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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;
Sekhar Nori30a2c5d2010-07-20 16:46:50 +053037 struct clk *asyncclk;
38 unsigned long asyncrate;
Sekhar Nori6601b802009-09-22 21:14:00 +053039};
40static struct davinci_cpufreq cpufreq;
41
42static int davinci_verify_speed(struct cpufreq_policy *policy)
43{
44 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
45 struct cpufreq_frequency_table *freq_table = pdata->freq_table;
46 struct clk *armclk = cpufreq.armclk;
47
48 if (freq_table)
49 return cpufreq_frequency_table_verify(policy, freq_table);
50
51 if (policy->cpu)
52 return -EINVAL;
53
54 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
55 policy->cpuinfo.max_freq);
56
57 policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000;
58 policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000;
59 cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
60 policy->cpuinfo.max_freq);
61 return 0;
62}
63
64static unsigned int davinci_getspeed(unsigned int cpu)
65{
66 if (cpu)
67 return 0;
68
69 return clk_get_rate(cpufreq.armclk) / 1000;
70}
71
72static int davinci_target(struct cpufreq_policy *policy,
73 unsigned int target_freq, unsigned int relation)
74{
75 int ret = 0;
76 unsigned int idx;
77 struct cpufreq_freqs freqs;
78 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
79 struct clk *armclk = cpufreq.armclk;
80
81 /*
82 * Ensure desired rate is within allowed range. Some govenors
83 * (ondemand) will just pass target_freq=0 to get the minimum.
84 */
85 if (target_freq < policy->cpuinfo.min_freq)
86 target_freq = policy->cpuinfo.min_freq;
87 if (target_freq > policy->cpuinfo.max_freq)
88 target_freq = policy->cpuinfo.max_freq;
89
90 freqs.old = davinci_getspeed(0);
91 freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000;
92 freqs.cpu = 0;
93
94 if (freqs.old == freqs.new)
95 return ret;
96
97 cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER,
98 dev_driver_string(cpufreq.dev),
99 "transition: %u --> %u\n", freqs.old, freqs.new);
100
101 ret = cpufreq_frequency_table_target(policy, pdata->freq_table,
102 freqs.new, relation, &idx);
103 if (ret)
104 return -EINVAL;
105
106 cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
107
108 /* if moving to higher frequency, up the voltage beforehand */
Sekhar Norifca97b32010-07-20 16:46:48 +0530109 if (pdata->set_voltage && freqs.new > freqs.old) {
110 ret = pdata->set_voltage(idx);
111 if (ret)
112 goto out;
113 }
Sekhar Nori6601b802009-09-22 21:14:00 +0530114
115 ret = clk_set_rate(armclk, idx);
Sekhar Norifca97b32010-07-20 16:46:48 +0530116 if (ret)
117 goto out;
Sekhar Nori6601b802009-09-22 21:14:00 +0530118
Sekhar Nori30a2c5d2010-07-20 16:46:50 +0530119 if (cpufreq.asyncclk) {
120 ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
121 if (ret)
122 goto out;
123 }
124
Sekhar Nori6601b802009-09-22 21:14:00 +0530125 /* if moving to lower freq, lower the voltage after lowering freq */
126 if (pdata->set_voltage && freqs.new < freqs.old)
127 pdata->set_voltage(idx);
128
Sekhar Norifca97b32010-07-20 16:46:48 +0530129out:
Sekhar Nori6601b802009-09-22 21:14:00 +0530130 cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
131
132 return ret;
133}
134
Axel Lin079db592011-02-28 15:51:33 +0530135static int davinci_cpu_init(struct cpufreq_policy *policy)
Sekhar Nori6601b802009-09-22 21:14:00 +0530136{
137 int result = 0;
138 struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
139 struct cpufreq_frequency_table *freq_table = pdata->freq_table;
140
141 if (policy->cpu != 0)
142 return -EINVAL;
143
Sekhar Nori13d5e272009-10-22 15:12:16 +0530144 /* Finish platform specific initialization */
145 if (pdata->init) {
146 result = pdata->init();
147 if (result)
148 return result;
149 }
150
Sekhar Nori6601b802009-09-22 21:14:00 +0530151 policy->cur = policy->min = policy->max = davinci_getspeed(0);
152
153 if (freq_table) {
154 result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
155 if (!result)
156 cpufreq_frequency_table_get_attr(freq_table,
157 policy->cpu);
158 } else {
159 policy->cpuinfo.min_freq = policy->min;
160 policy->cpuinfo.max_freq = policy->max;
161 }
162
163 policy->min = policy->cpuinfo.min_freq;
164 policy->max = policy->cpuinfo.max_freq;
165 policy->cur = davinci_getspeed(0);
166
167 /*
168 * Time measurement across the target() function yields ~1500-1800us
169 * time taken with no drivers on notification list.
