[PATCH 40/47] Add serio_raw driver

Vojtech Pavlik
2004-07-29T14:17:09Z

ChangeSet@1.1757.15.35, 2004-06-29 01:31:03-05:00, dtor_core@ameritech.net
Input: Add serio_raw driver that binds to serio ports and provides
unobstructed access to the underlying serio port via a char
device. The driver tries to register char device 10,1
(/dev/psaux) first and if it fails goes for dynamically
allocated minor. To bind use sysfs interface:

echo -n "serio_raw" > /sys/bus/serio/devices/serioX/driver

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

Kconfig | 16 ++
Makefile | 1
serio_raw.c | 390 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 407 insertions(+)

===================================================================

diff -Nru a/drivers/input/serio/Kconfig b/drivers/input/serio/Kconfig
--- a/drivers/input/serio/Kconfig Thu Jul 29 14:39:02 2004
+++ b/drivers/input/serio/Kconfig Thu Jul 29 14:39:02 2004
@@ -130,3 +130,19 @@

To compile this driver as a module, choose M here: the
module will be called maceps2.
+
+config SERIO_RAW
+ tristate "Raw access to serio ports"
+ depends on SERIO
+ help
+ Say Y here if you want to have raw access to serio ports, such as
+ AUX ports on i8042 keyboard controller. Each serio port that is
+ bound to this driver will be accessible via a char device with
+ major 10 and dynamically allocated minor. The driver will try
+ allocating minor 1 (that historically corresponds to /dev/psaux)
+ first. To bind this driver to a serio port use sysfs interface:
+
+ echo -n "serio_raw" > /sys/bus/serio/devices/serioX/driver
+
+ To compile this driver as a module, choose M here: the
+ module will be called serio_raw.
diff -Nru a/drivers/input/serio/Makefile b/drivers/input/serio/Makefile
--- a/drivers/input/serio/Makefile Thu Jul 29 14:39:02 2004
+++ b/drivers/input/serio/Makefile Thu Jul 29 14:39:02 2004
@@ -17,3 +17,4 @@
obj-$(CONFIG_SERIO_GSCPS2) += gscps2.o
obj-$(CONFIG_SERIO_PCIPS2) += pcips2.o
obj-$(CONFIG_SERIO_MACEPS2) += maceps2.o
+obj-$(CONFIG_SERIO_RAW) += serio_raw.o
diff -Nru a/drivers/input/serio/serio_raw.c b/drivers/input/serio/serio_raw.c
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/drivers/input/serio/serio_raw.c Thu Jul 29 14:39:02 2004
@@ -0,0 +1,390 @@
+/*
+ * 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/slab.h>
+#include <linux/poll.h>
+#include <linux/module.h>
+#include <linux/serio.h>
+#include <linux/init.h>
+#include <linux/major.h>
+#include <linux/device.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/miscdevice.h>
+#include <linux/wait.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];
+ unsigned int refcnt;
+ struct serio *serio;
+ struct miscdevice dev;
+ wait_queue_head_t wait;
+ struct list_head list;
+ struct list_head node;
+};
+
+struct serio_raw_list {
+ struct fasync_struct *fasync;
+ struct serio_raw *serio_raw;
+ struct list_head node;
+};
+
+static DECLARE_MUTEX(serio_raw_sem);
+static LIST_HEAD(serio_raw_list);
+static unsigned int serio_raw_no;
+
+/*********************************************************************
+ * Interface with userspace (file operations) *
+ *********************************************************************/
+
+static int serio_raw_fasync(int fd, struct file *file, int on)
+{
