Now everything is in place, so we can actually implement execute_tuning
for i.MX6SL or later. i.MX6Q would be possible as well, but that
requires a different manual tuning scheme which was not ported here.

Comparison copying 64M off a Samsung 8GTF4R eMMC on an i.MX8MP.
Before:

  imx8mp-hs200: time cp /dev/mmc2.2 .
  time: 1827ms

After:

  imx8mp-ddr52: time cp /dev/mmc2.2 .
  time: 647ms

Signed-off-by: Ahmad Fatoum <a.fat...@pengutronix.de>
---
 drivers/mci/imx-esdhc-common.c |   8 +-
 drivers/mci/imx-esdhc.c        | 153 ++++++++++++++++++++++++++++++++-
 2 files changed, 157 insertions(+), 4 deletions(-)

diff --git a/drivers/mci/imx-esdhc-common.c b/drivers/mci/imx-esdhc-common.c
index f51e5c6448a4..d2fd373d2313 100644
--- a/drivers/mci/imx-esdhc-common.c
+++ b/drivers/mci/imx-esdhc-common.c
@@ -336,7 +336,7 @@ int __esdhc_send_cmd(struct fsl_esdhc_host *host, struct 
mci_cmd *cmd,
                     struct mci_data *data)
 {
        u32     xfertyp, mixctrl, command;
-       u32     val, irqstat;
+       u32     val, irqflags, irqstat;
        dma_addr_t dma = SDHCI_NO_DMA;
        int ret;
 
@@ -376,9 +376,13 @@ int __esdhc_send_cmd(struct fsl_esdhc_host *host, struct 
mci_cmd *cmd,
        sdhci_write32(&host->sdhci, SDHCI_TRANSFER_MODE__COMMAND,
                      command << 16 | xfertyp);
 
+       irqflags = SDHCI_INT_CMD_COMPLETE;
+       if (mmc_op_tuning(cmd->cmdidx))
+               irqflags = SDHCI_INT_DATA_AVAIL;
+
        /* Wait for the command to complete */
        ret = esdhc_poll(host, SDHCI_INT_STATUS, irqstat,
-                        irqstat & SDHCI_INT_CMD_COMPLETE,
+                        irqstat & irqflags,
                         100 * MSECOND);
        if (ret) {
                dev_dbg(host->dev, "timeout 1\n");
diff --git a/drivers/mci/imx-esdhc.c b/drivers/mci/imx-esdhc.c
index 1c7bea3e0fa5..39ae17685a73 100644
--- a/drivers/mci/imx-esdhc.c
+++ b/drivers/mci/imx-esdhc.c
@@ -61,6 +61,14 @@
 #define ESDHC_PINCTRL_STATE_100MHZ     "state_100mhz"
 #define ESDHC_PINCTRL_STATE_200MHZ     "state_200mhz"
 
+/*
+ * Our interpretation of the SDHCI_HOST_CONTROL register
+ */
+#define ESDHC_CTRL_4BITBUS             (0x1 << 1)
+#define ESDHC_CTRL_8BITBUS             (0x2 << 1)
+#define ESDHC_CTRL_BUSWIDTH_MASK       (0x3 << 1)
+#define USDHC_GET_BUSWIDTH(c) (c & ESDHC_CTRL_BUSWIDTH_MASK)
+
 #define to_fsl_esdhc(mci)      container_of(mci, struct fsl_esdhc_host, mci)
 
 /*
@@ -137,6 +145,104 @@ static void set_sysctl(struct mci_host *mci, u32 clock, 
bool ddr)
                   10 * MSECOND);
 }
 
