From a7577d19215144ac9d01f71de9093d86427fe66a Mon Sep 17 00:00:00 2001
From: Ian Moffett <ian@mirocom.org>
Date: Thu, 23 Apr 2026 22:28:24 -0400
Subject: [PATCH] sp1/amd64: io: Add IRQ chip manager groundwork

Signed-off-by: Ian Moffett <ian@mirocom.org>
---
 usr/src/sp1/amd64/io/irqchip.c         | 96 ++++++++++++++++++++++++++
 usr/src/sp1/common/io/acpi/acpi_init.c |  3 +
 usr/src/sp1/head/amd64/irqchip.h       | 22 ++++++
 3 files changed, 121 insertions(+)
 create mode 100644 usr/src/sp1/amd64/io/irqchip.c
 create mode 100644 usr/src/sp1/head/amd64/irqchip.h

diff --git a/usr/src/sp1/amd64/io/irqchip.c b/usr/src/sp1/amd64/io/irqchip.c
new file mode 100644
index 0000000..14e4787
--- /dev/null
+++ b/usr/src/sp1/amd64/io/irqchip.c
@@ -0,0 +1,96 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * All rights reserved.
+ *
+ * The following sources are CONFIDENTIAL and PROPRIETARY
+ * property of Mirocom Laboratories. Unauthorized copying,
+ * use, distribution or modification of this file, in whole
+ * and in part, is strictly prohibited without the prior written
+ * consent from Mirocom Laboratories.
+ */
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <os/knot.h>
+#include <lib/printf.h>
+#include <machine/irqchip.h>
+#include <io/acpi/acpi.h>
+#include <io/acpi/tables.h>
+
+#define pr_trace(fmt, ...) \
+    printf("irqchip: " fmt, ##__VA_ARGS__)
+
+/* Online capable */
+#define LAPIC_ONLCAP BIT(1)
+
+/*
+ * Print information about a Local APIC unit
+ */
+static inline void
+irqchip_print_lapic(struct local_apic *lapic)
+{
+    static uint16_t log_count = 0;
+
+    if (lapic == NULL) {
+        return;
+    }
+
+    if ((log_count++) >= 4) {
+        pr_trace("....\n");
+        return;
+    }
+
+    pr_trace("lapic(%d).cpu       : %d\n",
+        lapic->apic_id, lapic->processor_id);
+}
+
+/*
+ * Print information about an I/O APIC unit
+ */
+static inline void
+irqchip_print_ioapic(struct ioapic *ioapic)
+{
+    if (ioapic == NULL) {
+        return;
+    }
+
+    pr_trace("ioapic(%d).gsi_base : %d\n",
+        ioapic->ioapic_id, ioapic->gsi_base);
+    pr_trace("ioapic(%d).mmio     : %p\n",
+        ioapic->ioapic_id, ioapic->ioapic_addr);
+}
+
+status_t
+md_irqchip_init(void)
+{
+    struct acpi_madt *madt;
+    struct local_apic *lapic;
+    struct ioapic *ioapic;
+    struct apic_header *hdr;
+    char *cur, *end;
+
+    madt = acpi_query("APIC");
+    if (madt == NULL) {
+        knot("could not query acpi madt table\n");
+    }
+
+    cur = (char *)(madt + 1);
+    end = (char *)madt + madt->hdr.length;
+
+    while (cur < end) {
+        hdr = (struct apic_header *)cur;
+
+        switch (hdr->type) {
+        case APIC_TYPE_LOCAL_APIC:
+            lapic = (struct local_apic *)hdr;
+            irqchip_print_lapic(lapic);
+            break;
+        case APIC_TYPE_IO_APIC:
+            ioapic = (struct ioapic *)hdr;
+            irqchip_print_ioapic(ioapic);
+            break;
+        }
+
+        cur += hdr->length;
+    }
+}
diff --git a/usr/src/sp1/common/io/acpi/acpi_init.c b/usr/src/sp1/common/io/acpi/acpi_init.c
index f1b1ff1..f304c34 100644
--- a/usr/src/sp1/common/io/acpi/acpi_init.c
+++ b/usr/src/sp1/common/io/acpi/acpi_init.c
@@ -16,6 +16,7 @@
 #include <os/bpt.h>
 #include <mm/vm.h>
 #include <string.h>
+#include <machine/irqchip.h>    /* shared */
 
 #define pr_trace(fmt, ...) \
     printf("acpi: " fmt, ##__VA_ARGS__)
@@ -101,4 +102,6 @@ acpi_init(void)
         root_sdt = pma_to_vma((uintptr_t)rsdp->xsdt_addr);
         root_sdt_entries = (root_sdt->hdr.length - sizeof(root_sdt->hdr)) / 8;
     }
+
+    md_irqchip_init();
 }
diff --git a/usr/src/sp1/head/amd64/irqchip.h b/usr/src/sp1/head/amd64/irqchip.h
new file mode 100644
index 0000000..e57bbc8
--- /dev/null
+++ b/usr/src/sp1/head/amd64/irqchip.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2026, Mirocom Laboratories
+ * All rights reserved.
+ *
+ * The following sources are CONFIDENTIAL and PROPRIETARY
+ * property of Mirocom Laboratories. Unauthorized copying,
+ * use, distribution or modification of this file, in whole
+ * and in part, is strictly prohibited without the prior written
+ * consent from Mirocom Laboratories.
+ */
+
+#ifndef _MACHINE_IRQCHIP_H_
+#define _MACHINE_IRQCHIP_H_ 1
+
+#include <sys/status.h>
+
+/*
+ * Initialize platform interrupt controller chips
+ */
+status_t md_irqchip_init(void);
+
+#endif  /* !_MACHINE_IRQCHIP_H_ */