1// SPDX-License-Identifier: GPL-2.0
2/* Copyright (C) 2021 Gerhard Engleder <gerhard@engleder-embedded.com> */
3
4#include "tsnep.h"
5
6#include <net/pkt_sched.h>
7
8/* save one operation at the end for additional operation at list change */
9#define TSNEP_MAX_GCL_NUM (TSNEP_GCL_COUNT - 1)
10
11static int tsnep_validate_gcl(struct tc_taprio_qopt_offload *qopt)
12{
13 int i;
14 u64 cycle_time;
15
16 if (!qopt->cycle_time)
17 return -ERANGE;
18 if (qopt->num_entries > TSNEP_MAX_GCL_NUM)
19 return -EINVAL;
20 cycle_time = 0;
21 for (i = 0; i < qopt->num_entries; i++) {
22 if (qopt->entries[i].command != TC_TAPRIO_CMD_SET_GATES)
23 return -EINVAL;
24 if (qopt->entries[i].gate_mask & ~TSNEP_GCL_MASK)
25 return -EINVAL;
26 if (qopt->entries[i].interval < TSNEP_GCL_MIN_INTERVAL)
27 return -EINVAL;
28 cycle_time += qopt->entries[i].interval;
29 }
30 if (qopt->cycle_time != cycle_time)
31 return -EINVAL;
32 if (qopt->cycle_time_extension >= qopt->cycle_time)
33 return -EINVAL;
34
35 return 0;
36}
37
38static void tsnep_write_gcl_operation(struct tsnep_gcl *gcl, int index,
39 u32 properties, u32 interval, bool flush)
40{
41 void __iomem *addr = gcl->addr +
42 sizeof(struct tsnep_gcl_operation) * index;
43
44 gcl->operation[index].properties = properties;
45 gcl->operation[index].interval = interval;
46
47 iowrite32(properties, addr);
48 iowrite32(interval, addr + sizeof(u32));
49
50 if (flush) {
51 /* flush write with read access */
52 ioread32(addr);
53 }
54}
55
56static u64 tsnep_change_duration(struct tsnep_gcl *gcl, int index)
57{
58 u64 duration;
59 int count;
60
61 /* change needs to be triggered one or two operations before start of
62 * new gate control list
63 * - change is triggered at start of operation (minimum one operation)
64 * - operation with adjusted interval is inserted on demand to exactly
65 * meet the start of the new gate control list (optional)
66 *
67 * additionally properties are read directly after start of previous
68 * operation
69 *
70 * therefore, three operations needs to be considered for the limit
71 */
72 duration = 0;
73 count = 3;
74 while (count) {
75 duration += gcl->operation[index].interval;
76
77 index--;
78 if (index < 0)
79 index = gcl->count - 1;
80
81 count--;
82 }
83
84 return duration;
85}
86
87static void tsnep_write_gcl(struct tsnep_gcl *gcl,
88 struct tc_taprio_qopt_offload *qopt)
89{
90 int i;
91 u32 properties;
92 u64 extend;
93 u64 cut;
94
95 gcl->base_time = ktime_to_ns(kt: qopt->base_time);
96 gcl->cycle_time = qopt->cycle_time;
97 gcl->cycle_time_extension = qopt->cycle_time_extension;
98
99 for (i = 0; i < qopt->num_entries; i++) {
100 properties = qopt->entries[i].gate_mask;
101 if (i == (qopt->num_entries - 1))
102 properties |= TSNEP_GCL_LAST;
103
104 tsnep_write_gcl_operation(gcl, index: i, properties,
105 interval: qopt->entries[i].interval, flush: true);
106 }
107 gcl->count = qopt->num_entries;
108
109 /* calculate change limit; i.e., the time needed between enable and
110 * start of new gate control list
111 */
112
113 /* case 1: extend cycle time for change
114 * - change duration of last operation
115 * - cycle time extension
116 */
117 extend = tsnep_change_duration(gcl, index: gcl->count - 1);
