drivers/tty/serial/uartlite.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * uartlite.c: Serial driver for Xilinx uartlite serial controller
   4  *
   5  * Copyright (C) 2006 Peter Korsgaard <[email protected]>
   6  * Copyright (C) 2007 Secret Lab Technologies Ltd.
   7  */
   8
   9 #include <linux/platform_device.h>
  10 #include <linux/module.h>
  11 #include <linux/bitfield.h>
  12 #include <linux/console.h>
  13 #include <linux/serial.h>
  14 #include <linux/serial_core.h>
  15 #include <linux/tty.h>
  16 #include <linux/tty_flip.h>
  17 #include <linux/delay.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/init.h>
  20 #include <linux/io.h>
  21 #include <linux/iopoll.h>
  22 #include <linux/of.h>
  23 #include <linux/of_address.h>
  24 #include <linux/of_device.h>
  25 #include <linux/of_platform.h>
  26 #include <linux/clk.h>
  27 #include <linux/pm_runtime.h>
  28
  29 #define ULITE_NAME              "ttyUL"
  30 #define ULITE_MAJOR             204
  31 #define ULITE_MINOR             187
  32 #define ULITE_NR_UARTS          CONFIG_SERIAL_UARTLITE_NR_UARTS
  33
  34 /* ---------------------------------------------------------------------
  35  * Register definitions
  36  *
  37  * For register details see datasheet:
  38  * https://www.xilinx.com/support/documentation/ip_documentation/opb_uartlite.pdf
  39  */
  40
  41 #define ULITE_RX                0x00
  42 #define ULITE_TX                0x04
  43 #define ULITE_STATUS            0x08
  44 #define ULITE_CONTROL           0x0c
  45
  46 #define ULITE_REGION            16
  47
  48 #define ULITE_STATUS_RXVALID    0x01
  49 #define ULITE_STATUS_RXFULL     0x02
  50 #define ULITE_STATUS_TXEMPTY    0x04
  51 #define ULITE_STATUS_TXFULL     0x08
  52 #define ULITE_STATUS_IE         0x10
  53 #define ULITE_STATUS_OVERRUN    0x20
  54 #define ULITE_STATUS_FRAME      0x40
  55 #define ULITE_STATUS_PARITY     0x80
  56
  57 #define ULITE_CONTROL_RST_TX    0x01
  58 #define ULITE_CONTROL_RST_RX    0x02
  59 #define ULITE_CONTROL_IE        0x10
  60 #define UART_AUTOSUSPEND_TIMEOUT        3000    /* ms */
  61
  62 /* Static pointer to console port */
  63 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
  64 static struct uart_port *console_port;
  65 #endif
  66
  67 /**
  68  * struct uartlite_data: Driver private data
  69  * reg_ops: Functions to read/write registers
  70  * clk: Our parent clock, if present
  71  * baud: The baud rate configured when this device was synthesized
  72  * cflags: The cflags for parity and data bits
  73  */
  74 struct uartlite_data {
  75         const struct uartlite_reg_ops *reg_ops;
  76         struct clk *clk;
  77         unsigned int baud;
  78         tcflag_t cflags;
  79 };
  80
  81 struct uartlite_reg_ops {
  82         u32 (*in)(void __iomem *addr);
  83         void (*out)(u32 val, void __iomem *addr);
  84 };
  85
  86 static u32 uartlite_inbe32(void __iomem *addr)
  87 {
  88         return ioread32be(addr);
  89 }
  90
  91 static void uartlite_outbe32(u32 val, void __iomem *addr)
  92 {
  93         iowrite32be(val, addr);
  94 }
  95
  96 static const struct uartlite_reg_ops uartlite_be = {
  97         .in = uartlite_inbe32,
  98         .out = uartlite_outbe32,
  99 };
 100
 101 static u32 uartlite_inle32(void __iomem *addr)
 102 {
 103         return ioread32(addr);
 104 }
 105
 106 static void uartlite_outle32(u32 val, void __iomem *addr)
 107 {
 108         iowrite32(val, addr);
 109 }
 110
 111 static const struct uartlite_reg_ops uartlite_le = {
 112         .in = uartlite_inle32,
 113         .out = uartlite_outle32,
 114 };
 115
 116 static inline u32 uart_in32(u32 offset, struct uart_port *port)
 117 {
 118         struct uartlite_data *pdata = port->private_data;
 119
 120         return pdata->reg_ops->in(port->membase + offset);
 121 }
 122
 123 static inline void uart_out32(u32 val, u32 offset, struct uart_port *port)
 124 {
 125         struct uartlite_data *pdata = port->private_data;
 126
