xref: /freebsd/sys/dev/acpica/acpi_cpu.c (revision f4f8f02054f3abb6ceb84aefcdecc78d5c8b462f)
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/acpi.h>
50 #include <dev/acpica/acpivar.h>
51 
52 /*
53  * Support for ACPI Processor devices, including C[1-3] sleep states.
54  */
55 
56 /* Hooks for the ACPI CA debugging infrastructure */
57 #define _COMPONENT	ACPI_PROCESSOR
58 ACPI_MODULE_NAME("PROCESSOR")
59 
60 struct acpi_cx {
61     struct resource	*p_lvlx;	/* Register to read to enter state. */
62     uint32_t		 type;		/* C1-3 (C4 and up treated as C3). */
63     uint32_t		 trans_lat;	/* Transition latency (usec). */
64     uint32_t		 power;		/* Power consumed (mW). */
65     int			 res_type;	/* Resource type for p_lvlx. */
66 };
67 #define MAX_CX_STATES	 8
68 
69 struct acpi_cpu_softc {
70     device_t		 cpu_dev;
71     ACPI_HANDLE		 cpu_handle;
72     struct pcpu		*cpu_pcpu;
73     uint32_t		 cpu_acpi_id;	/* ACPI processor id */
74     uint32_t		 cpu_p_blk;	/* ACPI P_BLK location */
75     uint32_t		 cpu_p_blk_len;	/* P_BLK length (must be 6). */
76     struct acpi_cx	 cpu_cx_states[MAX_CX_STATES];
77     int			 cpu_cx_count;	/* Number of valid Cx states. */
78     int			 cpu_prev_sleep;/* Last idle sleep duration. */
79     int			 cpu_features;	/* Child driver supported features. */
80     /* Runtime state. */
81     int			 cpu_non_c3;	/* Index of lowest non-C3 state. */
82     u_int		 cpu_cx_stats[MAX_CX_STATES];/* Cx usage history. */
83     /* Values for sysctl. */
84     struct sysctl_ctx_list cpu_sysctl_ctx;
85     struct sysctl_oid	*cpu_sysctl_tree;
86     int			 cpu_cx_lowest;
87     char 		 cpu_cx_supported[64];
88     int			 cpu_rid;
89 };
90 
91 struct acpi_cpu_device {
92     struct resource_list	ad_rl;
93 };
94 
95 #define CPU_GET_REG(reg, width) 					\
96     (bus_space_read_ ## width(rman_get_bustag((reg)), 			\
97 		      rman_get_bushandle((reg)), 0))
98 #define CPU_SET_REG(reg, width, val)					\
99     (bus_space_write_ ## width(rman_get_bustag((reg)), 			\
100 		       rman_get_bushandle((reg)), 0, (val)))
101 
102 #define PM_USEC(x)	 ((x) >> 2)	/* ~4 clocks per usec (3.57955 Mhz) */
103 
104 #define ACPI_NOTIFY_CX_STATES	0x81	/* _CST changed. */
105 
106 #define CPU_QUIRK_NO_C3		(1<<0)	/* C3-type states are not usable. */
107 #define CPU_QUIRK_NO_BM_CTRL	(1<<2)	/* No bus mastering control. */
108 
109 #define PCI_VENDOR_INTEL	0x8086
110 #define PCI_DEVICE_82371AB_3	0x7113	/* PIIX4 chipset for quirks. */
111 #define PCI_REVISION_A_STEP	0
112 #define PCI_REVISION_B_STEP	1
113 #define PCI_REVISION_4E		2
114 #define PCI_REVISION_4M		3
115 #define PIIX4_DEVACTB_REG	0x58
116 #define PIIX4_BRLD_EN_IRQ0	(1<<0)
117 #define PIIX4_BRLD_EN_IRQ	(1<<1)
118 #define PIIX4_BRLD_EN_IRQ8	(1<<5)
119 #define PIIX4_STOP_BREAK_MASK	(PIIX4_BRLD_EN_IRQ0 | PIIX4_BRLD_EN_IRQ | PIIX4_BRLD_EN_IRQ8)
120 #define PIIX4_PCNTRL_BST_EN	(1<<10)
121 
122 /* Platform hardware resource information. */
123 static uint32_t		 cpu_smi_cmd;	/* Value to write to SMI_CMD. */
124 static uint8_t		 cpu_cst_cnt;	/* Indicate we are _CST aware. */
125 static int		 cpu_quirks;	/* Indicate any hardware bugs. */
126 
127 /* Runtime state. */
128 static int		 cpu_disable_idle; /* Disable entry to idle function */
129 static int		 cpu_cx_count;	/* Number of valid Cx states */
130 
131 /* Values for sysctl. */
132 static struct sysctl_ctx_list cpu_sysctl_ctx;
133 static struct sysctl_oid *cpu_sysctl_tree;
134 static int		 cpu_cx_generic;
135 static int		 cpu_cx_lowest;
136 
137 static device_t		*cpu_devices;
138 static int		 cpu_ndevices;
139 static struct acpi_cpu_softc **cpu_softc;
140 ACPI_SERIAL_DECL(cpu, "ACPI CPU");
141 
142 static int	acpi_cpu_probe(device_t dev);
143 static int	acpi_cpu_attach(device_t dev);
144 static int	acpi_cpu_suspend(device_t dev);
145 static int	acpi_cpu_resume(device_t dev);
146 static int	acpi_pcpu_get_id(uint32_t idx, uint32_t *acpi_id,
147 		    uint32_t *cpu_id);
148 static struct resource_list *acpi_cpu_get_rlist(device_t dev, device_t child);
149 static device_t	acpi_cpu_add_child(device_t dev, int order, const char *name,
150 		    int unit);
151 static int	acpi_cpu_read_ivar(device_t dev, device_t child, int index,
152 		    uintptr_t *result);
153 static int	acpi_cpu_shutdown(device_t dev);
154 static void	acpi_cpu_cx_probe(struct acpi_cpu_softc *sc);
155 static void	acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc);
156 static int	acpi_cpu_cx_cst(struct acpi_cpu_softc *sc);
157 static void	acpi_cpu_startup(void *arg);
158 static void	acpi_cpu_startup_cx(struct acpi_cpu_softc *sc);
159 static void	acpi_cpu_cx_list(struct acpi_cpu_softc *sc);
160 static void	acpi_cpu_idle(void);
161 static void	acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context);
162 static int	acpi_cpu_quirks(void);
163 static int	acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS);
164 static int	acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val);
165 static int	acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
166 static int	acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
167 
168 static device_method_t acpi_cpu_methods[] = {
169     /* Device interface */
170     DEVMETHOD(device_probe,	acpi_cpu_probe),