+ struct serio_raw_list *list = file->private_data;
+ int retval;
+
+ retval = fasync_helper(fd, file, on, &list->fasync);
+ return retval < 0 ? retval : 0;
+}
+
+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_list *list;
+ int retval = 0;
+
+ retval = down_interruptible(&serio_raw_sem);
+ if (retval)
+ return retval;
+
+ if (!(serio_raw = serio_raw_locate(iminor(inode)))) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ if (!serio_raw->serio) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ if (!(list = kmalloc(sizeof(struct serio_raw_list), GFP_KERNEL))) {
+ retval = -ENOMEM;
+ goto out;
+ }
+
+ memset(list, 0, sizeof(struct serio_raw_list));
+ list->serio_raw = serio_raw;
+ file->private_data = list;
+
+ serio_raw->refcnt++;
+ list_add_tail(&list->node, &serio_raw->list);
+
+out:
+ up(&serio_raw_sem);
+ return retval;
+}
+
+static int serio_raw_cleanup(struct serio_raw *serio_raw)
+{
+ if (--serio_raw->refcnt == 0) {
+ misc_deregister(&serio_raw->dev);
+ list_del_init(&serio_raw->node);
+ kfree(serio_raw);
+
+ return 1;
+ }
+
+ return 0;
+}
+
+static int serio_raw_release(struct inode *inode, struct file *file)
+{
+ struct serio_raw_list *list = file->private_data;
+ struct serio_raw *serio_raw = list->serio_raw;
+
+ down(&serio_raw_sem);
+
+ serio_raw_fasync(-1, file, 0);
+ serio_raw_cleanup(serio_raw);
+
+ up(&serio_raw_sem);
+ return 0;
+}
+
+static int serio_raw_fetch_byte(struct serio_raw *serio_raw, char *c)
+{
+ unsigned long flags;
+ int empty;
+
+ spin_lock_irqsave(&serio_raw->serio->lock, flags);
+
+ 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;
+ }
+
+ spin_unlock_irqrestore(&serio_raw->serio->lock, flags);
+
+ return !empty;
+}
+
+static ssize_t serio_raw_read(struct file *file, char *buffer, size_t count, loff_t *ppos)
+{
+ struct serio_raw_list *list = file->private_data;
+ struct serio_raw *serio_raw = list->serio_raw;
+ char c;
+ ssize_t retval = 0;
+
+ if (!serio_raw->serio)
+ return -ENODEV;
+
+ if (serio_raw->head == serio_raw->tail && (file->f_flags & O_NONBLOCK))
+ return -EAGAIN;
+
+ retval = wait_event_interruptible(list->serio_raw->wait,
+ serio_raw->head != serio_raw->tail || !serio_raw->serio);
+ if (retval)
+ return retval;
+
+ if (!serio_raw->serio)
+ return -ENODEV;
+
+ while (retval < count && serio_raw_fetch_byte(serio_raw, &c)) {
+ if (put_user(c, buffer++))
+ return -EFAULT;
+ retval++;
+ }
+
+ return retval;
+}
+
+static ssize_t serio_raw_write(struct file *file, const char *buffer, size_t count, loff_t *ppos)
+{
+ struct serio_raw_list *list = file->private_data;
+ ssize_t written = 0;
+ int retval;
+ unsigned char c;
+
+ retval = down_interruptible(&serio_raw_sem);
+ if (retval)
+ return retval;
+
+ if (!list->serio_raw->serio) {
+ retval = -ENODEV;
+ goto out;
+ }
+
+ if (count > 32)
+ count = 32;
+
+ while (count--) {
+ if (get_user(c, buffer++)) {
+ retval = -EFAULT;
+ goto out;
+ }
+ if (serio_write(list->serio_raw->serio, c)) {
+ retval = -EIO;
+ goto out;
+ }
+ written++;
+ };
+
+out:
+ up(&serio_raw_sem);
+ return written;
+}
+
+static unsigned int serio_raw_poll(struct file *file, poll_table *wait)
+{
+ struct serio_raw_list *list = file->private_data;
+
+ poll_wait(file, &list->serio_raw->wait, wait);
+
+ if (list->serio_raw->head != list->serio_raw->tail)
