aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/cpu/cpufreq/gx-suspmod.c
blob: 1a49adb1f4a68c41798583c4232d480f6a523376 (plain) (blame)
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
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
/*
 *	Cyrix MediaGX and NatSemi Geode Suspend Modulation
 *	(C) 2002 Zwane Mwaikambo <zwane@commfireservices.com>
 *	(C) 2002 Hiroshi Miura   <miura@da-cha.org>
 *	All Rights Reserved
 *
 *	This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      version 2 as published by the Free Software Foundation 
 *
 *      The author(s) of this software shall not be held liable for damages
 *      of any nature resulting due to the use of this software. This
 *      software is provided AS-IS with no warranties.
 *	
 * Theoritical note:
 *
 *	(see Geode(tm) CS5530 manual (rev.4.1) page.56)
 *
 *	CPU frequency control on NatSemi Geode GX1/GXLV processor and CS55x0
 *	are based on Suspend Moduration.
 *
 *	Suspend Modulation works by asserting and de-asserting the SUSP# pin
 *	to CPU(GX1/GXLV) for configurable durations. When asserting SUSP#
 *	the CPU enters an idle state. GX1 stops its core clock when SUSP# is 
 *	asserted then power consumption is reduced.
 *
 *	Suspend Modulation's OFF/ON duration are configurable 
 *	with 'Suspend Modulation OFF Count Register'
 *	and 'Suspend Modulation ON Count Register'.
 *	These registers are 8bit counters that represent the number of 
 *	32us intervals which the SUSP# pin is asserted(ON)/de-asserted(OFF)
 *	to the processor.
 *
 *	These counters define a ratio which is the effective frequency 
 * 	of operation of the system.
 *
 *			       OFF Count
 *	F_eff = Fgx * ----------------------
 *	                OFF Count + ON Count
 *
 *	0 <= On Count, Off Count <= 255
 *
 *	From these limits, we can get register values 
 *
 *	off_duration + on_duration <= MAX_DURATION
 *	on_duration = off_duration * (stock_freq - freq) / freq
 *
 *      off_duration  =  (freq * DURATION) / stock_freq 
 *      on_duration = DURATION - off_duration 
 *
 *
 *---------------------------------------------------------------------------
 *
 * ChangeLog:
 *  	Dec. 12, 2003	Hiroshi Miura <miura@da-cha.org>
 *  		- fix on/off register mistake
 *  		- fix cpu_khz calc when it stops cpu modulation.
 *
 *	Dec. 11, 2002 	Hiroshi Miura <miura@da-cha.org>
 *		- rewrite for Cyrix MediaGX Cx5510/5520 and 
 *		  NatSemi Geode Cs5530(A).
 *
 *	Jul. ??, 2002  Zwane Mwaikambo <zwane@commfireservices.com>
 *		- cs5530_mod patch for 2.4.19-rc1.
 *
 *---------------------------------------------------------------------------
 *
 * Todo
 *	Test on machines with 5510, 5530, 5530A
 */

/************************************************************************
 *			Suspend Modulation - Definitions		*
 ************************************************************************/

#include <linux/kernel.h>
#include <linux/module.h> 
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpufreq.h>
#include <linux/pci.h>
#include <asm/processor.h> 
#include <asm/errno.h>

/* PCI config registers, all at F0 */
#define PCI_PMER1              0x80    /* power management enable register 1 */
#define PCI_PMER2              0x81    /* power management enable register 2 */
#define PCI_PMER3              0x82    /* power management enable register 3 */
#define PCI_IRQTC              0x8c    /* irq speedup timer counter register:typical 2 to 4ms */
#define PCI_VIDTC              0x8d    /* video speedup timer counter register: typical 50 to 100ms */
#define PCI_MODOFF             0x94    /* suspend modulation OFF counter register, 1 = 32us */
#define PCI_MODON              0x95    /* suspend modulation ON counter register */
#define PCI_SUSCFG             0x96    /* suspend configuration register */

/* PMER1 bits */
#define GPM                    (1<<0)  /* global power management */
#define GIT                    (1<<1)  /* globally enable PM device idle timers */
#define GTR                    (1<<2)  /* globally enable IO traps */
#define IRQ_SPDUP              (1<<3)  /* disable clock throttle during interrupt handling */
#define VID_SPDUP              (1<<4)  /* disable clock throttle during vga video handling */

