From: Prathamesh Shete pshete@nvidia.com
commit 4fc7261dbab139d3c64c3b618262504e16cfe7ee upstream.
When CMD13 is sent after switching to HS400ES mode, the bus is operating at either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host controller CAR clock and the interface clock are rate matched.
Signed-off-by: Prathamesh Shete pshete@nvidia.com Acked-by: Adrian Hunter adrian.hunter@intel.com Fixes: dfc9700cef77 ("mmc: tegra: Implement HS400 enhanced strobe") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20211214113653.4631-1-pshete@nvidia.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mmc/host/sdhci-tegra.c | 43 ++++++++++++++++++++++++----------------- 1 file changed, 26 insertions(+), 17 deletions(-)
--- a/drivers/mmc/host/sdhci-tegra.c +++ b/drivers/mmc/host/sdhci-tegra.c @@ -354,23 +354,6 @@ static void tegra_sdhci_set_tap(struct s } }
-static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, - struct mmc_ios *ios) -{ - struct sdhci_host *host = mmc_priv(mmc); - u32 val; - - val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); - - if (ios->enhanced_strobe) - val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; - else - val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; - - sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); - -} - static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); @@ -791,6 +774,32 @@ static void tegra_sdhci_set_clock(struct } }
+static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, + struct mmc_ios *ios) +{ + struct sdhci_host *host = mmc_priv(mmc); + u32 val; + + val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); + + if (ios->enhanced_strobe) { + val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; + /* + * When CMD13 is sent from mmc_select_hs400es() after + * switching to HS400ES mode, the bus is operating at + * either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. + * To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI + * interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host + * controller CAR clock and the interface clock are rate matched. + */ + tegra_sdhci_set_clock(host, MMC_HS200_MAX_DTR); + } else { + val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; + } + + sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); +} + static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host *host) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);