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
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
|
/*
* cpu.c: clock scaling for the iMX
*
* Copyright (C) 2000 2001, The Delft University of Technology
* Copyright (c) 2004 Sascha Hauer <sascha@saschahauer.de>
* Copyright (C) 2006 Inky Lung <ilung@cwlinux.com>
* Copyright (C) 2006 Pavel Pisa, PiKRON <ppisa@pikron.com>
*
* Based on SA1100 version written by:
* - Johan Pouwelse (J.A.Pouwelse@its.tudelft.nl): initial version
* - Erik Mouw (J.A.K.Mouw@its.tudelft.nl):
*
* 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
/*#define DEBUG*/
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <asm/system.h>
#include <asm/hardware.h>
#include "generic.h"
#ifndef __val2mfld
#define __val2mfld(mask,val) (((mask)&~((mask)<<1))*(val)&(mask))
#endif
#ifndef __mfld2val
#define __mfld2val(mask,val) (((val)&(mask))/((mask)&~((mask)<<1)))
#endif
#define CR_920T_CLOCK_MODE 0xC0000000
#define CR_920T_FASTBUS_MODE 0x00000000
#define CR_920T_ASYNC_MODE 0xC0000000
static u32 mpctl0_at_boot;
static void imx_set_async_mode(void)
{
adjust_cr(CR_920T_CLOCK_MODE, CR_920T_ASYNC_MODE);
}
static void imx_set_fastbus_mode(void)
{
adjust_cr(CR_920T_CLOCK_MODE, CR_920T_FASTBUS_MODE);
}
static void imx_set_mpctl0(u32 mpctl0)
{
unsigned long flags;
if (mpctl0 == 0) {
local_irq_save(flags);
CSCR &= ~CSCR_MPEN;
local_irq_restore(flags);
return;
}
local_irq_save(flags);
MPCTL0 = mpctl0;
CSCR |= CSCR_MPEN;
local_irq_restore(flags);
}
/**
* imx_compute_mpctl - compute new PLL parameters
* @new_mpctl: pointer to location assigned by new PLL control register value
* @cur_mpctl: current PLL control register parameters
* @freq: required frequency in Hz
* @relation: is one of %CPUFREQ_RELATION_L (supremum)
* and %CPUFREQ_RELATION_H (infimum)
*/
long imx_compute_mpctl(u32 *new_mpctl, u32 cur_mpctl, unsigned long freq, int relation)
{
u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512);
u32 mfi;
u32 mfn;
u32 mfd;
u32 pd;
unsigned long long ll;
long l;
long quot;
/* Fdppl=2*Fref*(MFI+MFN/(MFD+1))/(PD+1) */
/* PD=<0,15>, MFD=<1,1023>, MFI=<5,15> MFN=<0,1022> */
if (cur_mpctl) {
mfd = ((cur_mpctl >> 16) & 0x3ff) + 1;
pd = ((cur_mpctl >> 26) & 0xf) + 1;
} else {
pd=2; mfd=313;
}
/* pd=2; mfd=313; mfi=8; mfn=183; */
/* (MFI+MFN/(MFD)) = Fdppl / (2*Fref) * (PD); */
quot = (f_ref + (1 << 9)) >> 10;
l = (freq * pd + quot) / (2 * quot);
mfi = l >> 10;
mfn = ((l & ((1 << 10) - 1)) * mfd + (1 << 9)) >> 10;
mfd -= 1;
pd -= 1;
*new_mpctl = ((mfi & 0xf) << 10) | (mfn & 0x3ff) | ((mfd & 0x3ff) << 16)
| ((pd & 0xf) << 26);
ll = 2 * (unsigned long long)f_ref * ( (mfi<<16) + (mfn<<16) / (mfd+1) );
quot = (pd+1) * (1<<16);
ll += quot / 2;
do_div(ll, quot);
freq = ll;
pr_debug(KERN_DEBUG "imx: new PLL parameters pd=%d mfd=%d mfi=%d mfn=%d, freq=%ld\n",
pd, mfd, mfi, mfn, freq);
return freq;
}
static int imx_verify_speed(struct cpufreq_policy *policy)
