diff options
| author | Anssi Hannula <anssi.hannula@bitwise.fi> | 2017-02-13 13:46:41 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-23 17:43:10 +0100 |
| commit | 5a86b1150f6ce88c43d669bfe14c96b312a1cceb (patch) | |
| tree | 82d5f3a980f482fff13e691f2144072f43d292ef /drivers/mmc | |
| parent | 6f26f0ba2435a49179b5f9c452afde0600e24987 (diff) | |
mmc: core: fix multi-bit bus width without high-speed mode
commit 3d4ef329757cfd5e0b23cce97cdeca7e2df89c99 upstream.
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>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
[anssi.hannula@bitwise.fi: backported for the different err variable
check on v4.4 and tested]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/core/mmc.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index 78187699467a..79a0c26e1419 100644 --- a/drivers/mmc/core/mmc.c +++ b/drivers/mmc/core/mmc.c @@ -1581,10 +1581,10 @@ 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 (!IS_ERR_VALUE(err)) { + if (!IS_ERR_VALUE(err) && mmc_card_hs(card)) { err = mmc_select_hs_ddr(card); if (err) goto free_card; |