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freebsd-dev/sys/dev/acpica/acpi_cpu.c
Andriy Gapon 30bf6110b5 acpi_cpu_notify: disable acpi_cpu_idle while updating C-state data 
... to avoid any races or inconsistencies.
This should fix a regression introduced in r243404.

Also, remove a stale comment that has not been true for quite a while
now.

Pointyhat to:	avg
Teested by:	trociny, emaste, dumbbell (earlier version)
MFC after:	 1 week
2012-12-01 18:06:05 +00:00

1322 lines
39 KiB
C
Raw Blame History

/*-
* Copyright (c) 2003-2005 Nate Lawson (SDG)
* Copyright (c) 2001 Michael Smith
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_acpi.h"
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/pcpu.h>
#include <sys/power.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/sbuf.h>
#include <sys/smp.h>
#include <dev/pci/pcivar.h>
#include <machine/atomic.h>
#include <machine/bus.h>
#if defined(__amd64__) || defined(__i386__)
#include <machine/clock.h>
#endif
#include <sys/rman.h>
#include <contrib/dev/acpica/include/acpi.h>
#include <contrib/dev/acpica/include/accommon.h>
#include <dev/acpica/acpivar.h>
/*
* Support for ACPI Processor devices, including C[1-3] sleep states.
*/
/* Hooks for the ACPI CA debugging infrastructure */
#define _COMPONENT ACPI_PROCESSOR
ACPI_MODULE_NAME("PROCESSOR")
struct acpi_cx {
struct resource *p_lvlx; /* Register to read to enter state. */
uint32_t type; /* C1-3 (C4 and up treated as C3). */
uint32_t trans_lat; /* Transition latency (usec). */
uint32_t power; /* Power consumed (mW). */
int res_type; /* Resource type for p_lvlx. */
int res_rid; /* Resource ID for p_lvlx. */
};
#define MAX_CX_STATES 8
struct acpi_cpu_softc {
device_t cpu_dev;
ACPI_HANDLE cpu_handle;
struct pcpu *cpu_pcpu;
uint32_t cpu_acpi_id; /* ACPI processor id */
uint32_t cpu_p_blk; /* ACPI P_BLK location */
uint32_t cpu_p_blk_len; /* P_BLK length (must be 6). */
struct acpi_cx cpu_cx_states[MAX_CX_STATES];
int cpu_cx_count; /* Number of valid Cx states. */
int cpu_prev_sleep;/* Last idle sleep duration. */
int cpu_features; /* Child driver supported features. */
/* Runtime state. */
int cpu_non_c3; /* Index of lowest non-C3 state. */
u_int cpu_cx_stats[MAX_CX_STATES];/* Cx usage history. */
/* Values for sysctl. */
struct sysctl_ctx_list cpu_sysctl_ctx;
struct sysctl_oid *cpu_sysctl_tree;
int cpu_cx_lowest;
int cpu_cx_lowest_lim;
int cpu_disable_idle; /* Disable entry to idle function */
char cpu_cx_supported[64];
};
struct acpi_cpu_device {
struct resource_list ad_rl;
};
#define CPU_GET_REG(reg, width) \
(bus_space_read_ ## width(rman_get_bustag((reg)), \
rman_get_bushandle((reg)), 0))
#define CPU_SET_REG(reg, width, val) \
(bus_space_write_ ## width(rman_get_bustag((reg)), \
rman_get_bushandle((reg)), 0, (val)))
#define PM_USEC(x) ((x) >> 2) /* ~4 clocks per usec (3.57955 Mhz) */
#define ACPI_NOTIFY_CX_STATES 0x81 /* _CST changed. */
#define CPU_QUIRK_NO_C3 (1<<0) /* C3-type states are not usable. */
#define CPU_QUIRK_NO_BM_CTRL (1<<2) /* No bus mastering control. */
#define PCI_VENDOR_INTEL 0x8086
#define PCI_DEVICE_82371AB_3 0x7113 /* PIIX4 chipset for quirks. */
#define PCI_REVISION_A_STEP 0
#define PCI_REVISION_B_STEP 1
#define PCI_REVISION_4E 2
#define PCI_REVISION_4M 3
#define PIIX4_DEVACTB_REG 0x58
#define PIIX4_BRLD_EN_IRQ0 (1<<0)
#define PIIX4_BRLD_EN_IRQ (1<<1)
#define PIIX4_BRLD_EN_IRQ8 (1<<5)
#define PIIX4_STOP_BREAK_MASK (PIIX4_BRLD_EN_IRQ0 | PIIX4_BRLD_EN_IRQ | PIIX4_BRLD_EN_IRQ8)
#define PIIX4_PCNTRL_BST_EN (1<<10)
/* Allow users to ignore processor orders in MADT. */
static int cpu_unordered;
TUNABLE_INT("debug.acpi.cpu_unordered", &cpu_unordered);
SYSCTL_INT(_debug_acpi, OID_AUTO, cpu_unordered, CTLFLAG_RDTUN,
&cpu_unordered, 0,
"Do not use the MADT to match ACPI Processor objects to CPUs.");
/* Platform hardware resource information. */
static uint32_t cpu_smi_cmd; /* Value to write to SMI_CMD. */
static uint8_t cpu_cst_cnt; /* Indicate we are _CST aware. */
static int cpu_quirks; /* Indicate any hardware bugs. */
/* Values for sysctl. */
static struct sysctl_ctx_list cpu_sysctl_ctx;
static struct sysctl_oid *cpu_sysctl_tree;
static int cpu_cx_generic;
static int cpu_cx_lowest_lim;
static device_t *cpu_devices;
static int cpu_ndevices;
static struct acpi_cpu_softc **cpu_softc;
ACPI_SERIAL_DECL(cpu, "ACPI CPU");
static int acpi_cpu_probe(device_t dev);
static int acpi_cpu_attach(device_t dev);
static int acpi_cpu_suspend(device_t dev);
static int acpi_cpu_resume(device_t dev);
static int acpi_pcpu_get_id(device_t dev, uint32_t *acpi_id,
uint32_t *cpu_id);
static struct resource_list *acpi_cpu_get_rlist(device_t dev, device_t child);
static device_t acpi_cpu_add_child(device_t dev, u_int order, const char *name,
int unit);
static int acpi_cpu_read_ivar(device_t dev, device_t child, int index,
uintptr_t *result);
static int acpi_cpu_shutdown(device_t dev);
static void acpi_cpu_cx_probe(struct acpi_cpu_softc *sc);
