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

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * 8250-core based driver for the OMAP internal UART
   4  *
   5  * based on omap-serial.c, Copyright (C) 2010 Texas Instruments.
   6  *
   7  * Copyright (C) 2014 Sebastian Andrzej Siewior
   8  *
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/device.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/serial_8250.h>
  16 #include <linux/serial_reg.h>
  17 #include <linux/tty_flip.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22 #include <linux/of_gpio.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/delay.h>
  25 #include <linux/pm_runtime.h>
  26 #include <linux/console.h>
  27 #include <linux/pm_qos.h>
  28 #include <linux/pm_wakeirq.h>
  29 #include <linux/dma-mapping.h>
  30 #include <linux/sys_soc.h>
  31
  32 #include "8250.h"
  33
  34 #define DEFAULT_CLK_SPEED       48000000
  35
  36 #define UART_ERRATA_i202_MDR1_ACCESS    (1 << 0)
  37 #define OMAP_UART_WER_HAS_TX_WAKEUP     (1 << 1)
  38 #define OMAP_DMA_TX_KICK                (1 << 2)
  39 /*
  40  * See Advisory 21 in AM437x errata SPRZ408B, updated April 2015.
  41  * The same errata is applicable to AM335x and DRA7x processors too.
  42  */
  43 #define UART_ERRATA_CLOCK_DISABLE       (1 << 3)
  44 #define UART_HAS_EFR2                   BIT(4)
  45 #define UART_HAS_RHR_IT_DIS             BIT(5)
  46 #define UART_RX_TIMEOUT_QUIRK           BIT(6)
  47
  48 #define OMAP_UART_FCR_RX_TRIG           6
  49 #define OMAP_UART_FCR_TX_TRIG           4
  50
  51 /* SCR register bitmasks */
  52 #define OMAP_UART_SCR_RX_TRIG_GRANU1_MASK       (1 << 7)
  53 #define OMAP_UART_SCR_TX_TRIG_GRANU1_MASK       (1 << 6)
  54 #define OMAP_UART_SCR_TX_EMPTY                  (1 << 3)
  55 #define OMAP_UART_SCR_DMAMODE_MASK              (3 << 1)
  56 #define OMAP_UART_SCR_DMAMODE_1                 (1 << 1)
  57 #define OMAP_UART_SCR_DMAMODE_CTL               (1 << 0)
  58
  59 /* MVR register bitmasks */
  60 #define OMAP_UART_MVR_SCHEME_SHIFT      30
  61 #define OMAP_UART_LEGACY_MVR_MAJ_MASK   0xf0
  62 #define OMAP_UART_LEGACY_MVR_MAJ_SHIFT  4
  63 #define OMAP_UART_LEGACY_MVR_MIN_MASK   0x0f
  64 #define OMAP_UART_MVR_MAJ_MASK          0x700
  65 #define OMAP_UART_MVR_MAJ_SHIFT         8
  66 #define OMAP_UART_MVR_MIN_MASK          0x3f
  67
  68 /* SYSC register bitmasks */
  69 #define OMAP_UART_SYSC_SOFTRESET        (1 << 1)
  70
  71 /* SYSS register bitmasks */
  72 #define OMAP_UART_SYSS_RESETDONE        (1 << 0)
  73
  74 #define UART_TI752_TLR_TX       0
  75 #define UART_TI752_TLR_RX       4
  76
  77 #define TRIGGER_TLR_MASK(x)     ((x & 0x3c) >> 2)
  78 #define TRIGGER_FCR_MASK(x)     (x & 3)
  79
  80 /* Enable XON/XOFF flow control on output */
  81 #define OMAP_UART_SW_TX         0x08
  82 /* Enable XON/XOFF flow control on input */
  83 #define OMAP_UART_SW_RX         0x02
  84
  85 #define OMAP_UART_WER_MOD_WKUP  0x7f
  86 #define OMAP_UART_TX_WAKEUP_EN  (1 << 7)
  87
  88 #define TX_TRIGGER      1
  89 #define RX_TRIGGER      48
  90
  91 #define OMAP_UART_TCR_RESTORE(x)        ((x / 4) << 4)
  92 #define OMAP_UART_TCR_HALT(x)           ((x / 4) << 0)
  93
  94 #define UART_BUILD_REVISION(x, y)       (((x) << 8) | (y))
  95
  96 #define OMAP_UART_REV_46 0x0406
  97 #define OMAP_UART_REV_52 0x0502
  98 #define OMAP_UART_REV_63 0x0603
  99
 100 /* Interrupt Enable Register 2 */
 101 #define UART_OMAP_IER2                  0x1B
 102 #define UART_OMAP_IER2_RHR_IT_DIS       BIT(2)
 103
 104 /* Enhanced features register 2 */
 105 #define UART_OMAP_EFR2                  0x23
 106 #define UART_OMAP_EFR2_TIMEOUT_BEHAVE   BIT(6)
 107
 108 /* RX FIFO occupancy indicator */
 109 #define UART_OMAP_RX_LVL                0x64
 110
 111 struct omap8250_priv {
 112         int line;
 113         u8 habit;
 114         u8 mdr1;
 115         u8 efr;
 116         u8 scr;
 117         u8 wer;
 118         u8 xon;
 119         u8 xoff;
 120         u8 delayed_restore;
 121         u16 quot;
 122
 123         u8 tx_trigger;
 124         u8 rx_trigger;
 125         bool is_suspending;
 126         int wakeirq;
 127         int wakeups_enabled;
 128         u32 latency;
 129         u32 calc_latency;
 130         struct pm_qos_request pm_qos_request;
 131         struct work_struct qos_work;
 132         struct uart_8250_dma omap8250_dma;
 133         spinlock_t rx_dma_lock;
 134         bool rx_dma_broken;
 135         bool throttled;
 136 };
 137
 138 struct omap8250_dma_params {
 139         u32 rx_size;
 140         u8 rx_trigger;
 141         u8 tx_trigger;
 142 };
 143
 144 struct omap8250_platdata {
 145         struct omap8250_dma_params *dma_params;
 146         u8 habit;
 147 };
 148
 149 #ifdef CONFIG_SERIAL_8250_DMA
 150 static void omap_8250_rx_dma_flush(struct uart_8250_port *p);
 151 #else
 152 static inline void omap_8250_rx_dma_flush(struct uart_8250_port *p) { }
 153 #endif
 154
 155 static u32 uart_read(struct uart_8250_port *up, u32 reg)
 156 {
 157         return readl(up->port.membase + (reg << up->port.regshift));
 158 }
 159
 160 static void omap8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
 161 {
 162         struct uart_8250_port *up = up_to_u8250p(port);
 163         struct omap8250_priv *priv = up->port.private_data;
 164         u8 lcr;
 165
 166         serial8250_do_set_mctrl(port, mctrl);
 167
 168         if (!mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS)) {
 169                 /*
 170                  * Turn off autoRTS if RTS is lowered and restore autoRTS
 171                  * setting if RTS is raised
 172                  */
 173                 lcr = serial_in(up, UART_LCR);
 174                 serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 175                 if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
 176                         priv->efr |= UART_EFR_RTS;
 177                 else
 178                         priv->efr &= ~UART_EFR_RTS;
 179                 serial_out(up, UART_EFR, priv->efr);
 180                 serial_out(up, UART_LCR, lcr);
 181         }
 182 }
 183
 184 /*
 185  * Work Around for Errata i202 (2430, 3430, 3630, 4430 and 4460)
 186  * The access to uart register after MDR1 Access
 187  * causes UART to corrupt data.
 188  *
 189  * Need a delay =
 190  * 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
 191  * give 10 times as much
 192  */
 193 static void omap_8250_mdr1_errataset(struct uart_8250_port *up,
 194                                      struct omap8250_priv *priv)
 195 {
 196         u8 timeout = 255;
 197
 198         serial_out(up, UART_OMAP_MDR1, priv->mdr1);
 199         udelay(2);
 200         serial_out(up, UART_FCR, up->fcr | UART_FCR_CLEAR_XMIT |
 201                         UART_FCR_CLEAR_RCVR);
 202         /*
 203          * Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
 204          * TX_FIFO_E bit is 1.
