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path: root/drivers/hid/uhid.c
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Diffstat (limited to 'drivers/hid/uhid.c')
-rw-r--r--drivers/hid/uhid.c572
1 files changed, 572 insertions, 0 deletions
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
new file mode 100644
index 00000000000..714cd8cc957
--- /dev/null
+++ b/drivers/hid/uhid.c
@@ -0,0 +1,572 @@
+/*
+ * User-space I/O driver support for HID subsystem
+ * Copyright (c) 2012 David Herrmann
+ */
+
+/*
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ */
+
+#include <linux/atomic.h>
+#include <linux/device.h>
+#include <linux/fs.h>
+#include <linux/hid.h>
+#include <linux/input.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/poll.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/uhid.h>
+#include <linux/wait.h>
+
+#define UHID_NAME "uhid"
+#define UHID_BUFSIZE 32
+
+struct uhid_device {
+ struct mutex devlock;
+ bool running;
+
+ __u8 *rd_data;
+ uint rd_size;
+
+ struct hid_device *hid;
+ struct uhid_event input_buf;
+
+ wait_queue_head_t waitq;
+ spinlock_t qlock;
+ __u8 head;
+ __u8 tail;
+ struct uhid_event *outq[UHID_BUFSIZE];
+
+ struct mutex report_lock;
+ wait_queue_head_t report_wait;
+ atomic_t report_done;
+ atomic_t report_id;
+ struct uhid_event report_buf;
+};
+
+static struct miscdevice uhid_misc;
+
+static void uhid_queue(struct uhid_device *uhid, struct uhid_event *ev)
+{
+ __u8 newhead;
+
+ newhead = (uhid->head + 1) % UHID_BUFSIZE;
+
+ if (newhead != uhid->tail) {
+ uhid->outq[uhid->head] = ev;
+ uhid->head = newhead;
+ wake_up_interruptible(&uhid->waitq);
+ } else {
+ hid_warn(uhid->hid, "Output queue is full\n");
+ kfree(ev);
+ }
+}
+
+static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
+{
+ unsigned long flags;
+ struct uhid_event *ev;
+
+ ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+ if (!ev)
+ return -ENOMEM;
+
+ ev->type = event;
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+ uhid_queue(uhid, ev);
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+
+ return 0;
+}
+
+static int uhid_hid_start(struct hid_device *hid)
+{
+ struct uhid_device *uhid = hid->driver_data;
+
+ return uhid_queue_event(uhid, UHID_START);
+}
+
+static void uhid_hid_stop(struct hid_device *hid)
+{
+ struct uhid_device *uhid = hid->driver_data;
+
+ hid->claimed = 0;
+ uhid_queue_event(uhid, UHID_STOP);
+}
+
+static int uhid_hid_open(struct hid_device *hid)
+{
+ struct uhid_device *uhid = hid->driver_data;
+
+ return uhid_queue_event(uhid, UHID_OPEN);
+}
+
+static void uhid_hid_close(struct hid_device *hid)
+{
+ struct uhid_device *uhid = hid->driver_data;
+
+ uhid_queue_event(uhid, UHID_CLOSE);
+}
+
+static int uhid_hid_input(struct input_dev *input, unsigned int type,
+ unsigned int code, int value)
+{
+ struct hid_device *hid = input_get_drvdata(input);
+ struct uhid_device *uhid = hid->driver_data;
+ unsigned long flags;
+ struct uhid_event *ev;
+
+ ev = kzalloc(sizeof(*ev), GFP_ATOMIC);
+ if (!ev)
+ return -ENOMEM;
+
+ ev->type = UHID_OUTPUT_EV;
+ ev->u.output_ev.type = type;
+ ev->u.output_ev.code = code;
+ ev->u.output_ev.value = value;
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+ uhid_queue(uhid, ev);
