pxa.c

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/*
 *  Based on drivers/serial/8250.c by Russell King.
 *
 *  Author: Nicolas Pitre
 *  Created:    Feb 20, 2003
 *  Copyright:  (C) 2003 Monta Vista Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Note 1: This driver is made separate from the already too overloaded
 * 8250.c because it needs some kirks of its own and that'll make it
 * easier to add DMA support.
 *
 * Note 2: I'm too sick of device allocation policies for serial ports.
 * If someone else wants to request an "official" allocation of major/minor
 * for this driver please be my guest.  And don't forget that new hardware
 * to come from Intel might have more than 3 or 4 of those UARTs.  Let's
 * hope for a better port registration and dynamic device allocation scheme
 * with the serial core maintainer satisfaction to appear soon.
 */


#if defined(CONFIG_SERIAL_PXA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/serial_reg.h>
#include <linux/circ_buf.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/slab.h>

#define PXA_NAME_LEN        8

struct uart_pxa_port {
    struct uart_port        port;
    unsigned char           ier;
    unsigned char           lcr;
    unsigned char           mcr;
    unsigned int            lsr_break_flag;
    struct clk      *clk;
    char            name[PXA_NAME_LEN];
};

static inline unsigned int serial_in(struct uart_pxa_port *up, int offset)
{
    offset <<= 2;
    return readl(up->port.membase + offset);
}

static inline void serial_out(struct uart_pxa_port *up, int offset, int value)
{
    offset <<= 2;
    writel(value, up->port.membase + offset);
}

static void serial_pxa_enable_ms(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    up->ier |= UART_IER_MSI;
    serial_out(up, UART_IER, up->ier);
}

static void serial_pxa_stop_tx(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    if (up->ier & UART_IER_THRI) {
        up->ier &= ~UART_IER_THRI;
        serial_out(up, UART_IER, up->ier);
    }
}

static void serial_pxa_stop_rx(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    up->ier &= ~UART_IER_RLSI;
    up->port.read_status_mask &= ~UART_LSR_DR;
    serial_out(up, UART_IER, up->ier);
}

static inline void receive_chars(struct uart_pxa_port *up, int *status)
{
    struct tty_struct *tty = up->port.state->port.tty;
    unsigned int ch, flag;
    int max_count = 256;

    do {
        /* work around Errata #20 according to
         * Intel(R) PXA27x Processor Family
         * Specification Update (May 2005)
         *
         * Step 2
         * Disable the Reciever Time Out Interrupt via IER[RTOEI]
         */
        up->ier &= ~UART_IER_RTOIE;
        serial_out(up, UART_IER, up->ier);

        ch = serial_in(up, UART_RX);
        flag = TTY_NORMAL;
        up->port.icount.rx++;

        if (unlikely(*status & (UART_LSR_BI | UART_LSR_PE |
                       UART_LSR_FE | UART_LSR_OE))) {
            /*
             * For statistics only
             */
            if (*status & UART_LSR_BI) {
                *status &= ~(UART_LSR_FE | UART_LSR_PE);
                up->port.icount.brk++;
                /*
                 * We do the SysRQ and SAK checking
                 * here because otherwise the break
                 * may get masked by ignore_status_mask
                 * or read_status_mask.
                 */
                if (uart_handle_break(&up->port))
                    goto ignore_char;
            } else if (*status & UART_LSR_PE)
                up->port.icount.parity++;
            else if (*status & UART_LSR_FE)
                up->port.icount.frame++;
            if (*status & UART_LSR_OE)
                up->port.icount.overrun++;

            /*
             * Mask off conditions which should be ignored.
             */
            *status &= up->port.read_status_mask;

#ifdef CONFIG_SERIAL_PXA_CONSOLE
            if (up->port.line == up->port.cons->index) {
                /* Recover the break flag from console xmit */
                *status |= up->lsr_break_flag;
                up->lsr_break_flag = 0;
            }
#endif
            if (*status & UART_LSR_BI) {
                flag = TTY_BREAK;
            } else if (*status & UART_LSR_PE)
                flag = TTY_PARITY;
            else if (*status & UART_LSR_FE)
                flag = TTY_FRAME;
        }

        if (uart_handle_sysrq_char(&up->port, ch))
            goto ignore_char;

        uart_insert_char(&up->port, *status, UART_LSR_OE, ch, flag);

    ignore_char:
        *status = serial_in(up, UART_LSR);
    } while ((*status & UART_LSR_DR) && (max_count-- > 0));
    tty_flip_buffer_push(tty);

