| /* |
| * 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/kref.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/poll.h> |
| #include <linux/module.h> |
| #include <linux/serio.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]; |
| struct kref kref; |
| struct serio *serio; |
| struct miscdevice dev; |
| wait_queue_head_t wait; |
| struct list_head client_list; |
| struct list_head node; |
| bool dead; |
| }; |
| |
| struct serio_raw_client { |
| 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); |
| |
| /********************************************************************* |
| * Interface with userspace (file operations) * |
| *********************************************************************/ |
| |
| static int serio_raw_fasync(int fd, struct file *file, int on) |
| { |
| struct serio_raw_client *client = file->private_data; |
| |
| return fasync_helper(fd, file, on, &client->fasync); |
| } |
| |
| 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_client *client; |
| int retval; |
| |
| retval = mutex_lock_interruptible(&serio_raw_mutex); |
| if (retval) |
| return retval; |
| |
| serio_raw = serio_raw_locate(iminor(inode)); |
| if (!serio_raw) { |
| retval = -ENODEV; |
| goto out; |
| } |
| |
| if (serio_raw->dead) { |
| retval = -ENODEV; |
| goto out; |
| } |
| |
| client = kzalloc(sizeof(struct serio_raw_client), GFP_KERNEL); |
| if (!client) { |
| retval = -ENOMEM; |
| goto out; |
| } |
| |
| client->serio_raw = serio_raw; |
| file->private_data = client; |
| |
| kref_get(&serio_raw->kref); |
| |
| serio_pause_rx(serio_raw->serio); |
| list_add_tail(&client->node, &serio_raw->client_list); |
| serio_continue_rx(serio_raw->serio); |
| |
| out: |
| mutex_unlock(&serio_raw_mutex); |
| return retval; |
| } |
| |
| static void serio_raw_free(struct kref *kref) |
| { |
| struct serio_raw *serio_raw = |
| container_of(kref, struct serio_raw, kref); |
| |
| put_device(&serio_raw->serio->dev); |
| kfree(serio_raw); |
| } |
| |
| static int serio_raw_release(struct inode *inode, struct file *file) |
| { |
| struct serio_raw_client *client = file->private_data; |
| struct serio_raw *serio_raw = client->serio_raw; |
| |
| serio_pause_rx(serio_raw->serio); |
| list_del(&client->node); |
| serio_continue_rx(serio_raw->serio); |
| |
| kfree(client); |
| |
| kref_put(&serio_raw->kref, serio_raw_free); |
| |
| return 0; |
| } |
| |
| static bool serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c) |
| { |
| bool empty; |
| |
| serio_pause_rx(serio_raw->serio); |
| |
| 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; |
| } |
| |
| serio_continue_rx(serio_raw->serio); |
| |
| return !empty; |
| } |
| |
| static ssize_t serio_raw_read(struct file *file, char __user *buffer, |
| size_t count, loff_t *ppos) |
| { |
| struct serio_raw_client *client = file->private_data; |
| struct serio_raw *serio_raw = client->serio_raw; |
| char uninitialized_var(c); |
| ssize_t read = 0; |
| int error; |
| |
| for (;;) { |
| if (serio_raw->dead) |
| return -ENODEV; |
| |
| if (serio_raw->head == serio_raw->tail && |
| (file->f_flags & O_NONBLOCK)) |
| return -EAGAIN; |
| |
| if (count == 0) |
| break; |
| |
| while (read < count && serio_raw_fetch_byte(serio_raw, &c)) { |
| if (put_user(c, buffer++)) |
| return -EFAULT; |
| read++; |
| } |
| |
| if (read) |
| break; |
| |
| if (!(file->f_flags & O_NONBLOCK)) { |
| error = wait_event_interruptible(serio_raw->wait, |
| serio_raw->head != serio_raw->tail || |
| serio_raw->dead); |
| if (error) |
| return error; |
| } |
| } |
| |
| return read; |
| } |
| |
| static ssize_t serio_raw_write(struct file *file, const char __user *buffer, |
| size_t count, loff_t *ppos) |
| { |
| struct serio_raw_client *client = file->private_data; |
| struct serio_raw *serio_raw = client->serio_raw; |
| int retval = 0; |
| unsigned char c; |
| |
| retval = mutex_lock_interruptible(&serio_raw_mutex); |
| if (retval) |
| return retval; |
| |
| if (serio_raw->dead) { |
| retval = -ENODEV; |
| goto out; |
| } |
| |
| if (count > 32) |
| count = 32; |
| |
| while (count--) { |
| if (get_user(c, buffer++)) { |
