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/*
* arch/i386/kernel/acpi/cstate.c
*
* Copyright (C) 2005 Intel Corporation
* Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
* - Added _PDC for SMP C-states on Intel CPUs
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <acpi/processor.h>
#include <asm/acpi.h>
/*
* Initialize bm_flags based on the CPU cache properties
* On SMP it depends on cache configuration
* - When cache is not shared among all CPUs, we flush cache
* before entering C3.
* - When cache is shared among all CPUs, we use bm_check
* mechanism as in UP case
*
* This routine is called only after all the CPUs are online
*/
void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
unsigned int cpu)
{
struct cpuinfo_x86 *c = &cpu_data(cpu);
flags->bm_check = 0;
if (num_online_cpus() == 1)
flags->bm_check = 1;
else if (c->x86_vendor == X86_VENDOR_INTEL) {
/*
* Today all CPUs that support C3 share cache.
* TBD: This needs to look at cache shared map, once
* multi-core detection patch makes to the base.
*/
flags->bm_check = 1;
}
}
EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
/* The code below handles cstate entry with monitor-mwait pair on Intel*/
struct cstate_entry {
struct {
unsigned int eax;
unsigned int ecx;
} states[ACPI_PROCESSOR_MAX_POWER];
};
static struct cstate_entry *cpu_cstate_entry; /* per CPU ptr */
static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
#define MWAIT_SUBSTATE_MASK (0xf)
#define MWAIT_SUBSTATE_SIZE (4)
#define CPUID_MWAIT_LEAF (5)
#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
#define CPUID5_ECX_INTERRUPT_BREAK (0x2)
#define MWAIT_ECX_INTERRUPT_BREAK (0x1)
#define NATIVE_CSTATE_BEYOND_HALT (2)
int acpi_processor_ffh_cstate_probe(unsigned int cpu,
struct acpi_processor_cx *cx, struct acpi_power_register *reg)
{
struct cstate_entry *percpu_entry;
struct cpuinfo_x86 *c = &cpu_data(cpu);
cpumask_t saved_mask;
int retval;
unsigned int eax, ebx, ecx, edx;
unsigned int edx_part;
unsigned int cstate_type; /* C-state type and not ACPI C-state type */
unsigned int num_cstate_subtype;
if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF )
return -1;
if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
return -1;
percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
percpu_entry->states[cx->index].eax = 0;
percpu_entry->states[cx->index].ecx = 0;
/* Make sure we are running on right CPU */
saved_mask = current->cpus_allowed;
retval = set_cpus_allowed(current, cpumask_of_cpu(cpu));
if (retval)
return -1;
cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
/* Check whether this particular cx_type (in CST) is supported or not */
cstate_type = (cx->address >> MWAIT_SUBSTATE_SIZE) + 1;
edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
retval = 0;
if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
retval = -1;
goto out;
}
/* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
!(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
retval = -1;
goto out;
}
percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
/* Use the hint in CST */
percpu_entry->states[cx->index].eax = cx->address;
if (!mwait_supported[cstate_type]) {
mwait_supported[cstate_type] = 1;
printk(KERN_DEBUG "Monitor-Mwait will be used to enter C-%d "
"state\n", cx->type);
}
snprintf(cx->desc, ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",
cx->address);
out:
set_cpus_allowed(current, saved_mask);
return retval;
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
{
unsigned int cpu = smp_processor_id();
struct cstate_entry *percpu_entry;
percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
percpu_entry->states[cx->index].ecx);
}
EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
static int __init ffh_cstate_init(void)
{
struct cpuinfo_x86 *c = &boot_cpu_data;
if (c->x86_vendor != X86_VENDOR_INTEL)
return -1;
cpu_cstate_entry = alloc_percpu(struct cstate_entry);
return 0;
}
static void __exit ffh_cstate_exit(void)
{
free_percpu(cpu_cstate_entry);
cpu_cstate_entry = NULL;
}
arch_initcall(ffh_cstate_init);
__exitcall(ffh_cstate_exit);
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