    /* work around Errata #20 according to
     * Intel(R) PXA27x Processor Family
     * Specification Update (May 2005)
     *
     * Step 6:
     * No more data in FIFO: Re-enable RTO interrupt via IER[RTOIE]
     */
    up->ier |= UART_IER_RTOIE;
    serial_out(up, UART_IER, up->ier);
}

static void transmit_chars(struct uart_pxa_port *up)
{
    struct circ_buf *xmit = &up->port.state->xmit;
    int count;

    if (up->port.x_char) {
        serial_out(up, UART_TX, up->port.x_char);
        up->port.icount.tx++;
        up->port.x_char = 0;
        return;
    }
    if (uart_circ_empty(xmit) || uart_tx_stopped(&up->port)) {
        serial_pxa_stop_tx(&up->port);
        return;
    }

    count = up->port.fifosize / 2;
    do {
        serial_out(up, UART_TX, xmit->buf[xmit->tail]);
        xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
        up->port.icount.tx++;
        if (uart_circ_empty(xmit))
            break;
    } while (--count > 0);

    if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
        uart_write_wakeup(&up->port);


    if (uart_circ_empty(xmit))
        serial_pxa_stop_tx(&up->port);
}

static void serial_pxa_start_tx(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    if (!(up->ier & UART_IER_THRI)) {
        up->ier |= UART_IER_THRI;
        serial_out(up, UART_IER, up->ier);
    }
}

static inline void check_modem_status(struct uart_pxa_port *up)
{
    int status;

    status = serial_in(up, UART_MSR);

    if ((status & UART_MSR_ANY_DELTA) == 0)
        return;

    if (status & UART_MSR_TERI)
        up->port.icount.rng++;
    if (status & UART_MSR_DDSR)
        up->port.icount.dsr++;
    if (status & UART_MSR_DDCD)
        uart_handle_dcd_change(&up->port, status & UART_MSR_DCD);
    if (status & UART_MSR_DCTS)
        uart_handle_cts_change(&up->port, status & UART_MSR_CTS);

    wake_up_interruptible(&up->port.state->port.delta_msr_wait);
}

/*
 * This handles the interrupt from one port.
 */
static inline irqreturn_t serial_pxa_irq(int irq, void *dev_id)
{
    struct uart_pxa_port *up = dev_id;
    unsigned int iir, lsr;

    iir = serial_in(up, UART_IIR);
    if (iir & UART_IIR_NO_INT)
        return IRQ_NONE;
    lsr = serial_in(up, UART_LSR);
    if (lsr & UART_LSR_DR)
        receive_chars(up, &lsr);
    check_modem_status(up);
    if (lsr & UART_LSR_THRE)
        transmit_chars(up);
    return IRQ_HANDLED;
}

static unsigned int serial_pxa_tx_empty(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned long flags;
    unsigned int ret;

    spin_lock_irqsave(&up->port.lock, flags);
    ret = serial_in(up, UART_LSR) & UART_LSR_TEMT ? TIOCSER_TEMT : 0;
    spin_unlock_irqrestore(&up->port.lock, flags);

    return ret;
}

static unsigned int serial_pxa_get_mctrl(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned char status;
    unsigned int ret;

    status = serial_in(up, UART_MSR);

    ret = 0;
    if (status & UART_MSR_DCD)
        ret |= TIOCM_CAR;
    if (status & UART_MSR_RI)
        ret |= TIOCM_RNG;
    if (status & UART_MSR_DSR)
        ret |= TIOCM_DSR;
    if (status & UART_MSR_CTS)
        ret |= TIOCM_CTS;
    return ret;
}

static void serial_pxa_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned char mcr = 0;

    if (mctrl & TIOCM_RTS)
        mcr |= UART_MCR_RTS;
    if (mctrl & TIOCM_DTR)
        mcr |= UART_MCR_DTR;
    if (mctrl & TIOCM_OUT1)
        mcr |= UART_MCR_OUT1;
    if (mctrl & TIOCM_OUT2)
        mcr |= UART_MCR_OUT2;
    if (mctrl & TIOCM_LOOP)
        mcr |= UART_MCR_LOOP;

    mcr |= up->mcr;

    serial_out(up, UART_MCR, mcr);
}

static void serial_pxa_break_ctl(struct uart_port *port, int break_state)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned long flags;

    spin_lock_irqsave(&up->port.lock, flags);
    if (break_state == -1)
        up->lcr |= UART_LCR_SBC;
    else
        up->lcr &= ~UART_LCR_SBC;
    serial_out(up, UART_LCR, up->lcr);
    spin_unlock_irqrestore(&up->port.lock, flags);
}