static void acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc);
static int acpi_cpu_cx_cst(struct acpi_cpu_softc *sc);
static void acpi_cpu_startup(void *arg);
static void acpi_cpu_startup_cx(struct acpi_cpu_softc *sc);
static void acpi_cpu_cx_list(struct acpi_cpu_softc *sc);
static void acpi_cpu_idle(void);
static void acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context);
static int acpi_cpu_quirks(void);
static int acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS);
static int acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc);
static int acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
static int acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS);
static device_method_t acpi_cpu_methods[] = {
/* Device interface */
DEVMETHOD(device_probe, acpi_cpu_probe),
DEVMETHOD(device_attach, acpi_cpu_attach),
DEVMETHOD(device_detach, bus_generic_detach),
DEVMETHOD(device_shutdown, acpi_cpu_shutdown),
DEVMETHOD(device_suspend, acpi_cpu_suspend),
DEVMETHOD(device_resume, acpi_cpu_resume),
/* Bus interface */
DEVMETHOD(bus_add_child, acpi_cpu_add_child),
DEVMETHOD(bus_read_ivar, acpi_cpu_read_ivar),
DEVMETHOD(bus_get_resource_list, acpi_cpu_get_rlist),
DEVMETHOD(bus_get_resource, bus_generic_rl_get_resource),
DEVMETHOD(bus_set_resource, bus_generic_rl_set_resource),
DEVMETHOD(bus_alloc_resource, bus_generic_rl_alloc_resource),
DEVMETHOD(bus_release_resource, bus_generic_rl_release_resource),
DEVMETHOD(bus_activate_resource, bus_generic_activate_resource),
DEVMETHOD(bus_deactivate_resource, bus_generic_deactivate_resource),
DEVMETHOD(bus_setup_intr, bus_generic_setup_intr),
DEVMETHOD(bus_teardown_intr, bus_generic_teardown_intr),
DEVMETHOD_END
};
static driver_t acpi_cpu_driver = {
"cpu",
acpi_cpu_methods,
sizeof(struct acpi_cpu_softc),
};
static devclass_t acpi_cpu_devclass;
DRIVER_MODULE(cpu, acpi, acpi_cpu_driver, acpi_cpu_devclass, 0, 0);
MODULE_DEPEND(cpu, acpi, 1, 1, 1);
static int
acpi_cpu_probe(device_t dev)
{
int acpi_id, cpu_id;
ACPI_BUFFER buf;
ACPI_HANDLE handle;
ACPI_OBJECT *obj;
ACPI_STATUS status;
if (acpi_disabled("cpu") || acpi_get_type(dev) != ACPI_TYPE_PROCESSOR)
return (ENXIO);
handle = acpi_get_handle(dev);
if (cpu_softc == NULL)
cpu_softc = malloc(sizeof(struct acpi_cpu_softc *) *
(mp_maxid + 1), M_TEMP /* XXX */, M_WAITOK | M_ZERO);
/* Get our Processor object. */
buf.Pointer = NULL;
buf.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(handle, NULL, NULL, &buf);
if (ACPI_FAILURE(status)) {
device_printf(dev, "probe failed to get Processor obj - %s\n",
AcpiFormatException(status));
return (ENXIO);
}
obj = (ACPI_OBJECT *)buf.Pointer;
if (obj->Type != ACPI_TYPE_PROCESSOR) {
device_printf(dev, "Processor object has bad type %d\n", obj->Type);
AcpiOsFree(obj);
return (ENXIO);
}
/*
* Find the processor associated with our unit. We could use the
* ProcId as a key, however, some boxes do not have the same values
* in their Processor object as the ProcId values in the MADT.
*/
acpi_id = obj->Processor.ProcId;
AcpiOsFree(obj);
if (acpi_pcpu_get_id(dev, &acpi_id, &cpu_id) != 0)
return (ENXIO);
/*
* Check if we already probed this processor. We scan the bus twice
* so it's possible we've already seen this one.
*/
if (cpu_softc[cpu_id] != NULL)
return (ENXIO);
/* Mark this processor as in-use and save our derived id for attach. */
cpu_softc[cpu_id] = (void *)1;
acpi_set_private(dev, (void*)(intptr_t)cpu_id);
device_set_desc(dev, "ACPI CPU");
return (0);
}
static int
acpi_cpu_attach(device_t dev)
{
ACPI_BUFFER buf;
ACPI_OBJECT arg[4], *obj;
ACPI_OBJECT_LIST arglist;
struct pcpu *pcpu_data;
struct acpi_cpu_softc *sc;
struct acpi_softc *acpi_sc;
ACPI_STATUS status;
u_int features;
int cpu_id, drv_count, i;
driver_t **drivers;
uint32_t cap_set[3];
/* UUID needed by _OSC evaluation */
static uint8_t cpu_oscuuid[16] = { 0x16, 0xA6, 0x77, 0x40, 0x0C, 0x29,
0xBE, 0x47, 0x9E, 0xBD, 0xD8, 0x70,
0x58, 0x71, 0x39, 0x53 };
ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
sc = device_get_softc(dev);
sc->cpu_dev = dev;
sc->cpu_handle = acpi_get_handle(dev);
cpu_id = (int)(intptr_t)acpi_get_private(dev);
cpu_softc[cpu_id] = sc;
pcpu_data = pcpu_find(cpu_id);
pcpu_data->pc_device = dev;
sc->cpu_pcpu = pcpu_data;
cpu_smi_cmd = AcpiGbl_FADT.SmiCommand;
cpu_cst_cnt = AcpiGbl_FADT.CstControl;
buf.Pointer = NULL;
buf.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(sc->cpu_handle, NULL, NULL, &buf);
if (ACPI_FAILURE(status)) {
device_printf(dev, "attach failed to get Processor obj - %s\n",
AcpiFormatException(status));
return (ENXIO);
}
obj = (ACPI_OBJECT *)buf.Pointer;
sc->cpu_p_blk = obj->Processor.PblkAddress;
sc->cpu_p_blk_len = obj->Processor.PblkLength;
sc->cpu_acpi_id = obj->Processor.ProcId;
AcpiOsFree(obj);
ACPI_DEBUG_PRINT((ACPI_DB_INFO, "acpi_cpu%d: P_BLK at %#x/%d\n",
device_get_unit(dev), sc->cpu_p_blk, sc->cpu_p_blk_len));
/*
* If this is the first cpu we attach, create and initialize the generic
* resources that will be used by all acpi cpu devices.
