summaryrefslogtreecommitdiffstats
path: root/drivers/net/ethernet/marvell/mvmdio.c
blob: b161a525fc5bd8accb44b002b64776f05d8d0319 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
/*
 * Driver for the MDIO interface of Marvell network interfaces.
 *
 * Since the MDIO interface of Marvell network interfaces is shared
 * between all network interfaces, having a single driver allows to
 * handle concurrent accesses properly (you may have four Ethernet
 * ports, but they in fact share the same SMI interface to access
 * the MDIO bus). This driver is currently used by the mvneta and
 * mv643xx_eth drivers.
 *
 * Copyright (C) 2012 Marvell
 *
 * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/phy.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/of_mdio.h>
#include <linux/sched.h>
#include <linux/wait.h>

#define MVMDIO_SMI_DATA_SHIFT              0
#define MVMDIO_SMI_PHY_ADDR_SHIFT          16
#define MVMDIO_SMI_PHY_REG_SHIFT           21
#define MVMDIO_SMI_READ_OPERATION          BIT(26)
#define MVMDIO_SMI_WRITE_OPERATION         0
#define MVMDIO_SMI_READ_VALID              BIT(27)
#define MVMDIO_SMI_BUSY                    BIT(28)
#define MVMDIO_ERR_INT_CAUSE		   0x007C
#define  MVMDIO_ERR_INT_SMI_DONE	   0x00000010
#define MVMDIO_ERR_INT_MASK		   0x0080

/*
 * SMI Timeout measurements:
 * - Kirkwood 88F6281 (Globalscale Dreamplug): 45us to 95us (Interrupt)
 * - Armada 370       (Globalscale Mirabox):   41us to 43us (Polled)
 */
#define MVMDIO_SMI_TIMEOUT		   1000 /* 1000us = 1ms */
#define MVMDIO_SMI_POLL_INTERVAL_MIN	   45
#define MVMDIO_SMI_POLL_INTERVAL_MAX	   55

struct orion_mdio_dev {
	struct mutex lock;
	void __iomem *regs;
	struct clk *clk;
	/*
	 * If we have access to the error interrupt pin (which is
	 * somewhat misnamed as it not only reflects internal errors
	 * but also reflects SMI completion), use that to wait for
	 * SMI access completion instead of polling the SMI busy bit.
	 */
	int err_interrupt;
	wait_queue_head_t smi_busy_wait;
};

static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
{
	return !(readl(dev->regs) & MVMDIO_SMI_BUSY);
}

/* Wait for the SMI unit to be ready for another operation
 */
static int orion_mdio_wait_ready(struct mii_bus *bus)
{
	struct orion_mdio_dev *dev = bus->priv;
	unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT);
	unsigned long end = jiffies + timeout;
	int timedout = 0;

	while (1) {
	        if (orion_mdio_smi_is_done(dev))
			return 0;
	        else if (timedout)
			break;

	        if (dev->err_interrupt <= 0) {
			usleep_range(MVMDIO_SMI_POLL_INTERVAL_MIN,
				     MVMDIO_SMI_POLL_INTERVAL_MAX);

			if (time_is_before_jiffies(end))
				++timedout;
	        } else {
			/* wait_event_timeout does not guarantee a delay of at
			 * least one whole jiffie, so timeout must be no less
			 * than two.
			 */
			if (timeout < 2)
				timeout = 2;
			wait_event_timeout(dev->smi_busy_wait,
				           orion_mdio_smi_is_done(dev),
				           timeout);

			++timedout;
	        }
	}

	dev_err(bus->parent, "Timeout: SMI busy for too long\n");
	return  -ETIMEDOUT;
}

static int orion_mdio_read(struct mii_bus *bus, int mii_id,
			   int regnum)
{
	struct orion_mdio_dev *dev = bus->priv;
	u32 val;
	int ret;

	mutex_lock(&dev->lock);

	ret = orion_mdio_wait_ready(bus);
	if (ret < 0)
		goto out;

	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
		MVMDIO_SMI_READ_OPERATION),
	       dev->regs);

	ret = orion_mdio_wait_ready(bus);
	if (ret < 0)
		goto out;

	val = readl(dev->regs);
	if (!(val & MVMDIO_SMI_READ_VALID)) {
		dev_err(bus->parent, "SMI bus read not valid\n");
		ret = -ENODEV;
		goto out;
	}

	ret = val & 0xFFFF;
out:
	mutex_unlock(&dev->lock);
	return ret;
}

static int orion_mdio_write(struct mii_bus *bus, int mii_id,
			    int regnum, u16 value)
{
	struct orion_mdio_dev *dev = bus->priv;
	int ret;

	mutex_lock(&dev->lock);

	ret = orion_mdio_wait_ready(bus);
	if (ret < 0)
		goto out;