#if 0
static void serial_pxa_dma_init(struct pxa_uart *up)
{
    up->rxdma =
        pxa_request_dma(up->name, DMA_PRIO_LOW, pxa_receive_dma, up);
    if (up->rxdma < 0)
        goto out;
    up->txdma =
        pxa_request_dma(up->name, DMA_PRIO_LOW, pxa_transmit_dma, up);
    if (up->txdma < 0)
        goto err_txdma;
    up->dmadesc = kmalloc(4 * sizeof(pxa_dma_desc), GFP_KERNEL);
    if (!up->dmadesc)
        goto err_alloc;

    /* ... */
err_alloc:
    pxa_free_dma(up->txdma);
err_rxdma:
    pxa_free_dma(up->rxdma);
out:
    return;
}
#endif

static int serial_pxa_startup(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned long flags;
    int retval;

    if (port->line == 3) /* HWUART */
        up->mcr |= UART_MCR_AFE;
    else
        up->mcr = 0;

    up->port.uartclk = clk_get_rate(up->clk);

    /*
     * Allocate the IRQ
     */
    retval = request_irq(up->port.irq, serial_pxa_irq, 0, up->name, up);
    if (retval)
        return retval;

    /*
     * Clear the FIFO buffers and disable them.
     * (they will be reenabled in set_termios())
     */
    serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
    serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
            UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
    serial_out(up, UART_FCR, 0);

    /*
     * Clear the interrupt registers.
     */
    (void) serial_in(up, UART_LSR);
    (void) serial_in(up, UART_RX);
    (void) serial_in(up, UART_IIR);
    (void) serial_in(up, UART_MSR);

    /*
     * Now, initialize the UART
     */
    serial_out(up, UART_LCR, UART_LCR_WLEN8);

    spin_lock_irqsave(&up->port.lock, flags);
    up->port.mctrl |= TIOCM_OUT2;
    serial_pxa_set_mctrl(&up->port, up->port.mctrl);
    spin_unlock_irqrestore(&up->port.lock, flags);

    /*
     * Finally, enable interrupts.  Note: Modem status interrupts
     * are set via set_termios(), which will be occurring imminently
     * anyway, so we don't enable them here.
     */
    up->ier = UART_IER_RLSI | UART_IER_RDI | UART_IER_RTOIE | UART_IER_UUE;
    serial_out(up, UART_IER, up->ier);

    /*
     * And clear the interrupt registers again for luck.
     */
    (void) serial_in(up, UART_LSR);
    (void) serial_in(up, UART_RX);
    (void) serial_in(up, UART_IIR);
    (void) serial_in(up, UART_MSR);

    return 0;
}

static void serial_pxa_shutdown(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned long flags;

    free_irq(up->port.irq, up);

    /*
     * Disable interrupts from this port
     */
    up->ier = 0;
    serial_out(up, UART_IER, 0);

    spin_lock_irqsave(&up->port.lock, flags);
    up->port.mctrl &= ~TIOCM_OUT2;
    serial_pxa_set_mctrl(&up->port, up->port.mctrl);
    spin_unlock_irqrestore(&up->port.lock, flags);

    /*
     * Disable break condition and FIFOs
     */
    serial_out(up, UART_LCR, serial_in(up, UART_LCR) & ~UART_LCR_SBC);
    serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                  UART_FCR_CLEAR_RCVR |
                  UART_FCR_CLEAR_XMIT);
    serial_out(up, UART_FCR, 0);
}

static void
serial_pxa_set_termios(struct uart_port *port, struct ktermios *termios,
               struct ktermios *old)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    unsigned char cval, fcr = 0;
    unsigned long flags;
    unsigned int baud, quot;
    unsigned int dll;

    switch (termios->c_cflag & CSIZE) {
    case CS5:
        cval = UART_LCR_WLEN5;
        break;
    case CS6:
        cval = UART_LCR_WLEN6;
        break;
    case CS7:
        cval = UART_LCR_WLEN7;
        break;
    default:
    case CS8:
        cval = UART_LCR_WLEN8;
        break;
    }

    if (termios->c_cflag & CSTOPB)
        cval |= UART_LCR_STOP;
    if (termios->c_cflag & PARENB)
        cval |= UART_LCR_PARITY;
    if (!(termios->c_cflag & PARODD))
        cval |= UART_LCR_EPAR;

