2 * CPU frequency scaling for OMAP using OPP information
4 * Copyright (C) 2005 Nokia Corporation
5 * Written by Tony Lindgren <tony@atomide.com>
7 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
9 * Copyright (C) 2007-2011 Texas Instruments, Inc.
10 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/cpufreq.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/clk.h>
25 #include <linux/opp.h>
26 #include <linux/cpu.h>
27 #include <linux/module.h>
29 #include <asm/system.h>
30 #include <asm/smp_plat.h>
33 #include <plat/clock.h>
34 #include <plat/omap-pm.h>
35 #include <plat/common.h>
36 #include <plat/omap_device.h>
38 #include <mach/hardware.h>
46 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
47 static struct lpj_info global_lpj_ref;
50 static struct cpufreq_frequency_table *freq_table;
51 static atomic_t freq_table_users = ATOMIC_INIT(0);
52 static struct clk *mpu_clk;
53 static char *mpu_clk_name;
54 static struct device *mpu_dev;
56 static int omap_verify_speed(struct cpufreq_policy *policy)
60 return cpufreq_frequency_table_verify(policy, freq_table);
63 static unsigned int omap_getspeed(unsigned int cpu)
70 rate = clk_get_rate(mpu_clk) / 1000;
74 static int omap_target(struct cpufreq_policy *policy,
75 unsigned int target_freq,
76 unsigned int relation)
80 struct cpufreq_freqs freqs;
83 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
88 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
91 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
92 __func__, policy->cpu, target_freq, ret);
95 freqs.new = freq_table[i].frequency;
97 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
98 policy->cpu, target_freq);
102 freqs.old = omap_getspeed(policy->cpu);
103 freqs.cpu = policy->cpu;
105 if (freqs.old == freqs.new && policy->cur == freqs.new)
109 for_each_cpu(i, policy->cpus) {
111 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
114 #ifdef CONFIG_CPU_FREQ_DEBUG
115 pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
118 ret = clk_set_rate(mpu_clk, freqs.new * 1000);
119 freqs.new = omap_getspeed(policy->cpu);
123 * Note that loops_per_jiffy is not updated on SMP systems in
124 * cpufreq driver. So, update the per-CPU loops_per_jiffy value
125 * on frequency transition. We need to update all dependent CPUs.
127 for_each_cpu(i, policy->cpus) {
128 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
130 lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
131 lpj->freq = freqs.old;
134 per_cpu(cpu_data, i).loops_per_jiffy =
135 cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
138 /* And don't forget to adjust the global one */
139 if (!global_lpj_ref.freq) {
140 global_lpj_ref.ref = loops_per_jiffy;
141 global_lpj_ref.freq = freqs.old;
143 loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
148 for_each_cpu(i, policy->cpus) {
150 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
156 static inline void freq_table_free(void)
158 if (atomic_dec_and_test(&freq_table_users))
159 opp_free_cpufreq_table(mpu_dev, &freq_table);
162 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
166 mpu_clk = clk_get(NULL, mpu_clk_name);
168 return PTR_ERR(mpu_clk);
170 if (policy->cpu >= NR_CPUS) {
175 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
177 if (atomic_inc_return(&freq_table_users) == 1)
178 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
181 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
182 __func__, policy->cpu, result);
186 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
190 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
192 policy->min = policy->cpuinfo.min_freq;
193 policy->max = policy->cpuinfo.max_freq;
194 policy->cur = omap_getspeed(policy->cpu);
197 * On OMAP SMP configuartion, both processors share the voltage
198 * and clock. So both CPUs needs to be scaled together and hence
199 * needs software co-ordination. Use cpufreq affected_cpus
200 * interface to handle this scenario. Additional is_smp() check
201 * is to keep SMP_ON_UP build working.
204 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
205 cpumask_setall(policy->cpus);
208 /* FIXME: what's the actual transition time? */
209 policy->cpuinfo.transition_latency = 300 * 1000;
220 static int omap_cpu_exit(struct cpufreq_policy *policy)
227 static struct freq_attr *omap_cpufreq_attr[] = {
228 &cpufreq_freq_attr_scaling_available_freqs,
232 static struct cpufreq_driver omap_driver = {
233 .flags = CPUFREQ_STICKY,
234 .verify = omap_verify_speed,
235 .target = omap_target,
236 .get = omap_getspeed,
237 .init = omap_cpu_init,
238 .exit = omap_cpu_exit,
240 .attr = omap_cpufreq_attr,
243 static int __init omap_cpufreq_init(void)
245 if (cpu_is_omap24xx())
246 mpu_clk_name = "virt_prcm_set";
247 else if (cpu_is_omap34xx())
248 mpu_clk_name = "dpll1_ck";
249 else if (cpu_is_omap44xx())
250 mpu_clk_name = "dpll_mpu_ck";
253 pr_err("%s: unsupported Silicon?\n", __func__);
257 mpu_dev = omap_device_get_by_hwmod_name("mpu");
259 pr_warning("%s: unable to get the mpu device\n", __func__);
263 return cpufreq_register_driver(&omap_driver);
266 static void __exit omap_cpufreq_exit(void)
268 cpufreq_unregister_driver(&omap_driver);
271 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
272 MODULE_LICENSE("GPL");
273 module_init(omap_cpufreq_init);
274 module_exit(omap_cpufreq_exit);