mei: add timeout to send

When driver wakes up the firmware from the low power state,
it is sending a memory ready message.
The send is done via synchronous/blocking function to ensure
that firmware is in ready state. However, in case of firmware
undergoing reset send might be block forever.
To address this issue a timeout is added to blocking
write command on the internal bus.

Introduce the __mei_cl_send_timeout function to use instead of
__mei_cl_send in cases where timeout is required.
The mei_cl_write has only two callers and there is no need to split
it into two functions.

Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Link: https://lore.kernel.org/r/20221116124735.2493847-2-alexander.usyskin@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/bus-fixup.c

@@ -188,17 +188,20 @@ static int mei_fwver(struct mei_cl_device *cldev)
 	return ret;
 }
 
+#define GFX_MEMORY_READY_TIMEOUT 200 /* timeout in milliseconds */
+
 static int mei_gfx_memory_ready(struct mei_cl_device *cldev)
 {
 	struct mkhi_gfx_mem_ready req = {0};
-	unsigned int mode = MEI_CL_IO_TX_INTERNAL;
+	unsigned int mode = MEI_CL_IO_TX_INTERNAL | MEI_CL_IO_TX_BLOCKING;
 
 	req.hdr.group_id = MKHI_GROUP_ID_GFX;
 	req.hdr.command = MKHI_GFX_MEMORY_READY_CMD_REQ;
 	req.flags = MKHI_GFX_MEM_READY_PXP_ALLOWED;
 
 	dev_dbg(&cldev->dev, "Sending memory ready command\n");
-	return __mei_cl_send(cldev->cl, (u8 *)&req, sizeof(req), 0, mode);
+	return __mei_cl_send_timeout(cldev->cl, (u8 *)&req, sizeof(req), 0,
+				     mode, GFX_MEMORY_READY_TIMEOUT);
 }
 
 static void mei_mkhi_fix(struct mei_cl_device *cldev)

drivers/misc/mei/bus.c

@@ -33,6 +33,26 @@
  */
 ssize_t __mei_cl_send(struct mei_cl *cl, const u8 *buf, size_t length, u8 vtag,
 		      unsigned int mode)
+{
+	return __mei_cl_send_timeout(cl, buf, length, vtag, mode, MAX_SCHEDULE_TIMEOUT);
+}
+
+/**
+ * __mei_cl_send_timeout - internal client send (write)
+ *
+ * @cl: host client
+ * @buf: buffer to send
+ * @length: buffer length
+ * @vtag: virtual tag
+ * @mode: sending mode
+ * @timeout: send timeout in milliseconds.
+ *           effective only for blocking writes: the MEI_CL_IO_TX_BLOCKING mode bit is set.
+ *           set timeout to the MAX_SCHEDULE_TIMEOUT to maixum allowed wait.
+ *
+ * Return: written size bytes or < 0 on error
+ */
+ssize_t __mei_cl_send_timeout(struct mei_cl *cl, const u8 *buf, size_t length, u8 vtag,
+			      unsigned int mode, unsigned long timeout)
 {
 	struct mei_device *bus;
 	struct mei_cl_cb *cb;
@@ -101,7 +121,7 @@ ssize_t __mei_cl_send(struct mei_cl *cl, const u8 *buf, size_t length, u8 vtag,
 	cb->blocking = !!(mode & MEI_CL_IO_TX_BLOCKING);
 	memcpy(cb->buf.data, buf, length);
 
-	rets = mei_cl_write(cl, cb);
+	rets = mei_cl_write(cl, cb, timeout);
 
 out:
 	mutex_unlock(&bus->device_lock);

drivers/misc/mei/client.c

@@ -1926,10 +1926,13 @@ int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
  *
  * @cl: host client
  * @cb: write callback with filled data
+ * @timeout: send timeout in milliseconds.
+ *           effective only for blocking writes: the cb->blocking is set.
+ *           set timeout to the MAX_SCHEDULE_TIMEOUT to maixum allowed wait.
  *
  * Return: number of bytes sent on success, <0 on failure.
  */
-ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
+ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, unsigned long timeout)
 {
 	struct mei_device *dev;
 	struct mei_msg_data *buf;
@@ -2056,11 +2059,20 @@ ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb)
 	if (blocking && cl->writing_state != MEI_WRITE_COMPLETE) {
 
 		mutex_unlock(&dev->device_lock);
-		rets = wait_event_interruptible(cl->tx_wait,
-				cl->writing_state == MEI_WRITE_COMPLETE ||
-				(!mei_cl_is_connected(cl)));
+		rets = wait_event_interruptible_timeout(cl->tx_wait,
+							cl->writing_state == MEI_WRITE_COMPLETE ||
+							(!mei_cl_is_connected(cl)),
+							msecs_to_jiffies(timeout));
 		mutex_lock(&dev->device_lock);
+		/* clean all queue on timeout as something fatal happened */
+		if (rets == 0) {
+			rets = -ETIME;
+			mei_io_tx_list_free_cl(&dev->write_list, cl, NULL);
+			mei_io_tx_list_free_cl(&dev->write_waiting_list, cl, NULL);
+		}
 		/* wait_event_interruptible returns -ERESTARTSYS */
+		if (rets > 0)
+			rets = 0;
 		if (rets) {
 			if (signal_pending(current))
 				rets = -EINTR;

drivers/misc/mei/client.h

@@ -246,7 +246,7 @@ int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
 int mei_cl_irq_connect(struct mei_cl *cl, struct mei_cl_cb *cb,
 		       struct list_head *cmpl_list);
 int mei_cl_read_start(struct mei_cl *cl, size_t length, const struct file *fp);
-ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb);
+ssize_t mei_cl_write(struct mei_cl *cl, struct mei_cl_cb *cb, unsigned long timeout);
 int mei_cl_irq_write(struct mei_cl *cl, struct mei_cl_cb *cb,
 		     struct list_head *cmpl_list);
 

drivers/misc/mei/main.c

@@ -383,7 +383,7 @@ static ssize_t mei_write(struct file *file, const char __user *ubuf,
 		goto out;
 	}
 
-	rets = mei_cl_write(cl, cb);
+	rets = mei_cl_write(cl, cb, MAX_SCHEDULE_TIMEOUT);
 out:
 	mutex_unlock(&dev->device_lock);
 	return rets;

drivers/misc/mei/mei_dev.h

@@ -373,6 +373,8 @@ 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, const u8 *buf, size_t length, u8 vtag,
 		      unsigned int mode);
+ssize_t __mei_cl_send_timeout(struct mei_cl *cl, const u8 *buf, size_t length, u8 vtag,
+			      unsigned int mode, unsigned long timeout);
 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length, u8 *vtag,
 		      unsigned int mode, unsigned long timeout);
 bool mei_cl_bus_rx_event(struct mei_cl *cl);