xref: /freebsd/sys/dev/acpica/acpi_cpu.c (revision 830940567b49bb0c08dfaed40418999e76616909)
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/pcpu.h>
39 #include <sys/power.h>
40 #include <sys/proc.h>
41 #include <sys/sbuf.h>
42 #include <sys/smp.h>
43 
44 #include <dev/pci/pcivar.h>
45 #include <machine/atomic.h>
46 #include <machine/bus.h>
47 #include <sys/rman.h>
48 
49 #include <contrib/dev/acpica/include/acpi.h>
50 #include <contrib/dev/acpica/include/accommon.h>
51 
52 #include <dev/acpica/acpivar.h>
53 
54 /*
55  * Support for ACPI Processor devices, including C[1-3] sleep states.
56  */
57 
58 /* Hooks for the ACPI CA debugging infrastructure */
59 #define _COMPONENT	ACPI_PROCESSOR
60 ACPI_MODULE_NAME("PROCESSOR")
61 
62 struct acpi_cx {
63     struct resource	*p_lvlx;	/* Register to read to enter state. */
64     uint32_t		 type;		/* C1-3 (C4 and up treated as C3). */
65     uint32_t		 trans_lat;	/* Transition latency (usec). */
66     uint32_t		 power;		/* Power consumed (mW). */
67     int			 res_type;	/* Resource type for p_lvlx. */
68 };
69 #define MAX_CX_STATES	 8
70 
71 struct acpi_cpu_softc {
72     device_t		 cpu_dev;
73     ACPI_HANDLE		 cpu_handle;
74     struct pcpu		*cpu_pcpu;
75     uint32_t		 cpu_acpi_id;	/* ACPI processor id */
76     uint32_t		 cpu_p_blk;	/* ACPI P_BLK location */
77     uint32_t		 cpu_p_blk_len;	/* P_BLK length (must be 6). */
78     struct acpi_cx	 cpu_cx_states[MAX_CX_STATES];
79     int			 cpu_cx_count;	/* Number of valid Cx states. */
80     int			 cpu_prev_sleep;/* Last idle sleep duration. */
81     int			 cpu_features;	/* Child driver supported features. */
82     /* Runtime state. */
83     int			 cpu_non_c3;	/* Index of lowest non-C3 state. */
84     u_int		 cpu_cx_stats[MAX_CX_STATES];/* Cx usage history. */
85     /* Values for sysctl. */
86     struct sysctl_ctx_list cpu_sysctl_ctx;
87     struct sysctl_oid	*cpu_sysctl_tree;
88     int			 cpu_cx_lowest;
89     char 		 cpu_cx_supported[64];
90     int			 cpu_rid;
91 };
92 
93 struct acpi_cpu_device {
94     struct resource_list	ad_rl;
95 };
96 
97 #define CPU_GET_REG(reg, width) 					\
98     (bus_space_read_ ## width(rman_get_bustag((reg)), 			\
99 		      rman_get_bushandle((reg)), 0))
100 #define CPU_SET_REG(reg, width, val)					\
101     (bus_space_write_ ## width(rman_get_bustag((reg)), 			\
102 		       rman_get_bushandle((reg)), 0, (val)))
103 
104 #define PM_USEC(x)	 ((x) >> 2)	/* ~4 clocks per usec (3.57955 Mhz) */
105 
106 #define ACPI_NOTIFY_CX_STATES	0x81	/* _CST changed. */
107 
108 #define CPU_QUIRK_NO_C3		(1<<0)	/* C3-type states are not usable. */
109 #define CPU_QUIRK_NO_BM_CTRL	(1<<2)	/* No bus mastering control. */
110 
111 #define PCI_VENDOR_INTEL	0x8086
112 #define PCI_DEVICE_82371AB_3	0x7113	/* PIIX4 chipset for quirks. */
113 #define PCI_REVISION_A_STEP	0
114 #define PCI_REVISION_B_STEP	1
115 #define PCI_REVISION_4E		2
116 #define PCI_REVISION_4M		3
117 #define PIIX4_DEVACTB_REG	0x58
118 #define PIIX4_BRLD_EN_IRQ0	(1<<0)
119 #define PIIX4_BRLD_EN_IRQ	(1<<1)
120 #define PIIX4_BRLD_EN_IRQ8	(1<<5)
121 #define PIIX4_STOP_BREAK_MASK	(PIIX4_BRLD_EN_IRQ0 | PIIX4_BRLD_EN_IRQ | PIIX4_BRLD_EN_IRQ8)
122 #define PIIX4_PCNTRL_BST_EN	(1<<10)
123 
124 /* Platform hardware resource information. */
125 static uint32_t		 cpu_smi_cmd;	/* Value to write to SMI_CMD. */
126 static uint8_t		 cpu_cst_cnt;	/* Indicate we are _CST aware. */
127 static int		 cpu_quirks;	/* Indicate any hardware bugs. */
128 
129 /* Runtime state. */
130 static int		 cpu_disable_idle; /* Disable entry to idle function */
131 static int		 cpu_cx_count;	/* Number of valid Cx states */
132 
133 /* Values for sysctl. */
134 static struct sysctl_ctx_list cpu_sysctl_ctx;
135 static struct sysctl_oid *cpu_sysctl_tree;
136 static int		 cpu_cx_generic;
137 static int		 cpu_cx_lowest;
138 
139 static device_t		*cpu_devices;
140 static int		 cpu_ndevices;
141 static struct acpi_cpu_softc **cpu_softc;
142 ACPI_SERIAL_DECL(cpu, "ACPI CPU");
143 
144 static int	acpi_cpu_probe(device_t dev);
145 static int	acpi_cpu_attach(device_t dev);
146 static int	acpi_cpu_suspend(device_t dev);
147 static int	acpi_cpu_resume(device_t dev);
148 static int	acpi_pcpu_get_id(uint32_t idx, uint32_t *acpi_id,
149 		    uint32_t *cpu_id);