 127         pdata->reg_ops->out(val, port->membase + offset);
 128 }
 129
 130 static struct uart_port ulite_ports[ULITE_NR_UARTS];
 131
 132 static struct uart_driver ulite_uart_driver;
 133
 134 /* ---------------------------------------------------------------------
 135  * Core UART driver operations
 136  */
 137
 138 static int ulite_receive(struct uart_port *port, int stat)
 139 {
 140         struct tty_port *tport = &port->state->port;
 141         unsigned char ch = 0;
 142         char flag = TTY_NORMAL;
 143
 144         if ((stat & (ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
 145                      | ULITE_STATUS_FRAME)) == 0)
 146                 return 0;
 147
 148         /* stats */
 149         if (stat & ULITE_STATUS_RXVALID) {
 150                 port->icount.rx++;
 151                 ch = uart_in32(ULITE_RX, port);
 152
 153                 if (stat & ULITE_STATUS_PARITY)
 154                         port->icount.parity++;
 155         }
 156
 157         if (stat & ULITE_STATUS_OVERRUN)
 158                 port->icount.overrun++;
 159
 160         if (stat & ULITE_STATUS_FRAME)
 161                 port->icount.frame++;
 162
 163
 164         /* drop byte with parity error if IGNPAR specificed */
 165         if (stat & port->ignore_status_mask & ULITE_STATUS_PARITY)
 166                 stat &= ~ULITE_STATUS_RXVALID;
 167
 168         stat &= port->read_status_mask;
 169
 170         if (stat & ULITE_STATUS_PARITY)
 171                 flag = TTY_PARITY;
 172
 173
 174         stat &= ~port->ignore_status_mask;
 175
 176         if (stat & ULITE_STATUS_RXVALID)
 177                 tty_insert_flip_char(tport, ch, flag);
 178
 179         if (stat & ULITE_STATUS_FRAME)
 180                 tty_insert_flip_char(tport, 0, TTY_FRAME);
 181
 182         if (stat & ULITE_STATUS_OVERRUN)
 183                 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 184
 185         return 1;
 186 }
 187
 188 static int ulite_transmit(struct uart_port *port, int stat)
 189 {
 190         struct circ_buf *xmit  = &port->state->xmit;
 191
 192         if (stat & ULITE_STATUS_TXFULL)
 193                 return 0;
 194
 195         if (port->x_char) {
 196                 uart_out32(port->x_char, ULITE_TX, port);
 197                 port->x_char = 0;
 198                 port->icount.tx++;
 199                 return 1;
 200         }
 201
 202         if (uart_circ_empty(xmit) || uart_tx_stopped(port))
 203                 return 0;
 204
 205         uart_out32(xmit->buf[xmit->tail], ULITE_TX, port);
 206         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE-1);
 207         port->icount.tx++;
 208
 209         /* wake up */
 210         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 211                 uart_write_wakeup(port);
 212
 213         return 1;
 214 }
 215
 216 static irqreturn_t ulite_isr(int irq, void *dev_id)
 217 {
 218         struct uart_port *port = dev_id;
 219         int stat, busy, n = 0;
 220         unsigned long flags;
 221
 222         do {
 223                 spin_lock_irqsave(&port->lock, flags);
 224                 stat = uart_in32(ULITE_STATUS, port);
 225                 busy  = ulite_receive(port, stat);
 226                 busy |= ulite_transmit(port, stat);
 227                 spin_unlock_irqrestore(&port->lock, flags);
 228                 n++;
 229         } while (busy);
 230
 231         /* work done? */
 232         if (n > 1) {
 233                 tty_flip_buffer_push(&port->state->port);
 234                 return IRQ_HANDLED;
 235         } else {
 236                 return IRQ_NONE;
 237         }
 238 }
 239
 240 static unsigned int ulite_tx_empty(struct uart_port *port)
 241 {
 242         unsigned long flags;
 243         unsigned int ret;
 244
 245         spin_lock_irqsave(&port->lock, flags);
 246         ret = uart_in32(ULITE_STATUS, port);
 247         spin_unlock_irqrestore(&port->lock, flags);
 248
 249         return ret & ULITE_STATUS_TXEMPTY ? TIOCSER_TEMT : 0;
