1/*
2 * PTP 1588 clock using the IXP46X
3 *
4 * Copyright (C) 2010 OMICRON electronics GmbH
5 *
6 *  This program is free software; you can redistribute it and/or modify
7 *  it under the terms of the GNU General Public License as published by
8 *  the Free Software Foundation; either version 2 of the License, or
9 *  (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20#include <linux/device.h>
21#include <linux/err.h>
22#include <linux/gpio.h>
23#include <linux/init.h>
24#include <linux/interrupt.h>
25#include <linux/io.h>
26#include <linux/irq.h>
27#include <linux/kernel.h>
28#include <linux/module.h>
29
30#include <linux/ptp_clock_kernel.h>
31#include <mach/ixp46x_ts.h>
32
33#define DRIVER		"ptp_ixp46x"
34#define N_EXT_TS	2
35#define MASTER_GPIO	8
36#define MASTER_IRQ	25
37#define SLAVE_GPIO	7
38#define SLAVE_IRQ	24
39
40struct ixp_clock {
41	struct ixp46x_ts_regs *regs;
42	struct ptp_clock *ptp_clock;
43	struct ptp_clock_info caps;
44	int exts0_enabled;
45	int exts1_enabled;
46};
47
48DEFINE_SPINLOCK(register_lock);
49
50/*
51 * Register access functions
52 */
53
54static u64 ixp_systime_read(struct ixp46x_ts_regs *regs)
55{
56	u64 ns;
57	u32 lo, hi;
58
59	lo = __raw_readl(&regs->systime_lo);
60	hi = __raw_readl(&regs->systime_hi);
61
62	ns = ((u64) hi) << 32;
63	ns |= lo;
64	ns <<= TICKS_NS_SHIFT;
65
66	return ns;
67}
68
69static void ixp_systime_write(struct ixp46x_ts_regs *regs, u64 ns)
70{
71	u32 hi, lo;
72
73	ns >>= TICKS_NS_SHIFT;
74	hi = ns >> 32;
75	lo = ns & 0xffffffff;
76
77	__raw_writel(lo, &regs->systime_lo);
78	__raw_writel(hi, &regs->systime_hi);
79}
80
81/*
82 * Interrupt service routine
83 */
84
85static irqreturn_t isr(int irq, void *priv)
86{
87	struct ixp_clock *ixp_clock = priv;
88	struct ixp46x_ts_regs *regs = ixp_clock->regs;
89	struct ptp_clock_event event;
90	u32 ack = 0, lo, hi, val;
91
92	val = __raw_readl(&regs->event);
93
94	if (val & TSER_SNS) {
95		ack |= TSER_SNS;
96		if (ixp_clock->exts0_enabled) {
97			hi = __raw_readl(&regs->asms_hi);
98			lo = __raw_readl(&regs->asms_lo);
99			event.type = PTP_CLOCK_EXTTS;
100			event.index = 0;
101			event.timestamp = ((u64) hi) << 32;
102			event.timestamp |= lo;
103			event.timestamp <<= TICKS_NS_SHIFT;
104			ptp_clock_event(ixp_clock->ptp_clock, &event);
105		}
106	}
107
108	if (val & TSER_SNM) {
109		ack |= TSER_SNM;
110		if (ixp_clock->exts1_enabled) {
111			hi = __raw_readl(&regs->amms_hi);
112			lo = __raw_readl(&regs->amms_lo);
113			event.type = PTP_CLOCK_EXTTS;
114			event.index = 1;
115			event.timestamp = ((u64) hi) << 32;
116			event.timestamp |= lo;
117			event.timestamp <<= TICKS_NS_SHIFT;
118			ptp_clock_event(ixp_clock->ptp_clock, &event);
119		}
120	}
121
122	if (val & TTIPEND)
123		ack |= TTIPEND; /* this bit seems to be always set */
124
125	if (ack) {
126		__raw_writel(ack, &regs->event);
127		return IRQ_HANDLED;
128	} else
129		return IRQ_NONE;
130}
131
132/*
133 * PTP clock operations
134 */
135
136static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
137{
138	u64 adj;
139	u32 diff, addend;
140	int neg_adj = 0;
141	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
142	struct ixp46x_ts_regs *regs = ixp_clock->regs;
143
144	if (ppb < 0) {
145		neg_adj = 1;
146		ppb = -ppb;
147	}
148	addend = DEFAULT_ADDEND;
149	adj = addend;
150	adj *= ppb;
151	diff = div_u64(adj, 1000000000ULL);
152
153	addend = neg_adj ? addend - diff : addend + diff;
154
155	__raw_writel(addend, &regs->addend);
156
157	return 0;
158}
159
160static int ptp_ixp_adjtime(struct ptp_clock_info *ptp, s64 delta)
161{
162	s64 now;
163	unsigned long flags;
164	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
165	struct ixp46x_ts_regs *regs = ixp_clock->regs;
166
167	spin_lock_irqsave(&register_lock, flags);
168
169	now = ixp_systime_read(regs);
170	now += delta;
171	ixp_systime_write(regs, now);
172
173	spin_unlock_irqrestore(&register_lock, flags);
174
175	return 0;
176}
177
178static int ptp_ixp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
