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1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2019 Intel Corporation
4 */
5
6#include <drm/drm_atomic_state_helper.h>
7
8#include "intel_bw.h"
9#include "intel_display_types.h"
10#include "intel_sideband.h"
11
12/* Parameters for Qclk Geyserville (QGV) */
13struct intel_qgv_point {
14 u16 dclk, t_rp, t_rdpre, t_rc, t_ras, t_rcd;
15};
16
17struct intel_qgv_info {
18 struct intel_qgv_point points[3];
19 u8 num_points;
20 u8 num_channels;
21 u8 t_bl;
22 enum intel_dram_type dram_type;
23};
24
25static int icl_pcode_read_mem_global_info(struct drm_i915_private *dev_priv,
26 struct intel_qgv_info *qi)
27{
28 u32 val = 0;
29 int ret;
30
31 ret = sandybridge_pcode_read(dev_priv,
32 ICL_PCODE_MEM_SUBSYSYSTEM_INFO |
33 ICL_PCODE_MEM_SS_READ_GLOBAL_INFO,
34 &val, NULL);
35 if (ret)
36 return ret;
37
38 switch (val & 0xf) {
39 case 0:
40 qi->dram_type = INTEL_DRAM_DDR4;
41 break;
42 case 1:
43 qi->dram_type = INTEL_DRAM_DDR3;
44 break;
45 case 2:
46 qi->dram_type = INTEL_DRAM_LPDDR3;
47 break;
48 case 3:
49 qi->dram_type = INTEL_DRAM_LPDDR3;
50 break;
51 default:
52 MISSING_CASE(val & 0xf);
53 break;
54 }
55
56 qi->num_channels = (val & 0xf0) >> 4;
57 qi->num_points = (val & 0xf00) >> 8;
58
59 qi->t_bl = qi->dram_type == INTEL_DRAM_DDR4 ? 4 : 8;
60
61 return 0;
62}
63
64static int icl_pcode_read_qgv_point_info(struct drm_i915_private *dev_priv,
65 struct intel_qgv_point *sp,
66 int point)
67{
68 u32 val = 0, val2 = 0;
69 int ret;
70
71 ret = sandybridge_pcode_read(dev_priv,
72 ICL_PCODE_MEM_SUBSYSYSTEM_INFO |
73 ICL_PCODE_MEM_SS_READ_QGV_POINT_INFO(point),
74 &val, &val2);
75 if (ret)
76 return ret;
77
78 sp->dclk = val & 0xffff;
79 sp->t_rp = (val & 0xff0000) >> 16;
80 sp->t_rcd = (val & 0xff000000) >> 24;
81
82 sp->t_rdpre = val2 & 0xff;
83 sp->t_ras = (val2 & 0xff00) >> 8;
84
85 sp->t_rc = sp->t_rp + sp->t_ras;
86
87 return 0;
88}
89
90static int icl_get_qgv_points(struct drm_i915_private *dev_priv,
91 struct intel_qgv_info *qi)
92{
93 int i, ret;
94
95 ret = icl_pcode_read_mem_global_info(dev_priv, qi);
96 if (ret)
97 return ret;
98
99 if (WARN_ON(qi->num_points > ARRAY_SIZE(qi->points)))
100 qi->num_points = ARRAY_SIZE(qi->points);
101
102 for (i = 0; i < qi->num_points; i++) {
103 struct intel_qgv_point *sp = &qi->points[i];
104
105 ret = icl_pcode_read_qgv_point_info(dev_priv, sp, i);
106 if (ret)
107 return ret;
108
109 DRM_DEBUG_KMS("QGV %d: DCLK=%d tRP=%d tRDPRE=%d tRAS=%d tRCD=%d tRC=%d\n",
110 i, sp->dclk, sp->t_rp, sp->t_rdpre, sp->t_ras,
111 sp->t_rcd, sp->t_rc);
112 }
113
114 return 0;
115}
116
117static int icl_calc_bw(int dclk, int num, int den)
118{
119 /* multiples of 16.666MHz (100/6) */
120 return DIV_ROUND_CLOSEST(num * dclk * 100, den * 6);
121}
122
123static int icl_sagv_max_dclk(const struct intel_qgv_info *qi)
124{
125 u16 dclk = 0;
126 int i;
127
128 for (i = 0; i < qi->num_points; i++)
129 dclk = max(dclk, qi->points[i].dclk);
130
131 return dclk;
132}
133
134struct intel_sa_info {
135 u8 deburst, mpagesize, deprogbwlimit, displayrtids;
136};
137
138static const struct intel_sa_info icl_sa_info = {
139 .deburst = 8,
140 .mpagesize = 16,
141 .deprogbwlimit = 25, /* GB/s */
142 .displayrtids = 128,
143};
144
145static int icl_get_bw_info(struct drm_i915_private *dev_priv)
146{
147 struct intel_qgv_info qi = {};
148 const struct intel_sa_info *sa = &icl_sa_info;
