[PATCH] mmc: fsl_esdhc: Fix 'Internal clock never stabilised.' error

[Pali Rohár]

Only newer eSDHC controllers set PRSSTAT_SDSTB flag. So do not wait until
flag PRSSTAT_SDSTB is set on old pre-2.2 controllers. Instead sleep for
fixed amount of time like it was before commit 6f883e501b65 ("mmc:
fsl_esdhc: Add emmc hs200 support").

This change fixes error 'Internal clock never stabilised.' which is printed
on P2020 board at every access to SD card.

Fixes: 6f883e501b65 ("mmc: fsl_esdhc: Add emmc hs200 support")
Signed-off-by: Pali Rohár <p...@kernel.org>
---
 drivers/mmc/fsl_esdhc.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index fdf2cc290e06..3b3587bd8d72 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -503,6 +503,7 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct 
mmc *mmc, uint clock)
        u32 time_out;
        u32 value;
        uint clk;
+       u32 hostver;
 
        if (clock < mmc->cfg->f_min)
                clock = mmc->cfg->f_min;
@@ -543,6 +544,14 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct 
mmc *mmc, uint clock)
 
        esdhc_clrsetbits32(&regs->sysctl, SYSCTL_CLOCK_MASK, clk);
 
+       /* Only newer eSDHC controllers set PRSSTAT_SDSTB flag */
+       hostver = esdhc_read32(&priv->esdhc_regs->hostver);
+       if (HOSTVER_VENDOR(hostver) <= VENDOR_V_22) {
+               udelay(10000);
+               esdhc_setbits32(&regs->sysctl, SYSCTL_PEREN | SYSCTL_CKEN);
+               return;
+       }
+
        time_out = 20;
        value = PRSSTAT_SDSTB;
        while (!(esdhc_read32(&regs->prsstat) & value)) {
@@ -562,6 +571,7 @@ static void esdhc_clock_control(struct fsl_esdhc_priv 
*priv, bool enable)
        struct fsl_esdhc *regs = priv->esdhc_regs;
        u32 value;
        u32 time_out;
+       u32 hostver;
 
        value = esdhc_read32(&regs->sysctl);
 
@@ -572,6 +582,13 @@ static void esdhc_clock_control(struct fsl_esdhc_priv 
*priv, bool enable)
 
        esdhc_write32(&regs->sysctl, value);
 
+       /* Only newer eSDHC controllers set PRSSTAT_SDSTB flag */
+       hostver = esdhc_read32(&priv->esdhc_regs->hostver);
+       if (HOSTVER_VENDOR(hostver) <= VENDOR_V_22) {
+               udelay(10000);
+               return;
+       }
+
        time_out = 20;
        value = PRSSTAT_SDSTB;
        while (!(esdhc_read32(&regs->prsstat) & value)) {
-- 
2.20.1