/* SUSCFG bits */
#define SUSMOD                 (1<<0)  /* enable/disable suspend modulation */
/* the belows support only with cs5530 (after rev.1.2)/cs5530A */ 
#define SMISPDUP               (1<<1)  /* select how SMI re-enable suspend modulation: */
                                       /* IRQTC timer or read SMI speedup disable reg.(F1BAR[08-09h]) */
#define SUSCFG                 (1<<2)  /* enable powering down a GXLV processor. "Special 3Volt Suspend" mode */
/* the belows support only with cs5530A */ 
#define PWRSVE_ISA             (1<<3)  /* stop ISA clock  */
#define PWRSVE                 (1<<4)  /* active idle */

struct gxfreq_params {
	u8 on_duration;
	u8 off_duration;
	u8 pci_suscfg;
	u8 pci_pmer1;
	u8 pci_pmer2;
	u8 pci_rev;
	struct pci_dev *cs55x0;
};

static struct gxfreq_params *gx_params;
static int stock_freq;

/* PCI bus clock - defaults to 30.000 if cpu_khz is not available */
static int pci_busclk = 0;
module_param (pci_busclk, int, 0444);

/* maximum duration for which the cpu may be suspended
 * (32us * MAX_DURATION). If no parameter is given, this defaults
 * to 255. 
 * Note that this leads to a maximum of 8 ms(!) where the CPU clock
 * is suspended -- processing power is just 0.39% of what it used to be,
 * though. 781.25 kHz(!) for a 200 MHz processor -- wow. */
static int max_duration = 255;
module_param (max_duration, int, 0444);

/* For the default policy, we want at least some processing power
 * - let's say 5%. (min = maxfreq / POLICY_MIN_DIV)
 */
#define POLICY_MIN_DIV 20


#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "gx-suspmod", msg)

/**
 *      we can detect a core multipiler from dir0_lsb 
 *      from GX1 datasheet p.56, 
 *	   MULT[3:0]:
 *	   0000 = SYSCLK multiplied by 4 (test only)
 *	   0001 = SYSCLK multiplied by 10
 *	   0010 = SYSCLK multiplied by 4
 *	   0011 = SYSCLK multiplied by 6
 *	   0100 = SYSCLK multiplied by 9
 *	   0101 = SYSCLK multiplied by 5
 *	   0110 = SYSCLK multiplied by 7
 *	   0111 = SYSCLK multiplied by 8
 *              of 33.3MHz
 **/
static int gx_freq_mult[16] = {
		4, 10, 4, 6, 9, 5, 7, 8,
		0, 0, 0, 0, 0, 0, 0, 0
};


/****************************************************************
 * 	Low Level chipset interface				*
 ****************************************************************/
static struct pci_device_id gx_chipset_tbl[] __initdata = {
        { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5530_LEGACY, PCI_ANY_ID, PCI_ANY_ID },
        { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5520, PCI_ANY_ID, PCI_ANY_ID },
        { PCI_VENDOR_ID_CYRIX, PCI_DEVICE_ID_CYRIX_5510, PCI_ANY_ID, PCI_ANY_ID },
        { 0, },
};

/**
 *     gx_detect_chipset:
 *
 **/
static __init struct pci_dev *gx_detect_chipset(void)
{
	struct pci_dev *gx_pci = NULL;

	/* check if CPU is a MediaGX or a Geode. */
        if ((current_cpu_data.x86_vendor != X86_VENDOR_NSC) && 
	    (current_cpu_data.x86_vendor != X86_VENDOR_CYRIX)) {
		dprintk("error: no MediaGX/Geode processor found!\n");
		return NULL;		
	}

	/* detect which companion chip is used */
	while ((gx_pci = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, gx_pci)) != NULL) {
		if ((pci_match_device (gx_chipset_tbl, gx_pci)) != NULL) {
			return gx_pci;
		}
	}

	dprintk("error: no supported chipset found!\n");
	return NULL;
}

/**
 *      gx_get_cpuspeed:
 *
 * Finds out at which efficient frequency the Cyrix MediaGX/NatSemi Geode CPU runs.
 */
static unsigned int gx_get_cpuspeed(unsigned int cpu)
{
	if ((gx_params->pci_suscfg & SUSMOD) == 0) 
		return stock_freq;

	return (stock_freq * gx_params->off_duration) 
		/ (gx_params->on_duration + gx_params->off_duration);
}

