1/* PTP 1588 clock using the Renesas Ethernet AVB
  2 *
  3 * Copyright (C) 2013-2015 Renesas Electronics Corporation
  4 * Copyright (C) 2015 Renesas Solutions Corp.
  5 * Copyright (C) 2015-2016 Cogent Embedded, Inc. <source@cogentembedded.com>
  6 *
  7 *  This program is free software; you can redistribute it and/or modify
  8 *  it under the terms of the GNU General Public License as published by
  9 *  the Free Software Foundation; either version 2 of the License, or
 10 *  (at your option) any later version.
 11 */
 12
 13#include "ravb.h"
 14
 15static int ravb_ptp_tcr_request(struct ravb_private *priv, u32 request)
 16{
 17	struct net_device *ndev = priv->ndev;
 18	int error;
 19
 20	error = ravb_wait(ndev, GCCR, GCCR_TCR, GCCR_TCR_NOREQ);
 21	if (error)
 22		return error;
 23
 24	ravb_modify(ndev, GCCR, request, request);
 25	return ravb_wait(ndev, GCCR, GCCR_TCR, GCCR_TCR_NOREQ);
 26}
 27
 28/* Caller must hold the lock */
 29static int ravb_ptp_time_read(struct ravb_private *priv, struct timespec64 *ts)
 30{
 31	struct net_device *ndev = priv->ndev;
 32	int error;
 33
 34	error = ravb_ptp_tcr_request(priv, GCCR_TCR_CAPTURE);
 35	if (error)
 36		return error;
 37
 38	ts->tv_nsec = ravb_read(ndev, GCT0);
 39	ts->tv_sec  = ravb_read(ndev, GCT1) |
 40		((s64)ravb_read(ndev, GCT2) << 32);
 41
 42	return 0;
 43}
 44
 45/* Caller must hold the lock */
 46static int ravb_ptp_time_write(struct ravb_private *priv,
 47				const struct timespec64 *ts)
 48{
 49	struct net_device *ndev = priv->ndev;
 50	int error;
 51	u32 gccr;
 52
 53	error = ravb_ptp_tcr_request(priv, GCCR_TCR_RESET);
 54	if (error)
 55		return error;
 56
 57	gccr = ravb_read(ndev, GCCR);
 58	if (gccr & GCCR_LTO)
 59		return -EBUSY;
 60	ravb_write(ndev, ts->tv_nsec, GTO0);
 61	ravb_write(ndev, ts->tv_sec,  GTO1);
 62	ravb_write(ndev, (ts->tv_sec >> 32) & 0xffff, GTO2);
 63	ravb_write(ndev, gccr | GCCR_LTO, GCCR);
 64
 65	return 0;
 66}
 67
 68/* Caller must hold the lock */
 69static int ravb_ptp_update_compare(struct ravb_private *priv, u32 ns)
 70{
 71	struct net_device *ndev = priv->ndev;
 72	/* When the comparison value (GPTC.PTCV) is in range of
 73	 * [x-1 to x+1] (x is the configured increment value in
 74	 * GTI.TIV), it may happen that a comparison match is
 75	 * not detected when the timer wraps around.
