/*
 *  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/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)
{
        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(&up->port.state->port);

        /* 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);
        }
}

/* should hold up->port.lock */
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;
        spin_lock(&up->port.lock);
        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);
        spin_unlock(&up->port.lock);
        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);
}

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 & (IGNBRK | 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 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_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(up->clk);

}

#ifdef CONFIG_CONSOLE_POLL
/*
 * Console polling routines for writing and reading from the uart while
 * in an interrupt or debug context.
 */

static int serial_pxa_get_poll_char(struct uart_port *port)
{
        struct uart_pxa_port *up = (struct uart_pxa_port *)port;
        unsigned char lsr = serial_in(up, UART_LSR);

        while (!(lsr & UART_LSR_DR))
                lsr = serial_in(up, UART_LSR);

        return serial_in(up, UART_RX);
}


static void serial_pxa_put_poll_char(struct uart_port *port,
                         unsigned char c)
{
        unsigned int ier;
        struct uart_pxa_port *up = (struct uart_pxa_port *)port;

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

        wait_for_xmitr(up);
        /*
         *      Send the character out.
         */
        serial_out(up, UART_TX, c);

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

#endif /* CONFIG_CONSOLE_POLL */

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

static const 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,
#if defined(CONFIG_CONSOLE_POLL) && defined(CONFIG_SERIAL_PXA_CONSOLE)
        .poll_get_char = serial_pxa_get_poll_char,
        .poll_put_char = serial_pxa_put_poll_char,
#endif
};

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 const struct of_device_id serial_pxa_dt_ids[] = {
        { .compatible = "mrvl,pxa-uart", },
        { .compatible = "mrvl,mmp-uart", },
        {}
};

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;
        }

        ret = clk_prepare(sport->clk);
        if (ret) {
                clk_put(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_unprepare(sport->clk);
        clk_put(sport->clk);
 err_free:
        kfree(sport);
        return ret;
}

static struct platform_driver serial_pxa_driver = {
        .probe          = serial_pxa_probe,

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


/* 8250 driver for PXA serial ports should be used */
static 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;
}
device_initcall(serial_pxa_init);