kernel-ark/drivers/input/serio/serio_raw.c
Arjan van de Ven 2b8693c061 [PATCH] mark struct file_operations const 3
Many struct file_operations in the kernel can be "const".  Marking them const
moves these to the .rodata section, which avoids false sharing with potential
dirty data.  In addition it'll catch accidental writes at compile time to
these shared resources.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-12 09:48:45 -08:00

402 lines
9.0 KiB
C

/*
* Raw serio device providing access to a raw byte stream from underlying
* serio port. Closely emulates behavior of pre-2.6 /dev/psaux device
*
* Copyright (c) 2004 Dmitry Torokhov
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/slab.h>
#include <linux/poll.h>
#include <linux/module.h>
#include <linux/serio.h>
#include <linux/init.h>
#include <linux/major.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/wait.h>
#include <linux/mutex.h>
#define DRIVER_DESC "Raw serio driver"
MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
#define SERIO_RAW_QUEUE_LEN 64
struct serio_raw {
unsigned char queue[SERIO_RAW_QUEUE_LEN];
unsigned int tail, head;
char name[16];
unsigned int refcnt;
struct serio *serio;
struct miscdevice dev;
wait_queue_head_t wait;
struct list_head list;
struct list_head node;
};
struct serio_raw_list {
struct fasync_struct *fasync;
struct serio_raw *serio_raw;
struct list_head node;
};
static DEFINE_MUTEX(serio_raw_mutex);
static LIST_HEAD(serio_raw_list);
static unsigned int serio_raw_no;
/*********************************************************************
* Interface with userspace (file operations) *
*********************************************************************/
static int serio_raw_fasync(int fd, struct file *file, int on)
{
struct serio_raw_list *list = file->private_data;
int retval;
retval = fasync_helper(fd, file, on, &list->fasync);
return retval < 0 ? retval : 0;
}
static struct serio_raw *serio_raw_locate(int minor)
{
struct serio_raw *serio_raw;
list_for_each_entry(serio_raw, &serio_raw_list, node) {
if (serio_raw->dev.minor == minor)
return serio_raw;
}
return NULL;
}
static int serio_raw_open(struct inode *inode, struct file *file)
{
struct serio_raw *serio_raw;
struct serio_raw_list *list;
int retval = 0;
retval = mutex_lock_interruptible(&serio_raw_mutex);
if (retval)
return retval;
if (!(serio_raw = serio_raw_locate(iminor(inode)))) {
retval = -ENODEV;
goto out;
}
if (!serio_raw->serio) {
retval = -ENODEV;
goto out;
}
if (!(list = kzalloc(sizeof(struct serio_raw_list), GFP_KERNEL))) {
retval = -ENOMEM;
goto out;
}
list->serio_raw = serio_raw;
file->private_data = list;
serio_raw->refcnt++;
list_add_tail(&list->node, &serio_raw->list);
out:
mutex_unlock(&serio_raw_mutex);
return retval;
}
static int serio_raw_cleanup(struct serio_raw *serio_raw)
{
if (--serio_raw->refcnt == 0) {
misc_deregister(&serio_raw->dev);
list_del_init(&serio_raw->node);
kfree(serio_raw);
return 1;
}
return 0;
}
static int serio_raw_release(struct inode *inode, struct file *file)
{
struct serio_raw_list *list = file->private_data;
struct serio_raw *serio_raw = list->serio_raw;
mutex_lock(&serio_raw_mutex);
serio_raw_fasync(-1, file, 0);
serio_raw_cleanup(serio_raw);
mutex_unlock(&serio_raw_mutex);
return 0;
}
static int serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
{
unsigned long flags;
int empty;
spin_lock_irqsave(&serio_raw->serio->lock, flags);
empty = serio_raw->head == serio_raw->tail;
if (!empty) {
*c = serio_raw->queue[serio_raw->tail];
serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
}
spin_unlock_irqrestore(&serio_raw->serio->lock, flags);
return !empty;
}
static ssize_t serio_raw_read(struct file *file, char __user *buffer, size_t count, loff_t *ppos)
{
struct serio_raw_list *list = file->private_data;
struct serio_raw *serio_raw = list->serio_raw;
char c;
ssize_t retval = 0;
if (!serio_raw->serio)
return -ENODEV;
if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK))
return -EAGAIN;
retval = wait_event_interruptible(list->serio_raw->wait,
serio_raw->head != serio_raw->tail || !serio_raw->serio);
if (retval)
return retval;
if (!serio_raw->serio)
return -ENODEV;
while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
if (put_user(c, buffer++))
return -EFAULT;
retval++;
}
return retval;
}
static ssize_t serio_raw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
struct serio_raw_list *list = file->private_data;
ssize_t written = 0;
int retval;
