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6601b803 SN |
1 | /* |
2 | * CPU frequency scaling for DaVinci | |
3 | * | |
4 | * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/ | |
5 | * | |
6 | * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows: | |
7 | * | |
8 | * Copyright (C) 2005 Nokia Corporation | |
9 | * Written by Tony Lindgren <tony@atomide.com> | |
10 | * | |
11 | * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King | |
12 | * | |
13 | * Copyright (C) 2007-2008 Texas Instruments, Inc. | |
14 | * Updated to support OMAP3 | |
15 | * Rajendra Nayak <rnayak@ti.com> | |
16 | * | |
17 | * This program is free software; you can redistribute it and/or modify | |
18 | * it under the terms of the GNU General Public License version 2 as | |
19 | * published by the Free Software Foundation. | |
20 | */ | |
21 | #include <linux/types.h> | |
22 | #include <linux/cpufreq.h> | |
23 | #include <linux/init.h> | |
24 | #include <linux/err.h> | |
25 | #include <linux/clk.h> | |
26 | #include <linux/platform_device.h> | |
dc28094b | 27 | #include <linux/export.h> |
6601b803 SN |
28 | |
29 | #include <mach/hardware.h> | |
30 | #include <mach/cpufreq.h> | |
31 | #include <mach/common.h> | |
32 | ||
6601b803 SN |
33 | struct davinci_cpufreq { |
34 | struct device *dev; | |
35 | struct clk *armclk; | |
30a2c5d2 SN |
36 | struct clk *asyncclk; |
37 | unsigned long asyncrate; | |
6601b803 SN |
38 | }; |
39 | static struct davinci_cpufreq cpufreq; | |
40 | ||
41 | static int davinci_verify_speed(struct cpufreq_policy *policy) | |
42 | { | |
43 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
44 | struct cpufreq_frequency_table *freq_table = pdata->freq_table; | |
45 | struct clk *armclk = cpufreq.armclk; | |
46 | ||
47 | if (freq_table) | |
48 | return cpufreq_frequency_table_verify(policy, freq_table); | |
49 | ||
50 | if (policy->cpu) | |
51 | return -EINVAL; | |
52 | ||
53 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
54 | policy->cpuinfo.max_freq); | |
55 | ||
56 | policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000; | |
57 | policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000; | |
58 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
59 | policy->cpuinfo.max_freq); | |
60 | return 0; | |
61 | } | |
62 | ||
63 | static unsigned int davinci_getspeed(unsigned int cpu) | |
64 | { | |
65 | if (cpu) | |
66 | return 0; | |
67 | ||
68 | return clk_get_rate(cpufreq.armclk) / 1000; | |
69 | } | |
70 | ||
71 | static int davinci_target(struct cpufreq_policy *policy, | |
72 | unsigned int target_freq, unsigned int relation) | |
73 | { | |
74 | int ret = 0; | |
75 | unsigned int idx; | |
76 | struct cpufreq_freqs freqs; | |
77 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
78 | struct clk *armclk = cpufreq.armclk; | |
79 | ||
6601b803 SN |
80 | freqs.old = davinci_getspeed(0); |
81 | freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000; | |
6601b803 SN |
82 | |
83 | if (freqs.old == freqs.new) | |
84 | return ret; | |
85 | ||
d870df68 | 86 | dev_dbg(cpufreq.dev, "transition: %u --> %u\n", freqs.old, freqs.new); |
6601b803 SN |
87 | |
88 | ret = cpufreq_frequency_table_target(policy, pdata->freq_table, | |
89 | freqs.new, relation, &idx); | |
90 | if (ret) | |
91 | return -EINVAL; | |
92 | ||
b43a7ffb | 93 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
6601b803 SN |
94 | |
95 | /* if moving to higher frequency, up the voltage beforehand */ | |
fca97b33 SN |
96 | if (pdata->set_voltage && freqs.new > freqs.old) { |
97 | ret = pdata->set_voltage(idx); | |
98 | if (ret) | |
99 | goto out; | |
100 | } | |
6601b803 SN |
101 | |
102 | ret = clk_set_rate(armclk, idx); | |
fca97b33 SN |
103 | if (ret) |
104 | goto out; | |
6601b803 | 105 | |
30a2c5d2 SN |
106 | if (cpufreq.asyncclk) { |
107 | ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); | |
108 | if (ret) | |
109 | goto out; | |
110 | } | |
111 | ||
6601b803 SN |
112 | /* if moving to lower freq, lower the voltage after lowering freq */ |
