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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [drivers/] [char/] [serial_amba.c] - Blame information for rev 1765

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/*
 *  linux/drivers/char/serial_amba.c
 *
 *  Driver for AMBA 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
 *
 *
 * This is a generic driver for ARM AMBA-type serial ports.  They
 * have a lot of 16550-like features, but are not register compatable.
 * Note that although they do have CTS, DCD and DSR inputs, they do
 * not have an RI input, nor do they have DTR or RTS outputs.  If
 * required, these have to be supplied via some other means (eg, GPIO)
 * and hooked into this driver.
 *
 * This could very easily become a generic serial driver for dumb UARTs
 * (eg, {82,16x}50, 21285, SA1100).
 */
 
#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/string.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/console.h>
#include <linux/sysrq.h>
 
#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/bitops.h>
 
#include <asm/hardware/serial_amba.h>
 
#define SERIAL_AMBA_NAME        "ttyAM"
#define SERIAL_AMBA_MAJOR       204
#define SERIAL_AMBA_MINOR       16
#define SERIAL_AMBA_NR          2
 
#define CALLOUT_AMBA_NAME       "cuaam"
#define CALLOUT_AMBA_MAJOR      205
#define CALLOUT_AMBA_MINOR      16
#define CALLOUT_AMBA_NR         SERIAL_AMBA_NR
 
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
 
#define DEBUG 0
#define DEBUG_LEDS 0
 
#if DEBUG_LEDS
extern int get_leds(void);
extern int set_leds(int);
#endif
 
/*
 * Access routines for the AMBA UARTs
 */
#define UART_GET_INT_STATUS(p)  IO_READ((p)->uart_base + AMBA_UARTIIR)
#define UART_GET_FR(p)          IO_READ((p)->uart_base + AMBA_UARTFR)
#define UART_GET_CHAR(p)        IO_READ((p)->uart_base + AMBA_UARTDR)
#define UART_PUT_CHAR(p, c)     IO_WRITE((p)->uart_base + AMBA_UARTDR, (c))
#define UART_GET_RSR(p)         IO_READ((p)->uart_base + AMBA_UARTRSR)
#define UART_GET_CR(p)          IO_READ((p)->uart_base + AMBA_UARTCR)
#define UART_PUT_CR(p,c)        IO_WRITE((p)->uart_base + AMBA_UARTCR, (c))
#define UART_GET_LCRL(p)        IO_READ((p)->uart_base + AMBA_UARTLCR_L)
#define UART_PUT_LCRL(p,c)      IO_WRITE((p)->uart_base + AMBA_UARTLCR_L, (c))
#define UART_GET_LCRM(p)        IO_READ((p)->uart_base + AMBA_UARTLCR_M)
#define UART_PUT_LCRM(p,c)      IO_WRITE((p)->uart_base + AMBA_UARTLCR_M, (c))
#define UART_GET_LCRH(p)        IO_READ((p)->uart_base + AMBA_UARTLCR_H)
#define UART_PUT_LCRH(p,c)      IO_WRITE((p)->uart_base + AMBA_UARTLCR_H, (c))
#define UART_RX_DATA(s)         (((s) & AMBA_UARTFR_RXFE) == 0)
#define UART_TX_READY(s)        (((s) & AMBA_UARTFR_TXFF) == 0)
#define UART_TX_EMPTY(p)        ((UART_GET_FR(p) & AMBA_UARTFR_TMSK) == 0)
 
#define AMBA_UARTRSR_ANY        (AMBA_UARTRSR_OE|AMBA_UARTRSR_BE|AMBA_UARTRSR_PE|AMBA_UARTRSR_FE)
#define AMBA_UARTFR_MODEM_ANY   (AMBA_UARTFR_DCD|AMBA_UARTFR_DSR|AMBA_UARTFR_CTS)
 
/*
 * Things needed by tty driver
 */
static struct tty_driver ambanormal_driver, ambacallout_driver;
static int ambauart_refcount;
static struct tty_struct *ambauart_table[SERIAL_AMBA_NR];
static struct termios *ambauart_termios[SERIAL_AMBA_NR];
static struct termios *ambauart_termios_locked[SERIAL_AMBA_NR];
 
#if defined(CONFIG_SERIAL_AMBA_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
 
/*
 * Things needed internally to this driver
 */
 
/*
 * tmp_buf is used as a temporary buffer by serial_write.  We need to
 * lock it in case the copy_from_user blocks while swapping in a page,
 * and some other program tries to do a serial write at the same time.
 * Since the lock will only come under contention when the system is
 * swapping and available memory is low, it makes sense to share one
 * buffer across all the serial ports, since it significantly saves
 * memory if large numbers of serial ports are open.
 */
static u_char *tmp_buf;
static DECLARE_MUTEX(tmp_buf_sem);
 
#define HIGH_BITS_OFFSET        ((sizeof(long)-sizeof(int))*8)
 
/* number of characters left in xmit buffer before we ask for more */
#define WAKEUP_CHARS            256
#define AMBA_ISR_PASS_LIMIT     256
 
#define EVT_WRITE_WAKEUP        0
 
struct amba_icount {
        __u32   cts;
        __u32   dsr;
        __u32   rng;
        __u32   dcd;
        __u32   rx;
        __u32   tx;
        __u32   frame;
        __u32   overrun;
        __u32   parity;
        __u32   brk;
        __u32   buf_overrun;
};
 
/*
 * Static information about the port
 */
struct amba_port {
        unsigned int            uart_base;
        unsigned int            irq;
        unsigned int            uartclk;
        unsigned int            fifosize;
        unsigned int            tiocm_support;
        void (*set_mctrl)(struct amba_port *, u_int mctrl);
};
 
/*
 * This is the state information which is persistent across opens
 */
struct amba_state {
        struct amba_icount      icount;
        unsigned int            line;
        unsigned int            close_delay;
        unsigned int            closing_wait;
        unsigned int            custom_divisor;
        unsigned int            flags;
        struct termios          normal_termios;
        struct termios          callout_termios;
 
        int                     count;
        struct amba_info        *info;
};
 
#define AMBA_XMIT_SIZE 1024
/*
 * This is the state information which is only valid when the port is open.
 */
struct amba_info {
        struct amba_port        *port;
        struct amba_state       *state;
        struct tty_struct       *tty;
        unsigned char           x_char;
        unsigned char           old_status;
        unsigned char           read_status_mask;
        unsigned char           ignore_status_mask;
        struct circ_buf         xmit;
        unsigned int            flags;
#ifdef SUPPORT_SYSRQ
        unsigned long           sysrq;
#endif
 
        unsigned int            event;
        unsigned int            timeout;
        unsigned int            lcr_h;
        unsigned int            mctrl;
        int                     blocked_open;
        pid_t                   session;
        pid_t                   pgrp;
 
        struct tasklet_struct   tlet;
 
        wait_queue_head_t       open_wait;
        wait_queue_head_t       close_wait;
        wait_queue_head_t       delta_msr_wait;
};
 
#ifdef CONFIG_SERIAL_AMBA_CONSOLE
static struct console ambauart_cons;
#endif
static void ambauart_change_speed(struct amba_info *info, struct termios *old_termios);
static void ambauart_wait_until_sent(struct tty_struct *tty, int timeout);
 
