linux/drivers/macintosh/ans-lcd.c
Thomas Gleixner 95fdac7372 macintosh: Remove BKL from ans-lcd
The ans-lcd driver got the cycle_kernel_lock() in anslcd_open() from
the BKL pushdown and it still uses the locked ioctl.

The BKL serialization in this driver is more than obscure and
definitely does not cover all possible corner cases. Protect the
access to the hardware with a local mutex and get rid of BKL and
locked ioctl.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <20091010153349.966159859@linutronix.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-14 17:36:50 +02:00

202 lines
3.9 KiB
C

/*
* /dev/lcd driver for Apple Network Servers.
*/
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/fcntl.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <asm/sections.h>
#include <asm/prom.h>
#include <asm/io.h>
#include "ans-lcd.h"
#define ANSLCD_ADDR 0xf301c000
#define ANSLCD_CTRL_IX 0x00
#define ANSLCD_DATA_IX 0x10
static unsigned long anslcd_short_delay = 80;
static unsigned long anslcd_long_delay = 3280;
static volatile unsigned char __iomem *anslcd_ptr;
static DEFINE_MUTEX(anslcd_mutex);
#undef DEBUG
static void
anslcd_write_byte_ctrl ( unsigned char c )
{
#ifdef DEBUG
printk(KERN_DEBUG "LCD: CTRL byte: %02x\n",c);
#endif
out_8(anslcd_ptr + ANSLCD_CTRL_IX, c);
switch(c) {
case 1:
case 2:
case 3:
udelay(anslcd_long_delay); break;
default: udelay(anslcd_short_delay);
}
}
static void
anslcd_write_byte_data ( unsigned char c )
{
out_8(anslcd_ptr + ANSLCD_DATA_IX, c);
udelay(anslcd_short_delay);
}
static ssize_t
anslcd_write( struct file * file, const char __user * buf,
size_t count, loff_t *ppos )
{
const char __user *p = buf;
int i;
#ifdef DEBUG
printk(KERN_DEBUG "LCD: write\n");
#endif
if (!access_ok(VERIFY_READ, buf, count))
return -EFAULT;
mutex_lock(&anslcd_mutex);
for ( i = *ppos; count > 0; ++i, ++p, --count )
{
char c;
__get_user(c, p);
anslcd_write_byte_data( c );
}
mutex_unlock(&anslcd_mutex);
*ppos = i;
return p - buf;
}
static long
anslcd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
char ch, __user *temp;
long ret = 0;
#ifdef DEBUG
printk(KERN_DEBUG "LCD: ioctl(%d,%d)\n",cmd,arg);
#endif
mutex_lock(&anslcd_mutex);
switch ( cmd )
{
case ANSLCD_CLEAR:
anslcd_write_byte_ctrl ( 0x38 );
anslcd_write_byte_ctrl ( 0x0f );
anslcd_write_byte_ctrl ( 0x06 );
anslcd_write_byte_ctrl ( 0x01 );
anslcd_write_byte_ctrl ( 0x02 );
break;
case ANSLCD_SENDCTRL:
temp = (char __user *) arg;
__get_user(ch, temp);
for (; ch; temp++) { /* FIXME: This is ugly, but should work, as a \0 byte is not a valid command code */
anslcd_write_byte_ctrl ( ch );
__get_user(ch, temp);
}
break;
case ANSLCD_SETSHORTDELAY:
if (!capable(CAP_SYS_ADMIN))
ret =-EACCES;
else
anslcd_short_delay=arg;
break;
case ANSLCD_SETLONGDELAY:
if (!capable(CAP_SYS_ADMIN))
ret = -EACCES;
else
anslcd_long_delay=arg;
break;
default:
ret = -EINVAL;
}
mutex_unlock(&anslcd_mutex);
return ret;
}
static int
anslcd_open( struct inode * inode, struct file * file )
{
return 0;
}
const struct file_operations anslcd_fops = {
.write = anslcd_write,
.unlocked_ioctl = anslcd_ioctl,
.open = anslcd_open,
};
static struct miscdevice anslcd_dev = {
ANSLCD_MINOR,
"anslcd",
&anslcd_fops
};
const char anslcd_logo[] = "********************" /* Line #1 */
"* LINUX! *" /* Line #3 */
"* Welcome to *" /* Line #2 */
"********************"; /* Line #4 */
static int __init
anslcd_init(void)
{
int a;
int retval;
struct device_node* node;
node = of_find_node_by_name(NULL, "lcd");
if (!node || !node->parent || strcmp(node->parent->name, "gc")) {
of_node_put(node);
return -ENODEV;
}
of_node_put(node);
anslcd_ptr = ioremap(ANSLCD_ADDR, 0x20);
retval = misc_register(&anslcd_dev);
if(retval < 0){
printk(KERN_INFO "LCD: misc_register failed\n");
iounmap(anslcd_ptr);
return retval;
}
#ifdef DEBUG
printk(KERN_DEBUG "LCD: init\n");
#endif
mutex_lock(&anslcd_mutex);
anslcd_write_byte_ctrl ( 0x38 );
anslcd_write_byte_ctrl ( 0x0c );
anslcd_write_byte_ctrl ( 0x06 );
anslcd_write_byte_ctrl ( 0x01 );
anslcd_write_byte_ctrl ( 0x02 );
for(a=0;a<80;a++) {
anslcd_write_byte_data(anslcd_logo[a]);
}
mutex_unlock(&anslcd_mutex);
return 0;
}
static void __exit
anslcd_exit(void)
{
misc_deregister(&anslcd_dev);
iounmap(anslcd_ptr);
}
module_init(anslcd_init);
module_exit(anslcd_exit);