3651825e7fb9fa593f7d3fb31f157fbf1ec46a87
[linux-2.6.git] / drivers / cpufreq / omap-cpufreq.c
1 /*
2  *  CPU frequency scaling for OMAP
3  *
4  *  Copyright (C) 2005 Nokia Corporation
5  *  Written by Tony Lindgren <tony@atomide.com>
6  *
7  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
8  *
9  * Copyright (C) 2007-2011 Texas Instruments, Inc.
10  * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
11  *
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.
15  */
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>
24 #include <linux/io.h>
25 #include <linux/opp.h>
26 #include <linux/cpu.h>
27
28 #include <asm/system.h>
29 #include <asm/smp_plat.h>
30 #include <asm/cpu.h>
31
32 #include <plat/clock.h>
33 #include <plat/omap-pm.h>
34 #include <plat/common.h>
35
36 #include <mach/hardware.h>
37
38 #define VERY_HI_RATE    900000000
39
40 #ifdef CONFIG_SMP
41 struct lpj_info {
42         unsigned long   ref;
43         unsigned int    freq;
44 };
45
46 static DEFINE_PER_CPU(struct lpj_info, lpj_ref);
47 static struct lpj_info global_lpj_ref;
48 #endif
49
50 static struct cpufreq_frequency_table *freq_table;
51 static struct clk *mpu_clk;
52 static char *mpu_clk_name;
53
54 static int omap_verify_speed(struct cpufreq_policy *policy)
55 {
56         if (freq_table)
57                 return cpufreq_frequency_table_verify(policy, freq_table);
58
59         if (policy->cpu)
60                 return -EINVAL;
61
62         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
63                                      policy->cpuinfo.max_freq);
64
65         policy->min = clk_round_rate(mpu_clk, policy->min * 1000) / 1000;
66         policy->max = clk_round_rate(mpu_clk, policy->max * 1000) / 1000;
67         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
68                                      policy->cpuinfo.max_freq);
69         return 0;
70 }
71
72 static unsigned int omap_getspeed(unsigned int cpu)
73 {
74         unsigned long rate;
75
76         if (cpu >= NR_CPUS)
77                 return 0;
78
79         rate = clk_get_rate(mpu_clk) / 1000;
80         return rate;
81 }
82
83 static int omap_target(struct cpufreq_policy *policy,
84                        unsigned int target_freq,
85                        unsigned int relation)
86 {
87         int i, ret = 0;
88         struct cpufreq_freqs freqs;
89
90         /* Ensure desired rate is within allowed range.  Some govenors
91          * (ondemand) will just pass target_freq=0 to get the minimum. */
92         if (target_freq < policy->min)
93                 target_freq = policy->min;
94         if (target_freq > policy->max)
95                 target_freq = policy->max;
96
97         freqs.old = omap_getspeed(policy->cpu);
98         freqs.new = clk_round_rate(mpu_clk, target_freq * 1000) / 1000;
99         freqs.cpu = policy->cpu;
100
101         if (freqs.old == freqs.new && policy->cur == freqs.new)
102                 return ret;
103
104         /* notifiers */
105         for_each_cpu(i, policy->cpus) {
106                 freqs.cpu = i;
107                 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
108         }
109
110 #ifdef CONFIG_CPU_FREQ_DEBUG
111         pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
112 #endif
113
114         ret = clk_set_rate(mpu_clk, freqs.new * 1000);
115         freqs.new = omap_getspeed(policy->cpu);
116
117 #ifdef CONFIG_SMP
118         /*
119          * Note that loops_per_jiffy is not updated on SMP systems in
120          * cpufreq driver. So, update the per-CPU loops_per_jiffy value
121          * on frequency transition. We need to update all dependent CPUs.
