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 64 static int build_opp_table(struct device *dev, const struct cvb_table *table, 65 int speedo_value, unsigned long max_freq) 66 { 67 const struct rail_alignment *align = &table->alignment; 68 int i, ret, dfll_mv, min_mv, max_mv; 69 70 min_mv = round_voltage(table->min_millivolts, align, UP); 71 max_mv = round_voltage(table->max_millivolts, align, DOWN); 72 73 for (i = 0; i < MAX_DVFS_FREQS; i++) { 74 const struct cvb_table_freq_entry *entry = &table->entries[i]; 75 76 if (!entry->freq || (entry->freq > max_freq)) 77 break; 78 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); 83 dfll_mv = clamp(dfll_mv, min_mv, max_mv); 84 85 ret = dev_pm_opp_add(dev, entry->freq, dfll_mv * 1000); 86 if (ret) 87 return ret; 88 } 89 90 return 0; 91 } 92 93 /** 94 * tegra_cvb_add_opp_table - build OPP table from Tegra CVB tables 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 */ 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) 114 { 115 size_t i; 116 int ret; 117 118 for (i = 0; i < count; i++) { 119 const struct cvb_table *table = &tables[i]; 120 121 if (table->speedo_id != -1 && table->speedo_id != speedo_id) 122 continue; 123 124 if (table->process_id != -1 && table->process_id != process_id) 125 continue; 126 127 ret = build_opp_table(dev, table, speedo_value, max_freq); 128 return ret ? ERR_PTR(ret) : table; 129 } 130 131 return ERR_PTR(-EINVAL); 132 } 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 } 149