bcm4908: add Ethernet driver

This commit picks up pending netdev patches.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

5 files changed, 1020 insertions, 0 deletions

diff --git a/target/linux/bcm4908/config-5.4 b/target/linux/bcm4908/config-5.4
index d13753c49d..2a3cd647fc 100644
--- a/target/linux/bcm4908/config-5.4
+++ b/target/linux/bcm4908/config-5.4
@@ -40,6 +40,7 @@ CONFIG_B53=y
 # CONFIG_B53_MMAP_DRIVER is not set
 # CONFIG_B53_SERDES is not set
 # CONFIG_B53_SRAB_DRIVER is not set
+CONFIG_BCM4908ENET=y
 CONFIG_BCM7XXX_PHY=y
 CONFIG_BCM_NET_PHYLIB=y
 CONFIG_BCM_PMB=y
diff --git a/target/linux/bcm4908/files-5.4/drivers/net/ethernet/broadcom/unimac.h b/target/linux/bcm4908/files-5.4/drivers/net/ethernet/broadcom/unimac.h
new file mode 100644
index 0000000000..585a852862
--- /dev/null
+++ b/target/linux/bcm4908/files-5.4/drivers/net/ethernet/broadcom/unimac.h
@@ -0,0 +1,68 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef __UNIMAC_H
+#define __UNIMAC_H
+
+#define UMAC_HD_BKP_CTRL		0x004
+#define  HD_FC_EN			(1 << 0)
+#define  HD_FC_BKOFF_OK			(1 << 1)
+#define  IPG_CONFIG_RX_SHIFT		2
+#define  IPG_CONFIG_RX_MASK		0x1F
+#define UMAC_CMD			0x008
+#define  CMD_TX_EN			(1 << 0)
+#define  CMD_RX_EN			(1 << 1)
+#define  CMD_SPEED_10			0
+#define  CMD_SPEED_100			1
+#define  CMD_SPEED_1000			2
+#define  CMD_SPEED_2500			3
+#define  CMD_SPEED_SHIFT		2
+#define  CMD_SPEED_MASK			3
+#define  CMD_PROMISC			(1 << 4)
+#define  CMD_PAD_EN			(1 << 5)
+#define  CMD_CRC_FWD			(1 << 6)
+#define  CMD_PAUSE_FWD			(1 << 7)
+#define  CMD_RX_PAUSE_IGNORE		(1 << 8)
+#define  CMD_TX_ADDR_INS		(1 << 9)
+#define  CMD_HD_EN			(1 << 10)
+#define  CMD_SW_RESET_OLD		(1 << 11)
+#define  CMD_SW_RESET			(1 << 13)
+#define  CMD_LCL_LOOP_EN		(1 << 15)
+#define  CMD_AUTO_CONFIG		(1 << 22)
+#define  CMD_CNTL_FRM_EN		(1 << 23)
+#define  CMD_NO_LEN_CHK			(1 << 24)
+#define  CMD_RMT_LOOP_EN		(1 << 25)
+#define  CMD_RX_ERR_DISC		(1 << 26)
+#define  CMD_PRBL_EN			(1 << 27)
+#define  CMD_TX_PAUSE_IGNORE		(1 << 28)
+#define  CMD_TX_RX_EN			(1 << 29)
+#define  CMD_RUNT_FILTER_DIS		(1 << 30)
+#define UMAC_MAC0			0x00c
+#define UMAC_MAC1			0x010
+#define UMAC_MAX_FRAME_LEN		0x014
+#define UMAC_PAUSE_QUANTA		0x018
+#define UMAC_MODE			0x044
+#define  MODE_LINK_STATUS		(1 << 5)
+#define UMAC_FRM_TAG0			0x048		/* outer tag */
+#define UMAC_FRM_TAG1			0x04c		/* inner tag */
+#define UMAC_TX_IPG_LEN			0x05c
+#define UMAC_EEE_CTRL			0x064
+#define  EN_LPI_RX_PAUSE		(1 << 0)
+#define  EN_LPI_TX_PFC			(1 << 1)
+#define  EN_LPI_TX_PAUSE		(1 << 2)
+#define  EEE_EN				(1 << 3)
+#define  RX_FIFO_CHECK			(1 << 4)
+#define  EEE_TX_CLK_DIS			(1 << 5)
+#define  DIS_EEE_10M			(1 << 6)
+#define  LP_IDLE_PREDICTION_MODE	(1 << 7)
+#define UMAC_EEE_LPI_TIMER		0x068
+#define UMAC_EEE_WAKE_TIMER		0x06C
+#define UMAC_EEE_REF_COUNT		0x070
+#define  EEE_REFERENCE_COUNT_MASK	0xffff
+#define UMAC_RX_IPG_INV			0x078
+#define UMAC_MACSEC_PROG_TX_CRC		0x310
+#define UMAC_MACSEC_CTRL		0x314
+#define UMAC_PAUSE_CTRL			0x330
+#define UMAC_TX_FLUSH			0x334
+#define UMAC_RX_FIFO_STATUS		0x338
+#define UMAC_TX_FIFO_STATUS		0x33c
+
+#endif
diff --git a/target/linux/bcm4908/patches-5.4/170-0001-dt-bindings-net-document-BCM4908-Ethernet-controller.patch b/target/linux/bcm4908/patches-5.4/170-0001-dt-bindings-net-document-BCM4908-Ethernet-controller.patch
new file mode 100644
index 0000000000..4c0f44199b
--- /dev/null
+++ b/target/linux/bcm4908/patches-5.4/170-0001-dt-bindings-net-document-BCM4908-Ethernet-controller.patch
@@ -0,0 +1,60 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Fri, 5 Feb 2021 21:57:41 +0100
+Subject: [PATCH 1/2] dt-bindings: net: document BCM4908 Ethernet controller
+
+BCM4908 is a family of SoCs with integrated Ethernet controller.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ .../bindings/net/brcm,bcm4908enet.yaml        | 45 +++++++++++++++++++
+ 1 file changed, 45 insertions(+)
+ create mode 100644 Documentation/devicetree/bindings/net/brcm,bcm4908enet.yaml
+
+--- /dev/null
++++ b/Documentation/devicetree/bindings/net/brcm,bcm4908enet.yaml
+@@ -0,0 +1,45 @@
++# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
++%YAML 1.2
++---
