[PATCH v5] ARM64: dts: meson-gx: Add firmware reserved memory zones

[narmstrong@baylibre.com (Neil Armstrong)]

The Amlogic Meson GXBB/GXL/GXM secure monitor uses part of the memory space,
this patch adds these reserved zones.

Without such reserved memory zones, running the following stress command :
$ stress-ng --vm 16 --vm-bytes 128M --timeout 10s
multiple times:

Could lead to the following kernel crashes :
[   46.937975] Bad mode in Error handler detected on CPU1, code 0xbf000000 -- SError
...
[   47.058536] Internal error: Attempting to execute userspace memory: 8600000f [#3] PREEMPT SMP
...
Instead of the OOM killer.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 arch/arm64/boot/dts/amlogic/meson-gx.dtsi | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Changes since v4 at [5]:
- Move start of ddr memory to reserved-memory node
- Drop memory node move
- Fix typo in sizes

Changes since resent v2 at [4]:
- Fix invalid comment of useable memory attributes

Changes since original v2 at [3]:
- Typo in commit 2GiB -> 1GiB, 4GiB -> 2GiB

Changes since v2 at [2]:
- Moved all memory node out of dtsi
- Added comment about useable memory
- Fixed comment about secmon reserved zone

Changes since v1 at [1] :
- Renamed reg into linux,usable-memory to ovveride u-boot memory
- only kept secmon memory zone

[1] http://lkml.kernel.org/r/20161212101801.28491-1-narmstrong at baylibre.com
[2] http://lkml.kernel.org/r/1483105232-6242-1-git-send-email-narmstrong at baylibre.com
[3] http://lkml.kernel.org/r/1484128128-22454-1-git-send-email-narmstrong at baylibre.com
[4] http://lkml.kernel.org/r/1484128540-22662-1-git-send-email-narmstrong at baylibre.com
[5] http://lkml.kernel.org/r/1484129414-23325-1-git-send-email-narmstrong at baylibre.com

diff --git a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
index eada0b5..63d52b7 100644
--- a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
+++ b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi
@@ -55,6 +55,24 @@
 	#address-cells = <2>;
 	#size-cells = <2>;
 
+	reserved-memory {
+		#address-cells = <2>;
+		#size-cells = <2>;
+		ranges;
+
+		/* 16 MiB reserved for Hardware ROM Firmware */
+		hwrom: hwrom {
+			reg = <0x0 0x0 0x0 0x1000000>;
+			no-map;
+		};
+
+		/* 2 MiB reserved for ARM Trusted Firmware (BL31) */
+		secmon: secmon {
+			reg = <0x0 0x10000000 0x0 0x200000>;
+			no-map;
+		};
+	};
+
 	cpus {
 		#address-cells = <0x2>;
 		#size-cells = <0x0>;
-- 
1.9.1