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Diffstat (limited to 'drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c')
-rw-r--r--drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c350
1 files changed, 350 insertions, 0 deletions
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c
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+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pll.c
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1/*
2 * Copyright 2014 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 */
23#include <drm/drmP.h>
24#include <drm/amdgpu_drm.h>
25#include "amdgpu.h"
26#include "atom.h"
27#include "atombios_encoders.h"
28#include <asm/div64.h>
29#include <linux/gcd.h>
30
31/**
32 * amdgpu_pll_reduce_ratio - fractional number reduction
33 *
34 * @nom: nominator
35 * @den: denominator
36 * @nom_min: minimum value for nominator
37 * @den_min: minimum value for denominator
38 *
39 * Find the greatest common divisor and apply it on both nominator and
40 * denominator, but make nominator and denominator are at least as large
41 * as their minimum values.
42 */
43static void amdgpu_pll_reduce_ratio(unsigned *nom, unsigned *den,
44 unsigned nom_min, unsigned den_min)
45{
46 unsigned tmp;
47
48 /* reduce the numbers to a simpler ratio */
49 tmp = gcd(*nom, *den);
50 *nom /= tmp;
51 *den /= tmp;
52
53 /* make sure nominator is large enough */
54 if (*nom < nom_min) {
55 tmp = DIV_ROUND_UP(nom_min, *nom);
56 *nom *= tmp;
57 *den *= tmp;
58 }
59
60 /* make sure the denominator is large enough */
61 if (*den < den_min) {
62 tmp = DIV_ROUND_UP(den_min, *den);
63 *nom *= tmp;
64 *den *= tmp;
65 }
66}
67
68/**
69 * amdgpu_pll_get_fb_ref_div - feedback and ref divider calculation
70 *
71 * @nom: nominator
72 * @den: denominator
73 * @post_div: post divider
74 * @fb_div_max: feedback divider maximum
75 * @ref_div_max: reference divider maximum
76 * @fb_div: resulting feedback divider
77 * @ref_div: resulting reference divider
78 *
79 * Calculate feedback and reference divider for a given post divider. Makes
80 * sure we stay within the limits.
81 */
82static void amdgpu_pll_get_fb_ref_div(unsigned nom, unsigned den, unsigned post_div,
83 unsigned fb_div_max, unsigned ref_div_max,
84 unsigned *fb_div, unsigned *ref_div)
85{
86 /* limit reference * post divider to a maximum */
87 ref_div_max = min(128 / post_div, ref_div_max);
88
89 /* get matching reference and feedback divider */
90 *ref_div = min(max(DIV_ROUND_CLOSEST(den, post_div), 1u), ref_div_max);
91 *fb_div = DIV_ROUND_CLOSEST(nom * *ref_div * post_div, den);
92
93 /* limit fb divider to its maximum */
94 if (*fb_div > fb_div_max) {
95 *ref_div = DIV_ROUND_CLOSEST(*ref_div * fb_div_max, *fb_div);
96 *fb_div = fb_div_max;
97 }
98}
99
100/**
101 * amdgpu_pll_compute - compute PLL paramaters
102 *
103 * @pll: information about the PLL
104 * @dot_clock_p: resulting pixel clock
105 * fb_div_p: resulting feedback divider
106 * frac_fb_div_p: fractional part of the feedback divider
107 * ref_div_p: resulting reference divider
108 * post_div_p: resulting reference divider
109 *
110 * Try to calculate the PLL parameters to generate the given frequency:
111 * dot_clock = (ref_freq * feedback_div) / (ref_div * post_div)
112 */
113void amdgpu_pll_compute(struct amdgpu_pll *pll,
114 u32 freq,
115 u32 *dot_clock_p,
116 u32 *fb_div_p,
117 u32 *frac_fb_div_p,
118 u32 *ref_div_p,
119 u32 *post_div_p)
120{
121 unsigned target_clock = pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV ?
