Merge branch 'mediatek-add-support-for-MediaTek-Ethernet-MAC'

Bartosz Golaszewski says:

====================
mediatek: add support for MediaTek Ethernet MAC

This series adds support for the STAR Ethernet Controller present on MediaTeK
SoCs from the MT8* family.

First we convert the existing DT bindings for the PERICFG controller to YAML
and add a new compatible string for mt8516 variant of it. Then we add the DT
bindings for the MAC.

Next we do some cleanup of the mediatek ethernet drivers directory.

The largest patch in the series adds the actual new driver.

The rest of the patches add DT fixups for the boards already supported
upstream.

v1 -> v2:
- add a generic helper for retrieving the net_device associated with given
  private data
- fix several typos in commit messages
- remove MTK_MAC_VERSION and don't set the driver version
- use NET_IP_ALIGN instead of a magic number (2) but redefine it as it defaults
  to 0 on arm64
- don't manually turn the carrier off in mtk_mac_enable()
- process TX cleanup in napi poll callback
- configure pause in the adjust_link callback
- use regmap_read_poll_timeout() instead of handcoding the polling
- use devres_find() to verify that struct net_device is managed by devres in
  devm_register_netdev()
- add a patch moving all networking devres helpers into net/devres.c
- tweak the dma barriers: remove where unnecessary and add comments to the
  remaining barriers
- don't reset internal counters when enabling the NIC
- set the net_device's mtu size instead of checking the framesize in
  ndo_start_xmit() callback
- fix a race condition in waking up the netif queue
- don't emit log messages on OOM errors
- use dma_set_mask_and_coherent()
- use eth_hw_addr_random()
- rework the receive callback so that we reuse the previous skb if unmapping
  fails, like we already do if skb allocation fails
- rework hash table operations: add proper timeout handling and clear bits when
  appropriate

v2 -> v3:
- drop the patch adding priv_to_netdev() and store the netdev pointer in the
  driver private data
- add an additional dma_wmb() after reseting the descriptor in
  mtk_mac_ring_pop_tail()
- check the return value of dma_set_mask_and_coherent()
- improve the DT bindings for mtk-eth-mac: make the reg property in the example
  use single-cell address and size, extend the description of the PERICFG
  phandle and document the mdio sub-node
- add a patch converting the old .txt bindings for PERICFG to yaml
- limit reading the DMA memory by storing the mapped addresses in the driver
  private structure
- add a patch documenting the existing networking devres helpers

v3 -> v4:
- drop the devres patches: they will be sent separately
- call netdev_sent_queue() & netdev_completed_queue() where appropriate
- don't redefine NET_IP_ALIGN: define a private constant in the driver
- fix a couple typos
- only disabe/enable the MAC in suspend/resume if netif is running
- drop the count field from the ring structure and instead calculate the number
  of used descriptors from the tail and head indicies
- rework the locking used to protect the ring structures from concurrent
  access: use cheaper spin_lock_bh() and completely disable the internal
  spinlock used by regmap
- rework the interrupt handling to make it more fine-grained: onle re-enable
  TX and RX interrupts while they're needed, process the stats updates in a
  workqueue, not in napi context
- shrink the code responsible for unmapping and freeing skb memory
- rework the barriers as advised by Arnd

v4 -> v5:
- rename the driver to make it less confusing with the existing mtk_eth_soc
  ethernet driver
- unregister the mdiobus at device's detachment
- open-code spin lock calls to avoid calling the _bh variants where unnecessary
- limit read-modify-write operations where possible when accessing descriptor
  memory
- use READ_ONCE/WRITE_ONCE when modifying the status and data_ptr descriptor
  fields
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

8 files changed, 1892 insertions, 38 deletions

diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.txt b/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.txt
deleted file mode 100644
index ecf027a9003a..000000000000
--- a/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.txt
+++ /dev/null
@@ -1,36 +0,0 @@
-Mediatek pericfg controller
-===========================
-
-The Mediatek pericfg controller provides various clocks and reset
-outputs to the system.
-
-Required Properties:
-
-- compatible: Should be one of:
-	- "mediatek,mt2701-pericfg", "syscon"
-	- "mediatek,mt2712-pericfg", "syscon"
-	- "mediatek,mt7622-pericfg", "syscon"
-	- "mediatek,mt7623-pericfg", "mediatek,mt2701-pericfg", "syscon"
-	- "mediatek,mt7629-pericfg", "syscon"
-	- "mediatek,mt8135-pericfg", "syscon"
-	- "mediatek,mt8173-pericfg", "syscon"
-	- "mediatek,mt8183-pericfg", "syscon"
-- #clock-cells: Must be 1
-- #reset-cells: Must be 1
-
-The pericfg controller uses the common clk binding from
-Documentation/devicetree/bindings/clock/clock-bindings.txt
-The available clocks are defined in dt-bindings/clock/mt*-clk.h.
-Also it uses the common reset controller binding from
-Documentation/devicetree/bindings/reset/reset.txt.
-The available reset outputs are defined in
-dt-bindings/reset/mt*-resets.h
-
-Example:
-
-pericfg: power-controller@10003000 {
-	compatible = "mediatek,mt8173-pericfg", "syscon";
-	reg = <0 0x10003000 0 0x1000>;
-	#clock-cells = <1>;
-	#reset-cells = <1>;
-};
diff --git a/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.yaml b/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.yaml
new file mode 100644
index 000000000000..55209a2baedc
--- /dev/null
+++ b/Documentation/devicetree/bindings/arm/mediatek/mediatek,pericfg.yaml
@@ -0,0 +1,64 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/arm/mediatek/mediatek,pericfg.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: MediaTek Peripheral Configuration Controller
+
+maintainers:
+  - Bartosz Golaszewski <bgolaszewski@baylibre.com>
+
+description:
+  The Mediatek pericfg controller provides various clocks and reset outputs
+  to the system.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+        - enum:
+          - mediatek,mt2701-pericfg
+          - mediatek,mt2712-pericfg
+          - mediatek,mt7622-pericfg
+          - mediatek,mt7629-pericfg
+          - mediatek,mt8135-pericfg
+          - mediatek,mt8173-pericfg
+          - mediatek,mt8183-pericfg
+          - mediatek,mt8516-pericfg
+        - const: syscon
+      - items:
+        # Special case for mt7623 for backward compatibility
+        - const: mediatek,mt7623-pericfg
+        - const: mediatek,mt2701-pericfg
+        - const: syscon
+
+  reg:
+    maxItems: 1
+
+  '#clock-cells':
+    const: 1
+
+  '#reset-cells':
+    const: 1
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    pericfg@10003000 {
+        compatible = "mediatek,mt8173-pericfg", "syscon";
+        reg = <0x10003000 0x1000>;
+        #clock-cells = <1>;
+        #reset-cells = <1>;
+    };
+
+  - |
+    pericfg@10003000 {
+        compatible =  "mediatek,mt7623-pericfg", "mediatek,mt2701-pericfg", "syscon";
+        reg = <0x10003000 0x1000>;
+        #clock-cells = <1>;
+        #reset-cells = <1>;
+    };
diff --git a/Documentation/devicetree/bindings/net/mediatek,eth-mac.yaml b/Documentation/devicetree/bindings/net/mediatek,eth-mac.yaml
new file mode 100644
index 000000000000..f85d91a9d6e5
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/mediatek,eth-mac.yaml
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/mediatek,eth-mac.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: MediaTek STAR Ethernet MAC Controller
+
+maintainers:
+  - Bartosz Golaszewski <bgolaszewski@baylibre.com>
+
+description:
+  This Ethernet MAC is used on the MT8* family of SoCs from MediaTek.
+  It's compliant with 802.3 standards and supports half- and full-duplex
+  modes with flow-control as well as CRC offloading and VLAN tags.
+
+allOf:
+  - $ref: "ethernet-controller.yaml#"
+
+properties:
+  compatible:
+    enum:
+      - mediatek,mt8516-eth
+      - mediatek,mt8518-eth
+      - mediatek,mt8175-eth
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    minItems: 3
+    maxItems: 3
+
+  clock-names:
+    additionalItems: false
+    items:
+      - const: core
+      - const: reg
+      - const: trans
+
+  mediatek,pericfg:
+    $ref: /schemas/types.yaml#definitions/phandle
+    description:
+      Phandle to the device containing the PERICFG register range. This is used
+      to control the MII mode.
+
+  mdio:
+    type: object
+    description:
+      Creates and registers an MDIO bus.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+  - clock-names
+  - mediatek,pericfg
+  - phy-handle
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/clock/mt8516-clk.h>
+
+    ethernet: ethernet@11180000 {
+        compatible = "mediatek,mt8516-eth";
+        reg = <0x11180000 0x1000>;
+        mediatek,pericfg = <&pericfg>;
+        interrupts = <GIC_SPI 111 IRQ_TYPE_LEVEL_LOW>;
+        clocks = <&topckgen CLK_TOP_RG_ETH>,
+                 <&topckgen CLK_TOP_66M_ETH>,
+                 <&topckgen CLK_TOP_133M_ETH>;
+        clock-names = "core", "reg", "trans";
+        phy-handle = <&eth_phy>;
+        phy-mode = "rmii";
+
+        mdio {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            eth_phy: ethernet-phy@0 {
+                reg = <0>;
+            };
+        };
+    };
diff --git a/arch/arm64/boot/dts/mediatek/mt8516.dtsi b/arch/arm64/boot/dts/mediatek/mt8516.dtsi
index 2f8adf042195..89af661e7f63 100644
--- a/arch/arm64/boot/dts/mediatek/mt8516.dtsi
+++ b/arch/arm64/boot/dts/mediatek/mt8516.dtsi
@@ -191,6 +191,11 @@
 			#clock-cells = <1>;
 		};
 
+		pericfg: pericfg@10003050 {
+			compatible = "mediatek,mt8516-pericfg", "syscon";
+			reg = <0 0x10003050 0 0x1000>;
+		};
+
 		apmixedsys: apmixedsys@10018000 {
 			compatible = "mediatek,mt8516-apmixedsys", "syscon";
 			reg = <0 0x10018000 0 0x710>;
@@ -401,6 +406,18 @@
 			status = "disabled";
 		};
 
