commit b5a84ecf025a ("mmc: tegra: Add Tegra210 support")
Tegra210 and later has a separate sdmmc_legacy_tm (TMCLK) used by Tegra SDMMC hawdware for data timeout to achive better timeout than using SDCLK and using TMCLK is recommended.
USE_TMCLK_FOR_DATA_TIMEOUT bit in Tegra SDMMC register SDHCI_TEGRA_VENDOR_SYS_SW_CTRL can be used to choose either TMCLK or SDCLK for data timeout.
Default USE_TMCLK_FOR_DATA_TIMEOUT bit is set to 1 and TMCLK is used for data timeout by Tegra SDMMC hardware and having TMCLK not enabled is not recommended.
So, this patch adds quirk NVQUIRK_HAS_TMCLK for SoC having separate timeout clock and keeps TMCLK enabled all the time.
Fixes: b5a84ecf025a ("mmc: tegra: Add Tegra210 support") Cc: stable stable@vger.kernel.org # 4.19 Tested-by: Jon Hunter jonathanh@nvidia.com Reviewed-by: Jon Hunter jonathanh@nvidia.com Acked-by: Adrian Hunter adrian.hunter@intel.com Signed-off-by: Sowjanya Komatineni skomatineni@nvidia.com --- drivers/mmc/host/sdhci-tegra.c | 48 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+)
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c index 5a7c032..ff3340c 100644 --- a/drivers/mmc/host/sdhci-tegra.c +++ b/drivers/mmc/host/sdhci-tegra.c @@ -56,6 +56,12 @@ #define NVQUIRK_ENABLE_DDR50 BIT(5) #define NVQUIRK_HAS_PADCALIB BIT(6)
+/* + * NVQUIRK_HAS_TMCLK is for SoC's having separate timeout clock for Tegra + * SDMMC hardware data timeout. + */ +#define NVQUIRK_HAS_TMCLK BIT(10) + struct sdhci_tegra_soc_data { const struct sdhci_pltfm_data *pdata; u32 nvquirks; @@ -64,6 +70,7 @@ struct sdhci_tegra_soc_data { struct sdhci_tegra { const struct sdhci_tegra_soc_data *soc_data; struct gpio_desc *power_gpio; + struct clk *tmclk; bool ddr_signaling; bool pad_calib_required;
@@ -433,6 +440,7 @@ static const struct sdhci_pltfm_data sdhci_tegra210_pdata = {
static const struct sdhci_tegra_soc_data soc_data_tegra210 = { .pdata = &sdhci_tegra210_pdata, + .nvquirks = NVQUIRK_HAS_TMCLK, };
static const struct sdhci_pltfm_data sdhci_tegra186_pdata = { @@ -455,6 +463,7 @@ static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
static const struct sdhci_tegra_soc_data soc_data_tegra186 = { .pdata = &sdhci_tegra186_pdata, + .nvquirks = NVQUIRK_HAS_TMCLK, };
static const struct of_device_id sdhci_tegra_dt_match[] = { @@ -510,6 +519,43 @@ static int sdhci_tegra_probe(struct platform_device *pdev) goto err_power_req; }
+ /* + * Some Tegra SoC's has a separate SDMMC_LEGACY_TM clock used for + * host data timeout clock and SW can choose TMCLK or SDCLK for + * hardware data timeout through the bit USE_TMCLK_FOR_DATA_TIMEOUT + * of the register SDHCI_TEGRA_VENDOR_SYS_SW_CTRL. + * + * USE_TMCLK_FOR_DATA_TIMEOUT bit default is set to 1 and SDMMC uses + * 12Mhz TMCLK which is advertised in host capability register. + * With TMCLK of 12Mhz provides maximum data timeout period that can + * be achieved is 11s better than using SDCLK for data timeout. + * + * So, TMCLK is set to 12Mhz and kept enabled all the time on SoC's + * supporting separate TMCLK. + */ + + if (soc_data->nvquirks & NVQUIRK_HAS_TMCLK) { + clk = devm_clk_get(&pdev->dev, "tmclk"); + if (IS_ERR(clk)) { + rc = PTR_ERR(clk); + if (rc == -EPROBE_DEFER) + goto err_power_req; + + dev_warn(&pdev->dev, "failed to get tmclk: %d\n", rc); + clk = NULL; + } + + clk_set_rate(clk, 12000000); + rc = clk_prepare_enable(clk); + if (rc) { + dev_err(&pdev->dev, + "failed to enable tmclk: %d\n", rc); + goto err_power_req; + } + + tegra_host->tmclk = clk; + } + clk = devm_clk_get(mmc_dev(host->mmc), NULL); if (IS_ERR(clk)) { dev_err(mmc_dev(host->mmc), "clk err\n"); @@ -550,6 +596,7 @@ static int sdhci_tegra_probe(struct platform_device *pdev) err_rst_get: clk_disable_unprepare(pltfm_host->clk); err_clk_get: + clk_disable_unprepare(tegra_host->tmclk); err_power_req: err_parse_dt: sdhci_pltfm_free(pdev); @@ -567,6 +614,7 @@ static int sdhci_tegra_remove(struct platform_device *pdev) reset_control_assert(tegra_host->rst); usleep_range(2000, 4000); clk_disable_unprepare(pltfm_host->clk); + clk_disable_unprepare(tegra_host->tmclk);
sdhci_pltfm_free(pdev);