writing CCSR_BAR register for relocation?

Parav Pandit paravpandit at yahoo.com
Fri Jul 28 22:01:23 EST 2006


I have read the MPC8555 RF.
section 4.3.1.1 says that CCSRBAR is points to itself.

Checked by the md command in u-boot.
it shows the same results, FF70:0000.

It shows the FF704600 also at that address for all the
addresses it shows the same content as address.

If this is the case, how come the u-boot works on
serial port? It should show some other value for the
configured devices such as serial port at least.

or somethign is missing on my side...

Regards,
Parav Pandit


--- Parav Pandit <paravpandit at yahoo.com> wrote:

> Hi,
> 
> I am newbie to MPC8555, PowerPC family and u-boot.
> Please guide me.
> 
> 1. How can I read/write registers from the u-boot
> similar to md/mm command? Basically I want to
> read/write CCSR_BAR from the u-boot.
> 
> 2. How can I read/write CCSRBAR register value from
> my
> assembly program?
> mfspr.mtspr ??? what is the register name??
> 
> 3. By changing the default value of 0xFF70:0000 to
> 0xE000:0000 is sufficient to relocate the 1MB block
> or
> anything else is also required?
> 
> 4. I look at the u-boot code for tqm85xx, 8555cds,
> and
> 8555ads series of boards and it does something with
> TLB.
> I don't understand why it modifies the TLB registers
> whose purpose is only for the performance
> improvement?
> Or we can use the TLB for something else also?
> 
> Regards,
> Parav Pandit
> 
> 
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