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7c1a70e9 MP |
1 | /* |
2 | * CPU frequency scaling for u8500 | |
3 | * Inspired by linux/arch/arm/mach-davinci/cpufreq.c | |
4 | * | |
5 | * Copyright (C) STMicroelectronics 2009 | |
6 | * Copyright (C) ST-Ericsson SA 2010 | |
7 | * | |
8 | * License Terms: GNU General Public License v2 | |
9 | * | |
10 | * Author: Sundar Iyer <sundar.iyer@stericsson.com> | |
11 | * Author: Martin Persson <martin.persson@stericsson.com> | |
12 | * Author: Jonas Aaberg <jonas.aberg@stericsson.com> | |
13 | * | |
14 | */ | |
15 | ||
16 | #include <linux/platform_device.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/cpufreq.h> | |
19 | #include <linux/delay.h> | |
650c2a21 | 20 | #include <linux/mfd/db8500-prcmu.h> |
7c1a70e9 MP |
21 | |
22 | #include <mach/hardware.h> | |
7c1a70e9 MP |
23 | |
24 | #define DRIVER_NAME "cpufreq-u8500" | |
25 | #define CPUFREQ_NAME "u8500" | |
26 | ||
27 | static struct device *dev; | |
28 | ||
29 | static struct cpufreq_frequency_table freq_table[] = { | |
30 | [0] = { | |
31 | .index = 0, | |
32 | .frequency = 200000, | |
33 | }, | |
34 | [1] = { | |
35 | .index = 1, | |
36 | .frequency = 300000, | |
37 | }, | |
38 | [2] = { | |
39 | .index = 2, | |
40 | .frequency = 600000, | |
41 | }, | |
42 | [3] = { | |
43 | /* Used for CPU_OPP_MAX, if available */ | |
44 | .index = 3, | |
45 | .frequency = CPUFREQ_TABLE_END, | |
46 | }, | |
47 | [4] = { | |
48 | .index = 4, | |
49 | .frequency = CPUFREQ_TABLE_END, | |
50 | }, | |
51 | }; | |
52 | ||
53 | static enum prcmu_cpu_opp index2opp[] = { | |
54 | CPU_OPP_EXT_CLK, | |
55 | CPU_OPP_50, | |
56 | CPU_OPP_100, | |
57 | CPU_OPP_MAX | |
58 | }; | |
59 | ||
60 | static int u8500_cpufreq_verify_speed(struct cpufreq_policy *policy) | |
61 | { | |
62 | return cpufreq_frequency_table_verify(policy, freq_table); | |
63 | } | |
64 | ||
65 | static int u8500_cpufreq_target(struct cpufreq_policy *policy, | |
66 | unsigned int target_freq, | |
67 | unsigned int relation) | |
68 | { | |
69 | struct cpufreq_freqs freqs; | |
70 | unsigned int index; | |
71 | int ret = 0; | |
72 | ||
73 | /* | |
74 | * Ensure desired rate is within allowed range. Some govenors | |
75 | * (ondemand) will just pass target_freq=0 to get the minimum. | |
76 | */ | |
77 | if (target_freq < policy->cpuinfo.min_freq) | |
78 | target_freq = policy->cpuinfo.min_freq; | |
79 | if (target_freq > policy->cpuinfo.max_freq) | |
80 | target_freq = policy->cpuinfo.max_freq; | |
81 | ||
82 | ret = cpufreq_frequency_table_target(policy, freq_table, | |
83 | target_freq, relation, &index); | |
84 | if (ret < 0) { | |
85 | dev_err(dev, "Could not look up next frequency\n"); | |
86 | return ret; | |
87 | } | |
88 | ||
89 | freqs.old = policy->cur; | |
90 | freqs.new = freq_table[index].frequency; | |
91 | freqs.cpu = policy->cpu; | |
92 | ||
93 | if (freqs.old == freqs.new) { | |
94 | dev_dbg(dev, "Current and target frequencies are equal\n"); | |
95 | return 0; | |
96 | } | |
97 | ||
98 | dev_dbg(dev, "transition: %u --> %u\n", freqs.old, freqs.new); | |
99 | cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); | |
100 | ||
101 | ret = prcmu_set_cpu_opp(index2opp[index]); | |
102 | if (ret < 0) { | |
103 | dev_err(dev, "Failed to set OPP level\n"); | |
104 | return ret; | |
105 | } | |
106 | ||
107 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); | |
