tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Driver for the MDIO interface of Marvell network interfaces.
3 *
4 * Since the MDIO interface of Marvell network interfaces is shared
5 * between all network interfaces, having a single driver allows to
6 * handle concurrent accesses properly (you may have four Ethernet
7 * ports, but they in fact share the same SMI interface to access
8 * the MDIO bus). This driver is currently used by the mvneta and
9 * mv643xx_eth drivers.
10 *
11 * Copyright (C) 2012 Marvell
12 *
13 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
14 *
15 * This file is licensed under the terms of the GNU General Public
16 * License version 2. This program is licensed "as is" without any
17 * warranty of any kind, whether express or implied.
18 */
19
20#include <linux/kernel.h>
21#include <linux/module.h>
22#include <linux/mutex.h>
23#include <linux/phy.h>
24#include <linux/interrupt.h>
25#include <linux/platform_device.h>
26#include <linux/delay.h>
27#include <linux/io.h>
28#include <linux/clk.h>
29#include <linux/of_mdio.h>
30#include <linux/sched.h>
31#include <linux/wait.h>
32
33#define MVMDIO_SMI_DATA_SHIFT 0
34#define MVMDIO_SMI_PHY_ADDR_SHIFT 16
35#define MVMDIO_SMI_PHY_REG_SHIFT 21
36#define MVMDIO_SMI_READ_OPERATION BIT(26)
37#define MVMDIO_SMI_WRITE_OPERATION 0
38#define MVMDIO_SMI_READ_VALID BIT(27)
39#define MVMDIO_SMI_BUSY BIT(28)
40#define MVMDIO_ERR_INT_CAUSE 0x007C
41#define MVMDIO_ERR_INT_SMI_DONE 0x00000010
42#define MVMDIO_ERR_INT_MASK 0x0080
43
44/*
45 * SMI Timeout measurements:
46 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
47 * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled)
48 */
49#define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */
50#define MVMDIO_SMI_POLL_INTERVAL_MIN 45
51#define MVMDIO_SMI_POLL_INTERVAL_MAX 55
52
53struct orion_mdio_dev {
54 struct mutex lock;
55 void __iomem *regs;
56 struct clk *clk;
57 /*
58 * If we have access to the error interrupt pin (which is
59 * somewhat misnamed as it not only reflects internal errors
60 * but also reflects SMI completion), use that to wait for
61 * SMI access completion instead of polling the SMI busy bit.
62 */
63 int err_interrupt;
64 wait_queue_head_t smi_busy_wait;
65};
66
67static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
68{
69 return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
70}
71
72/* Wait for the SMI unit to be ready for another operation
73 */
74static int orion_mdio_wait_ready(struct mii_bus *bus)
75{
76 struct orion_mdio_dev *dev = bus->priv;
77 unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
78 unsigned long end = jiffies + timeout;
79 int timedout = 0;
80
81 while (1) {
82 if (orion_mdio_smi_is_done(dev))
83 return 0;
84 else if (timedout)
85 break;
86
87 if (dev->err_interrupt <= 0) {
88 usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
89 MVMDIO_SMI_POLL_INTERVAL_MAX);
90
91 if (time_is_before_jiffies(end))
92 ++timedout;
93 } else {
94 /* wait_event_timeout does not guarantee a delay of at
95 * least one whole jiffie, so timeout must be no less
96 * than two.
