1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
/*
* File: arch/blackfin/mach-common/cpufreq.c
* Based on:
* Author:
*
* Created:
* Description: Blackfin core clock scaling
*
* Modified:
* Copyright 2004-2008 Analog Devices Inc.
*
* Bugs: Enter bugs at http://blackfin.uclinux.org/
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see the file COPYING, or write
* to the Free Software Foundation, Inc.,
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/fs.h>
#include <asm/blackfin.h>
#include <asm/time.h>
/* this is the table of CCLK frequencies, in Hz */
/* .index is the entry in the auxillary dpm_state_table[] */
static struct cpufreq_frequency_table bfin_freq_table[] = {
{
.frequency = CPUFREQ_TABLE_END,
.index = 0,
},
{
.frequency = CPUFREQ_TABLE_END,
.index = 1,
},
{
.frequency = CPUFREQ_TABLE_END,
.index = 2,
},
{
.frequency = CPUFREQ_TABLE_END,
.index = 0,
},
};
static struct bfin_dpm_state {
unsigned int csel; /* system clock divider */
unsigned int tscale; /* change the divider on the core timer interrupt */
} dpm_state_table[3];
/*
normalized to maximum frequncy offset for CYCLES,
used in time-ts cycles clock source, but could be used
somewhere also.
*/
unsigned long long __bfin_cycles_off;
unsigned int __bfin_cycles_mod;
/**************************************************************************/
static unsigned int bfin_getfreq_khz(unsigned int cpu)
{
/* The driver only support single cpu */
if (cpu != 0)
return -1;
return get_cclk() / 1000;
}
static int bfin_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
unsigned int index, plldiv, tscale;
unsigned long flags, cclk_hz;
struct cpufreq_freqs freqs;
cycles_t cycles;
if (cpufreq_frequency_table_target(policy, bfin_freq_table,
target_freq, relation, &index))
return -EINVAL;
cclk_hz = bfin_freq_table[index].frequency;
freqs.old = bfin_getfreq_khz(0);
freqs.new = cclk_hz;
freqs.cpu = 0;
pr_debug("cpufreq: changing cclk to %lu; target = %u, oldfreq = %u\n",
cclk_hz, target_freq, freqs.old);
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
local_irq_save_hw(flags);
plldiv = (bfin_read_PLL_DIV() & SSEL) | dpm_state_table[index].csel;
tscale = dpm_state_table[index].tscale;
bfin_write_PLL_DIV(plldiv);
/* we have to adjust the core timer, because it is using cclk */
bfin_write_TSCALE(tscale);
cycles = get_cycles();
SSYNC();
cycles += 10; /* ~10 cycles we lose after get_cycles() */
__bfin_cycles_off += (cycles << __bfin_cycles_mod) - (cycles << index);
__bfin_cycles_mod = index;
local_irq_restore_hw(flags);
/* TODO: just test case for cycles clock source, remove later */
pr_debug("cpufreq: done\n");
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static int bfin_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, bfin_freq_table);
}
static int __init __bfin_cpu_init(struct cpufreq_policy *policy)
{
unsigned long cclk, sclk, csel, min_cclk;
int index;
if (policy->cpu != 0)
return -EINVAL;
cclk = get_cclk() / 1000;
sclk = get_sclk() / 1000;
#if ANOMALY_05000273 || (!defined(CONFIG_BF54x) && defined(CONFIG_BFIN_DCACHE))
min_cclk = sclk * 2;
#else
min_cclk = sclk;
#endif
csel = ((bfin_read_PLL_DIV() & CSEL) >> 4);
for (index = 0; (cclk >> index) >= min_cclk && csel <= 3; index++, csel++) {
bfin_freq_table[index].frequency = cclk >> index;
dpm_state_table[index].csel = csel << 4; /* Shift now into PLL_DIV bitpos */
dpm_state_table[index].tscale = (TIME_SCALE / (1 << csel)) - 1;
pr_debug("cpufreq: freq:%d csel:0x%x tscale:%d\n",
bfin_freq_table[index].frequency,
dpm_state_table[index].csel,
dpm_state_table[index].tscale);
}
policy->cpuinfo.transition_latency = (bfin_read_PLL_LOCKCNT() / (sclk / 1000000)) * 1000;
/*Now ,only support one cpu */
policy->cur = cclk;
cpufreq_frequency_table_get_attr(bfin_freq_table, policy->cpu);
return cpufreq_frequency_table_cpuinfo(policy, bfin_freq_table);
}
static struct freq_attr *bfin_freq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static struct cpufreq_driver bfin_driver = {
.verify = bfin_verify_speed,
.target = bfin_target,
.get = bfin_getfreq_khz,
.init = __bfin_cpu_init,
.name = "bfin cpufreq",
.owner = THIS_MODULE,
.attr = bfin_freq_attr,
};
static int __init bfin_cpu_init(void)
{
return cpufreq_register_driver(&bfin_driver);
}
static void __exit bfin_cpu_exit(void)
{
cpufreq_unregister_driver(&bfin_driver);
}
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("cpufreq driver for Blackfin");
MODULE_LICENSE("GPL");
module_init(bfin_cpu_init);
module_exit(bfin_cpu_exit);
|