++$id: http://devicetree.org/schemas/net/brcm,bcm4908enet.yaml#
++$schema: http://devicetree.org/meta-schemas/core.yaml#
++
++title: Broadcom BCM4908 Ethernet controller
++
++description: Broadcom's Ethernet controller integrated into BCM4908 family SoCs
++
++maintainers:
++  - Rafał Miłecki <rafal@milecki.pl>
++
++properties:
++  compatible:
++    const: brcm,bcm4908enet
++
++  reg:
++    maxItems: 1
++
++  interrupts:
++    description: RX interrupt
++
++  interrupt-names:
++    const: rx
++
++required:
++  - reg
++  - interrupts
++  - interrupt-names
++
++additionalProperties: false
++
++examples:
++  - |
++    #include <dt-bindings/interrupt-controller/irq.h>
++    #include <dt-bindings/interrupt-controller/arm-gic.h>
++
++    ethernet@80002000 {
++        compatible = "brcm,bcm4908enet";
++        reg = <0x80002000 0x1000>;
++
++        interrupts = <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>;
++        interrupt-names = "rx";
++    };
diff --git a/target/linux/bcm4908/patches-5.4/170-0002-net-broadcom-bcm4908enet-add-BCM4908-controller-driv.patch b/target/linux/bcm4908/patches-5.4/170-0002-net-broadcom-bcm4908enet-add-BCM4908-controller-driv.patch
new file mode 100644
index 0000000000..5b2084e80c
--- /dev/null
+++ b/target/linux/bcm4908/patches-5.4/170-0002-net-broadcom-bcm4908enet-add-BCM4908-controller-driv.patch
@@ -0,0 +1,842 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Fri, 5 Feb 2021 21:59:51 +0100
+Subject: [PATCH 2/2] net: broadcom: bcm4908enet: add BCM4908 controller driver
+
+BCM4908 SoCs family uses Ethernel controller that includes UniMAC but
+uses different DMA engine (than other controllers) and requires
+different programming.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ MAINTAINERS                                 |   9 +
+ drivers/net/ethernet/broadcom/Kconfig       |   8 +
+ drivers/net/ethernet/broadcom/Makefile      |   1 +
+ drivers/net/ethernet/broadcom/bcm4908enet.c | 676 ++++++++++++++++++++
+ drivers/net/ethernet/broadcom/bcm4908enet.h |  96 +++
+ 5 files changed, 790 insertions(+)
+ create mode 100644 drivers/net/ethernet/broadcom/bcm4908enet.c
+ create mode 100644 drivers/net/ethernet/broadcom/bcm4908enet.h
+
+--- a/MAINTAINERS
++++ b/MAINTAINERS
+@@ -3207,6 +3207,15 @@ F:	Documentation/devicetree/bindings/mip
+ F:	arch/mips/bcm47xx/*
+ F:	arch/mips/include/asm/mach-bcm47xx/*
+ 
++BROADCOM BCM4908 ETHERNET DRIVER
++M:	Rafał Miłecki <rafal@milecki.pl>
++M:	bcm-kernel-feedback-list@broadcom.com
++L:	netdev@vger.kernel.org
++S:	Maintained
++F:	Documentation/devicetree/bindings/net/brcm,bcm4908enet.yaml
++F:	drivers/net/ethernet/broadcom/bcm4908enet.*
++F:	drivers/net/ethernet/broadcom/unimac.h
++
+ BROADCOM BCM5301X ARM ARCHITECTURE
+ M:	Hauke Mehrtens <hauke@hauke-m.de>
+ M:	Rafał Miłecki <zajec5@gmail.com>
+--- a/drivers/net/ethernet/broadcom/Kconfig
++++ b/drivers/net/ethernet/broadcom/Kconfig
+@@ -51,6 +51,14 @@ config B44_PCI
+ 	depends on B44_PCI_AUTOSELECT && B44_PCICORE_AUTOSELECT
+ 	default y
+ 
++config BCM4908ENET
++	tristate "Broadcom BCM4908 internal mac support"
++	depends on ARCH_BCM4908 || COMPILE_TEST
++	default y
++	help
++	  This driver supports Ethernet controller integrated into Broadcom
++	  BCM4908 family SoCs.
++
+ config BCM63XX_ENET
+ 	tristate "Broadcom 63xx internal mac support"
+ 	depends on BCM63XX
+--- a/drivers/net/ethernet/broadcom/Makefile
++++ b/drivers/net/ethernet/broadcom/Makefile
+@@ -4,6 +4,7 @@
+ #
+ 
+ obj-$(CONFIG_B44) += b44.o
++obj-$(CONFIG_BCM4908ENET) += bcm4908enet.o
+ obj-$(CONFIG_BCM63XX_ENET) += bcm63xx_enet.o
+ obj-$(CONFIG_BCMGENET) += genet/
+ obj-$(CONFIG_BNX2) += bnx2.o
+--- /dev/null
++++ b/drivers/net/ethernet/broadcom/bcm4908enet.c
+@@ -0,0 +1,676 @@
++// SPDX-License-Identifier: GPL-2.0-only
++/*
++ * Copyright (C) 2021 Rafał Miłecki <rafal@milecki.pl>
++ */
++
++#include <linux/delay.h>
++#include <linux/etherdevice.h>
++#include <linux/interrupt.h>
++#include <linux/module.h>
++#include <linux/of.h>
++#include <linux/platform_device.h>
++#include <linux/slab.h>
++#include <linux/string.h>
++
++#include "bcm4908enet.h"
++#include "unimac.h"
++
++#define ENET_DMA_CH_RX_CFG			ENET_DMA_CH0_CFG
++#define ENET_DMA_CH_TX_CFG			ENET_DMA_CH1_CFG