122 freq : freq / 10;
123
124 unsigned fb_div_min, fb_div_max, fb_div;
125 unsigned post_div_min, post_div_max, post_div;
126 unsigned ref_div_min, ref_div_max, ref_div;
127 unsigned post_div_best, diff_best;
128 unsigned nom, den;
129
130 /* determine allowed feedback divider range */
131 fb_div_min = pll->min_feedback_div;
132 fb_div_max = pll->max_feedback_div;
133
134 if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
135 fb_div_min *= 10;
136 fb_div_max *= 10;
137 }
138
139 /* determine allowed ref divider range */
140 if (pll->flags & AMDGPU_PLL_USE_REF_DIV)
141 ref_div_min = pll->reference_div;
142 else
143 ref_div_min = pll->min_ref_div;
144
145 if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV &&
146 pll->flags & AMDGPU_PLL_USE_REF_DIV)
147 ref_div_max = pll->reference_div;
148 else
149 ref_div_max = pll->max_ref_div;
150
151 /* determine allowed post divider range */
152 if (pll->flags & AMDGPU_PLL_USE_POST_DIV) {
153 post_div_min = pll->post_div;
154 post_div_max = pll->post_div;
155 } else {
156 unsigned vco_min, vco_max;
157
158 if (pll->flags & AMDGPU_PLL_IS_LCD) {
159 vco_min = pll->lcd_pll_out_min;
160 vco_max = pll->lcd_pll_out_max;
161 } else {
162 vco_min = pll->pll_out_min;
163 vco_max = pll->pll_out_max;
164 }
165
166 if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
167 vco_min *= 10;
168 vco_max *= 10;
169 }
170
171 post_div_min = vco_min / target_clock;
172 if ((target_clock * post_div_min) < vco_min)
173 ++post_div_min;
174 if (post_div_min < pll->min_post_div)
175 post_div_min = pll->min_post_div;
176
177 post_div_max = vco_max / target_clock;
178 if ((target_clock * post_div_max) > vco_max)
179 --post_div_max;
180 if (post_div_max > pll->max_post_div)
181 post_div_max = pll->max_post_div;
182 }
183
184 /* represent the searched ratio as fractional number */
185 nom = target_clock;
186 den = pll->reference_freq;
187
188 /* reduce the numbers to a simpler ratio */
189 amdgpu_pll_reduce_ratio(&nom, &den, fb_div_min, post_div_min);
190
191 /* now search for a post divider */
192 if (pll->flags & AMDGPU_PLL_PREFER_MINM_OVER_MAXP)
193 post_div_best = post_div_min;
194 else
195 post_div_best = post_div_max;
196 diff_best = ~0;
197
198 for (post_div = post_div_min; post_div <= post_div_max; ++post_div) {
199 unsigned diff;
200 amdgpu_pll_get_fb_ref_div(nom, den, post_div, fb_div_max,
201 ref_div_max, &fb_div, &ref_div);
202 diff = abs(target_clock - (pll->reference_freq * fb_div) /
203 (ref_div * post_div));
204
205 if (diff < diff_best || (diff == diff_best &&
206 !(pll->flags & AMDGPU_PLL_PREFER_MINM_OVER_MAXP))) {
207
208 post_div_best = post_div;
209 diff_best = diff;
210 }
211 }
212 post_div = post_div_best;
213
214 /* get the feedback and reference divider for the optimal value */
215 amdgpu_pll_get_fb_ref_div(nom, den, post_div, fb_div_max, ref_div_max,
216 &fb_div, &ref_div);
217
218 /* reduce the numbers to a simpler ratio once more */
219 /* this also makes sure that the reference divider is large enough */
220 amdgpu_pll_reduce_ratio(&fb_div, &ref_div, fb_div_min, ref_div_min);
221
222 /* avoid high jitter with small fractional dividers */
223 if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV && (fb_div % 10)) {
224 fb_div_min = max(fb_div_min, (9 - (fb_div % 10)) * 20 + 60);
225 if (fb_div < fb_div_min) {
226 unsigned tmp = DIV_ROUND_UP(fb_div_min, fb_div);
227 fb_div *= tmp;
228 ref_div *= tmp;
229 }
230 }
231
232 /* and finally save the result */
233 if (pll->flags & AMDGPU_PLL_USE_FRAC_FB_DIV) {
234 *fb_div_p = fb_div / 10;
235 *frac_fb_div_p = fb_div % 10;
236 } else {
237 *fb_div_p = fb_div;
238 *frac_fb_div_p = 0;
239 }
240
241 *dot_clock_p = ((pll->reference_freq * *fb_div_p * 10) +
242 (pll->reference_freq * *frac_fb_div_p)) /
243 (ref_div * post_div * 10);
244 *ref_div_p = ref_div;
245 *post_div_p = post_div;
246
247 DRM_DEBUG_KMS("%d - %d, pll dividers - fb: %d.%d ref: %d, post %d\n",
248 freq, *dot_clock_p * 10, *fb_div_p, *frac_fb_div_p,
249 ref_div, post_div);
250}
251
252/**
253 * amdgpu_pll_get_use_mask - look up a mask of which pplls are in use
254 *
255 * @crtc: drm crtc
256 *
257 * Returns the mask of which PPLLs (Pixel PLLs) are in use.
