// SPDX-License-Identifier: GPL-2.0+
/*
 *  Driver for SA11x0 serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
 */

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/platform_data/sa11x0-serial.h>
#include <linux/platform_device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/io.h>

#include <asm/irq.h>
#include <mach/hardware.h>
#include <mach/irqs.h>

#include "serial_mctrl_gpio.h"

/* We've been assigned a range on the "Low-density serial ports" major */
#define SERIAL_SA1100_MAJOR     204
#define MINOR_START             5

#define NR_PORTS                3

#define SA1100_ISR_PASS_LIMIT   256

/*
 * Convert from ignore_status_mask or read_status_mask to UTSR[01]
 */
#define SM_TO_UTSR0(x)  ((x) & 0xff)
#define SM_TO_UTSR1(x)  ((x) >> 8)
#define UTSR0_TO_SM(x)  ((x))
#define UTSR1_TO_SM(x)  ((x) << 8)

#define UART_GET_UTCR0(sport)   __raw_readl((sport)->port.membase + UTCR0)
#define UART_GET_UTCR1(sport)   __raw_readl((sport)->port.membase + UTCR1)
#define UART_GET_UTCR2(sport)   __raw_readl((sport)->port.membase + UTCR2)
#define UART_GET_UTCR3(sport)   __raw_readl((sport)->port.membase + UTCR3)
#define UART_GET_UTSR0(sport)   __raw_readl((sport)->port.membase + UTSR0)
#define UART_GET_UTSR1(sport)   __raw_readl((sport)->port.membase + UTSR1)
#define UART_GET_CHAR(sport)    __raw_readl((sport)->port.membase + UTDR)

#define UART_PUT_UTCR0(sport,v) __raw_writel((v),(sport)->port.membase + UTCR0)
#define UART_PUT_UTCR1(sport,v) __raw_writel((v),(sport)->port.membase + UTCR1)
#define UART_PUT_UTCR2(sport,v) __raw_writel((v),(sport)->port.membase + UTCR2)
#define UART_PUT_UTCR3(sport,v) __raw_writel((v),(sport)->port.membase + UTCR3)
#define UART_PUT_UTSR0(sport,v) __raw_writel((v),(sport)->port.membase + UTSR0)
#define UART_PUT_UTSR1(sport,v) __raw_writel((v),(sport)->port.membase + UTSR1)
#define UART_PUT_CHAR(sport,v)  __raw_writel((v),(sport)->port.membase + UTDR)

/*
 * This is the size of our serial port register set.
 */
#define UART_PORT_SIZE  0x24

/*
 * This determines how often we check the modem status signals
 * for any change.  They generally aren't connected to an IRQ
 * so we have to poll them.  We also check immediately before
 * filling the TX fifo incase CTS has been dropped.
 */
#define MCTRL_TIMEOUT   (250*HZ/1000)

struct sa1100_port {
        struct uart_port        port;
        struct timer_list       timer;
        unsigned int            old_status;
        struct mctrl_gpios      *gpios;
};

/*
 * Handle any change of modem status signal since we were last called.
 */
static void sa1100_mctrl_check(struct sa1100_port *sport)
{
        unsigned int status, changed;

        status = sport->port.ops->get_mctrl(&sport->port);
        changed = status ^ sport->old_status;

        if (changed == 0)
                return;

        sport->old_status = status;

        if (changed & TIOCM_RI)
                sport->port.icount.rng++;
        if (changed & TIOCM_DSR)
                sport->port.icount.dsr++;
        if (changed & TIOCM_CAR)
                uart_handle_dcd_change(&sport->port, status & TIOCM_CAR);
        if (changed & TIOCM_CTS)
                uart_handle_cts_change(&sport->port, status & TIOCM_CTS);

