Linux 2.6.20.7

[linux/fpc-iii.git] / drivers / serial / sunhv.c

/* sunhv.c: Serial driver for SUN4V hypervisor console.
 *
 * Copyright (C) 2006 David S. Miller (davem@davemloft.net)
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/major.h>
#include <linux/circ_buf.h>
#include <linux/serial.h>
#include <linux/sysrq.h>
#include <linux/console.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/init.h>

#include <asm/hypervisor.h>
#include <asm/spitfire.h>
#include <asm/prom.h>
#include <asm/of_device.h>
#include <asm/irq.h>

#if defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif

#include <linux/serial_core.h>

#include "suncore.h"

#define CON_BREAK       ((long)-1)
#define CON_HUP         ((long)-2)

static inline long hypervisor_con_getchar(long *status)
{
        register unsigned long func asm("%o5");
        register unsigned long arg0 asm("%o0");
        register unsigned long arg1 asm("%o1");

        func = HV_FAST_CONS_GETCHAR;
        arg0 = 0;
        arg1 = 0;
        __asm__ __volatile__("ta        %6"
                             : "=&r" (func), "=&r" (arg0), "=&r" (arg1)
                             : "0" (func), "1" (arg0), "2" (arg1),
                               "i" (HV_FAST_TRAP));

        *status = arg0;

        return (long) arg1;
}

static inline long hypervisor_con_putchar(long ch)
{
        register unsigned long func asm("%o5");
        register unsigned long arg0 asm("%o0");

        func = HV_FAST_CONS_PUTCHAR;
        arg0 = ch;
        __asm__ __volatile__("ta        %4"
                             : "=&r" (func), "=&r" (arg0)
                             : "0" (func), "1" (arg0), "i" (HV_FAST_TRAP));

        return (long) arg0;
}

#define IGNORE_BREAK    0x1
#define IGNORE_ALL      0x2

static int hung_up = 0;

static struct tty_struct *receive_chars(struct uart_port *port)
{
        struct tty_struct *tty = NULL;
        int saw_console_brk = 0;
        int limit = 10000;

        if (port->info != NULL)         /* Unopened serial console */
                tty = port->info->tty;

        while (limit-- > 0) {
                long status;
                long c = hypervisor_con_getchar(&status);
                unsigned char flag;

                if (status == HV_EWOULDBLOCK)
                        break;

                if (c == CON_BREAK) {
                        if (uart_handle_break(port))
                                continue;
                        saw_console_brk = 1;
                        c = 0;
                }

                if (c == CON_HUP) {
                        hung_up = 1;
                        uart_handle_dcd_change(port, 0);
                } else if (hung_up) {
                        hung_up = 0;
                        uart_handle_dcd_change(port, 1);
                }

                if (tty == NULL) {
                        uart_handle_sysrq_char(port, c);
                        continue;
                }

                flag = TTY_NORMAL;
                port->icount.rx++;
                if (c == CON_BREAK) {
                        port->icount.brk++;
                        if (uart_handle_break(port))
                                continue;
                        flag = TTY_BREAK;
                }

                if (uart_handle_sysrq_char(port, c))
                        continue;

                if ((port->ignore_status_mask & IGNORE_ALL) ||
                    ((port->ignore_status_mask & IGNORE_BREAK) &&
                     (c == CON_BREAK)))
                        continue;

                tty_insert_flip_char(tty, c, flag);
        }

        if (saw_console_brk)
                sun_do_break();

        return tty;
}

static void transmit_chars(struct uart_port *port)
{
        struct circ_buf *xmit;

        if (!port->info)
                return;

        xmit = &port->info->xmit;
        if (uart_circ_empty(xmit) || uart_tx_stopped(port))
                return;

        while (!uart_circ_empty(xmit)) {
                long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);

                if (status != HV_EOK)
                        break;

                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                port->icount.tx++;
        }

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

static irqreturn_t sunhv_interrupt(int irq, void *dev_id)
{
        struct uart_port *port = dev_id;
        struct tty_struct *tty;
        unsigned long flags;

        spin_lock_irqsave(&port->lock, flags);
        tty = receive_chars(port);
        transmit_chars(port);
        spin_unlock_irqrestore(&port->lock, flags);

        if (tty)
                tty_flip_buffer_push(tty);

        return IRQ_HANDLED;
}

/* port->lock is not held.  */
static unsigned int sunhv_tx_empty(struct uart_port *port)
{
        /* Transmitter is always empty for us.  If the circ buffer
         * is non-empty or there is an x_char pending, our caller
         * will do the right thing and ignore what we return here.
         */
        return TIOCSER_TEMT;
}

