2 * linux/arch/arm/mach-pxa/cpufreq-pxa2xx.c
4 * Copyright (C) 2002,2003 Intrinsyc Software
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21 * 31-Jul-2002 : Initial version [FB]
22 * 29-Jan-2003 : added PXA255 support [FB]
23 * 20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
26 * This driver may change the memory bus clock rate, but will not do any
27 * platform specific access timing changes... for example if you have flash
28 * memory connected to CS0, you will need to register a platform specific
29 * notifier which will adjust the memory access strobes to maintain a
30 * minimum strobe width.
34 #include <linux/kernel.h>
35 #include <linux/module.h>
36 #include <linux/sched.h>
37 #include <linux/init.h>
38 #include <linux/cpufreq.h>
40 #include <mach/pxa2xx-regs.h>
43 static unsigned int freq_debug
;
44 module_param(freq_debug
, uint
, 0);
45 MODULE_PARM_DESC(freq_debug
, "Set the debug messages to on=1/off=0");
50 static unsigned int pxa27x_maxfreq
;
51 module_param(pxa27x_maxfreq
, uint
, 0);
52 MODULE_PARM_DESC(pxa27x_maxfreq
, "Set the pxa27x maxfreq in MHz"
53 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");
63 /* Define the refresh period in mSec for the SDRAM and the number of rows */
64 #define SDRAM_TREF 64 /* standard 64ms SDRAM */
65 static unsigned int sdram_rows
;
67 #define CCLKCFG_TURBO 0x1
68 #define CCLKCFG_FCS 0x2
69 #define CCLKCFG_HALFTURBO 0x4
70 #define CCLKCFG_FASTBUS 0x8
71 #define MDREFR_DB2_MASK (MDREFR_K2DB2 | MDREFR_K1DB2)
72 #define MDREFR_DRI_MASK 0xFFF
74 #define MDCNFG_DRAC2(mdcnfg) (((mdcnfg) >> 21) & 0x3)
75 #define MDCNFG_DRAC0(mdcnfg) (((mdcnfg) >> 5) & 0x3)
80 /* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */
81 #define CCLKCFG CCLKCFG_TURBO | CCLKCFG_FCS
83 static pxa_freqs_t pxa255_run_freqs
[] =
85 /* CPU MEMBUS CCCR DIV2 CCLKCFG run turbo PXbus SDRAM */
86 { 99500, 99500, 0x121, 1, CCLKCFG
}, /* 99, 99, 50, 50 */
87 {132700, 132700, 0x123, 1, CCLKCFG
}, /* 133, 133, 66, 66 */
88 {199100, 99500, 0x141, 0, CCLKCFG
}, /* 199, 199, 99, 99 */
89 {265400, 132700, 0x143, 1, CCLKCFG
}, /* 265, 265, 133, 66 */
90 {331800, 165900, 0x145, 1, CCLKCFG
}, /* 331, 331, 166, 83 */
91 {398100, 99500, 0x161, 0, CCLKCFG
}, /* 398, 398, 196, 99 */
94 /* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
95 static pxa_freqs_t pxa255_turbo_freqs
[] =
97 /* CPU MEMBUS CCCR DIV2 CCLKCFG run turbo PXbus SDRAM */
98 { 99500, 99500, 0x121, 1, CCLKCFG
}, /* 99, 99, 50, 50 */
99 {199100, 99500, 0x221, 0, CCLKCFG
}, /* 99, 199, 50, 99 */
100 {298500, 99500, 0x321, 0, CCLKCFG
}, /* 99, 287, 50, 99 */
101 {298600, 99500, 0x1c1, 0, CCLKCFG
}, /* 199, 287, 99, 99 */
102 {398100, 99500, 0x241, 0, CCLKCFG
}, /* 199, 398, 99, 99 */
105 #define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
106 #define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)
108 static struct cpufreq_frequency_table
109 pxa255_run_freq_table
[NUM_PXA25x_RUN_FREQS
+1];
110 static struct cpufreq_frequency_table
111 pxa255_turbo_freq_table
[NUM_PXA25x_TURBO_FREQS
+1];
113 static unsigned int pxa255_turbo_table
;
114 module_param(pxa255_turbo_table
, uint
, 0);
115 MODULE_PARM_DESC(pxa255_turbo_table
, "Selects the frequency table (0 = run table, !0 = turbo table)");
121 * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
123 * A = 0 => memory controller clock from table 3-7,
124 * A = 1 => memory controller clock = system bus clock
125 * Run mode frequency = 13 MHz * L
126 * Turbo mode frequency = 13 MHz * L * N
127 * System bus frequency = 13 MHz * L / (B + 1)
131 * L = 16 oscillator to run mode ratio
132 * 2N = 6 2 * (turbo mode to run mode ratio)
135 * B = 1 Fast bus mode
136 * HT = 0 Half-Turbo mode
139 * For now, just support some of the combinations in table 3-7 of
140 * PXA27x Processor Family Developer's Manual to simplify frequency
143 #define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
