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/system.h>
31 #include <asm/smp_plat.h>
34 #include <plat/clock.h>
35 #include <plat/omap-pm.h>
36 #include <plat/common.h>
37 #include <plat/omap_device.h>
39 #include <mach/hardware.h>
41 /* OPP tolerance in percentage */
42 #define OPP_TOLERANCE 4
50 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
51 static struct lpj_info global_lpj_ref;
54 static struct cpufreq_frequency_table *freq_table;
55 static atomic_t freq_table_users = ATOMIC_INIT(0);
56 static struct clk *mpu_clk;
57 static char *mpu_clk_name;
58 static struct device *mpu_dev;
59 static struct regulator *mpu_reg;
61 static int omap_verify_speed(struct cpufreq_policy *policy)
65 return cpufreq_frequency_table_verify(policy, freq_table);
68 static unsigned int omap_getspeed(unsigned int cpu)
75 rate = clk_get_rate(mpu_clk) / 1000;
79 static int omap_target(struct cpufreq_policy *policy,
80 unsigned int target_freq,
81 unsigned int relation)
85 struct cpufreq_freqs freqs;
87 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
90 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
95 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
98 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
99 __func__, policy->cpu, target_freq, ret);
102 freqs.new = freq_table[i].frequency;
104 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
105 policy->cpu, target_freq);
109 freqs.old = omap_getspeed(policy->cpu);
110 freqs.cpu = policy->cpu;
112 if (freqs.old == freqs.new && policy->cur == freqs.new)
116 for_each_cpu(i, policy->cpus) {
118 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
121 freq = freqs.new * 1000;
124 opp = opp_find_freq_ceil(mpu_dev, &freq);
126 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
127 __func__, freqs.new);
130 volt = opp_get_voltage(opp);
131 tol = volt * OPP_TOLERANCE / 100;
132 volt_old = regulator_get_voltage(mpu_reg);
135 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
136 freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
137 freqs.new / 1000, volt ? volt / 1000 : -1);
139 /* scaling up? scale voltage before frequency */
140 if (mpu_reg && (freqs.new > freqs.old)) {
141 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
143 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
145 freqs.new = freqs.old;
150 ret = clk_set_rate(mpu_clk, freqs.new * 1000);
152 /* scaling down? scale voltage after frequency */
153 if (mpu_reg && (freqs.new < freqs.old)) {
154 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
156 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
158 ret = clk_set_rate(mpu_clk, freqs.old * 1000);
159 freqs.new = freqs.old;
164 freqs.new = omap_getspeed(policy->cpu);
167 * Note that loops_per_jiffy is not updated on SMP systems in
168 * cpufreq driver. So, update the per-CPU loops_per_jiffy value
169 * on frequency transition. We need to update all dependent CPUs.
171 for_each_cpu(i, policy->cpus) {
172 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
174 lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
175 lpj->freq = freqs.old;
178 per_cpu(cpu_data, i).loops_per_jiffy =
179 cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
182 /* And don't forget to adjust the global one */
183 if (!global_lpj_ref.freq) {
184 global_lpj_ref.ref = loops_per_jiffy;
185 global_lpj_ref.freq = freqs.old;
187 loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
193 for_each_cpu(i, policy->cpus) {
195 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
201 static inline void freq_table_free(void)
203 if (atomic_dec_and_test(&freq_table_users))
204 opp_free_cpufreq_table(mpu_dev, &freq_table);
207 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
211 mpu_clk = clk_get(NULL, mpu_clk_name);
213 return PTR_ERR(mpu_clk);
215 if (policy->cpu >= NR_CPUS) {
220 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
222 if (atomic_inc_return(&freq_table_users) == 1)
223 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
226 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
227 __func__, policy->cpu, result);
231 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
235 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
237 policy->min = policy->cpuinfo.min_freq;
238 policy->max = policy->cpuinfo.max_freq;
239 policy->cur = omap_getspeed(policy->cpu);
242 * On OMAP SMP configuartion, both processors share the voltage
243 * and clock. So both CPUs needs to be scaled together and hence
244 * needs software co-ordination. Use cpufreq affected_cpus
245 * interface to handle this scenario. Additional is_smp() check
246 * is to keep SMP_ON_UP build working.
249 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
250 cpumask_setall(policy->cpus);
253 /* FIXME: what's the actual transition time? */
254 policy->cpuinfo.transition_latency = 300 * 1000;
265 static int omap_cpu_exit(struct cpufreq_policy *policy)
272 static struct freq_attr *omap_cpufreq_attr[] = {
273 &cpufreq_freq_attr_scaling_available_freqs,
277 static struct cpufreq_driver omap_driver = {
278 .flags = CPUFREQ_STICKY,
279 .verify = omap_verify_speed,
280 .target = omap_target,
281 .get = omap_getspeed,
282 .init = omap_cpu_init,
283 .exit = omap_cpu_exit,
285 .attr = omap_cpufreq_attr,
288 static int __init omap_cpufreq_init(void)
290 if (cpu_is_omap24xx())
291 mpu_clk_name = "virt_prcm_set";
292 else if (cpu_is_omap34xx())
293 mpu_clk_name = "dpll1_ck";
294 else if (cpu_is_omap44xx())
295 mpu_clk_name = "dpll_mpu_ck";
298 pr_err("%s: unsupported Silicon?\n", __func__);
302 mpu_dev = omap_device_get_by_hwmod_name("mpu");
304 pr_warning("%s: unable to get the mpu device\n", __func__);
308 mpu_reg = regulator_get(mpu_dev, "vcc");
309 if (IS_ERR(mpu_reg)) {
310 pr_warning("%s: unable to get MPU regulator\n", __func__);
314 * Ensure physical regulator is present.
315 * (e.g. could be dummy regulator.)
317 if (regulator_get_voltage(mpu_reg) < 0) {
318 pr_warn("%s: physical regulator not present for MPU\n",
320 regulator_put(mpu_reg);
325 return cpufreq_register_driver(&omap_driver);
328 static void __exit omap_cpufreq_exit(void)
330 cpufreq_unregister_driver(&omap_driver);
333 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
334 MODULE_LICENSE("GPL");
335 module_init(omap_cpufreq_init);
336 module_exit(omap_cpufreq_exit);