tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: (GPL-2.0 OR MIT)
2/*
3 * Driver for the MDIO interface of Microsemi network switches.
4 *
5 * Author: Alexandre Belloni <alexandre.belloni@bootlin.com>
6 * Copyright (c) 2017 Microsemi Corporation
7 */
8
9#include <linux/bitops.h>
10#include <linux/io.h>
11#include <linux/iopoll.h>
12#include <linux/kernel.h>
13#include <linux/module.h>
14#include <linux/of_mdio.h>
15#include <linux/phy.h>
16#include <linux/platform_device.h>
17
18#define MSCC_MIIM_REG_STATUS 0x0
19#define MSCC_MIIM_STATUS_STAT_PENDING BIT(2)
20#define MSCC_MIIM_STATUS_STAT_BUSY BIT(3)
21#define MSCC_MIIM_REG_CMD 0x8
22#define MSCC_MIIM_CMD_OPR_WRITE BIT(1)
23#define MSCC_MIIM_CMD_OPR_READ BIT(2)
24#define MSCC_MIIM_CMD_WRDATA_SHIFT 4
25#define MSCC_MIIM_CMD_REGAD_SHIFT 20
26#define MSCC_MIIM_CMD_PHYAD_SHIFT 25
27#define MSCC_MIIM_CMD_VLD BIT(31)
28#define MSCC_MIIM_REG_DATA 0xC
29#define MSCC_MIIM_DATA_ERROR (BIT(16) | BIT(17))
30
31#define MSCC_PHY_REG_PHY_CFG 0x0
32#define PHY_CFG_PHY_ENA (BIT(0) | BIT(1) | BIT(2) | BIT(3))
33#define PHY_CFG_PHY_COMMON_RESET BIT(4)
34#define PHY_CFG_PHY_RESET (BIT(5) | BIT(6) | BIT(7) | BIT(8))
35#define MSCC_PHY_REG_PHY_STATUS 0x4
36
37struct mscc_miim_dev {
38 void __iomem *regs;
39 void __iomem *phy_regs;
40};
41
42/* When high resolution timers aren't built-in: we can't use usleep_range() as
43 * we would sleep way too long. Use udelay() instead.
44 */
45#define mscc_readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
46({ \
47 if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS)) \
48 readl_poll_timeout_atomic(addr, val, cond, delay_us, \
49 timeout_us); \
50 readl_poll_timeout(addr, val, cond, delay_us, timeout_us); \
51})
52
53static int mscc_miim_wait_ready(struct mii_bus *bus)
54{
55 struct mscc_miim_dev *miim = bus->priv;
56 u32 val;
57
58 return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
59 !(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
60 10000);
61}
62
63static int mscc_miim_wait_pending(struct mii_bus *bus)
64{
65 struct mscc_miim_dev *miim = bus->priv;
66 u32 val;
67
68 return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
69 !(val & MSCC_MIIM_STATUS_STAT_PENDING),
70 50, 10000);
71}
72
73static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)
74{
75 struct mscc_miim_dev *miim = bus->priv;
76 u32 val;
77 int ret;
78
79 ret = mscc_miim_wait_pending(bus);
80 if (ret)
81 goto out;
82
83 writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
84 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) | MSCC_MIIM_CMD_OPR_READ,
85 miim->regs + MSCC_MIIM_REG_CMD);
86
87 ret = mscc_miim_wait_ready(bus);
88 if (ret)
89 goto out;
90
91 val = readl(miim->regs + MSCC_MIIM_REG_DATA);
92 if (val & MSCC_MIIM_DATA_ERROR) {
93 ret = -EIO;
94 goto out;
95 }
96
97 ret = val & 0xFFFF;
98out:
99 return ret;
100}
101
102static int mscc_miim_write(struct mii_bus *bus, int mii_id,
103 int regnum, u16 value)
104{
105 struct mscc_miim_dev *miim = bus->priv;
106 int ret;
107
108 ret = mscc_miim_wait_pending(bus);
109 if (ret < 0)
110 goto out;
111
112 writel(MSCC_MIIM_CMD_VLD | (mii_id << MSCC_MIIM_CMD_PHYAD_SHIFT) |
113 (regnum << MSCC_MIIM_CMD_REGAD_SHIFT) |
114 (value << MSCC_MIIM_CMD_WRDATA_SHIFT) |
115 MSCC_MIIM_CMD_OPR_WRITE,
116 miim->regs + MSCC_MIIM_REG_CMD);
117
118out:
119 return ret;
120}
121
122static int mscc_miim_reset(struct mii_bus *bus)
123{
124 struct mscc_miim_dev *miim = bus->priv;
125
126 if (miim->phy_regs) {
127 writel(0, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
128 writel(0x1ff, miim->phy_regs + MSCC_PHY_REG_PHY_CFG);
129 mdelay(500);
130 }
131
132 return 0;
133}
134
135static int mscc_miim_probe(struct platform_device *pdev)
136{
137 struct mscc_miim_dev *dev;
138 struct resource *res;
139 struct mii_bus *bus;
140 int ret;
141
142 bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*dev));
143 if (!bus)
144 return -ENOMEM;
145
146 bus->name = "mscc_miim";
147 bus->read = mscc_miim_read;
148 bus->write = mscc_miim_write;
149 bus->reset = mscc_miim_reset;
150 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii", dev_name(&pdev->dev));
151 bus->parent = &pdev->dev;
152
153 dev = bus->priv;
154 dev->regs = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
155 if (IS_ERR(dev->regs)) {
156 dev_err(&pdev->dev, "Unable to map MIIM registers\n");
157 return PTR_ERR(dev->regs);
158 }
159
160 /* This resource is optional */
161 res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
162 if (res) {
163 dev->phy_regs = devm_ioremap_resource(&pdev->dev, res);
164 if (IS_ERR(dev->phy_regs)) {
165 dev_err(&pdev->dev, "Unable to map internal phy registers\n");
166 return PTR_ERR(dev->phy_regs);
167 }
168 }
169
170 ret = of_mdiobus_register(bus, pdev->dev.of_node);
171 if (ret < 0) {
172 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
173 return ret;
174 }
175
176 platform_set_drvdata(pdev, bus);
177
178 return 0;
179}
180
181static int mscc_miim_remove(struct platform_device *pdev)
182{
183 struct mii_bus *bus = platform_get_drvdata(pdev);
184
185 mdiobus_unregister(bus);
186
187 return 0;
188}
189
190static const struct of_device_id mscc_miim_match[] = {
191 { .compatible = "mscc,ocelot-miim" },
192 { }
193};
194MODULE_DEVICE_TABLE(of, mscc_miim_match);
195
196static struct platform_driver mscc_miim_driver = {
197 .probe = mscc_miim_probe,
198 .remove = mscc_miim_remove,
199 .driver = {
200 .name = "mscc-miim",
201 .of_match_table = mscc_miim_match,
202 },
203};
204
205module_platform_driver(mscc_miim_driver);
206
207MODULE_DESCRIPTION("Microsemi MIIM driver");
208MODULE_AUTHOR("Alexandre Belloni <alexandre.belloni@bootlin.com>");
209MODULE_LICENSE("Dual MIT/GPL");