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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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