x86: add irq support

kernel/irq.c

@@ -0,0 +1,83 @@
+/* See the end of this file for copyright and license terms. */
+
+#include <arch/irq.h>
+
+#include <gay/config.h>
+#include <gay/errno.h>
+#include <gay/irq.h>
+#include <gay/kprintf.h>
+
+void (*irq_table[NUM_IRQ])(void);
+
+#if CFG_DEBUG_IRQ
+	/*
+	 * If CFG_DEBUG_IRQ is set, the IRQ entry points pass the IRQ number
+	 * as an argument to the IRQ handler (see arch/<arch>/sys/irq.S).
+	 */
+	static void do_unknown_irq(unsigned int number)
+	{
+		kprintf("Unknown IRQ %d encountered!\n", number);
+	}
+#	define UNKNOWN_IRQ_HANDLER ((void (*)(void))do_unknown_irq)
+#else
+	static void do_unknown_irq(void)
+	{
+		kprintf("Unknown IRQ encountered!\n");
+	}
+#	define UNKNOWN_IRQ_HANDLER (do_unknown_irq)
+#endif
+
+void irq_init(void)
+{
+	for (unsigned int i = 0; i < NUM_IRQ; i++)
+		irq_table[i] = UNKNOWN_IRQ_HANDLER;
+	arch_irq_init();
+}
+
+int irq_enable(unsigned int number)
+{
+	if (number >= NUM_IRQ)
+		return -ERANGE;
+	if (irq_table[number] == UNKNOWN_IRQ_HANDLER)
+		return -ENOENT;
+
+	arch_irq_enable(number);
+	return 0;
+}
+
+void irq_disable(unsigned int number)
+{
+	if (number < NUM_IRQ)
+		arch_irq_disable(number);
+}
+
+int irq_attach(unsigned int number, void (*handler)(void))
+{
+	if (number >= NUM_IRQ)
+		return -ERANGE;
+	if (irq_table[number] != UNKNOWN_IRQ_HANDLER)
+		return -EEXIST;
+
+	irq_table[number] = handler;
+	return 0;
+}
+
+void irq_detach(unsigned int number)
+{
+	if (number < NUM_IRQ)
+		irq_table[number] = UNKNOWN_IRQ_HANDLER;
+}
+
+/*
+ * This file is part of GayBSD.
+ * Copyright (c) 2021 fef <owo@fef.moe>.
+ *
+ * GayBSD is nonviolent software: you may only use, redistribute, and/or
+ * modify it under the terms of the Cooperative Nonviolent Public License
+ * (CNPL) as found in the LICENSE file in the source code root directory
+ * or at <https://git.pixie.town/thufie/npl-builder>; either version 7
+ * of the license, or (at your option) any later version.
+ *
+ * GayBSD comes with ABSOLUTELY NO WARRANTY, to the extent
+ * permitted by applicable law.  See the CNPL for details.
+ */