4 files changed, 82 insertions, 0 deletions
diff --git a/sys/arch/amd64/amd64/acpi_machdep.c b/sys/arch/amd64/amd64/acpi_machdep.c
new file mode 100644
index 0000000..5f3b3bf
--- /dev/null
+++ b/sys/arch/amd64/amd64/acpi_machdep.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of Hyra nor the names of its
+ *    contributors may be used to endorse or promote products derived from
+ *    this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/panic.h>
+#include <sys/syslog.h>
+#include <dev/acpi/acpi.h>
+#include <dev/acpi/acpivar.h>
+#include <dev/acpi/tables.h>
+
+#define pr_trace(fmt, ...) kprintf("acpi: " fmt, ##__VA_ARGS__)
+
+int
+acpi_init_madt(void)
+{
+    struct acpi_madt *madt = acpi_query("APIC");
+    struct apic_header *apichdr;
+    struct ioapic *ioapic = NULL;
+    uint8_t *cur, *end;
+
+    if (madt == NULL) {
+        panic("Could not find MADT!\n");
+    }
+
+    cur = (uint8_t *)(madt + 1);
+    end = (uint8_t *)madt + madt->hdr.length;
+
+    while (cur < end) {
+        apichdr = (void *)cur;
+        if (apichdr->type == APIC_TYPE_IO_APIC) {
+            /*
+             * TODO: Figure out how to use multiple I/O APICs
+             */
+            if (ioapic != NULL) {
+                pr_trace("Skipping I/O APIC with ID %d\n", ioapic->ioapic_id);
+                break;
+            }
+
+            ioapic = (struct ioapic *)cur;
+            pr_trace("Detected I/O APIC (id=%d, gsi_base=%d)\n",
+                ioapic->ioapic_id, ioapic->gsi_base);
+        }
+
+        cur += apichdr->length;
+    }
+
+    return 0;
+
+}
diff --git a/sys/dev/acpi/acpi_init.c b/sys/dev/acpi/acpi_init.c
index f445d95..4c0ae1b 100644
--- a/sys/dev/acpi/acpi_init.c
+++ b/sys/dev/acpi/acpi_init.c
@@ -118,4 +118,5 @@ acpi_init(void)
 
     root_sdt_entries = (root_sdt->hdr.length - sizeof(root_sdt->hdr)) / 4;
     acpi_init_hpet();
+    acpi_init_madt();
 }
diff --git a/sys/include/dev/acpi/acpivar.h b/sys/include/dev/acpi/acpivar.h
index 9a37dfb..9cfe945 100644
--- a/sys/include/dev/acpi/acpivar.h
+++ b/sys/include/dev/acpi/acpivar.h
@@ -35,6 +35,8 @@
 
 uint8_t acpi_checksum(struct acpi_header *hdr);
 struct acpi_root_sdt *acpi_get_root_sdt(void);
+
 size_t acpi_get_root_sdt_len(void);
+int acpi_init_madt(void);
 
 #endif  /* !_ACPI_ACPIVAR_H_ */
diff --git a/sys/include/dev/acpi/tables.h b/sys/include/dev/acpi/tables.h
index d5bfd52..1dca890 100644
--- a/sys/include/dev/acpi/tables.h
+++ b/sys/include/dev/acpi/tables.h
@@ -33,6 +33,11 @@
 #include <sys/types.h>
 #include <sys/cdefs.h>
 
+/* MADT APIC header types */
+#define APIC_TYPE_LOCAL_APIC            0
+#define APIC_TYPE_IO_APIC               1
+#define APIC_TYPE_INTERRUPT_OVERRIDE    2
+
 #define OEMID_SIZE 6
 
 struct __packed acpi_header {