mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

PATCH New Gregory CLEMENT 4 participants 8 messages Sep 28, 2017 – Sep 30, 2017

Subsystems (5)

Stable branch Device tree bindings MMC, SD and SDIO Secure digital host controller interface (SDHCI) driver +1 more subsystems

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Gregory CLEMENT

author

2017-09-28 15:05 UTC #0 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock is optional because not all the SoCs need them but at least for Armada 7K/8K it is actually mandatory.

The binding documentation is updating accordingly.

Without this patch the kernel hand during boot if the mvpp2.2 network driver was not present in the kernel. Indeed the clock needed by the xenon controller was set by the network driver.

Fixes 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core

functionality)"

CC Stable <[email protected]>

Signed-off-by Gregory CLEMENT <[email protected]>

---
Hi Ulf and Adrian,

This patch should be merged in 4.14-rc, as it fixes real issues.

This patch maye looks like just as a nice clean-up but it is not. On the earlier version of the series adding the support for the xenon controller there was already this axi bus clock. But at this moment the documentation for the clock on the Armada 7K/8K was missing and there was no driver for it, so we just use the clock set by the bootloader and never change them that's why it worked without any visible problem.

Then as explained in the commit log the network driver enabled the clock for us, and it happened that it was setup before the xenon driver. It is only thanks the new information we received on the clocks of the Sov and with more exhaustive testes that we found this issue and the fix for it.

Thanks,

Gregory

 .../bindings/mmc/marvell,xenon-sdhci.txt           | 12 ++++++-----
 drivers/mmc/host/sdhci-xenon.c                     | 25 +++++++++++++++++++---
 drivers/mmc/host/sdhci-xenon.h                     |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +7 -5

index b878a1e305af..6f3db1f809ab 100644
@@ -16,11 +16,13 @@ Required Properties:
 
 - clocks:
   Array of clocks required for SDHC.
-  Require at least input clock for Xenon IP core.
+  Require at least input clock for Xenon IP core. For Armada AP806 and
+  CP110, the AXI clock is also mandatory.
 
 - clock-names:
   Array of names corresponding to clocks property.
   The input clock for Xenon IP core should be named as "core".
+  The input clock for the AXI bus must be named as "axi".
 
 - reg:
   * For "marvell,armada-3700-sdhci", two register areas.

@@ -106,8 +108,8 @@ Example:
 		compatible = "marvell,armada-ap806-sdhci";
 		reg = <0xaa0000 0x1000>;
 		interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
-		clocks = <&emmc_clk>;
-		clock-names = "core";
+		clocks = <&emmc_clk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-phy-slow-mode;
 		marvell,xenon-tun-count = <11>;

@@ -126,8 +128,8 @@ Example:
 		interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
 		vqmmc-supply = <&sd_vqmmc_regulator>;
 		vmmc-supply = <&sd_vmmc_regulator>;
-		clocks = <&sdclk>;
-		clock-names = "core";
+		clocks = <&sdclk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-tun-count = <9>;
 	};

drivers/mmc/host/sdhci-xenon.c +22 -3

index 2eec2e652c53..845575593b59 100644
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_host *host;
+	struct xenon_priv *priv;
 	int err;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,

@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
 		return PTR_ERR(host);
 
 	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
 
 	/*
 	 * Link Xenon specific mmc_host_ops function,

@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
+		err = PTR_ERR(priv->axi_clk);
+		dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);
+		priv->axi_clk = NULL;
+	} else {
+		err = clk_prepare_enable(priv->axi_clk);
+		if (err)
+			goto err_clk;
+	}
+
 	err = mmc_of_parse(host->mmc);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	sdhci_get_of_property(pdev);

@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
 	/* Xenon specific dt parse */
 	err = xenon_probe_dt(pdev);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	err = xenon_sdhc_prepare(host);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);

@@ -527,6 +540,9 @@ static int xenon_probe(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	xenon_sdhc_unprepare(host);
+err_clk_axi:
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);
 err_clk:
 	clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:

