How to print CMD18 read data

How to print CMD18 read data

[amit mahadik]

Hello,
         I want to interface MMC card via SPI bus. However, I am
getting CRC errors for CMD18. I tried reading partition table using
CMD17 but still get errors.
The same SDMMC card gets detected using SD interface. I want to
compare the data of CMD18/CMD17 of SD and SPI modes. Please let me
know how can I print the read data of the said commands in the block
layer?

I tried using the following code but it didn't help

sg_copy_to_buffer(brq->data.sg, brq->data.sg_len, buf, 4096); and printed buf.

Regards,
Amit.

Re: How to print CMD18 read data

[Jaehoon Chung]

Hi,

On 02/01/2017 04:23 PM, amit mahadik wrote:
> Hello,
>          I want to interface MMC card via SPI bus. However, I am
> getting CRC errors for CMD18. I tried reading partition table using
> CMD17 but still get errors.
> The same SDMMC card gets detected using SD interface. I want to
> compare the data of CMD18/CMD17 of SD and SPI modes. Please let me
> know how can I print the read data of the said commands in the block
> layer?

In my experience, CRC error was timing issue..(clock, driver-strength, etc..)
You can check those things.

Best Regards,
Jaehoon Chung

> 
> I tried using the following code but it didn't help
> 
> sg_copy_to_buffer(brq->data.sg, brq->data.sg_len, buf, 4096); and printed buf.
> 
> Regards,
> Amit.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 

Re: How to print CMD18 read data

[amit mahadik]

Hi Jaehoon,
                   Thanks for replying promptly. adding more debug
prints I see that CMD9(CSD) CMD51(SSR) values in case of SD and SPI
mode are the same. Only command that troubles is CMD18. My clock
setting is 25Mhz and the card is working at 3.3V.

Regards,
Amit.

On Wed, Feb 1, 2017 at 1:38 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
> Hi,
>
> On 02/01/2017 04:23 PM, amit mahadik wrote:
>> Hello,
>>          I want to interface MMC card via SPI bus. However, I am
>> getting CRC errors for CMD18. I tried reading partition table using
>> CMD17 but still get errors.
>> The same SDMMC card gets detected using SD interface. I want to
>> compare the data of CMD18/CMD17 of SD and SPI modes. Please let me
>> know how can I print the read data of the said commands in the block
>> layer?
>
> In my experience, CRC error was timing issue..(clock, driver-strength, etc..)
> You can check those things.
>
> Best Regards,
> Jaehoon Chung
>
>>
>> I tried using the following code but it didn't help
>>
>> sg_copy_to_buffer(brq->data.sg, brq->data.sg_len, buf, 4096); and printed buf.
>>
>> Regards,
>> Amit.
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>

Re: How to print CMD18 read data

[Jaehoon Chung]

On 02/01/2017 05:48 PM, amit mahadik wrote:
> Hi Jaehoon,
>                    Thanks for replying promptly. adding more debug
> prints I see that CMD9(CSD) CMD51(SSR) values in case of SD and SPI
> mode are the same. Only command that troubles is CMD18. My clock
> setting is 25Mhz and the card is working at 3.3V.

I don't have a knowledge about SPI mode..it might have the difference initial sequence.
How about checking "use_spi_crc"?..Someone might have much knowledge for SPI mode. :)

Best Regards,
Jaehoon Chung

> 
> Regards,
> Amit.
> 
> On Wed, Feb 1, 2017 at 1:38 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>> Hi,
>>
>> On 02/01/2017 04:23 PM, amit mahadik wrote:
>>> Hello,
>>>          I want to interface MMC card via SPI bus. However, I am
>>> getting CRC errors for CMD18. I tried reading partition table using
>>> CMD17 but still get errors.
>>> The same SDMMC card gets detected using SD interface. I want to
>>> compare the data of CMD18/CMD17 of SD and SPI modes. Please let me
>>> know how can I print the read data of the said commands in the block
>>> layer?
>>
>> In my experience, CRC error was timing issue..(clock, driver-strength, etc..)
>> You can check those things.
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> I tried using the following code but it didn't help
>>>
>>> sg_copy_to_buffer(brq->data.sg, brq->data.sg_len, buf, 4096); and printed buf.
>>>
>>> Regards,
>>> Amit.
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>>
>>
> 
> 

Re: How to print CMD18 read data

[amit mahadik]

Hi Jaehoon,
                      I tried the use_spi_crc=0 option too. However,
if the data read is incorrect the block layer has no way of knowing
the contents of partition table. That is the reason it fails to detect
partitions of the connected SDMMC card.

Regards,
Amit.

On Wed, Feb 1, 2017 at 5:13 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
> On 02/01/2017 05:48 PM, amit mahadik wrote:
>> Hi Jaehoon,
>>                    Thanks for replying promptly. adding more debug
>> prints I see that CMD9(CSD) CMD51(SSR) values in case of SD and SPI
>> mode are the same. Only command that troubles is CMD18. My clock
>> setting is 25Mhz and the card is working at 3.3V.
>
> I don't have a knowledge about SPI mode..it might have the difference initial sequence.
> How about checking "use_spi_crc"?..Someone might have much knowledge for SPI mode. :)
>
> Best Regards,
> Jaehoon Chung
>
>>
>> Regards,
>> Amit.
>>
>> On Wed, Feb 1, 2017 at 1:38 PM, Jaehoon Chung <jh80.chung@samsung.com> wrote:
>>> Hi,
>>>
>>> On 02/01/2017 04:23 PM, amit mahadik wrote:
>>>> Hello,
>>>>          I want to interface MMC card via SPI bus. However, I am
>>>> getting CRC errors for CMD18. I tried reading partition table using
>>>> CMD17 but still get errors.
>>>> The same SDMMC card gets detected using SD interface. I want to
>>>> compare the data of CMD18/CMD17 of SD and SPI modes. Please let me
>>>> know how can I print the read data of the said commands in the block
>>>> layer?
>>>
>>> In my experience, CRC error was timing issue..(clock, driver-strength, etc..)
>>> You can check those things.
>>>
>>> Best Regards,
>>> Jaehoon Chung
>>>
>>>>
>>>> I tried using the following code but it didn't help
>>>>
>>>> sg_copy_to_buffer(brq->data.sg, brq->data.sg_len, buf, 4096); and printed buf.
>>>>
>>>> Regards,
>>>> Amit.
>>>> --
>>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>>> the body of a message to majordomo@vger.kernel.org
>>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>>
>>>>
>>>
>>
>>
>

Re: How to print CMD18 read data

[David Haworth]

Hi Amit,

I'm trying to access an SD card/reader using SPI on a
Raspberry Pi. I've had a little success - some of my cards
work, some don't. I get errors from time to time, but they
appear harmless. I seem to have cured a spurious timeout
problem.

I'm using pr_info() to dump debug messages into /var/log/syslog.

Maybe we can compare notes and come up with a solution.
Contact me off-list of you prefer.

Cheers,
Dave


On Wed, Feb 01, 2017 at 05:46:34PM +0530, amit mahadik wrote:
> Hi Jaehoon,
>                       I tried the use_spi_crc=0 option too. However,
> if the data read is incorrect the block layer has no way of knowing
> the contents of partition table. That is the reason it fails to detect
> partitions of the connected SDMMC card.
> 
> Regards,
> Amit.

-- 
David Haworth
Baiersdorf, Germany
dave@fen-net.de                PGP key at https://keyserver.pgp.com/
http://thelancashireman.org