summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-pxa/cpu-pxa.c
blob: fb9ba1ab28269bddf4dc938f000f691bdaee1d29 (plain)
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
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
/*
 *  linux/arch/arm/mach-pxa/cpu-pxa.c
 *
 *  Copyright (C) 2002,2003 Intrinsyc Software
 *
 * 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
 *
 * History:
 *   31-Jul-2002 : Initial version [FB]
 *   29-Jan-2003 : added PXA255 support [FB]
 *   20-Apr-2003 : ported to v2.5 (Dustin McIntire, Sensoria Corp.)
 *
 * Note:
 *   This driver may change the memory bus clock rate, but will not do any
 *   platform specific access timing changes... for example if you have flash
 *   memory connected to CS0, you will need to register a platform specific
 *   notifier which will adjust the memory access strobes to maintain a
 *   minimum strobe width.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/cpufreq.h>

#include <asm/hardware.h>
#include <asm/arch/pxa-regs.h>
#include <asm/arch/pxa2xx-regs.h>

#ifdef DEBUG
static unsigned int freq_debug;
module_param(freq_debug, uint, 0);
MODULE_PARM_DESC(freq_debug, "Set the debug messages to on=1/off=0");
#else
#define freq_debug  0
#endif

static unsigned int pxa27x_maxfreq;
module_param(pxa27x_maxfreq, uint, 0);
MODULE_PARM_DESC(pxa27x_maxfreq, "Set the pxa27x maxfreq in MHz"
		 "(typically 624=>pxa270, 416=>pxa271, 520=>pxa272)");

typedef struct {
	unsigned int khz;
	unsigned int membus;
	unsigned int cccr;
	unsigned int div2;
	unsigned int cclkcfg;
} pxa_freqs_t;

/* Define the refresh period in mSec for the SDRAM and the number of rows */
#define SDRAM_TREF	64	/* standard 64ms SDRAM */
#define SDRAM_ROWS	4096	/* 64MB=8192 32MB=4096 */

#define CCLKCFG_TURBO		0x1
#define CCLKCFG_FCS		0x2
#define CCLKCFG_HALFTURBO	0x4
#define CCLKCFG_FASTBUS		0x8
#define MDREFR_DB2_MASK		(MDREFR_K2DB2 | MDREFR_K1DB2)
#define MDREFR_DRI_MASK		0xFFF

/*
 * PXA255 definitions
 */
/* Use the run mode frequencies for the CPUFREQ_POLICY_PERFORMANCE policy */
#define CCLKCFG			CCLKCFG_TURBO | CCLKCFG_FCS

static pxa_freqs_t pxa255_run_freqs[] =
{
	/* CPU   MEMBUS  CCCR  DIV2 CCLKCFG	   run  turbo PXbus SDRAM */
	{ 99500,  99500, 0x121, 1,  CCLKCFG},	/*  99,   99,   50,   50  */
	{132700, 132700, 0x123, 1,  CCLKCFG},	/* 133,  133,   66,   66  */
	{199100,  99500, 0x141, 0,  CCLKCFG},	/* 199,  199,   99,   99  */
	{265400, 132700, 0x143, 1,  CCLKCFG},	/* 265,  265,  133,   66  */
	{331800, 165900, 0x145, 1,  CCLKCFG},	/* 331,  331,  166,   83  */
	{398100,  99500, 0x161, 0,  CCLKCFG},	/* 398,  398,  196,   99  */
};

/* Use the turbo mode frequencies for the CPUFREQ_POLICY_POWERSAVE policy */
static pxa_freqs_t pxa255_turbo_freqs[] =
{
	/* CPU   MEMBUS  CCCR  DIV2 CCLKCFG	   run  turbo PXbus SDRAM */
	{ 99500, 99500,  0x121, 1,  CCLKCFG},	/*  99,   99,   50,   50  */
	{199100, 99500,  0x221, 0,  CCLKCFG},	/*  99,  199,   50,   99  */
	{298500, 99500,  0x321, 0,  CCLKCFG},	/*  99,  287,   50,   99  */
	{298600, 99500,  0x1c1, 0,  CCLKCFG},	/* 199,  287,   99,   99  */
	{398100, 99500,  0x241, 0,  CCLKCFG},	/* 199,  398,   99,   99  */
};

