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