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 timespec *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 timespec *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	.pps		= 0,
248	.adjfreq	= ptp_ixp_adjfreq,
249	.adjtime	= ptp_ixp_adjtime,
250	.gettime	= ptp_ixp_gettime,
251	.settime	= ptp_ixp_settime,
252	.enable		= ptp_ixp_enable,
253};
254
255/* module operations */
256
257static struct ixp_clock ixp_clock;
258
259static int setup_interrupt(int gpio)
260{
261	int irq;
262
263	gpio_line_config(gpio, IXP4XX_GPIO_IN);
264
265	irq = gpio_to_irq(gpio);
266
267	if (NO_IRQ == irq)
268		return NO_IRQ;
269
270	if (irq_set_irq_type(irq, IRQF_TRIGGER_FALLING)) {
271		pr_err("cannot set trigger type for irq %d\n", irq);
272		return NO_IRQ;
273	}
274
275	if (request_irq(irq, isr, 0, DRIVER, &ixp_clock)) {
276		pr_err("request_irq failed for irq %d\n", irq);
277		return NO_IRQ;
278	}
279
280	return irq;
281}
282
283static void __exit ptp_ixp_exit(void)
284{
285	free_irq(MASTER_IRQ, &ixp_clock);
286	free_irq(SLAVE_IRQ, &ixp_clock);
287	ptp_clock_unregister(ixp_clock.ptp_clock);
288}
289
290static int __init ptp_ixp_init(void)
291{
292	if (!cpu_is_ixp46x())
293		return -ENODEV;
294
295	ixp_clock.regs =
296		(struct ixp46x_ts_regs __iomem *) IXP4XX_TIMESYNC_BASE_VIRT;
297
298	ixp_clock.caps = ptp_ixp_caps;
299
300	ixp_clock.ptp_clock = ptp_clock_register(&ixp_clock.caps);
301
302	if (IS_ERR(ixp_clock.ptp_clock))
303		return PTR_ERR(ixp_clock.ptp_clock);
304
305	__raw_writel(DEFAULT_ADDEND, &ixp_clock.regs->addend);
306	__raw_writel(1, &ixp_clock.regs->trgt_lo);
307	__raw_writel(0, &ixp_clock.regs->trgt_hi);
308	__raw_writel(TTIPEND, &ixp_clock.regs->event);
309
310	if (MASTER_IRQ != setup_interrupt(MASTER_GPIO)) {
311		pr_err("failed to setup gpio %d as irq\n", MASTER_GPIO);
312		goto no_master;
313	}
314	if (SLAVE_IRQ != setup_interrupt(SLAVE_GPIO)) {
315		pr_err("failed to setup gpio %d as irq\n", SLAVE_GPIO);
316		goto no_slave;
317	}
318
319	return 0;
320no_slave:
321	free_irq(MASTER_IRQ, &ixp_clock);
322no_master:
323	ptp_clock_unregister(ixp_clock.ptp_clock);
324	return -ENODEV;
325}
326
327module_init(ptp_ixp_init);
328module_exit(ptp_ixp_exit);
329
330MODULE_AUTHOR("Richard Cochran <richard.cochran@omicron.at>");
331MODULE_DESCRIPTION("PTP clock using the IXP46X timer");
332MODULE_LICENSE("GPL");