drivers/tty/serial/sprd_serial.c

   1 /*
   2  * Copyright (C) 2012-2015 Spreadtrum Communications Inc.
   3  *
   4  * This software is licensed under the terms of the GNU General Public
   5  * License version 2, as published by the Free Software Foundation, and
   6  * may be copied, distributed, and modified under those terms.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #if defined(CONFIG_SERIAL_SPRD_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
  15 #define SUPPORT_SYSRQ
  16 #endif
  17
  18 #include <linux/clk.h>
  19 #include <linux/console.h>
  20 #include <linux/delay.h>
  21 #include <linux/io.h>
  22 #include <linux/ioport.h>
  23 #include <linux/kernel.h>
  24 #include <linux/module.h>
  25 #include <linux/of.h>
  26 #include <linux/platform_device.h>
  27 #include <linux/serial_core.h>
  28 #include <linux/serial.h>
  29 #include <linux/slab.h>
  30 #include <linux/tty.h>
  31 #include <linux/tty_flip.h>
  32
  33 /* device name */
  34 #define UART_NR_MAX             8
  35 #define SPRD_TTY_NAME           "ttyS"
  36 #define SPRD_FIFO_SIZE          128
  37 #define SPRD_DEF_RATE           26000000
  38 #define SPRD_BAUD_IO_LIMIT      3000000
  39 #define SPRD_TIMEOUT            256
  40
  41 /* the offset of serial registers and BITs for them */
  42 /* data registers */
  43 #define SPRD_TXD                0x0000
  44 #define SPRD_RXD                0x0004
  45
  46 /* line status register and its BITs  */
  47 #define SPRD_LSR                0x0008
  48 #define SPRD_LSR_OE             BIT(4)
  49 #define SPRD_LSR_FE             BIT(3)
  50 #define SPRD_LSR_PE             BIT(2)
  51 #define SPRD_LSR_BI             BIT(7)
  52 #define SPRD_LSR_TX_OVER        BIT(15)
  53
  54 /* data number in TX and RX fifo */
  55 #define SPRD_STS1               0x000C
  56
  57 /* interrupt enable register and its BITs */
  58 #define SPRD_IEN                0x0010
  59 #define SPRD_IEN_RX_FULL        BIT(0)
  60 #define SPRD_IEN_TX_EMPTY       BIT(1)
  61 #define SPRD_IEN_BREAK_DETECT   BIT(7)
  62 #define SPRD_IEN_TIMEOUT        BIT(13)
  63
  64 /* interrupt clear register */
  65 #define SPRD_ICLR               0x0014
  66
  67 /* line control register */
  68 #define SPRD_LCR                0x0018
  69 #define SPRD_LCR_STOP_1BIT      0x10
  70 #define SPRD_LCR_STOP_2BIT      0x30
  71 #define SPRD_LCR_DATA_LEN       (BIT(2) | BIT(3))
  72 #define SPRD_LCR_DATA_LEN5      0x0
  73 #define SPRD_LCR_DATA_LEN6      0x4
  74 #define SPRD_LCR_DATA_LEN7      0x8
  75 #define SPRD_LCR_DATA_LEN8      0xc
  76 #define SPRD_LCR_PARITY (BIT(0) | BIT(1))
  77 #define SPRD_LCR_PARITY_EN      0x2
  78 #define SPRD_LCR_EVEN_PAR       0x0
  79 #define SPRD_LCR_ODD_PAR        0x1
  80
  81 /* control register 1 */
  82 #define SPRD_CTL1                       0x001C
  83 #define RX_HW_FLOW_CTL_THLD     BIT(6)
  84 #define RX_HW_FLOW_CTL_EN       BIT(7)
  85 #define TX_HW_FLOW_CTL_EN       BIT(8)
  86 #define RX_TOUT_THLD_DEF        0x3E00
  87 #define RX_HFC_THLD_DEF 0x40
  88
  89 /* fifo threshold register */
  90 #define SPRD_CTL2               0x0020
  91 #define THLD_TX_EMPTY   0x40
  92 #define THLD_RX_FULL    0x40
  93
  94 /* config baud rate register */
  95 #define SPRD_CLKD0              0x0024
  96 #define SPRD_CLKD1              0x0028
  97
  98 /* interrupt mask status register */
  99 #define SPRD_IMSR                       0x002C
 100 #define SPRD_IMSR_RX_FIFO_FULL          BIT(0)
 101 #define SPRD_IMSR_TX_FIFO_EMPTY BIT(1)
 102 #define SPRD_IMSR_BREAK_DETECT          BIT(7)
 103 #define SPRD_IMSR_TIMEOUT               BIT(13)
 104
 105 struct reg_backup {
 106         u32 ien;
 107         u32 ctrl0;
 108         u32 ctrl1;
 109         u32 ctrl2;
 110         u32 clkd0;
