Loading...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 | /*
* Copyright (C) 2010 Google, Inc.
*
* Author:
* Colin Cross <ccross@google.com>
* Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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/kernel.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/err.h>
#include <linux/clk.h>
#include <linux/io.h>
static struct cpufreq_frequency_table freq_table[] = {
{ .frequency = 216000 },
{ .frequency = 312000 },
{ .frequency = 456000 },
{ .frequency = 608000 },
{ .frequency = 760000 },
{ .frequency = 816000 },
{ .frequency = 912000 },
{ .frequency = 1000000 },
{ .frequency = CPUFREQ_TABLE_END },
};
#define NUM_CPUS 2
static struct clk *cpu_clk;
static struct clk *pll_x_clk;
static struct clk *pll_p_clk;
static struct clk *emc_clk;
static bool pll_x_prepared;
static unsigned int tegra_get_intermediate(struct cpufreq_policy *policy,
unsigned int index)
{
unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
/*
* Don't switch to intermediate freq if:
* - we are already at it, i.e. policy->cur == ifreq
* - index corresponds to ifreq
*/
if ((freq_table[index].frequency == ifreq) || (policy->cur == ifreq))
return 0;
return ifreq;
}
static int tegra_target_intermediate(struct cpufreq_policy *policy,
unsigned int index)
{
int ret;
/*
* Take an extra reference to the main pll so it doesn't turn
* off when we move the cpu off of it as enabling it again while we
* switch to it from tegra_target() would take additional time.
*
* When target-freq is equal to intermediate freq we don't need to
* switch to an intermediate freq and so this routine isn't called.
* Also, we wouldn't be using pll_x anymore and must not take extra
* reference to it, as it can be disabled now to save some power.
*/
clk_prepare_enable(pll_x_clk);
ret = clk_set_parent(cpu_clk, pll_p_clk);
if (ret)
clk_disable_unprepare(pll_x_clk);
else
pll_x_prepared = true;
return ret;
}
static int tegra_target(struct cpufreq_policy *policy, unsigned int index)
{
unsigned long rate = freq_table[index].frequency;
unsigned int ifreq = clk_get_rate(pll_p_clk) / 1000;
int ret = 0;
/*
* Vote on memory bus frequency based on cpu frequency
* This sets the minimum frequency, display or avp may request higher
*/
if (rate >= 816000)
clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
else if (rate >= 456000)
clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
else
clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
/*
* target freq == pll_p, don't need to take extra reference to pll_x_clk
* as it isn't used anymore.
*/
if (rate == ifreq)
return clk_set_parent(cpu_clk, pll_p_clk);
ret = clk_set_rate(pll_x_clk, rate * 1000);
/* Restore to earlier frequency on error, i.e. pll_x */
if (ret)
pr_err("Failed to change pll_x to %lu\n", rate);
ret = clk_set_parent(cpu_clk, pll_x_clk);
/* This shouldn't fail while changing or restoring */
WARN_ON(ret);
/*
* Drop count to pll_x clock only if we switched to intermediate freq
* earlier while transitioning to a target frequency.
*/
if (pll_x_prepared) {
clk_disable_unprepare(pll_x_clk);
pll_x_prepared = false;
}
return ret;
}
static int tegra_cpu_init(struct cpufreq_policy *policy)
{
int ret;
if (policy->cpu >= NUM_CPUS)
return -EINVAL;
clk_prepare_enable(emc_clk);
clk_prepare_enable(cpu_clk);
/* FIXME: what's the actual transition time? */
ret = cpufreq_generic_init(policy, freq_table, 300 * 1000);
if (ret) {
clk_disable_unprepare(cpu_clk);
clk_disable_unprepare(emc_clk);
return ret;
}
policy->clk = cpu_clk;
policy->suspend_freq = freq_table[0].frequency;
return 0;
}
static int tegra_cpu_exit(struct cpufreq_policy *policy)
{
clk_disable_unprepare(cpu_clk);
clk_disable_unprepare(emc_clk);
return 0;
}
static struct cpufreq_driver tegra_cpufreq_driver = {
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.get_intermediate = tegra_get_intermediate,
.target_intermediate = tegra_target_intermediate,
.target_index = tegra_target,
.get = cpufreq_generic_get,
.init = tegra_cpu_init,
.exit = tegra_cpu_exit,
.name = "tegra",
.attr = cpufreq_generic_attr,
.suspend = cpufreq_generic_suspend,
};
static int __init tegra_cpufreq_init(void)
{
cpu_clk = clk_get_sys(NULL, "cclk");
if (IS_ERR(cpu_clk))
return PTR_ERR(cpu_clk);
pll_x_clk = clk_get_sys(NULL, "pll_x");
if (IS_ERR(pll_x_clk))
return PTR_ERR(pll_x_clk);
pll_p_clk = clk_get_sys(NULL, "pll_p");
if (IS_ERR(pll_p_clk))
return PTR_ERR(pll_p_clk);
emc_clk = clk_get_sys("cpu", "emc");
if (IS_ERR(emc_clk)) {
clk_put(cpu_clk);
return PTR_ERR(emc_clk);
}
return cpufreq_register_driver(&tegra_cpufreq_driver);
}
static void __exit tegra_cpufreq_exit(void)
{
cpufreq_unregister_driver(&tegra_cpufreq_driver);
clk_put(emc_clk);
clk_put(cpu_clk);
}
MODULE_AUTHOR("Colin Cross <ccross@android.com>");
MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
MODULE_LICENSE("GPL");
module_init(tegra_cpufreq_init);
module_exit(tegra_cpufreq_exit);
|