[PATCH V5 0/2] Re-initialize DLL when MCLK is gated dynamically

[PATCH V5 0/2] Re-initialize DLL when MCLK is gated dynamically

[Veerabhadrarao Badiganti]

On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually, result in data CRC and command CRC/timeout errors.
To fix this issue, the DLL needs to be re-initialized and restored with
its old settings once clocks are ungated. SDHC cotroller on SDM845 SOC
has this limitation.

Changes since V4:
	- Exactly same as V3, posted multiple mails for V4.
	So to avoid confusion updating it as V5.

Changes since V3:
	- Introduced SoC specific dt compatible string for sdhci-msm
	controller
	- Moved the condition which checks whether tuning is needed or
	not, to a common function.

Changes since V2:
	- Removed an unused variable.
	- Renamed the newly introduced flags to be more meaningful.
	- Added new dt compatible string for SDM845 SOC.

Changes since V1:
	- Replaced dt flag with a dt compatible string to
	indicate SHDCI-MSM controller varients which need this fix.
	- Moved the DLL settings restoration logic from request 
	context to platform driver runtime pm context.

Tested on: sdm845
Veerabhadrarao Badiganti (2):
  dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings
  mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

 .../devicetree/bindings/mmc/sdhci-msm.txt          | 21 ++++--
 drivers/mmc/host/sdhci-msm.c                       | 78 +++++++++++++++++++---
 2 files changed, 84 insertions(+), 15 deletions(-)

-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH V5 1/2] dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings

[Veerabhadrarao Badiganti]

Add SoC-specific compatible strings for qcom-sdhci controller.

Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
---
 Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
index 502b3b8..b72871a 100644
--- a/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
+++ b/Documentation/devicetree/bindings/mmc/sdhci-msm.txt
@@ -4,12 +4,25 @@ This file documents differences between the core properties in mmc.txt
 and the properties used by the sdhci-msm driver.
 
 Required properties:
-- compatible: Should contain:
+- compatible: Should contain a SoC-specific string and a IP version string:
+	version strings:
 		"qcom,sdhci-msm-v4" for sdcc versions less than 5.0
-		"qcom,sdhci-msm-v5" for sdcc versions >= 5.0
+		"qcom,sdhci-msm-v5" for sdcc version 5.0
 		For SDCC version 5.0.0, MCI registers are removed from SDCC
 		interface and some registers are moved to HC. New compatible
 		string is added to support this change - "qcom,sdhci-msm-v5".
+	full compatible strings with SoC and version:
+		"qcom,apq8084-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,msm8974-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,msm8916-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,msm8992-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,msm8996-sdhci", "qcom,sdhci-msm-v4"
+		"qcom,sdm845-sdhci", "qcom,sdhci-msm-v5"
+		"qcom,qcs404-sdhci", "qcom,sdhci-msm-v5"
+	NOTE that some old device tree files may be floating around that only
+	have the string "qcom,sdhci-msm-v4" without the SoC compatible string
+	but doing that should be considered a deprecated practice.
+
 - reg: Base address and length of the register in the following order:
 	- Host controller register map (required)
 	- SD Core register map (required)
@@ -29,7 +42,7 @@ Required properties:
 Example:
 
 	sdhc_1: sdhci@f9824900 {
-		compatible = "qcom,sdhci-msm-v4";
+		compatible = "qcom,msm8974-sdhci", "qcom,sdhci-msm-v4";
 		reg = <0xf9824900 0x11c>, <0xf9824000 0x800>;
 		interrupts = <0 123 0>;
 		bus-width = <8>;
@@ -46,7 +59,7 @@ Example:
 	};
 
 	sdhc_2: sdhci@f98a4900 {
-		compatible = "qcom,sdhci-msm-v4";
+		compatible = "qcom,msm8974-sdhci", "qcom,sdhci-msm-v4";
 		reg = <0xf98a4900 0x11c>, <0xf98a4000 0x800>;
 		interrupts = <0 125 0>;
 		bus-width = <4>;
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

[PATCH V5 2/2] mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

[Veerabhadrarao Badiganti]

On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually will result in data CRC, command CRC/timeout errors.
To overcome this h/w limitation, the DLL needs to be re-initialized
and restored with its old settings once clocks are ungated.

Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
---
 drivers/mmc/host/sdhci-msm.c | 78 +++++++++++++++++++++++++++++++++++++-------
 1 file changed, 67 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 3cc8bfe..4cac593 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c
@@ -232,6 +232,7 @@ struct sdhci_msm_variant_ops {
  */
 struct sdhci_msm_variant_info {
 	bool mci_removed;
+	bool restore_dll_config;
 	const struct sdhci_msm_variant_ops *var_ops;
 	const struct sdhci_msm_offset *offset;
 };
@@ -256,6 +257,7 @@ struct sdhci_msm_host {
 	bool pwr_irq_flag;
 	u32 caps_0;
 	bool mci_removed;
+	bool restore_dll_config;
 	const struct sdhci_msm_variant_ops *var_ops;
 	const struct sdhci_msm_offset *offset;
 };
@@ -1025,6 +1027,48 @@ static int sdhci_msm_hs400_dll_calibration(struct sdhci_host *host)
 	return ret;
 }
 
+static bool sdhci_msm_is_tuning_needed(struct sdhci_host *host)
+{
+	struct mmc_ios *ios = &host->mmc->ios;
+
+	/*
+	 * Tuning is required for SDR104, HS200 and HS400 cards and
+	 * if clock frequency is greater than 100MHz in these modes.
+	 */
+	if (host->clock <= CORE_FREQ_100MHZ ||
+	    !(ios->timing == MMC_TIMING_MMC_HS400 ||
+	    ios->timing == MMC_TIMING_MMC_HS200 ||
+	    ios->timing == MMC_TIMING_UHS_SDR104) ||
+	    ios->enhanced_strobe)
+		return false;
+
+	return true;
+}
+
+static int sdhci_msm_restore_sdr_dll_config(struct sdhci_host *host)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	/*
+	 * SDR DLL comes into picture only for timing modes which needs
+	 * tuning.
+	 */
+	if (!sdhci_msm_is_tuning_needed(host))
+		return 0;
+
+	/* Reset the tuning block */
+	ret = msm_init_cm_dll(host);
+	if (ret)
+		return ret;
+
+	/* Restore the tuning block */
+	ret = msm_config_cm_dll_phase(host, msm_host->saved_tuning_phase);
+
+	return ret;
+}
+
 static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -1035,14 +1079,7 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
 
-	/*
-	 * Tuning is required for SDR104, HS200 and HS400 cards and
-	 * if clock frequency is greater than 100MHz in these modes.
-	 */
-	if (host->clock <= CORE_FREQ_100MHZ ||
-	    !(ios.timing == MMC_TIMING_MMC_HS400 ||
-	    ios.timing == MMC_TIMING_MMC_HS200 ||
-	    ios.timing == MMC_TIMING_UHS_SDR104))
+	if (!sdhci_msm_is_tuning_needed(host))
 		return 0;
 
 	/*
@@ -1069,7 +1106,6 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		if (rc)
 			return rc;
 
-		msm_host->saved_tuning_phase = phase;
 		rc = mmc_send_tuning(mmc, opcode, NULL);
 		if (!rc) {
 			/* Tuning is successful at this tuning point */
@@ -1094,6 +1130,7 @@ static int sdhci_msm_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		rc = msm_config_cm_dll_phase(host, phase);
 		if (rc)
 			return rc;
+		msm_host->saved_tuning_phase = phase;
 		dev_dbg(mmc_dev(mmc), "%s: Setting the tuning phase to %d\n",
 			 mmc_hostname(mmc), phase);
 	} else {
@@ -1616,7 +1653,6 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
 };
 
 static const struct sdhci_msm_variant_info sdhci_msm_mci_var = {
-	.mci_removed = false,
 	.var_ops = &mci_var_ops,
 	.offset = &sdhci_msm_mci_offset,
 };
@@ -1627,9 +1663,17 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
 	.offset = &sdhci_msm_v5_offset,
 };
 
+static const struct sdhci_msm_variant_info sdm845_sdhci_var = {
+	.mci_removed = true,
+	.restore_dll_config = true,
+	.var_ops = &v5_var_ops,
+	.offset = &sdhci_msm_v5_offset,
+};
+
 static const struct of_device_id sdhci_msm_dt_match[] = {
 	{.compatible = "qcom,sdhci-msm-v4", .data = &sdhci_msm_mci_var},
 	{.compatible = "qcom,sdhci-msm-v5", .data = &sdhci_msm_v5_var},
+	{.compatible = "qcom,sdm845-sdhci", .data = &sdm845_sdhci_var},
 	{},
 };
 