150 static struct resource_list *acpi_cpu_get_rlist(device_t dev, device_t child);
151 static device_t	acpi_cpu_add_child(device_t dev, int order, const char *name,
152 		    int unit);
153 static int	acpi_cpu_read_ivar(device_t dev, device_t child, int index,
154 		    uintptr_t *result);
155 static int	acpi_cpu_shutdown(device_t dev);
156 static void	acpi_cpu_cx_probe(struct acpi_cpu_softc *sc);
157 static void	acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc);
158 static int	acpi_cpu_cx_cst(struct acpi_cpu_softc *sc);
159 static void	acpi_cpu_startup(void *arg);
160 static void	acpi_cpu_startup_cx(struct acpi_cpu_softc *sc);
161 static void	acpi_cpu_cx_list(struct acpi_cpu_softc *sc);
162 static void	acpi_cpu_idle(void);
163 static void	acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context);
164 static int	acpi_cpu_quirks(void);
165 static int	acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS);
166 static int	acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val);
167 static int	acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
168 static int	acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
169 
170 static device_method_t acpi_cpu_methods[] = {
171     /* Device interface */
172     DEVMETHOD(device_probe,	acpi_cpu_probe),
173     DEVMETHOD(device_attach,	acpi_cpu_attach),
174     DEVMETHOD(device_detach,	bus_generic_detach),
175     DEVMETHOD(device_shutdown,	acpi_cpu_shutdown),
176     DEVMETHOD(device_suspend,	acpi_cpu_suspend),
177     DEVMETHOD(device_resume,	acpi_cpu_resume),
178 
179     /* Bus interface */
180     DEVMETHOD(bus_add_child,	acpi_cpu_add_child),
181     DEVMETHOD(bus_read_ivar,	acpi_cpu_read_ivar),
182     DEVMETHOD(bus_get_resource_list, acpi_cpu_get_rlist),
183     DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
184     DEVMETHOD(bus_set_resource,	bus_generic_rl_set_resource),
185     DEVMETHOD(bus_alloc_resource, bus_generic_rl_alloc_resource),
186     DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
187     DEVMETHOD(bus_driver_added,	bus_generic_driver_added),
188     DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
189     DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
190     DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
191     DEVMETHOD(bus_teardown_intr, bus_generic_teardown_intr),
192 
193     {0, 0}
194 };
195 
196 static driver_t acpi_cpu_driver = {
197     "cpu",
198     acpi_cpu_methods,
199     sizeof(struct acpi_cpu_softc),
200 };
201 
202 static devclass_t acpi_cpu_devclass;
203 DRIVER_MODULE(cpu, acpi, acpi_cpu_driver, acpi_cpu_devclass, 0, 0);
204 MODULE_DEPEND(cpu, acpi, 1, 1, 1);
205 
206 static int
207 acpi_cpu_probe(device_t dev)
208 {
209     int			   acpi_id, cpu_id;
210     ACPI_BUFFER		   buf;
211     ACPI_HANDLE		   handle;
212     ACPI_OBJECT		   *obj;
213     ACPI_STATUS		   status;
214 
215     if (acpi_disabled("cpu") || acpi_get_type(dev) != ACPI_TYPE_PROCESSOR)
216 	return (ENXIO);
217 
218     handle = acpi_get_handle(dev);
219     if (cpu_softc == NULL)
220 	cpu_softc = malloc(sizeof(struct acpi_cpu_softc *) *
221 	    (mp_maxid + 1), M_TEMP /* XXX */, M_WAITOK | M_ZERO);
222 
223     /* Get our Processor object. */
224     buf.Pointer = NULL;
225     buf.Length = ACPI_ALLOCATE_BUFFER;
226     status = AcpiEvaluateObject(handle, NULL, NULL, &buf);
227     if (ACPI_FAILURE(status)) {
228 	device_printf(dev, "probe failed to get Processor obj - %s\n",
229 		      AcpiFormatException(status));
230 	return (ENXIO);
231     }
232     obj = (ACPI_OBJECT *)buf.Pointer;
233     if (obj->Type != ACPI_TYPE_PROCESSOR) {
234 	device_printf(dev, "Processor object has bad type %d\n", obj->Type);
235 	AcpiOsFree(obj);
236 	return (ENXIO);
237     }
238 
239     /*
240      * Find the processor associated with our unit.  We could use the
241      * ProcId as a key, however, some boxes do not have the same values
242      * in their Processor object as the ProcId values in the MADT.
243      */
244     acpi_id = obj->Processor.ProcId;
245     AcpiOsFree(obj);
246     if (acpi_pcpu_get_id(device_get_unit(dev), &acpi_id, &cpu_id) != 0)
247 	return (ENXIO);
248 
249     /*
250      * Check if we already probed this processor.  We scan the bus twice
251      * so it's possible we've already seen this one.
