1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * 1588 PTP support for Cadence GEM device.
4  *
5  * Copyright (C) 2017 Cadence Design Systems - https://www.cadence.com
6  *
7  * Authors: Rafal Ozieblo <rafalo@cadence.com>
8  *          Bartosz Folta <bfolta@cadence.com>
9  */
10 #include <linux/kernel.h>
11 #include <linux/types.h>
12 #include <linux/clk.h>
13 #include <linux/device.h>
14 #include <linux/etherdevice.h>
15 #include <linux/platform_device.h>
16 #include <linux/time64.h>
17 #include <linux/ptp_classify.h>
18 #include <linux/if_ether.h>
19 #include <linux/if_vlan.h>
20 #include <linux/net_tstamp.h>
21 #include <linux/circ_buf.h>
22 #include <linux/spinlock.h>
23 
24 #include "macb.h"
25 
26 #define  GEM_PTP_TIMER_NAME "gem-ptp-timer"
27 
28 static struct macb_dma_desc_ptp *macb_ptp_desc(struct macb *bp,
29 					       struct macb_dma_desc *desc)
30 {
31 	if (bp->hw_dma_cap == HW_DMA_CAP_PTP)
32 		return (struct macb_dma_desc_ptp *)
33 				((u8 *)desc + sizeof(struct macb_dma_desc));
34 	if (bp->hw_dma_cap == HW_DMA_CAP_64B_PTP)
35 		return (struct macb_dma_desc_ptp *)
36 				((u8 *)desc + sizeof(struct macb_dma_desc)
37 				+ sizeof(struct macb_dma_desc_64));
38 	return NULL;
39 }
40 
41 static int gem_tsu_get_time(struct ptp_clock_info *ptp, struct timespec64 *ts,
42 			    struct ptp_system_timestamp *sts)
43 {
44 	struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
45 	unsigned long flags;
46 	long first, second;
47 	u32 secl, sech;
48 
49 	spin_lock_irqsave(&bp->tsu_clk_lock, flags);
50 	ptp_read_system_prets(sts);
51 	first = gem_readl(bp, TN);
52 	ptp_read_system_postts(sts);
53 	secl = gem_readl(bp, TSL);
54 	sech = gem_readl(bp, TSH);
55 	second = gem_readl(bp, TN);
56 
57 	/* test for nsec rollover */
58 	if (first > second) {
59 		/* if so, use later read & re-read seconds
60 		 * (assume all done within 1s)
61 		 */
62 		ptp_read_system_prets(sts);
63 		ts->tv_nsec = gem_readl(bp, TN);
64 		ptp_read_system_postts(sts);
65 		secl = gem_readl(bp, TSL);
66 		sech = gem_readl(bp, TSH);
67 	} else {
68 		ts->tv_nsec = first;
69 	}
70 
71 	spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);
72 	ts->tv_sec = (((u64)sech << GEM_TSL_SIZE) | secl)
73 			& TSU_SEC_MAX_VAL;
74 	return 0;
75 }
76 
77 static int gem_tsu_set_time(struct ptp_clock_info *ptp,
78 			    const struct timespec64 *ts)
79 {
80 	struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
81 	unsigned long flags;
82 	u32 ns, sech, secl;
83 
84 	secl = (u32)ts->tv_sec;
85 	sech = (ts->tv_sec >> GEM_TSL_SIZE) & ((1 << GEM_TSH_SIZE) - 1);
86 	ns = ts->tv_nsec;
87 
88 	spin_lock_irqsave(&bp->tsu_clk_lock, flags);
89 
90 	/* TSH doesn't latch the time and no atomicity! */
91 	gem_writel(bp, TN, 0); /* clear to avoid overflow */
92 	gem_writel(bp, TSH, sech);
93 	/* write lower bits 2nd, for synchronized secs update */
94 	gem_writel(bp, TSL, secl);
95 	gem_writel(bp, TN, ns);
96 
97 	spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);
98 
99 	return 0;
100 }
101 
102 static int gem_tsu_incr_set(struct macb *bp, struct tsu_incr *incr_spec)
103 {
104 	unsigned long flags;
105 
106 	/* tsu_timer_incr register must be written after
107 	 * the tsu_timer_incr_sub_ns register and the write operation
108 	 * will cause the value written to the tsu_timer_incr_sub_ns register
109 	 * to take effect.
