[PATCH v2] arm64: dts: amlogic: t7: khadas-vim4: fix memory layout for 8GB RAM

[PATCH v2] arm64: dts: amlogic: t7: khadas-vim4: fix memory layout for 8GB RAM

[Nick Xie]

The Khadas VIM4 features 8GB of LPDDR4X RAM. The previous memory node
mapped a single incorrect region. This caused the kernel to map MMIO
and secure firmware (ATF/TrustZone) memory holes as standard RAM,
leading to an Asynchronous SError Interrupt during early boot
(paging_init) when the kernel attempted to clear those pages.

Fix this by splitting the 8GB memory layout into three separate
regions to properly avoid the memory holes (e.g., 0xe0000000 -
0xffffffff):
- 3.5GB @ 0x000000000
- 3.5GB @ 0x100000000
- 1.0GB @ 0x200000000

Signed-off-by: Nick Xie <nick@khadas.com>
Suggested-by: Ronald Claveau <linux-kernel-dev@aliel.fr>
---
Changes in v2:
- Removed leading zeroes in the memory node reg property.

Link to v1: https://lore.kernel.org/all/20260306031014.2421875-1-nick@khadas.com/

 arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
index 25b478e106451..f4c953034be39 100644
--- a/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
+++ b/arch/arm64/boot/dts/amlogic/amlogic-t7-a311d2-khadas-vim4.dts
@@ -17,7 +17,9 @@ aliases {
 
 	memory@0 {
 		device_type = "memory";
-		reg = <0x0 0x0 0x2 0x0>; /* 8 GB */
+		reg = <0x0 0x0 0x0 0xE0000000
+			0x1 0x0 0x0 0xE0000000
+			0x2 0x0 0x0 0x40000000>; /* 8 GB */
 	};
 
 	reserved-memory {
-- 
2.34.1

Re: [PATCH v2] arm64: dts: amlogic: t7: khadas-vim4: fix memory layout for 8GB RAM

[Neil Armstrong]

Hi,

On Thu, 19 Mar 2026 10:34:46 +0800, Nick Xie wrote:
> The Khadas VIM4 features 8GB of LPDDR4X RAM. The previous memory node
> mapped a single incorrect region. This caused the kernel to map MMIO
> and secure firmware (ATF/TrustZone) memory holes as standard RAM,
> leading to an Asynchronous SError Interrupt during early boot
> (paging_init) when the kernel attempted to clear those pages.
> 
> Fix this by splitting the 8GB memory layout into three separate
> regions to properly avoid the memory holes (e.g., 0xe0000000 -
> 0xffffffff):
> - 3.5GB @ 0x000000000
> - 3.5GB @ 0x100000000
> - 1.0GB @ 0x200000000
> 
> [...]

Thanks, Applied to https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux.git (v7.1/arm64-dt)

[1/1] arm64: dts: amlogic: t7: khadas-vim4: fix memory layout for 8GB RAM
      https://git.kernel.org/amlogic/c/4b3917cd8492d72e576b837f78c0c398bda4ec27

These changes has been applied on the intermediate git tree [1].

The v7.1/arm64-dt branch will then be sent via a formal Pull Request to the Linux SoC maintainers
for inclusion in their intermediate git branches in order to be sent to Linus during
the next merge window, or sooner if it's a set of fixes.

In the cases of fixes, those will be merged in the current release candidate
kernel and as soon they appear on the Linux master branch they will be
backported to the previous Stable and Long-Stable kernels [2].

The intermediate git branches are merged daily in the linux-next tree [3],
people are encouraged testing these pre-release kernels and report issues on the
relevant mailing-lists.

If problems are discovered on those changes, please submit a signed-off-by revert
patch followed by a corrective changeset.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/amlogic/linux.git
[2] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
[3] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

-- 
Neil