 250 }
 251
 252 static unsigned int ulite_get_mctrl(struct uart_port *port)
 253 {
 254         return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
 255 }
 256
 257 static void ulite_set_mctrl(struct uart_port *port, unsigned int mctrl)
 258 {
 259         /* N/A */
 260 }
 261
 262 static void ulite_stop_tx(struct uart_port *port)
 263 {
 264         /* N/A */
 265 }
 266
 267 static void ulite_start_tx(struct uart_port *port)
 268 {
 269         ulite_transmit(port, uart_in32(ULITE_STATUS, port));
 270 }
 271
 272 static void ulite_stop_rx(struct uart_port *port)
 273 {
 274         /* don't forward any more data (like !CREAD) */
 275         port->ignore_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 276                 | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 277 }
 278
 279 static void ulite_break_ctl(struct uart_port *port, int ctl)
 280 {
 281         /* N/A */
 282 }
 283
 284 static int ulite_startup(struct uart_port *port)
 285 {
 286         struct uartlite_data *pdata = port->private_data;
 287         int ret;
 288
 289         ret = clk_enable(pdata->clk);
 290         if (ret) {
 291                 dev_err(port->dev, "Failed to enable clock\n");
 292                 return ret;
 293         }
 294
 295         ret = request_irq(port->irq, ulite_isr, IRQF_SHARED | IRQF_TRIGGER_RISING,
 296                           "uartlite", port);
 297         if (ret)
 298                 return ret;
 299
 300         uart_out32(ULITE_CONTROL_RST_RX | ULITE_CONTROL_RST_TX,
 301                 ULITE_CONTROL, port);
 302         uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
 303
 304         return 0;
 305 }
 306
 307 static void ulite_shutdown(struct uart_port *port)
 308 {
 309         struct uartlite_data *pdata = port->private_data;
 310
 311         uart_out32(0, ULITE_CONTROL, port);
 312         uart_in32(ULITE_CONTROL, port); /* dummy */
 313         free_irq(port->irq, port);
 314         clk_disable(pdata->clk);
 315 }
 316
 317 static void ulite_set_termios(struct uart_port *port, struct ktermios *termios,
 318                               struct ktermios *old)
 319 {
 320         unsigned long flags;
 321         struct uartlite_data *pdata = port->private_data;
 322
 323         /* Set termios to what the hardware supports */
 324         termios->c_cflag &= ~(BRKINT | CSTOPB | PARENB | PARODD | CSIZE);
 325         termios->c_cflag |= pdata->cflags & (PARENB | PARODD | CSIZE);
 326         tty_termios_encode_baud_rate(termios, pdata->baud, pdata->baud);
 327
 328         spin_lock_irqsave(&port->lock, flags);
 329
 330         port->read_status_mask = ULITE_STATUS_RXVALID | ULITE_STATUS_OVERRUN
 331                 | ULITE_STATUS_TXFULL;
 332
 333         if (termios->c_iflag & INPCK)
 334                 port->read_status_mask |=
 335                         ULITE_STATUS_PARITY | ULITE_STATUS_FRAME;
 336
 337         port->ignore_status_mask = 0;
 338         if (termios->c_iflag & IGNPAR)
 339                 port->ignore_status_mask |= ULITE_STATUS_PARITY
 340                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 341
 342         /* ignore all characters if CREAD is not set */
 343         if ((termios->c_cflag & CREAD) == 0)
 344                 port->ignore_status_mask |=
 345                         ULITE_STATUS_RXVALID | ULITE_STATUS_PARITY
 346                         | ULITE_STATUS_FRAME | ULITE_STATUS_OVERRUN;
 347
 348         /* update timeout */
 349         uart_update_timeout(port, termios->c_cflag, pdata->baud);
 350
 351         spin_unlock_irqrestore(&port->lock, flags);
 352 }
 353
 354 static const char *ulite_type(struct uart_port *port)
 355 {
 356         return port->type == PORT_UARTLITE ? "uartlite" : NULL;
 357 }
 358
 359 static void ulite_release_port(struct uart_port *port)
 360 {
 361         release_mem_region(port->mapbase, ULITE_REGION);
 362         iounmap(port->membase);
 363         port->membase = NULL;
 364 }
 365