110 	 */
111 	spin_lock_irqsave(&bp->tsu_clk_lock, flags);
112 	/* RegBit[15:0] = Subns[23:8]; RegBit[31:24] = Subns[7:0] */
113 	gem_writel(bp, TISUBN, GEM_BF(SUBNSINCRL, incr_spec->sub_ns) |
114 		   GEM_BF(SUBNSINCRH, (incr_spec->sub_ns >>
115 			  GEM_SUBNSINCRL_SIZE)));
116 	gem_writel(bp, TI, GEM_BF(NSINCR, incr_spec->ns));
117 	spin_unlock_irqrestore(&bp->tsu_clk_lock, flags);
118 
119 	return 0;
120 }
121 
122 static int gem_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
123 {
124 	struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
125 	struct tsu_incr incr_spec;
126 	bool neg_adj = false;
127 	u32 word;
128 	u64 adj;
129 
130 	if (scaled_ppm < 0) {
131 		neg_adj = true;
132 		scaled_ppm = -scaled_ppm;
133 	}
134 
135 	/* Adjustment is relative to base frequency */
136 	incr_spec.sub_ns = bp->tsu_incr.sub_ns;
137 	incr_spec.ns = bp->tsu_incr.ns;
138 
139 	/* scaling: unused(8bit) | ns(8bit) | fractions(16bit) */
140 	word = ((u64)incr_spec.ns << GEM_SUBNSINCR_SIZE) + incr_spec.sub_ns;
141 	adj = (u64)scaled_ppm * word;
142 	/* Divide with rounding, equivalent to floating dividing:
143 	 * (temp / USEC_PER_SEC) + 0.5
144 	 */
145 	adj += (USEC_PER_SEC >> 1);
146 	adj >>= PPM_FRACTION; /* remove fractions */
147 	adj = div_u64(adj, USEC_PER_SEC);
148 	adj = neg_adj ? (word - adj) : (word + adj);
149 
150 	incr_spec.ns = (adj >> GEM_SUBNSINCR_SIZE)
151 			& ((1 << GEM_NSINCR_SIZE) - 1);
152 	incr_spec.sub_ns = adj & ((1 << GEM_SUBNSINCR_SIZE) - 1);
153 	gem_tsu_incr_set(bp, &incr_spec);
154 	return 0;
155 }
156 
157 static int gem_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
158 {
159 	struct macb *bp = container_of(ptp, struct macb, ptp_clock_info);
160 	struct timespec64 now, then = ns_to_timespec64(delta);
161 	u32 adj, sign = 0;
162 
163 	if (delta < 0) {
164 		sign = 1;
165 		delta = -delta;
166 	}
167 
168 	if (delta > TSU_NSEC_MAX_VAL) {
169 		gem_tsu_get_time(&bp->ptp_clock_info, &now, NULL);
170 		now = timespec64_add(now, then);
171 
172 		gem_tsu_set_time(&bp->ptp_clock_info,
173 				 (const struct timespec64 *)&now);
174 	} else {
175 		adj = (sign << GEM_ADDSUB_OFFSET) | delta;
176 
177 		gem_writel(bp, TA, adj);
178 	}
179 
180 	return 0;
181 }
182 
183 static int gem_ptp_enable(struct ptp_clock_info *ptp,
184 			  struct ptp_clock_request *rq, int on)
185 {
186 	return -EOPNOTSUPP;
187 }
188 
189 static const struct ptp_clock_info gem_ptp_caps_template = {
190 	.owner		= THIS_MODULE,
191 	.name		= GEM_PTP_TIMER_NAME,
192 	.max_adj	= 0,
193 	.n_alarm	= 0,
194 	.n_ext_ts	= 0,
195 	.n_per_out	= 0,
196 	.n_pins		= 0,
197 	.pps		= 1,
198 	.adjfine	= gem_ptp_adjfine,
199 	.adjtime	= gem_ptp_adjtime,
200 	.gettimex64	= gem_tsu_get_time,
201 	.settime64	= gem_tsu_set_time,
202 	.enable		= gem_ptp_enable,
203 };
204 
205 static void gem_ptp_init_timer(struct macb *bp)
206 {
207 	u32 rem = 0;
208 	u64 adj;
209 
210 	bp->tsu_incr.ns = div_u64_rem(NSEC_PER_SEC, bp->tsu_rate, &rem);
211 	if (rem) {
212 		adj = rem;
213 		adj <<= GEM_SUBNSINCR_SIZE;
214 		bp->tsu_incr.sub_ns = div_u64(adj, bp->tsu_rate);
215 	} else {
216 		bp->tsu_incr.sub_ns = 0;
217 	}
218 }
219 
