ARM: dts: bcm283x: Unify CMA configuration

With the introduction of the Raspberry Pi 4 we were forced to explicitly
configure CMA's location, since arm64 defaults it into the ZONE_DMA32
memory area, which is not good enough to perform DMA operations on that
device. To bypass this limitation a dedicated CMA DT node was created,
explicitly indicating the acceptable memory range and size.

That said, compatibility between boards is a must on the Raspberry Pi
ecosystem so this creates a common CMA DT node so as for DT overlays to
be able to update CMA's properties regardless of the board being used.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Reviewed-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
index 5219339fc27c..9fb0418595fc 100644
--- a/arch/arm/boot/dts/bcm283x.dtsi
+++ b/arch/arm/boot/dts/bcm283x.dtsi
@@ -30,6 +30,19 @@
 		stdout-path = "serial0:115200n8";
 	};
 
+	rmem: reserved-memory {
+		#address-cells = <1>;
+		#size-cells = <1>;
+		ranges;
+
+		cma: linux,cma {
+			compatible = "shared-dma-pool";
+			size = <0x4000000>; /* 64MB */
+			reusable;
+			linux,cma-default;
+		};
+	};
+
 	thermal-zones {
 		cpu_thermal: cpu-thermal {
 			polling-delay-passive = <0>;