From: Sowjanya Komatineni <skomatineni@nvidia.com>
To: <adrian.hunter@intel.com>, <ulf.hansson@linaro.org>,
<thierry.reding@gmail.com>, <jonathanh@nvidia.com>,
<robh+dt@kernel.org>
Cc: <skomatineni@nvidia.com>, <devicetree@vger.kernel.org>,
<linux-tegra@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-mmc@vger.kernel.org>
Subject: [PATCH v1 6/6] sdhci: tegra: Add missing TMCLK for data timeout
Date: Mon, 3 Aug 2020 12:44:23 -0700 [thread overview]
Message-ID: <1596483863-22153-7-git-send-email-skomatineni@nvidia.com> (raw)
In-Reply-To: <1596483863-22153-1-git-send-email-skomatineni@nvidia.com>
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 fixes it.
Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
---
drivers/mmc/host/sdhci-tegra.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index 31ed321..39e2195 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -140,6 +140,7 @@ struct sdhci_tegra_autocal_offsets {
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;
bool pad_control_available;
@@ -1611,6 +1612,44 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
goto err_power_req;
}
+ /*
+ * Tegra210 has a separate SDMMC_LEGACY_TM clock used for host
+ * 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 SDR104 mode and when not using SDCLK for data timeout.
+ */
+
+ if ((soc_data->nvquirks & NVQUIRK_ENABLE_SDR104) &&
+ (!soc_data->pdata->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)) {
+ 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)) {
rc = PTR_ERR(clk);
@@ -1654,6 +1693,7 @@ 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);
@@ -1671,6 +1711,7 @@ 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);
--
2.7.4
next prev parent reply other threads:[~2020-08-03 19:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-03 19:44 [PATCH v1 0/6] Fix timeout clock used by hardware data timeout Sowjanya Komatineni
2020-08-03 19:44 ` [PATCH v1 1/6] sdhci: tegra: Remove SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK for Tegra210 Sowjanya Komatineni
2020-08-03 19:44 ` [PATCH v1 2/6] sdhci: tegra: Remove SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK for Tegra186 Sowjanya Komatineni
2020-08-03 19:44 ` [PATCH v1 3/6] arm64: tegra: Add missing timeout clock to Tegra210 SDMMC Sowjanya Komatineni
2020-08-03 19:44 ` [PATCH v1 4/6] arm64: tegra: Add missing timeout clock to Tegra186 SDMMC nodes Sowjanya Komatineni
2020-08-03 19:44 ` [PATCH v1 5/6] arm64: tegra: Add missing timeout clock to Tegra194 " Sowjanya Komatineni
2020-08-03 19:44 ` Sowjanya Komatineni [this message]
2020-08-04 2:26 ` [PATCH v1 6/6] sdhci: tegra: Add missing TMCLK for data timeout kernel test robot
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