#if 1 //def CONFIG_SERIAL_INTEGRATOR
static void amba_set_mctrl_null(struct amba_port *port, u_int mctrl)
{
}
 
static struct amba_port amba_ports[SERIAL_AMBA_NR] = {
        {
                uart_base:      IO_ADDRESS(INTEGRATOR_UART0_BASE),
                irq:            IRQ_UARTINT0,
                uartclk:        14745600,
                fifosize:       8,
                set_mctrl:      amba_set_mctrl_null,
        },
        {
                uart_base:      IO_ADDRESS(INTEGRATOR_UART1_BASE),
                irq:            IRQ_UARTINT1,
                uartclk:        14745600,
                fifosize:       8,
                set_mctrl:      amba_set_mctrl_null,
        }
};
#endif
 
static struct amba_state amba_state[SERIAL_AMBA_NR];
 
static void ambauart_enable_rx_interrupt(struct amba_info *info)
{
        unsigned int cr;
 
        cr = UART_GET_CR(info->port);
        cr |= AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE;
        UART_PUT_CR(info->port, cr);
}
 
static void ambauart_disable_rx_interrupt(struct amba_info *info)
{
        unsigned int cr;
 
        cr = UART_GET_CR(info->port);
        cr &= ~(AMBA_UARTCR_RIE | AMBA_UARTCR_RTIE);
        UART_PUT_CR(info->port, cr);
}
 
static void ambauart_enable_tx_interrupt(struct amba_info *info)
{
        unsigned int cr;
 
        cr = UART_GET_CR(info->port);
        cr |= AMBA_UARTCR_TIE;
        UART_PUT_CR(info->port, cr);
}
 
static void ambauart_disable_tx_interrupt(struct amba_info *info)
{
        unsigned int cr;
 
        cr = UART_GET_CR(info->port);
        cr &= ~AMBA_UARTCR_TIE;
        UART_PUT_CR(info->port, cr);
}
 
static void ambauart_stop(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
        save_flags(flags); cli();
        ambauart_disable_tx_interrupt(info);
        restore_flags(flags);
}
 
static void ambauart_start(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
        save_flags(flags); cli();
        if (info->xmit.head != info->xmit.tail
            && info->xmit.buf)
                ambauart_enable_tx_interrupt(info);
        restore_flags(flags);
}
 
 
/*
 * This routine is used by the interrupt handler to schedule
 * processing in the software interrupt portion of the driver.
 */
static void ambauart_event(struct amba_info *info, int event)
{
        info->event |= 1 << event;
        tasklet_schedule(&info->tlet);
}
 
static void
#ifdef SUPPORT_SYSRQ
ambauart_rx_chars(struct amba_info *info, struct pt_regs *regs)
#else
ambauart_rx_chars(struct amba_info *info)
#endif
{
        struct tty_struct *tty = info->tty;
        unsigned int status, ch, rsr, flg, ignored = 0;
        struct amba_icount *icount = &info->state->icount;
        struct amba_port *port = info->port;
 
        status = UART_GET_FR(port);
        while (UART_RX_DATA(status)) {
                ch = UART_GET_CHAR(port);
 
                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        goto ignore_char;
                icount->rx++;
 
                flg = TTY_NORMAL;
 
                /*
                 * Note that the error handling code is
                 * out of the main execution path
                 */
                rsr = UART_GET_RSR(port);
                if (rsr & AMBA_UARTRSR_ANY)
                        goto handle_error;
#ifdef SUPPORT_SYSRQ
                if (info->sysrq) {
                        if (ch && time_before(jiffies, info->sysrq)) {
                                handle_sysrq(ch, regs, NULL, NULL);
                                info->sysrq = 0;
                                goto ignore_char;
                        }
                        info->sysrq = 0;
                }
#endif
        error_return:
                *tty->flip.flag_buf_ptr++ = flg;
                *tty->flip.char_buf_ptr++ = ch;
                tty->flip.count++;
        ignore_char:
                status = UART_GET_FR(port);
        }
out:
        tty_flip_buffer_push(tty);
        return;
 
handle_error:
        if (rsr & AMBA_UARTRSR_BE) {
                rsr &= ~(AMBA_UARTRSR_FE | AMBA_UARTRSR_PE);
                icount->brk++;
 
#ifdef SUPPORT_SYSRQ
                if (info->state->line == ambauart_cons.index) {
                        if (!info->sysrq) {
                                info->sysrq = jiffies + HZ*5;
                                goto ignore_char;
                        }
                }
#endif
        } else if (rsr & AMBA_UARTRSR_PE)
                icount->parity++;
        else if (rsr & AMBA_UARTRSR_FE)
                icount->frame++;
        if (rsr & AMBA_UARTRSR_OE)
                icount->overrun++;
 
        if (rsr & info->ignore_status_mask) {
                if (++ignored > 100)
                        goto out;
                goto ignore_char;
        }
        rsr &= info->read_status_mask;
 
        if (rsr & AMBA_UARTRSR_BE)
                flg = TTY_BREAK;
        else if (rsr & AMBA_UARTRSR_PE)
                flg = TTY_PARITY;
        else if (rsr & AMBA_UARTRSR_FE)
                flg = TTY_FRAME;
 
        if (rsr & AMBA_UARTRSR_OE) {
                /*
                 * CHECK: does overrun affect the current character?
                 * ASSUMPTION: it does not.
                 */
                *tty->flip.flag_buf_ptr++ = flg;
                *tty->flip.char_buf_ptr++ = ch;
                tty->flip.count++;
                if (tty->flip.count >= TTY_FLIPBUF_SIZE)
                        goto ignore_char;
                ch = 0;
                flg = TTY_OVERRUN;
        }
#ifdef SUPPORT_SYSRQ
        info->sysrq = 0;
#endif
        goto error_return;
}
 
static void ambauart_tx_chars(struct amba_info *info)
{
        struct amba_port *port = info->port;
        int count;
 
        if (info->x_char) {
                UART_PUT_CHAR(port, info->x_char);
                info->state->icount.tx++;
                info->x_char = 0;
                return;
        }
        if (info->xmit.head == info->xmit.tail
            || info->tty->stopped
            || info->tty->hw_stopped) {
                ambauart_disable_tx_interrupt(info);
                return;
        }
 
        count = port->fifosize;
        do {
                UART_PUT_CHAR(port, info->xmit.buf[info->xmit.tail]);
                info->xmit.tail = (info->xmit.tail + 1) & (AMBA_XMIT_SIZE - 1);
                info->state->icount.tx++;
                if (info->xmit.head == info->xmit.tail)
                        break;
        } while (--count > 0);
 
        if (CIRC_CNT(info->xmit.head,
                     info->xmit.tail,
                     AMBA_XMIT_SIZE) < WAKEUP_CHARS)
                ambauart_event(info, EVT_WRITE_WAKEUP);
 
        if (info->xmit.head == info->xmit.tail) {
                ambauart_disable_tx_interrupt(info);
        }
}
 
static void ambauart_modem_status(struct amba_info *info)
{
        unsigned int status, delta;
        struct amba_icount *icount = &info->state->icount;
 
        status = UART_GET_FR(info->port) & AMBA_UARTFR_MODEM_ANY;
 
        delta = status ^ info->old_status;
        info->old_status = status;
 
        if (!delta)
                return;
 
        if (delta & AMBA_UARTFR_DCD) {
                icount->dcd++;
#ifdef CONFIG_HARD_PPS
                if ((info->flags & ASYNC_HARDPPS_CD) &&
                    (status & AMBA_UARTFR_DCD)
                        hardpps();
#endif
                if (info->flags & ASYNC_CHECK_CD) {
                        if (status & AMBA_UARTFR_DCD)
                                wake_up_interruptible(&info->open_wait);
                        else if (!((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                                   (info->flags & ASYNC_CALLOUT_NOHUP))) {
                                if (info->tty)
                                        tty_hangup(info->tty);
                        }
                }
        }
 
        if (delta & AMBA_UARTFR_DSR)
                icount->dsr++;
 
        if (delta & AMBA_UARTFR_CTS) {
                icount->cts++;
 
                if (info->flags & ASYNC_CTS_FLOW) {
                        status &= AMBA_UARTFR_CTS;
 
                        if (info->tty->hw_stopped) {
                                if (status) {
                                        info->tty->hw_stopped = 0;
                                        ambauart_enable_tx_interrupt(info);
                                        ambauart_event(info, EVT_WRITE_WAKEUP);
                                }
                        } else {
                                if (!status) {
                                        info->tty->hw_stopped = 1;
                                        ambauart_disable_tx_interrupt(info);
                                }
                        }
                }
        }
        wake_up_interruptible(&info->delta_msr_wait);
 
}
 
static void ambauart_int(int irq, void *dev_id, struct pt_regs *regs)
{
        struct amba_info *info = dev_id;
        unsigned int status, pass_counter = 0;
 
