Hi Terry,

On Mon, Mar 21, 2011 at 7:03 AM, Terry Lv r65388@freescale.com wrote:

MMC driver may wrongly regconize some 2GB eMMC as high capacity card.

This patch is based on the patch picked from community.

fc8a0985c2846292312556cba10b8a4182f55967 From: Hanumath Prasad hanumath.prasad@stericsson.com Date: Tue, 10 Aug 2010 18:01:45 -0700 Subject: [PATCH] mmc: only set blockaddressed for > 2GiB cards

A non-zero value of SEC_COUNT does not indicate that the card is sector addressed. According to the MMC specification, cards with a densitygreater than 2GiB are sector addressed.

Signed-off-by: Terry Lv r65388@freescale.com

drivers/mmc/mmc.c |    4 +++-  1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 6805b33..6f97911 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -399,7 +399,9 @@ int mmc_change_freq(struct mmc *mmc)        if (err)                return err;

• if (ext_csd[212] || ext_csd[213] || ext_csd[214] || ext_csd[215])

• /* Cards with density > 2GiB are sector addressed */
• if ((ext_csd[212] || ext_csd[213] || ext_csd[214] || ext_csd[215]) &&
• (mmc->capacity > (2u * 1024 * 1024 * 1024) / 512))

mmc->high_capacity = 1;

cardtype = ext_csd[196] & 0xf;

I have applied your patch, but, with Toshiba v4.41 2GB it doesn't work, because mmc->capacity is equal to 1962934272 and you are instead using the block's number , not byte's number. Changing the patch in the following way it works in my case.

- if (ext_csd[212] || ext_csd[213] || ext_csd[214] || ext_csd[215]) + printf ("mmc->capacity = %lu\n", (long unsigned int)mmc->capacity); + if ((ext_csd[212] || ext_csd[213] || ext_csd[214] || ext_csd[215]) && + (mmc->capacity > (2u * 1024 * 1024 * 1024))) { mmc->high_capacity = 1; + printf("Setting high capacity\n"); + }

Fixing that the situation is also better for me, in fact in my situation I was not able to read 256KB starting from sector 8 (512 bytes size). The card status reported ADDRESS_MISALIGN. That happened because mmc_read_blocks was using high_capacity addressing way, wrong for me. I've also noticed that the capacity variable (expressed in number of bytes) has to be re-calculated differently if <=2GB (high_capacity=0) or if >2GB (high_capacity=1). So capacity calculation depends on high_capacity. But curiously high_capacity depends on capacity. Not nice! Looking at JEDEC Standard No. 84-A441 at the end of pag.42 we have to use mmc_send_op_cond.

So I guess: mmc_init calls mmc_send_op_cond that set high_capacity, than it calls mmc_startup, that, with MMC_CMD_SEND_CSD command, set the capacity, using values in CSD register. So I guess that mmc_change_freq should not recalculate high_capacity.

It seems better, isn't it?

Regards, Raffaele