From 3a72a201448fe16657a14cfc5916b672df94acf0 Mon Sep 17 00:00:00 2001
From: sigsegv7 <ian@vegaa.systems>
Date: Thu, 14 Sep 2023 00:22:21 -0400
Subject: kernel/amd64: Introduce initial I/O APIC support

Signed-off-by: sigsegv7 <ian@vegaa.systems>
---
 sys/firmware/acpi/acpi_init.c |   1 +
 sys/firmware/acpi/acpi_madt.c | 101 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 102 insertions(+)
 create mode 100644 sys/firmware/acpi/acpi_madt.c

(limited to 'sys/firmware/acpi')

diff --git a/sys/firmware/acpi/acpi_init.c b/sys/firmware/acpi/acpi_init.c
index a9c13ec..67c4d9c 100644
--- a/sys/firmware/acpi/acpi_init.c
+++ b/sys/firmware/acpi/acpi_init.c
@@ -106,4 +106,5 @@ acpi_init(void)
         panic("Root SDT has an invalid checksum!\n");
     }
     root_sdt_entries = (root_sdt->hdr.length - sizeof(root_sdt->hdr)) / 4;
+    acpi_parse_madt();
 }
diff --git a/sys/firmware/acpi/acpi_madt.c b/sys/firmware/acpi/acpi_madt.c
new file mode 100644
index 0000000..fde5dde
--- /dev/null
+++ b/sys/firmware/acpi/acpi_madt.c
@@ -0,0 +1,101 @@
+/*
+ * Copyright (c) 2023 Ian Marco Moffett and the VegaOS 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 VegaOS 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 <firmware/acpi/acpi.h>
+#include <firmware/acpi/tables.h>
+#include <machine/ioapic.h>
+#include <sys/cdefs.h>
+#include <sys/panic.h>
+#include <sys/syslog.h>
+
+#define APIC_TYPE_LOCAL_APIC            0
+#define APIC_TYPE_IO_APIC               1
+#define APIC_TYPE_INTERRUPT_OVERRIDE    2
+
+__MODULE_NAME("acpi");
+__KERNEL_META("$Vega$: acpi_madt.c, Ian Marco Moffett, "
+              "ACPI MADT parsing");
+
+static struct acpi_madt *madt = NULL;
+
+static void
+do_parse(void)
+{
+    uint8_t *cur = NULL;
+    uint8_t *end = NULL;
+
+    struct apic_header *hdr = NULL;
+    struct ioapic *ioapic = NULL;
+    void *ioapic_mmio_base = NULL;
+
+    cur = (uint8_t *)(madt + 1);
+    end = (uint8_t *)madt + madt->hdr.length;
+
+    while (cur < end) {
+        hdr = (void *)cur;
+
+        switch (hdr->type) {
+        case APIC_TYPE_IO_APIC:
+            /*
+             * TODO: Figure out how to use multiple
+             *       I/O APICs.
+             */
+            if (ioapic != NULL) {
+                break;
+            }
+
+            ioapic = (struct ioapic *)cur;
+
+            KINFO("Detected I/O APIC (id=%d, gsi_base=%d)\n",
+                  ioapic->ioapic_id, ioapic->gsi_base);
+
+            ioapic_mmio_base = (void *)(uintptr_t)ioapic->ioapic_addr;
+            ioapic_set_base(ioapic_mmio_base);
+            break;
+        }
+
+        cur += hdr->length;
+    }
+}
+
+void
+acpi_parse_madt(void)
+{
+    /* Prevent this function from running twice */
+    if (madt != NULL) {
+        return;
+    }
+
+    madt = acpi_query("APIC");
+    if (madt == NULL) {
+        panic("Failed to query for ACPI MADT\n");
+    }
+
+    do_parse();
+}
-- 
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