    /*
     * Ask the core to calculate the divisor for us.
     */
    baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);
    quot = uart_get_divisor(port, baud);

    if ((up->port.uartclk / quot) < (2400 * 16))
        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR1;
    else if ((up->port.uartclk / quot) < (230400 * 16))
        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR8;
    else
        fcr = UART_FCR_ENABLE_FIFO | UART_FCR_PXAR32;

    /*
     * Ok, we're now changing the port state.  Do it with
     * interrupts disabled.
     */
    spin_lock_irqsave(&up->port.lock, flags);

    /*
     * Ensure the port will be enabled.
     * This is required especially for serial console.
     */
    up->ier |= UART_IER_UUE;

    /*
     * Update the per-port timeout.
     */
    uart_update_timeout(port, termios->c_cflag, baud);

    up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR;
    if (termios->c_iflag & INPCK)
        up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE;
    if (termios->c_iflag & (BRKINT | PARMRK))
        up->port.read_status_mask |= UART_LSR_BI;

    /*
     * Characters to ignore
     */
    up->port.ignore_status_mask = 0;
    if (termios->c_iflag & IGNPAR)
        up->port.ignore_status_mask |= UART_LSR_PE | UART_LSR_FE;
    if (termios->c_iflag & IGNBRK) {
        up->port.ignore_status_mask |= UART_LSR_BI;
        /*
         * If we're ignoring parity and break indicators,
         * ignore overruns too (for real raw support).
         */
        if (termios->c_iflag & IGNPAR)
            up->port.ignore_status_mask |= UART_LSR_OE;
    }

    /*
     * ignore all characters if CREAD is not set
     */
    if ((termios->c_cflag & CREAD) == 0)
        up->port.ignore_status_mask |= UART_LSR_DR;

    /*
     * CTS flow control flag and modem status interrupts
     */
    up->ier &= ~UART_IER_MSI;
    if (UART_ENABLE_MS(&up->port, termios->c_cflag))
        up->ier |= UART_IER_MSI;

    serial_out(up, UART_IER, up->ier);

    if (termios->c_cflag & CRTSCTS)
        up->mcr |= UART_MCR_AFE;
    else
        up->mcr &= ~UART_MCR_AFE;

    serial_out(up, UART_LCR, cval | UART_LCR_DLAB); /* set DLAB */
    serial_out(up, UART_DLL, quot & 0xff);      /* LS of divisor */

    /*
     * work around Errata #75 according to Intel(R) PXA27x Processor Family
     * Specification Update (Nov 2005)
     */
    dll = serial_in(up, UART_DLL);
    WARN_ON(dll != (quot & 0xff));

    serial_out(up, UART_DLM, quot >> 8);        /* MS of divisor */
    serial_out(up, UART_LCR, cval);         /* reset DLAB */
    up->lcr = cval;                 /* Save LCR */
    serial_pxa_set_mctrl(&up->port, up->port.mctrl);
    serial_out(up, UART_FCR, fcr);
    spin_unlock_irqrestore(&up->port.lock, flags);
}

static void
serial_pxa_pm(struct uart_port *port, unsigned int state,
          unsigned int oldstate)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    if (!state)
        clk_prepare_enable(up->clk);
    else
        clk_disable_unprepare(up->clk);
}

static void serial_pxa_release_port(struct uart_port *port)
{
}

static int serial_pxa_request_port(struct uart_port *port)
{
    return 0;
}

static void serial_pxa_config_port(struct uart_port *port, int flags)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    up->port.type = PORT_PXA;
}

static int
serial_pxa_verify_port(struct uart_port *port, struct serial_struct *ser)
{
    /* we don't want the core code to modify any port params */
    return -EINVAL;
}

static const char *
serial_pxa_type(struct uart_port *port)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;
    return up->name;
}

static struct uart_pxa_port *serial_pxa_ports[4];
static struct uart_driver serial_pxa_reg;

#ifdef CONFIG_SERIAL_PXA_CONSOLE

#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

/*
 *  Wait for transmitter & holding register to empty
 */
static inline void wait_for_xmitr(struct uart_pxa_port *up)
{
    unsigned int status, tmout = 10000;

