Date:   Wed, 16 Nov 2016 22:51:29 +0200
From:   Tomas Winkler <tomas.winkler@...el.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     Alexander Usyskin <alexander.usyskin@...el.com>,
        linux-kernel@...r.kernel.org,
        Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc-next 3/4] mei: bus: split RX and async notification callbacks

From: Alexander Usyskin <alexander.usyskin@...el.com>

Split callbacks for RX and async notification events on mei bus to
eliminate synchronization problems and to open way for RX optimizations.

Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/bus.c     | 141 ++++++++++++++++++++++++++-------------------
 drivers/misc/mei/client.c  |   5 ++
 drivers/nfc/mei_phy.c      |  36 +++++-------
 drivers/watchdog/mei_wdt.c |  36 ++++--------
 include/linux/mei_cl_bus.h |  32 +++++-----
 5 files changed, 128 insertions(+), 122 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 483587f60249..2fd254ecde2f 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -209,31 +209,40 @@ ssize_t mei_cldev_recv(struct mei_cl_device *cldev, u8 *buf, size_t length)
 EXPORT_SYMBOL_GPL(mei_cldev_recv);
 
 /**
- * mei_cl_bus_event_work  - dispatch rx event for a bus device
- *    and schedule new work
+ * mei_cl_bus_rx_work - dispatch rx event for a bus device
  *
  * @work: work
  */
-static void mei_cl_bus_event_work(struct work_struct *work)
+static void mei_cl_bus_rx_work(struct work_struct *work)
 {
 	struct mei_cl_device *cldev;
 	struct mei_device *bus;
 
-	cldev = container_of(work, struct mei_cl_device, event_work);
+	cldev = container_of(work, struct mei_cl_device, rx_work);
 
 	bus = cldev->bus;
 
-	if (cldev->event_cb)
-		cldev->event_cb(cldev, cldev->events);
+	if (cldev->rx_cb)
+		cldev->rx_cb(cldev);
 
-	cldev->events = 0;
+	mutex_lock(&bus->device_lock);
+	mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
+	mutex_unlock(&bus->device_lock);
+}
 
-	/* Prepare for the next read */
-	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
-		mutex_lock(&bus->device_lock);
-		mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
-		mutex_unlock(&bus->device_lock);
-	}
+/**
+ * mei_cl_bus_notif_work - dispatch FW notif event for a bus device
+ *
+ * @work: work
+ */
+static void mei_cl_bus_notif_work(struct work_struct *work)
+{
+	struct mei_cl_device *cldev;
+
+	cldev = container_of(work, struct mei_cl_device, notif_work);
+
+	if (cldev->notif_cb)
+		cldev->notif_cb(cldev);
 }
 
 /**
@@ -248,18 +257,13 @@ bool mei_cl_bus_notify_event(struct mei_cl *cl)
 {
 	struct mei_cl_device *cldev = cl->cldev;
 
-	if (!cldev || !cldev->event_cb)
-		return false;
-
-	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)))
+	if (!cldev || !cldev->notif_cb)
 		return false;
 
 	if (!cl->notify_ev)
 		return false;
 
-	set_bit(MEI_CL_EVENT_NOTIF, &cldev->events);
-
-	schedule_work(&cldev->event_work);
+	schedule_work(&cldev->notif_work);
 
 	cl->notify_ev = false;
 
@@ -267,7 +271,7 @@ bool mei_cl_bus_notify_event(struct mei_cl *cl)
 }
 
 /**
- * mei_cl_bus_rx_event  - schedule rx event
+ * mei_cl_bus_rx_event - schedule rx event
  *
  * @cl: host client
  *
@@ -278,64 +282,81 @@ bool mei_cl_bus_rx_event(struct mei_cl *cl)
 {
 	struct mei_cl_device *cldev = cl->cldev;
 
-	if (!cldev || !cldev->event_cb)
-		return false;
-
-	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_RX)))
+	if (!cldev || !cldev->rx_cb)
 		return false;
 
