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mmc: core: eMMC bus width may not work on all platforms

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CMD19 -- The offical way to validate bus widths from the JEDEC spec
does not work on all platforms.  Some platforms that use PCI/PCIe
to connect their SD controllers are known to fail.

If the quirk MMC_BUS_WIDTH_TEST is not defined we try to figure out
the bus width by reading the ext_csd at different bus widths and
compare this against the ext_csd read in 1 bit mode.  If no ext_csd
is available we default to 1 bit operations.

Code has been tested on mmp2 against 8 bit eMMC and Transcend 2GB
card that is known to not work in 4 bit mode.  The physical pins
on the card are not present to support 4 bit operation.

Signed-off-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Philip Rakity 2011-05-24 18:14:58 -07:00 committed by Chris Ball
parent 4f3d3e9b50
commit 08ee80cc39
1 changed files with 103 additions and 11 deletions
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114
drivers/mmc/core/mmc.c
View File

@ -174,14 +174,17 @@ static int mmc_decode_csd(struct mmc_card *card)
}
/*
* Read and decode extended CSD.
* Read extended CSD.
*/
static int mmc_read_ext_csd(struct mmc_card *card)
static int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd)
{
int err;
u8 *ext_csd;
BUG_ON(!card);
BUG_ON(!new_ext_csd);
*new_ext_csd = NULL;
if (card->csd.mmca_vsn < CSD_SPEC_VER_4)
return 0;
@ -199,12 +202,15 @@ static int mmc_read_ext_csd(struct mmc_card *card)
err = mmc_send_ext_csd(card, ext_csd);
if (err) {
kfree(ext_csd);
*new_ext_csd = NULL;
/* If the host or the card can't do the switch,
* fail more gracefully. */
if ((err != -EINVAL)
&& (err != -ENOSYS)
&& (err != -EFAULT))
goto out;
return err;
/*
* High capacity cards should have this "magic" size
@ -222,9 +228,23 @@ static int mmc_read_ext_csd(struct mmc_card *card)
mmc_hostname(card->host));
err = 0;
}
} else
*new_ext_csd = ext_csd;
goto out;
}
return err;
}
/*
* Decode extended CSD.
*/
static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
{
int err = 0;
BUG_ON(!card);
if (!ext_csd)
return 0;
/* Version is coded in the CSD_STRUCTURE byte in the EXT_CSD register */
if (card->csd.structure == 3) {
@ -372,8 +392,69 @@ static int mmc_read_ext_csd(struct mmc_card *card)
card->erased_byte = 0x0;
out:
kfree(ext_csd);
return err;
}
static inline void mmc_free_ext_csd(u8 *ext_csd)
{
kfree(ext_csd);
}
static int mmc_compare_ext_csds(struct mmc_card *card, u8 *ext_csd,
unsigned bus_width)
{
u8 *bw_ext_csd;
int err;
err = mmc_get_ext_csd(card, &bw_ext_csd);
if (err)
return err;
if ((ext_csd == NULL || bw_ext_csd == NULL)) {
if (bus_width != MMC_BUS_WIDTH_1)
err = -EINVAL;
goto out;
}
if (bus_width == MMC_BUS_WIDTH_1)
goto out;
/* only compare read only fields */
err = (!(ext_csd[EXT_CSD_PARTITION_SUPPORT] ==
bw_ext_csd[EXT_CSD_PARTITION_SUPPORT]) &&
(ext_csd[EXT_CSD_ERASED_MEM_CONT] ==
bw_ext_csd[EXT_CSD_ERASED_MEM_CONT]) &&
(ext_csd[EXT_CSD_REV] ==
bw_ext_csd[EXT_CSD_REV]) &&
(ext_csd[EXT_CSD_STRUCTURE] ==
bw_ext_csd[EXT_CSD_STRUCTURE]) &&
(ext_csd[EXT_CSD_CARD_TYPE] ==
bw_ext_csd[EXT_CSD_CARD_TYPE]) &&
(ext_csd[EXT_CSD_S_A_TIMEOUT] ==
bw_ext_csd[EXT_CSD_S_A_TIMEOUT]) &&
(ext_csd[EXT_CSD_HC_WP_GRP_SIZE] ==
bw_ext_csd[EXT_CSD_HC_WP_GRP_SIZE]) &&
(ext_csd[EXT_CSD_ERASE_TIMEOUT_MULT] ==
bw_ext_csd[EXT_CSD_ERASE_TIMEOUT_MULT]) &&
(ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE] ==
bw_ext_csd[EXT_CSD_HC_ERASE_GRP_SIZE]) &&
(ext_csd[EXT_CSD_SEC_TRIM_MULT] ==
bw_ext_csd[EXT_CSD_SEC_TRIM_MULT]) &&
(ext_csd[EXT_CSD_SEC_ERASE_MULT] ==
bw_ext_csd[EXT_CSD_SEC_ERASE_MULT]) &&
(ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT] ==
bw_ext_csd[EXT_CSD_SEC_FEATURE_SUPPORT]) &&
(ext_csd[EXT_CSD_TRIM_MULT] ==
bw_ext_csd[EXT_CSD_TRIM_MULT]) &&
memcmp(&ext_csd[EXT_CSD_SEC_CNT],
&bw_ext_csd[EXT_CSD_SEC_CNT],
4) != 0);
if (err)
err = -EINVAL;
out:
mmc_free_ext_csd(bw_ext_csd);
return err;
}
@ -438,6 +519,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
u32 cid[4];
unsigned int max_dtr;
u32 rocr;
u8 *ext_csd = NULL;
BUG_ON(!host);
WARN_ON(!host->claimed);
@ -536,7 +618,11 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
/*
* Fetch and process extended CSD.
*/
err = mmc_read_ext_csd(card);
err = mmc_get_ext_csd(card, &ext_csd);
if (err)
goto free_card;
err = mmc_read_ext_csd(card, ext_csd);
if (err)
goto free_card;
@ -676,14 +762,18 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
0);
if (!err) {
mmc_set_bus_width(card->host, bus_width);
/*
* If controller can't handle bus width test,
* use the highest bus width to maintain
* compatibility with previous MMC behavior.
* compare ext_csd previously read in 1 bit mode
* against ext_csd at new bus width
*/
if (!(host->caps & MMC_CAP_BUS_WIDTH_TEST))
break;
err = mmc_bus_test(card, bus_width);
err = mmc_compare_ext_csds(card,
ext_csd,
bus_width);
else
err = mmc_bus_test(card, bus_width);
if (!err)
break;
}
@ -730,12 +820,14 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
if (!oldcard)
host->card = card;
mmc_free_ext_csd(ext_csd);
return 0;
free_card:
if (!oldcard)
mmc_remove_card(card);
err:
mmc_free_ext_csd(ext_csd);
return err;
}