1/*
2 * File:         arch/blackfin/mach-bf537/cpu.c
3 * Based on:
4 * Author:       michael.kang@analog.com
5 *
6 * Created:
7 * Description:  clock scaling for the bf537
8 *
9 * Modified:
10 *               Copyright 2004-2006 Analog Devices Inc.
11 *
12 * Bugs:         Enter bugs at http://blackfin.uclinux.org/
13 *
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License as published by
16 * the Free Software Foundation; either version 2 of the License, or
17 * (at your option) any later version.
18 *
19 * This program is distributed in the hope that it will be useful,
20 * but WITHOUT ANY WARRANTY; without even the implied warranty of
21 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
22 * GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with this program; if not, see the file COPYING, or write
26 * to the Free Software Foundation, Inc.,
27 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
28 */
29
30#include <linux/kernel.h>
31#include <linux/types.h>
32#include <linux/init.h>
33#include <linux/cpufreq.h>
34#include <asm/dpmc.h>
35#include <linux/fs.h>
36#include <asm/bfin-global.h>
37
38/* CONFIG_CLKIN_HZ=11059200 */
39#define VCO5 (CONFIG_CLKIN_HZ*45)	/*497664000 */
40#define VCO4 (CONFIG_CLKIN_HZ*36)	/*398131200 */
41#define VCO3 (CONFIG_CLKIN_HZ*27)	/*298598400 */
42#define VCO2 (CONFIG_CLKIN_HZ*18)	/*199065600 */
43#define VCO1 (CONFIG_CLKIN_HZ*9)	/*99532800 */
44#define VCO(x) VCO##x
45
46#define MFREQ(x) {VCO(x),VCO(x)/4},{VCO(x),VCO(x)/2},{VCO(x),VCO(x)}
47/* frequency */
48static struct cpufreq_frequency_table bf537_freq_table[] = {
49	MFREQ(1),
50	MFREQ(3),
51	{VCO4, VCO4 / 2}, {VCO4, VCO4},
52	MFREQ(5),
53	{0, CPUFREQ_TABLE_END},
54};
55
56/*
57 * dpmc_fops->ioctl()
58 * static int dpmc_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
59 */
60static int bf537_getfreq(unsigned int cpu)
61{
62	unsigned long cclk_mhz;
63
64	/* The driver only support single cpu */
65	if (cpu == 0)
66		dpmc_fops.ioctl(NULL, NULL, IOCTL_GET_CORECLOCK, &cclk_mhz);
67	else
68		cclk_mhz = -1;
69
70	return cclk_mhz;
71}
72
73static int bf537_target(struct cpufreq_policy *policy,
74			    unsigned int target_freq, unsigned int relation)
75{
76	unsigned long cclk_mhz;
77	unsigned long vco_mhz;
78	unsigned long flags;
79	unsigned int index;
80	struct cpufreq_freqs freqs;
81
82	if (cpufreq_frequency_table_target(policy, bf537_freq_table, target_freq, relation, &index))
83		return -EINVAL;
84
85	cclk_mhz = bf537_freq_table[index].frequency;
86	vco_mhz = bf537_freq_table[index].index;
87
88	dpmc_fops.ioctl(NULL, NULL, IOCTL_CHANGE_FREQUENCY, &vco_mhz);
89	freqs.old = bf537_getfreq(0);
90	freqs.new = cclk_mhz;
91	freqs.cpu = 0;
92
93	pr_debug("cclk begin change to cclk %d,vco=%d,index=%d,target=%d,oldfreq=%d\n",
94	         cclk_mhz, vco_mhz, index, target_freq, freqs.old);
95
96	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
97	local_irq_save(flags);
98	dpmc_fops.ioctl(NULL, NULL, IOCTL_SET_CCLK, &cclk_mhz);
99	local_irq_restore(flags);
100	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
101
102	vco_mhz = get_vco();
103	cclk_mhz = get_cclk();
104	return 0;
105}
106
107/* make sure that only the "userspace" governor is run -- anything else wouldn't make sense on
108 * this platform, anyway.
109 */
110static int bf537_verify_speed(struct cpufreq_policy *policy)
111{
112	return cpufreq_frequency_table_verify(policy, &bf537_freq_table);
113}
114
115static int __init __bf537_cpu_init(struct cpufreq_policy *policy)
116{
117	if (policy->cpu != 0)
118		return -EINVAL;
119
120	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
121
122	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
123	/*Now ,only support one cpu */
124	policy->cur = bf537_getfreq(0);
125	cpufreq_frequency_table_get_attr(bf537_freq_table, policy->cpu);
126	return cpufreq_frequency_table_cpuinfo(policy, bf537_freq_table);
127}
128
129static struct freq_attr *bf537_freq_attr[] = {
130	&cpufreq_freq_attr_scaling_available_freqs,
131	NULL,
132};
133
134static struct cpufreq_driver bf537_driver = {
135	.verify = bf537_verify_speed,
136	.target = bf537_target,
137	.get = bf537_getfreq,
138	.init = __bf537_cpu_init,
139	.name = "bf537",
140	.owner = THIS_MODULE,
141	.attr = bf537_freq_attr,
142};
143
144static int __init bf537_cpu_init(void)
145{
146	return cpufreq_register_driver(&bf537_driver);
147}
148
149static void __exit bf537_cpu_exit(void)
150{
151	cpufreq_unregister_driver(&bf537_driver);
152}
153
154MODULE_AUTHOR("Mickael Kang");
155MODULE_DESCRIPTION("cpufreq driver for BF537 CPU");
156MODULE_LICENSE("GPL");
157
158module_init(bf537_cpu_init);
159module_exit(bf537_cpu_exit);
160