 111         u32 clkd1;
 112         u32 dspwait;
 113 };
 114
 115 struct sprd_uart_port {
 116         struct uart_port port;
 117         struct reg_backup reg_bak;
 118         char name[16];
 119 };
 120
 121 static struct sprd_uart_port *sprd_port[UART_NR_MAX];
 122 static int sprd_ports_num;
 123
 124 static inline unsigned int serial_in(struct uart_port *port, int offset)
 125 {
 126         return readl_relaxed(port->membase + offset);
 127 }
 128
 129 static inline void serial_out(struct uart_port *port, int offset, int value)
 130 {
 131         writel_relaxed(value, port->membase + offset);
 132 }
 133
 134 static unsigned int sprd_tx_empty(struct uart_port *port)
 135 {
 136         if (serial_in(port, SPRD_STS1) & 0xff00)
 137                 return 0;
 138         else
 139                 return TIOCSER_TEMT;
 140 }
 141
 142 static unsigned int sprd_get_mctrl(struct uart_port *port)
 143 {
 144         return TIOCM_DSR | TIOCM_CTS;
 145 }
 146
 147 static void sprd_set_mctrl(struct uart_port *port, unsigned int mctrl)
 148 {
 149         /* nothing to do */
 150 }
 151
 152 static void sprd_stop_tx(struct uart_port *port)
 153 {
 154         unsigned int ien, iclr;
 155
 156         iclr = serial_in(port, SPRD_ICLR);
 157         ien = serial_in(port, SPRD_IEN);
 158
 159         iclr |= SPRD_IEN_TX_EMPTY;
 160         ien &= ~SPRD_IEN_TX_EMPTY;
 161
 162         serial_out(port, SPRD_ICLR, iclr);
 163         serial_out(port, SPRD_IEN, ien);
 164 }
 165
 166 static void sprd_start_tx(struct uart_port *port)
 167 {
 168         unsigned int ien;
 169
 170         ien = serial_in(port, SPRD_IEN);
 171         if (!(ien & SPRD_IEN_TX_EMPTY)) {
 172                 ien |= SPRD_IEN_TX_EMPTY;
 173                 serial_out(port, SPRD_IEN, ien);
 174         }
 175 }
 176
 177 static void sprd_stop_rx(struct uart_port *port)
 178 {
 179         unsigned int ien, iclr;
 180
 181         iclr = serial_in(port, SPRD_ICLR);
 182         ien = serial_in(port, SPRD_IEN);
 183
 184         ien &= ~(SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT);
 185         iclr |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT;
 186
 187         serial_out(port, SPRD_IEN, ien);
 188         serial_out(port, SPRD_ICLR, iclr);
 189 }
 190
 191 /* The Sprd serial does not support this function. */
 192 static void sprd_break_ctl(struct uart_port *port, int break_state)
 193 {
 194         /* nothing to do */
 195 }
 196
 197 static int handle_lsr_errors(struct uart_port *port,
 198                              unsigned int *flag,
 199                              unsigned int *lsr)
 200 {
 201         int ret = 0;
 202
 203         /* statistics */
 204         if (*lsr & SPRD_LSR_BI) {
 205                 *lsr &= ~(SPRD_LSR_FE | SPRD_LSR_PE);
 206                 port->icount.brk++;
 207                 ret = uart_handle_break(port);
 208                 if (ret)
 209                         return ret;
 210         } else if (*lsr & SPRD_LSR_PE)
 211                 port->icount.parity++;
 212         else if (*lsr & SPRD_LSR_FE)
 213                 port->icount.frame++;
 214         if (*lsr & SPRD_LSR_OE)
 215                 port->icount.overrun++;
 216
 217         /* mask off conditions which should be ignored */
 218         *lsr &= port->read_status_mask;
 219         if (*lsr & SPRD_LSR_BI)
 220                 *flag = TTY_BREAK;
 221         else if (*lsr & SPRD_LSR_PE)
 222                 *flag = TTY_PARITY;
 223         else if (*lsr & SPRD_LSR_FE)
 224                 *flag = TTY_FRAME;
 225
 226         return ret;
 227 }
 228
 229 static inline void sprd_rx(struct uart_port *port)
 230 {
 231         struct tty_port *tty = &port->state->port;