 205          */
 206         while (UART_LSR_THRE != (serial_in(up, UART_LSR) &
 207                                 (UART_LSR_THRE | UART_LSR_DR))) {
 208                 timeout--;
 209                 if (!timeout) {
 210                         /* Should *never* happen. we warn and carry on */
 211                         dev_crit(up->port.dev, "Errata i202: timedout %x\n",
 212                                  serial_in(up, UART_LSR));
 213                         break;
 214                 }
 215                 udelay(1);
 216         }
 217 }
 218
 219 static void omap_8250_get_divisor(struct uart_port *port, unsigned int baud,
 220                                   struct omap8250_priv *priv)
 221 {
 222         unsigned int uartclk = port->uartclk;
 223         unsigned int div_13, div_16;
 224         unsigned int abs_d13, abs_d16;
 225
 226         /*
 227          * Old custom speed handling.
 228          */
 229         if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST) {
 230                 priv->quot = port->custom_divisor & UART_DIV_MAX;
 231                 /*
 232                  * I assume that nobody is using this. But hey, if somebody
 233                  * would like to specify the divisor _and_ the mode then the
 234                  * driver is ready and waiting for it.
 235                  */
 236                 if (port->custom_divisor & (1 << 16))
 237                         priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
 238                 else
 239                         priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
 240                 return;
 241         }
 242         div_13 = DIV_ROUND_CLOSEST(uartclk, 13 * baud);
 243         div_16 = DIV_ROUND_CLOSEST(uartclk, 16 * baud);
 244
 245         if (!div_13)
 246                 div_13 = 1;
 247         if (!div_16)
 248                 div_16 = 1;
 249
 250         abs_d13 = abs(baud - uartclk / 13 / div_13);
 251         abs_d16 = abs(baud - uartclk / 16 / div_16);
 252
 253         if (abs_d13 >= abs_d16) {
 254                 priv->mdr1 = UART_OMAP_MDR1_16X_MODE;
 255                 priv->quot = div_16;
 256         } else {
 257                 priv->mdr1 = UART_OMAP_MDR1_13X_MODE;
 258                 priv->quot = div_13;
 259         }
 260 }
 261
 262 static void omap8250_update_scr(struct uart_8250_port *up,
 263                                 struct omap8250_priv *priv)
 264 {
 265         u8 old_scr;
 266
 267         old_scr = serial_in(up, UART_OMAP_SCR);
 268         if (old_scr == priv->scr)
 269                 return;
 270
 271         /*
 272          * The manual recommends not to enable the DMA mode selector in the SCR
 273          * (instead of the FCR) register _and_ selecting the DMA mode as one
 274          * register write because this may lead to malfunction.
 275          */
 276         if (priv->scr & OMAP_UART_SCR_DMAMODE_MASK)
 277                 serial_out(up, UART_OMAP_SCR,
 278                            priv->scr & ~OMAP_UART_SCR_DMAMODE_MASK);
 279         serial_out(up, UART_OMAP_SCR, priv->scr);
 280 }
 281
 282 static void omap8250_update_mdr1(struct uart_8250_port *up,
 283                                  struct omap8250_priv *priv)
 284 {
 285         if (priv->habit & UART_ERRATA_i202_MDR1_ACCESS)
 286                 omap_8250_mdr1_errataset(up, priv);
 287         else
 288                 serial_out(up, UART_OMAP_MDR1, priv->mdr1);
 289 }
 290
 291 static void omap8250_restore_regs(struct uart_8250_port *up)
 292 {
 293         struct omap8250_priv *priv = up->port.private_data;
 294         struct uart_8250_dma    *dma = up->dma;
 295
 296         if (dma && dma->tx_running) {
 297                 /*
 298                  * TCSANOW requests the change to occur immediately however if
 299                  * we have a TX-DMA operation in progress then it has been
 300                  * observed that it might stall and never complete. Therefore we
 301                  * delay DMA completes to prevent this hang from happen.
 302                  */
 303                 priv->delayed_restore = 1;
 304                 return;
 305         }
 306
 307         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 308         serial_out(up, UART_EFR, UART_EFR_ECB);
 309
 310         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
 311         serial8250_out_MCR(up, UART_MCR_TCRTLR);
 312         serial_out(up, UART_FCR, up->fcr);
 313
 314         omap8250_update_scr(up, priv);
 315
 316         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 317
 318         serial_out(up, UART_TI752_TCR, OMAP_UART_TCR_RESTORE(16) |
 319                         OMAP_UART_TCR_HALT(52));
 320         serial_out(up, UART_TI752_TLR,
 321                    TRIGGER_TLR_MASK(priv->tx_trigger) << UART_TI752_TLR_TX |
 322                    TRIGGER_TLR_MASK(priv->rx_trigger) << UART_TI752_TLR_RX);
 323
 324         serial_out(up, UART_LCR, 0);
 325
 326         /* drop TCR + TLR access, we setup XON/XOFF later */
 327         serial8250_out_MCR(up, up->mcr);
 328         serial_out(up, UART_IER, up->ier);
 329
 330         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 331         serial_dl_write(up, priv->quot);
 332
 333         serial_out(up, UART_EFR, priv->efr);
 334
 335         /* Configure flow control */
 336         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 337         serial_out(up, UART_XON1, priv->xon);
 338         serial_out(up, UART_XOFF1, priv->xoff);
 339
 340         serial_out(up, UART_LCR, up->lcr);
 341
 342         omap8250_update_mdr1(up, priv);
 343
 344         up->port.ops->set_mctrl(&up->port, up->port.mctrl);
 345 }
 346
 347 /*
 348  * OMAP can use "CLK / (16 or 13) / div" for baud rate. And then we have have
 349  * some differences in how we want to handle flow control.
 350  */
 351 static void omap_8250_set_termios(struct uart_port *port,
 352                                   struct ktermios *termios,
 353                                   struct ktermios *old)
 354 {
 355         struct uart_8250_port *up = up_to_u8250p(port);
 356         struct omap8250_priv *priv = up->port.private_data;
 357         unsigned char cval = 0;
 358         unsigned int baud;
 359
 360         switch (termios->c_cflag & CSIZE) {
 361         case CS5:
 362                 cval = UART_LCR_WLEN5;
 363                 break;
 364         case CS6:
 365                 cval = UART_LCR_WLEN6;
 366                 break;
 367         case CS7:
 368                 cval = UART_LCR_WLEN7;
 369                 break;
 370         default:
 371         case CS8:
 372                 cval = UART_LCR_WLEN8;
 373                 break;
 374         }
 375
 376         if (termios->c_cflag & CSTOPB)
 377                 cval |= UART_LCR_STOP;
 378         if (termios->c_cflag & PARENB)
 379                 cval |= UART_LCR_PARITY;
 380         if (!(termios->c_cflag & PARODD))
 381                 cval |= UART_LCR_EPAR;
 382         if (termios->c_cflag & CMSPAR)
 383                 cval |= UART_LCR_SPAR;
 384
 385         /*
 386          * Ask the core to calculate the divisor for us.
 387          */
 388         baud = uart_get_baud_rate(port, termios, old,
 389                                   port->uartclk / 16 / UART_DIV_MAX,
 390                                   port->uartclk / 13);
 391         omap_8250_get_divisor(port, baud, priv);
 392
 393         /*
 394          * Ok, we're now changing the port state. Do it with
 395          * interrupts disabled.
 396          */
 397         pm_runtime_get_sync(port->dev);
 398         spin_lock_irq(&port->lock);
 399
 400         /*
 401          * Update the per-port timeout.
 402          */
 403         uart_update_timeout(port, termios->c_cflag, baud);
 404
 405         up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
 406         if (termios->c_iflag & INPCK)
 407                 up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
 408         if (termios->c_iflag & (IGNBRK | PARMRK))
 409                 up->port.read_status_mask |= UART_LSR_BI;
 410
 411         /*
 412          * Characters to ignore
 413          */
 414         up->port.ignore_status_mask = 0;
 415         if (termios->c_iflag & IGNPAR)
 416                 up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
 417         if (termios->c_iflag & IGNBRK) {
 418                 up->port.ignore_status_mask |= UART_LSR_BI;
 419                 /*
 420                  * If we're ignoring parity and break indicators,
 421                  * ignore overruns too (for real raw support).
 422                  */
 423                 if (termios->c_iflag & IGNPAR)
 424                         up->port.ignore_status_mask |= UART_LSR_OE;
 425         }
 426
 427         /*
 428          * ignore all characters if CREAD is not set
 429          */
 430         if ((termios->c_cflag & CREAD) == 0)
 431                 up->port.ignore_status_mask |= UART_LSR_DR;
 432
 433         /*
 434          * Modem status interrupts
 435          */
 436         up->ier &= ~UART_IER_MSI;
 437         if (UART_ENABLE_MS(&up->port, termios->c_cflag))
 438                 up->ier |= UART_IER_MSI;
 439
 440         up->lcr = cval;
 441         /* Up to here it was mostly serial8250_do_set_termios() */
 442
 443         /*
 444          * We enable TRIG_GRANU for RX and TX and additionally we set
 445          * SCR_TX_EMPTY bit. The result is the following:
 446          * - RX_TRIGGER amount of bytes in the FIFO will cause an interrupt.
