dm: disk: add UCLASS_PARTITION

NOTE: probably we have to update config dependencies,
in particular, SPL/TPL_PRINTF?

With this new function, UCLASS_PARTITION devices will be created as
child nodes of UCLASS_BLK device.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

include/dm/uclass-id.h

@@ -83,6 +83,7 @@ enum uclass_id {
 	UCLASS_P2SB,		/* (x86) Primary-to-Sideband Bus */
 	UCLASS_PANEL,		/* Display panel, such as an LCD */
 	UCLASS_PANEL_BACKLIGHT,	/* Backlight controller for panel */
+	UCLASS_PARTITION,	/* Logical disk partition device */
 	UCLASS_PCH,		/* x86 platform controller hub */
 	UCLASS_PCI,		/* PCI bus */
 	UCLASS_PCI_EP,		/* PCI endpoint device */

include/part.h

@@ -303,6 +303,16 @@ part_get_info_by_dev_and_name_or_num(const char *dev_iface,
 }
 #endif
 
+struct udevice;
+/**
+ * part_create_block_devices - Create block devices for disk partitions
+ *
+ * Create UCLASS_PARTITION udevices for each of disk partitions in @parent
+ *
+ * @blk_dev:	Whole disk device
+ */
+int part_create_block_devices(struct udevice *blk_dev);
+
 /*
  * We don't support printing partition information in SPL and only support
  * getting partition information in a few cases.