Merge branch '2022-03-09-events-subsystem' into nextnext

To quote the author:
It is a common need in U-Boot to have one subsystem notify another
when something happens. An example is reading a partition table when a
new block device is set up.

It is also common to add weak functions and 'hook' functions to modify
how U-Boot works. See for example ft_board_setup() and the like.

U-Boot would benefit from a generic mechanism to handle these cases,
with the ability to hook into various 'events' in a
subsystem-independent and transparent way.

This series provides a way to create and dispatch events, with a way of
registering a 'spy' which watches for events of different types. This
allows 'hook' functions to be created in a generic way.

It also includes a script to list the hooks in an image, which is a bit
easier to debug than weak functions, as well as an 'event' command to
do the same from within U-Boot.

These 'static' events can be used to replace hooks like misc_init_f(),
for example. Also included is basic support for 'dynamic' events, where
a spy can be registered at runtime. The need for this is still being
figured out.

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/sandbox/cpu/start.c b/arch/sandbox/cpu/start.c
index 13b0731..0f5a873 100644
--- a/arch/sandbox/cpu/start.c
+++ b/arch/sandbox/cpu/start.c
@@ -4,14 +4,14 @@
  */
 
 #include <common.h>
+#include <cli.h>
 #include <command.h>
-#include <dm/root.h>
 #include <efi_loader.h>
 #include <errno.h>
+#include <event.h>
 #include <init.h>
 #include <log.h>
 #include <os.h>
-#include <cli.h>
 #include <sort.h>
 #include <asm/getopt.h>
 #include <asm/global_data.h>
@@ -19,6 +19,7 @@
 #include <asm/malloc.h>
 #include <asm/sections.h>
 #include <asm/state.h>
+#include <dm/root.h>
 #include <linux/ctype.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -119,10 +120,11 @@ int sandbox_early_getopt_check(void)
 	os_exit(0);
 }
 
-int misc_init_f(void)
+static int sandbox_misc_init_f(void *ctx, struct event *event)
 {
 	return sandbox_early_getopt_check();
 }
+EVENT_SPY(EVT_MISC_INIT_F, sandbox_misc_init_f);
 
 static int sandbox_cmdline_cb_help(struct sandbox_state *state, const char *arg)
 {