[PATCH] ARM: stm32mp: ddrctl: add STM32MP131 RAM size querying support

[PATCH] ARM: stm32mp: ddrctl: add STM32MP131 RAM size querying support

[Ahmad Fatoum]

buswidth is read from HW. With nb_bytes == 2, there is a possibility
that we get a zero size out here, if driver and device are
mismatched, e.g. because barebox is booted in FIP with mismatched
external device tree.

As this runs very early before relocation, round up instead of crashing
to be a bit more on the safe side.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 arch/arm/mach-stm32mp/ddrctrl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-stm32mp/ddrctrl.c b/arch/arm/mach-stm32mp/ddrctrl.c
index 7f0944d7e77c..ed211cf58ebc 100644
--- a/arch/arm/mach-stm32mp/ddrctrl.c
+++ b/arch/arm/mach-stm32mp/ddrctrl.c
@@ -101,7 +101,8 @@ static unsigned long ddrctrl_addrmap_ramsize(struct stm32mp1_ddrctl __iomem *d,
 	if (LINE_UNUSED(reg, ADDRMAP6_ROW_B13)) rows--;
 	if (LINE_UNUSED(reg, ADDRMAP6_ROW_B12)) rows--;
 
-	return memory_sdram_size(cols, rows, BIT(banks), nb_bytes / BIT(buswidth));
+	return memory_sdram_size(cols, rows, BIT(banks),
+				 DIV_ROUND_UP(nb_bytes, BIT(buswidth)));
 }
 
 static inline unsigned ddrctrl_ramsize(void __iomem *base, unsigned nb_bytes)
-- 
2.30.2


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Re: [PATCH] ARM: stm32mp: ddrctl: add STM32MP131 RAM size querying support

[Sascha Hauer]

On Wed, Feb 23, 2022 at 12:38:47PM +0100, Ahmad Fatoum wrote:
> buswidth is read from HW. With nb_bytes == 2, there is a possibility
> that we get a zero size out here, if driver and device are
> mismatched, e.g. because barebox is booted in FIP with mismatched
> external device tree.
> 
> As this runs very early before relocation, round up instead of crashing
> to be a bit more on the safe side.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> ---
>  arch/arm/mach-stm32mp/ddrctrl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)

Applied, thanks

Sascha

> 
> diff --git a/arch/arm/mach-stm32mp/ddrctrl.c b/arch/arm/mach-stm32mp/ddrctrl.c
> index 7f0944d7e77c..ed211cf58ebc 100644
> --- a/arch/arm/mach-stm32mp/ddrctrl.c
> +++ b/arch/arm/mach-stm32mp/ddrctrl.c
> @@ -101,7 +101,8 @@ static unsigned long ddrctrl_addrmap_ramsize(struct stm32mp1_ddrctl __iomem *d,
>  	if (LINE_UNUSED(reg, ADDRMAP6_ROW_B13)) rows--;
>  	if (LINE_UNUSED(reg, ADDRMAP6_ROW_B12)) rows--;
>  
> -	return memory_sdram_size(cols, rows, BIT(banks), nb_bytes / BIT(buswidth));
> +	return memory_sdram_size(cols, rows, BIT(banks),
> +				 DIV_ROUND_UP(nb_bytes, BIT(buswidth)));
>  }
>  
>  static inline unsigned ddrctrl_ramsize(void __iomem *base, unsigned nb_bytes)
> -- 
> 2.30.2
> 
> 
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