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/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Events provide a general-purpose way to react to / subscribe to changes
* within U-Boot
*
* Copyright 2021 Google LLC
* Written by Simon Glass <sjg@chromium.org>
*/
#ifndef __event_h
#define __event_h
/**
* enum event_t - Types of events supported by U-Boot
*
* @EVT_DM_PRE_PROBE: Device is about to be probed
*/
enum event_t {
EVT_NONE,
EVT_TEST,
/* Events related to driver model */
EVT_DM_POST_INIT,
EVT_DM_PRE_PROBE,
EVT_DM_POST_PROBE,
EVT_DM_PRE_REMOVE,
EVT_DM_POST_REMOVE,
/* Init hooks */
EVT_MISC_INIT_F,
EVT_COUNT
};
union event_data {
/**
* struct event_data_test - test data
*
* @signal: A value to update the state with
*/
struct event_data_test {
int signal;
} test;
/**
* struct event_dm - driver model event
*
* @dev: Device this event relates to
*/
struct event_dm {
struct udevice *dev;
} dm;
};
/**
* struct event - an event that can be sent and received
*
* @type: Event type
* @data: Data for this particular event
*/
struct event {
enum event_t type;
union event_data data;
};
/** Function type for event handlers */
typedef int (*event_handler_t)(void *ctx, struct event *event);
/**
* struct evspy_info - information about an event spy
*
* @func: Function to call when the event is activated (must be first)
* @type: Event type
* @id: Event id string
*/
struct evspy_info {
event_handler_t func;
enum event_t type;
#if CONFIG_IS_ENABLED(EVENT_DEBUG)
const char *id;
#endif
};
/* Declare a new event spy */
#if CONFIG_IS_ENABLED(EVENT_DEBUG)
#define _ESPY_REC(_type, _func) { _func, _type, #_func, }
#else
#define _ESPY_REC(_type, _func) { _func, _type, }
#endif
static inline const char *event_spy_id(struct evspy_info *spy)
{
#if CONFIG_IS_ENABLED(EVENT_DEBUG)
return spy->id;
#else
return "?";
#endif
}
/*
* It seems that LTO will drop list entries if it decides they are not used,
* although the conditions that cause this are unclear.
*
* The example found is the following:
*
* 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);
*
* where EVENT_SPY uses ll_entry_declare()
*
* In this case, LTO decides to drop the sandbox_misc_init_f() function
* (which is fine) but then drops the linker-list entry too. This means
* that the code no longer works, in this case sandbox no-longer checks its
* command-line arguments properly.
*
* Without LTO, the KEEP() command in the .lds file is enough to keep the
* entry around. But with LTO it seems that the entry has already been
* dropped before the link script is considered.
*
* The only solution I can think of is to mark linker-list entries as 'used'
* using an attribute. This should be safe, since we don't actually want to drop
* any of these. However this does slightly limit LTO's optimisation choices.
*/
#define EVENT_SPY(_type, _func) \
static __attribute__((used)) ll_entry_declare(struct evspy_info, \
_type, evspy_info) = \
_ESPY_REC(_type, _func)
/**
* event_register - register a new spy
*
* @id: Spy ID
* @type: Event type to subscribe to
* @func: Function to call when the event is sent
* @ctx: Context to pass to the function
* @return 0 if OK, -ve on error
*/
int event_register(const char *id, enum event_t type, event_handler_t func,
void *ctx);
/** event_show_spy_list( - Show a list of event spies */
void event_show_spy_list(void);
#if CONFIG_IS_ENABLED(EVENT)
/**
* event_notify() - notify spies about an event
*
* It is possible to pass in union event_data here but that may not be
* convenient if the data is elsewhere, or is one of the members of the union.
* So this uses a void * for @data, with a separate @size.
*
* @type: Event type
* @data: Event data to be sent (e.g. union_event_data)
* @size: Size of data in bytes
* @return 0 if OK, -ve on error
*/
int event_notify(enum event_t type, void *data, int size);
/**
* event_notify_null() - notify spies about an event
*
* Data is NULL and the size is 0
*
* @type: Event type
* @return 0 if OK, -ve on error
*/
int event_notify_null(enum event_t type);
#else
static inline int event_notify(enum event_t type, void *data, int size)
{
return 0;
}
static inline int event_notify_null(enum event_t type)
{
return 0;
}
#endif
#if CONFIG_IS_ENABLED(EVENT_DYNAMIC)
/**
* event_uninit() - Clean up dynamic events
*
* This removes all dynamic event handlers
*/
int event_uninit(void);
/**
* event_uninit() - Set up dynamic events
*
* Init a list of dynamic event handlers, so that these can be added as
* needed
*/
int event_init(void);
#else
static inline int event_uninit(void)
{
return 0;
}
static inline int event_init(void)
{
return 0;
}
#endif
#endif
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