Add debug UART functions to permit ns16550 to provide an early debug UART.
Try to avoid using the stack so that this can be called from assembler before
a stack is set up (at least on ARM and PowerPC).
Signed-off-by: Simon Glass <sjg@chromium.org>
This came up in a discussion on the mailing list here:
https://patchwork.ozlabs.org/patch/384613/
My concerns at the time were:
- it doesn't need to be written in assembler
- it doesn't need to be ARM-specific
This patch provides a possible alternative. It works by allowing any serial
driver to export one init function and provide a putc() function. These
can be used to output debug data before the real serial driver is available.
This implementation does not depend on driver model, and it is possible for
it to operate without a stack on some architectures (e.g. PowerPC, ARM). It
provides the same features as the ARM-specific debug.S but with more UART
and architecture support.
Signed-off-by: Simon Glass <sjg@chromium.org>
Expand the help messages for each driver. Add missing Kconfig for I2C,
SPI flash and thermal.
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
This would be useful to start moving various config options.
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