 366 static int ulite_request_port(struct uart_port *port)
 367 {
 368         struct uartlite_data *pdata = port->private_data;
 369         int ret;
 370
 371         pr_debug("ulite console: port=%p; port->mapbase=%llx\n",
 372                  port, (unsigned long long) port->mapbase);
 373
 374         if (!request_mem_region(port->mapbase, ULITE_REGION, "uartlite")) {
 375                 dev_err(port->dev, "Memory region busy\n");
 376                 return -EBUSY;
 377         }
 378
 379         port->membase = ioremap(port->mapbase, ULITE_REGION);
 380         if (!port->membase) {
 381                 dev_err(port->dev, "Unable to map registers\n");
 382                 release_mem_region(port->mapbase, ULITE_REGION);
 383                 return -EBUSY;
 384         }
 385
 386         pdata->reg_ops = &uartlite_be;
 387         ret = uart_in32(ULITE_CONTROL, port);
 388         uart_out32(ULITE_CONTROL_RST_TX, ULITE_CONTROL, port);
 389         ret = uart_in32(ULITE_STATUS, port);
 390         /* Endianess detection */
 391         if ((ret & ULITE_STATUS_TXEMPTY) != ULITE_STATUS_TXEMPTY)
 392                 pdata->reg_ops = &uartlite_le;
 393
 394         return 0;
 395 }
 396
 397 static void ulite_config_port(struct uart_port *port, int flags)
 398 {
 399         if (!ulite_request_port(port))
 400                 port->type = PORT_UARTLITE;
 401 }
 402
 403 static int ulite_verify_port(struct uart_port *port, struct serial_struct *ser)
 404 {
 405         /* we don't want the core code to modify any port params */
 406         return -EINVAL;
 407 }
 408
 409 static void ulite_pm(struct uart_port *port, unsigned int state,
 410                      unsigned int oldstate)
 411 {
 412         int ret;
 413
 414         if (!state) {
 415                 ret = pm_runtime_get_sync(port->dev);
 416                 if (ret < 0)
 417                         dev_err(port->dev, "Failed to enable clocks\n");
 418         } else {
 419                 pm_runtime_mark_last_busy(port->dev);
 420                 pm_runtime_put_autosuspend(port->dev);
 421         }
 422 }
 423
 424 #ifdef CONFIG_CONSOLE_POLL
 425 static int ulite_get_poll_char(struct uart_port *port)
 426 {
 427         if (!(uart_in32(ULITE_STATUS, port) & ULITE_STATUS_RXVALID))
 428                 return NO_POLL_CHAR;
 429
 430         return uart_in32(ULITE_RX, port);
 431 }
 432
 433 static void ulite_put_poll_char(struct uart_port *port, unsigned char ch)
 434 {
 435         while (uart_in32(ULITE_STATUS, port) & ULITE_STATUS_TXFULL)
 436                 cpu_relax();
 437
 438         /* write char to device */
 439         uart_out32(ch, ULITE_TX, port);
 440 }
 441 #endif
 442
 443 static const struct uart_ops ulite_ops = {
 444         .tx_empty       = ulite_tx_empty,
 445         .set_mctrl      = ulite_set_mctrl,
 446         .get_mctrl      = ulite_get_mctrl,
 447         .stop_tx        = ulite_stop_tx,
 448         .start_tx       = ulite_start_tx,
 449         .stop_rx        = ulite_stop_rx,
 450         .break_ctl      = ulite_break_ctl,
 451         .startup        = ulite_startup,
 452         .shutdown       = ulite_shutdown,
 453         .set_termios    = ulite_set_termios,
 454         .type           = ulite_type,
 455         .release_port   = ulite_release_port,
 456         .request_port   = ulite_request_port,
 457         .config_port    = ulite_config_port,
 458         .verify_port    = ulite_verify_port,
 459         .pm             = ulite_pm,
 460 #ifdef CONFIG_CONSOLE_POLL
 461         .poll_get_char  = ulite_get_poll_char,
 462         .poll_put_char  = ulite_put_poll_char,
 463 #endif
 464 };
 465
 466 /* ---------------------------------------------------------------------
 467  * Console driver operations
 468  */
 469
 470 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 471 static void ulite_console_wait_tx(struct uart_port *port)
 472 {
 473         u8 val;
 474
 475         /*
 476          * Spin waiting for TX fifo to have space available.
