1 // SPDX-License-Identifier: MIT
2 /*
3 * Copyright © 2019 Intel Corporation
4 */
5
6 #include <linux/cpufreq.h>
7
8 #include "i915_drv.h"
9 #include "intel_gt.h"
10 #include "intel_llc.h"
11 #include "intel_sideband.h"
12
13 struct ia_constants {
14 unsigned int min_gpu_freq;
15 unsigned int max_gpu_freq;
16
17 unsigned int min_ring_freq;
18 unsigned int max_ia_freq;
19 };
20
llc_to_gt(struct intel_llc * llc)21 static struct intel_gt *llc_to_gt(struct intel_llc *llc)
22 {
23 return container_of(llc, struct intel_gt, llc);
24 }
25
cpu_max_MHz(void)26 static unsigned int cpu_max_MHz(void)
27 {
28 struct cpufreq_policy *policy;
29 unsigned int max_khz;
30
31 policy = cpufreq_cpu_get(0);
32 if (policy) {
33 max_khz = policy->cpuinfo.max_freq;
34 cpufreq_cpu_put(policy);
35 } else {
36 /*
37 * Default to measured freq if none found, PCU will ensure we
38 * don't go over
39 */
40 max_khz = tsc_khz;
41 }
42
43 return max_khz / 1000;
44 }
45
get_ia_constants(struct intel_llc * llc,struct ia_constants * consts)46 static bool get_ia_constants(struct intel_llc *llc,
47 struct ia_constants *consts)
48 {
49 struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
50 struct intel_rps *rps = &llc_to_gt(llc)->rps;
51
52 if (!HAS_LLC(i915) || IS_DGFX(i915))
53 return false;
54
55 if (rps->max_freq <= rps->min_freq)
56 return false;
57
58 consts->max_ia_freq = cpu_max_MHz();
59
60 consts->min_ring_freq =
61 intel_uncore_read(llc_to_gt(llc)->uncore, DCLK) & 0xf;
62 /* convert DDR frequency from units of 266.6MHz to bandwidth */
63 consts->min_ring_freq = mult_frac(consts->min_ring_freq, 8, 3);
64
65 consts->min_gpu_freq = rps->min_freq;
66 consts->max_gpu_freq = rps->max_freq;
67 if (GRAPHICS_VER(i915) >= 9) {
68 /* Convert GT frequency to 50 HZ units */
69 consts->min_gpu_freq /= GEN9_FREQ_SCALER;
70 consts->max_gpu_freq /= GEN9_FREQ_SCALER;
71 }
72
73 return true;
74 }
75
calc_ia_freq(struct intel_llc * llc,unsigned int gpu_freq,const struct ia_constants * consts,unsigned int * out_ia_freq,unsigned int * out_ring_freq)76 static void calc_ia_freq(struct intel_llc *llc,
77 unsigned int gpu_freq,
78 const struct ia_constants *consts,
79 unsigned int *out_ia_freq,
80 unsigned int *out_ring_freq)
81 {
82 struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
83 const int diff = consts->max_gpu_freq - gpu_freq;
84 unsigned int ia_freq = 0, ring_freq = 0;
85
86 if (GRAPHICS_VER(i915) >= 9) {
87 /*
88 * ring_freq = 2 * GT. ring_freq is in 100MHz units
89 * No floor required for ring frequency on SKL.
90 */
91 ring_freq = gpu_freq;
92 } else if (GRAPHICS_VER(i915) >= 8) {
93 /* max(2 * GT, DDR). NB: GT is 50MHz units */
94 ring_freq = max(consts->min_ring_freq, gpu_freq);
95 } else if (IS_HASWELL(i915)) {
96 ring_freq = mult_frac(gpu_freq, 5, 4);
97 ring_freq = max(consts->min_ring_freq, ring_freq);
98 /* leave ia_freq as the default, chosen by cpufreq */
99 } else {
100 const int min_freq = 15;
101 const int scale = 180;
102
103 /*
104 * On older processors, there is no separate ring
105 * clock domain, so in order to boost the bandwidth
106 * of the ring, we need to upclock the CPU (ia_freq).
107 *
108 * For GPU frequencies less than 750MHz,
109 * just use the lowest ring freq.
110 */
111 if (gpu_freq < min_freq)
112 ia_freq = 800;
113 else
114 ia_freq = consts->max_ia_freq - diff * scale / 2;
115 ia_freq = DIV_ROUND_CLOSEST(ia_freq, 100);
116 }
117
118 *out_ia_freq = ia_freq;
119 *out_ring_freq = ring_freq;
120 }
121
gen6_update_ring_freq(struct intel_llc * llc)122 static void gen6_update_ring_freq(struct intel_llc *llc)
123 {
124 struct drm_i915_private *i915 = llc_to_gt(llc)->i915;
125 struct ia_constants consts;
126 unsigned int gpu_freq;
127
128 if (!get_ia_constants(llc, &consts))
129 return;
130
131 /*
132 * For each potential GPU frequency, load a ring frequency we'd like
133 * to use for memory access. We do this by specifying the IA frequency
134 * the PCU should use as a reference to determine the ring frequency.
135 */
136 for (gpu_freq = consts.max_gpu_freq;
137 gpu_freq >= consts.min_gpu_freq;
138 gpu_freq--) {
139 unsigned int ia_freq, ring_freq;
140
141 calc_ia_freq(llc, gpu_freq, &consts, &ia_freq, &ring_freq);
142 sandybridge_pcode_write(i915,
143 GEN6_PCODE_WRITE_MIN_FREQ_TABLE,
144 ia_freq << GEN6_PCODE_FREQ_IA_RATIO_SHIFT |
145 ring_freq << GEN6_PCODE_FREQ_RING_RATIO_SHIFT |
146 gpu_freq);
147 }
148 }
149
intel_llc_enable(struct intel_llc * llc)150 void intel_llc_enable(struct intel_llc *llc)
151 {
152 gen6_update_ring_freq(llc);
153 }
154
intel_llc_disable(struct intel_llc * llc)155 void intel_llc_disable(struct intel_llc *llc)
156 {
157 /* Currently there is no HW configuration to be done to disable. */
158 }
159
160 #if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
161 #include "selftest_llc.c"
162 #endif
163