252      */
253     if (cpu_softc[cpu_id] != NULL)
254 	return (ENXIO);
255 
256     /* Mark this processor as in-use and save our derived id for attach. */
257     cpu_softc[cpu_id] = (void *)1;
258     acpi_set_magic(dev, cpu_id);
259     device_set_desc(dev, "ACPI CPU");
260 
261     return (0);
262 }
263 
264 static int
265 acpi_cpu_attach(device_t dev)
266 {
267     ACPI_BUFFER		   buf;
268     ACPI_OBJECT		   arg[4], *obj;
269     ACPI_OBJECT_LIST	   arglist;
270     struct pcpu		   *pcpu_data;
271     struct acpi_cpu_softc *sc;
272     struct acpi_softc	  *acpi_sc;
273     ACPI_STATUS		   status;
274     u_int		   features;
275     int			   cpu_id, drv_count, i;
276     driver_t 		  **drivers;
277     uint32_t		   cap_set[3];
278 
279     /* UUID needed by _OSC evaluation */
280     static uint8_t cpu_oscuuid[16] = { 0x16, 0xA6, 0x77, 0x40, 0x0C, 0x29,
281 				       0xBE, 0x47, 0x9E, 0xBD, 0xD8, 0x70,
282 				       0x58, 0x71, 0x39, 0x53 };
283 
284     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
285 
286     sc = device_get_softc(dev);
287     sc->cpu_dev = dev;
288     sc->cpu_handle = acpi_get_handle(dev);
289     cpu_id = acpi_get_magic(dev);
290     cpu_softc[cpu_id] = sc;
291     pcpu_data = pcpu_find(cpu_id);
292     pcpu_data->pc_device = dev;
293     sc->cpu_pcpu = pcpu_data;
294     cpu_smi_cmd = AcpiGbl_FADT.SmiCommand;
295     cpu_cst_cnt = AcpiGbl_FADT.CstControl;
296 
297     buf.Pointer = NULL;
298     buf.Length = ACPI_ALLOCATE_BUFFER;
299     status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
300     if (ACPI_FAILURE(status)) {
301 	device_printf(dev, "attach failed to get Processor obj - %s\n",
302 		      AcpiFormatException(status));
303 	return (ENXIO);
304     }
305     obj = (ACPI_OBJECT *)buf.Pointer;
306     sc->cpu_p_blk = obj->Processor.PblkAddress;
307     sc->cpu_p_blk_len = obj->Processor.PblkLength;
308     sc->cpu_acpi_id = obj->Processor.ProcId;
309     AcpiOsFree(obj);
310     ACPI_DEBUG_PRINT((ACPI_DB_INFO, "acpi_cpu%d: P_BLK at %#x/%d\n",
311 		     device_get_unit(dev), sc->cpu_p_blk, sc->cpu_p_blk_len));
312 
313     /*
314      * If this is the first cpu we attach, create and initialize the generic
315      * resources that will be used by all acpi cpu devices.
316      */
317     if (device_get_unit(dev) == 0) {
318 	/* Assume we won't be using generic Cx mode by default */
319 	cpu_cx_generic = FALSE;
320 
321 	/* Install hw.acpi.cpu sysctl tree */
322 	acpi_sc = acpi_device_get_parent_softc(dev);
323 	sysctl_ctx_init(&cpu_sysctl_ctx);
324 	cpu_sysctl_tree = SYSCTL_ADD_NODE(&cpu_sysctl_ctx,
325 	    SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree), OID_AUTO, "cpu",
326 	    CTLFLAG_RD, 0, "node for CPU children");
327 
328 	/* Queue post cpu-probing task handler */
329 	AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_cpu_startup, NULL);
330     }
331 
332     /*
333      * Before calling any CPU methods, collect child driver feature hints
334      * and notify ACPI of them.  We support unified SMP power control
335      * so advertise this ourselves.  Note this is not the same as independent
336      * SMP control where each CPU can have different settings.
337      */
338     sc->cpu_features = ACPI_CAP_SMP_SAME | ACPI_CAP_SMP_SAME_C3;
339     if (devclass_get_drivers(acpi_cpu_devclass, &drivers, &drv_count) == 0) {
340 	for (i = 0; i < drv_count; i++) {
341 	    if (ACPI_GET_FEATURES(drivers[i], &features) == 0)
342 		sc->cpu_features |= features;
343 	}
344 	free(drivers, M_TEMP);
345     }
346 
347     /*
348      * CPU capabilities are specified as a buffer of 32-bit integers:
349      * revision, count, and one or more capabilities.  The revision of
350      * "1" is not specified anywhere but seems to match Linux.
351      */
352     if (sc->cpu_features) {
353 	arglist.Pointer = arg;
354 	arglist.Count = 1;
355 	arg[0].Type = ACPI_TYPE_BUFFER;
356 	arg[0].Buffer.Length = sizeof(cap_set);
357 	arg[0].Buffer.Pointer = (uint8_t *)cap_set;
358 	cap_set[0] = 1; /* revision */
359 	cap_set[1] = 1; /* number of capabilities integers */
360 	cap_set[2] = sc->cpu_features;
361 	AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
362 
363 	/*
364 	 * On some systems we need to evaluate _OSC so that the ASL
365 	 * loads the _PSS and/or _PDC methods at runtime.
366 	 *
367 	 * TODO: evaluate failure of _OSC.
368 	 */
369 	arglist.Pointer = arg;
370 	arglist.Count = 4;
371 	arg[0].Type = ACPI_TYPE_BUFFER;
372 	arg[0].Buffer.Length = sizeof(cpu_oscuuid);
373 	arg[0].Buffer.Pointer = cpu_oscuuid;	/* UUID */
374 	arg[1].Type = ACPI_TYPE_INTEGER;
375 	arg[1].Integer.Value = 1;		/* revision */
376 	arg[2].Type = ACPI_TYPE_INTEGER;
377 	arg[2].Integer.Value = 1;		/* count */
378 	arg[3].Type = ACPI_TYPE_BUFFER;
379 	arg[3].Buffer.Length = sizeof(cap_set);	/* Capabilities buffer */
380 	arg[3].Buffer.Pointer = (uint8_t *)cap_set;
381 	cap_set[0] = 0;
382 	AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
383     }
384 
385     /* Probe for Cx state support. */
386     acpi_cpu_cx_probe(sc);
387 
388     /* Finally,  call identify and probe/attach for child devices. */
389     bus_generic_probe(dev);
390     bus_generic_attach(dev);
391 
392     return (0);
393 }
394 
395 /*
396  * Disable any entry to the idle function during suspend and re-enable it
397  * during resume.
398  */
399 static int
400 acpi_cpu_suspend(device_t dev)
401 {
402     int error;
403 
404     error = bus_generic_suspend(dev);
405     if (error)
406 	return (error);
407     cpu_disable_idle = TRUE;
408     return (0);
409 }
410 
411 static int
412 acpi_cpu_resume(device_t dev)
413 {
414 
415     cpu_disable_idle = FALSE;
416     return (bus_generic_resume(dev));
417 }
418 
419 /*
420  * Find the nth present CPU and return its pc_cpuid as well as set the
421  * pc_acpi_id from the most reliable source.
