Hi Nicolas, On 10/01/2020 17:29, Nicolas Saenz Julienne wrote:
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@xxxxxxx> --- If this doesn't make it into v5.5 I'd be tempted to add: Fixes: d98a8dbdaec6 ("ARM: dts: bcm2711: force CMA into first GB of memory") arch/arm/boot/dts/bcm2711.dtsi | 33 +++++++++++++-------------------- arch/arm/boot/dts/bcm283x.dtsi | 13 +++++++++++++ 2 files changed, 26 insertions(+), 20 deletions(-) diff --git a/arch/arm/boot/dts/bcm2711.dtsi b/arch/arm/boot/dts/bcm2711.dtsi index 8687534d4528..c8e4041308e0 100644 --- a/arch/arm/boot/dts/bcm2711.dtsi +++ b/arch/arm/boot/dts/bcm2711.dtsi @@ -12,26 +12,6 @@ / {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: @@ -869,6 +849,19 @@ pin-rts { }; };+&rmem {+ #address-cells = <2>; +}; + +&cma { + /* + * 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). + */ + alloc-ranges = <0x0 0x00000000 0x40000000>; +}; + &i2c0 { compatible = "brcm,bcm2711-i2c", "brcm,bcm2835-i2c"; interrupts = <GIC_SPI 117 IRQ_TYPE_LEVEL_HIGH>; diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi index 839491628e87..6128baed83c2 100644 --- a/arch/arm/boot/dts/bcm283x.dtsi +++ b/arch/arm/boot/dts/bcm283x.dtsi @@ -30,6 +30,19 @@ chosen { 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>;
For what it's worth, Reviewed-by: Phil Elwell <phil@xxxxxxxxxxxxxxx> Phil