++#define ENET_DMA_CH_RX_STATE_RAM		ENET_DMA_CH0_STATE_RAM
++#define ENET_DMA_CH_TX_STATE_RAM		ENET_DMA_CH1_STATE_RAM
++
++#define ENET_TX_BDS_NUM				200
++#define ENET_RX_BDS_NUM				200
++#define ENET_RX_BDS_NUM_MAX			8192
++
++#define ENET_DMA_INT_DEFAULTS			(ENET_DMA_CH_CFG_INT_DONE | \
++						 ENET_DMA_CH_CFG_INT_NO_DESC | \
++						 ENET_DMA_CH_CFG_INT_BUFF_DONE)
++#define ENET_DMA_MAX_BURST_LEN			8 /* in 64 bit words */
++
++#define ENET_MTU_MIN				60
++#define ENET_MTU_MAX				1500 /* Is it possible to support 2044? */
++#define ENET_MTU_MAX_EXTRA_SIZE			32 /* L2 */
++
++struct bcm4908enet_dma_ring_bd {
++	__le32 ctl;
++	__le32 addr;
++} __packed;
++
++struct bcm4908enet_dma_ring_slot {
++	struct sk_buff *skb;
++	unsigned int len;
++	dma_addr_t dma_addr;
++};
++
++struct bcm4908enet_dma_ring {
++	int is_tx;
++	int read_idx;
++	int write_idx;
++	int length;
++	u16 cfg_block;
++	u16 st_ram_block;
++
++	union {
++		void *cpu_addr;
++		struct bcm4908enet_dma_ring_bd *buf_desc;
++	};
++	dma_addr_t dma_addr;
++
++	struct bcm4908enet_dma_ring_slot *slots;
++};
++
++struct bcm4908enet {
++	struct device *dev;
++	struct net_device *netdev;
++	struct napi_struct napi;
++	void __iomem *base;
++
++	struct bcm4908enet_dma_ring tx_ring;
++	struct bcm4908enet_dma_ring rx_ring;
++};
++
++/***
++ * R/W ops
++ */
++
++static inline u32 enet_read(struct bcm4908enet *enet, u16 offset)
++{
++	return readl(enet->base + offset);
++}
++
++static inline void enet_write(struct bcm4908enet *enet, u16 offset, u32 value)
++{
++	writel(value, enet->base + offset);
++}
++
++static inline void enet_maskset(struct bcm4908enet *enet, u16 offset, u32 mask, u32 set)
++{
++	u32 val;
++
++	WARN_ON(set & ~mask);
++
++	val = enet_read(enet, offset);
++	val = (val & ~mask) | (set & mask);
++	enet_write(enet, offset, val);
++}
++
++static inline void enet_set(struct bcm4908enet *enet, u16 offset, u32 set)
++{
++	enet_maskset(enet, offset, set, set);
++}
++
++static inline u32 enet_umac_read(struct bcm4908enet *enet, u16 offset)
++{
++	return enet_read(enet, ENET_UNIMAC + offset);
++}
++
++static inline void enet_umac_write(struct bcm4908enet *enet, u16 offset, u32 value)
++{
++	enet_write(enet, ENET_UNIMAC + offset, value);
++}
++
++static inline void enet_umac_maskset(struct bcm4908enet *enet, u16 offset, u32 mask, u32 set)
++{
++	enet_maskset(enet, ENET_UNIMAC + offset, mask, set);
++}
++
++static inline void enet_umac_set(struct bcm4908enet *enet, u16 offset, u32 set)
++{
++	enet_set(enet, ENET_UNIMAC + offset, set);
++}
++
++/***
++ * Helpers
++ */
++
++static void bcm4908enet_intrs_on(struct bcm4908enet *enet)
++{
++	enet_write(enet, ENET_DMA_CH_RX_CFG + ENET_DMA_CH_CFG_INT_MASK, ENET_DMA_INT_DEFAULTS);
++}
++
++static void bcm4908enet_intrs_off(struct bcm4908enet *enet)
++{
++	enet_write(enet, ENET_DMA_CH_RX_CFG + ENET_DMA_CH_CFG_INT_MASK, 0);
++}
++
++static void bcm4908enet_intrs_ack(struct bcm4908enet *enet)
++{
++	enet_write(enet, ENET_DMA_CH_RX_CFG + ENET_DMA_CH_CFG_INT_STAT, ENET_DMA_INT_DEFAULTS);
++}
++
++/***
++ * DMA
++ */
++
++static int bcm4908_dma_alloc_buf_descs(struct bcm4908enet *enet, struct bcm4908enet_dma_ring *ring)
++{
++	int size = ring->length * sizeof(struct bcm4908enet_dma_ring_bd);
++	struct device *dev = enet->dev;
++
++	ring->cpu_addr = dma_alloc_coherent(dev, size, &ring->dma_addr, GFP_KERNEL);
++	if (!ring->cpu_addr)
++		return -ENOMEM;
++
++	if (((uintptr_t)ring->cpu_addr) & (0x40 - 1)) {
++		dev_err(dev, "Invalid DMA ring alignment\n");
++		goto err_free_buf_descs;
++	}
++
++	ring->slots = kzalloc(ring->length * sizeof(*ring->slots), GFP_KERNEL);
++	if (!ring->slots)
++		goto err_free_buf_descs;
++
++	memset(ring->cpu_addr, 0, size);
++
++	ring->read_idx = 0;
++	ring->write_idx = 0;
++
++	return 0;
++
++err_free_buf_descs:
++	dma_free_coherent(dev, size, ring->cpu_addr, ring->dma_addr);
++	return -ENOMEM;
++}
++
++static void bcm4908enet_dma_free(struct bcm4908enet *enet)
++{
++	struct bcm4908enet_dma_ring *tx_ring = &enet->tx_ring;
++	struct bcm4908enet_dma_ring *rx_ring = &enet->rx_ring;
++	struct device *dev = enet->dev;
++	int size;
++
++	size = rx_ring->length * sizeof(struct bcm4908enet_dma_ring_bd);
++	if (rx_ring->cpu_addr)
