1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Copyright (C) 2019 IBM Corp. */
3
4#include <linux/bitfield.h>
5#include <linux/delay.h>
6#include <linux/iopoll.h>
7#include <linux/mdio.h>
8#include <linux/module.h>
9#include <linux/of.h>
10#include <linux/of_mdio.h>
11#include <linux/phy.h>
12#include <linux/platform_device.h>
13
14#define DRV_NAME "mdio-aspeed"
15
16#define ASPEED_MDIO_CTRL		0x0
17#define   ASPEED_MDIO_CTRL_FIRE		BIT(31)
18#define   ASPEED_MDIO_CTRL_ST		BIT(28)
19#define     ASPEED_MDIO_CTRL_ST_C45	0
20#define     ASPEED_MDIO_CTRL_ST_C22	1
21#define   ASPEED_MDIO_CTRL_OP		GENMASK(27, 26)
22#define     MDIO_C22_OP_WRITE		0b01
23#define     MDIO_C22_OP_READ		0b10
24#define   ASPEED_MDIO_CTRL_PHYAD	GENMASK(25, 21)
25#define   ASPEED_MDIO_CTRL_REGAD	GENMASK(20, 16)
26#define   ASPEED_MDIO_CTRL_MIIWDATA	GENMASK(15, 0)
27
28#define ASPEED_MDIO_DATA		0x4
29#define   ASPEED_MDIO_DATA_MDC_THRES	GENMASK(31, 24)
30#define   ASPEED_MDIO_DATA_MDIO_EDGE	BIT(23)
31#define   ASPEED_MDIO_DATA_MDIO_LATCH	GENMASK(22, 20)
32#define   ASPEED_MDIO_DATA_IDLE		BIT(16)
33#define   ASPEED_MDIO_DATA_MIIRDATA	GENMASK(15, 0)
34
35#define ASPEED_MDIO_INTERVAL_US		100
36#define ASPEED_MDIO_TIMEOUT_US		(ASPEED_MDIO_INTERVAL_US * 10)
37
38struct aspeed_mdio {
39	void __iomem *base;
40};
41
42static int aspeed_mdio_read(struct mii_bus *bus, int addr, int regnum)
43{
44	struct aspeed_mdio *ctx = bus->priv;
45	u32 ctrl;
46	u32 data;
47	int rc;
48
49	dev_dbg(&bus->dev, "%s: addr: %d, regnum: %d\n", __func__, addr,
50		regnum);
51
52	/* Just clause 22 for the moment */
53	if (regnum & MII_ADDR_C45)
54		return -EOPNOTSUPP;
55
56	ctrl = ASPEED_MDIO_CTRL_FIRE
57		| FIELD_PREP(ASPEED_MDIO_CTRL_ST, ASPEED_MDIO_CTRL_ST_C22)
58		| FIELD_PREP(ASPEED_MDIO_CTRL_OP, MDIO_C22_OP_READ)
59		| FIELD_PREP(ASPEED_MDIO_CTRL_PHYAD, addr)
60		| FIELD_PREP(ASPEED_MDIO_CTRL_REGAD, regnum);
61
62	iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
63
64	rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
65				!(ctrl & ASPEED_MDIO_CTRL_FIRE),
66				ASPEED_MDIO_INTERVAL_US,
67				ASPEED_MDIO_TIMEOUT_US);
68	if (rc < 0)
69		return rc;
70
71	rc = readl_poll_timeout(ctx->base + ASPEED_MDIO_DATA, data,
72				data & ASPEED_MDIO_DATA_IDLE,
73				ASPEED_MDIO_INTERVAL_US,
74				ASPEED_MDIO_TIMEOUT_US);
75	if (rc < 0)
76		return rc;
77
78	return FIELD_GET(ASPEED_MDIO_DATA_MIIRDATA, data);
79}
80
81static int aspeed_mdio_write(struct mii_bus *bus, int addr, int regnum, u16 val)
82{
83	struct aspeed_mdio *ctx = bus->priv;
84	u32 ctrl;
85
86	dev_dbg(&bus->dev, "%s: addr: %d, regnum: %d, val: 0x%x\n",
87		__func__, addr, regnum, val);
88
89	/* Just clause 22 for the moment */
90	if (regnum & MII_ADDR_C45)
91		return -EOPNOTSUPP;
92
93	ctrl = ASPEED_MDIO_CTRL_FIRE
94		| FIELD_PREP(ASPEED_MDIO_CTRL_ST, ASPEED_MDIO_CTRL_ST_C22)
95		| FIELD_PREP(ASPEED_MDIO_CTRL_OP, MDIO_C22_OP_WRITE)
96		| FIELD_PREP(ASPEED_MDIO_CTRL_PHYAD, addr)
97		| FIELD_PREP(ASPEED_MDIO_CTRL_REGAD, regnum)
98		| FIELD_PREP(ASPEED_MDIO_CTRL_MIIWDATA, val);
99
100	iowrite32(ctrl, ctx->base + ASPEED_MDIO_CTRL);
101
102	return readl_poll_timeout(ctx->base + ASPEED_MDIO_CTRL, ctrl,
103				  !(ctrl & ASPEED_MDIO_CTRL_FIRE),
104				  ASPEED_MDIO_INTERVAL_US,
105				  ASPEED_MDIO_TIMEOUT_US);
106}
107
108static int aspeed_mdio_probe(struct platform_device *pdev)
109{
110	struct aspeed_mdio *ctx;
111	struct mii_bus *bus;
112	int rc;
113
114	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*ctx));
115	if (!bus)
116		return -ENOMEM;
117
118	ctx = bus->priv;
119	ctx->base = devm_platform_ioremap_resource(pdev, 0);
120	if (IS_ERR(ctx->base))
121		return PTR_ERR(ctx->base);
122
123	bus->name = DRV_NAME;
124	snprintf(bus->id, MII_BUS_ID_SIZE, "%s%d", pdev->name, pdev->id);
125	bus->parent = &pdev->dev;
126	bus->read = aspeed_mdio_read;
127	bus->write = aspeed_mdio_write;
128
129	rc = of_mdiobus_register(bus, pdev->dev.of_node);
130	if (rc) {
131		dev_err(&pdev->dev, "Cannot register MDIO bus!\n");
132		return rc;
133	}
134
135	platform_set_drvdata(pdev, bus);
136
137	return 0;
138}
139
140static int aspeed_mdio_remove(struct platform_device *pdev)
141{
142	mdiobus_unregister(platform_get_drvdata(pdev));
143
144	return 0;
145}
146
147static const struct of_device_id aspeed_mdio_of_match[] = {
148	{ .compatible = "aspeed,ast2600-mdio", },
149	{ },
150};
151
152static struct platform_driver aspeed_mdio_driver = {
153	.driver = {
154		.name = DRV_NAME,
155		.of_match_table = aspeed_mdio_of_match,
156	},
157	.probe = aspeed_mdio_probe,
158	.remove = aspeed_mdio_remove,
159};
160
161module_platform_driver(aspeed_mdio_driver);
162
163MODULE_AUTHOR("Andrew Jeffery <andrew@aj.id.au>");
164MODULE_LICENSE("GPL");
165