171     DEVMETHOD(device_attach,	acpi_cpu_attach),
172     DEVMETHOD(device_detach,	bus_generic_detach),
173     DEVMETHOD(device_shutdown,	acpi_cpu_shutdown),
174     DEVMETHOD(device_suspend,	acpi_cpu_suspend),
175     DEVMETHOD(device_resume,	acpi_cpu_resume),
176 
177     /* Bus interface */
178     DEVMETHOD(bus_add_child,	acpi_cpu_add_child),
179     DEVMETHOD(bus_read_ivar,	acpi_cpu_read_ivar),
180     DEVMETHOD(bus_get_resource_list, acpi_cpu_get_rlist),
181     DEVMETHOD(bus_get_resource,	bus_generic_rl_get_resource),
182     DEVMETHOD(bus_set_resource,	bus_generic_rl_set_resource),
183     DEVMETHOD(bus_alloc_resource, bus_generic_rl_alloc_resource),
184     DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
185     DEVMETHOD(bus_driver_added,	bus_generic_driver_added),
186     DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
187     DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
188     DEVMETHOD(bus_setup_intr,	bus_generic_setup_intr),
189     DEVMETHOD(bus_teardown_intr, bus_generic_teardown_intr),
190 
191     {0, 0}
192 };
193 
194 static driver_t acpi_cpu_driver = {
195     "cpu",
196     acpi_cpu_methods,
197     sizeof(struct acpi_cpu_softc),
198 };
199 
200 static devclass_t acpi_cpu_devclass;
201 DRIVER_MODULE(cpu, acpi, acpi_cpu_driver, acpi_cpu_devclass, 0, 0);
202 MODULE_DEPEND(cpu, acpi, 1, 1, 1);
203 
204 static int
205 acpi_cpu_probe(device_t dev)
206 {
207     int			   acpi_id, cpu_id;
208     ACPI_BUFFER		   buf;
209     ACPI_HANDLE		   handle;
210     ACPI_OBJECT		   *obj;
211     ACPI_STATUS		   status;
212 
213     if (acpi_disabled("cpu") || acpi_get_type(dev) != ACPI_TYPE_PROCESSOR)
214 	return (ENXIO);
215 
216     handle = acpi_get_handle(dev);
217     if (cpu_softc == NULL)
218 	cpu_softc = malloc(sizeof(struct acpi_cpu_softc *) *
219 	    (mp_maxid + 1), M_TEMP /* XXX */, M_WAITOK | M_ZERO);
220 
221     /* Get our Processor object. */
222     buf.Pointer = NULL;
223     buf.Length = ACPI_ALLOCATE_BUFFER;
224     status = AcpiEvaluateObject(handle, NULL, NULL, &buf);
225     if (ACPI_FAILURE(status)) {
226 	device_printf(dev, "probe failed to get Processor obj - %s\n",
227 		      AcpiFormatException(status));
228 	return (ENXIO);
229     }
230     obj = (ACPI_OBJECT *)buf.Pointer;
231     if (obj->Type != ACPI_TYPE_PROCESSOR) {
232 	device_printf(dev, "Processor object has bad type %d\n", obj->Type);
233 	AcpiOsFree(obj);
234 	return (ENXIO);
235     }
236 
237     /*
238      * Find the processor associated with our unit.  We could use the
239      * ProcId as a key, however, some boxes do not have the same values
240      * in their Processor object as the ProcId values in the MADT.
241      */
242     acpi_id = obj->Processor.ProcId;
243     AcpiOsFree(obj);
244     if (acpi_pcpu_get_id(device_get_unit(dev), &acpi_id, &cpu_id) != 0)
245 	return (ENXIO);
246 
247     /*
248      * Check if we already probed this processor.  We scan the bus twice
249      * so it's possible we've already seen this one.
250      */
251     if (cpu_softc[cpu_id] != NULL)
252 	return (ENXIO);
253 
254     /* Mark this processor as in-use and save our derived id for attach. */
255     cpu_softc[cpu_id] = (void *)1;
256     acpi_set_magic(dev, cpu_id);
257     device_set_desc(dev, "ACPI CPU");
258 
259     return (0);
260 }
261 
262 static int
263 acpi_cpu_attach(device_t dev)
264 {
265     ACPI_BUFFER		   buf;
266     ACPI_OBJECT		   arg[4], *obj;
267     ACPI_OBJECT_LIST	   arglist;
268     struct pcpu		   *pcpu_data;
269     struct acpi_cpu_softc *sc;
270     struct acpi_softc	  *acpi_sc;
271     ACPI_STATUS		   status;
272     u_int		   features;
273     int			   cpu_id, drv_count, i;
274     driver_t 		  **drivers;
275     uint32_t		   cap_set[3];
276 
277     /* UUID needed by _OSC evaluation */
278     static uint8_t cpu_oscuuid[16] = { 0x16, 0xA6, 0x77, 0x40, 0x0C, 0x29,
279 				       0xBE, 0x47, 0x9E, 0xBD, 0xD8, 0x70,
280 				       0x58, 0x71, 0x39, 0x53 };
281 
282     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
283 
284     sc = device_get_softc(dev);
285     sc->cpu_dev = dev;
286     sc->cpu_handle = acpi_get_handle(dev);
287     cpu_id = acpi_get_magic(dev);
288     cpu_softc[cpu_id] = sc;
289     pcpu_data = pcpu_find(cpu_id);
290     pcpu_data->pc_device = dev;
291     sc->cpu_pcpu = pcpu_data;
292     cpu_smi_cmd = AcpiGbl_FADT.SmiCommand;
293     cpu_cst_cnt = AcpiGbl_FADT.CstControl;
294 
295     buf.Pointer = NULL;
296     buf.Length = ACPI_ALLOCATE_BUFFER;
297     status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
298     if (ACPI_FAILURE(status)) {
299 	device_printf(dev, "attach failed to get Processor obj - %s\n",
300 		      AcpiFormatException(status));
301 	return (ENXIO);
302     }
303     obj = (ACPI_OBJECT *)buf.Pointer;
304     sc->cpu_p_blk = obj->Processor.PblkAddress;
305     sc->cpu_p_blk_len = obj->Processor.PblkLength;
306     sc->cpu_acpi_id = obj->Processor.ProcId;
307     AcpiOsFree(obj);
308     ACPI_DEBUG_PRINT((ACPI_DB_INFO, "acpi_cpu%d: P_BLK at %#x/%d\n",
309 		     device_get_unit(dev), sc->cpu_p_blk, sc->cpu_p_blk_len));
310 
311     /*
312      * If this is the first cpu we attach, create and initialize the generic
313      * resources that will be used by all acpi cpu devices.
