From: Yann Gautier yann.gautier@foss.st.com
commit 39a72dbfe188291b156dd6523511e3d5761ce775 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mmc/core/core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1641,7 +1641,13 @@ u32 mmc_select_voltage(struct mmc_host * 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"); }