/* port->lock held by caller.  */
static void sunhv_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
        return;
}

/* port->lock is held by caller and interrupts are disabled.  */
static unsigned int sunhv_get_mctrl(struct uart_port *port)
{
        return TIOCM_DSR | TIOCM_CAR | TIOCM_CTS;
}

/* port->lock held by caller.  */
static void sunhv_stop_tx(struct uart_port *port)
{
        return;
}

/* port->lock held by caller.  */
static void sunhv_start_tx(struct uart_port *port)
{
        struct circ_buf *xmit = &port->info->xmit;

        while (!uart_circ_empty(xmit)) {
                long status = hypervisor_con_putchar(xmit->buf[xmit->tail]);

                if (status != HV_EOK)
                        break;

                xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
                port->icount.tx++;
        }
}

/* port->lock is not held.  */
static void sunhv_send_xchar(struct uart_port *port, char ch)
{
        unsigned long flags;
        int limit = 10000;

        spin_lock_irqsave(&port->lock, flags);

        while (limit-- > 0) {
                long status = hypervisor_con_putchar(ch);
                if (status == HV_EOK)
                        break;
        }

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

/* port->lock held by caller.  */
static void sunhv_stop_rx(struct uart_port *port)
{
}

/* port->lock held by caller.  */
static void sunhv_enable_ms(struct uart_port *port)
{
}

/* port->lock is not held.  */
static void sunhv_break_ctl(struct uart_port *port, int break_state)
{
        if (break_state) {
                unsigned long flags;
                int limit = 1000000;

                spin_lock_irqsave(&port->lock, flags);

                while (limit-- > 0) {
                        long status = hypervisor_con_putchar(CON_BREAK);
                        if (status == HV_EOK)
                                break;
                        udelay(2);
                }

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

/* port->lock is not held.  */
static int sunhv_startup(struct uart_port *port)
{
        return 0;
}

/* port->lock is not held.  */
static void sunhv_shutdown(struct uart_port *port)
{
}

/* port->lock is not held.  */
static void sunhv_set_termios(struct uart_port *port, struct ktermios *termios,
                              struct ktermios *old)
{
        unsigned int baud = uart_get_baud_rate(port, termios, old, 0, 4000000);
        unsigned int quot = uart_get_divisor(port, baud);
        unsigned int iflag, cflag;
        unsigned long flags;

        spin_lock_irqsave(&port->lock, flags);

        iflag = termios->c_iflag;
        cflag = termios->c_cflag;

        port->ignore_status_mask = 0;
        if (iflag & IGNBRK)
                port->ignore_status_mask |= IGNORE_BREAK;
        if ((cflag & CREAD) == 0)
                port->ignore_status_mask |= IGNORE_ALL;

        /* XXX */
        uart_update_timeout(port, cflag,
                            (port->uartclk / (16 * quot)));

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

static const char *sunhv_type(struct uart_port *port)
{
        return "SUN4V HCONS";
}

static void sunhv_release_port(struct uart_port *port)
{
}

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

static void sunhv_config_port(struct uart_port *port, int flags)
{
}

static int sunhv_verify_port(struct uart_port *port, struct serial_struct *ser)
{
        return -EINVAL;
}

static struct uart_ops sunhv_pops = {
        .tx_empty       = sunhv_tx_empty,
        .set_mctrl      = sunhv_set_mctrl,
        .get_mctrl      = sunhv_get_mctrl,
        .stop_tx        = sunhv_stop_tx,
        .start_tx       = sunhv_start_tx,
        .send_xchar     = sunhv_send_xchar,
        .stop_rx        = sunhv_stop_rx,
        .enable_ms      = sunhv_enable_ms,
        .break_ctl      = sunhv_break_ctl,
        .startup        = sunhv_startup,
        .shutdown       = sunhv_shutdown,
        .set_termios    = sunhv_set_termios,
        .type           = sunhv_type,
        .release_port   = sunhv_release_port,
        .request_port   = sunhv_request_port,
        .config_port    = sunhv_config_port,
        .verify_port    = sunhv_verify_port,
};

static struct uart_driver sunhv_reg = {
        .owner                  = THIS_MODULE,
        .driver_name            = "serial",
        .dev_name               = "ttyS",
        .major                  = TTY_MAJOR,
};

static struct uart_port *sunhv_port;

static inline void sunhv_console_putchar(struct uart_port *port, char c)
{
        unsigned long flags;
        int limit = 1000000;

        spin_lock_irqsave(&port->lock, flags);

        while (limit-- > 0) {
                long status = hypervisor_con_putchar(c);
                if (status == HV_EOK)
                        break;
                udelay(2);
        }