#if DEBUG_LEDS
        // tell the world
        set_leds(get_leds() | RED_LED);
#endif
 
        status = UART_GET_INT_STATUS(info->port);
        do {
                /*
                 * FIXME: what about clearing the interrupts?
                 */
 
                if (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS))
#ifdef SUPPORT_SYSRQ
                        ambauart_rx_chars(info, regs);
#else
                        ambauart_rx_chars(info);
#endif
                if (status & AMBA_UARTIIR_TIS)
                        ambauart_tx_chars(info);
                if (status & AMBA_UARTIIR_MIS)
                        ambauart_modem_status(info);
                if (pass_counter++ > AMBA_ISR_PASS_LIMIT)
                        break;
 
                status = UART_GET_INT_STATUS(info->port);
        } while (status & (AMBA_UARTIIR_RTIS | AMBA_UARTIIR_RIS | AMBA_UARTIIR_TIS));
 
#if DEBUG_LEDS
        // tell the world
        set_leds(get_leds() & ~RED_LED);
#endif
}
 
static void ambauart_tasklet_action(unsigned long data)
{
        struct amba_info *info = (struct amba_info *)data;
        struct tty_struct *tty;
 
        tty = info->tty;
        if (!tty || !test_and_clear_bit(EVT_WRITE_WAKEUP, &info->event))
                return;
 
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
            tty->ldisc.write_wakeup)
                (tty->ldisc.write_wakeup)(tty);
        wake_up_interruptible(&tty->write_wait);
}
 
static int ambauart_startup(struct amba_info *info)
{
        unsigned long flags;
        unsigned long page;
        int retval = 0;
 
        page = get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
 
        save_flags(flags); cli();
 
        if (info->flags & ASYNC_INITIALIZED) {
                free_page(page);
                goto errout;
        }
 
        if (info->xmit.buf)
                free_page(page);
        else
                info->xmit.buf = (unsigned char *) page;
 
        /*
         * Allocate the IRQ
         */
        retval = request_irq(info->port->irq, ambauart_int, 0, "amba", info);
        if (retval) {
                if (capable(CAP_SYS_ADMIN)) {
                        if (info->tty)
                                set_bit(TTY_IO_ERROR, &info->tty->flags);
                        retval = 0;
                }
                goto errout;
        }
 
        info->mctrl = 0;
        if (info->tty->termios->c_cflag & CBAUD)
                info->mctrl = TIOCM_RTS | TIOCM_DTR;
        info->port->set_mctrl(info->port, info->mctrl);
 
        /*
         * initialise the old status of the modem signals
         */
        info->old_status = UART_GET_FR(info->port) & AMBA_UARTFR_MODEM_ANY;
 
        /*
         * Finally, enable interrupts
         */
        ambauart_enable_rx_interrupt(info);
 
        if (info->tty)
                clear_bit(TTY_IO_ERROR, &info->tty->flags);
        info->xmit.head = info->xmit.tail = 0;
 
        /*
         * Set up the tty->alt_speed kludge
         */
        if (info->tty) {
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                        info->tty->alt_speed = 57600;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
                        info->tty->alt_speed = 115200;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
                        info->tty->alt_speed = 230400;
                if ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
                        info->tty->alt_speed = 460800;
        }
 
        /*
         * and set the speed of the serial port
         */
        ambauart_change_speed(info, 0);
 
        info->flags |= ASYNC_INITIALIZED;
        restore_flags(flags);
        return 0;
 
errout:
        restore_flags(flags);
        return retval;
}
 
/*
 * This routine will shutdown a serial port; interrupts are disabled, and
 * DTR is dropped if the hangup on close termio flag is on.
 */
static void ambauart_shutdown(struct amba_info *info)
{
        unsigned long flags;
 
        if (!(info->flags & ASYNC_INITIALIZED))
                return;
 
        save_flags(flags); cli(); /* Disable interrupts */
 
        /*
         * clear delta_msr_wait queue to avoid mem leaks: we may free the irq
         * here so the queue might never be woken up
         */
        wake_up_interruptible(&info->delta_msr_wait);
 
        /*
         * Free the IRQ
         */
        free_irq(info->port->irq, info);
 
        if (info->xmit.buf) {
                unsigned long pg = (unsigned long) info->xmit.buf;
                info->xmit.buf = NULL;
                free_page(pg);
        }
 
        /*
         * disable all interrupts, disable the port
         */
        UART_PUT_CR(info->port, 0);
 
        /* disable break condition and fifos */
        UART_PUT_LCRH(info->port, UART_GET_LCRH(info->port) &
                ~(AMBA_UARTLCR_H_BRK | AMBA_UARTLCR_H_FEN));
 
        if (!info->tty || (info->tty->termios->c_cflag & HUPCL))
                info->mctrl &= ~(TIOCM_DTR|TIOCM_RTS);
        info->port->set_mctrl(info->port, info->mctrl);
 
        /* kill off our tasklet */
        tasklet_kill(&info->tlet);
        if (info->tty)
                set_bit(TTY_IO_ERROR, &info->tty->flags);
 
        info->flags &= ~ASYNC_INITIALIZED;
        restore_flags(flags);
}
 
static void ambauart_change_speed(struct amba_info *info, struct termios *old_termios)
{
        unsigned int lcr_h, baud, quot, cflag, old_cr, bits;
        unsigned long flags;
 
        if (!info->tty || !info->tty->termios)
                return;
 
        cflag = info->tty->termios->c_cflag;
 
#if DEBUG
        printk("ambauart_set_cflag(0x%x) called\n", cflag);
#endif
        /* byte size and parity */
        switch (cflag & CSIZE) {
        case CS5: lcr_h = AMBA_UARTLCR_H_WLEN_5; bits = 7;  break;
        case CS6: lcr_h = AMBA_UARTLCR_H_WLEN_6; bits = 8;  break;
        case CS7: lcr_h = AMBA_UARTLCR_H_WLEN_7; bits = 9;  break;
        default:  lcr_h = AMBA_UARTLCR_H_WLEN_8; bits = 10; break; // CS8
        }
        if (cflag & CSTOPB) {
                lcr_h |= AMBA_UARTLCR_H_STP2;
                bits ++;
        }
        if (cflag & PARENB) {
                lcr_h |= AMBA_UARTLCR_H_PEN;
                bits++;
                if (!(cflag & PARODD))
                        lcr_h |= AMBA_UARTLCR_H_EPS;
        }
        if (info->port->fifosize > 1)
                lcr_h |= AMBA_UARTLCR_H_FEN;
 
        do {
                /* Determine divisor based on baud rate */
                baud = tty_get_baud_rate(info->tty);
                if (!baud)
                        baud = 9600;
 
                if (baud == 38400 &&
                    ((info->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST))
                        quot = info->state->custom_divisor;
                else
                        quot = (info->port->uartclk / (16 * baud)) - 1;
 
                if (!quot && old_termios) {
                        info->tty->termios->c_cflag &= ~CBAUD;
                        info->tty->termios->c_cflag |= (old_termios->c_cflag & CBAUD);
                        old_termios = NULL;
                }
        } while (quot == 0 && old_termios);
 
        /* As a last resort, if the quotient is zero, default to 9600 bps */
        if (!quot)
                quot = (info->port->uartclk / (16 * 9600)) - 1;
 
        info->timeout = (info->port->fifosize * HZ * bits * quot) /
                         (info->port->uartclk / 16);
        info->timeout += HZ/50;         /* Add .02 seconds of slop */
 
        if (cflag & CRTSCTS)
                info->flags |= ASYNC_CTS_FLOW;
        else
                info->flags &= ~ASYNC_CTS_FLOW;
        if (cflag & CLOCAL)
                info->flags &= ~ASYNC_CHECK_CD;
        else
                info->flags |= ASYNC_CHECK_CD;
 
        /*
         * Set up parity check flag
         */
#define RELEVENT_IFLAG(iflag)   ((iflag) & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
 
        info->read_status_mask = AMBA_UARTRSR_OE;
        if (I_INPCK(info->tty))
                info->read_status_mask |= AMBA_UARTRSR_FE | AMBA_UARTRSR_PE;
        if (I_BRKINT(info->tty) || I_PARMRK(info->tty))
                info->read_status_mask |= AMBA_UARTRSR_BE;
 
