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.
Enabling events uses a little over 200 bytes of extra code space, on 32-bit machines, a one-off cost.
Simon Glass (12): Makefile: Keep symbols in u-boot-init with LTO sandbox: start: Sort the header files binman: Expand elf support a little event: Add basic support for events event: Add a simple test event: Set up the event system on start-up event: Add events for device probe/remove event: Convert misc_init_f() to use events event: Convert arch_cpu_init_dm() to use events event: Add a command event: Add a script to decode the event-spy list event: Add documentation
MAINTAINERS | 10 ++ Makefile | 2 +- arch/Kconfig | 3 + arch/arm/Kconfig | 3 + arch/arm/include/asm/omap_common.h | 2 + arch/arm/mach-imx/imx8m/soc.c | 4 +- arch/arm/mach-imx/imx8ulp/soc.c | 4 +- arch/arm/mach-omap2/am33xx/board.c | 10 +- arch/arm/mach-omap2/hwinit-common.c | 5 +- arch/mips/Kconfig | 1 + arch/mips/mach-pic32/cpu.c | 4 +- arch/nios2/cpu/cpu.c | 4 +- arch/riscv/cpu/cpu.c | 5 +- arch/riscv/include/asm/system.h | 5 + arch/riscv/lib/spl.c | 3 +- arch/sandbox/cpu/start.c | 8 +- arch/x86/cpu/baytrail/cpu.c | 4 +- arch/x86/cpu/broadwell/cpu.c | 4 +- arch/x86/cpu/ivybridge/cpu.c | 4 +- arch/x86/cpu/quark/quark.c | 4 +- arch/x86/include/asm/fsp2/fsp_api.h | 8 ++ arch/x86/lib/fsp2/fsp_init.c | 4 +- arch/x86/lib/spl.c | 12 -- arch/x86/lib/tpl.c | 10 -- board/google/chromebook_coral/coral.c | 6 +- board/keymile/kmcent2/kmcent2.c | 5 +- cmd/Kconfig | 8 ++ cmd/Makefile | 1 + cmd/event.c | 27 ++++ common/Kconfig | 37 ++++- common/Makefile | 2 + common/board_f.c | 13 +- common/board_r.c | 1 + common/event.c | 196 ++++++++++++++++++++++++++ common/log.c | 1 + configs/chromebook_coral_defconfig | 1 + configs/galileo_defconfig | 1 + configs/kmcent2_defconfig | 2 +- configs/sandbox64_defconfig | 1 - configs/sandbox_defconfig | 1 - configs/sandbox_flattree_defconfig | 1 - configs/sandbox_spl_defconfig | 1 - configs/tools-only_defconfig | 1 - doc/develop/event.rst | 100 +++++++++++++ doc/develop/index.rst | 1 + doc/usage/event.rst | 49 +++++++ doc/usage/index.rst | 1 + drivers/core/Kconfig | 10 ++ drivers/core/device-remove.c | 8 ++ drivers/core/device.c | 9 ++ drivers/core/root.c | 5 + include/asm-generic/global_data.h | 13 ++ include/dm/device-internal.h | 10 ++ include/event.h | 182 ++++++++++++++++++++++++ include/event_internal.h | 35 +++++ include/init.h | 12 -- include/log.h | 2 + scripts/event_dump.py | 117 +++++++++++++++ test/common/Makefile | 1 + test/common/event.c | 85 +++++++++++ test/py/tests/test_event_dump.py | 19 +++ test/test-main.c | 4 + tools/binman/elf.py | 58 +++++++- 63 files changed, 1067 insertions(+), 83 deletions(-) create mode 100644 cmd/event.c create mode 100644 common/event.c create mode 100644 doc/develop/event.rst create mode 100644 doc/usage/event.rst create mode 100644 include/event.h create mode 100644 include/event_internal.h create mode 100755 scripts/event_dump.py create mode 100644 test/common/event.c create mode 100644 test/py/tests/test_event_dump.py