170 * Setting the latency to 2000 us to accomodate addition of drivers
171 * to pre/post change notification list.
172 */
173 policy->cpuinfo.transition_latency = 2000 * 1000;
174 return 0;
175}
176
177static int davinci_cpu_exit(struct cpufreq_policy *policy)
178{
179 cpufreq_frequency_table_put_attr(policy->cpu);
180 return 0;
181}
182
183static struct freq_attr *davinci_cpufreq_attr[] = {
184 &cpufreq_freq_attr_scaling_available_freqs,
185 NULL,
186};
187
188static struct cpufreq_driver davinci_driver = {
189 .flags = CPUFREQ_STICKY,
190 .verify = davinci_verify_speed,
191 .target = davinci_target,
192 .get = davinci_getspeed,
193 .init = davinci_cpu_init,
194 .exit = davinci_cpu_exit,
195 .name = "davinci",
196 .attr = davinci_cpufreq_attr,
197};
198
199static int __init davinci_cpufreq_probe(struct platform_device *pdev)
200{
201 struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
Sekhar Nori30a2c5d2010-07-20 16:46:50 +0530202 struct clk *asyncclk;
Sekhar Nori6601b802009-09-22 21:14:00 +0530203
204 if (!pdata)
205 return -EINVAL;
206 if (!pdata->freq_table)
207 return -EINVAL;
208
209 cpufreq.dev = &pdev->dev;
210
211 cpufreq.armclk = clk_get(NULL, "arm");
212 if (IS_ERR(cpufreq.armclk)) {
213 dev_err(cpufreq.dev, "Unable to get ARM clock\n");
214 return PTR_ERR(cpufreq.armclk);
215 }
216
Sekhar Nori30a2c5d2010-07-20 16:46:50 +0530217 asyncclk = clk_get(cpufreq.dev, "async");
218 if (!IS_ERR(asyncclk)) {
219 cpufreq.asyncclk = asyncclk;
220 cpufreq.asyncrate = clk_get_rate(asyncclk);
221 }
222
Sekhar Nori6601b802009-09-22 21:14:00 +0530223 return cpufreq_register_driver(&davinci_driver);
224}
225
226static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
227{
228 clk_put(cpufreq.armclk);
229
Sekhar Nori30a2c5d2010-07-20 16:46:50 +0530230 if (cpufreq.asyncclk)
231 clk_put(cpufreq.asyncclk);
232
Sekhar Nori6601b802009-09-22 21:14:00 +0530233 return cpufreq_unregister_driver(&davinci_driver);
234}
235
236static struct platform_driver davinci_cpufreq_driver = {
237 .driver = {
238 .name = "cpufreq-davinci",
239 .owner = THIS_MODULE,
240 },
241 .remove = __exit_p(davinci_cpufreq_remove),
242};
243
244static int __init davinci_cpufreq_init(void)
245{
246 return platform_driver_probe(&davinci_cpufreq_driver,
247 davinci_cpufreq_probe);
248}
249late_initcall(davinci_cpufreq_init);
250