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+
+ return 0;
+}
+
+static int uhid_hid_parse(struct hid_device *hid)
+{
+ struct uhid_device *uhid = hid->driver_data;
+
+ return hid_parse_report(hid, uhid->rd_data, uhid->rd_size);
+}
+
+static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
+ __u8 *buf, size_t count, unsigned char rtype)
+{
+ struct uhid_device *uhid = hid->driver_data;
+ __u8 report_type;
+ struct uhid_event *ev;
+ unsigned long flags;
+ int ret;
+ size_t uninitialized_var(len);
+ struct uhid_feature_answer_req *req;
+
+ if (!uhid->running)
+ return -EIO;
+
+ switch (rtype) {
+ case HID_FEATURE_REPORT:
+ report_type = UHID_FEATURE_REPORT;
+ break;
+ case HID_OUTPUT_REPORT:
+ report_type = UHID_OUTPUT_REPORT;
+ break;
+ case HID_INPUT_REPORT:
+ report_type = UHID_INPUT_REPORT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = mutex_lock_interruptible(&uhid->report_lock);
+ if (ret)
+ return ret;
+
+ ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+ if (!ev) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+ ev->type = UHID_FEATURE;
+ ev->u.feature.id = atomic_inc_return(&uhid->report_id);
+ ev->u.feature.rnum = rnum;
+ ev->u.feature.rtype = report_type;
+
+ atomic_set(&uhid->report_done, 0);
+ uhid_queue(uhid, ev);
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+
+ ret = wait_event_interruptible_timeout(uhid->report_wait,
+ atomic_read(&uhid->report_done), 5 * HZ);
+
+ /*
+ * Make sure "uhid->running" is cleared on shutdown before
+ * "uhid->report_done" is set.
+ */
+ smp_rmb();
+ if (!ret || !uhid->running) {
+ ret = -EIO;
+ } else if (ret < 0) {
+ ret = -ERESTARTSYS;
+ } else {
+ spin_lock_irqsave(&uhid->qlock, flags);
+ req = &uhid->report_buf.u.feature_answer;
+
+ if (req->err) {
+ ret = -EIO;
+ } else {
+ ret = 0;
+ len = min(count,
+ min_t(size_t, req->size, UHID_DATA_MAX));
+ memcpy(buf, req->data, len);
+ }
+
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+ }
+
+ atomic_set(&uhid->report_done, 1);
+
+unlock:
+ mutex_unlock(&uhid->report_lock);
+ return ret ? ret : len;
+}
+
+static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
+ unsigned char report_type)
+{
+ struct uhid_device *uhid = hid->driver_data;
+ __u8 rtype;
+ unsigned long flags;
+ struct uhid_event *ev;
+
+ switch (report_type) {
+ case HID_FEATURE_REPORT:
+ rtype = UHID_FEATURE_REPORT;
+ break;
+ case HID_OUTPUT_REPORT:
+ rtype = UHID_OUTPUT_REPORT;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (count < 1 || count > UHID_DATA_MAX)
+ return -EINVAL;
+
+ ev = kzalloc(sizeof(*ev), GFP_KERNEL);
+ if (!ev)
+ return -ENOMEM;
+
+ ev->type = UHID_OUTPUT;
+ ev->u.output.size = count;
+ ev->u.output.rtype = rtype;
+ memcpy(ev->u.output.data, buf, count);
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+ uhid_queue(uhid, ev);
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+
+ return count;
+}
+
+static struct hid_ll_driver uhid_hid_driver = {
+ .start = uhid_hid_start,
+ .stop = uhid_hid_stop,
+ .open = uhid_hid_open,
+ .close = uhid_hid_close,
+ .hidinput_input_event = uhid_hid_input,
+ .parse = uhid_hid_parse,
+};
+
+static int uhid_dev_create(struct uhid_device *uhid,
+ const struct uhid_event *ev)
+{
+ struct hid_device *hid;
+ int ret;
+