 447          * - less than RX_TRIGGER number of bytes will also cause an interrupt
 448          *   once the UART decides that there no new bytes arriving.
 449          * - Once THRE is enabled, the interrupt will be fired once the FIFO is
 450          *   empty - the trigger level is ignored here.
 451          *
 452          * Once DMA is enabled:
 453          * - UART will assert the TX DMA line once there is room for TX_TRIGGER
 454          *   bytes in the TX FIFO. On each assert the DMA engine will move
 455          *   TX_TRIGGER bytes into the FIFO.
 456          * - UART will assert the RX DMA line once there are RX_TRIGGER bytes in
 457          *   the FIFO and move RX_TRIGGER bytes.
 458          * This is because threshold and trigger values are the same.
 459          */
 460         up->fcr = UART_FCR_ENABLE_FIFO;
 461         up->fcr |= TRIGGER_FCR_MASK(priv->tx_trigger) << OMAP_UART_FCR_TX_TRIG;
 462         up->fcr |= TRIGGER_FCR_MASK(priv->rx_trigger) << OMAP_UART_FCR_RX_TRIG;
 463
 464         priv->scr = OMAP_UART_SCR_RX_TRIG_GRANU1_MASK | OMAP_UART_SCR_TX_EMPTY |
 465                 OMAP_UART_SCR_TX_TRIG_GRANU1_MASK;
 466
 467         if (up->dma)
 468                 priv->scr |= OMAP_UART_SCR_DMAMODE_1 |
 469                         OMAP_UART_SCR_DMAMODE_CTL;
 470
 471         priv->xon = termios->c_cc[VSTART];
 472         priv->xoff = termios->c_cc[VSTOP];
 473
 474         priv->efr = 0;
 475         up->port.status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS | UPSTAT_AUTOXOFF);
 476
 477         if (termios->c_cflag & CRTSCTS && up->port.flags & UPF_HARD_FLOW &&
 478             !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_RTS) &&
 479             !mctrl_gpio_to_gpiod(up->gpios, UART_GPIO_CTS)) {
 480                 /* Enable AUTOCTS (autoRTS is enabled when RTS is raised) */
 481                 up->port.status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
 482                 priv->efr |= UART_EFR_CTS;
 483         } else  if (up->port.flags & UPF_SOFT_FLOW) {
 484                 /*
 485                  * OMAP rx s/w flow control is borked; the transmitter remains
 486                  * stuck off even if rx flow control is subsequently disabled
 487                  */
 488
 489                 /*
 490                  * IXOFF Flag:
 491                  * Enable XON/XOFF flow control on output.
 492                  * Transmit XON1, XOFF1
 493                  */
 494                 if (termios->c_iflag & IXOFF) {
 495                         up->port.status |= UPSTAT_AUTOXOFF;
 496                         priv->efr |= OMAP_UART_SW_TX;
 497                 }
 498         }
 499         omap8250_restore_regs(up);
 500
 501         spin_unlock_irq(&up->port.lock);
 502         pm_runtime_mark_last_busy(port->dev);
 503         pm_runtime_put_autosuspend(port->dev);
 504
 505         /* calculate wakeup latency constraint */
 506         priv->calc_latency = USEC_PER_SEC * 64 * 8 / baud;
 507         priv->latency = priv->calc_latency;
 508
 509         schedule_work(&priv->qos_work);
 510
 511         /* Don't rewrite B0 */
 512         if (tty_termios_baud_rate(termios))
 513                 tty_termios_encode_baud_rate(termios, baud, baud);
 514 }
 515
 516 /* same as 8250 except that we may have extra flow bits set in EFR */
 517 static void omap_8250_pm(struct uart_port *port, unsigned int state,
 518                          unsigned int oldstate)
 519 {
 520         struct uart_8250_port *up = up_to_u8250p(port);
 521         u8 efr;
 522
 523         pm_runtime_get_sync(port->dev);
 524         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 525         efr = serial_in(up, UART_EFR);
 526         serial_out(up, UART_EFR, efr | UART_EFR_ECB);
 527         serial_out(up, UART_LCR, 0);
 528
 529         serial_out(up, UART_IER, (state != 0) ? UART_IERX_SLEEP : 0);
 530         serial_out(up, UART_LCR, UART_LCR_CONF_MODE_B);
 531         serial_out(up, UART_EFR, efr);
 532         serial_out(up, UART_LCR, 0);
 533
 534         pm_runtime_mark_last_busy(port->dev);
 535         pm_runtime_put_autosuspend(port->dev);
 536 }
 537
 538 static void omap_serial_fill_features_erratas(struct uart_8250_port *up,
 539                                               struct omap8250_priv *priv)
 540 {
 541         static const struct soc_device_attribute k3_soc_devices[] = {
 542                 { .family = "AM65X",  },
 543                 { .family = "J721E", .revision = "SR1.0" },
 544                 { /* sentinel */ }
 545         };
 546         u32 mvr, scheme;
 547         u16 revision, major, minor;
 548
 549         mvr = uart_read(up, UART_OMAP_MVER);
 550
 551         /* Check revision register scheme */
 552         scheme = mvr >> OMAP_UART_MVR_SCHEME_SHIFT;
 553
 554         switch (scheme) {
 555         case 0: /* Legacy Scheme: OMAP2/3 */
 556                 /* MINOR_REV[0:4], MAJOR_REV[4:7] */
 557                 major = (mvr & OMAP_UART_LEGACY_MVR_MAJ_MASK) >>
 558                         OMAP_UART_LEGACY_MVR_MAJ_SHIFT;
 559                 minor = (mvr & OMAP_UART_LEGACY_MVR_MIN_MASK);
 560                 break;
 561         case 1:
 562                 /* New Scheme: OMAP4+ */
 563                 /* MINOR_REV[0:5], MAJOR_REV[8:10] */
 564                 major = (mvr & OMAP_UART_MVR_MAJ_MASK) >>
 565                         OMAP_UART_MVR_MAJ_SHIFT;
 566                 minor = (mvr & OMAP_UART_MVR_MIN_MASK);
 567                 break;
 568         default:
 569                 dev_warn(up->port.dev,
 570                          "Unknown revision, defaulting to highest\n");
 571                 /* highest possible revision */
 572                 major = 0xff;
 573                 minor = 0xff;
 574         }
 575         /* normalize revision for the driver */
 576         revision = UART_BUILD_REVISION(major, minor);
 577
 578         switch (revision) {
 579         case OMAP_UART_REV_46:
 580                 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS;
 581                 break;
 582         case OMAP_UART_REV_52:
 583                 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
 584                                 OMAP_UART_WER_HAS_TX_WAKEUP;
 585                 break;
 586         case OMAP_UART_REV_63:
 587                 priv->habit |= UART_ERRATA_i202_MDR1_ACCESS |
 588                         OMAP_UART_WER_HAS_TX_WAKEUP;
 589                 break;
 590         default:
 591                 break;
 592         }
 593
 594         /*
 595          * AM65x SR1.0, AM65x SR2.0 and J721e SR1.0 don't
 596          * don't have RHR_IT_DIS bit in IER2 register. So drop to flag
 597          * to enable errata workaround.
 598          */
 599         if (soc_device_match(k3_soc_devices))
 600                 priv->habit &= ~UART_HAS_RHR_IT_DIS;
 601 }
 602
 603 static void omap8250_uart_qos_work(struct work_struct *work)
 604 {
 605         struct omap8250_priv *priv;
 606
 607         priv = container_of(work, struct omap8250_priv, qos_work);
 608         cpu_latency_qos_update_request(&priv->pm_qos_request, priv->latency);
 609 }
 610
 611 #ifdef CONFIG_SERIAL_8250_DMA
 612 static int omap_8250_dma_handle_irq(struct uart_port *port);
 613 #endif
 614
 615 static irqreturn_t omap8250_irq(int irq, void *dev_id)
 616 {
 617         struct uart_port *port = dev_id;
 618         struct omap8250_priv *priv = port->private_data;
 619         struct uart_8250_port *up = up_to_u8250p(port);
 620         unsigned int iir, lsr;
 621         int ret;
 622
 623 #ifdef CONFIG_SERIAL_8250_DMA
 624         if (up->dma) {
 625                 ret = omap_8250_dma_handle_irq(port);
 626                 return IRQ_RETVAL(ret);
 627         }
 628 #endif
 629
 630         serial8250_rpm_get(up);
 631         lsr = serial_port_in(port, UART_LSR);
 632         iir = serial_port_in(port, UART_IIR);
 633         ret = serial8250_handle_irq(port, iir);
 634
 635         /*
 636          * On K3 SoCs, it is observed that RX TIMEOUT is signalled after
 637          * FIFO has been drained, in which case a dummy read of RX FIFO
 638          * is required to clear RX TIMEOUT condition.
