Hi Wolfgang,
On Sat, Mar 10, 2012 at 12:24 PM, Wolfgang Denk wd@denx.de wrote:
Dear Simon Glass,
In message CAPnjgZ3wprPDNUbe0fGbsequXJgQ_bwzkDEu6FeuR-8GG1ndQQ@mail.gmail.com you wrote:
Also I do not understand why it would be needed at all. =A0We did not have such a requirement for any system before, so I feel you must be doing something wrong, or at least very exotic.
I put a fully explanation in the previous patch. Let me just add here
Explanations in some other patch are not available when someone reads the commit message ...
I did put a motivation in this patch at least:
Sometimes we want to be sure that the output FIFO has fully drained (e.g. because we are about to reset or the port or reset the board). Add a function for this.
that I see a 100ms delay in the reset code to allow serial output to flush, so there is at least in practice a need for this sort of thing.
Note that such a delay is hardware independent. You implement a special solution that works only for a minority of boards.
True, and we could just have the board panic function implement a delay, particularly if we move to the panic idea and away from putc().
For most archs the extra code will be removed by the linker.
Ok, granted.
You may also recall a discussion about a platform where the SPI flash and console uart were muxed, and we had to flush the console uart before switching to SPI. I feel that draining the FIFO could/should be a useful function.
You quote an example of highly specific hardware, which I would not hesitate to call a broken design. I do not really fancy adding code to common files for such exceptional situations.
It is certainly broken, yes.
Regards, Simon
Best regards,
Wolfgang Denk
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