/**
 *      gx_validate_speed:
 *      determine current cpu speed
 *       
**/

static unsigned int gx_validate_speed(unsigned int khz, u8 *on_duration, u8 *off_duration)
{
	unsigned int i;
	u8 tmp_on, tmp_off;
	int old_tmp_freq = stock_freq;
	int tmp_freq;

	*off_duration=1;
	*on_duration=0;

	for (i=max_duration; i>0; i--) {
		tmp_off = ((khz * i) / stock_freq) & 0xff; 
		tmp_on = i - tmp_off;
		tmp_freq = (stock_freq * tmp_off) / i;
		/* if this relation is closer to khz, use this. If it's equal,
		 * prefer it, too - lower latency */
		if (abs(tmp_freq - khz) <= abs(old_tmp_freq - khz)) {
			*on_duration = tmp_on;
			*off_duration = tmp_off;
			old_tmp_freq = tmp_freq;
		}
	}

	return old_tmp_freq;
}


/**
 * 	gx_set_cpuspeed:
 *		set cpu speed in khz.
 **/

static void gx_set_cpuspeed(unsigned int khz)
{
        u8 suscfg, pmer1;
	unsigned int new_khz;
	unsigned long flags;
	struct cpufreq_freqs freqs;


	freqs.cpu = 0;
	freqs.old = gx_get_cpuspeed(0);

	new_khz = gx_validate_speed(khz, &gx_params->on_duration, &gx_params->off_duration);

	freqs.new = new_khz;

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	local_irq_save(flags);

	if (new_khz != stock_freq) {  /* if new khz == 100% of CPU speed, it is special case */
		switch (gx_params->cs55x0->device) {
		case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
			pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
			/* FIXME: need to test other values -- Zwane,Miura */
			pci_write_config_byte(gx_params->cs55x0, PCI_IRQTC, 4); /* typical 2 to 4ms */
			pci_write_config_byte(gx_params->cs55x0, PCI_VIDTC, 100);/* typical 50 to 100ms */
			pci_write_config_byte(gx_params->cs55x0, PCI_PMER1, pmer1);

			if (gx_params->pci_rev < 0x10) {   /* CS5530(rev 1.2, 1.3) */
				suscfg = gx_params->pci_suscfg | SUSMOD;
			} else {                           /* CS5530A,B.. */
				suscfg = gx_params->pci_suscfg | SUSMOD | PWRSVE;
			}
			break;
		case PCI_DEVICE_ID_CYRIX_5520:
		case PCI_DEVICE_ID_CYRIX_5510:
			suscfg = gx_params->pci_suscfg | SUSMOD;
			break;
		default:
			local_irq_restore(flags);
			dprintk("fatal: try to set unknown chipset.\n");
			return;
		}
	} else {
		suscfg = gx_params->pci_suscfg & ~(SUSMOD);
		gx_params->off_duration = 0;
		gx_params->on_duration = 0;
		dprintk("suspend modulation disabled: cpu runs 100 percent speed.\n");
	}

	pci_write_config_byte(gx_params->cs55x0, PCI_MODOFF, gx_params->off_duration);
	pci_write_config_byte(gx_params->cs55x0, PCI_MODON, gx_params->on_duration);

        pci_write_config_byte(gx_params->cs55x0, PCI_SUSCFG, suscfg);
        pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);

        local_irq_restore(flags);

	gx_params->pci_suscfg = suscfg;

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

        dprintk("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
                gx_params->on_duration * 32, gx_params->off_duration * 32);
	dprintk("suspend modulation w/ clock speed: %d kHz.\n", freqs.new); 
}

/****************************************************************
 *             High level functions                             *
 ****************************************************************/

/*
 *	cpufreq_gx_verify: test if frequency range is valid 
 *
 *	This function checks if a given frequency range in kHz is valid 
 *      for the hardware supported by the driver. 
 */

static int cpufreq_gx_verify(struct cpufreq_policy *policy)
{
	unsigned int tmp_freq = 0;
	u8 tmp1, tmp2;

        if (!stock_freq || !policy)
                return -EINVAL;

	policy->cpu = 0;
	cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);