 639          */
 640         if (priv->habit & UART_RX_TIMEOUT_QUIRK &&
 641             (iir & UART_IIR_RX_TIMEOUT) == UART_IIR_RX_TIMEOUT &&
 642             serial_port_in(port, UART_OMAP_RX_LVL) == 0) {
 643                 serial_port_in(port, UART_RX);
 644         }
 645
 646         /* Stop processing interrupts on input overrun */
 647         if ((lsr & UART_LSR_OE) && up->overrun_backoff_time_ms > 0) {
 648                 unsigned long delay;
 649
 650                 up->ier = port->serial_in(port, UART_IER);
 651                 if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
 652                         port->ops->stop_rx(port);
 653                 } else {
 654                         /* Keep restarting the timer until
 655                          * the input overrun subsides.
 656                          */
 657                         cancel_delayed_work(&up->overrun_backoff);
 658                 }
 659
 660                 delay = msecs_to_jiffies(up->overrun_backoff_time_ms);
 661                 schedule_delayed_work(&up->overrun_backoff, delay);
 662         }
 663
 664         serial8250_rpm_put(up);
 665
 666         return IRQ_RETVAL(ret);
 667 }
 668
 669 static int omap_8250_startup(struct uart_port *port)
 670 {
 671         struct uart_8250_port *up = up_to_u8250p(port);
 672         struct omap8250_priv *priv = port->private_data;
 673         int ret;
 674
 675         if (priv->wakeirq) {
 676                 ret = dev_pm_set_dedicated_wake_irq(port->dev, priv->wakeirq);
 677                 if (ret)
 678                         return ret;
 679         }
 680
 681         pm_runtime_get_sync(port->dev);
 682
 683         up->mcr = 0;
 684         serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
 685
 686         serial_out(up, UART_LCR, UART_LCR_WLEN8);
 687
 688         up->lsr_saved_flags = 0;
 689         up->msr_saved_flags = 0;
 690
 691         /* Disable DMA for console UART */
 692         if (uart_console(port))
 693                 up->dma = NULL;
 694
 695         if (up->dma) {
 696                 ret = serial8250_request_dma(up);
 697                 if (ret) {
 698                         dev_warn_ratelimited(port->dev,
 699                                              "failed to request DMA\n");
 700                         up->dma = NULL;
 701                 }
 702         }
 703
 704         ret = request_irq(port->irq, omap8250_irq, IRQF_SHARED,
 705                           dev_name(port->dev), port);
 706         if (ret < 0)
 707                 goto err;
 708
 709         up->ier = UART_IER_RLSI | UART_IER_RDI;
 710         serial_out(up, UART_IER, up->ier);
 711
 712 #ifdef CONFIG_PM
 713         up->capabilities |= UART_CAP_RPM;
 714 #endif
 715
 716         /* Enable module level wake up */
 717         priv->wer = OMAP_UART_WER_MOD_WKUP;
 718         if (priv->habit & OMAP_UART_WER_HAS_TX_WAKEUP)
 719                 priv->wer |= OMAP_UART_TX_WAKEUP_EN;
 720         serial_out(up, UART_OMAP_WER, priv->wer);
 721
 722         if (up->dma && !(priv->habit & UART_HAS_EFR2))
 723                 up->dma->rx_dma(up);
 724
 725         pm_runtime_mark_last_busy(port->dev);
 726         pm_runtime_put_autosuspend(port->dev);
 727         return 0;
 728 err:
 729         pm_runtime_mark_last_busy(port->dev);
 730         pm_runtime_put_autosuspend(port->dev);
 731         dev_pm_clear_wake_irq(port->dev);
 732         return ret;
 733 }
 734
 735 static void omap_8250_shutdown(struct uart_port *port)
 736 {
 737         struct uart_8250_port *up = up_to_u8250p(port);
 738         struct omap8250_priv *priv = port->private_data;
 739
 740         flush_work(&priv->qos_work);
 741         if (up->dma)
 742                 omap_8250_rx_dma_flush(up);
 743
 744         pm_runtime_get_sync(port->dev);
 745
 746         serial_out(up, UART_OMAP_WER, 0);
 747         if (priv->habit & UART_HAS_EFR2)
 748                 serial_out(up, UART_OMAP_EFR2, 0x0);
 749
 750         up->ier = 0;
 751         serial_out(up, UART_IER, 0);
 752
 753         if (up->dma)
 754                 serial8250_release_dma(up);
 755
 756         /*
 757          * Disable break condition and FIFOs
 758          */
 759         if (up->lcr & UART_LCR_SBC)
 760                 serial_out(up, UART_LCR, up->lcr & ~UART_LCR_SBC);
 761         serial_out(up, UART_FCR, UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
 762
 763         pm_runtime_mark_last_busy(port->dev);
 764         pm_runtime_put_autosuspend(port->dev);
 765         free_irq(port->irq, port);
 766         dev_pm_clear_wake_irq(port->dev);
 767 }
 768
 769 static void omap_8250_throttle(struct uart_port *port)
 770 {
 771         struct omap8250_priv *priv = port->private_data;
 772         unsigned long flags;
 773
 774         pm_runtime_get_sync(port->dev);
 775
 776         spin_lock_irqsave(&port->lock, flags);
 777         port->ops->stop_rx(port);
 778         priv->throttled = true;
 779         spin_unlock_irqrestore(&port->lock, flags);
 780
 781         pm_runtime_mark_last_busy(port->dev);
 782         pm_runtime_put_autosuspend(port->dev);
 783 }
 784
 785 static void omap_8250_unthrottle(struct uart_port *port)
 786 {
 787         struct omap8250_priv *priv = port->private_data;
 788         struct uart_8250_port *up = up_to_u8250p(port);
 789         unsigned long flags;
 790
 791         pm_runtime_get_sync(port->dev);
 792
 793         spin_lock_irqsave(&port->lock, flags);
 794         priv->throttled = false;
 795         if (up->dma)
 796                 up->dma->rx_dma(up);
 797         up->ier |= UART_IER_RLSI | UART_IER_RDI;
 798         port->read_status_mask |= UART_LSR_DR;
 799         serial_out(up, UART_IER, up->ier);
 800         spin_unlock_irqrestore(&port->lock, flags);
 801
 802         pm_runtime_mark_last_busy(port->dev);
 803         pm_runtime_put_autosuspend(port->dev);
 804 }
 805
 806 #ifdef CONFIG_SERIAL_8250_DMA
 807 static int omap_8250_rx_dma(struct uart_8250_port *p);
 808
 809 /* Must be called while priv->rx_dma_lock is held */
 810 static void __dma_rx_do_complete(struct uart_8250_port *p)
 811 {
 812         struct uart_8250_dma    *dma = p->dma;
 813         struct tty_port         *tty_port = &p->port.state->port;
 814         struct omap8250_priv    *priv = p->port.private_data;
 815         struct dma_chan         *rxchan = dma->rxchan;
 816         dma_cookie_t            cookie;
 817         struct dma_tx_state     state;
 818         int                     count;
 819         int                     ret;
 820         u32                     reg;
 821
 822         if (!dma->rx_running)
 823                 goto out;
 824
 825         cookie = dma->rx_cookie;
 826         dma->rx_running = 0;
 827
 828         /* Re-enable RX FIFO interrupt now that transfer is complete */
 829         if (priv->habit & UART_HAS_RHR_IT_DIS) {
 830                 reg = serial_in(p, UART_OMAP_IER2);
 831                 reg &= ~UART_OMAP_IER2_RHR_IT_DIS;
 832                 serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS);
 833         }
 834
 835         dmaengine_tx_status(rxchan, cookie, &state);
 836
 837         count = dma->rx_size - state.residue + state.in_flight_bytes;
 838         if (count < dma->rx_size) {
 839                 dmaengine_terminate_async(rxchan);
 840
 841                 /*
 842                  * Poll for teardown to complete which guarantees in
 843                  * flight data is drained.