++		dma_free_coherent(dev, size, rx_ring->cpu_addr, rx_ring->dma_addr);
++	kfree(rx_ring->slots);
++
++	size = tx_ring->length * sizeof(struct bcm4908enet_dma_ring_bd);
++	if (tx_ring->cpu_addr)
++		dma_free_coherent(dev, size, tx_ring->cpu_addr, tx_ring->dma_addr);
++	kfree(tx_ring->slots);
++}
++
++static int bcm4908enet_dma_alloc(struct bcm4908enet *enet)
++{
++	struct bcm4908enet_dma_ring *tx_ring = &enet->tx_ring;
++	struct bcm4908enet_dma_ring *rx_ring = &enet->rx_ring;
++	struct device *dev = enet->dev;
++	int err;
++
++	tx_ring->length = ENET_TX_BDS_NUM;
++	tx_ring->is_tx = 1;
++	tx_ring->cfg_block = ENET_DMA_CH_TX_CFG;
++	tx_ring->st_ram_block = ENET_DMA_CH_TX_STATE_RAM;
++	err = bcm4908_dma_alloc_buf_descs(enet, tx_ring);
++	if (err) {
++		dev_err(dev, "Failed to alloc TX buf descriptors: %d\n", err);
++		return err;
++	}
++
++	rx_ring->length = ENET_RX_BDS_NUM;
++	rx_ring->is_tx = 0;
++	rx_ring->cfg_block = ENET_DMA_CH_RX_CFG;
++	rx_ring->st_ram_block = ENET_DMA_CH_RX_STATE_RAM;
++	err = bcm4908_dma_alloc_buf_descs(enet, rx_ring);
++	if (err) {
++		dev_err(dev, "Failed to alloc RX buf descriptors: %d\n", err);
++		bcm4908enet_dma_free(enet);
++		return err;
++	}
++
++	return 0;
++}
++
++static void bcm4908enet_dma_reset(struct bcm4908enet *enet)
++{
++	struct bcm4908enet_dma_ring *rings[] = { &enet->rx_ring, &enet->tx_ring };
++	int i;
++
++	/* Disable the DMA controller and channel */
++	for (i = 0; i < ARRAY_SIZE(rings); i++)
++		enet_write(enet, rings[i]->cfg_block + ENET_DMA_CH_CFG, 0);
++	enet_maskset(enet, ENET_DMA_CONTROLLER_CFG, ENET_DMA_CTRL_CFG_MASTER_EN, 0);
++
++	/* Reset channels state */
++	for (i = 0; i < ARRAY_SIZE(rings); i++) {
++		struct bcm4908enet_dma_ring *ring = rings[i];
++
++		enet_write(enet, ring->st_ram_block + ENET_DMA_CH_STATE_RAM_BASE_DESC_PTR, 0);
++		enet_write(enet, ring->st_ram_block + ENET_DMA_CH_STATE_RAM_STATE_DATA, 0);
++		enet_write(enet, ring->st_ram_block + ENET_DMA_CH_STATE_RAM_DESC_LEN_STATUS, 0);
++		enet_write(enet, ring->st_ram_block + ENET_DMA_CH_STATE_RAM_DESC_BASE_BUFPTR, 0);
++	}
++}
++
++static int bcm4908enet_dma_alloc_rx_buf(struct bcm4908enet *enet, unsigned int idx)
++{
++	struct bcm4908enet_dma_ring_bd *buf_desc = &enet->rx_ring.buf_desc[idx];
++	struct bcm4908enet_dma_ring_slot *slot = &enet->rx_ring.slots[idx];
++	struct device *dev = enet->dev;
++	u32 tmp;
++	int err;
++
++	slot->len = ENET_MTU_MAX + ENET_MTU_MAX_EXTRA_SIZE;
++
++	slot->skb = netdev_alloc_skb(enet->netdev, slot->len);
++	if (!slot->skb)
++		return -ENOMEM;
++
++	slot->dma_addr = dma_map_single(dev, slot->skb->data, slot->len, DMA_FROM_DEVICE);
++	err = dma_mapping_error(dev, slot->dma_addr);
++	if (err) {
++		dev_err(dev, "Failed to map DMA buffer: %d\n", err);
++		kfree_skb(slot->skb);
++		slot->skb = NULL;
++		return err;
++	}
++
++	tmp = slot->len << DMA_CTL_LEN_DESC_BUFLENGTH_SHIFT;
++	tmp |= DMA_CTL_STATUS_OWN;
++	if (idx == enet->rx_ring.length - 1)
++		tmp |= DMA_CTL_STATUS_WRAP;
++	buf_desc->ctl = cpu_to_le32(tmp);
++	buf_desc->addr = cpu_to_le32(slot->dma_addr);
++
++	return 0;
++}
++
++static void bcm4908enet_dma_ring_init(struct bcm4908enet *enet,
++				      struct bcm4908enet_dma_ring *ring)
++{
++	int reset_channel = 0; /* We support only 1 main channel (with TX and RX) */
++	int reset_subch = ring->is_tx ? 1 : 0;
++
++	/* Reset the DMA channel */
++	enet_write(enet, ENET_DMA_CTRL_CHANNEL_RESET, BIT(reset_channel * 2 + reset_subch));
++	enet_write(enet, ENET_DMA_CTRL_CHANNEL_RESET, 0);
++
++	enet_write(enet, ring->cfg_block + ENET_DMA_CH_CFG, 0);
++	enet_write(enet, ring->cfg_block + ENET_DMA_CH_CFG_MAX_BURST, ENET_DMA_MAX_BURST_LEN);
++	enet_write(enet, ring->cfg_block + ENET_DMA_CH_CFG_INT_MASK, 0);
++
++	enet_write(enet, ring->st_ram_block + ENET_DMA_CH_STATE_RAM_BASE_DESC_PTR,
++		   (uint32_t)ring->dma_addr);
++}
++
++static void bcm4908enet_dma_uninit(struct bcm4908enet *enet)
++{
++	struct bcm4908enet_dma_ring *rx_ring = &enet->rx_ring;
++	struct bcm4908enet_dma_ring_slot *slot;
++	struct device *dev = enet->dev;
++	int i;
++
++	for (i = rx_ring->length - 1; i >= 0; i--) {
++		slot = &rx_ring->slots[i];
++		if (!slot->skb)
++			continue;
++		dma_unmap_single(dev, slot->dma_addr, slot->len, DMA_FROM_DEVICE);
