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>

4 files changed, 141 insertions, 6 deletions

diff --git a/drivers/hid/hidraw.c b/drivers/hid/hidraw.c
index 468e87b53ed2..8f06044a3e3e 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;
         }
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index b336dd84036f..38c261a40c74 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -799,6 +799,40 @@ static int hid_alloc_buffers(struct usb_device *dev, struct hid_device *hid)
         return 0;
 }
 
+static int usbhid_get_raw_report(struct hid_device *hid,
+                unsigned char report_number, __u8 *buf, size_t count,
+                unsigned char report_type)
+{
+        struct usbhid_device *usbhid = hid->driver_data;
+        struct usb_device *dev = hid_to_usb_dev(hid);
+        struct usb_interface *intf = usbhid->intf;
+        struct usb_host_interface *interface = intf->cur_altsetting;
+        int skipped_report_id = 0;
+        int ret;
+
+        /* Byte 0 is the report number. Report data starts at byte 1.*/
+        buf[0] = report_number;
+        if (report_number == 0x0) {
+                /* Offset the return buffer by 1, so that the report ID
+                   will remain in byte 0. */
+                buf++;
+                count--;
+                skipped_report_id = 1;
+        }
+        ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
+                HID_REQ_GET_REPORT,
+                USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE,
+                ((report_type + 1) << 8) | report_number,
+                interface->desc.bInterfaceNumber, buf, count,
+                USB_CTRL_SET_TIMEOUT);
+
+        /* count also the report id */
+        if (ret > 0 && skipped_report_id)
+                ret++;
+
+        return ret;
+}
+
 static int usbhid_output_raw_report(struct hid_device *hid, __u8 *buf, size_t count,
                 unsigned char report_type)
 {
@@ -1139,6 +1173,7 @@ static int usbhid_probe(struct usb_interface *intf, const struct usb_device_id *
 
         usb_set_intfdata(intf, hid);
         hid->ll_driver = &usb_hid_driver;
+        hid->hid_get_raw_report = usbhid_get_raw_report;
         hid->hid_output_raw_report = usbhid_output_raw_report;
         hid->ff_init = hid_pidff_init;
 #ifdef CONFIG_USB_HIDDEV
diff --git a/include/linux/hid.h b/include/linux/hid.h
index d91c25e253c8..e8ee0a93bda3 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -504,6 +504,9 @@ struct hid_device {							/* device report descriptor */
                                   struct hid_usage *, __s32);
         void (*hiddev_report_event) (struct hid_device *, struct hid_report *);
 
+        /* handler for raw input (Get_Report) data, used by hidraw */
+        int (*hid_get_raw_report) (struct hid_device *, unsigned char, __u8 *, size_t, unsigned char);
+
         /* handler for raw output data, used by hidraw */
         int (*hid_output_raw_report) (struct hid_device *, __u8 *, size_t, unsigned char);
 
diff --git a/include/linux/hidraw.h b/include/linux/hidraw.h
index dd8d69269176..4b88e697c4e9 100644
--- a/include/linux/hidraw.h
+++ b/include/linux/hidraw.h
@@ -35,6 +35,9 @@ struct hidraw_devinfo {
 #define HIDIOCGRAWINFO          _IOR('H', 0x03, struct hidraw_devinfo)
 #define HIDIOCGRAWNAME(len)     _IOC(_IOC_READ, 'H', 0x04, len)
 #define HIDIOCGRAWPHYS(len)     _IOC(_IOC_READ, 'H', 0x05, len)
+/* The first byte of SFEATURE and GFEATURE is the report number */
+#define HIDIOCSFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x06, len)
+#define HIDIOCGFEATURE(len)    _IOC(_IOC_WRITE|_IOC_READ, 'H', 0x07, len)
 
 #define HIDRAW_FIRST_MINOR 0
 #define HIDRAW_MAX_DEVICES 64