Add support for calling deferred functions

This is a cleaner way of deferring work from interrupt-time to
task-time without requiring a task for each module which needs this.

Replaces/supersedes delayed hook notification, which didn't scale well
(since every function would have needed to be its own hook type).

BUG=chrome-os-partner:18473
BRANCH=none
TEST=boot system.  plug/unplug AC power; notifies the host properly

Change-Id: I50263fe1ce37e74c1ef8db3671379098997102ed
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/46953
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

1 files changed, 41 insertions, 0 deletions

diff --git a/include/hooks.h b/include/hooks.h
index c07877feca..6a6bd797cc 100644
--- a/include/hooks.h
+++ b/include/hooks.h
@@ -124,6 +124,11 @@ struct hook_data {
 };
 
 /**
+ * Initialize the hooks library.
+ */
+void hook_init(void);
+
+/**
  * Call all the hook routines of a specified type.
  *
  * @param type		Type of hook routines to call.
@@ -131,6 +136,23 @@ struct hook_data {
 void hook_notify(enum hook_type type);
 
 /**
+ * Start a timer to call a deferred routine.
+ *
+ * The routine will be called after at least the specified delay, in the
+ * context of the hook task.
+ *
+ * @param routine	Routine to call; must have been declared with
+ *			DECLARE_DEFERRED().
+ * @param us		Delay in microseconds until routine will be called.
+ *			If the routine is already pending, subsequent calls
+ *			will change the delay.  Pass us=0 to call as soon as
+ *			possible, or -1 to cancel the deferred call.
+ *
+ * @return non-zero if error.
+ */
+int hook_call_deferred(void (*routine)(void), int us);
+
+/**
  * Register a hook routine.
  *
  * @param hooktype	Type of hook for routine (enum hook_type)
@@ -146,4 +168,23 @@ void hook_notify(enum hook_type type);
 	__attribute__((section(".rodata." #hooktype)))			\
 	     = {routine, priority}
 
+
+struct deferred_data {
+	/* Deferred function pointer */
+	void (*routine)(void);
+};
+
+/**
+ * Register a deferred function call.
+ *
+ * Note that if you declare a bunch of these, you may need to override
+ * DEFERRABLE_MAX_COUNT in your board.h.
+ *
+ * @param routine	Function pointer, with prototype void routine(void)
+ */
+#define DECLARE_DEFERRED(routine)					\
+	const struct deferred_data __deferred_##routine			\
+	__attribute__((section(".rodata.deferred")))			\
+	     = {routine}
+
 #endif  /* __CROS_EC_HOOKS_H */