2 * arch/arm/mach-tegra/cpu-tegra.c
4 * Copyright (C) 2010 Google, Inc.
7 * Colin Cross <ccross@google.com>
8 * Based on arch/arm/plat-omap/cpu-omap.c, (C) 2005 Nokia Corporation
10 * This software is licensed under the terms of the GNU General Public
11 * License version 2, as published by the Free Software Foundation, and
12 * may be copied, distributed, and modified under those terms.
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
21 #include <linux/kernel.h>
22 #include <linux/module.h>
23 #include <linux/types.h>
24 #include <linux/sched.h>
25 #include <linux/cpufreq.h>
26 #include <linux/delay.h>
27 #include <linux/init.h>
28 #include <linux/err.h>
29 #include <linux/clk.h>
31 #include <linux/suspend.h>
33 #include <asm/system.h>
37 /* Frequency table index must be sequential starting at 0 */
38 static struct cpufreq_frequency_table freq_table[] = {
47 { 8, CPUFREQ_TABLE_END },
52 static struct clk *cpu_clk;
53 static struct clk *emc_clk;
55 static unsigned long target_cpu_speed[NUM_CPUS];
56 static DEFINE_MUTEX(tegra_cpu_lock);
57 static bool is_suspended;
59 static int tegra_verify_speed(struct cpufreq_policy *policy)
61 return cpufreq_frequency_table_verify(policy, freq_table);
64 static unsigned int tegra_getspeed(unsigned int cpu)
71 rate = clk_get_rate(cpu_clk) / 1000;
75 static int tegra_update_cpu_speed(unsigned long rate)
78 struct cpufreq_freqs freqs;
80 freqs.old = tegra_getspeed(0);
83 if (freqs.old == freqs.new)
87 * Vote on memory bus frequency based on cpu frequency
88 * This sets the minimum frequency, display or avp may request higher
91 clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
92 else if (rate >= 456000)
93 clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
95 clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
97 for_each_online_cpu(freqs.cpu)
98 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
100 #ifdef CONFIG_CPU_FREQ_DEBUG
101 printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
102 freqs.old, freqs.new);
105 ret = clk_set_rate(cpu_clk, freqs.new * 1000);
107 pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
112 for_each_online_cpu(freqs.cpu)
113 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
118 static unsigned long tegra_cpu_highest_speed(void)
120 unsigned long rate = 0;
123 for_each_online_cpu(i)
124 rate = max(rate, target_cpu_speed[i]);
128 static int tegra_target(struct cpufreq_policy *policy,
129 unsigned int target_freq,
130 unsigned int relation)
136 mutex_lock(&tegra_cpu_lock);
143 cpufreq_frequency_table_target(policy, freq_table, target_freq,
146 freq = freq_table[idx].frequency;
148 target_cpu_speed[policy->cpu] = freq;
150 ret = tegra_update_cpu_speed(tegra_cpu_highest_speed());
153 mutex_unlock(&tegra_cpu_lock);
157 static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
160 mutex_lock(&tegra_cpu_lock);
161 if (event == PM_SUSPEND_PREPARE) {
163 pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
164 freq_table[0].frequency);
165 tegra_update_cpu_speed(freq_table[0].frequency);
166 } else if (event == PM_POST_SUSPEND) {
167 is_suspended = false;
169 mutex_unlock(&tegra_cpu_lock);
174 static struct notifier_block tegra_cpu_pm_notifier = {
175 .notifier_call = tegra_pm_notify,
178 static int tegra_cpu_init(struct cpufreq_policy *policy)
180 if (policy->cpu >= NUM_CPUS)
183 cpu_clk = clk_get_sys(NULL, "cpu");
185 return PTR_ERR(cpu_clk);
187 emc_clk = clk_get_sys("cpu", "emc");
188 if (IS_ERR(emc_clk)) {
190 return PTR_ERR(emc_clk);
196 cpufreq_frequency_table_cpuinfo(policy, freq_table);
197 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
198 policy->cur = tegra_getspeed(policy->cpu);
199 target_cpu_speed[policy->cpu] = policy->cur;
201 /* FIXME: what's the actual transition time? */
202 policy->cpuinfo.transition_latency = 300 * 1000;
204 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
205 cpumask_copy(policy->related_cpus, cpu_possible_mask);
207 if (policy->cpu == 0)
208 register_pm_notifier(&tegra_cpu_pm_notifier);
213 static int tegra_cpu_exit(struct cpufreq_policy *policy)
215 cpufreq_frequency_table_cpuinfo(policy, freq_table);
216 clk_disable(emc_clk);
222 static struct freq_attr *tegra_cpufreq_attr[] = {
223 &cpufreq_freq_attr_scaling_available_freqs,
227 static struct cpufreq_driver tegra_cpufreq_driver = {
228 .verify = tegra_verify_speed,
229 .target = tegra_target,
230 .get = tegra_getspeed,
231 .init = tegra_cpu_init,
232 .exit = tegra_cpu_exit,
234 .attr = tegra_cpufreq_attr,
237 static int __init tegra_cpufreq_init(void)
239 return cpufreq_register_driver(&tegra_cpufreq_driver);
242 static void __exit tegra_cpufreq_exit(void)
244 cpufreq_unregister_driver(&tegra_cpufreq_driver);
248 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
249 MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
250 MODULE_LICENSE("GPL");
251 module_init(tegra_cpufreq_init);
252 module_exit(tegra_cpufreq_exit);