+		ethernet: ethernet@11180000 {
+			compatible = "mediatek,mt8516-eth";
+			reg = <0 0x11180000 0 0x1000>;
+			mediatek,pericfg = <&pericfg>;
+			interrupts = <GIC_SPI 111 IRQ_TYPE_LEVEL_LOW>;
+			clocks = <&topckgen CLK_TOP_RG_ETH>,
+				 <&topckgen CLK_TOP_66M_ETH>,
+				 <&topckgen CLK_TOP_133M_ETH>;
+			clock-names = "core", "reg", "trans";
+			status = "disabled";
+		};
+
 		rng: rng@1020c000 {
 			compatible = "mediatek,mt8516-rng",
 				     "mediatek,mt7623-rng";
diff --git a/arch/arm64/boot/dts/mediatek/pumpkin-common.dtsi b/arch/arm64/boot/dts/mediatek/pumpkin-common.dtsi
index a31093d7142b..dfceffe6950a 100644
--- a/arch/arm64/boot/dts/mediatek/pumpkin-common.dtsi
+++ b/arch/arm64/boot/dts/mediatek/pumpkin-common.dtsi
@@ -9,6 +9,7 @@
 / {
 	aliases {
 		serial0 = &uart0;
+		ethernet0 = &ethernet;
 	};
 
 	chosen {
@@ -166,6 +167,24 @@
 	status = "okay";
 };
 
+&ethernet {
+	pinctrl-names = "default";
+	pinctrl-0 = <&ethernet_pins_default>;
+	phy-handle = <&eth_phy>;
+	phy-mode = "rmii";
+	mac-address = [00 00 00 00 00 00];
+	status = "okay";
+
+	mdio {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		eth_phy: ethernet-phy@0 {
+			reg = <0>;
+		};
+	};
+};
+
 &usb0 {
 	status = "okay";
 	dr_mode = "peripheral";
@@ -218,4 +237,19 @@
 			bias-pull-up;
 		};
 	};
+
+	ethernet_pins_default: ethernet {
+		pins_ethernet {
+			pinmux = <MT8516_PIN_0_EINT0__FUNC_EXT_TXD0>,
+				 <MT8516_PIN_1_EINT1__FUNC_EXT_TXD1>,
+				 <MT8516_PIN_5_EINT5__FUNC_EXT_RXER>,
+				 <MT8516_PIN_6_EINT6__FUNC_EXT_RXC>,
+				 <MT8516_PIN_7_EINT7__FUNC_EXT_RXDV>,
+				 <MT8516_PIN_8_EINT8__FUNC_EXT_RXD0>,
+				 <MT8516_PIN_9_EINT9__FUNC_EXT_RXD1>,
+				 <MT8516_PIN_12_EINT12__FUNC_EXT_TXEN>,
+				 <MT8516_PIN_38_MRG_DI__FUNC_EXT_MDIO>,
+				 <MT8516_PIN_39_MRG_DO__FUNC_EXT_MDC>;
+		};
+	};
 };
diff --git a/drivers/net/ethernet/mediatek/Kconfig b/drivers/net/ethernet/mediatek/Kconfig
index 4968352ba188..500c15e7ea4a 100644
--- a/drivers/net/ethernet/mediatek/Kconfig
+++ b/drivers/net/ethernet/mediatek/Kconfig
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0-only
 config NET_VENDOR_MEDIATEK
-	bool "MediaTek ethernet driver"
+	bool "MediaTek devices"
 	depends on ARCH_MEDIATEK || SOC_MT7621 || SOC_MT7620
 	---help---
 	  If you have a Mediatek SoC with ethernet, say Y.
@@ -14,4 +14,11 @@ config NET_MEDIATEK_SOC
 	  This driver supports the gigabit ethernet MACs in the
 	  MediaTek SoC family.
 
+config NET_MEDIATEK_STAR_EMAC
+	tristate "MediaTek STAR Ethernet MAC support"
+	select PHYLIB
+	help
+	  This driver supports the ethernet MAC IP first used on
+	  MediaTek MT85** SoCs.
+
 endif #NET_VENDOR_MEDIATEK
diff --git a/drivers/net/ethernet/mediatek/Makefile b/drivers/net/ethernet/mediatek/Makefile
index 2d8362f9341b..3a777b4a6cd3 100644
--- a/drivers/net/ethernet/mediatek/Makefile
+++ b/drivers/net/ethernet/mediatek/Makefile
@@ -3,5 +3,6 @@
 # Makefile for the Mediatek SoCs built-in ethernet macs
 #
 
