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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 | ||
33 | #include "clock.h" | |
34 | ||
35 | struct davinci_cpufreq { | |
36 | struct device *dev; | |
37 | struct clk *armclk; | |
30a2c5d2 SN |
38 | struct clk *asyncclk; |
39 | unsigned long asyncrate; | |
6601b803 SN |
40 | }; |
41 | static struct davinci_cpufreq cpufreq; | |
42 | ||
43 | static int davinci_verify_speed(struct cpufreq_policy *policy) | |
44 | { | |
45 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
46 | struct cpufreq_frequency_table *freq_table = pdata->freq_table; | |
47 | struct clk *armclk = cpufreq.armclk; | |
48 | ||
49 | if (freq_table) | |
50 | return cpufreq_frequency_table_verify(policy, freq_table); | |
51 | ||
52 | if (policy->cpu) | |
53 | return -EINVAL; | |
54 | ||
55 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
56 | policy->cpuinfo.max_freq); | |
57 | ||
58 | policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000; | |
59 | policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000; | |
60 | cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, | |
61 | policy->cpuinfo.max_freq); | |
62 | return 0; | |
63 | } | |
64 | ||
65 | static unsigned int davinci_getspeed(unsigned int cpu) | |
66 | { | |
67 | if (cpu) | |
68 | return 0; | |
69 | ||
70 | return clk_get_rate(cpufreq.armclk) / 1000; | |
71 | } | |
72 | ||
73 | static int davinci_target(struct cpufreq_policy *policy, | |
74 | unsigned int target_freq, unsigned int relation) | |
75 | { | |
76 | int ret = 0; | |
77 | unsigned int idx; | |
78 | struct cpufreq_freqs freqs; | |
79 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
80 | struct clk *armclk = cpufreq.armclk; | |
81 | ||
82 | /* | |
83 | * Ensure desired rate is within allowed range. Some govenors | |
84 | * (ondemand) will just pass target_freq=0 to get the minimum. | |
85 | */ | |
86 | if (target_freq < policy->cpuinfo.min_freq) | |
87 | target_freq = policy->cpuinfo.min_freq; | |
88 | if (target_freq > policy->cpuinfo.max_freq) | |
89 | target_freq = policy->cpuinfo.max_freq; | |
90 | ||
91 | freqs.old = davinci_getspeed(0); | |
92 | freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000; | |
6601b803 SN |
93 | |
94 | if (freqs.old == freqs.new) | |
95 | return ret; | |
96 | ||
d870df68 | 97 | dev_dbg(cpufreq.dev, "transition: %u --> %u\n", freqs.old, freqs.new); |
6601b803 SN |
98 | |
99 | ret = cpufreq_frequency_table_target(policy, pdata->freq_table, | |
100 | freqs.new, relation, &idx); | |
101 | if (ret) | |
102 | return -EINVAL; | |
103 | ||
b43a7ffb | 104 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE); |
6601b803 SN |
105 | |
106 | /* if moving to higher frequency, up the voltage beforehand */ | |
fca97b33 SN |
107 | if (pdata->set_voltage && freqs.new > freqs.old) { |
108 | ret = pdata->set_voltage(idx); | |
109 | if (ret) | |
110 | goto out; | |
111 | } | |
6601b803 SN |
112 | |
113 | ret = clk_set_rate(armclk, idx); | |
fca97b33 SN |
114 | if (ret) |
115 | goto out; | |
6601b803 | 116 | |
30a2c5d2 SN |
117 | if (cpufreq.asyncclk) { |
118 | ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); | |
119 | if (ret) | |
120 | goto out; | |
121 | } | |
122 | ||
6601b803 SN |
123 | /* if moving to lower freq, lower the voltage after lowering freq */ |
124 | if (pdata->set_voltage && freqs.new < freqs.old) | |
125 | pdata->set_voltage(idx); | |
126 | ||
fca97b33 | 127 | out: |
b43a7ffb | 128 | cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE); |
6601b803 SN |
129 | |
130 | return ret; | |
131 | } | |
132 | ||
079db590 | 133 | static int davinci_cpu_init(struct cpufreq_policy *policy) |
6601b803 SN |
134 | { |
135 | int result = 0; | |
136 | struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data; | |