#define NUM_PXA25x_RUN_FREQS ARRAY_SIZE(pxa255_run_freqs)
#define NUM_PXA25x_TURBO_FREQS ARRAY_SIZE(pxa255_turbo_freqs)

static struct cpufreq_frequency_table
	pxa255_run_freq_table[NUM_PXA25x_RUN_FREQS+1];
static struct cpufreq_frequency_table
	pxa255_turbo_freq_table[NUM_PXA25x_TURBO_FREQS+1];

/*
 * PXA270 definitions
 *
 * For the PXA27x:
 * Control variables are A, L, 2N for CCCR; B, HT, T for CLKCFG.
 *
 * A = 0 => memory controller clock from table 3-7,
 * A = 1 => memory controller clock = system bus clock
 * Run mode frequency	= 13 MHz * L
 * Turbo mode frequency = 13 MHz * L * N
 * System bus frequency = 13 MHz * L / (B + 1)
 *
 * In CCCR:
 * A = 1
 * L = 16	  oscillator to run mode ratio
 * 2N = 6	  2 * (turbo mode to run mode ratio)
 *
 * In CCLKCFG:
 * B = 1	  Fast bus mode
 * HT = 0	  Half-Turbo mode
 * T = 1	  Turbo mode
 *
 * For now, just support some of the combinations in table 3-7 of
 * PXA27x Processor Family Developer's Manual to simplify frequency
 * change sequences.
 */
#define PXA27x_CCCR(A, L, N2) (A << 25 | N2 << 7 | L)
#define CCLKCFG2(B, HT, T) \
  (CCLKCFG_FCS | \
   ((B)  ? CCLKCFG_FASTBUS : 0) | \
   ((HT) ? CCLKCFG_HALFTURBO : 0) | \
   ((T)  ? CCLKCFG_TURBO : 0))

static pxa_freqs_t pxa27x_freqs[] = {
	{104000, 104000, PXA27x_CCCR(1,	 8, 2), 0, CCLKCFG2(1, 0, 1)},
	{156000, 104000, PXA27x_CCCR(1,	 8, 6), 0, CCLKCFG2(1, 1, 1)},
	{208000, 208000, PXA27x_CCCR(0, 16, 2), 1, CCLKCFG2(0, 0, 1)},
	{312000, 208000, PXA27x_CCCR(1, 16, 3), 1, CCLKCFG2(1, 0, 1)},
	{416000, 208000, PXA27x_CCCR(1, 16, 4), 1, CCLKCFG2(1, 0, 1)},
	{520000, 208000, PXA27x_CCCR(1, 16, 5), 1, CCLKCFG2(1, 0, 1)},
	{624000, 208000, PXA27x_CCCR(1, 16, 6), 1, CCLKCFG2(1, 0, 1)}
};

#define NUM_PXA27x_FREQS ARRAY_SIZE(pxa27x_freqs)
static struct cpufreq_frequency_table
	pxa27x_freq_table[NUM_PXA27x_FREQS+1];

extern unsigned get_clk_frequency_khz(int info);

static void find_freq_tables(struct cpufreq_policy *policy,
			     struct cpufreq_frequency_table **freq_table,
			     pxa_freqs_t **pxa_freqs)
{
	if (cpu_is_pxa25x()) {
		if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
			*pxa_freqs = pxa255_run_freqs;
			*freq_table = pxa255_run_freq_table;
		} else if (policy->policy == CPUFREQ_POLICY_POWERSAVE) {
			*pxa_freqs = pxa255_turbo_freqs;
			*freq_table = pxa255_turbo_freq_table;
		} else {
			printk("CPU PXA: Unknown policy found. "
			       "Using CPUFREQ_POLICY_PERFORMANCE\n");
			*pxa_freqs = pxa255_run_freqs;
			*freq_table = pxa255_run_freq_table;
		}
	}
	if (cpu_is_pxa27x()) {
		*pxa_freqs = pxa27x_freqs;
		*freq_table = pxa27x_freq_table;
	}
}

static void pxa27x_guess_max_freq(void)
{
	if (!pxa27x_maxfreq) {
		pxa27x_maxfreq = 416000;
		printk(KERN_INFO "PXA CPU 27x max frequency not defined "
		       "(pxa27x_maxfreq), assuming pxa271 with %dkHz maxfreq\n",
		       pxa27x_maxfreq);
	} else {
		pxa27x_maxfreq *= 1000;
	}
}

static u32 mdrefr_dri(unsigned int freq)
{
	u32 dri = 0;

	if (cpu_is_pxa25x())
		dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS * 32));
	if (cpu_is_pxa27x())
		dri = ((freq * SDRAM_TREF) / (SDRAM_ROWS - 31)) / 32;
	return dri;
}

