summaryrefslogtreecommitdiffstats
path: root/drivers/hid/hid-wiimote.h
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/hid/hid-wiimote.h')
-rw-r--r--drivers/hid/hid-wiimote.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/drivers/hid/hid-wiimote.h b/drivers/hid/hid-wiimote.h
index 301607da7715..34417021606e 100644
--- a/drivers/hid/hid-wiimote.h
+++ b/drivers/hid/hid-wiimote.h
@@ -195,6 +195,16 @@ static inline void wiimote_cmd_complete(struct wiimote_data *wdata)
complete(&wdata->state.ready);
}
+/* requires the state.lock spinlock to be held */
+static inline void wiimote_cmd_abort(struct wiimote_data *wdata)
+{
+ /* Abort synchronous request by waking up the sleeping caller. But
+ * reset the state.cmd field to an invalid value so no further event
+ * handlers will work with it. */
+ wdata->state.cmd = WIIPROTO_REQ_MAX;
+ complete(&wdata->state.ready);
+}
+
static inline int wiimote_cmd_acquire(struct wiimote_data *wdata)
{
return mutex_lock_interruptible(&wdata->state.sync) ? -ERESTARTSYS : 0;
@@ -223,11 +233,17 @@ static inline int wiimote_cmd_wait(struct wiimote_data *wdata)
{
int ret;
+ /* The completion acts as implicit memory barrier so we can safely
+ * assume that state.cmd is set on success/failure and isn't accessed
+ * by any other thread, anymore. */
+
ret = wait_for_completion_interruptible_timeout(&wdata->state.ready, HZ);
if (ret < 0)
return -ERESTARTSYS;
else if (ret == 0)
return -EIO;
+ else if (wdata->state.cmd != WIIPROTO_REQ_NULL)
+ return -EIO;
else
return 0;
}
@@ -236,9 +252,12 @@ static inline int wiimote_cmd_wait_noint(struct wiimote_data *wdata)
{
unsigned long ret;
+ /* no locking needed; see wiimote_cmd_wait() */
ret = wait_for_completion_timeout(&wdata->state.ready, HZ);
if (!ret)
return -EIO;
+ else if (wdata->state.cmd != WIIPROTO_REQ_NULL)
+ return -EIO;
else
return 0;
}