dm: blk: Add a legacy block interface

There is quite a bit of duplicated common code related to block devices
in the IDE and SCSI implementations.

Create some helper functions that can be used to reduce the duplication.
These rely on a linker list of interface-type drivers

Signed-off-by: Simon Glass <sjg@chromium.org>

include/blk.h

@@ -340,6 +340,201 @@ static inline ulong blk_derase(struct blk_desc *block_dev, lbaint_t start,
 	blkcache_invalidate(block_dev->if_type, block_dev->devnum);
 	return block_dev->block_erase(block_dev, start, blkcnt);
 }
+
+/**
+ * struct blk_driver - Driver for block interface types
+ *
+ * This provides access to the block devices for each interface type. One
+ * driver should be provided using U_BOOT_LEGACY_BLK() for each interface
+ * type that is to be supported.
+ *
+ * @if_typename:	Interface type name
+ * @if_type:		Interface type
+ * @max_devs:		Maximum number of devices supported
+ * @desc:		Pointer to list of devices for this interface type,
+ *			or NULL to use @get_dev() instead
+ */
+struct blk_driver {
+	const char *if_typename;
+	enum if_type if_type;
+	int max_devs;
+	struct blk_desc *desc;
+	/**
+	 * get_dev() - get a pointer to a block device given its number
+	 *
+	 * Each interface allocates its own devices and typically
+	 * struct blk_desc is contained with the interface's data structure.
+	 * There is no global numbering for block devices. This method allows
+	 * the device for an interface type to be obtained when @desc is NULL.
+	 *
+	 * @devnum:	Device number (0 for first device on that interface,
+	 *		1 for second, etc.
+	 * @descp:	Returns pointer to the block device on success
+	 * @return 0 if OK, -ve on error
+	 */
+	int (*get_dev)(int devnum, struct blk_desc **descp);
+
+	/**
+	 * select_hwpart() - Select a hardware partition
+	 *
+	 * Some devices (e.g. MMC) can support partitioning at the hardware
+	 * level. This is quite separate from the normal idea of
+	 * software-based partitions. MMC hardware partitions must be
+	 * explicitly selected. Once selected only the region of the device
+	 * covered by that partition is accessible.
+	 *
+	 * The MMC standard provides for two boot partitions (numbered 1 and 2),
+	 * rpmb (3), and up to 4 addition general-purpose partitions (4-7).
+	 * Partition 0 is the main user-data partition.
+	 *
+	 * @desc:	Block device descriptor
+	 * @hwpart:	Hardware partition number to select. 0 means the main
+	 *		user-data partition, 1 is the first partition, 2 is
+	 *		the second, etc.
+	 * @return 0 if OK, other value for an error
+	 */
+	int (*select_hwpart)(struct blk_desc *desc, int hwpart);
+};
+
+/*
+ * Declare a new U-Boot legacy block driver. New drivers should use driver
+ * model (UCLASS_BLK).
+ */
+#define U_BOOT_LEGACY_BLK(__name)					\
+	ll_entry_declare(struct blk_driver, __name, blk_driver)
+
+struct blk_driver *blk_driver_lookup_type(int if_type);
+
 #endif /* !CONFIG_BLK */
 
+/**
+ * blk_get_devnum_by_typename() - Get a block device by type and number
+ *
+ * This looks through the available block devices of the given type, returning
+ * the one with the given @devnum.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return point to block device descriptor, or NULL if not found
+ */
+struct blk_desc *blk_get_devnum_by_type(enum if_type if_type, int devnum);
+
+/**
+ * blk_get_devnum_by_type() - Get a block device by type name, and number
+ *
+ * This looks up the block device type based on @if_typename, then calls
+ * blk_get_devnum_by_type().
+ *
+ * @if_typename:	Block device type name
+ * @devnum:		Device number
+ * @return point to block device descriptor, or NULL if not found
+ */
+struct blk_desc *blk_get_devnum_by_typename(const char *if_typename,
+					    int devnum);
+
+/**
+ * blk_dselect_hwpart() - select a hardware partition
+ *
+ * This selects a hardware partition (such as is supported by MMC). The block
+ * device size may change as this effectively points the block device to a
+ * partition at the hardware level. See the select_hwpart() method above.
+ *
+ * @desc:	Block device descriptor for the device to select
+ * @hwpart:	Partition number to select
+ * @return 0 if OK, -ve on error
+ */
+int blk_dselect_hwpart(struct blk_desc *desc, int hwpart);
+
+/**
+ * blk_list_part() - list the partitions for block devices of a given type
+ *
+ * This looks up the partition type for each block device of type @if_type,
+ * then displays a list of partitions.
+ *
+ * @if_type:	Block device type
+ * @return 0 if OK, -ENODEV if there is none of that type
+ */
+int blk_list_part(enum if_type if_type);
+
+/**
+ * blk_list_devices() - list the block devices of a given type
+ *
+ * This lists each block device of the type @if_type, showing the capacity
+ * as well as type-specific information.
+ *
+ * @if_type:	Block device type
+ */
+void blk_list_devices(enum if_type if_type);
+
+/**
+ * blk_show_device() - show information about a given block device
+ *
+ * This shows the block device capacity as well as type-specific information.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENODEV for invalid device number
+ */
+int blk_show_device(enum if_type if_type, int devnum);
+
+/**
+ * blk_print_device_num() - show information about a given block device
+ *
+ * This is similar to blk_show_device() but returns an error if the block
+ * device type is unknown.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENODEV for invalid device number, -ENOENT if the block
+ * device is not connected
+ */
+int blk_print_device_num(enum if_type if_type, int devnum);
+
+/**
+ * blk_print_part_devnum() - print the partition information for a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @return 0 if OK, -ENOENT if the block device is not connected, -ENOSYS if
+ * the interface type is not supported, other -ve on other error
+ */
+int blk_print_part_devnum(enum if_type if_type, int devnum);
+
+/**
+ * blk_read_devnum() - read blocks from a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @blkcnt:	Number of blocks to read
+ * @buffer:	Address to write data to
+ * @return number of blocks read, or -ve error number on error
+ */
+ulong blk_read_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		      lbaint_t blkcnt, void *buffer);
+
+/**
+ * blk_write_devnum() - write blocks to a device
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @blkcnt:	Number of blocks to write
+ * @buffer:	Address to read data from
+ * @return number of blocks written, or -ve error number on error
+ */
+ulong blk_write_devnum(enum if_type if_type, int devnum, lbaint_t start,
+		       lbaint_t blkcnt, const void *buffer);
+
+/**
+ * blk_select_hwpart_devnum() - select a hardware partition
+ *
+ * This is similar to blk_dselect_hwpart() but it looks up the interface and
+ * device number.
+ *
+ * @if_type:	Block device type
+ * @devnum:	Device number
+ * @hwpart:	Partition number to select
+ * @return 0 if OK, -ve on error
+ */
+int blk_select_hwpart_devnum(enum if_type if_type, int devnum, int hwpart);
+
 #endif