mmc: core: Expose access to RPMB partition

Following JEDEC standard, if the mmc supports RPMB partition,
a new interface is created and exposed via /dev/block.
Users will be able to access RPMB partition using standard
mmc IOCTL commands.

Signed-off-by: Alex Macro <alex.macro@stericsson.com>
Signed-off-by: Loic Pallardy <loic.pallardy@stericsson.com>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Johan Rudholm <johan.rudholm@stericsson.com>
Acked-by: Krishna Konda <kkonda@codeaurora.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

drivers/mmc/core/mmc.c

@@ -491,6 +491,17 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
 
 		card->ext_csd.rel_param = ext_csd[EXT_CSD_WR_REL_PARAM];
 		card->ext_csd.rst_n_function = ext_csd[EXT_CSD_RST_N_FUNCTION];
+
+		/*
+		 * RPMB regions are defined in multiples of 128K.
+		 */
+		card->ext_csd.raw_rpmb_size_mult = ext_csd[EXT_CSD_RPMB_MULT];
+		if (ext_csd[EXT_CSD_RPMB_MULT]) {
+			mmc_part_add(card, ext_csd[EXT_CSD_RPMB_MULT] << 17,
+				EXT_CSD_PART_CONFIG_ACC_RPMB,
+				"rpmb", 0, false,
+				MMC_BLK_DATA_AREA_RPMB);
+		}
 	}
 
 	card->ext_csd.raw_erased_mem_count = ext_csd[EXT_CSD_ERASED_MEM_CONT];

include/linux/mmc/card.h

@@ -85,6 +85,7 @@ struct mmc_ext_csd {
 	bool			boot_ro_lockable;
 	u8			raw_exception_status;	/* 53 */
 	u8			raw_partition_support;	/* 160 */
+	u8			raw_rpmb_size_mult;	/* 168 */
 	u8			raw_erased_mem_count;	/* 181 */
 	u8			raw_ext_csd_structure;	/* 194 */
 	u8			raw_card_type;		/* 196 */
@@ -206,6 +207,7 @@ struct mmc_part {
 #define MMC_BLK_DATA_AREA_MAIN	(1<<0)
 #define MMC_BLK_DATA_AREA_BOOT	(1<<1)
 #define MMC_BLK_DATA_AREA_GP	(1<<2)
+#define MMC_BLK_DATA_AREA_RPMB	(1<<3)
 };
 
 /*

include/linux/mmc/mmc.h

@@ -286,6 +286,7 @@ struct _mmc_csd {
 #define EXT_CSD_BKOPS_START		164	/* W */
 #define EXT_CSD_SANITIZE_START		165     /* W */
 #define EXT_CSD_WR_REL_PARAM		166	/* RO */
+#define EXT_CSD_RPMB_MULT		168	/* RO */
 #define EXT_CSD_BOOT_WP			173	/* R/W */
 #define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */
 #define EXT_CSD_PART_CONFIG		179	/* R/W */
@@ -339,6 +340,7 @@ struct _mmc_csd {
 
 #define EXT_CSD_PART_CONFIG_ACC_MASK	(0x7)
 #define EXT_CSD_PART_CONFIG_ACC_BOOT0	(0x1)
+#define EXT_CSD_PART_CONFIG_ACC_RPMB	(0x3)
 #define EXT_CSD_PART_CONFIG_ACC_GP0	(0x4)
 
 #define EXT_CSD_PART_SUPPORT_PART_EN	(0x1)