ethernet: mediatek: mtk_eth_soc: add support for initializing the PPE

The PPE (packet processing engine) is used to offload NAT/routed or even
bridged flows. This patch brings up the PPE and uses it to get a packet
hash. It also contains some functionality that will be used to bring up
flow offloading.

Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/ethernet/mediatek/Makefile

@@ -4,5 +4,5 @@
 #
 
 obj-$(CONFIG_NET_MEDIATEK_SOC) += mtk_eth.o
-mtk_eth-y := mtk_eth_soc.o mtk_sgmii.o mtk_eth_path.o
+mtk_eth-y := mtk_eth_soc.o mtk_sgmii.o mtk_eth_path.o mtk_ppe.o mtk_ppe_debugfs.o
 obj-$(CONFIG_NET_MEDIATEK_STAR_EMAC) += mtk_star_emac.o

drivers/net/ethernet/mediatek/mtk_eth_soc.c

@@ -2255,12 +2255,17 @@ static int mtk_open(struct net_device *dev)
 
 	/* we run 2 netdevs on the same dma ring so we only bring it up once */
 	if (!refcount_read(&eth->dma_refcnt)) {
-		int err = mtk_start_dma(eth);
+		u32 gdm_config = MTK_GDMA_TO_PDMA;
+		int err;
 
+		err = mtk_start_dma(eth);
 		if (err)
 			return err;
 
-		mtk_gdm_config(eth, MTK_GDMA_TO_PDMA);
+		if (eth->soc->offload_version && mtk_ppe_start(&eth->ppe) == 0)
+			gdm_config = MTK_GDMA_TO_PPE;
+
+		mtk_gdm_config(eth, gdm_config);
 
 		napi_enable(&eth->tx_napi);
 		napi_enable(&eth->rx_napi);
@@ -2327,6 +2332,9 @@ static int mtk_stop(struct net_device *dev)
 
 	mtk_dma_free(eth);
 
+	if (eth->soc->offload_version)
+		mtk_ppe_stop(&eth->ppe);
+
 	return 0;
 }
 
@@ -3055,6 +3063,13 @@ static int mtk_probe(struct platform_device *pdev)
 			goto err_free_dev;
 	}
 
+	if (eth->soc->offload_version) {
+		err = mtk_ppe_init(&eth->ppe, eth->dev,
+				   eth->base + MTK_ETH_PPE_BASE, 2);
+		if (err)
+			goto err_free_dev;
+	}
+
 	for (i = 0; i < MTK_MAX_DEVS; i++) {
 		if (!eth->netdev[i])
 			continue;
@@ -3129,6 +3144,7 @@ static const struct mtk_soc_data mt7621_data = {
 	.hw_features = MTK_HW_FEATURES,
 	.required_clks = MT7621_CLKS_BITMAP,
 	.required_pctl = false,
+	.offload_version = 2,
 };
 
 static const struct mtk_soc_data mt7622_data = {
@@ -3137,6 +3153,7 @@ static const struct mtk_soc_data mt7622_data = {
 	.hw_features = MTK_HW_FEATURES,
 	.required_clks = MT7622_CLKS_BITMAP,
 	.required_pctl = false,
+	.offload_version = 2,
 };
 
 static const struct mtk_soc_data mt7623_data = {

drivers/net/ethernet/mediatek/mtk_eth_soc.h

@@ -15,6 +15,7 @@
 #include <linux/u64_stats_sync.h>
 #include <linux/refcount.h>
 #include <linux/phylink.h>
+#include "mtk_ppe.h"
 
 #define MTK_QDMA_PAGE_SIZE	2048
 #define	MTK_MAX_RX_LENGTH	1536
@@ -85,6 +86,7 @@
 #define MTK_GDMA_TCS_EN		BIT(21)
 #define MTK_GDMA_UCS_EN		BIT(20)
 #define MTK_GDMA_TO_PDMA	0x0
+#define MTK_GDMA_TO_PPE		0x4444
 #define MTK_GDMA_DROP_ALL       0x7777
 
 /* Unicast Filter MAC Address Register - Low */
@@ -299,6 +301,12 @@
 /* QDMA descriptor rxd3 */
 #define RX_DMA_VID(_x)		((_x) & 0xfff)
 
+/* QDMA descriptor rxd4 */
+#define MTK_RXD4_FOE_ENTRY	GENMASK(13, 0)
+#define MTK_RXD4_PPE_CPU_REASON	GENMASK(18, 14)
+#define MTK_RXD4_SRC_PORT	GENMASK(21, 19)
+#define MTK_RXD4_ALG		GENMASK(31, 22)
+
 /* QDMA descriptor rxd4 */
 #define RX_DMA_L4_VALID		BIT(24)
 #define RX_DMA_L4_VALID_PDMA	BIT(30)		/* when PDMA is used */
@@ -796,6 +804,7 @@ struct mtk_soc_data {
 	u32		caps;
 	u32		required_clks;
 	bool		required_pctl;
+	u8		offload_version;
 	netdev_features_t hw_features;
 };
 
@@ -895,6 +904,8 @@ struct mtk_eth {
 	u32				tx_int_status_reg;
 	u32				rx_dma_l4_valid;
 	int				ip_align;
+
+	struct mtk_ppe			ppe;
 };
 
 /* struct mtk_mac -	the structure that holds the info about the MACs of the