mmc: sdhci: reset sdclk before setting high speed enable

[firefly-linux-kernel-4.4.55.git] / drivers / mmc / host / sdhci.c

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 8072e16d6d46743bedcd97a5567b13ec2ecef7eb..409cde5970ae2dcf8573409e8710f404b11b1fa6 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1243,13 +1243,12 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
        else
                ctrl &= ~SDHCI_CTRL_HISPD;
 
-       sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
-
        if (host->version >= SDHCI_SPEC_300) {
                u16 ctrl_2;
 
                ctrl_2 = sdhci_readw(host, SDHCI_HOST_CONTROL2);
                if (!(ctrl_2 & SDHCI_CTRL_PRESET_VAL_ENABLE)) {
+                       sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
                        /*
                         * We only need to set Driver Strength if the
                         * preset value enable is not set.
@@ -1261,8 +1260,30 @@ static void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
                                ctrl_2 |= SDHCI_CTRL_DRV_TYPE_C;
 
                        sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
+               } else {
+                       /*
+                        * According to SDHC Spec v3.00, if the Preset Value
+                        * Enable in the Host Control 2 register is set, we
+                        * need to reset SD Clock Enable before changing High
+                        * Speed Enable to avoid generating clock gliches.
+                        */
+                       u16 clk;
+                       unsigned int clock;
+
+                       /* Reset SD Clock Enable */
+                       clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
+                       clk &= ~SDHCI_CLOCK_CARD_EN;
+                       sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
+
+                       sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
+
+                       /* Re-enable SD Clock */
+                       clock = host->clock;
+                       host->clock = 0;
+                       sdhci_set_clock(host, clock);
                }
-       }
+       } else
+               sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
 
        /*
         * Some (ENE) controllers go apeshit on some ios operation,