[U-Boot-Users] Memory Caching in Interrupt mode

[Wolfgang Denk]

In message <404DF1DA.2070609 at buckeye.ece.drexel.edu> you wrote:
> 
> I understand UBoot is not intended for use in interrupt modes, but I 

This is not exactly correct. Usually interrupts are  not  needed  and
used  (to  keep the code simple), but nothing prevents you from using
interrupts.  Even  the  first  examples  for  U-Boot  extensions  via
standalone programs included a timer interrupt demo.

> thought it does no harm in outputting some text on serial console 
> everytime an interrupt comes in, say a timer interrupt (every 1 sec). I 

Works fine here.

> am using BDI2000 to start debugging at 0x900. But my problem is that 
> since address translation is turned off while processing interrupts, I 
> am not able to write to the serial port address since processor caches 
> it and does not really push it out to the serial port. I am using 
> ns16550 driver and the serial port is at 0x60000000.
> 
> Whats the work around for this problem ?

Do not enable data cache.

> 2. Or shall i disable the data caches while processing interrupts ?

Don't enable DC at all.

Best regards,

Wolfgang Denk

-- 
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Schshschshchsch.
	-- The Gorn, "Arena", stardate 3046.2