 844                  */
 845                 if (state.in_flight_bytes) {
 846                         int poll_count = 25;
 847
 848                         while (dmaengine_tx_status(rxchan, cookie, NULL) &&
 849                                poll_count--)
 850                                 cpu_relax();
 851
 852                         if (poll_count == -1)
 853                                 dev_err(p->port.dev, "teardown incomplete\n");
 854                 }
 855         }
 856         if (!count)
 857                 goto out;
 858         ret = tty_insert_flip_string(tty_port, dma->rx_buf, count);
 859
 860         p->port.icount.rx += ret;
 861         p->port.icount.buf_overrun += count - ret;
 862 out:
 863
 864         tty_flip_buffer_push(tty_port);
 865 }
 866
 867 static void __dma_rx_complete(void *param)
 868 {
 869         struct uart_8250_port *p = param;
 870         struct omap8250_priv *priv = p->port.private_data;
 871         struct uart_8250_dma *dma = p->dma;
 872         struct dma_tx_state     state;
 873         unsigned long flags;
 874
 875         spin_lock_irqsave(&p->port.lock, flags);
 876
 877         /*
 878          * If the tx status is not DMA_COMPLETE, then this is a delayed
 879          * completion callback. A previous RX timeout flush would have
 880          * already pushed the data, so exit.
 881          */
 882         if (dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state) !=
 883                         DMA_COMPLETE) {
 884                 spin_unlock_irqrestore(&p->port.lock, flags);
 885                 return;
 886         }
 887         __dma_rx_do_complete(p);
 888         if (!priv->throttled) {
 889                 p->ier |= UART_IER_RLSI | UART_IER_RDI;
 890                 serial_out(p, UART_IER, p->ier);
 891                 if (!(priv->habit & UART_HAS_EFR2))
 892                         omap_8250_rx_dma(p);
 893         }
 894
 895         spin_unlock_irqrestore(&p->port.lock, flags);
 896 }
 897
 898 static void omap_8250_rx_dma_flush(struct uart_8250_port *p)
 899 {
 900         struct omap8250_priv    *priv = p->port.private_data;
 901         struct uart_8250_dma    *dma = p->dma;
 902         struct dma_tx_state     state;
 903         unsigned long           flags;
 904         int ret;
 905
 906         spin_lock_irqsave(&priv->rx_dma_lock, flags);
 907
 908         if (!dma->rx_running) {
 909                 spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
 910                 return;
 911         }
 912
 913         ret = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, &state);
 914         if (ret == DMA_IN_PROGRESS) {
 915                 ret = dmaengine_pause(dma->rxchan);
 916                 if (WARN_ON_ONCE(ret))
 917                         priv->rx_dma_broken = true;
 918         }
 919         __dma_rx_do_complete(p);
 920         spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
 921 }
 922
 923 static int omap_8250_rx_dma(struct uart_8250_port *p)
 924 {
 925         struct omap8250_priv            *priv = p->port.private_data;
 926         struct uart_8250_dma            *dma = p->dma;
 927         int                             err = 0;
 928         struct dma_async_tx_descriptor  *desc;
 929         unsigned long                   flags;
 930         u32                             reg;
 931
 932         if (priv->rx_dma_broken)
 933                 return -EINVAL;
 934
 935         spin_lock_irqsave(&priv->rx_dma_lock, flags);
 936
 937         if (dma->rx_running) {
 938                 enum dma_status state;
 939
 940                 state = dmaengine_tx_status(dma->rxchan, dma->rx_cookie, NULL);
 941                 if (state == DMA_COMPLETE) {
 942                         /*
 943                          * Disable RX interrupts to allow RX DMA completion
 944                          * callback to run.
 945                          */
 946                         p->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
 947                         serial_out(p, UART_IER, p->ier);
 948                 }
 949                 goto out;
 950         }
 951
 952         desc = dmaengine_prep_slave_single(dma->rxchan, dma->rx_addr,
 953                                            dma->rx_size, DMA_DEV_TO_MEM,
 954                                            DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 955         if (!desc) {
 956                 err = -EBUSY;
 957                 goto out;
 958         }
 959
 960         dma->rx_running = 1;
 961         desc->callback = __dma_rx_complete;
 962         desc->callback_param = p;
 963
 964         dma->rx_cookie = dmaengine_submit(desc);
 965
 966         /*
 967          * Disable RX FIFO interrupt while RX DMA is enabled, else
 968          * spurious interrupt may be raised when data is in the RX FIFO
 969          * but is yet to be drained by DMA.
 970          */
 971         if (priv->habit & UART_HAS_RHR_IT_DIS) {
 972                 reg = serial_in(p, UART_OMAP_IER2);
 973                 reg |= UART_OMAP_IER2_RHR_IT_DIS;
 974                 serial_out(p, UART_OMAP_IER2, UART_OMAP_IER2_RHR_IT_DIS);
 975         }
 976
 977         dma_async_issue_pending(dma->rxchan);
 978 out:
 979         spin_unlock_irqrestore(&priv->rx_dma_lock, flags);
 980         return err;
 981 }
 982
 983 static int omap_8250_tx_dma(struct uart_8250_port *p);
 984
 985 static void omap_8250_dma_tx_complete(void *param)
 986 {
 987         struct uart_8250_port   *p = param;
 988         struct uart_8250_dma    *dma = p->dma;
 989         struct circ_buf         *xmit = &p->port.state->xmit;
 990         unsigned long           flags;
 991         bool                    en_thri = false;
 992         struct omap8250_priv    *priv = p->port.private_data;
 993
 994         dma_sync_single_for_cpu(dma->txchan->device->dev, dma->tx_addr,
 995                                 UART_XMIT_SIZE, DMA_TO_DEVICE);
 996
 997         spin_lock_irqsave(&p->port.lock, flags);
 998
 999         dma->tx_running = 0;
1000
1001         xmit->tail += dma->tx_size;
1002         xmit->tail &= UART_XMIT_SIZE - 1;
1003         p->port.icount.tx += dma->tx_size;
1004
1005         if (priv->delayed_restore) {
1006                 priv->delayed_restore = 0;
1007                 omap8250_restore_regs(p);
1008         }
1009
1010         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
1011                 uart_write_wakeup(&p->port);
1012
1013         if (!uart_circ_empty(xmit) && !uart_tx_stopped(&p->port)) {
1014                 int ret;
1015
1016                 ret = omap_8250_tx_dma(p);
1017                 if (ret)
1018                         en_thri = true;
1019         } else if (p->capabilities & UART_CAP_RPM) {
1020                 en_thri = true;
1021         }
1022
1023         if (en_thri) {
1024                 dma->tx_err = 1;
1025                 serial8250_set_THRI(p);
1026         }
1027
1028         spin_unlock_irqrestore(&p->port.lock, flags);
1029 }
1030
1031 static int omap_8250_tx_dma(struct uart_8250_port *p)
1032 {
1033         struct uart_8250_dma            *dma = p->dma;
1034         struct omap8250_priv            *priv = p->port.private_data;
1035         struct circ_buf                 *xmit = &p->port.state->xmit;
1036         struct dma_async_tx_descriptor  *desc;
1037         unsigned int    skip_byte = 0;
1038         int ret;
1039
1040         if (dma->tx_running)
1041                 return 0;
1042         if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
1043
1044                 /*
1045                  * Even if no data, we need to return an error for the two cases
1046                  * below so serial8250_tx_chars() is invoked and properly clears
1047                  * THRI and/or runtime suspend.
1048                  */
1049                 if (dma->tx_err || p->capabilities & UART_CAP_RPM) {
1050                         ret = -EBUSY;
1051                         goto err;
1052                 }
1053                 serial8250_clear_THRI(p);
1054                 return 0;
1055         }
1056
1057         dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
1058         if (priv->habit & OMAP_DMA_TX_KICK) {
1059                 u8 tx_lvl;
1060
1061                 /*
1062                  * We need to put the first byte into the FIFO in order to start
1063                  * the DMA transfer. For transfers smaller than four bytes we
1064                  * don't bother doing DMA at all. It seem not matter if there
1065                  * are still bytes in the FIFO from the last transfer (in case
1066                  * we got here directly from omap_8250_dma_tx_complete()). Bytes
1067                  * leaving the FIFO seem not to trigger the DMA transfer. It is
1068                  * really the byte that we put into the FIFO.