	/* it needs to be assured that at least one supported frequency is
	 * within policy->min and policy->max. If it is not, policy->max
	 * needs to be increased until one freuqency is supported.
	 * policy->min may not be decreased, though. This way we guarantee a 
	 * specific processing capacity.
	 */
	tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
	if (tmp_freq < policy->min) 
		tmp_freq += stock_freq / max_duration;
	policy->min = tmp_freq;
	if (policy->min > policy->max) 
		policy->max = tmp_freq;
	tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
	if (tmp_freq > policy->max)
		tmp_freq -= stock_freq / max_duration;
	policy->max = tmp_freq;
	if (policy->max < policy->min)
		policy->max = policy->min;
	cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);
	
	return 0;
}

/*
 *      cpufreq_gx_target:  
 *
 */
static int cpufreq_gx_target(struct cpufreq_policy *policy,
			     unsigned int target_freq,
			     unsigned int relation)
{
	u8 tmp1, tmp2;
	unsigned int tmp_freq;

        if (!stock_freq || !policy)
                return -EINVAL;

	policy->cpu = 0;

	tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
	while (tmp_freq < policy->min) {
		tmp_freq += stock_freq / max_duration;
		tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
	}
	while (tmp_freq > policy->max) {
		tmp_freq -= stock_freq / max_duration;
		tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
	}

	gx_set_cpuspeed(tmp_freq);

	return 0;
}

static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
{
	unsigned int maxfreq, curfreq;

	if (!policy || policy->cpu != 0)
		return -ENODEV;

	/* determine maximum frequency */
	if (pci_busclk) {
		maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
	} else if (cpu_khz) {
		maxfreq = cpu_khz;
	} else {
		maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
	}
	stock_freq = maxfreq;
	curfreq = gx_get_cpuspeed(0);

	dprintk("cpu max frequency is %d.\n", maxfreq);
	dprintk("cpu current frequency is %dkHz.\n",curfreq);

	/* setup basic struct for cpufreq API */
	policy->cpu = 0;

	if (max_duration < POLICY_MIN_DIV)
		policy->min = maxfreq / max_duration;
	else
		policy->min = maxfreq / POLICY_MIN_DIV;
	policy->max = maxfreq;
	policy->cur = curfreq;
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	policy->cpuinfo.min_freq = maxfreq / max_duration;
	policy->cpuinfo.max_freq = maxfreq;
	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

	return 0;
}

/* 
 * cpufreq_gx_init:
 *   MediaGX/Geode GX initialize cpufreq driver
 */
static struct cpufreq_driver gx_suspmod_driver = {
	.get		= gx_get_cpuspeed,
	.verify		= cpufreq_gx_verify,
	.target		= cpufreq_gx_target,
	.init		= cpufreq_gx_cpu_init,
	.name		= "gx-suspmod",
	.owner		= THIS_MODULE,
};

static int __init cpufreq_gx_init(void)
{
	int ret;
	struct gxfreq_params *params;
	struct pci_dev *gx_pci;
	u32 class_rev;

	/* Test if we have the right hardware */
	if ((gx_pci = gx_detect_chipset()) == NULL) 
		return -ENODEV;

	/* check whether module parameters are sane */
	if (max_duration > 0xff)
		max_duration = 0xff;

	dprintk("geode suspend modulation available.\n");

	params = kmalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
	if (params == NULL)
		return -ENOMEM;
	memset(params, 0, sizeof(struct gxfreq_params));

	params->cs55x0 = gx_pci;
	gx_params = params;

	/* keep cs55x0 configurations */
	pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
	pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
	pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
	pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
	pci_read_config_byte(params->cs55x0, PCI_MODOFF, &(params->off_duration));
        pci_read_config_dword(params->cs55x0, PCI_CLASS_REVISION, &class_rev);
	params->pci_rev = class_rev && 0xff;

	if ((ret = cpufreq_register_driver(&gx_suspmod_driver))) { 
		kfree(params);
		return ret;                   /* register error! */
	}

	return 0;
}

static void __exit cpufreq_gx_exit(void)
{
	cpufreq_unregister_driver(&gx_suspmod_driver);
	pci_dev_put(gx_params->cs55x0);
	kfree(gx_params);
}

MODULE_AUTHOR ("Hiroshi Miura <miura@da-cha.org>");
MODULE_DESCRIPTION ("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
MODULE_LICENSE ("GPL");

module_init(cpufreq_gx_init);
module_exit(cpufreq_gx_exit);