/* find a valid frequency point */
static int pxa_verify_policy(struct cpufreq_policy *policy)
{
	struct cpufreq_frequency_table *pxa_freqs_table;
	pxa_freqs_t *pxa_freqs;
	int ret;

	find_freq_tables(policy, &pxa_freqs_table, &pxa_freqs);
	ret = cpufreq_frequency_table_verify(policy, pxa_freqs_table);

	if (freq_debug)
		pr_debug("Verified CPU policy: %dKhz min to %dKhz max\n",
			 policy->min, policy->max);

	return ret;
}

static unsigned int pxa_cpufreq_get(unsigned int cpu)
{
	return get_clk_frequency_khz(0);
}

static int pxa_set_target(struct cpufreq_policy *policy,
			  unsigned int target_freq,
			  unsigned int relation)
{
	struct cpufreq_frequency_table *pxa_freqs_table;
	pxa_freqs_t *pxa_freq_settings;
	struct cpufreq_freqs freqs;
	unsigned int idx;
	unsigned long flags;
	unsigned int new_freq_cpu, new_freq_mem;
	unsigned int unused, preset_mdrefr, postset_mdrefr, cclkcfg;

	/* Get the current policy */
	find_freq_tables(policy, &pxa_freqs_table, &pxa_freq_settings);

	/* Lookup the next frequency */
	if (cpufreq_frequency_table_target(policy, pxa_freqs_table,
					   target_freq, relation, &idx)) {
		return -EINVAL;
	}

	new_freq_cpu = pxa_freq_settings[idx].khz;
	new_freq_mem = pxa_freq_settings[idx].membus;
	freqs.old = policy->cur;
	freqs.new = new_freq_cpu;
	freqs.cpu = policy->cpu;

	if (freq_debug)
		pr_debug(KERN_INFO "Changing CPU frequency to %d Mhz, "
			 "(SDRAM %d Mhz)\n",
			 freqs.new / 1000, (pxa_freq_settings[idx].div2) ?
			 (new_freq_mem / 2000) : (new_freq_mem / 1000));

	/*
	 * Tell everyone what we're about to do...
	 * you should add a notify client with any platform specific
	 * Vcc changing capability
	 */
	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

	/* Calculate the next MDREFR.  If we're slowing down the SDRAM clock
	 * we need to preset the smaller DRI before the change.	 If we're
	 * speeding up we need to set the larger DRI value after the change.
	 */
	preset_mdrefr = postset_mdrefr = MDREFR;
	if ((MDREFR & MDREFR_DRI_MASK) > mdrefr_dri(new_freq_mem)) {
		preset_mdrefr = (preset_mdrefr & ~MDREFR_DRI_MASK);
		preset_mdrefr |= mdrefr_dri(new_freq_mem);
	}
	postset_mdrefr =
		(postset_mdrefr & ~MDREFR_DRI_MASK) | mdrefr_dri(new_freq_mem);

	/* If we're dividing the memory clock by two for the SDRAM clock, this
	 * must be set prior to the change.  Clearing the divide must be done
	 * after the change.
	 */
	if (pxa_freq_settings[idx].div2) {
		preset_mdrefr  |= MDREFR_DB2_MASK;
		postset_mdrefr |= MDREFR_DB2_MASK;
	} else {
		postset_mdrefr &= ~MDREFR_DB2_MASK;
	}

	local_irq_save(flags);

