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
|
/*
* CPU frequency scaling for Broadcom BMIPS SoCs
*
* Copyright (c) 2017 Broadcom
*
* 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 version 2.
*
* This program is distributed "as is" WITHOUT ANY WARRANTY of any
* kind, whether express or implied; without even the implied warranty
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/cpufreq.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <linux/slab.h>
/* for mips_hpt_frequency */
#include <asm/time.h>
#define BMIPS_CPUFREQ_PREFIX "bmips"
#define BMIPS_CPUFREQ_NAME BMIPS_CPUFREQ_PREFIX "-cpufreq"
#define TRANSITION_LATENCY (25 * 1000) /* 25 us */
#define BMIPS5_CLK_DIV_SET_SHIFT 0x7
#define BMIPS5_CLK_DIV_SHIFT 0x4
#define BMIPS5_CLK_DIV_MASK 0xf
enum bmips_type {
BMIPS5000,
BMIPS5200,
};
struct cpufreq_compat {
const char *compatible;
unsigned int bmips_type;
unsigned int clk_mult;
unsigned int max_freqs;
};
#define BMIPS(c, t, m, f) { \
.compatible = c, \
.bmips_type = (t), \
.clk_mult = (m), \
.max_freqs = (f), \
}
static struct cpufreq_compat bmips_cpufreq_compat[] = {
BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),
BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),
{ }
};
static struct cpufreq_compat *priv;
static int htp_freq_to_cpu_freq(unsigned int clk_mult)
{
return mips_hpt_frequency * clk_mult / 1000;
}
static struct cpufreq_frequency_table *
bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)
{
struct cpufreq_frequency_table *table;
unsigned long cpu_freq;
int i;
cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);
table = kmalloc((priv->max_freqs + 1) * sizeof(*table), GFP_KERNEL);
if (!table)
return ERR_PTR(-ENOMEM);
for (i = 0; i < priv->max_freqs; i++) {
table[i].frequency = cpu_freq / (1 << i);
table[i].driver_data = i;
}
table[i].frequency = CPUFREQ_TABLE_END;
return table;
}
static unsigned int bmips_cpufreq_get(unsigned int cpu)
{
unsigned int div;
uint32_t mode;
switch (priv->bmips_type) {
case BMIPS5200:
case BMIPS5000:
mode = read_c0_brcm_mode();
div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);
break;
default:
div = 0;
}
return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);
}
static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,
unsigned int index)
{
unsigned int div = policy->freq_table[index].driver_data;
switch (priv->bmips_type) {
case BMIPS5200:
case BMIPS5000:
change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,
(1 << BMIPS5_CLK_DIV_SET_SHIFT) |
(div << BMIPS5_CLK_DIV_SHIFT));
break;
default:
return -ENOTSUPP;
}
return 0;
}
static int bmips_cpufreq_exit(struct cpufreq_policy *policy)
{
kfree(policy->freq_table);
return 0;
}
static int bmips_cpufreq_init(struct cpufreq_policy *policy)
{
struct cpufreq_frequency_table *freq_table;
int ret;
freq_table = bmips_cpufreq_get_freq_table(policy);
if (IS_ERR(freq_table)) {
ret = PTR_ERR(freq_table);
pr_err("%s: couldn't determine frequency table (%d).\n",
BMIPS_CPUFREQ_NAME, ret);
return ret;
}
ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);
if (ret)
bmips_cpufreq_exit(policy);
else
pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);
return ret;
}
static struct cpufreq_driver bmips_cpufreq_driver = {
.flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = bmips_cpufreq_target_index,
.get = bmips_cpufreq_get,
.init = bmips_cpufreq_init,
.exit = bmips_cpufreq_exit,
.attr = cpufreq_generic_attr,
.name = BMIPS_CPUFREQ_PREFIX,
};
static int __init bmips_cpufreq_probe(void)
{
struct cpufreq_compat *cc;
struct device_node *np;
for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {
np = of_find_compatible_node(NULL, "cpu", cc->compatible);
if (np) {
of_node_put(np);
priv = cc;
break;
}
}
/* We hit the guard element of the array. No compatible CPU found. */
if (!cc->compatible)
return -ENODEV;
return cpufreq_register_driver(&bmips_cpufreq_driver);
}
device_initcall(bmips_cpufreq_probe);
MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");
MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");
MODULE_LICENSE("GPL");
|