++		kfree_skb(slot->skb);
++		slot->skb = NULL;
++	}
++}
++
++static int bcm4908enet_dma_init(struct bcm4908enet *enet)
++{
++	struct bcm4908enet_dma_ring *rx_ring = &enet->rx_ring;
++	struct device *dev = enet->dev;
++	int err;
++	int i;
++
++	for (i = 0; i < rx_ring->length; i++) {
++		err = bcm4908enet_dma_alloc_rx_buf(enet, i);
++		if (err) {
++			dev_err(dev, "Failed to alloc RX buffer: %d\n", err);
++			bcm4908enet_dma_uninit(enet);
++			return err;
++		}
++	}
++
++	bcm4908enet_dma_ring_init(enet, &enet->tx_ring);
++	bcm4908enet_dma_ring_init(enet, &enet->rx_ring);
++
++	return 0;
++}
++
++static void bcm4908enet_dma_tx_ring_ensable(struct bcm4908enet *enet,
++					    struct bcm4908enet_dma_ring *ring)
++{
++	enet_write(enet, ring->cfg_block + ENET_DMA_CH_CFG, ENET_DMA_CH_CFG_ENABLE);
++}
++
++static void bcm4908enet_dma_tx_ring_disable(struct bcm4908enet *enet,
++					    struct bcm4908enet_dma_ring *ring)
++{
++	enet_write(enet, ring->cfg_block + ENET_DMA_CH_CFG, 0);
++}
++
++static void bcm4908enet_dma_rx_ring_enable(struct bcm4908enet *enet,
++					   struct bcm4908enet_dma_ring *ring)
++{
++	enet_set(enet, ring->cfg_block + ENET_DMA_CH_CFG, ENET_DMA_CH_CFG_ENABLE);
++}
++
++static void bcm4908enet_dma_rx_ring_disable(struct bcm4908enet *enet,
++					    struct bcm4908enet_dma_ring *ring)
++{
++	unsigned long deadline;
++	u32 tmp;
++
++	enet_maskset(enet, ring->cfg_block + ENET_DMA_CH_CFG, ENET_DMA_CH_CFG_ENABLE, 0);
++
++	deadline = jiffies + usecs_to_jiffies(2000);
++	do {
++		tmp = enet_read(enet, ring->cfg_block + ENET_DMA_CH_CFG);
++		if (!(tmp & ENET_DMA_CH_CFG_ENABLE))
++			return;
++		enet_maskset(enet, ring->cfg_block + ENET_DMA_CH_CFG, ENET_DMA_CH_CFG_ENABLE, 0);
++		usleep_range(10, 30);
++	} while (!time_after_eq(jiffies, deadline));
++
++	dev_warn(enet->dev, "Timeout waiting for DMA TX stop\n");
++}
++
++/***
++ * Ethernet driver
++ */
++
++static void bcm4908enet_gmac_init(struct bcm4908enet *enet)
++{
++	u32 cmd;
++
++	cmd = enet_umac_read(enet, UMAC_CMD);
++	enet_umac_write(enet, UMAC_CMD, cmd | CMD_SW_RESET);
++	enet_umac_write(enet, UMAC_CMD, cmd & ~CMD_SW_RESET);
++
++	enet_set(enet, ENET_FLUSH, ENET_FLUSH_RXFIFO_FLUSH | ENET_FLUSH_TXFIFO_FLUSH);
++	enet_maskset(enet, ENET_FLUSH, ENET_FLUSH_RXFIFO_FLUSH | ENET_FLUSH_TXFIFO_FLUSH, 0);
++
++	enet_set(enet, ENET_MIB_CTRL, ENET_MIB_CTRL_CLR_MIB);
++	enet_maskset(enet, ENET_MIB_CTRL, ENET_MIB_CTRL_CLR_MIB, 0);
++
++	cmd = enet_umac_read(enet, UMAC_CMD);
++	cmd &= ~(CMD_SPEED_MASK << CMD_SPEED_SHIFT);
++	cmd &= ~CMD_TX_EN;
++	cmd &= ~CMD_RX_EN;
++	cmd |= CMD_SPEED_1000 << CMD_SPEED_SHIFT;
++	enet_umac_write(enet, UMAC_CMD, cmd);
++
++	enet_maskset(enet, ENET_GMAC_STATUS,
++		     ENET_GMAC_STATUS_ETH_SPEED_MASK |
++		     ENET_GMAC_STATUS_HD |
++		     ENET_GMAC_STATUS_AUTO_CFG_EN |
++		     ENET_GMAC_STATUS_LINK_UP,
++		     ENET_GMAC_STATUS_ETH_SPEED_1000 |
++		     ENET_GMAC_STATUS_AUTO_CFG_EN |
++		     ENET_GMAC_STATUS_LINK_UP);
++}
++
++static irqreturn_t bcm4908enet_irq_handler(int irq, void *dev_id)
++{
++	struct bcm4908enet *enet = dev_id;
++
++	bcm4908enet_intrs_off(enet);
++	bcm4908enet_intrs_ack(enet);
++
++	napi_schedule(&enet->napi);
++
++	return IRQ_HANDLED;
++}
++
++static int bcm4908enet_open(struct net_device *netdev)
++{
++	struct bcm4908enet *enet = netdev_priv(netdev);
++	struct device *dev = enet->dev;
++	int err;
++
++	err = request_irq(netdev->irq, bcm4908enet_irq_handler, 0, "enet", enet);
++	if (err) {
++		dev_err(dev, "Failed to request IRQ %d: %d\n", netdev->irq, err);
++		return err;
++	}
++
++	bcm4908enet_gmac_init(enet);
++	bcm4908enet_dma_reset(enet);
++	bcm4908enet_dma_init(enet);
++
++	enet_umac_set(enet, UMAC_CMD, CMD_TX_EN | CMD_RX_EN);
++
++	enet_set(enet, ENET_DMA_CONTROLLER_CFG, ENET_DMA_CTRL_CFG_MASTER_EN);
++	enet_maskset(enet, ENET_DMA_CONTROLLER_CFG, ENET_DMA_CTRL_CFG_FLOWC_CH1_EN, 0);
++	bcm4908enet_dma_rx_ring_enable(enet, &enet->rx_ring);
++
++	napi_enable(&enet->napi);
++	netif_carrier_on(netdev);
++	netif_start_queue(netdev);
++
++	bcm4908enet_intrs_ack(enet);
++	bcm4908enet_intrs_on(enet);
++
++	return 0;
++}
++
++static int bcm4908enet_stop(struct net_device *netdev)
++{
