diff options
| author | Yann Gautier <yann.gautier@foss.st.com> | 2022-10-28 09:37:40 +0200 |
|---|---|---|
| committer | Ulf Hansson <ulf.hansson@linaro.org> | 2022-11-16 13:58:01 +0100 |
| commit | 39a72dbfe188291b156dd6523511e3d5761ce775 (patch) | |
| tree | 67aaa29f868c6b59a317a27b768b7cfd7a120e2b /drivers/mmc | |
| parent | Linux 6.1-rc5 (diff) | |
| download | linux-39a72dbfe188291b156dd6523511e3d5761ce775.tar.xz linux-39a72dbfe188291b156dd6523511e3d5761ce775.zip | |
mmc: core: properly select voltage range without power cycle
In mmc_select_voltage(), if there is no full power cycle, the voltage
range selected at the end of the function will be on a single range
(e.g. 3.3V/3.4V). To keep a range around the selected voltage (3.2V/3.4V),
the mask shift should be reduced by 1.
This issue was triggered by using a specific SD-card (Verbatim Premium
16GB UHS-1) on an STM32MP157C-DK2 board. This board cannot do UHS modes
and there is no power cycle. And the card was failing to switch to
high-speed mode. When adding the range 3.2V/3.3V for this card with the
proposed shift change, the card can switch to high-speed mode.
Fixes: ce69d37b7d8f ("mmc: core: Prevent violation of specs while initializing cards")
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20221028073740.7259-1-yann.gautier@foss.st.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/core/core.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 95fa8fb1d45f..c5de202f530a 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1134,7 +1134,13 @@ u32 mmc_select_voltage(struct mmc_host *host, u32 ocr) mmc_power_cycle(host, ocr); } else { bit = fls(ocr) - 1; - ocr &= 3 << bit; + /* + * The bit variable represents the highest voltage bit set in + * the OCR register. + * To keep a range of 2 values (e.g. 3.2V/3.3V and 3.3V/3.4V), + * we must shift the mask '3' with (bit - 1). + */ + ocr &= 3 << (bit - 1); if (bit != host->ios.vdd) dev_warn(mmc_dev(host), "exceeding card's volts\n"); } |