linux/drivers/serial/sunhv.c

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/* 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>
#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 pt_regs *regs)
{
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) {
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, regs);
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, regs))
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 = &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 pt_regs *regs)
{
struct uart_port *port = dev_id;
struct tty_struct *tty;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
tty = receive_chars(port, regs);
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;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
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++;
}
spin_unlock_irqrestore(&port->lock, flags);
}
/* 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 = 10000;
spin_lock_irqsave(&port->lock, flags);
while (limit-- > 0) {
long status = hypervisor_con_putchar(CON_BREAK);
if (status == HV_EOK)
break;
}
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 termios *termios,
struct termios *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",
.devfs_name = "tts/",
.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 = 10000;
spin_lock_irqsave(&port->lock, flags);
while (limit-- > 0) {
long status = hypervisor_con_putchar(c);
if (status == HV_EOK)
break;
}
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 int sunhv_console_setup(struct console *con, char *options)
{
return 0;
}
static struct console sunhv_console = {
.name = "ttyS",
.write = sunhv_console_write,
.device = uart_console_device,
.setup = sunhv_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &sunhv_reg,
};
static void __init sunhv_console_init(void)
{
if (con_is_present())
return;
sunhv_console.index = 0;
register_console(&sunhv_console);
}
static int __init sunhv_init(void)
{
struct uart_port *port;
int ret;
if (tlb_type != hypervisor)
return -ENODEV;
port = kmalloc(sizeof(struct uart_port), GFP_KERNEL);
if (unlikely(!port))
return -ENOMEM;
port->line = 0;
port->ops = &sunhv_pops;
port->type = PORT_SUNHV;
port->uartclk = ( 29491200 / 16 ); /* arbitrary */
/* XXX Get interrupt. XXX */
if (request_irq(0 /* XXX */, sunhv_interrupt,
SA_SHIRQ, "serial(sunhv)", port)) {
printk("sunhv: Cannot get IRQ %x\n",
0 /* XXX */);
kfree(port);
return -ENODEV;
}
sunhv_reg.minor = sunserial_current_minor;
sunhv_reg.nr = 1;
sunhv_reg.cons = &sunhv_console;
ret = uart_register_driver(&sunhv_reg);
if (ret < 0) {
free_irq(0 /* XXX */, up);
kfree(port);
return ret;
}
sunhv_port = port;
sunserial_current_minor += 1;
sunhv_console_init();
uart_add_one_port(&sunhv_reg, port);
return 0;
}
static void __exit sunhv_exit(void)
{
struct uart_port *port = sunhv_port;
BUG_ON(!port);
uart_remove_one_port(&sunhv_reg, port);
free_irq(0 /* XXX */, port);
sunserial_current_minor -= 1;
uart_unregister_driver(&sunhv_reg);
kfree(sunhv_port);
sunhv_port = NULL;
}
module_init(sunhv_init);
module_exit(sunhv_exit);
MODULE_AUTHOR("David S. Miller");
MODULE_DESCRIPTION("SUN4V Hypervisor console driver")
MODULE_LICENSE("GPL");