446 lines
9.9 KiB
C
446 lines
9.9 KiB
C
/*
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* Raw serio device providing access to a raw byte stream from underlying
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* serio port. Closely emulates behavior of pre-2.6 /dev/psaux device
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*
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* Copyright (c) 2004 Dmitry Torokhov
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 as published by
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* the Free Software Foundation.
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*/
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#include <linux/kref.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/poll.h>
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#include <linux/module.h>
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#include <linux/serio.h>
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#include <linux/init.h>
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#include <linux/major.h>
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#include <linux/device.h>
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#include <linux/miscdevice.h>
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#include <linux/wait.h>
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#include <linux/mutex.h>
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#define DRIVER_DESC "Raw serio driver"
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MODULE_AUTHOR("Dmitry Torokhov <dtor@mail.ru>");
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MODULE_DESCRIPTION(DRIVER_DESC);
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MODULE_LICENSE("GPL");
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#define SERIO_RAW_QUEUE_LEN 64
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struct serio_raw {
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unsigned char queue[SERIO_RAW_QUEUE_LEN];
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unsigned int tail, head;
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char name[16];
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struct kref kref;
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struct serio *serio;
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struct miscdevice dev;
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wait_queue_head_t wait;
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struct list_head client_list;
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struct list_head node;
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bool dead;
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};
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struct serio_raw_client {
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struct fasync_struct *fasync;
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struct serio_raw *serio_raw;
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struct list_head node;
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};
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static DEFINE_MUTEX(serio_raw_mutex);
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static LIST_HEAD(serio_raw_list);
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/*********************************************************************
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* Interface with userspace (file operations) *
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*********************************************************************/
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static int serio_raw_fasync(int fd, struct file *file, int on)
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{
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struct serio_raw_client *client = file->private_data;
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return fasync_helper(fd, file, on, &client->fasync);
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}
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static struct serio_raw *serio_raw_locate(int minor)
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{
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struct serio_raw *serio_raw;
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list_for_each_entry(serio_raw, &serio_raw_list, node) {
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if (serio_raw->dev.minor == minor)
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return serio_raw;
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}
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return NULL;
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}
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static int serio_raw_open(struct inode *inode, struct file *file)
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{
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struct serio_raw *serio_raw;
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struct serio_raw_client *client;
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int retval;
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retval = mutex_lock_interruptible(&serio_raw_mutex);
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if (retval)
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return retval;
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serio_raw = serio_raw_locate(iminor(inode));
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if (!serio_raw) {
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retval = -ENODEV;
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goto out;
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}
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if (serio_raw->dead) {
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retval = -ENODEV;
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goto out;
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}
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client = kzalloc(sizeof(struct serio_raw_client), GFP_KERNEL);
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if (!client) {
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retval = -ENOMEM;
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goto out;
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}
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client->serio_raw = serio_raw;
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file->private_data = client;
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kref_get(&serio_raw->kref);
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serio_pause_rx(serio_raw->serio);
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list_add_tail(&client->node, &serio_raw->client_list);
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serio_continue_rx(serio_raw->serio);
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out:
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mutex_unlock(&serio_raw_mutex);
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return retval;
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}
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static void serio_raw_free(struct kref *kref)
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{
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struct serio_raw *serio_raw =
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container_of(kref, struct serio_raw, kref);
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put_device(&serio_raw->serio->dev);
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kfree(serio_raw);
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}
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static int serio_raw_release(struct inode *inode, struct file *file)
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{
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struct serio_raw_client *client = file->private_data;
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struct serio_raw *serio_raw = client->serio_raw;
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serio_pause_rx(serio_raw->serio);
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list_del(&client->node);
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serio_continue_rx(serio_raw->serio);
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kfree(client);
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kref_put(&serio_raw->kref, serio_raw_free);
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return 0;
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}
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static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
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{
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bool empty;
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serio_pause_rx(serio_raw->serio);
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empty = serio_raw->head == serio_raw->tail;
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if (!empty) {
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*c = serio_raw->queue[serio_raw->tail];
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serio_raw->tail = (serio_raw->tail + 1) % SERIO_RAW_QUEUE_LEN;
