platform/chrome: cros_ec: Separate logic for getting panic info

Create a separate function called cros_ec_get_panicinfo for getting
panic info from EC.

Currently cros_ec_create_panicinfo is the only caller.

Signed-off-by: Rob Barnes <robbarnes@google.com>
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20230410165817.932449-1-robbarnes@google.com

Author: rbbrns

drivers/platform/chrome/cros_ec_debugfs.c

@@ -400,24 +400,48 @@ static void cros_ec_cleanup_console_log(struct cros_ec_debugfs *debug_info)
 	}
 }
 
-static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
+/**
+ * Returns the size of the panicinfo data fetched from the EC
+ */
+static int cros_ec_get_panicinfo(struct cros_ec_device *ec_dev, uint8_t *data,
+				 int data_size)
 {
-	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
 	int ret;
 	struct cros_ec_command *msg;
-	int insize;
 
-	insize = ec_dev->max_response;
+	if (!data || data_size <= 0 || data_size > ec_dev->max_response)
+		return -EINVAL;
 
-	msg = devm_kzalloc(debug_info->ec->dev,
-			sizeof(*msg) + insize, GFP_KERNEL);
+	msg = kzalloc(sizeof(*msg) + data_size, GFP_KERNEL);
 	if (!msg)
 		return -ENOMEM;
 
 	msg->command = EC_CMD_GET_PANIC_INFO;
-	msg->insize = insize;
+	msg->insize = data_size;
 
 	ret = cros_ec_cmd_xfer_status(ec_dev, msg);
+	if (ret < 0)
+		goto free;
+
+	memcpy(data, msg->data, data_size);
+
+free:
+	kfree(msg);
+	return ret;
+}
+
+static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
+{
+	struct cros_ec_device *ec_dev = debug_info->ec->ec_dev;
+	int ret;
+	void *data;
+
+	data = devm_kzalloc(debug_info->ec->dev, ec_dev->max_response,
+			    GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	ret = cros_ec_get_panicinfo(ec_dev, data, ec_dev->max_response);
 	if (ret < 0) {
 		ret = 0;
 		goto free;
@@ -427,7 +451,7 @@ static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
 	if (ret == 0)
 		goto free;
 
-	debug_info->panicinfo_blob.data = msg->data;
+	debug_info->panicinfo_blob.data = data;
 	debug_info->panicinfo_blob.size = ret;
 
 	debugfs_create_blob("panicinfo", S_IFREG | 0444, debug_info->dir,
@@ -436,7 +460,7 @@ static int cros_ec_create_panicinfo(struct cros_ec_debugfs *debug_info)
 	return 0;
 
 free:
-	devm_kfree(debug_info->ec->dev, msg);
+	devm_kfree(debug_info->ec->dev, data);
 	return ret;
 }