On 06/11/2026 08:37, Vandhiadevan Karunamoorthy wrote:
> qcom_parse_memory() set gd->ram_size to the span from the start of the
> first bank to the end of the last one, so that the relocation address
> computed in setup_ram_config() lands at the end of the highest bank. With
> sparse banks, such as 2 GiB below 4 GiB plus 2 GiB at 32 GiB, the DRAM
> line then reports '32 GiB (total 4 GiB)'.
>
> Make gd->ram_size the sum of the bank sizes and provide the relocation
> address through board_get_usable_ram_top() instead, taking the end of the
> highest bank. Boards with a single bank are unchanged. On boards with
> holes between the banks, the values derived from gd->ram_size, such as
> bootm_size, now reflect the real amount of RAM.
>
> Signed-off-by: Vandhiadevan Karunamoorthy
> <[email protected]>
Reviewed-by: Casey Connolly <[email protected]>
> ---
> arch/arm/mach-snapdragon/dram.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-snapdragon/dram.c b/arch/arm/mach-snapdragon/dram.c
> index 732e2bde2d2..af5e19960d9 100644
> --- a/arch/arm/mach-snapdragon/dram.c
> +++ b/arch/arm/mach-snapdragon/dram.c
> @@ -20,6 +20,15 @@ static struct {
> phys_size_t size;
> } prevbl_ddr_banks[CONFIG_NR_DRAM_BANKS] __section(".data") = { 0 };
>
> +/* End of the highest memory bank, U-Boot is relocated to just below it */
> +static phys_addr_t qcom_ram_end __section(".data");
> +
> +/* Override the generic helper, gd->ram_size no longer spans to the highest
> bank */
> +phys_addr_t board_get_usable_ram_top(phys_size_t total_size)
> +{
> + return qcom_ram_end ?: gd->ram_top;
> +}
> +
> int dram_init(void)
> {
> /*
> @@ -198,6 +207,10 @@ static void qcom_parse_memory_dt(const fdt64_t *fdt, int
> *banks, phys_addr_t *ra
> * to correctly determine the relocation address for U-Boot is to parse all
> * memory regions and find the highest valid address.
> *
> + * gd->ram_size is set to the sum of the bank sizes, as the banks may be
> + * sparse. The relocation address is provided separately, as the end of the
> + * highest bank, by board_get_usable_ram_top().
> + *
> * We can't use fdtdec_setup_memory_banksize() since it stores the result in
> * gd->bd, which is not yet allocated.
> *
> @@ -213,6 +226,7 @@ int qcom_parse_memory(const void *fdt, bool
> fdt_is_internal)
> {
> phys_addr_t ram_end = 0;
> int banks;
> + size_t i;
>
> qcom_memmap_source = fdt_is_internal ? QCOM_MEMMAP_SOURCE_INTERNAL_FDT
> : QCOM_MEMMAP_SOURCE_EXTERNAL_FDT;
> @@ -234,7 +248,10 @@ int qcom_parse_memory(const void *fdt, bool
> fdt_is_internal)
> qsort(prevbl_ddr_banks, banks, sizeof(prevbl_ddr_banks[0]),
> ddr_bank_cmp);
>
> gd->ram_base = prevbl_ddr_banks[0].start;
> - gd->ram_size = ram_end - gd->ram_base;
> + gd->ram_size = 0;
> + for (i = 0; i < ARRAY_SIZE(prevbl_ddr_banks); i++)
> + gd->ram_size += prevbl_ddr_banks[i].size;
> + qcom_ram_end = ram_end;
>
> return 0;
> }
>
> ---
> base-commit: d1d45c926a571fb6c1e6d7105c280833646915ea
> change-id: 20261105-dram-sum-banks-baea15fe7734
>
> Best regards,
> --
> Vandhiadevan Karunamoorthy <[email protected]>
--
// Casey (she/her)
