tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (c) 2006-2008 Simtec Electronics
3 * http://armlinux.simtec.co.uk/
4 * Ben Dooks <ben@simtec.co.uk>
5 *
6 * S3C2410 CPU Frequency scaling
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11*/
12
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/interrupt.h>
16#include <linux/ioport.h>
17#include <linux/cpufreq.h>
18#include <linux/device.h>
19#include <linux/clk.h>
20#include <linux/err.h>
21#include <linux/io.h>
22
23#include <asm/mach/arch.h>
24#include <asm/mach/map.h>
25
26#include <mach/regs-clock.h>
27
28#include <plat/cpu.h>
29#include <plat/clock.h>
30#include <plat/cpu-freq-core.h>
31
32/* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
33
34static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
35{
36 u32 clkdiv = 0;
37
38 if (cfg->divs.h_divisor == 2)
39 clkdiv |= S3C2410_CLKDIVN_HDIVN;
40
41 if (cfg->divs.p_divisor != cfg->divs.h_divisor)
42 clkdiv |= S3C2410_CLKDIVN_PDIVN;
43
44 __raw_writel(clkdiv, S3C2410_CLKDIVN);
45}
46
47static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
48{
49 unsigned long hclk, fclk, pclk;
50 unsigned int hdiv, pdiv;
51 unsigned long hclk_max;
52
53 fclk = cfg->freq.fclk;
54 hclk_max = cfg->max.hclk;
55
56 cfg->freq.armclk = fclk;
57
58 s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
59 __func__, fclk, hclk_max);
60
61 hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
62 hclk = fclk / hdiv;
63
64 if (hclk > cfg->max.hclk) {
65 s3c_freq_dbg("%s: hclk too big\n", __func__);
66 return -EINVAL;
67 }
68
69 pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
70 pclk = hclk / pdiv;
71
72 if (pclk > cfg->max.pclk) {
73 s3c_freq_dbg("%s: pclk too big\n", __func__);
74 return -EINVAL;
75 }
76
77 pdiv *= hdiv;
78
79 /* record the result */
80 cfg->divs.p_divisor = pdiv;
81 cfg->divs.h_divisor = hdiv;
82
83 return 0;
84}
85
86static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
87 .max = {
88 .fclk = 200000000,
89 .hclk = 100000000,
90 .pclk = 50000000,
91 },
92
93 /* transition latency is about 5ms worst-case, so
94 * set 10ms to be sure */
95 .latency = 10000000,
96
97 .locktime_m = 150,
98 .locktime_u = 150,
99 .locktime_bits = 12,
100
101 .need_pll = 1,
102
103 .name = "s3c2410",
104 .calc_iotiming = s3c2410_iotiming_calc,
105 .set_iotiming = s3c2410_iotiming_set,
106 .get_iotiming = s3c2410_iotiming_get,
107 .resume_clocks = s3c2410_setup_clocks,
108
109 .set_fvco = s3c2410_set_fvco,
110 .set_refresh = s3c2410_cpufreq_setrefresh,
111 .set_divs = s3c2410_cpufreq_setdivs,
112 .calc_divs = s3c2410_cpufreq_calcdivs,
113
114 .debug_io_show = s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
115};
116
117static int s3c2410_cpufreq_add(struct device *dev,
118 struct subsys_interface *sif)
119{
120 return s3c_cpufreq_register(&s3c2410_cpufreq_info);
121}
122
123static struct subsys_interface s3c2410_cpufreq_interface = {
124 .name = "s3c2410_cpufreq",
125 .subsys = &s3c2410_subsys,
126 .add_dev = s3c2410_cpufreq_add,
127};
128
129static int __init s3c2410_cpufreq_init(void)
130{
131 return subsys_interface_register(&s3c2410_cpufreq_interface);
132}
133arch_initcall(s3c2410_cpufreq_init);
134
135static int s3c2410a_cpufreq_add(struct device *dev,
136 struct subsys_interface *sif)
137{
138 /* alter the maximum freq settings for S3C2410A. If a board knows
139 * it only has a maximum of 200, then it should register its own
140 * limits. */
141
142 s3c2410_cpufreq_info.max.fclk = 266000000;
143 s3c2410_cpufreq_info.max.hclk = 133000000;
144 s3c2410_cpufreq_info.max.pclk = 66500000;
145 s3c2410_cpufreq_info.name = "s3c2410a";
146
147 return s3c2410_cpufreq_add(dev, sif);
148}
149
150static struct subsys_interface s3c2410a_cpufreq_interface = {
151 .name = "s3c2410a_cpufreq",
152 .subsys = &s3c2410a_subsys,
153 .add_dev = s3c2410a_cpufreq_add,
154};
155
156static int __init s3c2410a_cpufreq_init(void)
157{
158 return subsys_interface_register(&s3c2410a_cpufreq_interface);
159}
160arch_initcall(s3c2410a_cpufreq_init);