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    SubjectRe: [PATCH 3/3] PCI: Add pci_read_base() API
    On Mon, Jul 28, 2008 at 01:39:01PM -0400, Matthew Wilcox wrote:
    > Some devices have a BAR at a non-standard address. The pci_read_base()
    > API allows us to probe these BARs and fill in a resource for it as if
    > they were standard BARs.

    Willy,
    Can you add a comment to the code listing the offending device?
    That way we know how to test next time this code changes.

    thanks,
    grant

    >
    > Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
    > ---
    > drivers/pci/probe.c | 47 ++++++++++++++++++++++++++++++++++++++++-------
    > include/linux/pci.h | 10 ++++++++++
    > 2 files changed, 50 insertions(+), 7 deletions(-)
    >
    > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
    > index 2036300..a977d07 100644
    > --- a/drivers/pci/probe.c
    > +++ b/drivers/pci/probe.c
    > @@ -181,13 +181,6 @@ static u64 pci_size(u64 base, u64 maxbase, u64 mask)
    > return size;
    > }
    >
    > -enum pci_bar_type {
    > - pci_bar_unknown, /* Standard PCI BAR probe */
    > - pci_bar_io, /* An io port BAR */
    > - pci_bar_mem32, /* A 32-bit memory BAR */
    > - pci_bar_mem64, /* A 64-bit memory BAR */
    > -};
    > -
    > static inline enum pci_bar_type decode_bar(struct resource *res, u32 bar)
    > {
    > if ((bar & PCI_BASE_ADDRESS_SPACE) == PCI_BASE_ADDRESS_SPACE_IO) {
    > @@ -300,6 +293,46 @@ static int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
    > goto out;
    > }
    >
    > +/**
    > + * pci_read_base - Read a BAR from a specified location
    > + * @dev: The PCI device to read
    > + * @type: The type of BAR to read
    > + * @res: A struct resource to be filled in
    > + * @reg: The address in PCI config space to read the BAR from.
    > + *
    > + * Some devices have BARs in unusual places. This function lets a driver ask
    > + * the PCI subsystem to read it and place it in the resource tree. If it is
    > + * like a ROM BAR with an enable in bit 0, the caller should specify a @type
    > + * of io, mem32 or mem64. If it's like a normal BAR with memory type in the
    > + * low bits, specify unknown, even if the caller knows what kind of BAR it is.
    > + *
    > + * Returns -ENXIO if the BAR was not successfully read. If the BAR is read,
    > + * but no suitable parent resource can be found for the BAR, this function
    > + * returns -ENODEV. If the resource cannot be inserted into the resource tree,
    > + * it will return -EBUSY. Note that the resource is still 'live' for these
    > + * last two cases; the caller should set res->flags to 0 if this is not wanted.
    > + */
    > +int pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
    > + struct resource *res, unsigned int reg)
    > +{
    > + struct pci_bus_region region;
    > + struct resource *parent;
    > +
    > + __pci_read_base(dev, type, res, reg);
    > + if (!res->flags)
    > + return -ENXIO;
    > +
    > + region.start = res->start;
    > + region.end = res->end;
    > + pcibios_bus_to_resource(dev, res, &region);
    > +
    > + parent = pci_find_parent_resource(dev, res);
    > + if (!parent)
    > + return -ENODEV;
    > + return request_resource(parent, res);
    > +}
    > +EXPORT_SYMBOL_GPL(pci_read_base);
    > +
    > static void pci_read_bases(struct pci_dev *dev, unsigned int howmany, int rom)
    > {
    > unsigned int pos, reg;
    > diff --git a/include/linux/pci.h b/include/linux/pci.h
    > index a6a088e..f6ad5e8 100644
    > --- a/include/linux/pci.h
    > +++ b/include/linux/pci.h
    > @@ -310,6 +310,16 @@ struct pci_bus {
    > #define pci_bus_b(n) list_entry(n, struct pci_bus, node)
    > #define to_pci_bus(n) container_of(n, struct pci_bus, dev)
    >
    > +enum pci_bar_type {
    > + pci_bar_unknown, /* Standard PCI BAR probe */
    > + pci_bar_io, /* An io port BAR */
    > + pci_bar_mem32, /* A 32-bit memory BAR */
    > + pci_bar_mem64, /* A 64-bit memory BAR */
    > +};
    > +
    > +int pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
    > + struct resource *res, unsigned int reg);
    > +
    > /*
    > * Error values that may be returned by PCI functions.
    > */
    > --
    > 1.5.5.4
    > --
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    > More majordomo info at http://vger.kernel.org/majordomo-info.html


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