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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Utility functions for parsing Tegra CVB voltage tables4 *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) */14static 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 25static 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 38enum {39 DOWN,40 UP41};42 43static 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 55static 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 tables86 * @dev: the struct device * for which the OPP table is built87 * @tables: array of CVB tables88 * @count: size of the previously mentioned array89 * @align: parameters of the regulator step and offset90 * @process_id: process id of the HW module91 * @speedo_id: speedo id of the HW module92 * @speedo_value: speedo value of the HW module93 * @max_freq: highest safe clock rate94 *95 * On Tegra, a CVB table encodes the relationship between operating voltage96 * and safe maximal frequency for a given module (e.g. GPU or CPU). This97 * function calculates the optimal voltage-frequency operating points98 * for the given arguments and exports them via the OPP library for the99 * given @dev. Returns a pointer to the struct cvb_table that matched100 * or an ERR_PTR on failure.101 */102const struct cvb_table *103tegra_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 128void 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