linux/drivers/tty/serial/amba-pl010.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 *  Driver for AMBA serial ports
   4 *
   5 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
   6 *
   7 *  Copyright 1999 ARM Limited
   8 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
   9 *
  10 * This is a generic driver for ARM AMBA-type serial ports.  They
  11 * have a lot of 16550-like features, but are not register compatible.
  12 * Note that although they do have CTS, DCD and DSR inputs, they do
  13 * not have an RI input, nor do they have DTR or RTS outputs.  If
  14 * required, these have to be supplied via some other means (eg, GPIO)
  15 * and hooked into this driver.
  16 */
  17
  18#include <linux/module.h>
  19#include <linux/ioport.h>
  20#include <linux/init.h>
  21#include <linux/console.h>
  22#include <linux/sysrq.h>
  23#include <linux/device.h>
  24#include <linux/tty.h>
  25#include <linux/tty_flip.h>
  26#include <linux/serial_core.h>
  27#include <linux/serial.h>
  28#include <linux/amba/bus.h>
  29#include <linux/amba/serial.h>
  30#include <linux/clk.h>
  31#include <linux/slab.h>
  32#include <linux/io.h>
  33
  34#define UART_NR         8
  35
  36#define SERIAL_AMBA_MAJOR       204
  37#define SERIAL_AMBA_MINOR       16
  38#define SERIAL_AMBA_NR          UART_NR
  39
  40#define AMBA_ISR_PASS_LIMIT     256
  41
  42#define UART_RX_DATA(s)         (((s) & UART01x_FR_RXFE) == 0)
  43#define UART_TX_READY(s)        (((s) & UART01x_FR_TXFF) == 0)
  44
  45#define UART_DUMMY_RSR_RX       256
  46#define UART_PORT_SIZE          64
  47
  48/*
  49 * We wrap our port structure around the generic uart_port.
  50 */
  51struct uart_amba_port {
  52        struct uart_port        port;
  53        struct clk              *clk;
  54        struct amba_device      *dev;
  55        struct amba_pl010_data  *data;
  56        unsigned int            old_status;
  57};
  58
  59static void pl010_stop_tx(struct uart_port *port)
  60{
  61        struct uart_amba_port *uap =
  62                container_of(port, struct uart_amba_port, port);
  63        unsigned int cr;
  64
  65        cr = readb(uap->port.membase + UART010_CR);
  66        cr &= ~UART010_CR_TIE;
  67        writel(cr, uap->port.membase + UART010_CR);
  68}
  69
  70static void pl010_start_tx(struct uart_port *port)
  71{
  72        struct uart_amba_port *uap =
  73                container_of(port, struct uart_amba_port, port);
  74        unsigned int cr;
  75
  76        cr = readb(uap->port.membase + UART010_CR);
  77        cr |= UART010_CR_TIE;
  78        writel(cr, uap->port.membase + UART010_CR);
  79}
  80
  81static void pl010_stop_rx(struct uart_port *port)
  82{
  83        struct uart_amba_port *uap =
  84                container_of(port, struct uart_amba_port, port);
  85        unsigned int cr;
  86
  87        cr = readb(uap->port.membase + UART010_CR);
  88        cr &= ~(UART010_CR_RIE | UART010_CR_RTIE);
  89        writel(cr, uap->port.membase + UART010_CR);
  90}
  91
  92static void pl010_disable_ms(struct uart_port *port)
  93{
  94        struct uart_amba_port *uap = (struct uart_amba_port *)port;
  95        unsigned int cr;
  96
  97        cr = readb(uap->port.membase + UART010_CR);
  98        cr &= ~UART010_CR_MSIE;
  99        writel(cr, uap->port.membase + UART010_CR);
 100}
 101
 102static void pl010_enable_ms(struct uart_port *port)
 103{
 104        struct uart_amba_port *uap =
 105                container_of(port, struct uart_amba_port, port);
 106        unsigned int cr;
 107
 108        cr = readb(uap->port.membase + UART010_CR);
 109        cr |= UART010_CR_MSIE;
 110        writel(cr, uap->port.membase + UART010_CR);
 111}
 112
 113static void pl010_rx_chars(struct uart_amba_port *uap)
 114{
 115        unsigned int status, ch, flag, rsr, max_count = 256;
 116
 117        status = readb(uap->port.membase + UART01x_FR);
 118        while (UART_RX_DATA(status) && max_count--) {
 119                ch = readb(uap->port.membase + UART01x_DR);
 120                flag = TTY_NORMAL;
 121
 122                uap->port.icount.rx++;
 123
 124                /*
 125                 * Note that the error handling code is
 126                 * out of the main execution path
 127                 */
 128                rsr = readb(uap->port.membase + UART01x_RSR) | UART_DUMMY_RSR_RX;
 129                if (unlikely(rsr & UART01x_RSR_ANY)) {
 130                        writel(0, uap->port.membase + UART01x_ECR);
