1 /*
2 * CPU frequency scaling for OMAP using OPP information
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 #include <linux/module.h>
28
29 #include <asm/system.h>
30 #include <asm/smp_plat.h>
31 #include <asm/cpu.h>
32
33 #include <plat/clock.h>
34 #include <plat/omap-pm.h>
35 #include <plat/common.h>
36 #include <plat/omap_device.h>
37
38 #include <mach/hardware.h>
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 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;
55
omap_verify_speed(struct cpufreq_policy * policy)56 static int omap_verify_speed(struct cpufreq_policy *policy)
57 {
58 if (!freq_table)
59 return -EINVAL;
60 return cpufreq_frequency_table_verify(policy, freq_table);
61 }
62
omap_getspeed(unsigned int cpu)63 static unsigned int omap_getspeed(unsigned int cpu)
64 {
65 unsigned long rate;
66
67 if (cpu >= NR_CPUS)
68 return 0;
69
70 rate = clk_get_rate(mpu_clk) / 1000;
71 return rate;
72 }
73
omap_target(struct cpufreq_policy * policy,unsigned int target_freq,unsigned int relation)74 static int omap_target(struct cpufreq_policy *policy,
75 unsigned int target_freq,
76 unsigned int relation)
77 {
78 unsigned int i;
79 int ret = 0;
80 struct cpufreq_freqs freqs;
81
82 if (!freq_table) {
83 dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
84 policy->cpu);
85 return -EINVAL;
86 }
87
88 ret = cpufreq_frequency_table_target(policy, freq_table, target_freq,
89 relation, &i);
90 if (ret) {
91 dev_dbg(mpu_dev, "%s: cpu%d: no freq match for %d(ret=%d)\n",
92 __func__, policy->cpu, target_freq, ret);
93 return ret;
94 }
95 freqs.new = freq_table[i].frequency;
96 if (!freqs.new) {
97 dev_err(mpu_dev, "%s: cpu%d: no match for freq %d\n", __func__,
98 policy->cpu, target_freq);
99 return -EINVAL;
100 }
101
102 freqs.old = omap_getspeed(policy->cpu);
103 freqs.cpu = policy->cpu;
104
105 if (freqs.old == freqs.new && policy->cur == freqs.new)
106 return ret;
107
108 /* notifiers */
109 for_each_cpu(i, policy->cpus) {
110 freqs.cpu = i;
111 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
112 }
113
114 #ifdef CONFIG_CPU_FREQ_DEBUG
115 pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
116 #endif
117
118 ret = clk_set_rate(mpu_clk, freqs.new * 1000);
119 freqs.new = omap_getspeed(policy->cpu);
120
121 #ifdef CONFIG_SMP
122 /*
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.
126 */
127 for_each_cpu(i, policy->cpus) {
128 struct lpj_info *lpj = &per_cpu(lpj_ref, i);
129 if (!lpj->freq) {
130 lpj->ref = per_cpu(cpu_data, i).loops_per_jiffy;
131 lpj->freq = freqs.old;
132 }
133
134 per_cpu(cpu_data, i).loops_per_jiffy =
135 cpufreq_scale(lpj->ref, lpj->freq, freqs.new);
136 }
137
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;
142 }
143 loops_per_jiffy = cpufreq_scale(global_lpj_ref.ref, global_lpj_ref.freq,
144 freqs.new);
145 #endif
146
147 /* notifiers */
148 for_each_cpu(i, policy->cpus) {
149 freqs.cpu = i;
150 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
151 }
152
153 return ret;
154 }
155
freq_table_free(void)156 static inline void freq_table_free(void)
157 {
158 if (atomic_dec_and_test(&freq_table_users))
159 opp_free_cpufreq_table(mpu_dev, &freq_table);
160 }
161
omap_cpu_init(struct cpufreq_policy * policy)162 static int __cpuinit omap_cpu_init(struct cpufreq_policy *policy)
163 {
164 int result = 0;
165
166 mpu_clk = clk_get(NULL, mpu_clk_name);
167 if (IS_ERR(mpu_clk))
168 return PTR_ERR(mpu_clk);
169
170 if (policy->cpu >= NR_CPUS) {
171 result = -EINVAL;
172 goto fail_ck;
173 }
174
175 policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
176
177 if (atomic_inc_return(&freq_table_users) == 1)
178 result = opp_init_cpufreq_table(mpu_dev, &freq_table);
179
180 if (result) {
181 dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
182 __func__, policy->cpu, result);
183 goto fail_ck;
184 }
185
186 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
187 if (result)
188 goto fail_table;
189
190 cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
191
192 policy->min = policy->cpuinfo.min_freq;
193 policy->max = policy->cpuinfo.max_freq;
194 policy->cur = omap_getspeed(policy->cpu);
195
196 /*
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.
202 */
203 if (is_smp()) {
204 policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
205 cpumask_setall(policy->cpus);
206 }
207
208 /* FIXME: what's the actual transition time? */
209 policy->cpuinfo.transition_latency = 300 * 1000;
210
211 return 0;
212
213 fail_table:
214 freq_table_free();
215 fail_ck:
216 clk_put(mpu_clk);
217 return result;
218 }
219
omap_cpu_exit(struct cpufreq_policy * policy)220 static int omap_cpu_exit(struct cpufreq_policy *policy)
221 {
222 freq_table_free();
223 clk_put(mpu_clk);
224 return 0;
225 }
226
227 static struct freq_attr *omap_cpufreq_attr[] = {
228 &cpufreq_freq_attr_scaling_available_freqs,
229 NULL,
230 };
231
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,
239 .name = "omap",
240 .attr = omap_cpufreq_attr,
241 };
242
omap_cpufreq_init(void)243 static int __init omap_cpufreq_init(void)
244 {
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";
251
252 if (!mpu_clk_name) {
253 pr_err("%s: unsupported Silicon?\n", __func__);
254 return -EINVAL;
255 }
256
257 mpu_dev = omap_device_get_by_hwmod_name("mpu");
258 if (!mpu_dev) {
259 pr_warning("%s: unable to get the mpu device\n", __func__);
260 return -EINVAL;
261 }
262
263 return cpufreq_register_driver(&omap_driver);
264 }
265
omap_cpufreq_exit(void)266 static void __exit omap_cpufreq_exit(void)
267 {
268 cpufreq_unregister_driver(&omap_driver);
269 }
270
271 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
272 MODULE_LICENSE("GPL");
273 module_init(omap_cpufreq_init);
274 module_exit(omap_cpufreq_exit);
275