        /*
         * Characters to ignore
         */
        info->ignore_status_mask = 0;
        if (I_IGNPAR(info->tty))
                info->ignore_status_mask |= AMBA_UARTRSR_FE | AMBA_UARTRSR_PE;
        if (I_IGNBRK(info->tty)) {
                info->ignore_status_mask |= AMBA_UARTRSR_BE;
                /*
                 * If we're ignoring parity and break indicators,
                 * ignore overruns to (for real raw support).
                 */
                if (I_IGNPAR(info->tty))
                        info->ignore_status_mask |= AMBA_UARTRSR_OE;
        }
 
        /* first, disable everything */
        save_flags(flags); cli();
        old_cr = UART_GET_CR(info->port) &= ~AMBA_UARTCR_MSIE;
 
        if ((info->flags & ASYNC_HARDPPS_CD) ||
            (cflag & CRTSCTS) ||
            !(cflag & CLOCAL))
                old_cr |= AMBA_UARTCR_MSIE;
 
        UART_PUT_CR(info->port, 0);
        restore_flags(flags);
 
        /* Set baud rate */
        UART_PUT_LCRM(info->port, ((quot & 0xf00) >> 8));
        UART_PUT_LCRL(info->port, (quot & 0xff));
 
        /*
         * ----------v----------v----------v----------v-----
         * NOTE: MUST BE WRITTEN AFTER UARTLCR_M & UARTLCR_L
         * ----------^----------^----------^----------^-----
         */
        UART_PUT_LCRH(info->port, lcr_h);
        UART_PUT_CR(info->port, old_cr);
}
 
static void ambauart_put_char(struct tty_struct *tty, u_char ch)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
        if (!tty || !info->xmit.buf)
                return;
 
        save_flags(flags); cli();
        if (CIRC_SPACE(info->xmit.head, info->xmit.tail, AMBA_XMIT_SIZE) != 0) {
                info->xmit.buf[info->xmit.head] = ch;
                info->xmit.head = (info->xmit.head + 1) & (AMBA_XMIT_SIZE - 1);
        }
        restore_flags(flags);
}
 
static void ambauart_flush_chars(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
        if (info->xmit.head == info->xmit.tail
            || tty->stopped
            || tty->hw_stopped
            || !info->xmit.buf)
                return;
 
        save_flags(flags); cli();
        ambauart_enable_tx_interrupt(info);
        restore_flags(flags);
}
 
static int ambauart_write(struct tty_struct *tty, int from_user,
                          const u_char * buf, int count)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
        int c, ret = 0;
 
        if (!tty || !info->xmit.buf || !tmp_buf)
                return 0;
 
        save_flags(flags);
        if (from_user) {
                down(&tmp_buf_sem);
                while (1) {
                        int c1;
                        c = CIRC_SPACE_TO_END(info->xmit.head,
                                              info->xmit.tail,
                                              AMBA_XMIT_SIZE);
                        if (count < c)
                                c = count;
                        if (c <= 0)
                                break;
 
                        c -= copy_from_user(tmp_buf, buf, c);
                        if (!c) {
                                if (!ret)
                                        ret = -EFAULT;
                                break;
                        }
                        cli();
                        c1 = CIRC_SPACE_TO_END(info->xmit.head,
                                               info->xmit.tail,
                                               AMBA_XMIT_SIZE);
                        if (c1 < c)
                                c = c1;
                        memcpy(info->xmit.buf + info->xmit.head, tmp_buf, c);
                        info->xmit.head = (info->xmit.head + c) &
                                          (AMBA_XMIT_SIZE - 1);
                        restore_flags(flags);
                        buf += c;
                        count -= c;
                        ret += c;
                }
                up(&tmp_buf_sem);
        } else {
                cli();
                while (1) {
                        c = CIRC_SPACE_TO_END(info->xmit.head,
                                              info->xmit.tail,
                                              AMBA_XMIT_SIZE);
                        if (count < c)
                                c = count;
                        if (c <= 0)
                                break;
                        memcpy(info->xmit.buf + info->xmit.head, buf, c);
                        info->xmit.head = (info->xmit.head + c) &
                                          (AMBA_XMIT_SIZE - 1);
                        buf += c;
                        count -= c;
                        ret += c;
                }
                restore_flags(flags);
        }
        if (info->xmit.head != info->xmit.tail
            && !tty->stopped
            && !tty->hw_stopped)
                ambauart_enable_tx_interrupt(info);
        return ret;
}
 
static int ambauart_write_room(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
 
        return CIRC_SPACE(info->xmit.head, info->xmit.tail, AMBA_XMIT_SIZE);
}
 
static int ambauart_chars_in_buffer(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
 
        return CIRC_CNT(info->xmit.head, info->xmit.tail, AMBA_XMIT_SIZE);
}
 
static void ambauart_flush_buffer(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
#if DEBUG
        printk("ambauart_flush_buffer(%d) called\n",
               MINOR(tty->device) - tty->driver.minor_start);
#endif
        save_flags(flags); cli();
        info->xmit.head = info->xmit.tail = 0;
        restore_flags(flags);
        wake_up_interruptible(&tty->write_wait);
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) &&
            tty->ldisc.write_wakeup)
                (tty->ldisc.write_wakeup)(tty);
}
 
/*
 * This function is used to send a high-priority XON/XOFF character to
 * the device
 */
static void ambauart_send_xchar(struct tty_struct *tty, char ch)
{
        struct amba_info *info = tty->driver_data;
 
        info->x_char = ch;
        if (ch)
                ambauart_enable_tx_interrupt(info);
}
 
static void ambauart_throttle(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
 
        if (I_IXOFF(tty))
                ambauart_send_xchar(tty, STOP_CHAR(tty));
 
        if (tty->termios->c_cflag & CRTSCTS) {
                save_flags(flags); cli();
                info->mctrl &= ~TIOCM_RTS;
                info->port->set_mctrl(info->port, info->mctrl);
                restore_flags(flags);
        }
}
 
static void ambauart_unthrottle(struct tty_struct *tty)
{
        struct amba_info *info = (struct amba_info *) tty->driver_data;
        unsigned long flags;
 
        if (I_IXOFF(tty)) {
                if (info->x_char)
                        info->x_char = 0;
                else
                        ambauart_send_xchar(tty, START_CHAR(tty));
        }
 
        if (tty->termios->c_cflag & CRTSCTS) {
                save_flags(flags); cli();
                info->mctrl |= TIOCM_RTS;
                info->port->set_mctrl(info->port, info->mctrl);
                restore_flags(flags);
        }
}
 
static int get_serial_info(struct amba_info *info, struct serial_struct *retinfo)
{
        struct amba_state *state = info->state;
        struct amba_port *port = info->port;
        struct serial_struct tmp;
 
        memset(&tmp, 0, sizeof(tmp));
        tmp.type           = 0;
        tmp.line           = state->line;
        tmp.port           = port->uart_base;
        if (HIGH_BITS_OFFSET)
                tmp.port_high = port->uart_base >> HIGH_BITS_OFFSET;
        tmp.irq            = port->irq;
        tmp.flags          = 0;
        tmp.xmit_fifo_size = port->fifosize;
        tmp.baud_base      = port->uartclk / 16;
        tmp.close_delay    = state->close_delay;
        tmp.closing_wait   = state->closing_wait;
        tmp.custom_divisor = state->custom_divisor;
 
        if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
                return -EFAULT;
        return 0;
}
 
static int set_serial_info(struct amba_info *info,
                           struct serial_struct *newinfo)
{
        struct serial_struct new_serial;
        struct amba_state *state, old_state;
        struct amba_port *port;
        unsigned long new_port;
        unsigned int i, change_irq, change_port;
        int retval = 0;
 
        if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
                return -EFAULT;
 
        state = info->state;
        old_state = *state;
        port = info->port;
 
        new_port = new_serial.port;
        if (HIGH_BITS_OFFSET)
                new_port += (unsigned long) new_serial.port_high << HIGH_BITS_OFFSET;
 
        change_irq  = new_serial.irq != port->irq;
        change_port = new_port != port->uart_base;
 
        if (!capable(CAP_SYS_ADMIN)) {
                if (change_irq || change_port ||
                    (new_serial.baud_base != port->uartclk / 16) ||
                    (new_serial.close_delay != state->close_delay) ||
                    (new_serial.xmit_fifo_size != port->fifosize) ||
                    ((new_serial.flags & ~ASYNC_USR_MASK) !=
                     (state->flags & ~ASYNC_USR_MASK)))
                        return -EPERM;
                state->flags = ((state->flags & ~ASYNC_USR_MASK) |
                                (new_serial.flags & ASYNC_USR_MASK));
                info->flags = ((info->flags & ~ASYNC_USR_MASK) |
                               (new_serial.flags & ASYNC_USR_MASK));
                state->custom_divisor = new_serial.custom_divisor;
                goto check_and_exit;
        }
 
        if ((new_serial.irq >= NR_IRQS) || (new_serial.irq < 0) ||
            (new_serial.baud_base < 9600))
                return -EINVAL;
 
        if (new_serial.type && change_port) {
                for (i = 0; i < SERIAL_AMBA_NR; i++)
                        if ((port != amba_ports + i) &&
                            amba_ports[i].uart_base != new_port)
                                return -EADDRINUSE;
        }
 
        if ((change_port || change_irq) && (state->count > 1))
                return -EBUSY;
 
