xref: /freebsd/sys/dev/acpica/acpi_throttle.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*-
2  * Copyright (c) 2003-2005 Nate Lawson (SDG)
3  * Copyright (c) 2001 Michael Smith
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *	notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *	notice, this list of conditions and the following disclaimer in the
13  *	documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30 
31 #include "opt_acpi.h"
32 #include <sys/param.h>
33 #include <sys/bus.h>
34 #include <sys/cpu.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/module.h>
38 #include <sys/rman.h>
39 
40 #include <machine/bus.h>
41 
42 #include <contrib/dev/acpica/acpi.h>
43 #include <dev/acpica/acpivar.h>
44 #include <dev/pci/pcivar.h>
45 
46 #include "cpufreq_if.h"
47 
48 /*
49  * Throttling provides relative frequency control.  It involves modulating
50  * the clock so that the CPU is active for only a fraction of the normal
51  * clock cycle.  It does not change voltage and so is less efficient than
52  * other mechanisms.  Since it is relative, it can be used in addition to
53  * absolute cpufreq drivers.  We support the ACPI 2.0 specification.
54  */
55 
56 struct acpi_throttle_softc {
57 	device_t	 cpu_dev;
58 	ACPI_HANDLE	 cpu_handle;
59 	uint32_t	 cpu_p_blk;	/* ACPI P_BLK location */
60 	uint32_t	 cpu_p_blk_len;	/* P_BLK length (must be 6). */
61 	struct resource	*cpu_p_cnt;	/* Throttling control register */
62 	int		 cpu_p_type;	/* Resource type for cpu_p_cnt. */
63 	uint32_t	 cpu_thr_state;	/* Current throttle setting. */
64 };
65 
66 #define THR_GET_REG(reg) 					\
67 	(bus_space_read_4(rman_get_bustag((reg)), 		\
68 			  rman_get_bushandle((reg)), 0))
69 #define THR_SET_REG(reg, val)					\
70 	(bus_space_write_4(rman_get_bustag((reg)), 		\
71 			   rman_get_bushandle((reg)), 0, (val)))
72 
73 /*
74  * Speeds are stored in counts, from 1 to CPU_MAX_SPEED, and
75  * reported to the user in hundredths of a percent.
76  */
77 #define CPU_MAX_SPEED		(1 << cpu_duty_width)
78 #define CPU_SPEED_PERCENT(x)	((10000 * (x)) / CPU_MAX_SPEED)
79 #define CPU_SPEED_PRINTABLE(x)	(CPU_SPEED_PERCENT(x) / 10),	\
80 				(CPU_SPEED_PERCENT(x) % 10)
81 #define CPU_P_CNT_THT_EN	(1<<4)
82 #define CPU_QUIRK_NO_THROTTLE	(1<<1)	/* Throttling is not usable. */
83 
84 #define PCI_VENDOR_INTEL	0x8086
85 #define PCI_DEVICE_82371AB_3	0x7113	/* PIIX4 chipset for quirks. */
86 #define PCI_REVISION_A_STEP	0
87 #define PCI_REVISION_B_STEP	1
88 
89 static uint32_t	cpu_duty_offset;	/* Offset in P_CNT of throttle val. */
90 static uint32_t	cpu_duty_width;		/* Bit width of throttle value. */
91 static int	thr_rid;		/* Driver-wide resource id. */
92 static int	thr_quirks;		/* Indicate any hardware bugs. */
93 
94 static void	acpi_throttle_identify(driver_t *driver, device_t parent);
95 static int	acpi_throttle_probe(device_t dev);
96 static int	acpi_throttle_attach(device_t dev);
97 static int	acpi_throttle_evaluate(struct acpi_throttle_softc *sc);
98 static int	acpi_throttle_quirks(struct acpi_throttle_softc *sc);
99 static int	acpi_thr_settings(device_t dev, struct cf_setting *sets,
100 		    int *count);
101 static int	acpi_thr_set(device_t dev, const struct cf_setting *set);
102 static int	acpi_thr_get(device_t dev, struct cf_setting *set);
103 static int	acpi_thr_type(device_t dev, int *type);
104 
105 static device_method_t acpi_throttle_methods[] = {
106 	/* Device interface */
107 	DEVMETHOD(device_identify,	acpi_throttle_identify),
108 	DEVMETHOD(device_probe,		acpi_throttle_probe),
109 	DEVMETHOD(device_attach,	acpi_throttle_attach),