++	struct bcm4908enet *enet = netdev_priv(netdev);
++
++	netif_stop_queue(netdev);
++	netif_carrier_off(netdev);
++	napi_disable(&enet->napi);
++
++	bcm4908enet_dma_rx_ring_disable(enet, &enet->rx_ring);
++	bcm4908enet_dma_tx_ring_disable(enet, &enet->tx_ring);
++
++	bcm4908enet_dma_uninit(enet);
++
++	free_irq(enet->netdev->irq, enet);
++
++	return 0;
++}
++
++static int bcm4908enet_start_xmit(struct sk_buff *skb, struct net_device *netdev)
++{
++	struct bcm4908enet *enet = netdev_priv(netdev);
++	struct bcm4908enet_dma_ring *ring = &enet->tx_ring;
++	struct bcm4908enet_dma_ring_slot *slot;
++	struct device *dev = enet->dev;
++	struct bcm4908enet_dma_ring_bd *buf_desc;
++	int free_buf_descs;
++	u32 tmp;
++
++	/* Free transmitted skbs */
++	while (ring->read_idx != ring->write_idx) {
++		buf_desc = &ring->buf_desc[ring->read_idx];
++		if (buf_desc->ctl & DMA_CTL_STATUS_OWN)
++			break;
++		slot = &ring->slots[ring->read_idx];
++
++		dma_unmap_single(dev, slot->dma_addr, slot->len, DMA_TO_DEVICE);
++		dev_kfree_skb(slot->skb);
++		if (++ring->read_idx == ring->length)
++			ring->read_idx = 0;
++	}
++
++	/* Don't use the last empty buf descriptor */
++	if (ring->read_idx <= ring->write_idx)
++		free_buf_descs = ring->read_idx - ring->write_idx + ring->length;
++	else
++		free_buf_descs = ring->read_idx - ring->write_idx;
++	if (free_buf_descs < 2)
++		return NETDEV_TX_BUSY;
++
++	/* Hardware removes OWN bit after sending data */
++	buf_desc = &ring->buf_desc[ring->write_idx];
++	if (unlikely(le32_to_cpu(buf_desc->ctl) & DMA_CTL_STATUS_OWN)) {
++		netif_stop_queue(netdev);
++		return NETDEV_TX_BUSY;
++	}
++
++	slot = &ring->slots[ring->write_idx];
++	slot->skb = skb;
++	slot->len = skb->len;
++	slot->dma_addr = dma_map_single(dev, skb->data, skb->len, DMA_TO_DEVICE);
++	if (unlikely(dma_mapping_error(dev, slot->dma_addr)))
++		return NETDEV_TX_BUSY;
++
++	tmp = skb->len << DMA_CTL_LEN_DESC_BUFLENGTH_SHIFT;
++	tmp |= DMA_CTL_STATUS_OWN;
++	tmp |= DMA_CTL_STATUS_SOP;
++	tmp |= DMA_CTL_STATUS_EOP;
++	tmp |= DMA_CTL_STATUS_APPEND_CRC;
++	if (ring->write_idx + 1 == ring->length - 1)
++		tmp |= DMA_CTL_STATUS_WRAP;
++
++	buf_desc->addr = cpu_to_le32((uint32_t)slot->dma_addr);
++	buf_desc->ctl = cpu_to_le32(tmp);
++
++	bcm4908enet_dma_tx_ring_ensable(enet, &enet->tx_ring);
++
++	if (++ring->write_idx == ring->length - 1)
++		ring->write_idx = 0;
++	enet->netdev->stats.tx_bytes += skb->len;
++	enet->netdev->stats.tx_packets++;
++
++	return NETDEV_TX_OK;
++}
++
++static int bcm4908enet_poll(struct napi_struct *napi, int weight)
++{
++	struct bcm4908enet *enet = container_of(napi, struct bcm4908enet, napi);
++	struct device *dev = enet->dev;
++	int handled = 0;
++
++	while (handled < weight) {
++		struct bcm4908enet_dma_ring_bd *buf_desc;
++		struct bcm4908enet_dma_ring_slot slot;
++		u32 ctl;
++		int len;
++		int err;
++
++		buf_desc = &enet->rx_ring.buf_desc[enet->rx_ring.read_idx];
++		ctl = le32_to_cpu(buf_desc->ctl);
++		if (ctl & DMA_CTL_STATUS_OWN)
++			break;
++
++		slot = enet->rx_ring.slots[enet->rx_ring.read_idx];
++
++		/* Provide new buffer before unpinning the old one */
++		err = bcm4908enet_dma_alloc_rx_buf(enet, enet->rx_ring.read_idx);
++		if (err)
++			break;
++
++		if (++enet->rx_ring.read_idx == enet->rx_ring.length)
++			enet->rx_ring.read_idx = 0;
++
++		len = (ctl & DMA_CTL_LEN_DESC_BUFLENGTH) >> DMA_CTL_LEN_DESC_BUFLENGTH_SHIFT;
++
++		if (len < ENET_MTU_MIN ||
++		    (ctl & (DMA_CTL_STATUS_SOP | DMA_CTL_STATUS_EOP)) != (DMA_CTL_STATUS_SOP | DMA_CTL_STATUS_EOP)) {
++			enet->netdev->stats.rx_dropped++;
++			break;
++		}
++
++		dma_unmap_single(dev, slot.dma_addr, slot.len, DMA_FROM_DEVICE);
++
++		skb_put(slot.skb, len - 4 + 2);
++		slot.skb->protocol = eth_type_trans(slot.skb, enet->netdev);
++		netif_receive_skb(slot.skb);
++
++		enet->netdev->stats.rx_packets++;
++		enet->netdev->stats.rx_bytes += len;
++	}
++
++	if (handled < weight) {
++		napi_complete_done(napi, handled);
++		bcm4908enet_intrs_on(enet);
++	}
++
++	return handled;
++}
++
++static const struct net_device_ops bcm96xx_netdev_ops = {
++	.ndo_open = bcm4908enet_open,
++	.ndo_stop = bcm4908enet_stop,
++	.ndo_start_xmit = bcm4908enet_start_xmit,
