aboutsummaryrefslogtreecommitdiff
path: root/drivers/ptp/ptp_ixp46x.c
blob: 4a08727fcaf39b55f409c005863603215c9b27cb (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
/*
 * PTP 1588 clock using the IXP46X
 *
 * Copyright (C) 2010 OMICRON electronics GmbH
 *
 *  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/device.h>
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/kernel.h>
#include <linux/module.h>

#include <linux/ptp_clock_kernel.h>
#include <mach/ixp46x_ts.h>

#define DRIVER		"ptp_ixp46x"
#define N_EXT_TS	2
#define MASTER_GPIO	8
#define MASTER_IRQ	25
#define SLAVE_GPIO	7
#define SLAVE_IRQ	24

struct ixp_clock {
	struct ixp46x_ts_regs *regs;
	struct ptp_clock *ptp_clock;
	struct ptp_clock_info caps;
	int exts0_enabled;
	int exts1_enabled;
};

DEFINE_SPINLOCK(register_lock);

/*
 * Register access functions
 */

static u64 ixp_systime_read(struct ixp46x_ts_regs *regs)
{
	u64 ns;
	u32 lo, hi;

	lo = __raw_readl(&regs->systime_lo);
	hi = __raw_readl(&regs->systime_hi);

	ns = ((u64) hi) << 32;
	ns |= lo;
	ns <<= TICKS_NS_SHIFT;

	return ns;
}

static void ixp_systime_write(struct ixp46x_ts_regs *regs, u64 ns)
{
	u32 hi, lo;

	ns >>= TICKS_NS_SHIFT;
	hi = ns >> 32;
	lo = ns & 0xffffffff;

	__raw_writel(lo, &regs->systime_lo);
	__raw_writel(hi, &regs->systime_hi);
}

/*
 * Interrupt service routine
 */

static irqreturn_t isr(int irq, void *priv)
{
	struct ixp_clock *ixp_clock = priv;
	struct ixp46x_ts_regs *regs = ixp_clock->regs;
	struct ptp_clock_event event;
	u32 ack = 0, lo, hi, val;

	val = __raw_readl(&regs->event);

	if (val & TSER_SNS) {
		ack |= TSER_SNS;
		if (ixp_clock->exts0_enabled) {
			hi = __raw_readl(&regs->asms_hi);
			lo = __raw_readl(&regs->asms_lo);
			event.type = PTP_CLOCK_EXTTS;
			event.index = 0;
			event.timestamp = ((u64) hi) << 32;
			event.timestamp |= lo;
			event.timestamp <<= TICKS_NS_SHIFT;
			ptp_clock_event(ixp_clock->ptp_clock, &event);
		}
	}

	if (val & TSER_SNM) {
		ack |= TSER_SNM;
		if (ixp_clock->exts1_enabled) {
			hi = __raw_readl(&regs->amms_hi);
			lo = __raw_readl(&regs->amms_lo);
			event.type = PTP_CLOCK_EXTTS;
			event.index = 1;
			event.timestamp = ((u64) hi) << 32;
			event.timestamp |= lo;
			event.timestamp <<= TICKS_NS_SHIFT;
			ptp_clock_event(ixp_clock->ptp_clock, &event);
		}
	}

	if (val & TTIPEND)
		ack |= TTIPEND; /* this bit seems to be always set */

	if (ack) {
		__raw_writel(ack, &regs->event);
		return IRQ_HANDLED;
	} else
		return IRQ_NONE;
}

/*
 * PTP clock operations
 */

static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
{
	u64 adj;
	u32 diff, addend;
	int neg_adj = 0;
	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
	struct ixp46x_ts_regs *regs = ixp_clock->regs;

	if (ppb < 0) {
		neg_adj = 1;
		ppb = -ppb;
	}
	addend = DEFAULT_ADDEND;
	adj = addend;
	adj *= ppb;
	diff = div_u64(adj, 1000000000ULL);

	addend = neg_adj ? addend - diff : addend + diff;

