xref: /linux/drivers/net/ethernet/freescale/fec_ptp.c (revision 2fe3c78a2c26dd5ee811024a1b7d6cfb4d654319)
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 FEC_CHANNLE_0		0
88 #define DEFAULT_PPS_CHANNEL	FEC_CHANNLE_0
89 
90 #define FEC_PTP_MAX_NSEC_PERIOD		4000000000ULL
91 #define FEC_PTP_MAX_NSEC_COUNTER	0x80000000ULL
92 
93 /**
94  * fec_ptp_read - read raw cycle counter (to be used by time counter)
95  * @cc: the cyclecounter structure
96  *
97  * this function reads the cyclecounter registers and is called by the
98  * cyclecounter structure used to construct a ns counter from the
99  * arbitrary fixed point registers
100  */
101 static u64 fec_ptp_read(const struct cyclecounter *cc)
102 {
103 	struct fec_enet_private *fep =
104 		container_of(cc, struct fec_enet_private, cc);
105 	u32 tempval;
106 
107 	tempval = readl(fep->hwp + FEC_ATIME_CTRL);
108 	tempval |= FEC_T_CTRL_CAPTURE;
109 	writel(tempval, fep->hwp + FEC_ATIME_CTRL);
110 
111 	if (fep->quirks & FEC_QUIRK_BUG_CAPTURE)
112 		udelay(1);
113 
114 	return readl(fep->hwp + FEC_ATIME);
115 }
116 
117 /**
118  * fec_ptp_enable_pps
119  * @fep: the fec_enet_private structure handle
120  * @enable: enable the channel pps output
121  *
122  * This function enble the PPS ouput on the timer channel.
123  */
124 static int fec_ptp_enable_pps(struct fec_enet_private *fep, uint enable)
125 {
126 	unsigned long flags;
127 	u32 val, tempval;
128 	struct timespec64 ts;
129 	u64 ns;
130 
131 	spin_lock_irqsave(&fep->tmreg_lock, flags);
132 
133 	if (fep->pps_enable == enable) {
134 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
135 		return 0;
136 	}
137 
138 	if (enable) {
139 		/* clear capture or output compare interrupt status if have.
140 		 */
141 		writel(FEC_T_TF_MASK, fep->hwp + FEC_TCSR(fep->pps_channel));
142 
143 		/* It is recommended to double check the TMODE field in the
144 		 * TCSR register to be cleared before the first compare counter
145 		 * is written into TCCR register. Just add a double check.
146 		 */
147 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
148 		do {
149 			val &= ~(FEC_T_TMODE_MASK);
150 			writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
151 			val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
152 		} while (val & FEC_T_TMODE_MASK);
153 
154 		/* Dummy read counter to update the counter */
155 		timecounter_read(&fep->tc);
156 		/* We want to find the first compare event in the next
157 		 * second point. So we need to know what the ptp time
158 		 * is now and how many nanoseconds is ahead to get next second.
159 		 * The remaining nanosecond ahead before the next second would be
160 		 * NSEC_PER_SEC - ts.tv_nsec. Add the remaining nanoseconds
161 		 * to current timer would be next second.
162 		 */
163 		tempval = fec_ptp_read(&fep->cc);
164 		/* Convert the ptp local counter to 1588 timestamp */
165 		ns = timecounter_cyc2time(&fep->tc, tempval);
166 		ts = ns_to_timespec64(ns);
167 
168 		/* The tempval is  less than 3 seconds, and  so val is less than
169 		 * 4 seconds. No overflow for 32bit calculation.
170 		 */
171 		val = NSEC_PER_SEC - (u32)ts.tv_nsec + tempval;
172 
173 		/* Need to consider the situation that the current time is
174 		 * very close to the second point, which means NSEC_PER_SEC
175 		 * - ts.tv_nsec is close to be zero(For example 20ns); Since the timer
176 		 * is still running when we calculate the first compare event, it is
177 		 * possible that the remaining nanoseonds run out before the compare
178 		 * counter is calculated and written into TCCR register. To avoid
179 		 * this possibility, we will set the compare event to be the next
180 		 * of next second. The current setting is 31-bit timer and wrap
181 		 * around over 2 seconds. So it is okay to set the next of next
182 		 * seond for the timer.