97 */
98 if (timeout < 2)
99 timeout = 2;
100 wait_event_timeout(dev->smi_busy_wait,
101 orion_mdio_smi_is_done(dev),
102 timeout);
103
104 ++timedout;
105 }
106 }
107
108 dev_err(bus->parent, "Timeout: SMI busy for too long\n");
109 return -ETIMEDOUT;
110}
111
112static int orion_mdio_read(struct mii_bus *bus, int mii_id,
113 int regnum)
114{
115 struct orion_mdio_dev *dev = bus->priv;
116 u32 val;
117 int ret;
118
119 mutex_lock(&dev->lock);
120
121 ret = orion_mdio_wait_ready(bus);
122 if (ret < 0)
123 goto out;
124
125 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
126 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
127 MVMDIO_SMI_READ_OPERATION),
128 dev->regs);
129
130 ret = orion_mdio_wait_ready(bus);
131 if (ret < 0)
132 goto out;
133
134 val = readl(dev->regs);
135 if (!(val & MVMDIO_SMI_READ_VALID)) {
136 dev_err(bus->parent, "SMI bus read not valid\n");
137 ret = -ENODEV;
138 goto out;
139 }
140
141 ret = val & 0xFFFF;
142out:
143 mutex_unlock(&dev->lock);
144 return ret;
145}
146
147static int orion_mdio_write(struct mii_bus *bus, int mii_id,
148 int regnum, u16 value)
149{
150 struct orion_mdio_dev *dev = bus->priv;
151 int ret;
152
153 mutex_lock(&dev->lock);
154
155 ret = orion_mdio_wait_ready(bus);
156 if (ret < 0)
157 goto out;
158
159 writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
160 (regnum << MVMDIO_SMI_PHY_REG_SHIFT) |
161 MVMDIO_SMI_WRITE_OPERATION |
162 (value << MVMDIO_SMI_DATA_SHIFT)),
163 dev->regs);
164
165out:
166 mutex_unlock(&dev->lock);
167 return ret;
168}
169
170static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
171{
172 struct orion_mdio_dev *dev = dev_id;
173
174 if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
175 MVMDIO_ERR_INT_SMI_DONE) {
176 writel(~MVMDIO_ERR_INT_SMI_DONE,
177 dev->regs + MVMDIO_ERR_INT_CAUSE);
178 wake_up(&dev->smi_busy_wait);
179 return IRQ_HANDLED;
180 }
181
182 return IRQ_NONE;
183}
184
185static int orion_mdio_probe(struct platform_device *pdev)
186{
187 struct resource *r;
188 struct mii_bus *bus;
189 struct orion_mdio_dev *dev;
190 int ret;
191
192 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
193 if (!r) {
194 dev_err(&pdev->dev, "No SMI register address given\n");
195 return -ENODEV;
196 }
197
198 bus = devm_mdiobus_alloc_size(&pdev->dev,
199 sizeof(struct orion_mdio_dev));
200 if (!bus)
201 return -ENOMEM;
202
203 bus->name = "orion_mdio_bus";
204 bus->read = orion_mdio_read;
205 bus->write = orion_mdio_write;
206 snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
207 dev_name(&pdev->dev));
208 bus->parent = &pdev->dev;
209
210 dev = bus->priv;
211 dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
212 if (!dev->regs) {
213 dev_err(&pdev->dev, "Unable to remap SMI register\n");
214 return -ENODEV;
215 }
216
217 init_waitqueue_head(&dev->smi_busy_wait);
218
219 dev->clk = devm_clk_get(&pdev->dev, NULL);
220 if (!IS_ERR(dev->clk))
221 clk_prepare_enable(dev->clk);
222
223 dev->err_interrupt = platform_get_irq(pdev, 0);
224 if (dev->err_interrupt > 0) {
225 ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
226 orion_mdio_err_irq,
227 IRQF_SHARED, pdev->name, dev);
228 if (ret)
229 goto out_mdio;
230
231 writel(MVMDIO_ERR_INT_SMI_DONE,
232 dev->regs + MVMDIO_ERR_INT_MASK);
233
234 } else if (dev->err_interrupt == -EPROBE_DEFER) {
235 return -EPROBE_DEFER;
236 }
237
238 mutex_init(&dev->lock);
239
240 if (pdev->dev.of_node)
241 ret = of_mdiobus_register(bus, pdev->dev.of_node);
242 else
243 ret = mdiobus_register(bus);
244 if (ret < 0) {
245 dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
246 goto out_mdio;
247 }
248
249 platform_set_drvdata(pdev, bus);
250
251 return 0;
252
253out_mdio:
254 if (!IS_ERR(dev->clk))
255 clk_disable_unprepare(dev->clk);
256 return ret;
257}
258
259static int orion_mdio_remove(struct platform_device *pdev)
260{
261 struct mii_bus *bus = platform_get_drvdata(pdev);
262 struct orion_mdio_dev *dev = bus->priv;
263
264 writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
265 mdiobus_unregister(bus);
266 if (!IS_ERR(dev->clk))
267 clk_disable_unprepare(dev->clk);
268
269 return 0;
270}
271
272static const struct of_device_id orion_mdio_match[] = {
273 { .compatible = "marvell,orion-mdio" },
274 { }
275};
276MODULE_DEVICE_TABLE(of, orion_mdio_match);
277
278static struct platform_driver orion_mdio_driver = {
279 .probe = orion_mdio_probe,
280 .remove = orion_mdio_remove,
281 .driver = {
282 .name = "orion-mdio",
283 .of_match_table = orion_mdio_match,
284 },
285};
286
287module_platform_driver(orion_mdio_driver);
288
289MODULE_DESCRIPTION("Marvell MDIO interface driver");
290MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
291MODULE_LICENSE("GPL");
292MODULE_ALIAS("platform:orion-mdio");