 131
 132                        if (rsr & UART01x_RSR_BE) {
 133                                rsr &= ~(UART01x_RSR_FE | UART01x_RSR_PE);
 134                                uap->port.icount.brk++;
 135                                if (uart_handle_break(&uap->port))
 136                                        goto ignore_char;
 137                        } else if (rsr & UART01x_RSR_PE)
 138                                uap->port.icount.parity++;
 139                        else if (rsr & UART01x_RSR_FE)
 140                                uap->port.icount.frame++;
 141                        if (rsr & UART01x_RSR_OE)
 142                                uap->port.icount.overrun++;
 143
 144                        rsr &= uap->port.read_status_mask;
 145
 146                        if (rsr & UART01x_RSR_BE)
 147                                flag = TTY_BREAK;
 148                        else if (rsr & UART01x_RSR_PE)
 149                                flag = TTY_PARITY;
 150                        else if (rsr & UART01x_RSR_FE)
 151                                flag = TTY_FRAME;
 152                }
 153
 154                if (uart_handle_sysrq_char(&uap->port, ch))
 155                        goto ignore_char;
 156
 157                uart_insert_char(&uap->port, rsr, UART01x_RSR_OE, ch, flag);
 158
 159        ignore_char:
 160                status = readb(uap->port.membase + UART01x_FR);
 161        }
 162        tty_flip_buffer_push(&uap->port.state->port);
 163}
 164
 165static void pl010_tx_chars(struct uart_amba_port *uap)
 166{
 167        struct circ_buf *xmit = &uap->port.state->xmit;
 168        int count;
 169
 170        if (uap->port.x_char) {
 171                writel(uap->port.x_char, uap->port.membase + UART01x_DR);
 172                uap->port.icount.tx++;
 173                uap->port.x_char = 0;
 174                return;
 175        }
 176        if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
 177                pl010_stop_tx(&uap->port);
 178                return;
 179        }
 180
 181        count = uap->port.fifosize >> 1;
 182        do {
 183                writel(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
 184                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 185                uap->port.icount.tx++;
 186                if (uart_circ_empty(xmit))
 187                        break;
 188        } while (--count > 0);
 189
 190        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 191                uart_write_wakeup(&uap->port);
 192
 193        if (uart_circ_empty(xmit))
 194                pl010_stop_tx(&uap->port);
 195}
 196
 197static void pl010_modem_status(struct uart_amba_port *uap)
 198{
 199        unsigned int status, delta;
 200
 201        writel(0, uap->port.membase + UART010_ICR);
 202
 203        status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
 204
 205        delta = status ^ uap->old_status;
 206        uap->old_status = status;
 207
 208        if (!delta)
 209                return;
 210
 211        if (delta & UART01x_FR_DCD)
 212                uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
 213
 214        if (delta & UART01x_FR_DSR)
 215                uap->port.icount.dsr++;
 216
 217        if (delta & UART01x_FR_CTS)
 218                uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
 219
 220        wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
 221}
 222
 223static irqreturn_t pl010_int(int irq, void *dev_id)
 224{
 225        struct uart_amba_port *uap = dev_id;
 226        unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
 227        int handled = 0;
 228
 229        spin_lock(&uap->port.lock);
 230
 231        status = readb(uap->port.membase + UART010_IIR);
 232        if (status) {
 233                do {
 234                        if (status & (UART010_IIR_RTIS | UART010_IIR_RIS))
 235                                pl010_rx_chars(uap);
 236                        if (status & UART010_IIR_MIS)
 237                                pl010_modem_status(uap);
 238                        if (status & UART010_IIR_TIS)
 239                                pl010_tx_chars(uap);
 240
 241                        if (pass_counter-- == 0)
 242                                break;
 243
 244                        status = readb(uap->port.membase + UART010_IIR);
 245                } while (status & (UART010_IIR_RTIS | UART010_IIR_RIS |
 246                                   UART010_IIR_TIS));
