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/smp_twd.h>
34 #include <asm/system.h>
36 #include <mach/hardware.h>
39 /* Frequency table index must be sequential starting at 0 */
40 static struct cpufreq_frequency_table freq_table[] = {
49 { 8, CPUFREQ_TABLE_END },
54 static struct clk *cpu_clk;
56 static unsigned long target_cpu_speed[NUM_CPUS];
57 static DEFINE_MUTEX(tegra_cpu_lock);
58 static bool is_suspended;
60 int tegra_verify_speed(struct cpufreq_policy *policy)
62 return cpufreq_frequency_table_verify(policy, freq_table);
65 unsigned int tegra_getspeed(unsigned int cpu)
72 rate = clk_get_rate(cpu_clk) / 1000;
76 #ifdef CONFIG_HAVE_ARM_TWD
77 static void tegra_cpufreq_rescale_twd_other_cpu(void *data) {
78 unsigned long new_rate = *(unsigned long *)data;
79 twd_recalc_prescaler(new_rate);
82 static void tegra_cpufreq_rescale_twds(unsigned long new_rate)
84 twd_recalc_prescaler(new_rate);
85 smp_call_function(tegra_cpufreq_rescale_twd_other_cpu, &new_rate, 1);
88 static inline void tegra_cpufreq_rescale_twds(unsigned long new_rate)
93 static int tegra_update_cpu_speed(unsigned long rate)
96 struct cpufreq_freqs freqs;
98 freqs.old = tegra_getspeed(0);
101 if (freqs.old == freqs.new)
104 for_each_online_cpu(freqs.cpu)
105 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
107 if (freqs.new > freqs.old)
108 tegra_cpufreq_rescale_twds(freqs.new * 1000);
110 #ifdef CONFIG_CPU_FREQ_DEBUG
111 printk(KERN_DEBUG "cpufreq-tegra: transition: %u --> %u\n",
112 freqs.old, freqs.new);
115 ret = clk_set_rate(cpu_clk, freqs.new * 1000);
117 pr_err("cpu-tegra: Failed to set cpu frequency to %d kHz\n",
122 if (freqs.new < freqs.old)
123 tegra_cpufreq_rescale_twds(freqs.new * 1000);
125 for_each_online_cpu(freqs.cpu)
126 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
131 static unsigned long tegra_cpu_highest_speed(void) {
132 unsigned long rate = 0;
135 for_each_online_cpu(i)
136 rate = max(rate, target_cpu_speed[i]);
140 static int tegra_target(struct cpufreq_policy *policy,
141 unsigned int target_freq,
142 unsigned int relation)
148 mutex_lock(&tegra_cpu_lock);
155 cpufreq_frequency_table_target(policy, freq_table, target_freq,
158 freq = freq_table[idx].frequency;
160 target_cpu_speed[policy->cpu] = freq;
162 ret = tegra_update_cpu_speed(tegra_cpu_highest_speed());
165 mutex_unlock(&tegra_cpu_lock);
169 static int tegra_pm_notify(struct notifier_block *nb, unsigned long event,
172 mutex_lock(&tegra_cpu_lock);
173 if (event == PM_SUSPEND_PREPARE) {
175 pr_info("Tegra cpufreq suspend: setting frequency to %d kHz\n",
176 freq_table[0].frequency);
177 tegra_update_cpu_speed(freq_table[0].frequency);
178 } else if (event == PM_POST_SUSPEND) {
179 is_suspended = false;
181 mutex_unlock(&tegra_cpu_lock);
186 static struct notifier_block tegra_cpu_pm_notifier = {
187 .notifier_call = tegra_pm_notify,
190 static int tegra_cpu_init(struct cpufreq_policy *policy)
192 if (policy->cpu >= NUM_CPUS)
195 cpu_clk = clk_get_sys(NULL, "cpu");
197 return PTR_ERR(cpu_clk);
199 cpufreq_frequency_table_cpuinfo(policy, freq_table);
200 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
201 policy->cur = tegra_getspeed(policy->cpu);
202 target_cpu_speed[policy->cpu] = policy->cur;
204 /* FIXME: what's the actual transition time? */
205 policy->cpuinfo.transition_latency = 300 * 1000;
207 policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
208 cpumask_copy(policy->related_cpus, cpu_possible_mask);
210 if (policy->cpu == 0)
211 register_pm_notifier(&tegra_cpu_pm_notifier);
216 static int tegra_cpu_exit(struct cpufreq_policy *policy)
218 cpufreq_frequency_table_cpuinfo(policy, freq_table);
223 static struct freq_attr *tegra_cpufreq_attr[] = {
224 &cpufreq_freq_attr_scaling_available_freqs,
228 static struct cpufreq_driver tegra_cpufreq_driver = {
229 .verify = tegra_verify_speed,
230 .target = tegra_target,
231 .get = tegra_getspeed,
232 .init = tegra_cpu_init,
233 .exit = tegra_cpu_exit,
235 .attr = tegra_cpufreq_attr,
238 static int __init tegra_cpufreq_init(void)
240 return cpufreq_register_driver(&tegra_cpufreq_driver);
243 static void __exit tegra_cpufreq_exit(void)
245 cpufreq_unregister_driver(&tegra_cpufreq_driver);
249 MODULE_AUTHOR("Colin Cross <ccross@android.com>");
250 MODULE_DESCRIPTION("cpufreq driver for Nvidia Tegra2");
251 MODULE_LICENSE("GPL");
252 module_init(tegra_cpufreq_init);
253 module_exit(tegra_cpufreq_exit);