118 extend += gcl->cycle_time_extension;
119
120 /* case 2: cut cycle time for change
121 * - maximum change duration
122 */
123 cut = 0;
124 for (i = 0; i < gcl->count; i++)
125 cut = max(cut, tsnep_change_duration(gcl, i));
126
127 /* use maximum, because the actual case (extend or cut) can be
128 * determined only after limit is known (chicken-and-egg problem)
129 */
130 gcl->change_limit = max(extend, cut);
131}
132
133static u64 tsnep_gcl_start_after(struct tsnep_gcl *gcl, u64 limit)
134{
135 u64 start = gcl->base_time;
136 u64 n;
137
138 if (start <= limit) {
139 n = div64_u64(dividend: limit - start, divisor: gcl->cycle_time);
140 start += (n + 1) * gcl->cycle_time;
141 }
142
143 return start;
144}
145
146static u64 tsnep_gcl_start_before(struct tsnep_gcl *gcl, u64 limit)
147{
148 u64 start = gcl->base_time;
149 u64 n;
150
151 n = div64_u64(dividend: limit - start, divisor: gcl->cycle_time);
152 start += n * gcl->cycle_time;
153 if (start == limit)
154 start -= gcl->cycle_time;
155
156 return start;
157}
158
159static u64 tsnep_set_gcl_change(struct tsnep_gcl *gcl, int index, u64 change,
160 bool insert)
161{
162 /* previous operation triggers change and properties are evaluated at
163 * start of operation
164 */
165 if (index == 0)
166 index = gcl->count - 1;
167 else
168 index = index - 1;
169 change -= gcl->operation[index].interval;
170
171 /* optionally change to new list with additional operation in between */
172 if (insert) {
173 void __iomem *addr = gcl->addr +
174 sizeof(struct tsnep_gcl_operation) * index;
175
176 gcl->operation[index].properties |= TSNEP_GCL_INSERT;
177 iowrite32(gcl->operation[index].properties, addr);
178 }
179
180 return change;
181}
182
183static void tsnep_clean_gcl(struct tsnep_gcl *gcl)
184{
185 int i;
186 u32 mask = TSNEP_GCL_LAST | TSNEP_GCL_MASK;
187 void __iomem *addr;
188
189 /* search for insert operation and reset properties */
190 for (i = 0; i < gcl->count; i++) {
191 if (gcl->operation[i].properties & ~mask) {
192 addr = gcl->addr +
193 sizeof(struct tsnep_gcl_operation) * i;
194
195 gcl->operation[i].properties &= mask;
196 iowrite32(gcl->operation[i].properties, addr);
197
198 break;
199 }
200 }
201}
202
203static u64 tsnep_insert_gcl_operation(struct tsnep_gcl *gcl, int ref,
204 u64 change, u32 interval)
205{
206 u32 properties;
207
208 properties = gcl->operation[ref].properties & TSNEP_GCL_MASK;
209 /* change to new list directly after inserted operation */
210 properties |= TSNEP_GCL_CHANGE;
211
212 /* last operation of list is reserved to insert operation */
213 tsnep_write_gcl_operation(gcl, TSNEP_GCL_COUNT - 1, properties,
214 interval, flush: false);
215
216 return tsnep_set_gcl_change(gcl, index: ref, change, insert: true);
217}
218
219static u64 tsnep_extend_gcl(struct tsnep_gcl *gcl, u64 start, u32 extension)
220{
221 int ref = gcl->count - 1;
222 u32 interval = gcl->operation[ref].interval + extension;
223
224 start -= gcl->operation[ref].interval;
225
226 return tsnep_insert_gcl_operation(gcl, ref, change: start, interval);
227}
228
229static u64 tsnep_cut_gcl(struct tsnep_gcl *gcl, u64 start, u64 cycle_time)
230{
231 u64 sum = 0;
232 int i;