	__raw_writel(addend, &regs->addend);

	return 0;
}

static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
{
	s64 now;
	unsigned long flags;
	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
	struct ixp46x_ts_regs *regs = ixp_clock->regs;

	spin_lock_irqsave(&register_lock, flags);

	now = ixp_systime_read(regs);
	now += delta;
	ixp_systime_write(regs, now);

	spin_unlock_irqrestore(&register_lock, flags);

	return 0;
}

static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec *ts)
{
	u64 ns;
	u32 remainder;
	unsigned long flags;
	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
	struct ixp46x_ts_regs *regs = ixp_clock->regs;

	spin_lock_irqsave(&register_lock, flags);

	ns = ixp_systime_read(regs);

	spin_unlock_irqrestore(&register_lock, flags);

	ts->tv_sec = div_u64_rem(ns, 1000000000, &remainder);
	ts->tv_nsec = remainder;
	return 0;
}

static int ptp_ixp_settime(struct ptp_clock_info *ptp,
			   const struct timespec *ts)
{
	u64 ns;
	unsigned long flags;
	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
	struct ixp46x_ts_regs *regs = ixp_clock->regs;

	ns = ts->tv_sec * 1000000000ULL;
	ns += ts->tv_nsec;

	spin_lock_irqsave(&register_lock, flags);

	ixp_systime_write(regs, ns);

	spin_unlock_irqrestore(&register_lock, flags);

	return 0;
}

static int ptp_ixp_enable(struct ptp_clock_info *ptp,
			  struct ptp_clock_request *rq, int on)
{
	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);

	switch (rq->type) {
	case PTP_CLK_REQ_EXTTS:
		switch (rq->extts.index) {
		case 0:
			ixp_clock->exts0_enabled = on ? 1 : 0;
			break;
		case 1:
			ixp_clock->exts1_enabled = on ? 1 : 0;
			break;
		default:
			return -EINVAL;
		}
		return 0;
	default:
		break;
	}

	return -EOPNOTSUPP;
}

static struct ptp_clock_info ptp_ixp_caps = {
	.owner		= THIS_MODULE,
	.name		= "IXP46X timer",
	.max_adj	= 66666655,
	.n_ext_ts	= N_EXT_TS,
	.pps		= 0,
	.adjfreq	= ptp_ixp_adjfreq,
	.adjtime	= ptp_ixp_adjtime,
	.gettime	= ptp_ixp_gettime,
	.settime	= ptp_ixp_settime,
	.enable		= ptp_ixp_enable,
};

/* module operations */

static struct ixp_clock ixp_clock;

static int setup_interrupt(int gpio)
{
	int irq;
	int err;

	err = gpio_request(gpio, "ixp4-ptp");
	if (err)
		return err;

	err = gpio_direction_input(gpio);
	if (err)
		return err;

	irq = gpio_to_irq(gpio);

	if (NO_IRQ == irq)
		return NO_IRQ;

	if (irq_set_irq_type(irq, IRQF_TRIGGER_FALLING)) {
		pr_err("cannot set trigger type for irq %d\n", irq);
		return NO_IRQ;
	}

	if (request_irq(irq, isr, 0, DRIVER, &ixp_clock)) {
		pr_err("request_irq failed for irq %d\n", irq);
		return NO_IRQ;
	}

	return irq;
}

static void __exit ptp_ixp_exit(void)
{
	free_irq(MASTER_IRQ, &ixp_clock);
	free_irq(SLAVE_IRQ, &ixp_clock);
	ixp46x_phc_index = -1;
	ptp_clock_unregister(ixp_clock.ptp_clock);
}

static int __init ptp_ixp_init(void)
{
	if (!cpu_is_ixp46x())
		return -ENODEV;

	ixp_clock.regs =
		(struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;

	ixp_clock.caps = ptp_ixp_caps;

	ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);

	if (IS_ERR(ixp_clock.ptp_clock))
		return PTR_ERR(ixp_clock.ptp_clock);

	ixp46x_phc_index = ptp_clock_index(ixp_clock.ptp_clock);

	__raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
	__raw_writel(1, &ixp_clock.regs->trgt_lo);
	__raw_writel(0, &ixp_clock.regs->trgt_hi);
	__raw_writel(TTIPEND, &ixp_clock.regs->event);

	if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
		pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
		goto no_master;
	}
	if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
		pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
		goto no_slave;
	}

	return 0;
no_slave:
	free_irq(MASTER_IRQ, &ixp_clock);
no_master:
	ptp_clock_unregister(ixp_clock.ptp_clock);
	return -ENODEV;
}

module_init(ptp_ixp_init);
module_exit(ptp_ixp_exit);

MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
MODULE_LICENSE("GPL");