[OSS-Tools] [PATCH v2 4/8] libdt: factor out __of_cdev_find helper

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

of_get_devicepath is an exported symbol by libdt, so we shouldn't change
its signature or its semantics. Yet, we will want to export more
information out of the udev'ification code in future. <dt/dt.h> already
declares an opaque struct cdev, so let's add a __of_cdev_find helper
that can populate it with the same information that of_get_devicepath
would return. In later commits we will define helpers that return
and process a struct cdev placed in dynamic memory.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 src/libdt.c | 82 +++++++++++++++++++++++++++++++++--------------------
 1 file changed, 52 insertions(+), 30 deletions(-)

diff --git a/src/libdt.c b/src/libdt.c
index a4f0e256ef6a..c8a8ea43e452 100644
--- a/src/libdt.c
+++ b/src/libdt.c
@@ -32,6 +32,12 @@
 #include <libudev.h>
 #include <dt.h>
 
+struct cdev {
+	char *devpath;
+	off_t offset;
+	size_t size;
+};
+
 static int pr_level = 5;
 
 void pr_level_set(int level)
@@ -2482,33 +2488,14 @@ static struct udev_device *of_find_device_by_uuid(struct udev_device *parent,
 	return NULL;
 }
 
-/*
- * of_get_devicepath - get information how to access device corresponding to a device_node
- * @partition_node:	The device_node which shall be accessed
- * @devpath:		Returns the devicepath under which the device is accessible
- * @offset:		Returns the offset in the device
- * @size:		Returns the size of the device
- *
- * This function takes a device_node which represents a partition.
- * For this partition the function returns the device path and the offset
- * and size in the device. For mtd devices the path will be /dev/mtdx, for
- * EEPROMs it will be /sys/.../eeprom and for block devices it will be /dev/...
- * For mtd devices the device path returned will be the partition itself.
- * Since EEPROMs do not have partitions under Linux @offset and @size will
- * describe the offset and size inside the full device. The same applies to
- * block devices.
- *
- * returns 0 for success or negative error value on failure.
- */
-int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t *offset,
-		size_t *size)
+static int __of_cdev_find(struct device_node *partition_node, struct cdev *cdev)
 {
 	struct device_node *node;
 	struct udev_device *dev, *partdev, *mtd;
 	int ret;
 
-	*offset = 0;
-	*size = 0;
+	cdev->offset = 0;
+	cdev->size = 0;
 
 	/*
 	 * simplest case: This nodepath can directly be translated into
@@ -2520,8 +2507,8 @@ int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t
 	dev = of_find_device_by_node_path(partition_node->full_name);
 	if (dev) {
 		if (udev_device_is_eeprom(dev))
-			return udev_parse_eeprom(dev, devpath);
-		if (!udev_parse_mtd(dev, devpath, size))
+			return udev_parse_eeprom(dev, &cdev->devpath);
+		if (!udev_parse_mtd(dev, &cdev->devpath, &cdev->size))
 			return 0;
 
 		/*
@@ -2553,7 +2540,7 @@ int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t
 			while (*uuid)
 				*s++ = tolower(*uuid++);
 
-			*devpath = lc_uuid;
+			cdev->devpath = lc_uuid;
 
 			return 0;
 		}
@@ -2609,21 +2596,56 @@ int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t
 			return -ENODEV;
 
 		/* ...find the desired information by mtd udev_device */
-		return udev_parse_mtd(partdev, devpath, size);
+		return udev_parse_mtd(partdev, &cdev->devpath, &cdev->size);
 	}
 
 	if (udev_device_is_eeprom(dev)) {
-		ret = udev_parse_eeprom(dev, devpath);
+		ret = udev_parse_eeprom(dev, &cdev->devpath);
 		if (ret)
 			return ret;
 
-		return of_parse_partition(partition_node, offset, size);
+		return of_parse_partition(partition_node, &cdev->offset, &cdev->size);
 	} else {
-		ret = device_find_block_device(dev, devpath);
+		ret = device_find_block_device(dev, &cdev->devpath);
 		if (ret)
 			return ret;
-		return of_parse_partition(partition_node, offset, size);
+		return of_parse_partition(partition_node, &cdev->offset, &cdev->size);
 	}
 
 	return -EINVAL;
 }
+
+/*
+ * of_get_devicepath - get information how to access device corresponding to a device_node
+ * @partition_node:	The device_node which shall be accessed
+ * @devpath:		Returns the devicepath under which the device is accessible
+ * @offset:		Returns the offset in the device
+ * @size:		Returns the size of the device
+ *
+ * This function takes a device_node which represents a partition.
+ * For this partition the function returns the device path and the offset
+ * and size in the device. For mtd devices the path will be /dev/mtdx, for
+ * EEPROMs it will be /sys/.../eeprom and for block devices it will be /dev/...
+ * For mtd devices the device path returned will be the partition itself.
+ * Since EEPROMs do not have partitions under Linux @offset and @size will
+ * describe the offset and size inside the full device. The same applies to
+ * block devices.
+ *
+ * returns 0 for success or negative error value on failure.
+ */
+int of_get_devicepath(struct device_node *partition_node, char **devpath, off_t *offset,
+		size_t *size)
+{
+	struct cdev cdev = {};
+	int ret;
+
+	ret = __of_cdev_find(partition_node, &cdev);
+	if (ret)
+		return ret;
+
+	*offset = cdev.offset;
+	*size = cdev.size;
+	*devpath = cdev.devpath;
+
+	return 0;
+}
-- 
2.39.2