From 95d1eb6d381b3eeaf0a8c3de57d5ee554229bcd6 Mon Sep 17 00:00:00 2001
From: Aleksa Vuckovic <aleksav013@gmail.com>
Date: Tue, 24 Jan 2023 01:55:35 +0100
Subject: parsing RSDP & MADT

---
 kernel/src/apic/rsdp.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 kernel/src/apic/rsdp.c

(limited to 'kernel/src/apic/rsdp.c')

diff --git a/kernel/src/apic/rsdp.c b/kernel/src/apic/rsdp.c
new file mode 100644
index 0000000..ebecd66
--- /dev/null
+++ b/kernel/src/apic/rsdp.c
@@ -0,0 +1,68 @@
+#include <rsdp.h>
+#include <heap.h>
+#include <paging.h>
+#include <libk/string.h>
+#include <libk/stdio.h>
+
+uint64_t* find_rsdp()
+{
+	map_addr(0x0, 0x0, FLAG_PRESENT);
+	const char* rsdp_cs = "RSD PTR ";
+	for (uint64_t i = 0x10; i < 0x100000; i += 0x10) {
+		char *x = (char*)i;
+		uint8_t ind = 1;
+		for (size_t j = 0; j < strlen(rsdp_cs); j++) {
+			if (rsdp_cs[j] != x[j]) {
+				ind = 0;
+				break;
+			}
+		}
+		if (ind) {
+			return (uint64_t*)i;
+		}
+	}
+	return NULL;
+}
+
+uint64_t* find_sys_table_addr(const char* signature)
+{
+	uint64_t* rsdp = find_rsdp();
+
+	if (rsdp == NULL) {
+		printf("RSDP NOT FOUND\n");
+		return NULL;
+	}
+
+	struct RSDP_descriptor* rsdp_desc = (struct RSDP_descriptor*)rsdp;
+	map_addr(rsdp_desc->RsdtAddress, rsdp_desc->RsdtAddress, FLAG_PRESENT);
+
+	struct ACPI_header* rsdt = (struct ACPI_header*)kalloc(sizeof(struct ACPI_header));
+	memcpy(rsdt, (uint64_t*)(uint64_t)rsdp_desc->RsdtAddress, sizeof(struct ACPI_header));
+
+	uint32_t entries = (rsdt->Length - (uint32_t)sizeof(struct ACPI_header)) / 4;
+
+	for (size_t i = 0; i < entries; i++) {
+		uint32_t na_addr = (uint32_t)rsdp_desc->RsdtAddress + (uint32_t)sizeof(struct ACPI_header) + (uint32_t)i * 4;
+		uint32_t addr;
+		memcpy(&addr, (uint64_t*)(uint64_t)na_addr, 4);
+
+		struct ACPI_header* t = (struct ACPI_header*)kalloc(sizeof(struct ACPI_header));
+		memcpy(t, (uint64_t*)(uint64_t)addr, sizeof(struct ACPI_header));
+
+		int ind = 1;
+		for (size_t j = 0; j < 4; j++) {
+			if (t->Signature[j] != signature[j])
+				ind = 0;
+		}
+		if (ind) {
+			kfree(t);
+			kfree(rsdt);
+			return (uint64_t*)(uint64_t)addr;
+		}
+
+		kfree(t);
+	}
+
+	kfree(rsdt);
+	return NULL;
+}
-- 
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