314      */
315     if (device_get_unit(dev) == 0) {
316 	/* Assume we won't be using generic Cx mode by default */
317 	cpu_cx_generic = FALSE;
318 
319 	/* Install hw.acpi.cpu sysctl tree */
320 	acpi_sc = acpi_device_get_parent_softc(dev);
321 	sysctl_ctx_init(&cpu_sysctl_ctx);
322 	cpu_sysctl_tree = SYSCTL_ADD_NODE(&cpu_sysctl_ctx,
323 	    SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree), OID_AUTO, "cpu",
324 	    CTLFLAG_RD, 0, "node for CPU children");
325 
326 	/* Queue post cpu-probing task handler */
327 	AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_cpu_startup, NULL);
328     }
329 
330     /*
331      * Before calling any CPU methods, collect child driver feature hints
332      * and notify ACPI of them.  We support unified SMP power control
333      * so advertise this ourselves.  Note this is not the same as independent
334      * SMP control where each CPU can have different settings.
335      */
336     sc->cpu_features = ACPI_CAP_SMP_SAME | ACPI_CAP_SMP_SAME_C3;
337     if (devclass_get_drivers(acpi_cpu_devclass, &drivers, &drv_count) == 0) {
338 	for (i = 0; i < drv_count; i++) {
339 	    if (ACPI_GET_FEATURES(drivers[i], &features) == 0)
340 		sc->cpu_features |= features;
341 	}
342 	free(drivers, M_TEMP);
343     }
344 
345     /*
346      * CPU capabilities are specified as a buffer of 32-bit integers:
347      * revision, count, and one or more capabilities.  The revision of
348      * "1" is not specified anywhere but seems to match Linux.
349      */
350     if (sc->cpu_features) {
351 	arglist.Pointer = arg;
352 	arglist.Count = 1;
353 	arg[0].Type = ACPI_TYPE_BUFFER;
354 	arg[0].Buffer.Length = sizeof(cap_set);
355 	arg[0].Buffer.Pointer = (uint8_t *)cap_set;
356 	cap_set[0] = 1; /* revision */
357 	cap_set[1] = 1; /* number of capabilities integers */
358 	cap_set[2] = sc->cpu_features;
359 	AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
360 
361 	/*
362 	 * On some systems we need to evaluate _OSC so that the ASL
363 	 * loads the _PSS and/or _PDC methods at runtime.
364 	 *
365 	 * TODO: evaluate failure of _OSC.
366 	 */
367 	arglist.Pointer = arg;
368 	arglist.Count = 4;
369 	arg[0].Type = ACPI_TYPE_BUFFER;
370 	arg[0].Buffer.Length = sizeof(cpu_oscuuid);
371 	arg[0].Buffer.Pointer = cpu_oscuuid;	/* UUID */
372 	arg[1].Type = ACPI_TYPE_INTEGER;
373 	arg[1].Integer.Value = 1;		/* revision */
374 	arg[2].Type = ACPI_TYPE_INTEGER;
375 	arg[2].Integer.Value = 1;		/* count */
376 	arg[3].Type = ACPI_TYPE_BUFFER;
377 	arg[3].Buffer.Length = sizeof(cap_set);	/* Capabilities buffer */
378 	arg[3].Buffer.Pointer = (uint8_t *)cap_set;
379 	cap_set[0] = 0;
380 	AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
381     }
382 
383     /* Probe for Cx state support. */
384     acpi_cpu_cx_probe(sc);
385 
386     /* Finally,  call identify and probe/attach for child devices. */
387     bus_generic_probe(dev);
388     bus_generic_attach(dev);
389 
390     return (0);
391 }
392 
393 /*
394  * Disable any entry to the idle function during suspend and re-enable it
395  * during resume.
396  */
397 static int
398 acpi_cpu_suspend(device_t dev)
399 {
400     int error;
401 
402     error = bus_generic_suspend(dev);
403     if (error)
404 	return (error);
405     cpu_disable_idle = TRUE;
406     return (0);
407 }
408 
409 static int
410 acpi_cpu_resume(device_t dev)
411 {
412 
413     cpu_disable_idle = FALSE;
414     return (bus_generic_resume(dev));
415 }
416 
417 /*
418  * Find the nth present CPU and return its pc_cpuid as well as set the
419  * pc_acpi_id from the most reliable source.
