mmc: sdhci: Add sd host v4 mode

For SD host controller version 4.00 or later ones, there're two
modes of implementation - Version 3.00 compatible mode or
Version 4 mode.  This patch introduced an interface to enable
v4 mode.

Signed-off-by: Chunyan Zhang <zhang.chunyan@linaro.org>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f22a89b..c067cd5 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -123,6 +123,29 @@ EXPORT_SYMBOL_GPL(sdhci_dumpregs);
  *                                                                           *
 \*****************************************************************************/
 
+static void sdhci_do_enable_v4_mode(struct sdhci_host *host)
+{
+       u16 ctrl2;
+
+       ctrl2 = sdhci_readb(host, SDHCI_HOST_CONTROL2);
+       if (ctrl2 & SDHCI_CTRL_V4_MODE)
+               return;
+
+       ctrl2 |= SDHCI_CTRL_V4_MODE;
+       sdhci_writeb(host, ctrl2, SDHCI_HOST_CONTROL);
+}
+
+/*
+ * This can be called before sdhci_add_host() by Vendor's host controller
+ * driver to enable v4 mode if supported.
+ */
+void sdhci_enable_v4_mode(struct sdhci_host *host)
+{
+       host->v4_mode = true;
+       sdhci_do_enable_v4_mode(host);
+}
+EXPORT_SYMBOL_GPL(sdhci_enable_v4_mode);
+
 static inline bool sdhci_data_line_cmd(struct mmc_command *cmd)
 {
        return cmd->data || cmd->flags & MMC_RSP_BUSY;
@@ -252,6 +275,9 @@ static void sdhci_init(struct sdhci_host *host, int soft)
        else
                sdhci_do_reset(host, SDHCI_RESET_ALL);
 
+       if (host->v4_mode)
+               sdhci_do_enable_v4_mode(host);
+
        sdhci_set_default_irqs(host);
 
        host->cqe_on = false;
@@ -3394,6 +3420,9 @@ void __sdhci_read_caps(struct sdhci_host *host, u16 *ver, u32 *caps, u32 *caps1)
 
        sdhci_do_reset(host, SDHCI_RESET_ALL);
 
+       if (host->v4_mode)
+               sdhci_do_enable_v4_mode(host);
+
        of_property_read_u64(mmc_dev(host->mmc)->of_node,
                             "sdhci-caps-mask", &dt_caps_mask);
        of_property_read_u64(mmc_dev(host->mmc)->of_node,

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 3f4f4cf..c4805dc 100644 (file)
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -184,6 +184,7 @@
 #define   SDHCI_CTRL_DRV_TYPE_D                0x0030
 #define  SDHCI_CTRL_EXEC_TUNING                0x0040
 #define  SDHCI_CTRL_TUNED_CLK          0x0080
+#define  SDHCI_CTRL_V4_MODE            0x1000
 #define  SDHCI_CTRL_PRESET_VAL_ENABLE  0x8000
 
 #define SDHCI_CAPABILITIES     0x40
@@ -504,6 +505,7 @@ struct sdhci_host {
        bool preset_enabled;    /* Preset is enabled */
        bool pending_reset;     /* Cmd/data reset is pending */
        bool irq_wake_enabled;  /* IRQ wakeup is enabled */
+       bool v4_mode;           /* Host Version 4 Enable */
 
        struct mmc_request *mrqs_done[SDHCI_MAX_MRQS];  /* Requests done */
        struct mmc_command *cmd;        /* Current command */
@@ -759,6 +761,7 @@ bool sdhci_cqe_irq(struct sdhci_host *host, u32 intmask, int *cmd_error,
                   int *data_error);
 
 void sdhci_dumpregs(struct sdhci_host *host);
+void sdhci_enable_v4_mode(struct sdhci_host *host);
 
 void sdhci_start_tuning(struct sdhci_host *host);
 void sdhci_end_tuning(struct sdhci_host *host);