On Thu, Dec 08, 2011 at 09:02:46PM +1030, Rusty Russell wrote:
> From: Michael S Tsirkin <mst@xxxxxxxxxx>
>
> Virtio drivers should map the part of the range they need, not necessarily
> all of it.
>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
I think that we should add a forcenocache flag.
This will let devices put the cap structure in
the prefetcheable BAR. That has an advantage that
it can be located anywhere in the 2^64 space,
while non-prefetcheable BARs are limited to lower 4G
for devices behind a PCI-to-PCI bridge.
> ---
> include/asm-generic/io.h | 4 ++++
> include/asm-generic/iomap.h | 11 +++++++++++
> lib/iomap.c | 41 ++++++++++++++++++++++++++++++++++++-----
> 3 files changed, 51 insertions(+), 5 deletions(-)
>
> diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
> index 9120887..3cf1787 100644
> --- a/include/asm-generic/io.h
> +++ b/include/asm-generic/io.h
> @@ -286,6 +286,10 @@ static inline void writesb(const void __iomem *addr, const void *buf, int len)
> /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
> struct pci_dev;
> extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
> +extern void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
> + unsigned offset,
> + unsigned long minlen,
> + unsigned long maxlen);
> static inline void pci_iounmap(struct pci_dev *dev, void __iomem *p)
> {
> }
> diff --git a/include/asm-generic/iomap.h b/include/asm-generic/iomap.h
> index 98dcd76..6f192d4 100644
> --- a/include/asm-generic/iomap.h
> +++ b/include/asm-generic/iomap.h
> @@ -70,8 +70,19 @@ extern void ioport_unmap(void __iomem *);
> /* Create a virtual mapping cookie for a PCI BAR (memory or IO) */
> struct pci_dev;
> extern void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max);
> +extern void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
> + unsigned offset,
> + unsigned long minlen,
> + unsigned long maxlen);
> extern void pci_iounmap(struct pci_dev *dev, void __iomem *);
> #else
> +static inline void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
> + unsigned offset,
> + unsigned long minlen,
> + unsigned long maxlen)
> +{
> + return NULL;
> +}
> struct pci_dev;
> static inline void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long max)
> {
> diff --git a/lib/iomap.c b/lib/iomap.c
> index 5dbcb4b..93ae915 100644
> --- a/lib/iomap.c
> +++ b/lib/iomap.c
> @@ -243,26 +243,37 @@ EXPORT_SYMBOL(ioport_unmap);
>
> #ifdef CONFIG_PCI
> /**
> - * pci_iomap - create a virtual mapping cookie for a PCI BAR
> + * pci_iomap_range - create a virtual mapping cookie for a PCI BAR
> * @dev: PCI device that owns the BAR
> * @bar: BAR number
> - * @maxlen: length of the memory to map
> + * @offset: map memory at the given offset in BAR
> + * @minlen: min length of the memory to map
> + * @maxlen: max length of the memory to map
> *
> * Using this function you will get a __iomem address to your device BAR.
> * You can access it using ioread*() and iowrite*(). These functions hide
> * the details if this is a MMIO or PIO address space and will just do what
> * you expect from them in the correct way.
> *
> + * @minlen specifies the minimum length to map. We check that BAR is
> + * large enough.
> * @maxlen specifies the maximum length to map. If you want to get access to
> - * the complete BAR without checking for its length first, pass %0 here.
> + * the complete BAR from offset to the end, pass %0 here.
> * */
> -void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
> +void __iomem *pci_iomap_range(struct pci_dev *dev, int bar,
> + unsigned offset,
> + unsigned long minlen,
> + unsigned long maxlen)
> {
> resource_size_t start = pci_resource_start(dev, bar);
> resource_size_t len = pci_resource_len(dev, bar);
> unsigned long flags = pci_resource_flags(dev, bar);
>
> - if (!len || !start)
> + if (len <= offset || !start)
> + return NULL;
> + len -= offset;
> + start += offset;
> + if (len < minlen)
> return NULL;
> if (maxlen && len > maxlen)
> len = maxlen;
> @@ -277,10 +288,30 @@ void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
> return NULL;
> }
>
> +/**
> + * pci_iomap - create a virtual mapping cookie for a PCI BAR
> + * @dev: PCI device that owns the BAR
> + * @bar: BAR number
> + * @maxlen: length of the memory to map
> + *
> + * Using this function you will get a __iomem address to your device BAR.
> + * You can access it using ioread*() and iowrite*(). These functions hide
> + * the details if this is a MMIO or PIO address space and will just do what
> + * you expect from them in the correct way.
> + *
> + * @maxlen specifies the maximum length to map. If you want to get access to
> + * the complete BAR without checking for its length first, pass %0 here.
> + * */
> +void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
> +{
> + return pci_iomap_range(dev, bar, 0, 0, maxlen);
> +}
> +
> void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
> {
> IO_COND(addr, /* nothing */, iounmap(addr));
> }
> EXPORT_SYMBOL(pci_iomap);
> +EXPORT_SYMBOL(pci_iomap_range);
> EXPORT_SYMBOL(pci_iounmap);
> #endif /* CONFIG_PCI */
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