diff mbox

[v3,3/4] drivers: exynos-srom: Add support for bank configuration

Message ID 048021141f295b0e70c852134d4ac9cc6f7f1da4.1446018918.git.p.fedin@samsung.com (mailing list archive)
State New, archived
Headers show

Commit Message

Pavel Fedin Oct. 28, 2015, 7:57 a.m. UTC
Bindings are based on u-boot implementation, however they are stored in
subnodes, providing support for more than one bank.

Since the driver now does more than suspend-resume support, dependency on
CONFIG_PM is removed.

Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
---
 arch/arm/mach-exynos/Kconfig      |  2 +-
 drivers/soc/samsung/Kconfig       |  2 +-
 drivers/soc/samsung/exynos-srom.c | 42 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 43 insertions(+), 3 deletions(-)

Comments

Krzysztof Kozlowski Oct. 29, 2015, 2:16 a.m. UTC | #1
On 28.10.2015 16:57, Pavel Fedin wrote:
> Bindings are based on u-boot implementation, however they are stored in
> subnodes, providing support for more than one bank.
> 
> Since the driver now does more than suspend-resume support, dependency on
> CONFIG_PM is removed.
> 
> Signed-off-by: Pavel Fedin <p.fedin@samsung.com>
> ---
>  arch/arm/mach-exynos/Kconfig      |  2 +-
>  drivers/soc/samsung/Kconfig       |  2 +-
>  drivers/soc/samsung/exynos-srom.c | 42 ++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 43 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
> index 83c85f5..c22dc42 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -16,7 +16,7 @@ menuconfig ARCH_EXYNOS
>  	select ARM_GIC
>  	select COMMON_CLK_SAMSUNG
>  	select EXYNOS_THERMAL
> -	select EXYNOS_SROM if PM
> +	select EXYNOS_SROM
>  	select HAVE_ARM_SCU if SMP
>  	select HAVE_S3C2410_I2C if I2C
>  	select HAVE_S3C2410_WATCHDOG if WATCHDOG
> diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
> index 2833b5b..ea4bc2a 100644
> --- a/drivers/soc/samsung/Kconfig
> +++ b/drivers/soc/samsung/Kconfig
> @@ -8,6 +8,6 @@ config SOC_SAMSUNG
>  
>  config EXYNOS_SROM
>  	bool
> -	depends on ARM && ARCH_EXYNOS && PM
> +	depends on ARM && ARCH_EXYNOS
>  
>  endmenu
> diff --git a/drivers/soc/samsung/exynos-srom.c b/drivers/soc/samsung/exynos-srom.c
> index 57a232d..6c8c56a 100644
> --- a/drivers/soc/samsung/exynos-srom.c
> +++ b/drivers/soc/samsung/exynos-srom.c
> @@ -67,9 +67,46 @@ static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
>  	return rd;
>  }
>  
> +static int decode_sromc(struct exynos_srom *srom, struct device_node *np)
> +{
> +	u32 bank, width;
> +	u32 timing[7];
> +	u32 bw;
> +
> +	if (of_property_read_u32(np, "bank", &bank))
> +		return -ENXIO;

This is an invalid value in DTB, not missing device or address, so -EINVAL.

> +	if (of_property_read_u32(np, "width", &width))
> +		width = 1;
> +	if (of_property_read_u32_array(np, "srom-timing", timing, 7)) {

s/7/ARRAY_SIZE/

> +		pr_err("Could not decode SROMC configuration\n");

dev_err()

> +		return -ENXIO;

Here also I would prefer -EINVAL

> +	}
> +
> +	bank *= 4; /* Convert bank into shift/offset */
> +
> +	bw = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
> +	if (width == 2)
> +		bw |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
> +	bw <<= bank;
> +	bw |= __raw_readl(srom->reg_base + EXYNOS_SROM_BW) &
> +	      ~(EXYNOS_SROM_BW__CS_MASK << bank);

This is reversed pattern. First read, then set or clear bits and finally
write. It makes easier to understand what is the intention.

> +	__raw_writel(bw, srom->reg_base + EXYNOS_SROM_BW);
> +
> +	__raw_writel((timing[0] << EXYNOS_SROM_BCX__PMC__SHIFT) |
> +		    (timing[1] << EXYNOS_SROM_BCX__TACP__SHIFT) |
> +		    (timing[2] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
> +		    (timing[3] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
> +		    (timing[4] << EXYNOS_SROM_BCX__TACC__SHIFT) |
> +		    (timing[5] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
> +		    (timing[6] << EXYNOS_SROM_BCX__TACS__SHIFT),
> +		    srom->reg_base + EXYNOS_SROM_BC0 + bank);
> +
> +	return 0;
> +}
> +
>  static int exynos_srom_probe(struct platform_device *pdev)
>  {
> -	struct device_node *np;
> +	struct device_node *np, *child;
>  	struct exynos_srom *srom;
>  	struct device *dev = &pdev->dev;
>  
> @@ -100,6 +137,9 @@ static int exynos_srom_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  	}
>  
> +	for_each_child_of_node(np, child)
> +		decode_sromc(srom, child);

You ignore the return value here so bank may be not configured but
device probe will return 0.

Maybe clean up and fail the probe?

Best regards,
Krzysztof

> +
>  	return 0;
>  }
>  
> 

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Pavel Fedin Oct. 29, 2015, 6:54 a.m. UTC | #2
Hello!

