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diff --git a/include/event.h b/include/event.h
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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
+
+#include <dm/ofnode_decl.h>
+#include <linux/types.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: This zero value is not used for events.
+	 */
+	EVT_NONE = 0,
+
+	/**
+	 * @EVT_TEST: This event is used in unit tests.
+	 */
+	EVT_TEST,
+
+	/**
+	 * @EVT_DM_POST_INIT_F:
+	 * This event is triggered after pre-relocation initialization of the
+	 * driver model. Its parameter is NULL.
+	 * A non-zero return code from the event handler let's the boot process
+	 * fail.
+	 */
+	EVT_DM_POST_INIT_F,
+
+	/**
+	 * @EVT_DM_POST_INIT_R:
+	 * This event is triggered after post-relocation initialization of the
+	 * driver model. Its parameter is NULL.
+	 * A non-zero return code from the event handler let's the boot process
+	 * fail.
+	 */
+	EVT_DM_POST_INIT_R,
+
+	/**
+	 * @EVT_DM_PRE_PROBE:
+	 * This event is triggered before probing a device. Its parameter is the
+	 * device to be probed.
+	 * A non-zero return code from the event handler lets the device not
+	 * being probed.
+	 */
+	EVT_DM_PRE_PROBE,
+
+	/**
+	 * @EVT_DM_POST_PROBE:
+	 * This event is triggered after probing a device. Its parameter is the
+	 * device that was probed.
+	 * A non-zero return code from the event handler leaves the device in
+	 * the unprobed state and therefore not usable.
+	 */
+	EVT_DM_POST_PROBE,
+
+	/**
+	 * @EVT_DM_PRE_REMOVE:
+	 * This event is triggered after removing a device. Its parameter is
+	 * the device to be removed.
+	 * A non-zero return code from the event handler stops the removal of
+	 * the device before any changes.
+	 */
+	EVT_DM_PRE_REMOVE,
+
+	/**
+	 * @EVT_DM_POST_REMOVE:
+	 * This event is triggered before removing a device. Its parameter is
+	 * the device that was removed.
+	 * A non-zero return code stops from the event handler the removal of
+	 * the device after all removal changes. The previous state is not
+	 * restored. All children will be gone and the device may not be
+	 * functional.
+	 */
+	EVT_DM_POST_REMOVE,
+
+	/**
+	 * @EVT_MISC_INIT_F:
+	 * This event is triggered during the initialization sequence before
+	 * relocation. Its parameter is NULL.
+	 * A non-zero return code from the event handler let's the boot process
+	 * fail.
+	 */
+	EVT_MISC_INIT_F,
+
+	/**
+	 * @EVT_FSP_INIT_F:
+	 * This event is triggered before relocation to set up Firmware Support
+	 * Package.
+	 * Where U-Boot relies on binary blobs to handle part of the system
+	 * init, this event can be used to set up the blobs. This is used on
+	 * some Intel platforms
+	 */
+	EVT_FSP_INIT_F,
+
+	/**
+	 * @EVT_SETTINGS_R:
+	 * This event is triggered post-relocation and before console init.
+	 * This gives an option to perform any platform-dependent setup, which
+	 * needs to take place before show_board_info() (e.g. readout of EEPROM
+	 * stored settings).
+	 */
+	EVT_SETTINGS_R,
+
+	/**
+	 * @EVT_LAST_STAGE_INIT:
+	 * This event is triggered just before jumping to the main loop.
+	 * Some boards need to perform initialisation immediately before control
+	 * is passed to the command-line interpreter (e.g. for init that depend
+	 * on later phases in the init sequence).
+	 *
+	 * Some parts can be only initialized if all others (like Interrupts)
+	 * are up and running (e.g. the PC-style ISA keyboard).
+	 */
+	EVT_LAST_STAGE_INIT,
+
+	/**
+	 * @EVT_FPGA_LOAD:
+	 * The FPGA load hook is called after loading an FPGA with a new binary.
+	 * Its parameter is of type struct event_fpga_load and contains
+	 * information about the loaded image.
+	 */
+	EVT_FPGA_LOAD,
+
+	/**
+	 * @EVT_FT_FIXUP:
+	 * This event is triggered during device-tree fix up after all
+	 * other device-tree fixups have been executed.
+	 * Its parameter is of type struct event_ft_fixup which contains
+	 * the address of the device-tree to fix up and the list of images to be
+	 * booted.
+	 * A non-zero return code from the event handler let's booting the
+	 * images fail.