+static inline void esdhc_clrset_le(struct fsl_esdhc_host *host,
+                                  u32 mask, u32 val, int reg)
+{
+       void __iomem *base = host->sdhci.base + (reg & ~0x3);
+       u32 shift = (reg & 0x3) * 8;
+
+       writel(((readl(base) & ~(mask << shift)) | (val << shift)), base);
+}
+
+/* Enable the auto tuning circuit to check the CMD line and BUS line */
+static inline void usdhc_auto_tuning_mode_sel_and_en(struct fsl_esdhc_host 
*host)
+{
+       u32 buswidth, auto_tune_buswidth;
+       u32 reg;
+
+       buswidth = USDHC_GET_BUSWIDTH(sdhci_read32(&host->sdhci, 
SDHCI_HOST_CONTROL));
+
+       switch (buswidth) {
+       case ESDHC_CTRL_8BITBUS:
+               auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_8BIT_EN;
+               break;
+       case ESDHC_CTRL_4BITBUS:
+               auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_4BIT_EN;
+               break;
+       default:        /* 1BITBUS */
+               auto_tune_buswidth = ESDHC_VEND_SPEC2_AUTO_TUNE_1BIT_EN;
+               break;
+       }
+
+       esdhc_clrset_le(host, ESDHC_VEND_SPEC2_AUTO_TUNE_MODE_MASK,
+                       auto_tune_buswidth | ESDHC_VEND_SPEC2_AUTO_TUNE_CMD_EN,
+                       ESDHC_VEND_SPEC2);
+
+       reg = sdhci_read32(&host->sdhci, IMX_SDHCI_MIXCTRL);
+       reg |= MIX_CTRL_AUTO_TUNE_EN;
+       sdhci_write32(&host->sdhci, IMX_SDHCI_MIXCTRL, reg);
+}
+
+static void esdhc_reset_tuning(struct fsl_esdhc_host *host)
+{
+       u32 ctrl;
+       int ret;
+
+       /* Reset the tuning circuit */
+       if (esdhc_is_usdhc(host)) {
+               ctrl = sdhci_read32(&host->sdhci, IMX_SDHCI_MIXCTRL);
+               ctrl &= ~MIX_CTRL_AUTO_TUNE_EN;
+               if (host->socdata->flags & ESDHC_FLAG_STD_TUNING) {
+                       sdhci_write32(&host->sdhci, IMX_SDHCI_MIXCTRL, ctrl);
+                       ctrl = sdhci_read32(&host->sdhci, 
SDHCI_ACMD12_ERR__HOST_CONTROL2);
+                       ctrl &= ~MIX_CTRL_SMPCLK_SEL;
+                       ctrl &= ~MIX_CTRL_EXE_TUNE;
+                       sdhci_write32(&host->sdhci, 
SDHCI_ACMD12_ERR__HOST_CONTROL2, ctrl);
+                       /* Make sure MIX_CTRL_EXE_TUNE cleared */
+                       ret = sdhci_read32_poll_timeout(&host->sdhci, 
SDHCI_ACMD12_ERR__HOST_CONTROL2,
+                               ctrl, !(ctrl & MIX_CTRL_EXE_TUNE), 50);
+                       if (ret == -ETIMEDOUT)
+                               dev_warn(host->dev,
+                                "Warning! clear execute tuning bit failed\n");
+                       /*
+                        * SDHCI_INT_DATA_AVAIL is W1C bit, set this bit will 
clear the
+                        * usdhc IP internal logic flag 
execute_tuning_with_clr_buf, which
+                        * will finally make sure the normal data transfer 
logic correct.
+                        */
+                       ctrl = sdhci_read32(&host->sdhci, SDHCI_INT_STATUS);
+                       ctrl |= SDHCI_INT_DATA_AVAIL;
+                       sdhci_write32(&host->sdhci, SDHCI_INT_STATUS, ctrl);
+               }
+       }
+}
+
+static int usdhc_execute_tuning(struct mci_host *mci, u32 opcode)
+{
+       struct fsl_esdhc_host *host = to_fsl_esdhc(mci);
+       int err;
+
+       /*
+        * i.MX uSDHC internally already uses a fixed optimized timing for
+        * DDR50, normally does not require tuning for DDR50 mode.
+        */
+       if (host->sdhci.timing == MMC_TIMING_UHS_DDR50)
+               return 0;
+
+       /*
+        * Reset tuning circuit logic. If not, the previous tuning result
+        * will impact current tuning, make current tuning can't set the
+        * correct delay cell.
+        */
+       esdhc_reset_tuning(host);
+
+       err = sdhci_execute_tuning(&host->sdhci, opcode);
+       /* If tuning done, enable auto tuning */
+       if (!err)
+               usdhc_auto_tuning_mode_sel_and_en(host);
+
+       return err;
+}
+
 static int esdhc_change_pinstate(struct fsl_esdhc_host *host,
                                 unsigned int uhs)
 {
@@ -190,8 +296,18 @@ static void usdhc_set_timing(struct fsl_esdhc_host *host, 
enum mci_timing timing
                        sdhci_write32(&host->sdhci, IMX_SDHCI_DLL_CTRL, v);
                }
                break;
-       default:
+       case MMC_TIMING_UHS_SDR12:
+       case MMC_TIMING_UHS_SDR25:
+       case MMC_TIMING_UHS_SDR50:
+       case MMC_TIMING_UHS_SDR104:
+       case MMC_TIMING_MMC_HS:
+       case MMC_TIMING_MMC_HS200:
                sdhci_write32(&host->sdhci, IMX_SDHCI_MIXCTRL, mixctrl);
+               break;
+       case MMC_TIMING_LEGACY:
+       default:
+               esdhc_reset_tuning(host);
+               break;
        }
 
        esdhc_change_pinstate(host, timing);
@@ -432,6 +548,39 @@ static void fsl_esdhc_probe_dt(struct device *dev, struct 
fsl_esdhc_host *host)
        }
 }
 
+static bool usdhc_setup_tuning(struct fsl_esdhc_host *host)
+{
+       struct mci_host *mci = &host->mci;
+
+       if (!IS_ENABLED(CONFIG_MCI_TUNING) || !esdhc_is_usdhc(host))
+               return false;
+
+       /*
+        * clear tuning bits in case ROM has set it already
+        * We use writel, because we haven't set up SDHCI yet
+        */
+       writel(0x0, host->sdhci.base + IMX_SDHCI_MIXCTRL);
+       writel(0x0, host->sdhci.base + SDHCI_ACMD12_ERR__HOST_CONTROL2);
+       writel(0x0, host->sdhci.base + ESDHC_TUNE_CTRL_STATUS);
+
+       if (!(host->socdata->flags & ESDHC_FLAG_HS200))
+               return false;
+
+       if (host->socdata->flags & ESDHC_FLAG_MAN_TUNING) {
+               dev_dbg(host->dev, "i.MX6Q manual tuning not supported\n");
+               return false;
+       }
+
+       /*
+        * Link usdhc specific mmc_host_ops execute_tuning function,
+        * to replace the standard one in sdhci_ops.
+        */
+       mci->ops.execute_tuning = usdhc_execute_tuning;
+       mci->caps2 |= MMC_CAP2_HS200;
+
+       return true;
+}
+
 static int fsl_esdhc_probe(struct device *dev)
 {
        struct resource *iores;
@@ -477,7 +626,7 @@ static int fsl_esdhc_probe(struct device *dev)
        host->mci.hw_dev = dev;
        host->sdhci.mci = &host->mci;
 
-       if (!(host->socdata->flags & ESDHC_FLAG_HS200))
+       if (!usdhc_setup_tuning(host))
                host->sdhci.quirks2 |= SDHCI_QUIRK2_BROKEN_HS200;
 
        ret = sdhci_setup_host(&host->sdhci);
-- 
2.39.5


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