> > +	for_each_child_of_node(np, child)
> > +		decode_sromc(srom, child);
> 
> You ignore the return value here so bank may be not configured but
> device probe will return 0.

 Yes, so that banks which are described correctly, will still be configured.

> Maybe clean up and fail the probe?

 I think it's not fatal, so cleanup is not necessary. May be dev_warn() in this case?

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia


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Krzysztof Kozlowski Oct. 29, 2015, 6:59 a.m. UTC | #3
On 29.10.2015 15:54, Pavel Fedin wrote:
>  Hello!
> 

Where is the contents of email and patch?

>>> +	for_each_child_of_node(np, child)
>>> +		decode_sromc(srom, child);
>>
>> You ignore the return value here so bank may be not configured but
>> device probe will return 0.
> 
>  Yes, so that banks which are described correctly, will still be configured.

But the system won't get any information about the failure. Device using
these banks should not probe in such case.

> 
>> Maybe clean up and fail the probe?
> 
>  I think it's not fatal, so cleanup is not necessary. May be dev_warn() in this case?

Now this is just silently ignoring return value (which is not needed
then) and not printing any errors. But that actually depends on previous
comment - whether the driver will fail the probe.

Best regards,
Krzysztof



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Pavel Fedin Oct. 29, 2015, 8:17 a.m. UTC | #4
Hello!

> But the system won't get any information about the failure. Device using
> these banks should not probe in such case.

 In order to achieve this effect, i believe, it's not enough to fail SROMc probe. Peripherials (such as smsc) should then be
declared as subnodes.
 There's one problem with this, however. I could not manage to do it. If i place device's node inside of SROMc node, it does not get
probed at all, and i don't really understand why. I tried to read the code and i suggest that only specific devices (like
compatible="simple-bus") are searched for sub-devices.
 OTOH, this patch (http://www.spinics.net/lists/arm-kernel/msg449703.html) perfectly worked, and generic timer node placed inside of
MCT node was perfectly probed by the kernel. So i still don't understand why i could not place smsc description inside of SROMc.
 May be you can help me with this?

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia


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diff mbox

Patch

diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
index 83c85f5..c22dc42 100644
--- a/arch/arm/mach-exynos/Kconfig
+++ b/arch/arm/mach-exynos/Kconfig
@@ -16,7 +16,7 @@  menuconfig ARCH_EXYNOS
 	select ARM_GIC
 	select COMMON_CLK_SAMSUNG
 	select EXYNOS_THERMAL
-	select EXYNOS_SROM if PM
+	select EXYNOS_SROM
 	select HAVE_ARM_SCU if SMP
 	select HAVE_S3C2410_I2C if I2C
 	select HAVE_S3C2410_WATCHDOG if WATCHDOG
diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig
index 2833b5b..ea4bc2a 100644
--- a/drivers/soc/samsung/Kconfig
+++ b/drivers/soc/samsung/Kconfig
@@ -8,6 +8,6 @@  config SOC_SAMSUNG
 
 config EXYNOS_SROM
 	bool
-	depends on ARM && ARCH_EXYNOS && PM
+	depends on ARM && ARCH_EXYNOS
 
 endmenu
diff --git a/drivers/soc/samsung/exynos-srom.c b/drivers/soc/samsung/exynos-srom.c
index 57a232d..6c8c56a 100644
--- a/drivers/soc/samsung/exynos-srom.c
+++ b/drivers/soc/samsung/exynos-srom.c
@@ -67,9 +67,46 @@  static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
 	return rd;
 }
 
+static int decode_sromc(struct exynos_srom *srom, struct device_node *np)
+{
+	u32 bank, width;
+	u32 timing[7];
+	u32 bw;
+
+	if (of_property_read_u32(np, "bank", &bank))
+		return -ENXIO;
+	if (of_property_read_u32(np, "width", &width))
+		width = 1;
+	if (of_property_read_u32_array(np, "srom-timing", timing, 7)) {
+		pr_err("Could not decode SROMC configuration\n");
+		return -ENXIO;
+	}
+
+	bank *= 4; /* Convert bank into shift/offset */
+
+	bw = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
+	if (width == 2)
+		bw |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
+	bw <<= bank;
+	bw |= __raw_readl(srom->reg_base + EXYNOS_SROM_BW) &
+	      ~(EXYNOS_SROM_BW__CS_MASK << bank);
+	__raw_writel(bw, srom->reg_base + EXYNOS_SROM_BW);
+
+	__raw_writel((timing[0] << EXYNOS_SROM_BCX__PMC__SHIFT) |
+		    (timing[1] << EXYNOS_SROM_BCX__TACP__SHIFT) |
+		    (timing[2] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
+		    (timing[3] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
+		    (timing[4] << EXYNOS_SROM_BCX__TACC__SHIFT) |
+		    (timing[5] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
+		    (timing[6] << EXYNOS_SROM_BCX__TACS__SHIFT),
+		    srom->reg_base + EXYNOS_SROM_BC0 + bank);
+
+	return 0;
+}
+
 static int exynos_srom_probe(struct platform_device *pdev)
 {
-	struct device_node *np;
+	struct device_node *np, *child;
 	struct exynos_srom *srom;
 	struct device *dev = &pdev->dev;
 
@@ -100,6 +137,9 @@  static int exynos_srom_probe(struct platform_device *pdev)
 		return -ENOMEM;
 	}
 
+	for_each_child_of_node(np, child)
+		decode_sromc(srom, child);
+
 	return 0;
 }