[v3] mmc: sdhci-cadence: add HS400 enhanced strobe support

From: Piotr Sroka
Date: Mon Mar 06 2017 - 05:08:33 EST


Add support for HS400ES mode to Cadence SDHCI driver.

Signed-off-by: Piotr Sroka <piotrs@xxxxxxxxxxx>
---
Changes in v2:
- Modify enhanced strobe function to handle disabling
enhanced strobe inside the function.
Do no relay on that mmc_set_ios() is called
immediately after host->ops->hs400_enhanced_strobe(host, &host->ios).
Changes in v3:
- Few coding-style fixes were made.
---
drivers/mmc/host/sdhci-cadence.c | 57 +++++++++++++++++++++++++++++++++++-----
1 file changed, 50 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index 316cfec..48f6419 100644
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -40,6 +40,7 @@
#define SDHCI_CDNS_HRS06_MODE_MMC_DDR 0x3
#define SDHCI_CDNS_HRS06_MODE_MMC_HS200 0x4
#define SDHCI_CDNS_HRS06_MODE_MMC_HS400 0x5
+#define SDHCI_CDNS_HRS06_MODE_MMC_HS400ES 0x6

/* SRS - Slot Register Set (SDHCI-compatible) */
#define SDHCI_CDNS_SRS_BASE 0x200
@@ -64,6 +65,7 @@

struct sdhci_cdns_priv {
void __iomem *hrs_addr;
+ bool enhanced_strobe;
};

static void sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
@@ -108,11 +110,30 @@ static unsigned int sdhci_cdns_get_timeout_clock(struct sdhci_host *host)
return host->max_clk / 1000;
}

+static void sdhci_cdns_set_emmc_mode(struct sdhci_cdns_priv *priv, u32 mode)
+{
+ u32 tmp;
+
+ /* The speed mode for eMMC is selected by HRS06 register */
+ tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
+ tmp &= ~SDHCI_CDNS_HRS06_MODE_MASK;
+ tmp |= mode;
+ writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
+}
+
+static u32 sdhci_cdns_get_emmc_mode(struct sdhci_cdns_priv *priv)
+{
+ u32 tmp;
+
+ tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
+ return tmp & SDHCI_CDNS_HRS06_MODE_MASK;
+}
+
static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
unsigned int timing)
{
struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
- u32 mode, tmp;
+ u32 mode;

switch (timing) {
case MMC_TIMING_MMC_HS:
@@ -125,18 +146,17 @@ static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
mode = SDHCI_CDNS_HRS06_MODE_MMC_HS200;
break;
case MMC_TIMING_MMC_HS400:
- mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400;
+ if (priv->enhanced_strobe)
+ mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400ES;
+ else
+ mode = SDHCI_CDNS_HRS06_MODE_MMC_HS400;
break;
default:
mode = SDHCI_CDNS_HRS06_MODE_SD;
break;
}

- /* The speed mode for eMMC is selected by HRS06 register */
- tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
- tmp &= ~SDHCI_CDNS_HRS06_MODE_MASK;
- tmp |= mode;
- writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
+ sdhci_cdns_set_emmc_mode(priv, mode);

/* For SD, fall back to the default handler */
if (mode == SDHCI_CDNS_HRS06_MODE_SD)
@@ -213,6 +233,26 @@ static int sdhci_cdns_execute_tuning(struct mmc_host *mmc, u32 opcode)
return sdhci_cdns_set_tune_val(host, end_of_streak - max_streak / 2);
}

+static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
+ struct mmc_ios *ios)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+ u32 mode;
+
+ priv->enhanced_strobe = ios->enhanced_strobe;
+
+ mode = sdhci_cdns_get_emmc_mode(priv);
+
+ if (mode == SDHCI_CDNS_HRS06_MODE_MMC_HS400 && ios->enhanced_strobe)
+ sdhci_cdns_set_emmc_mode(priv,
+ SDHCI_CDNS_HRS06_MODE_MMC_HS400ES);
+
+ if (mode == SDHCI_CDNS_HRS06_MODE_MMC_HS400ES && !ios->enhanced_strobe)
+ sdhci_cdns_set_emmc_mode(priv,
+ SDHCI_CDNS_HRS06_MODE_MMC_HS400);
+}
+
static int sdhci_cdns_probe(struct platform_device *pdev)
{
struct sdhci_host *host;
@@ -240,8 +280,11 @@ static int sdhci_cdns_probe(struct platform_device *pdev)

priv = sdhci_cdns_priv(host);
priv->hrs_addr = host->ioaddr;
+ priv->enhanced_strobe = false;
host->ioaddr += SDHCI_CDNS_SRS_BASE;
host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning;
+ host->mmc_host_ops.hs400_enhanced_strobe =
+ sdhci_cdns_hs400_enhanced_strobe;

ret = mmc_of_parse(host->mmc);
if (ret)
--
2.2.2