@@ -538,6 +554,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

@@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
 	sdhci_remove_host(host, 0);
 
 	xenon_sdhc_unprepare(host);
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);
 
 	clk_disable_unprepare(pltfm_host->clk);

drivers/mmc/host/sdhci-xenon.h +1 -0

index 2bc0510c0769..9994995c7c56 100644
@@ -83,6 +83,7 @@ struct xenon_priv {
 	unsigned char	bus_width;
 	unsigned char	timing;
 	unsigned int	clock;
+	struct clk      *axi_clk;
 
 	int		phy_type;
 	/*

Signature · 1 line

2.14.1

Gregory CLEMENT

author

2017-09-28 15:57 UTC #1 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

Hi,

Quoted 21 lines · Gregory CLEMENT

drivers/mmc/host/sdhci-xenon.c +2 -0

index 2eec2e652c53..845575593b59 100644
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_host *host;
+	struct xenon_priv *priv;
 	int err;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,

@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
 		return PTR_ERR(host);
 
 	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
 
 	/*
 	 * Link Xenon specific mmc_host_ops function,

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 499

Quoted 7 lines

drivers/mmc/host/sdhci-xenon.c +4 -0

@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
+		err = PTR_ERR(priv->axi_clk);
+		dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);

I should manage the -EPROBE_DEFER case here. So a v2 of this patch is coming soon.

Sorry to not have seen this before sending the patch.

Gregory

Quoted 70 lines

drivers/mmc/host/sdhci-xenon.c +16 -3

+		priv->axi_clk = NULL;
+	} else {
+		err = clk_prepare_enable(priv->axi_clk);
+		if (err)
+			goto err_clk;
+	}
+
 	err = mmc_of_parse(host->mmc);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	sdhci_get_of_property(pdev);

@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
 	/* Xenon specific dt parse */
 	err = xenon_probe_dt(pdev);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	err = xenon_sdhc_prepare(host);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);

@@ -527,6 +540,9 @@ static int xenon_probe(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	xenon_sdhc_unprepare(host);
+err_clk_axi:
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);
 err_clk:
 	clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:

@@ -538,6 +554,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

@@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
 	sdhci_remove_host(host, 0);
 
 	xenon_sdhc_unprepare(host);
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);
 
 	clk_disable_unprepare(pltfm_host->clk);

drivers/mmc/host/sdhci-xenon.h +1 -0

index 2bc0510c0769..9994995c7c56 100644
@@ -83,6 +83,7 @@ struct xenon_priv {
 	unsigned char	bus_width;
 	unsigned char	timing;
 	unsigned int	clock;
+	struct clk      *axi_clk;
 
 	int		phy_type;
 	/*

Signature · 1 line

2.14.1

Signature · 4 lines

Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Jisheng Zhang

2017-09-29 02:39 UTC #2 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

In reply to Gregory CLEMENT

+ DT maintainers

Quoted 49 lines · On Thu, 28 Sep 2017 17:05:20 +0200 Gregory CLEMENT wrote:

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock is optional because not all the SoCs need them but at least for Armada 7K/8K it is actually mandatory.
The binding documentation is updating accordingly.
Without this patch the kernel hand during boot if the mvpp2.2 network driver was not present in the kernel. Indeed the clock needed by the xenon controller was set by the network driver.
Fixes 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
functionality)"
CC Stable <[email protected]>
Signed-off-by Gregory CLEMENT <[email protected]>
---
Hi Ulf and Adrian,
This patch should be merged in 4.14-rc, as it fixes real issues.
This patch maye looks like just as a nice clean-up but it is not. On the earlier version of the series adding the support for the xenon controller there was already this axi bus clock. But at this moment the documentation for the clock on the Armada 7K/8K was missing and there was no driver for it, so we just use the clock set by the bootloader and never change them that's why it worked without any visible problem.
Then as explained in the commit log the network driver enabled the clock for us, and it happened that it was setup before the xenon driver. It is only thanks the new information we received on the clocks of the Sov and with more exhaustive testes that we found this issue and the fix for it.
Thanks,
Gregory
 .../bindings/mmc/marvell,xenon-sdhci.txt           | 12 ++++++-----
 drivers/mmc/host/sdhci-xenon.c                     | 25 +++++++++++++++++++---
 drivers/mmc/host/sdhci-xenon.h                     |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)
Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +0 -0
index b878a1e305af..6f3db1f809ab 100644
@@ -16,11 +16,13 @@ Required Properties:
 

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt Required Properties: · line 25

Quoted 10 lines

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +3 -1

 - clocks:
   Array of clocks required for SDHC.
-  Require at least input clock for Xenon IP core.
+  Require at least input clock for Xenon IP core. For Armada AP806 and
+  CP110, the AXI clock is also mandatory.
 
