On 11/12/2013 08:05 AM, Thomas Petazzoni wrote:
Dear Grant Likely,
On Mon, 11 Nov 2013 15:50:50 +0000, Grant Likely wrote:
So the mbus would register an address xlate for its node that is
called instead of ranges parsing. For the example in my last message
the FPGA driver would register an xlate that made addresses relative
to its own BAR0 address.
There are already bus-specific transations available. Take a look at
struct of_bus in drivers/of/address.c
Hum, right, but unless I'm wrong the of_busses[] array of struct of_bus
is fixed in drivers/of/address.c, and as it is, there is no way for a
specific bus driver to provide its own struct of_bus.
That was exactly my understanding as well, and that's where I was
expecting some trickery to happen.
So that would need to be extended, right?
The other approach I was foreseeing was to implement a way of
dynamically updating the DT when the PCI subsystem enumerates the
devices and assigns memory areas (namely, I would expect the ranges
property to reflect that). But this would imply a standard way of
defining the ranges property (I would expect something like <bar#
start_addr length>, with an arguable number of cells). And I could
not find any such definition in the PCI bus binding document, so I'm
probably completely off-track here. Aren't I?
After all, we should expect a driver to behave (and expect) the same of
the DT, regardless of whether enumeration was performed by firmware or
by the OS itself. Or am I wrong on this too?
Thanks guys!
Gerlando
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