Hi Wilson, On Fri, Aug 25, 2017 at 11:29 AM, Wilson Lee <[email protected]> wrote: > From: Keng Soon Cheah <[email protected]> > > Some device the serial console's initialization cannot run early during > the boot process. Hence, nulldev serial device is helpful on that > situation. > > For example, if the serial module was implemented in FPGA. Serial > initialization is prohibited to run until the FPGA was programmed. >
I still don't fully understand this. Shouldn't the FPGA serial driver has some sort of register bits that determine if it's ready? And if not ready, the FPGA serial driver can do nothing like your null serial driver does? > This commit is to adding nulldev serial driver. This will allows the > default console to be specified as a nulldev. > > Signed-off-by: Joe Hershberger <[email protected]> > Signed-off-by: Keng Soon Cheah <[email protected]> > Cc: Chen Yee Chew <[email protected]> > --- > drivers/serial/Kconfig | 7 ++++++ > drivers/serial/Makefile | 1 + > drivers/serial/serial_nulldev.c | 48 > +++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 56 insertions(+) > create mode 100644 drivers/serial/serial_nulldev.c > [snip] Regards, Bin _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
