1 files changed, 106 insertions, 0 deletions
diff --git a/include/lib/el3_runtime/pubsub.h b/include/lib/el3_runtime/pubsub.h
new file mode 100644
index 0000000..cbd8ecc
--- /dev/null
+++ b/include/lib/el3_runtime/pubsub.h
@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2017-2023, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef PUBSUB_H
+#define PUBSUB_H
+
+#ifdef __LINKER__
+
+/* For the linker ... */
+#define __pubsub_start_sym(event)	__pubsub_##event##_start
+#define __pubsub_end_sym(event)		__pubsub_##event##_end
+#define __pubsub_section(event)		.__pubsub_##event
+
+/*
+ * REGISTER_PUBSUB_EVENT has a different definition between linker and compiler
+ * contexts. In linker context, this collects pubsub sections for each event,
+ * placing guard symbols around each.
+ */
+#if defined(USE_ARM_LINK)
+#define REGISTER_PUBSUB_EVENT(event) \
+	__pubsub_start_sym(event) +0 FIXED \
+	{ \
+		*(__pubsub_section(event)) \
+	} \
+	__pubsub_end_sym(event) +0 FIXED EMPTY 0 \
+	{ \
+		/* placeholder */ \
+	}
+#else
+#define REGISTER_PUBSUB_EVENT(event) \
+	__pubsub_start_sym(event) = .; \
+	KEEP(*(__pubsub_section(event))); \
+	__pubsub_end_sym(event) = .
+#endif
+
+#else /* __LINKER__ */
+
+/* For the compiler ... */
+
+#include <assert.h>
+#include <cdefs.h>
+#include <stddef.h>
+
+#include <arch_helpers.h>
+
+#if defined(USE_ARM_LINK)
+#define __pubsub_start_sym(event)	Load$$__pubsub_##event##_start$$Base
+#define __pubsub_end_sym(event)		Load$$__pubsub_##event##_end$$Base
+#else
+#define __pubsub_start_sym(event)	__pubsub_##event##_start
+#define __pubsub_end_sym(event)		__pubsub_##event##_end
+#endif
+
+#define __pubsub_section(event)		__section(".__pubsub_" #event)
+
+/*
+ * In compiler context, REGISTER_PUBSUB_EVENT declares the per-event symbols
+ * exported by the linker required for the other pubsub macros to work.
+ */
+#define REGISTER_PUBSUB_EVENT(event) \
+	extern pubsub_cb_t __pubsub_start_sym(event)[]; \
+	extern pubsub_cb_t __pubsub_end_sym(event)[]
+
+/*
+ * Have the function func called back when the specified event happens. This
+ * macro places the function address into the pubsub section, which is picked up
+ * and invoked by the invoke_pubsubs() function via the PUBLISH_EVENT* macros.
+ *
+ * The extern declaration is there to satisfy MISRA C-2012 rule 8.4.
+ */
+#define SUBSCRIBE_TO_EVENT(event, func) \
+	extern pubsub_cb_t __cb_func_##func##event __pubsub_section(event); \
+	pubsub_cb_t __cb_func_##func##event __pubsub_section(event) = (func)
+
+/*
+ * Iterate over subscribed handlers for a defined event. 'event' is the name of
+ * the event, and 'subscriber' a local variable of type 'pubsub_cb_t *'.
+ */
+#define for_each_subscriber(event, subscriber) \
+	for (subscriber = __pubsub_start_sym(event); \
+			subscriber < __pubsub_end_sym(event); \
+			subscriber++)
+
+/*
+ * Publish a defined event supplying an argument. All subscribed handlers are
+ * invoked, but the return value of handlers are ignored for now.
+ */
+#define PUBLISH_EVENT_ARG(event, arg) \
+	do { \
+		pubsub_cb_t *subscriber; \
+		for_each_subscriber(event, subscriber) { \
+			(*subscriber)(arg); \
+		} \
+	} while (0)
+
+/* Publish a defined event with NULL argument */
+#define PUBLISH_EVENT(event)	PUBLISH_EVENT_ARG(event, NULL)
+
+/* Subscriber callback type */
+typedef void* (*pubsub_cb_t)(const void *arg);
+
+#endif	/* __LINKER__ */
+#endif /* PUBSUB_H */