diff options
Diffstat (limited to 'drivers/input/serio/serio_raw.c')
| -rw-r--r-- | drivers/input/serio/serio_raw.c | 444 |
1 files changed, 444 insertions, 0 deletions
diff --git a/drivers/input/serio/serio_raw.c b/drivers/input/serio/serio_raw.c new file mode 100644 index 000000000..17b7fbecd --- /dev/null +++ b/drivers/input/serio/serio_raw.c @@ -0,0 +1,444 @@ +/* + * 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 ? EPOLLHUP | EPOLLERR : EPOLLOUT | EPOLLWRNORM; + if (serio_raw->head != serio_raw->tail) + mask |= EPOLLIN | EPOLLRDNORM; + + 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); |