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

/*
 * This is our per-port timeout handler, for checking the
 * modem status signals.
 */
static void sa1100_timeout(struct timer_list *t)
{
        struct sa1100_port *sport = from_timer(sport, t, timer);
        unsigned long flags;

        if (sport->port.state) {
                spin_lock_irqsave(&sport->port.lock, flags);
                sa1100_mctrl_check(sport);
                spin_unlock_irqrestore(&sport->port.lock, flags);

                mod_timer(&sport->timer, jiffies + MCTRL_TIMEOUT);
        }
}

/*
 * interrupts disabled on entry
 */
static void sa1100_stop_tx(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        u32 utcr3;

        utcr3 = UART_GET_UTCR3(sport);
        UART_PUT_UTCR3(sport, utcr3 & ~UTCR3_TIE);
        sport->port.read_status_mask &= ~UTSR0_TO_SM(UTSR0_TFS);
}

/*
 * port locked and interrupts disabled
 */
static void sa1100_start_tx(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        u32 utcr3;

        utcr3 = UART_GET_UTCR3(sport);
        sport->port.read_status_mask |= UTSR0_TO_SM(UTSR0_TFS);
        UART_PUT_UTCR3(sport, utcr3 | UTCR3_TIE);
}

/*
 * Interrupts enabled
 */
static void sa1100_stop_rx(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        u32 utcr3;

        utcr3 = UART_GET_UTCR3(sport);
        UART_PUT_UTCR3(sport, utcr3 & ~UTCR3_RIE);
}

/*
 * Set the modem control timer to fire immediately.
 */
static void sa1100_enable_ms(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        mod_timer(&sport->timer, jiffies);

        mctrl_gpio_enable_ms(sport->gpios);
}

static void
sa1100_rx_chars(struct sa1100_port *sport)
{
        unsigned int status, ch, flg;

        status = UTSR1_TO_SM(UART_GET_UTSR1(sport)) |
                 UTSR0_TO_SM(UART_GET_UTSR0(sport));
        while (status & UTSR1_TO_SM(UTSR1_RNE)) {
                ch = UART_GET_CHAR(sport);

                sport->port.icount.rx++;

                flg = TTY_NORMAL;

                /*
                 * note that the error handling code is
                 * out of the main execution path
                 */
                if (status & UTSR1_TO_SM(UTSR1_PRE | UTSR1_FRE | UTSR1_ROR)) {
                        if (status & UTSR1_TO_SM(UTSR1_PRE))
                                sport->port.icount.parity++;
                        else if (status & UTSR1_TO_SM(UTSR1_FRE))
                                sport->port.icount.frame++;
                        if (status & UTSR1_TO_SM(UTSR1_ROR))
                                sport->port.icount.overrun++;

                        status &= sport->port.read_status_mask;

                        if (status & UTSR1_TO_SM(UTSR1_PRE))
                                flg = TTY_PARITY;
                        else if (status & UTSR1_TO_SM(UTSR1_FRE))
                                flg = TTY_FRAME;

                        sport->port.sysrq = 0;
                }

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

                uart_insert_char(&sport->port, status, UTSR1_TO_SM(UTSR1_ROR), ch, flg);

        ignore_char:
                status = UTSR1_TO_SM(UART_GET_UTSR1(sport)) |
                         UTSR0_TO_SM(UART_GET_UTSR0(sport));
        }

        tty_flip_buffer_push(&sport->port.state->port);
}

static void sa1100_tx_chars(struct sa1100_port *sport)
{
        struct circ_buf *xmit = &sport->port.state->xmit;

        if (sport->port.x_char) {
                UART_PUT_CHAR(sport, sport->port.x_char);
                sport->port.icount.tx++;
                sport->port.x_char = 0;
                return;
        }

        /*
         * Check the modem control lines before
         * transmitting anything.
         */
        sa1100_mctrl_check(sport);

        if (uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)) {
                sa1100_stop_tx(&sport->port);
                return;
        }

        /*
         * Tried using FIFO (not checking TNF) for fifo fill:
         * still had the '4 bytes repeated' problem.
         */
        while (UART_GET_UTSR1(sport) & UTSR1_TNF) {
                UART_PUT_CHAR(sport, xmit->buf[xmit->tail]);
                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                sport->port.icount.tx++;
                if (uart_circ_empty(xmit))
                        break;
        }