110 
111 	/* cpufreq interface */
112 	DEVMETHOD(cpufreq_drv_set,	acpi_thr_set),
113 	DEVMETHOD(cpufreq_drv_get,	acpi_thr_get),
114 	DEVMETHOD(cpufreq_drv_type,	acpi_thr_type),
115 	DEVMETHOD(cpufreq_drv_settings,	acpi_thr_settings),
116 	{0, 0}
117 };
118 
119 static driver_t acpi_throttle_driver = {
120 	"acpi_throttle",
121 	acpi_throttle_methods,
122 	sizeof(struct acpi_throttle_softc),
123 };
124 
125 static devclass_t acpi_throttle_devclass;
126 DRIVER_MODULE(acpi_throttle, cpu, acpi_throttle_driver, acpi_throttle_devclass,
127     0, 0);
128 
129 static void
130 acpi_throttle_identify(driver_t *driver, device_t parent)
131 {
132 	ACPI_BUFFER buf;
133 	ACPI_HANDLE handle;
134 	ACPI_OBJECT *obj;
135 
136 	/* Make sure we're not being doubly invoked. */
137 	if (device_find_child(parent, "acpi_throttle", -1))
138 		return;
139 
140 	/* Check for a valid duty width and parent CPU type. */
141 	handle = acpi_get_handle(parent);
142 	if (handle == NULL)
143 		return;
144 	if (AcpiGbl_FADT.DutyWidth == 0 ||
145 	    acpi_get_type(parent) != ACPI_TYPE_PROCESSOR)
146 		return;
147 
148 	/*
149 	 * Add a child if there's a non-NULL P_BLK and correct length, or
150 	 * if the _PTC method is present.
151 	 */
152 	buf.Pointer = NULL;
153 	buf.Length = ACPI_ALLOCATE_BUFFER;
154 	if (ACPI_FAILURE(AcpiEvaluateObject(handle, NULL, NULL, &buf)))
155 		return;
156 	obj = (ACPI_OBJECT *)buf.Pointer;
157 	if ((obj->Processor.PblkAddress && obj->Processor.PblkLength >= 4) ||
158 	    ACPI_SUCCESS(AcpiEvaluateObject(handle, "_PTC", NULL, NULL))) {
159 		if (BUS_ADD_CHILD(parent, 0, "acpi_throttle", -1) == NULL)
160 			device_printf(parent, "add throttle child failed\n");
161 	}
162 	AcpiOsFree(obj);
163 }
164 
165 static int
166 acpi_throttle_probe(device_t dev)
167 {
168 
169 	if (resource_disabled("acpi_throttle", 0))
170 		return (ENXIO);
171 
172 	/*
173 	 * On i386 platforms at least, ACPI throttling is accomplished by
174 	 * the chipset modulating the STPCLK# pin based on the duty cycle.
175 	 * Since p4tcc uses the same mechanism (but internal to the CPU),
176 	 * we disable acpi_throttle when p4tcc is also present.
177 	 */
178 	if (device_find_child(device_get_parent(dev), "p4tcc", -1) &&
179 	    !resource_disabled("p4tcc", 0))
180 		return (ENXIO);
181 
182 	device_set_desc(dev, "ACPI CPU Throttling");
183 	return (0);
184 }
185 
186 static int
187 acpi_throttle_attach(device_t dev)
188 {
189 	struct acpi_throttle_softc *sc;
190 	struct cf_setting set;
191 	ACPI_BUFFER buf;
192 	ACPI_OBJECT *obj;
193 	ACPI_STATUS status;
194 	int error;
195 
196 	sc = device_get_softc(dev);
197 	sc->cpu_dev = dev;
198 	sc->cpu_handle = acpi_get_handle(dev);
199 
200 	buf.Pointer = NULL;
201 	buf.Length = ACPI_ALLOCATE_BUFFER;
202 	status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
203 	if (ACPI_FAILURE(status)) {
204 		device_printf(dev, "attach failed to get Processor obj - %s\n",
205 		    AcpiFormatException(status));
206 		return (ENXIO);
207 	}
208 	obj = (ACPI_OBJECT *)buf.Pointer;
209 	sc->cpu_p_blk = obj->Processor.PblkAddress;
210 	sc->cpu_p_blk_len = obj->Processor.PblkLength;
211 	AcpiOsFree(obj);
212 
213 	/* If this is the first device probed, check for quirks. */
214 	if (device_get_unit(dev) == 0)
215 		acpi_throttle_quirks(sc);
216 
217 	/* Attempt to attach the actual throttling register. */
218 	error = acpi_throttle_evaluate(sc);
219 	if (error)
220 		return (error);
221 
222 	/*
223 	 * Set our initial frequency to the highest since some systems
224 	 * seem to boot with this at the lowest setting.
