The block interface is not well documented in the code. Pick two important functions and add comments.
Signed-off-by: Simon Glass sjg@chromium.org Reviewed-by: Bin Meng bmeng.cn@gmail.com ---
Changes in v2: None
include/part.h | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+)
diff --git a/include/part.h b/include/part.h index 2599998..4e70d8d 100644 --- a/include/part.h +++ b/include/part.h @@ -53,12 +53,42 @@ typedef struct disk_partition {
/* Misc _get_dev functions */ #ifdef CONFIG_PARTITIONS +/** + * get_dev() - get a pointer to a block device given its type and 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, so the interface name must be provided. + * + * @ifname: Interface name (e.g. "ide", "scsi") + * @dev: Device number (0 for first device on that interface, 1 for + * second, etc. + * @return pointer to the block device, or NULL if not available, or an + * error occurred. + */ struct blk_desc *get_dev(const char *ifname, int dev); struct blk_desc *ide_get_dev(int dev); struct blk_desc *sata_get_dev(int dev); struct blk_desc *scsi_get_dev(int dev); struct blk_desc *usb_stor_get_dev(int dev); struct blk_desc *mmc_get_dev(int dev); + +/** + * mmc_select_hwpart() - Select the MMC hardware partiion on an MMC device + * + * MMC devices 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). + * + * @dev_num: Block device number (struct blk_desc->dev value) + * @hwpart: Hardware partition number to select. 0 means the raw device, + * 1 is the first partition, 2 is the second, etc. + * @return 0 if OK, other value for an error + */ int mmc_select_hwpart(int dev_num, int hwpart); struct blk_desc *systemace_get_dev(int dev); struct blk_desc *mg_disk_get_dev(int dev);