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

        if (uart_circ_empty(xmit))
                sa1100_stop_tx(&sport->port);
}

static irqreturn_t sa1100_int(int irq, void *dev_id)
{
        struct sa1100_port *sport = dev_id;
        unsigned int status, pass_counter = 0;

        spin_lock(&sport->port.lock);
        status = UART_GET_UTSR0(sport);
        status &= SM_TO_UTSR0(sport->port.read_status_mask) | ~UTSR0_TFS;
        do {
                if (status & (UTSR0_RFS | UTSR0_RID)) {
                        /* Clear the receiver idle bit, if set */
                        if (status & UTSR0_RID)
                                UART_PUT_UTSR0(sport, UTSR0_RID);
                        sa1100_rx_chars(sport);
                }

                /* Clear the relevant break bits */
                if (status & (UTSR0_RBB | UTSR0_REB))
                        UART_PUT_UTSR0(sport, status & (UTSR0_RBB | UTSR0_REB));

                if (status & UTSR0_RBB)
                        sport->port.icount.brk++;

                if (status & UTSR0_REB)
                        uart_handle_break(&sport->port);

                if (status & UTSR0_TFS)
                        sa1100_tx_chars(sport);
                if (pass_counter++ > SA1100_ISR_PASS_LIMIT)
                        break;
                status = UART_GET_UTSR0(sport);
                status &= SM_TO_UTSR0(sport->port.read_status_mask) |
                          ~UTSR0_TFS;
        } while (status & (UTSR0_TFS | UTSR0_RFS | UTSR0_RID));
        spin_unlock(&sport->port.lock);

        return IRQ_HANDLED;
}

/*
 * Return TIOCSER_TEMT when transmitter is not busy.
 */
static unsigned int sa1100_tx_empty(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        return UART_GET_UTSR1(sport) & UTSR1_TBY ? 0 : TIOCSER_TEMT;
}

static unsigned int sa1100_get_mctrl(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        int ret = TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;

        mctrl_gpio_get(sport->gpios, &ret);

        return ret;
}

static void sa1100_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        mctrl_gpio_set(sport->gpios, mctrl);
}

/*
 * Interrupts always disabled.
 */
static void sa1100_break_ctl(struct uart_port *port, int break_state)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        unsigned long flags;
        unsigned int utcr3;

        spin_lock_irqsave(&sport->port.lock, flags);
        utcr3 = UART_GET_UTCR3(sport);
        if (break_state == -1)
                utcr3 |= UTCR3_BRK;
        else
                utcr3 &= ~UTCR3_BRK;
        UART_PUT_UTCR3(sport, utcr3);
        spin_unlock_irqrestore(&sport->port.lock, flags);
}

static int sa1100_startup(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        int retval;

        /*
         * Allocate the IRQ
         */
        retval = request_irq(sport->port.irq, sa1100_int, 0,
                             "sa11x0-uart", sport);
        if (retval)
                return retval;

        /*
         * Finally, clear and enable interrupts
         */
        UART_PUT_UTSR0(sport, -1);
        UART_PUT_UTCR3(sport, UTCR3_RXE | UTCR3_TXE | UTCR3_RIE);

        /*
         * Enable modem status interrupts
         */
        spin_lock_irq(&sport->port.lock);
        sa1100_enable_ms(&sport->port);
        spin_unlock_irq(&sport->port.lock);

        return 0;
}

static void sa1100_shutdown(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        /*
         * Stop our timer.
         */
        del_timer_sync(&sport->timer);

        /*
         * Free the interrupt
         */
        free_irq(sport->port.irq, sport);

        /*
         * Disable all interrupts, port and break condition.
         */
        UART_PUT_UTCR3(sport, 0);
}

static void
sa1100_set_termios(struct uart_port *port, struct ktermios *termios,
                   struct ktermios *old)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        unsigned long flags;
        unsigned int utcr0, old_utcr3, baud, quot;
        unsigned int old_csize = old ? old->c_cflag & CSIZE : CS8;

