xref: /linux/drivers/net/ethernet/freescale/fec_ptp.c (revision 7f71507851fc7764b36a3221839607d3a45c2025)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Fast Ethernet Controller (ENET) PTP driver for MX6x.
4  *
5  * Copyright (C) 2012 Freescale Semiconductor, Inc.
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/module.h>
11 #include <linux/kernel.h>
12 #include <linux/string.h>
13 #include <linux/ptrace.h>
14 #include <linux/errno.h>
15 #include <linux/ioport.h>
16 #include <linux/slab.h>
17 #include <linux/interrupt.h>
18 #include <linux/pci.h>
19 #include <linux/delay.h>
20 #include <linux/netdevice.h>
21 #include <linux/etherdevice.h>
22 #include <linux/skbuff.h>
23 #include <linux/spinlock.h>
24 #include <linux/workqueue.h>
25 #include <linux/bitops.h>
26 #include <linux/io.h>
27 #include <linux/irq.h>
28 #include <linux/clk.h>
29 #include <linux/platform_device.h>
30 #include <linux/phy.h>
31 #include <linux/fec.h>
32 #include <linux/of.h>
33 #include <linux/of_gpio.h>
34 #include <linux/of_net.h>
35 
36 #include "fec.h"
37 
38 /* FEC 1588 register bits */
39 #define FEC_T_CTRL_SLAVE                0x00002000
40 #define FEC_T_CTRL_CAPTURE              0x00000800
41 #define FEC_T_CTRL_RESTART              0x00000200
42 #define FEC_T_CTRL_PERIOD_RST           0x00000030
43 #define FEC_T_CTRL_PERIOD_EN		0x00000010
44 #define FEC_T_CTRL_ENABLE               0x00000001
45 
46 #define FEC_T_INC_MASK                  0x0000007f
47 #define FEC_T_INC_OFFSET                0
48 #define FEC_T_INC_CORR_MASK             0x00007f00
49 #define FEC_T_INC_CORR_OFFSET           8
50 
51 #define FEC_T_CTRL_PINPER		0x00000080
52 #define FEC_T_TF0_MASK			0x00000001
53 #define FEC_T_TF0_OFFSET		0
54 #define FEC_T_TF1_MASK			0x00000002
55 #define FEC_T_TF1_OFFSET		1
56 #define FEC_T_TF2_MASK			0x00000004
57 #define FEC_T_TF2_OFFSET		2
58 #define FEC_T_TF3_MASK			0x00000008
59 #define FEC_T_TF3_OFFSET		3
60 #define FEC_T_TDRE_MASK			0x00000001
61 #define FEC_T_TDRE_OFFSET		0
62 #define FEC_T_TMODE_MASK		0x0000003C
63 #define FEC_T_TMODE_OFFSET		2
64 #define FEC_T_TIE_MASK			0x00000040
65 #define FEC_T_TIE_OFFSET		6
66 #define FEC_T_TF_MASK			0x00000080
67 #define FEC_T_TF_OFFSET			7
68 
69 #define FEC_ATIME_CTRL		0x400
70 #define FEC_ATIME		0x404
71 #define FEC_ATIME_EVT_OFFSET	0x408
72 #define FEC_ATIME_EVT_PERIOD	0x40c
73 #define FEC_ATIME_CORR		0x410
74 #define FEC_ATIME_INC		0x414
75 #define FEC_TS_TIMESTAMP	0x418
76 
77 #define FEC_TGSR		0x604
78 #define FEC_TCSR(n)		(0x608 + n * 0x08)
79 #define FEC_TCCR(n)		(0x60C + n * 0x08)
80 #define MAX_TIMER_CHANNEL	3
81 #define FEC_TMODE_TOGGLE	0x05
82 #define FEC_HIGH_PULSE		0x0F
83 
84 #define FEC_CC_MULT	(1 << 31)
85 #define FEC_COUNTER_PERIOD	(1 << 31)
86 #define PPS_OUPUT_RELOAD_PERIOD	NSEC_PER_SEC
87 #define DEFAULT_PPS_CHANNEL	0
88 
89 #define FEC_PTP_MAX_NSEC_PERIOD		4000000000ULL
90 #define FEC_PTP_MAX_NSEC_COUNTER	0x80000000ULL
91 
92 /**
93  * fec_ptp_read - read raw cycle counter (to be used by time counter)
94  * @cc: the cyclecounter structure
95  *
96  * this function reads the cyclecounter registers and is called by the
97  * cyclecounter structure used to construct a ns counter from the
98  * arbitrary fixed point registers
99  */
100 static u64 fec_ptp_read(const struct cyclecounter *cc)
101 {
102 	struct fec_enet_private *fep =
103 		container_of(cc, struct fec_enet_private, cc);
104 	u32 tempval;
105 
106 	tempval = readl(fep->hwp + FEC_ATIME_CTRL);
107 	tempval |= FEC_T_CTRL_CAPTURE;
108 	writel(tempval, fep->hwp + FEC_ATIME_CTRL);
109 
110 	if (fep->quirks & FEC_QUIRK_BUG_CAPTURE)
111 		udelay(1);
112 
113 	return readl(fep->hwp + FEC_ATIME);
114 }
115 
116 /**
117  * fec_ptp_enable_pps
118  * @fep: the fec_enet_private structure handle
119  * @enable: enable the channel pps output
120  *
121  * This function enble the PPS ouput on the timer channel.
