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authorAnssi Hannula <anssi.hannula@bitwise.fi>2017-02-13 13:46:41 +0200
committerUlf Hansson <ulf.hansson@linaro.org>2017-02-14 08:50:10 +0100
commit3d4ef329757cfd5e0b23cce97cdeca7e2df89c99 (patch)
tree74bf597f6e43a0d85684dd1db535a29d23d4d29d /drivers/mmc
parent7089db84e356562f8ba737c29e472cc42d530dbc (diff)
downloadlinux-3d4ef329757cfd5e0b23cce97cdeca7e2df89c99.tar.bz2
mmc: core: fix multi-bit bus width without high-speed mode
Commit 577fb13199b1 ("mmc: rework selection of bus speed mode") refactored bus width selection code to mmc_select_bus_width(). However, it also altered the behavior to not call the selection code in non-high-speed modes anymore. This causes 1-bit mode to always be used when the high-speed mode is not enabled, even though 4-bit and 8-bit bus are valid bus widths in the backwards-compatibility (legacy) mode as well (see e.g. 5.3.2 Bus Speed Modes in JEDEC 84-B50). This results in a significant regression in transfer speeds. Fix the code to allow 4-bit and 8-bit widths even without high-speed mode, as before. Tested with a Zynq-7000 PicoZed 7020 board. Fixes: 577fb13199b1 ("mmc: rework selection of bus speed mode") Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi> Cc: <stable@vger.kernel.org> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/core/mmc.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index b61b52f9da3d..0fccca075e29 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1706,10 +1706,10 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
err = mmc_select_hs400(card);
if (err)
goto free_card;
- } else if (mmc_card_hs(card)) {
+ } else {
/* Select the desired bus width optionally */
err = mmc_select_bus_width(card);
- if (err > 0) {
+ if (err > 0 && mmc_card_hs(card)) {
err = mmc_select_hs_ddr(card);
if (err)
goto free_card;