420  */
421 static int
422 acpi_pcpu_get_id(uint32_t idx, uint32_t *acpi_id, uint32_t *cpu_id)
423 {
424     struct pcpu	*pcpu_data;
425     uint32_t	 i;
426 
427     KASSERT(acpi_id != NULL, ("Null acpi_id"));
428     KASSERT(cpu_id != NULL, ("Null cpu_id"));
429     for (i = 0; i <= mp_maxid; i++) {
430 	if (CPU_ABSENT(i))
431 	    continue;
432 	pcpu_data = pcpu_find(i);
433 	KASSERT(pcpu_data != NULL, ("no pcpu data for %d", i));
434 	if (idx-- == 0) {
435 	    /*
436 	     * If pc_acpi_id was not initialized (e.g., a non-APIC UP box)
437 	     * override it with the value from the ASL.  Otherwise, if the
438 	     * two don't match, prefer the MADT-derived value.  Finally,
439 	     * return the pc_cpuid to reference this processor.
440 	     */
441 	    if (pcpu_data->pc_acpi_id == 0xffffffff)
442 		pcpu_data->pc_acpi_id = *acpi_id;
443 	    else if (pcpu_data->pc_acpi_id != *acpi_id)
444 		*acpi_id = pcpu_data->pc_acpi_id;
445 	    *cpu_id = pcpu_data->pc_cpuid;
446 	    return (0);
447 	}
448     }
449 
450     return (ESRCH);
451 }
452 
453 static struct resource_list *
454 acpi_cpu_get_rlist(device_t dev, device_t child)
455 {
456     struct acpi_cpu_device *ad;
457 
458     ad = device_get_ivars(child);
459     if (ad == NULL)
460 	return (NULL);
461     return (&ad->ad_rl);
462 }
463 
464 static device_t
465 acpi_cpu_add_child(device_t dev, int order, const char *name, int unit)
466 {
467     struct acpi_cpu_device *ad;
468     device_t child;
469 
470     if ((ad = malloc(sizeof(*ad), M_TEMP, M_NOWAIT | M_ZERO)) == NULL)
471 	return (NULL);
472 
473     resource_list_init(&ad->ad_rl);
474 
475     child = device_add_child_ordered(dev, order, name, unit);
476     if (child != NULL)
477 	device_set_ivars(child, ad);
478     else
479 	free(ad, M_TEMP);
480     return (child);
481 }
482 
483 static int
484 acpi_cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
485 {
486     struct acpi_cpu_softc *sc;
487 
488     sc = device_get_softc(dev);
489     switch (index) {
490     case ACPI_IVAR_HANDLE:
491 	*result = (uintptr_t)sc->cpu_handle;
492 	break;
493     case CPU_IVAR_PCPU:
494 	*result = (uintptr_t)sc->cpu_pcpu;
495 	break;
496     default:
497 	return (ENOENT);
498     }
499     return (0);
500 }
501 
502 static int
503 acpi_cpu_shutdown(device_t dev)
504 {
505     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
506 
507     /* Allow children to shutdown first. */
508     bus_generic_shutdown(dev);
509 
510     /*
511      * Disable any entry to the idle function.  There is a small race where
512      * an idle thread have passed this check but not gone to sleep.  This
513      * is ok since device_shutdown() does not free the softc, otherwise
514      * we'd have to be sure all threads were evicted before returning.
515      */
516     cpu_disable_idle = TRUE;
517 
518     return_VALUE (0);
519 }
520 
521 static void
522 acpi_cpu_cx_probe(struct acpi_cpu_softc *sc)
523 {
524     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
525 
526     /* Use initial sleep value of 1 sec. to start with lowest idle state. */
527     sc->cpu_prev_sleep = 1000000;
528     sc->cpu_cx_lowest = 0;
529 
530     /*
531      * Check for the ACPI 2.0 _CST sleep states object. If we can't find
532      * any, we'll revert to generic FADT/P_BLK Cx control method which will
533      * be handled by acpi_cpu_startup. We need to defer to after having
534      * probed all the cpus in the system before probing for generic Cx
535      * states as we may already have found cpus with valid _CST packages
536      */
537     if (!cpu_cx_generic && acpi_cpu_cx_cst(sc) != 0) {
538 	/*
539 	 * We were unable to find a _CST package for this cpu or there
540 	 * was an error parsing it. Switch back to generic mode.
541 	 */
542 	cpu_cx_generic = TRUE;
543 	if (bootverbose)
544 	    device_printf(sc->cpu_dev, "switching to generic Cx mode\n");
545     }
546 
547     /*
548      * TODO: _CSD Package should be checked here.
549      */
550 }
551 
552 static void
553 acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
554 {
555     ACPI_GENERIC_ADDRESS	 gas;
556     struct acpi_cx		*cx_ptr;
557 
558     sc->cpu_cx_count = 0;
559     cx_ptr = sc->cpu_cx_states;
560 
561     /* Use initial sleep value of 1 sec. to start with lowest idle state. */
562     sc->cpu_prev_sleep = 1000000;
563 
564     /* C1 has been required since just after ACPI 1.0 */
565     cx_ptr->type = ACPI_STATE_C1;
566     cx_ptr->trans_lat = 0;
567     cx_ptr++;
568     sc->cpu_cx_count++;
569 
570     /*
571      * The spec says P_BLK must be 6 bytes long.  However, some systems
572      * use it to indicate a fractional set of features present so we
573      * take 5 as C2.  Some may also have a value of 7 to indicate
574      * another C3 but most use _CST for this (as required) and having
575      * "only" C1-C3 is not a hardship.
576      */
577     if (sc->cpu_p_blk_len < 5)
578 	return;
579 
580     /* Validate and allocate resources for C2 (P_LVL2). */
581     gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
582     gas.BitWidth = 8;
583     if (AcpiGbl_FADT.C2Latency <= 100) {
584 	gas.Address = sc->cpu_p_blk + 4;
585 	acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &sc->cpu_rid,
586 	    &gas, &cx_ptr->p_lvlx, RF_SHAREABLE);
587 	if (cx_ptr->p_lvlx != NULL) {
588 	    sc->cpu_rid++;
589 	    cx_ptr->type = ACPI_STATE_C2;
590 	    cx_ptr->trans_lat = AcpiGbl_FADT.C2Latency;
591 	    cx_ptr++;
592 	    sc->cpu_cx_count++;
593 	}
594     }
595     if (sc->cpu_p_blk_len < 6)
596 	return;
597 
598     /* Validate and allocate resources for C3 (P_LVL3). */
599     if (AcpiGbl_FADT.C3Latency <= 1000 && !(cpu_quirks & CPU_QUIRK_NO_C3)) {
600 	gas.Address = sc->cpu_p_blk + 5;
601 	acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &sc->cpu_rid, &gas,
602 	    &cx_ptr->p_lvlx, RF_SHAREABLE);
603 	if (cx_ptr->p_lvlx != NULL) {
604 	    sc->cpu_rid++;
605 	    cx_ptr->type = ACPI_STATE_C3;
606 	    cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
607 	    cx_ptr++;
608 	    sc->cpu_cx_count++;
609 	}
610     }
611 }
612 
613 /*
614  * Parse a _CST package and set up its Cx states.  Since the _CST object
615  * can change dynamically, our notify handler may call this function
616  * to clean up and probe the new _CST package.
