powerpc/powernv: Reserve additional space for IOV BAR, with m64_per_iov supported

M64 aperture size is limited on PHB3.  When the IOV BAR is too big, this
will exceed the limitation and failed to be assigned.

Introduce a different mechanism based on the IOV BAR size:

  - if IOV BAR size is smaller than 64MB, expand to total_pe
  - if IOV BAR size is bigger than 64MB, roundup power2

[bhelgaas: make dev_printk() output more consistent, use PCI_SRIOV_NUM_BARS]
Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

arch/powerpc/include/asm/pci-bridge.h

@@ -182,6 +182,8 @@ struct pci_dn {
 	u16     vfs_expanded;		/* number of VFs IOV BAR expanded */
 	u16     num_vfs;		/* number of VFs enabled*/
 	int     offset;			/* PE# for the first VF PE */
+#define M64_PER_IOV 4
+	int     m64_per_iov;
 #define IODA_INVALID_M64        (-1)
 	int     m64_wins[PCI_SRIOV_NUM_BARS];
 #endif /* CONFIG_PCI_IOV */

arch/powerpc/platforms/powernv/pci-ioda.c

@@ -2250,6 +2250,7 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
 	int i;
 	resource_size_t size;
 	struct pci_dn *pdn;
+	int mul, total_vfs;
 
 	if (!pdev->is_physfn || pdev->is_added)
 		return;
@@ -2260,6 +2261,32 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
 	pdn = pci_get_pdn(pdev);
 	pdn->vfs_expanded = 0;
 
+	total_vfs = pci_sriov_get_totalvfs(pdev);
+	pdn->m64_per_iov = 1;
+	mul = phb->ioda.total_pe;
+
+	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
+		res = &pdev->resource[i + PCI_IOV_RESOURCES];
+		if (!res->flags || res->parent)
+			continue;
+		if (!pnv_pci_is_mem_pref_64(res->flags)) {
+			dev_warn(&pdev->dev, " non M64 VF BAR%d: %pR\n",
+				 i, res);
+			continue;
+		}
+
+		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);
+			pdn->m64_per_iov = M64_PER_IOV;
+			mul = roundup_pow_of_two(total_vfs);
+			break;
+		}
+	}
+
 	for (i = 0; i < PCI_SRIOV_NUM_BARS; i++) {
 		res = &pdev->resource[i + PCI_IOV_RESOURCES];
 		if (!res->flags || res->parent)
@@ -2272,12 +2299,12 @@ static void pnv_pci_ioda_fixup_iov_resources(struct pci_dev *pdev)
 
 		dev_dbg(&pdev->dev, " Fixing VF BAR%d: %pR to\n", i, res);
 		size = pci_iov_resource_size(pdev, i + PCI_IOV_RESOURCES);
-		res->end = res->start + size * phb->ioda.total_pe - 1;
+		res->end = res->start + size * mul - 1;
 		dev_dbg(&pdev->dev, "                       %pR\n", res);
 		dev_info(&pdev->dev, "VF BAR%d: %pR (expanded to %d VFs for PE alignment)",
-				i, res, phb->ioda.total_pe);
+			 i, res, mul);
 	}
-	pdn->vfs_expanded = phb->ioda.total_pe;
+	pdn->vfs_expanded = mul;
 }
 #endif /* CONFIG_PCI_IOV */