1069                  * If the FIFO is already full then we most likely got here from
1070                  * omap_8250_dma_tx_complete(). And this means the DMA engine
1071                  * just completed its work. We don't have to wait the complete
1072                  * 86us at 115200,8n1 but around 60us (not to mention lower
1073                  * baudrates). So in that case we take the interrupt and try
1074                  * again with an empty FIFO.
1075                  */
1076                 tx_lvl = serial_in(p, UART_OMAP_TX_LVL);
1077                 if (tx_lvl == p->tx_loadsz) {
1078                         ret = -EBUSY;
1079                         goto err;
1080                 }
1081                 if (dma->tx_size < 4) {
1082                         ret = -EINVAL;
1083                         goto err;
1084                 }
1085                 skip_byte = 1;
1086         }
1087
1088         desc = dmaengine_prep_slave_single(dma->txchan,
1089                         dma->tx_addr + xmit->tail + skip_byte,
1090                         dma->tx_size - skip_byte, DMA_MEM_TO_DEV,
1091                         DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
1092         if (!desc) {
1093                 ret = -EBUSY;
1094                 goto err;
1095         }
1096
1097         dma->tx_running = 1;
1098
1099         desc->callback = omap_8250_dma_tx_complete;
1100         desc->callback_param = p;
1101
1102         dma->tx_cookie = dmaengine_submit(desc);
1103
1104         dma_sync_single_for_device(dma->txchan->device->dev, dma->tx_addr,
1105                                    UART_XMIT_SIZE, DMA_TO_DEVICE);
1106
1107         dma_async_issue_pending(dma->txchan);
1108         if (dma->tx_err)
1109                 dma->tx_err = 0;
1110
1111         serial8250_clear_THRI(p);
1112         if (skip_byte)
1113                 serial_out(p, UART_TX, xmit->buf[xmit->tail]);
1114         return 0;
1115 err:
1116         dma->tx_err = 1;
1117         return ret;
1118 }
1119
1120 static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
1121 {
1122         switch (iir & 0x3f) {
1123         case UART_IIR_RLSI:
1124         case UART_IIR_RX_TIMEOUT:
1125         case UART_IIR_RDI:
1126                 omap_8250_rx_dma_flush(up);
1127                 return true;
1128         }
1129         return omap_8250_rx_dma(up);
1130 }
1131
1132 static unsigned char omap_8250_handle_rx_dma(struct uart_8250_port *up,
1133                                              u8 iir, unsigned char status)
1134 {
1135         if ((status & (UART_LSR_DR | UART_LSR_BI)) &&
1136             (iir & UART_IIR_RDI)) {
1137                 if (handle_rx_dma(up, iir)) {
1138                         status = serial8250_rx_chars(up, status);
1139                         omap_8250_rx_dma(up);
1140                 }
1141         }
1142
1143         return status;
1144 }
1145
1146 static void am654_8250_handle_rx_dma(struct uart_8250_port *up, u8 iir,
1147                                      unsigned char status)
1148 {
1149         /*
1150          * Queue a new transfer if FIFO has data.
1151          */
1152         if ((status & (UART_LSR_DR | UART_LSR_BI)) &&
1153             (up->ier & UART_IER_RDI)) {
1154                 omap_8250_rx_dma(up);
1155                 serial_out(up, UART_OMAP_EFR2, UART_OMAP_EFR2_TIMEOUT_BEHAVE);
1156         } else if ((iir & 0x3f) == UART_IIR_RX_TIMEOUT) {
1157                 /*
1158                  * Disable RX timeout, read IIR to clear
1159                  * current timeout condition, clear EFR2 to
1160                  * periodic timeouts, re-enable interrupts.
1161                  */
1162                 up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
1163                 serial_out(up, UART_IER, up->ier);
1164                 omap_8250_rx_dma_flush(up);
1165                 serial_in(up, UART_IIR);
1166                 serial_out(up, UART_OMAP_EFR2, 0x0);
1167                 up->ier |= UART_IER_RLSI | UART_IER_RDI;
1168                 serial_out(up, UART_IER, up->ier);
1169         }
1170 }
1171
1172 /*
1173  * This is mostly serial8250_handle_irq(). We have a slightly different DMA
1174  * hoook for RX/TX and need different logic for them in the ISR. Therefore we
1175  * use the default routine in the non-DMA case and this one for with DMA.
1176  */
1177 static int omap_8250_dma_handle_irq(struct uart_port *port)
1178 {
1179         struct uart_8250_port *up = up_to_u8250p(port);
1180         struct omap8250_priv *priv = up->port.private_data;
1181         unsigned char status;
1182         u8 iir;
1183
1184         serial8250_rpm_get(up);
1185
1186         iir = serial_port_in(port, UART_IIR);
1187         if (iir & UART_IIR_NO_INT) {
1188                 serial8250_rpm_put(up);
1189                 return IRQ_HANDLED;
1190         }
1191
1192         spin_lock(&port->lock);
1193
1194         status = serial_port_in(port, UART_LSR);
1195
1196         if (priv->habit & UART_HAS_EFR2)
1197                 am654_8250_handle_rx_dma(up, iir, status);
1198         else
1199                 status = omap_8250_handle_rx_dma(up, iir, status);
1200
1201         serial8250_modem_status(up);
1202         if (status & UART_LSR_THRE && up->dma->tx_err) {
1203                 if (uart_tx_stopped(&up->port) ||
1204                     uart_circ_empty(&up->port.state->xmit)) {
1205                         up->dma->tx_err = 0;
1206                         serial8250_tx_chars(up);
1207                 } else  {
1208                         /*
1209                          * try again due to an earlier failer which
1210                          * might have been resolved by now.
1211                          */
1212                         if (omap_8250_tx_dma(up))
1213                                 serial8250_tx_chars(up);
1214                 }
1215         }
1216
1217         uart_unlock_and_check_sysrq(port);
1218
1219         serial8250_rpm_put(up);
1220         return 1;
1221 }
1222
1223 static bool the_no_dma_filter_fn(struct dma_chan *chan, void *param)
1224 {
1225         return false;
1226 }
1227
1228 #else
1229
1230 static inline int omap_8250_rx_dma(struct uart_8250_port *p)
1231 {
1232         return -EINVAL;
1233 }
1234 #endif
1235
1236 static int omap8250_no_handle_irq(struct uart_port *port)
1237 {
1238         /* IRQ has not been requested but handling irq? */
1239         WARN_ONCE(1, "Unexpected irq handling before port startup\n");
1240         return 0;
1241 }
1242
1243 static struct omap8250_dma_params am654_dma = {
1244         .rx_size = SZ_2K,
1245         .rx_trigger = 1,
1246         .tx_trigger = TX_TRIGGER,
1247 };
1248
1249 static struct omap8250_dma_params am33xx_dma = {
1250         .rx_size = RX_TRIGGER,
1251         .rx_trigger = RX_TRIGGER,
1252         .tx_trigger = TX_TRIGGER,
1253 };
1254
1255 static struct omap8250_platdata am654_platdata = {
1256         .dma_params     = &am654_dma,
1257         .habit          = UART_HAS_EFR2 | UART_HAS_RHR_IT_DIS |
1258                           UART_RX_TIMEOUT_QUIRK,
1259 };
1260
1261 static struct omap8250_platdata am33xx_platdata = {
1262         .dma_params     = &am33xx_dma,
1263         .habit          = OMAP_DMA_TX_KICK | UART_ERRATA_CLOCK_DISABLE,
1264 };
1265
1266 static struct omap8250_platdata omap4_platdata = {
1267         .dma_params     = &am33xx_dma,
1268         .habit          = UART_ERRATA_CLOCK_DISABLE,
1269 };
1270
1271 static const struct of_device_id omap8250_dt_ids[] = {
1272         { .compatible = "ti,am654-uart", .data = &am654_platdata, },
1273         { .compatible = "ti,omap2-uart" },
1274         { .compatible = "ti,omap3-uart" },
1275         { .compatible = "ti,omap4-uart", .data = &omap4_platdata, },
1276         { .compatible = "ti,am3352-uart", .data = &am33xx_platdata, },
1277         { .compatible = "ti,am4372-uart", .data = &am33xx_platdata, },
1278         { .compatible = "ti,dra742-uart", .data = &omap4_platdata, },
1279         {},
1280 };
1281 MODULE_DEVICE_TABLE(of, omap8250_dt_ids);
1282
1283 static int omap8250_probe(struct platform_device *pdev)
1284 {
1285         struct device_node *np = pdev->dev.of_node;
1286         struct omap8250_priv *priv;
1287         const struct omap8250_platdata *pdata;
1288         struct uart_8250_port up;
1289         struct resource *regs;
1290         void __iomem *membase;
1291         int irq, ret;
1292
1293         irq = platform_get_irq(pdev, 0);
1294         if (irq < 0)
1295                 return irq;
1296
1297         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1298         if (!regs) {
1299                 dev_err(&pdev->dev, "missing registers\n");
1300                 return -EINVAL;
1301         }
1302
1303         priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
1304         if (!priv)
1305                 return -ENOMEM;
1306
1307         membase = devm_ioremap(&pdev->dev, regs->start,
1308                                        resource_size(regs));
1309         if (!membase)
1310                 return -ENODEV;
1311
1312         memset(&up, 0, sizeof(up));
1313         up.port.dev = &pdev->dev;
1314         up.port.mapbase = regs->start;
1315         up.port.membase = membase;
1316         up.port.irq = irq;
1317         /*
1318          * It claims to be 16C750 compatible however it is a little different.