233
234 /* find operation which shall be cutted */
235 for (i = 0; i < gcl->count; i++) {
236 u64 sum_tmp = sum + gcl->operation[i].interval;
237 u64 interval;
238
239 /* sum up operations as long as cycle time is not exceeded */
240 if (sum_tmp > cycle_time)
241 break;
242
243 /* remaining interval must be big enough for hardware */
244 interval = cycle_time - sum_tmp;
245 if (interval > 0 && interval < TSNEP_GCL_MIN_INTERVAL)
246 break;
247
248 sum = sum_tmp;
249 }
250 if (sum == cycle_time) {
251 /* no need to cut operation itself or whole cycle
252 * => change exactly at operation
253 */
254 return tsnep_set_gcl_change(gcl, index: i, change: start + sum, insert: false);
255 }
256 return tsnep_insert_gcl_operation(gcl, ref: i, change: start + sum,
257 interval: cycle_time - sum);
258}
259
260static int tsnep_enable_gcl(struct tsnep_adapter *adapter,
261 struct tsnep_gcl *gcl, struct tsnep_gcl *curr)
262{
263 u64 system_time;
264 u64 timeout;
265 u64 limit;
266
267 /* estimate timeout limit after timeout enable, actually timeout limit
268 * in hardware will be earlier than estimate so we are on the safe side
269 */
270 tsnep_get_system_time(adapter, time: &system_time);
271 timeout = system_time + TSNEP_GC_TIMEOUT;
272
273 if (curr)
274 limit = timeout + curr->change_limit;
275 else
276 limit = timeout;
277
278 gcl->start_time = tsnep_gcl_start_after(gcl, limit);
279
280 /* gate control time register is only 32bit => time shall be in the near
281 * future (no driver support for far future implemented)
282 */
283 if ((gcl->start_time - system_time) >= U32_MAX)
284 return -EAGAIN;
285
286 if (curr) {
287 /* change gate control list */
288 u64 last;
289 u64 change;
290
291 last = tsnep_gcl_start_before(gcl: curr, limit: gcl->start_time);
292 if ((last + curr->cycle_time) == gcl->start_time)
293 change = tsnep_cut_gcl(gcl: curr, start: last,
294 cycle_time: gcl->start_time - last);
295 else if (((gcl->start_time - last) <=
296 curr->cycle_time_extension) ||
297 ((gcl->start_time - last) <= TSNEP_GCL_MIN_INTERVAL))
298 change = tsnep_extend_gcl(gcl: curr, start: last,
299 extension: gcl->start_time - last);
300 else
301 change = tsnep_cut_gcl(gcl: curr, start: last,
302 cycle_time: gcl->start_time - last);
303
304 WARN_ON(change <= timeout);
305 gcl->change = true;
306 iowrite32(change & 0xFFFFFFFF, adapter->addr + TSNEP_GC_CHANGE);
307 } else {
308 /* start gate control list */
309 WARN_ON(gcl->start_time <= timeout);
310 gcl->change = false;
311 iowrite32(gcl->start_time & 0xFFFFFFFF,
312 adapter->addr + TSNEP_GC_TIME);
313 }
314
315 return 0;
316}
317
318static int tsnep_taprio(struct tsnep_adapter *adapter,
319 struct tc_taprio_qopt_offload *qopt)
320{
321 struct tsnep_gcl *gcl;
322 struct tsnep_gcl *curr;
323 int retval;
324
325 if (!adapter->gate_control)
326 return -EOPNOTSUPP;
327
328 if (qopt->cmd == TAPRIO_CMD_DESTROY) {
329 /* disable gate control if active */
330 mutex_lock(&adapter->gate_control_lock);
331
332 if (adapter->gate_control_active) {
333 iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
334 adapter->gate_control_active = false;
335 }
336
337 mutex_unlock(lock: &adapter->gate_control_lock);
338
339 return 0;
