summaryrefslogtreecommitdiffstats
path: root/drivers/net/ethernet/ti/davinci_mdio.c
blob: e4e47088e26b98fe0118c16ae17da61ec0f07dde (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
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
/*
 * DaVinci MDIO Module driver
 *
 * Copyright (C) 2010 Texas Instruments.
 *
 * Shamelessly ripped out of davinci_emac.c, original copyrights follow:
 *
 * Copyright (C) 2009 Texas Instruments.
 *
 * ---------------------------------------------------------------------------
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 * ---------------------------------------------------------------------------
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/phy.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/davinci_emac.h>

/*
 * This timeout definition is a worst-case ultra defensive measure against
 * unexpected controller lock ups.  Ideally, we should never ever hit this
 * scenario in practice.
 */
#define MDIO_TIMEOUT		100 /* msecs */

#define PHY_REG_MASK		0x1f
#define PHY_ID_MASK		0x1f

#define DEF_OUT_FREQ		2200000		/* 2.2 MHz */

struct davinci_mdio_regs {
	u32	version;
	u32	control;
#define CONTROL_IDLE		BIT(31)
#define CONTROL_ENABLE		BIT(30)
#define CONTROL_MAX_DIV		(0xffff)

	u32	alive;
	u32	link;
	u32	linkintraw;
	u32	linkintmasked;
	u32	__reserved_0[2];
	u32	userintraw;
	u32	userintmasked;
	u32	userintmaskset;
	u32	userintmaskclr;
	u32	__reserved_1[20];

	struct {
		u32	access;
#define USERACCESS_GO		BIT(31)
#define USERACCESS_WRITE	BIT(30)
#define USERACCESS_ACK		BIT(29)
#define USERACCESS_READ		(0)
#define USERACCESS_DATA		(0xffff)

		u32	physel;
	}	user[0];
};

struct mdio_platform_data default_pdata = {
	.bus_freq = DEF_OUT_FREQ,
};

struct davinci_mdio_data {
	struct mdio_platform_data pdata;
	struct davinci_mdio_regs __iomem *regs;
	spinlock_t	lock;
	struct clk	*clk;
	struct device	*dev;
	struct mii_bus	*bus;
	bool		suspended;
	unsigned long	access_time; /* jiffies */
};

static void __davinci_mdio_reset(struct davinci_mdio_data *data)
{
	u32 mdio_in, div, mdio_out_khz, access_time;

	mdio_in = clk_get_rate(data->clk);
	div = (mdio_in / data->pdata.bus_freq) - 1;
	if (div > CONTROL_MAX_DIV)
		div = CONTROL_MAX_DIV;

	/* set enable and clock divider */
	__raw_writel(div | CONTROL_ENABLE, &data->regs->control);

	/*
	 * One mdio transaction consists of:
	 *	32 bits of preamble
	 *	32 bits of transferred data
	 *	24 bits of bus yield (not needed unless shared?)
	 */
	mdio_out_khz = mdio_in / (1000 * (div + 1));
	access_time  = (88 * 1000) / mdio_out_khz;

	/*
	 * In the worst case, we could be kicking off a user-access immediately
	 * after the mdio bus scan state-machine triggered its own read.  If
	 * so, our request could get deferred by one access cycle.  We
	 * defensively allow for 4 access cycles.
	 */
	data->access_time = usecs_to_jiffies(access_time * 4);
	if (!data->access_time)
		data->access_time = 1;
}

static int davinci_mdio_reset(struct mii_bus *bus)
{
	struct davinci_mdio_data *data = bus->priv;
	u32 phy_mask, ver;

	__davinci_mdio_reset(data);

	/* wait for scan logic to settle */
	msleep(PHY_MAX_ADDR * data->access_time);

	/* dump hardware version info */
	ver = __raw_readl(&data->regs->version);
	dev_info(data->dev, "davinci mdio revision %d.%d\n",
		 (ver >> 8) & 0xff, ver & 0xff);