183 		 */
184 		val += NSEC_PER_SEC;
185 
186 		/* We add (2 * NSEC_PER_SEC - (u32)ts.tv_nsec) to current
187 		 * ptp counter, which maybe cause 32-bit wrap. Since the
188 		 * (NSEC_PER_SEC - (u32)ts.tv_nsec) is less than 2 second.
189 		 * We can ensure the wrap will not cause issue. If the offset
190 		 * is bigger than fep->cc.mask would be a error.
191 		 */
192 		val &= fep->cc.mask;
193 		writel(val, fep->hwp + FEC_TCCR(fep->pps_channel));
194 
195 		/* Calculate the second the compare event timestamp */
196 		fep->next_counter = (val + fep->reload_period) & fep->cc.mask;
197 
198 		/* * Enable compare event when overflow */
199 		val = readl(fep->hwp + FEC_ATIME_CTRL);
200 		val |= FEC_T_CTRL_PINPER;
201 		writel(val, fep->hwp + FEC_ATIME_CTRL);
202 
203 		/* Compare channel setting. */
204 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
205 		val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET);
206 		val &= ~(1 << FEC_T_TDRE_OFFSET);
207 		val &= ~(FEC_T_TMODE_MASK);
208 		val |= (FEC_HIGH_PULSE << FEC_T_TMODE_OFFSET);
209 		writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
210 
211 		/* Write the second compare event timestamp and calculate
212 		 * the third timestamp. Refer the TCCR register detail in the spec.
213 		 */
214 		writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel));
215 		fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
216 	} else {
217 		writel(0, fep->hwp + FEC_TCSR(fep->pps_channel));
218 	}
219 
220 	fep->pps_enable = enable;
221 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
222 
223 	return 0;
224 }
225 
226 static int fec_ptp_pps_perout(struct fec_enet_private *fep)
227 {
228 	u32 compare_val, ptp_hc, temp_val;
229 	u64 curr_time;
230 	unsigned long flags;
231 
232 	spin_lock_irqsave(&fep->tmreg_lock, flags);
233 
234 	/* Update time counter */
235 	timecounter_read(&fep->tc);
236 
237 	/* Get the current ptp hardware time counter */
238 	ptp_hc = fec_ptp_read(&fep->cc);
239 
240 	/* Convert the ptp local counter to 1588 timestamp */
241 	curr_time = timecounter_cyc2time(&fep->tc, ptp_hc);
242 
243 	/* If the pps start time less than current time add 100ms, just return.
244 	 * Because the software might not able to set the comparison time into
245 	 * the FEC_TCCR register in time and missed the start time.
246 	 */
247 	if (fep->perout_stime < curr_time + 100 * NSEC_PER_MSEC) {
248 		dev_err(&fep->pdev->dev, "Current time is too close to the start time!\n");
249 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
250 		return -1;
251 	}
252 
253 	compare_val = fep->perout_stime - curr_time + ptp_hc;
254 	compare_val &= fep->cc.mask;
255 
256 	writel(compare_val, fep->hwp + FEC_TCCR(fep->pps_channel));
257 	fep->next_counter = (compare_val + fep->reload_period) & fep->cc.mask;
258 
259 	/* Enable compare event when overflow */
260 	temp_val = readl(fep->hwp + FEC_ATIME_CTRL);
261 	temp_val |= FEC_T_CTRL_PINPER;
262 	writel(temp_val, fep->hwp + FEC_ATIME_CTRL);
263 
264 	/* Compare channel setting. */
265 	temp_val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
266 	temp_val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET);
267 	temp_val &= ~(1 << FEC_T_TDRE_OFFSET);
268 	temp_val &= ~(FEC_T_TMODE_MASK);
269 	temp_val |= (FEC_TMODE_TOGGLE << FEC_T_TMODE_OFFSET);
270 	writel(temp_val, fep->hwp + FEC_TCSR(fep->pps_channel));
271 
272 	/* Write the second compare event timestamp and calculate
273 	 * the third timestamp. Refer the TCCR register detail in the spec.
