/*
 *  linux/drivers/char/clps711x.c
 *
 *  Driver for CLPS711x serial ports
 *
 *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
 *
 *  Copyright 1999 ARM Limited
 *  Copyright (C) 2000 Deep Blue Solutions Ltd.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#if defined(CONFIG_SERIAL_CLPS711X_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/spinlock.h>
#include <linux/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 <mach/hardware.h>
#include <asm/irq.h>
#include <asm/hardware/clps7111.h>

#define UART_NR         2

#define SERIAL_CLPS711X_MAJOR   204
#define SERIAL_CLPS711X_MINOR   40
#define SERIAL_CLPS711X_NR      UART_NR

/*
 * We use the relevant SYSCON register as a base address for these ports.
 */
#define UBRLCR(port)            ((port)->iobase + UBRLCR1 - SYSCON1)
#define UARTDR(port)            ((port)->iobase + UARTDR1 - SYSCON1)
#define SYSFLG(port)            ((port)->iobase + SYSFLG1 - SYSCON1)
#define SYSCON(port)            ((port)->iobase + SYSCON1 - SYSCON1)

#define TX_IRQ(port)            ((port)->irq)
#define RX_IRQ(port)            ((port)->irq + 1)

#define UART_ANY_ERR            (UARTDR_FRMERR | UARTDR_PARERR | UARTDR_OVERR)

#define tx_enabled(port)        ((port)->unused[0])

static void clps711xuart_stop_tx(struct uart_port *port)
{
        if (tx_enabled(port)) {
                disable_irq(TX_IRQ(port));
                tx_enabled(port) = 0;
        }
}

static void clps711xuart_start_tx(struct uart_port *port)
{
        if (!tx_enabled(port)) {
                enable_irq(TX_IRQ(port));
                tx_enabled(port) = 1;
        }
}

static void clps711xuart_stop_rx(struct uart_port *port)
{
        disable_irq(RX_IRQ(port));
}

static void clps711xuart_enable_ms(struct uart_port *port)
{
}

static irqreturn_t clps711xuart_int_rx(int irq, void *dev_id)
{
        struct uart_port *port = dev_id;
        struct tty_struct *tty = port->state->port.tty;
        unsigned int status, ch, flg;

        status = clps_readl(SYSFLG(port));
        while (!(status & SYSFLG_URXFE)) {
                ch = clps_readl(UARTDR(port));

                port->icount.rx++;

                flg = TTY_NORMAL;

                /*
                 * Note that the error handling code is
                 * out of the main execution path
                 */
                if (unlikely(ch & UART_ANY_ERR)) {
                        if (ch & UARTDR_PARERR)
                                port->icount.parity++;
                        else if (ch & UARTDR_FRMERR)
                                port->icount.frame++;
                        if (ch & UARTDR_OVERR)
                                port->icount.overrun++;

                        ch &= port->read_status_mask;

                        if (ch & UARTDR_PARERR)
                                flg = TTY_PARITY;
                        else if (ch & UARTDR_FRMERR)
                                flg = TTY_FRAME;

#ifdef SUPPORT_SYSRQ
                        port->sysrq = 0;
#endif
                }

                if (uart_handle_sysrq_char(port, ch))
                        goto ignore_char;

                /*
                 * CHECK: does overrun affect the current character?
                 * ASSUMPTION: it does not.
                 */
                uart_insert_char(port, ch, UARTDR_OVERR, ch, flg);

        ignore_char:
                status = clps_readl(SYSFLG(port));
        }
        tty_flip_buffer_push(tty);
        return IRQ_HANDLED;
}

static irqreturn_t clps711xuart_int_tx(int irq, void *dev_id)
{
        struct uart_port *port = dev_id;
        struct circ_buf *xmit = &port->state->xmit;
        int count;

        if (port->x_char) {
                clps_writel(port->x_char, UARTDR(port));
                port->icount.tx++;
                port->x_char = 0;
                return IRQ_HANDLED;
        }
        if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
                clps711xuart_stop_tx(port);
                return IRQ_HANDLED;
        }

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

        if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
                uart_write_wakeup(port);

        if (uart_circ_empty(xmit))
                clps711xuart_stop_tx(port);

        return IRQ_HANDLED;
}

static unsigned int clps711xuart_tx_empty(struct uart_port *port)
{
        unsigned int status = clps_readl(SYSFLG(port));
        return status & SYSFLG_UBUSY ? 0 : TIOCSER_TEMT;
}

static unsigned int clps711xuart_get_mctrl(struct uart_port *port)
{
        unsigned int port_addr;
        unsigned int result = 0;
        unsigned int status;

        port_addr = SYSFLG(port);
        if (port_addr == SYSFLG1) {
                status = clps_readl(SYSFLG1);
                if (status & SYSFLG1_DCD)
                        result |= TIOCM_CAR;
                if (status & SYSFLG1_DSR)
                        result |= TIOCM_DSR;
                if (status & SYSFLG1_CTS)
                        result |= TIOCM_CTS;
        }

