linux/drivers/acpi/processor_pdc.c
Alex Chiang 1d9cb470a7 ACPI: processor: introduce arch_has_acpi_pdc
arch dependent helper function that tells us if we should attempt to
evaluate _PDC on this machine or not.

The x86 implementation assumes that the CPUs in the machine must be
homogeneous, and that you cannot mix CPUs of different vendors.

Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>
2009-12-22 03:24:10 -05:00

112 lines
2.7 KiB
C

#include <linux/dmi.h>
#include <acpi/acpi_drivers.h>
#include <acpi/processor.h>
#include "internal.h"
#define PREFIX "ACPI: "
#define _COMPONENT ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("processor_pdc");
static int set_no_mwait(const struct dmi_system_id *id)
{
printk(KERN_NOTICE PREFIX "%s detected - "
"disabling mwait for CPU C-states\n", id->ident);
idle_nomwait = 1;
return 0;
}
static struct dmi_system_id __cpuinitdata processor_idle_dmi_table[] = {
{
set_no_mwait, "IFL91 board", {
DMI_MATCH(DMI_BIOS_VENDOR, "COMPAL"),
DMI_MATCH(DMI_SYS_VENDOR, "ZEPTO"),
DMI_MATCH(DMI_PRODUCT_VERSION, "3215W"),
DMI_MATCH(DMI_BOARD_NAME, "IFL91") }, NULL},
{
set_no_mwait, "Extensa 5220", {
DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies LTD"),
DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
DMI_MATCH(DMI_PRODUCT_VERSION, "0100"),
DMI_MATCH(DMI_BOARD_NAME, "Columbia") }, NULL},
{},
};
/*
* _PDC is required for a BIOS-OS handshake for most of the newer
* ACPI processor features.
*/
static int acpi_processor_eval_pdc(struct acpi_processor *pr)
{
struct acpi_object_list *pdc_in = pr->pdc;
acpi_status status = AE_OK;
if (!pdc_in)
return status;
if (idle_nomwait) {
/*
* If mwait is disabled for CPU C-states, the C2C3_FFH access
* mode will be disabled in the parameter of _PDC object.
* Of course C1_FFH access mode will also be disabled.
*/
union acpi_object *obj;
u32 *buffer = NULL;
obj = pdc_in->pointer;
buffer = (u32 *)(obj->buffer.pointer);
buffer[2] &= ~(ACPI_PDC_C_C2C3_FFH | ACPI_PDC_C_C1_FFH);
}
status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);
if (ACPI_FAILURE(status))
ACPI_DEBUG_PRINT((ACPI_DB_INFO,
"Could not evaluate _PDC, using legacy perf. control.\n"));
return status;
}
void acpi_processor_set_pdc(struct acpi_processor *pr)
{
if (arch_has_acpi_pdc() == false)
return;
arch_acpi_processor_init_pdc(pr);
acpi_processor_eval_pdc(pr);
arch_acpi_processor_cleanup_pdc(pr);
}
EXPORT_SYMBOL_GPL(acpi_processor_set_pdc);
static acpi_status
early_init_pdc(acpi_handle handle, u32 lvl, void *context, void **rv)
{
struct acpi_processor pr;
pr.handle = handle;
/* x86 implementation looks at pr.id to determine some
* CPU capabilites. We can just hard code to 0 since we're
* assuming the CPUs in the system are homogenous and all
* have the same capabilities.
*/
pr.id = 0;
acpi_processor_set_pdc(&pr);
return AE_OK;
}
void acpi_early_processor_set_pdc(void)
{
/*
* Check whether the system is DMI table. If yes, OSPM
* should not use mwait for CPU-states.
*/
dmi_check_system(processor_idle_dmi_table);
acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT,
ACPI_UINT32_MAX,
early_init_pdc, NULL, NULL, NULL);
}