        /*
         * We only support CS7 and CS8.
         */
        while ((termios->c_cflag & CSIZE) != CS7 &&
               (termios->c_cflag & CSIZE) != CS8) {
                termios->c_cflag &= ~CSIZE;
                termios->c_cflag |= old_csize;
                old_csize = CS8;
        }

        if ((termios->c_cflag & CSIZE) == CS8)
                utcr0 = UTCR0_DSS;
        else
                utcr0 = 0;

        if (termios->c_cflag & CSTOPB)
                utcr0 |= UTCR0_SBS;
        if (termios->c_cflag & PARENB) {
                utcr0 |= UTCR0_PE;
                if (!(termios->c_cflag & PARODD))
                        utcr0 |= UTCR0_OES;
        }

        /*
         * 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);

        spin_lock_irqsave(&sport->port.lock, flags);

        sport->port.read_status_mask &= UTSR0_TO_SM(UTSR0_TFS);
        sport->port.read_status_mask |= UTSR1_TO_SM(UTSR1_ROR);
        if (termios->c_iflag & INPCK)
                sport->port.read_status_mask |=
                                UTSR1_TO_SM(UTSR1_FRE | UTSR1_PRE);
        if (termios->c_iflag & (BRKINT | PARMRK))
                sport->port.read_status_mask |=
                                UTSR0_TO_SM(UTSR0_RBB | UTSR0_REB);

        /*
         * Characters to ignore
         */
        sport->port.ignore_status_mask = 0;
        if (termios->c_iflag & IGNPAR)
                sport->port.ignore_status_mask |=
                                UTSR1_TO_SM(UTSR1_FRE | UTSR1_PRE);
        if (termios->c_iflag & IGNBRK) {
                sport->port.ignore_status_mask |=
                                UTSR0_TO_SM(UTSR0_RBB | UTSR0_REB);
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns too (for real raw support).
                 */
                if (termios->c_iflag & IGNPAR)
                        sport->port.ignore_status_mask |=
                                UTSR1_TO_SM(UTSR1_ROR);
        }

        del_timer_sync(&sport->timer);

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

        /*
         * disable interrupts and drain transmitter
         */
        old_utcr3 = UART_GET_UTCR3(sport);
        UART_PUT_UTCR3(sport, old_utcr3 & ~(UTCR3_RIE | UTCR3_TIE));

        while (UART_GET_UTSR1(sport) & UTSR1_TBY)
                barrier();

        /* then, disable everything */
        UART_PUT_UTCR3(sport, 0);

        /* set the parity, stop bits and data size */
        UART_PUT_UTCR0(sport, utcr0);

        /* set the baud rate */
        quot -= 1;
        UART_PUT_UTCR1(sport, ((quot & 0xf00) >> 8));
        UART_PUT_UTCR2(sport, (quot & 0xff));

        UART_PUT_UTSR0(sport, -1);

        UART_PUT_UTCR3(sport, old_utcr3);

        if (UART_ENABLE_MS(&sport->port, termios->c_cflag))
                sa1100_enable_ms(&sport->port);

        spin_unlock_irqrestore(&sport->port.lock, flags);
}

static const char *sa1100_type(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        return sport->port.type == PORT_SA1100 ? "SA1100" : NULL;
}

/*
 * Release the memory region(s) being used by 'port'.
 */
static void sa1100_release_port(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        release_mem_region(sport->port.mapbase, UART_PORT_SIZE);
}

/*
 * Request the memory region(s) being used by 'port'.
 */
static int sa1100_request_port(struct uart_port *port)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        return request_mem_region(sport->port.mapbase, UART_PORT_SIZE,
                        "sa11x0-uart") != NULL ? 0 : -EBUSY;
}

/*
 * Configure/autoconfigure the port.
 */
static void sa1100_config_port(struct uart_port *port, int flags)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        if (flags & UART_CONFIG_TYPE &&
            sa1100_request_port(&sport->port) == 0)
                sport->port.type = PORT_SA1100;
}