+ if (uhid->running)
+ return -EALREADY;
+
+ uhid->rd_size = ev->u.create.rd_size;
+ if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
+ return -EINVAL;
+
+ uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
+ if (!uhid->rd_data)
+ return -ENOMEM;
+
+ if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
+ uhid->rd_size)) {
+ ret = -EFAULT;
+ goto err_free;
+ }
+
+ hid = hid_allocate_device();
+ if (IS_ERR(hid)) {
+ ret = PTR_ERR(hid);
+ goto err_free;
+ }
+
+ strncpy(hid->name, ev->u.create.name, 127);
+ hid->name[127] = 0;
+ strncpy(hid->phys, ev->u.create.phys, 63);
+ hid->phys[63] = 0;
+ strncpy(hid->uniq, ev->u.create.uniq, 63);
+ hid->uniq[63] = 0;
+
+ hid->ll_driver = &uhid_hid_driver;
+ hid->hid_get_raw_report = uhid_hid_get_raw;
+ hid->hid_output_raw_report = uhid_hid_output_raw;
+ hid->bus = ev->u.create.bus;
+ hid->vendor = ev->u.create.vendor;
+ hid->product = ev->u.create.product;
+ hid->version = ev->u.create.version;
+ hid->country = ev->u.create.country;
+ hid->driver_data = uhid;
+ hid->dev.parent = uhid_misc.this_device;
+
+ uhid->hid = hid;
+ uhid->running = true;
+
+ ret = hid_add_device(hid);
+ if (ret) {
+ hid_err(hid, "Cannot register HID device\n");
+ goto err_hid;
+ }
+
+ return 0;
+
+err_hid:
+ hid_destroy_device(hid);
+ uhid->hid = NULL;
+ uhid->running = false;
+err_free:
+ kfree(uhid->rd_data);
+ return ret;
+}
+
+static int uhid_dev_destroy(struct uhid_device *uhid)
+{
+ if (!uhid->running)
+ return -EINVAL;
+
+ /* clear "running" before setting "report_done" */
+ uhid->running = false;
+ smp_wmb();
+ atomic_set(&uhid->report_done, 1);
+ wake_up_interruptible(&uhid->report_wait);
+
+ hid_destroy_device(uhid->hid);
+ kfree(uhid->rd_data);
+
+ return 0;
+}
+
+static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
+{
+ if (!uhid->running)
+ return -EINVAL;
+
+ hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input.data,
+ min_t(size_t, ev->u.input.size, UHID_DATA_MAX), 0);
+
+ return 0;
+}
+
+static int uhid_dev_feature_answer(struct uhid_device *uhid,
+ struct uhid_event *ev)
+{
+ unsigned long flags;
+
+ if (!uhid->running)
+ return -EINVAL;
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+
+ /* id for old report; drop it silently */
+ if (atomic_read(&uhid->report_id) != ev->u.feature_answer.id)
+ goto unlock;
+ if (atomic_read(&uhid->report_done))
+ goto unlock;
+
+ memcpy(&uhid->report_buf, ev, sizeof(*ev));
+ atomic_set(&uhid->report_done, 1);
+ wake_up_interruptible(&uhid->report_wait);
+
+unlock:
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+ return 0;
+}
+
+static int uhid_char_open(struct inode *inode, struct file *file)
+{
+ struct uhid_device *uhid;
+
+ uhid = kzalloc(sizeof(*uhid), GFP_KERNEL);
+ if (!uhid)
+ return -ENOMEM;
+
+ mutex_init(&uhid->devlock);
+ mutex_init(&uhid->report_lock);
+ spin_lock_init(&uhid->qlock);
+ init_waitqueue_head(&uhid->waitq);
+ init_waitqueue_head(&uhid->report_wait);
+ uhid->running = false;
+ atomic_set(&uhid->report_done, 1);
+
+ file->private_data = uhid;
+ nonseekable_open(inode, file);
+
+ return 0;
+}
+
+static int uhid_char_release(struct inode *inode, struct file *file)
+{
+ struct uhid_device *uhid = file->private_data;
+ unsigned int i;
+
+ uhid_dev_destroy(uhid);
