1 /*
2  * Fast Ethernet Controller (ENET) PTP driver for MX6x.
3  *
4  * Copyright (C) 2012 Freescale Semiconductor, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program; if not, write to the Free Software Foundation, Inc.,
17  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
18  */
19 
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
21 
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/string.h>
25 #include <linux/ptrace.h>
26 #include <linux/errno.h>
27 #include <linux/ioport.h>
28 #include <linux/slab.h>
29 #include <linux/interrupt.h>
30 #include <linux/pci.h>
31 #include <linux/delay.h>
32 #include <linux/netdevice.h>
33 #include <linux/etherdevice.h>
34 #include <linux/skbuff.h>
35 #include <linux/spinlock.h>
36 #include <linux/workqueue.h>
37 #include <linux/bitops.h>
38 #include <linux/io.h>
39 #include <linux/irq.h>
40 #include <linux/clk.h>
41 #include <linux/platform_device.h>
42 #include <linux/phy.h>
43 #include <linux/fec.h>
44 #include <linux/of.h>
45 #include <linux/of_device.h>
46 #include <linux/of_gpio.h>
47 #include <linux/of_net.h>
48 
49 #include "fec.h"
50 
51 /* FEC 1588 register bits */
52 #define FEC_T_CTRL_SLAVE                0x00002000
53 #define FEC_T_CTRL_CAPTURE              0x00000800
54 #define FEC_T_CTRL_RESTART              0x00000200
55 #define FEC_T_CTRL_PERIOD_RST           0x00000030
56 #define FEC_T_CTRL_PERIOD_EN		0x00000010
57 #define FEC_T_CTRL_ENABLE               0x00000001
58 
59 #define FEC_T_INC_MASK                  0x0000007f
60 #define FEC_T_INC_OFFSET                0
61 #define FEC_T_INC_CORR_MASK             0x00007f00
62 #define FEC_T_INC_CORR_OFFSET           8
63 
64 #define FEC_T_CTRL_PINPER		0x00000080
65 #define FEC_T_TF0_MASK			0x00000001
66 #define FEC_T_TF0_OFFSET		0
67 #define FEC_T_TF1_MASK			0x00000002
68 #define FEC_T_TF1_OFFSET		1
69 #define FEC_T_TF2_MASK			0x00000004
70 #define FEC_T_TF2_OFFSET		2
71 #define FEC_T_TF3_MASK			0x00000008
72 #define FEC_T_TF3_OFFSET		3
73 #define FEC_T_TDRE_MASK			0x00000001
74 #define FEC_T_TDRE_OFFSET		0
75 #define FEC_T_TMODE_MASK		0x0000003C
76 #define FEC_T_TMODE_OFFSET		2
77 #define FEC_T_TIE_MASK			0x00000040
78 #define FEC_T_TIE_OFFSET		6
79 #define FEC_T_TF_MASK			0x00000080
80 #define FEC_T_TF_OFFSET			7
81 
82 #define FEC_ATIME_CTRL		0x400
83 #define FEC_ATIME		0x404
84 #define FEC_ATIME_EVT_OFFSET	0x408
85 #define FEC_ATIME_EVT_PERIOD	0x40c
86 #define FEC_ATIME_CORR		0x410
87 #define FEC_ATIME_INC		0x414
88 #define FEC_TS_TIMESTAMP	0x418
89 
90 #define FEC_TGSR		0x604
91 #define FEC_TCSR(n)		(0x608 + n * 0x08)
92 #define FEC_TCCR(n)		(0x60C + n * 0x08)
93 #define MAX_TIMER_CHANNEL	3
94 #define FEC_TMODE_TOGGLE	0x05
95 #define FEC_HIGH_PULSE		0x0F
96 
97 #define FEC_CC_MULT	(1 << 31)
98 #define FEC_COUNTER_PERIOD	(1 << 31)
99 #define PPS_OUPUT_RELOAD_PERIOD	NSEC_PER_SEC
100 #define FEC_CHANNLE_0		0
101 #define DEFAULT_PPS_CHANNEL	FEC_CHANNLE_0
102 
103 /**
104  * fec_ptp_enable_pps
105  * @fep: the fec_enet_private structure handle
106  * @enable: enable the channel pps output
107  *
108  * This function enble the PPS ouput on the timer channel.
