HID: Add Support for Setting and Getting Feature Reports from hidraw

Per the HID Specification, Feature reports must be sent and received on
the Configuration endpoint (EP 0) through the Set_Report/Get_Report
interfaces.  This patch adds two ioctls to hidraw to set and get feature
reports to and from the device.  Modifications were made to hidraw and
usbhid.

New hidraw ioctls:
  HIDIOCSFEATURE - Perform a Set_Report transfer of a Feature report.
  HIDIOCGFEATURE - Perform a Get_Report transfer of a Feature report.

Signed-off-by: Alan Ott <alan@signal11.us>
Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 100 insertions, 6 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 468e87b..8f06044 100644
--- a/drivers/hid/hidraw.c
+++ b/drivers/hid/hidraw.c
@@ -102,15 +102,14 @@ out:
 }
 
 /* the first byte is expected to be a report number */
-static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+/* This function is to be called with the minors_lock mutex held */
+static ssize_t hidraw_send_report(struct file *file, const char __user *buffer, size_t count, unsigned char report_type)
 {
 	unsigned int minor = iminor(file->f_path.dentry->d_inode);
 	struct hid_device *dev;
 	__u8 *buf;
 	int ret = 0;
 
-	mutex_lock(&minors_lock);
-
 	if (!hidraw_table[minor]) {
 		ret = -ENODEV;
 		goto out;
@@ -148,14 +147,92 @@ static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t
 		goto out_free;
 	}
 
-	ret = dev->hid_output_raw_report(dev, buf, count, HID_OUTPUT_REPORT);
+	ret = dev->hid_output_raw_report(dev, buf, count, report_type);
 out_free:
 	kfree(buf);
 out:
+	return ret;
+}
+
+/* the first byte is expected to be a report number */
+static ssize_t hidraw_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
+{
+	ssize_t ret;
+	mutex_lock(&minors_lock);
+	ret = hidraw_send_report(file, buffer, count, HID_OUTPUT_REPORT);
 	mutex_unlock(&minors_lock);
 	return ret;
 }
 
+
+/* This function performs a Get_Report transfer over the control endpoint
+   per section 7.2.1 of the HID specification, version 1.1.  The first byte
+   of buffer is the report number to request, or 0x0 if the defice does not
+   use numbered reports. The report_type parameter can be HID_FEATURE_REPORT
+   or HID_INPUT_REPORT.  This function is to be called with the minors_lock
+   mutex held.  */
+static ssize_t hidraw_get_report(struct file *file, char __user *buffer, size_t count, unsigned char report_type)
+{
+	unsigned int minor = iminor(file->f_path.dentry->d_inode);
+	struct hid_device *dev;
+	__u8 *buf;
+	int ret = 0, len;
+	unsigned char report_number;
+
+	dev = hidraw_table[minor]->hid;
+
+	if (!dev->hid_get_raw_report) {
+		ret = -ENODEV;
+		goto out;
+	}
+
+	if (count > HID_MAX_BUFFER_SIZE) {
+		printk(KERN_WARNING "hidraw: pid %d passed too large report\n",
+				task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (count < 2) {
+		printk(KERN_WARNING "hidraw: pid %d passed too short report\n",
+				task_pid_nr(current));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	buf = kmalloc(count * sizeof(__u8), GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	/* Read the first byte from the user. This is the report number,
+	   which is passed to dev->hid_get_raw_report(). */
+	if (copy_from_user(&report_number, buffer, 1)) {
+		ret = -EFAULT;
+		goto out_free;
+	}
+
+	ret = dev->hid_get_raw_report(dev, report_number, buf, count, report_type);
+
+	if (ret < 0)
+		goto out_free;
+
+	len = (ret < count) ? ret : count;
+
+	if (copy_to_user(buffer, buf, len)) {
+		ret = -EFAULT;
+		goto out_free;
+	}
+
+	ret = len;
+
+out_free:
+	kfree(buf);
+out:
+	return ret;
+}
+
 static unsigned int hidraw_poll(struct file *file, poll_table *wait)
 {
 	struct hidraw_list *list = file->private_data;
@@ -295,7 +372,24 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 		default:
 			{
 				struct hid_device *hid = dev->hid;
-				if (_IOC_TYPE(cmd) != 'H' || _IOC_DIR(cmd) != _IOC_READ) {
+				if (_IOC_TYPE(cmd) != 'H') {
+					ret = -EINVAL;
+					break;
+				}
+
+				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCSFEATURE(0))) {
+					int len = _IOC_SIZE(cmd);
+					ret = hidraw_send_report(file, user_arg, len, HID_FEATURE_REPORT);
+					break;
+				}
+				if (_IOC_NR(cmd) == _IOC_NR(HIDIOCGFEATURE(0))) {
+					int len = _IOC_SIZE(cmd);
+					ret = hidraw_get_report(file, user_arg, len, HID_FEATURE_REPORT);
+					break;
+				}
+
+				/* Begin Read-only ioctls. */
+				if (_IOC_DIR(cmd) != _IOC_READ) {
 					ret = -EINVAL;
 					break;
 				}
@@ -327,7 +421,7 @@ static long hidraw_ioctl(struct file *file, unsigned int cmd,
 						-EFAULT : len;
 					break;
 				}
-		}
+			}
 
 		ret = -ENOTTY;
 	}