*/
if (device_get_unit(dev) == 0) {
/* Assume we won't be using generic Cx mode by default */
cpu_cx_generic = FALSE;
/* Install hw.acpi.cpu sysctl tree */
acpi_sc = acpi_device_get_parent_softc(dev);
sysctl_ctx_init(&cpu_sysctl_ctx);
cpu_sysctl_tree = SYSCTL_ADD_NODE(&cpu_sysctl_ctx,
SYSCTL_CHILDREN(acpi_sc->acpi_sysctl_tree), OID_AUTO, "cpu",
CTLFLAG_RD, 0, "node for CPU children");
/* Queue post cpu-probing task handler */
AcpiOsExecute(OSL_NOTIFY_HANDLER, acpi_cpu_startup, NULL);
}
/*
* Before calling any CPU methods, collect child driver feature hints
* and notify ACPI of them. We support unified SMP power control
* so advertise this ourselves. Note this is not the same as independent
* SMP control where each CPU can have different settings.
*/
sc->cpu_features = ACPI_CAP_SMP_SAME | ACPI_CAP_SMP_SAME_C3;
if (devclass_get_drivers(acpi_cpu_devclass, &drivers, &drv_count) == 0) {
for (i = 0; i < drv_count; i++) {
if (ACPI_GET_FEATURES(drivers[i], &features) == 0)
sc->cpu_features |= features;
}
free(drivers, M_TEMP);
}
/*
* CPU capabilities are specified in
* Intel Processor Vendor-Specific ACPI Interface Specification.
*/
if (sc->cpu_features) {
arglist.Pointer = arg;
arglist.Count = 4;
arg[0].Type = ACPI_TYPE_BUFFER;
arg[0].Buffer.Length = sizeof(cpu_oscuuid);
arg[0].Buffer.Pointer = cpu_oscuuid; /* UUID */
arg[1].Type = ACPI_TYPE_INTEGER;
arg[1].Integer.Value = 1; /* revision */
arg[2].Type = ACPI_TYPE_INTEGER;
arg[2].Integer.Value = 1; /* count */
arg[3].Type = ACPI_TYPE_BUFFER;
arg[3].Buffer.Length = sizeof(cap_set); /* Capabilities buffer */
arg[3].Buffer.Pointer = (uint8_t *)cap_set;
cap_set[0] = 0; /* status */
cap_set[1] = sc->cpu_features;
status = AcpiEvaluateObject(sc->cpu_handle, "_OSC", &arglist, NULL);
if (ACPI_SUCCESS(status)) {
if (cap_set[0] != 0)
device_printf(dev, "_OSC returned status %#x\n", cap_set[0]);
}
else {
arglist.Pointer = arg;
arglist.Count = 1;
arg[0].Type = ACPI_TYPE_BUFFER;
arg[0].Buffer.Length = sizeof(cap_set);
arg[0].Buffer.Pointer = (uint8_t *)cap_set;
cap_set[0] = 1; /* revision */
cap_set[1] = 1; /* number of capabilities integers */
cap_set[2] = sc->cpu_features;
AcpiEvaluateObject(sc->cpu_handle, "_PDC", &arglist, NULL);
}
}
/* Probe for Cx state support. */
acpi_cpu_cx_probe(sc);
return (0);
}
static void
acpi_cpu_postattach(void *unused __unused)
{
device_t *devices;
int err;
int i, n;
err = devclass_get_devices(acpi_cpu_devclass, &devices, &n);
if (err != 0) {
printf("devclass_get_devices(acpi_cpu_devclass) failed\n");
return;
}
for (i = 0; i < n; i++)
bus_generic_probe(devices[i]);
for (i = 0; i < n; i++)
bus_generic_attach(devices[i]);
free(devices, M_TEMP);
}
SYSINIT(acpi_cpu, SI_SUB_CONFIGURE, SI_ORDER_MIDDLE,
acpi_cpu_postattach, NULL);
static void
disable_idle(struct acpi_cpu_softc *sc)
{
cpuset_t cpuset;
CPU_SETOF(sc->cpu_pcpu->pc_cpuid, &cpuset);
sc->cpu_disable_idle = TRUE;
/*
* Ensure that the CPU is not in idle state or in acpi_cpu_idle().
* Note that this code depends on the fact that the rendezvous IPI
* can not penetrate context where interrupts are disabled and acpi_cpu_idle
* is called and executed in such a context with interrupts being re-enabled
* right before return.
