diff options
Diffstat (limited to 'drivers/clk/tegra/cvb.c')
| -rw-r--r-- | drivers/clk/tegra/cvb.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/clk/tegra/cvb.c b/drivers/clk/tegra/cvb.c new file mode 100644 index 000000000000..0204e0861134 --- /dev/null +++ b/drivers/clk/tegra/cvb.c @@ -0,0 +1,140 @@ +/* + * 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(const struct cvb_table *d, + int speedo_value, + unsigned long max_freq, + struct device *opp_dev) +{ + int i, ret, dfll_mv, min_mv, max_mv; + const struct cvb_table_freq_entry *table = NULL; + const struct rail_alignment *align = &d->alignment; + + min_mv = round_voltage(d->min_millivolts, align, UP); + max_mv = round_voltage(d->max_millivolts, align, DOWN); + + for (i = 0; i < MAX_DVFS_FREQS; i++) { + table = &d->cvb_table[i]; + if (!table->freq || (table->freq > max_freq)) + break; + + /* + * FIXME after clk_round_rate/clk_determine_rate prototypes + * have been updated + */ + if (table->freq & (1<<31)) + continue; + + dfll_mv = get_cvb_voltage( + speedo_value, d->speedo_scale, &table->coefficients); + dfll_mv = round_cvb_voltage(dfll_mv, d->voltage_scale, align); + dfll_mv = clamp(dfll_mv, min_mv, max_mv); + + ret = dev_pm_opp_add(opp_dev, table->freq, dfll_mv * 1000); + if (ret) + return ret; + } + + return 0; +} + +/** + * tegra_cvb_build_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_build_opp_table( + const struct cvb_table *cvb_tables, + size_t sz, int process_id, + int speedo_id, int speedo_value, + unsigned long max_rate, + struct device *opp_dev) +{ + int i, ret; + + for (i = 0; i < sz; i++) { + const struct cvb_table *d = &cvb_tables[i]; + + if (d->speedo_id != -1 && d->speedo_id != speedo_id) + continue; + if (d->process_id != -1 && d->process_id != process_id) + continue; + + ret = build_opp_table(d, speedo_value, max_rate, opp_dev); + return ret ? ERR_PTR(ret) : d; + } + + return ERR_PTR(-EINVAL); +} |