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 * @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(ret) : table; 123 } 124 125 return ERR_PTR(-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, entry->freq); 141 } 142 } 143