openwrt/target/linux/bcm27xx/patches-5.4/950-0423-ARM-dts-bcm2711-force-CMA-into-first-GB-of-memory.patch

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From 4bcb99a967998d255ef009bb0b6880ae99c6f6bf Mon Sep 17 00:00:00 2001
From: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Date: Wed, 6 Nov 2019 10:59:44 +0100
Subject: [PATCH] ARM: dts: bcm2711: force CMA into first GB of memory
arm64 places the CMA in ZONE_DMA32, which is not good enough for the
Raspberry Pi 4 since it contains peripherals that can only address the
first GB of memory. Explicitly place the CMA into that area.
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Stefan Wahren <wahrenst@gmx.net>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
arch/arm/boot/dts/bcm2711.dtsi | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
--- a/arch/arm/boot/dts/bcm2711.dtsi
+++ b/arch/arm/boot/dts/bcm2711.dtsi
@@ -12,6 +12,26 @@
interrupt-parent = <&gicv2>;
+ reserved-memory {
+ #address-cells = <2>;
+ #size-cells = <1>;
+ ranges;
+
+ /*
+ * arm64 reserves the CMA by default somewhere in ZONE_DMA32,
+ * that's not good enough for the BCM2711 as some devices can
+ * only address the lower 1G of memory (ZONE_DMA).
+ */
+ linux,cma {
+ compatible = "shared-dma-pool";
+ size = <0x2000000>; /* 32MB */
+ alloc-ranges = <0x0 0x00000000 0x40000000>;
+ reusable;
+ linux,cma-default;
+ };
+ };
+
+
soc {
/*
* Defined ranges: