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Sekhar Nori6601b802009-09-22 21:14:00 +05301/*
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>
27
28#include <mach/hardware.h>
29#include <mach/cpufreq.h>
30#include <mach/common.h>
31
32#include "clock.h"
33
34struct davinci_cpufreq {
35 struct device *dev;
36 struct clk *armclk;
37};
38static struct davinci_cpufreq cpufreq;
39
40static int davinci_verify_speed(struct cpufreq_policy *policy)
41{
42 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
43 struct cpufreq_frequency_table *freq_table = pdata->freq_table;
44 struct clk *armclk = cpufreq.armclk;
45
46 if (freq_table)
47 return cpufreq_frequency_table_verify(policy, freq_table);
48
49 if (policy->cpu)
50 return -EINVAL;
51
52 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
53 policy->cpuinfo.max_freq);
54
55 policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000;
56 policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000;
57 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
58 policy->cpuinfo.max_freq);
59 return 0;
60}
61
62static unsigned int davinci_getspeed(unsigned int cpu)
63{
64 if (cpu)
65 return 0;
66
67 return clk_get_rate(cpufreq.armclk) / 1000;
68}
69
70static int davinci_target(struct cpufreq_policy *policy,
71 unsigned int target_freq, unsigned int relation)
72{
73 int ret = 0;
74 unsigned int idx;
75 struct cpufreq_freqs freqs;
76 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
77 struct clk *armclk = cpufreq.armclk;
78
79 /*
80 * Ensure desired rate is within allowed range. Some govenors
81 * (ondemand) will just pass target_freq=0 to get the minimum.
82 */
83 if (target_freq < policy->cpuinfo.min_freq)
84 target_freq = policy->cpuinfo.min_freq;
85 if (target_freq > policy->cpuinfo.max_freq)
86 target_freq = policy->cpuinfo.max_freq;
87
88 freqs.old = davinci_getspeed(0);
89 freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000;
90 freqs.cpu = 0;
91
92 if (freqs.old == freqs.new)
93 return ret;
94
95 cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER,
96 dev_driver_string(cpufreq.dev),
97 "transition: %u --> %u\n", freqs.old, freqs.new);
98
99 ret = cpufreq_frequency_table_target(policy, pdata->freq_table,
100 freqs.new, relation, &idx);
101 if (ret)
102 return -EINVAL;
103
104 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
105
106 /* if moving to higher frequency, up the voltage beforehand */
107 if (pdata->set_voltage && freqs.new > freqs.old)
108 pdata->set_voltage(idx);
109
110 ret = clk_set_rate(armclk, idx);
111
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
116 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
117
118 return ret;
119}
120
121static int __init davinci_cpu_init(struct cpufreq_policy *policy)
122{
123 int result = 0;
124 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
125 struct cpufreq_frequency_table *freq_table = pdata->freq_table;
126
127 if (policy->cpu != 0)
128 return -EINVAL;
129
Sekhar Nori13d5e272009-10-22 15:12:16 +0530130 /* Finish platform specific initialization */
131 if (pdata->init) {
132 result = pdata->init();
133 if (result)
134 return result;
135 }
136
Sekhar Nori6601b802009-09-22 21:14:00 +0530137 policy->cur = policy->min = policy->max = davinci_getspeed(0);
138
139 if (freq_table) {
140 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
141 if (!result)
142 cpufreq_frequency_table_get_attr(freq_table,
143 policy->cpu);
144 } else {
145 policy->cpuinfo.min_freq = policy->min;
146 policy->cpuinfo.max_freq = policy->max;
147 }
148
149 policy->min = policy->cpuinfo.min_freq;
150 policy->max = policy->cpuinfo.max_freq;
151 policy->cur = davinci_getspeed(0);
152
153 /*
154 * Time measurement across the target() function yields ~1500-1800us
155 * time taken with no drivers on notification list.
156 * Setting the latency to 2000 us to accomodate addition of drivers
157 * to pre/post change notification list.
158 */
159 policy->cpuinfo.transition_latency = 2000 * 1000;
160 return 0;
161}
162
163static int davinci_cpu_exit(struct cpufreq_policy *policy)
164{
165 cpufreq_frequency_table_put_attr(policy->cpu);
166 return 0;
167}
168
169static struct freq_attr *davinci_cpufreq_attr[] = {
170 &cpufreq_freq_attr_scaling_available_freqs,
171 NULL,
172};
173
174static struct cpufreq_driver davinci_driver = {
175 .flags = CPUFREQ_STICKY,
176 .verify = davinci_verify_speed,
177 .target = davinci_target,
178 .get = davinci_getspeed,
179 .init = davinci_cpu_init,
180 .exit = davinci_cpu_exit,
181 .name = "davinci",
182 .attr = davinci_cpufreq_attr,
183};
184
185static int __init davinci_cpufreq_probe(struct platform_device *pdev)
186{
187 struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
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
202 return cpufreq_register_driver(&davinci_driver);
203}
204
205static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
206{
207 clk_put(cpufreq.armclk);
208
209 return cpufreq_unregister_driver(&davinci_driver);
210}
211
212static struct platform_driver davinci_cpufreq_driver = {
213 .driver = {
214 .name = "cpufreq-davinci",
215 .owner = THIS_MODULE,
216 },
217 .remove = __exit_p(davinci_cpufreq_remove),
218};
219
220static int __init davinci_cpufreq_init(void)
221{
222 return platform_driver_probe(&davinci_cpufreq_driver,
223 davinci_cpufreq_probe);
224}
225late_initcall(davinci_cpufreq_init);
226