Benjamin Herrenschmidt wrote:
pci_enable(info on what to enable)
so that drivers can specify ahead of time "don't enable PIO, only MMIO",
"don't enable MMIO, only PIO", "don't use MSI", etc. and add a
pci_disable() to undo all of that.
The more we add singleton functions like pci_enable_msi(),
pci_set_master(), etc. the more I wish for a single function that
handled all those details at one atomic point. There is a lot of
standard patterns that are hand-coded into every PCI driver's probe
functions.
Agreed, with the proper arch hook to deal with arch brokenness of
course.
That could be a bitmap. What I'm not 100% confident at this point is
wether we want a bit per BAR or an "IO" bit and an "MMIO" bit. I think
I'd rather go for the first one.
A bitmap is what I would start with. But I would implement it as
struct pci_enable_info {
unsigned long flags;
};
because I guarantee we'll want more flexibility as time goes on.
Honestly I can think of situations where one driver would want a bit per
BAR, and many others would just need a single MMIO bit. Don't forget
legacy decoding too: with -only- a bit per BAR, the driver cannot tell
the PCI layer that disabling IO means disabling a legacy ISA region
that's not listed in the PCI BARs.
Jeff
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