>From d3be0b4fe8e8a40294830dfd8d0543d1e957fd29 Mon Sep 17 00:00:00 2001
From: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
Date: Wed, 1 Dec 2010 19:14:02 +0800
Subject: [PATCH 1/4] enable HW reset caps of MMC card if card supports
HW reset capbility 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 occures
timeout errors during read/write/erase.
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
---
drivers/mmc/core/mmc.c | 29 +++++++++++++++++++++++++++++
include/linux/mmc/card.h | 1 +
include/linux/mmc/mmc.h | 1 +
3 files changed, 31 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 77f93c3..85cc7f6 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -310,6 +310,10 @@ 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 cap
+ */
+ card->ext_csd.rst = ext_csd[EXT_CSD_RST];
}
if (ext_csd[EXT_CSD_ERASED_MEM_CONT])
@@ -484,6 +488,31 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
}
/*
+ * eMMC4.4 version card has HW reset capbility.
+ * 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 >= 4 &&
+ 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) {
+ printk(KERN_WARNING "%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 956fbd8..b7ab0da 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -251,6 +251,7 @@ 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
--
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