .compatible = "ti,omap3-uart" },
1326         { .compatible = "ti,omap4-uart" },
1327         {},
1328 };
1329 MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
1330
1331 static struct platform_driver omap8250_platform_driver = {
1332         .driver = {
1333                 .name           = "omap8250",
1334                 .pm             = &omap8250_dev_pm_ops,
1335                 .of_match_table = omap8250_dt_ids,
1336         },
1337         .probe                  = omap8250_probe,
1338         .remove                 = omap8250_remove,
1339 };
1340 module_platform_driver(omap8250_platform_driver);
1341
1342 MODULE_AUTHOR("Sebastian Andrzej Siewior");
1343 MODULE_DESCRIPTION("OMAP 8250 Driver");
1344 MODULE_LICENSE("GPL v2");