[char-misc-next 4/4] mei: bus: enable non-blocking RX

[Tomas Winkler <tomas.winkler@intel.com>]

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

Enable non-blocking receive for drivers on mei bus, this allows checking
for data availability by mei client drivers. This is most effective for
fixed address clients, that lacks flow control.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
---
 drivers/misc/mei/bus-fixup.c |  4 ++--
 drivers/misc/mei/bus.c       | 19 ++++++++++++++++---
 drivers/misc/mei/mei_dev.h   |  7 ++++++-
 drivers/nfc/mei_phy.c        |  7 ++++---
 drivers/watchdog/mei_wdt.c   |  2 +-
 include/linux/mei_cl_bus.h   |  3 ++-
 6 files changed, 31 insertions(+), 11 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..45e937937675 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -98,15 +98,18 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
  * @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)) {
@@ -197,14 +205,19 @@ EXPORT_SYMBOL_GPL(mei_cldev_send);
  * @cldev: me client device
  * @buf: buffer to receive
  * @length: buffer length
+ * @flags: read io flags [O_NONBLOCK]
  *
  * Return: read size in bytes of < 0 on error
  */
-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,
+		       unsigned int flags)
 {
 	struct mei_cl *cl = cldev->cl;
+	unsigned int mode;
+
+	mode = (flags & O_NONBLOCK) ? MEI_CL_IO_RX_NONBLOCK : 0;
 
-	return __mei_cl_recv(cl, buf, length);
+	return __mei_cl_recv(cl, buf, length, mode);
 }
 EXPORT_SYMBOL_GPL(mei_cldev_recv);
 
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 82e69a00b7a1..f16bd1209848 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),
 };
 
 /*
@@ -318,7 +322,8 @@ 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/drivers/nfc/mei_phy.c b/drivers/nfc/mei_phy.c
index 8a04c5e02999..0e8158c5f81b 100644
--- a/drivers/nfc/mei_phy.c
+++ b/drivers/nfc/mei_phy.c
@@ -132,7 +132,8 @@ static int mei_nfc_if_version(struct nfc_mei_phy *phy)
 	if (!reply)
 		return -ENOMEM;
 
-	bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply, if_version_length);
+	bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply,
+				    if_version_length, 0);
 	if (bytes_recv < 0 || bytes_recv < if_version_length) {
 		pr_err("Could not read IF version\n");
 		r = -EIO;
@@ -193,7 +194,7 @@ static int mei_nfc_connect(struct nfc_mei_phy *phy)
 	}
 
 	bytes_recv = mei_cldev_recv(phy->cldev, (u8 *)reply,
-				    connect_resp_length);
+				    connect_resp_length, 0);
 	if (bytes_recv < 0) {
 		r = bytes_recv;
 		pr_err("Could not read connect response %d\n", r);
@@ -279,7 +280,7 @@ static int mei_nfc_recv(struct nfc_mei_phy *phy, u8 *buf, size_t length)
 	struct mei_nfc_hdr *hdr;
 	int received_length;
 
-	received_length = mei_cldev_recv(phy->cldev, buf, length);
+	received_length = mei_cldev_recv(phy->cldev, buf, length, 0);
 	if (received_length < 0)
 		return received_length;
 
diff --git a/drivers/watchdog/mei_wdt.c b/drivers/watchdog/mei_wdt.c
index b29c6fde7473..3e29af534f8e 100644
--- a/drivers/watchdog/mei_wdt.c
+++ b/drivers/watchdog/mei_wdt.c
@@ -423,7 +423,7 @@ static void mei_wdt_rx(struct mei_cl_device *cldev)
 	const size_t res_len = sizeof(res);
 	int ret;
 
-	ret = mei_cldev_recv(wdt->cldev, (u8 *)&res, res_len);
+	ret = mei_cldev_recv(wdt->cldev, (u8 *)&res, res_len, 0);
 	if (ret < 0) {
 		dev_err(&cldev->dev, "failure in recv %d\n", ret);
 		return;
diff --git a/include/linux/mei_cl_bus.h b/include/linux/mei_cl_bus.h
index 017f5232b3de..c3bb565f0745 100644
--- a/include/linux/mei_cl_bus.h
+++ b/include/linux/mei_cl_bus.h
@@ -86,7 +86,8 @@ 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,
+		       unsigned int flags);
 
 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,
-- 
2.7.4