340 } else if (qopt->cmd != TAPRIO_CMD_REPLACE) {
341 return -EOPNOTSUPP;
342 }
343
344 retval = tsnep_validate_gcl(qopt);
345 if (retval)
346 return retval;
347
348 mutex_lock(&adapter->gate_control_lock);
349
350 gcl = &adapter->gcl[adapter->next_gcl];
351 tsnep_write_gcl(gcl, qopt);
352
353 /* select current gate control list if active */
354 if (adapter->gate_control_active) {
355 if (adapter->next_gcl == 0)
356 curr = &adapter->gcl[1];
357 else
358 curr = &adapter->gcl[0];
359 } else {
360 curr = NULL;
361 }
362
363 for (;;) {
364 /* start timeout which discards late enable, this helps ensuring
365 * that start/change time are in the future at enable
366 */
367 iowrite8(TSNEP_GC_ENABLE_TIMEOUT, adapter->addr + TSNEP_GC);
368
369 retval = tsnep_enable_gcl(adapter, gcl, curr);
370 if (retval) {
371 mutex_unlock(lock: &adapter->gate_control_lock);
372
373 return retval;
374 }
375
376 /* enable gate control list */
377 if (adapter->next_gcl == 0)
378 iowrite8(TSNEP_GC_ENABLE_A, adapter->addr + TSNEP_GC);
379 else
380 iowrite8(TSNEP_GC_ENABLE_B, adapter->addr + TSNEP_GC);
381
382 /* done if timeout did not happen */
383 if (!(ioread32(adapter->addr + TSNEP_GC) &
384 TSNEP_GC_TIMEOUT_SIGNAL))
385 break;
386
387 /* timeout is acknowledged with any enable */
388 iowrite8(TSNEP_GC_ENABLE_A, adapter->addr + TSNEP_GC);
389
390 if (curr)
391 tsnep_clean_gcl(gcl: curr);
392
393 /* retry because of timeout */
394 }
395
396 adapter->gate_control_active = true;
397
398 if (adapter->next_gcl == 0)
399 adapter->next_gcl = 1;
400 else
401 adapter->next_gcl = 0;
402
403 mutex_unlock(lock: &adapter->gate_control_lock);
404
405 return 0;
406}
407
408static int tsnep_tc_query_caps(struct tsnep_adapter *adapter,
409 struct tc_query_caps_base *base)
410{
411 switch (base->type) {
412 case TC_SETUP_QDISC_TAPRIO: {
413 struct tc_taprio_caps *caps = base->caps;
414
415 if (!adapter->gate_control)
416 return -EOPNOTSUPP;
417
418 caps->gate_mask_per_txq = true;
419
420 return 0;
421 }
422 default:
423 return -EOPNOTSUPP;
424 }
425}
426
427int tsnep_tc_setup(struct net_device *netdev, enum tc_setup_type type,
428 void *type_data)
429{
430 struct tsnep_adapter *adapter = netdev_priv(dev: netdev);
431
432 switch (type) {
433 case TC_QUERY_CAPS:
434 return tsnep_tc_query_caps(adapter, base: type_data);
435 case TC_SETUP_QDISC_TAPRIO:
436 return tsnep_taprio(adapter, qopt: type_data);
437 default:
438 return -EOPNOTSUPP;
439 }
440}
441
442int tsnep_tc_init(struct tsnep_adapter *adapter)
443{
444 if (!adapter->gate_control)
445 return 0;
446
447 /* open all gates */
448 iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
449 iowrite32(TSNEP_GC_OPEN | TSNEP_GC_NEXT_OPEN, adapter->addr + TSNEP_GC);
450
451 adapter->gcl[0].addr = adapter->addr + TSNEP_GCL_A;
452 adapter->gcl[1].addr = adapter->addr + TSNEP_GCL_B;
453
454 return 0;
455}
456
457void tsnep_tc_cleanup(struct tsnep_adapter *adapter)
458{
459 if (!adapter->gate_control)
460 return;
461
462 if (adapter->gate_control_active) {
463 iowrite8(TSNEP_GC_DISABLE, adapter->addr + TSNEP_GC);
464 adapter->gate_control_active = false;
465 }
466}
467

source code of linux/drivers/net/ethernet/engleder/tsnep_tc.c