[efi] Fall back to assuming identity mapping of MMIO address space

Some UEFI systems (observed with a Supermicro X11SPG-TF motherboard) seem to fail to provide a valid ACPI address space descriptor for the MMIO address space associated with a PCI root bridge. If no valid descriptor can be found, fall back to assuming that the MMIO address space is identity mapped, thereby matching the behaviour prior to commit 27e886c ("[efi] Use address offset as reported by EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL"). Debugged-by: Tore Anderson <tore@fud.no> Signed-off-by: Michael Brown <mcb30@ipxe.org>
ipxe · Oct 30, 2020 · 9b25f6e · 9b25f6e
1 parent 1687370
commit 9b25f6e
Showing 1 changed file with 2 additions and 4 deletions.
diff --git a/src/interface/efi/efi_pci.c b/src/interface/efi/efi_pci.c
@@ -244,7 +244,6 @@ void * efipci_ioremap ( struct pci_device *pci, unsigned long bus_addr,
 	uint64_t offset;
 	uint64_t start;
 	uint64_t end;
-	void *io_addr = NULL;
 	EFI_STATUS efirc;
 	int rc;
 
@@ -282,10 +281,9 @@ void * efipci_ioremap ( struct pci_device *pci, unsigned long bus_addr,
 			PCI_ARGS ( pci ), bus_addr, len );
 		bus_addr -= offset;
 		DBGC2 ( pci, "%08lx\n", bus_addr );
-		io_addr = ioremap ( bus_addr, len );
 		break;
 	}
-	if ( ! io_addr ) {
+	if ( tag == ACPI_END_RESOURCE ) {
 		DBGC ( pci, "EFIPCI " PCI_FMT " %08lx+%zx is not within "
 		       "root bridge address space\n",
 		       PCI_ARGS ( pci ), bus_addr, len );
@@ -294,7 +292,7 @@ void * efipci_ioremap ( struct pci_device *pci, unsigned long bus_addr,
  err_config:
 	efipci_root_close ( handle );
  err_root:
-	return io_addr;
+	return ioremap ( bus_addr, len );
 }
 
 PROVIDE_PCIAPI_INLINE ( efi, pci_num_bus );