 232         unsigned int ch, flag, lsr, max_count = SPRD_TIMEOUT;
 233
 234         while ((serial_in(port, SPRD_STS1) & 0x00ff) && max_count--) {
 235                 lsr = serial_in(port, SPRD_LSR);
 236                 ch = serial_in(port, SPRD_RXD);
 237                 flag = TTY_NORMAL;
 238                 port->icount.rx++;
 239
 240                 if (lsr & (SPRD_LSR_BI | SPRD_LSR_PE |
 241                         SPRD_LSR_FE | SPRD_LSR_OE))
 242                         if (handle_lsr_errors(port, &lsr, &flag))
 243                                 continue;
 244                 if (uart_handle_sysrq_char(port, ch))
 245                         continue;
 246
 247                 uart_insert_char(port, lsr, SPRD_LSR_OE, ch, flag);
 248         }
 249
 250         tty_flip_buffer_push(tty);
 251 }
 252
 253 static inline void sprd_tx(struct uart_port *port)
 254 {
 255         struct circ_buf *xmit = &port->state->xmit;
 256         int count;
 257
 258         if (port->x_char) {
 259                 serial_out(port, SPRD_TXD, port->x_char);
 260                 port->icount.tx++;
 261                 port->x_char = 0;
 262                 return;
 263         }
 264
 265         if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
 266                 sprd_stop_tx(port);
 267                 return;
 268         }
 269
 270         count = THLD_TX_EMPTY;
 271         do {
 272                 serial_out(port, SPRD_TXD, xmit->buf[xmit->tail]);
 273                 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 274                 port->icount.tx++;
 275                 if (uart_circ_empty(xmit))
 276                         break;
 277         } while (--count > 0);
 278
 279         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 280                 uart_write_wakeup(port);
 281
 282         if (uart_circ_empty(xmit))
 283                 sprd_stop_tx(port);
 284 }
 285
 286 /* this handles the interrupt from one port */
 287 static irqreturn_t sprd_handle_irq(int irq, void *dev_id)
 288 {
 289         struct uart_port *port = dev_id;
 290         unsigned int ims;
 291
 292         spin_lock(&port->lock);
 293
 294         ims = serial_in(port, SPRD_IMSR);
 295
 296         if (!ims) {
 297                 spin_unlock(&port->lock);
 298                 return IRQ_NONE;
 299         }
 300
 301         serial_out(port, SPRD_ICLR, ~0);
 302
 303         if (ims & (SPRD_IMSR_RX_FIFO_FULL |
 304                 SPRD_IMSR_BREAK_DETECT | SPRD_IMSR_TIMEOUT))
 305                 sprd_rx(port);
 306
 307         if (ims & SPRD_IMSR_TX_FIFO_EMPTY)
 308                 sprd_tx(port);
 309
 310         spin_unlock(&port->lock);
 311
 312         return IRQ_HANDLED;
 313 }
 314
 315 static int sprd_startup(struct uart_port *port)
 316 {
 317         int ret = 0;
 318         unsigned int ien, fc;
 319         unsigned int timeout;
 320         struct sprd_uart_port *sp;
 321         unsigned long flags;
 322
 323         serial_out(port, SPRD_CTL2, ((THLD_TX_EMPTY << 8) | THLD_RX_FULL));
 324
 325         /* clear rx fifo */
 326         timeout = SPRD_TIMEOUT;
 327         while (timeout-- && serial_in(port, SPRD_STS1) & 0x00ff)
 328                 serial_in(port, SPRD_RXD);
 329
 330         /* clear tx fifo */
 331         timeout = SPRD_TIMEOUT;
 332         while (timeout-- && serial_in(port, SPRD_STS1) & 0xff00)
 333                 cpu_relax();
 334
 335         /* clear interrupt */
 336         serial_out(port, SPRD_IEN, 0);
 337         serial_out(port, SPRD_ICLR, ~0);
 338
 339         /* allocate irq */
 340         sp = container_of(port, struct sprd_uart_port, port);
 341         snprintf(sp->name, sizeof(sp->name), "sprd_serial%d", port->line);
 342         ret = devm_request_irq(port->dev, port->irq, sprd_handle_irq,