    /* Wait up to 10ms for the character(s) to be sent. */
    do {
        status = serial_in(up, UART_LSR);

        if (status & UART_LSR_BI)
            up->lsr_break_flag = UART_LSR_BI;

        if (--tmout == 0)
            break;
        udelay(1);
    } while ((status & BOTH_EMPTY) != BOTH_EMPTY);

    /* Wait up to 1s for flow control if necessary */
    if (up->port.flags & UPF_CONS_FLOW) {
        tmout = 1000000;
        while (--tmout &&
               ((serial_in(up, UART_MSR) & UART_MSR_CTS) == 0))
            udelay(1);
    }
}

static void serial_pxa_console_putchar(struct uart_port *port, int ch)
{
    struct uart_pxa_port *up = (struct uart_pxa_port *)port;

    wait_for_xmitr(up);
    serial_out(up, UART_TX, ch);
}

/*
 * Print a string to the serial port trying not to disturb
 * any possible real use of the port...
 *
 *  The console_lock must be held when we get here.
 */
static void
serial_pxa_console_write(struct console *co, const char *s, unsigned int count)
{
    struct uart_pxa_port *up = serial_pxa_ports[co->index];
    unsigned int ier;
    unsigned long flags;
    int locked = 1;

    clk_prepare_enable(up->clk);

    local_irq_save(flags);
    if (up->port.sysrq)
        locked = 0;
    else if (oops_in_progress)
        locked = spin_trylock(&up->port.lock);
    else
        spin_lock(&up->port.lock);

    /*
     *  First save the IER then disable the interrupts
     */
    ier = serial_in(up, UART_IER);
    serial_out(up, UART_IER, UART_IER_UUE);

    uart_console_write(&up->port, s, count, serial_pxa_console_putchar);

    /*
     *  Finally, wait for transmitter to become empty
     *  and restore the IER
     */
    wait_for_xmitr(up);
    serial_out(up, UART_IER, ier);

    if (locked)
        spin_unlock(&up->port.lock);
    local_irq_restore(flags);

    clk_disable_unprepare(up->clk);
}

static int __init
serial_pxa_console_setup(struct console *co, char *options)
{
    struct uart_pxa_port *up;
    int baud = 9600;
    int bits = 8;
    int parity = 'n';
    int flow = 'n';

    if (co->index == -1 || co->index >= serial_pxa_reg.nr)
        co->index = 0;
    up = serial_pxa_ports[co->index];
    if (!up)
        return -ENODEV;

    if (options)
        uart_parse_options(options, &baud, &parity, &bits, &flow);

    return uart_set_options(&up->port, co, baud, parity, bits, flow);
}

static struct console serial_pxa_console = {
    .name       = "ttyS",
    .write      = serial_pxa_console_write,
    .device     = uart_console_device,
    .setup      = serial_pxa_console_setup,
    .flags      = CON_PRINTBUFFER,
    .index      = -1,
    .data       = &serial_pxa_reg,
};

#define PXA_CONSOLE &serial_pxa_console
#else
#define PXA_CONSOLE NULL
#endif

struct uart_ops serial_pxa_pops = {
    .tx_empty   = serial_pxa_tx_empty,
    .set_mctrl  = serial_pxa_set_mctrl,
    .get_mctrl  = serial_pxa_get_mctrl,
    .stop_tx    = serial_pxa_stop_tx,
    .start_tx   = serial_pxa_start_tx,
    .stop_rx    = serial_pxa_stop_rx,
    .enable_ms  = serial_pxa_enable_ms,
    .break_ctl  = serial_pxa_break_ctl,
    .startup    = serial_pxa_startup,
    .shutdown   = serial_pxa_shutdown,
    .set_termios    = serial_pxa_set_termios,
    .pm     = serial_pxa_pm,
    .type       = serial_pxa_type,
    .release_port   = serial_pxa_release_port,
    .request_port   = serial_pxa_request_port,
    .config_port    = serial_pxa_config_port,
    .verify_port    = serial_pxa_verify_port,
};

static struct uart_driver serial_pxa_reg = {
    .owner      = THIS_MODULE,
    .driver_name    = "PXA serial",
    .dev_name   = "ttyS",
    .major      = TTY_MAJOR,
    .minor      = 64,
    .nr     = 4,
    .cons       = PXA_CONSOLE,
};