617  */
618 static int
619 acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
620 {
621     struct	 acpi_cx *cx_ptr;
622     ACPI_STATUS	 status;
623     ACPI_BUFFER	 buf;
624     ACPI_OBJECT	*top;
625     ACPI_OBJECT	*pkg;
626     uint32_t	 count;
627     int		 i;
628 
629     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
630 
631     buf.Pointer = NULL;
632     buf.Length = ACPI_ALLOCATE_BUFFER;
633     status = AcpiEvaluateObject(sc->cpu_handle, "_CST", NULL, &buf);
634     if (ACPI_FAILURE(status))
635 	return (ENXIO);
636 
637     /* _CST is a package with a count and at least one Cx package. */
638     top = (ACPI_OBJECT *)buf.Pointer;
639     if (!ACPI_PKG_VALID(top, 2) || acpi_PkgInt32(top, 0, &count) != 0) {
640 	device_printf(sc->cpu_dev, "invalid _CST package\n");
641 	AcpiOsFree(buf.Pointer);
642 	return (ENXIO);
643     }
644     if (count != top->Package.Count - 1) {
645 	device_printf(sc->cpu_dev, "invalid _CST state count (%d != %d)\n",
646 	       count, top->Package.Count - 1);
647 	count = top->Package.Count - 1;
648     }
649     if (count > MAX_CX_STATES) {
650 	device_printf(sc->cpu_dev, "_CST has too many states (%d)\n", count);
651 	count = MAX_CX_STATES;
652     }
653 
654     /* Set up all valid states. */
655     sc->cpu_cx_count = 0;
656     cx_ptr = sc->cpu_cx_states;
657     for (i = 0; i < count; i++) {
658 	pkg = &top->Package.Elements[i + 1];
659 	if (!ACPI_PKG_VALID(pkg, 4) ||
660 	    acpi_PkgInt32(pkg, 1, &cx_ptr->type) != 0 ||
661 	    acpi_PkgInt32(pkg, 2, &cx_ptr->trans_lat) != 0 ||
662 	    acpi_PkgInt32(pkg, 3, &cx_ptr->power) != 0) {
663 
664 	    device_printf(sc->cpu_dev, "skipping invalid Cx state package\n");
665 	    continue;
666 	}
667 
668 	/* Validate the state to see if we should use it. */
669 	switch (cx_ptr->type) {
670 	case ACPI_STATE_C1:
671 	    sc->cpu_non_c3 = i;
672 	    cx_ptr++;
673 	    sc->cpu_cx_count++;
674 	    continue;
675 	case ACPI_STATE_C2:
676 	    if (cx_ptr->trans_lat > 100) {
677 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
678 				 "acpi_cpu%d: C2[%d] not available.\n",
679 				 device_get_unit(sc->cpu_dev), i));
680 		continue;
681 	    }
682 	    sc->cpu_non_c3 = i;
683 	    break;
684 	case ACPI_STATE_C3:
685 	default:
686 	    if (cx_ptr->trans_lat > 1000 ||
687 		(cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
688 
689 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
690 				 "acpi_cpu%d: C3[%d] not available.\n",
691 				 device_get_unit(sc->cpu_dev), i));
692 		continue;
693 	    }
694 	    break;
695 	}
696 
697 #ifdef notyet
698 	/* Free up any previous register. */
699 	if (cx_ptr->p_lvlx != NULL) {
700 	    bus_release_resource(sc->cpu_dev, 0, 0, cx_ptr->p_lvlx);
701 	    cx_ptr->p_lvlx = NULL;
702 	}
703 #endif
704 
705 	/* Allocate the control register for C2 or C3. */
706 	acpi_PkgGas(sc->cpu_dev, pkg, 0, &cx_ptr->res_type, &sc->cpu_rid,
707 	    &cx_ptr->p_lvlx, RF_SHAREABLE);
708 	if (cx_ptr->p_lvlx) {
709 	    sc->cpu_rid++;
710 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
711 			     "acpi_cpu%d: Got C%d - %d latency\n",
712 			     device_get_unit(sc->cpu_dev), cx_ptr->type,
713 			     cx_ptr->trans_lat));
714 	    cx_ptr++;
715 	    sc->cpu_cx_count++;
716 	}
717     }
718     AcpiOsFree(buf.Pointer);
719 
720     return (0);
721 }
722 
723 /*
724  * Call this *after* all CPUs have been attached.
725  */
726 static void
727 acpi_cpu_startup(void *arg)
728 {
729     struct acpi_cpu_softc *sc;
730     int i;
731 
732     /* Get set of CPU devices */
733     devclass_get_devices(acpi_cpu_devclass, &cpu_devices, &cpu_ndevices);
734 
735     /*
736      * Setup any quirks that might necessary now that we have probed
737      * all the CPUs
738      */
739     acpi_cpu_quirks();
740 
741     cpu_cx_count = 0;
742     if (cpu_cx_generic) {
743 	/*
744 	 * We are using generic Cx mode, probe for available Cx states
745 	 * for all processors.