137 | struct cpufreq_frequency_table *freq_table = pdata->freq_table; | |
138 | ||
139 | if (policy->cpu != 0) | |
140 | return -EINVAL; | |
141 | ||
13d5e27a SN |
142 | /* Finish platform specific initialization */ |
143 | if (pdata->init) { | |
144 | result = pdata->init(); | |
145 | if (result) | |
146 | return result; | |
147 | } | |
148 | ||
6601b803 SN |
149 | policy->cur = policy->min = policy->max = davinci_getspeed(0); |
150 | ||
151 | if (freq_table) { | |
152 | result = cpufreq_frequency_table_cpuinfo(policy, freq_table); | |
153 | if (!result) | |
154 | cpufreq_frequency_table_get_attr(freq_table, | |
155 | policy->cpu); | |
156 | } else { | |
157 | policy->cpuinfo.min_freq = policy->min; | |
158 | policy->cpuinfo.max_freq = policy->max; | |
159 | } | |
160 | ||
161 | policy->min = policy->cpuinfo.min_freq; | |
162 | policy->max = policy->cpuinfo.max_freq; | |
163 | policy->cur = davinci_getspeed(0); | |
164 | ||
165 | /* | |
166 | * Time measurement across the target() function yields ~1500-1800us | |
167 | * time taken with no drivers on notification list. | |
25985edc | 168 | * Setting the latency to 2000 us to accommodate addition of drivers |
6601b803 SN |
169 | * to pre/post change notification list. |
170 | */ | |
171 | policy->cpuinfo.transition_latency = 2000 * 1000; | |
172 | return 0; | |
173 | } | |
174 | ||
175 | static int davinci_cpu_exit(struct cpufreq_policy *policy) | |
176 | { | |
177 | cpufreq_frequency_table_put_attr(policy->cpu); | |
178 | return 0; | |
179 | } | |
180 | ||
181 | static struct freq_attr *davinci_cpufreq_attr[] = { | |
182 | &cpufreq_freq_attr_scaling_available_freqs, | |
183 | NULL, | |
184 | }; | |
185 | ||
186 | static struct cpufreq_driver davinci_driver = { | |
187 | .flags = CPUFREQ_STICKY, | |
188 | .verify = davinci_verify_speed, | |
189 | .target = davinci_target, | |
190 | .get = davinci_getspeed, | |
191 | .init = davinci_cpu_init, | |
192 | .exit = davinci_cpu_exit, | |
193 | .name = "davinci", | |
194 | .attr = davinci_cpufreq_attr, | |
195 | }; | |
196 | ||
197 | static int __init davinci_cpufreq_probe(struct platform_device *pdev) | |
198 | { | |
199 | struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; | |
30a2c5d2 | 200 | struct clk *asyncclk; |
6601b803 SN |
201 | |
202 | if (!pdata) | |
203 | return -EINVAL; | |
204 | if (!pdata->freq_table) | |
205 | return -EINVAL; | |
206 | ||
207 | cpufreq.dev = &pdev->dev; | |
208 | ||
209 | cpufreq.armclk = clk_get(NULL, "arm"); | |
210 | if (IS_ERR(cpufreq.armclk)) { | |
211 | dev_err(cpufreq.dev, "Unable to get ARM clock\n"); | |
212 | return PTR_ERR(cpufreq.armclk); | |
213 | } | |
214 | ||
30a2c5d2 SN |
215 | asyncclk = clk_get(cpufreq.dev, "async"); |
216 | if (!IS_ERR(asyncclk)) { | |
217 | cpufreq.asyncclk = asyncclk; | |
218 | cpufreq.asyncrate = clk_get_rate(asyncclk); | |
219 | } | |
220 | ||
6601b803 SN |
221 | return cpufreq_register_driver(&davinci_driver); |
222 | } | |
223 | ||
224 | static int __exit davinci_cpufreq_remove(struct platform_device *pdev) | |
225 | { | |
226 | clk_put(cpufreq.armclk); | |
227 | ||
30a2c5d2 SN |
228 | if (cpufreq.asyncclk) |
229 | clk_put(cpufreq.asyncclk); | |
230 | ||
6601b803 SN |
231 | return cpufreq_unregister_driver(&davinci_driver); |
232 | } | |
233 | ||
234 | static struct platform_driver davinci_cpufreq_driver = { | |
235 | .driver = { | |
236 | .name = "cpufreq-davinci", | |
237 | .owner = THIS_MODULE, | |
238 | }, | |
239 | .remove = __exit_p(davinci_cpufreq_remove), | |
240 | }; | |
241 | ||
3aa3e840 | 242 | int __init davinci_cpufreq_init(void) |
6601b803 SN |
243 | { |
244 | return platform_driver_probe(&davinci_cpufreq_driver, | |
245 | davinci_cpufreq_probe); | |
246 | } | |
6601b803 | 247 |