422  */
423 static int
424 acpi_pcpu_get_id(uint32_t idx, uint32_t *acpi_id, uint32_t *cpu_id)
425 {
426     struct pcpu	*pcpu_data;
427     uint32_t	 i;
428 
429     KASSERT(acpi_id != NULL, ("Null acpi_id"));
430     KASSERT(cpu_id != NULL, ("Null cpu_id"));
431     for (i = 0; i <= mp_maxid; i++) {
432 	if (CPU_ABSENT(i))
433 	    continue;
434 	pcpu_data = pcpu_find(i);
435 	KASSERT(pcpu_data != NULL, ("no pcpu data for %d", i));
436 	if (idx-- == 0) {
437 	    /*
438 	     * If pc_acpi_id was not initialized (e.g., a non-APIC UP box)
439 	     * override it with the value from the ASL.  Otherwise, if the
440 	     * two don't match, prefer the MADT-derived value.  Finally,
441 	     * return the pc_cpuid to reference this processor.
442 	     */
443 	    if (pcpu_data->pc_acpi_id == 0xffffffff)
444 		pcpu_data->pc_acpi_id = *acpi_id;
445 	    else if (pcpu_data->pc_acpi_id != *acpi_id)
446 		*acpi_id = pcpu_data->pc_acpi_id;
447 	    *cpu_id = pcpu_data->pc_cpuid;
448 	    return (0);
449 	}
450     }
451 
452     return (ESRCH);
453 }
454 
455 static struct resource_list *
456 acpi_cpu_get_rlist(device_t dev, device_t child)
457 {
458     struct acpi_cpu_device *ad;
459 
460     ad = device_get_ivars(child);
461     if (ad == NULL)
462 	return (NULL);
463     return (&ad->ad_rl);
464 }
465 
466 static device_t
467 acpi_cpu_add_child(device_t dev, int order, const char *name, int unit)
468 {
469     struct acpi_cpu_device *ad;
470     device_t child;
471 
472     if ((ad = malloc(sizeof(*ad), M_TEMP, M_NOWAIT | M_ZERO)) == NULL)
473 	return (NULL);
474 
475     resource_list_init(&ad->ad_rl);
476 
477     child = device_add_child_ordered(dev, order, name, unit);
478     if (child != NULL)
479 	device_set_ivars(child, ad);
480     else
481 	free(ad, M_TEMP);
482     return (child);
483 }
484 
485 static int
486 acpi_cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
487 {
488     struct acpi_cpu_softc *sc;
489 
490     sc = device_get_softc(dev);
491     switch (index) {
492     case ACPI_IVAR_HANDLE:
493 	*result = (uintptr_t)sc->cpu_handle;
494 	break;
495     case CPU_IVAR_PCPU:
496 	*result = (uintptr_t)sc->cpu_pcpu;
497 	break;
498     default:
499 	return (ENOENT);
500     }
501     return (0);
502 }
503 
504 static int
505 acpi_cpu_shutdown(device_t dev)
506 {
507     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
508 
509     /* Allow children to shutdown first. */
510     bus_generic_shutdown(dev);
511 
512     /*
513      * Disable any entry to the idle function.  There is a small race where
514      * an idle thread have passed this check but not gone to sleep.  This
515      * is ok since device_shutdown() does not free the softc, otherwise
516      * we'd have to be sure all threads were evicted before returning.
517      */
518     cpu_disable_idle = TRUE;
519 
520     return_VALUE (0);
521 }
522 
523 static void
524 acpi_cpu_cx_probe(struct acpi_cpu_softc *sc)
525 {
526     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
527 
528     /* Use initial sleep value of 1 sec. to start with lowest idle state. */
529     sc->cpu_prev_sleep = 1000000;
530     sc->cpu_cx_lowest = 0;
531 
532     /*
533      * Check for the ACPI 2.0 _CST sleep states object. If we can't find
534      * any, we'll revert to generic FADT/P_BLK Cx control method which will
535      * be handled by acpi_cpu_startup. We need to defer to after having
536      * probed all the cpus in the system before probing for generic Cx
537      * states as we may already have found cpus with valid _CST packages
538      */
539     if (!cpu_cx_generic && acpi_cpu_cx_cst(sc) != 0) {
540 	/*
541 	 * We were unable to find a _CST package for this cpu or there
542 	 * was an error parsing it. Switch back to generic mode.
543 	 */
544 	cpu_cx_generic = TRUE;
545 	if (bootverbose)
546 	    device_printf(sc->cpu_dev, "switching to generic Cx mode\n");
547     }
548 
549     /*
550      * TODO: _CSD Package should be checked here.
551      */
552 }
553 
554 static void
555 acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
556 {
557     ACPI_GENERIC_ADDRESS	 gas;
558     struct acpi_cx		*cx_ptr;
559 
560     sc->cpu_cx_count = 0;
561     cx_ptr = sc->cpu_cx_states;
562 
563     /* Use initial sleep value of 1 sec. to start with lowest idle state. */
564     sc->cpu_prev_sleep = 1000000;
565 
566     /* C1 has been required since just after ACPI 1.0 */
567     cx_ptr->type = ACPI_STATE_C1;
568     cx_ptr->trans_lat = 0;
569     cx_ptr++;
570     sc->cpu_cx_count++;
571 
572     /*
573      * The spec says P_BLK must be 6 bytes long.  However, some systems
574      * use it to indicate a fractional set of features present so we
575      * take 5 as C2.  Some may also have a value of 7 to indicate
576      * another C3 but most use _CST for this (as required) and having
577      * "only" C1-C3 is not a hardship.
