[Replicant] [PATCH] ARM: dts: exynos4412-*: decrease memory to account for unusable region

[Artur Weber]

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 at grimler.se> # i9300, i9305
Signed-off-by: Artur Weber <aweber.kernel at gmail.com>
---

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@grimler.se/
...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@samsung.com/
---
 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 at 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 at 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 at 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 at 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 at gmail.com>