108 | ||
109 | return ret; | |
110 | } | |
111 | ||
112 | static unsigned int u8500_cpufreq_getspeed(unsigned int cpu) | |
113 | { | |
114 | int i; | |
115 | ||
116 | for (i = 0; prcmu_get_cpu_opp() != index2opp[i]; i++) | |
117 | ; | |
118 | return freq_table[i].frequency; | |
119 | } | |
120 | ||
121 | static int __cpuinit u8500_cpu_init(struct cpufreq_policy *policy) | |
122 | { | |
123 | int res; | |
124 | ||
125 | BUILD_BUG_ON(ARRAY_SIZE(index2opp) + 1 != ARRAY_SIZE(freq_table)); | |
126 | ||
127 | if (cpu_is_u8500v2()) { | |
128 | freq_table[1].frequency = 400000; | |
129 | freq_table[2].frequency = 800000; | |
130 | if (prcmu_has_arm_maxopp()) | |
131 | freq_table[3].frequency = 1000000; | |
132 | } | |
133 | ||
134 | /* get policy fields based on the table */ | |
135 | res = cpufreq_frequency_table_cpuinfo(policy, freq_table); | |
136 | if (!res) | |
137 | cpufreq_frequency_table_get_attr(freq_table, policy->cpu); | |
138 | else { | |
139 | dev_err(dev, "u8500-cpufreq : Failed to read policy table\n"); | |
140 | return res; | |
141 | } | |
142 | ||
143 | policy->min = policy->cpuinfo.min_freq; | |
144 | policy->max = policy->cpuinfo.max_freq; | |
145 | policy->cur = u8500_cpufreq_getspeed(policy->cpu); | |
146 | policy->governor = CPUFREQ_DEFAULT_GOVERNOR; | |
147 | ||
148 | /* | |
149 | * FIXME : Need to take time measurement across the target() | |
150 | * function with no/some/all drivers in the notification | |
151 | * list. | |
152 | */ | |
153 | policy->cpuinfo.transition_latency = 200 * 1000; /* in ns */ | |
154 | ||
155 | /* policy sharing between dual CPUs */ | |
156 | cpumask_copy(policy->cpus, &cpu_present_map); | |
157 | ||
158 | policy->shared_type = CPUFREQ_SHARED_TYPE_ALL; | |
159 | ||
160 | return res; | |
161 | } | |
162 | ||
163 | static struct freq_attr *u8500_cpufreq_attr[] = { | |
164 | &cpufreq_freq_attr_scaling_available_freqs, | |
165 | NULL, | |
166 | }; | |
167 | static int u8500_cpu_exit(struct cpufreq_policy *policy) | |
168 | { | |
169 | cpufreq_frequency_table_put_attr(policy->cpu); | |
170 | return 0; | |
171 | } | |
172 | ||
173 | static struct cpufreq_driver u8500_driver = { | |
174 | .owner = THIS_MODULE, | |
175 | .flags = CPUFREQ_STICKY, | |
176 | .verify = u8500_cpufreq_verify_speed, | |
177 | .target = u8500_cpufreq_target, | |
178 | .get = u8500_cpufreq_getspeed, | |
179 | .init = u8500_cpu_init, | |
180 | .exit = u8500_cpu_exit, | |
181 | .name = CPUFREQ_NAME, | |
182 | .attr = u8500_cpufreq_attr, | |
183 | }; | |
184 | ||
185 | static int __init u8500_cpufreq_probe(struct platform_device *pdev) | |
186 | { | |
187 | dev = &pdev->dev; | |
188 | return cpufreq_register_driver(&u8500_driver); | |
189 | } | |
190 | ||
191 | static int __exit u8500_cpufreq_remove(struct platform_device *pdev) | |
192 | { | |
193 | return cpufreq_unregister_driver(&u8500_driver); | |
194 | } | |
195 | ||
196 | static struct platform_driver u8500_cpufreq_driver = { | |
197 | .driver = { | |
198 | .name = DRIVER_NAME, | |
199 | .owner = THIS_MODULE, | |
200 | }, | |
201 | .remove = __exit_p(u8500_cpufreq_remove), | |
202 | }; | |
203 | ||
204 | static int __init u8500_cpufreq_init(void) | |
205 | { | |
206 | return platform_driver_probe(&u8500_cpufreq_driver, | |
207 | &u8500_cpufreq_probe); | |
208 | } | |
209 | ||
210 | device_initcall(u8500_cpufreq_init); |