220 static void gem_ptp_init_tsu(struct macb *bp)
221 {
222 	struct timespec64 ts;
223 
224 	/* 1. get current system time */
225 	ts = ns_to_timespec64(ktime_to_ns(ktime_get_real()));
226 
227 	/* 2. set ptp timer */
228 	gem_tsu_set_time(&bp->ptp_clock_info, &ts);
229 
230 	/* 3. set PTP timer increment value to BASE_INCREMENT */
231 	gem_tsu_incr_set(bp, &bp->tsu_incr);
232 
233 	gem_writel(bp, TA, 0);
234 }
235 
236 static void gem_ptp_clear_timer(struct macb *bp)
237 {
238 	bp->tsu_incr.sub_ns = 0;
239 	bp->tsu_incr.ns = 0;
240 
241 	gem_writel(bp, TISUBN, GEM_BF(SUBNSINCR, 0));
242 	gem_writel(bp, TI, GEM_BF(NSINCR, 0));
243 	gem_writel(bp, TA, 0);
244 }
245 
246 static int gem_hw_timestamp(struct macb *bp, u32 dma_desc_ts_1,
247 			    u32 dma_desc_ts_2, struct timespec64 *ts)
248 {
249 	struct timespec64 tsu;
250 
251 	ts->tv_sec = (GEM_BFEXT(DMA_SECH, dma_desc_ts_2) << GEM_DMA_SECL_SIZE) |
252 			GEM_BFEXT(DMA_SECL, dma_desc_ts_1);
253 	ts->tv_nsec = GEM_BFEXT(DMA_NSEC, dma_desc_ts_1);
254 
255 	/* TSU overlapping workaround
256 	 * The timestamp only contains lower few bits of seconds,
257 	 * so add value from 1588 timer
258 	 */
259 	gem_tsu_get_time(&bp->ptp_clock_info, &tsu, NULL);
260 
261 	/* If the top bit is set in the timestamp,
262 	 * but not in 1588 timer, it has rolled over,
263 	 * so subtract max size
264 	 */
265 	if ((ts->tv_sec & (GEM_DMA_SEC_TOP >> 1)) &&
266 	    !(tsu.tv_sec & (GEM_DMA_SEC_TOP >> 1)))
267 		ts->tv_sec -= GEM_DMA_SEC_TOP;
268 
269 	ts->tv_sec += ((~GEM_DMA_SEC_MASK) & tsu.tv_sec);
270 
271 	return 0;
272 }
273 
274 void gem_ptp_rxstamp(struct macb *bp, struct sk_buff *skb,
275 		     struct macb_dma_desc *desc)
276 {
277 	struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
278 	struct macb_dma_desc_ptp *desc_ptp;
279 	struct timespec64 ts;
280 
281 	if (GEM_BFEXT(DMA_RXVALID, desc->addr)) {
282 		desc_ptp = macb_ptp_desc(bp, desc);
283 		/* Unlikely but check */
284 		if (!desc_ptp) {
285 			dev_warn_ratelimited(&bp->pdev->dev,
286 					     "Timestamp not supported in BD\n");
287 			return;
288 		}
289 		gem_hw_timestamp(bp, desc_ptp->ts_1, desc_ptp->ts_2, &ts);
290 		memset(shhwtstamps, 0, sizeof(struct skb_shared_hwtstamps));
291 		shhwtstamps->hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
292 	}
293 }
294 
295 static void gem_tstamp_tx(struct macb *bp, struct sk_buff *skb,
296 			  struct macb_dma_desc_ptp *desc_ptp)
297 {
298 	struct skb_shared_hwtstamps shhwtstamps;
299 	struct timespec64 ts;
300 
301 	gem_hw_timestamp(bp, desc_ptp->ts_1, desc_ptp->ts_2, &ts);
302 	memset(&shhwtstamps, 0, sizeof(shhwtstamps));
303 	shhwtstamps.hwtstamp = ktime_set(ts.tv_sec, ts.tv_nsec);
304 	skb_tstamp_tx(skb, &shhwtstamps);
305 }
306 
307 int gem_ptp_txstamp(struct macb_queue *queue, struct sk_buff *skb,
308 		    struct macb_dma_desc *desc)
309 {
310 	unsigned long tail = READ_ONCE(queue->tx_ts_tail);
311 	unsigned long head = queue->tx_ts_head;
312 	struct macb_dma_desc_ptp *desc_ptp;
313 	struct gem_tx_ts *tx_timestamp;
314 
315 	if (!GEM_BFEXT(DMA_TXVALID, desc->ctrl))
316 		return -EINVAL;
317 
318 	if (CIRC_SPACE(head, tail, PTP_TS_BUFFER_SIZE) == 0)
