On Wed, 14 Jan 2015, Michael S. Tsirkin wrote:
> Virtio drivers should map the part of the range they need, not
> necessarily all of it.
> To this end, support mapping ranges within BAR on s390.
> Since multiple ranges can now be mapped within a BAR, we keep track of
> the number of mappings created, and only clear out the mapping for a BAR
> when this number reaches 0.
>
> Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx
> Tested-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
>
> Heiko, Martin, can you please ack merging this through the virtio tree?
> This was lightly tested by Sebastian Ott.
>
> arch/s390/include/asm/pci_io.h | 1 +
> arch/s390/pci/pci.c | 34 +++++++++++++++++++++++++++-------
> 2 files changed, 28 insertions(+), 7 deletions(-)
>
> diff --git a/arch/s390/include/asm/pci_io.h b/arch/s390/include/asm/pci_io.h
> index f664e96..1a9a98d 100644
> --- a/arch/s390/include/asm/pci_io.h
> +++ b/arch/s390/include/asm/pci_io.h
> @@ -16,6 +16,7 @@
> struct zpci_iomap_entry {
> u32 fh;
> u8 bar;
> + u16 count;
> };
>
> extern struct zpci_iomap_entry *zpci_iomap_start;
> diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
> index 3290f11..753a567 100644
> --- a/arch/s390/pci/pci.c
> +++ b/arch/s390/pci/pci.c
> @@ -259,7 +259,10 @@ void __iowrite64_copy(void __iomem *to, const void *from, size_t count)
> }
>
> /* Create a virtual mapping cookie for a PCI BAR */
> -void __iomem *pci_iomap(struct pci_dev *pdev, int bar, unsigned long max)
> +void __iomem *pci_iomap_range(struct pci_dev *pdev,
> + int bar,
> + unsigned long offset,
> + unsigned long max)
> {
> struct zpci_dev *zdev = get_zdev(pdev);
> u64 addr;
> @@ -270,14 +273,27 @@ void __iomem *pci_iomap(struct pci_dev *pdev, int bar, unsigned long max)
>
> idx = zdev->bars[bar].map_idx;
> spin_lock(&zpci_iomap_lock);
> - zpci_iomap_start[idx].fh = zdev->fh;
> - zpci_iomap_start[idx].bar = bar;
> + if (zpci_iomap_start[idx].count++) {
> + BUG_ON(zpci_iomap_start[idx].fh != zdev->fh ||
> + zpci_iomap_start[idx].bar != bar);
> + } else {
> + zpci_iomap_start[idx].fh = zdev->fh;
> + zpci_iomap_start[idx].bar = bar;
> + }
> + /* Detect overrun */
> + BUG_ON(!zpci_iomap_start[idx].count);
> spin_unlock(&zpci_iomap_lock);
>
> addr = ZPCI_IOMAP_ADDR_BASE | ((u64) idx << 48);
> - return (void __iomem *) addr;
> + return (void __iomem *) addr + offset;
> }
> -EXPORT_SYMBOL_GPL(pci_iomap);
> +EXPORT_SYMBOL_GPL(pci_iomap_range);
> +
> +void __iomem *pci_iomap(struct pci_dev *dev, int bar, unsigned long maxlen)
> +{
> + return pci_iomap_range(dev, bar, 0, maxlen);
> +}
> +EXPORT_SYMBOL(pci_iomap);
As discussed earlier, could you please leave that as EXPORT_SYMBOL_GPL.
If there's a reason to have these interfaces as EXPORT_SYMBOL, we could
change all of them in an extra patch.
With this change integrated you can add
Acked-by: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Regards,
Sebastian
>
> void pci_iounmap(struct pci_dev *pdev, void __iomem *addr)
> {
> @@ -285,8 +301,12 @@ void pci_iounmap(struct pci_dev *pdev, void __iomem *addr)
>
> idx = (((__force u64) addr) & ~ZPCI_IOMAP_ADDR_BASE) >> 48;
> spin_lock(&zpci_iomap_lock);
> - zpci_iomap_start[idx].fh = 0;
> - zpci_iomap_start[idx].bar = 0;
> + /* Detect underrun */
> + BUG_ON(!zpci_iomap_start[idx].count);
> + if (!--zpci_iomap_start[idx].count) {
> + zpci_iomap_start[idx].fh = 0;
> + zpci_iomap_start[idx].bar = 0;
> + }
> spin_unlock(&zpci_iomap_lock);
> }
> EXPORT_SYMBOL_GPL(pci_iounmap);
> --
> MST
>
>
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