 343                                 IRQF_SHARED, sp->name, port);
 344         if (ret) {
 345                 dev_err(port->dev, "fail to request serial irq %d, ret=%d\n",
 346                         port->irq, ret);
 347                 return ret;
 348         }
 349         fc = serial_in(port, SPRD_CTL1);
 350         fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
 351         serial_out(port, SPRD_CTL1, fc);
 352
 353         /* enable interrupt */
 354         spin_lock_irqsave(&port->lock, flags);
 355         ien = serial_in(port, SPRD_IEN);
 356         ien |= SPRD_IEN_RX_FULL | SPRD_IEN_BREAK_DETECT | SPRD_IEN_TIMEOUT;
 357         serial_out(port, SPRD_IEN, ien);
 358         spin_unlock_irqrestore(&port->lock, flags);
 359
 360         return 0;
 361 }
 362
 363 static void sprd_shutdown(struct uart_port *port)
 364 {
 365         serial_out(port, SPRD_IEN, 0);
 366         serial_out(port, SPRD_ICLR, ~0);
 367         devm_free_irq(port->dev, port->irq, port);
 368 }
 369
 370 static void sprd_set_termios(struct uart_port *port,
 371                                     struct ktermios *termios,
 372                                     struct ktermios *old)
 373 {
 374         unsigned int baud, quot;
 375         unsigned int lcr = 0, fc;
 376         unsigned long flags;
 377
 378         /* ask the core to calculate the divisor for us */
 379         baud = uart_get_baud_rate(port, termios, old, 0, SPRD_BAUD_IO_LIMIT);
 380
 381         quot = (unsigned int)((port->uartclk + baud / 2) / baud);
 382
 383         /* set data length */
 384         switch (termios->c_cflag & CSIZE) {
 385         case CS5:
 386                 lcr |= SPRD_LCR_DATA_LEN5;
 387                 break;
 388         case CS6:
 389                 lcr |= SPRD_LCR_DATA_LEN6;
 390                 break;
 391         case CS7:
 392                 lcr |= SPRD_LCR_DATA_LEN7;
 393                 break;
 394         case CS8:
 395         default:
 396                 lcr |= SPRD_LCR_DATA_LEN8;
 397                 break;
 398         }
 399
 400         /* calculate stop bits */
 401         lcr &= ~(SPRD_LCR_STOP_1BIT | SPRD_LCR_STOP_2BIT);
 402         if (termios->c_cflag & CSTOPB)
 403                 lcr |= SPRD_LCR_STOP_2BIT;
 404         else
 405                 lcr |= SPRD_LCR_STOP_1BIT;
 406
 407         /* calculate parity */
 408         lcr &= ~SPRD_LCR_PARITY;
 409         termios->c_cflag &= ~CMSPAR;    /* no support mark/space */
 410         if (termios->c_cflag & PARENB) {
 411                 lcr |= SPRD_LCR_PARITY_EN;
 412                 if (termios->c_cflag & PARODD)
 413                         lcr |= SPRD_LCR_ODD_PAR;
 414                 else
 415                         lcr |= SPRD_LCR_EVEN_PAR;
 416         }
 417
 418         spin_lock_irqsave(&port->lock, flags);
 419
 420         /* update the per-port timeout */
 421         uart_update_timeout(port, termios->c_cflag, baud);
 422
 423         port->read_status_mask = SPRD_LSR_OE;
 424         if (termios->c_iflag & INPCK)
 425                 port->read_status_mask |= SPRD_LSR_FE | SPRD_LSR_PE;
 426         if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 427                 port->read_status_mask |= SPRD_LSR_BI;
 428
 429         /* characters to ignore */
 430         port->ignore_status_mask = 0;
 431         if (termios->c_iflag & IGNPAR)
 432                 port->ignore_status_mask |= SPRD_LSR_PE | SPRD_LSR_FE;
 433         if (termios->c_iflag & IGNBRK) {
 434                 port->ignore_status_mask |= SPRD_LSR_BI;
 435                 /*
 436                  * If we're ignoring parity and break indicators,
 437                  * ignore overruns too (for real raw support).