274 	 */
275 	writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel));
276 	fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
277 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
278 
279 	return 0;
280 }
281 
282 static enum hrtimer_restart fec_ptp_pps_perout_handler(struct hrtimer *timer)
283 {
284 	struct fec_enet_private *fep = container_of(timer,
285 					struct fec_enet_private, perout_timer);
286 
287 	fec_ptp_pps_perout(fep);
288 
289 	return HRTIMER_NORESTART;
290 }
291 
292 /**
293  * fec_ptp_start_cyclecounter - create the cycle counter from hw
294  * @ndev: network device
295  *
296  * this function initializes the timecounter and cyclecounter
297  * structures for use in generated a ns counter from the arbitrary
298  * fixed point cycles registers in the hardware.
299  */
300 void fec_ptp_start_cyclecounter(struct net_device *ndev)
301 {
302 	struct fec_enet_private *fep = netdev_priv(ndev);
303 	unsigned long flags;
304 	int inc;
305 
306 	inc = 1000000000 / fep->cycle_speed;
307 
308 	/* grab the ptp lock */
309 	spin_lock_irqsave(&fep->tmreg_lock, flags);
310 
311 	/* 1ns counter */
312 	writel(inc << FEC_T_INC_OFFSET, fep->hwp + FEC_ATIME_INC);
313 
314 	/* use 31-bit timer counter */
315 	writel(FEC_COUNTER_PERIOD, fep->hwp + FEC_ATIME_EVT_PERIOD);
316 
317 	writel(FEC_T_CTRL_ENABLE | FEC_T_CTRL_PERIOD_RST,
318 		fep->hwp + FEC_ATIME_CTRL);
319 
320 	memset(&fep->cc, 0, sizeof(fep->cc));
321 	fep->cc.read = fec_ptp_read;
322 	fep->cc.mask = CLOCKSOURCE_MASK(31);
323 	fep->cc.shift = 31;
324 	fep->cc.mult = FEC_CC_MULT;
325 
326 	/* reset the ns time counter */
327 	timecounter_init(&fep->tc, &fep->cc, 0);
328 
329 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
330 }
331 
332 /**
333  * fec_ptp_adjfine - adjust ptp cycle frequency
334  * @ptp: the ptp clock structure
335  * @scaled_ppm: scaled parts per million adjustment from base
336  *
337  * Adjust the frequency of the ptp cycle counter by the
338  * indicated amount from the base frequency.
339  *
340  * Scaled parts per million is ppm with a 16-bit binary fractional field.
341  *
342  * Because ENET hardware frequency adjust is complex,
343  * using software method to do that.
344  */
345 static int fec_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
346 {
347 	s32 ppb = scaled_ppm_to_ppb(scaled_ppm);
348 	unsigned long flags;
349 	int neg_adj = 0;
350 	u32 i, tmp;
351 	u32 corr_inc, corr_period;
352 	u32 corr_ns;
353 	u64 lhs, rhs;
354 
355 	struct fec_enet_private *fep =
356 	    container_of(ptp, struct fec_enet_private, ptp_caps);
357 
358 	if (ppb == 0)
359 		return 0;
360 
361 	if (ppb < 0) {
362 		ppb = -ppb;
363 		neg_adj = 1;
364 	}
365 
366 	/* In theory, corr_inc/corr_period = ppb/NSEC_PER_SEC;
367 	 * Try to find the corr_inc  between 1 to fep->ptp_inc to
368 	 * meet adjustment requirement.
369 	 */
370 	lhs = NSEC_PER_SEC;
371 	rhs = (u64)ppb * (u64)fep->ptp_inc;
372 	for (i = 1; i <= fep->ptp_inc; i++) {
373 		if (lhs >= rhs) {
374 			corr_inc = i;
375 			corr_period = div_u64(lhs, rhs);
376 			break;
377 		}
378 		lhs += NSEC_PER_SEC;
379 	}
380 	/* Not found? Set it to high value - double speed
381 	 * correct in every clock step.