+ return POLLIN | POLLRDNORM;
+
+ return 0;
+}
+
+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,
+};
+
+
+/*********************************************************************
+ * Interface with serio port *
+ *********************************************************************/
+
+static irqreturn_t serio_raw_interrupt(struct serio *serio, unsigned char data,
+ unsigned int dfl, struct pt_regs *regs)
+{
+ struct serio_raw *serio_raw = serio->private;
+ struct serio_raw_list *list;
+ unsigned int head = serio_raw->head;
+
+ /* we are holding serio->lock here so we are prootected */
+ 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(list, &serio_raw->list, node)
+ kill_fasync(&list->fasync, SIGIO, POLL_IN);
+ wake_up_interruptible(&serio_raw->wait);
+ }
+
+ return IRQ_HANDLED;
+}
+
+static void serio_raw_connect(struct serio *serio, struct serio_driver *drv)
+{
+ struct serio_raw *serio_raw;
+ int err;
+
+ if ((serio->type & SERIO_TYPE) != SERIO_8042)
+ return;
+
+ if (!(serio_raw = kmalloc(sizeof(struct serio_raw), GFP_KERNEL))) {
+ printk(KERN_ERR "serio_raw.c: can't allocate memory for a device\n");
+ return;
+ }
+
+ down(&serio_raw_sem);
+
+ memset(serio_raw, 0, sizeof(struct serio_raw));
+ snprintf(serio_raw->name, sizeof(serio_raw->name), "serio_raw%d", serio_raw_no++);
+ serio_raw->refcnt = 1;
+ serio_raw->serio = serio;
+ INIT_LIST_HEAD(&serio_raw->list);
+ init_waitqueue_head(&serio_raw->wait);
+
+ serio->private = serio_raw;
+ if (serio_open(serio, drv))
+ goto out_free;
+
+ list_add_tail(&serio_raw->node, &serio_raw_list);
+
+ serio_raw->dev.minor = PSMOUSE_MINOR;
+ serio_raw->dev.name = serio_raw->name;
+ 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) {
+ printk(KERN_INFO "serio_raw: failed to register raw access device for %s\n",
+ serio->phys);
+ goto out_close;
+ }
+
+ printk(KERN_INFO "serio_raw: raw access enabled on %s (%s, minor %d)\n",
+ serio->phys, serio_raw->name, serio_raw->dev.minor);
+ goto out;
+
+out_close:
+ serio_close(serio);
+ list_del_init(&serio_raw->node);
+out_free:
+ serio->private = NULL;
+ kfree(serio_raw);
+out:
+ up(&serio_raw_sem);
+}
+
+static int serio_raw_reconnect(struct serio *serio)
+{
+ struct serio_raw *serio_raw = serio->private;
+ struct serio_driver *drv = serio->drv;
+
+ if (!drv || !serio_raw) {
+ printk(KERN_DEBUG "serio_raw: 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;
+}
+
+static void serio_raw_disconnect(struct serio *serio)
+{
+ struct serio_raw *serio_raw;
+
+ down(&serio_raw_sem);
+
+ serio_raw = serio->private;
+
+ serio_close(serio);
+ serio->private = NULL;
+
+ serio_raw->serio = NULL;
+ if (!serio_raw_cleanup(serio_raw))
+ wake_up_interruptible(&serio_raw->wait);
+
+ up(&serio_raw_sem);
+}
+
+static struct serio_driver serio_raw_drv = {
+ .driver = {
+ .name = "serio_raw",
+ },
+ .description = DRIVER_DESC,
+ .interrupt = serio_raw_interrupt,
+ .connect = serio_raw_connect,
+ .reconnect = serio_raw_reconnect,
+ .disconnect = serio_raw_disconnect,
+ .manual_bind = 1,
+};
+
+int __init serio_raw_init(void)
+{
+ serio_register_driver(&serio_raw_drv);
+ return 0;
+}
+
+void __exit serio_raw_exit(void)
+{
+ serio_unregister_driver(&serio_raw_drv);
+}
+
+module_init(serio_raw_init);
+module_exit(serio_raw_exit);