summaryrefslogtreecommitdiffstats
path: root/sys/dev/acpica/acpi_throttle.c
blob: 40476e02bd984efecda8e2dd9c6b6f6e4a5566df (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
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
/*-
 * Copyright (c) 2003-2005 Nate Lawson (SDG)
 * Copyright (c) 2001 Michael Smith
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *	notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *	notice, this list of conditions and the following disclaimer in the
 *	documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>

#include <machine/bus.h>

#include <contrib/dev/acpica/include/acpi.h>

#include <dev/acpica/acpivar.h>
#include <dev/pci/pcivar.h>

#include "cpufreq_if.h"

/*
 * Throttling provides relative frequency control.  It involves modulating
 * the clock so that the CPU is active for only a fraction of the normal
 * clock cycle.  It does not change voltage and so is less efficient than
 * other mechanisms.  Since it is relative, it can be used in addition to
 * absolute cpufreq drivers.  We support the ACPI 2.0 specification.
 */

struct acpi_throttle_softc {
	device_t	 cpu_dev;
	ACPI_HANDLE	 cpu_handle;
	uint32_t	 cpu_p_blk;	/* ACPI P_BLK location */
	uint32_t	 cpu_p_blk_len;	/* P_BLK length (must be 6). */
	struct resource	*cpu_p_cnt;	/* Throttling control register */
	int		 cpu_p_type;	/* Resource type for cpu_p_cnt. */
	uint32_t	 cpu_thr_state;	/* Current throttle setting. */
};

#define THR_GET_REG(reg) 					\
	(bus_space_read_4(rman_get_bustag((reg)), 		\
			  rman_get_bushandle((reg)), 0))
#define THR_SET_REG(reg, val)					\
	(bus_space_write_4(rman_get_bustag((reg)), 		\
			   rman_get_bushandle((reg)), 0, (val)))

/*
 * Speeds are stored in counts, from 1 to CPU_MAX_SPEED, and
 * reported to the user in hundredths of a percent.
 */
#define CPU_MAX_SPEED		(1 << cpu_duty_width)
#define CPU_SPEED_PERCENT(x)	((10000 * (x)) / CPU_MAX_SPEED)
#define CPU_SPEED_PRINTABLE(x)	(CPU_SPEED_PERCENT(x) / 10),	\
				(CPU_SPEED_PERCENT(x) % 10)
#define CPU_P_CNT_THT_EN	(1<<4)
#define CPU_QUIRK_NO_THROTTLE	(1<<1)	/* Throttling is not usable. */

#define PCI_VENDOR_INTEL	0x8086
#define PCI_DEVICE_82371AB_3	0x7113	/* PIIX4 chipset for quirks. */
#define PCI_REVISION_A_STEP	0
#define PCI_REVISION_B_STEP	1

static uint32_t	cpu_duty_offset;	/* Offset in P_CNT of throttle val. */
static uint32_t	cpu_duty_width;		/* Bit width of throttle value. */
static int	thr_rid;		/* Driver-wide resource id. */
static int	thr_quirks;		/* Indicate any hardware bugs. */

static void	acpi_throttle_identify(driver_t *driver, device_t parent);
static int	acpi_throttle_probe(device_t dev);
static int	acpi_throttle_attach(device_t dev);
static int	acpi_throttle_evaluate(struct acpi_throttle_softc *sc);
static int	acpi_throttle_quirks(struct acpi_throttle_softc *sc);
static int	acpi_thr_settings(device_t dev, struct cf_setting *sets,
		    int *count);
static int	acpi_thr_set(device_t dev, const struct cf_setting *set);
static int	acpi_thr_get(device_t dev, struct cf_setting *set);
static int	acpi_thr_type(device_t dev, int *type);

static device_method_t acpi_throttle_methods[] = {
	/* Device interface */
	DEVMETHOD(device_identify,	acpi_throttle_identify),
	DEVMETHOD(device_probe,		acpi_throttle_probe),
	DEVMETHOD(device_attach,	acpi_throttle_attach),

