/* * 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 unsigned int 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; unsigned int 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);