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