mmc: sdhci-msm: Add support for UHS cards

Enabling support for ultra high speed mode cards requires some
voltage switching and interaction with the PMIC via a special
power IRQ. Add support for this.

Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 90370732e7f16100c09e97896726296fd46579db..68184c7f80895ac87df6d5e31397640cc6724414 100644 (file)
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -29,9 +29,27 @@
 
 #define CORE_HC_MODE           0x78
 #define HC_MODE_EN             0x1
+
 #define CORE_POWER             0x0
 #define CORE_SW_RST            BIT(7)
 
+#define CORE_PWRCTL_STATUS     0xdc
+#define CORE_PWRCTL_MASK       0xe0
+#define CORE_PWRCTL_CLEAR      0xe4
+#define CORE_PWRCTL_CTL                0xe8
+
+#define CORE_PWRCTL_BUS_OFF    BIT(0)
+#define CORE_PWRCTL_BUS_ON     BIT(1)
+#define CORE_PWRCTL_IO_LOW     BIT(2)
+#define CORE_PWRCTL_IO_HIGH    BIT(3)
+#define CORE_PWRCTL_BUS_SUCCESS BIT(0)
+#define CORE_PWRCTL_IO_SUCCESS BIT(2)
+#define REQ_BUS_OFF            BIT(0)
+#define REQ_BUS_ON             BIT(1)
+#define REQ_IO_LOW             BIT(2)
+#define REQ_IO_HIGH            BIT(3)
+
+#define INT_MASK               0xf
 #define MAX_PHASES             16
 #define CORE_DLL_LOCK          BIT(7)
 #define CORE_DLL_EN            BIT(16)
@@ -56,6 +74,7 @@
 struct sdhci_msm_host {
        struct platform_device *pdev;
        void __iomem *core_mem; /* MSM SDCC mapped address */
+       int pwr_irq;            /* power irq */
        struct clk *clk;        /* main SD/MMC bus clock */
        struct clk *pclk;       /* SDHC peripheral bus clock */
        struct clk *bus_clk;    /* SDHC bus voter clock */
@@ -410,6 +429,39 @@ retry:
        return rc;
 }
 
+static void sdhci_msm_voltage_switch(struct sdhci_host *host)
+{
+       struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+       u32 irq_status, irq_ack = 0;
+
+       irq_status = readl_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS);
+       irq_status &= INT_MASK;
+
+       writel_relaxed(irq_status, msm_host->core_mem + CORE_PWRCTL_CLEAR);
+
+       if (irq_status & (CORE_PWRCTL_BUS_ON | CORE_PWRCTL_BUS_OFF))
+               irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
+       if (irq_status & (CORE_PWRCTL_IO_LOW | CORE_PWRCTL_IO_HIGH))
+               irq_ack |= CORE_PWRCTL_IO_SUCCESS;
+
+       /*
+        * The driver has to acknowledge the interrupt, switch voltages and
+        * report back if it succeded or not to this register. The voltage
+        * switches are handled by the sdhci core, so just report success.
+        */
+       writel_relaxed(irq_ack, msm_host->core_mem + CORE_PWRCTL_CTL);
+}
+
+static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data)
+{
+       struct sdhci_host *host = (struct sdhci_host *)data;
+
+       sdhci_msm_voltage_switch(host);
+
+       return IRQ_HANDLED;
+}
+
 static const struct of_device_id sdhci_msm_dt_match[] = {
        { .compatible = "qcom,sdhci-msm-v4" },
        {},
@@ -423,6 +475,7 @@ static const struct sdhci_ops sdhci_msm_ops = {
        .set_clock = sdhci_set_clock,
        .set_bus_width = sdhci_set_bus_width,
        .set_uhs_signaling = sdhci_set_uhs_signaling,
+       .voltage_switch = sdhci_msm_voltage_switch,
 };
 
 static const struct sdhci_pltfm_data sdhci_msm_pdata = {
@@ -546,6 +599,22 @@ static int sdhci_msm_probe(struct platform_device *pdev)
                               CORE_VENDOR_SPEC_CAPABILITIES0);
        }
 
+       /* Setup IRQ for handling power/voltage tasks with PMIC */
+       msm_host->pwr_irq = platform_get_irq_byname(pdev, "pwr_irq");
+       if (msm_host->pwr_irq < 0) {
+               dev_err(&pdev->dev, "Get pwr_irq failed (%d)\n",
+                       msm_host->pwr_irq);
+               goto clk_disable;
+       }
+
+       ret = devm_request_threaded_irq(&pdev->dev, msm_host->pwr_irq, NULL,
+                                       sdhci_msm_pwr_irq, IRQF_ONESHOT,
+                                       dev_name(&pdev->dev), host);
+       if (ret) {
+               dev_err(&pdev->dev, "Request IRQ failed (%d)\n", ret);
+               goto clk_disable;
+       }
+
        ret = sdhci_add_host(host);
        if (ret)
                goto clk_disable;