        /*
         * OK, past this point, all the error checking has been done.
         * At this point, we start making changes.....
         */
        port->uartclk = new_serial.baud_base * 16;
        state->flags = ((state->flags & ~ASYNC_FLAGS) |
                        (new_serial.flags & ASYNC_FLAGS));
        info->flags = ((state->flags & ~ASYNC_INTERNAL_FLAGS) |
                       (info->flags & ASYNC_INTERNAL_FLAGS));
        state->custom_divisor = new_serial.custom_divisor;
        state->close_delay = new_serial.close_delay * HZ / 100;
        state->closing_wait = new_serial.closing_wait * HZ / 100;
        info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
        port->fifosize = new_serial.xmit_fifo_size;
 
        if (change_port || change_irq) {
                /*
                 * We need to shutdown the serial port at the old
                 * port/irq combination.
                 */
                ambauart_shutdown(info);
                port->irq = new_serial.irq;
                port->uart_base = new_port;
        }
 
check_and_exit:
        if (!port->uart_base)
                return 0;
        if (info->flags & ASYNC_INITIALIZED) {
                if ((old_state.flags & ASYNC_SPD_MASK) !=
                    (state->flags & ASYNC_SPD_MASK) ||
                    (old_state.custom_divisor != state->custom_divisor)) {
                        if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                                info->tty->alt_speed = 57600;
                        if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
                                info->tty->alt_speed = 115200;
                        if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
                                info->tty->alt_speed = 230400;
                        if ((state->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
                                info->tty->alt_speed = 460800;
                        ambauart_change_speed(info, NULL);
                }
        } else
                retval = ambauart_startup(info);
        return retval;
}
 
 
/*
 * get_lsr_info - get line status register info
 */
static int get_lsr_info(struct amba_info *info, unsigned int *value)
{
        unsigned int result, status;
        unsigned long flags;
 
        save_flags(flags); cli();
        status = UART_GET_FR(info->port);
        restore_flags(flags);
        result = status & AMBA_UARTFR_BUSY ? TIOCSER_TEMT : 0;
 
        /*
         * If we're about to load something into the transmit
         * register, we'll pretend the transmitter isn't empty to
         * avoid a race condition (depending on when the transmit
         * interrupt happens).
         */
        if (info->x_char ||
            ((CIRC_CNT(info->xmit.head, info->xmit.tail,
                       AMBA_XMIT_SIZE) > 0) &&
             !info->tty->stopped && !info->tty->hw_stopped))
                result &= TIOCSER_TEMT;
 
        return put_user(result, value);
}
 
static int get_modem_info(struct amba_info *info, unsigned int *value)
{
        unsigned int result = info->mctrl;
        unsigned int status;
 
        status = UART_GET_FR(info->port);
        if (status & AMBA_UARTFR_DCD)
                result |= TIOCM_CAR;
        if (status & AMBA_UARTFR_DSR)
                result |= TIOCM_DSR;
        if (status & AMBA_UARTFR_CTS)
                result |= TIOCM_CTS;
 
        return put_user(result, value);
}
 
static int set_modem_info(struct amba_info *info, unsigned int cmd,
                          unsigned int *value)
{
        unsigned int arg, old;
        unsigned long flags;
 
        if (get_user(arg, value))
                return -EFAULT;
 
        old = info->mctrl;
        switch (cmd) {
        case TIOCMBIS:
                info->mctrl |= arg;
                break;
 
        case TIOCMBIC:
                info->mctrl &= ~arg;
                break;
 
        case TIOCMSET:
                info->mctrl = arg;
                break;
 
        default:
                return -EINVAL;
        }
        save_flags(flags); cli();
        if (old != info->mctrl)
                info->port->set_mctrl(info->port, info->mctrl);
        restore_flags(flags);
        return 0;
}
 
static void ambauart_break_ctl(struct tty_struct *tty, int break_state)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
        unsigned int lcr_h;
 
        save_flags(flags); cli();
        lcr_h = UART_GET_LCRH(info->port);
        if (break_state == -1)
                lcr_h |= AMBA_UARTLCR_H_BRK;
        else
                lcr_h &= ~AMBA_UARTLCR_H_BRK;
        UART_PUT_LCRH(info->port, lcr_h);
        restore_flags(flags);
}
 
static int ambauart_ioctl(struct tty_struct *tty, struct file *file,
                           unsigned int cmd, unsigned long arg)
{
        struct amba_info *info = tty->driver_data;
        struct amba_icount cprev, cnow;
        struct serial_icounter_struct icount;
        unsigned long flags;
 
        if ((cmd != TIOCGSERIAL) && (cmd != TIOCSSERIAL) &&
            (cmd != TIOCSERCONFIG) && (cmd != TIOCSERGSTRUCT) &&
            (cmd != TIOCMIWAIT) && (cmd != TIOCGICOUNT)) {
                if (tty->flags & (1 << TTY_IO_ERROR))
                        return -EIO;
        }
 
        switch (cmd) {
                case TIOCMGET:
                        return get_modem_info(info, (unsigned int *)arg);
                case TIOCMBIS:
                case TIOCMBIC:
                case TIOCMSET:
                        return set_modem_info(info, cmd, (unsigned int *)arg);
                case TIOCGSERIAL:
                        return get_serial_info(info,
                                               (struct serial_struct *)arg);
                case TIOCSSERIAL:
                        return set_serial_info(info,
                                               (struct serial_struct *)arg);
                case TIOCSERGETLSR: /* Get line status register */
                        return get_lsr_info(info, (unsigned int *)arg);
                /*
                 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
                 * - mask passed in arg for lines of interest
                 *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
                 * Caller should use TIOCGICOUNT to see which one it was
                 */
                case TIOCMIWAIT:
                        save_flags(flags); cli();
                        /* note the counters on entry */
                        cprev = info->state->icount;
                        /* Force modem status interrupts on */
                        UART_PUT_CR(info->port, UART_GET_CR(info->port) | AMBA_UARTCR_MSIE);
                        restore_flags(flags);
                        while (1) {
                                interruptible_sleep_on(&info->delta_msr_wait);
                                /* see if a signal did it */
                                if (signal_pending(current))
                                        return -ERESTARTSYS;
                                save_flags(flags); cli();
                                cnow = info->state->icount; /* atomic copy */
                                restore_flags(flags);
                                if (cnow.rng == cprev.rng && cnow.dsr == cprev.dsr &&
                                    cnow.dcd == cprev.dcd && cnow.cts == cprev.cts)
                                        return -EIO; /* no change => error */
                                if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
                                    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
                                    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
                                    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
                                        return 0;
                                }
                                cprev = cnow;
                        }
                        /* NOTREACHED */
 
                /*
                 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
                 * Return: write counters to the user passed counter struct
                 * NB: both 1->0 and 0->1 transitions are counted except for
                 *     RI where only 0->1 is counted.
                 */
                case TIOCGICOUNT:
                        save_flags(flags); cli();
                        cnow = info->state->icount;
                        restore_flags(flags);
                        icount.cts = cnow.cts;
                        icount.dsr = cnow.dsr;
                        icount.rng = cnow.rng;
                        icount.dcd = cnow.dcd;
                        icount.rx  = cnow.rx;
                        icount.tx  = cnow.tx;
                        icount.frame = cnow.frame;
                        icount.overrun = cnow.overrun;
                        icount.parity = cnow.parity;
                        icount.brk = cnow.brk;
                        icount.buf_overrun = cnow.buf_overrun;
 
