118 lines
3.0 KiB
C
118 lines
3.0 KiB
C
#include <kernel/acpi.h>
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#include <kernel/strcmp.h>
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#include <kernel/vga.h>
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#include <kernel/printf.h>
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#include <kernel/kernel.h>
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struct rsdp *acpi_locate_rsdp() {
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char *ptr = (char *)BIOS_START;
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char *str = RSDP_SIG;
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while ((uint32_t)ptr <= (uint32_t)BIOS_END - RSDP_SIG_LEN) {
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int i;
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for (i = 0; i < RSDP_SIG_LEN; i++) {
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if (ptr[i] != str[i])
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break;
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}
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if (i == RSDP_SIG_LEN) {
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return (struct rsdp *)ptr;
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}
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ptr++;
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}
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return 0;
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}
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int acpi_validate_rsdp_checksum(struct rsdp *s) {
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uint8_t *bytes = (uint8_t *)s;
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uint8_t sum = 0;
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for (int i = 0; i < RSDP_SIZE; i++) {
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sum += bytes[i];
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}
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return (sum & 0x0F) == 0;
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}
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int acpi_validate_sdt_checksum(struct ACPISDTHeader *s) {
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uint8_t sum = 0;
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for (uint32_t i = 0; i < s->Length; i++) {
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sum += ((char *)s)[i];
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}
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return sum == 0;
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}
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void *acpi_locate_sdt(struct rsdt *rsdt, const char sig[4]) {
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int entries = (rsdt->h.Length - sizeof(rsdt->h)) / 4;
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for (int i = 0; i < entries; i++)
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{
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struct ACPISDTHeader *h = (struct ACPISDTHeader *) rsdt->other_sdt[i];
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if (!strncmp(h->Signature, sig, 4)) {
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if (acpi_validate_sdt_checksum(h))
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return (void *) h;
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else
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return 0;
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}
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}
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return 0;
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}
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int acpi_init(struct kernel_context *ctx) {
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struct rsdp *found_rsdp = acpi_locate_rsdp();
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if (!found_rsdp) {
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set_color(VGA_COLOR_RED);
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printf("Failed to find RSDP signature\n");
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return 0;
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}
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if (found_rsdp->Revision == ACPI_VER_1) {
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if (!acpi_validate_rsdp_checksum(found_rsdp)) {
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set_color(VGA_COLOR_RED);
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printf("RSDP has an invalid checksum\n");
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return 0;
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}
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ctx->rsdp = found_rsdp;
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ctx->xsdp = 0;
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if (!acpi_validate_sdt_checksum((struct ACPISDTHeader *)found_rsdp->RsdtAddress)) {
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set_color(VGA_COLOR_RED);
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printf("RSDT has an invalid checksum\n");
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return 0;
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}
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ctx->rsdt = (struct rsdt*)found_rsdp->RsdtAddress;
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} else if (found_rsdp->Revision == ACPI_VER_OTHER) {
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set_color(VGA_COLOR_RED);
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printf("ACPI versions higher than 1.0 are not yet supported because I'm lazy\n");
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return 0;
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} else {
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set_color(VGA_COLOR_RED);
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printf("Invalid RSDP\n");
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return 0;
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}
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printf("[KERNEL] Using ACPI v1.0\n");
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struct fadt *fadt = acpi_locate_sdt(ctx->rsdt, "FACP");
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if (!fadt) {
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set_color(VGA_COLOR_RED);
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printf("Failed to find FADT\n");
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return 0;
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}
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printf("[KERNEL] Found FADT at 0x%x\n", fadt);
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if (fadt->Flags & 1)
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printf("[KERNEL] Legacy devices are supported\n");
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else {
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/*
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set_color(VGA_COLOR_RED);
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printf("Legacy devices are not supported. I'm too lazy to support modern devices, bye bye.\n");
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goto halt;
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*/
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}
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return 1;
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}
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