++	.ndo_set_mac_address = eth_mac_addr,
++};
++
++static int bcm4908enet_probe(struct platform_device *pdev)
++{
++	struct device *dev = &pdev->dev;
++	struct net_device *netdev;
++	struct bcm4908enet *enet;
++	int err;
++
++	netdev = devm_alloc_etherdev(dev, sizeof(*enet));
++	if (!netdev)
++		return -ENOMEM;
++
++	enet = netdev_priv(netdev);
++	enet->dev = dev;
++	enet->netdev = netdev;
++
++	enet->base = devm_platform_ioremap_resource(pdev, 0);
++	if (IS_ERR(enet->base)) {
++		dev_err(dev, "Failed to map registers: %ld\n", PTR_ERR(enet->base));
++		return PTR_ERR(enet->base);
++	}
++
++	netdev->irq = platform_get_irq_byname(pdev, "rx");
++	if (netdev->irq < 0)
++		return netdev->irq;
++
++	dma_set_coherent_mask(dev, DMA_BIT_MASK(32));
++
++	err = bcm4908enet_dma_alloc(enet);
++	if (err)
++		return err;
++
++	SET_NETDEV_DEV(netdev, &pdev->dev);
++	eth_hw_addr_random(netdev);
++	netdev->netdev_ops = &bcm96xx_netdev_ops;
++	netdev->min_mtu = ETH_ZLEN;
++	netdev->mtu = ENET_MTU_MAX;
++	netdev->max_mtu = ENET_MTU_MAX;
++	netif_napi_add(netdev, &enet->napi, bcm4908enet_poll, 64);
++
++	err = register_netdev(netdev);
++	if (err) {
++		bcm4908enet_dma_free(enet);
++		return err;
++	}
++
++	platform_set_drvdata(pdev, enet);
++
++	return 0;
++}
++
++static int bcm4908enet_remove(struct platform_device *pdev)
++{
++	struct bcm4908enet *enet = platform_get_drvdata(pdev);
++
++	unregister_netdev(enet->netdev);
++	netif_napi_del(&enet->napi);
++	bcm4908enet_dma_free(enet);
++
++	return 0;
++}
++
++static const struct of_device_id bcm4908enet_of_match[] = {
++	{ .compatible = "brcm,bcm4908enet"},
++	{},
++};
++
++static struct platform_driver bcm4908enet_driver = {
++	.driver = {
++		.name = "bcm4908enet",
++		.of_match_table = bcm4908enet_of_match,
++	},
++	.probe	= bcm4908enet_probe,
++	.remove = bcm4908enet_remove,
++};
++module_platform_driver(bcm4908enet_driver);
++
++MODULE_LICENSE("GPL v2");
++MODULE_DEVICE_TABLE(of, bcm4908enet_of_match);
+--- /dev/null
++++ b/drivers/net/ethernet/broadcom/bcm4908enet.h
+@@ -0,0 +1,96 @@
++/* SPDX-License-Identifier: GPL-2.0-only */
++#ifndef __BCM4908ENET_H
++#define __BCM4908ENET_H
++
++#define ENET_CONTROL					0x000
++#define ENET_MIB_CTRL					0x004
++#define  ENET_MIB_CTRL_CLR_MIB				0x00000001
++#define ENET_RX_ERR_MASK				0x008
++#define ENET_MIB_MAX_PKT_SIZE				0x00C
++#define  ENET_MIB_MAX_PKT_SIZE_VAL			0x00003fff
++#define ENET_DIAG_OUT					0x01c
++#define ENET_ENABLE_DROP_PKT				0x020
++#define ENET_IRQ_ENABLE					0x024
++#define  ENET_IRQ_ENABLE_OVFL				0x00000001
++#define ENET_GMAC_STATUS				0x028
++#define  ENET_GMAC_STATUS_ETH_SPEED_MASK		0x00000003
++#define  ENET_GMAC_STATUS_ETH_SPEED_10			0x00000000
++#define  ENET_GMAC_STATUS_ETH_SPEED_100			0x00000001
++#define  ENET_GMAC_STATUS_ETH_SPEED_1000		0x00000002
++#define  ENET_GMAC_STATUS_HD				0x00000004
++#define  ENET_GMAC_STATUS_AUTO_CFG_EN			0x00000008
++#define  ENET_GMAC_STATUS_LINK_UP			0x00000010
++#define ENET_IRQ_STATUS					0x02c
++#define  ENET_IRQ_STATUS_OVFL				0x00000001
++#define ENET_OVERFLOW_COUNTER				0x030
++#define ENET_FLUSH					0x034
++#define  ENET_FLUSH_RXFIFO_FLUSH			0x00000001
++#define  ENET_FLUSH_TXFIFO_FLUSH			0x00000002
++#define ENET_RSV_SELECT					0x038
++#define ENET_BP_FORCE					0x03c
++#define  ENET_BP_FORCE_FORCE				0x00000001
++#define ENET_DMA_RX_OK_TO_SEND_COUNT			0x040
++#define  ENET_DMA_RX_OK_TO_SEND_COUNT_VAL		0x0000000f
++#define ENET_TX_CRC_CTRL				0x044
++#define ENET_MIB					0x200
++#define ENET_UNIMAC					0x400
++#define ENET_DMA					0x800
++#define ENET_DMA_CONTROLLER_CFG				0x800
++#define  ENET_DMA_CTRL_CFG_MASTER_EN			0x00000001
++#define  ENET_DMA_CTRL_CFG_FLOWC_CH1_EN			0x00000002
++#define  ENET_DMA_CTRL_CFG_FLOWC_CH3_EN			0x00000004
++#define ENET_DMA_FLOWCTL_CH1_THRESH_LO			0x804
++#define ENET_DMA_FLOWCTL_CH1_THRESH_HI			0x808
++#define ENET_DMA_FLOWCTL_CH1_ALLOC			0x80c
++#define  ENET_DMA_FLOWCTL_CH1_ALLOC_FORCE		0x80000000
++#define ENET_DMA_FLOWCTL_CH3_THRESH_LO			0x810
++#define ENET_DMA_FLOWCTL_CH3_THRESH_HI			0x814
++#define ENET_DMA_FLOWCTL_CH3_ALLOC			0x818
++#define ENET_DMA_FLOWCTL_CH5_THRESH_LO			0x81C
++#define ENET_DMA_FLOWCTL_CH5_THRESH_HI			0x820
++#define ENET_DMA_FLOWCTL_CH5_ALLOC			0x824
