mei: bus: add and call callback on notify event

Enable drivers on mei client bus to subscribe
to asynchronous event notifications.
Introduce events_mask to the existing callback infrastructure
so it is possible to handle both RX and event notification.
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/bus.c

@@ -222,7 +222,33 @@ static void mei_bus_event_work(struct work_struct *work)
 	cldev->events = 0;
 
 	/* Prepare for the next read */
-	mei_cl_read_start(cldev->cl, 0, NULL);
+	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX))
+		mei_cl_read_start(cldev->cl, 0, NULL);
+}
+
+/**
+ * mei_cl_bus_notify_event - schedule notify cb on bus client
+ *
+ * @cl: host client
+ */
+void mei_cl_bus_notify_event(struct mei_cl *cl)
+{
+	struct mei_cl_device *cldev = cl->cldev;
+
+	if (!cldev || !cldev->event_cb)
+		return;
+
+	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)))
+		return;
+
+	if (!cl->notify_ev)
+		return;
+
+	set_bit(MEI_CL_EVENT_NOTIF, &cldev->events);
+
+	schedule_work(&cldev->event_work);
+
+	cl->notify_ev = false;
 }
 
 /**
@@ -237,6 +263,9 @@ void mei_cl_bus_rx_event(struct mei_cl *cl)
 	if (!cldev || !cldev->event_cb)
 		return;
 
+	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_RX)))
+		return;
+
 	set_bit(MEI_CL_EVENT_RX, &cldev->events);
 
 	schedule_work(&cldev->event_work);
@@ -247,6 +276,7 @@ void mei_cl_bus_rx_event(struct mei_cl *cl)
  *
  * @cldev: me client devices
  * @event_cb: callback function
+ * @events_mask: requested events bitmask
  * @context: driver context data
  *
  * Return: 0 on success
@@ -254,6 +284,7 @@ void mei_cl_bus_rx_event(struct mei_cl *cl)
  *         <0 on other errors
  */
 int mei_cl_register_event_cb(struct mei_cl_device *cldev,
+			  unsigned long events_mask,
 			  mei_cl_event_cb_t event_cb, void *context)
 {
 	int ret;
@@ -262,13 +293,24 @@ int mei_cl_register_event_cb(struct mei_cl_device *cldev,
 		return -EALREADY;
 
 	cldev->events = 0;
+	cldev->events_mask = events_mask;
 	cldev->event_cb = event_cb;
 	cldev->event_context = context;
 	INIT_WORK(&cldev->event_work, mei_bus_event_work);
 
-	ret = mei_cl_read_start(cldev->cl, 0, NULL);
-	if (ret && ret != -EBUSY)
-		return ret;
+	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
+		ret = mei_cl_read_start(cldev->cl, 0, NULL);
+		if (ret && ret != -EBUSY)
+			return ret;
+	}
+
+	if (cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)) {
+		mutex_lock(&cldev->cl->dev->device_lock);
+		ret = mei_cl_notify_request(cldev->cl, NULL, event_cb ? 1 : 0);
+		mutex_unlock(&cldev->cl->dev->device_lock);
+		if (ret)
+			return ret;
+	}
 
 	return 0;
 }

drivers/misc/mei/client.c

@@ -1375,6 +1375,8 @@ void mei_cl_notify(struct mei_cl *cl)
 
 	if (cl->ev_async)
 		kill_fasync(&cl->ev_async, SIGIO, POLL_PRI);
+
+	mei_cl_bus_notify_event(cl);
 }
 
 /**

drivers/misc/mei/mei_dev.h

@@ -345,6 +345,7 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
 			bool blocking);
 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length);
 void mei_cl_bus_rx_event(struct mei_cl *cl);
+void mei_cl_bus_notify_event(struct mei_cl *cl);
 void mei_cl_bus_remove_devices(struct mei_device *bus);
 int mei_cl_bus_init(void);
 void mei_cl_bus_exit(void);

drivers/nfc/mei_phy.c

@@ -355,7 +355,8 @@ static int nfc_mei_phy_enable(void *phy_id)
 		goto err;
 	}
 
-	r = mei_cl_register_event_cb(phy->device, nfc_mei_event_cb, phy);
+	r = mei_cl_register_event_cb(phy->device, BIT(MEI_CL_EVENT_RX),
+				     nfc_mei_event_cb, phy);
 	if (r) {
 		pr_err("Event cb registration failed %d\n", r);
 		goto err;

include/linux/mei_cl_bus.h

@@ -28,6 +28,7 @@ typedef void (*mei_cl_event_cb_t)(struct mei_cl_device *device,
  * @event_cb: Drivers register this callback to get asynchronous ME
  *	events (e.g. Rx buffer pending) notifications.
  * @event_context: event callback run context
+ * @events_mask: Events bit mask requested by driver.
  * @events: Events bitmask sent to the driver.
  *
  * @do_match: wheather device can be matched with a driver
@@ -46,6 +47,7 @@ struct mei_cl_device {
 	struct work_struct event_work;
 	mei_cl_event_cb_t event_cb;
 	void *event_context;
+	unsigned long events_mask;
 	unsigned long events;
 
 	unsigned int do_match:1;
@@ -76,10 +78,12 @@ ssize_t mei_cl_send(struct mei_cl_device *device, u8 *buf, size_t length);
 ssize_t  mei_cl_recv(struct mei_cl_device *device, u8 *buf, size_t length);
 
 int mei_cl_register_event_cb(struct mei_cl_device *device,
+			  unsigned long event_mask,
 			  mei_cl_event_cb_t read_cb, void *context);
 
 #define MEI_CL_EVENT_RX 0
 #define MEI_CL_EVENT_TX 1
+#define MEI_CL_EVENT_NOTIF 2
 
 void *mei_cl_get_drvdata(const struct mei_cl_device *device);
 void mei_cl_set_drvdata(struct mei_cl_device *device, void *data);