1 files changed, 572 insertions, 0 deletions

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
new file mode 100644
index 000000000000..714cd8cc9579
--- /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");