kernel: DPC support

kernel-src/include/kernel/dpc.h

@@ -0,0 +1,22 @@
+#ifndef _DPC_H
+#define _DPC_H
+
+#include <arch/context.h>
+#include <stdbool.h>
+
+typedef void * dpcarg_t;
+typedef void (*dpcfn_t)(context_t *, dpcarg_t);
+
+typedef struct _dpc_t {
+	struct _dpc_t *next;
+	struct _dpc_t *prev;
+	bool enqueued;
+	dpcfn_t fn;
+	dpcarg_t arg;
+} dpc_t;
+
+void dpc_enqueue(dpc_t *dpc, dpcfn_t, dpcarg_t);
+void dpc_dequeue(dpc_t *dpc);
+void dpc_init();
+
+#endif

kernel-src/include/kernel/interrupt.h

@@ -15,6 +15,7 @@
 #define IPL_MAX 0
 #define IPL_TIMER 1
 #define IPL_KEYBOARD 2
+#define IPL_DPC 900
 #define IPL_NORMAL 1000
 
 struct _isr_t;