ARM: delete struct sys_timer
[linux-3.10.git] / arch / arm / mach-imx / cpufreq.c
1 /*
2  * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
3  */
4
5 /*
6  * The code contained herein is licensed under the GNU General Public
7  * License. You may obtain a copy of the GNU General Public License
8  * Version 2 or later at the following locations:
9  *
10  * http://www.opensource.org/licenses/gpl-license.html
11  * http://www.gnu.org/copyleft/gpl.html
12  */
13
14 /*
15  * A driver for the Freescale Semiconductor i.MXC CPUfreq module.
16  * The CPUFREQ driver is for controlling CPU frequency. It allows you to change
17  * the CPU clock speed on the fly.
18  */
19
20 #include <linux/module.h>
21 #include <linux/cpufreq.h>
22 #include <linux/clk.h>
23 #include <linux/err.h>
24 #include <linux/slab.h>
25
26 #include "hardware.h"
27
28 #define CLK32_FREQ      32768
29 #define NANOSECOND      (1000 * 1000 * 1000)
30
31 struct cpu_op *(*get_cpu_op)(int *op);
32
33 static int cpu_freq_khz_min;
34 static int cpu_freq_khz_max;
35
36 static struct clk *cpu_clk;
37 static struct cpufreq_frequency_table *imx_freq_table;
38
39 static int cpu_op_nr;
40 static struct cpu_op *cpu_op_tbl;
41
42 static int set_cpu_freq(int freq)
43 {
44         int ret = 0;
45         int org_cpu_rate;
46
47         org_cpu_rate = clk_get_rate(cpu_clk);
48         if (org_cpu_rate == freq)
49                 return ret;
50
51         ret = clk_set_rate(cpu_clk, freq);
52         if (ret != 0) {
53                 printk(KERN_DEBUG "cannot set CPU clock rate\n");
54                 return ret;
55         }
56
57         return ret;
58 }
59
60 static int mxc_verify_speed(struct cpufreq_policy *policy)
61 {
62         if (policy->cpu != 0)
63                 return -EINVAL;
64
65         return cpufreq_frequency_table_verify(policy, imx_freq_table);
66 }
67
68 static unsigned int mxc_get_speed(unsigned int cpu)
69 {
70         if (cpu)
71                 return 0;
72
73         return clk_get_rate(cpu_clk) / 1000;
74 }
75
76 static int mxc_set_target(struct cpufreq_policy *policy,
77                           unsigned int target_freq, unsigned int relation)
78 {
79         struct cpufreq_freqs freqs;
80         int freq_Hz;
81         int ret = 0;
82         unsigned int index;
83
84         cpufreq_frequency_table_target(policy, imx_freq_table,
85                         target_freq, relation, &index);
86         freq_Hz = imx_freq_table[index].frequency * 1000;
87
88         freqs.old = clk_get_rate(cpu_clk) / 1000;
89         freqs.new = freq_Hz / 1000;
90         freqs.cpu = 0;
91         freqs.flags = 0;
92         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
93
94         ret = set_cpu_freq(freq_Hz);
95
96         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
97
98         return ret;
99 }
100
101 static int mxc_cpufreq_init(struct cpufreq_policy *policy)
102 {
103         int ret;
104         int i;
105
106         printk(KERN_INFO "i.MXC CPU frequency driver\n");
107
108         if (policy->cpu != 0)
109                 return -EINVAL;
110
111         if (!get_cpu_op)
112                 return -EINVAL;
113
114         cpu_clk = clk_get(NULL, "cpu_clk");
115         if (IS_ERR(cpu_clk)) {
116                 printk(KERN_ERR "%s: failed to get cpu clock\n", __func__);
117                 return PTR_ERR(cpu_clk);
118         }
119
120         cpu_op_tbl = get_cpu_op(&cpu_op_nr);
121
122         cpu_freq_khz_min = cpu_op_tbl[0].cpu_rate / 1000;
123         cpu_freq_khz_max = cpu_op_tbl[0].cpu_rate / 1000;
124
125         imx_freq_table = kmalloc(
126                 sizeof(struct cpufreq_frequency_table) * (cpu_op_nr + 1),
127                         GFP_KERNEL);
128         if (!imx_freq_table) {
129                 ret = -ENOMEM;
130                 goto err1;
131         }
132
133         for (i = 0; i < cpu_op_nr; i++) {
134                 imx_freq_table[i].index = i;
135                 imx_freq_table[i].frequency = cpu_op_tbl[i].cpu_rate / 1000;
136
137                 if ((cpu_op_tbl[i].cpu_rate / 1000) < cpu_freq_khz_min)
138                         cpu_freq_khz_min = cpu_op_tbl[i].cpu_rate / 1000;
139
140                 if ((cpu_op_tbl[i].cpu_rate / 1000) > cpu_freq_khz_max)
141                         cpu_freq_khz_max = cpu_op_tbl[i].cpu_rate / 1000;
142         }
143
144         imx_freq_table[i].index = i;
145         imx_freq_table[i].frequency = CPUFREQ_TABLE_END;
146
147         policy->cur = clk_get_rate(cpu_clk) / 1000;
148         policy->min = policy->cpuinfo.min_freq = cpu_freq_khz_min;
149         policy->max = policy->cpuinfo.max_freq = cpu_freq_khz_max;
150
151         /* Manual states, that PLL stabilizes in two CLK32 periods */
152         policy->cpuinfo.transition_latency = 2 * NANOSECOND / CLK32_FREQ;
153
154         ret = cpufreq_frequency_table_cpuinfo(policy, imx_freq_table);
155
156         if (ret < 0) {
157                 printk(KERN_ERR "%s: failed to register i.MXC CPUfreq with error code %d\n",
158                        __func__, ret);
159                 goto err;
160         }
161
162         cpufreq_frequency_table_get_attr(imx_freq_table, policy->cpu);
163         return 0;
164 err:
165         kfree(imx_freq_table);
166 err1:
167         clk_put(cpu_clk);
168         return ret;
169 }
170
171 static int mxc_cpufreq_exit(struct cpufreq_policy *policy)
172 {
173         cpufreq_frequency_table_put_attr(policy->cpu);
174
175         set_cpu_freq(cpu_freq_khz_max * 1000);
176         clk_put(cpu_clk);
177         kfree(imx_freq_table);
178         return 0;
179 }
180
181 static struct cpufreq_driver mxc_driver = {
182         .flags = CPUFREQ_STICKY,
183         .verify = mxc_verify_speed,
184         .target = mxc_set_target,
185         .get = mxc_get_speed,
186         .init = mxc_cpufreq_init,
187         .exit = mxc_cpufreq_exit,
188         .name = "imx",
189 };
190
191 static int __devinit mxc_cpufreq_driver_init(void)
192 {
193         return cpufreq_register_driver(&mxc_driver);
194 }
195
196 static void mxc_cpufreq_driver_exit(void)
197 {
198         cpufreq_unregister_driver(&mxc_driver);
199 }
200
201 module_init(mxc_cpufreq_driver_init);
202 module_exit(mxc_cpufreq_driver_exit);
203
204 MODULE_AUTHOR("Freescale Semiconductor Inc. Yong Shen <yong.shen@linaro.org>");
205 MODULE_DESCRIPTION("CPUfreq driver for i.MX");
206 MODULE_LICENSE("GPL");