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(table->min_millivolts, align, UP); 62 max_mv = round_voltage(table->max_millivolts, align, 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_value, table->speedo_scale, 71 &entry->coefficients); 72 dfll_mv = round_cvb_voltage(dfll_mv, table->voltage_scale, 73 align); 74 dfll_mv = clamp(dfll_mv, min_mv, max_mv); 75 76 ret = dev_pm_opp_add(dev, entry->freq, 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 * @process_id: process id of the HW module 90 * @speedo_id: speedo id of the HW module 91 * @speedo_value: speedo value of the HW module 92 * @max_freq: highest safe clock rate 93 * 94 * On Tegra, a CVB table encodes the relationship between operating voltage 95 * and safe maximal frequency for a given module (e.g. GPU or CPU). This 96 * function calculates the optimal voltage-frequency operating points 97 * for the given arguments and exports them via the OPP library for the 98 * given @dev. Returns a pointer to the struct cvb_table that matched 99 * or an ERR_PTR on failure. 100 */ 101 const struct cvb_table * 102 tegra_cvb_add_opp_table(struct device *dev, const struct cvb_table *tables, 103 size_t count, struct rail_alignment *align, 104 int process_id, int speedo_id, int speedo_value, 105 unsigned long max_freq) 106 { 107 size_t i; 108 int ret; 109 110 for (i = 0; i < count; i++) { 111 const struct cvb_table *table = &tables[i]; 112 113 if (table->speedo_id != -1 && table->speedo_id != speedo_id) 114 continue; 115 116 if (table->process_id != -1 && table->process_id != process_id) 117 continue; 118 119 ret = build_opp_table(dev, table, align, speedo_value, 120 max_freq); 121 return ret ? ERR_PTR(ret) : table; 122 } 123 124 return ERR_PTR(-EINVAL); 125 } 126 127 void tegra_cvb_remove_opp_table(struct device *dev, 128 const struct cvb_table *table, 129 unsigned long max_freq) 130 { 131 unsigned int i; 132 133 for (i = 0; i < MAX_DVFS_FREQS; i++) { 134 const struct cvb_table_freq_entry *entry = &table->entries[i]; 135 136 if (!entry->freq || (entry->freq > max_freq)) 137 break; 138 139 dev_pm_opp_remove(dev, entry->freq); 140 } 141 } 142