109  */
110 static int fec_ptp_enable_pps(struct fec_enet_private *fep, uint enable)
111 {
112 	unsigned long flags;
113 	u32 val, tempval;
114 	int inc;
115 	struct timespec ts;
116 	u64 ns;
117 	u32 remainder;
118 	val = 0;
119 
120 	if (!(fep->hwts_tx_en || fep->hwts_rx_en)) {
121 		dev_err(&fep->pdev->dev, "No ptp stack is running\n");
122 		return -EINVAL;
123 	}
124 
125 	if (fep->pps_enable == enable)
126 		return 0;
127 
128 	fep->pps_channel = DEFAULT_PPS_CHANNEL;
129 	fep->reload_period = PPS_OUPUT_RELOAD_PERIOD;
130 	inc = fep->ptp_inc;
131 
132 	spin_lock_irqsave(&fep->tmreg_lock, flags);
133 
134 	if (enable) {
135 		/* clear capture or output compare interrupt status if have.
136 		 */
137 		writel(FEC_T_TF_MASK, fep->hwp + FEC_TCSR(fep->pps_channel));
138 
139 		/* It is recommended to double check the TMODE field in the
140 		 * TCSR register to be cleared before the first compare counter
141 		 * is written into TCCR register. Just add a double check.
142 		 */
143 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
144 		do {
145 			val &= ~(FEC_T_TMODE_MASK);
146 			writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
147 			val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
148 		} while (val & FEC_T_TMODE_MASK);
149 
150 		/* Dummy read counter to update the counter */
151 		timecounter_read(&fep->tc);
152 		/* We want to find the first compare event in the next
153 		 * second point. So we need to know what the ptp time
154 		 * is now and how many nanoseconds is ahead to get next second.
155 		 * The remaining nanosecond ahead before the next second would be
156 		 * NSEC_PER_SEC - ts.tv_nsec. Add the remaining nanoseconds
157 		 * to current timer would be next second.
158 		 */
159 		tempval = readl(fep->hwp + FEC_ATIME_CTRL);
160 		tempval |= FEC_T_CTRL_CAPTURE;
161 		writel(tempval, fep->hwp + FEC_ATIME_CTRL);
162 
163 		tempval = readl(fep->hwp + FEC_ATIME);
164 		/* Convert the ptp local counter to 1588 timestamp */
165 		ns = timecounter_cyc2time(&fep->tc, tempval);
166 		ts.tv_sec = div_u64_rem(ns, 1000000000ULL, &remainder);
167 		ts.tv_nsec = remainder;
168 
169 		/* The tempval is  less than 3 seconds, and  so val is less than
170 		 * 4 seconds. No overflow for 32bit calculation.
171 		 */
172 		val = NSEC_PER_SEC - (u32)ts.tv_nsec + tempval;
173 
174 		/* Need to consider the situation that the current time is
175 		 * very close to the second point, which means NSEC_PER_SEC
176 		 * - ts.tv_nsec is close to be zero(For example 20ns); Since the timer
177 		 * is still running when we calculate the first compare event, it is
178 		 * possible that the remaining nanoseonds run out before the compare
179 		 * counter is calculated and written into TCCR register. To avoid
180 		 * this possibility, we will set the compare event to be the next
181 		 * of next second. The current setting is 31-bit timer and wrap
182 		 * around over 2 seconds. So it is okay to set the next of next
183 		 * seond for the timer.
184 		 */
185 		val += NSEC_PER_SEC;
186 
187 		/* We add (2 * NSEC_PER_SEC - (u32)ts.tv_nsec) to current
188 		 * ptp counter, which maybe cause 32-bit wrap. Since the
189 		 * (NSEC_PER_SEC - (u32)ts.tv_nsec) is less than 2 second.
190 		 * We can ensure the wrap will not cause issue. If the offset
191 		 * is bigger than fep->cc.mask would be a error.