                        return copy_to_user((void *)arg, &icount, sizeof(icount))
                                        ? -EFAULT : 0;
 
                default:
                        return -ENOIOCTLCMD;
        }
        return 0;
}
 
static void ambauart_set_termios(struct tty_struct *tty, struct termios *old_termios)
{
        struct amba_info *info = tty->driver_data;
        unsigned long flags;
        unsigned int cflag = tty->termios->c_cflag;
 
        if ((cflag ^ old_termios->c_cflag) == 0 &&
            RELEVENT_IFLAG(tty->termios->c_iflag ^ old_termios->c_iflag) == 0)
                return;
 
        ambauart_change_speed(info, old_termios);
 
        /* Handle transition to B0 status */
        if ((old_termios->c_cflag & CBAUD) &&
            !(cflag & CBAUD)) {
                save_flags(flags); cli();
                info->mctrl &= ~(TIOCM_RTS | TIOCM_DTR);
                info->port->set_mctrl(info->port, info->mctrl);
                restore_flags(flags);
        }
 
        /* Handle transition away from B0 status */
        if (!(old_termios->c_cflag & CBAUD) &&
            (cflag & CBAUD)) {
                save_flags(flags); cli();
                info->mctrl |= TIOCM_DTR;
                if (!(cflag & CRTSCTS) ||
                    !test_bit(TTY_THROTTLED, &tty->flags))
                        info->mctrl |= TIOCM_RTS;
                info->port->set_mctrl(info->port, info->mctrl);
                restore_flags(flags);
        }
 
        /* Handle turning off CRTSCTS */
        if ((old_termios->c_cflag & CRTSCTS) &&
            !(cflag & CRTSCTS)) {
                tty->hw_stopped = 0;
                ambauart_start(tty);
        }
 
#if 0
        /*
         * No need to wake up processes in open wait, since they
         * sample the CLOCAL flag once, and don't recheck it.
         * XXX  It's not clear whether the current behavior is correct
         * or not.  Hence, this may change.....
         */
        if (!(old_termios->c_cflag & CLOCAL) &&
            (tty->termios->c_cflag & CLOCAL))
                wake_up_interruptible(&info->open_wait);
#endif
}
 
static void ambauart_close(struct tty_struct *tty, struct file *filp)
{
        struct amba_info *info = tty->driver_data;
        struct amba_state *state;
        unsigned long flags;
 
        if (!info)
                return;
 
        state = info->state;
 
#if DEBUG
        printk("ambauart_close() called\n");
#endif
 
        save_flags(flags); cli();
 
        if (tty_hung_up_p(filp)) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }
 
        if ((tty->count == 1) && (state->count != 1)) {
                /*
                 * Uh, oh.  tty->count is 1, which means that the tty
                 * structure will be freed.  state->count should always
                 * be one in these conditions.  If it's greater than
                 * one, we've got real problems, since it means the
                 * serial port won't be shutdown.
                 */
                printk("ambauart_close: bad serial port count; tty->count is 1, "
                       "state->count is %d\n", state->count);
                state->count = 1;
        }
        if (--state->count < 0) {
                printk("rs_close: bad serial port count for %s%d: %d\n",
                       tty->driver.name, info->state->line, state->count);
                state->count = 0;
        }
        if (state->count) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);
                return;
        }
        info->flags |= ASYNC_CLOSING;
        restore_flags(flags);
        /*
         * Save the termios structure, since this port may have
         * separate termios for callout and dialin.
         */
        if (info->flags & ASYNC_NORMAL_ACTIVE)
                info->state->normal_termios = *tty->termios;
        if (info->flags & ASYNC_CALLOUT_ACTIVE)
                info->state->callout_termios = *tty->termios;
        /*
         * Now we wait for the transmit buffer to clear; and we notify
         * the line discipline to only process XON/XOFF characters.
         */
        tty->closing = 1;
        if (info->state->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, info->state->closing_wait);
        /*
         * At this point, we stop accepting input.  To do this, we
         * disable the receive line status interrupts.
         */
        if (info->flags & ASYNC_INITIALIZED) {
                ambauart_disable_rx_interrupt(info);
                /*
                 * Before we drop DTR, make sure the UART transmitter
                 * has completely drained; this is especially
                 * important if there is a transmit FIFO!
                 */
                ambauart_wait_until_sent(tty, info->timeout);
        }
        ambauart_shutdown(info);
        if (tty->driver.flush_buffer)
                tty->driver.flush_buffer(tty);
        if (tty->ldisc.flush_buffer)
                tty->ldisc.flush_buffer(tty);
        tty->closing = 0;
        info->event = 0;
        info->tty = NULL;
        if (info->blocked_open) {
                if (info->state->close_delay) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        schedule_timeout(info->state->close_delay);
                }
                wake_up_interruptible(&info->open_wait);
        }
        info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE|
                         ASYNC_CLOSING);
        wake_up_interruptible(&info->close_wait);
        MOD_DEC_USE_COUNT;
}
 
static void ambauart_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct amba_info *info = (struct amba_info *) tty->driver_data;
        unsigned long char_time, expire;
        unsigned int status;
 
        if (info->port->fifosize == 0)
                return;
 
        /*
         * Set the check interval to be 1/5 of the estimated time to
         * send a single character, and make it at least 1.  The check
         * interval should also be less than the timeout.
         *
         * Note: we have to use pretty tight timings here to satisfy
         * the NIST-PCTS.
         */
        char_time = (info->timeout - HZ/50) / info->port->fifosize;
        char_time = char_time / 5;
        if (char_time == 0)
                char_time = 1;
        if (timeout && timeout < char_time)
                char_time = timeout;
        /*
         * If the transmitter hasn't cleared in twice the approximate
         * amount of time to send the entire FIFO, it probably won't
         * ever clear.  This assumes the UART isn't doing flow
         * control, which is currently the case.  Hence, if it ever
         * takes longer than info->timeout, this is probably due to a
         * UART bug of some kind.  So, we clamp the timeout parameter at
         * 2*info->timeout.
         */
        if (!timeout || timeout > 2 * info->timeout)
                timeout = 2 * info->timeout;
 
        expire = jiffies + timeout;
#if DEBUG
        printk("ambauart_wait_until_sent(%d), jiff=%lu, expire=%lu...\n",
               MINOR(tty->device) - tty->driver.minor_start, jiffies,
               expire);
#endif
        while (UART_GET_FR(info->port) & AMBA_UARTFR_BUSY) {
                set_current_state(TASK_INTERRUPTIBLE);
                schedule_timeout(char_time);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, expire))
                        break;
                status = UART_GET_FR(info->port);
        }
        set_current_state(TASK_RUNNING);
}
 
static void ambauart_hangup(struct tty_struct *tty)
{
        struct amba_info *info = tty->driver_data;
        struct amba_state *state = info->state;
 
        ambauart_flush_buffer(tty);
        if (info->flags & ASYNC_CLOSING)
                return;
        ambauart_shutdown(info);
        info->event = 0;
        state->count = 0;
        info->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE);
        info->tty = NULL;
        wake_up_interruptible(&info->open_wait);
}
 
static int block_til_ready(struct tty_struct *tty, struct file *filp,
                           struct amba_info *info)
{
        DECLARE_WAITQUEUE(wait, current);
        struct amba_state *state = info->state;
        unsigned long flags;
        int do_clocal = 0, extra_count = 0, retval;
 
        /*
         * If the device is in the middle of being closed, then block
         * until it's done, and then try again.
         */
        if (tty_hung_up_p(filp) ||
            (info->flags & ASYNC_CLOSING)) {
                if (info->flags & ASYNC_CLOSING)
                        interruptible_sleep_on(&info->close_wait);
                return (info->flags & ASYNC_HUP_NOTIFY) ?
                        -EAGAIN : -ERESTARTSYS;
        }
 
