2 files changed, 136 insertions, 1 deletions

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 421c492dc824..ea560bfa033d 100644
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -42,6 +42,12 @@ struct uhid_device {
         __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;
@@ -143,7 +149,84 @@ static int uhid_hid_parse(struct hid_device *hid)
 static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
                             __u8 *buf, size_t count, unsigned char rtype)
 {
-        return 0;
+        struct uhid_device *uhid = hid->driver_data;
+        __u8 report_type;
+        struct uhid_event *ev;
+        unsigned long flags;
+        int ret;
+        size_t 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,
@@ -265,7 +348,11 @@ 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);
@@ -284,6 +371,31 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev)
         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;
@@ -293,9 +405,12 @@ static int uhid_char_open(struct inode *inode, struct file *file)
                 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);
@@ -398,6 +513,9 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
         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;
         }
diff --git a/include/linux/uhid.h b/include/linux/uhid.h
index 2c972550a624..9c6974f16966 100644
--- a/include/linux/uhid.h
+++ b/include/linux/uhid.h
@@ -32,6 +32,8 @@ enum uhid_event_type {
         UHID_OUTPUT,
         UHID_OUTPUT_EV,
         UHID_INPUT,
+        UHID_FEATURE,
+        UHID_FEATURE_ANSWER,
 };
 
 struct uhid_create_req {
@@ -73,6 +75,19 @@ struct uhid_output_ev_req {
         __s32 value;
 } __attribute__((__packed__));
 
+struct uhid_feature_req {
+        __u32 id;
+        __u8 rnum;
+        __u8 rtype;
+} __attribute__((__packed__));
+
+struct uhid_feature_answer_req {
+        __u32 id;
+        __u16 err;
+        __u16 size;
+        __u8 data[UHID_DATA_MAX];
+};
+
 struct uhid_event {
         __u32 type;
 
@@ -81,6 +96,8 @@ struct uhid_event {
                 struct uhid_input_req input;
                 struct uhid_output_req output;
                 struct uhid_output_ev_req output_ev;
+                struct uhid_feature_req feature;
+                struct uhid_feature_answer_req feature_answer;
         } u;
 } __attribute__((__packed__));