225 	 */
226 	set.freq = 10000;
227 	acpi_thr_set(dev, &set);
228 
229 	/* Everything went ok, register with cpufreq(4). */
230 	cpufreq_register(dev);
231 	return (0);
232 }
233 
234 static int
235 acpi_throttle_evaluate(struct acpi_throttle_softc *sc)
236 {
237 	uint32_t duty_end;
238 	ACPI_BUFFER buf;
239 	ACPI_OBJECT obj;
240 	ACPI_GENERIC_ADDRESS gas;
241 	ACPI_STATUS status;
242 
243 	/* Get throttling parameters from the FADT.  0 means not supported. */
244 	if (device_get_unit(sc->cpu_dev) == 0) {
245 		cpu_duty_offset = AcpiGbl_FADT.DutyOffset;
246 		cpu_duty_width = AcpiGbl_FADT.DutyWidth;
247 	}
248 	if (cpu_duty_width == 0 || (thr_quirks & CPU_QUIRK_NO_THROTTLE) != 0)
249 		return (ENXIO);
250 
251 	/* Validate the duty offset/width. */
252 	duty_end = cpu_duty_offset + cpu_duty_width - 1;
253 	if (duty_end > 31) {
254 		device_printf(sc->cpu_dev,
255 		    "CLK_VAL field overflows P_CNT register\n");
256 		return (ENXIO);
257 	}
258 	if (cpu_duty_offset <= 4 && duty_end >= 4) {
259 		device_printf(sc->cpu_dev,
260 		    "CLK_VAL field overlaps THT_EN bit\n");
261 		return (ENXIO);
262 	}
263 
264 	/*
265 	 * If not present, fall back to using the processor's P_BLK to find
266 	 * the P_CNT register.
267 	 *
268 	 * Note that some systems seem to duplicate the P_BLK pointer
269 	 * across multiple CPUs, so not getting the resource is not fatal.
270 	 */
271 	buf.Pointer = &obj;
272 	buf.Length = sizeof(obj);
273 	status = AcpiEvaluateObject(sc->cpu_handle, "_PTC", NULL, &buf);
274 	if (ACPI_SUCCESS(status)) {
275 		if (obj.Buffer.Length < sizeof(ACPI_GENERIC_ADDRESS) + 3) {
276 			device_printf(sc->cpu_dev, "_PTC buffer too small\n");
277 			return (ENXIO);
278 		}
279 		memcpy(&gas, obj.Buffer.Pointer + 3, sizeof(gas));
280 		acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
281 		    &gas, &sc->cpu_p_cnt, 0);
282 		if (sc->cpu_p_cnt != NULL && bootverbose) {
283 			device_printf(sc->cpu_dev, "P_CNT from _PTC %#jx\n",
284 			    gas.Address);
285 		}
286 	}
287 
288 	/* If _PTC not present or other failure, try the P_BLK. */
289 	if (sc->cpu_p_cnt == NULL) {
290 		/*
291 		 * The spec says P_BLK must be 6 bytes long.  However, some
292 		 * systems use it to indicate a fractional set of features
293 		 * present so we take anything >= 4.
294 		 */
295 		if (sc->cpu_p_blk_len < 4)
296 			return (ENXIO);
297 		gas.Address = sc->cpu_p_blk;
298 		gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
299 		gas.BitWidth = 32;
300 		acpi_bus_alloc_gas(sc->cpu_dev, &sc->cpu_p_type, &thr_rid,
301 		    &gas, &sc->cpu_p_cnt, 0);
302 		if (sc->cpu_p_cnt != NULL) {
303 			if (bootverbose)
304 				device_printf(sc->cpu_dev,
305 				    "P_CNT from P_BLK %#x\n", sc->cpu_p_blk);
306 		} else {
307 			device_printf(sc->cpu_dev, "failed to attach P_CNT\n");
308 			return (ENXIO);
309 		}
310 	}
311 	thr_rid++;
312 
313 	return (0);
314 }
315 
316 static int
317 acpi_throttle_quirks(struct acpi_throttle_softc *sc)
318 {
319 	device_t acpi_dev;
320 
321 	/* Look for various quirks of the PIIX4 part. */
322 	acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
323 	if (acpi_dev) {
324 		switch (pci_get_revid(acpi_dev)) {
325 		/*
326 		 * Disable throttling control on PIIX4 A and B-step.