1319          * It has EFR and has no FCR7_64byte bit. The AFE (which it claims to
1320          * have) is enabled via EFR instead of MCR. The type is set here 8250
1321          * just to get things going. UNKNOWN does not work for a few reasons and
1322          * we don't need our own type since we don't use 8250's set_termios()
1323          * or pm callback.
1324          */
1325         up.port.type = PORT_8250;
1326         up.port.iotype = UPIO_MEM;
1327         up.port.flags = UPF_FIXED_PORT | UPF_FIXED_TYPE | UPF_SOFT_FLOW |
1328                 UPF_HARD_FLOW;
1329         up.port.private_data = priv;
1330
1331         up.port.regshift = 2;
1332         up.port.fifosize = 64;
1333         up.tx_loadsz = 64;
1334         up.capabilities = UART_CAP_FIFO;
1335 #ifdef CONFIG_PM
1336         /*
1337          * Runtime PM is mostly transparent. However to do it right we need to a
1338          * TX empty interrupt before we can put the device to auto idle. So if
1339          * PM is not enabled we don't add that flag and can spare that one extra
1340          * interrupt in the TX path.
1341          */
1342         up.capabilities |= UART_CAP_RPM;
1343 #endif
1344         up.port.set_termios = omap_8250_set_termios;
1345         up.port.set_mctrl = omap8250_set_mctrl;
1346         up.port.pm = omap_8250_pm;
1347         up.port.startup = omap_8250_startup;
1348         up.port.shutdown = omap_8250_shutdown;
1349         up.port.throttle = omap_8250_throttle;
1350         up.port.unthrottle = omap_8250_unthrottle;
1351         up.port.rs485_config = serial8250_em485_config;
1352         up.rs485_start_tx = serial8250_em485_start_tx;
1353         up.rs485_stop_tx = serial8250_em485_stop_tx;
1354         up.port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_8250_CONSOLE);
1355
1356         ret = of_alias_get_id(np, "serial");
1357         if (ret < 0) {
1358                 dev_err(&pdev->dev, "failed to get alias\n");
1359                 return ret;
1360         }
1361         up.port.line = ret;
1362
1363         if (of_property_read_u32(np, "clock-frequency", &up.port.uartclk)) {
1364                 struct clk *clk;
1365
1366                 clk = devm_clk_get(&pdev->dev, NULL);
1367                 if (IS_ERR(clk)) {
1368                         if (PTR_ERR(clk) == -EPROBE_DEFER)
1369                                 return -EPROBE_DEFER;
1370                 } else {
1371                         up.port.uartclk = clk_get_rate(clk);
1372                 }
1373         }
1374
1375         if (of_property_read_u32(np, "overrun-throttle-ms",
1376                                  &up.overrun_backoff_time_ms) != 0)
1377                 up.overrun_backoff_time_ms = 0;
1378
1379         priv->wakeirq = irq_of_parse_and_map(np, 1);
1380
1381         pdata = of_device_get_match_data(&pdev->dev);
1382         if (pdata)
1383                 priv->habit |= pdata->habit;
1384
1385         if (!up.port.uartclk) {
1386                 up.port.uartclk = DEFAULT_CLK_SPEED;
1387                 dev_warn(&pdev->dev,
1388                          "No clock speed specified: using default: %d\n",
1389                          DEFAULT_CLK_SPEED);
1390         }
1391
1392         priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
1393         priv->calc_latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
1394         cpu_latency_qos_add_request(&priv->pm_qos_request, priv->latency);
1395         INIT_WORK(&priv->qos_work, omap8250_uart_qos_work);
1396
1397         spin_lock_init(&priv->rx_dma_lock);
1398
1399         device_init_wakeup(&pdev->dev, true);
1400         pm_runtime_enable(&pdev->dev);
1401         pm_runtime_use_autosuspend(&pdev->dev);
1402
1403         /*
1404          * Disable runtime PM until autosuspend delay unless specifically
1405          * enabled by the user via sysfs. This is the historic way to
1406          * prevent an unsafe default policy with lossy characters on wake-up.
1407          * For serdev devices this is not needed, the policy can be managed by
1408          * the serdev driver.
1409          */
1410         if (!of_get_available_child_count(pdev->dev.of_node))
1411                 pm_runtime_set_autosuspend_delay(&pdev->dev, -1);
1412
1413         pm_runtime_irq_safe(&pdev->dev);
1414
1415         pm_runtime_get_sync(&pdev->dev);
1416
1417         omap_serial_fill_features_erratas(&up, priv);
1418         up.port.handle_irq = omap8250_no_handle_irq;
1419         priv->rx_trigger = RX_TRIGGER;
1420         priv->tx_trigger = TX_TRIGGER;
1421 #ifdef CONFIG_SERIAL_8250_DMA
1422         /*
1423          * Oh DMA support. If there are no DMA properties in the DT then
1424          * we will fall back to a generic DMA channel which does not
1425          * really work here. To ensure that we do not get a generic DMA
1426          * channel assigned, we have the the_no_dma_filter_fn() here.
1427          * To avoid "failed to request DMA" messages we check for DMA
1428          * properties in DT.
1429          */
1430         ret = of_property_count_strings(np, "dma-names");
1431         if (ret == 2) {
1432                 struct omap8250_dma_params *dma_params = NULL;
1433
1434                 up.dma = &priv->omap8250_dma;
1435                 up.dma->fn = the_no_dma_filter_fn;
1436                 up.dma->tx_dma = omap_8250_tx_dma;
1437                 up.dma->rx_dma = omap_8250_rx_dma;
1438                 if (pdata)
1439                         dma_params = pdata->dma_params;
1440
1441                 if (dma_params) {
1442                         up.dma->rx_size = dma_params->rx_size;
1443                         up.dma->rxconf.src_maxburst = dma_params->rx_trigger;
1444                         up.dma->txconf.dst_maxburst = dma_params->tx_trigger;
1445                         priv->rx_trigger = dma_params->rx_trigger;
1446                         priv->tx_trigger = dma_params->tx_trigger;
1447                 } else {
1448                         up.dma->rx_size = RX_TRIGGER;
1449                         up.dma->rxconf.src_maxburst = RX_TRIGGER;
1450                         up.dma->txconf.dst_maxburst = TX_TRIGGER;
1451                 }
1452         }
1453 #endif
1454         ret = serial8250_register_8250_port(&up);
1455         if (ret < 0) {
1456                 dev_err(&pdev->dev, "unable to register 8250 port\n");
1457                 goto err;
1458         }
1459         priv->line = ret;
1460         platform_set_drvdata(pdev, priv);
1461         pm_runtime_mark_last_busy(&pdev->dev);
1462         pm_runtime_put_autosuspend(&pdev->dev);
1463         return 0;
1464 err:
1465         pm_runtime_dont_use_autosuspend(&pdev->dev);
1466         pm_runtime_put_sync(&pdev->dev);
1467         pm_runtime_disable(&pdev->dev);
1468         return ret;
1469 }
1470
1471 static int omap8250_remove(struct platform_device *pdev)
1472 {
1473         struct omap8250_priv *priv = platform_get_drvdata(pdev);
1474
1475         pm_runtime_dont_use_autosuspend(&pdev->dev);
1476         pm_runtime_put_sync(&pdev->dev);
1477         pm_runtime_disable(&pdev->dev);
1478         serial8250_unregister_port(priv->line);
1479         cpu_latency_qos_remove_request(&priv->pm_qos_request);
1480         device_init_wakeup(&pdev->dev, false);
1481         return 0;
1482 }
1483
1484 #ifdef CONFIG_PM_SLEEP
1485 static int omap8250_prepare(struct device *dev)
1486 {
1487         struct omap8250_priv *priv = dev_get_drvdata(dev);
1488
1489         if (!priv)
1490                 return 0;
1491         priv->is_suspending = true;
1492         return 0;
1493 }
1494
1495 static void omap8250_complete(struct device *dev)
1496 {
1497         struct omap8250_priv *priv = dev_get_drvdata(dev);
1498
1499         if (!priv)
1500                 return;
1501         priv->is_suspending = false;
1502 }
1503
1504 static int omap8250_suspend(struct device *dev)
1505 {
1506         struct omap8250_priv *priv = dev_get_drvdata(dev);
1507         struct uart_8250_port *up = serial8250_get_port(priv->line);
1508
1509         serial8250_suspend_port(priv->line);
1510
1511         pm_runtime_get_sync(dev);
1512         if (!device_may_wakeup(dev))
1513                 priv->wer = 0;
1514         serial_out(up, UART_OMAP_WER, priv->wer);
1515         pm_runtime_mark_last_busy(dev);
1516         pm_runtime_put_autosuspend(dev);
1517
1518         flush_work(&priv->qos_work);
1519         return 0;
1520 }
1521
1522 static int omap8250_resume(struct device *dev)
1523 {
1524         struct omap8250_priv *priv = dev_get_drvdata(dev);
1525
1526         serial8250_resume_port(priv->line);
1527         return 0;
1528 }
1529 #else
1530 #define omap8250_prepare NULL
1531 #define omap8250_complete NULL
1532 #endif
1533
1534 #ifdef CONFIG_PM
1535 static int omap8250_lost_context(struct uart_8250_port *up)
1536 {
1537         u32 val;
1538
1539         val = serial_in(up, UART_OMAP_SCR);
1540         /*
1541          * If we lose context, then SCR is set to its reset value of zero.
