mmc: sdhci-omap: Add card_busy host ops

Add card_busy host ops in sdhci_omap to check card busy status.

The voltage switching sequence for AM572x platform is mentioned
in Figure 25-48. eMMC/SD/SDIO Power Switching Procedure of
AM572x Sitara Processors Silicon Revision 2.0, 1.1 TRM
(SPRUHZ6I - October 2014–Revised April 2017 [1]).

In the voltage switching sequence, CLKEXTFREE bit in MMCHS_CON
should also be set after switching to 1.8v which is also taken
care in the card_busy ops.

[1] -> http://www.ti.com/lit/ug/spruhz6i/spruhz6i.pdf

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
index 96985786cadf..df927f3faaf6 100644
--- a/drivers/mmc/host/sdhci-omap.c
+++ b/drivers/mmc/host/sdhci-omap.c
@@ -31,11 +31,17 @@
 #define SDHCI_OMAP_CON          0x12c
 #define CON_DW8                 BIT(5)
 #define CON_DMA_MASTER          BIT(20)
+#define CON_CLKEXTFREE          BIT(16)
+#define CON_PADEN               BIT(15)
 #define CON_INIT                BIT(1)
 #define CON_OD                  BIT(0)
 
 #define SDHCI_OMAP_CMD          0x20c
 
+#define SDHCI_OMAP_PSTATE       0x0224
+#define PSTATE_DLEV_DAT0        BIT(20)
+#define PSTATE_DATI             BIT(1)
+
 #define SDHCI_OMAP_HCTL         0x228
 #define HCTL_SDBP               BIT(8)
 #define HCTL_SDVS_SHIFT         9
@@ -191,6 +197,51 @@ static void sdhci_omap_conf_bus_power(struct sdhci_omap_host *omap_host,
         }
 }
 
+static int sdhci_omap_card_busy(struct mmc_host *mmc)
+{
+        u32 reg, ac12;
+        int ret = false;
+        struct sdhci_host *host = mmc_priv(mmc);
+        struct sdhci_pltfm_host *pltfm_host;
+        struct sdhci_omap_host *omap_host;
+        u32 ier = host->ier;
+
+        pltfm_host = sdhci_priv(host);
+        omap_host = sdhci_pltfm_priv(pltfm_host);
+
+        reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_CON);
+        ac12 = sdhci_omap_readl(omap_host, SDHCI_OMAP_AC12);
+        reg &= ~CON_CLKEXTFREE;
+        if (ac12 & AC12_V1V8_SIGEN)
+                reg |= CON_CLKEXTFREE;
+        reg |= CON_PADEN;
+        sdhci_omap_writel(omap_host, SDHCI_OMAP_CON, reg);
+
+        disable_irq(host->irq);
+        ier |= SDHCI_INT_CARD_INT;
+        sdhci_writel(host, ier, SDHCI_INT_ENABLE);
+        sdhci_writel(host, ier, SDHCI_SIGNAL_ENABLE);
+
+        /*
+         * Delay is required for PSTATE to correctly reflect
+         * DLEV/CLEV values after PADEN is set.
+         */
+        usleep_range(50, 100);
+        reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_PSTATE);
+        if ((reg & PSTATE_DATI) || !(reg & PSTATE_DLEV_DAT0))
+                ret = true;
+
+        reg = sdhci_omap_readl(omap_host, SDHCI_OMAP_CON);
+        reg &= ~(CON_CLKEXTFREE | CON_PADEN);
+        sdhci_omap_writel(omap_host, SDHCI_OMAP_CON, reg);
+
+        sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+        sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+        enable_irq(host->irq);
+
+        return ret;
+}
+
 static int sdhci_omap_start_signal_voltage_switch(struct mmc_host *mmc,
                                                   struct mmc_ios *ios)
 {
@@ -562,6 +613,7 @@ static int sdhci_omap_probe(struct platform_device *pdev)
         host->mmc_host_ops.start_signal_voltage_switch =
                                         sdhci_omap_start_signal_voltage_switch;
         host->mmc_host_ops.set_ios = sdhci_omap_set_ios;
+        host->mmc_host_ops.card_busy = sdhci_omap_card_busy;
 
         sdhci_read_caps(host);
         host->caps |= SDHCI_CAN_DO_ADMA2;