mmc: Read eMMC partition access bits before card reset
eMMC specification in section "Access partitions" says that all reset
events will restore the access bits in PARTITION_CONFIG CSD register to
default User Data Area value (0b000).
So read partition access bits from PARTITION_CONFIG CSD register before
issuing card reset. This allows SPL/U-Boot to get information which eMMC
partition was in use before SPL/U-Boot was booted. For some platforms this
is the way how to determinate boot partition from which BootROM loaded SPL.
Signed-off-by: Pali Rohár <pali@kernel.org>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 1af6af8..9915610 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -2329,8 +2329,17 @@
/* store the partition info of emmc */
mmc->part_support = ext_csd[EXT_CSD_PARTITIONING_SUPPORT];
if ((ext_csd[EXT_CSD_PARTITIONING_SUPPORT] & PART_SUPPORT) ||
- ext_csd[EXT_CSD_BOOT_MULT])
- mmc->part_config = ext_csd[EXT_CSD_PART_CONF];
+ ext_csd[EXT_CSD_BOOT_MULT]) {
+ /*
+ * At this stage PART_ACCESS_MASK bits in ext_csd[] are already cleared.
+ * But it is possible that they were already filled into mmc->part_config.
+ */
+ if (mmc->part_config == MMCPART_NOAVAILABLE)
+ mmc->part_config = ext_csd[EXT_CSD_PART_CONF];
+ else
+ mmc->part_config = (ext_csd[EXT_CSD_PART_CONF] & ~PART_ACCESS_MASK) |
+ (mmc->part_config & PART_ACCESS_MASK);
+ }
if (part_completed &&
(ext_csd[EXT_CSD_PARTITIONING_SUPPORT] & ENHNCD_SUPPORT))
mmc->part_attr = ext_csd[EXT_CSD_PARTITIONS_ATTRIBUTE];
@@ -2603,7 +2612,6 @@
#if CONFIG_IS_ENABLED(MMC_WRITE)
mmc->erase_grp_size = 1;
#endif
- mmc->part_config = MMCPART_NOAVAILABLE;
err = mmc_startup_v4(mmc);
if (err)
@@ -2851,9 +2859,26 @@
return err;
mmc->ddr_mode = 0;
+ mmc->part_config = MMCPART_NOAVAILABLE;
+
retry:
mmc_set_initial_state(mmc);
+ /*
+ * Read partition access bits from partition config register before card reset command
+ * because these bits are reset to default value (User Data Area) during card reset.
+ * This allows us to preserve original value of partition access bits used by the code
+ * which loaded us (for example BootROM) and use it for board specific boot purposes.
+ */
+ if (mmc->part_config == MMCPART_NOAVAILABLE) {
+ ALLOC_CACHE_ALIGN_BUFFER(u8, ext_csd, MMC_MAX_BLOCK_LEN);
+ err = mmc_send_ext_csd(mmc, ext_csd);
+ if (err == 0 &&
+ ((ext_csd[EXT_CSD_PARTITIONING_SUPPORT] & PART_SUPPORT) ||
+ ext_csd[EXT_CSD_BOOT_MULT]))
+ mmc->part_config = ext_csd[EXT_CSD_PART_CONF] & PART_ACCESS_MASK;
+ }
+
/* Reset the Card */
err = mmc_go_idle(mmc);