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/******************************************************************************
* console.c
*/
#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/serial.h>
#include <linux/major.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/console.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <asm/hypervisor.h>
#define XENO_TTY_MINOR 123
/*** Useful function for console debugging -- goes straight to Xen ****/
asmlinkage int xprintk(const char *fmt, ...)
{
va_list args;
int printk_len;
static char printk_buf[1024];
/* Emit the output into the temporary buffer */
va_start(args, fmt);
printk_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
va_end(args);
/* Send the processed output directly to Xen. */
(void)HYPERVISOR_console_write(printk_buf, printk_len);
return 0;
}
/******************** Kernel console driver ********************************/
static void xen_console_write(struct console *co, const char *s, unsigned count)
{
#define STRLEN 256
static char str[STRLEN];
static int pos = 0;
int len;
/* We buffer output until we see a newline, or until the buffer is full. */
while ( count != 0 )
{
len = ((STRLEN - pos) > count) ? count : STRLEN - pos;
memcpy(str + pos, s, len);
pos += len;
s += len;
count -= len;
if ( (pos == STRLEN) || (str[pos-1] == '\n') )
{
(void)HYPERVISOR_console_write(str, pos);
pos = 0;
}
}
}
static kdev_t xen_console_device(struct console *c)
{
/*
* This is the magic that binds our "struct console" to our
* "tty_struct", defined below.
*/
return MKDEV(TTY_MAJOR, XENO_TTY_MINOR);
}
static struct console xen_console_info = {
name: "xencons", /* Used to be xen_console, but we're only
actually allowed 8 charcters including
the terminator... */
write: xen_console_write,
device: xen_console_device,
flags: CON_PRINTBUFFER,
index: -1,
};
void xen_console_init(void)
{
xprintk("xen_console_init\n");
register_console(&xen_console_info);
}
/******************** Initial /dev/console *********************************/
static struct tty_driver xeno_console_driver;
static int xeno_console_refcount;
static struct tty_struct *xeno_console_table[1];
static struct termios *xeno_console_termios[1];
static struct termios *xeno_console_termios_locked[1];
static int xeno_console_write_room(struct tty_struct *tty)
{
return INT_MAX;
}
static int xeno_console_chars_in_buffer(struct tty_struct *tty)
{
return 0;
}
static inline int xeno_console_xmit(int ch)
{
char _ch = ch;
xen_console_write(NULL, &_ch, 1);
return 1;
}
static int xeno_console_write(struct tty_struct *tty, int from_user,
const u_char * buf, int count)
{
int i;
if ( from_user && verify_area(VERIFY_READ, buf, count) )
{
return -EINVAL;
}
for ( i = 0; i < count; i++ )
{
char ch;
if ( from_user )
{
__get_user(ch, buf + i);
}
else
{
ch = buf[i];
}
xeno_console_xmit(ch);
}
return i;
}
static void xeno_console_put_char(struct tty_struct *tty, u_char ch)
{
xeno_console_xmit(ch);
}
static int xeno_console_open(struct tty_struct *tty, struct file *filp)
{
int line;
MOD_INC_USE_COUNT;
line = MINOR(tty->device) - tty->driver.minor_start;
if ( line )
{
MOD_DEC_USE_COUNT;
return -ENODEV;
}
tty->driver_data = NULL;
return 0;
}
static void xeno_console_close(struct tty_struct *tty, struct file *filp)
{
MOD_DEC_USE_COUNT;
}
int __init xeno_con_init(void)
{
memset(&xeno_console_driver, 0, sizeof(struct tty_driver));
xeno_console_driver.magic = TTY_DRIVER_MAGIC;
xeno_console_driver.driver_name = "xeno_console";
xeno_console_driver.name = "xencon";
xeno_console_driver.major = TTY_MAJOR;
xeno_console_driver.minor_start = XENO_TTY_MINOR;
xeno_console_driver.num = 1;
xeno_console_driver.type = TTY_DRIVER_TYPE_SERIAL;
xeno_console_driver.subtype = SERIAL_TYPE_NORMAL;
xeno_console_driver.init_termios = tty_std_termios;
xeno_console_driver.flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_NO_DEVFS;
xeno_console_driver.refcount = &xeno_console_refcount;
xeno_console_driver.table = xeno_console_table;
xeno_console_driver.termios = xeno_console_termios;
xeno_console_driver.termios_locked = xeno_console_termios_locked;
/* Functions */
xeno_console_driver.open = xeno_console_open;
xeno_console_driver.close = xeno_console_close;
xeno_console_driver.write = xeno_console_write;
xeno_console_driver.write_room = xeno_console_write_room;
xeno_console_driver.put_char = xeno_console_put_char;
xeno_console_driver.chars_in_buffer = xeno_console_chars_in_buffer;
if ( tty_register_driver(&xeno_console_driver) )
{
printk(KERN_ERR "Couldn't register Xeno console driver\n");
}
else
{
printk("Xeno console successfully installed\n");
}
return 0;
}
void __exit xeno_con_fini(void)
{
int ret;
ret = tty_unregister_driver(&xeno_console_driver);
if ( ret != 0 )
{
printk(KERN_ERR "Unable to unregister Xeno console driver: %d\n", ret);
}
}
module_init(xeno_con_init);
module_exit(xeno_con_fini);
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