122  */
123 static int fec_ptp_enable_pps(struct fec_enet_private *fep, uint enable)
124 {
125 	unsigned long flags;
126 	u32 val, tempval;
127 	struct timespec64 ts;
128 	u64 ns;
129 
130 	spin_lock_irqsave(&fep->tmreg_lock, flags);
131 
132 	if (fep->pps_enable == enable) {
133 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
134 		return 0;
135 	}
136 
137 	if (enable) {
138 		/* clear capture or output compare interrupt status if have.
139 		 */
140 		writel(FEC_T_TF_MASK, fep->hwp + FEC_TCSR(fep->pps_channel));
141 
142 		/* It is recommended to double check the TMODE field in the
143 		 * TCSR register to be cleared before the first compare counter
144 		 * is written into TCCR register. Just add a double check.
145 		 */
146 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
147 		do {
148 			val &= ~(FEC_T_TMODE_MASK);
149 			writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
150 			val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
151 		} while (val & FEC_T_TMODE_MASK);
152 
153 		/* Dummy read counter to update the counter */
154 		timecounter_read(&fep->tc);
155 		/* We want to find the first compare event in the next
156 		 * second point. So we need to know what the ptp time
157 		 * is now and how many nanoseconds is ahead to get next second.
158 		 * The remaining nanosecond ahead before the next second would be
159 		 * NSEC_PER_SEC - ts.tv_nsec. Add the remaining nanoseconds
160 		 * to current timer would be next second.
161 		 */
162 		tempval = fec_ptp_read(&fep->cc);
163 		/* Convert the ptp local counter to 1588 timestamp */
164 		ns = timecounter_cyc2time(&fep->tc, tempval);
165 		ts = ns_to_timespec64(ns);
166 
167 		/* The tempval is  less than 3 seconds, and  so val is less than
168 		 * 4 seconds. No overflow for 32bit calculation.
169 		 */
170 		val = NSEC_PER_SEC - (u32)ts.tv_nsec + tempval;
171 
172 		/* Need to consider the situation that the current time is
173 		 * very close to the second point, which means NSEC_PER_SEC
174 		 * - ts.tv_nsec is close to be zero(For example 20ns); Since the timer
175 		 * is still running when we calculate the first compare event, it is
176 		 * possible that the remaining nanoseonds run out before the compare
177 		 * counter is calculated and written into TCCR register. To avoid
178 		 * this possibility, we will set the compare event to be the next
179 		 * of next second. The current setting is 31-bit timer and wrap
180 		 * around over 2 seconds. So it is okay to set the next of next
181 		 * seond for the timer.
182 		 */
183 		val += NSEC_PER_SEC;
184 
185 		/* We add (2 * NSEC_PER_SEC - (u32)ts.tv_nsec) to current
186 		 * ptp counter, which maybe cause 32-bit wrap. Since the
187 		 * (NSEC_PER_SEC - (u32)ts.tv_nsec) is less than 2 second.
188 		 * We can ensure the wrap will not cause issue. If the offset
189 		 * is bigger than fep->cc.mask would be a error.
