mmc: tmio: sdhi: Skip bad taps

Some of the tuning taps produce suboptimal results. Add code
which skips those "bad" taps.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>

diff --git a/drivers/mmc/renesas-sdhi.c b/drivers/mmc/renesas-sdhi.c
index dcc77dd..087d8b4 100644 (file)
--- a/drivers/mmc/renesas-sdhi.c
+++ b/drivers/mmc/renesas-sdhi.c
@@ -97,6 +97,7 @@ static bool renesas_sdhi_check_scc_error(struct udevice *dev)
        struct tmio_sd_priv *priv = dev_get_priv(dev);
        struct mmc *mmc = mmc_get_mmc_dev(dev);
        unsigned long new_tap = priv->tap_set;
+       unsigned long error_tap = priv->tap_set;
        u32 reg, smpcmp;
 
        if ((priv->caps & TMIO_SD_CAP_RCAR_UHS) &&
@@ -140,15 +141,32 @@ static bool renesas_sdhi_check_scc_error(struct udevice *dev)
                case RENESAS_SDHI_SCC_SMPCMP_CMD_REQUP:
                        new_tap = (priv->tap_set +
                                   priv->tap_num + 1) % priv->tap_num;
+                       error_tap = (priv->tap_set +
+                                    priv->tap_num - 1) % priv->tap_num;
                        break;
                case RENESAS_SDHI_SCC_SMPCMP_CMD_REQDOWN:
                        new_tap = (priv->tap_set +
                                   priv->tap_num - 1) % priv->tap_num;
+                       error_tap = (priv->tap_set +
+                                    priv->tap_num + 1) % priv->tap_num;
                        break;
                default:
                        return true;    /* Need re-tune */
                }
 
+               if (priv->hs400_bad_tap & BIT(new_tap)) {
+                       /*
+                        * New tap is bad tap (cannot change).
+                        * Compare with HS200 tuning result.
+                        * In HS200 tuning, when smpcmp[error_tap]
+                        * is OK, retune is executed.
+                        */
+                       if (priv->smpcmp & BIT(error_tap))
+                               return true;    /* Need retune */
+
+                       return false;   /* cannot change */
+               }
+
                priv->tap_set = new_tap;
        } else {
                if (reg & RENESAS_SDHI_SCC_RVSREQ_RVSERR)
@@ -303,6 +321,7 @@ static int renesas_sdhi_hs400(struct udevice *dev)
        struct mmc *mmc = mmc_get_mmc_dev(dev);
        bool hs400 = (mmc->selected_mode == MMC_HS_400);
        int ret, taps = hs400 ? priv->nrtaps : 8;
+       unsigned long new_tap;
        u32 reg;
 
        if (taps == 4)  /* HS400 on 4tap SoC needs different clock */
@@ -335,6 +354,24 @@ static int renesas_sdhi_hs400(struct udevice *dev)
                             RENESAS_SDHI_SCC_DTCNTL_TAPEN,
                             RENESAS_SDHI_SCC_DTCNTL);
 
+       /* Avoid bad TAP */
+       if (priv->hs400_bad_tap & BIT(priv->tap_set)) {
+               new_tap = (priv->tap_set +
+                          priv->tap_num + 1) % priv->tap_num;
+
+               if (priv->hs400_bad_tap & BIT(new_tap))
+                       new_tap = (priv->tap_set +
+                                  priv->tap_num - 1) % priv->tap_num;
+
+               if (priv->hs400_bad_tap & BIT(new_tap)) {
+                       new_tap = priv->tap_set;
+                       debug("Three consecutive bad tap is prohibited\n");
+               }
+
+               priv->tap_set = new_tap;
+               tmio_sd_writel(priv, priv->tap_set, RENESAS_SDHI_SCC_TAPSET);
+       }
+
        if (taps == 4) {
                tmio_sd_writel(priv, priv->tap_set >> 1,
                               RENESAS_SDHI_SCC_TAPSET);
@@ -682,13 +719,23 @@ static void renesas_sdhi_filter_caps(struct udevice *dev)
            (rmobile_get_cpu_rev_fraction() <= 2)))
                plat->cfg.host_caps &= ~MMC_MODE_HS400;
 
-       /* M3W ES1.x for x>2 can use HS400 with manual adjustment */
+       /* H3 ES2.0, ES3.0 and M3W ES1.2 and M3N bad taps */
+       if (((rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A7795) &&
+           (rmobile_get_cpu_rev_integer() >= 2)) ||
+           ((rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A7796) &&
+           (rmobile_get_cpu_rev_integer() == 1) &&
+           (rmobile_get_cpu_rev_fraction() == 2)) ||
+           (rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A77965))
+               priv->hs400_bad_tap = BIT(2) | BIT(3) | BIT(6) | BIT(7);
+
+       /* M3W ES1.x for x>2 can use HS400 with manual adjustment and taps */
        if ((rmobile_get_cpu_type() == RMOBILE_CPU_TYPE_R8A7796) &&
            (rmobile_get_cpu_rev_integer() == 1) &&
            (rmobile_get_cpu_rev_fraction() > 2)) {
                priv->adjust_hs400_enable = true;
                priv->adjust_hs400_offset = 3;
                priv->adjust_hs400_calibrate = 0x9;
+               priv->hs400_bad_tap = BIT(1) | BIT(3) | BIT(5) | BIT(7);
        }
 
        /* M3N can use HS400 with manual adjustment */

diff --git a/drivers/mmc/tmio-common.h b/drivers/mmc/tmio-common.h
index 79f51d2..f39118e 100644 (file)
--- a/drivers/mmc/tmio-common.h
+++ b/drivers/mmc/tmio-common.h
@@ -145,6 +145,7 @@ struct tmio_sd_priv {
        bool                            adjust_hs400_enable;
        u8                              adjust_hs400_offset;
        u8                              adjust_hs400_calibrate;
+       u8                              hs400_bad_tap;
 #endif
        ulong (*clk_get_rate)(struct tmio_sd_priv *);
 };