-obj-$(CONFIG_NET_MEDIATEK_SOC)                 += mtk_eth.o
+obj-$(CONFIG_NET_MEDIATEK_SOC) += mtk_eth.o
 mtk_eth-y := mtk_eth_soc.o mtk_sgmii.o mtk_eth_path.o
+obj-$(CONFIG_NET_MEDIATEK_STAR_EMAC) += mtk_star_emac.o
diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c
new file mode 100644
index 000000000000..789c77af501f
--- /dev/null
+++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c
@@ -0,0 +1,1678 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2020 MediaTek Corporation
+ * Copyright (c) 2020 BayLibre SAS
+ *
+ * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/compiler.h>
+#include <linux/dma-mapping.h>
+#include <linux/etherdevice.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/mii.h>
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/of.h>
+#include <linux/of_mdio.h>
+#include <linux/of_net.h>
+#include <linux/platform_device.h>
+#include <linux/pm.h>
+#include <linux/regmap.h>
+#include <linux/skbuff.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+
+#define MTK_STAR_DRVNAME			"mtk_star_emac"
+
+#define MTK_STAR_WAIT_TIMEOUT			300
+#define MTK_STAR_MAX_FRAME_SIZE			1514
+#define MTK_STAR_SKB_ALIGNMENT			16
+#define MTK_STAR_NAPI_WEIGHT			64
+#define MTK_STAR_HASHTABLE_MC_LIMIT		256
+#define MTK_STAR_HASHTABLE_SIZE_MAX		512
+
+/* Normally we'd use NET_IP_ALIGN but on arm64 its value is 0 and it doesn't
+ * work for this controller.
+ */
+#define MTK_STAR_IP_ALIGN			2
+
+static const char *const mtk_star_clk_names[] = { "core", "reg", "trans" };
+#define MTK_STAR_NCLKS ARRAY_SIZE(mtk_star_clk_names)
+
+/* PHY Control Register 0 */
+#define MTK_STAR_REG_PHY_CTRL0			0x0000
+#define MTK_STAR_BIT_PHY_CTRL0_WTCMD		BIT(13)
+#define MTK_STAR_BIT_PHY_CTRL0_RDCMD		BIT(14)
+#define MTK_STAR_BIT_PHY_CTRL0_RWOK		BIT(15)
+#define MTK_STAR_MSK_PHY_CTRL0_PREG		GENMASK(12, 8)
+#define MTK_STAR_OFF_PHY_CTRL0_PREG		8
+#define MTK_STAR_MSK_PHY_CTRL0_RWDATA		GENMASK(31, 16)
+#define MTK_STAR_OFF_PHY_CTRL0_RWDATA		16
+
+/* PHY Control Register 1 */
+#define MTK_STAR_REG_PHY_CTRL1			0x0004
+#define MTK_STAR_BIT_PHY_CTRL1_LINK_ST		BIT(0)
+#define MTK_STAR_BIT_PHY_CTRL1_AN_EN		BIT(8)
+#define MTK_STAR_OFF_PHY_CTRL1_FORCE_SPD	9
+#define MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_10M	0x00
+#define MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_100M	0x01
+#define MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_1000M	0x02
+#define MTK_STAR_BIT_PHY_CTRL1_FORCE_DPX	BIT(11)
+#define MTK_STAR_BIT_PHY_CTRL1_FORCE_FC_RX	BIT(12)
+#define MTK_STAR_BIT_PHY_CTRL1_FORCE_FC_TX	BIT(13)
+
+/* MAC Configuration Register */
+#define MTK_STAR_REG_MAC_CFG			0x0008
+#define MTK_STAR_OFF_MAC_CFG_IPG		10
+#define MTK_STAR_VAL_MAC_CFG_IPG_96BIT		GENMASK(4, 0)
+#define MTK_STAR_BIT_MAC_CFG_MAXLEN_1522	BIT(16)
+#define MTK_STAR_BIT_MAC_CFG_AUTO_PAD		BIT(19)
+#define MTK_STAR_BIT_MAC_CFG_CRC_STRIP		BIT(20)
+#define MTK_STAR_BIT_MAC_CFG_VLAN_STRIP		BIT(22)
+#define MTK_STAR_BIT_MAC_CFG_NIC_PD		BIT(31)
+
+/* Flow-Control Configuration Register */
+#define MTK_STAR_REG_FC_CFG			0x000c
+#define MTK_STAR_BIT_FC_CFG_BP_EN		BIT(7)
+#define MTK_STAR_BIT_FC_CFG_UC_PAUSE_DIR	BIT(8)
+#define MTK_STAR_OFF_FC_CFG_SEND_PAUSE_TH	16
+#define MTK_STAR_MSK_FC_CFG_SEND_PAUSE_TH	GENMASK(27, 16)
+#define MTK_STAR_VAL_FC_CFG_SEND_PAUSE_TH_2K	0x800
+
+/* ARL Configuration Register */
+#define MTK_STAR_REG_ARL_CFG			0x0010
+#define MTK_STAR_BIT_ARL_CFG_HASH_ALG		BIT(0)
+#define MTK_STAR_BIT_ARL_CFG_MISC_MODE		BIT(4)
+
+/* MAC High and Low Bytes Registers */
+#define MTK_STAR_REG_MY_MAC_H			0x0014
+#define MTK_STAR_REG_MY_MAC_L			0x0018
+
+/* Hash Table Control Register */
+#define MTK_STAR_REG_HASH_CTRL			0x001c
+#define MTK_STAR_MSK_HASH_CTRL_HASH_BIT_ADDR	GENMASK(8, 0)
+#define MTK_STAR_BIT_HASH_CTRL_HASH_BIT_DATA	BIT(12)
+#define MTK_STAR_BIT_HASH_CTRL_ACC_CMD		BIT(13)
+#define MTK_STAR_BIT_HASH_CTRL_CMD_START	BIT(14)
+#define MTK_STAR_BIT_HASH_CTRL_BIST_OK		BIT(16)
+#define MTK_STAR_BIT_HASH_CTRL_BIST_DONE	BIT(17)
+#define MTK_STAR_BIT_HASH_CTRL_BIST_EN		BIT(31)
+
+/* TX DMA Control Register */
+#define MTK_STAR_REG_TX_DMA_CTRL		0x0034
+#define MTK_STAR_BIT_TX_DMA_CTRL_START		BIT(0)
+#define MTK_STAR_BIT_TX_DMA_CTRL_STOP		BIT(1)
+#define MTK_STAR_BIT_TX_DMA_CTRL_RESUME		BIT(2)
+
+/* RX DMA Control Register */
+#define MTK_STAR_REG_RX_DMA_CTRL		0x0038
+#define MTK_STAR_BIT_RX_DMA_CTRL_START		BIT(0)
+#define MTK_STAR_BIT_RX_DMA_CTRL_STOP		BIT(1)
+#define MTK_STAR_BIT_RX_DMA_CTRL_RESUME		BIT(2)
+
+/* DMA Address Registers */
+#define MTK_STAR_REG_TX_DPTR			0x003c
+#define MTK_STAR_REG_RX_DPTR			0x0040
+#define MTK_STAR_REG_TX_BASE_ADDR		0x0044
+#define MTK_STAR_REG_RX_BASE_ADDR		0x0048
+
+/* Interrupt Status Register */
+#define MTK_STAR_REG_INT_STS			0x0050
+#define MTK_STAR_REG_INT_STS_PORT_STS_CHG	BIT(2)
+#define MTK_STAR_REG_INT_STS_MIB_CNT_TH		BIT(3)
+#define MTK_STAR_BIT_INT_STS_FNRC		BIT(6)
+#define MTK_STAR_BIT_INT_STS_TNTC		BIT(8)
+
+/* Interrupt Mask Register */
+#define MTK_STAR_REG_INT_MASK			0x0054
+#define MTK_STAR_BIT_INT_MASK_FNRC		BIT(6)
+
+/* Misc. Config Register */
+#define MTK_STAR_REG_TEST1			0x005c
+#define MTK_STAR_BIT_TEST1_RST_HASH_MBIST	BIT(31)
+
+/* Extended Configuration Register */
+#define MTK_STAR_REG_EXT_CFG			0x0060
+#define MTK_STAR_OFF_EXT_CFG_SND_PAUSE_RLS	16
+#define MTK_STAR_MSK_EXT_CFG_SND_PAUSE_RLS	GENMASK(26, 16)
+#define MTK_STAR_VAL_EXT_CFG_SND_PAUSE_RLS_1K	0x400
+
+/* EthSys Configuration Register */
+#define MTK_STAR_REG_SYS_CONF			0x0094
+#define MTK_STAR_BIT_MII_PAD_OUT_ENABLE		BIT(0)
+#define MTK_STAR_BIT_EXT_MDC_MODE		BIT(1)
+#define MTK_STAR_BIT_SWC_MII_MODE		BIT(2)
+
+/* MAC Clock Configuration Register */
+#define MTK_STAR_REG_MAC_CLK_CONF		0x00ac
+#define MTK_STAR_MSK_MAC_CLK_CONF		GENMASK(7, 0)
+#define MTK_STAR_BIT_CLK_DIV_10			0x0a
+
+/* Counter registers. */
+#define MTK_STAR_REG_C_RXOKPKT			0x0100
+#define MTK_STAR_REG_C_RXOKBYTE			0x0104
+#define MTK_STAR_REG_C_RXRUNT			0x0108
+#define MTK_STAR_REG_C_RXLONG			0x010c
+#define MTK_STAR_REG_C_RXDROP			0x0110
+#define MTK_STAR_REG_C_RXCRC			0x0114
+#define MTK_STAR_REG_C_RXARLDROP		0x0118
+#define MTK_STAR_REG_C_RXVLANDROP		0x011c
+#define MTK_STAR_REG_C_RXCSERR			0x0120
+#define MTK_STAR_REG_C_RXPAUSE			0x0124
+#define MTK_STAR_REG_C_TXOKPKT			0x0128
+#define MTK_STAR_REG_C_TXOKBYTE			0x012c
+#define MTK_STAR_REG_C_TXPAUSECOL		0x0130
+#define MTK_STAR_REG_C_TXRTY			0x0134
+#define MTK_STAR_REG_C_TXSKIP			0x0138
+#define MTK_STAR_REG_C_TX_ARP			0x013c
+#define MTK_STAR_REG_C_RX_RERR			0x01d8
+#define MTK_STAR_REG_C_RX_UNI			0x01dc
+#define MTK_STAR_REG_C_RX_MULTI			0x01e0
+#define MTK_STAR_REG_C_RX_BROAD			0x01e4
+#define MTK_STAR_REG_C_RX_ALIGNERR		0x01e8
+#define MTK_STAR_REG_C_TX_UNI			0x01ec
+#define MTK_STAR_REG_C_TX_MULTI			0x01f0
+#define MTK_STAR_REG_C_TX_BROAD			0x01f4
+#define MTK_STAR_REG_C_TX_TIMEOUT		0x01f8
+#define MTK_STAR_REG_C_TX_LATECOL		0x01fc
+#define MTK_STAR_REG_C_RX_LENGTHERR		0x0214
+#define MTK_STAR_REG_C_RX_TWIST			0x0218
+
+/* Ethernet CFG Control */
+#define MTK_PERICFG_REG_NIC_CFG_CON		0x03c4
+#define MTK_PERICFG_MSK_NIC_CFG_CON_CFG_MII	GENMASK(3, 0)
+#define MTK_PERICFG_BIT_NIC_CFG_CON_RMII	BIT(0)
+
+/* Represents the actual structure of descriptors used by the MAC. We can
+ * reuse the same structure for both TX and RX - the layout is the same, only
+ * the flags differ slightly.
+ */
+struct mtk_star_ring_desc {
+	/* Contains both the status flags as well as packet length. */
+	u32 status;
+	u32 data_ptr;
+	u32 vtag;
+	u32 reserved;
+};
+
+#define MTK_STAR_DESC_MSK_LEN			GENMASK(15, 0)
+#define MTK_STAR_DESC_BIT_RX_CRCE		BIT(24)
+#define MTK_STAR_DESC_BIT_RX_OSIZE		BIT(25)
