platform/chrome: cros_ec_proto: Use EC struct for features

The Chrome EC's features are returned through an
ec_response_get_features struct, but they are stored in an independent
array. Although the two are effectively the same at present (2 unsigned
32 bit ints), there is the possibility that they could go out of sync.
Avoid this by only using the EC struct to store the features.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Link: https://lore.kernel.org/r/20211004170716.86601-1-pmalani@chromium.org
Signed-off-by: Benson Leung <bleung@chromium.org>

Author: Prashant Malani

drivers/mfd/cros_ec_dev.c

@@ -146,8 +146,8 @@ static int ec_device_probe(struct platform_device *pdev)
 	ec->ec_dev = dev_get_drvdata(dev->parent);
 	ec->dev = dev;
 	ec->cmd_offset = ec_platform->cmd_offset;
-	ec->features[0] = -1U; /* Not cached yet */
-	ec->features[1] = -1U; /* Not cached yet */
+	ec->features.flags[0] = -1U; /* Not cached yet */
+	ec->features.flags[1] = -1U; /* Not cached yet */
 	device_initialize(&ec->class_dev);
 
 	for (i = 0; i < ARRAY_SIZE(cros_mcu_devices); i++) {

drivers/platform/chrome/cros_ec_proto.c

@@ -812,36 +812,37 @@ EXPORT_SYMBOL(cros_ec_get_host_event);
  */
 bool cros_ec_check_features(struct cros_ec_dev *ec, int feature)
 {
+	struct ec_response_get_features *features = &ec->features;
 	struct cros_ec_command *msg;
 	int ret;
 
-	if (ec->features[0] == -1U && ec->features[1] == -1U) {
+	if (features->flags[0] == -1U && features->flags[1] == -1U) {
 		/* features bitmap not read yet */
-		msg = kzalloc(sizeof(*msg) + sizeof(ec->features), GFP_KERNEL);
+		msg = kzalloc(sizeof(*msg) + sizeof(*features), GFP_KERNEL);
 		if (!msg) {
 			dev_err(ec->dev, "failed to allocate memory to get EC features\n");
 			return false;
 		}
 
 		msg->command = EC_CMD_GET_FEATURES + ec->cmd_offset;
-		msg->insize = sizeof(ec->features);
+		msg->insize = sizeof(*features);
 
 		ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 		if (ret < 0) {
 			dev_warn(ec->dev, "cannot get EC features: %d/%d\n",
 				 ret, msg->result);
-			memset(ec->features, 0, sizeof(ec->features));
+			memset(features, 0, sizeof(*features));
 		} else {
-			memcpy(ec->features, msg->data, sizeof(ec->features));
+			memcpy(features, msg->data, sizeof(*features));
 		}
 
 		dev_dbg(ec->dev, "EC features %08x %08x\n",
-			ec->features[0], ec->features[1]);
+			features->flags[0], features->flags[1]);
 
 		kfree(msg);
 	}
 
-	return !!(ec->features[feature / 32] & EC_FEATURE_MASK_0(feature));
+	return !!(features->flags[feature / 32] & EC_FEATURE_MASK_0(feature));
 }
 EXPORT_SYMBOL_GPL(cros_ec_check_features);
 

include/linux/platform_data/cros_ec_proto.h

@@ -205,7 +205,7 @@ struct cros_ec_dev {
 	struct cros_ec_debugfs *debug_info;
 	bool has_kb_wake_angle;
 	u16 cmd_offset;
-	u32 features[2];
+	struct ec_response_get_features features;
 };
 
 #define to_cros_ec_dev(dev)  container_of(dev, struct cros_ec_dev, class_dev)