144 #define CCLKCFG2(B, HT, T) \
146 ((B) ? CCLKCFG_FASTBUS : 0) | \
147 ((HT) ? CCLKCFG_HALFTURBO : 0) | \
148 ((T) ? CCLKCFG_TURBO : 0))
150 static pxa_freqs_t pxa27x_freqs
[] = {
151 {104000, 104000, PXA27x_CCCR(1, 8, 2), 0, CCLKCFG2(1, 0, 1)},
152 {156000, 104000, PXA27x_CCCR(1, 8, 6), 0, CCLKCFG2(1, 1, 1)},
153 {208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1)},
154 {312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1)},
155 {416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1)},
156 {520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1)},
157 {624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1)}
160 #define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
161 static struct cpufreq_frequency_table
162 pxa27x_freq_table
[NUM_PXA27x_FREQS
+1];
164 extern unsigned get_clk_frequency_khz(int info
);
166 static void find_freq_tables(struct cpufreq_frequency_table
**freq_table
,
167 pxa_freqs_t
**pxa_freqs
)
169 if (cpu_is_pxa25x()) {
170 if (!pxa255_turbo_table
) {
171 *pxa_freqs
= pxa255_run_freqs
;
172 *freq_table
= pxa255_run_freq_table
;
174 *pxa_freqs
= pxa255_turbo_freqs
;
175 *freq_table
= pxa255_turbo_freq_table
;
178 if (cpu_is_pxa27x()) {
179 *pxa_freqs
= pxa27x_freqs
;
180 *freq_table
= pxa27x_freq_table
;
184 static void pxa27x_guess_max_freq(void)
186 if (!pxa27x_maxfreq
) {
187 pxa27x_maxfreq
= 416000;
188 printk(KERN_INFO
"PXA CPU 27x max frequency not defined "
189 "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
192 pxa27x_maxfreq
*= 1000;
196 static void init_sdram_rows(void)
198 uint32_t mdcnfg
= MDCNFG
;
199 unsigned int drac2
= 0, drac0
= 0;
201 if (mdcnfg
& (MDCNFG_DE2
| MDCNFG_DE3
))
202 drac2
= MDCNFG_DRAC2(mdcnfg
);
204 if (mdcnfg
& (MDCNFG_DE0
| MDCNFG_DE1
))
205 drac0
= MDCNFG_DRAC0(mdcnfg
);
207 sdram_rows
= 1 << (11 + max(drac0
, drac2
));
210 static u32
mdrefr_dri(unsigned int freq
)
215 dri
= ((freq
* SDRAM_TREF
) / (sdram_rows
* 32));
217 dri
= ((freq
* SDRAM_TREF
) / (sdram_rows
- 31)) / 32;
221 /* find a valid frequency point */
222 static int pxa_verify_policy(struct cpufreq_policy
*policy
)
224 struct cpufreq_frequency_table
*pxa_freqs_table
;
225 pxa_freqs_t
*pxa_freqs
;
228 find_freq_tables(&pxa_freqs_table
, &pxa_freqs
);
229 ret
= cpufreq_frequency_table_verify(policy
, pxa_freqs_table
);
232 pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n",
233 policy
->min
, policy
->max
);
238 static unsigned int pxa_cpufreq_get(unsigned int cpu
)
240 return get_clk_frequency_khz(0);
243 static int pxa_set_target(struct cpufreq_policy
*policy
,
244 unsigned int target_freq
,
245 unsigned int relation
)
247 struct cpufreq_frequency_table
*pxa_freqs_table
;
248 pxa_freqs_t
*pxa_freq_settings
;
249 struct cpufreq_freqs freqs
;
252 unsigned int new_freq_cpu
, new_freq_mem
;
253 unsigned int unused
, preset_mdrefr
, postset_mdrefr
, cclkcfg
;
255 /* Get the current policy */
256 find_freq_tables(&pxa_freqs_table
, &pxa_freq_settings
);
258 /* Lookup the next frequency */
259 if (cpufreq_frequency_table_target(policy
, pxa_freqs_table
,
260 target_freq
, relation
, &idx
)) {
264 new_freq_cpu
= pxa_freq_settings
[idx
].khz
;
265 new_freq_mem
= pxa_freq_settings
[idx
].membus
;
266 freqs
.old
= policy
->cur
;
267 freqs
.new = new_freq_cpu
;
268 freqs
.cpu
= policy
->cpu
;
271 pr_debug(KERN_INFO
"Changing CPU frequency to %d Mhz, "
273 freqs
.new / 1000, (pxa_freq_settings
[idx
].div2
) ?
274 (new_freq_mem
/ 2000) : (new_freq_mem
/ 1000));
277 * Tell everyone what we're about to do...
278 * you should add a notify client with any platform specific
279 * Vcc changing capability
281 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
283 /* Calculate the next MDREFR. If we're slowing down the SDRAM clock
284 * we need to preset the smaller DRI before the change. If we're
285 * speeding up we need to set the larger DRI value after the change.
