dcr stuff.

Josh Boyer jwboyer at linux.vnet.ibm.com
Sat Mar 22 12:17:04 EST 2008


On Fri, 21 Mar 2008 12:05:40 -0700
"Stephen Neuendorffer" <stephen.neuendorffer at xilinx.com> wrote:

> 
> Is anybody working on the dcr infrastructure?
> 
> In particular, there seems to be inconsistency between what the kernel
> does and what ePAPR thinks it should.  The code in the kernel selects
> mmio or native access based on a Kconfig parameter and uses some device
> tree parameters to correctly configure the mmio access, whereas ePAPR
> doesn't seem to document all the device tree attributes (in particular,
> dcr-mmio-stride and dcr-mmio-range) and provides a dynamic binding for
> dcr-access-method...

Code can be fixed if needs be.  Keep in mind that ePAPR isn't publicly
available yet.

> Is there a plan here?  (In particular, in FPGA designs, its possible to
> have crazy things like multiple independent dcr busses, some using
> native access, some using mmio.  Or even if there is one bus, many of
> the existing non-linux drivers we have assume native or mmio access.
> I'd like to clean this up, obviously.. :)

Clean it up how?  I'd hate to add bloat to boards with native DCR
access just because a few require oddities.

If it ain't broke, don't fix it.

josh



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