arm64: dts: mediatek: mt6795: Add support for APDMA and wire up UART DMAs

This SoC has a DMA controller with tx/rx channels for all of the
UART controller IPs: add the apdma node and wire up the DMAs on
all controllers.
When one of the UART controllers is used as a serial console,
the DMA will be automatically ignored.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221027095504.37432-4-angelogioacchino.delregno@collabora.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt6795.dtsi

@@ -316,6 +316,8 @@ uart0: serial@11002000 {
 			interrupts = <GIC_SPI 91 IRQ_TYPE_LEVEL_LOW>;
 			clocks = <&pericfg CLK_PERI_UART0_SEL>, <&pericfg CLK_PERI_UART0>;
 			clock-names = "baud", "bus";
+			dmas = <&apdma 0>, <&apdma 1>;
+			dma-names = "tx", "rx";
 			status = "disabled";
 		};
 
@@ -326,9 +328,37 @@ uart1: serial@11003000 {
 			interrupts = <GIC_SPI 92 IRQ_TYPE_LEVEL_LOW>;
 			clocks = <&pericfg CLK_PERI_UART1_SEL>, <&pericfg CLK_PERI_UART1>;
 			clock-names = "baud", "bus";
+			dmas = <&apdma 2>, <&apdma 3>;
+			dma-names = "tx", "rx";
 			status = "disabled";
 		};
 
+		apdma: dma-controller@11000380 {
+			compatible = "mediatek,mt6795-uart-dma",
+				     "mediatek,mt6577-uart-dma";
+			reg = <0 0x11000380 0 0x60>,
+			      <0 0x11000400 0 0x60>,
+			      <0 0x11000480 0 0x60>,
+			      <0 0x11000500 0 0x60>,
+			      <0 0x11000580 0 0x60>,
+			      <0 0x11000600 0 0x60>,
+			      <0 0x11000680 0 0x60>,
+			      <0 0x11000700 0 0x60>;
+			interrupts = <GIC_SPI 103 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 104 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 105 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 106 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 107 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 108 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 109 IRQ_TYPE_LEVEL_LOW>,
+				     <GIC_SPI 110 IRQ_TYPE_LEVEL_LOW>;
+			dma-requests = <8>;
+			clocks = <&pericfg CLK_PERI_AP_DMA>;
+			clock-names = "apdma";
+			mediatek,dma-33bits;
+			#dma-cells = <1>;
+		};
+
 		uart2: serial@11004000 {
 			compatible = "mediatek,mt6795-uart",
 				     "mediatek,mt6577-uart";
@@ -336,6 +366,8 @@ uart2: serial@11004000 {
 			interrupts = <GIC_SPI 93 IRQ_TYPE_LEVEL_LOW>;
 			clocks = <&pericfg CLK_PERI_UART2_SEL>, <&pericfg CLK_PERI_UART2>;
 			clock-names = "baud", "bus";
+			dmas = <&apdma 4>, <&apdma 5>;
+			dma-names = "tx", "rx";
 			status = "disabled";
 		};
 
@@ -346,6 +378,8 @@ uart3: serial@11005000 {
 			interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_LOW>;
 			clocks = <&pericfg CLK_PERI_UART3_SEL>, <&pericfg CLK_PERI_UART3>;
 			clock-names = "baud", "bus";
+			dmas = <&apdma 6>, <&apdma 7>;
+			dma-names = "tx", "rx";
 			status = "disabled";
 		};
 	};