190 		 */
191 		val &= fep->cc.mask;
192 		writel(val, fep->hwp + FEC_TCCR(fep->pps_channel));
193 
194 		/* Calculate the second the compare event timestamp */
195 		fep->next_counter = (val + fep->reload_period) & fep->cc.mask;
196 
197 		/* * Enable compare event when overflow */
198 		val = readl(fep->hwp + FEC_ATIME_CTRL);
199 		val |= FEC_T_CTRL_PINPER;
200 		writel(val, fep->hwp + FEC_ATIME_CTRL);
201 
202 		/* Compare channel setting. */
203 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
204 		val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET);
205 		val &= ~(1 << FEC_T_TDRE_OFFSET);
206 		val &= ~(FEC_T_TMODE_MASK);
207 		val |= (FEC_HIGH_PULSE << FEC_T_TMODE_OFFSET);
208 		writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
209 
210 		/* Write the second compare event timestamp and calculate
211 		 * the third timestamp. Refer the TCCR register detail in the spec.
212 		 */
213 		writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel));
214 		fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
215 	} else {
216 		writel(0, fep->hwp + FEC_TCSR(fep->pps_channel));
217 	}
218 
219 	fep->pps_enable = enable;
220 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
221 
222 	return 0;
223 }
224 
225 static int fec_ptp_pps_perout(struct fec_enet_private *fep)
226 {
227 	u32 compare_val, ptp_hc, temp_val;
228 	u64 curr_time;
229 	unsigned long flags;
230 
231 	spin_lock_irqsave(&fep->tmreg_lock, flags);
232 
233 	/* Update time counter */
234 	timecounter_read(&fep->tc);
235 
236 	/* Get the current ptp hardware time counter */
237 	ptp_hc = fec_ptp_read(&fep->cc);
238 
239 	/* Convert the ptp local counter to 1588 timestamp */
240 	curr_time = timecounter_cyc2time(&fep->tc, ptp_hc);
241 
242 	/* If the pps start time less than current time add 100ms, just return.
243 	 * Because the software might not able to set the comparison time into
244 	 * the FEC_TCCR register in time and missed the start time.
245 	 */
246 	if (fep->perout_stime < curr_time + 100 * NSEC_PER_MSEC) {
247 		dev_err(&fep->pdev->dev, "Current time is too close to the start time!\n");
248 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
249 		return -1;
250 	}
251 
252 	compare_val = fep->perout_stime - curr_time + ptp_hc;
253 	compare_val &= fep->cc.mask;
254 
255 	writel(compare_val, fep->hwp + FEC_TCCR(fep->pps_channel));
256 	fep->next_counter = (compare_val + fep->reload_period) & fep->cc.mask;
257 
258 	/* Enable compare event when overflow */
259 	temp_val = readl(fep->hwp + FEC_ATIME_CTRL);
260 	temp_val |= FEC_T_CTRL_PINPER;
261 	writel(temp_val, fep->hwp + FEC_ATIME_CTRL);
262 
263 	/* Compare channel setting. */
264 	temp_val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
265 	temp_val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET);
266 	temp_val &= ~(1 << FEC_T_TDRE_OFFSET);
267 	temp_val &= ~(FEC_T_TMODE_MASK);
268 	temp_val |= (FEC_TMODE_TOGGLE << FEC_T_TMODE_OFFSET);
269 	writel(temp_val, fep->hwp + FEC_TCSR(fep->pps_channel));
270 
271 	/* Write the second compare event timestamp and calculate
272 	 * the third timestamp. Refer the TCCR register detail in the spec.
273 	 */
274 	writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel));
275 	fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
276 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
277 
278 	return 0;
279 }
280 
281 static enum hrtimer_restart fec_ptp_pps_perout_handler(struct hrtimer *timer)
282 {
283 	struct fec_enet_private *fep = container_of(timer,
284 					struct fec_enet_private, perout_timer);
285 
286 	fec_ptp_pps_perout(fep);
287 
288 	return HRTIMER_NORESTART;
289 }
290 
291 /**
292  * fec_ptp_start_cyclecounter - create the cycle counter from hw
293  * @ndev: network device
294  *
295  * this function initializes the timecounter and cyclecounter
296  * structures for use in generated a ns counter from the arbitrary
297  * fixed point cycles registers in the hardware.
