The last 4 MiB of RAM on those devices is likely used by trustzone firmware, and is unusable under Linux. Change the device tree memory node accordingly. The proprietary bootloader (S-BOOT) passes these memory ranges through ATAG_MEM; this change allows us to have the correct memory ranges without relying on ATAG_MEM. Tested-by: Henrik Grimler <henrik@xxxxxxxxxx> # i9300, i9305 Signed-off-by: Artur Weber <aweber.kernel@xxxxxxxxx> --- This follows a similar fix implemented for the exynos5420-based Galaxy Tab boards: https://lore.kernel.org/all/20240130-galaxy-tab-s-cleanup-v1-3-d4e17857241d@xxxxxxxxxx/ ...which in turn is inspired by another fix applied to exynos5422 Odroid devices, 6591a02e17e6 ("ARM: dts: reduce total RAM by 22 MiB for exynos5422-odroidxu3"): https://lore.kernel.org/all/1421842972-25807-1-git-send-email-m.szyprowski@xxxxxxxxxxx/ --- arch/arm/boot/dts/samsung/exynos4412-i9300.dts | 2 +- arch/arm/boot/dts/samsung/exynos4412-i9305.dts | 2 +- arch/arm/boot/dts/samsung/exynos4412-n710x.dts | 2 +- arch/arm/boot/dts/samsung/exynos4412-p4note.dtsi | 2 +- 4 files changed, 4 insertions(+), 4 deletions(-) diff --git a/arch/arm/boot/dts/samsung/exynos4412-i9300.dts b/arch/arm/boot/dts/samsung/exynos4412-i9300.dts index 61aca5798f38..b79d456e976d 100644 --- a/arch/arm/boot/dts/samsung/exynos4412-i9300.dts +++ b/arch/arm/boot/dts/samsung/exynos4412-i9300.dts @@ -18,7 +18,7 @@ / { memory@40000000 { device_type = "memory"; - reg = <0x40000000 0x40000000>; + reg = <0x40000000 0x3fc00000>; }; }; diff --git a/arch/arm/boot/dts/samsung/exynos4412-i9305.dts b/arch/arm/boot/dts/samsung/exynos4412-i9305.dts index 77083f1a8273..1048ef5d9bc3 100644 --- a/arch/arm/boot/dts/samsung/exynos4412-i9305.dts +++ b/arch/arm/boot/dts/samsung/exynos4412-i9305.dts @@ -11,7 +11,7 @@ / { memory@40000000 { device_type = "memory"; - reg = <0x40000000 0x80000000>; + reg = <0x40000000 0x7fc00000>; }; }; diff --git a/arch/arm/boot/dts/samsung/exynos4412-n710x.dts b/arch/arm/boot/dts/samsung/exynos4412-n710x.dts index 0a151437fc73..eee1000dea92 100644 --- a/arch/arm/boot/dts/samsung/exynos4412-n710x.dts +++ b/arch/arm/boot/dts/samsung/exynos4412-n710x.dts @@ -9,7 +9,7 @@ / { memory@40000000 { device_type = "memory"; - reg = <0x40000000 0x80000000>; + reg = <0x40000000 0x7fc00000>; }; /* bootargs are passed in by bootloader */ diff --git a/arch/arm/boot/dts/samsung/exynos4412-p4note.dtsi b/arch/arm/boot/dts/samsung/exynos4412-p4note.dtsi index 0b89d5682f85..95fc63295860 100644 --- a/arch/arm/boot/dts/samsung/exynos4412-p4note.dtsi +++ b/arch/arm/boot/dts/samsung/exynos4412-p4note.dtsi @@ -23,7 +23,7 @@ / { memory@40000000 { device_type = "memory"; - reg = <0x40000000 0x80000000>; + reg = <0x40000000 0x7fc00000>; }; aliases { --- base-commit: 0f1dd5e91e2ba3990143645faff2bcce2d99778e change-id: 20240217-exynos4-memsize-fix-dccdb9eb75d6 Best regards, -- Artur Weber <aweber.kernel@xxxxxxxxx>
