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441 lines
9.7 KiB
441 lines
9.7 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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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#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/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 <[email protected]>"); |
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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 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 __poll_t 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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__poll_t mask; |
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poll_wait(file, &serio_raw->wait, wait); |
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mask = serio_raw->dead ? EPOLLHUP | EPOLLERR : EPOLLOUT | EPOLLWRNORM; |
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if (serio_raw->head != serio_raw->tail) |
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mask |= EPOLLIN | EPOLLRDNORM; |
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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(-1); |
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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)); |
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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 const 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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