On 2012-11-02, victor victor@keyasic.com wrote:
Hi All,
Accord to SD spec 2.0, the formula to find out sd card capacity is:
memory capacity = (C_SIZE+1) * 512K byte and C_SIZE is from CSD [69:48]
Thus, the code in generic mmc is wrong for the high capacity sd card. My patch is below.
We should be careful about the fact that this only works for SD cards. The size parameter is handled differently on MMC devices larger than 2 GiB. What do you think of the following patch:
(Compile tested only, I do not have a board available for testing right now)
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From 206b32c0bc90972b3dab2fe7ef902a451fc8e7b6 Mon Sep 17 00:00:00 2001
From: Romain Izard romain.izard.pro@gmail.com Date: Mon, 5 Nov 2012 10:52:56 +0100 Subject: [PATCH] mmc: Correct computing the SD capacity
For high-capacity SD cards, the block size is not used to compute the effective card capacity. Since high capacity MMC cards do not use the same method, high-capacity SD cards must be adressed separately.
Signed-off-by: Romain Izard romain.izard.pro@gmail.com --- drivers/mmc/mmc.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c index 5ffd8c5..209a200 100644 --- a/drivers/mmc/mmc.c +++ b/drivers/mmc/mmc.c @@ -976,19 +976,18 @@ static int mmc_startup(struct mmc *mmc) else mmc->write_bl_len = 1 << ((cmd.response[3] >> 22) & 0xf);
- if (mmc->high_capacity) { + if (IS_SD(mmc) && mmc->high_capacity) { csize = (mmc->csd[1] & 0x3f) << 16 | (mmc->csd[2] & 0xffff0000) >> 16; - cmult = 8; + mmc->capacity = (csize + 1) << 19; } else { csize = (mmc->csd[1] & 0x3ff) << 2 | (mmc->csd[2] & 0xc0000000) >> 30; cmult = (mmc->csd[2] & 0x00038000) >> 15; + mmc->capacity = (csize + 1) << (cmult + 2); + mmc->capacity *= mmc->read_bl_len; }
- mmc->capacity = (csize + 1) << (cmult + 2); - mmc->capacity *= mmc->read_bl_len; - if (mmc->read_bl_len > 512) mmc->read_bl_len = 512;