	/* Set new the CCCR and prepare CCLKCFG */
	CCCR = pxa_freq_settings[idx].cccr;
	cclkcfg = pxa_freq_settings[idx].cclkcfg;

	asm volatile("							\n\
		ldr	r4, [%1]		/* load MDREFR */	\n\
		b	2f						\n\
		.align	5						\n\
1:									\n\
		str	%3, [%1]		/* preset the MDREFR */	\n\
		mcr	p14, 0, %2, c6, c0, 0	/* set CCLKCFG[FCS] */	\n\
		str	%4, [%1]		/* postset the MDREFR */ \n\
									\n\
		b	3f						\n\
2:		b	1b						\n\
3:		nop							\n\
	  "
		     : "=&r" (unused)
		     : "r" (&MDREFR), "r" (cclkcfg),
		       "r" (preset_mdrefr), "r" (postset_mdrefr)
		     : "r4", "r5");
	local_irq_restore(flags);

	/*
	 * Tell everyone what we've just done...
	 * you should add a notify client with any platform specific
	 * SDRAM refresh timer adjustments
	 */
	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

	return 0;
}

static __init int pxa_cpufreq_init(struct cpufreq_policy *policy)
{
	int i;
	unsigned int freq;

	/* try to guess pxa27x cpu */
	if (cpu_is_pxa27x())
		pxa27x_guess_max_freq();

	/* set default policy and cpuinfo */
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	if (cpu_is_pxa25x())
		policy->policy = CPUFREQ_POLICY_PERFORMANCE;
	policy->cpuinfo.transition_latency = 1000; /* FIXME: 1 ms, assumed */
	policy->cur = get_clk_frequency_khz(0);	   /* current freq */
	policy->min = policy->max = policy->cur;

	/* Generate pxa25x the run cpufreq_frequency_table struct */
	for (i = 0; i < NUM_PXA25x_RUN_FREQS; i++) {
		pxa255_run_freq_table[i].frequency = pxa255_run_freqs[i].khz;
		pxa255_run_freq_table[i].index = i;
	}
	pxa255_run_freq_table[i].frequency = CPUFREQ_TABLE_END;

	/* Generate pxa25x the turbo cpufreq_frequency_table struct */
	for (i = 0; i < NUM_PXA25x_TURBO_FREQS; i++) {
		pxa255_turbo_freq_table[i].frequency =
			pxa255_turbo_freqs[i].khz;
		pxa255_turbo_freq_table[i].index = i;
	}
	pxa255_turbo_freq_table[i].frequency = CPUFREQ_TABLE_END;

	/* Generate the pxa27x cpufreq_frequency_table struct */
	for (i = 0; i < NUM_PXA27x_FREQS; i++) {
		freq = pxa27x_freqs[i].khz;
		if (freq > pxa27x_maxfreq)
			break;
		pxa27x_freq_table[i].frequency = freq;
		pxa27x_freq_table[i].index = i;
	}
	pxa27x_freq_table[i].frequency = CPUFREQ_TABLE_END;

	/*
	 * Set the policy's minimum and maximum frequencies from the tables
	 * just constructed.  This sets cpuinfo.mxx_freq, min and max.
	 */
	if (cpu_is_pxa25x())
		cpufreq_frequency_table_cpuinfo(policy, pxa255_run_freq_table);
	else if (cpu_is_pxa27x())
		cpufreq_frequency_table_cpuinfo(policy, pxa27x_freq_table);

	printk(KERN_INFO "PXA CPU frequency change support initialized\n");

	return 0;
}

static struct cpufreq_driver pxa_cpufreq_driver = {
	.verify	= pxa_verify_policy,
	.target	= pxa_set_target,
	.init	= pxa_cpufreq_init,
	.get	= pxa_cpufreq_get,
	.name	= "PXA2xx",
};

static int __init pxa_cpu_init(void)
{
	int ret = -ENODEV;
	if (cpu_is_pxa25x() || cpu_is_pxa27x())
		ret = cpufreq_register_driver(&pxa_cpufreq_driver);
	return ret;
}

static void __exit pxa_cpu_exit(void)
{
	cpufreq_unregister_driver(&pxa_cpufreq_driver);
}


MODULE_AUTHOR("Intrinsyc Software Inc.");
MODULE_DESCRIPTION("CPU frequency changing driver for the PXA architecture");
MODULE_LICENSE("GPL");
module_init(pxa_cpu_init);
module_exit(pxa_cpu_exit);
OpenPOWER on IntegriCloud