192 		 */
193 		val &= fep->cc.mask;
194 		writel(val, fep->hwp + FEC_TCCR(fep->pps_channel));
195 
196 		/* Calculate the second the compare event timestamp */
197 		fep->next_counter = (val + fep->reload_period) & fep->cc.mask;
198 
199 		/* * Enable compare event when overflow */
200 		val = readl(fep->hwp + FEC_ATIME_CTRL);
201 		val |= FEC_T_CTRL_PINPER;
202 		writel(val, fep->hwp + FEC_ATIME_CTRL);
203 
204 		/* Compare channel setting. */
205 		val = readl(fep->hwp + FEC_TCSR(fep->pps_channel));
206 		val |= (1 << FEC_T_TF_OFFSET | 1 << FEC_T_TIE_OFFSET);
207 		val &= ~(1 << FEC_T_TDRE_OFFSET);
208 		val &= ~(FEC_T_TMODE_MASK);
209 		val |= (FEC_HIGH_PULSE << FEC_T_TMODE_OFFSET);
210 		writel(val, fep->hwp + FEC_TCSR(fep->pps_channel));
211 
212 		/* Write the second compare event timestamp and calculate
213 		 * the third timestamp. Refer the TCCR register detail in the spec.
214 		 */
215 		writel(fep->next_counter, fep->hwp + FEC_TCCR(fep->pps_channel));
216 		fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
217 	} else {
218 		writel(0, fep->hwp + FEC_TCSR(fep->pps_channel));
219 	}
220 
221 	fep->pps_enable = enable;
222 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
223 
224 	return 0;
225 }
226 
227 /**
228  * fec_ptp_read - read raw cycle counter (to be used by time counter)
229  * @cc: the cyclecounter structure
230  *
231  * this function reads the cyclecounter registers and is called by the
232  * cyclecounter structure used to construct a ns counter from the
233  * arbitrary fixed point registers
234  */
235 static cycle_t fec_ptp_read(const struct cyclecounter *cc)
236 {
237 	struct fec_enet_private *fep =
238 		container_of(cc, struct fec_enet_private, cc);
239 	const struct platform_device_id *id_entry =
240 		platform_get_device_id(fep->pdev);
241 	u32 tempval;
242 
243 	tempval = readl(fep->hwp + FEC_ATIME_CTRL);
244 	tempval |= FEC_T_CTRL_CAPTURE;
245 	writel(tempval, fep->hwp + FEC_ATIME_CTRL);
246 
247 	if (id_entry->driver_data & FEC_QUIRK_BUG_CAPTURE)
248 		udelay(1);
249 
250 	return readl(fep->hwp + FEC_ATIME);
251 }
252 
253 /**
254  * fec_ptp_start_cyclecounter - create the cycle counter from hw
255  * @ndev: network device
256  *
257  * this function initializes the timecounter and cyclecounter
258  * structures for use in generated a ns counter from the arbitrary
259  * fixed point cycles registers in the hardware.
260  */
261 void fec_ptp_start_cyclecounter(struct net_device *ndev)
262 {
263 	struct fec_enet_private *fep = netdev_priv(ndev);
264 	unsigned long flags;
265 	int inc;
266 
267 	inc = 1000000000 / fep->cycle_speed;
268 
269 	/* grab the ptp lock */
270 	spin_lock_irqsave(&fep->tmreg_lock, flags);
271 
272 	/* 1ns counter */
273 	writel(inc << FEC_T_INC_OFFSET, fep->hwp + FEC_ATIME_INC);
274 
275 	/* use 31-bit timer counter */
276 	writel(FEC_COUNTER_PERIOD, fep->hwp + FEC_ATIME_EVT_PERIOD);
277 
278 	writel(FEC_T_CTRL_ENABLE | FEC_T_CTRL_PERIOD_RST,
279 		fep->hwp + FEC_ATIME_CTRL);
280 
281 	memset(&fep->cc, 0, sizeof(fep->cc));
282 	fep->cc.read = fec_ptp_read;
283 	fep->cc.mask = CLOCKSOURCE_MASK(31);
284 	fep->cc.shift = 31;
285 	fep->cc.mult = FEC_CC_MULT;
286 
287 	/* reset the ns time counter */
288 	timecounter_init(&fep->tc, &fep->cc, ktime_to_ns(ktime_get_real()));
289 
290 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
291 }
292 
293 /**
294  * fec_ptp_adjfreq - adjust ptp cycle frequency
295  * @ptp: the ptp clock structure
296  * @ppb: parts per billion adjustment from base
297  *
298  * Adjust the frequency of the ptp cycle counter by the
299  * indicated ppb from the base frequency.
