HW reset capability enable bit is byte 162 in card EXT_CSD register, only
version4.4 card or later can support to enable this feature.
HW reset feature can be used to reset eMMC card when occurs timeout error
during read/write/erase even eMMC card cannot correspond any command
Signed-off-by: Chuanxiao Dong <[email protected]>
---
drivers/mmc/core/mmc.c | 24 ++++++++++++++++++++++++
include/linux/mmc/card.h | 1 +
include/linux/mmc/mmc.h | 1 +
3 files changed, 26 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 1d8409f..ebb5748 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -310,6 +310,8 @@ static int mmc_read_ext_csd(struct mmc_card *card)
ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT];
card->ext_csd.trim_timeout = 300 *
ext_csd[EXT_CSD_TRIM_MULT];
+ /* check Hardware reset capability */
+ card->ext_csd.rst = ext_csd[EXT_CSD_RST];
}
if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
@@ -484,6 +486,28 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
}
/*
+ * eMMC4.4 version card has HW reset capability. Enable this feature
+ * here. RST_N_FUNCTION register is W/R, one time programmable or
+ * readable. So need to enable this register only once after power on
+ */
+ if (card->csd.mmca_vsn >= CSD_SPEC_VER_4 &&
+ card->ext_csd.rev >= 5 &&
+ card->ext_csd.rst == 0) {
+ err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+ EXT_CSD_RST, 1);
+
+ if (err && err != -EBADMSG)
+ goto free_card;
+
+ if (err) {
+ pr_warn("%s: switch to rst enable failed %d\n",
+ mmc_hostname(card->host), err);
+ err = 0;
+ } else
+ card->ext_csd.rst = 1;
+ }
+
+ /*
* Activate high speed (if supported)
*/
if ((card->ext_csd.hs_max_dtr != 0) &&
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 8ce0827..ebee676 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -54,6 +54,7 @@ struct mmc_ext_csd {
unsigned int sec_trim_mult; /* Secure trim multiplier */
unsigned int sec_erase_mult; /* Secure erase multiplier */
unsigned int trim_timeout; /* In milliseconds */
+ unsigned int rst; /* hardware reset enable bit */
};
struct sd_scr {
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 612301f..ed86b78 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -253,6 +253,7 @@ struct _mmc_csd {
* EXT_CSD fields
*/
+#define EXT_CSD_RST 162 /* onetime programmable R/W */
#define EXT_CSD_ERASE_GROUP_DEF 175 /* R/W */
#define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
#define EXT_CSD_BUS_WIDTH 183 /* R/W */
--
1.6.6.1