mmc: mmci: stm32: Check when the voltage switch procedure should be done

If the card has not been power cycled, it may still be using 1.8V
signaling. This situation is detected in mmc_sd_init_card function and
should be handled in mmci stm32 variant.  The host->pwr_reg variable is
also correctly protected with spin locks.

Fixes: 94b94a93e355 ("mmc: mmci_sdmmc: Implement signal voltage callbacks")
Signed-off-by: Christophe Kerello <christophe.kerello@foss.st.com>
Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210701143353.13188-1-yann.gautier@foss.st.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index 51db30a..fdaa11f 100644 (file)
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -479,8 +479,9 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
        u32 status;
        int ret = 0;
 
-       if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
-               spin_lock_irqsave(&host->lock, flags);
+       spin_lock_irqsave(&host->lock, flags);
+       if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180 &&
+           host->pwr_reg & MCI_STM32_VSWITCHEN) {
                mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
                spin_unlock_irqrestore(&host->lock, flags);
 
@@ -492,9 +493,11 @@ static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
 
                writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
                               host->base + MMCICLEAR);
+               spin_lock_irqsave(&host->lock, flags);
                mmci_write_pwrreg(host, host->pwr_reg &
                                  ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
        }
+       spin_unlock_irqrestore(&host->lock, flags);
 
        return ret;
 }