578      */
579     if (sc->cpu_p_blk_len < 5)
580 	return;
581 
582     /* Validate and allocate resources for C2 (P_LVL2). */
583     gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
584     gas.BitWidth = 8;
585     if (AcpiGbl_FADT.C2Latency <= 100) {
586 	gas.Address = sc->cpu_p_blk + 4;
587 	acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &sc->cpu_rid,
588 	    &gas, &cx_ptr->p_lvlx, RF_SHAREABLE);
589 	if (cx_ptr->p_lvlx != NULL) {
590 	    sc->cpu_rid++;
591 	    cx_ptr->type = ACPI_STATE_C2;
592 	    cx_ptr->trans_lat = AcpiGbl_FADT.C2Latency;
593 	    cx_ptr++;
594 	    sc->cpu_cx_count++;
595 	}
596     }
597     if (sc->cpu_p_blk_len < 6)
598 	return;
599 
600     /* Validate and allocate resources for C3 (P_LVL3). */
601     if (AcpiGbl_FADT.C3Latency <= 1000 && !(cpu_quirks & CPU_QUIRK_NO_C3)) {
602 	gas.Address = sc->cpu_p_blk + 5;
603 	acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &sc->cpu_rid, &gas,
604 	    &cx_ptr->p_lvlx, RF_SHAREABLE);
605 	if (cx_ptr->p_lvlx != NULL) {
606 	    sc->cpu_rid++;
607 	    cx_ptr->type = ACPI_STATE_C3;
608 	    cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
609 	    cx_ptr++;
610 	    sc->cpu_cx_count++;
611 	}
612     }
613 }
614 
615 /*
616  * Parse a _CST package and set up its Cx states.  Since the _CST object
617  * can change dynamically, our notify handler may call this function
618  * to clean up and probe the new _CST package.
619  */
620 static int
621 acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
622 {
623     struct	 acpi_cx *cx_ptr;
624     ACPI_STATUS	 status;
625     ACPI_BUFFER	 buf;
626     ACPI_OBJECT	*top;
627     ACPI_OBJECT	*pkg;
628     uint32_t	 count;
629     int		 i;
630 
631     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
632 
633     buf.Pointer = NULL;
634     buf.Length = ACPI_ALLOCATE_BUFFER;
635     status = AcpiEvaluateObject(sc->cpu_handle, "_CST", NULL, &buf);
636     if (ACPI_FAILURE(status))
637 	return (ENXIO);
638 
639     /* _CST is a package with a count and at least one Cx package. */
640     top = (ACPI_OBJECT *)buf.Pointer;
641     if (!ACPI_PKG_VALID(top, 2) || acpi_PkgInt32(top, 0, &count) != 0) {
642 	device_printf(sc->cpu_dev, "invalid _CST package\n");
643 	AcpiOsFree(buf.Pointer);
644 	return (ENXIO);
645     }
646     if (count != top->Package.Count - 1) {
647 	device_printf(sc->cpu_dev, "invalid _CST state count (%d != %d)\n",
648 	       count, top->Package.Count - 1);
649 	count = top->Package.Count - 1;
650     }
651     if (count > MAX_CX_STATES) {
652 	device_printf(sc->cpu_dev, "_CST has too many states (%d)\n", count);
653 	count = MAX_CX_STATES;
654     }
655 
656     /* Set up all valid states. */
657     sc->cpu_cx_count = 0;
658     cx_ptr = sc->cpu_cx_states;
659     for (i = 0; i < count; i++) {
660 	pkg = &top->Package.Elements[i + 1];
661 	if (!ACPI_PKG_VALID(pkg, 4) ||
662 	    acpi_PkgInt32(pkg, 1, &cx_ptr->type) != 0 ||
663 	    acpi_PkgInt32(pkg, 2, &cx_ptr->trans_lat) != 0 ||
664 	    acpi_PkgInt32(pkg, 3, &cx_ptr->power) != 0) {
665 
666 	    device_printf(sc->cpu_dev, "skipping invalid Cx state package\n");
667 	    continue;
668 	}
669 
670 	/* Validate the state to see if we should use it. */
671 	switch (cx_ptr->type) {
672 	case ACPI_STATE_C1:
673 	    sc->cpu_non_c3 = i;
674 	    cx_ptr++;
675 	    sc->cpu_cx_count++;
676 	    continue;
677 	case ACPI_STATE_C2:
678 	    if (cx_ptr->trans_lat > 100) {
679 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
680 				 "acpi_cpu%d: C2[%d] not available.\n",
681 				 device_get_unit(sc->cpu_dev), i));
682 		continue;
683 	    }
684 	    sc->cpu_non_c3 = i;
685 	    break;
686 	case ACPI_STATE_C3:
687 	default:
688 	    if (cx_ptr->trans_lat > 1000 ||
689 		(cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
690 
691 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
692 				 "acpi_cpu%d: C3[%d] not available.\n",
693 				 device_get_unit(sc->cpu_dev), i));
694 		continue;
695 	    }
696 	    break;
697 	}
698 
699 #ifdef notyet
700 	/* Free up any previous register. */
701 	if (cx_ptr->p_lvlx != NULL) {
702 	    bus_release_resource(sc->cpu_dev, 0, 0, cx_ptr->p_lvlx);
703 	    cx_ptr->p_lvlx = NULL;
704 	}
705 #endif
706 
707 	/* Allocate the control register for C2 or C3. */
708 	acpi_PkgGas(sc->cpu_dev, pkg, 0, &cx_ptr->res_type, &sc->cpu_rid,
709 	    &cx_ptr->p_lvlx, RF_SHAREABLE);
710 	if (cx_ptr->p_lvlx) {
711 	    sc->cpu_rid++;
712 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
713 			     "acpi_cpu%d: Got C%d - %d latency\n",
714 			     device_get_unit(sc->cpu_dev), cx_ptr->type,
715 			     cx_ptr->trans_lat));
716 	    cx_ptr++;
717 	    sc->cpu_cx_count++;
718 	}
719     }
720     AcpiOsFree(buf.Pointer);
721 
722     return (0);
723 }
724 
725 /*
726  * Call this *after* all CPUs have been attached.
727  */
728 static void
729 acpi_cpu_startup(void *arg)
730 {
731     struct acpi_cpu_softc *sc;
732     int i;
733 
734     /* Get set of CPU devices */
735     newbus_slock();
736     devclass_get_devices(acpi_cpu_devclass, &cpu_devices, &cpu_ndevices);
737     newbus_sunlock();
738 
739     /*
740      * Setup any quirks that might necessary now that we have probed
741      * all the CPUs
742      */
743     acpi_cpu_quirks();
744 
745     cpu_cx_count = 0;
746     if (cpu_cx_generic) {
747 	/*
748 	 * We are using generic Cx mode, probe for available Cx states
749 	 * for all processors.
