134 lines
3.9 KiB
C
134 lines
3.9 KiB
C
/*
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* Utility functions for parsing Tegra CVB voltage tables
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*
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* Copyright (C) 2012-2014 NVIDIA Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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*/
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/pm_opp.h>
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#include "cvb.h"
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/* cvb_mv = ((c2 * speedo / s_scale + c1) * speedo / s_scale + c0) */
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static inline int get_cvb_voltage(int speedo, int s_scale,
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const struct cvb_coefficients *cvb)
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{
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int mv;
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/* apply only speedo scale: output mv = cvb_mv * v_scale */
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mv = DIV_ROUND_CLOSEST(cvb->c2 * speedo, s_scale);
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mv = DIV_ROUND_CLOSEST((mv + cvb->c1) * speedo, s_scale) + cvb->c0;
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return mv;
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}
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static int round_cvb_voltage(int mv, int v_scale,
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const struct rail_alignment *align)
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{
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/* combined: apply voltage scale and round to cvb alignment step */
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int uv;
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int step = (align->step_uv ? : 1000) * v_scale;
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int offset = align->offset_uv * v_scale;
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uv = max(mv * 1000, offset) - offset;
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uv = DIV_ROUND_UP(uv, step) * align->step_uv + align->offset_uv;
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return uv / 1000;
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}
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enum {
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DOWN,
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UP
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};
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static int round_voltage(int mv, const struct rail_alignment *align, int up)
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{
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if (align->step_uv) {
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int uv;
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uv = max(mv * 1000, align->offset_uv) - align->offset_uv;
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uv = (uv + (up ? align->step_uv - 1 : 0)) / align->step_uv;
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return (uv * align->step_uv + align->offset_uv) / 1000;
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}
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return mv;
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}
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static int build_opp_table(const struct cvb_table *d,
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int speedo_value,
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unsigned long max_freq,
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struct device *opp_dev)
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{
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int i, ret, dfll_mv, min_mv, max_mv;
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const struct cvb_table_freq_entry *table = NULL;
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const struct rail_alignment *align = &d->alignment;
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min_mv = round_voltage(d->min_millivolts, align, UP);
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max_mv = round_voltage(d->max_millivolts, align, DOWN);
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for (i = 0; i < MAX_DVFS_FREQS; i++) {
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table = &d->cvb_table[i];
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if (!table->freq || (table->freq > max_freq))
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break;
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dfll_mv = get_cvb_voltage(
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speedo_value, d->speedo_scale, &table->coefficients);
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dfll_mv = round_cvb_voltage(dfll_mv, d->voltage_scale, align);
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dfll_mv = clamp(dfll_mv, min_mv, max_mv);
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ret = dev_pm_opp_add(opp_dev, table->freq, dfll_mv * 1000);
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if (ret)
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return ret;
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}
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return 0;
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}
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/**
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* tegra_cvb_build_opp_table - build OPP table from Tegra CVB tables
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* @cvb_tables: array of CVB tables
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* @sz: size of the previously mentioned array
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* @process_id: process id of the HW module
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* @speedo_id: speedo id of the HW module
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* @speedo_value: speedo value of the HW module
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* @max_rate: highest safe clock rate
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* @opp_dev: the struct device * for which the OPP table is built
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*
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* On Tegra, a CVB table encodes the relationship between operating voltage
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* and safe maximal frequency for a given module (e.g. GPU or CPU). This
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* function calculates the optimal voltage-frequency operating points
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* for the given arguments and exports them via the OPP library for the
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* given @opp_dev. Returns a pointer to the struct cvb_table that matched
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* or an ERR_PTR on failure.
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*/
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const struct cvb_table *tegra_cvb_build_opp_table(
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const struct cvb_table *cvb_tables,
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size_t sz, int process_id,
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int speedo_id, int speedo_value,
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unsigned long max_rate,
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struct device *opp_dev)
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{
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int i, ret;
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for (i = 0; i < sz; i++) {
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const struct cvb_table *d = &cvb_tables[i];
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if (d->speedo_id != -1 && d->speedo_id != speedo_id)
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continue;
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if (d->process_id != -1 && d->process_id != process_id)
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continue;
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ret = build_opp_table(d, speedo_value, max_rate, opp_dev);
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return ret ? ERR_PTR(ret) : d;
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}
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return ERR_PTR(-EINVAL);
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}
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