179{
180	u64 ns;
181	u32 remainder;
182	unsigned long flags;
183	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
184	struct ixp46x_ts_regs *regs = ixp_clock->regs;
185
186	spin_lock_irqsave(&register_lock, flags);
187
188	ns = ixp_systime_read(regs);
189
190	spin_unlock_irqrestore(&register_lock, flags);
191
192	ts->tv_sec = div_u64_rem(ns, 1000000000, &remainder);
193	ts->tv_nsec = remainder;
194	return 0;
195}
196
197static int ptp_ixp_settime(struct ptp_clock_info *ptp,
198			   const struct timespec64 *ts)
199{
200	u64 ns;
201	unsigned long flags;
202	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
203	struct ixp46x_ts_regs *regs = ixp_clock->regs;
204
205	ns = ts->tv_sec * 1000000000ULL;
206	ns += ts->tv_nsec;
207
208	spin_lock_irqsave(&register_lock, flags);
209
210	ixp_systime_write(regs, ns);
211
212	spin_unlock_irqrestore(&register_lock, flags);
213
214	return 0;
215}
216
217static int ptp_ixp_enable(struct ptp_clock_info *ptp,
218			  struct ptp_clock_request *rq, int on)
219{
220	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
221
222	switch (rq->type) {
223	case PTP_CLK_REQ_EXTTS:
224		switch (rq->extts.index) {
225		case 0:
226			ixp_clock->exts0_enabled = on ? 1 : 0;
227			break;
228		case 1:
229			ixp_clock->exts1_enabled = on ? 1 : 0;
230			break;
231		default:
232			return -EINVAL;
233		}
234		return 0;
235	default:
236		break;
237	}
238
239	return -EOPNOTSUPP;
240}
241
242static struct ptp_clock_info ptp_ixp_caps = {
243	.owner		= THIS_MODULE,
244	.name		= "IXP46X timer",
245	.max_adj	= 66666655,
246	.n_ext_ts	= N_EXT_TS,
247	.n_pins		= 0,
248	.pps		= 0,
249	.adjfreq	= ptp_ixp_adjfreq,
250	.adjtime	= ptp_ixp_adjtime,
251	.gettime64	= ptp_ixp_gettime,
252	.settime64	= ptp_ixp_settime,
253	.enable		= ptp_ixp_enable,
254};
255
256/* module operations */
257
258static struct ixp_clock ixp_clock;
259
260static int setup_interrupt(int gpio)
261{
262	int irq;
263	int err;
264
265	err = gpio_request(gpio, "ixp4-ptp");
266	if (err)
267		return err;
268
269	err = gpio_direction_input(gpio);
270	if (err)
271		return err;
272
273	irq = gpio_to_irq(gpio);
274
275	if (NO_IRQ == irq)
276		return NO_IRQ;
277
278	if (irq_set_irq_type(irq, IRQF_TRIGGER_FALLING)) {
279		pr_err("cannot set trigger type for irq %d\n", irq);
280		return NO_IRQ;
281	}
282
283	if (request_irq(irq, isr, 0, DRIVER, &ixp_clock)) {
284		pr_err("request_irq failed for irq %d\n", irq);
285		return NO_IRQ;
286	}
287
288	return irq;
289}
290
291static void __exit ptp_ixp_exit(void)
292{
293	free_irq(MASTER_IRQ, &ixp_clock);
294	free_irq(SLAVE_IRQ, &ixp_clock);
295	ixp46x_phc_index = -1;
296	ptp_clock_unregister(ixp_clock.ptp_clock);
297}
298
299static int __init ptp_ixp_init(void)
300{
301	if (!cpu_is_ixp46x())
302		return -ENODEV;
303
304	ixp_clock.regs =
305		(struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
306
307	ixp_clock.caps = ptp_ixp_caps;
308
309	ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps, NULL);
310
311	if (IS_ERR(ixp_clock.ptp_clock))
312		return PTR_ERR(ixp_clock.ptp_clock);
313
314	ixp46x_phc_index = ptp_clock_index(ixp_clock.ptp_clock);
315
316	__raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
317	__raw_writel(1, &ixp_clock.regs->trgt_lo);
318	__raw_writel(0, &ixp_clock.regs->trgt_hi);
319	__raw_writel(TTIPEND, &ixp_clock.regs->event);
320
321	if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
322		pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
323		goto no_master;
324	}
325	if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
326		pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
327		goto no_slave;
328	}
329
330	return 0;
331no_slave:
332	free_irq(MASTER_IRQ, &ixp_clock);
333no_master:
334	ptp_clock_unregister(ixp_clock.ptp_clock);
335	return -ENODEV;
336}
337
338module_init(ptp_ixp_init);
339module_exit(ptp_ixp_exit);
340
341MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");
342MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
343MODULE_LICENSE("GPL");
344