Started ACPI driver

1 files changed, 54 insertions, 0 deletions

diff --git a/kernel/drivers/acpi.c b/kernel/drivers/acpi.c
new file mode 100644
index 0000000..02f3718
--- /dev/null
+++ b/kernel/drivers/acpi.c
@@ -0,0 +1,54 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#include <acpi.h>
+#include <assert.h>
+#include <cpu.h>
+#include <def.h>
+#include <mem.h>
+#include <print.h>
+
+int check_sdt(struct sdt_header *header)
+{
+	u8 sum = 0;
+
+	for (u32 i = 0; i < header->length; i++)
+		sum += ((char *)header)[i];
+
+	return sum == 0;
+}
+
+int check_sdp(struct sdp_header *header)
+{
+	u8 sum = 0;
+
+	for (u32 i = 0; i < sizeof(struct rsdp); i++)
+		sum += ((char *)header)[i];
+
+	return sum == 0;
+}
+
+struct rsdp *find_rsdp()
+{
+	// Main BIOS area
+	for (int i = 0xe0000; i < 0xfffff; i++) {
+		if (memcmp((u32 *)i, RSDP_MAGIC, 8) == 0)
+			return (struct rsdp *)i;
+	}
+
+	// Or first KB of EBDA?
+	for (int i = 0x100000; i < 0x101000; i++) {
+		if (memcmp((u32 *)i, RSDP_MAGIC, 8) == 0)
+			return (struct rsdp *)i;
+	}
+
+	return NULL;
+}
+
+void acpi_install()
+{
+	struct rsdp *rsdp = find_rsdp();
+	assert(rsdp && rsdp->header.revision == 0 && check_sdp(&rsdp->header));
+	struct rsdt *rsdt = rsdp->rsdt;
+	assert(rsdt && memcmp(rsdt->header.signature, RSDT_MAGIC, 4) == 0 &&
+	       check_sdt(&rsdt->header));
+}