blob: cba9c24dd45daf2e9b86bda507e59187e8980f75 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0+
* Copyright (C) 2018, Bin Meng <>
#include <common.h>
#include <asm/acpi_table.h>
#include <asm/io.h>
#include <asm/tables.h>
static struct acpi_rsdp *acpi_valid_rsdp(struct acpi_rsdp *rsdp)
if (strncmp((char *)rsdp, RSDP_SIG, sizeof(RSDP_SIG) - 1) != 0)
return NULL;
debug("Looking on %p for valid checksum\n", rsdp);
if (table_compute_checksum((void *)rsdp, 20) != 0)
return NULL;
debug("acpi rsdp checksum 1 passed\n");
if ((rsdp->revision > 1) &&
(table_compute_checksum((void *)rsdp, rsdp->length) != 0))
return NULL;
debug("acpi rsdp checksum 2 passed\n");
return rsdp;
struct acpi_fadt *acpi_find_fadt(void)
char *p, *end;
struct acpi_rsdp *rsdp = NULL;
struct acpi_rsdt *rsdt;
struct acpi_fadt *fadt = NULL;
int i;
/* Find RSDP */
for (p = (char *)ROM_TABLE_ADDR; p < (char *)ROM_TABLE_END; p += 16) {
rsdp = acpi_valid_rsdp((struct acpi_rsdp *)p);
if (rsdp)
if (!rsdp)
return NULL;
debug("RSDP found at %p\n", rsdp);
rsdt = (struct acpi_rsdt *)(uintptr_t)rsdp->rsdt_address;
end = (char *)rsdt + rsdt->header.length;
debug("RSDT found at %p ends at %p\n", rsdt, end);
for (i = 0; ((char *)&rsdt->entry[i]) < end; i++) {
fadt = (struct acpi_fadt *)(uintptr_t)rsdt->entry[i];
if (strncmp((char *)fadt, "FACP", 4) == 0)
fadt = NULL;
if (!fadt)
return NULL;
debug("FADT found at %p\n", fadt);
return fadt;
void *acpi_find_wakeup_vector(struct acpi_fadt *fadt)
struct acpi_facs *facs;
void *wake_vec;
debug("Trying to find the wakeup vector...\n");
facs = (struct acpi_facs *)(uintptr_t)fadt->firmware_ctrl;
if (!facs) {
debug("No FACS found, wake up from S3 not possible.\n");
return NULL;
debug("FACS found at %p\n", facs);
wake_vec = (void *)(uintptr_t)facs->firmware_waking_vector;
debug("OS waking vector is %p\n", wake_vec);
return wake_vec;
void enter_acpi_mode(int pm1_cnt)
u16 val = inw(pm1_cnt);
* PM1_CNT register bit0 selects the power management event to be
* either an SCI or SMI interrupt. When this bit is set, then power
* management events will generate an SCI interrupt. When this bit
* is reset power management events will generate an SMI interrupt.
* Per ACPI spec, it is the responsibility of the hardware to set
* or reset this bit. OSPM always preserves this bit position.
* U-Boot does not support SMI. And we don't have plan to support
* anything running in SMM within U-Boot. To create a legacy-free
* system, and expose ourselves to OSPM as working under ACPI mode
* already, turn this bit on.
outw(val | PM1_CNT_SCI_EN, pm1_cnt);