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#include <acpi.h>
#include <stdint.h>
#include <printf.h>
#include <kernel.h>
#include <stdbool.h>
#include <kernel.h>
#include <io.h>
#include <int.h>
#include <libc.h>
#include <panic.h>
//finding rsdp
typedef struct rsdp {
char sig[8];
uint8_t checksum;
char OEMID[6];
uint8_t revision;
uint32_t rsdt;
//these only exist on REV > 1
uint32_t len;
uint64_t xsdt;
uint8_t extended_checksum;
uint8_t reserved[3];
} __attribute__((packed)) root_sdp;
//root descriptor SDTs
struct rsdt {
sdt_head header;
uint32_t sdt_pointers[];
} __attribute__((packed));
struct xsdt {
sdt_head header;
uint64_t sdt_pointers[];
} __attribute__((packed));
root_sdp *rsdp;
void debug_acpi() {
sdt_head *sdt;
int sdt_i, sdt_cnt;
if(rsdp->revision) {
struct xsdt *root = PHYS_TO_VIRT(rsdp->xsdt);
sdt_cnt = (root->header.length - sizeof(root->header)) / 8;
printf("sdts found in apic headers: %i\n", sdt_cnt);
for(sdt_i = 0; sdt_i < sdt_cnt; sdt_i++) {
sdt = PHYS_TO_VIRT(root->sdt_pointers[sdt_i]);
printf("ACPI debug:%.4s\n", sdt->sig);
}
}
else {
struct rsdt *root = PHYS_TO_VIRT((uint64_t)rsdp->rsdt);
sdt_cnt = (root->header.length - sizeof(root->header)) / 4;
printf("sdts found in apic headers: %i\n", sdt_cnt);
for(sdt_i = 0; sdt_i < sdt_cnt; sdt_i++) {
sdt = PHYS_TO_VIRT((uint64_t)root->sdt_pointers[sdt_i]);
printf("ACPI debug:%.4s\n", sdt->sig);
}
}
}
//TODO clean up confusing variable name rsdt
void *find_sdt(int type) {
char sig[4];
sdt_head *sdt;
int sdt_i, sdt_cnt;
//If we never need to expand this, then you can clean it up.
switch(type) {
case SDT_MADT:
strcpy(sig, "APIC");
break;
case SDT_HPET:
strcpy(sig, "HPET");
break;
}
if(rsdp->revision) {
struct xsdt *root = PHYS_TO_VIRT(rsdp->xsdt);
sdt_cnt = (root->header.length - sizeof(root->header)) / 8;
for(sdt_i = 0; sdt_i < sdt_cnt - 1; sdt_i++) {
sdt = PHYS_TO_VIRT((uint64_t)root->sdt_pointers[sdt_i]);
if(!(strncmp(sdt->sig, sig, 4))) {
return sdt;
}
}
}
else {
struct rsdt *root = PHYS_TO_VIRT((uint64_t)rsdp->rsdt);
sdt_cnt = (root->header.length - sizeof(root->header)) / 4;
for(sdt_i = 0; sdt_i < sdt_cnt - 1; sdt_i++) {
sdt = PHYS_TO_VIRT((uint64_t)root->sdt_pointers[sdt_i]);
if(!(strncmp(sdt->sig, sig, 4))) {
return sdt;
}
}
}
return 0;
}
bool verify_sdt(sdt_head *sdt) {
uint8_t checksum = 0;
for(int i = 0; i < sdt->length; i++) checksum += ((uint8_t *)sdt)[i];
return checksum == 0;
}
static root_sdp *verify_sdp(root_sdp *uv_rsdp) {
char *rsdp_char_ptr = (char *)uv_rsdp;
int i;
uint8_t checksum = 0;
if(uv_rsdp->revision) {
for(i = 0; i < uv_rsdp->len; i++) {
checksum += rsdp_char_ptr[i];
}
}
else {
for(i = 0; i <= 20; i++) {
checksum += rsdp_char_ptr[i];
}
}
if(!checksum) {
printf("Found RSDP revision %i at address %x.\n", uv_rsdp->revision, uv_rsdp);
return uv_rsdp;
}
printf("Skipped over invalid RSDP at 0x%p.\n", uv_rsdp);
return 0;
}
void find_root_sdp() {
const char sig[9] = "RSD PTR ";
uintptr_t *p = (void *)0x040e;
uintptr_t *ebda_unshifted = (void *)p;
bool rsdt_verified;
void *ebda = PHYS_TO_VIRT((void *)((uintptr_t)ebda_unshifted << (uintptr_t)4 & (uintptr_t)0xfffff));
for(void *i = ebda; i <= ebda + 64000; i += 16)
if(!(memcmp(sig, i, 8)) && ((rsdp = verify_sdp(i)))) break;
for(void *i = PHYS_TO_VIRT(0xe0000); i <= PHYS_TO_VIRT(0xfffff); i += 16)
if(!(memcmp(sig, i, 8)) && ((rsdp = verify_sdp(i)))) break;
if(!(rsdp)) {
printf("Couldn't find the RSDP... not sure what to do now.\n");
PANIC(KERNEL_PANIC_RSDP_UNFOUND);
}
if(rsdp->revision) {
rsdt_verified = verify_sdt(PHYS_TO_VIRT(rsdp->xsdt));
}
else {
rsdt_verified = verify_sdt(PHYS_TO_VIRT((uint64_t)rsdp->rsdt));
}
if(!(rsdt_verified)) {
PANIC(KERNEL_PANIC_INVALID_RSDT);
}
}
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