 - clock-names:
   Array of names corresponding to clocks property.
   The input clock for Xenon IP core should be named as "core".
+  The input clock for the AXI bus must be named as "axi".

Is "bus" more suitable?

Quoted 46 lines

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +4 -4

 - reg:
   * For "marvell,armada-3700-sdhci", two register areas.

@@ -106,8 +108,8 @@ Example:
 		compatible = "marvell,armada-ap806-sdhci";
 		reg = <0xaa0000 0x1000>;
 		interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
-		clocks = <&emmc_clk>;
-		clock-names = "core";
+		clocks = <&emmc_clk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-phy-slow-mode;
 		marvell,xenon-tun-count = <11>;

@@ -126,8 +128,8 @@ Example:
 		interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
 		vqmmc-supply = <&sd_vqmmc_regulator>;
 		vmmc-supply = <&sd_vmmc_regulator>;
-		clocks = <&sdclk>;
-		clock-names = "core";
+		clocks = <&sdclk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-tun-count = <9>;
 	};

drivers/mmc/host/sdhci-xenon.c +2 -0

index 2eec2e652c53..845575593b59 100644
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_host *host;
+	struct xenon_priv *priv;
 	int err;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,

@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
 		return PTR_ERR(host);
 
 	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
 
 	/*
 	 * Link Xenon specific mmc_host_ops function,

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 499

Quoted 7 lines

drivers/mmc/host/sdhci-xenon.c +4 -0

@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
+		err = PTR_ERR(priv->axi_clk);
+		dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);

Since the bus clock is optional, can we remove this err msg?

Quoted 29 lines

drivers/mmc/host/sdhci-xenon.c +10 -3

+		priv->axi_clk = NULL;
+	} else {
+		err = clk_prepare_enable(priv->axi_clk);
+		if (err)
+			goto err_clk;
+	}
+
 	err = mmc_of_parse(host->mmc);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	sdhci_get_of_property(pdev);

@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
 	/* Xenon specific dt parse */
 	err = xenon_probe_dt(pdev);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	err = xenon_sdhc_prepare(host);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 544

Quoted 5 lines

drivers/mmc/host/sdhci-xenon.c +2 -0

@@ -527,6 +540,9 @@ static int xenon_probe(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	xenon_sdhc_unprepare(host);
+err_clk_axi:
+	if (priv->axi_clk)

clk_disable_unprepare() will do the check. So this check could be removed to simplify the err path

Quoted 13 lines

drivers/mmc/host/sdhci-xenon.c +2 -0

+		clk_disable_unprepare(priv->axi_clk);
 err_clk:
 	clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:

@@ -538,6 +554,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

drivers/mmc/host/sdhci-xenon.c static int xenon_remove(struct platform_device *pdev) · line 567

Quoted 5 lines

drivers/mmc/host/sdhci-xenon.c +2 -0

@@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
 	sdhci_remove_host(host, 0);
 
 	xenon_sdhc_unprepare(host);
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);

ditto

Quoted 15 lines

drivers/mmc/host/sdhci-xenon.c +0 -0

 	clk_disable_unprepare(pltfm_host->clk);

drivers/mmc/host/sdhci-xenon.h +1 -0

index 2bc0510c0769..9994995c7c56 100644
@@ -83,6 +83,7 @@ struct xenon_priv {
 	unsigned char	bus_width;
 	unsigned char	timing;
 	unsigned int	clock;
+	struct clk      *axi_clk;
 
