platform/chrome: cros_ec_proto: separate cros_ec_wait_until_complete()

EC returns EC_RES_IN_PROGRESS if the host command needs more time to
complete.  Whenever receives the return code, cros_ec_send_command()
sends EC_CMD_GET_COMMS_STATUS to query the command status.

Separate cros_ec_wait_until_complete() from cros_ec_send_command().
It sends EC_CMD_GET_COMMS_STATUS and waits until the previous command
was completed, or encountered error, or timed out.
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Link: https://lore.kernel.org/r/20220718050914.2267370-7-tzungbi@kernel.org

drivers/platform/chrome/cros_ec_proto.c

@@ -134,52 +134,48 @@ static int cros_ec_xfer_command(struct cros_ec_device *ec_dev, struct cros_ec_co
 	return ret;
 }
 
-static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
+static int cros_ec_wait_until_complete(struct cros_ec_device *ec_dev, uint32_t *result)
 {
-	int ret = cros_ec_xfer_command(ec_dev, msg);
-
-	if (msg->result == EC_RES_IN_PROGRESS) {
-		int i;
-		struct cros_ec_command *status_msg;
-		struct ec_response_get_comms_status *status;
-
-		status_msg = kmalloc(sizeof(*status_msg) + sizeof(*status),
-				     GFP_KERNEL);
-		if (!status_msg)
-			return -ENOMEM;
+	struct {
+		struct cros_ec_command msg;
+		struct ec_response_get_comms_status status;
+	} __packed buf;
+	struct cros_ec_command *msg = &buf.msg;
+	struct ec_response_get_comms_status *status = &buf.status;
+	int ret = 0, i;
 
-		status_msg->version = 0;
-		status_msg->command = EC_CMD_GET_COMMS_STATUS;
-		status_msg->insize = sizeof(*status);
-		status_msg->outsize = 0;
+	msg->version = 0;
+	msg->command = EC_CMD_GET_COMMS_STATUS;
+	msg->insize = sizeof(*status);
+	msg->outsize = 0;
 
-		/*
-		 * Query the EC's status until it's no longer busy or
-		 * we encounter an error.
-		 */
-		for (i = 0; i < EC_COMMAND_RETRIES; i++) {
+	/* Query the EC's status until it's no longer busy or we encounter an error. */
+	for (i = 0; i < EC_COMMAND_RETRIES; ++i) {
 		usleep_range(10000, 11000);
 
-			trace_cros_ec_request_start(status_msg);
-			ret = (*xfer_fxn)(ec_dev, status_msg);
-			trace_cros_ec_request_done(status_msg, ret);
+		ret = cros_ec_xfer_command(ec_dev, msg);
 		if (ret == -EAGAIN)
 			continue;
 		if (ret < 0)
-				break;
+			return ret;
 
-			msg->result = status_msg->result;
-			if (status_msg->result != EC_RES_SUCCESS)
-				break;
+		*result = msg->result;
+		if (msg->result != EC_RES_SUCCESS)
+			return ret;
 
-			status = (struct ec_response_get_comms_status *)
-				 status_msg->data;
 		if (!(status->flags & EC_COMMS_STATUS_PROCESSING))
-				break;
+			return ret;
 	}
 
-		kfree(status_msg);
-	}
+	return ret;
+}
+
+static int cros_ec_send_command(struct cros_ec_device *ec_dev, struct cros_ec_command *msg)
+{
+	int ret = cros_ec_xfer_command(ec_dev, msg);
+
+	if (msg->result == EC_RES_IN_PROGRESS)
+		ret = cros_ec_wait_until_complete(ec_dev, &msg->result);
 
 	return ret;
 }