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fa63aa3d TT |
1 | /* |
2 | * Utility functions for parsing Tegra CVB voltage tables | |
3 | * | |
4 | * Copyright (C) 2012-2014 NVIDIA Corporation. All rights reserved. | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License version 2 as | |
8 | * published by the Free Software Foundation. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
11 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
12 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
13 | * more details. | |
14 | * | |
15 | */ | |
16 | #include <linux/err.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/pm_opp.h> | |
19 | ||
20 | #include "cvb.h" | |
21 | ||
22 | /* cvb_mv = ((c2 * speedo / s_scale + c1) * speedo / s_scale + c0) */ | |
23 | static inline int get_cvb_voltage(int speedo, int s_scale, | |
24 | const struct cvb_coefficients *cvb) | |
25 | { | |
26 | int mv; | |
27 | ||
28 | /* apply only speedo scale: output mv = cvb_mv * v_scale */ | |
29 | mv = DIV_ROUND_CLOSEST(cvb->c2 * speedo, s_scale); | |
30 | mv = DIV_ROUND_CLOSEST((mv + cvb->c1) * speedo, s_scale) + cvb->c0; | |
31 | return mv; | |
32 | } | |
33 | ||
34 | static int round_cvb_voltage(int mv, int v_scale, | |
35 | const struct rail_alignment *align) | |
36 | { | |
37 | /* combined: apply voltage scale and round to cvb alignment step */ | |
38 | int uv; | |
39 | int step = (align->step_uv ? : 1000) * v_scale; | |
40 | int offset = align->offset_uv * v_scale; | |
41 | ||
42 | uv = max(mv * 1000, offset) - offset; | |
43 | uv = DIV_ROUND_UP(uv, step) * align->step_uv + align->offset_uv; | |
44 | return uv / 1000; | |
45 | } | |
46 | ||
47 | enum { | |
48 | DOWN, | |
49 | UP | |
50 | }; | |
51 | ||
52 | static int round_voltage(int mv, const struct rail_alignment *align, int up) | |
53 | { | |
54 | if (align->step_uv) { | |
55 | int uv; | |
56 | ||
57 | uv = max(mv * 1000, align->offset_uv) - align->offset_uv; | |
58 | uv = (uv + (up ? align->step_uv - 1 : 0)) / align->step_uv; | |
59 | return (uv * align->step_uv + align->offset_uv) / 1000; | |
60 | } | |
61 | return mv; | |
62 | } | |
63 | ||
e8f6a68c TR |
64 | static int build_opp_table(struct device *dev, const struct cvb_table *table, |
65 | int speedo_value, unsigned long max_freq) | |
fa63aa3d | 66 | { |
e8f6a68c | 67 | const struct rail_alignment *align = &table->alignment; |
fa63aa3d | 68 | int i, ret, dfll_mv, min_mv, max_mv; |
fa63aa3d | 69 | |
e8f6a68c TR |
70 | min_mv = round_voltage(table->min_millivolts, align, UP); |
71 | max_mv = round_voltage(table->max_millivolts, align, DOWN); | |
fa63aa3d TT |
72 | |
73 | for (i = 0; i < MAX_DVFS_FREQS; i++) { | |
e8f6a68c TR |
74 | const struct cvb_table_freq_entry *entry = &table->entries[i]; |
75 | ||
76 | if (!entry->freq || (entry->freq > max_freq)) | |
fa63aa3d TT |
77 | break; |
78 | ||
e8f6a68c TR |
79 | dfll_mv = get_cvb_voltage(speedo_value, table->speedo_scale, |
80 | &entry->coefficients); | |
81 | dfll_mv = round_cvb_voltage(dfll_mv, table->voltage_scale, | |
82 | align); | |
fa63aa3d TT |
83 | dfll_mv = clamp(dfll_mv, min_mv, max_mv); |
84 | ||
e8f6a68c | 85 | ret = dev_pm_opp_add(dev, entry->freq, dfll_mv * 1000); |
fa63aa3d TT |
86 | if (ret) |
87 | return ret; | |
88 | } | |
89 | ||
90 | return 0; | |
91 | } | |
92 | ||
93 | /** | |
e8f6a68c | 94 | * tegra_cvb_add_opp_table - build OPP table from Tegra CVB tables |
fa63aa3d TT |
95 | * @cvb_tables: array of CVB tables |
96 | * @sz: size of the previously mentioned array | |
97 | * @process_id: process id of the HW module | |
98 | * @speedo_id: speedo id of the HW module | |
99 | * @speedo_value: speedo value of the HW module | |
100 | * @max_rate: highest safe clock rate | |
101 | * @opp_dev: the struct device * for which the OPP table is built | |
102 | * | |
103 | * On Tegra, a CVB table encodes the relationship between operating voltage | |
104 | * and safe maximal frequency for a given module (e.g. GPU or CPU). This | |
105 | * function calculates the optimal voltage-frequency operating points | |
106 | * for the given arguments and exports them via the OPP library for the | |
107 | * given @opp_dev. Returns a pointer to the struct cvb_table that matched | |
108 | * or an ERR_PTR on failure. | |
109 | */ | |
e8f6a68c TR |
110 | const struct cvb_table * |
111 | tegra_cvb_add_opp_table(struct device *dev, const struct cvb_table *tables, | |
112 | size_t count, int process_id, int speedo_id, | |
113 | int speedo_value, unsigned long max_freq) | |
fa63aa3d | 114 | { |
e8f6a68c TR |
115 | size_t i; |
116 | int ret; | |
fa63aa3d | 117 | |
e8f6a68c TR |
118 | for (i = 0; i < count; i++) { |
119 | const struct cvb_table *table = &tables[i]; | |
fa63aa3d | 120 | |
e8f6a68c | 121 | if (table->speedo_id != -1 && table->speedo_id != speedo_id) |
fa63aa3d | 122 | continue; |
e8f6a68c TR |
123 | |
124 | if (table->process_id != -1 && table->process_id != process_id) | |
fa63aa3d TT |
125 | continue; |
126 | ||
e8f6a68c TR |
127 | ret = build_opp_table(dev, table, speedo_value, max_freq); |
128 | return ret ? ERR_PTR(ret) : table; | |
fa63aa3d TT |
129 | } |
130 | ||
131 | return ERR_PTR(-EINVAL); | |
132 | } | |
f7c42d98 TR |
133 | |
134 | void tegra_cvb_remove_opp_table(struct device *dev, | |
135 | const struct cvb_table *table, | |
136 | unsigned long max_freq) | |
137 | { | |
138 | unsigned int i; | |
139 | ||
140 | for (i = 0; i < MAX_DVFS_FREQS; i++) { | |
141 | const struct cvb_table_freq_entry *entry = &table->entries[i]; | |
142 | ||
143 | if (!entry->freq || (entry->freq > max_freq)) | |
144 | break; | |
145 | ||
146 | dev_pm_opp_remove(dev, entry->freq); | |
147 | } | |
148 | } |