	/* cpufreq interface */
	DEVMETHOD(cpufreq_drv_set,	acpi_thr_set),
	DEVMETHOD(cpufreq_drv_get,	acpi_thr_get),
	DEVMETHOD(cpufreq_drv_type,	acpi_thr_type),
	DEVMETHOD(cpufreq_drv_settings,	acpi_thr_settings),
	{0, 0}
};

static driver_t acpi_throttle_driver = {
	"acpi_throttle",
	acpi_throttle_methods,
	sizeof(struct acpi_throttle_softc),
};

static devclass_t acpi_throttle_devclass;
DRIVER_MODULE(acpi_throttle, cpu, acpi_throttle_driver, acpi_throttle_devclass,
    0, 0);

static void
acpi_throttle_identify(driver_t *driver, device_t parent)
{
	ACPI_BUFFER buf;
	ACPI_HANDLE handle;
	ACPI_OBJECT *obj;

	/* Make sure we're not being doubly invoked. */
	if (device_find_child(parent, "acpi_throttle", -1))
		return;

	/* Check for a valid duty width and parent CPU type. */
	handle = acpi_get_handle(parent);
	if (handle == NULL)
		return;
	if (AcpiGbl_FADT.DutyWidth == 0 ||
	    acpi_get_type(parent) != ACPI_TYPE_PROCESSOR)
		return;

	/*
	 * Add a child if there's a non-NULL P_BLK and correct length, or
	 * if the _PTC method is present.
	 */
	buf.Pointer = NULL;
	buf.Length = ACPI_ALLOCATE_BUFFER;
	if (ACPI_FAILURE(AcpiEvaluateObject(handle, NULL, NULL, &buf)))
		return;
	obj = (ACPI_OBJECT *)buf.Pointer;
	if ((obj->Processor.PblkAddress && obj->Processor.PblkLength >= 4) ||
	    ACPI_SUCCESS(AcpiEvaluateObject(handle, "_PTC", NULL, NULL))) {
		if (BUS_ADD_CHILD(parent, 0, "acpi_throttle", -1) == NULL)
			device_printf(parent, "add throttle child failed\n");
	}
	AcpiOsFree(obj);
}

static int
acpi_throttle_probe(device_t dev)
{

	if (resource_disabled("acpi_throttle", 0))
		return (ENXIO);

	/*
	 * On i386 platforms at least, ACPI throttling is accomplished by
	 * the chipset modulating the STPCLK# pin based on the duty cycle.
	 * Since p4tcc uses the same mechanism (but internal to the CPU),
	 * we disable acpi_throttle when p4tcc is also present.
	 */
	if (device_find_child(device_get_parent(dev), "p4tcc", -1) &&
	    !resource_disabled("p4tcc", 0))
		return (ENXIO);

	device_set_desc(dev, "ACPI CPU Throttling");
	return (0);
}

static int
acpi_throttle_attach(device_t dev)
{
	struct acpi_throttle_softc *sc;
	struct cf_setting set;
	ACPI_BUFFER buf;
	ACPI_OBJECT *obj;
	ACPI_STATUS status;
	int error;

	sc = device_get_softc(dev);
	sc->cpu_dev = dev;
	sc->cpu_handle = acpi_get_handle(dev);

	buf.Pointer = NULL;
	buf.Length = ACPI_ALLOCATE_BUFFER;
	status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
	if (ACPI_FAILURE(status)) {
		device_printf(dev, "attach failed to get Processor obj - %s\n",
		    AcpiFormatException(status));
		return (ENXIO);
	}
	obj = (ACPI_OBJECT *)buf.Pointer;
	sc->cpu_p_blk = obj->Processor.PblkAddress;
	sc->cpu_p_blk_len = obj->Processor.PblkLength;
	AcpiOsFree(obj);