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}
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serio_continue_rx(serio_raw->serio);
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return !empty;
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}
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static ssize_t serio_raw_read(struct file *file, char __user *buffer,
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size_t count, loff_t *ppos)
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{
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struct serio_raw_client *client = file->private_data;
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struct serio_raw *serio_raw = client->serio_raw;
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char uninitialized_var(c);
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ssize_t read = 0;
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int error;
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for (;;) {
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if (serio_raw->dead)
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return -ENODEV;
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if (serio_raw->head == serio_raw->tail &&
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(file->f_flags & O_NONBLOCK))
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return -EAGAIN;
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if (count == 0)
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break;
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while (read < count && serio_raw_fetch_byte(serio_raw, &c)) {
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if (put_user(c, buffer++))
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return -EFAULT;
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read++;
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}
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if (read)
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break;
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if (!(file->f_flags & O_NONBLOCK)) {
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error = wait_event_interruptible(serio_raw->wait,
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serio_raw->head != serio_raw->tail ||
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serio_raw->dead);
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if (error)
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return error;
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}
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}
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return read;
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}
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static ssize_t serio_raw_write(struct file *file, const char __user *buffer,
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size_t count, loff_t *ppos)
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{
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struct serio_raw_client *client = file->private_data;
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struct serio_raw *serio_raw = client->serio_raw;
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int retval = 0;
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unsigned char c;
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retval = mutex_lock_interruptible(&serio_raw_mutex);
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if (retval)
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return retval;
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if (serio_raw->dead) {
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retval = -ENODEV;
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goto out;
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}
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if (count > 32)
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count = 32;
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while (count--) {
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if (get_user(c, buffer++)) {
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retval = -EFAULT;
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goto out;
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}
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if (serio_write(serio_raw->serio, c)) {
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/* Either signal error or partial write */
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if (retval == 0)
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retval = -EIO;
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goto out;
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}
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retval++;
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}
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out:
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mutex_unlock(&serio_raw_mutex);
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return retval;
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}
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static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
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{
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struct serio_raw_client *client = file->private_data;
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struct serio_raw *serio_raw = client->serio_raw;
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unsigned int mask;
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poll_wait(file, &serio_raw->wait, wait);
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mask = serio_raw->dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM;
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if (serio_raw->head != serio_raw->tail)
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mask |= POLLIN | POLLRDNORM;
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return mask;
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}
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static const struct file_operations serio_raw_fops = {
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.owner = THIS_MODULE,
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.open = serio_raw_open,
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.release = serio_raw_release,
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.read = serio_raw_read,
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.write = serio_raw_write,
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.poll = serio_raw_poll,
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.fasync = serio_raw_fasync,
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.llseek = noop_llseek,
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};
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/*********************************************************************
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* Interface with serio port *
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*********************************************************************/
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static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
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unsigned int dfl)
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{
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struct serio_raw *serio_raw = serio_get_drvdata(serio);
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struct serio_raw_client *client;
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unsigned int head = serio_raw->head;
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/* we are holding serio->lock here so we are protected */
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serio_raw->queue[head] = data;
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head = (head + 1) % SERIO_RAW_QUEUE_LEN;
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if (likely(head != serio_raw->tail)) {
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serio_raw->head = head;
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list_for_each_entry(client, &serio_raw->client_list, node)
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kill_fasync(&client->fasync, SIGIO, POLL_IN);
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wake_up_interruptible(&serio_raw->wait);
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}
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return IRQ_HANDLED;
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}
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static int serio_raw_connect(struct serio *serio, struct serio_driver *drv)
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{
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static atomic_t serio_raw_no = ATOMIC_INIT(0);
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struct serio_raw *serio_raw;
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int err;
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serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL);