149 bool is_y_tile = true; /* assume y tile may be used */
150 int num_channels;
151 int deinterleave;
152 int ipqdepth, ipqdepthpch;
153 int dclk_max;
154 int maxdebw;
155 int i, ret;
156
157 ret = icl_get_qgv_points(dev_priv, &qi);
158 if (ret) {
159 DRM_DEBUG_KMS("Failed to get memory subsystem information, ignoring bandwidth limits");
160 return ret;
161 }
162 num_channels = qi.num_channels;
163
164 deinterleave = DIV_ROUND_UP(num_channels, is_y_tile ? 4 : 2);
165 dclk_max = icl_sagv_max_dclk(&qi);
166
167 ipqdepthpch = 16;
168
169 maxdebw = min(sa->deprogbwlimit * 1000,
170 icl_calc_bw(dclk_max, 16, 1) * 6 / 10); /* 60% */
171 ipqdepth = min(ipqdepthpch, sa->displayrtids / num_channels);
172
173 for (i = 0; i < ARRAY_SIZE(dev_priv->max_bw); i++) {
174 struct intel_bw_info *bi = &dev_priv->max_bw[i];
175 int clpchgroup;
176 int j;
177
178 clpchgroup = (sa->deburst * deinterleave / num_channels) << i;
179 bi->num_planes = (ipqdepth - clpchgroup) / clpchgroup + 1;
180
181 bi->num_qgv_points = qi.num_points;
182
183 for (j = 0; j < qi.num_points; j++) {
184 const struct intel_qgv_point *sp = &qi.points[j];
185 int ct, bw;
186
187 /*
188 * Max row cycle time
189 *
190 * FIXME what is the logic behind the
191 * assumed burst length?
192 */
193 ct = max_t(int, sp->t_rc, sp->t_rp + sp->t_rcd +
194 (clpchgroup - 1) * qi.t_bl + sp->t_rdpre);
195 bw = icl_calc_bw(sp->dclk, clpchgroup * 32 * num_channels, ct);
196
197 bi->deratedbw[j] = min(maxdebw,
198 bw * 9 / 10); /* 90% */
199
200 DRM_DEBUG_KMS("BW%d / QGV %d: num_planes=%d deratedbw=%u\n",
201 i, j, bi->num_planes, bi->deratedbw[j]);
202 }
203
204 if (bi->num_planes == 1)
205 break;
206 }
207
208 return 0;
209}
210
211static unsigned int icl_max_bw(struct drm_i915_private *dev_priv,
212 int num_planes, int qgv_point)
213{
214 int i;
215
216 for (i = 0; i < ARRAY_SIZE(dev_priv->max_bw); i++) {
217 const struct intel_bw_info *bi =
218 &dev_priv->max_bw[i];
219
220 /*
221 * Pcode will not expose all QGV points when
222 * SAGV is forced to off/min/med/max.
223 */
224 if (qgv_point >= bi->num_qgv_points)
225 return UINT_MAX;
226
227 if (num_planes >= bi->num_planes)
228 return bi->deratedbw[qgv_point];
229 }
230
231 return 0;
232}
233
234void intel_bw_init_hw(struct drm_i915_private *dev_priv)
235{
236 if (IS_GEN(dev_priv, 11))
237 icl_get_bw_info(dev_priv);
238}
239
240static unsigned int intel_max_data_rate(struct drm_i915_private *dev_priv,
241 int num_planes)
242{
243 if (IS_GEN(dev_priv, 11))
244 /*
245 * FIXME with SAGV disabled maybe we can assume
246 * point 1 will always be used? Seems to match
247 * the behaviour observed in the wild.
248 */
249 return min3(icl_max_bw(dev_priv, num_planes, 0),
250 icl_max_bw(dev_priv, num_planes, 1),
251 icl_max_bw(dev_priv, num_planes, 2));
252 else
253 return UINT_MAX;
254}
255
256static unsigned int intel_bw_crtc_num_active_planes(const struct intel_crtc_state *crtc_state)
257{
258 /*
259 * We assume cursors are small enough
260 * to not not cause bandwidth problems.
261 */
262 return hweight8(crtc_state->active_planes & ~BIT(PLANE_CURSOR));
263}
264
265static unsigned int intel_bw_crtc_data_rate(const struct intel_crtc_state *crtc_state)
266{
267 struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
268 unsigned int data_rate = 0;
269 enum plane_id plane_id;
270
271 for_each_plane_id_on_crtc(crtc, plane_id) {
272 /*
273 * We assume cursors are small enough
274 * to not not cause bandwidth problems.