319 		return -ENOMEM;
320 
321 	desc_ptp = macb_ptp_desc(queue->bp, desc);
322 	/* Unlikely but check */
323 	if (!desc_ptp)
324 		return -EINVAL;
325 	skb_shinfo(skb)->tx_flags |= SKBTX_IN_PROGRESS;
326 	tx_timestamp = &queue->tx_timestamps[head];
327 	tx_timestamp->skb = skb;
328 	/* ensure ts_1/ts_2 is loaded after ctrl (TX_USED check) */
329 	dma_rmb();
330 	tx_timestamp->desc_ptp.ts_1 = desc_ptp->ts_1;
331 	tx_timestamp->desc_ptp.ts_2 = desc_ptp->ts_2;
332 	/* move head */
333 	smp_store_release(&queue->tx_ts_head,
334 			  (head + 1) & (PTP_TS_BUFFER_SIZE - 1));
335 
336 	schedule_work(&queue->tx_ts_task);
337 	return 0;
338 }
339 
340 static void gem_tx_timestamp_flush(struct work_struct *work)
341 {
342 	struct macb_queue *queue =
343 			container_of(work, struct macb_queue, tx_ts_task);
344 	unsigned long head, tail;
345 	struct gem_tx_ts *tx_ts;
346 
347 	/* take current head */
348 	head = smp_load_acquire(&queue->tx_ts_head);
349 	tail = queue->tx_ts_tail;
350 
351 	while (CIRC_CNT(head, tail, PTP_TS_BUFFER_SIZE)) {
352 		tx_ts = &queue->tx_timestamps[tail];
353 		gem_tstamp_tx(queue->bp, tx_ts->skb, &tx_ts->desc_ptp);
354 		/* cleanup */
355 		dev_kfree_skb_any(tx_ts->skb);
356 		/* remove old tail */
357 		smp_store_release(&queue->tx_ts_tail,
358 				  (tail + 1) & (PTP_TS_BUFFER_SIZE - 1));
359 		tail = queue->tx_ts_tail;
360 	}
361 }
362 
363 void gem_ptp_init(struct net_device *dev)
364 {
365 	struct macb *bp = netdev_priv(dev);
366 	struct macb_queue *queue;
367 	unsigned int q;
368 
369 	bp->ptp_clock_info = gem_ptp_caps_template;
370 
371 	/* nominal frequency and maximum adjustment in ppb */
372 	bp->tsu_rate = bp->ptp_info->get_tsu_rate(bp);
373 	bp->ptp_clock_info.max_adj = bp->ptp_info->get_ptp_max_adj();
374 	gem_ptp_init_timer(bp);
375 	bp->ptp_clock = ptp_clock_register(&bp->ptp_clock_info, &dev->dev);
376 	if (IS_ERR(bp->ptp_clock)) {
377 		pr_err("ptp clock register failed: %ld\n",
378 			PTR_ERR(bp->ptp_clock));
379 		bp->ptp_clock = NULL;
380 		return;
381 	} else if (bp->ptp_clock == NULL) {
382 		pr_err("ptp clock register failed\n");
383 		return;
384 	}
385 
386 	spin_lock_init(&bp->tsu_clk_lock);
387 	for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
388 		queue->tx_ts_head = 0;
389 		queue->tx_ts_tail = 0;
390 		INIT_WORK(&queue->tx_ts_task, gem_tx_timestamp_flush);
391 	}
392 
393 	gem_ptp_init_tsu(bp);
394 
395 	dev_info(&bp->pdev->dev, "%s ptp clock registered.\n",
396 		 GEM_PTP_TIMER_NAME);
397 }
398 
399 void gem_ptp_remove(struct net_device *ndev)
400 {
401 	struct macb *bp = netdev_priv(ndev);
402 
403 	if (bp->ptp_clock)
404 		ptp_clock_unregister(bp->ptp_clock);
405 
406 	gem_ptp_clear_timer(bp);
407 
408 	dev_info(&bp->pdev->dev, "%s ptp clock unregistered.\n",
409 		 GEM_PTP_TIMER_NAME);
410 }
411 
412 static int gem_ptp_set_ts_mode(struct macb *bp,
413 			       enum macb_bd_control tx_bd_control,
414 			       enum macb_bd_control rx_bd_control)
415 {
416 	gem_writel(bp, TXBDCTRL, GEM_BF(TXTSMODE, tx_bd_control));
417 	gem_writel(bp, RXBDCTRL, GEM_BF(RXTSMODE, rx_bd_control));
418 
419 	return 0;
420 }
421 