 477          * When using the Microblaze Debug Module this can take up to 1s
 478          */
 479         if (read_poll_timeout_atomic(uart_in32, val, !(val & ULITE_STATUS_TXFULL),
 480                                      0, 1000000, false, ULITE_STATUS, port))
 481                 dev_warn(port->dev,
 482                          "timeout waiting for TX buffer empty\n");
 483 }
 484
 485 static void ulite_console_putchar(struct uart_port *port, int ch)
 486 {
 487         ulite_console_wait_tx(port);
 488         uart_out32(ch, ULITE_TX, port);
 489 }
 490
 491 static void ulite_console_write(struct console *co, const char *s,
 492                                 unsigned int count)
 493 {
 494         struct uart_port *port = console_port;
 495         unsigned long flags;
 496         unsigned int ier;
 497         int locked = 1;
 498
 499         if (oops_in_progress) {
 500                 locked = spin_trylock_irqsave(&port->lock, flags);
 501         } else
 502                 spin_lock_irqsave(&port->lock, flags);
 503
 504         /* save and disable interrupt */
 505         ier = uart_in32(ULITE_STATUS, port) & ULITE_STATUS_IE;
 506         uart_out32(0, ULITE_CONTROL, port);
 507
 508         uart_console_write(port, s, count, ulite_console_putchar);
 509
 510         ulite_console_wait_tx(port);
 511
 512         /* restore interrupt state */
 513         if (ier)
 514                 uart_out32(ULITE_CONTROL_IE, ULITE_CONTROL, port);
 515
 516         if (locked)
 517                 spin_unlock_irqrestore(&port->lock, flags);
 518 }
 519
 520 static int ulite_console_setup(struct console *co, char *options)
 521 {
 522         struct uart_port *port = NULL;
 523         int baud = 9600;
 524         int bits = 8;
 525         int parity = 'n';
 526         int flow = 'n';
 527
 528         if (co->index >= 0 && co->index < ULITE_NR_UARTS)
 529                 port = ulite_ports + co->index;
 530
 531         /* Has the device been initialized yet? */
 532         if (!port || !port->mapbase) {
 533                 pr_debug("console on ttyUL%i not present\n", co->index);
 534                 return -ENODEV;
 535         }
 536
 537         console_port = port;
 538
 539         /* not initialized yet? */
 540         if (!port->membase) {
 541                 if (ulite_request_port(port))
 542                         return -ENODEV;
 543         }
 544
 545         if (options)
 546                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 547
 548         return uart_set_options(port, co, baud, parity, bits, flow);
 549 }
 550
 551 static struct console ulite_console = {
 552         .name   = ULITE_NAME,
 553         .write  = ulite_console_write,
 554         .device = uart_console_device,
 555         .setup  = ulite_console_setup,
 556         .flags  = CON_PRINTBUFFER,
 557         .index  = -1, /* Specified on the cmdline (e.g. console=ttyUL0 ) */
 558         .data   = &ulite_uart_driver,
 559 };
 560
 561 static void early_uartlite_putc(struct uart_port *port, int c)
 562 {
 563         /*
 564          * Limit how many times we'll spin waiting for TX FIFO status.
 565          * This will prevent lockups if the base address is incorrectly
 566          * set, or any other issue on the UARTLITE.
 567          * This limit is pretty arbitrary, unless we are at about 10 baud
 568          * we'll never timeout on a working UART.
