[PATCH] mmc: sdhci-msm: Add support for UHS cards

From: Georgi Djakov
Date: Fri Jun 24 2016 - 11:07:24 EST


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@xxxxxxxxxx>
---
drivers/mmc/host/sdhci-msm.c | 66 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 0653fe730150..ac5700233e12 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -32,6 +32,21 @@
#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 +71,7 @@
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 +426,39 @@ 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 +472,7 @@ 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 = {
@@ -545,6 +595,22 @@ 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;