422 int gem_get_hwtst(struct net_device *dev, struct ifreq *rq)
423 {
424 	struct hwtstamp_config *tstamp_config;
425 	struct macb *bp = netdev_priv(dev);
426 
427 	tstamp_config = &bp->tstamp_config;
428 	if ((bp->hw_dma_cap & HW_DMA_CAP_PTP) == 0)
429 		return -EOPNOTSUPP;
430 
431 	if (copy_to_user(rq->ifr_data, tstamp_config, sizeof(*tstamp_config)))
432 		return -EFAULT;
433 	else
434 		return 0;
435 }
436 
437 static int gem_ptp_set_one_step_sync(struct macb *bp, u8 enable)
438 {
439 	u32 reg_val;
440 
441 	reg_val = macb_readl(bp, NCR);
442 
443 	if (enable)
444 		macb_writel(bp, NCR, reg_val | MACB_BIT(OSSMODE));
445 	else
446 		macb_writel(bp, NCR, reg_val & ~MACB_BIT(OSSMODE));
447 
448 	return 0;
449 }
450 
451 int gem_set_hwtst(struct net_device *dev, struct ifreq *ifr, int cmd)
452 {
453 	enum macb_bd_control tx_bd_control = TSTAMP_DISABLED;
454 	enum macb_bd_control rx_bd_control = TSTAMP_DISABLED;
455 	struct hwtstamp_config *tstamp_config;
456 	struct macb *bp = netdev_priv(dev);
457 	u32 regval;
458 
459 	tstamp_config = &bp->tstamp_config;
460 	if ((bp->hw_dma_cap & HW_DMA_CAP_PTP) == 0)
461 		return -EOPNOTSUPP;
462 
463 	if (copy_from_user(tstamp_config, ifr->ifr_data,
464 			   sizeof(*tstamp_config)))
465 		return -EFAULT;
466 
467 	/* reserved for future extensions */
468 	if (tstamp_config->flags)
469 		return -EINVAL;
470 
471 	switch (tstamp_config->tx_type) {
472 	case HWTSTAMP_TX_OFF:
473 		break;
474 	case HWTSTAMP_TX_ONESTEP_SYNC:
475 		if (gem_ptp_set_one_step_sync(bp, 1) != 0)
476 			return -ERANGE;
477 		fallthrough;
478 	case HWTSTAMP_TX_ON:
479 		tx_bd_control = TSTAMP_ALL_FRAMES;
480 		break;
481 	default:
482 		return -ERANGE;
483 	}
484 
485 	switch (tstamp_config->rx_filter) {
486 	case HWTSTAMP_FILTER_NONE:
487 		break;
488 	case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
489 		break;
490 	case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
491 		break;
492 	case HWTSTAMP_FILTER_PTP_V2_EVENT:
493 	case HWTSTAMP_FILTER_PTP_V2_L2_EVENT:
494 	case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
495 	case HWTSTAMP_FILTER_PTP_V2_SYNC:
496 	case HWTSTAMP_FILTER_PTP_V2_L2_SYNC:
497 	case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
498 	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
499 	case HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ:
500 	case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
501 		rx_bd_control =  TSTAMP_ALL_PTP_FRAMES;
502 		tstamp_config->rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
503 		regval = macb_readl(bp, NCR);
504 		macb_writel(bp, NCR, (regval | MACB_BIT(SRTSM)));
505 		break;
506 	case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
507 	case HWTSTAMP_FILTER_ALL:
508 		rx_bd_control = TSTAMP_ALL_FRAMES;
509 		tstamp_config->rx_filter = HWTSTAMP_FILTER_ALL;
510 		break;
511 	default:
512 		tstamp_config->rx_filter = HWTSTAMP_FILTER_NONE;
513 		return -ERANGE;
514 	}
515 
516 	if (gem_ptp_set_ts_mode(bp, tx_bd_control, rx_bd_control) != 0)
517 		return -ERANGE;
518 
519 	if (copy_to_user(ifr->ifr_data, tstamp_config, sizeof(*tstamp_config)))
520 		return -EFAULT;
521 	else
522 		return 0;
523 }
524 
525