 438                  */
 439                 if (termios->c_iflag & IGNPAR)
 440                         port->ignore_status_mask |= SPRD_LSR_OE;
 441         }
 442
 443         /* flow control */
 444         fc = serial_in(port, SPRD_CTL1);
 445         fc &= ~(RX_HW_FLOW_CTL_THLD | RX_HW_FLOW_CTL_EN | TX_HW_FLOW_CTL_EN);
 446         if (termios->c_cflag & CRTSCTS) {
 447                 fc |= RX_HW_FLOW_CTL_THLD;
 448                 fc |= RX_HW_FLOW_CTL_EN;
 449                 fc |= TX_HW_FLOW_CTL_EN;
 450         }
 451
 452         /* clock divider bit0~bit15 */
 453         serial_out(port, SPRD_CLKD0, quot & 0xffff);
 454
 455         /* clock divider bit16~bit20 */
 456         serial_out(port, SPRD_CLKD1, (quot & 0x1f0000) >> 16);
 457         serial_out(port, SPRD_LCR, lcr);
 458         fc |= RX_TOUT_THLD_DEF | RX_HFC_THLD_DEF;
 459         serial_out(port, SPRD_CTL1, fc);
 460
 461         spin_unlock_irqrestore(&port->lock, flags);
 462
 463         /* Don't rewrite B0 */
 464         if (tty_termios_baud_rate(termios))
 465                 tty_termios_encode_baud_rate(termios, baud, baud);
 466 }
 467
 468 static const char *sprd_type(struct uart_port *port)
 469 {
 470         return "SPX";
 471 }
 472
 473 static void sprd_release_port(struct uart_port *port)
 474 {
 475         /* nothing to do */
 476 }
 477
 478 static int sprd_request_port(struct uart_port *port)
 479 {
 480         return 0;
 481 }
 482
 483 static void sprd_config_port(struct uart_port *port, int flags)
 484 {
 485         if (flags & UART_CONFIG_TYPE)
 486                 port->type = PORT_SPRD;
 487 }
 488
 489 static int sprd_verify_port(struct uart_port *port,
 490                                    struct serial_struct *ser)
 491 {
 492         if (ser->type != PORT_SPRD)
 493                 return -EINVAL;
 494         if (port->irq != ser->irq)
 495                 return -EINVAL;
 496         return 0;
 497 }
 498
 499 static struct uart_ops serial_sprd_ops = {
 500         .tx_empty = sprd_tx_empty,
 501         .get_mctrl = sprd_get_mctrl,
 502         .set_mctrl = sprd_set_mctrl,
 503         .stop_tx = sprd_stop_tx,
 504         .start_tx = sprd_start_tx,
 505         .stop_rx = sprd_stop_rx,
 506         .break_ctl = sprd_break_ctl,
 507         .startup = sprd_startup,
 508         .shutdown = sprd_shutdown,
 509         .set_termios = sprd_set_termios,
 510         .type = sprd_type,
 511         .release_port = sprd_release_port,
 512         .request_port = sprd_request_port,
 513         .config_port = sprd_config_port,
 514         .verify_port = sprd_verify_port,
 515 };
 516
 517 #ifdef CONFIG_SERIAL_SPRD_CONSOLE
 518 static inline void wait_for_xmitr(struct uart_port *port)
 519 {
 520         unsigned int status, tmout = 10000;
 521
 522         /* wait up to 10ms for the character(s) to be sent */
 523         do {
 524                 status = serial_in(port, SPRD_STS1);
 525                 if (--tmout == 0)
 526                         break;
 527                 udelay(1);
 528         } while (status & 0xff00);
 529 }
 530
 531 static void sprd_console_putchar(struct uart_port *port, int ch)
 532 {
 533         wait_for_xmitr(port);
 534         serial_out(port, SPRD_TXD, ch);
 535 }
 536
 537 static void sprd_console_write(struct console *co, const char *s,
 538                                       unsigned int count)
 539 {
 540         struct uart_port *port = &sprd_port[co->index]->port;
 541         int locked = 1;
 542         unsigned long flags;
 543
 544         if (port->sysrq)
 545                 locked = 0;
 546         else if (oops_in_progress)
 547                 locked = spin_trylock_irqsave(&port->lock, flags);
 548         else
 549                 spin_lock_irqsave(&port->lock, flags);
 550
 551         uart_console_write(port, s, count, sprd_console_putchar);
 552
