Peter Korsgaard wrote:
"Michal" == Michal Simek <monstr@xxxxxxxxx> writes:
Hi,
>> That would make us spin in the interrupt for potentially quite a
>> while, E.G. until all data is transferred to the TX fifo.
Michal> yep. That's truth but shouldn't be a problem for standard
Michal> systems. Maybe worth to count how many times is tx fifo full on
Michal> standard systems.
But I still don't understand why you would want to burn CPU spinning
when you know the UART will be busy for a while. Leaving it alone until
it generates the TX fifo empty interrupt seems more logical to me.
I didn't know when tx fifo was full and then empty interrupt is
generated. I have added some debug things to driver and I am going to
look into.
I just changed return value and I have got correct output and then I
sent this email to check if is correct or not.
>> What kind of problem are you trying to fix in the first place? You
>> should get an interrupt when the TX fifo empties, which fill completely
>> fill up the fifo again and so on - That should work just fine even with
>> a low baud rate.
Michal> I am trying to solve the problem for xilinx mdm IP (compatible
Michal> with uartlite) where there are some missing characters on
Michal> serial console.
Strange. It's been a few years since I worked with Xilinx stuff and
never used microblaze, so I don't know anything about MDM.
It is console over jtag. Just different connection.
Michal> Maybe there is something wrong in different place but there are
Michal> definitely missing characters.
Michal> Just for the record: I also have to extend for loop in
Michal> ulite_console_wait_tx to get all chars for console.
Yeah, that loop should probably be time based (and perhaps calculated
from baud rate).
It is hard to say if you can find out any accurate number of loops which
is baud rate dependent.
Michal
--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
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