	/* If this is the first device probed, check for quirks. */
	if (device_get_unit(dev) == 0)
		acpi_throttle_quirks(sc);

	/* Attempt to attach the actual throttling register. */
	error = acpi_throttle_evaluate(sc);
	if (error)
		return (error);

	/*
	 * Set our initial frequency to the highest since some systems
	 * seem to boot with this at the lowest setting.
	 */
	set.freq = 10000;
	acpi_thr_set(dev, &set);

	/* Everything went ok, register with cpufreq(4). */
	cpufreq_register(dev);
	return (0);
}

static int
acpi_throttle_evaluate(struct acpi_throttle_softc *sc)
{
	uint32_t duty_end;
	ACPI_BUFFER buf;
	ACPI_OBJECT obj;
	ACPI_GENERIC_ADDRESS gas;
	ACPI_STATUS status;

	/* Get throttling parameters from the FADT.  0 means not supported. */
	if (device_get_unit(sc->cpu_dev) == 0) {
		cpu_duty_offset = AcpiGbl_FADT.DutyOffset;
		cpu_duty_width = AcpiGbl_FADT.DutyWidth;
	}
	if (cpu_duty_width == 0 || (thr_quirks & CPU_QUIRK_NO_THROTTLE) != 0)
		return (ENXIO);

	/* Validate the duty offset/width. */
	duty_end = cpu_duty_offset + cpu_duty_width - 1;
	if (duty_end > 31) {
		device_printf(sc->cpu_dev,
		    "CLK_VAL field overflows P_CNT register\n");
		return (ENXIO);
	}
	if (cpu_duty_offset <= 4 && duty_end >= 4) {
		device_printf(sc->cpu_dev,
		    "CLK_VAL field overlaps THT_EN bit\n");
		return (ENXIO);
	}

	/*
	 * If not present, fall back to using the processor's P_BLK to find
	 * the P_CNT register.
	 *
	 * Note that some systems seem to duplicate the P_BLK pointer
	 * across multiple CPUs, so not getting the resource is not fatal.
	 */
	buf.Pointer = &obj;
	buf.Length = sizeof(obj);
	status = AcpiEvaluateObject(sc->cpu_handle, "_PTC", NULL, &buf);
	if (ACPI_SUCCESS(status)) {
		if (obj.Buffer.Length < sizeof(ACPI_GENERIC_ADDRESS) + 3) {
			device_printf(sc->cpu_dev, "_PTC buffer too small\n");
			return (ENXIO);
		}
		memcpy(&gas, obj.Buffer.Pointer + 3, sizeof(gas));
		acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
		    &gas, &sc->cpu_p_cnt, 0);
		if (sc->cpu_p_cnt != NULL && bootverbose) {
			device_printf(sc->cpu_dev, "P_CNT from _PTC %#jx\n",
			    gas.Address);
		}
	}

	/* If _PTC not present or other failure, try the P_BLK. */
	if (sc->cpu_p_cnt == NULL) {
		/* 
		 * The spec says P_BLK must be 6 bytes long.  However, some
		 * systems use it to indicate a fractional set of features
		 * present so we take anything >= 4.
		 */
		if (sc->cpu_p_blk_len < 4)
			return (ENXIO);
		gas.Address = sc->cpu_p_blk;
		gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
		gas.BitWidth = 32;
		acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
		    &gas, &sc->cpu_p_cnt, 0);
		if (sc->cpu_p_cnt != NULL) {
			if (bootverbose)
				device_printf(sc->cpu_dev,
				    "P_CNT from P_BLK %#x\n", sc->cpu_p_blk);
		} else {
			device_printf(sc->cpu_dev, "failed to attach P_CNT\n");
			return (ENXIO);
		}
	}
	thr_rid++;

	return (0);
}

static int
acpi_throttle_quirks(struct acpi_throttle_softc *sc)
{
	device_t acpi_dev;

