initial commit of lk (little kernel) project
diff --git a/kernel/dpc.c b/kernel/dpc.c
new file mode 100644
index 0000000..d4c2078
--- /dev/null
+++ b/kernel/dpc.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2008 Travis Geiselbrecht
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files
+ * (the "Software"), to deal in the Software without restriction,
+ * including without limitation the rights to use, copy, modify, merge,
+ * publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+ * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+ * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+ * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+ * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <debug.h>
+#include <list.h>
+#include <malloc.h>
+#include <err.h>
+#include <kernel/dpc.h>
+#include <kernel/thread.h>
+#include <kernel/event.h>
+
+struct dpc {
+ struct list_node node;
+
+ dpc_callback cb;
+ void *arg;
+};
+
+static struct list_node dpc_list = LIST_INITIAL_VALUE(dpc_list);
+static event_t dpc_event;
+
+static int dpc_thread_routine(void *arg);
+
+void dpc_init(void)
+{
+ event_init(&dpc_event, false, 0);
+
+ thread_resume(thread_create("dpc", &dpc_thread_routine, NULL, DPC_PRIORITY, DEFAULT_STACK_SIZE));
+}
+
+status_t dpc_queue(dpc_callback cb, void *arg, uint flags)
+{
+ struct dpc *dpc;
+
+ dpc = malloc(sizeof(struct dpc));
+
+ dpc->cb = cb;
+ dpc->arg = arg;
+ enter_critical_section();
+ list_add_tail(&dpc_list, &dpc->node);
+ event_signal(&dpc_event, (flags & DPC_FLAG_NORESCHED) ? false : true);
+ exit_critical_section();
+
+ return NO_ERROR;
+}
+
+static int dpc_thread_routine(void *arg)
+{
+ for (;;) {
+ event_wait(&dpc_event);
+
+ enter_critical_section();
+ struct dpc *dpc = list_remove_head_type(&dpc_list, struct dpc, node);
+ if (!dpc)
+ event_unsignal(&dpc_event);
+ exit_critical_section();
+
+ if (dpc) {
+// dprintf("dpc calling %p, arg %p\n", dpc->cb, dpc->arg);
+ dpc->cb(dpc->arg);
+
+ free(dpc);
+ }
+ }
+}
+
+