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atmel_mci: Fix data timeout value

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Calculate the data timeout based on values from the CSD instead of
just using a hardcoded DTOR value. This is a backport of a similar fix
in BSP 2.0, with one additional fix: the DTOCYC value is rounded up
instead of down.

Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
This commit is contained in:
Haavard Skinnemoen 2007-06-29 18:38:51 +02:00
parent 0ba8eed28b
commit a08458303e
1 changed files with 59 additions and 0 deletions
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59
cpu/at32ap/atmel_mci.c
View file

@ -56,6 +56,7 @@
#define MMC_DEFAULT_RCA 1
static unsigned int mmc_rca;
static int mmc_card_is_sd;
static block_dev_desc_t mmc_blkdev;
block_dev_desc_t *mmc_get_dev(int dev)
@ -373,6 +374,7 @@ static int sd_init_card(struct mmc_cid *cid, int verbose)
mmc_rca = resp[0] >> 16;
if (verbose)
printf("SD Card detected (RCA %u)\n", mmc_rca);
mmc_card_is_sd = 1;
return 0;
}
@ -407,6 +409,59 @@ static int mmc_init_card(struct mmc_cid *cid, int verbose)
return ret;
}
static void mci_set_data_timeout(struct mmc_csd *csd)
{
static const unsigned int dtomul_to_shift[] = {
0, 4, 7, 8, 10, 12, 16, 20,
};
static const unsigned int taac_exp[] = {
1, 10, 100, 1000, 10000, 100000, 1000000, 10000000,
};
static const unsigned int taac_mant[] = {
0, 10, 12, 13, 15, 60, 25, 30,
35, 40, 45, 50, 55, 60, 70, 80,
};
unsigned int timeout_ns, timeout_clks;
unsigned int e, m;
unsigned int dtocyc, dtomul;
unsigned int shift;
u32 dtor;
e = csd->taac & 0x07;
m = (csd->taac >> 3) & 0x0f;
timeout_ns = (taac_exp[e] * taac_mant[m] + 9) / 10;
timeout_clks = csd->nsac * 100;
timeout_clks += (((timeout_ns + 9) / 10)
* ((CFG_MMC_CLK_PP + 99999) / 100000) + 9999) / 10000;
if (!mmc_card_is_sd)
timeout_clks *= 10;
else
timeout_clks *= 100;
dtocyc = timeout_clks;
dtomul = 0;
while (dtocyc > 15 && dtomul < 8) {
dtomul++;
shift = dtomul_to_shift[dtomul];
dtocyc = (timeout_clks + (1 << shift) - 1) >> shift;
}
if (dtomul >= 8) {
dtomul = 7;
dtocyc = 15;
puts("Warning: Using maximum data timeout\n");
}
dtor = (MMCI_BF(DTOMUL, dtomul)
| MMCI_BF(DTOCYC, dtocyc));
mmci_writel(DTOR, dtor);
printf("mmc: Using %u cycles data timeout (DTOR=0x%x)\n",
dtocyc << shift, dtor);
}
int mmc_init(int verbose)
{
struct mmc_cid cid;
@ -421,6 +476,8 @@ int mmc_init(int verbose)
mmci_writel(IDR, ~0UL);
mci_set_mode(CFG_MMC_CLK_OD, MMC_DEFAULT_BLKLEN);
mmc_card_is_sd = 0;
ret = sd_init_card(&cid, verbose);
if (ret) {
mmc_rca = MMC_DEFAULT_RCA;
@ -436,6 +493,8 @@ int mmc_init(int verbose)
if (verbose)
mmc_dump_csd(&csd);
mci_set_data_timeout(&csd);
/* Initialize the blockdev structure */
mmc_blkdev.if_type = IF_TYPE_MMC;
mmc_blkdev.part_type = PART_TYPE_DOS;