*/
smp_rendezvous_cpus(cpuset, smp_no_rendevous_barrier, NULL,
smp_no_rendevous_barrier, NULL);
}
static void
enable_idle(struct acpi_cpu_softc *sc)
{
sc->cpu_disable_idle = FALSE;
}
static int
is_idle_disabled(struct acpi_cpu_softc *sc)
{
return (sc->cpu_disable_idle);
}
/*
* Disable any entry to the idle function during suspend and re-enable it
* during resume.
*/
static int
acpi_cpu_suspend(device_t dev)
{
int error;
error = bus_generic_suspend(dev);
if (error)
return (error);
disable_idle(device_get_softc(dev));
return (0);
}
static int
acpi_cpu_resume(device_t dev)
{
enable_idle(device_get_softc(dev));
return (bus_generic_resume(dev));
}
/*
* Find the processor associated with a given ACPI ID. By default,
* use the MADT to map ACPI IDs to APIC IDs and use that to locate a
* processor. Some systems have inconsistent ASL and MADT however.
* For these systems the cpu_unordered tunable can be set in which
* case we assume that Processor objects are listed in the same order
* in both the MADT and ASL.
*/
static int
acpi_pcpu_get_id(device_t dev, uint32_t *acpi_id, uint32_t *cpu_id)
{
struct pcpu *pc;
uint32_t i, idx;
KASSERT(acpi_id != NULL, ("Null acpi_id"));
KASSERT(cpu_id != NULL, ("Null cpu_id"));
idx = device_get_unit(dev);
/*
* If pc_acpi_id for CPU 0 is not initialized (e.g. a non-APIC
* UP box) use the ACPI ID from the first processor we find.
*/
if (idx == 0 && mp_ncpus == 1) {
pc = pcpu_find(0);
if (pc->pc_acpi_id == 0xffffffff)
pc->pc_acpi_id = *acpi_id;
*cpu_id = 0;
return (0);
}
CPU_FOREACH(i) {
pc = pcpu_find(i);
KASSERT(pc != NULL, ("no pcpu data for %d", i));
if (cpu_unordered) {
if (idx-- == 0) {
/*
* If pc_acpi_id doesn't match the ACPI ID from the
* ASL, prefer the MADT-derived value.
*/
if (pc->pc_acpi_id != *acpi_id)
*acpi_id = pc->pc_acpi_id;
*cpu_id = pc->pc_cpuid;
return (0);
}
} else {
if (pc->pc_acpi_id == *acpi_id) {
if (bootverbose)
device_printf(dev,
"Processor %s (ACPI ID %u) -> APIC ID %d\n",
acpi_name(acpi_get_handle(dev)), *acpi_id,
pc->pc_cpuid);
*cpu_id = pc->pc_cpuid;
return (0);
}
}
}
if (bootverbose)
printf("ACPI: Processor %s (ACPI ID %u) ignored\n",
acpi_name(acpi_get_handle(dev)), *acpi_id);
return (ESRCH);
}
static struct resource_list *
acpi_cpu_get_rlist(device_t dev, device_t child)
{
struct acpi_cpu_device *ad;
ad = device_get_ivars(child);
if (ad == NULL)
return (NULL);
return (&ad->ad_rl);
}
static device_t
acpi_cpu_add_child(device_t dev, u_int order, const char *name, int unit)
{
struct acpi_cpu_device *ad;
device_t child;
if ((ad = malloc(sizeof(*ad), M_TEMP, M_NOWAIT | M_ZERO)) == NULL)
return (NULL);
resource_list_init(&ad->ad_rl);
child = device_add_child_ordered(dev, order, name, unit);
if (child != NULL)
device_set_ivars(child, ad);
else
free(ad, M_TEMP);
return (child);
}
static int
acpi_cpu_read_ivar(device_t dev, device_t child, int index, uintptr_t *result)
{
struct acpi_cpu_softc *sc;
sc = device_get_softc(dev);
switch (index) {
case ACPI_IVAR_HANDLE:
*result = (uintptr_t)sc->cpu_handle;
break;
case CPU_IVAR_PCPU:
*result = (uintptr_t)sc->cpu_pcpu;
break;
#if defined(__amd64__) || defined(__i386__)
case CPU_IVAR_NOMINAL_MHZ:
if (tsc_is_invariant) {
*result = (uintptr_t)(atomic_load_acq_64(&tsc_freq) / 1000000);
break;
}
/* FALLTHROUGH */
#endif
default:
return (ENOENT);
}
return (0);
}
static int
acpi_cpu_shutdown(device_t dev)
{
ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
/* Allow children to shutdown first. */
bus_generic_shutdown(dev);
/*
* Disable any entry to the idle function.
*/
disable_idle(device_get_softc(dev));
/*
* CPU devices are not truely detached and remain referenced,
* so their resources are not freed.
*/
return_VALUE (0);
}
static void
acpi_cpu_cx_probe(struct acpi_cpu_softc *sc)
{
ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
/* Use initial sleep value of 1 sec. to start with lowest idle state. */
sc->cpu_prev_sleep = 1000000;
sc->cpu_cx_lowest = 0;
sc->cpu_cx_lowest_lim = 0;
/*
* Check for the ACPI 2.0 _CST sleep states object. If we can't find
* any, we'll revert to generic FADT/P_BLK Cx control method which will
* be handled by acpi_cpu_startup. We need to defer to after having
* probed all the cpus in the system before probing for generic Cx
* states as we may already have found cpus with valid _CST packages
*/
if (!cpu_cx_generic && acpi_cpu_cx_cst(sc) != 0) {
/*
* We were unable to find a _CST package for this cpu or there
* was an error parsing it. Switch back to generic mode.
*/
cpu_cx_generic = TRUE;
if (bootverbose)
device_printf(sc->cpu_dev, "switching to generic Cx mode\n");
}
/*
* TODO: _CSD Package should be checked here.
