3 files changed, 66 insertions, 5 deletions

diff --git a/kernel/drivers/acpi.c b/kernel/drivers/acpi.c
index f7f643c..999c0ed 100644
--- a/kernel/drivers/acpi.c
+++ b/kernel/drivers/acpi.c
@@ -50,8 +50,12 @@ void *find_sdt(struct rsdt *rsdt, const char *signature)
 
 	for (int i = 0; i < entries; i++) {
 		struct sdt_header *header = (struct sdt_header *)rsdt->sdt_pointer[i];
-		if (memcmp(header->signature, signature, 4) == 0)
-			return header;
+		if (memcmp(header->signature, signature, 4) == 0) {
+			if (check_sdt(header))
+				return header;
+			else
+				break;
+		}
 	}
 
 	return NULL;
@@ -68,6 +72,18 @@ void acpi_install()
 	madt = find_sdt(rsdt, MADT_MAGIC);
 	fadt = find_sdt(rsdt, FADT_MAGIC);
 	hpet = find_sdt(rsdt, HPET_MAGIC);
-	assert(madt && check_sdt(&madt->header) && fadt && check_sdt(&fadt->header) && hpet &&
-	       check_sdt(&hpet->header));
+}
+
+void hpet_install()
+{
+	if (hpet && hpet->legacy_replacement && hpet->comparator_count > 0) {
+		struct hpet_registers *r = (struct hpet_registers *)hpet->address.phys;
+		printf("HPET tick period: %dns\n", r->features.tick_period / 1000000);
+		printf("Periodic support: %d\n", r->timer.periodic_support);
+		r->config.enable = 1;
+		r->config.legacy_replacement = 1;
+		r->timer.enable = 1;
+	} else {
+		hpet = NULL;
+	}
 }
diff --git a/kernel/inc/acpi.h b/kernel/inc/acpi.h
index 2b4c76e..498384e 100644
--- a/kernel/inc/acpi.h
+++ b/kernel/inc/acpi.h
@@ -16,7 +16,7 @@ struct address_structure {
 	u8 register_bit_width;
 	u8 register_bit_offset;
 	u8 reserved;
-	u64 address;
+	u32 phys; // Actually u64
 };
 
 struct sdt_header {
@@ -68,6 +68,49 @@ struct hpet {
 	u8 page_protection;
 };
 
+struct hpet_registers {
+	struct {
+		u8 revision;
+		u8 comparator_count : 5;
+		u8 counter_size : 1;
+		u8 reserved : 1;
+		u8 legacy_replacement : 1;
+		u16 pci_vendor_id;
+		u32 tick_period;
+	} features;
+	u64 reserved1;
+	struct {
+		u8 enable : 1;
+		u8 legacy_replacement : 1;
+		u64 reserved : 62;
+	} config;
+	u64 reserved2;
+	struct {
+		u32 status; // For timer #n
+		u32 reserved;
+	} int_status;
+	u8 reserved3[200]; // Why?!
+	u32 counter;
+	u32 counter_high; // 0 due to 64 bit
+	u64 reserved4;
+	struct {
+		u8 reserved1 : 1;
+		u8 type : 1;
+		u8 enable : 1;
+		u8 periodic : 1;
+		u8 periodic_support : 1;
+		u8 size : 1; // 1 if 64 bit
+		u8 set_accumulator : 1;
+		u8 reserved2 : 1;
+		u8 force_32 : 1; // For 64 bit
+		u8 apic_routing : 5;
+		u8 fsb : 1;
+		u8 fsb_support : 1;
+		u16 reserved3;
+		u32 routing_capability;
+	} timer;
+};
+
 struct rsdp {
 	struct sdp_header header;
 	struct rsdt *rsdt;
@@ -78,5 +121,6 @@ struct fadt *fadt;
 struct hpet *hpet;
 
 void acpi_install();
+void hpet_install();
 
 #endif
diff --git a/kernel/main.c b/kernel/main.c
index 34332e2..fc304b2 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -25,6 +25,7 @@ void kernel_main(struct vid_info *vid_info)
 
 	// Install drivers
 	acpi_install();
+	hpet_install();
 	interrupts_install();
 	fpu_install();
 	timer_install();