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From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 4 Sep 2020 18:42:42 +0200
Subject: [PATCH] pci: pcie-mediatek: add support for coherent DMA
It improves performance by eliminating the need for a cache flush for DMA on
attached devices
Signed-off-by: Felix Fietkau <nbd@nbd.name>
---
--- a/arch/arm64/boot/dts/mediatek/mt7622.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt7622.dtsi
@@ -813,6 +813,8 @@
reg = <0 0x1a143000 0 0x1000>;
reg-names = "port0";
mediatek,pcie-cfg = <&pciecfg>;
+ mediatek,hifsys = <&hifsys>;
+ mediatek,cci-control = <&cci_control2>;
#address-cells = <3>;
#size-cells = <2>;
interrupts = <GIC_SPI 228 IRQ_TYPE_LEVEL_LOW>;
@@ -830,6 +832,7 @@
bus-range = <0x00 0xff>;
ranges = <0x82000000 0 0x20000000 0x0 0x20000000 0 0x8000000>;
status = "disabled";
+ dma-coherent;
slot0: pcie@0,0 {
reg = <0x0000 0 0 0 0>;
@@ -856,6 +859,8 @@
reg = <0 0x1a145000 0 0x1000>;
reg-names = "port1";
mediatek,pcie-cfg = <&pciecfg>;
+ mediatek,hifsys = <&hifsys>;
+ mediatek,cci-control = <&cci_control2>;
#address-cells = <3>;
#size-cells = <2>;
interrupts = <GIC_SPI 229 IRQ_TYPE_LEVEL_LOW>;
@@ -874,6 +879,7 @@
bus-range = <0x00 0xff>;
ranges = <0x82000000 0 0x28000000 0x0 0x28000000 0 0x8000000>;
status = "disabled";
+ dma-coherent;
slot1: pcie@1,0 {
reg = <0x0800 0 0 0 0>;
--- a/drivers/pci/controller/pcie-mediatek.c
+++ b/drivers/pci/controller/pcie-mediatek.c
@@ -20,6 +20,7 @@
#include <linux/of_address.h>
#include <linux/of_pci.h>
#include <linux/of_platform.h>
+#include <linux/of_address.h>
#include <linux/pci.h>
#include <linux/phy/phy.h>
#include <linux/platform_device.h>
@@ -139,6 +140,11 @@
#define PCIE_LINK_STATUS_V2 0x804
#define PCIE_PORT_LINKUP_V2 BIT(10)
+/* DMA channel mapping */
+#define HIFSYS_DMA_AG_MAP 0x008
+#define HIFSYS_DMA_AG_MAP_PCIE0 BIT(0)
+#define HIFSYS_DMA_AG_MAP_PCIE1 BIT(1)
+
struct mtk_pcie_port;
/**
@@ -1042,6 +1048,27 @@ static int mtk_pcie_setup(struct mtk_pci
struct mtk_pcie_port *port, *tmp;
int err;
+ if (of_dma_is_coherent(node)) {
+ struct regmap *con;
+ u32 mask;
+
+ con = syscon_regmap_lookup_by_phandle(node,
+ "mediatek,cci-control");
+ /* enable CPU/bus coherency */
+ if (!IS_ERR(con))
+ regmap_write(con, 0, 3);
+
+ con = syscon_regmap_lookup_by_phandle(node,
+ "mediatek,hifsys");
+ if (IS_ERR(con)) {
+ dev_err(dev, "missing hifsys node\n");
+ return PTR_ERR(con);
+ }
+
+ mask = HIFSYS_DMA_AG_MAP_PCIE0 | HIFSYS_DMA_AG_MAP_PCIE1;
+ regmap_update_bits(con, HIFSYS_DMA_AG_MAP, mask, mask);
+ }
+
for_each_available_child_of_node(node, child) {
int slot;
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