*/
}
static void
acpi_cpu_generic_cx_probe(struct acpi_cpu_softc *sc)
{
ACPI_GENERIC_ADDRESS gas;
struct acpi_cx *cx_ptr;
sc->cpu_cx_count = 0;
cx_ptr = sc->cpu_cx_states;
/* Use initial sleep value of 1 sec. to start with lowest idle state. */
sc->cpu_prev_sleep = 1000000;
/* C1 has been required since just after ACPI 1.0 */
cx_ptr->type = ACPI_STATE_C1;
cx_ptr->trans_lat = 0;
cx_ptr++;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
/*
* The spec says P_BLK must be 6 bytes long. However, some systems
* use it to indicate a fractional set of features present so we
* take 5 as C2. Some may also have a value of 7 to indicate
* another C3 but most use _CST for this (as required) and having
* "only" C1-C3 is not a hardship.
*/
if (sc->cpu_p_blk_len < 5)
return;
/* Validate and allocate resources for C2 (P_LVL2). */
gas.SpaceId = ACPI_ADR_SPACE_SYSTEM_IO;
gas.BitWidth = 8;
if (AcpiGbl_FADT.C2Latency <= 100) {
gas.Address = sc->cpu_p_blk + 4;
cx_ptr->res_rid = 0;
acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &cx_ptr->res_rid,
&gas, &cx_ptr->p_lvlx, RF_SHAREABLE);
if (cx_ptr->p_lvlx != NULL) {
cx_ptr->type = ACPI_STATE_C2;
cx_ptr->trans_lat = AcpiGbl_FADT.C2Latency;
cx_ptr++;
sc->cpu_non_c3 = sc->cpu_cx_count;
sc->cpu_cx_count++;
}
}
if (sc->cpu_p_blk_len < 6)
return;
/* Validate and allocate resources for C3 (P_LVL3). */
if (AcpiGbl_FADT.C3Latency <= 1000 && !(cpu_quirks & CPU_QUIRK_NO_C3)) {
gas.Address = sc->cpu_p_blk + 5;
cx_ptr->res_rid = 1;
acpi_bus_alloc_gas(sc->cpu_dev, &cx_ptr->res_type, &cx_ptr->res_rid,
&gas, &cx_ptr->p_lvlx, RF_SHAREABLE);
if (cx_ptr->p_lvlx != NULL) {
cx_ptr->type = ACPI_STATE_C3;
cx_ptr->trans_lat = AcpiGbl_FADT.C3Latency;
cx_ptr++;
sc->cpu_cx_count++;
cpu_can_deep_sleep = 1;
}
}
}
/*
* Parse a _CST package and set up its Cx states. Since the _CST object
* can change dynamically, our notify handler may call this function
* to clean up and probe the new _CST package.
*/
static int
acpi_cpu_cx_cst(struct acpi_cpu_softc *sc)
{
struct acpi_cx *cx_ptr;
ACPI_STATUS status;
ACPI_BUFFER buf;
ACPI_OBJECT *top;
ACPI_OBJECT *pkg;
uint32_t count;
int i;
ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
buf.Pointer = NULL;
buf.Length = ACPI_ALLOCATE_BUFFER;
status = AcpiEvaluateObject(sc->cpu_handle, "_CST", NULL, &buf);
if (ACPI_FAILURE(status))
return (ENXIO);
/* _CST is a package with a count and at least one Cx package. */
top = (ACPI_OBJECT *)buf.Pointer;
if (!ACPI_PKG_VALID(top, 2) || acpi_PkgInt32(top, 0, &count) != 0) {
device_printf(sc->cpu_dev, "invalid _CST package\n");
AcpiOsFree(buf.Pointer);
return (ENXIO);
}
if (count != top->Package.Count - 1) {
device_printf(sc->cpu_dev, "invalid _CST state count (%d != %d)\n",
count, top->Package.Count - 1);
count = top->Package.Count - 1;
}
if (count > MAX_CX_STATES) {
device_printf(sc->cpu_dev, "_CST has too many states (%d)\n", count);
count = MAX_CX_STATES;
}
sc->cpu_non_c3 = 0;
sc->cpu_cx_count = 0;
cx_ptr = sc->cpu_cx_states;
/*
* C1 has been required since just after ACPI 1.0.
* Reserve the first slot for it.
*/
cx_ptr->type = ACPI_STATE_C0;
cx_ptr++;
sc->cpu_cx_count++;
/* Set up all valid states. */
for (i = 0; i < count; i++) {
pkg = &top->Package.Elements[i + 1];
if (!ACPI_PKG_VALID(pkg, 4) ||
acpi_PkgInt32(pkg, 1, &cx_ptr->type) != 0 ||
acpi_PkgInt32(pkg, 2, &cx_ptr->trans_lat) != 0 ||
acpi_PkgInt32(pkg, 3, &cx_ptr->power) != 0) {
device_printf(sc->cpu_dev, "skipping invalid Cx state package\n");
continue;
}
/* Validate the state to see if we should use it. */
switch (cx_ptr->type) {
case ACPI_STATE_C1:
if (sc->cpu_cx_states[0].type == ACPI_STATE_C0) {
/* This is the first C1 state. Use the reserved slot. */
sc->cpu_cx_states[0] = *cx_ptr;
} else {
sc->cpu_non_c3 = sc->cpu_cx_count;
cx_ptr++;
sc->cpu_cx_count++;
}
continue;
case ACPI_STATE_C2:
sc->cpu_non_c3 = sc->cpu_cx_count;
break;
case ACPI_STATE_C3:
default:
if ((cpu_quirks & CPU_QUIRK_NO_C3) != 0) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu%d: C3[%d] not available.\n",
device_get_unit(sc->cpu_dev), i));
continue;
} else
cpu_can_deep_sleep = 1;
break;
}
/* Free up any previous register. */
if (cx_ptr->p_lvlx != NULL) {
bus_release_resource(sc->cpu_dev, cx_ptr->res_type, cx_ptr->res_rid,
cx_ptr->p_lvlx);
cx_ptr->p_lvlx = NULL;
}
/* Allocate the control register for C2 or C3. */
cx_ptr->res_rid = sc->cpu_cx_count;
acpi_PkgGas(sc->cpu_dev, pkg, 0, &cx_ptr->res_type, &cx_ptr->res_rid,
&cx_ptr->p_lvlx, RF_SHAREABLE);
if (cx_ptr->p_lvlx) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu%d: Got C%d - %d latency\n",
device_get_unit(sc->cpu_dev), cx_ptr->type,
cx_ptr->trans_lat));
cx_ptr++;
sc->cpu_cx_count++;
}
}
AcpiOsFree(buf.Pointer);
/* If C1 state was not found, we need one now. */
cx_ptr = sc->cpu_cx_states;
if (cx_ptr->type == ACPI_STATE_C0) {
cx_ptr->type = ACPI_STATE_C1;
cx_ptr->trans_lat = 0;
}
return (0);
}
/*
* Call this *after* all CPUs have been attached.