 247                handled = 1;
 248        }
 249
 250        spin_unlock(&uap->port.lock);
 251
 252        return IRQ_RETVAL(handled);
 253}
 254
 255static unsigned int pl010_tx_empty(struct uart_port *port)
 256{
 257        struct uart_amba_port *uap =
 258                container_of(port, struct uart_amba_port, port);
 259        unsigned int status = readb(uap->port.membase + UART01x_FR);
 260        return status & UART01x_FR_BUSY ? 0 : TIOCSER_TEMT;
 261}
 262
 263static unsigned int pl010_get_mctrl(struct uart_port *port)
 264{
 265        struct uart_amba_port *uap =
 266                container_of(port, struct uart_amba_port, port);
 267        unsigned int result = 0;
 268        unsigned int status;
 269
 270        status = readb(uap->port.membase + UART01x_FR);
 271        if (status & UART01x_FR_DCD)
 272                result |= TIOCM_CAR;
 273        if (status & UART01x_FR_DSR)
 274                result |= TIOCM_DSR;
 275        if (status & UART01x_FR_CTS)
 276                result |= TIOCM_CTS;
 277
 278        return result;
 279}
 280
 281static void pl010_set_mctrl(struct uart_port *port, unsigned int mctrl)
 282{
 283        struct uart_amba_port *uap =
 284                container_of(port, struct uart_amba_port, port);
 285
 286        if (uap->data)
 287                uap->data->set_mctrl(uap->dev, uap->port.membase, mctrl);
 288}
 289
 290static void pl010_break_ctl(struct uart_port *port, int break_state)
 291{
 292        struct uart_amba_port *uap =
 293                container_of(port, struct uart_amba_port, port);
 294        unsigned long flags;
 295        unsigned int lcr_h;
 296
 297        spin_lock_irqsave(&uap->port.lock, flags);
 298        lcr_h = readb(uap->port.membase + UART010_LCRH);
 299        if (break_state == -1)
 300                lcr_h |= UART01x_LCRH_BRK;
 301        else
 302                lcr_h &= ~UART01x_LCRH_BRK;
 303        writel(lcr_h, uap->port.membase + UART010_LCRH);
 304        spin_unlock_irqrestore(&uap->port.lock, flags);
 305}
 306
 307static int pl010_startup(struct uart_port *port)
 308{
 309        struct uart_amba_port *uap =
 310                container_of(port, struct uart_amba_port, port);
 311        int retval;
 312
 313        /*
 314         * Try to enable the clock producer.
 315         */
 316        retval = clk_prepare_enable(uap->clk);
 317        if (retval)
 318                goto out;
 319
 320        uap->port.uartclk = clk_get_rate(uap->clk);
 321
 322        /*
 323         * Allocate the IRQ
 324         */
 325        retval = request_irq(uap->port.irq, pl010_int, 0, "uart-pl010", uap);
 326        if (retval)
 327                goto clk_dis;
 328
 329        /*
 330         * initialise the old status of the modem signals
 331         */
 332        uap->old_status = readb(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
 333
 334        /*
 335         * Finally, enable interrupts
 336         */
 337        writel(UART01x_CR_UARTEN | UART010_CR_RIE | UART010_CR_RTIE,
 338               uap->port.membase + UART010_CR);
 339
 340        return 0;
 341
 342 clk_dis:
 343        clk_disable_unprepare(uap->clk);
 344 out:
 345        return retval;
 346}
 347
 348static void pl010_shutdown(struct uart_port *port)
 349{
 350        struct uart_amba_port *uap =
 351                container_of(port, struct uart_amba_port, port);
 352
 353        /*
 354         * Free the interrupt
 355         */
 356        free_irq(uap->port.irq, uap);
 357
 358        /*
 359         * disable all interrupts, disable the port
 360         */
 361        writel(0, uap->port.membase + UART010_CR);
 362
 363        /* disable break condition and fifos */
 364        writel(readb(uap->port.membase + UART010_LCRH) &
 365                ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN),
 366               uap->port.membase + UART010_LCRH);
 367
 368        /*
 369         * Shut down the clock producer
 370         */
 371        clk_disable_unprepare(uap->clk);
 372}
 373
 374static void
 375pl010_set_termios(struct uart_port *port, struct ktermios *termios,
 376                     struct ktermios *old)
 377{
 378        struct uart_amba_port *uap =
 379                container_of(port, struct uart_amba_port, port);
 380        unsigned int lcr_h, old_cr;
 381        unsigned long flags;
 382        unsigned int baud, quot;
 383
 384        /*
 385         * Ask the core to calculate the divisor for us.