unsigned char c;
retval = mutex_lock_interruptible(&serio_raw_mutex);
if (retval)
return retval;
if (!list->serio_raw->serio) {
retval = -ENODEV;
goto out;
}
if (count > 32)
count = 32;
while (count--) {
if (get_user(c, buffer++)) {
retval = -EFAULT;
goto out;
}
if (serio_write(list->serio_raw->serio, c)) {
retval = -EIO;
goto out;
}
written++;
};
out:
mutex_unlock(&serio_raw_mutex);
return written;
}
static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
{
struct serio_raw_list *list = file->private_data;
poll_wait(file, &list->serio_raw->wait, wait);
if (list->serio_raw->head != list->serio_raw->tail)
return POLLIN | POLLRDNORM;
return 0;
}
static const struct file_operations serio_raw_fops = {
.owner = THIS_MODULE,
.open = serio_raw_open,
.release = serio_raw_release,
.read = serio_raw_read,
.write = serio_raw_write,
.poll = serio_raw_poll,
.fasync = serio_raw_fasync,
};
/*********************************************************************
* Interface with serio port *
*********************************************************************/
static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
unsigned int dfl)
{
struct serio_raw *serio_raw = serio_get_drvdata(serio);
struct serio_raw_list *list;
unsigned int head = serio_raw->head;
/* we are holding serio->lock here so we are prootected */
serio_raw->queue[head] = data;
head = (head + 1) % SERIO_RAW_QUEUE_LEN;
if (likely(head != serio_raw->tail)) {
serio_raw->head = head;
list_for_each_entry(list, &serio_raw->list, node)
kill_fasync(&list->fasync, SIGIO, POLL_IN);
wake_up_interruptible(&serio_raw->wait);
}
return IRQ_HANDLED;
}
static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
{
struct serio_raw *serio_raw;
int err;
if (!(serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL))) {
printk(KERN_ERR "serio_raw.c: can't allocate memory for a device\n");
return -ENOMEM;
}
mutex_lock(&serio_raw_mutex);
snprintf(serio_raw->name, sizeof(serio_raw->name), "serio_raw%d", serio_raw_no++);
serio_raw->refcnt = 1;
serio_raw->serio = serio;
INIT_LIST_HEAD(&serio_raw->list);
init_waitqueue_head(&serio_raw->wait);
serio_set_drvdata(serio, serio_raw);
err = serio_open(serio, drv);
if (err)
goto out_free;
list_add_tail(&serio_raw->node, &serio_raw_list);
serio_raw->dev.minor = PSMOUSE_MINOR;
serio_raw->dev.name = serio_raw->name;
serio_raw->dev.parent = &serio->dev;
serio_raw->dev.fops = &serio_raw_fops;
err = misc_register(&serio_raw->dev);
if (err) {
serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
err = misc_register(&serio_raw->dev);
}
if (err) {
printk(KERN_INFO "serio_raw: failed to register raw access device for %s\n",
serio->phys);
goto out_close;
}
printk(KERN_INFO "serio_raw: raw access enabled on %s (%s, minor %d)\n",
serio->phys, serio_raw->name, serio_raw->dev.minor);
goto out;
out_close:
serio_close(serio);
list_del_init(&serio_raw->node);
out_free:
serio_set_drvdata(serio, NULL);
kfree(serio_raw);
out:
mutex_unlock(&serio_raw_mutex);
return err;
}
static int serio_raw_reconnect(struct serio *serio)
{
struct serio_raw *serio_raw = serio_get_drvdata(serio);
struct serio_driver *drv = serio->drv;
if (!drv || !serio_raw) {
printk(KERN_DEBUG "serio_raw: reconnect request, but serio is disconnected, ignoring...\n");
return -1;
}
/*
* Nothing needs to be done here, we just need this method to
* keep the same device.
*/
return 0;
}
static void serio_raw_disconnect(struct serio *serio)
{
struct serio_raw *serio_raw;
mutex_lock(&serio_raw_mutex);
serio_raw = serio_get_drvdata(serio);
serio_close(serio);
serio_set_drvdata(serio, NULL);
serio_raw->serio = NULL;
if (!serio_raw_cleanup(serio_raw))
wake_up_interruptible(&serio_raw->wait);
mutex_unlock(&serio_raw_mutex);
}
static struct serio_device_id serio_raw_serio_ids[] = {
{
.type = SERIO_8042,
.proto = SERIO_ANY,
.id = SERIO_ANY,
.extra = SERIO_ANY,
},
{ 0 }
};
MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
static struct serio_driver serio_raw_drv = {
.driver = {
.name = "serio_raw",
},
.description = DRIVER_DESC,
.id_table = serio_raw_serio_ids,
.interrupt = serio_raw_interrupt,
.connect = serio_raw_connect,
.reconnect = serio_raw_reconnect,
.disconnect = serio_raw_disconnect,
.manual_bind = 1,
};
static int __init serio_raw_init(void)
{
return serio_register_driver(&serio_raw_drv);
}
static void __exit serio_raw_exit(void)
{
serio_unregister_driver(&serio_raw_drv);
}
module_init(serio_raw_init);
module_exit(serio_raw_exit);