*/
static void
acpi_cpu_startup(void *arg)
{
struct acpi_cpu_softc *sc;
int i;
/* Get set of CPU devices */
devclass_get_devices(acpi_cpu_devclass, &cpu_devices, &cpu_ndevices);
/*
* Setup any quirks that might necessary now that we have probed
* all the CPUs
*/
acpi_cpu_quirks();
if (cpu_cx_generic) {
/*
* We are using generic Cx mode, probe for available Cx states
* for all processors.
*/
for (i = 0; i < cpu_ndevices; i++) {
sc = device_get_softc(cpu_devices[i]);
acpi_cpu_generic_cx_probe(sc);
}
} else {
/*
* We are using _CST mode, remove C3 state if necessary.
* As we now know for sure that we will be using _CST mode
* install our notify handler.
*/
for (i = 0; i < cpu_ndevices; i++) {
sc = device_get_softc(cpu_devices[i]);
if (cpu_quirks & CPU_QUIRK_NO_C3) {
sc->cpu_cx_count = sc->cpu_non_c3 + 1;
}
AcpiInstallNotifyHandler(sc->cpu_handle, ACPI_DEVICE_NOTIFY,
acpi_cpu_notify, sc);
}
}
/* Perform Cx final initialization. */
for (i = 0; i < cpu_ndevices; i++) {
sc = device_get_softc(cpu_devices[i]);
acpi_cpu_startup_cx(sc);
}
/* Add a sysctl handler to handle global Cx lowest setting */
SYSCTL_ADD_PROC(&cpu_sysctl_ctx, SYSCTL_CHILDREN(cpu_sysctl_tree),
OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
NULL, 0, acpi_cpu_global_cx_lowest_sysctl, "A",
"Global lowest Cx sleep state to use");
/* Take over idling from cpu_idle_default(). */
cpu_cx_lowest_lim = 0;
for (i = 0; i < cpu_ndevices; i++) {
sc = device_get_softc(cpu_devices[i]);
enable_idle(sc);
}
cpu_idle_hook = acpi_cpu_idle;
}
static void
acpi_cpu_cx_list(struct acpi_cpu_softc *sc)
{
struct sbuf sb;
int i;
/*
* Set up the list of Cx states
*/
sbuf_new(&sb, sc->cpu_cx_supported, sizeof(sc->cpu_cx_supported),
SBUF_FIXEDLEN);
for (i = 0; i < sc->cpu_cx_count; i++)
sbuf_printf(&sb, "C%d/%d/%d ", i + 1, sc->cpu_cx_states[i].type,
sc->cpu_cx_states[i].trans_lat);
sbuf_trim(&sb);
sbuf_finish(&sb);
}
static void
acpi_cpu_startup_cx(struct acpi_cpu_softc *sc)
{
acpi_cpu_cx_list(sc);
SYSCTL_ADD_STRING(&sc->cpu_sysctl_ctx,
SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
OID_AUTO, "cx_supported", CTLFLAG_RD,
sc->cpu_cx_supported, 0,
"Cx/microsecond values for supported Cx states");
SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
OID_AUTO, "cx_lowest", CTLTYPE_STRING | CTLFLAG_RW,
(void *)sc, 0, acpi_cpu_cx_lowest_sysctl, "A",
"lowest Cx sleep state to use");
SYSCTL_ADD_PROC(&sc->cpu_sysctl_ctx,
SYSCTL_CHILDREN(device_get_sysctl_tree(sc->cpu_dev)),
OID_AUTO, "cx_usage", CTLTYPE_STRING | CTLFLAG_RD,
(void *)sc, 0, acpi_cpu_usage_sysctl, "A",
"percent usage for each Cx state");
/* Signal platform that we can handle _CST notification. */
if (!cpu_cx_generic && cpu_cst_cnt != 0) {
ACPI_LOCK(acpi);
AcpiOsWritePort(cpu_smi_cmd, cpu_cst_cnt, 8);
ACPI_UNLOCK(acpi);
}
}
/*
* Idle the CPU in the lowest state possible. This function is called with
* interrupts disabled. Note that once it re-enables interrupts, a task
* switch can occur so do not access shared data (i.e. the softc) after
* interrupts are re-enabled.
*/
static void
acpi_cpu_idle()
{
struct acpi_cpu_softc *sc;
struct acpi_cx *cx_next;
uint64_t cputicks;
uint32_t start_time, end_time;
int bm_active, cx_next_idx, i;
/*
* Look up our CPU id to get our softc. If it's NULL, we'll use C1
* since there is no ACPI processor object for this CPU. This occurs
* for logical CPUs in the HTT case.