300  *
301  * Because ENET hardware frequency adjust is complex,
302  * using software method to do that.
303  */
304 static int fec_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
305 {
306 	unsigned long flags;
307 	int neg_adj = 0;
308 	u32 i, tmp;
309 	u32 corr_inc, corr_period;
310 	u32 corr_ns;
311 	u64 lhs, rhs;
312 
313 	struct fec_enet_private *fep =
314 	    container_of(ptp, struct fec_enet_private, ptp_caps);
315 
316 	if (ppb == 0)
317 		return 0;
318 
319 	if (ppb < 0) {
320 		ppb = -ppb;
321 		neg_adj = 1;
322 	}
323 
324 	/* In theory, corr_inc/corr_period = ppb/NSEC_PER_SEC;
325 	 * Try to find the corr_inc  between 1 to fep->ptp_inc to
326 	 * meet adjustment requirement.
327 	 */
328 	lhs = NSEC_PER_SEC;
329 	rhs = (u64)ppb * (u64)fep->ptp_inc;
330 	for (i = 1; i <= fep->ptp_inc; i++) {
331 		if (lhs >= rhs) {
332 			corr_inc = i;
333 			corr_period = div_u64(lhs, rhs);
334 			break;
335 		}
336 		lhs += NSEC_PER_SEC;
337 	}
338 	/* Not found? Set it to high value - double speed
339 	 * correct in every clock step.
340 	 */
341 	if (i > fep->ptp_inc) {
342 		corr_inc = fep->ptp_inc;
343 		corr_period = 1;
344 	}
345 
346 	if (neg_adj)
347 		corr_ns = fep->ptp_inc - corr_inc;
348 	else
349 		corr_ns = fep->ptp_inc + corr_inc;
350 
351 	spin_lock_irqsave(&fep->tmreg_lock, flags);
352 
353 	tmp = readl(fep->hwp + FEC_ATIME_INC) & FEC_T_INC_MASK;
354 	tmp |= corr_ns << FEC_T_INC_CORR_OFFSET;
355 	writel(tmp, fep->hwp + FEC_ATIME_INC);
356 	writel(corr_period, fep->hwp + FEC_ATIME_CORR);
357 	/* dummy read to update the timer. */
358 	timecounter_read(&fep->tc);
359 
360 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
361 
362 	return 0;
363 }
364 
365 /**
366  * fec_ptp_adjtime
367  * @ptp: the ptp clock structure
368  * @delta: offset to adjust the cycle counter by
369  *
370  * adjust the timer by resetting the timecounter structure.
371  */
372 static int fec_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
373 {
374 	struct fec_enet_private *fep =
375 	    container_of(ptp, struct fec_enet_private, ptp_caps);
376 	unsigned long flags;
377 
378 	spin_lock_irqsave(&fep->tmreg_lock, flags);
379 	timecounter_adjtime(&fep->tc, delta);
380 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
381 
382 	return 0;
383 }
384 
385 /**
386  * fec_ptp_gettime
387  * @ptp: the ptp clock structure
388  * @ts: timespec structure to hold the current time value
389  *
390  * read the timecounter and return the correct value on ns,
391  * after converting it into a struct timespec.
392  */
393 static int fec_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
394 {
395 	struct fec_enet_private *adapter =
396 	    container_of(ptp, struct fec_enet_private, ptp_caps);
397 	u64 ns;
398 	unsigned long flags;
399 
400 	spin_lock_irqsave(&adapter->tmreg_lock, flags);
401 	ns = timecounter_read(&adapter->tc);
402 	spin_unlock_irqrestore(&adapter->tmreg_lock, flags);
403 
404 	*ts = ns_to_timespec64(ns);
405 
406 	return 0;
407 }
408 
409 /**
410  * fec_ptp_settime
411  * @ptp: the ptp clock structure
412  * @ts: the timespec containing the new time for the cycle counter
413  *
414  * reset the timecounter to use a new base value instead of the kernel
415  * wall timer value.