 76	 */
 77	u32 gti_ns_plus_1 = (priv->ptp.current_addend >> 20) + 1;
 78	u32 gccr;
 79
 80	if (ns < gti_ns_plus_1)
 81		ns = gti_ns_plus_1;
 82	else if (ns > 0 - gti_ns_plus_1)
 83		ns = 0 - gti_ns_plus_1;
 84
 85	gccr = ravb_read(ndev, GCCR);
 86	if (gccr & GCCR_LPTC)
 87		return -EBUSY;
 88	ravb_write(ndev, ns, GPTC);
 89	ravb_write(ndev, gccr | GCCR_LPTC, GCCR);
 90
 91	return 0;
 92}
 93
 94/* PTP clock operations */
 95static int ravb_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 96{
 97	struct ravb_private *priv = container_of(ptp, struct ravb_private,
 98						 ptp.info);
 99	struct net_device *ndev = priv->ndev;
100	unsigned long flags;
101	u32 diff, addend;
102	bool neg_adj = false;
103	u32 gccr;
104
105	if (ppb < 0) {
106		neg_adj = true;
107		ppb = -ppb;
108	}
109	addend = priv->ptp.default_addend;
110	diff = div_u64((u64)addend * ppb, NSEC_PER_SEC);
111
112	addend = neg_adj ? addend - diff : addend + diff;
113
114	spin_lock_irqsave(&priv->lock, flags);
115
116	priv->ptp.current_addend = addend;
117
118	gccr = ravb_read(ndev, GCCR);
119	if (gccr & GCCR_LTI) {
120		spin_unlock_irqrestore(&priv->lock, flags);
121		return -EBUSY;
122	}
123	ravb_write(ndev, addend & GTI_TIV, GTI);
124	ravb_write(ndev, gccr | GCCR_LTI, GCCR);
125
126	spin_unlock_irqrestore(&priv->lock, flags);
127
128	return 0;
129}
130
131static int ravb_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
132{
133	struct ravb_private *priv = container_of(ptp, struct ravb_private,
134						 ptp.info);
135	struct timespec64 ts;
136	unsigned long flags;
137	int error;
138
139	spin_lock_irqsave(&priv->lock, flags);
140	error = ravb_ptp_time_read(priv, &ts);
141	if (!error) {
142		u64 now = ktime_to_ns(timespec64_to_ktime(ts));
143
144		ts = ns_to_timespec64(now + delta);
145		error = ravb_ptp_time_write(priv, &ts);
146	}
147	spin_unlock_irqrestore(&priv->lock, flags);
148
149	return error;
150}
151
152static int ravb_ptp_gettime64(struct ptp_clock_info *ptp, struct timespec64 *ts)
153{
154	struct ravb_private *priv = container_of(ptp, struct ravb_private,
155						 ptp.info);
156	unsigned long flags;
157	int error;
158
159	spin_lock_irqsave(&priv->lock, flags);
160	error = ravb_ptp_time_read(priv, ts);
161	spin_unlock_irqrestore(&priv->lock, flags);
162
163	return error;
164}
165
166static int ravb_ptp_settime64(struct ptp_clock_info *ptp,
167			      const struct timespec64 *ts)
168{
169	struct ravb_private *priv = container_of(ptp, struct ravb_private,
170						 ptp.info);
171	unsigned long flags;
172	int error;
173
174	spin_lock_irqsave(&priv->lock, flags);
175	error = ravb_ptp_time_write(priv, ts);
176	spin_unlock_irqrestore(&priv->lock, flags);
177
178	return error;
179}
180
181static int ravb_ptp_extts(struct ptp_clock_info *ptp,
182			  struct ptp_extts_request *req, int on)
183{
184	struct ravb_private *priv = container_of(ptp, struct ravb_private,
185						 ptp.info);
186	struct net_device *ndev = priv->ndev;
187	unsigned long flags;
188
189	if (req->index)
190		return -EINVAL;
191
192	if (priv->ptp.extts[req->index] == on)
193		return 0;
194	priv->ptp.extts[req->index] = on;
195
196	spin_lock_irqsave(&priv->lock, flags);
197	ravb_modify(ndev, GIC, GIC_PTCE, on ? GIC_PTCE : 0);
198	mmiowb();
199	spin_unlock_irqrestore(&priv->lock, flags);
200
201	return 0;
202}
203
204static int ravb_ptp_perout(struct ptp_clock_info *ptp,
205			   struct ptp_perout_request *req, int on)
206{
207	struct ravb_private *priv = container_of(ptp, struct ravb_private,
208						 ptp.info);
209	struct net_device *ndev = priv->ndev;
210	struct ravb_ptp_perout *perout;
211	unsigned long flags;
