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
43 static struct cpufreq_frequency_table *freq_table;
44 static atomic_t freq_table_users = ATOMIC_INIT(0);
45 static struct clk *mpu_clk;
46 static char *mpu_clk_name;
47 static struct device *mpu_dev;
48 static struct regulator *mpu_reg;
50 static int omap_verify_speed(struct cpufreq_policy *policy)
54 return cpufreq_frequency_table_verify(policy, freq_table);
57 static unsigned int omap_getspeed(unsigned int cpu)
64 rate = clk_get_rate(mpu_clk) / 1000;
68 static int omap_target(struct cpufreq_policy *policy,
69 unsigned int target_freq,
70 unsigned int relation)
74 struct cpufreq_freqs freqs;
76 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
79 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
84 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
87 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
88 __func__, policy->cpu, target_freq, ret);
91 freqs.new = freq_table[i].frequency;
93 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
94 policy->cpu, target_freq);
98 freqs.old = omap_getspeed(policy->cpu);
99 freqs.cpu = policy->cpu;
101 if (freqs.old == freqs.new && policy->cur == freqs.new)
105 for_each_cpu(i, policy->cpus) {
107 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
110 freq = freqs.new * 1000;
113 opp = opp_find_freq_ceil(mpu_dev, &freq);
115 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
116 __func__, freqs.new);
119 volt = opp_get_voltage(opp);
120 tol = volt * OPP_TOLERANCE / 100;
121 volt_old = regulator_get_voltage(mpu_reg);
124 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
125 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
126 freqs.new / 1000, volt ? volt / 1000 : -1);
128 /* scaling up? scale voltage before frequency */
129 if (mpu_reg && (freqs.new > freqs.old)) {
130 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
132 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
134 freqs.new = freqs.old;
139 ret = clk_set_rate(mpu_clk, freqs.new * 1000);
141 /* scaling down? scale voltage after frequency */
142 if (mpu_reg && (freqs.new < freqs.old)) {
143 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
145 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
147 ret = clk_set_rate(mpu_clk, freqs.old * 1000);
148 freqs.new = freqs.old;
153 freqs.new = omap_getspeed(policy->cpu);
157 for_each_cpu(i, policy->cpus) {
159 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
165 static inline void freq_table_free(void)
167 if (atomic_dec_and_test(&freq_table_users))
168 opp_free_cpufreq_table(mpu_dev, &freq_table);
171 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
175 mpu_clk = clk_get(NULL, mpu_clk_name);
177 return PTR_ERR(mpu_clk);
179 if (policy->cpu >= NR_CPUS) {
184 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
187 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
190 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
191 __func__, policy->cpu, result);
195 atomic_inc_return(&freq_table_users);
197 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
201 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
203 policy->min = policy->cpuinfo.min_freq;
204 policy->max = policy->cpuinfo.max_freq;
205 policy->cur = omap_getspeed(policy->cpu);
208 * On OMAP SMP configuartion, both processors share the voltage
209 * and clock. So both CPUs needs to be scaled together and hence
210 * needs software co-ordination. Use cpufreq affected_cpus
211 * interface to handle this scenario. Additional is_smp() check
212 * is to keep SMP_ON_UP build working.
215 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
216 cpumask_setall(policy->cpus);
219 /* FIXME: what's the actual transition time? */
220 policy->cpuinfo.transition_latency = 300 * 1000;
231 static int omap_cpu_exit(struct cpufreq_policy *policy)
238 static struct freq_attr *omap_cpufreq_attr[] = {
239 &cpufreq_freq_attr_scaling_available_freqs,
243 static struct cpufreq_driver omap_driver = {
244 .flags = CPUFREQ_STICKY,
245 .verify = omap_verify_speed,
246 .target = omap_target,
247 .get = omap_getspeed,
248 .init = omap_cpu_init,
249 .exit = omap_cpu_exit,
251 .attr = omap_cpufreq_attr,
254 static int __init omap_cpufreq_init(void)
256 if (cpu_is_omap24xx())
257 mpu_clk_name = "virt_prcm_set";
258 else if (cpu_is_omap34xx())
259 mpu_clk_name = "dpll1_ck";
260 else if (cpu_is_omap44xx())
261 mpu_clk_name = "dpll_mpu_ck";
264 pr_err("%s: unsupported Silicon?\n", __func__);
268 mpu_dev = omap_device_get_by_hwmod_name("mpu");
269 if (IS_ERR(mpu_dev)) {
270 pr_warning("%s: unable to get the mpu device\n", __func__);
271 return PTR_ERR(mpu_dev);
274 mpu_reg = regulator_get(mpu_dev, "vcc");
275 if (IS_ERR(mpu_reg)) {
276 pr_warning("%s: unable to get MPU regulator\n", __func__);
280 * Ensure physical regulator is present.
281 * (e.g. could be dummy regulator.)
283 if (regulator_get_voltage(mpu_reg) < 0) {
284 pr_warn("%s: physical regulator not present for MPU\n",
286 regulator_put(mpu_reg);
291 return cpufreq_register_driver(&omap_driver);
294 static void __exit omap_cpufreq_exit(void)
296 cpufreq_unregister_driver(&omap_driver);
299 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
300 MODULE_LICENSE("GPL");
301 module_init(omap_cpufreq_init);
302 module_exit(omap_cpufreq_exit);