Enhance Strobe is defined in v5.1 eMMC spec. This commit
is to implement it.
Signed-off-by: Yi Sun <yi.y.sun@xxxxxxxxx>
---
drivers/mmc/core/mmc.c | 61 ++++++++++++++++++++++++++++++++++++++++++----
include/linux/mmc/card.h | 1 +
include/linux/mmc/mmc.h | 2 ++
3 files changed, 59 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index e519e31..c9ef2de 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -585,6 +585,12 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
card->ext_csd.ffu_capable =
(ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
!(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
+
+ /* Enhance Strobe is supported since v5.1 which rev should be
+ * 8 but some eMMC devices can support it with rev 7. So handle
+ * Enhance Strobe here.
+ */
+ card->ext_csd.strobe_support = ext_csd[EXT_CSD_STROBE_SUPPORT];
}
out:
return err;
@@ -1049,9 +1055,28 @@ static int mmc_select_hs400(struct mmc_card *card)
/*
* HS400 mode requires 8-bit bus width
*/
- if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
- host->ios.bus_width == MMC_BUS_WIDTH_8))
- return 0;
+ if (card->ext_csd.strobe_support) {
+ if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ host->caps & MMC_CAP_8_BIT_DATA))
+ return 0;
+
+ /* For Enhance Strobe flow. For non Enhance Strobe, signal
+ * voltage will not be set.
+ */
+ if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_2V)
+ err = __mmc_set_signal_voltage(host,
+ MMC_SIGNAL_VOLTAGE_120);
+
+ if (err && card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200_1_8V)
+ err = __mmc_set_signal_voltage(host,
+ MMC_SIGNAL_VOLTAGE_180);
+ if (err)
+ return err;
+ } else {
+ if (!(card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ host->ios.bus_width == MMC_BUS_WIDTH_8))
+ return 0;
+ }
/*
* Before switching to dual data rate operation for HS400,
@@ -1072,15 +1097,36 @@ static int mmc_select_hs400(struct mmc_card *card)
return err;
}
+ val = EXT_CSD_DDR_BUS_WIDTH_8;
+ if (card->ext_csd.strobe_support)
+ val |= EXT_CSD_BUS_WIDTH_STROBE;
err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
EXT_CSD_BUS_WIDTH,
- EXT_CSD_DDR_BUS_WIDTH_8,
+ val,
card->ext_csd.generic_cmd6_time);
if (err) {
pr_err("%s: switch to bus width for hs400 failed, err:%d\n",
mmc_hostname(host), err);
return err;
}
+ if (card->ext_csd.strobe_support) {
+ mmc_set_bus_width(host, MMC_BUS_WIDTH_8);
+ /*
+ * If controller can't handle bus width test,
+ * compare ext_csd previously read in 1 bit mode
+ * against ext_csd at new bus width
+ */
+ if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
+ err = mmc_compare_ext_csds(card, MMC_BUS_WIDTH_8);
+ else
+ err = mmc_bus_test(card, MMC_BUS_WIDTH_8);
+
+ if (err) {
+ pr_warn("%s: switch to bus width %d failed\n",
+ mmc_hostname(host), MMC_BUS_WIDTH_8);
+ return err;
+ }
+ }
val = EXT_CSD_TIMING_HS400 |
card->drive_strength << EXT_CSD_DRV_STR_SHIFT;
@@ -1263,7 +1309,12 @@ static int mmc_select_timing(struct mmc_card *card)
if (!mmc_can_ext_csd(card))
goto bus_speed;
- if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
+ /* For Enhance Strobe HS400 flow */
+ if (card->ext_csd.strobe_support &&
+ card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS400 &&
+ card->host->caps & MMC_CAP_8_BIT_DATA)
+ err = mmc_select_hs400(card);
+ else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS200)
err = mmc_select_hs200(card);
else if (card->mmc_avail_type & EXT_CSD_CARD_TYPE_HS)
err = mmc_select_hs(card);
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 4d3776d..b793b61 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -95,6 +95,7 @@ struct mmc_ext_csd {
u8 raw_partition_support; /* 160 */
u8 raw_rpmb_size_mult; /* 168 */
u8 raw_erased_mem_count; /* 181 */
+ u8 strobe_support; /* 184 */
u8 raw_ext_csd_structure; /* 194 */
u8 raw_card_type; /* 196 */
u8 raw_driver_strength; /* 197 */
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 15f2c4a..a1bb32c 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -297,6 +297,7 @@ struct _mmc_csd {
#define EXT_CSD_PART_CONFIG 179 /* R/W */
#define EXT_CSD_ERASED_MEM_CONT 181 /* RO */
#define EXT_CSD_BUS_WIDTH 183 /* R/W */
+#define EXT_CSD_STROBE_SUPPORT 184 /* RO */
#define EXT_CSD_HS_TIMING 185 /* R/W */
#define EXT_CSD_POWER_CLASS 187 /* R/W */
#define EXT_CSD_REV 192 /* RO */
@@ -386,6 +387,7 @@ struct _mmc_csd {
#define EXT_CSD_BUS_WIDTH_8 2 /* Card is in 8 bit mode */
#define EXT_CSD_DDR_BUS_WIDTH_4 5 /* Card is in 4 bit DDR mode */
#define EXT_CSD_DDR_BUS_WIDTH_8 6 /* Card is in 8 bit DDR mode */
+#define EXT_CSD_BUS_WIDTH_STROBE 0x80 /* Card is in 8 bit DDR mode */
#define EXT_CSD_TIMING_BC 0 /* Backwards compatility */
#define EXT_CSD_TIMING_HS 1 /* High speed */
--
1.7.9.5
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