/*
 * Verify the new serial_struct (for TIOCSSERIAL).
 * The only change we allow are to the flags and type, and
 * even then only between PORT_SA1100 and PORT_UNKNOWN
 */
static int
sa1100_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);
        int ret = 0;

        if (ser->type != PORT_UNKNOWN && ser->type != PORT_SA1100)
                ret = -EINVAL;
        if (sport->port.irq != ser->irq)
                ret = -EINVAL;
        if (ser->io_type != SERIAL_IO_MEM)
                ret = -EINVAL;
        if (sport->port.uartclk / 16 != ser->baud_base)
                ret = -EINVAL;
        if ((void *)sport->port.mapbase != ser->iomem_base)
                ret = -EINVAL;
        if (sport->port.iobase != ser->port)
                ret = -EINVAL;
        if (ser->hub6 != 0)
                ret = -EINVAL;
        return ret;
}

static struct uart_ops sa1100_pops = {
        .tx_empty       = sa1100_tx_empty,
        .set_mctrl      = sa1100_set_mctrl,
        .get_mctrl      = sa1100_get_mctrl,
        .stop_tx        = sa1100_stop_tx,
        .start_tx       = sa1100_start_tx,
        .stop_rx        = sa1100_stop_rx,
        .enable_ms      = sa1100_enable_ms,
        .break_ctl      = sa1100_break_ctl,
        .startup        = sa1100_startup,
        .shutdown       = sa1100_shutdown,
        .set_termios    = sa1100_set_termios,
        .type           = sa1100_type,
        .release_port   = sa1100_release_port,
        .request_port   = sa1100_request_port,
        .config_port    = sa1100_config_port,
        .verify_port    = sa1100_verify_port,
};

static struct sa1100_port sa1100_ports[NR_PORTS];

/*
 * Setup the SA1100 serial ports.  Note that we don't include the IrDA
 * port here since we have our own SIR/FIR driver (see drivers/net/irda)
 *
 * Note also that we support "console=ttySAx" where "x" is either 0 or 1.
 * Which serial port this ends up being depends on the machine you're
 * running this kernel on.  I'm not convinced that this is a good idea,
 * but that's the way it traditionally works.
 *
 * Note that NanoEngine UART3 becomes UART2, and UART2 is no longer
 * used here.
 */
static void __init sa1100_init_ports(void)
{
        static int first = 1;
        int i;

        if (!first)
                return;
        first = 0;

        for (i = 0; i < NR_PORTS; i++) {
                sa1100_ports[i].port.uartclk   = 3686400;
                sa1100_ports[i].port.ops       = &sa1100_pops;
                sa1100_ports[i].port.fifosize  = 8;
                sa1100_ports[i].port.line      = i;
                sa1100_ports[i].port.iotype    = UPIO_MEM;
                timer_setup(&sa1100_ports[i].timer, sa1100_timeout, 0);
        }

        /*
         * make transmit lines outputs, so that when the port
         * is closed, the output is in the MARK state.
         */
        PPDR |= PPC_TXD1 | PPC_TXD3;
        PPSR |= PPC_TXD1 | PPC_TXD3;
}

void sa1100_register_uart_fns(struct sa1100_port_fns *fns)
{
        if (fns->get_mctrl)
                sa1100_pops.get_mctrl = fns->get_mctrl;
        if (fns->set_mctrl)
                sa1100_pops.set_mctrl = fns->set_mctrl;

        sa1100_pops.pm       = fns->pm;
        /*
         * FIXME: fns->set_wake is unused - this should be called from
         * the suspend() callback if device_may_wakeup(dev)) is set.
         */
}

void __init sa1100_register_uart(int idx, int port)
{
        if (idx >= NR_PORTS) {
                printk(KERN_ERR "%s: bad index number %d\n", __func__, idx);
                return;
        }

        switch (port) {
        case 1:
                sa1100_ports[idx].port.membase = (void __iomem *)&Ser1UTCR0;
                sa1100_ports[idx].port.mapbase = _Ser1UTCR0;
                sa1100_ports[idx].port.irq     = IRQ_Ser1UART;
                sa1100_ports[idx].port.flags   = UPF_BOOT_AUTOCONF;
                break;

