mmc: mmci_sdmmc: Implement signal voltage callbacks

To prepare the voltage switch procedure, the VSWITCHEN bit must be set
before sending the CMD11. To confirm completion of voltage switch, the
VSWEND flag must be checked.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200128090636.13689-9-ludovic.barre@st.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/mmci.h b/drivers/mmc/host/mmci.h
index c3bc0a3..e1a9b96 100644 (file)
--- a/drivers/mmc/host/mmci.h
+++ b/drivers/mmc/host/mmci.h
@@ -165,6 +165,7 @@
 /* Extended status bits for the STM32 variants */
 #define MCI_STM32_BUSYD0       BIT(20)
 #define MCI_STM32_BUSYD0END    BIT(21)
+#define MCI_STM32_VSWEND       BIT(25)
 
 #define MMCICLEAR              0x038
 #define MCI_CMDCRCFAILCLR      (1 << 0)
@@ -182,6 +183,9 @@
 #define MCI_ST_SDIOITC         (1 << 22)
 #define MCI_ST_CEATAENDC       (1 << 23)
 #define MCI_ST_BUSYENDC                (1 << 24)
+/* Extended clear bits for the STM32 variants */
+#define MCI_STM32_VSWENDC      BIT(25)
+#define MCI_STM32_CKSTOPC      BIT(26)
 
 #define MMCIMASK0              0x03c
 #define MCI_CMDCRCFAILMASK     (1 << 0)

diff --git a/drivers/mmc/host/mmci_stm32_sdmmc.c b/drivers/mmc/host/mmci_stm32_sdmmc.c
index fa875fe..f76e82f 100644 (file)
--- a/drivers/mmc/host/mmci_stm32_sdmmc.c
+++ b/drivers/mmc/host/mmci_stm32_sdmmc.c
@@ -32,6 +32,7 @@
 #define DLYB_CFGR_UNIT_MAX     127
 
 #define DLYB_LNG_TIMEOUT_US    1000
+#define SDMMC_VSWEND_TIMEOUT_US 10000
 
 struct sdmmc_lli_desc {
        u32 idmalar;
@@ -265,6 +266,7 @@ static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
        struct mmc_ios ios = host->mmc->ios;
        struct sdmmc_dlyb *dlyb = host->variant_priv;
 
+       /* adds OF options */
        pwr = host->pwr_reg_add;
 
        sdmmc_dlyb_input_ck(dlyb);
@@ -291,6 +293,10 @@ static void mmci_sdmmc_set_pwrreg(struct mmci_host *host, unsigned int pwr)
                writel(MCI_IRQENABLE | host->variant->start_err,
                       host->base + MMCIMASK0);
 
+               /* preserves voltage switch bits */
+               pwr |= host->pwr_reg & (MCI_STM32_VSWITCHEN |
+                                       MCI_STM32_VSWITCH);
+
                /*
                 * After a power-cycle state, we must set the SDMMC in
                 * Power-off. The SDMMC_D[7:0], SDMMC_CMD and SDMMC_CK are
@@ -456,6 +462,41 @@ static int sdmmc_execute_tuning(struct mmc_host *mmc, u32 opcode)
        return sdmmc_dlyb_phase_tuning(host, opcode);
 }
 
+static void sdmmc_pre_sig_volt_vswitch(struct mmci_host *host)
+{
+       /* clear the voltage switch completion flag */
+       writel_relaxed(MCI_STM32_VSWENDC, host->base + MMCICLEAR);
+       /* enable Voltage switch procedure */
+       mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCHEN);
+}
+
+static int sdmmc_post_sig_volt_switch(struct mmci_host *host,
+                                     struct mmc_ios *ios)
+{
+       unsigned long flags;
+       u32 status;
+       int ret = 0;
+
+       if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_180) {
+               spin_lock_irqsave(&host->lock, flags);
+               mmci_write_pwrreg(host, host->pwr_reg | MCI_STM32_VSWITCH);
+               spin_unlock_irqrestore(&host->lock, flags);
+
+               /* wait voltage switch completion while 10ms */
+               ret = readl_relaxed_poll_timeout(host->base + MMCISTATUS,
+                                                status,
+                                                (status & MCI_STM32_VSWEND),
+                                                10, SDMMC_VSWEND_TIMEOUT_US);
+
+               writel_relaxed(MCI_STM32_VSWENDC | MCI_STM32_CKSTOPC,
+                              host->base + MMCICLEAR);
+               mmci_write_pwrreg(host, host->pwr_reg &
+                                 ~(MCI_STM32_VSWITCHEN | MCI_STM32_VSWITCH));
+       }
+
+       return ret;
+}
+
 static struct mmci_host_ops sdmmc_variant_ops = {
        .validate_data = sdmmc_idma_validate_data,
        .prep_data = sdmmc_idma_prep_data,
@@ -467,6 +508,8 @@ static struct mmci_host_ops sdmmc_variant_ops = {
        .set_clkreg = mmci_sdmmc_set_clkreg,
        .set_pwrreg = mmci_sdmmc_set_pwrreg,
        .busy_complete = sdmmc_busy_complete,
+       .pre_sig_volt_switch = sdmmc_pre_sig_volt_vswitch,
+       .post_sig_volt_switch = sdmmc_post_sig_volt_switch,
 };
 
 void sdmmc_variant_init(struct mmci_host *host)