 553         /* wait for transmitter to become empty */
 554         wait_for_xmitr(port);
 555
 556         if (locked)
 557                 spin_unlock_irqrestore(&port->lock, flags);
 558 }
 559
 560 static int __init sprd_console_setup(struct console *co, char *options)
 561 {
 562         struct uart_port *port;
 563         int baud = 115200;
 564         int bits = 8;
 565         int parity = 'n';
 566         int flow = 'n';
 567
 568         if (co->index >= UART_NR_MAX || co->index < 0)
 569                 co->index = 0;
 570
 571         port = &sprd_port[co->index]->port;
 572         if (port == NULL) {
 573                 pr_info("serial port %d not yet initialized\n", co->index);
 574                 return -ENODEV;
 575         }
 576         if (options)
 577                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 578
 579         return uart_set_options(port, co, baud, parity, bits, flow);
 580 }
 581
 582 static struct uart_driver sprd_uart_driver;
 583 static struct console sprd_console = {
 584         .name = SPRD_TTY_NAME,
 585         .write = sprd_console_write,
 586         .device = uart_console_device,
 587         .setup = sprd_console_setup,
 588         .flags = CON_PRINTBUFFER,
 589         .index = -1,
 590         .data = &sprd_uart_driver,
 591 };
 592
 593 #define SPRD_CONSOLE    (&sprd_console)
 594
 595 /* Support for earlycon */
 596 static void sprd_putc(struct uart_port *port, int c)
 597 {
 598         unsigned int timeout = SPRD_TIMEOUT;
 599
 600         while (timeout-- &&
 601                    !(readl(port->membase + SPRD_LSR) & SPRD_LSR_TX_OVER))
 602                 cpu_relax();
 603
 604         writeb(c, port->membase + SPRD_TXD);
 605 }
 606
 607 static void sprd_early_write(struct console *con, const char *s,
 608                                     unsigned n)
 609 {
 610         struct earlycon_device *dev = con->data;
 611
 612         uart_console_write(&dev->port, s, n, sprd_putc);
 613 }
 614
 615 static int __init sprd_early_console_setup(
 616                                 struct earlycon_device *device,
 617                                 const char *opt)
 618 {
 619         if (!device->port.membase)
 620                 return -ENODEV;
 621
 622         device->con->write = sprd_early_write;
 623         return 0;
 624 }
 625
 626 EARLYCON_DECLARE(sprd_serial, sprd_early_console_setup);
 627 OF_EARLYCON_DECLARE(sprd_serial, "sprd,sc9836-uart",
 628                     sprd_early_console_setup);
 629
 630 #else /* !CONFIG_SERIAL_SPRD_CONSOLE */
 631 #define SPRD_CONSOLE            NULL
 632 #endif
 633
 634 static struct uart_driver sprd_uart_driver = {
 635         .owner = THIS_MODULE,
 636         .driver_name = "sprd_serial",
 637         .dev_name = SPRD_TTY_NAME,
 638         .major = 0,
 639         .minor = 0,
 640         .nr = UART_NR_MAX,
 641         .cons = SPRD_CONSOLE,
 642 };
 643
 644 static int sprd_probe_dt_alias(int index, struct device *dev)
 645 {
 646         struct device_node *np;
 647         int ret = index;
 648
 649         if (!IS_ENABLED(CONFIG_OF))
 650                 return ret;
 651
 652         np = dev->of_node;
 653         if (!np)
 654                 return ret;
 655
 656         ret = of_alias_get_id(np, "serial");
 657         if (IS_ERR_VALUE(ret))
 658                 ret = index;
 659         else if (ret >= ARRAY_SIZE(sprd_port) || sprd_port[ret] != NULL) {
 660                 dev_warn(dev, "requested serial port %d not available.\n", ret);
 661                 ret = index;
 662         }
 663
 664         return ret;
 665 }
 666
 667 static int sprd_remove(struct platform_device *dev)
 668 {
 669         struct sprd_uart_port *sup = platform_get_drvdata(dev);
 670
 671         if (sup) {
 672                 uart_remove_one_port(&sprd_uart_driver, &sup->port);
 673                 sprd_port[sup->port.line] = NULL;
