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

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, 3 insertions, 1 deletions

diff --git a/arch/x86/cpu/baytrail/cpu.c b/arch/x86/cpu/baytrail/cpu.c
index 309a50a1161..68bf40ba8e8 100644
--- a/arch/x86/cpu/baytrail/cpu.c
+++ b/arch/x86/cpu/baytrail/cpu.c
@@ -8,6 +8,7 @@
 #include <common.h>
 #include <cpu.h>
 #include <dm.h>
+#include <event.h>
 #include <init.h>
 #include <log.h>
 #include <pci.h>
@@ -44,7 +45,7 @@ static void hsuart_clock_set(void *base)
  * Configure the internal clock of both SIO HS-UARTs, if they are enabled
  * via FSP
  */
-int arch_cpu_init_dm(void)
+static int baytrail_uart_init(void *ctx, struct event *event)
 {
 	struct udevice *dev;
 	void *base;
@@ -63,6 +64,7 @@ int arch_cpu_init_dm(void)
 
 	return 0;
 }
+EVENT_SPY(EVT_DM_POST_INIT, baytrail_uart_init);
 
 static void set_max_freq(void)
 {