[U-Boot] [RFC PATCH 1/1] Read mmc device memory capacity from EXT_CSD if memory is addressed by sector

[Jaehoon Chung]

Hi Tomas,

On 11/23/2016 10:04 PM, Tomas Melin wrote:
> Hi,
> 
> We have successfully been using this patch to fix the problem mentioned in the
> original message. Could this be picked up upstream?

Sorry. I didn't see this patch..Could you again send the patch without RFC?
Then it's helpful to me for checking this.

Best Regards,
Jaehoon Chung

> 
> BR,
> Tomas
> 
> On Wed Feb 5 21:00:42 CET 2014, Frank Bormann wrote:
>> Hello Everyone,
>>
>> I believe, there is a bug in the mmc driver code pertaining to how u-boot 
>> detects memory size of an mmc device. However, I am not 100% sure, my solution 
>> conforms to the JEDEC standard. So I am putting it up for discussion.
>>
>> Previously, sector count indicated by mmc devices in the EXT_CSD
>> would only be used in u-boot if the size indicated is greater than
>> 2 GB. This seems to be incorrect. I am working with a 4 GB Micron
>> eMMC device that after partition configuration and setting the
>> user data area to enhanced mode has a remaining capacity of less
>> than 2 GB for the user data area. JESD84-B50 explicitly states in
>> 6.2.4 that for these devices SEC_CNT from the EXT_CSD is still
>> valid even if the memory size for that device has dropped below
>> 2 GB by the partition configuration applied. The access mode bits
>>from the OCR register seem to provide a better way to decide
>> whether to use the CSD-based C_SIZE & C_MULT or the EXT_CSD-based
>> SEC_CNT information when determining the device's capacity.
>>
>> In particular, this fixes a bug where u-boot SPL would assign 0 to
>> mmc->block_dev.lba later on in the mmc_startup() function and
>> subsequently fail to load u-boot from that mmc due to the original
>> C_SIZE & C_MULT code assigning a 4 TB size to mmc->capacity, that
>> incorrect capacity never being overwritten by the SEC_CNT capacity
>> calculation (due to its size being less than 2 GB) and then finally
>> lldiv(mmc->capacity, mmc->read_bl_len) exceeding the 32-bit result
>> data type of mmc->block_dev.lba.
>>
>> Signed-off-by: Frank Bormann <fbormann at yahoo.com>
>> ---
>>  drivers/mmc/mmc.c |   10 +++++-----
>>  include/mmc.h     |    1 +
>>  2 files changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>> index c6a1c23..c5d1efc 100644
>> --- a/drivers/mmc/mmc.c
>> +++ b/drivers/mmc/mmc.c
>> @@ -935,19 +935,19 @@ static int mmc_startup(struct mmc *mmc)
>>         if (!IS_SD(mmc) && (mmc->version >= MMC_VERSION_4)) {
>>                 /* check  ext_csd version and capacity */
>>                 err = mmc_send_ext_csd(mmc, ext_csd);
>> -               if (!err && (ext_csd[EXT_CSD_REV] >= 2)) {
>> +               if (!err && (ext_csd[EXT_CSD_REV] >= 2) &&
>> +                       (mmc->ocr & OCR_ACCESS_MODE) == OCR_ACCESS_BY_SECTOR) {
>>                         /*
>>                          * According to the JEDEC Standard, the value of
>> -                        * ext_csd's capacity is valid if the value is more
>> -                        * than 2GB
>> +                        * ext_csd's capacity is valid if the device addresses
>> +                        * its memory by sector
>>                          */
>>                         capacity = ext_csd[EXT_CSD_SEC_CNT] << 0
>>                                         | ext_csd[EXT_CSD_SEC_CNT + 1] << 8
>>                                         | ext_csd[EXT_CSD_SEC_CNT + 2] << 16
>>                                         | ext_csd[EXT_CSD_SEC_CNT + 3] << 24;
>>                         capacity *= MMC_MAX_BLOCK_LEN;
>> -                       if ((capacity >> 20) > 2 * 1024)
>> -                               mmc->capacity_user = capacity;
>> +                       mmc->capacity_user = capacity;
>>                 }
>>
>>                 switch (ext_csd[EXT_CSD_REV]) {
>> diff --git a/include/mmc.h b/include/mmc.h
>> index e1060b9..816b580 100644
>> --- a/include/mmc.h
>> +++ b/include/mmc.h
>> @@ -104,6 +104,7 @@
>>  #define OCR_HCS                        0x40000000
>>  #define OCR_VOLTAGE_MASK       0x007FFF80
>>  #define OCR_ACCESS_MODE                0x60000000
>> +#define OCR_ACCESS_BY_SECTOR   (1 << 30)
>>
>>  #define SECURE_ERASE           0x80000000
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