++#define ENET_DMA_FLOWCTL_CH7_THRESH_LO			0x828
++#define ENET_DMA_FLOWCTL_CH7_THRESH_HI			0x82C
++#define ENET_DMA_FLOWCTL_CH7_ALLOC			0x830
++#define ENET_DMA_CTRL_CHANNEL_RESET			0x834
++#define ENET_DMA_CTRL_CHANNEL_DEBUG			0x838
++#define ENET_DMA_CTRL_GLOBAL_INTERRUPT_STATUS		0x840
++#define ENET_DMA_CTRL_GLOBAL_INTERRUPT_MASK		0x844
++#define ENET_DMA_CH0_CFG				0xa00		/* RX */
++#define ENET_DMA_CH1_CFG				0xa10		/* TX */
++#define ENET_DMA_CH0_STATE_RAM				0xc00		/* RX */
++#define ENET_DMA_CH1_STATE_RAM				0xc10		/* TX */
++
++#define ENET_DMA_CH_CFG					0x00		/* assorted configuration */
++#define  ENET_DMA_CH_CFG_ENABLE				0x00000001	/* set to enable channel */
++#define  ENET_DMA_CH_CFG_PKT_HALT			0x00000002	/* idle after an EOP flag is detected */
++#define  ENET_DMA_CH_CFG_BURST_HALT			0x00000004	/* idle after finish current memory burst */
++#define ENET_DMA_CH_CFG_INT_STAT			0x04		/* interrupts control and status */
++#define ENET_DMA_CH_CFG_INT_MASK			0x08		/* interrupts mask */
++#define  ENET_DMA_CH_CFG_INT_BUFF_DONE			0x00000001	/* buffer done */
++#define  ENET_DMA_CH_CFG_INT_DONE			0x00000002	/* packet xfer complete */
++#define  ENET_DMA_CH_CFG_INT_NO_DESC			0x00000004	/* no valid descriptors */
++#define  ENET_DMA_CH_CFG_INT_RX_ERROR			0x00000008	/* rxdma detect client protocol error */
++#define ENET_DMA_CH_CFG_MAX_BURST			0x0c		/* max burst length permitted */
++#define  ENET_DMA_CH_CFG_MAX_BURST_DESCSIZE_SEL		0x00040000	/* DMA Descriptor Size Selection */
++#define ENET_DMA_CH_CFG_SIZE				0x10
++
++#define ENET_DMA_CH_STATE_RAM_BASE_DESC_PTR		0x00		/* descriptor ring start address */
++#define ENET_DMA_CH_STATE_RAM_STATE_DATA		0x04		/* state/bytes done/ring offset */
++#define ENET_DMA_CH_STATE_RAM_DESC_LEN_STATUS		0x08		/* buffer descriptor status and len */
++#define ENET_DMA_CH_STATE_RAM_DESC_BASE_BUFPTR		0x0c		/* buffer descrpitor current processing */
++#define ENET_DMA_CH_STATE_RAM_SIZE			0x10
++
++#define DMA_CTL_STATUS_APPEND_CRC			0x00000100
++#define DMA_CTL_STATUS_APPEND_BRCM_TAG			0x00000200
++#define DMA_CTL_STATUS_PRIO				0x00000C00  /* Prio for Tx */
++#define DMA_CTL_STATUS_WRAP				0x00001000  /* */
++#define DMA_CTL_STATUS_SOP				0x00002000  /* first buffer in packet */
++#define DMA_CTL_STATUS_EOP				0x00004000  /* last buffer in packet */
++#define DMA_CTL_STATUS_OWN				0x00008000  /* cleared by DMA, set by SW */
++#define DMA_CTL_LEN_DESC_BUFLENGTH			0x0fff0000
++#define DMA_CTL_LEN_DESC_BUFLENGTH_SHIFT		16
++#define DMA_CTL_LEN_DESC_MULTICAST			0x40000000
++#define DMA_CTL_LEN_DESC_USEFPM				0x80000000
++
++#endif
diff --git a/target/linux/bcm4908/patches-5.4/302-arm64-dts-broadcom-bcm4908-describe-Ethernet-control.patch b/target/linux/bcm4908/patches-5.4/302-arm64-dts-broadcom-bcm4908-describe-Ethernet-control.patch
new file mode 100644
index 0000000000..755292dacf
--- /dev/null
+++ b/target/linux/bcm4908/patches-5.4/302-arm64-dts-broadcom-bcm4908-describe-Ethernet-control.patch
@@ -0,0 +1,49 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Date: Mon, 8 Feb 2021 09:11:36 +0100
+Subject: [PATCH] arm64: dts: broadcom: bcm4908: describe Ethernet controller
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+BCM4908 SoCs have an integrated Ethernet controller.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+
+--- a/arch/arm64/boot/dts/broadcom/bcm4908/bcm4908-asus-gt-ac5300.dts
++++ b/arch/arm64/boot/dts/broadcom/bcm4908/bcm4908-asus-gt-ac5300.dts
+@@ -87,6 +87,17 @@
+ 			full-duplex;
+ 		};
+ 	};
++
++	port@8 {
++		reg = <8>;
++		phy-mode = "internal";
++		brcm,use-bcm-hdr;
++		ethernet = <&gmac>;
++		fixed-link {
++			speed = <1000>;
++			full-duplex;
++		};
++	};
+ };
+ 
+ &mdio {
+--- a/arch/arm64/boot/dts/broadcom/bcm4908/bcm4908.dtsi
++++ b/arch/arm64/boot/dts/broadcom/bcm4908/bcm4908.dtsi
+@@ -112,6 +112,14 @@
+ 		#size-cells = <1>;
+ 		ranges = <0x00 0x00 0x80000000 0x281000>;
+ 
++		gmac: ethernet@2000 {
++			compatible = "brcm,bcm4908enet";
++			reg = <0x2000 0x1000>;
++
++			interrupts = <GIC_SPI 86 IRQ_TYPE_LEVEL_HIGH>;
++			interrupt-names = "rx";
++		};
++
+ 		usb_phy: usb-phy@c200 {
+ 			compatible = "brcm,bcm4908-usb-phy";
+ 			reg = <0xc200 0x100>;