750 	 */
751 	for (i = 0; i < cpu_ndevices; i++) {
752 	    sc = device_get_softc(cpu_devices[i]);
753 	    acpi_cpu_generic_cx_probe(sc);
754 	    if (sc->cpu_cx_count > cpu_cx_count)
755 		    cpu_cx_count = sc->cpu_cx_count;
756 	}
757 
758 	/*
759 	 * Find the highest Cx state common to all CPUs
760 	 * in the system, taking quirks into account.
761 	 */
762 	for (i = 0; i < cpu_ndevices; i++) {
763 	    sc = device_get_softc(cpu_devices[i]);
764 	    if (sc->cpu_cx_count < cpu_cx_count)
765 		cpu_cx_count = sc->cpu_cx_count;
766 	}
767     } else {
768 	/*
769 	 * We are using _CST mode, remove C3 state if necessary.
770 	 * Update the largest Cx state supported in the global cpu_cx_count.
771 	 * It will be used in the global Cx sysctl handler.
772 	 * As we now know for sure that we will be using _CST mode
773 	 * install our notify handler.
774 	 */
775 	for (i = 0; i < cpu_ndevices; i++) {
776 	    sc = device_get_softc(cpu_devices[i]);
777 	    if (cpu_quirks & CPU_QUIRK_NO_C3) {
778 		sc->cpu_cx_count = sc->cpu_non_c3 + 1;
779 	    }
780 	    if (sc->cpu_cx_count > cpu_cx_count)
781 		cpu_cx_count = sc->cpu_cx_count;
782 	    AcpiInstallNotifyHandler(sc->cpu_handle, ACPI_DEVICE_NOTIFY,
783 		acpi_cpu_notify, sc);
784 	}
785     }
786 
787     /* Perform Cx final initialization. */
788     for (i = 0; i < cpu_ndevices; i++) {
789 	sc = device_get_softc(cpu_devices[i]);
790 	acpi_cpu_startup_cx(sc);
791     }
792 
793     /* Add a sysctl handler to handle global Cx lowest setting */
794     SYSCTL_ADD_PROC(&cpu_sysctl_ctx, SYSCTL_CHILDREN(cpu_sysctl_tree),
795 	OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
796 	NULL, 0, acpi_cpu_global_cx_lowest_sysctl, "A",
797 	"Global lowest Cx sleep state to use");
798 
799     /* Take over idling from cpu_idle_default(). */
800     cpu_cx_lowest = 0;
801     cpu_disable_idle = FALSE;
802     cpu_idle_hook = acpi_cpu_idle;
803 }
804 
805 static void
806 acpi_cpu_cx_list(struct acpi_cpu_softc *sc)
807 {
808     struct sbuf sb;
809     int i;
810 
811     /*
812      * Set up the list of Cx states
813      */
814     sc->cpu_non_c3 = 0;
815     sbuf_new(&sb, sc->cpu_cx_supported, sizeof(sc->cpu_cx_supported),
816 	SBUF_FIXEDLEN);
817     for (i = 0; i < sc->cpu_cx_count; i++) {
818 	sbuf_printf(&sb, "C%d/%d ", i + 1, sc->cpu_cx_states[i].trans_lat);
819 	if (sc->cpu_cx_states[i].type < ACPI_STATE_C3)
820 	    sc->cpu_non_c3 = i;
821     }
822     sbuf_trim(&sb);
823     sbuf_finish(&sb);
824 }
825 
826 static void
827 acpi_cpu_startup_cx(struct acpi_cpu_softc *sc)
828 {
829     acpi_cpu_cx_list(sc);
830 
831     SYSCTL_ADD_STRING(&sc->cpu_sysctl_ctx,
832 		      SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
833 		      OID_AUTO, "cx_supported", CTLFLAG_RD,
834 		      sc->cpu_cx_supported, 0,
835 		      "Cx/microsecond values for supported Cx states");
836     SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
837 		    SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
838 		    OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
839 		    (void *)sc, 0, acpi_cpu_cx_lowest_sysctl, "A",
840 		    "lowest Cx sleep state to use");
841     SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
842 		    SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
843 		    OID_AUTO, "cx_usage", CTLTYPE_STRING | CTLFLAG_RD,
844 		    (void *)sc, 0, acpi_cpu_usage_sysctl, "A",
845 		    "percent usage for each Cx state");
846 
847 #ifdef notyet
848     /* Signal platform that we can handle _CST notification. */
849     if (!cpu_cx_generic && cpu_cst_cnt != 0) {
850 	ACPI_LOCK(acpi);
851 	AcpiOsWritePort(cpu_smi_cmd, cpu_cst_cnt, 8);
852 	ACPI_UNLOCK(acpi);
853     }
854 #endif
855 }
856 
857 /*
858  * Idle the CPU in the lowest state possible.  This function is called with
859  * interrupts disabled.  Note that once it re-enables interrupts, a task
860  * switch can occur so do not access shared data (i.e. the softc) after
861  * interrupts are re-enabled.
862  */
863 static void
864 acpi_cpu_idle()
865 {
866     struct	acpi_cpu_softc *sc;
867     struct	acpi_cx *cx_next;
868     uint32_t	start_time, end_time;
869     int		bm_active, cx_next_idx, i;
870 
871     /* If disabled, return immediately. */
872     if (cpu_disable_idle) {
873 	ACPI_ENABLE_IRQS();
874 	return;
875     }
876 
877     /*
878      * Look up our CPU id to get our softc.  If it's NULL, we'll use C1
879      * since there is no ACPI processor object for this CPU.  This occurs
880      * for logical CPUs in the HTT case.