        return result;
}

static void
clps711xuart_set_mctrl_null(struct uart_port *port, unsigned int mctrl)
{
}

static void clps711xuart_break_ctl(struct uart_port *port, int break_state)
{
        unsigned long flags;
        unsigned int ubrlcr;

        spin_lock_irqsave(&port->lock, flags);
        ubrlcr = clps_readl(UBRLCR(port));
        if (break_state == -1)
                ubrlcr |= UBRLCR_BREAK;
        else
                ubrlcr &= ~UBRLCR_BREAK;
        clps_writel(ubrlcr, UBRLCR(port));
        spin_unlock_irqrestore(&port->lock, flags);
}

static int clps711xuart_startup(struct uart_port *port)
{
        unsigned int syscon;
        int retval;

        tx_enabled(port) = 1;

        /*
         * Allocate the IRQs
         */
        retval = request_irq(TX_IRQ(port), clps711xuart_int_tx, 0,
                             "clps711xuart_tx", port);
        if (retval)
                return retval;

        retval = request_irq(RX_IRQ(port), clps711xuart_int_rx, 0,
                             "clps711xuart_rx", port);
        if (retval) {
                free_irq(TX_IRQ(port), port);
                return retval;
        }

        /*
         * enable the port
         */
        syscon = clps_readl(SYSCON(port));
        syscon |= SYSCON_UARTEN;
        clps_writel(syscon, SYSCON(port));

        return 0;
}

static void clps711xuart_shutdown(struct uart_port *port)
{
        unsigned int ubrlcr, syscon;

        /*
         * Free the interrupt
         */
        free_irq(TX_IRQ(port), port);   /* TX interrupt */
        free_irq(RX_IRQ(port), port);   /* RX interrupt */

        /*
         * disable the port
         */
        syscon = clps_readl(SYSCON(port));
        syscon &= ~SYSCON_UARTEN;
        clps_writel(syscon, SYSCON(port));

        /*
         * disable break condition and fifos
         */
        ubrlcr = clps_readl(UBRLCR(port));
        ubrlcr &= ~(UBRLCR_FIFOEN | UBRLCR_BREAK);
        clps_writel(ubrlcr, UBRLCR(port));
}

static void
clps711xuart_set_termios(struct uart_port *port, struct ktermios *termios,
                         struct ktermios *old)
{
        unsigned int ubrlcr, baud, quot;
        unsigned long flags;

        /*
         * We don't implement CREAD.
         */
        termios->c_cflag |= CREAD;

        /*
         * 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);

        switch (termios->c_cflag & CSIZE) {
        case CS5:
                ubrlcr = UBRLCR_WRDLEN5;
                break;
        case CS6:
                ubrlcr = UBRLCR_WRDLEN6;
                break;
        case CS7:
                ubrlcr = UBRLCR_WRDLEN7;
                break;
        default: // CS8
                ubrlcr = UBRLCR_WRDLEN8;
                break;
        }
        if (termios->c_cflag & CSTOPB)
                ubrlcr |= UBRLCR_XSTOP;
        if (termios->c_cflag & PARENB) {
                ubrlcr |= UBRLCR_PRTEN;
                if (!(termios->c_cflag & PARODD))
                        ubrlcr |= UBRLCR_EVENPRT;
        }
        if (port->fifosize > 1)
                ubrlcr |= UBRLCR_FIFOEN;

        spin_lock_irqsave(&port->lock, flags);

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

        port->read_status_mask = UARTDR_OVERR;
        if (termios->c_iflag & INPCK)
                port->read_status_mask |= UARTDR_PARERR | UARTDR_FRMERR;

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

        quot -= 1;

        clps_writel(ubrlcr | quot, UBRLCR(port));

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

static const char *clps711xuart_type(struct uart_port *port)
{
        return port->type == PORT_CLPS711X ? "CLPS711x" : NULL;
}

/*
 * Configure/autoconfigure the port.
 */
static void clps711xuart_config_port(struct uart_port *port, int flags)
{
        if (flags & UART_CONFIG_TYPE)
                port->type = PORT_CLPS711X;
}

static void clps711xuart_release_port(struct uart_port *port)
{
}

static int clps711xuart_request_port(struct uart_port *port)
{
        return 0;
}

static struct uart_ops clps711x_pops = {
        .tx_empty       = clps711xuart_tx_empty,
        .set_mctrl      = clps711xuart_set_mctrl_null,
        .get_mctrl      = clps711xuart_get_mctrl,
        .stop_tx        = clps711xuart_stop_tx,
        .start_tx       = clps711xuart_start_tx,
        .stop_rx        = clps711xuart_stop_rx,
        .enable_ms      = clps711xuart_enable_ms,
        .break_ctl      = clps711xuart_break_ctl,
        .startup        = clps711xuart_startup,
        .shutdown       = clps711xuart_shutdown,
        .set_termios    = clps711xuart_set_termios,
        .type           = clps711xuart_type,
        .config_port    = clps711xuart_config_port,
        .release_port   = clps711xuart_release_port,
        .request_port   = clps711xuart_request_port,
};

