x86/PCI: Enable AMD 64-bit window on resume

Reenable the 64-bit window during resume.

Fixes: fa564ad9 ("x86/PCI: Enable a 64bit BAR on AMD Family 15h (Models 00-1f, 30-3f, 60-7f)")
Reported-by: Tom St Denis <tom.stdenis@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

arch/x86/pci/fixup.c

@@ -662,11 +662,11 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x2033, quirk_no_aersid);
  */
 static void pci_amd_enable_64bit_bar(struct pci_dev *dev)
 {
+	static const char *name = "PCI Bus 0000:00";
+	struct resource *res, *conflict;
 	u32 base, limit, high;
 	struct pci_dev *other;
-	struct resource *res;
 	unsigned i;
-	int r;
 
 	if (!(pci_probe & PCI_BIG_ROOT_WINDOW))
 		return;
@@ -707,21 +707,26 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev)
 	 * Allocate a 256GB window directly below the 0xfd00000000 hardware
 	 * limit (see AMD Family 15h Models 30h-3Fh BKDG, sec 2.4.6).
 	 */
-	res->name = "PCI Bus 0000:00";
+	res->name = name;
 	res->flags = IORESOURCE_PREFETCH | IORESOURCE_MEM |
 		IORESOURCE_MEM_64 | IORESOURCE_WINDOW;
 	res->start = 0xbd00000000ull;
 	res->end = 0xfd00000000ull - 1;
 
-	r = request_resource(&iomem_resource, res);
-	if (r) {
+	conflict = request_resource_conflict(&iomem_resource, res);
+	if (conflict) {
 		kfree(res);
+		if (conflict->name != name)
 			return;
-	}
 
+		/* We are resuming from suspend; just reenable the window */
+		res = conflict;
+	} else {
 		dev_info(&dev->dev, "adding root bus resource %pR (tainting kernel)\n",
 			 res);
 		add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
+		pci_bus_add_resource(dev->bus, res, 0);
+	}
 
 	base = ((res->start >> 8) & AMD_141b_MMIO_BASE_MMIOBASE_MASK) |
 		AMD_141b_MMIO_BASE_RE_MASK | AMD_141b_MMIO_BASE_WE_MASK;
@@ -733,13 +738,16 @@ static void pci_amd_enable_64bit_bar(struct pci_dev *dev)
 	pci_write_config_dword(dev, AMD_141b_MMIO_HIGH(i), high);
 	pci_write_config_dword(dev, AMD_141b_MMIO_LIMIT(i), limit);
 	pci_write_config_dword(dev, AMD_141b_MMIO_BASE(i), base);
-
-	pci_bus_add_resource(dev->bus, res, 0);
 }
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1401, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x141b, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1571, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x15b1, pci_amd_enable_64bit_bar);
 DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, 0x1601, pci_amd_enable_64bit_bar);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1401, pci_amd_enable_64bit_bar);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x141b, pci_amd_enable_64bit_bar);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1571, pci_amd_enable_64bit_bar);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x15b1, pci_amd_enable_64bit_bar);
+DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_AMD, 0x1601, pci_amd_enable_64bit_bar);
 
 #endif