From: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx> commit dbdea70f71d672c12bc4454e7c258a8f78194d74 upstream. When enabling calibration at reset, the CALCR register was completely rewritten. This may cause certain bits being deleted unintentedly. Fix by issuing a read-modify-write operation. Fixes: 727d836a375a ("mmc: sdhci-of-at91: add DT property to enable calibration on full reset") Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200527105659.142560-1-eugen.hristev@xxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/mmc/host/sdhci-of-at91.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) --- a/drivers/mmc/host/sdhci-of-at91.c +++ b/drivers/mmc/host/sdhci-of-at91.c @@ -120,9 +120,12 @@ static void sdhci_at91_reset(struct sdhc || mmc_gpio_get_cd(host->mmc) >= 0) sdhci_at91_set_force_card_detect(host); - if (priv->cal_always_on && (mask & SDHCI_RESET_ALL)) - sdhci_writel(host, SDMMC_CALCR_ALWYSON | SDMMC_CALCR_EN, + if (priv->cal_always_on && (mask & SDHCI_RESET_ALL)) { + u32 calcr = sdhci_readl(host, SDMMC_CALCR); + + sdhci_writel(host, calcr | SDMMC_CALCR_ALWYSON | SDMMC_CALCR_EN, SDMMC_CALCR); + } } static const struct sdhci_ops sdhci_at91_sama5d2_ops = {