746 	 */
747 	for (i = 0; i < cpu_ndevices; i++) {
748 	    sc = device_get_softc(cpu_devices[i]);
749 	    acpi_cpu_generic_cx_probe(sc);
750 	    if (sc->cpu_cx_count > cpu_cx_count)
751 		    cpu_cx_count = sc->cpu_cx_count;
752 	}
753 
754 	/*
755 	 * Find the highest Cx state common to all CPUs
756 	 * in the system, taking quirks into account.
757 	 */
758 	for (i = 0; i < cpu_ndevices; i++) {
759 	    sc = device_get_softc(cpu_devices[i]);
760 	    if (sc->cpu_cx_count < cpu_cx_count)
761 		cpu_cx_count = sc->cpu_cx_count;
762 	}
763     } else {
764 	/*
765 	 * We are using _CST mode, remove C3 state if necessary.
766 	 * Update the largest Cx state supported in the global cpu_cx_count.
767 	 * It will be used in the global Cx sysctl handler.
768 	 * As we now know for sure that we will be using _CST mode
769 	 * install our notify handler.
770 	 */
771 	for (i = 0; i < cpu_ndevices; i++) {
772 	    sc = device_get_softc(cpu_devices[i]);
773 	    if (cpu_quirks & CPU_QUIRK_NO_C3) {
774 		sc->cpu_cx_count = sc->cpu_non_c3 + 1;
775 	    }
776 	    if (sc->cpu_cx_count > cpu_cx_count)
777 		cpu_cx_count = sc->cpu_cx_count;
778 	    AcpiInstallNotifyHandler(sc->cpu_handle, ACPI_DEVICE_NOTIFY,
779 		acpi_cpu_notify, sc);
780 	}
781     }
782 
783     /* Perform Cx final initialization. */
784     for (i = 0; i < cpu_ndevices; i++) {
785 	sc = device_get_softc(cpu_devices[i]);
786 	acpi_cpu_startup_cx(sc);
787     }
788 
789     /* Add a sysctl handler to handle global Cx lowest setting */
790     SYSCTL_ADD_PROC(&cpu_sysctl_ctx, SYSCTL_CHILDREN(cpu_sysctl_tree),
791 	OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
792 	NULL, 0, acpi_cpu_global_cx_lowest_sysctl, "A",
793 	"Global lowest Cx sleep state to use");
794 
795     /* Take over idling from cpu_idle_default(). */
796     cpu_cx_lowest = 0;
797     cpu_disable_idle = FALSE;
798     cpu_idle_hook = acpi_cpu_idle;
799 }
800 
801 static void
802 acpi_cpu_cx_list(struct acpi_cpu_softc *sc)
803 {
804     struct sbuf sb;
805     int i;
806 
807     /*
808      * Set up the list of Cx states
809      */
810     sc->cpu_non_c3 = 0;
811     sbuf_new(&sb, sc->cpu_cx_supported, sizeof(sc->cpu_cx_supported),
812 	SBUF_FIXEDLEN);
813     for (i = 0; i < sc->cpu_cx_count; i++) {
814 	sbuf_printf(&sb, "C%d/%d ", i + 1, sc->cpu_cx_states[i].trans_lat);
815 	if (sc->cpu_cx_states[i].type < ACPI_STATE_C3)
816 	    sc->cpu_non_c3 = i;
817     }
818     sbuf_trim(&sb);
819     sbuf_finish(&sb);
820 }
821 
822 static void
823 acpi_cpu_startup_cx(struct acpi_cpu_softc *sc)
824 {
825     acpi_cpu_cx_list(sc);
826 
827     SYSCTL_ADD_STRING(&sc->cpu_sysctl_ctx,
828 		      SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
829 		      OID_AUTO, "cx_supported", CTLFLAG_RD,
830 		      sc->cpu_cx_supported, 0,
831 		      "Cx/microsecond values for supported Cx states");
832     SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
833 		    SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
834 		    OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
835 		    (void *)sc, 0, acpi_cpu_cx_lowest_sysctl, "A",
836 		    "lowest Cx sleep state to use");
837     SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
838 		    SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
839 		    OID_AUTO, "cx_usage", CTLTYPE_STRING | CTLFLAG_RD,
840 		    (void *)sc, 0, acpi_cpu_usage_sysctl, "A",
841 		    "percent usage for each Cx state");
842 
843 #ifdef notyet
844     /* Signal platform that we can handle _CST notification. */
845     if (!cpu_cx_generic && cpu_cst_cnt != 0) {
846 	ACPI_LOCK(acpi);
847 	AcpiOsWritePort(cpu_smi_cmd, cpu_cst_cnt, 8);
848 	ACPI_UNLOCK(acpi);
849     }
850 #endif
851 }
852 
853 /*
854  * Idle the CPU in the lowest state possible.  This function is called with
855  * interrupts disabled.  Note that once it re-enables interrupts, a task
856  * switch can occur so do not access shared data (i.e. the softc) after
857  * interrupts are re-enabled.
858  */
859 static void
860 acpi_cpu_idle()
861 {
862     struct	acpi_cpu_softc *sc;
863     struct	acpi_cx *cx_next;
864     uint32_t	start_time, end_time;
865     int		bm_active, cx_next_idx, i;
866 
867     /* If disabled, return immediately. */
868     if (cpu_disable_idle) {
869 	ACPI_ENABLE_IRQS();
870 	return;
871     }
872 
873     /*
874      * Look up our CPU id to get our softc.  If it's NULL, we'll use C1
875      * since there is no ACPI processor object for this CPU.  This occurs
876      * for logical CPUs in the HTT case.
877      */
878     sc = cpu_softc[PCPU_GET(cpuid)];
879     if (sc == NULL) {
880 	acpi_cpu_c1();
881 	return;
882     }
883 
884     /* Find the lowest state that has small enough latency. */
885     cx_next_idx = 0;
886     for (i = sc->cpu_cx_lowest; i >= 0; i--) {
887 	if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
888 	    cx_next_idx = i;
889 	    break;
890 	}
891     }
892 
893     /*
894      * Check for bus master activity.  If there was activity, clear
895      * the bit and use the lowest non-C3 state.  Note that the USB
896      * driver polling for new devices keeps this bit set all the
897      * time if USB is loaded.
