Re: ioremap() and port of linux to MPC7400 based SBC (VME board)

Re: ioremap() and port of linux to MPC7400 based SBC (VME board)

[Heinz-Jürgen Oertel]

him wrote:

> I have run into a problem I am having a hard time figuring out.
> 
> I have an MPC7400 SBC (PCI bus based) that has a device X residing
> at the following locations in memory:
> 
> 0x1860 0000 - 0x186f ffff     device control register space
> 0xb000 0000 - 0xbfff ffff     device memory space
> 
> Now assume for a moment that NOTHING special needs to be done to
> access either space once the system has booted and bus enumerator
> have set things up.
> 
> ioremap() of the first physical address returns a VALID virtual
> address  ... that I can read and write to. It works as expected
> because there are signature values at various offsets in the control
> register space.
> The virtual address returned is EQUAL to the physical address
> 
> ioremap() of the second physical address also returns what appears to
> be a VALID virtual address although WRITES go nowhere and READS return
> all ff's.
> The virtual address returned is 0xc100 0000
> 
> 
> 
> Now my question ... I have the source for the port. Where should I focus
> my efforts in trying to figure this out?
> 
> I have read the device drivers book and certain that I am following
> the rules.
> 
> I should also mention that there is an IO controller seperate from the
> MPC7400 that I use to verify that the device X control and memory exist
> in THAT physical range.
> 
> If Only I can access them through ioremap()
> 
> Thanks

No idea up to now, but what kernel, what linux? is it VM linux or uClinux?

Heinz
-- 

with best regards / mit freundlichen Grüßen

   Heinz-Jürgen Oertel
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