	/* get phy mask from the alive register */
	phy_mask = __raw_readl(&data->regs->alive);
	if (phy_mask) {
		/* restrict mdio bus to live phys only */
		dev_info(data->dev, "detected phy mask %x\n", ~phy_mask);
		phy_mask = ~phy_mask;
	} else {
		/* desperately scan all phys */
		dev_warn(data->dev, "no live phy, scanning all\n");
		phy_mask = 0;
	}
	data->bus->phy_mask = phy_mask;

	return 0;
}

/* wait until hardware is ready for another user access */
static inline int wait_for_user_access(struct davinci_mdio_data *data)
{
	struct davinci_mdio_regs __iomem *regs = data->regs;
	unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);
	u32 reg;

	while (time_after(timeout, jiffies)) {
		reg = __raw_readl(&regs->user[0].access);
		if ((reg & USERACCESS_GO) == 0)
			return 0;

		reg = __raw_readl(&regs->control);
		if ((reg & CONTROL_IDLE) == 0)
			continue;

		/*
		 * An emac soft_reset may have clobbered the mdio controller's
		 * state machine.  We need to reset and retry the current
		 * operation
		 */
		dev_warn(data->dev, "resetting idled controller\n");
		__davinci_mdio_reset(data);
		return -EAGAIN;
	}

	reg = __raw_readl(&regs->user[0].access);
	if ((reg & USERACCESS_GO) == 0)
		return 0;

	dev_err(data->dev, "timed out waiting for user access\n");
	return -ETIMEDOUT;
}

/* wait until hardware state machine is idle */
static inline int wait_for_idle(struct davinci_mdio_data *data)
{
	struct davinci_mdio_regs __iomem *regs = data->regs;
	unsigned long timeout = jiffies + msecs_to_jiffies(MDIO_TIMEOUT);

	while (time_after(timeout, jiffies)) {
		if (__raw_readl(&regs->control) & CONTROL_IDLE)
			return 0;
	}
	dev_err(data->dev, "timed out waiting for idle\n");
	return -ETIMEDOUT;
}

static int davinci_mdio_read(struct mii_bus *bus, int phy_id, int phy_reg)
{
	struct davinci_mdio_data *data = bus->priv;
	u32 reg;
	int ret;

	if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
		return -EINVAL;

	spin_lock(&data->lock);

	if (data->suspended) {
		spin_unlock(&data->lock);
		return -ENODEV;
	}

	reg = (USERACCESS_GO | USERACCESS_READ | (phy_reg << 21) |
	       (phy_id << 16));

	while (1) {
		ret = wait_for_user_access(data);
		if (ret == -EAGAIN)
			continue;
		if (ret < 0)
			break;

		__raw_writel(reg, &data->regs->user[0].access);

		ret = wait_for_user_access(data);
		if (ret == -EAGAIN)
			continue;
		if (ret < 0)
			break;

		reg = __raw_readl(&data->regs->user[0].access);
		ret = (reg & USERACCESS_ACK) ? (reg & USERACCESS_DATA) : -EIO;
		break;
	}

	spin_unlock(&data->lock);

	return ret;
}

static int davinci_mdio_write(struct mii_bus *bus, int phy_id,
			      int phy_reg, u16 phy_data)
{
	struct davinci_mdio_data *data = bus->priv;
	u32 reg;
	int ret;

	if (phy_reg & ~PHY_REG_MASK || phy_id & ~PHY_ID_MASK)
		return -EINVAL;

	spin_lock(&data->lock);

	if (data->suspended) {
		spin_unlock(&data->lock);
		return -ENODEV;
	}

	reg = (USERACCESS_GO | USERACCESS_WRITE | (phy_reg << 21) |
		   (phy_id << 16) | (phy_data & USERACCESS_DATA));

	while (1) {
		ret = wait_for_user_access(data);
		if (ret == -EAGAIN)
			continue;
		if (ret < 0)
			break;

		__raw_writel(reg, &data->regs->user[0].access);

		ret = wait_for_user_access(data);
		if (ret == -EAGAIN)
			continue;
		break;
	}

	spin_unlock(&data->lock);

	return 0;
}

static int __devinit davinci_mdio_probe(struct platform_device *pdev)
{
	struct mdio_platform_data *pdata = pdev->dev.platform_data;
	struct device *dev = &pdev->dev;
	struct davinci_mdio_data *data;
	struct resource *res;
	struct phy_device *phy;
	int ret, addr;

