On Tue, Jul 17, 2012 at 4:38 AM, Benjamin Herrenschmidt
[off-list ref] wrote:
On Tue, 2012-07-17 at 18:03 +0800, Ram Pai wrote:
quoted
Lets say we passed that 'type' flag to size the minimum
alignment constraints for that b_res. And window_alignment(bus,
type) of your platform used that 'type' information to
determine whether to use the alignment constraints of 32-bit
window or 64-bit window.
However, later when the b_res is actually allocated a resource,
the pci_assign_resource() has no idea whether to allocate 32-bit
window resource or 64-bit window resource, because the 'type'
information is not captured anywhere in b_res.
You would basically have a disconnect between what is sized and
what is allocated. Unless offcourse you pass that 'type' to
the b_res->flags, which is currently not the case.
Right, we ideally would need the core to query the alignment once per
"apertures" it tries as a candidate to allocate a given resource... but
that's for later.
For now we can probably live with giving out the max of the minimum
alignment we support for M64 and our M32 segment size.
We already know the aperture we're proposing to allocate from (the
result of find_free_bus_resource()), don't we? What if we passed it
to pcibios_window_alignment() along with the struct pci_bus *, e.g.:
resource_size_t pcibios_window_alignment(struct pci_bus *bus, struct
resource *window)