	writel(((mii_id << MVMDIO_SMI_PHY_ADDR_SHIFT) |
		(regnum << MVMDIO_SMI_PHY_REG_SHIFT)  |
		MVMDIO_SMI_WRITE_OPERATION            |
		(value << MVMDIO_SMI_DATA_SHIFT)),
	       dev->regs);

out:
	mutex_unlock(&dev->lock);
	return ret;
}

static irqreturn_t orion_mdio_err_irq(int irq, void *dev_id)
{
	struct orion_mdio_dev *dev = dev_id;

	if (readl(dev->regs + MVMDIO_ERR_INT_CAUSE) &
			MVMDIO_ERR_INT_SMI_DONE) {
		writel(~MVMDIO_ERR_INT_SMI_DONE,
				dev->regs + MVMDIO_ERR_INT_CAUSE);
		wake_up(&dev->smi_busy_wait);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static int orion_mdio_probe(struct platform_device *pdev)
{
	struct resource *r;
	struct mii_bus *bus;
	struct orion_mdio_dev *dev;
	int i, ret;

	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!r) {
		dev_err(&pdev->dev, "No SMI register address given\n");
		return -ENODEV;
	}

	bus = mdiobus_alloc_size(sizeof(struct orion_mdio_dev));
	if (!bus) {
		dev_err(&pdev->dev, "Cannot allocate MDIO bus\n");
		return -ENOMEM;
	}

	bus->name = "orion_mdio_bus";
	bus->read = orion_mdio_read;
	bus->write = orion_mdio_write;
	snprintf(bus->id, MII_BUS_ID_SIZE, "%s-mii",
		 dev_name(&pdev->dev));
	bus->parent = &pdev->dev;

	bus->irq = kmalloc(sizeof(int) * PHY_MAX_ADDR, GFP_KERNEL);
	if (!bus->irq) {
		mdiobus_free(bus);
		return -ENOMEM;
	}

	for (i = 0; i < PHY_MAX_ADDR; i++)
		bus->irq[i] = PHY_POLL;

	dev = bus->priv;
	dev->regs = devm_ioremap(&pdev->dev, r->start, resource_size(r));
	if (!dev->regs) {
		dev_err(&pdev->dev, "Unable to remap SMI register\n");
		ret = -ENODEV;
		goto out_mdio;
	}

	init_waitqueue_head(&dev->smi_busy_wait);

	dev->clk = devm_clk_get(&pdev->dev, NULL);
	if (!IS_ERR(dev->clk))
		clk_prepare_enable(dev->clk);

	dev->err_interrupt = platform_get_irq(pdev, 0);
	if (dev->err_interrupt != -ENXIO) {
		ret = devm_request_irq(&pdev->dev, dev->err_interrupt,
					orion_mdio_err_irq,
					IRQF_SHARED, pdev->name, dev);
		if (ret)
			goto out_mdio;

		writel(MVMDIO_ERR_INT_SMI_DONE,
			dev->regs + MVMDIO_ERR_INT_MASK);
	}

	mutex_init(&dev->lock);

	if (pdev->dev.of_node)
		ret = of_mdiobus_register(bus, pdev->dev.of_node);
	else
		ret = mdiobus_register(bus);
	if (ret < 0) {
		dev_err(&pdev->dev, "Cannot register MDIO bus (%d)\n", ret);
		goto out_mdio;
	}

	platform_set_drvdata(pdev, bus);

	return 0;

out_mdio:
	if (!IS_ERR(dev->clk))
		clk_disable_unprepare(dev->clk);
	kfree(bus->irq);
	mdiobus_free(bus);
	return ret;
}

static int orion_mdio_remove(struct platform_device *pdev)
{
	struct mii_bus *bus = platform_get_drvdata(pdev);
	struct orion_mdio_dev *dev = bus->priv;

	writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
	mdiobus_unregister(bus);
	kfree(bus->irq);
	mdiobus_free(bus);
	if (!IS_ERR(dev->clk))
		clk_disable_unprepare(dev->clk);

	return 0;
}

static const struct of_device_id orion_mdio_match[] = {
	{ .compatible = "marvell,orion-mdio" },
	{ }
};
MODULE_DEVICE_TABLE(of, orion_mdio_match);

static struct platform_driver orion_mdio_driver = {
	.probe = orion_mdio_probe,
	.remove = orion_mdio_remove,
	.driver = {
		.name = "orion-mdio",
		.of_match_table = orion_mdio_match,
	},
};

module_platform_driver(orion_mdio_driver);

MODULE_DESCRIPTION("Marvell MDIO interface driver");
MODULE_AUTHOR("Thomas Petazzoni <thomas.petazzoni@free-electrons.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:orion-mdio");