327 		 * See specification changes #13 ("Manual Throttle Duty Cycle")
328 		 * and #14 ("Enabling and Disabling Manual Throttle"), plus
329 		 * erratum #5 ("STPCLK# Deassertion Time") from the January
330 		 * 2002 PIIX4 specification update.  Note that few (if any)
331 		 * mobile systems ever used this part.
332 		 */
333 		case PCI_REVISION_A_STEP:
334 		case PCI_REVISION_B_STEP:
335 			thr_quirks |= CPU_QUIRK_NO_THROTTLE;
336 			break;
337 		default:
338 			break;
339 		}
340 	}
341 
342 	return (0);
343 }
344 
345 static int
346 acpi_thr_settings(device_t dev, struct cf_setting *sets, int *count)
347 {
348 	int i, speed;
349 
350 	if (sets == NULL || count == NULL)
351 		return (EINVAL);
352 	if (*count < CPU_MAX_SPEED)
353 		return (E2BIG);
354 
355 	/* Return a list of valid settings for this driver. */
356 	memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * CPU_MAX_SPEED);
357 	for (i = 0, speed = CPU_MAX_SPEED; speed != 0; i++, speed--) {
358 		sets[i].freq = CPU_SPEED_PERCENT(speed);
359 		sets[i].dev = dev;
360 	}
361 	*count = CPU_MAX_SPEED;
362 
363 	return (0);
364 }
365 
366 static int
367 acpi_thr_set(device_t dev, const struct cf_setting *set)
368 {
369 	struct acpi_throttle_softc *sc;
370 	uint32_t clk_val, p_cnt, speed;
371 
372 	if (set == NULL)
373 		return (EINVAL);
374 	sc = device_get_softc(dev);
375 
376 	/*
377 	 * Validate requested state converts to a duty cycle that is an
378 	 * integer from [1 .. CPU_MAX_SPEED].
379 	 */
380 	speed = set->freq * CPU_MAX_SPEED / 10000;
381 	if (speed * 10000 != set->freq * CPU_MAX_SPEED ||
382 	    speed < 1 || speed > CPU_MAX_SPEED)
383 		return (EINVAL);
384 
385 	/* If we're at this setting, don't bother applying it again. */
386 	if (speed == sc->cpu_thr_state)
387 		return (0);
388 
389 	/* Get the current P_CNT value and disable throttling */
390 	p_cnt = THR_GET_REG(sc->cpu_p_cnt);
391 	p_cnt &= ~CPU_P_CNT_THT_EN;
392 	THR_SET_REG(sc->cpu_p_cnt, p_cnt);
393 
394 	/* If we're at maximum speed, that's all */
395 	if (speed < CPU_MAX_SPEED) {
396 		/* Mask the old CLK_VAL off and OR in the new value */
397 		clk_val = (CPU_MAX_SPEED - 1) << cpu_duty_offset;
398 		p_cnt &= ~clk_val;
399 		p_cnt |= (speed << cpu_duty_offset);
400 
401 		/* Write the new P_CNT value and then enable throttling */
402 		THR_SET_REG(sc->cpu_p_cnt, p_cnt);
403 		p_cnt |= CPU_P_CNT_THT_EN;
404 		THR_SET_REG(sc->cpu_p_cnt, p_cnt);
405 	}
406 	sc->cpu_thr_state = speed;
407 
408 	return (0);
409 }
410 
411 static int
412 acpi_thr_get(device_t dev, struct cf_setting *set)
413 {
414 	struct acpi_throttle_softc *sc;
415 	uint32_t p_cnt, clk_val;
416 
417 	if (set == NULL)
418 		return (EINVAL);
419 	sc = device_get_softc(dev);
420 
421 	/* Get the current throttling setting from P_CNT. */
422 	p_cnt = THR_GET_REG(sc->cpu_p_cnt);
423 	clk_val = (p_cnt >> cpu_duty_offset) & (CPU_MAX_SPEED - 1);
424 	sc->cpu_thr_state = clk_val;
425 
426 	memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
427 	set->freq = CPU_SPEED_PERCENT(clk_val);
428 	set->dev = dev;
429 
430 	return (0);
431 }
432 
433 static int
434 acpi_thr_type(device_t dev, int *type)
435 {
436 
437 	if (type == NULL)
438 		return (EINVAL);
439 
440 	*type = CPUFREQ_TYPE_RELATIVE;
441 	return (0);
442 }
443