Hi,
On 11/12/2013 09:16 AM, Thomas Petazzoni wrote:
Dear Gerlando Falauto,
On Tue, 12 Nov 2013 09:11:33 +0100, Gerlando Falauto wrote:
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?
Well, in the context of the mvebu platforms (including Kirkwood), the
problem is not so much the ranges in the pcie-controller node, but the
ranges in the main soc { ... } node which encloses the description of
the MBus. It is those ranges that need to be updated when a new window
is created, or a window is removed. So the problem is not PCI related,
but MBus related in this case, no?
I was actually referring to ranges within the PCI *device* (~leaf node).
So not thinking about mvebu, but rather about general PCI devices.
I see drivers/of/address.c implements some:
extern const __be32 *of_get_pci_address(struct device_node *dev, int bar_no,
u64 *size, unsigned int *flags);
extern int of_pci_address_to_resource(struct device_node *dev, int bar,
struct resource *r);
Which are not hooked to any ranges (of_bus) mechanisms nor any DT-aware
PCI device driver and that's where I got completely lost.
But I'm probably looking at it from a wrong perspective.
Thanks,
Gerlando
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