Messages in this thread | | | Date | Thu, 15 Aug 2002 10:58:17 -0500 (CDT) | From | Kai Germaschewski <> | Subject | RE: [patch] PCI Cleanup |
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On Wed, 14 Aug 2002, Grover, Andrew wrote:
> ACPI needs access to PCI config space, and it doesn't have a struct pci_dev > to pass to access functions. It doesn't look like your patch exposes an > interface that 1) doesn't require a pci_dev and 2) abstracts the PCI config > access method, does it?
I think drivers/hotplug/pci_hotplug_util.c implements something like you need, pci_read_config_byte_nodev().
Of course that's currently only available for PCI hotplug, and for all I can see the concept is somewhat messed up, but maybe that's an opportunity to clean things up?
Currently, pci_read_config_byte_nodev() will construct a fake struct pci_dev, and then use the normal pci_read_config_byte(). I think it makes more sense to actually do things the other way around.
For reading/writing config space, we need to know (dev, fn), and need the access method (struct pci_ops), which is a property of the bridge plus possibly some private data (the arch's sysdata). So the member
struct pci_ops *ops;
of struct pci_dev is actually not necessary, it will always be pdev->ops == pdev->bus->ops AFAICS.
So we could instead have
pci_bus_read_config_byte(struct pci_bus *bus, u8 dev, u8 fn, ...)
and for common use
static inline pci_read_config_byte(struct pci_dev, *pdev, ...) { return pci_bus_read_config_byte(pdev->bus, PCI_SLOT(pdev->devfn), PCI_FUNC(pdev->devfn)); }
The PCI hotplug controllers / ACPI could then use the pci_bus_* variants, when they don't have a struct pci_dev available. They would need at least the root bridge's struct pci_bus, though.
--Kai
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