122          */
123         for_each_cpu(i, policy->cpus) {
124                 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
125                 if (!lpj->freq) {
126                         lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
127                         lpj->freq = freqs.old;
128                 }
129
130                 per_cpu(cpu_data, i).loops_per_jiffy =
131                         cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
132         }
133
134         /* And don't forget to adjust the global one */
135         if (!global_lpj_ref.freq) {
136                 global_lpj_ref.ref = loops_per_jiffy;
137                 global_lpj_ref.freq = freqs.old;
138         }
139         loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
140                                         freqs.new);
141 #endif
142
143         /* notifiers */
144         for_each_cpu(i, policy->cpus) {
145                 freqs.cpu = i;
146                 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
147         }
148
149         return ret;
150 }
151
152 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
153 {
154         int result = 0;
155         struct device *mpu_dev;
156
157         mpu_clk = clk_get(NULL, mpu_clk_name);
158         if (IS_ERR(mpu_clk))
159                 return PTR_ERR(mpu_clk);
160
161         if (policy->cpu >= NR_CPUS)
162                 return -EINVAL;
163
164         policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
165         mpu_dev = omap2_get_mpuss_device();
166
167         if (!mpu_dev) {
168                 pr_warning("%s: unable to get the mpu device\n", __func__);
169                 return -EINVAL;
170         }
171         opp_init_cpufreq_table(mpu_dev, &freq_table);
172
173         if (freq_table) {
174                 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
175                 if (!result)
176                         cpufreq_frequency_table_get_attr(freq_table,
177                                                         policy->cpu);
178         } else {
179                 policy->cpuinfo.min_freq = clk_round_rate(mpu_clk, 0) / 1000;
180                 policy->cpuinfo.max_freq = clk_round_rate(mpu_clk,
181                                                         VERY_HI_RATE) / 1000;
182         }
183
184         policy->min = policy->cpuinfo.min_freq;
185         policy->max = policy->cpuinfo.max_freq;
186         policy->cur = omap_getspeed(policy->cpu);
187
188         /*
189          * On OMAP SMP configuartion, both processors share the voltage
190          * and clock. So both CPUs needs to be scaled together and hence
191          * needs software co-ordination. Use cpufreq affected_cpus
192          * interface to handle this scenario. Additional is_smp() check
193          * is to keep SMP_ON_UP build working.
194          */
195         if (is_smp()) {
196                 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
197                 cpumask_setall(policy->cpus);
198         }
199
200         /* FIXME: what's the actual transition time? */
201         policy->cpuinfo.transition_latency = 300 * 1000;
202
203         return 0;
204 }
205
206 static int omap_cpu_exit(struct cpufreq_policy *policy)
207 {
208         clk_exit_cpufreq_table(&freq_table);
209         clk_put(mpu_clk);
210         return 0;
211 }
212
213 static struct freq_attr *omap_cpufreq_attr[] = {
214         &cpufreq_freq_attr_scaling_available_freqs,
215         NULL,
216 };
217
218 static struct cpufreq_driver omap_driver = {
219         .flags          = CPUFREQ_STICKY,
220         .verify         = omap_verify_speed,
221         .target         = omap_target,
222         .get            = omap_getspeed,
223         .init           = omap_cpu_init,
224         .exit           = omap_cpu_exit,
225         .name           = "omap",
226         .attr           = omap_cpufreq_attr,
227 };
228
229 static int __init omap_cpufreq_init(void)
230 {
231         if (cpu_is_omap24xx())
232                 mpu_clk_name = "virt_prcm_set";
233         else if (cpu_is_omap34xx())
234                 mpu_clk_name = "dpll1_ck";
235         else if (cpu_is_omap44xx())
236                 mpu_clk_name = "dpll_mpu_ck";
237
238         if (!mpu_clk_name) {
239                 pr_err("%s: unsupported Silicon?\n", __func__);
240                 return -EINVAL;
241         }
242         return cpufreq_register_driver(&omap_driver);
243 }
244
245 static void __exit omap_cpufreq_exit(void)
246 {
247         cpufreq_unregister_driver(&omap_driver);
248 }
249
250 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
251 MODULE_LICENSE("GPL");
252 module_init(omap_cpufreq_init);
253 module_exit(omap_cpufreq_exit);