        case 2:
                sa1100_ports[idx].port.membase = (void __iomem *)&Ser2UTCR0;
                sa1100_ports[idx].port.mapbase = _Ser2UTCR0;
                sa1100_ports[idx].port.irq     = IRQ_Ser2ICP;
                sa1100_ports[idx].port.flags   = UPF_BOOT_AUTOCONF;
                break;

        case 3:
                sa1100_ports[idx].port.membase = (void __iomem *)&Ser3UTCR0;
                sa1100_ports[idx].port.mapbase = _Ser3UTCR0;
                sa1100_ports[idx].port.irq     = IRQ_Ser3UART;
                sa1100_ports[idx].port.flags   = UPF_BOOT_AUTOCONF;
                break;

        default:
                printk(KERN_ERR "%s: bad port number %d\n", __func__, port);
        }
}


#ifdef CONFIG_SERIAL_SA1100_CONSOLE
static void sa1100_console_putchar(struct uart_port *port, int ch)
{
        struct sa1100_port *sport =
                container_of(port, struct sa1100_port, port);

        while (!(UART_GET_UTSR1(sport) & UTSR1_TNF))
                barrier();
        UART_PUT_CHAR(sport, ch);
}

/*
 * Interrupts are disabled on entering
 */
static void
sa1100_console_write(struct console *co, const char *s, unsigned int count)
{
        struct sa1100_port *sport = &sa1100_ports[co->index];
        unsigned int old_utcr3, status;

        /*
         *      First, save UTCR3 and then disable interrupts
         */
        old_utcr3 = UART_GET_UTCR3(sport);
        UART_PUT_UTCR3(sport, (old_utcr3 & ~(UTCR3_RIE | UTCR3_TIE)) |
                                UTCR3_TXE);

        uart_console_write(&sport->port, s, count, sa1100_console_putchar);

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore UTCR3
         */
        do {
                status = UART_GET_UTSR1(sport);
        } while (status & UTSR1_TBY);
        UART_PUT_UTCR3(sport, old_utcr3);
}

/*
 * If the port was already initialised (eg, by a boot loader),
 * try to determine the current setup.
 */
static void __init
sa1100_console_get_options(struct sa1100_port *sport, int *baud,
                           int *parity, int *bits)
{
        unsigned int utcr3;

        utcr3 = UART_GET_UTCR3(sport) & (UTCR3_RXE | UTCR3_TXE);
        if (utcr3 == (UTCR3_RXE | UTCR3_TXE)) {
                /* ok, the port was enabled */
                unsigned int utcr0, quot;

                utcr0 = UART_GET_UTCR0(sport);

                *parity = 'n';
                if (utcr0 & UTCR0_PE) {
                        if (utcr0 & UTCR0_OES)
                                *parity = 'e';
                        else
                                *parity = 'o';
                }

                if (utcr0 & UTCR0_DSS)
                        *bits = 8;
                else
                        *bits = 7;

                quot = UART_GET_UTCR2(sport) | UART_GET_UTCR1(sport) << 8;
                quot &= 0xfff;
                *baud = sport->port.uartclk / (16 * (quot + 1));
        }
}

static int __init
sa1100_console_setup(struct console *co, char *options)
{
        struct sa1100_port *sport;
        int baud = 9600;
        int bits = 8;
        int parity = 'n';
        int flow = 'n';

        /*
         * Check whether an invalid uart number has been specified, and
         * if so, search for the first available port that does have
         * console support.
         */
        if (co->index == -1 || co->index >= NR_PORTS)
                co->index = 0;
        sport = &sa1100_ports[co->index];

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);
        else
                sa1100_console_get_options(sport, &baud, &parity, &bits);