382 	 */
383 	if (i > fep->ptp_inc) {
384 		corr_inc = fep->ptp_inc;
385 		corr_period = 1;
386 	}
387 
388 	if (neg_adj)
389 		corr_ns = fep->ptp_inc - corr_inc;
390 	else
391 		corr_ns = fep->ptp_inc + corr_inc;
392 
393 	spin_lock_irqsave(&fep->tmreg_lock, flags);
394 
395 	tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
396 	tmp |= corr_ns << FEC_T_INC_CORR_OFFSET;
397 	writel(tmp, fep->hwp + FEC_ATIME_INC);
398 	corr_period = corr_period > 1 ? corr_period - 1 : corr_period;
399 	writel(corr_period, fep->hwp + FEC_ATIME_CORR);
400 	/* dummy read to update the timer. */
401 	timecounter_read(&fep->tc);
402 
403 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
404 
405 	return 0;
406 }
407 
408 /**
409  * fec_ptp_adjtime
410  * @ptp: the ptp clock structure
411  * @delta: offset to adjust the cycle counter by
412  *
413  * adjust the timer by resetting the timecounter structure.
414  */
415 static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
416 {
417 	struct fec_enet_private *fep =
418 	    container_of(ptp, struct fec_enet_private, ptp_caps);
419 	unsigned long flags;
420 
421 	spin_lock_irqsave(&fep->tmreg_lock, flags);
422 	timecounter_adjtime(&fep->tc, delta);
423 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
424 
425 	return 0;
426 }
427 
428 /**
429  * fec_ptp_gettime
430  * @ptp: the ptp clock structure
431  * @ts: timespec structure to hold the current time value
432  *
433  * read the timecounter and return the correct value on ns,
434  * after converting it into a struct timespec.
435  */
436 static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
437 {
438 	struct fec_enet_private *fep =
439 	    container_of(ptp, struct fec_enet_private, ptp_caps);
440 	u64 ns;
441 	unsigned long flags;
442 
443 	mutex_lock(&fep->ptp_clk_mutex);
444 	/* Check the ptp clock */
445 	if (!fep->ptp_clk_on) {
446 		mutex_unlock(&fep->ptp_clk_mutex);
447 		return -EINVAL;
448 	}
449 	spin_lock_irqsave(&fep->tmreg_lock, flags);
450 	ns = timecounter_read(&fep->tc);
451 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
452 	mutex_unlock(&fep->ptp_clk_mutex);
453 
454 	*ts = ns_to_timespec64(ns);
455 
456 	return 0;
457 }
458 
459 /**
460  * fec_ptp_settime
461  * @ptp: the ptp clock structure
462  * @ts: the timespec containing the new time for the cycle counter
463  *
464  * reset the timecounter to use a new base value instead of the kernel
465  * wall timer value.
466  */
467 static int fec_ptp_settime(struct ptp_clock_info *ptp,
468 			   const struct timespec64 *ts)
469 {
470 	struct fec_enet_private *fep =
471 	    container_of(ptp, struct fec_enet_private, ptp_caps);
472 
473 	u64 ns;
474 	unsigned long flags;
475 	u32 counter;
476 
477 	mutex_lock(&fep->ptp_clk_mutex);
478 	/* Check the ptp clock */
479 	if (!fep->ptp_clk_on) {
480 		mutex_unlock(&fep->ptp_clk_mutex);
481 		return -EINVAL;
482 	}
483 
484 	ns = timespec64_to_ns(ts);
485 	/* Get the timer value based on timestamp.
486 	 * Update the counter with the masked value.