static struct uart_port clps711x_ports[UART_NR] = {
        {
                .iobase         = SYSCON1,
                .irq            = IRQ_UTXINT1, /* IRQ_URXINT1, IRQ_UMSINT */
                .uartclk        = 3686400,
                .fifosize       = 16,
                .ops            = &clps711x_pops,
                .line           = 0,
                .flags          = UPF_BOOT_AUTOCONF,
        },
        {
                .iobase         = SYSCON2,
                .irq            = IRQ_UTXINT2, /* IRQ_URXINT2 */
                .uartclk        = 3686400,
                .fifosize       = 16,
                .ops            = &clps711x_pops,
                .line           = 1,
                .flags          = UPF_BOOT_AUTOCONF,
        }
};

#ifdef CONFIG_SERIAL_CLPS711X_CONSOLE
static void clps711xuart_console_putchar(struct uart_port *port, int ch)
{
        while (clps_readl(SYSFLG(port)) & SYSFLG_UTXFF)
                barrier();
        clps_writel(ch, UARTDR(port));
}

/*
 *      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.
 *
 *      Note that this is called with interrupts already disabled
 */
static void
clps711xuart_console_write(struct console *co, const char *s,
                           unsigned int count)
{
        struct uart_port *port = clps711x_ports + co->index;
        unsigned int status, syscon;

        /*
         *      Ensure that the port is enabled.
         */
        syscon = clps_readl(SYSCON(port));
        clps_writel(syscon | SYSCON_UARTEN, SYSCON(port));

        uart_console_write(port, s, count, clps711xuart_console_putchar);

        /*
         *      Finally, wait for transmitter to become empty
         *      and restore the uart state.
         */
        do {
                status = clps_readl(SYSFLG(port));
        } while (status & SYSFLG_UBUSY);

        clps_writel(syscon, SYSCON(port));
}

static void __init
clps711xuart_console_get_options(struct uart_port *port, int *baud,
                                 int *parity, int *bits)
{
        if (clps_readl(SYSCON(port)) & SYSCON_UARTEN) {
                unsigned int ubrlcr, quot;

                ubrlcr = clps_readl(UBRLCR(port));

                *parity = 'n';
                if (ubrlcr & UBRLCR_PRTEN) {
                        if (ubrlcr & UBRLCR_EVENPRT)
                                *parity = 'e';
                        else
                                *parity = 'o';
                }

                if ((ubrlcr & UBRLCR_WRDLEN_MASK) == UBRLCR_WRDLEN7)
                        *bits = 7;
                else
                        *bits = 8;

                quot = ubrlcr & UBRLCR_BAUD_MASK;
                *baud = port->uartclk / (16 * (quot + 1));
        }
}

static int __init clps711xuart_console_setup(struct console *co, char *options)
{
        struct uart_port *port;
        int baud = 38400;
        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.
         */
        port = uart_get_console(clps711x_ports, UART_NR, co);

        if (options)
                uart_parse_options(options, &baud, &parity, &bits, &flow);
        else
                clps711xuart_console_get_options(port, &baud, &parity, &bits);

        return uart_set_options(port, co, baud, parity, bits, flow);
}

static struct uart_driver clps711x_reg;
static struct console clps711x_console = {
        .name           = "ttyCL",
        .write          = clps711xuart_console_write,
        .device         = uart_console_device,
        .setup          = clps711xuart_console_setup,
        .flags          = CON_PRINTBUFFER,
        .index          = -1,
        .data           = &clps711x_reg,
};

static int __init clps711xuart_console_init(void)
{
        register_console(&clps711x_console);
        return 0;
}
console_initcall(clps711xuart_console_init);

#define CLPS711X_CONSOLE        &clps711x_console
#else
#define CLPS711X_CONSOLE        NULL
#endif

static struct uart_driver clps711x_reg = {
        .driver_name            = "ttyCL",
        .dev_name               = "ttyCL",
        .major                  = SERIAL_CLPS711X_MAJOR,
        .minor                  = SERIAL_CLPS711X_MINOR,
        .nr                     = UART_NR,

        .cons                   = CLPS711X_CONSOLE,
};

static int __init clps711xuart_init(void)
{
        int ret, i;

        printk(KERN_INFO "Serial: CLPS711x driver\n");

        ret = uart_register_driver(&clps711x_reg);
        if (ret)
                return ret;

        for (i = 0; i < UART_NR; i++)
                uart_add_one_port(&clps711x_reg, &clps711x_ports[i]);

        return 0;
}

static void __exit clps711xuart_exit(void)
{
        int i;

        for (i = 0; i < UART_NR; i++)
                uart_remove_one_port(&clps711x_reg, &clps711x_ports[i]);

        uart_unregister_driver(&clps711x_reg);
}

module_init(clps711xuart_init);
module_exit(clps711xuart_exit);

MODULE_AUTHOR("Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("CLPS-711x generic serial driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS_CHARDEV(SERIAL_CLPS711X_MAJOR, SERIAL_CLPS711X_MINOR);