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Message-ID: <AANLkTincey6stwEhyK1ZRwcp5eUzC73GQv6Q_We=+gcX@mail.gmail.com>
Date: Thu, 9 Dec 2010 15:05:25 +0900
From: Kyungmin Park <kmpark@...radead.org>
To: "Dong, Chuanxiao" <chuanxiao.dong@...el.com>
Cc: "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"cjb@...top.org" <cjb@...top.org>,
"arjan@...ux.intel.com" <arjan@...ux.intel.com>,
"alan@...ux.intel.com" <alan@...ux.intel.com>,
"akpm@...ux-foundation.org" <akpm@...ux-foundation.org>
Subject: Re: [PATCH v4 1/4]enable HW reset capbility
On Thu, Dec 9, 2010 at 2:40 PM, Dong, Chuanxiao
<chuanxiao.dong@...el.com> wrote:
>
>
>> -----Original Message-----
>> From: kyungmin78@...il.com [mailto:kyungmin78@...il.com] On Behalf Of
>> Kyungmin Park
>> Sent: Thursday, December 09, 2010 1:24 PM
>> To: Dong, Chuanxiao
>> Cc: linux-mmc@...r.kernel.org; linux-kernel@...r.kernel.org; cjb@...top.org;
>> arjan@...ux.intel.com; alan@...ux.intel.com; akpm@...ux-foundation.org
>> Subject: Re: [PATCH v4 1/4]enable HW reset capbility
>>
>> On Wed, Dec 1, 2010 at 9:49 PM, Chuanxiao Dong <chuanxiao.dong@...el.com>
>> wrote:
>> > From d3be0b4fe8e8a40294830dfd8d0543d1e957fd29 Mon Sep 17 00:00:00 2001
>> > From: Chuanxiao Dong <chuanxiao.dong@...el.com>
>> > 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@...el.com>
>> > ---
>> > 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
>
> Thanks, Park. I will fix this.
> And by the way, I noticed mmc_read_ext_csd function also used card->ext_csd.rev >=4. Is there some other reason for this kind of using? Or it is just because at that time the value 4 has not be obsolete yet....?
Maybe need to fix it also.
And remaining patches also need to fix 'capability' typo.
Thank you,
Kyungmin Park
>
> Thanks.
> Chuanxiao
>> > + 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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>> >
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