287 preset_mdrefr
= postset_mdrefr
= MDREFR
;
288 if ((MDREFR
& MDREFR_DRI_MASK
) > mdrefr_dri(new_freq_mem
)) {
289 preset_mdrefr
= (preset_mdrefr
& ~MDREFR_DRI_MASK
);
290 preset_mdrefr
|= mdrefr_dri(new_freq_mem
);
293 (postset_mdrefr
& ~MDREFR_DRI_MASK
) | mdrefr_dri(new_freq_mem
);
295 /* If we're dividing the memory clock by two for the SDRAM clock, this
296 * must be set prior to the change. Clearing the divide must be done
299 if (pxa_freq_settings
[idx
].div2
) {
300 preset_mdrefr
|= MDREFR_DB2_MASK
;
301 postset_mdrefr
|= MDREFR_DB2_MASK
;
303 postset_mdrefr
&= ~MDREFR_DB2_MASK
;
306 local_irq_save(flags
);
308 /* Set new the CCCR and prepare CCLKCFG */
309 CCCR
= pxa_freq_settings
[idx
].cccr
;
310 cclkcfg
= pxa_freq_settings
[idx
].cclkcfg
;
313 ldr r4, [%1] /* load MDREFR */ \n\
317 str %3, [%1] /* preset the MDREFR */ \n\
318 mcr p14, 0, %2, c6, c0, 0 /* set CCLKCFG[FCS] */ \n\
319 str %4, [%1] /* postset the MDREFR */ \n\
326 : "r" (&MDREFR
), "r" (cclkcfg
),
327 "r" (preset_mdrefr
), "r" (postset_mdrefr
)
329 local_irq_restore(flags
);
332 * Tell everyone what we've just done...
333 * you should add a notify client with any platform specific
334 * SDRAM refresh timer adjustments
336 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
341 static __init
int pxa_cpufreq_init(struct cpufreq_policy
*policy
)
345 struct cpufreq_frequency_table
*pxa255_freq_table
;
346 pxa_freqs_t
*pxa255_freqs
;
348 /* try to guess pxa27x cpu */
350 pxa27x_guess_max_freq();
354 /* set default policy and cpuinfo */
355 policy
->cpuinfo
.transition_latency
= 1000; /* FIXME: 1 ms, assumed */
356 policy
->cur
= get_clk_frequency_khz(0); /* current freq */
357 policy
->min
= policy
->max
= policy
->cur
;
359 /* Generate pxa25x the run cpufreq_frequency_table struct */
360 for (i
= 0; i
< NUM_PXA25x_RUN_FREQS
; i
++) {
361 pxa255_run_freq_table
[i
].frequency
= pxa255_run_freqs
[i
].khz
;
362 pxa255_run_freq_table
[i
].index
= i
;
364 pxa255_run_freq_table
[i
].frequency
= CPUFREQ_TABLE_END
;
366 /* Generate pxa25x the turbo cpufreq_frequency_table struct */
367 for (i
= 0; i
< NUM_PXA25x_TURBO_FREQS
; i
++) {
368 pxa255_turbo_freq_table
[i
].frequency
=
369 pxa255_turbo_freqs
[i
].khz
;
370 pxa255_turbo_freq_table
[i
].index
= i
;
372 pxa255_turbo_freq_table
[i
].frequency
= CPUFREQ_TABLE_END
;
374 pxa255_turbo_table
= !!pxa255_turbo_table
;
376 /* Generate the pxa27x cpufreq_frequency_table struct */
377 for (i
= 0; i
< NUM_PXA27x_FREQS
; i
++) {
378 freq
= pxa27x_freqs
[i
].khz
;
379 if (freq
> pxa27x_maxfreq
)
381 pxa27x_freq_table
[i
].frequency
= freq
;
382 pxa27x_freq_table
[i
].index
= i
;
384 pxa27x_freq_table
[i
].frequency
= CPUFREQ_TABLE_END
;
387 * Set the policy's minimum and maximum frequencies from the tables
388 * just constructed. This sets cpuinfo.mxx_freq, min and max.
390 if (cpu_is_pxa25x()) {
391 find_freq_tables(&pxa255_freq_table
, &pxa255_freqs
);
392 pr_info("PXA255 cpufreq using %s frequency table\n",
393 pxa255_turbo_table
? "turbo" : "run");
394 cpufreq_frequency_table_cpuinfo(policy
, pxa255_freq_table
);
396 else if (cpu_is_pxa27x())
397 cpufreq_frequency_table_cpuinfo(policy
, pxa27x_freq_table
);
399 printk(KERN_INFO
"PXA CPU frequency change support initialized\n");
404 static struct cpufreq_driver pxa_cpufreq_driver
= {
405 .verify
= pxa_verify_policy
,
406 .target
= pxa_set_target
,
407 .init
= pxa_cpufreq_init
,
408 .get
= pxa_cpufreq_get
,
412 static int __init
pxa_cpu_init(void)
415 if (cpu_is_pxa25x() || cpu_is_pxa27x())
416 ret
= cpufreq_register_driver(&pxa_cpufreq_driver
);
420 static void __exit
pxa_cpu_exit(void)
422 cpufreq_unregister_driver(&pxa_cpufreq_driver
);
426 MODULE_AUTHOR("Intrinsyc Software Inc.");
427 MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
428 MODULE_LICENSE("GPL");
429 module_init(pxa_cpu_init
);
430 module_exit(pxa_cpu_exit
);