+#define MTK_STAR_DESC_BIT_INT			BIT(27)
+#define MTK_STAR_DESC_BIT_LS			BIT(28)
+#define MTK_STAR_DESC_BIT_FS			BIT(29)
+#define MTK_STAR_DESC_BIT_EOR			BIT(30)
+#define MTK_STAR_DESC_BIT_COWN			BIT(31)
+
+/* Helper structure for storing data read from/written to descriptors in order
+ * to limit reads from/writes to DMA memory.
+ */
+struct mtk_star_ring_desc_data {
+	unsigned int len;
+	unsigned int flags;
+	dma_addr_t dma_addr;
+	struct sk_buff *skb;
+};
+
+#define MTK_STAR_RING_NUM_DESCS			128
+#define MTK_STAR_NUM_TX_DESCS			MTK_STAR_RING_NUM_DESCS
+#define MTK_STAR_NUM_RX_DESCS			MTK_STAR_RING_NUM_DESCS
+#define MTK_STAR_NUM_DESCS_TOTAL		(MTK_STAR_RING_NUM_DESCS * 2)
+#define MTK_STAR_DMA_SIZE \
+		(MTK_STAR_NUM_DESCS_TOTAL * sizeof(struct mtk_star_ring_desc))
+
+struct mtk_star_ring {
+	struct mtk_star_ring_desc *descs;
+	struct sk_buff *skbs[MTK_STAR_RING_NUM_DESCS];
+	dma_addr_t dma_addrs[MTK_STAR_RING_NUM_DESCS];
+	unsigned int head;
+	unsigned int tail;
+};
+
+struct mtk_star_priv {
+	struct net_device *ndev;
+
+	struct regmap *regs;
+	struct regmap *pericfg;
+
+	struct clk_bulk_data clks[MTK_STAR_NCLKS];
+
+	void *ring_base;
+	struct mtk_star_ring_desc *descs_base;
+	dma_addr_t dma_addr;
+	struct mtk_star_ring tx_ring;
+	struct mtk_star_ring rx_ring;
+
+	struct mii_bus *mii;
+	struct napi_struct napi;
+
+	struct device_node *phy_node;
+	phy_interface_t phy_intf;
+	struct phy_device *phydev;
+	unsigned int link;
+	int speed;
+	int duplex;
+	int pause;
+
+	/* Protects against concurrent descriptor access. */
+	spinlock_t lock;
+
+	struct rtnl_link_stats64 stats;
+	struct work_struct stats_work;
+};
+
+static struct device *mtk_star_get_dev(struct mtk_star_priv *priv)
+{
+	return priv->ndev->dev.parent;
+}
+
+static const struct regmap_config mtk_star_regmap_config = {
+	.reg_bits		= 32,
+	.val_bits		= 32,
+	.reg_stride		= 4,
+	.disable_locking	= true,
+};
+
+static void mtk_star_ring_init(struct mtk_star_ring *ring,
+			       struct mtk_star_ring_desc *descs)
+{
+	memset(ring, 0, sizeof(*ring));
+	ring->descs = descs;
+	ring->head = 0;
+	ring->tail = 0;
+}
+
+static int mtk_star_ring_pop_tail(struct mtk_star_ring *ring,
+				  struct mtk_star_ring_desc_data *desc_data)
+{
+	struct mtk_star_ring_desc *desc = &ring->descs[ring->tail];
+	unsigned int status;
+
+	status = READ_ONCE(desc->status);
+	dma_rmb(); /* Make sure we read the status bits before checking it. */
+
+	if (!(status & MTK_STAR_DESC_BIT_COWN))
+		return -1;
+
+	desc_data->len = status & MTK_STAR_DESC_MSK_LEN;
+	desc_data->flags = status & ~MTK_STAR_DESC_MSK_LEN;
+	desc_data->dma_addr = ring->dma_addrs[ring->tail];
+	desc_data->skb = ring->skbs[ring->tail];
+
+	ring->dma_addrs[ring->tail] = 0;
+	ring->skbs[ring->tail] = NULL;
+
+	status &= MTK_STAR_DESC_BIT_COWN | MTK_STAR_DESC_BIT_EOR;
+
+	WRITE_ONCE(desc->data_ptr, 0);
+	WRITE_ONCE(desc->status, status);
+
+	ring->tail = (ring->tail + 1) % MTK_STAR_RING_NUM_DESCS;
+
+	return 0;
+}
+
+static void mtk_star_ring_push_head(struct mtk_star_ring *ring,
+				    struct mtk_star_ring_desc_data *desc_data,
+				    unsigned int flags)
+{
+	struct mtk_star_ring_desc *desc = &ring->descs[ring->head];
+	unsigned int status;
+
+	status = READ_ONCE(desc->status);
+
+	ring->skbs[ring->head] = desc_data->skb;
+	ring->dma_addrs[ring->head] = desc_data->dma_addr;
+
+	status |= desc_data->len;
+	if (flags)
+		status |= flags;
+
+	WRITE_ONCE(desc->data_ptr, desc_data->dma_addr);
+	WRITE_ONCE(desc->status, status);
+	status &= ~MTK_STAR_DESC_BIT_COWN;
+	/* Flush previous modifications before ownership change. */
+	dma_wmb();
+	WRITE_ONCE(desc->status, status);
+
+	ring->head = (ring->head + 1) % MTK_STAR_RING_NUM_DESCS;
+}
+
+static void
+mtk_star_ring_push_head_rx(struct mtk_star_ring *ring,
+			   struct mtk_star_ring_desc_data *desc_data)
+{
+	mtk_star_ring_push_head(ring, desc_data, 0);
+}
+
+static void
+mtk_star_ring_push_head_tx(struct mtk_star_ring *ring,
+			   struct mtk_star_ring_desc_data *desc_data)
+{
+	static const unsigned int flags = MTK_STAR_DESC_BIT_FS |
+					  MTK_STAR_DESC_BIT_LS |
+					  MTK_STAR_DESC_BIT_INT;
+
+	mtk_star_ring_push_head(ring, desc_data, flags);
+}
+
+static unsigned int mtk_star_ring_num_used_descs(struct mtk_star_ring *ring)
+{
+	return abs(ring->head - ring->tail);
+}
+
+static bool mtk_star_ring_full(struct mtk_star_ring *ring)
+{
+	return mtk_star_ring_num_used_descs(ring) == MTK_STAR_RING_NUM_DESCS;
+}
+
+static bool mtk_star_ring_descs_available(struct mtk_star_ring *ring)
+{
+	return mtk_star_ring_num_used_descs(ring) > 0;
+}
+
+static dma_addr_t mtk_star_dma_map_rx(struct mtk_star_priv *priv,
+				      struct sk_buff *skb)
+{
+	struct device *dev = mtk_star_get_dev(priv);
+
+	/* Data pointer for the RX DMA descriptor must be aligned to 4N + 2. */
+	return dma_map_single(dev, skb_tail_pointer(skb) - 2,
+			      skb_tailroom(skb), DMA_FROM_DEVICE);
+}
+
+static void mtk_star_dma_unmap_rx(struct mtk_star_priv *priv,
+				  struct mtk_star_ring_desc_data *desc_data)
+{
+	struct device *dev = mtk_star_get_dev(priv);
+
+	dma_unmap_single(dev, desc_data->dma_addr,
+			 skb_tailroom(desc_data->skb), DMA_FROM_DEVICE);
+}
+
+static dma_addr_t mtk_star_dma_map_tx(struct mtk_star_priv *priv,
+				      struct sk_buff *skb)
+{
+	struct device *dev = mtk_star_get_dev(priv);
+
+	return dma_map_single(dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE);
+}
+
+static void mtk_star_dma_unmap_tx(struct mtk_star_priv *priv,
+				  struct mtk_star_ring_desc_data *desc_data)
+{
+	struct device *dev = mtk_star_get_dev(priv);
+
+	return dma_unmap_single(dev, desc_data->dma_addr,
+				skb_headlen(desc_data->skb), DMA_TO_DEVICE);
+}
+
+static void mtk_star_nic_disable_pd(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_MAC_CFG,
+			   MTK_STAR_BIT_MAC_CFG_NIC_PD, 0);
+}
+
+/* Unmask the three interrupts we care about, mask all others. */
+static void mtk_star_intr_enable(struct mtk_star_priv *priv)
+{
+	unsigned int val = MTK_STAR_BIT_INT_STS_TNTC |
+			   MTK_STAR_BIT_INT_STS_FNRC |
+			   MTK_STAR_REG_INT_STS_MIB_CNT_TH;
+
+	regmap_write(priv->regs, MTK_STAR_REG_INT_MASK, ~val);
+}
+
+static void mtk_star_intr_disable(struct mtk_star_priv *priv)
+{
+	regmap_write(priv->regs, MTK_STAR_REG_INT_MASK, ~0);
+}
+
+static void mtk_star_intr_enable_tx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_BIT_INT_STS_TNTC, 0);
+}
+
+static void mtk_star_intr_enable_rx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_BIT_INT_STS_FNRC, 0);
+}
+
+static void mtk_star_intr_enable_stats(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_REG_INT_STS_MIB_CNT_TH, 0);
+}
+
+static void mtk_star_intr_disable_tx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_BIT_INT_STS_TNTC,
+			   MTK_STAR_BIT_INT_STS_TNTC);
+}
+
+static void mtk_star_intr_disable_rx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_BIT_INT_STS_FNRC,
+			   MTK_STAR_BIT_INT_STS_FNRC);
+}
+
+static void mtk_star_intr_disable_stats(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_INT_MASK,
+			   MTK_STAR_REG_INT_STS_MIB_CNT_TH,
+			   MTK_STAR_REG_INT_STS_MIB_CNT_TH);
+}
+
+static unsigned int mtk_star_intr_read(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	regmap_read(priv->regs, MTK_STAR_REG_INT_STS, &val);
+
+	return val;
+}
+
+static unsigned int mtk_star_intr_ack_all(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	val = mtk_star_intr_read(priv);
+	regmap_write(priv->regs, MTK_STAR_REG_INT_STS, val);
+
+	return val;
+}
+
+static void mtk_star_dma_init(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring_desc *desc;
+	unsigned int val;
+	int i;
+
+	priv->descs_base = (struct mtk_star_ring_desc *)priv->ring_base;