 	int		phy_type;
 	/*

Gregory CLEMENT

author

2017-09-29 09:13 UTC #3 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

Hi Jisheng,

Quoted 59 lines · Jisheng Zhang

+ DT maintainers
Quoted 55 lines · On Thu, 28 Sep 2017 17:05:20 +0200 Gregory CLEMENT wrote:
On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock is optional because not all the SoCs need them but at least for Armada 7K/8K it is actually mandatory.
The binding documentation is updating accordingly.
Without this patch the kernel hand during boot if the mvpp2.2 network driver was not present in the kernel. Indeed the clock needed by the xenon controller was set by the network driver.
Fixes 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
functionality)"
CC Stable <[email protected]>
Signed-off-by Gregory CLEMENT <[email protected]>
---
Hi Ulf and Adrian,
This patch should be merged in 4.14-rc, as it fixes real issues.
This patch maye looks like just as a nice clean-up but it is not. On the earlier version of the series adding the support for the xenon controller there was already this axi bus clock. But at this moment the documentation for the clock on the Armada 7K/8K was missing and there was no driver for it, so we just use the clock set by the bootloader and never change them that's why it worked without any visible problem.
Then as explained in the commit log the network driver enabled the clock for us, and it happened that it was setup before the xenon driver. It is only thanks the new information we received on the clocks of the Sov and with more exhaustive testes that we found this issue and the fix for it.
Thanks,
Gregory
 .../bindings/mmc/marvell,xenon-sdhci.txt           | 12 ++++++-----
 drivers/mmc/host/sdhci-xenon.c                     | 25 +++++++++++++++++++---
 drivers/mmc/host/sdhci-xenon.h                     |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)
Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +2 -1
index b878a1e305af..6f3db1f809ab 100644
@@ -16,11 +16,13 @@ Required Properties:
 
 - clocks:
   Array of clocks required for SDHC.
-  Require at least input clock for Xenon IP core.
+  Require at least input clock for Xenon IP core. For Armada AP806 and
+  CP110, the AXI clock is also mandatory.
 

Quoted 6 lines

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt Required Properties: · line 25
Quoted 4 lines
Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +1 -0
 - clock-names:
   Array of names corresponding to clocks property.
   The input clock for Xenon IP core should be named as "core".
+  The input clock for the AXI bus must be named as "axi".
Is "bus" more suitable?

I find bus too vague.

Quoted 50 lines

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +4 -4

 - reg:
   * For "marvell,armada-3700-sdhci", two register areas.

@@ -106,8 +108,8 @@ Example:
 		compatible = "marvell,armada-ap806-sdhci";
 		reg = <0xaa0000 0x1000>;
 		interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
-		clocks = <&emmc_clk>;
-		clock-names = "core";
+		clocks = <&emmc_clk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-phy-slow-mode;
 		marvell,xenon-tun-count = <11>;

@@ -126,8 +128,8 @@ Example:
 		interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
 		vqmmc-supply = <&sd_vqmmc_regulator>;
 		vmmc-supply = <&sd_vmmc_regulator>;
-		clocks = <&sdclk>;
-		clock-names = "core";
+		clocks = <&sdclk>,<&axi_clk>;
+		clock-names = "core","axi";
 		bus-width = <4>;
 		marvell,xenon-tun-count = <9>;
 	};

drivers/mmc/host/sdhci-xenon.c +2 -0

index 2eec2e652c53..845575593b59 100644
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_host *host;
+	struct xenon_priv *priv;
 	int err;
 
 	host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,

@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
 		return PTR_ERR(host);
 
 	pltfm_host = sdhci_priv(host);
+	priv = sdhci_pltfm_priv(pltfm_host);
 
 	/*
 	 * Link Xenon specific mmc_host_ops function,

@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;

Quoted 6 lines

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 499
Quoted 4 lines
drivers/mmc/host/sdhci-xenon.c +4 -0
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
+		err = PTR_ERR(priv->axi_clk);
+		dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);
Since the bus clock is optional, can we remove this err msg?

I will change it in dev_info.

Quoted 27 lines

drivers/mmc/host/sdhci-xenon.c +10 -3

+		priv->axi_clk = NULL;
+	} else {
+		err = clk_prepare_enable(priv->axi_clk);
+		if (err)
+			goto err_clk;
+	}
+
 	err = mmc_of_parse(host->mmc);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	sdhci_get_of_property(pdev);

@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
 	/* Xenon specific dt parse */
 	err = xenon_probe_dt(pdev);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;
 
 	err = xenon_sdhc_prepare(host);
 	if (err)
-		goto err_clk;
+		goto err_clk_axi;

Quoted 11 lines

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 544
Quoted 8 lines
drivers/mmc/host/sdhci-xenon.c +2 -0
 	pm_runtime_get_noresume(&pdev->dev);
 	pm_runtime_set_active(&pdev->dev);
@@ -527,6 +540,9 @@ static int xenon_probe(struct platform_device *pdev)
 	pm_runtime_disable(&pdev->dev);
 	pm_runtime_put_noidle(&pdev->dev);
 	xenon_sdhc_unprepare(host);
+err_clk_axi:
+	if (priv->axi_clk)
clk_disable_unprepare() will do the check. So this check could be removed to simplify the err path