+
+ for (i = 0; i < UHID_BUFSIZE; ++i)
+ kfree(uhid->outq[i]);
+
+ kfree(uhid);
+
+ return 0;
+}
+
+static ssize_t uhid_char_read(struct file *file, char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct uhid_device *uhid = file->private_data;
+ int ret;
+ unsigned long flags;
+ size_t len;
+
+ /* they need at least the "type" member of uhid_event */
+ if (count < sizeof(__u32))
+ return -EINVAL;
+
+try_again:
+ if (file->f_flags & O_NONBLOCK) {
+ if (uhid->head == uhid->tail)
+ return -EAGAIN;
+ } else {
+ ret = wait_event_interruptible(uhid->waitq,
+ uhid->head != uhid->tail);
+ if (ret)
+ return ret;
+ }
+
+ ret = mutex_lock_interruptible(&uhid->devlock);
+ if (ret)
+ return ret;
+
+ if (uhid->head == uhid->tail) {
+ mutex_unlock(&uhid->devlock);
+ goto try_again;
+ } else {
+ len = min(count, sizeof(**uhid->outq));
+ if (copy_to_user(buffer, uhid->outq[uhid->tail], len)) {
+ ret = -EFAULT;
+ } else {
+ kfree(uhid->outq[uhid->tail]);
+ uhid->outq[uhid->tail] = NULL;
+
+ spin_lock_irqsave(&uhid->qlock, flags);
+ uhid->tail = (uhid->tail + 1) % UHID_BUFSIZE;
+ spin_unlock_irqrestore(&uhid->qlock, flags);
+ }
+ }
+
+ mutex_unlock(&uhid->devlock);
+ return ret ? ret : len;
+}
+
+static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ struct uhid_device *uhid = file->private_data;
+ int ret;
+ size_t len;
+
+ /* we need at least the "type" member of uhid_event */
+ if (count < sizeof(__u32))
+ return -EINVAL;
+
+ ret = mutex_lock_interruptible(&uhid->devlock);
+ if (ret)
+ return ret;
+
+ memset(&uhid->input_buf, 0, sizeof(uhid->input_buf));
+ len = min(count, sizeof(uhid->input_buf));
+ if (copy_from_user(&uhid->input_buf, buffer, len)) {
+ ret = -EFAULT;
+ goto unlock;
+ }
+
+ switch (uhid->input_buf.type) {
+ case UHID_CREATE:
+ ret = uhid_dev_create(uhid, &uhid->input_buf);
+ break;
+ case UHID_DESTROY:
+ ret = uhid_dev_destroy(uhid);
+ break;
+ case UHID_INPUT:
+ ret = uhid_dev_input(uhid, &uhid->input_buf);
+ break;
+ case UHID_FEATURE_ANSWER:
+ ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
+ break;
+ default:
+ ret = -EOPNOTSUPP;
+ }
+
+unlock:
+ mutex_unlock(&uhid->devlock);
+
+ /* return "count" not "len" to not confuse the caller */
+ return ret ? ret : count;
+}
+
+static unsigned int uhid_char_poll(struct file *file, poll_table *wait)
+{
+ struct uhid_device *uhid = file->private_data;
+
+ poll_wait(file, &uhid->waitq, wait);
+
+ if (uhid->head != uhid->tail)
+ return POLLIN | POLLRDNORM;
+
+ return 0;
+}
+
+static const struct file_operations uhid_fops = {
+ .owner = THIS_MODULE,
+ .open = uhid_char_open,
+ .release = uhid_char_release,
+ .read = uhid_char_read,
+ .write = uhid_char_write,
+ .poll = uhid_char_poll,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice uhid_misc = {
+ .fops = &uhid_fops,
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = UHID_NAME,
+};
+
+static int __init uhid_init(void)
+{
+ return misc_register(&uhid_misc);
+}
+
+static void __exit uhid_exit(void)
+{
+ misc_deregister(&uhid_misc);
+}
+
+module_init(uhid_init);
+module_exit(uhid_exit);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("David Herrmann <dh.herrmann@gmail.com>");
+MODULE_DESCRIPTION("User-space I/O driver support for HID subsystem");