-	set_bit(MEI_CL_EVENT_RX, &cldev->events);
-
-	schedule_work(&cldev->event_work);
+	schedule_work(&cldev->rx_work);
 
 	return true;
 }
 
 /**
- * mei_cldev_register_event_cb - register event callback
+ * mei_cldev_register_rx_cb - register Rx event callback
  *
  * @cldev: me client devices
- * @event_cb: callback function
- * @events_mask: requested events bitmask
+ * @rx_cb: callback function
  *
  * Return: 0 on success
  *         -EALREADY if an callback is already registered
  *         <0 on other errors
  */
-int mei_cldev_register_event_cb(struct mei_cl_device *cldev,
-				unsigned long events_mask,
-				mei_cldev_event_cb_t event_cb)
+int mei_cldev_register_rx_cb(struct mei_cl_device *cldev, mei_cldev_cb_t rx_cb)
 {
 	struct mei_device *bus = cldev->bus;
 	int ret;
 
-	if (cldev->event_cb)
+	if (!rx_cb)
+		return -EINVAL;
+	if (cldev->rx_cb)
 		return -EALREADY;
 
-	cldev->events = 0;
-	cldev->events_mask = events_mask;
-	cldev->event_cb = event_cb;
-	INIT_WORK(&cldev->event_work, mei_cl_bus_event_work);
+	cldev->rx_cb = rx_cb;
+	INIT_WORK(&cldev->rx_work, mei_cl_bus_rx_work);
 
-	if (cldev->events_mask & BIT(MEI_CL_EVENT_RX)) {
-		mutex_lock(&bus->device_lock);
-		ret = mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
-		mutex_unlock(&bus->device_lock);
-		if (ret && ret != -EBUSY)
-			return ret;
-	}
+	mutex_lock(&bus->device_lock);
+	ret = mei_cl_read_start(cldev->cl, mei_cl_mtu(cldev->cl), NULL);
+	mutex_unlock(&bus->device_lock);
+	if (ret && ret != -EBUSY)
+		return ret;
 
-	if (cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)) {
-		mutex_lock(&bus->device_lock);
-		ret = mei_cl_notify_request(cldev->cl, NULL, event_cb ? 1 : 0);
-		mutex_unlock(&bus->device_lock);
-		if (ret)
-			return ret;
-	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(mei_cldev_register_rx_cb);
+
+/**
+ * mei_cldev_register_notif_cb - register FW notification event callback
+ *
+ * @cldev: me client devices
+ * @notif_cb: callback function
+ *
+ * Return: 0 on success
+ *         -EALREADY if an callback is already registered
+ *         <0 on other errors
+ */
+int mei_cldev_register_notif_cb(struct mei_cl_device *cldev,
+				mei_cldev_cb_t notif_cb)
+{
+	struct mei_device *bus = cldev->bus;
+	int ret;
+
+	if (!notif_cb)
+		return -EINVAL;
+
+	if (cldev->notif_cb)
+		return -EALREADY;
+
+	cldev->notif_cb = notif_cb;
+	INIT_WORK(&cldev->notif_work, mei_cl_bus_notif_work);
+
+	mutex_lock(&bus->device_lock);
+	ret = mei_cl_notify_request(cldev->cl, NULL, 1);
+	mutex_unlock(&bus->device_lock);
+	if (ret)
+		return ret;
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(mei_cldev_register_event_cb);
+EXPORT_SYMBOL_GPL(mei_cldev_register_notif_cb);
 
 /**
  * mei_cldev_get_drvdata - driver data getter
@@ -471,8 +492,6 @@ int mei_cldev_disable(struct mei_cl_device *cldev)
 
 	bus = cldev->bus;
 
-	cldev->event_cb = NULL;
-
 	mutex_lock(&bus->device_lock);
 
 	if (!mei_cl_is_connected(cl)) {
@@ -619,9 +638,13 @@ static int mei_cl_device_remove(struct device *dev)
 	if (!cldev || !dev->driver)
 		return 0;
 
-	if (cldev->event_cb) {
-		cldev->event_cb = NULL;
-		cancel_work_sync(&cldev->event_work);
+	if (cldev->rx_cb) {
+		cancel_work_sync(&cldev->rx_work);
+		cldev->rx_cb = NULL;
+	}
+	if (cldev->notif_cb) {
+		cancel_work_sync(&cldev->notif_work);
+		cldev->notif_cb = NULL;
 	}
 
 	cldrv = to_mei_cl_driver(dev->driver);
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 46ee9155ada6..9635b14b6011 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -673,6 +673,11 @@ int mei_cl_unlink(struct mei_cl *cl)
 	list_del_init(&cl->link);
 