Right I removed it

Quoted 16 lines

drivers/mmc/host/sdhci-xenon.c +2 -0

+		clk_disable_unprepare(priv->axi_clk);
 err_clk:
 	clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:

@@ -538,6 +554,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
 	struct sdhci_host *host = platform_get_drvdata(pdev);
 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
 	pm_runtime_get_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);

@@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
 	sdhci_remove_host(host, 0);

Quoted 5 lines

drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 545
Quoted 3 lines
drivers/mmc/host/sdhci-xenon.c +2 -0
 	xenon_sdhc_unprepare(host);
+	if (priv->axi_clk)
+		clk_disable_unprepare(priv->axi_clk);
ditto

Thanks,

Gregory

Signature · 4 lines

Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Thomas Petazzoni

2017-09-29 09:15 UTC #4 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

Hello,

Quoted 8 lines · Gregory CLEMENT

Quoted 6 lines
Quoted 4 lines
- clock-names:
Array of names corresponding to clocks property. The input clock for Xenon IP core should be named as "core".
+ The input clock for the AXI bus must be named as "axi".
Is "bus" more suitable?
I find bus too vague.

Actually no, I believe "bus" is more common. Indeed, you could have the same IP, attached to a different interconnect I guess.

Quoted 8 lines

Quoted 8 lines
drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 497
Quoted 8 lines
drivers/mmc/host/sdhci-xenon.c +2 -0
 	/*
 	 * Link Xenon specific mmc_host_ops function,
@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {

-EPROBE_DEFER handling ?

Quoted 6 lines

Quoted 4 lines
drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 499
Quoted 2 lines
drivers/mmc/host/sdhci-xenon.c +2 -0
+		err = PTR_ERR(priv->axi_clk);
+		dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);  
Since the bus clock is optional, can we remove this err msg?
I will change it in dev_info.

This clock is optional (in order to keep DT backward compatibility), so there shouldn't be any error message, be it dev_err() or dev_info().

Best regards,

Thomas

Signature · 3 lines

Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

Gregory CLEMENT

author

2017-09-29 09:22 UTC #5 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

Hi Thomas,

Quoted 22 lines · Thomas Petazzoni

Hello,
Quoted 8 lines · Gregory CLEMENT
Quoted 6 lines
Quoted 4 lines
- clock-names:
Array of names corresponding to clocks property. The input clock for Xenon IP core should be named as "core".
+ The input clock for the AXI bus must be named as "axi".
Is "bus" more suitable?
I find bus too vague.
Actually no, I believe "bus" is more common. Indeed, you could have the same IP, attached to a different interconnect I guess.
Quoted 6 lines
Quoted 6 lines
Quoted 6 lines
drivers/mmc/host/sdhci-xenon.c +0 -0
 	/*
 	 * Link Xenon specific mmc_host_ops function,
@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
 	if (err)
 		goto free_pltfm;
 

Quoted 4 lines

Quoted 2 lines
Quoted 2 lines
drivers/mmc/host/sdhci-xenon.c static int xenon_probe(struct platform_device *pdev) · line 497
Quoted 2 lines
drivers/mmc/host/sdhci-xenon.c +2 -0
+	priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+	if (IS_ERR(priv->axi_clk)) {
-EPROBE_DEFER handling ?

See
http://lists.infradead.org/pipermail/linux-arm-kernel/2017-September/533510.html

Gregory

Signature · 4 lines

Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com

Ziji Hu

2017-09-30 02:47 UTC #6 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

In reply to Gregory CLEMENT

Hi Gregory,

2017-09-28 23:05 GMT+08:00 Gregory CLEMENT <[email protected]>:

Quoted 27 lines

On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock is optional because not all the SoCs need them but at least for Armada 7K/8K it is actually mandatory.
The binding documentation is updating accordingly.
Without this patch the kernel hand during boot if the mvpp2.2 network driver was not present in the kernel. Indeed the clock needed by the xenon controller was set by the network driver.
Fixes 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
functionality)"
CC Stable <[email protected]>
Signed-off-by Gregory CLEMENT <[email protected]>
---
Hi Ulf and Adrian,
This patch should be merged in 4.14-rc, as it fixes real issues.
This patch maye looks like just as a nice clean-up but it is not. On the earlier version of the series adding the support for the xenon controller there was already this axi bus clock. But at this moment the documentation for the clock on the Armada 7K/8K was missing and there was no driver for it, so we just use the clock set by the bootloader and never change them that's why it worked without any visible problem.