| retval = -EFAULT; |
| goto out; |
| } |
| |
| if (serio_write(serio_raw->serio, c)) { |
| /* Either signal error or partial write */ |
| if (retval == 0) |
| retval = -EIO; |
| goto out; |
| } |
| |
| retval++; |
| } |
| |
| out: |
| mutex_unlock(&serio_raw_mutex); |
| return retval; |
| } |
| |
| static __poll_t serio_raw_poll(struct file *file, poll_table *wait) |
| { |
| struct serio_raw_client *client = file->private_data; |
| struct serio_raw *serio_raw = client->serio_raw; |
| __poll_t mask; |
| |
| poll_wait(file, &serio_raw->wait, wait); |
| |
| mask = serio_raw->dead ? POLLHUP | POLLERR : POLLOUT | POLLWRNORM; |
| if (serio_raw->head != serio_raw->tail) |
| mask |= POLLIN | POLLRDNORM; |
| |
| return mask; |
| } |
| |
| 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, |
| .llseek = noop_llseek, |
| }; |
| |
| |
| /********************************************************************* |
| * 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_client *client; |
| unsigned int head = serio_raw->head; |
| |
| /* we are holding serio->lock here so we are protected */ |
| 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(client, &serio_raw->client_list, node) |
| kill_fasync(&client->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) |
| { |
| static atomic_t serio_raw_no = ATOMIC_INIT(-1); |
| struct serio_raw *serio_raw; |
| int err; |
| |
| serio_raw = kzalloc(sizeof(struct serio_raw), GFP_KERNEL); |
| if (!serio_raw) { |
| dev_dbg(&serio->dev, "can't allocate memory for a device\n"); |
| return -ENOMEM; |
| } |
| |
| snprintf(serio_raw->name, sizeof(serio_raw->name), |
| "serio_raw%ld", (long)atomic_inc_return(&serio_raw_no)); |
| kref_init(&serio_raw->kref); |
| INIT_LIST_HEAD(&serio_raw->client_list); |
| init_waitqueue_head(&serio_raw->wait); |
| |
| serio_raw->serio = serio; |
| get_device(&serio->dev); |
| |
| serio_set_drvdata(serio, serio_raw); |
| |
| err = serio_open(serio, drv); |
| if (err) |
| goto err_free; |
| |
| err = mutex_lock_killable(&serio_raw_mutex); |
| if (err) |
| goto err_close; |
| |
| list_add_tail(&serio_raw->node, &serio_raw_list); |
| mutex_unlock(&serio_raw_mutex); |
| |
| 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) { |
| dev_err(&serio->dev, |
| "failed to register raw access device for %s\n", |
| serio->phys); |
| goto err_unlink; |
| } |
| |
| dev_info(&serio->dev, "raw access enabled on %s (%s, minor %d)\n", |
| serio->phys, serio_raw->name, serio_raw->dev.minor); |
| return 0; |
| |
| err_unlink: |
| list_del_init(&serio_raw->node); |
| err_close: |
| serio_close(serio); |
| err_free: |
| serio_set_drvdata(serio, NULL); |
| kref_put(&serio_raw->kref, serio_raw_free); |
| 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) { |
| dev_dbg(&serio->dev, |
| "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; |
| } |
| |
| /* |
| * Wake up users waiting for IO so they can disconnect from |
| * dead device. |
| */ |
| static void serio_raw_hangup(struct serio_raw *serio_raw) |
| { |
| struct serio_raw_client *client; |
| |
| serio_pause_rx(serio_raw->serio); |
| list_for_each_entry(client, &serio_raw->client_list, node) |
| kill_fasync(&client->fasync, SIGIO, POLL_HUP); |
| serio_continue_rx(serio_raw->serio); |
| |
| wake_up_interruptible(&serio_raw->wait); |
| } |
| |
| |
| static void serio_raw_disconnect(struct serio *serio) |
| { |
| struct serio_raw *serio_raw = serio_get_drvdata(serio); |
| |
| misc_deregister(&serio_raw->dev); |
| |
| mutex_lock(&serio_raw_mutex); |
| serio_raw->dead = true; |
| list_del_init(&serio_raw->node); |
| mutex_unlock(&serio_raw_mutex); |
| |
| serio_raw_hangup(serio_raw); |
| |
| serio_close(serio); |
| kref_put(&serio_raw->kref, serio_raw_free); |
| |
| serio_set_drvdata(serio, NULL); |
| } |
| |
| static const struct serio_device_id serio_raw_serio_ids[] = { |
| { |
| .type = SERIO_8042, |
| .proto = SERIO_ANY, |
| .id = SERIO_ANY, |
| .extra = SERIO_ANY, |
| }, |
| { |
| .type = SERIO_8042_XL, |
| .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 = true, |
| }; |
| |
| module_serio_driver(serio_raw_drv); |