416  */
417 static int fec_ptp_settime(struct ptp_clock_info *ptp,
418 			   const struct timespec64 *ts)
419 {
420 	struct fec_enet_private *fep =
421 	    container_of(ptp, struct fec_enet_private, ptp_caps);
422 
423 	u64 ns;
424 	unsigned long flags;
425 	u32 counter;
426 
427 	mutex_lock(&fep->ptp_clk_mutex);
428 	/* Check the ptp clock */
429 	if (!fep->ptp_clk_on) {
430 		mutex_unlock(&fep->ptp_clk_mutex);
431 		return -EINVAL;
432 	}
433 
434 	ns = timespec64_to_ns(ts);
435 	/* Get the timer value based on timestamp.
436 	 * Update the counter with the masked value.
437 	 */
438 	counter = ns & fep->cc.mask;
439 
440 	spin_lock_irqsave(&fep->tmreg_lock, flags);
441 	writel(counter, fep->hwp + FEC_ATIME);
442 	timecounter_init(&fep->tc, &fep->cc, ns);
443 	spin_unlock_irqrestore(&fep->tmreg_lock, flags);
444 	mutex_unlock(&fep->ptp_clk_mutex);
445 	return 0;
446 }
447 
448 /**
449  * fec_ptp_enable
450  * @ptp: the ptp clock structure
451  * @rq: the requested feature to change
452  * @on: whether to enable or disable the feature
453  *
454  */
455 static int fec_ptp_enable(struct ptp_clock_info *ptp,
456 			  struct ptp_clock_request *rq, int on)
457 {
458 	struct fec_enet_private *fep =
459 	    container_of(ptp, struct fec_enet_private, ptp_caps);
460 	int ret = 0;
461 
462 	if (rq->type == PTP_CLK_REQ_PPS) {
463 		ret = fec_ptp_enable_pps(fep, on);
464 
465 		return ret;
466 	}
467 	return -EOPNOTSUPP;
468 }
469 
470 /**
471  * fec_ptp_hwtstamp_ioctl - control hardware time stamping
472  * @ndev: pointer to net_device
473  * @ifreq: ioctl data
474  * @cmd: particular ioctl requested
475  */
476 int fec_ptp_set(struct net_device *ndev, struct ifreq *ifr)
477 {
478 	struct fec_enet_private *fep = netdev_priv(ndev);
479 
480 	struct hwtstamp_config config;
481 
482 	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
483 		return -EFAULT;
484 
485 	/* reserved for future extensions */
486 	if (config.flags)
487 		return -EINVAL;
488 
489 	switch (config.tx_type) {
490 	case HWTSTAMP_TX_OFF:
491 		fep->hwts_tx_en = 0;
492 		break;
493 	case HWTSTAMP_TX_ON:
494 		fep->hwts_tx_en = 1;
495 		break;
496 	default:
497 		return -ERANGE;
498 	}
499 
500 	switch (config.rx_filter) {
501 	case HWTSTAMP_FILTER_NONE:
502 		if (fep->hwts_rx_en)
503 			fep->hwts_rx_en = 0;
504 		config.rx_filter = HWTSTAMP_FILTER_NONE;
505 		break;
506 
507 	default:
508 		/*
509 		 * register RXMTRL must be set in order to do V1 packets,
510 		 * therefore it is not possible to time stamp both V1 Sync and
511 		 * Delay_Req messages and hardware does not support
512 		 * timestamping all packets => return error
513 		 */
514 		fep->hwts_rx_en = 1;
515 		config.rx_filter = HWTSTAMP_FILTER_ALL;
516 		break;
517 	}
518 
519 	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
520 	    -EFAULT : 0;
521 }
522 
523 int fec_ptp_get(struct net_device *ndev, struct ifreq *ifr)
524 {
525 	struct fec_enet_private *fep = netdev_priv(ndev);
526 	struct hwtstamp_config config;
527 
528 	config.flags = 0;
529 	config.tx_type = fep->hwts_tx_en ? HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF;
530 	config.rx_filter = (fep->hwts_rx_en ?