 	cl->state = MEI_FILE_UNINITIALIZED;
+	cl->writing_state = MEI_IDLE;
+
+	WARN_ON(!list_empty(&cl->rd_completed) ||
+		!list_empty(&cl->rd_pending) ||
+		!list_empty(&cl->link));
 
 	return 0;
 }
diff --git a/drivers/nfc/mei_phy.c b/drivers/nfc/mei_phy.c
index 03139c5a05e4..8a04c5e02999 100644
--- a/drivers/nfc/mei_phy.c
+++ b/drivers/nfc/mei_phy.c
@@ -297,9 +297,11 @@ static int mei_nfc_recv(struct nfc_mei_phy *phy, u8 *buf, size_t length)
 }
 
 
-static void nfc_mei_event_cb(struct mei_cl_device *cldev, u32 events)
+static void nfc_mei_rx_cb(struct mei_cl_device *cldev)
 {
 	struct nfc_mei_phy *phy = mei_cldev_get_drvdata(cldev);
+	struct sk_buff *skb;
+	int reply_size;
 
 	if (!phy)
 		return;
@@ -307,27 +309,22 @@ static void nfc_mei_event_cb(struct mei_cl_device *cldev, u32 events)
 	if (phy->hard_fault != 0)
 		return;
 
-	if (events & BIT(MEI_CL_EVENT_RX)) {
-		struct sk_buff *skb;
-		int reply_size;
-
-		skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
-		if (!skb)
-			return;
+	skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
+	if (!skb)
+		return;
 
-		reply_size = mei_nfc_recv(phy, skb->data, MEI_NFC_MAX_READ);
-		if (reply_size < MEI_NFC_HEADER_SIZE) {
-			kfree_skb(skb);
-			return;
-		}
+	reply_size = mei_nfc_recv(phy, skb->data, MEI_NFC_MAX_READ);
+	if (reply_size < MEI_NFC_HEADER_SIZE) {
+		kfree_skb(skb);
+		return;
+	}
 
-		skb_put(skb, reply_size);
-		skb_pull(skb, MEI_NFC_HEADER_SIZE);
+	skb_put(skb, reply_size);
+	skb_pull(skb, MEI_NFC_HEADER_SIZE);
 
-		MEI_DUMP_SKB_IN("mei frame read", skb);
+	MEI_DUMP_SKB_IN("mei frame read", skb);
 
-		nfc_hci_recv_frame(phy->hdev, skb);
-	}
+	nfc_hci_recv_frame(phy->hdev, skb);
 }
 
 static int nfc_mei_phy_enable(void *phy_id)
@@ -358,8 +355,7 @@ static int nfc_mei_phy_enable(void *phy_id)
 		goto err;
 	}
 
-	r = mei_cldev_register_event_cb(phy->cldev, BIT(MEI_CL_EVENT_RX),
-					nfc_mei_event_cb);
+	r = mei_cldev_register_rx_cb(phy->cldev, nfc_mei_rx_cb);
 	if (r) {
 		pr_err("Event cb registration failed %d\n", r);
 		goto err;
diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index 40953fe4db86..b29c6fde7473 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -412,11 +412,11 @@ static void mei_wdt_unregister_work(struct work_struct *work)
 }
 
 /**
- * mei_wdt_event_rx - callback for data receive
+ * mei_wdt_rx - callback for data receive
  *
  * @cldev: bus device
  */
-static void mei_wdt_event_rx(struct mei_cl_device *cldev)
+static void mei_wdt_rx(struct mei_cl_device *cldev)
 {
 	struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
 	struct mei_wdt_start_response res;
@@ -484,11 +484,11 @@ static void mei_wdt_event_rx(struct mei_cl_device *cldev)
 }
 
 /*
- * mei_wdt_notify_event - callback for event notification
+ * mei_wdt_notif - callback for event notification
  *
  * @cldev: bus device
  */
-static void mei_wdt_notify_event(struct mei_cl_device *cldev)
+static void mei_wdt_notif(struct mei_cl_device *cldev)
 {
 	struct mei_wdt *wdt = mei_cldev_get_drvdata(cldev);
 
@@ -498,21 +498,6 @@ static void mei_wdt_notify_event(struct mei_cl_device *cldev)
 	mei_wdt_register(wdt);
 }
 
