[PATCH RFC] rockchip: rk3588: include all addressable DRAM in memory map

[Kever Yang]

On 2026/2/3 17:58, Quentin Schulz wrote:
> From: Quentin Schulz <quentin.schulz at cherry.de>
>
> The ATAGS set by Rockchip DDR init blob[1] specify DRAM banks above the
> first addressable 4GiB which we haven't done in the mem_map for RK3588
> yet.
>
> For 4GiB DRAM, the 256MiB missing from the first addressable 4GiB (due
> to MMIO) are accessible at the end of the 8GiB address space. For 8GiB,
> 4-8GiB address space is used for the additional 4GiB and the missing
> 256MiB are at the end of 12GiB address space. For 12, 4-12GiB and the
> missing 256MiB at the end of 20GiB address space. For 16GiB, 4-~16GiB
> with two holes (reasons unknown) around 16GiB and the missing 256MiB is
> at the end of 20GiB address space. For 32GiB, 4-16~GiB with two holes
> and then 16GiB to 32GiB address space (so likely missing 256MiB from
> MMIO address space).
>
> [1] https://gist.github.com/Kwiboo/1c020d37e3adbc9d0d79dc003d921977
>
> Suggested-by: Jonas Karlman <jonas at kwiboo.se>
> Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>
Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
> This is the RK3588 counterpart to RK3568's[1] which is required for
> Marek's patch[2] to not crash RK35xx series of SoCs when booting.
>
> This (plus patch[2]) has been tested on 4, 8 and 16GiB by TFTP'ing a
> kernel and DTB into the various DRAM regions above 4GiB and booting this
> kernel+dtb combination.
>
> Note that I have zero clue as to what this is actually doing as I cannot
> understand where this mem_map is actually used, hence the RFC.
>
> [1] https://lore.kernel.org/u-boot/20260129193153.2232395-1-jonas@kwiboo.se/
> [2] https://lore.kernel.org/u-boot/20260127234856.1503030-1-marek.vasut+renesas@mailbox.org/
> ---
>   arch/arm/mach-rockchip/rk3588/rk3588.c | 18 ++++++++++++++++++
>   1 file changed, 18 insertions(+)
>
> diff --git a/arch/arm/mach-rockchip/rk3588/rk3588.c b/arch/arm/mach-rockchip/rk3588/rk3588.c
> index 55d2caab4fe..438642ca529 100644
> --- a/arch/arm/mach-rockchip/rk3588/rk3588.c
> +++ b/arch/arm/mach-rockchip/rk3588/rk3588.c
> @@ -87,6 +87,24 @@ static struct mm_region rk3588_mem_map[] = {
>   			 PTE_BLOCK_NON_SHARE |
>   			 PTE_BLOCK_PXN | PTE_BLOCK_UXN
>   	},  {
> +		.virt = 0x100000000UL,
> +		.phys = 0x100000000UL,
> +		.size = 0x2fc000000UL,
> +		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> +			 PTE_BLOCK_INNER_SHARE
> +	}, {
> +		.virt = 0x3fc500000UL,
> +		.phys = 0x3fc500000UL,
> +		.size = 0x3a00000UL,
> +		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> +			 PTE_BLOCK_INNER_SHARE
> +	}, {
> +		.virt = 0x400000000UL,
> +		.phys = 0x400000000UL,
> +		.size = 0x400000000UL,
> +		.attrs = PTE_BLOCK_MEMTYPE(MT_NORMAL) |
> +			 PTE_BLOCK_INNER_SHARE
> +	}, {
>   		.virt = 0x900000000,
>   		.phys = 0x900000000,
>   		.size = 0x150000000,
>
> ---
> base-commit: 16fcbcb2ee25ea042c1e9cfbc04f7a5554746b64
> change-id: 20260202-rk3588-mem-map-053661aa7e46
>
> Best regards,
> --
> Quentin Schulz <quentin.schulz at cherry.de>