Hi Pali, On Wed, 23 Feb 2022 at 06:34, Pali Rohár <[email protected]> wrote: > > On certain places it is required to flush output print buffers to ensure > that text strings were sent to console or serial devices. For example when > printing message that U-Boot is going to boot kernel or when U-Boot is > going to change baudrate of terminal device. > > Some console devices, like UART, have putc/puts functions which just put > characters into HW transmit queue and do not wait until all data are > transmitted. Doing some sensitive operations (like changing baudrate or > starting kernel which resets UART HW) cause that U-Boot messages are lost. > > Therefore introduce a new flush() function, implement it for all serial > devices via pending(false) callback and use this new flush() function on > sensitive places after which output device may go into reset state. > > This change fixes printing of U-Boot messages: > "## Starting application at ..." > "## Switch baudrate to ..." > > Signed-off-by: Pali Rohár <[email protected]> > --- > arch/sandbox/cpu/os.c | 5 +++ > boot/bootm_os.c | 1 + > cmd/boot.c | 1 + > cmd/elf.c | 2 ++ > cmd/load.c | 5 +++ > common/console.c | 56 ++++++++++++++++++++++++++++++++++ > common/stdio.c | 6 ++++ > drivers/serial/serial-uclass.c | 25 +++++++++++++++ > drivers/serial/serial.c | 1 + > include/_exports.h | 1 + > include/os.h | 8 +++++ > include/serial.h | 2 ++ > include/stdio.h | 7 +++++ > include/stdio_dev.h | 2 ++ > 14 files changed, 122 insertions(+)
There is a lot going on in this patch and I think it should be split into a small series, something like: - driver model changes (don't forget to update test/dm/serial.c) - stdio changes - sandbox changes - plumbing into certain commands You must not implement new features in the non-DM code as we are migrating away from that. So just implement it for driver model. Also, given the code-size impact I think this should have a Kconfig option. Regards, Simon