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if (!serio_raw) {
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dev_dbg(&serio->dev, "can't allocate memory for a device\n");
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return -ENOMEM;
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}
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snprintf(serio_raw->name, sizeof(serio_raw->name),
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"serio_raw%ld", (long)atomic_inc_return(&serio_raw_no) - 1);
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kref_init(&serio_raw->kref);
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INIT_LIST_HEAD(&serio_raw->client_list);
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init_waitqueue_head(&serio_raw->wait);
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serio_raw->serio = serio;
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get_device(&serio->dev);
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serio_set_drvdata(serio, serio_raw);
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err = serio_open(serio, drv);
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if (err)
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goto err_free;
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err = mutex_lock_killable(&serio_raw_mutex);
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if (err)
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goto err_close;
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list_add_tail(&serio_raw->node, &serio_raw_list);
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mutex_unlock(&serio_raw_mutex);
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serio_raw->dev.minor = PSMOUSE_MINOR;
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serio_raw->dev.name = serio_raw->name;
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serio_raw->dev.parent = &serio->dev;
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serio_raw->dev.fops = &serio_raw_fops;
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err = misc_register(&serio_raw->dev);
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if (err) {
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serio_raw->dev.minor = MISC_DYNAMIC_MINOR;
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err = misc_register(&serio_raw->dev);
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}
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if (err) {
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dev_err(&serio->dev,
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"failed to register raw access device for %s\n",
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serio->phys);
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goto err_unlink;
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}
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dev_info(&serio->dev, "raw access enabled on %s (%s, minor %d)\n",
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serio->phys, serio_raw->name, serio_raw->dev.minor);
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return 0;
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err_unlink:
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list_del_init(&serio_raw->node);
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err_close:
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serio_close(serio);
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err_free:
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serio_set_drvdata(serio, NULL);
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kref_put(&serio_raw->kref, serio_raw_free);
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return err;
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}
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static int serio_raw_reconnect(struct serio *serio)
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{
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struct serio_raw *serio_raw = serio_get_drvdata(serio);
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struct serio_driver *drv = serio->drv;
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if (!drv || !serio_raw) {
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dev_dbg(&serio->dev,
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"reconnect request, but serio is disconnected, ignoring...\n");
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return -1;
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}
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/*
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* Nothing needs to be done here, we just need this method to
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* keep the same device.
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*/
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return 0;
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}
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/*
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* Wake up users waiting for IO so they can disconnect from
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* dead device.
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*/
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static void serio_raw_hangup(struct serio_raw *serio_raw)
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{
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struct serio_raw_client *client;
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serio_pause_rx(serio_raw->serio);
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list_for_each_entry(client, &serio_raw->client_list, node)
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kill_fasync(&client->fasync, SIGIO, POLL_HUP);
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serio_continue_rx(serio_raw->serio);
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wake_up_interruptible(&serio_raw->wait);
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}
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static void serio_raw_disconnect(struct serio *serio)
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{
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struct serio_raw *serio_raw = serio_get_drvdata(serio);
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misc_deregister(&serio_raw->dev);
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mutex_lock(&serio_raw_mutex);
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serio_raw->dead = true;
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list_del_init(&serio_raw->node);
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mutex_unlock(&serio_raw_mutex);
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serio_raw_hangup(serio_raw);
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serio_close(serio);
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kref_put(&serio_raw->kref, serio_raw_free);
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serio_set_drvdata(serio, NULL);
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}
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static struct serio_device_id serio_raw_serio_ids[] = {
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{
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.type = SERIO_8042,
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.proto = SERIO_ANY,
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.id = SERIO_ANY,
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.extra = SERIO_ANY,
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},
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{
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.type = SERIO_8042_XL,
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.proto = SERIO_ANY,
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.id = SERIO_ANY,
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.extra = SERIO_ANY,
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},
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{ 0 }
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};
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MODULE_DEVICE_TABLE(serio, serio_raw_serio_ids);
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static struct serio_driver serio_raw_drv = {
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.driver = {
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.name = "serio_raw",
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},
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.description = DRIVER_DESC,
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.id_table = serio_raw_serio_ids,
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.interrupt = serio_raw_interrupt,
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.connect = serio_raw_connect,
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.reconnect = serio_raw_reconnect,
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.disconnect = serio_raw_disconnect,
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.manual_bind = true,
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};
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module_serio_driver(serio_raw_drv);
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