diff options
Diffstat (limited to 'drivers/char/pc110pad.c')
| -rw-r--r-- | drivers/char/pc110pad.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/drivers/char/pc110pad.c b/drivers/char/pc110pad.c index 0c00dcfa5..7e4518e15 100644 --- a/drivers/char/pc110pad.c +++ b/drivers/char/pc110pad.c @@ -30,6 +30,8 @@ #include <asm/signal.h> #include <asm/io.h> #include <asm/irq.h> +#include <asm/semaphore.h> +#include <linux/spinlock.h> #include <asm/uaccess.h> #include "pc110pad.h" @@ -51,7 +53,7 @@ static struct pc110pad_params current_params; static wait_queue_head_t queue; static struct fasync_struct *asyncptr; static int active=0; /* number of concurrent open()s */ - +static struct semaphore read_lock; /* * Utility to reset a timer to go off some time in the future. @@ -75,7 +77,7 @@ static void wake_readers(void) { wake_up_interruptible(&queue); if(asyncptr) - kill_fasync(asyncptr, SIGIO); + kill_fasync(asyncptr, SIGIO, POLL_IN); } @@ -503,10 +505,13 @@ static int close_pad(struct inode * inode, struct file * file) */ static int open_pad(struct inode * inode, struct file * file) { + unsigned long flags; + if (active++) return 0; MOD_INC_USE_COUNT; + save_flags(flags); cli(); outb(0x30, current_params.io+2); /* switch off digitiser */ pad_irq(0,0,0); /* read to flush any pending bytes */ @@ -522,7 +527,7 @@ static int open_pad(struct inode * inode, struct file * file) synthesize_tap=0; del_timer(&bounce_timer); del_timer(&tap_timer); - sti(); + restore_flags(flags); return 0; } @@ -556,14 +561,19 @@ static ssize_t read_pad(struct file * file, char * buffer, size_t count, loff_t { int r; + down(&read_lock); for(r=0; r<count; r++) { if(!read_byte_count) new_sample(read_bytes); if(put_user(read_bytes[read_byte_count], buffer+r)) - return -EFAULT; + { + r = -EFAULT; + break; + } read_byte_count = (read_byte_count+1)%3; } + up(&read_lock); return r; } @@ -681,6 +691,7 @@ static void pc110pad_unload(void) int init_module(void) { + init_MUTEX(&read_lock); return pc110pad_init(); } |