898      */
899     if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
900 	AcpiGetRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
901 	if (bm_active != 0) {
902 	    AcpiSetRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
903 	    cx_next_idx = min(cx_next_idx, sc->cpu_non_c3);
904 	}
905     }
906 
907     /* Select the next state and update statistics. */
908     cx_next = &sc->cpu_cx_states[cx_next_idx];
909     sc->cpu_cx_stats[cx_next_idx]++;
910     KASSERT(cx_next->type != ACPI_STATE_C0, ("acpi_cpu_idle: C0 sleep"));
911 
912     /*
913      * Execute HLT (or equivalent) and wait for an interrupt.  We can't
914      * calculate the time spent in C1 since the place we wake up is an
915      * ISR.  Assume we slept half of quantum and return.
916      */
917     if (cx_next->type == ACPI_STATE_C1) {
918 	sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + 500000 / hz) / 4;
919 	acpi_cpu_c1();
920 	return;
921     }
922 
923     /*
924      * For C3, disable bus master arbitration and enable bus master wake
925      * if BM control is available, otherwise flush the CPU cache.
926      */
927     if (cx_next->type == ACPI_STATE_C3) {
928 	if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
929 	    AcpiSetRegister(ACPI_BITREG_ARB_DISABLE, 1);
930 	    AcpiSetRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
931 	} else
932 	    ACPI_FLUSH_CPU_CACHE();
933     }
934 
935     /*
936      * Read from P_LVLx to enter C2(+), checking time spent asleep.
937      * Use the ACPI timer for measuring sleep time.  Since we need to
938      * get the time very close to the CPU start/stop clock logic, this
939      * is the only reliable time source.
940      */
941     AcpiHwLowLevelRead(32, &start_time, &AcpiGbl_FADT.XPmTimerBlock);
942     CPU_GET_REG(cx_next->p_lvlx, 1);
943 
944     /*
945      * Read the end time twice.  Since it may take an arbitrary time
946      * to enter the idle state, the first read may be executed before
947      * the processor has stopped.  Doing it again provides enough
948      * margin that we are certain to have a correct value.
949      */
950     AcpiHwLowLevelRead(32, &end_time, &AcpiGbl_FADT.XPmTimerBlock);
951     AcpiHwLowLevelRead(32, &end_time, &AcpiGbl_FADT.XPmTimerBlock);
952 
953     /* Enable bus master arbitration and disable bus master wakeup. */
954     if (cx_next->type == ACPI_STATE_C3 &&
955 	(cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
956 	AcpiSetRegister(ACPI_BITREG_ARB_DISABLE, 0);
957 	AcpiSetRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
958     }
959     ACPI_ENABLE_IRQS();
960 
961     /* Find the actual time asleep in microseconds. */
962     end_time = acpi_TimerDelta(end_time, start_time);
963     sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + PM_USEC(end_time)) / 4;
964 }
965 
966 /*
967  * Re-evaluate the _CST object when we are notified that it changed.
968  *
969  * XXX Re-evaluation disabled until locking is done.
970  */
971 static void
972 acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context)
973 {
974     struct acpi_cpu_softc *sc = (struct acpi_cpu_softc *)context;
975     struct acpi_cpu_softc *isc;
976     int i;
977 
978     if (notify != ACPI_NOTIFY_CX_STATES)
979 	return;
980 
981     /* Update the list of Cx states. */
982     acpi_cpu_cx_cst(sc);
983     acpi_cpu_cx_list(sc);
984 
985     /* Update the new lowest useable Cx state for all CPUs. */
986     ACPI_SERIAL_BEGIN(cpu);
987     cpu_cx_count = 0;
988     for (i = 0; i < cpu_ndevices; i++) {
989 	isc = device_get_softc(cpu_devices[i]);
990 	if (isc->cpu_cx_count > cpu_cx_count)
991 	    cpu_cx_count = isc->cpu_cx_count;
992     }
993     ACPI_SERIAL_END(cpu);
994 }
995 
996 static int
997 acpi_cpu_quirks(void)
998 {
999     device_t acpi_dev;
1000     uint32_t val;
1001 
1002     ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
1003 
1004     /*
1005      * Bus mastering arbitration control is needed to keep caches coherent
1006      * while sleeping in C3.  If it's not present but a working flush cache
1007      * instruction is present, flush the caches before entering C3 instead.
1008      * Otherwise, just disable C3 completely.
1009      */
1010     if (AcpiGbl_FADT.Pm2ControlBlock == 0 ||
1011 	AcpiGbl_FADT.Pm2ControlLength == 0) {
1012 	if ((AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD) &&
1013 	    (AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD_FLUSH) == 0) {
1014 	    cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
1015 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1016 		"acpi_cpu: no BM control, using flush cache method\n"));
1017 	} else {
1018 	    cpu_quirks |= CPU_QUIRK_NO_C3;
1019 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1020 		"acpi_cpu: no BM control, C3 not available\n"));
1021 	}
1022     }
1023 
1024     /*
1025      * If we are using generic Cx mode, C3 on multiple CPUs requires using
1026      * the expensive flush cache instruction.
1027      */
1028     if (cpu_cx_generic && mp_ncpus > 1) {
1029 	cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
1030 	ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1031 	    "acpi_cpu: SMP, using flush cache mode for C3\n"));
1032     }
1033 
1034     /* Look for various quirks of the PIIX4 part. */
1035     acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
1036     if (acpi_dev != NULL) {
1037 	switch (pci_get_revid(acpi_dev)) {
1038 	/*
1039 	 * Disable C3 support for all PIIX4 chipsets.  Some of these parts
1040 	 * do not report the BMIDE status to the BM status register and
1041 	 * others have a livelock bug if Type-F DMA is enabled.  Linux
1042 	 * works around the BMIDE bug by reading the BM status directly
1043 	 * but we take the simpler approach of disabling C3 for these
1044 	 * parts.
1045 	 *
1046 	 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
1047 	 * Livelock") from the January 2002 PIIX4 specification update.
1048 	 * Applies to all PIIX4 models.