487 	 */
488 	counter = ns & fep->cc.mask;
489 
490 	spin_lock_irqsave(&fep->tmreg_lock, flags);
491 	writel(counter, fep->hwp + FEC_ATIME);
492 	timecounter_init(&fep->tc, &fep->cc, ns);
493 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
494 	mutex_unlock(&fep->ptp_clk_mutex);
495 	return 0;
496 }
497 
498 static int fec_ptp_pps_disable(struct fec_enet_private *fep, uint channel)
499 {
500 	unsigned long flags;
501 
502 	spin_lock_irqsave(&fep->tmreg_lock, flags);
503 	writel(0, fep->hwp + FEC_TCSR(channel));
504 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
505 
506 	return 0;
507 }
508 
509 /**
510  * fec_ptp_enable
511  * @ptp: the ptp clock structure
512  * @rq: the requested feature to change
513  * @on: whether to enable or disable the feature
514  *
515  */
516 static int fec_ptp_enable(struct ptp_clock_info *ptp,
517 			  struct ptp_clock_request *rq, int on)
518 {
519 	struct fec_enet_private *fep =
520 	    container_of(ptp, struct fec_enet_private, ptp_caps);
521 	ktime_t timeout;
522 	struct timespec64 start_time, period;
523 	u64 curr_time, delta, period_ns;
524 	unsigned long flags;
525 	int ret = 0;
526 
527 	if (rq->type == PTP_CLK_REQ_PPS) {
528 		fep->pps_channel = DEFAULT_PPS_CHANNEL;
529 		fep->reload_period = PPS_OUPUT_RELOAD_PERIOD;
530 
531 		ret = fec_ptp_enable_pps(fep, on);
532 
533 		return ret;
534 	} else if (rq->type == PTP_CLK_REQ_PEROUT) {
535 		/* Reject requests with unsupported flags */
536 		if (rq->perout.flags)
537 			return -EOPNOTSUPP;
538 
539 		if (rq->perout.index != DEFAULT_PPS_CHANNEL)
540 			return -EOPNOTSUPP;
541 
542 		fep->pps_channel = DEFAULT_PPS_CHANNEL;
543 		period.tv_sec = rq->perout.period.sec;
544 		period.tv_nsec = rq->perout.period.nsec;
545 		period_ns = timespec64_to_ns(&period);
546 
547 		/* FEC PTP timer only has 31 bits, so if the period exceed
548 		 * 4s is not supported.
549 		 */
550 		if (period_ns > FEC_PTP_MAX_NSEC_PERIOD) {
551 			dev_err(&fep->pdev->dev, "The period must equal to or less than 4s!\n");
552 			return -EOPNOTSUPP;
553 		}
554 
555 		fep->reload_period = div_u64(period_ns, 2);
556 		if (on && fep->reload_period) {
557 			/* Convert 1588 timestamp to ns*/
558 			start_time.tv_sec = rq->perout.start.sec;
559 			start_time.tv_nsec = rq->perout.start.nsec;
560 			fep->perout_stime = timespec64_to_ns(&start_time);
561 
562 			mutex_lock(&fep->ptp_clk_mutex);
563 			if (!fep->ptp_clk_on) {
564 				dev_err(&fep->pdev->dev, "Error: PTP clock is closed!\n");
565 				mutex_unlock(&fep->ptp_clk_mutex);
566 				return -EOPNOTSUPP;
567 			}
568 			spin_lock_irqsave(&fep->tmreg_lock, flags);
569 			/* Read current timestamp */
570 			curr_time = timecounter_read(&fep->tc);
571 			spin_unlock_irqrestore(&fep->tmreg_lock, flags);
572 			mutex_unlock(&fep->ptp_clk_mutex);
573 
574 			/* Calculate time difference */
575 			delta = fep->perout_stime - curr_time;
576 
577 			if (fep->perout_stime <= curr_time) {
578 				dev_err(&fep->pdev->dev, "Start time must larger than current time!\n");
579 				return -EINVAL;
580 			}
581 
582 			/* Because the timer counter of FEC only has 31-bits, correspondingly,
583 			 * the time comparison register FEC_TCCR also only low 31 bits can be
584 			 * set. If the start time of pps signal exceeds current time more than
585 			 * 0x80000000 ns, a software timer is used and the timer expires about
586 			 * 1 second before the start time to be able to set FEC_TCCR.