1542          * After set_termios() we set bit 3 of SCR (TX_EMPTY_CTL_IT) to 1,
1543          * among other bits, to never set the register back to zero again.
1544          */
1545         if (!val)
1546                 return 1;
1547         return 0;
1548 }
1549
1550 /* TODO: in future, this should happen via API in drivers/reset/ */
1551 static int omap8250_soft_reset(struct device *dev)
1552 {
1553         struct omap8250_priv *priv = dev_get_drvdata(dev);
1554         struct uart_8250_port *up = serial8250_get_port(priv->line);
1555         int timeout = 100;
1556         int sysc;
1557         int syss;
1558
1559         /*
1560          * At least on omap4, unused uarts may not idle after reset without
1561          * a basic scr dma configuration even with no dma in use. The
1562          * module clkctrl status bits will be 1 instead of 3 blocking idle
1563          * for the whole clockdomain. The softreset below will clear scr,
1564          * and we restore it on resume so this is safe to do on all SoCs
1565          * needing omap8250_soft_reset() quirk. Do it in two writes as
1566          * recommended in the comment for omap8250_update_scr().
1567          */
1568         serial_out(up, UART_OMAP_SCR, OMAP_UART_SCR_DMAMODE_1);
1569         serial_out(up, UART_OMAP_SCR,
1570                    OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL);
1571
1572         sysc = serial_in(up, UART_OMAP_SYSC);
1573
1574         /* softreset the UART */
1575         sysc |= OMAP_UART_SYSC_SOFTRESET;
1576         serial_out(up, UART_OMAP_SYSC, sysc);
1577
1578         /* By experiments, 1us enough for reset complete on AM335x */
1579         do {
1580                 udelay(1);
1581                 syss = serial_in(up, UART_OMAP_SYSS);
1582         } while (--timeout && !(syss & OMAP_UART_SYSS_RESETDONE));
1583
1584         if (!timeout) {
1585                 dev_err(dev, "timed out waiting for reset done\n");
1586                 return -ETIMEDOUT;
1587         }
1588
1589         return 0;
1590 }
1591
1592 static int omap8250_runtime_suspend(struct device *dev)
1593 {
1594         struct omap8250_priv *priv = dev_get_drvdata(dev);
1595         struct uart_8250_port *up;
1596
1597         /* In case runtime-pm tries this before we are setup */
1598         if (!priv)
1599                 return 0;
1600
1601         up = serial8250_get_port(priv->line);
1602         /*
1603          * When using 'no_console_suspend', the console UART must not be
1604          * suspended. Since driver suspend is managed by runtime suspend,
1605          * preventing runtime suspend (by returning error) will keep device
1606          * active during suspend.
1607          */
1608         if (priv->is_suspending && !console_suspend_enabled) {
1609                 if (uart_console(&up->port))
1610                         return -EBUSY;
1611         }
1612
1613         if (priv->habit & UART_ERRATA_CLOCK_DISABLE) {
1614                 int ret;
1615
1616                 ret = omap8250_soft_reset(dev);
1617                 if (ret)
1618                         return ret;
1619
1620                 /* Restore to UART mode after reset (for wakeup) */
1621                 omap8250_update_mdr1(up, priv);
1622                 /* Restore wakeup enable register */
1623                 serial_out(up, UART_OMAP_WER, priv->wer);
1624         }
1625
1626         if (up->dma && up->dma->rxchan)
1627                 omap_8250_rx_dma_flush(up);
1628
1629         priv->latency = PM_QOS_CPU_LATENCY_DEFAULT_VALUE;
1630         schedule_work(&priv->qos_work);
1631
1632         return 0;
1633 }
1634
1635 static int omap8250_runtime_resume(struct device *dev)
1636 {
1637         struct omap8250_priv *priv = dev_get_drvdata(dev);
1638         struct uart_8250_port *up;
1639
1640         /* In case runtime-pm tries this before we are setup */
1641         if (!priv)
1642                 return 0;
1643
1644         up = serial8250_get_port(priv->line);
1645
1646         if (omap8250_lost_context(up))
1647                 omap8250_restore_regs(up);
1648
1649         if (up->dma && up->dma->rxchan && !(priv->habit & UART_HAS_EFR2))
1650                 omap_8250_rx_dma(up);
1651
1652         priv->latency = priv->calc_latency;
1653         schedule_work(&priv->qos_work);
1654         return 0;
1655 }
1656 #endif
1657
1658 #ifdef CONFIG_SERIAL_8250_OMAP_TTYO_FIXUP
1659 static int __init omap8250_console_fixup(void)
1660 {
1661         char *omap_str;
1662         char *options;
1663         u8 idx;
1664
1665         if (strstr(boot_command_line, "console=ttyS"))
1666                 /* user set a ttyS based name for the console */
1667                 return 0;
1668
1669         omap_str = strstr(boot_command_line, "console=ttyO");
1670         if (!omap_str)
1671                 /* user did not set ttyO based console, so we don't care */
1672                 return 0;
1673
1674         omap_str += 12;
1675         if ('0' <= *omap_str && *omap_str <= '9')
1676                 idx = *omap_str - '0';
1677         else
1678                 return 0;
1679
1680         omap_str++;
1681         if (omap_str[0] == ',') {
1682                 omap_str++;
1683                 options = omap_str;
1684         } else {
1685                 options = NULL;
1686         }
1687
1688         add_preferred_console("ttyS", idx, options);
1689         pr_err("WARNING: Your 'console=ttyO%d' has been replaced by 'ttyS%d'\n",
1690                idx, idx);
1691         pr_err("This ensures that you still see kernel messages. Please\n");
1692         pr_err("update your kernel commandline.\n");
1693         return 0;
1694 }
1695 console_initcall(omap8250_console_fixup);
1696 #endif
1697
1698 static const struct dev_pm_ops omap8250_dev_pm_ops = {
1699         SET_SYSTEM_SLEEP_PM_OPS(omap8250_suspend, omap8250_resume)
1700         SET_RUNTIME_PM_OPS(omap8250_runtime_suspend,
1701                            omap8250_runtime_resume, NULL)
1702         .prepare        = omap8250_prepare,
1703         .complete       = omap8250_complete,
1704 };
1705
1706 static struct platform_driver omap8250_platform_driver = {
1707         .driver = {
1708                 .name           = "omap8250",
1709                 .pm             = &omap8250_dev_pm_ops,
1710                 .of_match_table = omap8250_dt_ids,
1711         },
1712         .probe                  = omap8250_probe,
1713         .remove                 = omap8250_remove,
1714 };
1715 module_platform_driver(omap8250_platform_driver);
1716
1717 MODULE_AUTHOR("Sebastian Andrzej Siewior");
1718 MODULE_DESCRIPTION("OMAP 8250 Driver");
1719 MODULE_LICENSE("GPL v2");