 386         */
 387        baud = uart_get_baud_rate(port, termios, old, 0, uap->port.uartclk/16); 
 388        quot = uart_get_divisor(port, baud);
 389
 390        switch (termios->c_cflag & CSIZE) {
 391        case CS5:
 392                lcr_h = UART01x_LCRH_WLEN_5;
 393                break;
 394        case CS6:
 395                lcr_h = UART01x_LCRH_WLEN_6;
 396                break;
 397        case CS7:
 398                lcr_h = UART01x_LCRH_WLEN_7;
 399                break;
 400        default: // CS8
 401                lcr_h = UART01x_LCRH_WLEN_8;
 402                break;
 403        }
 404        if (termios->c_cflag & CSTOPB)
 405                lcr_h |= UART01x_LCRH_STP2;
 406        if (termios->c_cflag & PARENB) {
 407                lcr_h |= UART01x_LCRH_PEN;
 408                if (!(termios->c_cflag & PARODD))
 409                        lcr_h |= UART01x_LCRH_EPS;
 410        }
 411        if (uap->port.fifosize > 1)
 412                lcr_h |= UART01x_LCRH_FEN;
 413
 414        spin_lock_irqsave(&uap->port.lock, flags);
 415
 416        /*
 417         * Update the per-port timeout.
 418         */
 419        uart_update_timeout(port, termios->c_cflag, baud);
 420
 421        uap->port.read_status_mask = UART01x_RSR_OE;
 422        if (termios->c_iflag & INPCK)
 423                uap->port.read_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
 424        if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
 425                uap->port.read_status_mask |= UART01x_RSR_BE;
 426
 427        /*
 428         * Characters to ignore
 429         */
 430        uap->port.ignore_status_mask = 0;
 431        if (termios->c_iflag & IGNPAR)
 432                uap->port.ignore_status_mask |= UART01x_RSR_FE | UART01x_RSR_PE;
 433        if (termios->c_iflag & IGNBRK) {
 434                uap->port.ignore_status_mask |= UART01x_RSR_BE;
 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                        uap->port.ignore_status_mask |= UART01x_RSR_OE;
 441        }
 442
 443        /*
 444         * Ignore all characters if CREAD is not set.
