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>
28 #include <linux/regulator/consumer.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>
40 /* OPP tolerance in percentage */
41 #define OPP_TOLERANCE 4
49 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
50 static struct lpj_info global_lpj_ref;
53 static struct cpufreq_frequency_table *freq_table;
54 static atomic_t freq_table_users = ATOMIC_INIT(0);
55 static struct clk *mpu_clk;
56 static char *mpu_clk_name;
57 static struct device *mpu_dev;
58 static struct regulator *mpu_reg;
60 static int omap_verify_speed(struct cpufreq_policy *policy)
64 return cpufreq_frequency_table_verify(policy, freq_table);
67 static unsigned int omap_getspeed(unsigned int cpu)
74 rate = clk_get_rate(mpu_clk) / 1000;
78 static int omap_target(struct cpufreq_policy *policy,
79 unsigned int target_freq,
80 unsigned int relation)
84 struct cpufreq_freqs freqs;
86 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
89 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
94 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
97 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
98 __func__, policy->cpu, target_freq, ret);
101 freqs.new = freq_table[i].frequency;
103 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
104 policy->cpu, target_freq);
108 freqs.old = omap_getspeed(policy->cpu);
109 freqs.cpu = policy->cpu;
111 if (freqs.old == freqs.new && policy->cur == freqs.new)
115 for_each_cpu(i, policy->cpus) {
117 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
120 freq = freqs.new * 1000;
123 opp = opp_find_freq_ceil(mpu_dev, &freq);
125 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
126 __func__, freqs.new);
129 volt = opp_get_voltage(opp);
130 tol = volt * OPP_TOLERANCE / 100;
131 volt_old = regulator_get_voltage(mpu_reg);
134 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
135 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
136 freqs.new / 1000, volt ? volt / 1000 : -1);
138 /* scaling up? scale voltage before frequency */
139 if (mpu_reg && (freqs.new > freqs.old)) {
140 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
142 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
144 freqs.new = freqs.old;
149 ret = clk_set_rate(mpu_clk, freqs.new * 1000);
151 /* scaling down? scale voltage after frequency */
152 if (mpu_reg && (freqs.new < freqs.old)) {
153 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
155 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
157 ret = clk_set_rate(mpu_clk, freqs.old * 1000);
158 freqs.new = freqs.old;
163 freqs.new = omap_getspeed(policy->cpu);
166 * Note that loops_per_jiffy is not updated on SMP systems in
167 * cpufreq driver. So, update the per-CPU loops_per_jiffy value
168 * on frequency transition. We need to update all dependent CPUs.
170 for_each_cpu(i, policy->cpus) {
171 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
173 lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
174 lpj->freq = freqs.old;
177 per_cpu(cpu_data, i).loops_per_jiffy =
178 cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
181 /* And don't forget to adjust the global one */
182 if (!global_lpj_ref.freq) {
183 global_lpj_ref.ref = loops_per_jiffy;
184 global_lpj_ref.freq = freqs.old;
186 loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
192 for_each_cpu(i, policy->cpus) {
194 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
200 static inline void freq_table_free(void)
202 if (atomic_dec_and_test(&freq_table_users))
203 opp_free_cpufreq_table(mpu_dev, &freq_table);
206 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
210 mpu_clk = clk_get(NULL, mpu_clk_name);
212 return PTR_ERR(mpu_clk);
214 if (policy->cpu >= NR_CPUS) {
219 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
222 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
225 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
226 __func__, policy->cpu, result);
230 atomic_inc_return(&freq_table_users);
232 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
236 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
238 policy->min = policy->cpuinfo.min_freq;
239 policy->max = policy->cpuinfo.max_freq;
240 policy->cur = omap_getspeed(policy->cpu);
243 * On OMAP SMP configuartion, both processors share the voltage
244 * and clock. So both CPUs needs to be scaled together and hence
245 * needs software co-ordination. Use cpufreq affected_cpus
246 * interface to handle this scenario. Additional is_smp() check
247 * is to keep SMP_ON_UP build working.
250 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
251 cpumask_setall(policy->cpus);
254 /* FIXME: what's the actual transition time? */
255 policy->cpuinfo.transition_latency = 300 * 1000;
266 static int omap_cpu_exit(struct cpufreq_policy *policy)
273 static struct freq_attr *omap_cpufreq_attr[] = {
274 &cpufreq_freq_attr_scaling_available_freqs,
278 static struct cpufreq_driver omap_driver = {
279 .flags = CPUFREQ_STICKY,
280 .verify = omap_verify_speed,
281 .target = omap_target,
282 .get = omap_getspeed,
283 .init = omap_cpu_init,
284 .exit = omap_cpu_exit,
286 .attr = omap_cpufreq_attr,
289 static int __init omap_cpufreq_init(void)
291 if (cpu_is_omap24xx())
292 mpu_clk_name = "virt_prcm_set";
293 else if (cpu_is_omap34xx())
294 mpu_clk_name = "dpll1_ck";
295 else if (cpu_is_omap44xx())
296 mpu_clk_name = "dpll_mpu_ck";
299 pr_err("%s: unsupported Silicon?\n", __func__);
303 mpu_dev = omap_device_get_by_hwmod_name("mpu");
305 pr_warning("%s: unable to get the mpu device\n", __func__);
309 mpu_reg = regulator_get(mpu_dev, "vcc");
310 if (IS_ERR(mpu_reg)) {
311 pr_warning("%s: unable to get MPU regulator\n", __func__);
315 * Ensure physical regulator is present.
316 * (e.g. could be dummy regulator.)
318 if (regulator_get_voltage(mpu_reg) < 0) {
319 pr_warn("%s: physical regulator not present for MPU\n",
321 regulator_put(mpu_reg);
326 return cpufreq_register_driver(&omap_driver);
329 static void __exit omap_cpufreq_exit(void)
331 cpufreq_unregister_driver(&omap_driver);
334 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
335 MODULE_LICENSE("GPL");
336 module_init(omap_cpufreq_init);
337 module_exit(omap_cpufreq_exit);