 569          */
 570         unsigned retries = 1000000;
 571
 572         while (--retries &&
 573                (readl(port->membase + ULITE_STATUS) & ULITE_STATUS_TXFULL))
 574                 ;
 575
 576         /* Only attempt the iowrite if we didn't timeout */
 577         if (retries)
 578                 writel(c & 0xff, port->membase + ULITE_TX);
 579 }
 580
 581 static void early_uartlite_write(struct console *console,
 582                                  const char *s, unsigned n)
 583 {
 584         struct earlycon_device *device = console->data;
 585         uart_console_write(&device->port, s, n, early_uartlite_putc);
 586 }
 587
 588 static int __init early_uartlite_setup(struct earlycon_device *device,
 589                                        const char *options)
 590 {
 591         if (!device->port.membase)
 592                 return -ENODEV;
 593
 594         device->con->write = early_uartlite_write;
 595         return 0;
 596 }
 597 EARLYCON_DECLARE(uartlite, early_uartlite_setup);
 598 OF_EARLYCON_DECLARE(uartlite_b, "xlnx,opb-uartlite-1.00.b", early_uartlite_setup);
 599 OF_EARLYCON_DECLARE(uartlite_a, "xlnx,xps-uartlite-1.00.a", early_uartlite_setup);
 600
 601 #endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
 602
 603 static struct uart_driver ulite_uart_driver = {
 604         .owner          = THIS_MODULE,
 605         .driver_name    = "uartlite",
 606         .dev_name       = ULITE_NAME,
 607         .major          = ULITE_MAJOR,
 608         .minor          = ULITE_MINOR,
 609         .nr             = ULITE_NR_UARTS,
 610 #ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
 611         .cons           = &ulite_console,
 612 #endif
 613 };
 614
 615 /* ---------------------------------------------------------------------
 616  * Port assignment functions (mapping devices to uart_port structures)
 617  */
 618
 619 /** ulite_assign: register a uartlite device with the driver
 620  *
 621  * @dev: pointer to device structure
 622  * @id: requested id number.  Pass -1 for automatic port assignment
 623  * @base: base address of uartlite registers
 624  * @irq: irq number for uartlite
 625  * @pdata: private data for uartlite
 626  *
 627  * Returns: 0 on success, <0 otherwise
 628  */
 629 static int ulite_assign(struct device *dev, int id, phys_addr_t base, int irq,
 630                         struct uartlite_data *pdata)
 631 {
 632         struct uart_port *port;
 633         int rc;
 634
 635         /* if id = -1; then scan for a free id and use that */
 636         if (id < 0) {
 637                 for (id = 0; id < ULITE_NR_UARTS; id++)
 638                         if (ulite_ports[id].mapbase == 0)
 639                                 break;
 640         }
 641         if (id < 0 || id >= ULITE_NR_UARTS) {
 642                 dev_err(dev, "%s%i too large\n", ULITE_NAME, id);
 643                 return -EINVAL;
 644         }
 645
 646         if ((ulite_ports[id].mapbase) && (ulite_ports[id].mapbase != base)) {
 647                 dev_err(dev, "cannot assign to %s%i; it is already in use\n",
 648                         ULITE_NAME, id);
 649                 return -EBUSY;
 650         }
 651
 652         port = &ulite_ports[id];
 653
 654         spin_lock_init(&port->lock);
 655         port->fifosize = 16;
 656         port->regshift = 2;
 657         port->iotype = UPIO_MEM;
 658         port->iobase = 1; /* mark port in use */
 659         port->mapbase = base;
 660         port->membase = NULL;
 661         port->ops = &ulite_ops;
 662         port->irq = irq;
 663         port->flags = UPF_BOOT_AUTOCONF;
 664         port->dev = dev;
 665         port->type = PORT_UNKNOWN;
 666         port->line = id;
 667         port->private_data = pdata;
 668
 669         dev_set_drvdata(dev, port);
 670
 671         /* Register the port */
 672         rc = uart_add_one_port(&ulite_uart_driver, port);
 673         if (rc) {
 674                 dev_err(dev, "uart_add_one_port() failed; err=%i\n", rc);
 675                 port->mapbase = 0;
 676                 dev_set_drvdata(dev, NULL);
 677                 return rc;
 678         }
 679
 680         return 0;
 681 }
 682
 683 /** ulite_release: register a uartlite device with the driver
 684  *
 685  * @dev: pointer to device structure
 686  */
 687 static int ulite_release(struct device *dev)
 688 {
 689         struct uart_port *port = dev_get_drvdata(dev);
 690         int rc = 0;
 691
 692         if (port) {
 693                 rc = uart_remove_one_port(&ulite_uart_driver, port);
 694                 dev_set_drvdata(dev, NULL);
 695                 port->mapbase = 0;
 696         }
 697
 698         return rc;
 699 }
 700
 701 /**
 702  * ulite_suspend - Stop the device.
 703  *
 704  * @dev: handle to the device structure.
 705  * Return: 0 always.