 674                 sprd_ports_num--;
 675         }
 676
 677         if (!sprd_ports_num)
 678                 uart_unregister_driver(&sprd_uart_driver);
 679
 680         return 0;
 681 }
 682
 683 static int sprd_probe(struct platform_device *pdev)
 684 {
 685         struct resource *res;
 686         struct uart_port *up;
 687         struct clk *clk;
 688         int irq;
 689         int index;
 690         int ret;
 691
 692         for (index = 0; index < ARRAY_SIZE(sprd_port); index++)
 693                 if (sprd_port[index] == NULL)
 694                         break;
 695
 696         if (index == ARRAY_SIZE(sprd_port))
 697                 return -EBUSY;
 698
 699         index = sprd_probe_dt_alias(index, &pdev->dev);
 700
 701         sprd_port[index] = devm_kzalloc(&pdev->dev,
 702                 sizeof(*sprd_port[index]), GFP_KERNEL);
 703         if (!sprd_port[index])
 704                 return -ENOMEM;
 705
 706         up = &sprd_port[index]->port;
 707         up->dev = &pdev->dev;
 708         up->line = index;
 709         up->type = PORT_SPRD;
 710         up->iotype = SERIAL_IO_PORT;
 711         up->uartclk = SPRD_DEF_RATE;
 712         up->fifosize = SPRD_FIFO_SIZE;
 713         up->ops = &serial_sprd_ops;
 714         up->flags = UPF_BOOT_AUTOCONF;
 715
 716         clk = devm_clk_get(&pdev->dev, NULL);
 717         if (!IS_ERR(clk))
 718                 up->uartclk = clk_get_rate(clk);
 719
 720         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 721         if (!res) {
 722                 dev_err(&pdev->dev, "not provide mem resource\n");
 723                 return -ENODEV;
 724         }
 725         up->mapbase = res->start;
 726         up->membase = devm_ioremap_resource(&pdev->dev, res);
 727         if (IS_ERR(up->membase))
 728                 return PTR_ERR(up->membase);
 729
 730         irq = platform_get_irq(pdev, 0);
 731         if (irq < 0) {
 732                 dev_err(&pdev->dev, "not provide irq resource\n");
 733                 return -ENODEV;
 734         }
 735         up->irq = irq;
 736
 737         if (!sprd_ports_num) {
 738                 ret = uart_register_driver(&sprd_uart_driver);
 739                 if (ret < 0) {
 740                         pr_err("Failed to register SPRD-UART driver\n");
 741                         return ret;
 742                 }
 743         }
 744         sprd_ports_num++;
 745
 746         ret = uart_add_one_port(&sprd_uart_driver, up);
 747         if (ret) {
 748                 sprd_port[index] = NULL;
 749                 sprd_remove(pdev);
 750         }
 751
 752         platform_set_drvdata(pdev, up);
 753
 754         return ret;
 755 }
 756
 757 static int sprd_suspend(struct device *dev)
 758 {
 759         struct sprd_uart_port *sup = dev_get_drvdata(dev);
 760
 761         uart_suspend_port(&sprd_uart_driver, &sup->port);
 762
 763         return 0;
 764 }
 765
 766 static int sprd_resume(struct device *dev)
 767 {
 768         struct sprd_uart_port *sup = dev_get_drvdata(dev);
 769
 770         uart_resume_port(&sprd_uart_driver, &sup->port);
 771
 772         return 0;
 773 }
 774
 775 static SIMPLE_DEV_PM_OPS(sprd_pm_ops, sprd_suspend, sprd_resume);
 776
 777 static const struct of_device_id serial_ids[] = {
 778         {.compatible = "sprd,sc9836-uart",},
 779         {}
 780 };
 781
 782 static struct platform_driver sprd_platform_driver = {
 783         .probe          = sprd_probe,
 784         .remove         = sprd_remove,
 785         .driver         = {
 786                 .name   = "sprd_serial",
 787                 .of_match_table = of_match_ptr(serial_ids),
 788                 .pm     = &sprd_pm_ops,
 789         },
 790 };
 791
 792 module_platform_driver(sprd_platform_driver);
 793
 794 MODULE_LICENSE("GPL v2");
 795 MODULE_DESCRIPTION("Spreadtrum SoC serial driver series");