dts: bcm2712-rpi: Give PIO the "heavy" DMA channels

PIO benefits from increased DMA bandwidth when used with DMA channels
0 or 1, because they support longer bursts. Add DMA channel selection
attributes to prevent other users from claiming them.

Signed-off-by: Phil Elwell <phil@raspberrypi.com>

Author: pelwell

arch/arm64/boot/dts/broadcom/bcm2712-rpi.dtsi

@@ -2,6 +2,9 @@
 
 #include <dt-bindings/power/raspberrypi-power.h>
 
+#define DMA_SEL_WANTHEAVY       (1 << 8)
+#define DMA_SEL_ONLYHEAVY       (1 << 9)
+
 &soc {
 	firmware: firmware {
 		compatible = "raspberrypi,bcm2835-firmware", "simple-mfd";
@@ -91,7 +94,21 @@
 	};
 };
 
+&rp1_dma {
+	snps,sel-require =  <DMA_SEL_WANTHEAVY DMA_SEL_WANTHEAVY 0 0 0 0 0 0>;
+	snps,sel-preclude = <0 0 DMA_SEL_ONLYHEAVY DMA_SEL_ONLYHEAVY DMA_SEL_ONLYHEAVY
+			     DMA_SEL_ONLYHEAVY DMA_SEL_ONLYHEAVY DMA_SEL_ONLYHEAVY>;
+};
+
 pio: &rp1_pio {
+	dmas = <&rp1_dma (RP1_DMA_PIO_CH0_TX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH0_RX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH1_TX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH1_RX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH2_TX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH2_RX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH3_TX | DMA_SEL_WANTHEAVY)>,
+			<&rp1_dma (RP1_DMA_PIO_CH3_RX | DMA_SEL_WANTHEAVY)>;
 	status = "okay";
 };