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Subject[PATCH v2 02/16] mmc: sdhci-omap: Add card_busy host ops
Date
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>
---
drivers/mmc/host/sdhci-omap.c | 52 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 52 insertions(+)

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;
--
2.11.0
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