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (!data) {
		dev_err(dev, "failed to alloc device data\n");
		return -ENOMEM;
	}

	data->pdata = pdata ? (*pdata) : default_pdata;

	data->bus = mdiobus_alloc();
	if (!data->bus) {
		dev_err(dev, "failed to alloc mii bus\n");
		ret = -ENOMEM;
		goto bail_out;
	}

	data->bus->name		= dev_name(dev);
	data->bus->read		= davinci_mdio_read,
	data->bus->write	= davinci_mdio_write,
	data->bus->reset	= davinci_mdio_reset,
	data->bus->parent	= dev;
	data->bus->priv		= data;
	snprintf(data->bus->id, MII_BUS_ID_SIZE, "%s-%x",
		pdev->name, pdev->id);

	data->clk = clk_get(dev, NULL);
	if (IS_ERR(data->clk)) {
		dev_err(dev, "failed to get device clock\n");
		ret = PTR_ERR(data->clk);
		data->clk = NULL;
		goto bail_out;
	}

	clk_enable(data->clk);

	dev_set_drvdata(dev, data);
	data->dev = dev;
	spin_lock_init(&data->lock);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res) {
		dev_err(dev, "could not find register map resource\n");
		ret = -ENOENT;
		goto bail_out;
	}

	res = devm_request_mem_region(dev, res->start, resource_size(res),
					    dev_name(dev));
	if (!res) {
		dev_err(dev, "could not allocate register map resource\n");
		ret = -ENXIO;
		goto bail_out;
	}

	data->regs = devm_ioremap_nocache(dev, res->start, resource_size(res));
	if (!data->regs) {
		dev_err(dev, "could not map mdio registers\n");
		ret = -ENOMEM;
		goto bail_out;
	}

	/* register the mii bus */
	ret = mdiobus_register(data->bus);
	if (ret)
		goto bail_out;

	/* scan and dump the bus */
	for (addr = 0; addr < PHY_MAX_ADDR; addr++) {
		phy = data->bus->phy_map[addr];
		if (phy) {
			dev_info(dev, "phy[%d]: device %s, driver %s\n",
				 phy->addr, dev_name(&phy->dev),
				 phy->drv ? phy->drv->name : "unknown");
		}
	}

	return 0;

bail_out:
	if (data->bus)
		mdiobus_free(data->bus);

	if (data->clk) {
		clk_disable(data->clk);
		clk_put(data->clk);
	}

	kfree(data);

	return ret;
}

static int __devexit davinci_mdio_remove(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct davinci_mdio_data *data = dev_get_drvdata(dev);

	if (data->bus)
		mdiobus_free(data->bus);

	if (data->clk) {
		clk_disable(data->clk);
		clk_put(data->clk);
	}

	dev_set_drvdata(dev, NULL);

	kfree(data);

	return 0;
}

static int davinci_mdio_suspend(struct device *dev)
{
	struct davinci_mdio_data *data = dev_get_drvdata(dev);
	u32 ctrl;

	spin_lock(&data->lock);

	/* shutdown the scan state machine */
	ctrl = __raw_readl(&data->regs->control);
	ctrl &= ~CONTROL_ENABLE;
	__raw_writel(ctrl, &data->regs->control);
	wait_for_idle(data);

	if (data->clk)
		clk_disable(data->clk);

	data->suspended = true;
	spin_unlock(&data->lock);

	return 0;
}

static int davinci_mdio_resume(struct device *dev)
{
	struct davinci_mdio_data *data = dev_get_drvdata(dev);
	u32 ctrl;

	spin_lock(&data->lock);
	if (data->clk)
		clk_enable(data->clk);

	/* restart the scan state machine */
	ctrl = __raw_readl(&data->regs->control);
	ctrl |= CONTROL_ENABLE;
	__raw_writel(ctrl, &data->regs->control);

	data->suspended = false;
	spin_unlock(&data->lock);

	return 0;
}

static const struct dev_pm_ops davinci_mdio_pm_ops = {
	.suspend	= davinci_mdio_suspend,
	.resume		= davinci_mdio_resume,
};

static struct platform_driver davinci_mdio_driver = {
	.driver = {
		.name	 = "davinci_mdio",
		.owner	 = THIS_MODULE,
		.pm	 = &davinci_mdio_pm_ops,
	},
	.probe = davinci_mdio_probe,
	.remove = __devexit_p(davinci_mdio_remove),
};

static int __init davinci_mdio_init(void)
{
	return platform_driver_register(&davinci_mdio_driver);
}
device_initcall(davinci_mdio_init);

static void __exit davinci_mdio_exit(void)
{
	platform_driver_unregister(&davinci_mdio_driver);
}
module_exit(davinci_mdio_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("DaVinci MDIO driver");
OpenPOWER on IntegriCloud