Hi, Alex.
On 11/27/2014 10:59 PM, Alex Lemberg wrote:
> Hi Jaehoon,
>
>> -----Original Message-----
>> From: Jaehoon Chung [mailto:jh80.ch...@samsung.com]
>> Sent: Thursday, November 27, 2014 11:02 AM
>> To: Alex Lemberg
>> Cc: ulf.hans...@linaro.org; linux-mmc@vger.kernel.org; ch...@printf.net; 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:jh80.ch...@samsung.com]
>>>> Sent: Wednesday, November 26, 2014 6:33 AM
>>>> To: Alex Lemberg; ulf.hans...@linaro.org
>>>> Cc: linux-mmc@vger.kernel.org; ch...@printf.net; 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 <alex.lemb...@sandisk.com>
>>>>> ---
>>>>> 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?
Sorry, i missed that checking EXT_CSD_PSA_POST_SOLDERING_WIRTES.
Then you need to relocated this at correct place.(To get ext_csd value), right?
Best Regards,
Jaehoon Chung
>
>>
>>>
>>>
>>>>> + 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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