Find RSD Table in early BIOS memory

Adding functions and structures to read the RSD.
This commit is contained in:
Nigel Barink 2021-12-24 20:13:28 +01:00
parent 2621399349
commit 72008b0a7a
2 changed files with 82 additions and 0 deletions

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#include "rsdp.h"
void printRSD(RSDPTR* rsd){
printf("Signature: ");
for(int i = 0; i < 8; i++){
kterm_put(rsd->signature[i]);
}
kterm_put('\n');
printf("OEMID: ");
for(int i =0; i < 6 ; i++){
kterm_put (rsd->OEMID[i]);
}
kterm_put('\n');
printf("Revision: %d\n", rsd->Revision);
printf("RSDT Address: 0x%x\n", rsd->RsdtAddress );
}
RSDPTR* FindRSD(){
char* memory_byte = (char*) 0x000f2e14;
const void* string = "RSD PTR ";
for( ; (uint32_t) memory_byte < 0x0100000; memory_byte+=10){
if( memcmp(memory_byte , string , 8 ) == 0 ) {
printf("RSD PTR found at 0x%x !\n", memory_byte);
break;
}
}
printRSD((RSDPTR*) memory_byte);
return (RSDPTR*) memory_byte;
}
RSDT* getRSDT(RSDPTR* rsd){
RSDT* rsdt = (RSDT*) rsd->RsdtAddress;
printf("OEMID: ");
for(int i = 0; i < 6; i++){
kterm_put(rsdt->header.OEMID[i]);
}
kterm_put('\n');
return rsdt;
}

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#pragma once
#include <stdint.h>
#include "./../../tty/kterm.h"
#include "../../../libc/include/mem.h"
struct RSDPTR {
char signature[8];
uint8_t Checksum ;
char OEMID [6];
uint8_t Revision;
uint32_t RsdtAddress;
}__attribute__((packed));
struct ACPISDTHeader{
char Signature[4];
uint32_t Length;
uint8_t CheckSum;
char OEMID[6];
char OEMTableID[8];
uint32_t OEMRevision;
uint32_t CreatorID;
uint32_t CreatorRevision;
}__attribute__((packed));
struct RSDT{
struct ACPISDTHeader header;
uint32_t PointerToSDT[]; // Length of array : (header.Length - sizeof(header))/ 4
}__attribute__((packed));
//NOTE: only scans EBDA enough to find RSD PTR in QEMU
RSDPTR* FindRSD();
void printRSD(RSDPTR* rsd);
RSDT* getRSDT(RSDPTR* rsd);