Hi Jaehoon,
> -----Original Message-----
> From: Jaehoon Chung [mailto:[email protected]]
> Sent: Thursday, November 27, 2014 11:02 AM
> To: Alex Lemberg
> Cc: [email protected]; [email protected]; [email protected]; Avi
> Shchislowski
> Subject: Re: [PATCH v2] mmc: Add Production State Awareness Support
>
> Hi, Alex.
>
> On 11/27/2014 01:38 AM, Alex Lemberg wrote:
> > Hi Jaehoon,
> >
> > Thank you for reviewing the patch.
> >
> >> -----Original Message-----
> >> From: Jaehoon Chung [mailto:[email protected]]
> >> Sent: Wednesday, November 26, 2014 6:33 AM
> >> To: Alex Lemberg; [email protected]
> >> Cc: [email protected]; [email protected]; Avi Shchislowski
> >> Subject: Re: [PATCH v2] mmc: Add Production State Awareness Support
> >>
> >> Hi,
> >>
> >> On 11/26/2014 12:01 AM, Alex Lemberg wrote:
> >>> In this patch driver should recognize if eMMC device (Rev >=5.0) was
> >>> left in PRE_SOLDERING_POST_WRITES (0x02) state, and switch it to
> >>> NORMAL (0x00).
> >>> PRE_SOLDERING_POST_WRITES (0x02) state - represents a state where
> >>> the device is in production process and the host (usually
> >>> programmer) completed loading the content to the device.
> >>> The host (usually programmer) sets the device to this state after
> >>> loading the content and just before soldering.
> >>> After soldering the device to the real host (not programmer), the
> >>> device should be switched to NORMAL (0x00) mode.
> >>> The NORMAL (0x00) mode of PSA register represents a state in which
> >>> the device is running in the field and uses regular operations.
> >>> Leaving device in PRE_SOLDERING_POST_WRITES (0x02) might cause
> >>> unexpected behaviour of eMMC device.
> >>>
> >>> More details about PSA feature can be found in eMMC5.0 JEDEC spec
> >> (JESD84-B50.pdf):
> >>> http://www.jedec.org/standards-documents/technology-focus-areas/flas
> >>> h-
> >>> memory-ssds-ufs-emmc/e-mmc
> >>>
> >>> Signed-off-by: Alex Lemberg <[email protected]>
> >>> ---
> >>> Changes in v2:
> >>> - Remove typo in patch code
> >>> ---
> >>> drivers/mmc/core/mmc.c | 28 ++++++++++++++++++++++++++++
> >>> include/linux/mmc/card.h | 2 ++
> >>> include/linux/mmc/mmc.h | 8 ++++++++
> >>> 3 files changed, 38 insertions(+)
> >>>
> >>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
> >>> 02ad792..3923c90 100644
> >>> --- a/drivers/mmc/core/mmc.c
> >>> +++ b/drivers/mmc/core/mmc.c
> >>> @@ -571,6 +571,16 @@ 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);
> >>> + card->ext_csd.psa =
> >>> + ext_csd[EXT_CSD_PSA];
> >>> + if (ext_csd[EXT_CSD_PSA_TIMEOUT] > 0) {
> >>> + card->ext_csd.psa_timeout =
> >>> + 100 *
> >>> + (1 << ext_csd[EXT_CSD_PSA_TIMEOUT]);
> >>> + } else {
> >>> + pr_warn("%s: EXT_CSD PSA Timeout is zero\n",
> >>> + mmc_hostname(card->host));
> >>
> >> I remembered Ulf's previous comment. Did you check it?
> > Are you referring to psa_timeout?
> > In case it is zero, we are printing warning, and let host controller
> > to handle this.
> > Every switch command timeout setting in mmc driver done in this way.
>
> pr_warn() doesn't need.
OK
>
> >>
> >>> + }
> >>> }
> >>> out:
> >>> return err;
> >>> @@ -1331,6 +1341,24 @@ static int mmc_init_card(struct mmc_host
> >>> *host,
> >> u32 ocr,
> >>> mmc_set_dsr(host);
> >>>
> >>> /*
> >>> + * eMMC v5.0 or later
> >>> + * and Production State Awareness state is
> >>> + * EXT_CSD_PSA_POST_SOLDERING_WRITES (0x02)
> >>> + * The host should set the device to NORMAL mode
> >>> + */
> >>> + if ((card->ext_csd.rev >= 7) &&
> >>> + (card->ext_csd.psa ==
> >> EXT_CSD_PSA_POST_SOLDERING_WRITES)) {
> >>
> >> Is it right? how did you get "revision"?
> >
> > In linux-next, the EXT_CSD revision set was moved to
> > mmc_decode_ext_csd() function.
> > Anyway, thanks for pointing me on this, I will move this check to the
> > right place.
> >
> >>
> >>> + unsigned int timeout;
> >>> +
> >>> + timeout = DIV_ROUND_UP(card->ext_csd.psa_timeout, 1000);
> >>> + card->ext_csd.psa = EXT_CSD_PSA_NORMAL;
> >>
> >> Why did card->ext_csd.psa assign to EXT_CSD_PSA_NORMAL as hard-
> coding?