Quoted 5 lines

Then as explained in the commit log the network driver enabled the clock for us, and it happened that it was setup before the xenon driver. It is only thanks the new information we received on the clocks of the Sov and with more exhaustive testes that we found this issue and the fix for it.

I know very little about clk in Linux.
But I just happened to review this very issue before I left Marvell. I had some concerns about this patch at that time. Please check the following.

1. If that network device is used again, so that clock will be setup *twice* since there are two duplicated clock setup in that network driver
and Xenon driver. Right?
2. If that network device is used again and Xenon later exists and
shutdown the clock,
will that network device be corrupted?
3. In my very own opinion, such a shared AXI bus clock might be
controlled in u-boot or
a "SoC-level" init routine.

Please correct me if there is any misunderstanding.

Thank you.

Best regards,
Hu Ziji

Quoted 154 lines

Thanks,

Gregory

 .../bindings/mmc/marvell,xenon-sdhci.txt           | 12 ++++++-----
 drivers/mmc/host/sdhci-xenon.c                     | 25 +++++++++++++++++++---
 drivers/mmc/host/sdhci-xenon.h                     |  1 +
 3 files changed, 30 insertions(+), 8 deletions(-)

Documentation/devicetree/bindings/mmc/marvell,xenon-sdhci.txt +7 -5

index b878a1e305af..6f3db1f809ab 100644
@@ -16,11 +16,13 @@ Required Properties:
 
 - clocks:
   Array of clocks required for SDHC.
-  Require at least input clock for Xenon IP core.
+  Require at least input clock for Xenon IP core. For Armada AP806 and
+  CP110, the AXI clock is also mandatory.
 
 - clock-names:
   Array of names corresponding to clocks property.
   The input clock for Xenon IP core should be named as "core".
+  The input clock for the AXI bus must be named as "axi".
 
 - reg:
   * For "marvell,armada-3700-sdhci", two register areas.

@@ -106,8 +108,8 @@ Example:
                compatible = "marvell,armada-ap806-sdhci";
                reg = <0xaa0000 0x1000>;
                interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
-               clocks = <&emmc_clk>;
-               clock-names = "core";
+               clocks = <&emmc_clk>,<&axi_clk>;
+               clock-names = "core","axi";
                bus-width = <4>;
                marvell,xenon-phy-slow-mode;
                marvell,xenon-tun-count = <11>;

@@ -126,8 +128,8 @@ Example:
                interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
                vqmmc-supply = <&sd_vqmmc_regulator>;
                vmmc-supply = <&sd_vmmc_regulator>;
-               clocks = <&sdclk>;
-               clock-names = "core";
+               clocks = <&sdclk>,<&axi_clk>;
+               clock-names = "core","axi";
                bus-width = <4>;
                marvell,xenon-tun-count = <9>;
        };

drivers/mmc/host/sdhci-xenon.c +22 -3

index 2eec2e652c53..845575593b59 100644
@@ -466,6 +466,7 @@ static int xenon_probe(struct platform_device *pdev)
 {
        struct sdhci_pltfm_host *pltfm_host;
        struct sdhci_host *host;
+       struct xenon_priv *priv;
        int err;
 
        host = sdhci_pltfm_init(pdev, &sdhci_xenon_pdata,

@@ -474,6 +475,7 @@ static int xenon_probe(struct platform_device *pdev)
                return PTR_ERR(host);
 
        pltfm_host = sdhci_priv(host);
+       priv = sdhci_pltfm_priv(pltfm_host);
 
        /*
         * Link Xenon specific mmc_host_ops function,

@@ -491,9 +493,20 @@ static int xenon_probe(struct platform_device *pdev)
        if (err)
                goto free_pltfm;
 
+       priv->axi_clk = devm_clk_get(&pdev->dev, "axi");
+       if (IS_ERR(priv->axi_clk)) {
+               err = PTR_ERR(priv->axi_clk);
+               dev_err(&pdev->dev, "Failed to setup axi clk: %d\n", err);
+               priv->axi_clk = NULL;
+       } else {
+               err = clk_prepare_enable(priv->axi_clk);
+               if (err)
+                       goto err_clk;
+       }
+
        err = mmc_of_parse(host->mmc);
        if (err)
-               goto err_clk;
+               goto err_clk_axi;
 
        sdhci_get_of_property(pdev);