1049 	 *
1050 	 * Also, make sure that all interrupts cause a "Stop Break"
1051 	 * event to exit from C2 state.
1052 	 * Also, BRLD_EN_BM (ACPI_BITREG_BUS_MASTER_RLD in ACPI-speak)
1053 	 * should be set to zero, otherwise it causes C2 to short-sleep.
1054 	 * PIIX4 doesn't properly support C3 and bus master activity
1055 	 * need not break out of C2.
1056 	 */
1057 	case PCI_REVISION_A_STEP:
1058 	case PCI_REVISION_B_STEP:
1059 	case PCI_REVISION_4E:
1060 	case PCI_REVISION_4M:
1061 	    cpu_quirks |= CPU_QUIRK_NO_C3;
1062 	    ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1063 		"acpi_cpu: working around PIIX4 bug, disabling C3\n"));
1064 
1065 	    val = pci_read_config(acpi_dev, PIIX4_DEVACTB_REG, 4);
1066 	    if ((val & PIIX4_STOP_BREAK_MASK) != PIIX4_STOP_BREAK_MASK) {
1067 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1068 		    "acpi_cpu: PIIX4: enabling IRQs to generate Stop Break\n"));
1069 	    	val |= PIIX4_STOP_BREAK_MASK;
1070 		pci_write_config(acpi_dev, PIIX4_DEVACTB_REG, val, 4);
1071 	    }
1072 	    AcpiGetRegister(ACPI_BITREG_BUS_MASTER_RLD, &val);
1073 	    if (val) {
1074 		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
1075 		    "acpi_cpu: PIIX4: reset BRLD_EN_BM\n"));
1076 		AcpiSetRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
1077 	    }
1078 	    break;
1079 	default:
1080 	    break;
1081 	}
1082     }
1083 
1084     return (0);
1085 }
1086 
1087 static int
1088 acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS)
1089 {
1090     struct acpi_cpu_softc *sc;
1091     struct sbuf	 sb;
1092     char	 buf[128];
1093     int		 i;
1094     uintmax_t	 fract, sum, whole;
1095 
1096     sc = (struct acpi_cpu_softc *) arg1;
1097     sum = 0;
1098     for (i = 0; i < sc->cpu_cx_count; i++)
1099 	sum += sc->cpu_cx_stats[i];
1100     sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
1101     for (i = 0; i < sc->cpu_cx_count; i++) {
1102 	if (sum > 0) {
1103 	    whole = (uintmax_t)sc->cpu_cx_stats[i] * 100;
1104 	    fract = (whole % sum) * 100;
1105 	    sbuf_printf(&sb, "%u.%02u%% ", (u_int)(whole / sum),
1106 		(u_int)(fract / sum));
1107 	} else
1108 	    sbuf_printf(&sb, "0.00%% ");
1109     }
1110     sbuf_printf(&sb, "last %dus", sc->cpu_prev_sleep);
1111     sbuf_trim(&sb);
1112     sbuf_finish(&sb);
1113     sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
1114     sbuf_delete(&sb);
1115 
1116     return (0);
1117 }
1118 
1119 static int
1120 acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc, int val)
1121 {
1122     int i;
1123 
1124     ACPI_SERIAL_ASSERT(cpu);
1125     sc->cpu_cx_lowest = val;
1126 
1127     /* If not disabling, cache the new lowest non-C3 state. */
1128     sc->cpu_non_c3 = 0;
1129     for (i = sc->cpu_cx_lowest; i >= 0; i--) {
1130 	if (sc->cpu_cx_states[i].type < ACPI_STATE_C3) {
1131 	    sc->cpu_non_c3 = i;
1132 	    break;
1133 	}
1134     }
1135 
1136     /* Reset the statistics counters. */
1137     bzero(sc->cpu_cx_stats, sizeof(sc->cpu_cx_stats));
1138     return (0);
1139 }
1140 
1141 static int
1142 acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
1143 {
1144     struct	 acpi_cpu_softc *sc;
1145     char	 state[8];
1146     int		 val, error;
1147 
1148     sc = (struct acpi_cpu_softc *) arg1;
1149     snprintf(state, sizeof(state), "C%d", sc->cpu_cx_lowest + 1);
1150     error = sysctl_handle_string(oidp, state, sizeof(state), req);
1151     if (error != 0 || req->newptr == NULL)
1152 	return (error);
1153     if (strlen(state) < 2 || toupper(state[0]) != 'C')
1154 	return (EINVAL);
1155     val = (int) strtol(state + 1, NULL, 10) - 1;
1156     if (val < 0 || val > sc->cpu_cx_count - 1)
1157 	return (EINVAL);
1158 
1159     ACPI_SERIAL_BEGIN(cpu);
1160     acpi_cpu_set_cx_lowest(sc, val);
1161     ACPI_SERIAL_END(cpu);
1162 
1163     return (0);
1164 }
1165 
1166 static int
1167 acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
1168 {
1169     struct	acpi_cpu_softc *sc;
1170     char	state[8];
1171     int		val, error, i;
1172 
1173     snprintf(state, sizeof(state), "C%d", cpu_cx_lowest + 1);
1174     error = sysctl_handle_string(oidp, state, sizeof(state), req);
1175     if (error != 0 || req->newptr == NULL)
1176 	return (error);
1177     if (strlen(state) < 2 || toupper(state[0]) != 'C')
1178 	return (EINVAL);
1179     val = (int) strtol(state + 1, NULL, 10) - 1;
1180     if (val < 0 || val > cpu_cx_count - 1)
1181 	return (EINVAL);
1182     cpu_cx_lowest = val;
1183 
1184     /* Update the new lowest useable Cx state for all CPUs. */
1185     ACPI_SERIAL_BEGIN(cpu);
1186     for (i = 0; i < cpu_ndevices; i++) {
1187 	sc = device_get_softc(cpu_devices[i]);
1188 	acpi_cpu_set_cx_lowest(sc, val);
1189     }
1190     ACPI_SERIAL_END(cpu);
1191 
1192     return (0);
1193 }
1194