--- /dev/null
+/*
+ * 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 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);
Code Review / kvmfornfv.git / blobdiff