diff options
Diffstat (limited to 'drivers/clk/tegra/cvb.c')
| -rw-r--r-- | drivers/clk/tegra/cvb.c | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/drivers/clk/tegra/cvb.c b/drivers/clk/tegra/cvb.c new file mode 100644 index 000000000..da9e8e7b5 --- /dev/null +++ b/drivers/clk/tegra/cvb.c @@ -0,0 +1,148 @@ +/* + * 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 + * @dev: the struct device * for which the OPP table is built + * @tables: array of CVB tables + * @count: 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_freq: highest safe clock rate + * + * 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 @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); + } +} |