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authorAndrew Gabbasov <andrew_gabbasov@mentor.com>2014-12-25 10:22:25 -0600
committerPantelis Antoniou <pantelis.antoniou@konsulko.com>2015-01-19 17:41:52 +0200
commitfc5b32fbf3bd43dabaf409e424e0bfb9a1b4df26 (patch)
tree534a345ad2ff73c1a2b81acd73e20a027f5d9ed6 /drivers
parentbf4770731c1fbd23befb1ffcd0436df2262a3199 (diff)
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mmc: Skip changing bus width for MMC cards earlier than version 4.0
Wider bus widths (larger than default 1 bit) appeared in MMC standard version 4.0. So, for MMC cards of any earlier version trying to change the bus width (including ext_csd comparison) does not make any sense. It may work incorrectly and at least cause unnecessary timeouts. So, just skip the entire bus width related activity for earlier versions. Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com> Tested-by: Alexey Brodkin <abrodkin@synopsys.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mmc/mmc.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index bdd7894231..b8039cd092 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -486,7 +486,7 @@ static int mmc_change_freq(struct mmc *mmc)
char cardtype;
int err;
- mmc->card_caps = MMC_MODE_4BIT | MMC_MODE_8BIT;
+ mmc->card_caps = 0;
if (mmc_host_is_spi(mmc))
return 0;
@@ -495,6 +495,8 @@ static int mmc_change_freq(struct mmc *mmc)
if (mmc->version < MMC_VERSION_4)
return 0;
+ mmc->card_caps |= MMC_MODE_4BIT | MMC_MODE_8BIT;
+
err = mmc_send_ext_csd(mmc, ext_csd);
if (err)
@@ -1349,7 +1351,8 @@ static int mmc_startup(struct mmc *mmc)
mmc->tran_speed = 50000000;
else
mmc->tran_speed = 25000000;
- } else {
+ } else if (mmc->version >= MMC_VERSION_4) {
+ /* Only version 4 of MMC supports wider bus widths */
int idx;
/* An array of possible bus widths in order of preference */