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

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

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;
>  }
>  
>