298  */
299 void fec_ptp_start_cyclecounter(struct net_device *ndev)
300 {
301 	struct fec_enet_private *fep = netdev_priv(ndev);
302 	unsigned long flags;
303 	int inc;
304 
305 	inc = 1000000000 / fep->cycle_speed;
306 
307 	/* grab the ptp lock */
308 	spin_lock_irqsave(&fep->tmreg_lock, flags);
309 
310 	/* 1ns counter */
311 	writel(inc << FEC_T_INC_OFFSET, fep->hwp + FEC_ATIME_INC);
312 
313 	/* use 31-bit timer counter */
314 	writel(FEC_COUNTER_PERIOD, fep->hwp + FEC_ATIME_EVT_PERIOD);
315 
316 	writel(FEC_T_CTRL_ENABLE | FEC_T_CTRL_PERIOD_RST,
317 		fep->hwp + FEC_ATIME_CTRL);
318 
319 	memset(&fep->cc, 0, sizeof(fep->cc));
320 	fep->cc.read = fec_ptp_read;
321 	fep->cc.mask = CLOCKSOURCE_MASK(31);
322 	fep->cc.shift = 31;
323 	fep->cc.mult = FEC_CC_MULT;
324 
325 	/* reset the ns time counter */
326 	timecounter_init(&fep->tc, &fep->cc, 0);
327 
328 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
329 }
330 
331 /**
332  * fec_ptp_adjfine - adjust ptp cycle frequency
333  * @ptp: the ptp clock structure
334  * @scaled_ppm: scaled parts per million adjustment from base
335  *
336  * Adjust the frequency of the ptp cycle counter by the
337  * indicated amount from the base frequency.
338  *
339  * Scaled parts per million is ppm with a 16-bit binary fractional field.
340  *
341  * Because ENET hardware frequency adjust is complex,
342  * using software method to do that.
343  */
344 static int fec_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
345 {
346 	s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
347 	unsigned long flags;
348 	int neg_adj = 0;
349 	u32 i, tmp;
350 	u32 corr_inc, corr_period;
351 	u32 corr_ns;
352 	u64 lhs, rhs;
353 
354 	struct fec_enet_private *fep =
355 	    container_of(ptp, struct fec_enet_private, ptp_caps);
356 
357 	if (ppb == 0)
358 		return 0;
359 
360 	if (ppb < 0) {
361 		ppb = -ppb;
362 		neg_adj = 1;
363 	}
364 
365 	/* In theory, corr_inc/corr_period = ppb/NSEC_PER_SEC;
366 	 * Try to find the corr_inc  between 1 to fep->ptp_inc to
367 	 * meet adjustment requirement.
368 	 */
369 	lhs = NSEC_PER_SEC;
370 	rhs = (u64)ppb * (u64)fep->ptp_inc;
371 	for (i = 1; i <= fep->ptp_inc; i++) {
372 		if (lhs >= rhs) {
373 			corr_inc = i;
374 			corr_period = div_u64(lhs, rhs);
375 			break;
376 		}
377 		lhs += NSEC_PER_SEC;
378 	}
379 	/* Not found? Set it to high value - double speed
380 	 * correct in every clock step.
381 	 */
382 	if (i > fep->ptp_inc) {
383 		corr_inc = fep->ptp_inc;
384 		corr_period = 1;
385 	}
386 
387 	if (neg_adj)
388 		corr_ns = fep->ptp_inc - corr_inc;
389 	else
390 		corr_ns = fep->ptp_inc + corr_inc;
391 
392 	spin_lock_irqsave(&fep->tmreg_lock, flags);
393 
394 	tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
395 	tmp |= corr_ns << FEC_T_INC_CORR_OFFSET;
396 	writel(tmp, fep->hwp + FEC_ATIME_INC);
397 	corr_period = corr_period > 1 ? corr_period - 1 : corr_period;
398 	writel(corr_period, fep->hwp + FEC_ATIME_CORR);
399 	/* dummy read to update the timer. */
400 	timecounter_read(&fep->tc);
401 
402 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
403 
404 	return 0;
405 }
406 
407 /**
408  * fec_ptp_adjtime
409  * @ptp: the ptp clock structure
410  * @delta: offset to adjust the cycle counter by
411  *
412  * adjust the timer by resetting the timecounter structure.