113 | if (pdata->set_voltage && freqs.new < freqs.old) | |
114 | pdata->set_voltage(idx); | |
115 | ||
fca97b33 | 116 | out: |
f20b97d9 VK |
117 | if (ret) |
118 | freqs.new = freqs.old; | |
119 | ||
b43a7ffb | 120 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
6601b803 SN |
121 | |
122 | return ret; | |
123 | } | |
124 | ||
079db590 | 125 | static int davinci_cpu_init(struct cpufreq_policy *policy) |
6601b803 SN |
126 | { |
127 | int result = 0; | |
128 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
129 | struct cpufreq_frequency_table *freq_table = pdata->freq_table; | |
130 | ||
131 | if (policy->cpu != 0) | |
132 | return -EINVAL; | |
133 | ||
13d5e27a SN |
134 | /* Finish platform specific initialization */ |
135 | if (pdata->init) { | |
136 | result = pdata->init(); | |
137 | if (result) | |
138 | return result; | |
139 | } | |
140 | ||
eb2f50ff VK |
141 | policy->cur = davinci_getspeed(0); |
142 | ||
143 | result = cpufreq_frequency_table_cpuinfo(policy, freq_table); | |
144 | if (result) { | |
145 | pr_err("%s: cpufreq_frequency_table_cpuinfo() failed", | |
146 | __func__); | |
147 | return result; | |
6601b803 SN |
148 | } |
149 | ||
eb2f50ff | 150 | cpufreq_frequency_table_get_attr(freq_table, policy->cpu); |
6601b803 SN |
151 | |
152 | /* | |
153 | * Time measurement across the target() function yields ~1500-1800us | |
154 | * time taken with no drivers on notification list. | |
25985edc | 155 | * Setting the latency to 2000 us to accommodate addition of drivers |
6601b803 SN |
156 | * to pre/post change notification list. |
157 | */ | |
158 | policy->cpuinfo.transition_latency = 2000 * 1000; | |
159 | return 0; | |
160 | } | |
161 | ||
162 | static int davinci_cpu_exit(struct cpufreq_policy *policy) | |
163 | { | |
164 | cpufreq_frequency_table_put_attr(policy->cpu); | |
165 | return 0; | |
166 | } | |
167 | ||
168 | static struct freq_attr *davinci_cpufreq_attr[] = { | |
169 | &cpufreq_freq_attr_scaling_available_freqs, | |
170 | NULL, | |
171 | }; | |
172 | ||
173 | static struct cpufreq_driver davinci_driver = { | |
174 | .flags = CPUFREQ_STICKY, | |
175 | .verify = davinci_verify_speed, | |
176 | .target = davinci_target, | |
177 | .get = davinci_getspeed, | |
178 | .init = davinci_cpu_init, | |
179 | .exit = davinci_cpu_exit, | |
180 | .name = "davinci", | |
181 | .attr = davinci_cpufreq_attr, | |
182 | }; | |
183 | ||
184 | static int __init davinci_cpufreq_probe(struct platform_device *pdev) | |
185 | { | |
186 | struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; | |
30a2c5d2 | 187 | struct clk *asyncclk; |
6601b803 SN |
188 | |
189 | if (!pdata) | |
190 | return -EINVAL; | |
191 | if (!pdata->freq_table) | |
192 | return -EINVAL; | |
193 | ||
194 | cpufreq.dev = &pdev->dev; | |
195 | ||
196 | cpufreq.armclk = clk_get(NULL, "arm"); | |
197 | if (IS_ERR(cpufreq.armclk)) { | |
198 | dev_err(cpufreq.dev, "Unable to get ARM clock\n"); | |
199 | return PTR_ERR(cpufreq.armclk); | |
200 | } | |
201 | ||
30a2c5d2 SN |
202 | asyncclk = clk_get(cpufreq.dev, "async"); |
203 | if (!IS_ERR(asyncclk)) { | |
204 | cpufreq.asyncclk = asyncclk; | |
205 | cpufreq.asyncrate = clk_get_rate(asyncclk); | |
206 | } | |
207 | ||
6601b803 SN |
208 | return cpufreq_register_driver(&davinci_driver); |
209 | } | |
210 | ||
211 | static int __exit davinci_cpufreq_remove(struct platform_device *pdev) | |
212 | { | |
213 | clk_put(cpufreq.armclk); | |
214 | ||
30a2c5d2 SN |
215 | if (cpufreq.asyncclk) |
216 | clk_put(cpufreq.asyncclk); | |
217 | ||
6601b803 SN |
218 | return cpufreq_unregister_driver(&davinci_driver); |
219 | } | |
220 | ||
221 | static struct platform_driver davinci_cpufreq_driver = { | |
222 | .driver = { | |
223 | .name = "cpufreq-davinci", | |
224 | .owner = THIS_MODULE, | |
225 | }, | |
226 | .remove = __exit_p(davinci_cpufreq_remove), | |
227 | }; | |
228 | ||
3aa3e840 | 229 | int __init davinci_cpufreq_init(void) |
6601b803 SN |
230 | { |
231 | return platform_driver_probe(&davinci_cpufreq_driver, | |
232 | davinci_cpufreq_probe); | |
233 | } | |
6601b803 | 234 |