On Thu, Aug 13, 2015 at 10:11:09PM +0800, Wei Yang wrote: >At the moment 64bit-prefetchable window can be maximum 64GB, which is >currently got from device tree. This means that in shared mode the maximum >supported VF BAR size is 64GB/256=256MB. While this size could exhaust the >whole 64bit-prefetchable window. This is a design decision to set a >boundary to 64MB of the VF BAR size. Since VF BAR size with 64MB would >occupy a quarter of the 64bit-prefetchable window, this is affordable. > >This patch replaces magic limit of 64MB with (m64_segsize >> 1) and adds >comment to explain the reason for it. > >Signed-off-by: Wei Yang <[email protected]>
Reviewed-by: Gavin Shan <[email protected]> >--- > arch/powerpc/platforms/powernv/pci-ioda.c | 22 +++++++++++++++++----- > 1 file changed, 17 insertions(+), 5 deletions(-) > >diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c >b/arch/powerpc/platforms/powernv/pci-ioda.c >index 4da0f50..3e8c0b4 100644 >--- a/arch/powerpc/platforms/powernv/pci-ioda.c >+++ b/arch/powerpc/platforms/powernv/pci-ioda.c >@@ -2688,7 +2688,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct >pci_dev *pdev) > struct pnv_phb *phb; > struct resource *res; > int i; >- resource_size_t size; >+ resource_size_t size, gate; > struct pci_dn *pdn; > int mul, total_vfs; > >@@ -2704,6 +2704,17 @@ static void pnv_pci_ioda_fixup_iov_resources(struct >pci_dev *pdev) > > total_vfs = pci_sriov_get_totalvfs(pdev); > mul = phb->ioda.total_pe; >+ /* >+ * If bigger than or equal to half of M64 segment size, just round up >+ * power of two. >+ * >+ * Generally, one M64 BAR maps one IOV BAR. To avoid conflict with >+ * other devices, IOV BAR size is expanded to be (total_pe * >+ * VF_BAR_size). When VF_BAR_size is half of M64 segment size , the >+ * expanded size would equal to half of the whole M64 Space size, >+ * which will exhaust the M64 Space and limit the system flexibility. >+ */ s/M64 Space/M64 space >+ gate = phb->ioda.m64_segsize >> 1; > > for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) { > res = &pdev->resource[i + PCI_IOV_RESOURCES]; >@@ -2718,10 +2729,11 @@ static void pnv_pci_ioda_fixup_iov_resources(struct >pci_dev *pdev) > > size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES); > >- /* bigger than 64M */ >- if (size > (1 << 26)) { >- dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size >is bigger than 64M, roundup power2\n", >- i, res); >+ /* bigger than or equal to gate */ >+ if (size >= gate) { >+ dev_info(&pdev->dev, "PowerNV: VF BAR%d: %pR IOV size " >+ "is bigger than %lld, roundup power2\n", >+ i, res, gate); > mul = roundup_pow_of_two(total_vfs); > pdn->m64_single_mode = true; > break; >-- >1.7.9.5 > _______________________________________________ Linuxppc-dev mailing list [email protected] https://lists.ozlabs.org/listinfo/linuxppc-dev