413  */
414 static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
415 {
416 	struct fec_enet_private *fep =
417 	    container_of(ptp, struct fec_enet_private, ptp_caps);
418 	unsigned long flags;
419 
420 	spin_lock_irqsave(&fep->tmreg_lock, flags);
421 	timecounter_adjtime(&fep->tc, delta);
422 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
423 
424 	return 0;
425 }
426 
427 /**
428  * fec_ptp_gettime
429  * @ptp: the ptp clock structure
430  * @ts: timespec structure to hold the current time value
431  *
432  * read the timecounter and return the correct value on ns,
433  * after converting it into a struct timespec.
434  */
435 static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
436 {
437 	struct fec_enet_private *fep =
438 	    container_of(ptp, struct fec_enet_private, ptp_caps);
439 	u64 ns;
440 	unsigned long flags;
441 
442 	mutex_lock(&fep->ptp_clk_mutex);
443 	/* Check the ptp clock */
444 	if (!fep->ptp_clk_on) {
445 		mutex_unlock(&fep->ptp_clk_mutex);
446 		return -EINVAL;
447 	}
448 	spin_lock_irqsave(&fep->tmreg_lock, flags);
449 	ns = timecounter_read(&fep->tc);
450 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
451 	mutex_unlock(&fep->ptp_clk_mutex);
452 
453 	*ts = ns_to_timespec64(ns);
454 
455 	return 0;
456 }
457 
458 /**
459  * fec_ptp_settime
460  * @ptp: the ptp clock structure
461  * @ts: the timespec containing the new time for the cycle counter
462  *
463  * reset the timecounter to use a new base value instead of the kernel
464  * wall timer value.
465  */
466 static int fec_ptp_settime(struct ptp_clock_info *ptp,
467 			   const struct timespec64 *ts)
468 {
469 	struct fec_enet_private *fep =
470 	    container_of(ptp, struct fec_enet_private, ptp_caps);
471 
472 	u64 ns;
473 	unsigned long flags;
474 	u32 counter;
475 
476 	mutex_lock(&fep->ptp_clk_mutex);
477 	/* Check the ptp clock */
478 	if (!fep->ptp_clk_on) {
479 		mutex_unlock(&fep->ptp_clk_mutex);
480 		return -EINVAL;
481 	}
482 
483 	ns = timespec64_to_ns(ts);
484 	/* Get the timer value based on timestamp.
485 	 * Update the counter with the masked value.
486 	 */
487 	counter = ns & fep->cc.mask;
488 
489 	spin_lock_irqsave(&fep->tmreg_lock, flags);
490 	writel(counter, fep->hwp + FEC_ATIME);
491 	timecounter_init(&fep->tc, &fep->cc, ns);
492 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
493 	mutex_unlock(&fep->ptp_clk_mutex);
494 	return 0;
495 }
496 
497 static int fec_ptp_pps_disable(struct fec_enet_private *fep, uint channel)
498 {
499 	unsigned long flags;
500 
501 	spin_lock_irqsave(&fep->tmreg_lock, flags);
502 	writel(0, fep->hwp + FEC_TCSR(channel));
503 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
504 
505 	return 0;
506 }
507 
508 /**
509  * fec_ptp_enable
510  * @ptp: the ptp clock structure
511  * @rq: the requested feature to change
512  * @on: whether to enable or disable the feature
513  *
514  */
515 static int fec_ptp_enable(struct ptp_clock_info *ptp,
516 			  struct ptp_clock_request *rq, int on)
517 {
518 	struct fec_enet_private *fep =
519 	    container_of(ptp, struct fec_enet_private, ptp_caps);
520 	ktime_t timeout;
521 	struct timespec64 start_time, period;
522 	u64 curr_time, delta, period_ns;
523 	unsigned long flags;
524 	int ret = 0;
525 
526 	if (rq->type == PTP_CLK_REQ_PPS) {
527 		fep->reload_period = PPS_OUPUT_RELOAD_PERIOD;
528 
529 		ret = fec_ptp_enable_pps(fep, on);
530 
531 		return ret;
532 	} else if (rq->type == PTP_CLK_REQ_PEROUT) {
533 		/* Reject requests with unsupported flags */
534 		if (rq->perout.flags)
535 			return -EOPNOTSUPP;
536 
537 		if (rq->perout.index != fep->pps_channel)
538 			return -EOPNOTSUPP;
539 
540 		period.tv_sec = rq->perout.period.sec;
541 		period.tv_nsec = rq->perout.period.nsec;
542 		period_ns = timespec64_to_ns(&period);
543 
544 		/* FEC PTP timer only has 31 bits, so if the period exceed
545 		 * 4s is not supported.
