[go: nahoru, domu]
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/cpu-freq-core.h>
30
31/* Note, 2410A has an extra mode for 1:4:4 ratio, bit 2 of CLKDIV */
32
33static void s3c2410_cpufreq_setdivs(struct s3c_cpufreq_config *cfg)
34{
35	u32 clkdiv = 0;
36
37	if (cfg->divs.h_divisor == 2)
38		clkdiv |= S3C2410_CLKDIVN_HDIVN;
39
40	if (cfg->divs.p_divisor != cfg->divs.h_divisor)
41		clkdiv |= S3C2410_CLKDIVN_PDIVN;
42
43	__raw_writel(clkdiv, S3C2410_CLKDIVN);
44}
45
46static int s3c2410_cpufreq_calcdivs(struct s3c_cpufreq_config *cfg)
47{
48	unsigned long hclk, fclk, pclk;
49	unsigned int hdiv, pdiv;
50	unsigned long hclk_max;
51
52	fclk = cfg->freq.fclk;
53	hclk_max = cfg->max.hclk;
54
55	cfg->freq.armclk = fclk;
56
57	s3c_freq_dbg("%s: fclk is %lu, max hclk %lu\n",
58		      __func__, fclk, hclk_max);
59
60	hdiv = (fclk > cfg->max.hclk) ? 2 : 1;
61	hclk = fclk / hdiv;
62
63	if (hclk > cfg->max.hclk) {
64		s3c_freq_dbg("%s: hclk too big\n", __func__);
65		return -EINVAL;
66	}
67
68	pdiv = (hclk > cfg->max.pclk) ? 2 : 1;
69	pclk = hclk / pdiv;
70
71	if (pclk > cfg->max.pclk) {
72		s3c_freq_dbg("%s: pclk too big\n", __func__);
73		return -EINVAL;
74	}
75
76	pdiv *= hdiv;
77
78	/* record the result */
79	cfg->divs.p_divisor = pdiv;
80	cfg->divs.h_divisor = hdiv;
81
82	return 0;
83}
84
85static struct s3c_cpufreq_info s3c2410_cpufreq_info = {
86	.max		= {
87		.fclk	= 200000000,
88		.hclk	= 100000000,
89		.pclk	=  50000000,
90	},
91
92	/* transition latency is about 5ms worst-case, so
93	 * set 10ms to be sure */
94	.latency	= 10000000,
95
96	.locktime_m	= 150,
97	.locktime_u	= 150,
98	.locktime_bits	= 12,
99
100	.need_pll	= 1,
101
102	.name		= "s3c2410",
103	.calc_iotiming	= s3c2410_iotiming_calc,
104	.set_iotiming	= s3c2410_iotiming_set,
105	.get_iotiming	= s3c2410_iotiming_get,
106
107	.set_fvco	= s3c2410_set_fvco,
108	.set_refresh	= s3c2410_cpufreq_setrefresh,
109	.set_divs	= s3c2410_cpufreq_setdivs,
110	.calc_divs	= s3c2410_cpufreq_calcdivs,
111
112	.debug_io_show	= s3c_cpufreq_debugfs_call(s3c2410_iotiming_debugfs),
113};
114
115static int s3c2410_cpufreq_add(struct device *dev,
116			       struct subsys_interface *sif)
117{
118	return s3c_cpufreq_register(&s3c2410_cpufreq_info);
119}
120
121static struct subsys_interface s3c2410_cpufreq_interface = {
122	.name		= "s3c2410_cpufreq",
123	.subsys		= &s3c2410_subsys,
124	.add_dev	= s3c2410_cpufreq_add,
125};
126
127static int __init s3c2410_cpufreq_init(void)
128{
129	return subsys_interface_register(&s3c2410_cpufreq_interface);
130}
131arch_initcall(s3c2410_cpufreq_init);
132
133static int s3c2410a_cpufreq_add(struct device *dev,
134				struct subsys_interface *sif)
135{
136	/* alter the maximum freq settings for S3C2410A. If a board knows
137	 * it only has a maximum of 200, then it should register its own
138	 * limits. */
139
140	s3c2410_cpufreq_info.max.fclk = 266000000;
141	s3c2410_cpufreq_info.max.hclk = 133000000;
142	s3c2410_cpufreq_info.max.pclk =  66500000;
143	s3c2410_cpufreq_info.name = "s3c2410a";
144
145	return s3c2410_cpufreq_add(dev, sif);
146}
147
148static struct subsys_interface s3c2410a_cpufreq_interface = {
149	.name		= "s3c2410a_cpufreq",
150	.subsys		= &s3c2410a_subsys,
151	.add_dev	= s3c2410a_cpufreq_add,
152};
153
154static int __init s3c2410a_cpufreq_init(void)
155{
156	return subsys_interface_register(&s3c2410a_cpufreq_interface);
157}
158arch_initcall(s3c2410a_cpufreq_init);
159