@@ -1689,6 +1733,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
 	var_info = of_device_get_match_data(&pdev->dev);
 
 	msm_host->mci_removed = var_info->mci_removed;
+	msm_host->restore_dll_config = var_info->restore_dll_config;
 	msm_host->var_ops = var_info->var_ops;
 	msm_host->offset = var_info->offset;
 
@@ -1928,9 +1973,20 @@ static int sdhci_msm_runtime_resume(struct device *dev)
 	struct sdhci_host *host = dev_get_drvdata(dev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
 	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
+	int ret;
 
-	return clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
+	ret = clk_bulk_prepare_enable(ARRAY_SIZE(msm_host->bulk_clks),
 				       msm_host->bulk_clks);
+	if (ret)
+		return ret;
+	/*
+	 * Whenever core-clock is gated dynamically, it's needed to
+	 * restore the SDR DLL settings when the clock is ungated.
+	 */
+	if (msm_host->restore_dll_config && msm_host->clk_rate)
+		return sdhci_msm_restore_sdr_dll_config(host);
+
+	return 0;
 }
 #endif
 
-- 
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project.

Re: [PATCH V5 1/2] dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings

[Rob Herring]

On Mon, 12 Nov 2018 12:22:16 +0530, Veerabhadrarao Badiganti wrote:
> Add SoC-specific compatible strings for qcom-sdhci controller.
> 
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>
> ---
>  Documentation/devicetree/bindings/mmc/sdhci-msm.txt | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 

Reviewed-by: Rob Herring <robh@kernel.org>

Re: [PATCH V5 2/2] mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

[Evan Green]

On Sun, Nov 11, 2018 at 10:53 PM Veerabhadrarao Badiganti
<vbadigan@codeaurora.org> wrote:
>
> On few SDHCI-MSM controllers, the host controller's clock tuning
> circuit may go out of sync if controller clocks are gated which
> eventually will result in data CRC, command CRC/timeout errors.
> To overcome this h/w limitation, the DLL needs to be re-initialized
> and restored with its old settings once clocks are ungated.
>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@codeaurora.org>

Reviewed-by: Evan Green <evgreen@chromium.org>

Re: [PATCH V5 0/2] Re-initialize DLL when MCLK is gated dynamically

[Ulf Hansson]

On 12 November 2018 at 07:52, Veerabhadrarao Badiganti
<vbadigan@codeaurora.org> wrote:
> On few SDHCI-MSM controllers, the host controller's clock tuning
> circuit may go out of sync if controller clocks are gated which
> eventually, result in data CRC and command CRC/timeout errors.
> To fix this issue, the DLL needs to be re-initialized and restored with
> its old settings once clocks are ungated. SDHC cotroller on SDM845 SOC
> has this limitation.
>
> Changes since V4:
>         - Exactly same as V3, posted multiple mails for V4.
>         So to avoid confusion updating it as V5.
>
> Changes since V3:
>         - Introduced SoC specific dt compatible string for sdhci-msm
>         controller
>         - Moved the condition which checks whether tuning is needed or
>         not, to a common function.
>
> Changes since V2:
>         - Removed an unused variable.
>         - Renamed the newly introduced flags to be more meaningful.
>         - Added new dt compatible string for SDM845 SOC.
>
> Changes since V1:
>         - Replaced dt flag with a dt compatible string to
>         indicate SHDCI-MSM controller varients which need this fix.
>         - Moved the DLL settings restoration logic from request
>         context to platform driver runtime pm context.
>
> Tested on: sdm845
> Veerabhadrarao Badiganti (2):
>   dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings
>   mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically
>
>  .../devicetree/bindings/mmc/sdhci-msm.txt          | 21 ++++--
>  drivers/mmc/host/sdhci-msm.c                       | 78 +++++++++++++++++++---
>  2 files changed, 84 insertions(+), 15 deletions(-)

Applied for next, thanks!

Kind regards
Uffe