*/
sc = cpu_softc[PCPU_GET(cpuid)];
if (sc == NULL) {
acpi_cpu_c1();
return;
}
/* If disabled, take the safe path. */
if (is_idle_disabled(sc)) {
acpi_cpu_c1();
return;
}
/* Find the lowest state that has small enough latency. */
cx_next_idx = 0;
if (cpu_disable_deep_sleep)
i = min(sc->cpu_cx_lowest, sc->cpu_non_c3);
else
i = sc->cpu_cx_lowest;
for (; i >= 0; i--) {
if (sc->cpu_cx_states[i].trans_lat * 3 <= sc->cpu_prev_sleep) {
cx_next_idx = i;
break;
}
}
/*
* Check for bus master activity. If there was activity, clear
* the bit and use the lowest non-C3 state. Note that the USB
* driver polling for new devices keeps this bit set all the
* time if USB is loaded.
*/
if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0 &&
cx_next_idx > sc->cpu_non_c3) {
AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, &bm_active);
if (bm_active != 0) {
AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_STATUS, 1);
cx_next_idx = sc->cpu_non_c3;
}
}
/* Select the next state and update statistics. */
cx_next = &sc->cpu_cx_states[cx_next_idx];
sc->cpu_cx_stats[cx_next_idx]++;
KASSERT(cx_next->type != ACPI_STATE_C0, ("acpi_cpu_idle: C0 sleep"));
/*
* Execute HLT (or equivalent) and wait for an interrupt. We can't
* precisely calculate the time spent in C1 since the place we wake up
* is an ISR. Assume we slept no more then half of quantum, unless
* we are called inside critical section, delaying context switch.
*/
if (cx_next->type == ACPI_STATE_C1) {
cputicks = cpu_ticks();
acpi_cpu_c1();
end_time = ((cpu_ticks() - cputicks) << 20) / cpu_tickrate();
if (curthread->td_critnest == 0)
end_time = min(end_time, 500000 / hz);
sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + end_time) / 4;
return;
}
/*
* For C3, disable bus master arbitration and enable bus master wake
* if BM control is available, otherwise flush the CPU cache.
*/
if (cx_next->type == ACPI_STATE_C3) {
if ((cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 1);
AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 1);
} else
ACPI_FLUSH_CPU_CACHE();
}
/*
* Read from P_LVLx to enter C2(+), checking time spent asleep.
* Use the ACPI timer for measuring sleep time. Since we need to
* get the time very close to the CPU start/stop clock logic, this
* is the only reliable time source.
*/
if (cx_next->type == ACPI_STATE_C3) {
AcpiHwRead(&start_time, &AcpiGbl_FADT.XPmTimerBlock);
cputicks = 0;
} else {
start_time = 0;
cputicks = cpu_ticks();
}
CPU_GET_REG(cx_next->p_lvlx, 1);
/*
* Read the end time twice. Since it may take an arbitrary time
* to enter the idle state, the first read may be executed before
* the processor has stopped. Doing it again provides enough
* margin that we are certain to have a correct value.
*/
AcpiHwRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
if (cx_next->type == ACPI_STATE_C3) {
AcpiHwRead(&end_time, &AcpiGbl_FADT.XPmTimerBlock);
end_time = acpi_TimerDelta(end_time, start_time);
} else
end_time = ((cpu_ticks() - cputicks) << 20) / cpu_tickrate();
/* Enable bus master arbitration and disable bus master wakeup. */
if (cx_next->type == ACPI_STATE_C3 &&
(cpu_quirks & CPU_QUIRK_NO_BM_CTRL) == 0) {
AcpiWriteBitRegister(ACPI_BITREG_ARB_DISABLE, 0);
AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
}
ACPI_ENABLE_IRQS();
sc->cpu_prev_sleep = (sc->cpu_prev_sleep * 3 + PM_USEC(end_time)) / 4;
}
/*
* Re-evaluate the _CST object when we are notified that it changed.
*/
static void
acpi_cpu_notify(ACPI_HANDLE h, UINT32 notify, void *context)
{
struct acpi_cpu_softc *sc = (struct acpi_cpu_softc *)context;
if (notify != ACPI_NOTIFY_CX_STATES)
return;
/*
* C-state data for target CPU is going to be in flux while we execute
* acpi_cpu_cx_cst, so disable entering acpi_cpu_idle.
* Also, it may happen that multiple ACPI taskqueues may concurrently
* execute notifications for the same CPU. ACPI_SERIAL is used to
* protect against that.
*/
ACPI_SERIAL_BEGIN(cpu);
disable_idle(sc);
/* Update the list of Cx states. */
acpi_cpu_cx_cst(sc);
acpi_cpu_cx_list(sc);
acpi_cpu_set_cx_lowest(sc);
enable_idle(sc);
ACPI_SERIAL_END(cpu);
acpi_UserNotify("PROCESSOR", sc->cpu_handle, notify);
}
static int
acpi_cpu_quirks(void)
{
device_t acpi_dev;
uint32_t val;
ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
/*
* Bus mastering arbitration control is needed to keep caches coherent
* while sleeping in C3. If it's not present but a working flush cache
* instruction is present, flush the caches before entering C3 instead.
* Otherwise, just disable C3 completely.
*/
if (AcpiGbl_FADT.Pm2ControlBlock == 0 ||
AcpiGbl_FADT.Pm2ControlLength == 0) {
if ((AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD) &&
(AcpiGbl_FADT.Flags & ACPI_FADT_WBINVD_FLUSH) == 0) {
cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: no BM control, using flush cache method\n"));
} else {
cpu_quirks |= CPU_QUIRK_NO_C3;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: no BM control, C3 not available\n"));
}
}
/*
* If we are using generic Cx mode, C3 on multiple CPUs requires using
* the expensive flush cache instruction.
*/
if (cpu_cx_generic && mp_ncpus > 1) {
cpu_quirks |= CPU_QUIRK_NO_BM_CTRL;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: SMP, using flush cache mode for C3\n"));
}
/* Look for various quirks of the PIIX4 part. */
acpi_dev = pci_find_device(PCI_VENDOR_INTEL, PCI_DEVICE_82371AB_3);
if (acpi_dev != NULL) {
switch (pci_get_revid(acpi_dev)) {
/*
* Disable C3 support for all PIIX4 chipsets. Some of these parts
* do not report the BMIDE status to the BM status register and
* others have a livelock bug if Type-F DMA is enabled. Linux
* works around the BMIDE bug by reading the BM status directly
* but we take the simpler approach of disabling C3 for these
* parts.