+
+	for (i = 0; i < MTK_STAR_NUM_DESCS_TOTAL; i++) {
+		desc = &priv->descs_base[i];
+
+		memset(desc, 0, sizeof(*desc));
+		desc->status = MTK_STAR_DESC_BIT_COWN;
+		if ((i == MTK_STAR_NUM_TX_DESCS - 1) ||
+		    (i == MTK_STAR_NUM_DESCS_TOTAL - 1))
+			desc->status |= MTK_STAR_DESC_BIT_EOR;
+	}
+
+	mtk_star_ring_init(&priv->tx_ring, priv->descs_base);
+	mtk_star_ring_init(&priv->rx_ring,
+			   priv->descs_base + MTK_STAR_NUM_TX_DESCS);
+
+	/* Set DMA pointers. */
+	val = (unsigned int)priv->dma_addr;
+	regmap_write(priv->regs, MTK_STAR_REG_TX_BASE_ADDR, val);
+	regmap_write(priv->regs, MTK_STAR_REG_TX_DPTR, val);
+
+	val += sizeof(struct mtk_star_ring_desc) * MTK_STAR_NUM_TX_DESCS;
+	regmap_write(priv->regs, MTK_STAR_REG_RX_BASE_ADDR, val);
+	regmap_write(priv->regs, MTK_STAR_REG_RX_DPTR, val);
+}
+
+static void mtk_star_dma_start(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_TX_DMA_CTRL,
+			   MTK_STAR_BIT_TX_DMA_CTRL_START,
+			   MTK_STAR_BIT_TX_DMA_CTRL_START);
+	regmap_update_bits(priv->regs, MTK_STAR_REG_RX_DMA_CTRL,
+			   MTK_STAR_BIT_RX_DMA_CTRL_START,
+			   MTK_STAR_BIT_RX_DMA_CTRL_START);
+}
+
+static void mtk_star_dma_stop(struct mtk_star_priv *priv)
+{
+	regmap_write(priv->regs, MTK_STAR_REG_TX_DMA_CTRL,
+		     MTK_STAR_BIT_TX_DMA_CTRL_STOP);
+	regmap_write(priv->regs, MTK_STAR_REG_RX_DMA_CTRL,
+		     MTK_STAR_BIT_RX_DMA_CTRL_STOP);
+}
+
+static void mtk_star_dma_disable(struct mtk_star_priv *priv)
+{
+	int i;
+
+	mtk_star_dma_stop(priv);
+
+	/* Take back all descriptors. */
+	for (i = 0; i < MTK_STAR_NUM_DESCS_TOTAL; i++)
+		priv->descs_base[i].status |= MTK_STAR_DESC_BIT_COWN;
+}
+
+static void mtk_star_dma_resume_rx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_RX_DMA_CTRL,
+			   MTK_STAR_BIT_RX_DMA_CTRL_RESUME,
+			   MTK_STAR_BIT_RX_DMA_CTRL_RESUME);
+}
+
+static void mtk_star_dma_resume_tx(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->regs, MTK_STAR_REG_TX_DMA_CTRL,
+			   MTK_STAR_BIT_TX_DMA_CTRL_RESUME,
+			   MTK_STAR_BIT_TX_DMA_CTRL_RESUME);
+}
+
+static void mtk_star_set_mac_addr(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	u8 *mac_addr = ndev->dev_addr;
+	unsigned int high, low;
+
+	high = mac_addr[0] << 8 | mac_addr[1] << 0;
+	low = mac_addr[2] << 24 | mac_addr[3] << 16 |
+	      mac_addr[4] << 8 | mac_addr[5];
+
+	regmap_write(priv->regs, MTK_STAR_REG_MY_MAC_H, high);
+	regmap_write(priv->regs, MTK_STAR_REG_MY_MAC_L, low);
+}
+
+static void mtk_star_reset_counters(struct mtk_star_priv *priv)
+{
+	static const unsigned int counter_regs[] = {
+		MTK_STAR_REG_C_RXOKPKT,
+		MTK_STAR_REG_C_RXOKBYTE,
+		MTK_STAR_REG_C_RXRUNT,
+		MTK_STAR_REG_C_RXLONG,
+		MTK_STAR_REG_C_RXDROP,
+		MTK_STAR_REG_C_RXCRC,
+		MTK_STAR_REG_C_RXARLDROP,
+		MTK_STAR_REG_C_RXVLANDROP,
+		MTK_STAR_REG_C_RXCSERR,
+		MTK_STAR_REG_C_RXPAUSE,
+		MTK_STAR_REG_C_TXOKPKT,
+		MTK_STAR_REG_C_TXOKBYTE,
+		MTK_STAR_REG_C_TXPAUSECOL,
+		MTK_STAR_REG_C_TXRTY,
+		MTK_STAR_REG_C_TXSKIP,
+		MTK_STAR_REG_C_TX_ARP,
+		MTK_STAR_REG_C_RX_RERR,
+		MTK_STAR_REG_C_RX_UNI,
+		MTK_STAR_REG_C_RX_MULTI,
+		MTK_STAR_REG_C_RX_BROAD,
+		MTK_STAR_REG_C_RX_ALIGNERR,
+		MTK_STAR_REG_C_TX_UNI,
+		MTK_STAR_REG_C_TX_MULTI,
+		MTK_STAR_REG_C_TX_BROAD,
+		MTK_STAR_REG_C_TX_TIMEOUT,
+		MTK_STAR_REG_C_TX_LATECOL,
+		MTK_STAR_REG_C_RX_LENGTHERR,
+		MTK_STAR_REG_C_RX_TWIST,
+	};
+
+	unsigned int i, val;
+
+	for (i = 0; i < ARRAY_SIZE(counter_regs); i++)
+		regmap_read(priv->regs, counter_regs[i], &val);
+}
+
+static void mtk_star_update_stat(struct mtk_star_priv *priv,
+				 unsigned int reg, u64 *stat)
+{
+	unsigned int val;
+
+	regmap_read(priv->regs, reg, &val);
+	*stat += val;
+}
+
+/* Try to get as many stats as possible from the internal registers instead
+ * of tracking them ourselves.
+ */
+static void mtk_star_update_stats(struct mtk_star_priv *priv)
+{
+	struct rtnl_link_stats64 *stats = &priv->stats;
+
+	/* OK packets and bytes. */
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXOKPKT, &stats->rx_packets);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_TXOKPKT, &stats->tx_packets);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXOKBYTE, &stats->rx_bytes);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_TXOKBYTE, &stats->tx_bytes);
+
+	/* RX & TX multicast. */
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RX_MULTI, &stats->multicast);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_TX_MULTI, &stats->multicast);
+
+	/* Collisions. */
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_TXPAUSECOL,
+			     &stats->collisions);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_TX_LATECOL,
+			     &stats->collisions);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXRUNT, &stats->collisions);
+
+	/* RX Errors. */
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RX_LENGTHERR,
+			     &stats->rx_length_errors);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXLONG,
+			     &stats->rx_over_errors);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXCRC, &stats->rx_crc_errors);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RX_ALIGNERR,
+			     &stats->rx_frame_errors);
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RXDROP,
+			     &stats->rx_fifo_errors);
+	/* Sum of the general RX error counter + all of the above. */
+	mtk_star_update_stat(priv, MTK_STAR_REG_C_RX_RERR, &stats->rx_errors);
+	stats->rx_errors += stats->rx_length_errors;
+	stats->rx_errors += stats->rx_over_errors;
+	stats->rx_errors += stats->rx_crc_errors;
+	stats->rx_errors += stats->rx_frame_errors;
+	stats->rx_errors += stats->rx_fifo_errors;
+}
+
+/* This runs in process context and parallel TX and RX paths executing in
+ * napi context may result in losing some stats data but this should happen
+ * seldom enough to be acceptable.
+ */
+static void mtk_star_update_stats_work(struct work_struct *work)
+{
+	struct mtk_star_priv *priv = container_of(work, struct mtk_star_priv,
+						 stats_work);
+
+	mtk_star_update_stats(priv);
+	mtk_star_reset_counters(priv);
+	mtk_star_intr_enable_stats(priv);
+}
+
+static struct sk_buff *mtk_star_alloc_skb(struct net_device *ndev)
+{
+	uintptr_t tail, offset;
+	struct sk_buff *skb;
+
+	skb = dev_alloc_skb(MTK_STAR_MAX_FRAME_SIZE);
+	if (!skb)
+		return NULL;
+
+	/* Align to 16 bytes. */
+	tail = (uintptr_t)skb_tail_pointer(skb);
+	if (tail & (MTK_STAR_SKB_ALIGNMENT - 1)) {
+		offset = tail & (MTK_STAR_SKB_ALIGNMENT - 1);
+		skb_reserve(skb, MTK_STAR_SKB_ALIGNMENT - offset);
+	}
+
+	/* Ensure 16-byte alignment of the skb pointer: eth_type_trans() will
+	 * extract the Ethernet header (14 bytes) so we need two more bytes.
+	 */
+	skb_reserve(skb, MTK_STAR_IP_ALIGN);
+
+	return skb;
+}
+
+static int mtk_star_prepare_rx_skbs(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	struct mtk_star_ring *ring = &priv->rx_ring;
+	struct device *dev = mtk_star_get_dev(priv);
+	struct mtk_star_ring_desc *desc;
+	struct sk_buff *skb;
+	dma_addr_t dma_addr;
+	int i;
+
+	for (i = 0; i < MTK_STAR_NUM_RX_DESCS; i++) {
+		skb = mtk_star_alloc_skb(ndev);
+		if (!skb)
+			return -ENOMEM;
+
+		dma_addr = mtk_star_dma_map_rx(priv, skb);
+		if (dma_mapping_error(dev, dma_addr)) {
+			dev_kfree_skb(skb);
+			return -ENOMEM;
+		}
+
+		desc = &ring->descs[i];
+		desc->data_ptr = dma_addr;
+		desc->status |= skb_tailroom(skb) & MTK_STAR_DESC_MSK_LEN;
+		desc->status &= ~MTK_STAR_DESC_BIT_COWN;
+		ring->skbs[i] = skb;
+		ring->dma_addrs[i] = dma_addr;
+	}
+
+	return 0;
+}
+
+static void
+mtk_star_ring_free_skbs(struct mtk_star_priv *priv, struct mtk_star_ring *ring,
+			void (*unmap_func)(struct mtk_star_priv *,
+					   struct mtk_star_ring_desc_data *))
