1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * Utility functions for parsing Tegra CVB voltage tables |
4 | * |
5 | * Copyright (C) 2012-2019 NVIDIA Corporation. All rights reserved. |
6 | */ |
7 | #include <linux/err.h> |
8 | #include <linux/kernel.h> |
9 | #include <linux/pm_opp.h> |
10 | |
11 | #include "cvb.h" |
12 | |
13 | /* cvb_mv = ((c2 * speedo / s_scale + c1) * speedo / s_scale + c0) */ |
14 | static inline int get_cvb_voltage(int speedo, int s_scale, |
15 | const struct cvb_coefficients *cvb) |
16 | { |
17 | int mv; |
18 | |
19 | /* apply only speedo scale: output mv = cvb_mv * v_scale */ |
20 | mv = DIV_ROUND_CLOSEST(cvb->c2 * speedo, s_scale); |
21 | mv = DIV_ROUND_CLOSEST((mv + cvb->c1) * speedo, s_scale) + cvb->c0; |
22 | return mv; |
23 | } |
24 | |
25 | static int round_cvb_voltage(int mv, int v_scale, |
26 | const struct rail_alignment *align) |
27 | { |
28 | /* combined: apply voltage scale and round to cvb alignment step */ |
29 | int uv; |
30 | int step = (align->step_uv ? : 1000) * v_scale; |
31 | int offset = align->offset_uv * v_scale; |
32 | |
33 | uv = max(mv * 1000, offset) - offset; |
34 | uv = DIV_ROUND_UP(uv, step) * align->step_uv + align->offset_uv; |
35 | return uv / 1000; |
36 | } |
37 | |
38 | enum { |
39 | DOWN, |
40 | UP |
41 | }; |
42 | |
43 | static int round_voltage(int mv, const struct rail_alignment *align, int up) |
44 | { |
45 | if (align->step_uv) { |
46 | int uv; |
47 | |
48 | uv = max(mv * 1000, align->offset_uv) - align->offset_uv; |
49 | uv = (uv + (up ? align->step_uv - 1 : 0)) / align->step_uv; |
50 | return (uv * align->step_uv + align->offset_uv) / 1000; |
51 | } |
52 | return mv; |
53 | } |
54 | |
55 | static int build_opp_table(struct device *dev, const struct cvb_table *table, |
56 | struct rail_alignment *align, |
57 | int speedo_value, unsigned long max_freq) |
58 | { |
59 | int i, ret, dfll_mv, min_mv, max_mv; |
60 | |
61 | min_mv = round_voltage(mv: table->min_millivolts, align, up: UP); |
62 | max_mv = round_voltage(mv: table->max_millivolts, align, up: DOWN); |
63 | |
64 | for (i = 0; i < MAX_DVFS_FREQS; i++) { |
65 | const struct cvb_table_freq_entry *entry = &table->entries[i]; |
66 | |
67 | if (!entry->freq || (entry->freq > max_freq)) |
68 | break; |
69 | |
70 | dfll_mv = get_cvb_voltage(speedo: speedo_value, s_scale: table->speedo_scale, |
71 | cvb: &entry->coefficients); |
72 | dfll_mv = round_cvb_voltage(mv: dfll_mv, v_scale: table->voltage_scale, |
73 | align); |
74 | dfll_mv = clamp(dfll_mv, min_mv, max_mv); |
75 | |
76 | ret = dev_pm_opp_add(dev, freq: entry->freq, u_volt: dfll_mv * 1000); |
77 | if (ret) |
78 | return ret; |
79 | } |
80 | |
81 | return 0; |
82 | } |
83 | |
84 | /** |
85 | * tegra_cvb_add_opp_table - build OPP table from Tegra CVB tables |
86 | * @dev: the struct device * for which the OPP table is built |
87 | * @tables: array of CVB tables |
88 | * @count: size of the previously mentioned array |
89 | * @align: parameters of the regulator step and offset |
90 | * @process_id: process id of the HW module |
91 | * @speedo_id: speedo id of the HW module |
92 | * @speedo_value: speedo value of the HW module |
93 | * @max_freq: highest safe clock rate |
94 | * |
95 | * On Tegra, a CVB table encodes the relationship between operating voltage |
96 | * and safe maximal frequency for a given module (e.g. GPU or CPU). This |
97 | * function calculates the optimal voltage-frequency operating points |
98 | * for the given arguments and exports them via the OPP library for the |
99 | * given @dev. Returns a pointer to the struct cvb_table that matched |
100 | * or an ERR_PTR on failure. |
101 | */ |
102 | const struct cvb_table * |
103 | tegra_cvb_add_opp_table(struct device *dev, const struct cvb_table *tables, |
104 | size_t count, struct rail_alignment *align, |
105 | int process_id, int speedo_id, int speedo_value, |
106 | unsigned long max_freq) |
107 | { |
108 | size_t i; |
109 | int ret; |
110 | |
111 | for (i = 0; i < count; i++) { |
112 | const struct cvb_table *table = &tables[i]; |
113 | |
114 | if (table->speedo_id != -1 && table->speedo_id != speedo_id) |
115 | continue; |
116 | |
117 | if (table->process_id != -1 && table->process_id != process_id) |
118 | continue; |
119 | |
120 | ret = build_opp_table(dev, table, align, speedo_value, |
121 | max_freq); |
122 | return ret ? ERR_PTR(error: ret) : table; |
123 | } |
124 | |
125 | return ERR_PTR(error: -EINVAL); |
126 | } |
127 | |
128 | void tegra_cvb_remove_opp_table(struct device *dev, |
129 | const struct cvb_table *table, |
130 | unsigned long max_freq) |
131 | { |
132 | unsigned int i; |
133 | |
134 | for (i = 0; i < MAX_DVFS_FREQS; i++) { |
135 | const struct cvb_table_freq_entry *entry = &table->entries[i]; |
136 | |
137 | if (!entry->freq || (entry->freq > max_freq)) |
138 | break; |
139 | |
140 | dev_pm_opp_remove(dev, freq: entry->freq); |
141 | } |
142 | } |
143 | |