-/**
- * mei_wdt_event - callback for event receive
- *
- * @cldev: bus device
- * @events: event mask
- */
-static void mei_wdt_event(struct mei_cl_device *cldev, u32 events)
-{
-	if (events & BIT(MEI_CL_EVENT_RX))
-		mei_wdt_event_rx(cldev);
-
-	if (events & BIT(MEI_CL_EVENT_NOTIF))
-		mei_wdt_notify_event(cldev);
-}
-
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 
 static ssize_t mei_dbgfs_read_activation(struct file *file, char __user *ubuf,
@@ -623,16 +608,17 @@ static int mei_wdt_probe(struct mei_cl_device *cldev,
 		goto err_out;
 	}
 
-	ret = mei_cldev_register_event_cb(wdt->cldev,
-					  BIT(MEI_CL_EVENT_RX) |
-					  BIT(MEI_CL_EVENT_NOTIF),
-					  mei_wdt_event);
+	ret = mei_cldev_register_rx_cb(wdt->cldev, mei_wdt_rx);
+	if (ret) {
+		dev_err(&cldev->dev, "Could not reg rx event ret=%d\n", ret);
+		goto err_disable;
+	}
 
+	ret = mei_cldev_register_notif_cb(wdt->cldev, mei_wdt_notif);
 	/* on legacy devices notification is not supported
-	 * this doesn't fail the registration for RX event
 	 */
 	if (ret && ret != -EOPNOTSUPP) {
-		dev_err(&cldev->dev, "Could not register event ret=%d\n", ret);
+		dev_err(&cldev->dev, "Could not reg notif event ret=%d\n", ret);
 		goto err_disable;
 	}
 
diff --git a/include/linux/mei_cl_bus.h b/include/linux/mei_cl_bus.h
index 4adb2e7c9f84..017f5232b3de 100644
--- a/include/linux/mei_cl_bus.h
+++ b/include/linux/mei_cl_bus.h
@@ -8,8 +8,7 @@
 struct mei_cl_device;
 struct mei_device;
 
-typedef void (*mei_cldev_event_cb_t)(struct mei_cl_device *cldev,
-				     u32 events);
+typedef void (*mei_cldev_cb_t)(struct mei_cl_device *cldev);
 
 /**
  * struct mei_cl_device - MEI device handle
@@ -24,11 +23,12 @@ typedef void (*mei_cldev_event_cb_t)(struct mei_cl_device *cldev,
  * @me_cl: me client
  * @cl: mei client
  * @name: device name
- * @event_work: async work to execute event callback
- * @event_cb: Drivers register this callback to get asynchronous ME
- *	events (e.g. Rx buffer pending) notifications.
- * @events_mask: Events bit mask requested by driver.
- * @events: Events bitmask sent to the driver.
+ * @rx_work: async work to execute Rx event callback
+ * @rx_cb: Drivers register this callback to get asynchronous ME
+ *	Rx buffer pending notifications.
+ * @notif_work: async work to execute FW notif event callback
+ * @notif_cb: Drivers register this callback to get asynchronous ME
+ *	FW notification pending notifications.
  *
  * @do_match: wheather device can be matched with a driver
  * @is_added: device is already scanned
@@ -43,10 +43,10 @@ struct mei_cl_device {
 	struct mei_cl *cl;
 	char name[MEI_CL_NAME_SIZE];
 
-	struct work_struct event_work;
-	mei_cldev_event_cb_t event_cb;
-	unsigned long events_mask;
-	unsigned long events;
+	struct work_struct rx_work;
+	mei_cldev_cb_t rx_cb;
+	struct work_struct notif_work;
+	mei_cldev_cb_t notif_cb;
 
 	unsigned int do_match:1;
 	unsigned int is_added:1;
@@ -88,13 +88,9 @@ void mei_cldev_driver_unregister(struct mei_cl_driver *cldrv);
 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);
 
-int mei_cldev_register_event_cb(struct mei_cl_device *cldev,
-				unsigned long event_mask,
-				mei_cldev_event_cb_t read_cb);
-
-#define MEI_CL_EVENT_RX 0
-#define MEI_CL_EVENT_TX 1
-#define MEI_CL_EVENT_NOTIF 2
+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,
+				mei_cldev_cb_t notif_cb);
 
 const uuid_le *mei_cldev_uuid(const struct mei_cl_device *cldev);
 u8 mei_cldev_ver(const struct mei_cl_device *cldev);
-- 
2.7.4

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