powerpc/powernv: Fix invalid IOMMU table

Ben found the root cause. Commit 37f02195bee9c25ce44e25204f40b7961a6d7c9d
("powerpc/pci: fix PCI-e devices rescan issue on powerpc platform")
overwrites the IOMMU table of PCI device while enabling PCI device.
The patch intends to fix the IOMMU table after that point.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

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

@@ -434,20 +434,21 @@ static void pnv_pci_ioda_setup_PEs(void)
 	}
 }
 
-static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *dev)
+static void pnv_pci_ioda_dma_dev_setup(struct pnv_phb *phb, struct pci_dev *pdev)
 {
-	/* We delay DMA setup after we have assigned all PE# */
-}
+	struct pci_dn *pdn = pnv_ioda_get_pdn(pdev);
+	struct pnv_ioda_pe *pe;
 
-static void pnv_ioda_setup_bus_dma(struct pnv_ioda_pe *pe, struct pci_bus *bus)
-{
-	struct pci_dev *dev;
+	/*
+	 * The function can be called while the PE#
+	 * hasn't been assigned. Do nothing for the
+	 * case.
+	 */
+	if (!pdn || pdn->pe_number == IODA_INVALID_PE)
+		return;
 
-	list_for_each_entry(dev, &bus->devices, bus_list) {
-		set_iommu_table_base(&dev->dev, &pe->tce32_table);
-		if (dev->subordinate)
-			pnv_ioda_setup_bus_dma(pe, dev->subordinate);
-	}
+	pe = &phb->ioda.pe_array[pdn->pe_number];
+	set_iommu_table_base(&pdev->dev, &pe->tce32_table);
 }
 
 static void pnv_pci_ioda1_tce_invalidate(struct iommu_table *tbl,
@@ -605,11 +606,6 @@ static void pnv_pci_ioda_setup_dma_pe(struct pnv_phb *phb,
 	}
 	iommu_init_table(tbl, phb->hose->node);
 
-	if (pe->pdev)
-		set_iommu_table_base(&pe->pdev->dev, tbl);
-	else
-		pnv_ioda_setup_bus_dma(pe, pe->pbus);
-
 	return;
  fail:
 	/* XXX Failure: Try to fallback to 64-bit only ? */
@@ -681,11 +677,6 @@ static void pnv_pci_ioda2_setup_dma_pe(struct pnv_phb *phb,
 	}
 	iommu_init_table(tbl, phb->hose->node);
 
-	if (pe->pdev)
-		set_iommu_table_base(&pe->pdev->dev, tbl);
-	else
-		pnv_ioda_setup_bus_dma(pe, pe->pbus);
-
 	return;
 fail:
 	if (pe->tce32_seg >= 0)