{
if (policy->cpu != 0)
return -EINVAL;
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, policy->cpuinfo.max_freq);
return 0;
}
static unsigned int imx_get_speed(unsigned int cpu)
{
unsigned int freq;
unsigned int cr;
unsigned int cscr;
unsigned int bclk_div;
if (cpu)
return 0;
cscr = CSCR;
bclk_div = __mfld2val(CSCR_BCLK_DIV, cscr) + 1;
cr = get_cr();
if((cr & CR_920T_CLOCK_MODE) == CR_920T_FASTBUS_MODE) {
freq = imx_get_system_clk();
freq = (freq + bclk_div/2) / bclk_div;
} else {
freq = imx_get_mcu_clk();
if (cscr & CSCR_MPU_PRESC)
freq /= 2;
}
freq = (freq + 500) / 1000;
return freq;
}
static int imx_set_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
u32 mpctl0 = 0;
u32 cscr;
unsigned long flags;
long freq;
long sysclk;
unsigned int bclk_div = 1;
freq = target_freq * 1000;
pr_debug(KERN_DEBUG "imx: requested frequency %ld Hz, mpctl0 at boot 0x%08x\n",
freq, mpctl0_at_boot);
sysclk = imx_get_system_clk();
if (freq > sysclk + 1000000) {
freq = imx_compute_mpctl(&mpctl0, mpctl0_at_boot, freq, relation);
if (freq < 0) {
printk(KERN_WARNING "imx: target frequency %ld Hz cannot be set\n", freq);
return -EINVAL;
}
} else {
if(freq + 1000 < sysclk) {
if (relation == CPUFREQ_RELATION_L)
bclk_div = (sysclk - 1000) / freq;
else
bclk_div = (sysclk + freq + 1000) / freq;
if(bclk_div > 16)
bclk_div = 16;
}
freq = (sysclk + bclk_div / 2) / bclk_div;
}
freqs.old = imx_get_speed(0);
freqs.new = (freq + 500) / 1000;
freqs.cpu = 0;
freqs.flags = 0;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
local_irq_save(flags);
imx_set_fastbus_mode();
imx_set_mpctl0(mpctl0);
cscr = CSCR;
cscr &= ~CSCR_BCLK_DIV;
cscr |= __val2mfld(CSCR_BCLK_DIV, bclk_div - 1);
CSCR = cscr;
if(mpctl0) {
CSCR |= CSCR_MPLL_RESTART;
/* Wait until MPLL is stablized */
while( CSCR & CSCR_MPLL_RESTART );
imx_set_async_mode();
}
local_irq_restore(flags);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
pr_debug(KERN_INFO "imx: set frequency %ld Hz, running from %s\n",
freq, mpctl0? "MPLL": "SPLL");
return 0;
}
static int __init imx_cpufreq_driver_init(struct cpufreq_policy *policy)
{
printk(KERN_INFO "i.MX cpu freq change driver v1.0\n");
if (policy->cpu != 0)
return -EINVAL;
policy->cur = policy->min = policy->max = imx_get_speed(0);
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cpuinfo.min_freq = 8000;
policy->cpuinfo.max_freq = 200000;
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
return 0;
}
static struct cpufreq_driver imx_driver = {
.flags = CPUFREQ_STICKY,
.verify = imx_verify_speed,
.target = imx_set_target,
.get = imx_get_speed,
.init = imx_cpufreq_driver_init,
.name = "imx",
};
static int __init imx_cpufreq_init(void)
{
mpctl0_at_boot = 0;
if((CSCR & CSCR_MPEN) &&
((get_cr() & CR_920T_CLOCK_MODE) != CR_920T_FASTBUS_MODE))
mpctl0_at_boot = MPCTL0;
return cpufreq_register_driver(&imx_driver);
}
arch_initcall(imx_cpufreq_init);
|
