From 7a5a48e8a30fc9f1289b31699e1f39a85f6298fe Mon Sep 17 00:00:00 2001
From: Chen Jiali <chenjiali@radxa.com>
Date: Thu, 5 Sep 2024 17:02:02 +0800
Subject: [PATCH] feat: add rockchip-uart-dma

* closes https://github.com/radxa-pkg/radxa-overlays/issues/366
---
 .../arm64/boot/dts/rockchip/overlays/Makefile |  3 +-
 .../rockchip/overlays/rockchip-uart-dma.dts   | 53 +++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 arch/arm64/boot/dts/rockchip/overlays/rockchip-uart-dma.dts

diff --git a/arch/arm64/boot/dts/rockchip/overlays/Makefile b/arch/arm64/boot/dts/rockchip/overlays/Makefile
index 72127751..1613d571 100644
--- a/arch/arm64/boot/dts/rockchip/overlays/Makefile
+++ b/arch/arm64/boot/dts/rockchip/overlays/Makefile
@@ -564,7 +564,8 @@ dtb-$(CONFIG_CPU_RK3588) += \
 	rock-5t-radxa-display-10fhd.dtbo \
 	rock-5t-radxa-display-10hd.dtbo
 
-dtb-$(CONFIG_ARCH_ROCKCHIP) += rockchip-watchdog.dtbo
+dtb-$(CONFIG_ARCH_ROCKCHIP) += rockchip-watchdog.dtbo \
+	rockchip-uart-dma.dtbo
 
 dtbotxt-$(CONFIG_ARCH_ROCKCHIP) += \
 	README.overlays
diff --git a/arch/arm64/boot/dts/rockchip/overlays/rockchip-uart-dma.dts b/arch/arm64/boot/dts/rockchip/overlays/rockchip-uart-dma.dts
new file mode 100644
index 00000000..c7dbeda0
--- /dev/null
+++ b/arch/arm64/boot/dts/rockchip/overlays/rockchip-uart-dma.dts
@@ -0,0 +1,53 @@
+/dts-v1/;
+/plugin/;
+
+/ {
+	metadata {
+		title = "Enable DMA transfer mode for all UARTs";
+		compatible = "rockchip,rk3566", "rockchip,rk3568", "rockchip,rk3588";
+		category = "misc";
+		description = "Enable DMA transfer mode for all UARTs.
+DMA mode can help alleviating the CPU load when the data rate is high.
+It is not necessary to enable it at low data rate, as DMA requires additional resources to set up.";
+	};
+};
+
+&uart0 {
+	dma-names = "tx", "rx";
+};
+
+&uart1 {
+	dma-names = "tx", "rx";
+};
+
+&uart2 {
+	dma-names = "tx", "rx";
+};
+
+&uart3 {
+	dma-names = "tx", "rx";
+};
+
+&uart4 {
+	dma-names = "tx", "rx";
+};
+
+&uart5 {
+	dma-names = "tx", "rx";
+};
+
+&uart6 {
+	dma-names = "tx", "rx";
+};
+
+&uart7 {
+	dma-names = "tx", "rx";
+};
+
+&uart8 {
+	dma-names = "tx", "rx";
+};
+
+&uart9 {
+	dma-names = "tx", "rx";
+};