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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/pm_opp.h>
26#include <linux/cpu.h>
27#include <linux/module.h>
28#include <linux/platform_device.h>
29#include <linux/regulator/consumer.h>
30
31#include <asm/smp_plat.h>
32#include <asm/cpu.h>
33
34
35#define OPP_TOLERANCE 4
36
37static struct cpufreq_frequency_table *freq_table;
38static atomic_t freq_table_users = ATOMIC_INIT(0);
39static struct device *mpu_dev;
40static struct regulator *mpu_reg;
41
42static int omap_target(struct cpufreq_policy *policy, unsigned int index)
43{
44 int r, ret;
45 struct dev_pm_opp *opp;
46 unsigned long freq, volt = 0, volt_old = 0, tol = 0;
47 unsigned int old_freq, new_freq;
48
49 old_freq = policy->cur;
50 new_freq = freq_table[index].frequency;
51
52 freq = new_freq * 1000;
53 ret = clk_round_rate(policy->clk, freq);
54 if (IS_ERR_VALUE(ret)) {
55 dev_warn(mpu_dev,
56 "CPUfreq: Cannot find matching frequency for %lu\n",
57 freq);
58 return ret;
59 }
60 freq = ret;
61
62 if (mpu_reg) {
63 rcu_read_lock();
64 opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
65 if (IS_ERR(opp)) {
66 rcu_read_unlock();
67 dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
68 __func__, new_freq);
69 return -EINVAL;
70 }
71 volt = dev_pm_opp_get_voltage(opp);
72 rcu_read_unlock();
73 tol = volt * OPP_TOLERANCE / 100;
74 volt_old = regulator_get_voltage(mpu_reg);
75 }
76
77 dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
78 old_freq / 1000, volt_old ? volt_old / 1000 : -1,
79 new_freq / 1000, volt ? volt / 1000 : -1);
80
81
82 if (mpu_reg && (new_freq > old_freq)) {
83 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
84 if (r < 0) {
85 dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
86 __func__);
87 return r;
88 }
89 }
90
91 ret = clk_set_rate(policy->clk, new_freq * 1000);
92
93
94 if (mpu_reg && (new_freq < old_freq)) {
95 r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
96 if (r < 0) {
97 dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
98 __func__);
99 clk_set_rate(policy->clk, old_freq * 1000);
100 return r;
101 }
102 }
103
104 return ret;
105}
106
107static inline void freq_table_free(void)
108{
109 if (atomic_dec_and_test(&freq_table_users))
110 dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
111}
112
113static int omap_cpu_init(struct cpufreq_policy *policy)
114{
115 int result;
116
117 policy->clk = clk_get(NULL, "cpufreq_ck");
118 if (IS_ERR(policy->clk))
119 return PTR_ERR(policy->clk);
120
121 if (!freq_table) {
122 result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
123 if (result) {
124 dev_err(mpu_dev,
125 "%s: cpu%d: failed creating freq table[%d]\n",
126 __func__, policy->cpu, result);
127 goto fail;
128 }
129 }
130
131 atomic_inc_return(&freq_table_users);
132
133
134 result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
135 if (!result)
136 return 0;
137
138 freq_table_free();
139fail:
140 clk_put(policy->clk);
141 return result;
142}
143
144static int omap_cpu_exit(struct cpufreq_policy *policy)
145{
146 freq_table_free();
147 clk_put(policy->clk);
148 return 0;
149}
150
151static struct cpufreq_driver omap_driver = {
152 .flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
153 .verify = cpufreq_generic_frequency_table_verify,
154 .target_index = omap_target,
155 .get = cpufreq_generic_get,
156 .init = omap_cpu_init,
157 .exit = omap_cpu_exit,
158 .name = "omap",
159 .attr = cpufreq_generic_attr,
160};
161
162static int omap_cpufreq_probe(struct platform_device *pdev)
163{
164 mpu_dev = get_cpu_device(0);
165 if (!mpu_dev) {
166 pr_warning("%s: unable to get the mpu device\n", __func__);
167 return -EINVAL;
168 }
169
170 mpu_reg = regulator_get(mpu_dev, "vcc");
171 if (IS_ERR(mpu_reg)) {
172 pr_warning("%s: unable to get MPU regulator\n", __func__);
173 mpu_reg = NULL;
174 } else {
175
176
177
178
179 if (regulator_get_voltage(mpu_reg) < 0) {
180 pr_warn("%s: physical regulator not present for MPU\n",
181 __func__);
182 regulator_put(mpu_reg);
183 mpu_reg = NULL;
184 }
185 }
186
187 return cpufreq_register_driver(&omap_driver);
188}
189
190static int omap_cpufreq_remove(struct platform_device *pdev)
191{
192 return cpufreq_unregister_driver(&omap_driver);
193}
194
195static struct platform_driver omap_cpufreq_platdrv = {
196 .driver = {
197 .name = "omap-cpufreq",
198 .owner = THIS_MODULE,
199 },
200 .probe = omap_cpufreq_probe,
201 .remove = omap_cpufreq_remove,
202};
203module_platform_driver(omap_cpufreq_platdrv);
204
205MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
206MODULE_LICENSE("GPL");
207