        /*
         * If this is a callout device, then just make sure the normal
         * device isn't being used.
         */
        if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
                if (info->flags & ASYNC_NORMAL_ACTIVE)
                        return -EBUSY;
                if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (info->flags & ASYNC_SESSION_LOCKOUT) &&
                    (info->session != current->session))
                        return -EBUSY;
                if ((info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (info->flags & ASYNC_PGRP_LOCKOUT) &&
                    (info->pgrp != current->pgrp))
                        return -EBUSY;
                info->flags |= ASYNC_CALLOUT_ACTIVE;
                return 0;
        }
 
        /*
         * If non-blocking mode is set, or the port is not enabled,
         * then make the check up front and then exit.
         */
        if ((filp->f_flags & O_NONBLOCK) ||
            (tty->flags & (1 << TTY_IO_ERROR))) {
                if (info->flags & ASYNC_CALLOUT_ACTIVE)
                        return -EBUSY;
                info->flags |= ASYNC_NORMAL_ACTIVE;
                return 0;
        }
 
        if (info->flags & ASYNC_CALLOUT_ACTIVE) {
                if (state->normal_termios.c_cflag & CLOCAL)
                        do_clocal = 1;
        } else {
                if (tty->termios->c_cflag & CLOCAL)
                        do_clocal = 1;
        }
 
        /*
         * Block waiting for the carrier detect and the line to become
         * free (i.e., not in use by the callout).  While we are in
         * this loop, state->count is dropped by one, so that
         * rs_close() knows when to free things.  We restore it upon
         * exit, either normal or abnormal.
         */
        retval = 0;
        add_wait_queue(&info->open_wait, &wait);
        save_flags(flags); cli();
        if (!tty_hung_up_p(filp)) {
                extra_count = 1;
                state->count--;
        }
        restore_flags(flags);
        info->blocked_open++;
        while (1) {
                save_flags(flags); cli();
                if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (tty->termios->c_cflag & CBAUD)) {
                        info->mctrl = TIOCM_DTR | TIOCM_RTS;
                        info->port->set_mctrl(info->port, info->mctrl);
                }
                restore_flags(flags);
                set_current_state(TASK_INTERRUPTIBLE);
                if (tty_hung_up_p(filp) ||
                    !(info->flags & ASYNC_INITIALIZED)) {
                        if (info->flags & ASYNC_HUP_NOTIFY)
                                retval = -EAGAIN;
                        else
                                retval = -ERESTARTSYS;
                        break;
                }
                if (!(info->flags & ASYNC_CALLOUT_ACTIVE) &&
                    !(info->flags & ASYNC_CLOSING) &&
                    (do_clocal || (UART_GET_FR(info->port) & AMBA_UARTFR_DCD)))
                        break;
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
                schedule();
        }
        set_current_state(TASK_RUNNING);
        remove_wait_queue(&info->open_wait, &wait);
        if (extra_count)
                state->count++;
        info->blocked_open--;
        if (retval)
                return retval;
        info->flags |= ASYNC_NORMAL_ACTIVE;
        return 0;
}
 
static struct amba_info *ambauart_get(int line)
{
        struct amba_info *info;
        struct amba_state *state = amba_state + line;
 
        state->count++;
        if (state->info)
                return state->info;
        info = kmalloc(sizeof(struct amba_info), GFP_KERNEL);
        if (info) {
                memset(info, 0, sizeof(struct amba_info));
                init_waitqueue_head(&info->open_wait);
                init_waitqueue_head(&info->close_wait);
                init_waitqueue_head(&info->delta_msr_wait);
                info->flags = state->flags;
                info->state = state;
                info->port  = amba_ports + line;
                tasklet_init(&info->tlet, ambauart_tasklet_action,
                             (unsigned long)info);
        }
        if (state->info) {
                kfree(info);
                return state->info;
        }
        state->info = info;
        return info;
}
 
static int ambauart_open(struct tty_struct *tty, struct file *filp)
{
        struct amba_info *info;
        int retval, line = MINOR(tty->device) - tty->driver.minor_start;
 
#if DEBUG
        printk("ambauart_open(%d) called\n", line);
#endif
 
        // is this a line that we've got?
        MOD_INC_USE_COUNT;
        if (line >= SERIAL_AMBA_NR) {
                MOD_DEC_USE_COUNT;
                return -ENODEV;
        }
 
        info = ambauart_get(line);
        if (!info)
                return -ENOMEM;
 
        tty->driver_data = info;
        info->tty = tty;
        info->tty->low_latency = (info->flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 
        /*
         * Make sure we have the temporary buffer allocated
         */
        if (!tmp_buf) {
                unsigned long page = get_zeroed_page(GFP_KERNEL);
                if (tmp_buf)
                        free_page(page);
                else if (!page) {
                        MOD_DEC_USE_COUNT;
                        return -ENOMEM;
                }
                tmp_buf = (u_char *)page;
        }
 
        /*
         * If the port is in the middle of closing, bail out now.
         */
        if (tty_hung_up_p(filp) ||
            (info->flags & ASYNC_CLOSING)) {
                if (info->flags & ASYNC_CLOSING)
                        interruptible_sleep_on(&info->close_wait);
                MOD_DEC_USE_COUNT;
                return -EAGAIN;
        }
 
        /*
         * Start up the serial port
         */
        retval = ambauart_startup(info);
        if (retval) {
                MOD_DEC_USE_COUNT;
                return retval;
        }
 
        retval = block_til_ready(tty, filp, info);
        if (retval) {
                MOD_DEC_USE_COUNT;
                return retval;
        }
 
        if ((info->state->count == 1) &&
            (info->flags & ASYNC_SPLIT_TERMIOS)) {
                if (tty->driver.subtype == SERIAL_TYPE_NORMAL)
                        *tty->termios = info->state->normal_termios;
                else
                        *tty->termios = info->state->callout_termios;
        }
#ifdef CONFIG_SERIAL_AMBA_CONSOLE
        if (ambauart_cons.cflag && ambauart_cons.index == line) {
                tty->termios->c_cflag = ambauart_cons.cflag;
                ambauart_cons.cflag = 0;
        }
#endif
        ambauart_change_speed(info, NULL);
        info->session = current->session;
        info->pgrp = current->pgrp;
        return 0;
}
 
int __init ambauart_init(void)
{
        int i;
 
        ambanormal_driver.magic = TTY_DRIVER_MAGIC;
        ambanormal_driver.driver_name = "serial_amba";
        ambanormal_driver.name = SERIAL_AMBA_NAME;
        ambanormal_driver.major = SERIAL_AMBA_MAJOR;
        ambanormal_driver.minor_start = SERIAL_AMBA_MINOR;
        ambanormal_driver.num = SERIAL_AMBA_NR;
        ambanormal_driver.type = TTY_DRIVER_TYPE_SERIAL;
        ambanormal_driver.subtype = SERIAL_TYPE_NORMAL;
        ambanormal_driver.init_termios = tty_std_termios;
        ambanormal_driver.init_termios.c_cflag = B38400 | CS8 | CREAD | HUPCL | CLOCAL;
        ambanormal_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
        ambanormal_driver.refcount = &ambauart_refcount;
        ambanormal_driver.table = ambauart_table;
        ambanormal_driver.termios = ambauart_termios;
        ambanormal_driver.termios_locked = ambauart_termios_locked;
 
        ambanormal_driver.open = ambauart_open;
        ambanormal_driver.close = ambauart_close;
        ambanormal_driver.write = ambauart_write;
        ambanormal_driver.put_char = ambauart_put_char;
        ambanormal_driver.flush_chars = ambauart_flush_chars;
        ambanormal_driver.write_room = ambauart_write_room;
        ambanormal_driver.chars_in_buffer = ambauart_chars_in_buffer;
        ambanormal_driver.flush_buffer  = ambauart_flush_buffer;
        ambanormal_driver.ioctl = ambauart_ioctl;
        ambanormal_driver.throttle = ambauart_throttle;
        ambanormal_driver.unthrottle = ambauart_unthrottle;
        ambanormal_driver.send_xchar = ambauart_send_xchar;
        ambanormal_driver.set_termios = ambauart_set_termios;
        ambanormal_driver.stop = ambauart_stop;
        ambanormal_driver.start = ambauart_start;
        ambanormal_driver.hangup = ambauart_hangup;
        ambanormal_driver.break_ctl = ambauart_break_ctl;
        ambanormal_driver.wait_until_sent = ambauart_wait_until_sent;
        ambanormal_driver.read_proc = NULL;
 