@@ -502,11 +515,11 @@ static int xenon_probe(struct platform_device *pdev)
        /* Xenon specific dt parse */
        err = xenon_probe_dt(pdev);
        if (err)
-               goto err_clk;
+               goto err_clk_axi;
 
        err = xenon_sdhc_prepare(host);
        if (err)
-               goto err_clk;
+               goto err_clk_axi;
 
        pm_runtime_get_noresume(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);

@@ -527,6 +540,9 @@ static int xenon_probe(struct platform_device *pdev)
        pm_runtime_disable(&pdev->dev);
        pm_runtime_put_noidle(&pdev->dev);
        xenon_sdhc_unprepare(host);
+err_clk_axi:
+       if (priv->axi_clk)
+               clk_disable_unprepare(priv->axi_clk);
 err_clk:
        clk_disable_unprepare(pltfm_host->clk);
 free_pltfm:

@@ -538,6 +554,7 @@ static int xenon_remove(struct platform_device *pdev)
 {
        struct sdhci_host *host = platform_get_drvdata(pdev);
        struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+       struct xenon_priv *priv = sdhci_pltfm_priv(pltfm_host);
 
        pm_runtime_get_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

@@ -546,6 +563,8 @@ static int xenon_remove(struct platform_device *pdev)
        sdhci_remove_host(host, 0);
 
        xenon_sdhc_unprepare(host);
+       if (priv->axi_clk)
+               clk_disable_unprepare(priv->axi_clk);
 
        clk_disable_unprepare(pltfm_host->clk);

drivers/mmc/host/sdhci-xenon.h +1 -1

index 2bc0510c0769..9994995c7c56 100644
@@ -83,6 +83,7 @@ struct xenon_priv {
        unsigned char   bus_width;
        unsigned char   timing;
        unsigned int    clock;
+       struct clk      *axi_clk;
 
        int             phy_type;
        /*
--

2.14.1

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Jisheng Zhang

2017-09-30 02:56 UTC #7 lore raw

PATCH 1/1 mmc: sdhci-xenon: Fix clock resource by adding an optional bus clock

Hi Ziji,

Quoted 36 lines · On Sat, 30 Sep 2017 10:47:39 +0800 Ziji Hu wrote:

Hi Gregory,
2017-09-28 23:05 GMT+08:00 Gregory CLEMENT <[email protected]>:
Quoted 27 lines
On Armada 7K/8K we need to explicitly enable the bus clock. The bus clock is optional because not all the SoCs need them but at least for Armada 7K/8K it is actually mandatory.
The binding documentation is updating accordingly.
Without this patch the kernel hand during boot if the mvpp2.2 network driver was not present in the kernel. Indeed the clock needed by the xenon controller was set by the network driver.
Fixes 3a3748dba881 ("mmc: sdhci-xenon: Add Marvell Xenon SDHC core
functionality)"
CC Stable <[email protected]>
Signed-off-by Gregory CLEMENT <[email protected]>
---
Hi Ulf and Adrian,
This patch should be merged in 4.14-rc, as it fixes real issues.
This patch maye looks like just as a nice clean-up but it is not. On the earlier version of the series adding the support for the xenon controller there was already this axi bus clock. But at this moment the documentation for the clock on the Armada 7K/8K was missing and there was no driver for it, so we just use the clock set by the bootloader and never change them that's why it worked without any visible problem.
Quoted 5 lines
Then as explained in the commit log the network driver enabled the clock for us, and it happened that it was setup before the xenon driver. It is only thanks the new information we received on the clocks of the Sov and with more exhaustive testes that we found this issue and the fix for it.

Quoted 8 lines

I know very little about clk in Linux.
But I just happened to review this very issue before I left Marvell. I had some concerns about this patch at that time. Please check the following.
1. If that network device is used again, so that clock will be setup *twice* since there are two duplicated clock setup in that network driver
and Xenon driver. Right?

The first "setup" will be executed, the second one just increase the enable and prepare count.

Quoted 3 lines

2. If that network device is used again and Xenon later exists and
shutdown the clock,
will that network device be corrupted?

No. The enable and prepare count is reduced to 1, nothing else could happen. The clock won't be shutdown until there's no users.

Quoted 3 lines

3. In my very own opinion, such a shared AXI bus clock might be
controlled in u-boot or
a "SoC-level" init routine.

IMHO, it's the driver's responsibility to manage its own clocks.

Thanks