*
* See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
* Livelock") from the January 2002 PIIX4 specification update.
* Applies to all PIIX4 models.
*
* Also, make sure that all interrupts cause a "Stop Break"
* event to exit from C2 state.
* Also, BRLD_EN_BM (ACPI_BITREG_BUS_MASTER_RLD in ACPI-speak)
* should be set to zero, otherwise it causes C2 to short-sleep.
* PIIX4 doesn't properly support C3 and bus master activity
* need not break out of C2.
*/
case PCI_REVISION_A_STEP:
case PCI_REVISION_B_STEP:
case PCI_REVISION_4E:
case PCI_REVISION_4M:
cpu_quirks |= CPU_QUIRK_NO_C3;
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: working around PIIX4 bug, disabling C3\n"));
val = pci_read_config(acpi_dev, PIIX4_DEVACTB_REG, 4);
if ((val & PIIX4_STOP_BREAK_MASK) != PIIX4_STOP_BREAK_MASK) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: PIIX4: enabling IRQs to generate Stop Break\n"));
val |= PIIX4_STOP_BREAK_MASK;
pci_write_config(acpi_dev, PIIX4_DEVACTB_REG, val, 4);
}
AcpiReadBitRegister(ACPI_BITREG_BUS_MASTER_RLD, &val);
if (val) {
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"acpi_cpu: PIIX4: reset BRLD_EN_BM\n"));
AcpiWriteBitRegister(ACPI_BITREG_BUS_MASTER_RLD, 0);
}
break;
default:
break;
}
}
return (0);
}
static int
acpi_cpu_usage_sysctl(SYSCTL_HANDLER_ARGS)
{
struct acpi_cpu_softc *sc;
struct sbuf sb;
char buf[128];
int i;
uintmax_t fract, sum, whole;
sc = (struct acpi_cpu_softc *) arg1;
sum = 0;
for (i = 0; i < sc->cpu_cx_count; i++)
sum += sc->cpu_cx_stats[i];
sbuf_new(&sb, buf, sizeof(buf), SBUF_FIXEDLEN);
for (i = 0; i < sc->cpu_cx_count; i++) {
if (sum > 0) {
whole = (uintmax_t)sc->cpu_cx_stats[i] * 100;
fract = (whole % sum) * 100;
sbuf_printf(&sb, "%u.%02u%% ", (u_int)(whole / sum),
(u_int)(fract / sum));
} else
sbuf_printf(&sb, "0.00%% ");
}
sbuf_printf(&sb, "last %dus", sc->cpu_prev_sleep);
sbuf_trim(&sb);
sbuf_finish(&sb);
sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
sbuf_delete(&sb);
return (0);
}
static int
acpi_cpu_set_cx_lowest(struct acpi_cpu_softc *sc)
{
int i;
ACPI_SERIAL_ASSERT(cpu);
sc->cpu_cx_lowest = min(sc->cpu_cx_lowest_lim, sc->cpu_cx_count - 1);
/* If not disabling, cache the new lowest non-C3 state. */
sc->cpu_non_c3 = 0;
for (i = sc->cpu_cx_lowest; i >= 0; i--) {
if (sc->cpu_cx_states[i].type < ACPI_STATE_C3) {
sc->cpu_non_c3 = i;
break;
}
}
/* Reset the statistics counters. */
bzero(sc->cpu_cx_stats, sizeof(sc->cpu_cx_stats));
return (0);
}
static int
acpi_cpu_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
{
struct acpi_cpu_softc *sc;
char state[8];
int val, error;
sc = (struct acpi_cpu_softc *) arg1;
snprintf(state, sizeof(state), "C%d", sc->cpu_cx_lowest_lim + 1);
error = sysctl_handle_string(oidp, state, sizeof(state), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (strlen(state) < 2 || toupper(state[0]) != 'C')
return (EINVAL);
if (strcasecmp(state, "Cmax") == 0)
val = MAX_CX_STATES;
else {
val = (int) strtol(state + 1, NULL, 10);
if (val < 1 || val > MAX_CX_STATES)
return (EINVAL);
}
ACPI_SERIAL_BEGIN(cpu);
sc->cpu_cx_lowest_lim = val - 1;
acpi_cpu_set_cx_lowest(sc);
ACPI_SERIAL_END(cpu);
return (0);
}
static int
acpi_cpu_global_cx_lowest_sysctl(SYSCTL_HANDLER_ARGS)
{
struct acpi_cpu_softc *sc;
char state[8];
int val, error, i;
snprintf(state, sizeof(state), "C%d", cpu_cx_lowest_lim + 1);
error = sysctl_handle_string(oidp, state, sizeof(state), req);
if (error != 0 || req->newptr == NULL)
return (error);
if (strlen(state) < 2 || toupper(state[0]) != 'C')
return (EINVAL);
if (strcasecmp(state, "Cmax") == 0)
val = MAX_CX_STATES;
else {
val = (int) strtol(state + 1, NULL, 10);
if (val < 1 || val > MAX_CX_STATES)
return (EINVAL);
}
/* Update the new lowest useable Cx state for all CPUs. */
ACPI_SERIAL_BEGIN(cpu);
cpu_cx_lowest_lim = val - 1;
for (i = 0; i < cpu_ndevices; i++) {
sc = device_get_softc(cpu_devices[i]);
sc->cpu_cx_lowest_lim = cpu_cx_lowest_lim;
acpi_cpu_set_cx_lowest(sc);
}
ACPI_SERIAL_END(cpu);
return (0);
}
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