 445         */
 446        if ((termios->c_cflag & CREAD) == 0)
 447                uap->port.ignore_status_mask |= UART_DUMMY_RSR_RX;
 448
 449        /* first, disable everything */
 450        old_cr = readb(uap->port.membase + UART010_CR) & ~UART010_CR_MSIE;
 451
 452        if (UART_ENABLE_MS(port, termios->c_cflag))
 453                old_cr |= UART010_CR_MSIE;
 454
 455        writel(0, uap->port.membase + UART010_CR);
 456
 457        /* Set baud rate */
 458        quot -= 1;
 459        writel((quot & 0xf00) >> 8, uap->port.membase + UART010_LCRM);
 460        writel(quot & 0xff, uap->port.membase + UART010_LCRL);
 461
 462        /*
 463         * ----------v----------v----------v----------v-----
 464         * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
 465         * ----------^----------^----------^----------^-----
 466         */
 467        writel(lcr_h, uap->port.membase + UART010_LCRH);
 468        writel(old_cr, uap->port.membase + UART010_CR);
 469
 470        spin_unlock_irqrestore(&uap->port.lock, flags);
 471}
 472
 473static void pl010_set_ldisc(struct uart_port *port, struct ktermios *termios)
 474{
 475        if (termios->c_line == N_PPS) {
 476                port->flags |= UPF_HARDPPS_CD;
 477                spin_lock_irq(&port->lock);
 478                pl010_enable_ms(port);
 479                spin_unlock_irq(&port->lock);
 480        } else {
 481                port->flags &= ~UPF_HARDPPS_CD;
 482                if (!UART_ENABLE_MS(port, termios->c_cflag)) {
 483                        spin_lock_irq(&port->lock);
 484                        pl010_disable_ms(port);
 485                        spin_unlock_irq(&port->lock);
 486                }
 487        }
 488}
 489
 490static const char *pl010_type(struct uart_port *port)
 491{
 492        return port->type == PORT_AMBA ? "AMBA" : NULL;
 493}
 494
 495/*
 496 * Release the memory region(s) being used by 'port'
 497 */
 498static void pl010_release_port(struct uart_port *port)
 499{
 500        release_mem_region(port->mapbase, UART_PORT_SIZE);
 501}
 502
 503/*
 504 * Request the memory region(s) being used by 'port'
 505 */
 506static int pl010_request_port(struct uart_port *port)
 507{
 508        return request_mem_region(port->mapbase, UART_PORT_SIZE, "uart-pl010")
 509                        != NULL ? 0 : -EBUSY;
 510}
 511
 512/*
 513 * Configure/autoconfigure the port.
 514 */
 515static void pl010_config_port(struct uart_port *port, int flags)
 516{
 517        if (flags & UART_CONFIG_TYPE) {
 518                port->type = PORT_AMBA;
 519                pl010_request_port(port);
 520        }
 521}
 522
 523/*
 524 * verify the new serial_struct (for TIOCSSERIAL).
 525 */
 526static int pl010_verify_port(struct uart_port *port, struct serial_struct *ser)
 527{
 528        int ret = 0;
 529        if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
 530                ret = -EINVAL;
 531        if (ser->irq < 0 || ser->irq >= nr_irqs)
 532                ret = -EINVAL;
 533        if (ser->baud_base < 9600)
 534                ret = -EINVAL;
 535        return ret;
 536}
 537
 538static const struct uart_ops amba_pl010_pops = {
 539        .tx_empty       = pl010_tx_empty,
 540        .set_mctrl      = pl010_set_mctrl,
 541        .get_mctrl      = pl010_get_mctrl,
 542        .stop_tx        = pl010_stop_tx,
 543        .start_tx       = pl010_start_tx,
 544        .stop_rx        = pl010_stop_rx,
 545        .enable_ms      = pl010_enable_ms,
 546        .break_ctl      = pl010_break_ctl,
 547        .startup        = pl010_startup,
 548        .shutdown       = pl010_shutdown,
 549        .set_termios    = pl010_set_termios,
 550        .set_ldisc      = pl010_set_ldisc,
 551        .type           = pl010_type,
 552        .release_port   = pl010_release_port,
 553        .request_port   = pl010_request_port,
 554        .config_port    = pl010_config_port,
 555        .verify_port    = pl010_verify_port,
 556};
 557
 558static struct uart_amba_port *amba_ports[UART_NR];
 559
 560#ifdef CONFIG_SERIAL_AMBA_PL010_CONSOLE
 561
 562static void pl010_console_putchar(struct uart_port *port, int ch)
 563{
 564        struct uart_amba_port *uap =
 565                container_of(port, struct uart_amba_port, port);
 566        unsigned int status;
 567
 568        do {