881      */
882     sc = cpu_softc[PCPU_GET(cpuid)];
883     if (sc == NULL) {
884 	acpi_cpu_c1();
885 	return;
886     }
887 
888     /* Find the lowest state that has small enough latency. */
889     cx_next_idx = 0;
890     for (i = sc->cpu_cx_lowest; i >= 0; i--) {
891 	if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
892 	    cx_next_idx = i;
893 	    break;
894 	}
895     }
896 
897     /*
898      * Check for bus master activity.  If there was activity, clear
899      * the bit and use the lowest non-C3 state.  Note that the USB
900      * driver polling for new devices keeps this bit set all the
901      * time if USB is loaded.
902      */
903     if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
904 	AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
905 	if (bm_active != 0) {
906 	    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
907 	    cx_next_idx = min(cx_next_idx, sc->cpu_non_c3);
908 	}
909     }
910 
911     /* Select the next state and update statistics. */
912     cx_next = &sc->cpu_cx_states[cx_next_idx];
913     sc->cpu_cx_stats[cx_next_idx]++;
914     KASSERT(cx_next->type != ACPI_STATE_C0, ("acpi_cpu_idle: C0 sleep"));
915 
916     /*
917      * Execute HLT (or equivalent) and wait for an interrupt.  We can't
918      * calculate the time spent in C1 since the place we wake up is an
919      * ISR.  Assume we slept half of quantum and return.
920      */
921     if (cx_next->type == ACPI_STATE_C1) {
922 	sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + 500000 / hz) / 4;
923 	acpi_cpu_c1();
924 	return;
925     }
926 
927     /*
928      * For C3, disable bus master arbitration and enable bus master wake
929      * if BM control is available, otherwise flush the CPU cache.
930      */
931     if (cx_next->type == ACPI_STATE_C3) {
932 	if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
933 	    AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 1);
934 	    AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
935 	} else
936 	    ACPI_FLUSH_CPU_CACHE();
937     }
938 
939     /*
940      * Read from P_LVLx to enter C2(+), checking time spent asleep.
941      * Use the ACPI timer for measuring sleep time.  Since we need to
942      * get the time very close to the CPU start/stop clock logic, this
943      * is the only reliable time source.
944      */
945     AcpiRead(&start_time, &AcpiGbl_FADT.XPmTimerBlock);
946     CPU_GET_REG(cx_next->p_lvlx, 1);
947 
948     /*
949      * Read the end time twice.  Since it may take an arbitrary time
950      * to enter the idle state, the first read may be executed before
951      * the processor has stopped.  Doing it again provides enough
952      * margin that we are certain to have a correct value.
953      */
954     AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
955     AcpiRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
956 
957     /* Enable bus master arbitration and disable bus master wakeup. */
958     if (cx_next->type == ACPI_STATE_C3 &&
959 	(cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
960 	AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 0);
961 	AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
962     }
963     ACPI_ENABLE_IRQS();
964 
965     /* Find the actual time asleep in microseconds. */
966     end_time = acpi_TimerDelta(end_time, start_time);
967     sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + PM_USEC(end_time)) / 4;
968 }
969 
970 /*
971  * Re-evaluate the _CST object when we are notified that it changed.
972  *
973  * XXX Re-evaluation disabled until locking is done.
974  */
975 static void
976 acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context)
977 {
978     struct acpi_cpu_softc *sc = (struct acpi_cpu_softc *)context;
979     struct acpi_cpu_softc *isc;
980     int i;
981 
982     if (notify != ACPI_NOTIFY_CX_STATES)
983 	return;
984 
985     /* Update the list of Cx states. */
986     acpi_cpu_cx_cst(sc);
987     acpi_cpu_cx_list(sc);
988 
989     /* Update the new lowest useable Cx state for all CPUs. */
990     ACPI_SERIAL_BEGIN(cpu);
991     cpu_cx_count = 0;
992     for (i = 0; i < cpu_ndevices; i++) {
993 	isc = device_get_softc(cpu_devices[i]);
994 	if (isc->cpu_cx_count > cpu_cx_count)
995 	    cpu_cx_count = isc->cpu_cx_count;
996     }
997     ACPI_SERIAL_END(cpu);
998 }
999 
1000 static int
1001 acpi_cpu_quirks(void)
1002 {
1003     device_t acpi_dev;
1004     uint32_t val;
1005 
1006     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
1007 
1008     /*
1009      * Bus mastering arbitration control is needed to keep caches coherent
1010      * while sleeping in C3.  If it's not present but a working flush cache
1011      * instruction is present, flush the caches before entering C3 instead.
1012      * Otherwise, just disable C3 completely.
1013      */
1014     if (AcpiGbl_FADT.Pm2ControlBlock == 0 ||
1015 	AcpiGbl_FADT.Pm2ControlLength == 0) {
1016 	if ((AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD) &&
1017 	    (AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD_FLUSH) == 0) {
1018 	    cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
1019 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1020 		"acpi_cpu: no BM control, using flush cache method\n"));
1021 	} else {
1022 	    cpu_quirks |= CPU_QUIRK_NO_C3;
1023 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1024 		"acpi_cpu: no BM control, C3 not available\n"));
1025 	}
1026     }
1027 
1028     /*
1029      * If we are using generic Cx mode, C3 on multiple CPUs requires using
1030      * the expensive flush cache instruction.
1031      */
1032     if (cpu_cx_generic && mp_ncpus > 1) {
1033 	cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
1034 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1035 	    "acpi_cpu: SMP, using flush cache mode for C3\n"));
1036     }
1037 
1038     /* Look for various quirks of the PIIX4 part. */
1039     acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
1040     if (acpi_dev != NULL) {
1041 	switch (pci_get_revid(acpi_dev)) {
1042 	/*
1043 	 * Disable C3 support for all PIIX4 chipsets.  Some of these parts
1044 	 * do not report the BMIDE status to the BM status register and
1045 	 * others have a livelock bug if Type-F DMA is enabled.  Linux
1046 	 * works around the BMIDE bug by reading the BM status directly
1047 	 * but we take the simpler approach of disabling C3 for these
1048 	 * parts.
1049 	 *
1050 	 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
1051 	 * Livelock") from the January 2002 PIIX4 specification update.
