Started ACPI driver

4 files changed, 99 insertions, 0 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 98060df..c6b6d93 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -1,6 +1,7 @@
 # MIT License, Copyright (c) 2020 Marvin Borner
 
 COBJS = main.o \
+	drivers/acpi.o \
 	drivers/interrupts.o \
 	drivers/interrupts_asm.o \
 	drivers/fpu.o \
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));
+}
diff --git a/kernel/inc/acpi.h b/kernel/inc/acpi.h
new file mode 100644
index 0000000..f620d55
--- /dev/null
+++ b/kernel/inc/acpi.h
@@ -0,0 +1,42 @@
+// MIT License, Copyright (c) 2020 Marvin Borner
+
+#ifndef ACPI_H
+#define ACPI_H
+
+#include <def.h>
+
+#define RSDP_MAGIC "RSD PTR "
+#define RSDT_MAGIC "RSDT"
+
+struct sdt_header {
+	char signature[4];
+	u32 length;
+	u8 revision;
+	u8 checksum;
+	char oem_id[6];
+	char oem_table_id[8];
+	u32 oem_revision;
+	u32 creator_id;
+	u32 creator_revision;
+};
+
+struct sdp_header {
+	char signature[8];
+	u8 checksum;
+	char oem_id[6];
+	u8 revision;
+};
+
+struct rsdt {
+	struct sdt_header header;
+	u32 sdt_pointer[];
+};
+
+struct rsdp {
+	struct sdp_header header;
+	struct rsdt *rsdt;
+};
+
+void acpi_install();
+
+#endif
diff --git a/kernel/main.c b/kernel/main.c
index 4792d75..34332e2 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -1,5 +1,6 @@
 // MIT License, Copyright (c) 2020 Marvin Borner
 
+#include <acpi.h>
 #include <boot.h>
 #include <cpu.h>
 #include <fpu.h>
@@ -23,6 +24,7 @@ void kernel_main(struct vid_info *vid_info)
 	serial_print("\nConnected.\n");
 
 	// Install drivers
+	acpi_install();
 	interrupts_install();
 	fpu_install();
 	timer_install();