Commit graph

2 commits

Author SHA1 Message Date
Simon Glass
d0d7361462 debug_uart: Remove use of asmlinkage
This does not actually help any current arch. For x86 it makes it harder
to call (requires stack) and for ARM it has no effect. Drop it.

Signed-off-by: Simon Glass <sjg@chromium.org>
2015-07-21 17:39:21 -06:00
Simon Glass
2f964aa7b1 serial: Support an early UART for debugging
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>
2015-02-19 06:20:25 -07:00