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

static void sunhv_console_write(struct console *con, const char *s, unsigned n)
{
        struct uart_port *port = sunhv_port;
        int i;

        for (i = 0; i < n; i++) {
                if (*s == '\n')
                        sunhv_console_putchar(port, '\r');
                sunhv_console_putchar(port, *s++);
        }
}

static struct console sunhv_console = {
        .name   =       "ttyHV",
        .write  =       sunhv_console_write,
        .device =       uart_console_device,
        .flags  =       CON_PRINTBUFFER,
        .index  =       -1,
        .data   =       &sunhv_reg,
};

static inline struct console *SUNHV_CONSOLE(void)
{
        if (con_is_present())
                return NULL;

        sunhv_console.index = 0;

        return &sunhv_console;
}

static int __devinit hv_probe(struct of_device *op, const struct of_device_id *match)
{
        struct uart_port *port;
        int err;

        if (op->irqs[0] == 0xffffffff)
                return -ENODEV;

        port = kzalloc(sizeof(struct uart_port), GFP_KERNEL);
        if (unlikely(!port))
                return -ENOMEM;

        sunhv_port = port;

        port->line = 0;
        port->ops = &sunhv_pops;
        port->type = PORT_SUNHV;
        port->uartclk = ( 29491200 / 16 ); /* arbitrary */

        port->membase = (unsigned char __iomem *) __pa(port);

        port->irq = op->irqs[0];

        port->dev = &op->dev;

        sunhv_reg.minor = sunserial_current_minor;
        sunhv_reg.nr = 1;

        err = uart_register_driver(&sunhv_reg);
        if (err)
                goto out_free_port;

        sunhv_reg.tty_driver->name_base = sunhv_reg.minor - 64;
        sunserial_current_minor += 1;

        sunhv_reg.cons = SUNHV_CONSOLE();

        err = uart_add_one_port(&sunhv_reg, port);
        if (err)
                goto out_unregister_driver;

        err = request_irq(port->irq, sunhv_interrupt, 0, "hvcons", port);
        if (err)
                goto out_remove_port;

        dev_set_drvdata(&op->dev, port);

        return 0;

out_remove_port:
        uart_remove_one_port(&sunhv_reg, port);

out_unregister_driver:
        sunserial_current_minor -= 1;
        uart_unregister_driver(&sunhv_reg);

out_free_port:
        kfree(port);
        sunhv_port = NULL;
        return err;
}

static int __devexit hv_remove(struct of_device *dev)
{
        struct uart_port *port = dev_get_drvdata(&dev->dev);

        free_irq(port->irq, port);

        uart_remove_one_port(&sunhv_reg, port);

        sunserial_current_minor -= 1;
        uart_unregister_driver(&sunhv_reg);

        kfree(port);
        sunhv_port = NULL;

        dev_set_drvdata(&dev->dev, NULL);

        return 0;
}

static struct of_device_id hv_match[] = {
        {
                .name = "console",
                .compatible = "qcn",
        },
        {},
};
MODULE_DEVICE_TABLE(of, hv_match);

static struct of_platform_driver hv_driver = {
        .name           = "hv",
        .match_table    = hv_match,
        .probe          = hv_probe,
        .remove         = __devexit_p(hv_remove),
};

static int __init sunhv_init(void)
{
        if (tlb_type != hypervisor)
                return -ENODEV;

        return of_register_driver(&hv_driver, &of_bus_type);
}

static void __exit sunhv_exit(void)
{
        of_unregister_driver(&hv_driver);
}

module_init(sunhv_init);
module_exit(sunhv_exit);

MODULE_AUTHOR("David S. Miller");
MODULE_DESCRIPTION("SUN4V Hypervisor console driver");
MODULE_VERSION("2.0");
MODULE_LICENSE("GPL");