[U-Boot] [PATCH] mmc: modified calculated mmc-capacity & set mmc trans_speed

[Minkyu Kang]

Dear Andy,

On 7 May 2010 16:52, Andy Fleming <afleming at gmail.com> wrote:
> On Fri, May 7, 2010 at 1:45 AM, Jae hoon Chung <jh80.chung at gmail.com> wrote:
>> Dear Andy
>>
>> Thanks for your comment..
>> but i have some question...
>>
>> 2010/5/7 Andy Fleming <afleming at gmail.com>:
>>> On Wed, Apr 7, 2010 at 10:36 PM, Jae hoon Chung <jh80.chung at gmail.com> wrote:
>>>> The patches do the following
>>>> 1. If mmc size is more than 2GB , we need to calculated using the
>>>> extended csd register.
>>>
>>> This description is slightly inaccurate.  I have encountered MMC cards
>>> with 4GB capacity, which are not actually high-capacity cards.  But
>>> certainly there's a bug in the current code where high-capacity MMC
>>> cards are not getting proper size calculations.
>>>
>>
>> that means 4GB capacity is not high-capacity cards, right?
>> i understood that higher than 2GB is supported high-capacity..
>> if i mis-understood, i'll check the spec.
>
>
> Well, the spec says anything over 2GB is high capacity, and should be
> accessed using block addressing.  However, the 4GB card I used
> reported itself as not high-capacity, and was addressable via byte
> addressing.  This works, because 4GB is addressable that way, but it's
> technically in violation of the spec.
>
>
>>
>>>
>>>> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
>>>> index cf4ea16..c985924 100644
>>>> --- a/drivers/mmc/mmc.c
>>>> +++ b/drivers/mmc/mmc.c
>>>> @@ -410,6 +410,10 @@ int mmc_change_freq(struct mmc *mmc)
>>>>        if (ext_csd[212] || ext_csd[213] || ext_csd[214] || ext_csd[215])
>>>>                mmc->high_capacity = 1;
>>>>
>>>> +       if (mmc->high_capacity)
>>>> +               mmc->capacity = ((ext_csd[215] << 24) | (ext_csd[214] << 16) |
>>>> +                               (ext_csd[213] << 8) | ext_csd[212]);
>>>> +
>>>
>>>
>>> This is off by a factor of block size.  Capacity is supposed to be the
>>> size in bytes, and this sets it to the size in blocks, I believe.
>>>
>>> Hmm... I don't like that we are now doing the calculation twice for
>>> high-capacity MMC cards, but I guess that's fine for now, as this only
>>> affects v4 and higher, and extracting it is a bit more of a pain than
>>> I originally thought.
>>>
>>> On a side note, does this mean you have a high-capacity MMC card?  And
>>> can you point me to a place to get one?  We've been trying to test MMC
>>> high-capacity for a while, and have yet to find a real one (we found
>>> that 4GB one I mentioned, and it does normal byte-addressing).
>>>
>>
>> didn't you have high-capacity card?
>> we tested with 8GB moviNAND card, below is mmc card information using
>> that code..
>
>
> Hmm...I'm not managing to find an actual card online for sale.  Do you
> have a link?  We had a high-capacity SD card, but no MMC card.
>
>
>>
>> Tran Speed: 52000000
>> Rd Block Len: 512
>> MMC version 4.3
>> High Capacity: Yes
>> Capacity: 7840 MByte
>> Bus Width: 4-bit
>>
>> and if card is higher than 2GB, access mode selected sector mode..
>> why does card do normal byte-addressing?
>
> Yours is clearly a proper high-capacity card.  :)

So, what is the conclusion or this patch?
Modify the patch? or NAK this patch?
Please let him know.

Thanks
Minkyu Kang
-- 
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