531 			    HWTSTAMP_FILTER_ALL : HWTSTAMP_FILTER_NONE);
532 
533 	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
534 		-EFAULT : 0;
535 }
536 
537 /**
538  * fec_time_keep - call timecounter_read every second to avoid timer overrun
539  *                 because ENET just support 32bit counter, will timeout in 4s
540  */
541 static void fec_time_keep(struct work_struct *work)
542 {
543 	struct delayed_work *dwork = to_delayed_work(work);
544 	struct fec_enet_private *fep = container_of(dwork, struct fec_enet_private, time_keep);
545 	u64 ns;
546 	unsigned long flags;
547 
548 	mutex_lock(&fep->ptp_clk_mutex);
549 	if (fep->ptp_clk_on) {
550 		spin_lock_irqsave(&fep->tmreg_lock, flags);
551 		ns = timecounter_read(&fep->tc);
552 		spin_unlock_irqrestore(&fep->tmreg_lock, flags);
553 	}
554 	mutex_unlock(&fep->ptp_clk_mutex);
555 
556 	schedule_delayed_work(&fep->time_keep, HZ);
557 }
558 
559 /**
560  * fec_ptp_init
561  * @ndev: The FEC network adapter
562  *
563  * This function performs the required steps for enabling ptp
564  * support. If ptp support has already been loaded it simply calls the
565  * cyclecounter init routine and exits.
566  */
567 
568 void fec_ptp_init(struct platform_device *pdev)
569 {
570 	struct net_device *ndev = platform_get_drvdata(pdev);
571 	struct fec_enet_private *fep = netdev_priv(ndev);
572 
573 	fep->ptp_caps.owner = THIS_MODULE;
574 	snprintf(fep->ptp_caps.name, 16, "fec ptp");
575 
576 	fep->ptp_caps.max_adj = 250000000;
577 	fep->ptp_caps.n_alarm = 0;
578 	fep->ptp_caps.n_ext_ts = 0;
579 	fep->ptp_caps.n_per_out = 0;
580 	fep->ptp_caps.n_pins = 0;
581 	fep->ptp_caps.pps = 1;
582 	fep->ptp_caps.adjfreq = fec_ptp_adjfreq;
583 	fep->ptp_caps.adjtime = fec_ptp_adjtime;
584 	fep->ptp_caps.gettime64 = fec_ptp_gettime;
585 	fep->ptp_caps.settime64 = fec_ptp_settime;
586 	fep->ptp_caps.enable = fec_ptp_enable;
587 
588 	fep->cycle_speed = clk_get_rate(fep->clk_ptp);
589 	fep->ptp_inc = NSEC_PER_SEC / fep->cycle_speed;
590 
591 	spin_lock_init(&fep->tmreg_lock);
592 
593 	fec_ptp_start_cyclecounter(ndev);
594 
595 	INIT_DELAYED_WORK(&fep->time_keep, fec_time_keep);
596 
597 	fep->ptp_clock = ptp_clock_register(&fep->ptp_caps, &pdev->dev);
598 	if (IS_ERR(fep->ptp_clock)) {
599 		fep->ptp_clock = NULL;
600 		pr_err("ptp_clock_register failed\n");
601 	}
602 
603 	schedule_delayed_work(&fep->time_keep, HZ);
604 }
605 
606 /**
607  * fec_ptp_check_pps_event
608  * @fep: the fec_enet_private structure handle
609  *
610  * This function check the pps event and reload the timer compare counter.
611  */
612 uint fec_ptp_check_pps_event(struct fec_enet_private *fep)
613 {
614 	u32 val;
615 	u8 channel = fep->pps_channel;
616 	struct ptp_clock_event event;
617 
618 	val = readl(fep->hwp + FEC_TCSR(channel));
619 	if (val & FEC_T_TF_MASK) {
620 		/* Write the next next compare(not the next according the spec)
621 		 * value to the register
622 		 */
623 		writel(fep->next_counter, fep->hwp + FEC_TCCR(channel));
624 		do {
625 			writel(val, fep->hwp + FEC_TCSR(channel));
626 		} while (readl(fep->hwp + FEC_TCSR(channel)) & FEC_T_TF_MASK);
627 
628 		/* Update the counter; */
629 		fep->next_counter = (fep->next_counter + fep->reload_period) & fep->cc.mask;
630 
631 		event.type = PTP_CLOCK_PPS;
632 		ptp_clock_event(fep->ptp_clock, &event);
633 		return 1;
634 	}
635 
636 	return 0;
637 }
638