> >>
> > I think this is a right way to set ext_csd structure in order to
> > prevent additional read from device ext_csd register, which was already read
> during the init.
>
> I think you assume that card is already initialized.
>
> In my understanding for your code.
> a) init time
> card->ext_csd.psa assigned to EXT_CSD_PSA_NORMAL. (hard coding)
> And switch to EXT_CSD_PSA_NORMAL.
> b) If oldcard doesn't present, try to read ext_csd register.
> Then EXT_CSD_PSA was always set to EXT_CSD_PSA_NORMAL. isn't?
> And card->ext_csd.psa is re-assigned to EXT_CSD_PSA register value.
> (It's also EXT_CSD_PSA_NORMAL, because it's switched to
> EXT_CSD_PSA_NORMA at 'a)' )
>
> If i missed something, let me know.
'b)' is performed before 'a)'
The card->ext_csd.psa is read from device before we check and set it to NORMAL.
The code flow is:
mmc_init_card(...)
{
...
1) If oldcard doesn't present, try to read ext_csd register.
The card->ext_csd.psa will be set with device register value
...
2) if card->ext_csd.psa is EXT_CSD_PSA_POST_SOLDERING_WRITES
Set card->ext_csd.psa to EXT_CSD_PSA_NORMAL. (hard coding)
And switch to EXT_CSD_PSA_NORMAL
...
}
Does it makes more sense now?
>
> >
> >
> >>> + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> >>> + EXT_CSD_PSA, card->ext_csd.psa, timeout);
>
> If you need to change,
> err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_PSA,
> EXT_CSD_PSA_NORMAL, timeout);
>
> Anyway, this sequence is something strange.
>
> Best Regards,
> Jaehoon Chung
> >>> + if (err && err != -EBADMSG)
> >>> + goto free_card;
> >>> + }
> >>> +
> >>> + /*
> >>> * Select card, as all following commands rely on that.
> >>> */
> >>> if (!mmc_host_is_spi(host)) {
> >>> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> >>> index
> >>> 4d69c00..09ac3b0 100644
> >>> --- a/include/linux/mmc/card.h
> >>> +++ b/include/linux/mmc/card.h
> >>> @@ -60,9 +60,11 @@ struct mmc_ext_csd {
> >>> u8 packed_event_en;
> >>> unsigned int part_time; /* Units: ms */
> >>> unsigned int sa_timeout; /* Units: 100ns */
> >>> + unsigned int psa_timeout; /* Units: 100us */
> >>> unsigned int generic_cmd6_time; /* Units: 10ms */
> >>> unsigned int power_off_longtime; /* Units: ms */
> >>> u8 power_off_notification; /* state */
> >>> + u8 psa; /* production state awareness */
> >>> unsigned int hs_max_dtr;
> >>> unsigned int hs200_max_dtr;
> >>> #define MMC_HIGH_26_MAX_DTR 26000000
> >>> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h index
> >>> 49ad7a9..458814d 100644
> >>> --- a/include/linux/mmc/mmc.h
> >>> +++ b/include/linux/mmc/mmc.h
> >>> @@ -285,6 +285,7 @@ struct _mmc_csd {
> >>> #define EXT_CSD_EXP_EVENTS_STATUS 54 /* RO, 2 bytes */
> >>> #define EXT_CSD_EXP_EVENTS_CTRL 56 /* R/W, 2
> bytes */
> >>> #define EXT_CSD_DATA_SECTOR_SIZE 61 /* R */
> >>> +#define EXT_CSD_PSA 133 /* R/W/E */
> >>> #define EXT_CSD_GP_SIZE_MULT 143 /* R/W */
> >>> #define EXT_CSD_PARTITION_SETTING_COMPLETED 155 /* R/W */
> >>> #define EXT_CSD_PARTITION_ATTRIBUTE 156 /* R/W */
> >>> @@ -315,6 +316,7 @@ struct _mmc_csd {
> >>> #define EXT_CSD_PWR_CL_26_360 203 /* RO */
> >>> #define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
> >>> #define EXT_CSD_S_A_TIMEOUT 217 /* RO */
> >>> +#define EXT_CSD_PSA_TIMEOUT 218 /* RO */
> >>> #define EXT_CSD_REL_WR_SEC_C 222 /* RO */
> >>> #define EXT_CSD_HC_WP_GRP_SIZE 221 /* RO */
> >>> #define EXT_CSD_ERASE_TIMEOUT_MULT 223 /* RO */
> >>> @@ -433,6 +435,12 @@ struct _mmc_csd {
> >>> #define EXT_CSD_BKOPS_LEVEL_2 0x2
> >>>
> >>> /*
> >>> + * PRODUCTION STATE AWARENESS fields */
> >>> +#define EXT_CSD_PSA_NORMAL 0x00
> >>> +#define EXT_CSD_PSA_POST_SOLDERING_WRITES 0x02
> >>> +
> >>> +/*
> >>> * MMC_SWITCH access modes
> >>> */
> >>>
> >>>
> >
> >
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