+{
+	struct mtk_star_ring_desc_data desc_data;
+	struct mtk_star_ring_desc *desc;
+	int i;
+
+	for (i = 0; i < MTK_STAR_RING_NUM_DESCS; i++) {
+		if (!ring->dma_addrs[i])
+			continue;
+
+		desc = &ring->descs[i];
+
+		desc_data.dma_addr = ring->dma_addrs[i];
+		desc_data.skb = ring->skbs[i];
+
+		unmap_func(priv, &desc_data);
+		dev_kfree_skb(desc_data.skb);
+	}
+}
+
+static void mtk_star_free_rx_skbs(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring *ring = &priv->rx_ring;
+
+	mtk_star_ring_free_skbs(priv, ring, mtk_star_dma_unmap_rx);
+}
+
+static void mtk_star_free_tx_skbs(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring *ring = &priv->tx_ring;
+
+	mtk_star_ring_free_skbs(priv, ring, mtk_star_dma_unmap_tx);
+}
+
+/* All processing for TX and RX happens in the napi poll callback. */
+static irqreturn_t mtk_star_handle_irq(int irq, void *data)
+{
+	struct mtk_star_priv *priv;
+	struct net_device *ndev;
+	bool need_napi = false;
+	unsigned int status;
+
+	ndev = data;
+	priv = netdev_priv(ndev);
+
+	if (netif_running(ndev)) {
+		status = mtk_star_intr_read(priv);
+
+		if (status & MTK_STAR_BIT_INT_STS_TNTC) {
+			mtk_star_intr_disable_tx(priv);
+			need_napi = true;
+		}
+
+		if (status & MTK_STAR_BIT_INT_STS_FNRC) {
+			mtk_star_intr_disable_rx(priv);
+			need_napi = true;
+		}
+
+		if (need_napi)
+			napi_schedule(&priv->napi);
+
+		/* One of the counters reached 0x8000000 - update stats and
+		 * reset all counters.
+		 */
+		if (unlikely(status & MTK_STAR_REG_INT_STS_MIB_CNT_TH)) {
+			mtk_star_intr_disable_stats(priv);
+			schedule_work(&priv->stats_work);
+		}
+
+		mtk_star_intr_ack_all(priv);
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* Wait for the completion of any previous command - CMD_START bit must be
+ * cleared by hardware.
+ */
+static int mtk_star_hash_wait_cmd_start(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	return regmap_read_poll_timeout_atomic(priv->regs,
+				MTK_STAR_REG_HASH_CTRL, val,
+				!(val & MTK_STAR_BIT_HASH_CTRL_CMD_START),
+				10, MTK_STAR_WAIT_TIMEOUT);
+}
+
+static int mtk_star_hash_wait_ok(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+	int ret;
+
+	/* Wait for BIST_DONE bit. */
+	ret = regmap_read_poll_timeout_atomic(priv->regs,
+					MTK_STAR_REG_HASH_CTRL, val,
+					val & MTK_STAR_BIT_HASH_CTRL_BIST_DONE,
+					10, MTK_STAR_WAIT_TIMEOUT);
+	if (ret)
+		return ret;
+
+	/* Check the BIST_OK bit. */
+	regmap_read(priv->regs, MTK_STAR_REG_HASH_CTRL, &val);
+	if (!(val & MTK_STAR_BIT_HASH_CTRL_BIST_OK))
+		return -EIO;
+
+	return 0;
+}
+
+static int mtk_star_set_hashbit(struct mtk_star_priv *priv,
+				unsigned int hash_addr)
+{
+	unsigned int val;
+	int ret;
+
+	ret = mtk_star_hash_wait_cmd_start(priv);
+	if (ret)
+		return ret;
+
+	val = hash_addr & MTK_STAR_MSK_HASH_CTRL_HASH_BIT_ADDR;
+	val |= MTK_STAR_BIT_HASH_CTRL_ACC_CMD;
+	val |= MTK_STAR_BIT_HASH_CTRL_CMD_START;
+	val |= MTK_STAR_BIT_HASH_CTRL_BIST_EN;
+	val |= MTK_STAR_BIT_HASH_CTRL_HASH_BIT_DATA;
+	regmap_write(priv->regs, MTK_STAR_REG_HASH_CTRL, val);
+
+	return mtk_star_hash_wait_ok(priv);
+}
+
+static int mtk_star_reset_hash_table(struct mtk_star_priv *priv)
+{
+	int ret;
+
+	ret = mtk_star_hash_wait_cmd_start(priv);
+	if (ret)
+		return ret;
+
+	regmap_update_bits(priv->regs, MTK_STAR_REG_HASH_CTRL,
+			   MTK_STAR_BIT_HASH_CTRL_BIST_EN,
+			   MTK_STAR_BIT_HASH_CTRL_BIST_EN);
+	regmap_update_bits(priv->regs, MTK_STAR_REG_TEST1,
+			   MTK_STAR_BIT_TEST1_RST_HASH_MBIST,
+			   MTK_STAR_BIT_TEST1_RST_HASH_MBIST);
+
+	return mtk_star_hash_wait_ok(priv);
+}
+
+static void mtk_star_phy_config(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	if (priv->speed == SPEED_1000)
+		val = MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_1000M;
+	else if (priv->speed == SPEED_100)
+		val = MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_100M;
+	else
+		val = MTK_STAR_VAL_PHY_CTRL1_FORCE_SPD_10M;
+	val <<= MTK_STAR_OFF_PHY_CTRL1_FORCE_SPD;
+
+	val |= MTK_STAR_BIT_PHY_CTRL1_AN_EN;
+	val |= MTK_STAR_BIT_PHY_CTRL1_FORCE_FC_RX;
+	val |= MTK_STAR_BIT_PHY_CTRL1_FORCE_FC_TX;
+	/* Only full-duplex supported for now. */
+	val |= MTK_STAR_BIT_PHY_CTRL1_FORCE_DPX;
+
+	regmap_write(priv->regs, MTK_STAR_REG_PHY_CTRL1, val);
+
+	if (priv->pause) {
+		val = MTK_STAR_VAL_FC_CFG_SEND_PAUSE_TH_2K;
+		val <<= MTK_STAR_OFF_FC_CFG_SEND_PAUSE_TH;
+		val |= MTK_STAR_BIT_FC_CFG_UC_PAUSE_DIR;
+	} else {
+		val = 0;
+	}
+
+	regmap_update_bits(priv->regs, MTK_STAR_REG_FC_CFG,
+			   MTK_STAR_MSK_FC_CFG_SEND_PAUSE_TH |
+			   MTK_STAR_BIT_FC_CFG_UC_PAUSE_DIR, val);
+
+	if (priv->pause) {
+		val = MTK_STAR_VAL_EXT_CFG_SND_PAUSE_RLS_1K;
+		val <<= MTK_STAR_OFF_EXT_CFG_SND_PAUSE_RLS;
+	} else {
+		val = 0;
+	}
+
+	regmap_update_bits(priv->regs, MTK_STAR_REG_EXT_CFG,
+			   MTK_STAR_MSK_EXT_CFG_SND_PAUSE_RLS, val);
+}
+
+static void mtk_star_adjust_link(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	struct phy_device *phydev = priv->phydev;
+	bool new_state = false;
+
+	if (phydev->link) {
+		if (!priv->link) {
+			priv->link = phydev->link;
+			new_state = true;
+		}
+
+		if (priv->speed != phydev->speed) {
+			priv->speed = phydev->speed;
+			new_state = true;
+		}
+
+		if (priv->pause != phydev->pause) {
+			priv->pause = phydev->pause;
+			new_state = true;
+		}
+	} else {
+		if (priv->link) {
+			priv->link = phydev->link;
+			new_state = true;
+		}
+	}
+
+	if (new_state) {
+		if (phydev->link)
+			mtk_star_phy_config(priv);
+
+		phy_print_status(ndev->phydev);
+	}
+}
+
+static void mtk_star_init_config(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	val = (MTK_STAR_BIT_MII_PAD_OUT_ENABLE |
+	       MTK_STAR_BIT_EXT_MDC_MODE |
+	       MTK_STAR_BIT_SWC_MII_MODE);
+
+	regmap_write(priv->regs, MTK_STAR_REG_SYS_CONF, val);
+	regmap_update_bits(priv->regs, MTK_STAR_REG_MAC_CLK_CONF,
+			   MTK_STAR_MSK_MAC_CLK_CONF,
+			   MTK_STAR_BIT_CLK_DIV_10);
+}
+
+static void mtk_star_set_mode_rmii(struct mtk_star_priv *priv)
+{
+	regmap_update_bits(priv->pericfg, MTK_PERICFG_REG_NIC_CFG_CON,
+			   MTK_PERICFG_MSK_NIC_CFG_CON_CFG_MII,
+			   MTK_PERICFG_BIT_NIC_CFG_CON_RMII);
+}
+
+static int mtk_star_enable(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	unsigned int val;
+	int ret;
+
+	mtk_star_nic_disable_pd(priv);
+	mtk_star_intr_disable(priv);
+	mtk_star_dma_stop(priv);
+
+	mtk_star_set_mac_addr(ndev);
+
+	/* Configure the MAC */
+	val = MTK_STAR_VAL_MAC_CFG_IPG_96BIT;
+	val <<= MTK_STAR_OFF_MAC_CFG_IPG;
+	val |= MTK_STAR_BIT_MAC_CFG_MAXLEN_1522;
+	val |= MTK_STAR_BIT_MAC_CFG_AUTO_PAD;
+	val |= MTK_STAR_BIT_MAC_CFG_CRC_STRIP;
+	regmap_write(priv->regs, MTK_STAR_REG_MAC_CFG, val);
+
+	/* Enable Hash Table BIST and reset it */
+	ret = mtk_star_reset_hash_table(priv);
+	if (ret)
+		return ret;
+
+	/* Setup the hashing algorithm */
+	regmap_update_bits(priv->regs, MTK_STAR_REG_ARL_CFG,
+			   MTK_STAR_BIT_ARL_CFG_HASH_ALG |
+			   MTK_STAR_BIT_ARL_CFG_MISC_MODE, 0);
+
+	/* Don't strip VLAN tags */
+	regmap_update_bits(priv->regs, MTK_STAR_REG_MAC_CFG,
+			   MTK_STAR_BIT_MAC_CFG_VLAN_STRIP, 0);
+
+	/* Setup DMA */
+	mtk_star_dma_init(priv);
+
+	ret = mtk_star_prepare_rx_skbs(ndev);
+	if (ret)
+		goto err_out;
+
+	/* Request the interrupt */
+	ret = request_irq(ndev->irq, mtk_star_handle_irq,
+			  IRQF_TRIGGER_FALLING, ndev->name, ndev);
+	if (ret)
+		goto err_free_skbs;
+
+	napi_enable(&priv->napi);
+
+	mtk_star_intr_ack_all(priv);
+	mtk_star_intr_enable(priv);
+
+	/* Connect to and start PHY */
+	priv->phydev = of_phy_connect(ndev, priv->phy_node,
+				      mtk_star_adjust_link, 0, priv->phy_intf);
+	if (!priv->phydev) {
+		netdev_err(ndev, "failed to connect to PHY\n");
