[PATCH v1 4/9] stm32mp: dram_init: Limit DDR usage under 4GB boundary for STM32MP

[Patrick DELAUNAY]

Hi,

On 10/27/23 16:42, Patrice Chotard wrote:
> Limit DDR usage under 4GB boundary on STM32MP regardless of
> memory size declared in device tree.
>
> Signed-off-by: Patrice Chotard <patrice.chotard at foss.st.com>
> ---
>
>   arch/arm/mach-stm32mp/dram_init.c | 8 +++++++-
>   1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-stm32mp/dram_init.c b/arch/arm/mach-stm32mp/dram_init.c
> index cb35ed60ca1..fb1208fc5d5 100644
> --- a/arch/arm/mach-stm32mp/dram_init.c
> +++ b/arch/arm/mach-stm32mp/dram_init.c
> @@ -52,9 +52,15 @@ phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
>   	if (!total_size)
>   		return gd->ram_top;
>   
> +	/*
> +	 * make sure U-Boot uses address space below 4GB boundaries even
> +	 * if the effective available memory is bigger
> +	 */
> +	gd->ram_top = clamp_val(gd->ram_top, 0, SZ_4G - 1);
> +
>   	/* found enough not-reserved memory to relocated U-Boot */
>   	lmb_init(&lmb);
> -	lmb_add(&lmb, gd->ram_base, get_effective_memsize());
> +	lmb_add(&lmb, gd->ram_base, gd->ram_top - gd->ram_base);
>   	boot_fdt_add_mem_rsv_regions(&lmb, (void *)gd->fdt_blob);
>   	/* add 8M for reserved memory for display, fdt, gd,... */
>   	size = ALIGN(SZ_8M + CONFIG_SYS_MALLOC_LEN + total_size, MMU_SECTION_SIZE),


Reviewed-by: Patrick Delaunay <patrick.delaunay at foss.st.com>

Thanks
Patrick