mmc: fsl_esdhc: make sure delay chain locked for HS400

For eMMC HS400 mode, the DLL reset is a required step for mmc rescan.
This step has not been documented in reference manual, but the RM will
be fixed sooner or later.

In previous commit to support eMMC HS400,
  db8f936 mmc: fsl_esdhc: support eMMC HS400 mode

the steps to configure DLL could be found in commit message,
  13. Set DLLCFG0[DLL_ENABLE] and DLLCFG0[DLL_FREQ_SEL].
  14. Wait for delay chain to lock.

these would be fixed as,
  13.   Set DLLCFG0[DLL_ENABLE] and DLLCFG0[DLL_FREQ_SEL].
  13.1  Write DLLCFG0[DLL_RESET] to 1 and wait for 1us,
        then write DLLCFG0[DLL_RESET]
  14.   Wait for delay chain to lock.

This patch is to add the step of DLL reset, and make sure delay chain
locked for HS400.

Fixes: db8f93672b42 ("mmc: fsl_esdhc: support eMMC HS400 mode")
Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index 68130ee9f40327ae86d26d8f91094f8a7f24b4f1..a18316eda71117a17273b16210ee697f7ccd0aeb 100644 (file)
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -70,7 +70,9 @@ struct fsl_esdhc {
        uint    sdtimingctl;    /* SD timing control register */
        char    reserved8[20];  /* reserved */
        uint    dllcfg0;        /* DLL config 0 register */
-       char    reserved9[680]; /* reserved */
+       char    reserved9[12];  /* reserved */
+       uint    dllstat0;       /* DLL status 0 register */
+       char    reserved10[664];/* reserved */
        uint    esdhcctl;       /* eSDHC control register */
 };
 
@@ -617,9 +619,11 @@ static void esdhc_exit_hs400(struct fsl_esdhc_priv *priv)
        esdhc_tuning_block_enable(priv, false);
 }
 
-static void esdhc_set_timing(struct fsl_esdhc_priv *priv, enum bus_mode mode)
+static int esdhc_set_timing(struct fsl_esdhc_priv *priv, enum bus_mode mode)
 {
        struct fsl_esdhc *regs = priv->esdhc_regs;
+       ulong start;
+       u32 val;
 
        /* Exit HS400 mode before setting any other mode */
        if (esdhc_read32(&regs->tbctl) & HS400_MODE &&
@@ -640,17 +644,33 @@ static void esdhc_set_timing(struct fsl_esdhc_priv *priv, enum bus_mode mode)
                        esdhc_setbits32(&regs->dllcfg0, DLL_FREQ_SEL);
 
                esdhc_setbits32(&regs->dllcfg0, DLL_ENABLE);
+
+               esdhc_setbits32(&regs->dllcfg0, DLL_RESET);
+               udelay(1);
+               esdhc_clrbits32(&regs->dllcfg0, DLL_RESET);
+
+               start = get_timer(0);
+               val = DLL_STS_SLV_LOCK;
+               while (!(esdhc_read32(&regs->dllstat0) & val)) {
+                       if (get_timer(start) > 1000) {
+                               printf("fsl_esdhc: delay chain lock timeout\n");
+                               return -ETIMEDOUT;
+                       }
+               }
+
                esdhc_setbits32(&regs->tbctl, HS400_WNDW_ADJUST);
 
                esdhc_clock_control(priv, false);
                esdhc_flush_async_fifo(priv);
        }
        esdhc_clock_control(priv, true);
+       return 0;
 }
 
 static int esdhc_set_ios_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
 {
        struct fsl_esdhc *regs = priv->esdhc_regs;
+       int ret;
 
        if (priv->is_sdhc_per_clk) {
                /* Select to use peripheral clock */
@@ -667,7 +687,9 @@ static int esdhc_set_ios_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
                set_sysctl(priv, mmc, mmc->clock);
 
        /* Set timing */
-       esdhc_set_timing(priv, mmc->selected_mode);
+       ret = esdhc_set_timing(priv, mmc->selected_mode);
+       if (ret)
+               return ret;
 
        /* Set the bus width */
        esdhc_clrbits32(&regs->proctl, PROCTL_DTW_4 | PROCTL_DTW_8);

diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
index e6f1c75e27ca8ed471cae1915ef55648223a5080..850a304bd7dfc11cf0ebc681ee66f7cd40cbfa8f 100644 (file)
--- a/include/fsl_esdhc.h
+++ b/include/fsl_esdhc.h
@@ -187,8 +187,12 @@
 
 /* DLL config 0 register */
 #define DLL_ENABLE             0x80000000
+#define DLL_RESET              0x40000000
 #define DLL_FREQ_SEL           0x08000000
 
+/* DLL status 0 register */
+#define DLL_STS_SLV_LOCK       0x08000000
+
 #define MAX_TUNING_LOOP                40
 
 #define HOSTVER_VENDOR(x)      (((x) >> 8) & 0xff)