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>
36 /* Frequency table index must be sequential starting at 0 */
37 static struct cpufreq_frequency_table freq_table[] = {
46 { 8, CPUFREQ_TABLE_END },
51 static struct clk *cpu_clk;
52 static struct clk *emc_clk;
54 static unsigned long target_cpu_speed[NUM_CPUS];
55 static DEFINE_MUTEX(tegra_cpu_lock);
56 static bool is_suspended;
58 static int tegra_verify_speed(struct cpufreq_policy *policy)
60 return cpufreq_frequency_table_verify(policy, freq_table);
63 static unsigned int tegra_getspeed(unsigned int cpu)
70 rate = clk_get_rate(cpu_clk) / 1000;
74 static int tegra_update_cpu_speed(unsigned long rate)
77 struct cpufreq_freqs freqs;
79 freqs.old = tegra_getspeed(0);
82 if (freqs.old == freqs.new)
86 * Vote on memory bus frequency based on cpu frequency
87 * This sets the minimum frequency, display or avp may request higher
90 clk_set_rate(emc_clk, 600000000); /* cpu 816 MHz, emc max */
91 else if (rate >= 456000)
92 clk_set_rate(emc_clk, 300000000); /* cpu 456 MHz, emc 150Mhz */
94 clk_set_rate(emc_clk, 100000000); /* emc 50Mhz */
96 for_each_online_cpu(freqs.cpu)
97 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
99 #ifdef CONFIG_CPU_FREQ_DEBUG
100 printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
101 freqs.old, freqs.new);
104 ret = clk_set_rate(cpu_clk, freqs.new * 1000);
106 pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
111 for_each_online_cpu(freqs.cpu)
112 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
117 static unsigned long tegra_cpu_highest_speed(void)
119 unsigned long rate = 0;
122 for_each_online_cpu(i)
123 rate = max(rate, target_cpu_speed[i]);
127 static int tegra_target(struct cpufreq_policy *policy,
128 unsigned int target_freq,
129 unsigned int relation)
135 mutex_lock(&tegra_cpu_lock);
142 cpufreq_frequency_table_target(policy, freq_table, target_freq,
145 freq = freq_table[idx].frequency;
147 target_cpu_speed[policy->cpu] = freq;
149 ret = tegra_update_cpu_speed(tegra_cpu_highest_speed());
152 mutex_unlock(&tegra_cpu_lock);
156 static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
159 mutex_lock(&tegra_cpu_lock);
160 if (event == PM_SUSPEND_PREPARE) {
162 pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
163 freq_table[0].frequency);
164 tegra_update_cpu_speed(freq_table[0].frequency);
165 } else if (event == PM_POST_SUSPEND) {
166 is_suspended = false;
168 mutex_unlock(&tegra_cpu_lock);
173 static struct notifier_block tegra_cpu_pm_notifier = {
174 .notifier_call = tegra_pm_notify,
177 static int tegra_cpu_init(struct cpufreq_policy *policy)
179 if (policy->cpu >= NUM_CPUS)
182 cpu_clk = clk_get_sys(NULL, "cpu");
184 return PTR_ERR(cpu_clk);
186 emc_clk = clk_get_sys("cpu", "emc");
187 if (IS_ERR(emc_clk)) {
189 return PTR_ERR(emc_clk);
195 cpufreq_frequency_table_cpuinfo(policy, freq_table);
196 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
197 policy->cur = tegra_getspeed(policy->cpu);
198 target_cpu_speed[policy->cpu] = policy->cur;
200 /* FIXME: what's the actual transition time? */
201 policy->cpuinfo.transition_latency = 300 * 1000;
203 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
204 cpumask_copy(policy->related_cpus, cpu_possible_mask);
206 if (policy->cpu == 0)
207 register_pm_notifier(&tegra_cpu_pm_notifier);
212 static int tegra_cpu_exit(struct cpufreq_policy *policy)
214 cpufreq_frequency_table_cpuinfo(policy, freq_table);
215 clk_disable(emc_clk);
221 static struct freq_attr *tegra_cpufreq_attr[] = {
222 &cpufreq_freq_attr_scaling_available_freqs,
226 static struct cpufreq_driver tegra_cpufreq_driver = {
227 .verify = tegra_verify_speed,
228 .target = tegra_target,
229 .get = tegra_getspeed,
230 .init = tegra_cpu_init,
231 .exit = tegra_cpu_exit,
233 .attr = tegra_cpufreq_attr,
236 static int __init tegra_cpufreq_init(void)
238 return cpufreq_register_driver(&tegra_cpufreq_driver);
241 static void __exit tegra_cpufreq_exit(void)
243 cpufreq_unregister_driver(&tegra_cpufreq_driver);
247 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
248 MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
249 MODULE_LICENSE("GPL");
250 module_init(tegra_cpufreq_init);
251 module_exit(tegra_cpufreq_exit);