+	 */
+	EVT_FT_FIXUP,
+
+	/**
+	 * @EVT_MAIN_LOOP:
+	 * This event is triggered immediately before calling main_loop() which
+	 * is the entry point of the command line. Its parameter is NULL.
+	 * A non-zero return value causes the boot to fail.
+	 */
+	EVT_MAIN_LOOP,
+
+	/**
+	 * @EVT_OF_LIVE_BUILT:
+	 * This event is triggered immediately after the live device tree has been
+	 * built. This allows for machine specific fixups to be done to the live tree
+	 * (like disabling known-unsupported devices) before it is used. This
+	 * event is only available if OF_LIVE is enabled and is only used after relocation.
+	 */
+	EVT_OF_LIVE_BUILT,
+
+	/**
+	 * @EVT_COUNT:
+	 * This constants holds the maximum event number + 1 and is used when
+	 * looping over all event classes.
+	 */
+	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_fpga_load - fpga load event
+	 *
+	 * @buf: The buffer that was loaded into the fpga
+	 * @bsize: The size of the buffer that was loaded into the fpga
+	 * @result: Result of the load operation
+	 */
+	struct event_fpga_load {
+		const void *buf;
+		size_t bsize;
+		int result;
+	} fpga_load;
+
+	/**
+	 * struct event_ft_fixup - FDT fixup before booting
+	 *
+	 * @tree: tree to update
+	 * @images: images which are being booted
+	 */
+	struct event_ft_fixup {
+		oftree tree;
+		struct bootm_headers *images;
+	} ft_fixup;
+
+	/**
+	 * struct event_of_live_built - livetree has been built
+	 *
+	 * @root: The root node of the live device tree
+	 */
+	struct event_of_live_built {
+		struct device_node *root;
+	} of_live_built;
+};
+
+/**
+ * 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;
+};
+
+/* Flags for event spy */
+enum evspy_flags {
+	EVSPYF_SIMPLE	= 1 << 0,
+};
+
+/** Function type for event handlers */
+typedef int (*event_handler_t)(void *ctx, struct event *event);
+
+/** Function type for simple event handlers */
+typedef int (*event_handler_simple_t)(void);
+
+/**
+ * struct evspy_info - information about an event spy
+ *
+ * @func: Function to call when the event is activated (must be first)
+ * @type: Event type
+ * @flags: Flags for this spy
+ * @id: Event id string
+ */
+struct evspy_info {
+	event_handler_t func;
+	u8 type;
+	u8 flags;
+#if CONFIG_IS_ENABLED(EVENT_DEBUG)
+	const char *id;
+#endif
+};
+
+/**
+ * struct evspy_info_simple - information about an event spy
+ *
+ * THis is the 'simple' record, the only difference being the handler function
+ *
+ * @func: Function to call when the event is activated (must be first)
+ * @type: Event type
+ * @flags: Flags for this spy
+ * @id: Event id string
+ */
+struct evspy_info_simple {
+	event_handler_simple_t func;
+	u8 type;
+	u8 flags;
+#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, 0, #_func, }
+#define _ESPY_REC_SIMPLE(_type, _func)  { _func, _type, EVSPYF_SIMPLE, #_func, }
+#else
+#define _ESPY_REC(_type, _func)   { _func, _type, }
+#define _ESPY_REC_SIMPLE(_type, _func)  { _func, _type, EVSPYF_SIMPLE }
+#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_FULL(EVT_MISC_INIT_F, sandbox_misc_init_f);
+ *
+ * where EVENT_SPY_FULL 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.
+ *
+ * Another issue has come up, only with clang: using 'static' makes it throw
+ * away the linker-list entry sometimes, e.g. with the EVT_FT_FIXUP entry in
+ * vbe_simple.c - so for now, make it global.
+ */
+#define EVENT_SPY_FULL(_type, _func) \
+	__used ll_entry_declare(struct evspy_info, _type ## _3_ ## _func, \
+		evspy_info) = _ESPY_REC(_type, _func)
+
+/* Simple spy with no function arguments */
+#define EVENT_SPY_SIMPLE(_type, _func) \
+	__used ll_entry_declare(struct evspy_info_simple, \
+		_type ## _3_ ## _func, \
+		evspy_info) = _ESPY_REC_SIMPLE(_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);
+
+/**
+ * event_type_name() - Get the name of an event type
+ *
+ * @type: Type to check
+ * Return: Name of event, or "(unknown)" if not known
+ */
+const char *event_type_name(enum event_t type);
+
+/**
+ * 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);
+
+#if CONFIG_IS_ENABLED(EVENT)
+/**
+ * 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_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_init() - 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