587 			 */
588 			if (delta > FEC_PTP_MAX_NSEC_COUNTER) {
589 				timeout = ns_to_ktime(delta - NSEC_PER_SEC);
590 				hrtimer_start(&fep->perout_timer, timeout, HRTIMER_MODE_REL);
591 			} else {
592 				return fec_ptp_pps_perout(fep);
593 			}
594 		} else {
595 			fec_ptp_pps_disable(fep, fep->pps_channel);
596 		}
597 
598 		return 0;
599 	} else {
600 		return -EOPNOTSUPP;
601 	}
602 }
603 
604 int fec_ptp_set(struct net_device *ndev, struct kernel_hwtstamp_config *config,
605 		struct netlink_ext_ack *extack)
606 {
607 	struct fec_enet_private *fep = netdev_priv(ndev);
608 
609 	switch (config->tx_type) {
610 	case HWTSTAMP_TX_OFF:
611 		fep->hwts_tx_en = 0;
612 		break;
613 	case HWTSTAMP_TX_ON:
614 		fep->hwts_tx_en = 1;
615 		break;
616 	default:
617 		return -ERANGE;
618 	}
619 
620 	switch (config->rx_filter) {
621 	case HWTSTAMP_FILTER_NONE:
622 		fep->hwts_rx_en = 0;
623 		break;
624 
625 	default:
626 		fep->hwts_rx_en = 1;
627 		config->rx_filter = HWTSTAMP_FILTER_ALL;
628 		break;
629 	}
630 
631 	return 0;
632 }
633 
634 void fec_ptp_get(struct net_device *ndev, struct kernel_hwtstamp_config *config)
635 {
636 	struct fec_enet_private *fep = netdev_priv(ndev);
637 
638 	config->flags = 0;
639 	config->tx_type = fep->hwts_tx_en ? HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF;
640 	config->rx_filter = (fep->hwts_rx_en ?
641 			     HWTSTAMP_FILTER_ALL : HWTSTAMP_FILTER_NONE);
642 }
643 
644 /*
645  * fec_time_keep - call timecounter_read every second to avoid timer overrun
646  *                 because ENET just support 32bit counter, will timeout in 4s
647  */
648 static void fec_time_keep(struct work_struct *work)
649 {
650 	struct delayed_work *dwork = to_delayed_work(work);
651 	struct fec_enet_private *fep = container_of(dwork, struct fec_enet_private, time_keep);
652 	unsigned long flags;
653 
654 	mutex_lock(&fep->ptp_clk_mutex);
655 	if (fep->ptp_clk_on) {
656 		spin_lock_irqsave(&fep->tmreg_lock, flags);
657 		timecounter_read(&fep->tc);
658 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
659 	}
660 	mutex_unlock(&fep->ptp_clk_mutex);
661 
662 	schedule_delayed_work(&fep->time_keep, HZ);
663 }
664 
665 /* This function checks the pps event and reloads the timer compare counter. */
666 static irqreturn_t fec_pps_interrupt(int irq, void *dev_id)
667 {
668 	struct net_device *ndev = dev_id;
669 	struct fec_enet_private *fep = netdev_priv(ndev);
670 	u32 val;
671 	u8 channel = fep->pps_channel;
672 	struct ptp_clock_event event;
673 
674 	val = readl(fep->hwp + FEC_TCSR(channel));
675 	if (val & FEC_T_TF_MASK) {
676 		/* Write the next next compare(not the next according the spec)
677 		 * value to the register
678 		 */
679 		writel(fep->next_counter, fep->hwp + FEC_TCCR(channel));
680 		do {
681 			writel(val, fep->hwp + FEC_TCSR(channel));
682 		} while (readl(fep->hwp + FEC_TCSR(channel)) & FEC_T_TF_MASK);
683 
684 		/* Update the counter; */
685 		fep->next_counter = (fep->next_counter + fep->reload_period) &
686 				fep->cc.mask;
687 
688 		event.type = PTP_CLOCK_PPS;
689 		ptp_clock_event(fep->ptp_clock, &event);
690 		return IRQ_HANDLED;
691 	}
692 
693 	return IRQ_NONE;
694 }
695 
696 /**
697  * fec_ptp_init
698  * @pdev: The FEC network adapter
699  * @irq_idx: the interrupt index
700  *
701  * This function performs the required steps for enabling ptp
702  * support. If ptp support has already been loaded it simply calls the
703  * cyclecounter init routine and exits.