 706  */
 707 static int __maybe_unused ulite_suspend(struct device *dev)
 708 {
 709         struct uart_port *port = dev_get_drvdata(dev);
 710
 711         if (port)
 712                 uart_suspend_port(&ulite_uart_driver, port);
 713
 714         return 0;
 715 }
 716
 717 /**
 718  * ulite_resume - Resume the device.
 719  *
 720  * @dev: handle to the device structure.
 721  * Return: 0 on success, errno otherwise.
 722  */
 723 static int __maybe_unused ulite_resume(struct device *dev)
 724 {
 725         struct uart_port *port = dev_get_drvdata(dev);
 726
 727         if (port)
 728                 uart_resume_port(&ulite_uart_driver, port);
 729
 730         return 0;
 731 }
 732
 733 static int __maybe_unused ulite_runtime_suspend(struct device *dev)
 734 {
 735         struct uart_port *port = dev_get_drvdata(dev);
 736         struct uartlite_data *pdata = port->private_data;
 737
 738         clk_disable(pdata->clk);
 739         return 0;
 740 };
 741
 742 static int __maybe_unused ulite_runtime_resume(struct device *dev)
 743 {
 744         struct uart_port *port = dev_get_drvdata(dev);
 745         struct uartlite_data *pdata = port->private_data;
 746         int ret;
 747
 748         ret = clk_enable(pdata->clk);
 749         if (ret) {
 750                 dev_err(dev, "Cannot enable clock.\n");
 751                 return ret;
 752         }
 753         return 0;
 754 }
 755
 756 /* ---------------------------------------------------------------------
 757  * Platform bus binding
 758  */
 759
 760 static const struct dev_pm_ops ulite_pm_ops = {
 761         SET_SYSTEM_SLEEP_PM_OPS(ulite_suspend, ulite_resume)
 762         SET_RUNTIME_PM_OPS(ulite_runtime_suspend,
 763                            ulite_runtime_resume, NULL)
 764 };
 765
 766 #if defined(CONFIG_OF)
 767 /* Match table for of_platform binding */
 768 static const struct of_device_id ulite_of_match[] = {
 769         { .compatible = "xlnx,opb-uartlite-1.00.b", },
 770         { .compatible = "xlnx,xps-uartlite-1.00.a", },
 771         {}
 772 };
 773 MODULE_DEVICE_TABLE(of, ulite_of_match);
 774 #endif /* CONFIG_OF */
 775
 776 static int ulite_probe(struct platform_device *pdev)
 777 {
 778         struct resource *res;
 779         struct uartlite_data *pdata;
 780         int irq, ret;
 781         int id = pdev->id;
 782
 783         pdata = devm_kzalloc(&pdev->dev, sizeof(struct uartlite_data),
 784                              GFP_KERNEL);
 785         if (!pdata)
 786                 return -ENOMEM;
 787
 788         if (IS_ENABLED(CONFIG_OF)) {
 789                 const char *prop;
 790                 struct device_node *np = pdev->dev.of_node;
 791                 u32 val = 0;
 792
 793                 prop = "port-number";
 794                 ret = of_property_read_u32(np, prop, &id);
 795                 if (ret && ret != -EINVAL)
 796 of_err:
 797                         return dev_err_probe(&pdev->dev, ret,
 798                                              "could not read %s\n", prop);
 799
 800                 prop = "current-speed";
 801                 ret = of_property_read_u32(np, prop, &pdata->baud);
 802                 if (ret)
 803                         goto of_err;
 804
 805                 prop = "xlnx,use-parity";
 806                 ret = of_property_read_u32(np, prop, &val);
 807                 if (ret && ret != -EINVAL)
 808                         goto of_err;
 809
 810                 if (val) {
 811                         prop = "xlnx,odd-parity";
 812                         ret = of_property_read_u32(np, prop, &val);
 813                         if (ret)
 814                                 goto of_err;
 815
 816                         if (val)
 817                                 pdata->cflags |= PARODD;
 818                         pdata->cflags |= PARENB;
 819                 }
 820
 821                 val = 8;
 822                 prop = "xlnx,data-bits";
 823                 ret = of_property_read_u32(np, prop, &val);
 824                 if (ret && ret != -EINVAL)
 825                         goto of_err;
 826
 827                 switch (val) {
 828                 case 5:
 829                         pdata->cflags |= CS5;
 830                         break;
 831                 case 6:
 832                         pdata->cflags |= CS6;
 833                         break;
 834                 case 7:
 835                         pdata->cflags |= CS7;
 836                         break;
 837                 case 8:
 838                         pdata->cflags |= CS8;
 839                         break;
 840                 default:
 841                         return dev_err_probe(&pdev->dev, -EINVAL,
 842                                              "bad data bits %d\n", val);
 843                 }
 844         } else {
 845                 pdata->baud = 9600;
 846                 pdata->cflags = CS8;
 847         }
 848
 849         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 850         if (!res)
 851                 return -ENODEV;
 852
 853         irq = platform_get_irq(pdev, 0);
 854         if (irq < 0)
 855                 return irq;
 856
 857         pdata->clk = devm_clk_get(&pdev->dev, "s_axi_aclk");
 858         if (IS_ERR(pdata->clk)) {
 859                 if (PTR_ERR(pdata->clk) != -ENOENT)
 860                         return PTR_ERR(pdata->clk);
 861
 862                 /*
 863                  * Clock framework support is optional, continue on
 864                  * anyways if we don't find a matching clock.