275 */
276 if (plane_id == PLANE_CURSOR)
277 continue;
278
279 data_rate += crtc_state->data_rate[plane_id];
280 }
281
282 return data_rate;
283}
284
285void intel_bw_crtc_update(struct intel_bw_state *bw_state,
286 const struct intel_crtc_state *crtc_state)
287{
288 struct intel_crtc *crtc = to_intel_crtc(crtc_state->base.crtc);
289
290 bw_state->data_rate[crtc->pipe] =
291 intel_bw_crtc_data_rate(crtc_state);
292 bw_state->num_active_planes[crtc->pipe] =
293 intel_bw_crtc_num_active_planes(crtc_state);
294
295 DRM_DEBUG_KMS("pipe %c data rate %u num active planes %u\n",
296 pipe_name(crtc->pipe),
297 bw_state->data_rate[crtc->pipe],
298 bw_state->num_active_planes[crtc->pipe]);
299}
300
301static unsigned int intel_bw_num_active_planes(struct drm_i915_private *dev_priv,
302 const struct intel_bw_state *bw_state)
303{
304 unsigned int num_active_planes = 0;
305 enum pipe pipe;
306
307 for_each_pipe(dev_priv, pipe)
308 num_active_planes += bw_state->num_active_planes[pipe];
309
310 return num_active_planes;
311}
312
313static unsigned int intel_bw_data_rate(struct drm_i915_private *dev_priv,
314 const struct intel_bw_state *bw_state)
315{
316 unsigned int data_rate = 0;
317 enum pipe pipe;
318
319 for_each_pipe(dev_priv, pipe)
320 data_rate += bw_state->data_rate[pipe];
321
322 return data_rate;
323}
324
325static struct intel_bw_state *
326intel_atomic_get_bw_state(struct intel_atomic_state *state)
327{
328 struct drm_i915_private *dev_priv = to_i915(state->base.dev);
329 struct drm_private_state *bw_state;
330
331 bw_state = drm_atomic_get_private_obj_state(&state->base,
332 &dev_priv->bw_obj);
333 if (IS_ERR(bw_state))
334 return ERR_CAST(bw_state);
335
336 return to_intel_bw_state(bw_state);
337}
338
339int intel_bw_atomic_check(struct intel_atomic_state *state)
340{
341 struct drm_i915_private *dev_priv = to_i915(state->base.dev);
342 struct intel_crtc_state *new_crtc_state, *old_crtc_state;
343 struct intel_bw_state *bw_state = NULL;
344 unsigned int data_rate, max_data_rate;
345 unsigned int num_active_planes;
346 struct intel_crtc *crtc;
347 int i;
348
349 /* FIXME earlier gens need some checks too */
350 if (INTEL_GEN(dev_priv) < 11)
351 return 0;
352
353 for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
354 new_crtc_state, i) {
355 unsigned int old_data_rate =
356 intel_bw_crtc_data_rate(old_crtc_state);
357 unsigned int new_data_rate =
358 intel_bw_crtc_data_rate(new_crtc_state);
359 unsigned int old_active_planes =
360 intel_bw_crtc_num_active_planes(old_crtc_state);
361 unsigned int new_active_planes =
362 intel_bw_crtc_num_active_planes(new_crtc_state);
363
364 /*
365 * Avoid locking the bw state when
366 * nothing significant has changed.
367 */
368 if (old_data_rate == new_data_rate &&
369 old_active_planes == new_active_planes)
370 continue;
371
372 bw_state = intel_atomic_get_bw_state(state);
373 if (IS_ERR(bw_state))
374 return PTR_ERR(bw_state);
375
376 bw_state->data_rate[crtc->pipe] = new_data_rate;
377 bw_state->num_active_planes[crtc->pipe] = new_active_planes;
378
379 DRM_DEBUG_KMS("pipe %c data rate %u num active planes %u\n",
380 pipe_name(crtc->pipe),
381 bw_state->data_rate[crtc->pipe],
382 bw_state->num_active_planes[crtc->pipe]);
383 }
384
385 if (!bw_state)
386 return 0;
387
388 data_rate = intel_bw_data_rate(dev_priv, bw_state);
389 num_active_planes = intel_bw_num_active_planes(dev_priv, bw_state);
390
391 max_data_rate = intel_max_data_rate(dev_priv, num_active_planes);
392
393 data_rate = DIV_ROUND_UP(data_rate, 1000);
394
395 if (data_rate > max_data_rate) {
396 DRM_DEBUG_KMS("Bandwidth %u MB/s exceeds max available %d MB/s (%d active planes)\n",
397 data_rate, max_data_rate, num_active_planes);
398 return -EINVAL;
399 }
400
401 return 0;
402}
403
404static struct drm_private_state *intel_bw_duplicate_state(struct drm_private_obj *obj)
405{
406 struct intel_bw_state *state;
407
408 state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
409 if (!state)
410 return NULL;
411
412 __drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
413
414 return &state->base;
415}
416
417static void intel_bw_destroy_state(struct drm_private_obj *obj,
418 struct drm_private_state *state)
419{
420 kfree(state);
421}
422
423static const struct drm_private_state_funcs intel_bw_funcs = {
424 .atomic_duplicate_state = intel_bw_duplicate_state,
425 .atomic_destroy_state = intel_bw_destroy_state,
426};
427
428int intel_bw_init(struct drm_i915_private *dev_priv)
429{
430 struct intel_bw_state *state;
431
432 state = kzalloc(sizeof(*state), GFP_KERNEL);
433 if (!state)
434 return -ENOMEM;
435
436 drm_atomic_private_obj_init(&dev_priv->drm, &dev_priv->bw_obj,
437 &state->base, &intel_bw_funcs);
438
439 return 0;
440}