704  */
705 
706 void fec_ptp_init(struct platform_device *pdev, int irq_idx)
707 {
708 	struct net_device *ndev = platform_get_drvdata(pdev);
709 	struct fec_enet_private *fep = netdev_priv(ndev);
710 	int irq;
711 	int ret;
712 
713 	fep->ptp_caps.owner = THIS_MODULE;
714 	strscpy(fep->ptp_caps.name, "fec ptp", sizeof(fep->ptp_caps.name));
715 
716 	fep->ptp_caps.max_adj = 250000000;
717 	fep->ptp_caps.n_alarm = 0;
718 	fep->ptp_caps.n_ext_ts = 0;
719 	fep->ptp_caps.n_per_out = 1;
720 	fep->ptp_caps.n_pins = 0;
721 	fep->ptp_caps.pps = 1;
722 	fep->ptp_caps.adjfine = fec_ptp_adjfine;
723 	fep->ptp_caps.adjtime = fec_ptp_adjtime;
724 	fep->ptp_caps.gettime64 = fec_ptp_gettime;
725 	fep->ptp_caps.settime64 = fec_ptp_settime;
726 	fep->ptp_caps.enable = fec_ptp_enable;
727 
728 	fep->cycle_speed = clk_get_rate(fep->clk_ptp);
729 	if (!fep->cycle_speed) {
730 		fep->cycle_speed = NSEC_PER_SEC;
731 		dev_err(&fep->pdev->dev, "clk_ptp clock rate is zero\n");
732 	}
733 	fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
734 
735 	spin_lock_init(&fep->tmreg_lock);
736 
737 	fec_ptp_start_cyclecounter(ndev);
738 
739 	INIT_DELAYED_WORK(&fep->time_keep, fec_time_keep);
740 
741 	hrtimer_init(&fep->perout_timer, CLOCK_REALTIME, HRTIMER_MODE_REL);
742 	fep->perout_timer.function = fec_ptp_pps_perout_handler;
743 
744 	irq = platform_get_irq_byname_optional(pdev, "pps");
745 	if (irq < 0)
746 		irq = platform_get_irq_optional(pdev, irq_idx);
747 	/* Failure to get an irq is not fatal,
748 	 * only the PTP_CLOCK_PPS clock events should stop
749 	 */
750 	if (irq >= 0) {
751 		ret = devm_request_irq(&pdev->dev, irq, fec_pps_interrupt,
752 				       0, pdev->name, ndev);
753 		if (ret < 0)
754 			dev_warn(&pdev->dev, "request for pps irq failed(%d)\n",
755 				 ret);
756 	}
757 
758 	fep->ptp_clock = ptp_clock_register(&fep->ptp_caps, &pdev->dev);
759 	if (IS_ERR(fep->ptp_clock)) {
760 		fep->ptp_clock = NULL;
761 		dev_err(&pdev->dev, "ptp_clock_register failed\n");
762 	}
763 
764 	schedule_delayed_work(&fep->time_keep, HZ);
765 }
766 
767 void fec_ptp_stop(struct platform_device *pdev)
768 {
769 	struct net_device *ndev = platform_get_drvdata(pdev);
770 	struct fec_enet_private *fep = netdev_priv(ndev);
771 
772 	if (fep->pps_enable)
773 		fec_ptp_enable_pps(fep, 0);
774 
775 	cancel_delayed_work_sync(&fep->time_keep);
776 	hrtimer_cancel(&fep->perout_timer);
777 	if (fep->ptp_clock)
778 		ptp_clock_unregister(fep->ptp_clock);
779 }
780