 569                status = readb(uap->port.membase + UART01x_FR);
 570                barrier();
 571        } while (!UART_TX_READY(status));
 572        writel(ch, uap->port.membase + UART01x_DR);
 573}
 574
 575static void
 576pl010_console_write(struct console *co, const char *s, unsigned int count)
 577{
 578        struct uart_amba_port *uap = amba_ports[co->index];
 579        unsigned int status, old_cr;
 580
 581        clk_enable(uap->clk);
 582
 583        /*
 584         *      First save the CR then disable the interrupts
 585         */
 586        old_cr = readb(uap->port.membase + UART010_CR);
 587        writel(UART01x_CR_UARTEN, uap->port.membase + UART010_CR);
 588
 589        uart_console_write(&uap->port, s, count, pl010_console_putchar);
 590
 591        /*
 592         *      Finally, wait for transmitter to become empty
 593         *      and restore the TCR
 594         */
 595        do {
 596                status = readb(uap->port.membase + UART01x_FR);
 597                barrier();
 598        } while (status & UART01x_FR_BUSY);
 599        writel(old_cr, uap->port.membase + UART010_CR);
 600
 601        clk_disable(uap->clk);
 602}
 603
 604static void __init
 605pl010_console_get_options(struct uart_amba_port *uap, int *baud,
 606                             int *parity, int *bits)
 607{
 608        if (readb(uap->port.membase + UART010_CR) & UART01x_CR_UARTEN) {
 609                unsigned int lcr_h, quot;
 610                lcr_h = readb(uap->port.membase + UART010_LCRH);
 611
 612                *parity = 'n';
 613                if (lcr_h & UART01x_LCRH_PEN) {
 614                        if (lcr_h & UART01x_LCRH_EPS)
 615                                *parity = 'e';
 616                        else
 617                                *parity = 'o';
 618                }
 619
 620                if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
 621                        *bits = 7;
 622                else
 623                        *bits = 8;
 624
 625                quot = readb(uap->port.membase + UART010_LCRL) |
 626                       readb(uap->port.membase + UART010_LCRM) << 8;
 627                *baud = uap->port.uartclk / (16 * (quot + 1));
 628        }
 629}
 630
 631static int __init pl010_console_setup(struct console *co, char *options)
 632{
 633        struct uart_amba_port *uap;
 634        int baud = 38400;
 635        int bits = 8;
 636        int parity = 'n';
 637        int flow = 'n';
 638        int ret;
 639
 640        /*
 641         * Check whether an invalid uart number has been specified, and
 642         * if so, search for the first available port that does have
 643         * console support.
 644         */
 645        if (co->index >= UART_NR)
 646                co->index = 0;
 647        uap = amba_ports[co->index];
 648        if (!uap)
 649                return -ENODEV;
 650
 651        ret = clk_prepare(uap->clk);
 652        if (ret)
 653                return ret;
 654
 655        uap->port.uartclk = clk_get_rate(uap->clk);
 656
 657        if (options)
 658                uart_parse_options(options, &baud, &parity, &bits, &flow);
 659        else
 660                pl010_console_get_options(uap, &baud, &parity, &bits);
 661
 662        return uart_set_options(&uap->port, co, baud, parity, bits, flow);
 663}
 664
 665static struct uart_driver amba_reg;
 666static struct console amba_console = {
 667        .name           = "ttyAM",
 668        .write          = pl010_console_write,
 669        .device         = uart_console_device,
 670        .setup          = pl010_console_setup,
 671        .flags          = CON_PRINTBUFFER,
 672        .index          = -1,
 673        .data           = &amba_reg,
 674};
 675
 676#define AMBA_CONSOLE    &amba_console
 677#else
 678#define AMBA_CONSOLE    NULL
 679#endif
 680
 681static DEFINE_MUTEX(amba_reg_lock);
 682static struct uart_driver amba_reg = {
 683        .owner                  = THIS_MODULE,
 684        .driver_name            = "ttyAM",
 685        .dev_name               = "ttyAM",
 686        .major                  = SERIAL_AMBA_MAJOR,
 687        .minor                  = SERIAL_AMBA_MINOR,
 688        .nr                     = UART_NR,
 689        .cons                   = AMBA_CONSOLE,
 690};
 691
 692static int pl010_probe(struct amba_device *dev, const struct amba_id *id)
