[U-Boot] [PATCH v4] Add board_pre_console_putc to deal with early console output

[Stefano Babic <sbabic@denx.de>]

On 19/10/2011 01:43, Simon Glass wrote:
> This patch adds support for console output before the console is inited.
> The main purpose of this is to deal with a very early panic() which would
> otherwise cause a silent hang.
> 
> A new board_pre_console_putc() function is added to the board API. If
> provided by the board it will be called in the event of console output
> before the console is ready. This function should turn on all UARTs and
> spray the character out if it possibly can.
> 
> The feature is controlled by a new CONFIG_PRE_CONSOLE_PUTC option.
> 
> Signed-off-by: Simon Glass <sjg@chromium.org>
> ---

Hi Simon,


> Changes in v2:
> - Made this feature conditional on CONFIG_PRE_CONSOLE_PANIC
> 
> Changes in v3:
> - Rewrite this to be independent of panic()
> - Rename feature to CONFIG_PRE_CONSOLE_PUTC
> 
> Changes in v4:
> - Remove weak function, so we get a link error if it is undefined by the board

maybe I have not understood the real goal of this patch. We have already
a CONFIG_PRE_CONSOLE_BUFFER, that tries to store the output when the
console is not avalable - and can be retrieved with a JTAG debugger.

Your patch adds a way to call some serial setup in board code, but it is
not said that works or can work for all / most boards. Compared to the
usage of the circular buffer, it is not so general - am I missing
something ?

Best regards,
Stefano Babic

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