4 files changed, 41 insertions, 7 deletions

diff --git a/drivers/misc/mei/bus-fixup.c b/drivers/misc/mei/bus-fixup.c
index 7f2cef9011ae..18e05ca7584f 100644
--- a/drivers/misc/mei/bus-fixup.c
+++ b/drivers/misc/mei/bus-fixup.c
@@ -141,7 +141,7 @@ static int mei_osver(struct mei_cl_device *cldev)
         if (ret < 0)
                 return ret;
 
-        ret = __mei_cl_recv(cldev->cl, buf, length);
+        ret = __mei_cl_recv(cldev->cl, buf, length, 0);
         if (ret < 0)
                 return ret;
 
@@ -272,7 +272,7 @@ static int mei_nfc_if_version(struct mei_cl *cl,
                 return -ENOMEM;
 
         ret = 0;
-        bytes_recv = __mei_cl_recv(cl, (u8 *)reply, if_version_length);
+        bytes_recv = __mei_cl_recv(cl, (u8 *)reply, if_version_length, 0);
         if (bytes_recv < if_version_length) {
                 dev_err(bus->dev, "Could not read IF version\n");
                 ret = -EIO;
diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 2fd254ecde2f..0037153c80a6 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -98,15 +98,18 @@ out:
  * @cl: host client
  * @buf: buffer to receive
  * @length: buffer length
+ * @mode: io mode
  *
  * Return: read size in bytes of < 0 on error
  */
-ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
+ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
+                      unsigned int mode)
 {
         struct mei_device *bus;
         struct mei_cl_cb *cb;
         size_t r_length;
         ssize_t rets;
+        bool nonblock = !!(mode & MEI_CL_IO_RX_NONBLOCK);
 
         if (WARN_ON(!cl || !cl->dev))
                 return -ENODEV;
@@ -127,6 +130,11 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
         if (rets && rets != -EBUSY)
                 goto out;
 
+        if (nonblock) {
+                rets = -EAGAIN;
+                goto out;
+        }
+
         /* wait on event only if there is no other waiter */
         /* synchronized under device mutex */
         if (!waitqueue_active(&cl->rx_wait)) {
@@ -192,6 +200,25 @@ ssize_t mei_cldev_send(struct mei_cl_device *cldev, u8 *buf, size_t length)
 EXPORT_SYMBOL_GPL(mei_cldev_send);
 
 /**
+ * mei_cldev_recv_nonblock - non block client receive (read)
+ *
+ * @cldev: me client device
+ * @buf: buffer to receive
+ * @length: buffer length
+ *
+ * Return: read size in bytes of < 0 on error
+ *         -EAGAIN if function will block.
+ */
+ssize_t mei_cldev_recv_nonblock(struct mei_cl_device *cldev, u8 *buf,
+                                size_t length)
+{
+        struct mei_cl *cl = cldev->cl;
+
+        return __mei_cl_recv(cl, buf, length, MEI_CL_IO_RX_NONBLOCK);
+}
+EXPORT_SYMBOL_GPL(mei_cldev_recv_nonblock);
+
+/**
  * mei_cldev_recv - client receive (read)
  *
  * @cldev: me client device
@@ -204,7 +231,7 @@ ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length)
 {
         struct mei_cl *cl = cldev->cl;
 
-        return __mei_cl_recv(cl, buf, length);
+        return __mei_cl_recv(cl, buf, length, 0);
 }
 EXPORT_SYMBOL_GPL(mei_cldev_recv);
 
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 0e94df517410..699693cd8c59 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -115,10 +115,14 @@ enum mei_cb_file_ops {
  *
  * @MEI_CL_IO_TX_BLOCKING: send is blocking
  * @MEI_CL_IO_TX_INTERNAL: internal communication between driver and FW
+ *
+ * @MEI_CL_IO_RX_NONBLOCK: recv is non-blocking
  */
 enum mei_cl_io_mode {
         MEI_CL_IO_TX_BLOCKING = BIT(0),
         MEI_CL_IO_TX_INTERNAL = BIT(1),
+
+        MEI_CL_IO_RX_NONBLOCK = BIT(2),
 };
 
 /*
@@ -319,7 +323,8 @@ void mei_cl_bus_rescan_work(struct work_struct *work);
 void mei_cl_bus_dev_fixup(struct mei_cl_device *dev);
 ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
                       unsigned int mode);
-ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length);
+ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length,
+                      unsigned int mode);
 bool mei_cl_bus_rx_event(struct mei_cl *cl);
 bool mei_cl_bus_notify_event(struct mei_cl *cl);
 void mei_cl_bus_remove_devices(struct mei_device *bus);
diff --git a/include/linux/mei_cl_bus.h b/include/linux/mei_cl_bus.h
index 017f5232b3de..a0d274fe08f1 100644
--- a/include/linux/mei_cl_bus.h
+++ b/include/linux/mei_cl_bus.h
@@ -75,7 +75,7 @@ void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv);
 /**
  * module_mei_cl_driver - Helper macro for registering mei cl driver
  *
- * @__mei_cldrv mei_cl_driver structure
+ * @__mei_cldrv: mei_cl_driver structure
  *
  *  Helper macro for mei cl drivers which do not do anything special in module
  *  init/exit, for eliminating a boilerplate code.
@@ -86,7 +86,9 @@ void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv);
                       mei_cldev_driver_unregister)
 
 ssize_t mei_cldev_send(struct mei_cl_device *cldev, u8 *buf, size_t length);
-ssize_t  mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length);
+ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length);
+ssize_t mei_cldev_recv_nonblock(struct mei_cl_device *cldev, u8 *buf,
+                                size_t length);
 
 int mei_cldev_register_rx_cb(struct mei_cl_device *cldev, mei_cldev_cb_t rx_cb);
 int mei_cldev_register_notif_cb(struct mei_cl_device *cldev,