[U-Boot-Users] Regarding Dcache Flush in MPC85xx

[Rafal Jaworowski]

Kumar Gala wrote:
>> We are using MPC8555 processor and uboot 1.1.4 both the uboot and  
>> linux
>> was up. Now we plan to port QNX, we are facing following issues.
>>
>> 1. Qnx is not jumping to the startup location.  After giving go  
>> command
>> control is still in the uboot only.
>>
>> 2.  When searching in the mailling list we came to know qnx required  
>> to
>> flush the Data Cache before disabling it in the uboot level
>> (common/cmd_bootelf.c line no:59)
>>
>> 3.  I checked other powerpc architecture like 7xx/74xx, 86xx and 4xx.
>> These architecture  has seperate cache.S file ( cpu/mpc86xx/ 
>> cache.S). That
>> file contains flush_data_cache function to flush the cache before
>> disabling it. But in the MPC85xx flushing the data cache was missing.
>>
>> 4. This is a bug in the 85xx uboot code. Is there any work arround for
>> this?
> 
> 1.1.4 is a fairly old u-boot at this point.  I believe we have  
> reworked the PPC cache ops and fixed the fact that 85xx was missing  
> flush_data_cache in the process.
> 

Not really, unfortunatelly: the 85xx still lacks flushing the d-cache before
disabling it. I was going to fix this by refactoring existing d-cache
disabling/flushing routines into a common code that would sit in the
lib_ppc/ppccache.S (as mostly exisiting implementations are just copy/paste of
the same thing) and have 85xx use it too, but didn't have time yet to clean it
up. If anyone is willing to do it sooner, I won't complain :)

Rafal