+		goto err_free_irq;
+	}
+
+	mtk_star_dma_start(priv);
+	phy_start(priv->phydev);
+	netif_start_queue(ndev);
+
+	return 0;
+
+err_free_irq:
+	free_irq(ndev->irq, ndev);
+err_free_skbs:
+	mtk_star_free_rx_skbs(priv);
+err_out:
+	return ret;
+}
+
+static void mtk_star_disable(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+
+	netif_stop_queue(ndev);
+	napi_disable(&priv->napi);
+	mtk_star_intr_disable(priv);
+	mtk_star_dma_disable(priv);
+	mtk_star_intr_ack_all(priv);
+	phy_stop(priv->phydev);
+	phy_disconnect(priv->phydev);
+	free_irq(ndev->irq, ndev);
+	mtk_star_free_rx_skbs(priv);
+	mtk_star_free_tx_skbs(priv);
+}
+
+static int mtk_star_netdev_open(struct net_device *ndev)
+{
+	return mtk_star_enable(ndev);
+}
+
+static int mtk_star_netdev_stop(struct net_device *ndev)
+{
+	mtk_star_disable(ndev);
+
+	return 0;
+}
+
+static int mtk_star_netdev_ioctl(struct net_device *ndev,
+				 struct ifreq *req, int cmd)
+{
+	if (!netif_running(ndev))
+		return -EINVAL;
+
+	return phy_mii_ioctl(ndev->phydev, req, cmd);
+}
+
+static int mtk_star_netdev_start_xmit(struct sk_buff *skb,
+				      struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	struct mtk_star_ring *ring = &priv->tx_ring;
+	struct device *dev = mtk_star_get_dev(priv);
+	struct mtk_star_ring_desc_data desc_data;
+
+	desc_data.dma_addr = mtk_star_dma_map_tx(priv, skb);
+	if (dma_mapping_error(dev, desc_data.dma_addr))
+		goto err_drop_packet;
+
+	desc_data.skb = skb;
+	desc_data.len = skb->len;
+
+	spin_lock_bh(&priv->lock);
+
+	mtk_star_ring_push_head_tx(ring, &desc_data);
+
+	netdev_sent_queue(ndev, skb->len);
+
+	if (mtk_star_ring_full(ring))
+		netif_stop_queue(ndev);
+
+	spin_unlock_bh(&priv->lock);
+
+	mtk_star_dma_resume_tx(priv);
+
+	return NETDEV_TX_OK;
+
+err_drop_packet:
+	dev_kfree_skb(skb);
+	ndev->stats.tx_dropped++;
+	return NETDEV_TX_BUSY;
+}
+
+/* Returns the number of bytes sent or a negative number on the first
+ * descriptor owned by DMA.
+ */
+static int mtk_star_tx_complete_one(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring *ring = &priv->tx_ring;
+	struct mtk_star_ring_desc_data desc_data;
+	int ret;
+
+	ret = mtk_star_ring_pop_tail(ring, &desc_data);
+	if (ret)
+		return ret;
+
+	mtk_star_dma_unmap_tx(priv, &desc_data);
+	ret = desc_data.skb->len;
+	dev_kfree_skb_irq(desc_data.skb);
+
+	return ret;
+}
+
+static void mtk_star_tx_complete_all(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring *ring = &priv->tx_ring;
+	struct net_device *ndev = priv->ndev;
+	int ret, pkts_compl, bytes_compl;
+	bool wake = false;
+
+	spin_lock(&priv->lock);
+
+	for (pkts_compl = 0, bytes_compl = 0;;
+	     pkts_compl++, bytes_compl += ret, wake = true) {
+		if (!mtk_star_ring_descs_available(ring))
+			break;
+
+		ret = mtk_star_tx_complete_one(priv);
+		if (ret < 0)
+			break;
+	}
+
+	netdev_completed_queue(ndev, pkts_compl, bytes_compl);
+
+	if (wake && netif_queue_stopped(ndev))
+		netif_wake_queue(ndev);
+
+	mtk_star_intr_enable_tx(priv);
+
+	spin_unlock(&priv->lock);
+}
+
+static void mtk_star_netdev_get_stats64(struct net_device *ndev,
+					struct rtnl_link_stats64 *stats)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+
+	mtk_star_update_stats(priv);
+
+	memcpy(stats, &priv->stats, sizeof(*stats));
+}
+
+static void mtk_star_set_rx_mode(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	struct netdev_hw_addr *hw_addr;
+	unsigned int hash_addr, i;
+	int ret;
+
+	if (ndev->flags & IFF_PROMISC) {
+		regmap_update_bits(priv->regs, MTK_STAR_REG_ARL_CFG,
+				   MTK_STAR_BIT_ARL_CFG_MISC_MODE,
+				   MTK_STAR_BIT_ARL_CFG_MISC_MODE);
+	} else if (netdev_mc_count(ndev) > MTK_STAR_HASHTABLE_MC_LIMIT ||
+		   ndev->flags & IFF_ALLMULTI) {
+		for (i = 0; i < MTK_STAR_HASHTABLE_SIZE_MAX; i++) {
+			ret = mtk_star_set_hashbit(priv, i);
+			if (ret)
+				goto hash_fail;
+		}
+	} else {
+		/* Clear previous settings. */
+		ret = mtk_star_reset_hash_table(priv);
+		if (ret)
+			goto hash_fail;
+
+		netdev_for_each_mc_addr(hw_addr, ndev) {
+			hash_addr = (hw_addr->addr[0] & 0x01) << 8;
+			hash_addr += hw_addr->addr[5];
+			ret = mtk_star_set_hashbit(priv, hash_addr);
+			if (ret)
+				goto hash_fail;
+		}
+	}
+
+	return;
+
+hash_fail:
+	if (ret == -ETIMEDOUT)
+		netdev_err(ndev, "setting hash bit timed out\n");
+	else
+		/* Should be -EIO */
+		netdev_err(ndev, "unable to set hash bit");
+}
+
+static const struct net_device_ops mtk_star_netdev_ops = {
+	.ndo_open		= mtk_star_netdev_open,
+	.ndo_stop		= mtk_star_netdev_stop,
+	.ndo_start_xmit		= mtk_star_netdev_start_xmit,
+	.ndo_get_stats64	= mtk_star_netdev_get_stats64,
+	.ndo_set_rx_mode	= mtk_star_set_rx_mode,
+	.ndo_do_ioctl		= mtk_star_netdev_ioctl,
+	.ndo_set_mac_address	= eth_mac_addr,
+	.ndo_validate_addr	= eth_validate_addr,
+};
+
+static void mtk_star_get_drvinfo(struct net_device *dev,
+				 struct ethtool_drvinfo *info)
+{
+	strlcpy(info->driver, MTK_STAR_DRVNAME, sizeof(info->driver));
+}
+
+/* TODO Add ethtool stats. */
+static const struct ethtool_ops mtk_star_ethtool_ops = {
+	.get_drvinfo		= mtk_star_get_drvinfo,
+	.get_link		= ethtool_op_get_link,
+	.get_link_ksettings	= phy_ethtool_get_link_ksettings,
+	.set_link_ksettings	= phy_ethtool_set_link_ksettings,
+};
+
+static int mtk_star_receive_packet(struct mtk_star_priv *priv)
+{
+	struct mtk_star_ring *ring = &priv->rx_ring;
+	struct device *dev = mtk_star_get_dev(priv);
+	struct mtk_star_ring_desc_data desc_data;
+	struct net_device *ndev = priv->ndev;
+	struct sk_buff *curr_skb, *new_skb;
+	dma_addr_t new_dma_addr;
+	int ret;
+
+	spin_lock(&priv->lock);
+	ret = mtk_star_ring_pop_tail(ring, &desc_data);
+	spin_unlock(&priv->lock);
+	if (ret)
+		return -1;
+
+	curr_skb = desc_data.skb;
+
+	if ((desc_data.flags & MTK_STAR_DESC_BIT_RX_CRCE) ||
+	    (desc_data.flags & MTK_STAR_DESC_BIT_RX_OSIZE)) {
+		/* Error packet -> drop and reuse skb. */
+		new_skb = curr_skb;
+		goto push_new_skb;
+	}
+
+	/* Prepare new skb before receiving the current one. Reuse the current
+	 * skb if we fail at any point.
+	 */
+	new_skb = mtk_star_alloc_skb(ndev);
+	if (!new_skb) {
+		ndev->stats.rx_dropped++;
+		new_skb = curr_skb;
+		goto push_new_skb;
+	}
+
+	new_dma_addr = mtk_star_dma_map_rx(priv, new_skb);
+	if (dma_mapping_error(dev, new_dma_addr)) {
+		ndev->stats.rx_dropped++;
+		dev_kfree_skb(new_skb);
+		new_skb = curr_skb;
+		netdev_err(ndev, "DMA mapping error of RX descriptor\n");
+		goto push_new_skb;
+	}
+
+	/* We can't fail anymore at this point: it's safe to unmap the skb. */
+	mtk_star_dma_unmap_rx(priv, &desc_data);
+
+	skb_put(desc_data.skb, desc_data.len);
+	desc_data.skb->ip_summed = CHECKSUM_NONE;
+	desc_data.skb->protocol = eth_type_trans(desc_data.skb, ndev);
+	desc_data.skb->dev = ndev;
+	netif_receive_skb(desc_data.skb);
+
+push_new_skb:
+	desc_data.dma_addr = new_dma_addr;
+	desc_data.len = skb_tailroom(new_skb);
+	desc_data.skb = new_skb;
+
+	spin_lock(&priv->lock);
+	mtk_star_ring_push_head_rx(ring, &desc_data);
+	spin_unlock(&priv->lock);
+
+	return 0;
+}
+
+static int mtk_star_process_rx(struct mtk_star_priv *priv, int budget)
+{
+	int received, ret;
+
+	for (received = 0, ret = 0; received < budget && ret == 0; received++)
+		ret = mtk_star_receive_packet(priv);
+
+	mtk_star_dma_resume_rx(priv);
+
+	return received;
+}
+
+static int mtk_star_poll(struct napi_struct *napi, int budget)
+{
+	struct mtk_star_priv *priv;
+	int received = 0;
+
+	priv = container_of(napi, struct mtk_star_priv, napi);
+
+	/* Clean-up all TX descriptors. */
+	mtk_star_tx_complete_all(priv);
+	/* Receive up to $budget packets. */
+	received = mtk_star_process_rx(priv, budget);
+
+	if (received < budget) {