        /*
         * The callout device is just like the normal device except for
         * the major number and the subtype code.
         */
        ambacallout_driver = ambanormal_driver;
        ambacallout_driver.name = CALLOUT_AMBA_NAME;
        ambacallout_driver.major = CALLOUT_AMBA_MAJOR;
        ambacallout_driver.subtype = SERIAL_TYPE_CALLOUT;
        ambacallout_driver.read_proc = NULL;
        ambacallout_driver.proc_entry = NULL;
 
        if (tty_register_driver(&ambanormal_driver))
                panic("Couldn't register AMBA serial driver\n");
        if (tty_register_driver(&ambacallout_driver))
                panic("Couldn't register AMBA callout driver\n");
 
        for (i = 0; i < SERIAL_AMBA_NR; i++) {
                struct amba_state *state = amba_state + i;
                state->line             = i;
                state->close_delay      = 5 * HZ / 10;
                state->closing_wait     = 30 * HZ;
                state->callout_termios  = ambacallout_driver.init_termios;
                state->normal_termios   = ambanormal_driver.init_termios;
        }
 
        return 0;
}
 
__initcall(ambauart_init);
 
#ifdef CONFIG_SERIAL_AMBA_CONSOLE
/************** console driver *****************/
 
/*
 * This code is currently never used; console->read is never called.
 * Therefore, although we have an implementation, we don't use it.
 * FIXME: the "const char *s" should be fixed to "char *s" some day.
 * (when the definition in include/linux/console.h is also fixed)
 */
#ifdef used_and_not_const_char_pointer
static int ambauart_console_read(struct console *co, const char *s, u_int count)
{
        struct amba_port *port = &amba_ports[co->index];
        unsigned int status;
        char *w;
        int c;
#if DEBUG
        printk("ambauart_console_read() called\n");
#endif
 
        c = 0;
        w = s;
        while (c < count) {
                status = UART_GET_FR(port);
                if (UART_RX_DATA(status)) {
                        *w++ = UART_GET_CHAR(port);
                        c++;
                } else {
                        // nothing more to get, return
                        return c;
                }
        }
        // return the count
        return c;
}
#endif
 
/*
 *      Print a string to the serial port trying not to disturb
 *      any possible real use of the port...
 *
 *      The console must be locked when we get here.
 */
static void ambauart_console_write(struct console *co, const char *s, u_int count)
{
        struct amba_port *port = &amba_ports[co->index];
        unsigned int status, old_cr;
        int i;
 
        /*
         *      First save the CR then disable the interrupts
         */
        old_cr = UART_GET_CR(port);
        UART_PUT_CR(port, AMBA_UARTCR_UARTEN);
 
        /*
         *      Now, do each character
         */
        for (i = 0; i < count; i++) {
                do {
                        status = UART_GET_FR(port);
                } while (!UART_TX_READY(status));
                UART_PUT_CHAR(port, s[i]);
                if (s[i] == '\n') {
                        do {
                                status = UART_GET_FR(port);
                        } while (!UART_TX_READY(status));
                        UART_PUT_CHAR(port, '\r');
                }
        }
 
        /*
         *      Finally, wait for transmitter to become empty
         *      and restore the TCR
         */
        do {
                status = UART_GET_FR(port);
        } while (status & AMBA_UARTFR_BUSY);
        UART_PUT_CR(port, old_cr);
}
 
static kdev_t ambauart_console_device(struct console *c)
{
        return MKDEV(SERIAL_AMBA_MAJOR, SERIAL_AMBA_MINOR + c->index);
}
 
static int __init ambauart_console_setup(struct console *co, char *options)
{
        struct amba_port *port;
        int baud = 38400;
        int bits = 8;
        int parity = 'n';
        u_int cflag = CREAD | HUPCL | CLOCAL;
        u_int lcr_h, quot;
 
        if (co->index >= SERIAL_AMBA_NR)
                co->index = 0;
 
        port = &amba_ports[co->index];
 
        if (options) {
                char *s = options;
                baud = simple_strtoul(s, NULL, 10);
                while (*s >= '0' && *s <= '9')
                        s++;
                if (*s) parity = *s++;
                if (*s) bits = *s - '0';
        }
 
        /*
         *    Now construct a cflag setting.
         */
        switch (baud) {
        case 1200:      cflag |= B1200;                 break;
        case 2400:      cflag |= B2400;                 break;
        case 4800:      cflag |= B4800;                 break;
        default:        cflag |= B9600;   baud = 9600;  break;
        case 19200:     cflag |= B19200;                break;
        case 38400:     cflag |= B38400;                break;
        case 57600:     cflag |= B57600;                break;
        case 115200:    cflag |= B115200;               break;
        }
        switch (bits) {
        case 7:   cflag |= CS7; lcr_h = AMBA_UARTLCR_H_WLEN_7;  break;
        default:  cflag |= CS8; lcr_h = AMBA_UARTLCR_H_WLEN_8;  break;
        }
        switch (parity) {
        case 'o':
        case 'O': cflag |= PARODD; lcr_h |= AMBA_UARTLCR_H_PEN; break;
        case 'e':
        case 'E': cflag |= PARENB; lcr_h |= AMBA_UARTLCR_H_PEN |
                                            AMBA_UARTLCR_H_EPS; break;
        }
 
        co->cflag = cflag;
 
        if (port->fifosize > 1)
                lcr_h |= AMBA_UARTLCR_H_FEN;
 
        quot = (port->uartclk / (16 * baud)) - 1;
 
        UART_PUT_LCRL(port, (quot & 0xff));
        UART_PUT_LCRM(port, (quot >> 8));
        UART_PUT_LCRH(port, lcr_h);
 
        /* we will enable the port as we need it */
        UART_PUT_CR(port, 0);
 
        return 0;
}
 
static struct console ambauart_cons =
{
        name:           SERIAL_AMBA_NAME,
        write:          ambauart_console_write,
#ifdef used_and_not_const_char_pointer
        read:           ambauart_console_read,
#endif
        device:         ambauart_console_device,
        setup:          ambauart_console_setup,
        flags:          CON_PRINTBUFFER,
        index:          -1,
};
 
void __init ambauart_console_init(void)
{
        register_console(&ambauart_cons);
}
 
#endif /* CONFIG_SERIAL_AMBA_CONSOLE */
 
MODULE_LICENSE("GPL");
EXPORT_NO_SYMBOLS;
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[/] [or1k/] [trunk/] [linux/] [linux-2.4/] [drivers/] [char/] [serial_amba.c] - Blame information for rev 1765

Line No.	Rev	Author	Line
1	1275	phoenix	`/*`
2			`* linux/drivers/char/serial_amba.c`
3			`*`
4			`* Driver for AMBA serial ports`
5			`*`
6			`* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.`
7			`*`
8			`* Copyright 1999 ARM Limited`
9			`* Copyright (C) 2000 Deep Blue Solutions Ltd.`
10			`*`
11			`* This program is free software; you can redistribute it and/or modify`
12			`* it under the terms of the GNU General Public License as published by`
13			`* the Free Software Foundation; either version 2 of the License, or`
14			`* (at your option) any later version.`
15			`*`
16			`* This program is distributed in the hope that it will be useful,`
17			`* but WITHOUT ANY WARRANTY; without even the implied warranty of`
18			`* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the`
19			`* GNU General Public License for more details.`
20			`*`
21			`* You should have received a copy of the GNU General Public License`
22			`* along with this program; if not, write to the Free Software`
23			`* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA`
24			`*`
25			`*`
26			`* This is a generic driver for ARM AMBA-type serial ports. They`
27			`* have a lot of 16550-like features, but are not register compatable.`
28			`* Note that although they do have CTS, DCD and DSR inputs, they do`
29			`* not have an RI input, nor do they have DTR or RTS outputs. If`
30			`* required, these have to be supplied via some other means (eg, GPIO)`
31			`* and hooked into this driver.`
32			`*`
33			`* This could very easily become a generic serial driver for dumb UARTs`
34			`* (eg, {82,16x}50, 21285, SA1100).`
35			`*/`
36
37			`#include <linux/config.h>`
38			`#include <linux/module.h>`
39			`#include <linux/errno.h>`
40			`#include <linux/signal.h>`