258 */
259u32 amdgpu_pll_get_use_mask(struct drm_crtc *crtc)
260{
261 struct drm_device *dev = crtc->dev;
262 struct drm_crtc *test_crtc;
263 struct amdgpu_crtc *test_amdgpu_crtc;
264 u32 pll_in_use = 0;
265
266 list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
267 if (crtc == test_crtc)
268 continue;
269
270 test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
271 if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
272 pll_in_use |= (1 << test_amdgpu_crtc->pll_id);
273 }
274 return pll_in_use;
275}
276
277/**
278 * amdgpu_pll_get_shared_dp_ppll - return the PPLL used by another crtc for DP
279 *
280 * @crtc: drm crtc
281 *
282 * Returns the PPLL (Pixel PLL) used by another crtc/encoder which is
283 * also in DP mode. For DP, a single PPLL can be used for all DP
284 * crtcs/encoders.
285 */
286int amdgpu_pll_get_shared_dp_ppll(struct drm_crtc *crtc)
287{
288 struct drm_device *dev = crtc->dev;
289 struct drm_crtc *test_crtc;
290 struct amdgpu_crtc *test_amdgpu_crtc;
291
292 list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
293 if (crtc == test_crtc)
294 continue;
295 test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
296 if (test_amdgpu_crtc->encoder &&
297 ENCODER_MODE_IS_DP(amdgpu_atombios_encoder_get_encoder_mode(test_amdgpu_crtc->encoder))) {
298 /* for DP use the same PLL for all */
299 if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
300 return test_amdgpu_crtc->pll_id;
301 }
302 }
303 return ATOM_PPLL_INVALID;
304}
305
306/**
307 * amdgpu_pll_get_shared_nondp_ppll - return the PPLL used by another non-DP crtc
308 *
309 * @crtc: drm crtc
310 * @encoder: drm encoder
311 *
312 * Returns the PPLL (Pixel PLL) used by another non-DP crtc/encoder which can
313 * be shared (i.e., same clock).
314 */
315int amdgpu_pll_get_shared_nondp_ppll(struct drm_crtc *crtc)
316{
317 struct amdgpu_crtc *amdgpu_crtc = to_amdgpu_crtc(crtc);
318 struct drm_device *dev = crtc->dev;
319 struct drm_crtc *test_crtc;
320 struct amdgpu_crtc *test_amdgpu_crtc;
321 u32 adjusted_clock, test_adjusted_clock;
322
323 adjusted_clock = amdgpu_crtc->adjusted_clock;
324
325 if (adjusted_clock == 0)
326 return ATOM_PPLL_INVALID;
327
328 list_for_each_entry(test_crtc, &dev->mode_config.crtc_list, head) {
329 if (crtc == test_crtc)
330 continue;
331 test_amdgpu_crtc = to_amdgpu_crtc(test_crtc);
332 if (test_amdgpu_crtc->encoder &&
333 !ENCODER_MODE_IS_DP(amdgpu_atombios_encoder_get_encoder_mode(test_amdgpu_crtc->encoder))) {
334 /* check if we are already driving this connector with another crtc */
335 if (test_amdgpu_crtc->connector == amdgpu_crtc->connector) {
336 /* if we are, return that pll */
337 if (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID)
338 return test_amdgpu_crtc->pll_id;
339 }
340 /* for non-DP check the clock */
341 test_adjusted_clock = test_amdgpu_crtc->adjusted_clock;
342 if ((crtc->mode.clock == test_crtc->mode.clock) &&
343 (adjusted_clock == test_adjusted_clock) &&
344 (amdgpu_crtc->ss_enabled == test_amdgpu_crtc->ss_enabled) &&
345 (test_amdgpu_crtc->pll_id != ATOM_PPLL_INVALID))
346 return test_amdgpu_crtc->pll_id;
347 }
348 }
349 return ATOM_PPLL_INVALID;
350}
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