546 		 */
547 		if (period_ns > FEC_PTP_MAX_NSEC_PERIOD) {
548 			dev_err(&fep->pdev->dev, "The period must equal to or less than 4s!\n");
549 			return -EOPNOTSUPP;
550 		}
551 
552 		fep->reload_period = div_u64(period_ns, 2);
553 		if (on && fep->reload_period) {
554 			/* Convert 1588 timestamp to ns*/
555 			start_time.tv_sec = rq->perout.start.sec;
556 			start_time.tv_nsec = rq->perout.start.nsec;
557 			fep->perout_stime = timespec64_to_ns(&start_time);
558 
559 			mutex_lock(&fep->ptp_clk_mutex);
560 			if (!fep->ptp_clk_on) {
561 				dev_err(&fep->pdev->dev, "Error: PTP clock is closed!\n");
562 				mutex_unlock(&fep->ptp_clk_mutex);
563 				return -EOPNOTSUPP;
564 			}
565 			spin_lock_irqsave(&fep->tmreg_lock, flags);
566 			/* Read current timestamp */
567 			curr_time = timecounter_read(&fep->tc);
568 			spin_unlock_irqrestore(&fep->tmreg_lock, flags);
569 			mutex_unlock(&fep->ptp_clk_mutex);
570 
571 			/* Calculate time difference */
572 			delta = fep->perout_stime - curr_time;
573 
574 			if (fep->perout_stime <= curr_time) {
575 				dev_err(&fep->pdev->dev, "Start time must larger than current time!\n");
576 				return -EINVAL;
577 			}
578 
579 			/* Because the timer counter of FEC only has 31-bits, correspondingly,
580 			 * the time comparison register FEC_TCCR also only low 31 bits can be
581 			 * set. If the start time of pps signal exceeds current time more than
582 			 * 0x80000000 ns, a software timer is used and the timer expires about
583 			 * 1 second before the start time to be able to set FEC_TCCR.
584 			 */
585 			if (delta > FEC_PTP_MAX_NSEC_COUNTER) {
586 				timeout = ns_to_ktime(delta - NSEC_PER_SEC);
587 				hrtimer_start(&fep->perout_timer, timeout, HRTIMER_MODE_REL);
588 			} else {
589 				return fec_ptp_pps_perout(fep);
590 			}
591 		} else {
592 			fec_ptp_pps_disable(fep, fep->pps_channel);
593 		}
594 
595 		return 0;
596 	} else {
597 		return -EOPNOTSUPP;
598 	}
599 }
600 
601 int fec_ptp_set(struct net_device *ndev, struct kernel_hwtstamp_config *config,
602 		struct netlink_ext_ack *extack)
603 {
604 	struct fec_enet_private *fep = netdev_priv(ndev);
605 
606 	switch (config->tx_type) {
607 	case HWTSTAMP_TX_OFF:
608 		fep->hwts_tx_en = 0;
609 		break;
610 	case HWTSTAMP_TX_ON:
611 		fep->hwts_tx_en = 1;
612 		break;
613 	default:
614 		return -ERANGE;
615 	}
616 
617 	switch (config->rx_filter) {
618 	case HWTSTAMP_FILTER_NONE:
619 		fep->hwts_rx_en = 0;
620 		break;
621 
622 	default:
623 		fep->hwts_rx_en = 1;
624 		config->rx_filter = HWTSTAMP_FILTER_ALL;
625 		break;
626 	}
627 
628 	return 0;
629 }
630 
631 void fec_ptp_get(struct net_device *ndev, struct kernel_hwtstamp_config *config)
632 {
633 	struct fec_enet_private *fep = netdev_priv(ndev);
634 
635 	config->flags = 0;
636 	config->tx_type = fep->hwts_tx_en ? HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF;
637 	config->rx_filter = (fep->hwts_rx_en ?
