On Wed, Dec 1, 2010 at 9:49 PM, Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx> wrote:
> 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
Check hardware.
> + */
> + 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.
capability.
> + * Enable this feature here:
> + * RST_N_FUNCTION register is W/R, one time programmable
Use RST_n_FUNCTION as spec.
> + * 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 &&
it should be card->ext_csd.rev >= 5 since 4 is obsolete.
Thank you,
Kyungmin Park
> + 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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