1052 	 * Applies to all PIIX4 models.
1053 	 *
1054 	 * Also, make sure that all interrupts cause a "Stop Break"
1055 	 * event to exit from C2 state.
1056 	 * Also, BRLD_EN_BM (ACPI_BITREG_BUS_MASTER_RLD in ACPI-speak)
1057 	 * should be set to zero, otherwise it causes C2 to short-sleep.
1058 	 * PIIX4 doesn't properly support C3 and bus master activity
1059 	 * need not break out of C2.
1060 	 */
1061 	case PCI_REVISION_A_STEP:
1062 	case PCI_REVISION_B_STEP:
1063 	case PCI_REVISION_4E:
1064 	case PCI_REVISION_4M:
1065 	    cpu_quirks |= CPU_QUIRK_NO_C3;
1066 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1067 		"acpi_cpu: working around PIIX4 bug, disabling C3\n"));
1068 
1069 	    val = pci_read_config(acpi_dev, PIIX4_DEVACTB_REG, 4);
1070 	    if ((val & PIIX4_STOP_BREAK_MASK) != PIIX4_STOP_BREAK_MASK) {
1071 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1072 		    "acpi_cpu: PIIX4: enabling IRQs to generate Stop Break\n"));
1073 	    	val |= PIIX4_STOP_BREAK_MASK;
1074 		pci_write_config(acpi_dev, PIIX4_DEVACTB_REG, val, 4);
1075 	    }
1076 	    AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_RLD, &val);
1077 	    if (val) {
1078 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1079 		    "acpi_cpu: PIIX4: reset BRLD_EN_BM\n"));
1080 		AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
1081 	    }
1082 	    break;
1083 	default:
1084 	    break;
1085 	}
1086     }
1087 
1088     return (0);
1089 }
1090 
1091 static int
1092 acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS)
1093 {
1094     struct acpi_cpu_softc *sc;
1095     struct sbuf	 sb;
1096     char	 buf[128];
1097     int		 i;
1098     uintmax_t	 fract, sum, whole;
1099 
1100     sc = (struct acpi_cpu_softc *) arg1;
1101     sum = 0;
1102     for (i = 0; i < sc->cpu_cx_count; i++)
1103 	sum += sc->cpu_cx_stats[i];
1104     sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
1105     for (i = 0; i < sc->cpu_cx_count; i++) {
1106 	if (sum > 0) {
1107 	    whole = (uintmax_t)sc->cpu_cx_stats[i] * 100;
1108 	    fract = (whole % sum) * 100;
1109 	    sbuf_printf(&sb, "%u.%02u%% ", (u_int)(whole / sum),
1110 		(u_int)(fract / sum));
1111 	} else
1112 	    sbuf_printf(&sb, "0.00%% ");
1113     }
1114     sbuf_printf(&sb, "last %dus", sc->cpu_prev_sleep);
1115     sbuf_trim(&sb);
1116     sbuf_finish(&sb);
1117     sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
1118     sbuf_delete(&sb);
1119 
1120     return (0);
1121 }
1122 
1123 static int
1124 acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val)
1125 {
1126     int i;
1127 
1128     ACPI_SERIAL_ASSERT(cpu);
1129     sc->cpu_cx_lowest = val;
1130 
1131     /* If not disabling, cache the new lowest non-C3 state. */
1132     sc->cpu_non_c3 = 0;
1133     for (i = sc->cpu_cx_lowest; i >= 0; i--) {
1134 	if (sc->cpu_cx_states[i].type < ACPI_STATE_C3) {
1135 	    sc->cpu_non_c3 = i;
1136 	    break;
1137 	}
1138     }
1139 
1140     /* Reset the statistics counters. */
1141     bzero(sc->cpu_cx_stats, sizeof(sc->cpu_cx_stats));
1142     return (0);
1143 }
1144 
1145 static int
1146 acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
1147 {
1148     struct	 acpi_cpu_softc *sc;
1149     char	 state[8];
1150     int		 val, error;
1151 
1152     sc = (struct acpi_cpu_softc *) arg1;
1153     snprintf(state, sizeof(state), "C%d", sc->cpu_cx_lowest + 1);
1154     error = sysctl_handle_string(oidp, state, sizeof(state), req);
1155     if (error != 0 || req->newptr == NULL)
1156 	return (error);
1157     if (strlen(state) < 2 || toupper(state[0]) != 'C')
1158 	return (EINVAL);
1159     val = (int) strtol(state + 1, NULL, 10) - 1;
1160     if (val < 0 || val > sc->cpu_cx_count - 1)
1161 	return (EINVAL);
1162 
1163     ACPI_SERIAL_BEGIN(cpu);
1164     acpi_cpu_set_cx_lowest(sc, val);
1165     ACPI_SERIAL_END(cpu);
1166 
1167     return (0);
1168 }
1169 
1170 static int
1171 acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
1172 {
1173     struct	acpi_cpu_softc *sc;
1174     char	state[8];
1175     int		val, error, i;
1176 
1177     snprintf(state, sizeof(state), "C%d", cpu_cx_lowest + 1);
1178     error = sysctl_handle_string(oidp, state, sizeof(state), req);
1179     if (error != 0 || req->newptr == NULL)
1180 	return (error);
1181     if (strlen(state) < 2 || toupper(state[0]) != 'C')
1182 	return (EINVAL);
1183     val = (int) strtol(state + 1, NULL, 10) - 1;
1184     if (val < 0 || val > cpu_cx_count - 1)
1185 	return (EINVAL);
1186     cpu_cx_lowest = val;
1187 
1188     /* Update the new lowest useable Cx state for all CPUs. */
1189     ACPI_SERIAL_BEGIN(cpu);
1190     for (i = 0; i < cpu_ndevices; i++) {
1191 	sc = device_get_softc(cpu_devices[i]);
1192 	acpi_cpu_set_cx_lowest(sc, val);
1193     }
1194     ACPI_SERIAL_END(cpu);
1195 
1196     return (0);
1197 }
1198