638 			     HWTSTAMP_FILTER_ALL : HWTSTAMP_FILTER_NONE);
639 }
640 
641 /*
642  * fec_time_keep - call timecounter_read every second to avoid timer overrun
643  *                 because ENET just support 32bit counter, will timeout in 4s
644  */
645 static void fec_time_keep(struct work_struct *work)
646 {
647 	struct delayed_work *dwork = to_delayed_work(work);
648 	struct fec_enet_private *fep = container_of(dwork, struct fec_enet_private, time_keep);
649 	unsigned long flags;
650 
651 	mutex_lock(&fep->ptp_clk_mutex);
652 	if (fep->ptp_clk_on) {
653 		spin_lock_irqsave(&fep->tmreg_lock, flags);
654 		timecounter_read(&fep->tc);
655 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
656 	}
657 	mutex_unlock(&fep->ptp_clk_mutex);
658 
659 	schedule_delayed_work(&fep->time_keep, HZ);
660 }
661 
662 /* This function checks the pps event and reloads the timer compare counter. */
663 static irqreturn_t fec_pps_interrupt(int irq, void *dev_id)
664 {
665 	struct net_device *ndev = dev_id;
666 	struct fec_enet_private *fep = netdev_priv(ndev);
667 	u32 val;
668 	u8 channel = fep->pps_channel;
669 	struct ptp_clock_event event;
670 
671 	val = readl(fep->hwp + FEC_TCSR(channel));
672 	if (val & FEC_T_TF_MASK) {
673 		/* Write the next next compare(not the next according the spec)
674 		 * value to the register
675 		 */
676 		writel(fep->next_counter, fep->hwp + FEC_TCCR(channel));
677 		do {
678 			writel(val, fep->hwp + FEC_TCSR(channel));
679 		} while (readl(fep->hwp + FEC_TCSR(channel)) & FEC_T_TF_MASK);
680 
681 		/* Update the counter; */
682 		fep->next_counter = (fep->next_counter + fep->reload_period) &
683 				fep->cc.mask;
684 
685 		event.type = PTP_CLOCK_PPS;
686 		ptp_clock_event(fep->ptp_clock, &event);
687 		return IRQ_HANDLED;
688 	}
689 
690 	return IRQ_NONE;
691 }
692 
693 /**
694  * fec_ptp_init
695  * @pdev: The FEC network adapter
696  * @irq_idx: the interrupt index
697  *
698  * This function performs the required steps for enabling ptp
699  * support. If ptp support has already been loaded it simply calls the
700  * cyclecounter init routine and exits.
701  */
702 
703 void fec_ptp_init(struct platform_device *pdev, int irq_idx)
704 {
705 	struct net_device *ndev = platform_get_drvdata(pdev);
706 	struct fec_enet_private *fep = netdev_priv(ndev);
707 	struct device_node *np = fep->pdev->dev.of_node;
708 	int irq;
709 	int ret;
710 
711 	fep->ptp_caps.owner = THIS_MODULE;
712 	strscpy(fep->ptp_caps.name, "fec ptp", sizeof(fep->ptp_caps.name));
713 
714 	fep->pps_channel = DEFAULT_PPS_CHANNEL;
715 	of_property_read_u32(np, "fsl,pps-channel", &fep->pps_channel);
716 
717 	fep->ptp_caps.max_adj = 250000000;
718 	fep->ptp_caps.n_alarm = 0;
719 	fep->ptp_caps.n_ext_ts = 0;
720 	fep->ptp_caps.n_per_out = 1;
721 	fep->ptp_caps.n_pins = 0;
722 	fep->ptp_caps.pps = 1;
723 	fep->ptp_caps.adjfine = fec_ptp_adjfine;
724 	fep->ptp_caps.adjtime = fec_ptp_adjtime;
725 	fep->ptp_caps.gettime64 = fec_ptp_gettime;
726 	fep->ptp_caps.settime64 = fec_ptp_settime;
727 	fep->ptp_caps.enable = fec_ptp_enable;
728 
729 	fep->cycle_speed = clk_get_rate(fep->clk_ptp);
730 	if (!fep->cycle_speed) {
731 		fep->cycle_speed = NSEC_PER_SEC;
732 		dev_err(&fep->pdev->dev, "clk_ptp clock rate is zero\n");