+		napi_complete_done(napi, received);
+		mtk_star_intr_enable_rx(priv);
+	}
+
+	return received;
+}
+
+static void mtk_star_mdio_rwok_clear(struct mtk_star_priv *priv)
+{
+	regmap_write(priv->regs, MTK_STAR_REG_PHY_CTRL0,
+		     MTK_STAR_BIT_PHY_CTRL0_RWOK);
+}
+
+static int mtk_star_mdio_rwok_wait(struct mtk_star_priv *priv)
+{
+	unsigned int val;
+
+	return regmap_read_poll_timeout(priv->regs, MTK_STAR_REG_PHY_CTRL0,
+					val, val & MTK_STAR_BIT_PHY_CTRL0_RWOK,
+					10, MTK_STAR_WAIT_TIMEOUT);
+}
+
+static int mtk_star_mdio_read(struct mii_bus *mii, int phy_id, int regnum)
+{
+	struct mtk_star_priv *priv = mii->priv;
+	unsigned int val, data;
+	int ret;
+
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
+	mtk_star_mdio_rwok_clear(priv);
+
+	val = (regnum << MTK_STAR_OFF_PHY_CTRL0_PREG);
+	val &= MTK_STAR_MSK_PHY_CTRL0_PREG;
+	val |= MTK_STAR_BIT_PHY_CTRL0_RDCMD;
+
+	regmap_write(priv->regs, MTK_STAR_REG_PHY_CTRL0, val);
+
+	ret = mtk_star_mdio_rwok_wait(priv);
+	if (ret)
+		return ret;
+
+	regmap_read(priv->regs, MTK_STAR_REG_PHY_CTRL0, &data);
+
+	data &= MTK_STAR_MSK_PHY_CTRL0_RWDATA;
+	data >>= MTK_STAR_OFF_PHY_CTRL0_RWDATA;
+
+	return data;
+}
+
+static int mtk_star_mdio_write(struct mii_bus *mii, int phy_id,
+			       int regnum, u16 data)
+{
+	struct mtk_star_priv *priv = mii->priv;
+	unsigned int val;
+
+	if (regnum & MII_ADDR_C45)
+		return -EOPNOTSUPP;
+
+	mtk_star_mdio_rwok_clear(priv);
+
+	val = data;
+	val <<= MTK_STAR_OFF_PHY_CTRL0_RWDATA;
+	val &= MTK_STAR_MSK_PHY_CTRL0_RWDATA;
+	regnum <<= MTK_STAR_OFF_PHY_CTRL0_PREG;
+	regnum &= MTK_STAR_MSK_PHY_CTRL0_PREG;
+	val |= regnum;
+	val |= MTK_STAR_BIT_PHY_CTRL0_WTCMD;
+
+	regmap_write(priv->regs, MTK_STAR_REG_PHY_CTRL0, val);
+
+	return mtk_star_mdio_rwok_wait(priv);
+}
+
+static int mtk_star_mdio_init(struct net_device *ndev)
+{
+	struct mtk_star_priv *priv = netdev_priv(ndev);
+	struct device *dev = mtk_star_get_dev(priv);
+	struct device_node *of_node, *mdio_node;
+	int ret;
+
+	of_node = dev->of_node;
+
+	mdio_node = of_get_child_by_name(of_node, "mdio");
+	if (!mdio_node)
+		return -ENODEV;
+
+	if (!of_device_is_available(mdio_node)) {
+		ret = -ENODEV;
+		goto out_put_node;
+	}
+
+	priv->mii = devm_mdiobus_alloc(dev);
+	if (!priv->mii) {
+		ret = -ENOMEM;
+		goto out_put_node;
+	}
+
+	snprintf(priv->mii->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
+	priv->mii->name = "mtk-mac-mdio";
+	priv->mii->parent = dev;
+	priv->mii->read = mtk_star_mdio_read;
+	priv->mii->write = mtk_star_mdio_write;
+	priv->mii->priv = priv;
+
+	ret = of_mdiobus_register(priv->mii, mdio_node);
+
+out_put_node:
+	of_node_put(mdio_node);
+	return ret;
+}
+
+static int mtk_star_suspend(struct device *dev)
+{
+	struct mtk_star_priv *priv;
+	struct net_device *ndev;
+
+	ndev = dev_get_drvdata(dev);
+	priv = netdev_priv(ndev);
+
+	if (netif_running(ndev))
+		mtk_star_disable(ndev);
+
+	clk_bulk_disable_unprepare(MTK_STAR_NCLKS, priv->clks);
+
+	return 0;
+}
+
+static int mtk_star_resume(struct device *dev)
+{
+	struct mtk_star_priv *priv;
+	struct net_device *ndev;
+	int ret;
+
+	ndev = dev_get_drvdata(dev);
+	priv = netdev_priv(ndev);
+
+	ret = clk_bulk_prepare_enable(MTK_STAR_NCLKS, priv->clks);
+	if (ret)
+		return ret;
+
+	if (netif_running(ndev)) {
+		ret = mtk_star_enable(ndev);
+		if (ret)
+			clk_bulk_disable_unprepare(MTK_STAR_NCLKS, priv->clks);
+	}
+
+	return ret;
+}
+
+static void mtk_star_clk_disable_unprepare(void *data)
+{
+	struct mtk_star_priv *priv = data;
+
+	clk_bulk_disable_unprepare(MTK_STAR_NCLKS, priv->clks);
+}
+
+static void mtk_star_mdiobus_unregister(void *data)
+{
+	struct mtk_star_priv *priv = data;
+
+	mdiobus_unregister(priv->mii);
+}
+
+static void mtk_star_unregister_netdev(void *data)
+{
+	struct net_device *ndev = data;
+
+	unregister_netdev(ndev);
+}
+
+static int mtk_star_probe(struct platform_device *pdev)
+{
+	struct device_node *of_node;
+	struct mtk_star_priv *priv;
+	struct net_device *ndev;
+	struct device *dev;
+	void __iomem *base;
+	int ret, i;
+
+	dev = &pdev->dev;
+	of_node = dev->of_node;
+
+	ndev = devm_alloc_etherdev(dev, sizeof(*priv));
+	if (!ndev)
+		return -ENOMEM;
+
+	priv = netdev_priv(ndev);
+	priv->ndev = ndev;
+	SET_NETDEV_DEV(ndev, dev);
+	platform_set_drvdata(pdev, ndev);
+
+	ndev->min_mtu = ETH_ZLEN;
+	ndev->max_mtu = MTK_STAR_MAX_FRAME_SIZE;
+
+	spin_lock_init(&priv->lock);
+	INIT_WORK(&priv->stats_work, mtk_star_update_stats_work);
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	/* We won't be checking the return values of regmap read & write
+	 * functions. They can only fail for mmio if there's a clock attached
+	 * to regmap which is not the case here.
+	 */
+	priv->regs = devm_regmap_init_mmio(dev, base,
+					   &mtk_star_regmap_config);
+	if (IS_ERR(priv->regs))
+		return PTR_ERR(priv->regs);
+
+	priv->pericfg = syscon_regmap_lookup_by_phandle(of_node,
+							"mediatek,pericfg");
+	if (IS_ERR(priv->pericfg)) {
+		dev_err(dev, "Failed to lookup the PERICFG syscon\n");
+		return PTR_ERR(priv->pericfg);
+	}
+
+	ndev->irq = platform_get_irq(pdev, 0);
+	if (ndev->irq < 0)
+		return ndev->irq;
+
+	for (i = 0; i < MTK_STAR_NCLKS; i++)
+		priv->clks[i].id = mtk_star_clk_names[i];
+	ret = devm_clk_bulk_get(dev, MTK_STAR_NCLKS, priv->clks);
+	if (ret)
+		return ret;
+
+	ret = clk_bulk_prepare_enable(MTK_STAR_NCLKS, priv->clks);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev,
+				       mtk_star_clk_disable_unprepare, priv);
+	if (ret)
+		return ret;
+
+	ret = of_get_phy_mode(of_node, &priv->phy_intf);
+	if (ret) {
+		return ret;
+	} else if (priv->phy_intf != PHY_INTERFACE_MODE_RMII) {
+		dev_err(dev, "unsupported phy mode: %s\n",
+			phy_modes(priv->phy_intf));
+		return -EINVAL;
+	}
+
+	priv->phy_node = of_parse_phandle(of_node, "phy-handle", 0);
+	if (!priv->phy_node) {
+		dev_err(dev, "failed to retrieve the phy handle from device tree\n");
+		return -ENODEV;
+	}
+
+	mtk_star_set_mode_rmii(priv);
+
+	ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
+	if (ret) {
+		dev_err(dev, "unsupported DMA mask\n");
+		return ret;
+	}
+
+	priv->ring_base = dmam_alloc_coherent(dev, MTK_STAR_DMA_SIZE,
+					      &priv->dma_addr,
+					      GFP_KERNEL | GFP_DMA);
+	if (!priv->ring_base)
+		return -ENOMEM;
+
+	mtk_star_nic_disable_pd(priv);
+	mtk_star_init_config(priv);
+
+	ret = mtk_star_mdio_init(ndev);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, mtk_star_mdiobus_unregister, priv);
+	if (ret)
+		return ret;
+
+	ret = eth_platform_get_mac_address(dev, ndev->dev_addr);
+	if (ret || !is_valid_ether_addr(ndev->dev_addr))
+		eth_hw_addr_random(ndev);
+
+	ndev->netdev_ops = &mtk_star_netdev_ops;
+	ndev->ethtool_ops = &mtk_star_ethtool_ops;
+
+	netif_napi_add(ndev, &priv->napi, mtk_star_poll, MTK_STAR_NAPI_WEIGHT);
+
+	ret = register_netdev(ndev);
+	if (ret)
+		return ret;
+
+	ret = devm_add_action_or_reset(dev, mtk_star_unregister_netdev, ndev);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id mtk_star_of_match[] = {
+	{ .compatible = "mediatek,mt8516-eth", },
+	{ .compatible = "mediatek,mt8518-eth", },
+	{ .compatible = "mediatek,mt8175-eth", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mtk_star_of_match);
+
+static SIMPLE_DEV_PM_OPS(mtk_star_pm_ops,
+			 mtk_star_suspend, mtk_star_resume);
+
+static struct platform_driver mtk_star_driver = {
+	.driver = {
+		.name = MTK_STAR_DRVNAME,
+		.pm = &mtk_star_pm_ops,
+		.of_match_table = of_match_ptr(mtk_star_of_match),
+	},
+	.probe = mtk_star_probe,
+};
+module_platform_driver(mtk_star_driver);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>");
+MODULE_DESCRIPTION("Mediatek STAR Ethernet MAC Driver");
+MODULE_LICENSE("GPL");