 693{
 694        struct uart_amba_port *uap;
 695        void __iomem *base;
 696        int i, ret;
 697
 698        for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
 699                if (amba_ports[i] == NULL)
 700                        break;
 701
 702        if (i == ARRAY_SIZE(amba_ports))
 703                return -EBUSY;
 704
 705        uap = devm_kzalloc(&dev->dev, sizeof(struct uart_amba_port),
 706                           GFP_KERNEL);
 707        if (!uap)
 708                return -ENOMEM;
 709
 710        base = devm_ioremap(&dev->dev, dev->res.start,
 711                            resource_size(&dev->res));
 712        if (!base)
 713                return -ENOMEM;
 714
 715        uap->clk = devm_clk_get(&dev->dev, NULL);
 716        if (IS_ERR(uap->clk))
 717                return PTR_ERR(uap->clk);
 718
 719        uap->port.dev = &dev->dev;
 720        uap->port.mapbase = dev->res.start;
 721        uap->port.membase = base;
 722        uap->port.iotype = UPIO_MEM;
 723        uap->port.irq = dev->irq[0];
 724        uap->port.fifosize = 16;
 725        uap->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_AMBA_PL010_CONSOLE);
 726        uap->port.ops = &amba_pl010_pops;
 727        uap->port.flags = UPF_BOOT_AUTOCONF;
 728        uap->port.line = i;
 729        uap->dev = dev;
 730        uap->data = dev_get_platdata(&dev->dev);
 731
 732        amba_ports[i] = uap;
 733
 734        amba_set_drvdata(dev, uap);
 735
 736        mutex_lock(&amba_reg_lock);
 737        if (!amba_reg.state) {
 738                ret = uart_register_driver(&amba_reg);
 739                if (ret < 0) {
 740                        mutex_unlock(&amba_reg_lock);
 741                        dev_err(uap->port.dev,
 742                                "Failed to register AMBA-PL010 driver\n");
 743                        return ret;
 744                }
 745        }
 746        mutex_unlock(&amba_reg_lock);
 747
 748        ret = uart_add_one_port(&amba_reg, &uap->port);
 749        if (ret)
 750                amba_ports[i] = NULL;
 751
 752        return ret;
 753}
 754
 755static void pl010_remove(struct amba_device *dev)
 756{
 757        struct uart_amba_port *uap = amba_get_drvdata(dev);
 758        int i;
 759        bool busy = false;
 760
 761        uart_remove_one_port(&amba_reg, &uap->port);
 762
 763        for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
 764                if (amba_ports[i] == uap)
 765                        amba_ports[i] = NULL;
 766                else if (amba_ports[i])
 767                        busy = true;
 768
 769        if (!busy)
 770                uart_unregister_driver(&amba_reg);
 771}
 772
 773#ifdef CONFIG_PM_SLEEP
 774static int pl010_suspend(struct device *dev)
 775{
 776        struct uart_amba_port *uap = dev_get_drvdata(dev);
 777
 778        if (uap)
 779                uart_suspend_port(&amba_reg, &uap->port);
 780
 781        return 0;
 782}
 783
 784static int pl010_resume(struct device *dev)
 785{
 786        struct uart_amba_port *uap = dev_get_drvdata(dev);
 787
 788        if (uap)
 789                uart_resume_port(&amba_reg, &uap->port);
 790
 791        return 0;
 792}
 793#endif
 794
 795static SIMPLE_DEV_PM_OPS(pl010_dev_pm_ops, pl010_suspend, pl010_resume);
 796
 797static const struct amba_id pl010_ids[] = {
 798        {
 799                .id     = 0x00041010,
 800                .mask   = 0x000fffff,
 801        },
 802        { 0, 0 },
 803};
 804
 805MODULE_DEVICE_TABLE(amba, pl010_ids);
 806
 807static struct amba_driver pl010_driver = {
 808        .drv = {
 809                .name   = "uart-pl010",
 810                .pm     = &pl010_dev_pm_ops,
 811        },
 812        .id_table       = pl010_ids,
 813        .probe          = pl010_probe,
 814        .remove         = pl010_remove,
 815};
 816
 817static int __init pl010_init(void)
 818{
 819        printk(KERN_INFO "Serial: AMBA driver\n");
 820
 821        return  amba_driver_register(&pl010_driver);
 822}
 823
 824static void __exit pl010_exit(void)
 825{
 826        amba_driver_unregister(&pl010_driver);
 827}
 828
 829module_init(pl010_init);
 830module_exit(pl010_exit);
 831
 832MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
 833MODULE_DESCRIPTION("ARM AMBA serial port driver");
 834MODULE_LICENSE("GPL");
 835