733 	}
734 	fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
735 
736 	spin_lock_init(&fep->tmreg_lock);
737 
738 	fec_ptp_start_cyclecounter(ndev);
739 
740 	INIT_DELAYED_WORK(&fep->time_keep, fec_time_keep);
741 
742 	hrtimer_init(&fep->perout_timer, CLOCK_REALTIME, HRTIMER_MODE_REL);
743 	fep->perout_timer.function = fec_ptp_pps_perout_handler;
744 
745 	irq = platform_get_irq_byname_optional(pdev, "pps");
746 	if (irq < 0)
747 		irq = platform_get_irq_optional(pdev, irq_idx);
748 	/* Failure to get an irq is not fatal,
749 	 * only the PTP_CLOCK_PPS clock events should stop
750 	 */
751 	if (irq >= 0) {
752 		ret = devm_request_irq(&pdev->dev, irq, fec_pps_interrupt,
753 				       0, pdev->name, ndev);
754 		if (ret < 0)
755 			dev_warn(&pdev->dev, "request for pps irq failed(%d)\n",
756 				 ret);
757 	}
758 
759 	fep->ptp_clock = ptp_clock_register(&fep->ptp_caps, &pdev->dev);
760 	if (IS_ERR(fep->ptp_clock)) {
761 		fep->ptp_clock = NULL;
762 		dev_err(&pdev->dev, "ptp_clock_register failed\n");
763 	}
764 
765 	schedule_delayed_work(&fep->time_keep, HZ);
766 }
767 
768 void fec_ptp_save_state(struct fec_enet_private *fep)
769 {
770 	unsigned long flags;
771 	u32 atime_inc_corr;
772 
773 	spin_lock_irqsave(&fep->tmreg_lock, flags);
774 
775 	fep->ptp_saved_state.pps_enable = fep->pps_enable;
776 
777 	fep->ptp_saved_state.ns_phc = timecounter_read(&fep->tc);
778 	fep->ptp_saved_state.ns_sys = ktime_get_ns();
779 
780 	fep->ptp_saved_state.at_corr = readl(fep->hwp + FEC_ATIME_CORR);
781 	atime_inc_corr = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_CORR_MASK;
782 	fep->ptp_saved_state.at_inc_corr = (u8)(atime_inc_corr >> FEC_T_INC_CORR_OFFSET);
783 
784 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
785 }
786 
787 /* Restore PTP functionality after a reset */
788 void fec_ptp_restore_state(struct fec_enet_private *fep)
789 {
790 	u32 atime_inc = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
791 	unsigned long flags;
792 	u32 counter;
793 	u64 ns;
794 
795 	spin_lock_irqsave(&fep->tmreg_lock, flags);
796 
797 	/* Reset turned it off, so adjust our status flag */
798 	fep->pps_enable = 0;
799 
800 	writel(fep->ptp_saved_state.at_corr, fep->hwp + FEC_ATIME_CORR);
801 	atime_inc |= ((u32)fep->ptp_saved_state.at_inc_corr) << FEC_T_INC_CORR_OFFSET;
802 	writel(atime_inc, fep->hwp + FEC_ATIME_INC);
803 
804 	ns = ktime_get_ns() - fep->ptp_saved_state.ns_sys + fep->ptp_saved_state.ns_phc;
805 	counter = ns & fep->cc.mask;
806 	writel(counter, fep->hwp + FEC_ATIME);
807 	timecounter_init(&fep->tc, &fep->cc, ns);
808 
809 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
810 
811 	/* Restart PPS if needed */
812 	if (fep->ptp_saved_state.pps_enable) {
813 		/* Re-enable PPS */
814 		fec_ptp_enable_pps(fep, 1);
815 	}
816 }
817 
818 void fec_ptp_stop(struct platform_device *pdev)
819 {
820 	struct net_device *ndev = platform_get_drvdata(pdev);
821 	struct fec_enet_private *fep = netdev_priv(ndev);
822 
823 	if (fep->pps_enable)
824 		fec_ptp_enable_pps(fep, 0);
825 
826 	cancel_delayed_work_sync(&fep->time_keep);
827 	hrtimer_cancel(&fep->perout_timer);
828 	if (fep->ptp_clock)
829 		ptp_clock_unregister(fep->ptp_clock);
830 }
831