212	int error = 0;
213
214	if (req->index)
215		return -EINVAL;
216
217	if (on) {
218		u64 start_ns;
219		u64 period_ns;
220
221		start_ns = req->start.sec * NSEC_PER_SEC + req->start.nsec;
222		period_ns = req->period.sec * NSEC_PER_SEC + req->period.nsec;
223
224		if (start_ns > U32_MAX) {
225			netdev_warn(ndev,
226				    "ptp: start value (nsec) is over limit. Maximum size of start is only 32 bits\n");
227			return -ERANGE;
228		}
229
230		if (period_ns > U32_MAX) {
231			netdev_warn(ndev,
232				    "ptp: period value (nsec) is over limit. Maximum size of period is only 32 bits\n");
233			return -ERANGE;
234		}
235
236		spin_lock_irqsave(&priv->lock, flags);
237
238		perout = &priv->ptp.perout[req->index];
239		perout->target = (u32)start_ns;
240		perout->period = (u32)period_ns;
241		error = ravb_ptp_update_compare(priv, (u32)start_ns);
242		if (!error) {
243			/* Unmask interrupt */
244			ravb_modify(ndev, GIC, GIC_PTME, GIC_PTME);
245		}
246	} else	{
247		spin_lock_irqsave(&priv->lock, flags);
248
249		perout = &priv->ptp.perout[req->index];
250		perout->period = 0;
251
252		/* Mask interrupt */
253		ravb_modify(ndev, GIC, GIC_PTME, 0);
254	}
255	mmiowb();
256	spin_unlock_irqrestore(&priv->lock, flags);
257
258	return error;
259}
260
261static int ravb_ptp_enable(struct ptp_clock_info *ptp,
262			   struct ptp_clock_request *req, int on)
263{
264	switch (req->type) {
265	case PTP_CLK_REQ_EXTTS:
266		return ravb_ptp_extts(ptp, &req->extts, on);
267	case PTP_CLK_REQ_PEROUT:
268		return ravb_ptp_perout(ptp, &req->perout, on);
269	default:
270		return -EOPNOTSUPP;
271	}
272}
273
274static const struct ptp_clock_info ravb_ptp_info = {
275	.owner		= THIS_MODULE,
276	.name		= "ravb clock",
277	.max_adj	= 50000000,
278	.n_ext_ts	= N_EXT_TS,
279	.n_per_out	= N_PER_OUT,
280	.adjfreq	= ravb_ptp_adjfreq,
281	.adjtime	= ravb_ptp_adjtime,
282	.gettime64	= ravb_ptp_gettime64,
283	.settime64	= ravb_ptp_settime64,
284	.enable		= ravb_ptp_enable,
285};
286
287/* Caller must hold the lock */
288irqreturn_t ravb_ptp_interrupt(struct net_device *ndev)
289{
290	struct ravb_private *priv = netdev_priv(ndev);
291	u32 gis = ravb_read(ndev, GIS);
292
293	gis &= ravb_read(ndev, GIC);
294	if (gis & GIS_PTCF) {
295		struct ptp_clock_event event;
296
297		event.type = PTP_CLOCK_EXTTS;
298		event.index = 0;
299		event.timestamp = ravb_read(ndev, GCPT);
300		ptp_clock_event(priv->ptp.clock, &event);
301	}
302	if (gis & GIS_PTMF) {
303		struct ravb_ptp_perout *perout = priv->ptp.perout;
304
305		if (perout->period) {
306			perout->target += perout->period;
307			ravb_ptp_update_compare(priv, perout->target);
308		}
309	}
310
311	if (gis) {
312		ravb_write(ndev, ~gis, GIS);
313		return IRQ_HANDLED;
314	}
315
316	return IRQ_NONE;
317}
318
319void ravb_ptp_init(struct net_device *ndev, struct platform_device *pdev)
320{
321	struct ravb_private *priv = netdev_priv(ndev);
322	unsigned long flags;
323
324	priv->ptp.info = ravb_ptp_info;
325
326	priv->ptp.default_addend = ravb_read(ndev, GTI);
327	priv->ptp.current_addend = priv->ptp.default_addend;
328
329	spin_lock_irqsave(&priv->lock, flags);
330	ravb_wait(ndev, GCCR, GCCR_TCR, GCCR_TCR_NOREQ);
331	ravb_modify(ndev, GCCR, GCCR_TCSS, GCCR_TCSS_ADJGPTP);
332	mmiowb();
333	spin_unlock_irqrestore(&priv->lock, flags);
334
335	priv->ptp.clock = ptp_clock_register(&priv->ptp.info, &pdev->dev);
336}
337
338void ravb_ptp_stop(struct net_device *ndev)
339{
340	struct ravb_private *priv = netdev_priv(ndev);
341
342	ravb_write(ndev, 0, GIC);
343	ravb_write(ndev, 0, GIS);
344
345	ptp_clock_unregister(priv->ptp.clock);
346}