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

[Andy Fleming]

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.


> 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).

So just multiply capacity by block size, and we can apply this.


>        cardtype = ext_csd[196] & 0xf;
>
>        err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL, EXT_CSD_HS_TIMING, 1);
> @@ -794,12 +798,11 @@ int mmc_startup(struct mmc *mmc)
>
>                if (mmc->card_caps & MMC_MODE_HS) {
>                        if (mmc->card_caps & MMC_MODE_HS_52MHz)
> -                               mmc_set_clock(mmc, 52000000);
> +                               mmc->tran_speed = 52000000;
>                        else
> -                               mmc_set_clock(mmc, 26000000);
> -               } else
> -                       mmc_set_clock(mmc, 20000000);
> -       }
> +                               mmc->tran_speed = 26000000;
> +               }
> +               mmc_set_clock(mmc, mmc->tran_speed);

This looks good.


Andy