From: Elad Nachman <enachman@xxxxxxxxxxx>
Each time SD/mmc phy is initialized, at times, in some of
the attempts, phy fails to completes its initialization
which results into timeout error. Per the HW spec, it is
a pre-requisite to ensure a stable SD clock before a phy
initialization is attempted.
Signed-off-by: Elad Nachman <enachman@xxxxxxxxxxx>
---
drivers/mmc/host/sdhci-xenon-phy.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)
diff --git a/drivers/mmc/host/sdhci-xenon-phy.c b/drivers/mmc/host/sdhci-xenon-phy.c
index 8cf3a375de65..4e99197b62c3 100644
--- a/drivers/mmc/host/sdhci-xenon-phy.c
+++ b/drivers/mmc/host/sdhci-xenon-phy.c
@@ -216,6 +216,24 @@ static int xenon_alloc_emmc_phy(struct sdhci_host *host)
return 0;
}
+static int xenon_check_stability_internal_clk(struct sdhci_host *host)
+{
+ u32 reg;
+ ktime_t timeout;
+
+ /* Wait max 20 ms */
+ timeout = ktime_add_ms(ktime_get(), 20);
+ while (!((reg = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
+ & SDHCI_CLOCK_INT_STABLE)) {
+ if (ktime_after(ktime_get(), timeout)) {
+ dev_err(mmc_dev(host->mmc), "phy_init: Internal clock never stabilized.\n");
+ return -ETIMEDOUT;
+ }
+ usleep_range(900, 1100);
+ }
+ return 0;
+}
+
/*
* eMMC 5.0/5.1 PHY init/re-init.
* eMMC PHY init should be executed after:
@@ -232,6 +250,11 @@ static int xenon_emmc_phy_init(struct sdhci_host *host)
struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
struct xenon_emmc_phy_regs *phy_regs = priv->emmc_phy_regs;
+ int ret = xenon_check_stability_internal_clk(host);
+
+ if (ret)
+ return ret;
+
reg = sdhci_readl(host, phy_regs->timing_adj);
reg |= XENON_PHY_INITIALIZAION;
sdhci_writel(host, reg, phy_regs->timing_adj);
--
2.25.1
