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// SPDX-License-Identifier: GPL-2.0
/*
* Utility functions for ACPI
*
* Copyright 2023 Google LLC
*/
#include <mapmem.h>
#include <acpi/acpi_table.h>
#include <asm/global_data.h>
DECLARE_GLOBAL_DATA_PTR;
struct acpi_table_header *acpi_find_table(const char *sig)
{
struct acpi_rsdp *rsdp;
struct acpi_rsdt *rsdt;
struct acpi_xsdt *xsdt;
int len, i, count;
rsdp = map_sysmem(gd_acpi_start(), 0);
if (!rsdp)
return NULL;
if (rsdp->xsdt_address) {
xsdt = nomap_sysmem(rsdp->xsdt_address, 0);
len = xsdt->header.length - sizeof(xsdt->header);
count = len / sizeof(u64);
} else {
if (!rsdp->rsdt_address)
return NULL;
rsdt = nomap_sysmem(rsdp->rsdt_address, 0);
len = rsdt->header.length - sizeof(rsdt->header);
count = len / sizeof(u32);
}
for (i = 0; i < count; i++) {
struct acpi_table_header *hdr;
if (rsdp->xsdt_address)
hdr = nomap_sysmem(xsdt->entry[i], 0);
else
hdr = nomap_sysmem(rsdt->entry[i], 0);
if (!memcmp(hdr->signature, sig, ACPI_NAME_LEN))
return hdr;
if (!memcmp(hdr->signature, "FACP", ACPI_NAME_LEN)) {
struct acpi_fadt *fadt = (struct acpi_fadt *)hdr;
if (!memcmp(sig, "DSDT", ACPI_NAME_LEN) && fadt->dsdt)
return nomap_sysmem(fadt->dsdt, 0);
if (!memcmp(sig, "FACS", ACPI_NAME_LEN) &&
fadt->firmware_ctrl)
return nomap_sysmem(fadt->firmware_ctrl, 0);
}
}
return NULL;
}
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