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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> | |
27 | ||
28 | #include <mach/hardware.h> | |
29 | #include <mach/cpufreq.h> | |
30 | #include <mach/common.h> | |
31 | ||
32 | #include "clock.h" | |
33 | ||
34 | struct davinci_cpufreq { | |
35 | struct device *dev; | |
36 | struct clk *armclk; | |
30a2c5d2 SN |
37 | struct clk *asyncclk; |
38 | unsigned long asyncrate; | |
6601b803 SN |
39 | }; |
40 | static struct davinci_cpufreq cpufreq; | |
41 | ||
42 | static 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 | ||
64 | static 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 | ||
72 | static 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 */ | |
fca97b33 SN |
109 | if (pdata->set_voltage && freqs.new > freqs.old) { |
110 | ret = pdata->set_voltage(idx); | |
111 | if (ret) | |
112 | goto out; | |
113 | } | |
6601b803 SN |
114 | |
115 | ret = clk_set_rate(armclk, idx); | |
fca97b33 SN |
116 | if (ret) |
117 | goto out; | |
6601b803 | 118 | |
30a2c5d2 SN |
119 | if (cpufreq.asyncclk) { |
120 | ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate); | |
121 | if (ret) | |
122 | goto out; | |
123 | } | |
124 | ||
6601b803 SN |
125 | /* 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 | ||
fca97b33 | 129 | out: |
6601b803 SN |
130 | cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
131 | ||
132 | return ret; | |
133 | } | |
134 | ||
079db590 | 135 | static int davinci_cpu_init(struct cpufreq_policy *policy) |
6601b803 SN |
136 | { |
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 | ||
13d5e27a SN |
144 | /* Finish platform specific initialization */ |
145 | if (pdata->init) { | |
146 | result = pdata->init(); | |
147 | if (result) | |
148 | return result; | |
149 | } | |
150 | ||
6601b803 SN |
151 | 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. | |
25985edc | 170 | * Setting the latency to 2000 us to accommodate addition of drivers |
6601b803 SN |
171 | * to pre/post change notification list. |
172 | */ | |
173 | policy->cpuinfo.transition_latency = 2000 * 1000; | |
174 | return 0; | |
175 | } | |
176 | ||
177 | static int davinci_cpu_exit(struct cpufreq_policy *policy) | |
178 | { | |
179 | cpufreq_frequency_table_put_attr(policy->cpu); | |
180 | return 0; | |
181 | } | |
182 | ||
183 | static struct freq_attr *davinci_cpufreq_attr[] = { | |
184 | &cpufreq_freq_attr_scaling_available_freqs, | |
185 | NULL, | |
186 | }; | |
187 | ||
188 | static 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 | ||
199 | static int __init davinci_cpufreq_probe(struct platform_device *pdev) | |
200 | { | |
201 | struct davinci_cpufreq_config *pdata = pdev->dev.platform_data; | |
30a2c5d2 | 202 | struct clk *asyncclk; |
6601b803 SN |
203 | |
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 | ||
30a2c5d2 SN |
217 | asyncclk = clk_get(cpufreq.dev, "async"); |
218 | if (!IS_ERR(asyncclk)) { | |
219 | cpufreq.asyncclk = asyncclk; | |
220 | cpufreq.asyncrate = clk_get_rate(asyncclk); | |
221 | } | |
222 | ||
6601b803 SN |
223 | return cpufreq_register_driver(&davinci_driver); |
224 | } | |
225 | ||
226 | static int __exit davinci_cpufreq_remove(struct platform_device *pdev) | |
227 | { | |
228 | clk_put(cpufreq.armclk); | |
229 | ||
30a2c5d2 SN |
230 | if (cpufreq.asyncclk) |
231 | clk_put(cpufreq.asyncclk); | |
232 | ||
6601b803 SN |
233 | return cpufreq_unregister_driver(&davinci_driver); |
234 | } | |
235 | ||
236 | static 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 | ||
244 | static int __init davinci_cpufreq_init(void) | |
245 | { | |
246 | return platform_driver_probe(&davinci_cpufreq_driver, | |
247 | davinci_cpufreq_probe); | |
248 | } | |
249 | late_initcall(davinci_cpufreq_init); | |
250 |