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// MIT License, Copyright (c) 2021 Marvin Borner
#include <acpi.h>
#include <lib.h>
#include <pnc.h>
/**
* General SDP
*/
static u8 acpi_sdp_verify(struct sdp_header *header)
{
u8 sum = 0;
for (u32 i = 0; i < sizeof(struct rsdp); i++)
sum += (u8)(((u8 *)header)[i]);
return sum == 0;
}
/**
* General SDT
*/
static u8 acpi_sdt_verify(struct sdt_header *header)
{
u8 sum = 0;
for (u32 i = 0; i < header->length; i++)
sum += (u8)(((u8 *)header)[i]);
return sum == 0;
}
static void *acpi_sdt_find(struct rsdt *rsdt, const char *signature)
{
u32 entries = (rsdt->header.length - sizeof(rsdt->header)) / 4;
for (u32 i = 0; i < entries; i++) {
struct sdt_header *header = (struct sdt_header *)rsdt->sdt_pointer[i];
if (memcmp(header->signature, signature, 4) == 0) {
if (acpi_sdt_verify(header))
return header;
else
break;
}
}
return NULL;
}
/**
* RSDP - points to RSDT
*/
static struct rsdp *acpi_rsdp_find(void)
{
// Main BIOS area
for (u32 i = 0xe0000; i < 0xfffff; i++)
if (memcmp((u32 *)i, RSDP_MAGIC, 8) == 0)
return (struct rsdp *)i;
// Or first KB of EBDA?
u8 *ebda = (void *)(*((u16 *)0x40e) << 4);
for (u16 i = 0; i < 1024; i += 16)
if (memcmp(ebda + i, RSDP_MAGIC, 8) == 0)
return (struct rsdp *)(ebda + i);
return NULL;
}
/**
* Probe
*/
void acpi_probe(void)
{
struct rsdp *rsdp = acpi_rsdp_find();
assert(rsdp && rsdp->header.revision == 0 && acpi_sdp_verify(&rsdp->header));
struct rsdt *rsdt = rsdp->rsdt;
assert(rsdt && memcmp(rsdt->header.signature, RSDT_MAGIC, 4) == 0 &&
acpi_sdt_verify(&rsdt->header));
struct madt *madt = acpi_sdt_find(rsdt, MADT_MAGIC);
struct fadt *fadt = acpi_sdt_find(rsdt, FADT_MAGIC);
struct hpet *hpet = acpi_sdt_find(rsdt, HPET_MAGIC);
// TODO!
UNUSED(madt);
UNUSED(fadt);
UNUSED(hpet);
}
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