 865                  */
 866                 pdata->clk = NULL;
 867         }
 868
 869         ret = clk_prepare_enable(pdata->clk);
 870         if (ret) {
 871                 dev_err(&pdev->dev, "Failed to prepare clock\n");
 872                 return ret;
 873         }
 874
 875         pm_runtime_use_autosuspend(&pdev->dev);
 876         pm_runtime_set_autosuspend_delay(&pdev->dev, UART_AUTOSUSPEND_TIMEOUT);
 877         pm_runtime_set_active(&pdev->dev);
 878         pm_runtime_enable(&pdev->dev);
 879
 880         if (!ulite_uart_driver.state) {
 881                 dev_dbg(&pdev->dev, "uartlite: calling uart_register_driver()\n");
 882                 ret = uart_register_driver(&ulite_uart_driver);
 883                 if (ret < 0) {
 884                         dev_err(&pdev->dev, "Failed to register driver\n");
 885                         clk_disable_unprepare(pdata->clk);
 886                         return ret;
 887                 }
 888         }
 889
 890         ret = ulite_assign(&pdev->dev, id, res->start, irq, pdata);
 891
 892         pm_runtime_mark_last_busy(&pdev->dev);
 893         pm_runtime_put_autosuspend(&pdev->dev);
 894
 895         return ret;
 896 }
 897
 898 static int ulite_remove(struct platform_device *pdev)
 899 {
 900         struct uart_port *port = dev_get_drvdata(&pdev->dev);
 901         struct uartlite_data *pdata = port->private_data;
 902         int rc;
 903
 904         clk_disable_unprepare(pdata->clk);
 905         rc = ulite_release(&pdev->dev);
 906         pm_runtime_disable(&pdev->dev);
 907         pm_runtime_set_suspended(&pdev->dev);
 908         pm_runtime_dont_use_autosuspend(&pdev->dev);
 909         return rc;
 910 }
 911
 912 /* work with hotplug and coldplug */
 913 MODULE_ALIAS("platform:uartlite");
 914
 915 static struct platform_driver ulite_platform_driver = {
 916         .probe = ulite_probe,
 917         .remove = ulite_remove,
 918         .driver = {
 919                 .name  = "uartlite",
 920                 .of_match_table = of_match_ptr(ulite_of_match),
 921                 .pm = &ulite_pm_ops,
 922         },
 923 };
 924
 925 /* ---------------------------------------------------------------------
 926  * Module setup/teardown
 927  */
 928
 929 static int __init ulite_init(void)
 930 {
 931
 932         pr_debug("uartlite: calling platform_driver_register()\n");
 933         return platform_driver_register(&ulite_platform_driver);
 934 }
 935
 936 static void __exit ulite_exit(void)
 937 {
 938         platform_driver_unregister(&ulite_platform_driver);
 939         if (ulite_uart_driver.state)
 940                 uart_unregister_driver(&ulite_uart_driver);
 941 }
 942
 943 module_init(ulite_init);
 944 module_exit(ulite_exit);
 945
 946 MODULE_AUTHOR("Peter Korsgaard <[email protected]>");
 947 MODULE_DESCRIPTION("Xilinx uartlite serial driver");
 948 MODULE_LICENSE("GPL");