This series introduces threads and uses them to improve the performance of the USB bus scanning code and to implement background jobs in the shell via two new commands: 'spawn' and 'wait'.
The threading framework is called 'uthread' and is inspired from the barebox threads [1]. setjmp() and longjmp() are used to save and restore contexts, as well as a non-standard extension called initjmp(). This new function is added in several patches, one for each architecture that supports HAVE_SETJMP. A new symbol is defined: HAVE_INITJMP. Two tests, one for initjmp() and one for the uthread scheduling, are added to the lib suite. NOTE: the SANDBOX version of initjmp() appears to have problems and needs to be worked on. [1] https://github.com/barebox/barebox/blob/master/common/bthread.c After introducing threads and making schedule() and udelay() a thread re-scheduling point, the USB stack initialization is modified to benefit from concurrency when UTHREAD is enabled, where uthreads are used in usb_init() to initialize and scan multiple busses at the same time. The code was tested on arm64 and arm QEMU with 4 simulated XHCI buses and some devices. On this platform the USB scan takes 2.2 s instead of 5.6 s. Tested on i.MX93 EVK with two USB hubs, one ethernet adapter and one webcam on each, "usb start" takes 2.4 s instead of 4.6 s. Finally, the spawn and wait commands are introduced, allowing the use of threads from the shell. Tested on the i.MX93 EVK with a spinning HDD connected to USB1 and the network connected to ENET1. The USB plus DHCP init sequence "spawn usb start; spawn dhcp; wait" takes 4.5 seconds instead of 8 seconds for "usb start; dhcp". Changes in v2: - Rewrite the cover letter, do not mention the older coroutines series - Rebased onto next - UTHREAD_STACK_SIZE is set to 32768 (32 KiB) instead of 32178 - Remove uthread_free_all() and let threads be freed as they terminate by uthread_schedule() - Add function descriptions - Add documentation (doc/develop/uthread.rst) - Explain initjmp() in the description of "arch: introduce symbol HAVE_INITJMP". - Add thread groups (uthread_grp_new_id() and uthread_grp_done()) - Add the spawn and wait commands Jerome Forissier (14): arch: introduce symbol HAVE_INITJMP arm: add initjmp() riscv: add initjmp() sandbox: add initjmp() test: lib: add initjmp() test uthread: add cooperative multi-tasking interface cyclic: invoke uthread_schedule() from schedule() lib: time: hook uthread_schedule() into udelay() doc: develop: add documentation for uthreads test: lib: add uthread test dm: usb: move bus initialization into new static function usb_init_bus() dm: usb: initialize and scan multiple buses simultaneously with uthread cmd: add spawn and wait commands test: dm: add test for spawn and wait commands arch/Kconfig | 8 ++ arch/arm/include/asm/setjmp.h | 1 + arch/arm/lib/setjmp.S | 11 ++ arch/arm/lib/setjmp_aarch64.S | 9 ++ arch/riscv/include/asm/setjmp.h | 1 + arch/riscv/lib/setjmp.S | 10 ++ arch/sandbox/cpu/Makefile | 11 +- arch/sandbox/cpu/initjmp.c | 172 +++++++++++++++++++++++++++++ arch/sandbox/include/asm/setjmp.h | 5 + cmd/Kconfig | 17 +++ cmd/Makefile | 2 + cmd/spawn.c | 176 +++++++++++++++++++++++++++++ common/console.c | 2 + common/cyclic.c | 3 + doc/develop/index.rst | 1 + doc/develop/uthread.rst | 136 +++++++++++++++++++++++ drivers/usb/host/usb-uclass.c | 168 +++++++++++++++++++--------- include/u-boot/schedule.h | 3 + include/uthread.h | 44 ++++++++ lib/Kconfig | 21 ++++ lib/Makefile | 2 + lib/time.c | 10 +- lib/uthread.c | 178 ++++++++++++++++++++++++++++++ test/boot/bootdev.c | 14 +-- test/boot/bootflow.c | 2 +- test/cmd/Makefile | 1 + test/cmd/spawn.c | 33 ++++++ test/lib/Makefile | 2 + test/lib/initjmp.c | 72 ++++++++++++ test/lib/uthread.c | 68 ++++++++++++ 30 files changed, 1122 insertions(+), 61 deletions(-) create mode 100644 arch/sandbox/cpu/initjmp.c create mode 100644 cmd/spawn.c create mode 100644 doc/develop/uthread.rst create mode 100644 include/uthread.h create mode 100644 lib/uthread.c create mode 100644 test/cmd/spawn.c create mode 100644 test/lib/initjmp.c create mode 100644 test/lib/uthread.c -- 2.43.0