#ifdef CONFIG_PM
static int serial_pxa_suspend(struct device *dev)
{
        struct uart_pxa_port *sport = dev_get_drvdata(dev);

        if (sport)
                uart_suspend_port(&serial_pxa_reg, &sport->port);

        return 0;
}

static int serial_pxa_resume(struct device *dev)
{
        struct uart_pxa_port *sport = dev_get_drvdata(dev);

        if (sport)
                uart_resume_port(&serial_pxa_reg, &sport->port);

        return 0;
}

static const struct dev_pm_ops serial_pxa_pm_ops = {
    .suspend    = serial_pxa_suspend,
    .resume     = serial_pxa_resume,
};
#endif

static struct of_device_id serial_pxa_dt_ids[] = {
    { .compatible = "mrvl,pxa-uart", },
    { .compatible = "mrvl,mmp-uart", },
    {}
};
MODULE_DEVICE_TABLE(of, serial_pxa_dt_ids);

static int serial_pxa_probe_dt(struct platform_device *pdev,
                   struct uart_pxa_port *sport)
{
    struct device_node *np = pdev->dev.of_node;
    int ret;

    if (!np)
        return 1;

    ret = of_alias_get_id(np, "serial");
    if (ret < 0) {
        dev_err(&pdev->dev, "failed to get alias id, errno %d\n", ret);
        return ret;
    }
    sport->port.line = ret;
    return 0;
}

static int serial_pxa_probe(struct platform_device *dev)
{
    struct uart_pxa_port *sport;
    struct resource *mmres, *irqres;
    int ret;

    mmres = platform_get_resource(dev, IORESOURCE_MEM, 0);
    irqres = platform_get_resource(dev, IORESOURCE_IRQ, 0);
    if (!mmres || !irqres)
        return -ENODEV;

    sport = kzalloc(sizeof(struct uart_pxa_port), GFP_KERNEL);
    if (!sport)
        return -ENOMEM;

    sport->clk = clk_get(&dev->dev, NULL);
    if (IS_ERR(sport->clk)) {
        ret = PTR_ERR(sport->clk);
        goto err_free;
    }

    sport->port.type = PORT_PXA;
    sport->port.iotype = UPIO_MEM;
    sport->port.mapbase = mmres->start;
    sport->port.irq = irqres->start;
    sport->port.fifosize = 64;
    sport->port.ops = &serial_pxa_pops;
    sport->port.dev = &dev->dev;
    sport->port.flags = UPF_IOREMAP | UPF_BOOT_AUTOCONF;
    sport->port.uartclk = clk_get_rate(sport->clk);

    ret = serial_pxa_probe_dt(dev, sport);
    if (ret > 0)
        sport->port.line = dev->id;
    else if (ret < 0)
        goto err_clk;
    snprintf(sport->name, PXA_NAME_LEN - 1, "UART%d", sport->port.line + 1);

    sport->port.membase = ioremap(mmres->start, resource_size(mmres));
    if (!sport->port.membase) {
        ret = -ENOMEM;
        goto err_clk;
    }

    serial_pxa_ports[sport->port.line] = sport;

    uart_add_one_port(&serial_pxa_reg, &sport->port);
    platform_set_drvdata(dev, sport);

    return 0;

 err_clk:
    clk_put(sport->clk);
 err_free:
    kfree(sport);
    return ret;
}

static int serial_pxa_remove(struct platform_device *dev)
{
    struct uart_pxa_port *sport = platform_get_drvdata(dev);

    platform_set_drvdata(dev, NULL);

    uart_remove_one_port(&serial_pxa_reg, &sport->port);
    clk_put(sport->clk);
    kfree(sport);

    return 0;
}

static struct platform_driver serial_pxa_driver = {
        .probe          = serial_pxa_probe,
        .remove         = serial_pxa_remove,

    .driver     = {
            .name   = "pxa2xx-uart",
        .owner  = THIS_MODULE,
#ifdef CONFIG_PM
        .pm = &serial_pxa_pm_ops,
#endif
        .of_match_table = serial_pxa_dt_ids,
    },
};

int __init serial_pxa_init(void)
{
    int ret;

    ret = uart_register_driver(&serial_pxa_reg);
    if (ret != 0)
        return ret;

    ret = platform_driver_register(&serial_pxa_driver);
    if (ret != 0)
        uart_unregister_driver(&serial_pxa_reg);

    return ret;
}

void __exit serial_pxa_exit(void)
{
    platform_driver_unregister(&serial_pxa_driver);
    uart_unregister_driver(&serial_pxa_reg);
}

module_init(serial_pxa_init);
module_exit(serial_pxa_exit);

MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pxa2xx-uart");