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

static struct uart_driver sa1100_reg;
static struct console sa1100_console = {
        .name           = "ttySA",
        .write          = sa1100_console_write,
        .device         = uart_console_device,
        .setup          = sa1100_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &sa1100_reg,
};

static int __init sa1100_rs_console_init(void)
{
        sa1100_init_ports();
        register_console(&sa1100_console);
        return 0;
}
console_initcall(sa1100_rs_console_init);

#define SA1100_CONSOLE  &sa1100_console
#else
#define SA1100_CONSOLE  NULL
#endif

static struct uart_driver sa1100_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "ttySA",
        .dev_name               = "ttySA",
        .major                  = SERIAL_SA1100_MAJOR,
        .minor                  = MINOR_START,
        .nr                     = NR_PORTS,
        .cons                   = SA1100_CONSOLE,
};

static int sa1100_serial_suspend(struct platform_device *dev, pm_message_t state)
{
        struct sa1100_port *sport = platform_get_drvdata(dev);

        if (sport)
                uart_suspend_port(&sa1100_reg, &sport->port);

        return 0;
}

static int sa1100_serial_resume(struct platform_device *dev)
{
        struct sa1100_port *sport = platform_get_drvdata(dev);

        if (sport)
                uart_resume_port(&sa1100_reg, &sport->port);

        return 0;
}

static int sa1100_serial_add_one_port(struct sa1100_port *sport, struct platform_device *dev)
{
        sport->port.dev = &dev->dev;
        sport->port.has_sysrq = IS_ENABLED(CONFIG_SERIAL_SA1100_CONSOLE);

        // mctrl_gpio_init() requires that the GPIO driver supports interrupts,
        // but we need to support GPIO drivers for hardware that has no such
        // interrupts.  Use mctrl_gpio_init_noauto() instead.
        sport->gpios = mctrl_gpio_init_noauto(sport->port.dev, 0);
        if (IS_ERR(sport->gpios)) {
                int err = PTR_ERR(sport->gpios);

                dev_err(sport->port.dev, "failed to get mctrl gpios: %d\n",
                        err);

                if (err == -EPROBE_DEFER)
                        return err;

                sport->gpios = NULL;
        }

        platform_set_drvdata(dev, sport);

        return uart_add_one_port(&sa1100_reg, &sport->port);
}

static int sa1100_serial_probe(struct platform_device *dev)
{
        struct resource *res;
        int i;

        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
        if (!res)
                return -EINVAL;

        for (i = 0; i < NR_PORTS; i++)
                if (sa1100_ports[i].port.mapbase == res->start)
                        break;
        if (i == NR_PORTS)
                return -ENODEV;

        sa1100_serial_add_one_port(&sa1100_ports[i], dev);

        return 0;
}

static int sa1100_serial_remove(struct platform_device *pdev)
{
        struct sa1100_port *sport = platform_get_drvdata(pdev);

        if (sport)
                uart_remove_one_port(&sa1100_reg, &sport->port);

        return 0;
}

static struct platform_driver sa11x0_serial_driver = {
        .probe          = sa1100_serial_probe,
        .remove         = sa1100_serial_remove,
        .suspend        = sa1100_serial_suspend,
        .resume         = sa1100_serial_resume,
        .driver         = {
                .name   = "sa11x0-uart",
        },
};

static int __init sa1100_serial_init(void)
{
        int ret;

        printk(KERN_INFO "Serial: SA11x0 driver\n");

        sa1100_init_ports();

        ret = uart_register_driver(&sa1100_reg);
        if (ret == 0) {
                ret = platform_driver_register(&sa11x0_serial_driver);
                if (ret)
                        uart_unregister_driver(&sa1100_reg);
        }
        return ret;
}

static void __exit sa1100_serial_exit(void)
{
        platform_driver_unregister(&sa11x0_serial_driver);
        uart_unregister_driver(&sa1100_reg);
}

module_init(sa1100_serial_init);
module_exit(sa1100_serial_exit);

MODULE_AUTHOR("Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("SA1100 generic serial port driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV_MAJOR(SERIAL_SA1100_MAJOR);
MODULE_ALIAS("platform:sa11x0-uart");