	/* Look for various quirks of the PIIX4 part. */
	acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
	if (acpi_dev) {
		switch (pci_get_revid(acpi_dev)) {
		/*
		 * Disable throttling control on PIIX4 A and B-step.
		 * See specification changes #13 ("Manual Throttle Duty Cycle")
		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
		 * erratum #5 ("STPCLK# Deassertion Time") from the January
		 * 2002 PIIX4 specification update.  Note that few (if any)
		 * mobile systems ever used this part.
		 */
		case PCI_REVISION_A_STEP:
		case PCI_REVISION_B_STEP:
			thr_quirks |= CPU_QUIRK_NO_THROTTLE;
			break;
		default:
			break;
		}
	}

	return (0);
}

static int
acpi_thr_settings(device_t dev, struct cf_setting *sets, int *count)
{
	int i, speed;

	if (sets == NULL || count == NULL)
		return (EINVAL);
	if (*count < CPU_MAX_SPEED)
		return (E2BIG);

	/* Return a list of valid settings for this driver. */
	memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * CPU_MAX_SPEED);
	for (i = 0, speed = CPU_MAX_SPEED; speed != 0; i++, speed--) {
		sets[i].freq = CPU_SPEED_PERCENT(speed);
		sets[i].dev = dev;
	}
	*count = CPU_MAX_SPEED;

	return (0);
}

static int
acpi_thr_set(device_t dev, const struct cf_setting *set)
{
	struct acpi_throttle_softc *sc;
	uint32_t clk_val, p_cnt, speed;

	if (set == NULL)
		return (EINVAL);
	sc = device_get_softc(dev);

	/*
	 * Validate requested state converts to a duty cycle that is an
	 * integer from [1 .. CPU_MAX_SPEED].
	 */
	speed = set->freq * CPU_MAX_SPEED / 10000;
	if (speed * 10000 != set->freq * CPU_MAX_SPEED ||
	    speed < 1 || speed > CPU_MAX_SPEED)
		return (EINVAL);

	/* If we're at this setting, don't bother applying it again. */
	if (speed == sc->cpu_thr_state)
		return (0);

	/* Get the current P_CNT value and disable throttling */
	p_cnt = THR_GET_REG(sc->cpu_p_cnt);
	p_cnt &= ~CPU_P_CNT_THT_EN;
	THR_SET_REG(sc->cpu_p_cnt, p_cnt);

	/* If we're at maximum speed, that's all */
	if (speed < CPU_MAX_SPEED) {
		/* Mask the old CLK_VAL off and OR in the new value */
		clk_val = (CPU_MAX_SPEED - 1) << cpu_duty_offset;
		p_cnt &= ~clk_val;
		p_cnt |= (speed << cpu_duty_offset);

		/* Write the new P_CNT value and then enable throttling */
		THR_SET_REG(sc->cpu_p_cnt, p_cnt);
		p_cnt |= CPU_P_CNT_THT_EN;
		THR_SET_REG(sc->cpu_p_cnt, p_cnt);
	}
	sc->cpu_thr_state = speed;

	return (0);
}

static int
acpi_thr_get(device_t dev, struct cf_setting *set)
{
	struct acpi_throttle_softc *sc;
	uint32_t p_cnt, clk_val;

	if (set == NULL)
		return (EINVAL);
	sc = device_get_softc(dev);

	/* Get the current throttling setting from P_CNT. */
	p_cnt = THR_GET_REG(sc->cpu_p_cnt);
	clk_val = (p_cnt >> cpu_duty_offset) & (CPU_MAX_SPEED - 1);
	sc->cpu_thr_state = clk_val;

	memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
	set->freq = CPU_SPEED_PERCENT(clk_val);
	set->dev = dev;

	return (0);
}

static int
acpi_thr_type(device_t dev, int *type)
{

	if (type == NULL)
		return (EINVAL);

	*type = CPUFREQ_TYPE_RELATIVE;
	return (0);
}
OpenPOWER on IntegriCloud