[efi] Retain a long-lived reference to the EFI_PCI_IO_PROTOCOL instance

Provide opened EFI PCI devices with access to the underlying
EFI_PCI_IO_PROTOCOL instance, in order to facilitate the future use of
the DMA mapping methods within the fast data path.

Do not require the use of this stored EFI_PCI_IO_PROTOCOL instance for
memory-mapped I/O (since the entire point of memory-mapped I/O as a
concept is to avoid this kind of unnecessary complexity) or for
slow-path PCI configuration space accesses (since these may be
required for access to PCI bus:dev.fn addresses that do not correspond
to a device bound via our driver binding protocol instance).

Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/src/include/ipxe/efi/efi_pci.h b/src/include/ipxe/efi/efi_pci.h
index 6dd945f05..2ea1a8f0e 100644
--- a/src/include/ipxe/efi/efi_pci.h
+++ b/src/include/ipxe/efi/efi_pci.h
@@ -17,9 +17,17 @@ static inline EFIAPI uint64_t LShiftU64 ( UINT64 value, UINTN shift ) {
 	return ( value << shift );
 }
 
+/** An EFI PCI device */
+struct efi_pci_device {
+	/** PCI device */
+	struct pci_device pci;
+	/** PCI I/O protocol */
+	EFI_PCI_IO_PROTOCOL *io;
+};
+
 extern int efipci_open ( EFI_HANDLE device, UINT32 attributes,
-			 struct pci_device *pci );
+			 struct efi_pci_device *efipci );
 extern void efipci_close ( EFI_HANDLE device );
-extern int efipci_info ( EFI_HANDLE device, struct pci_device *pci );
+extern int efipci_info ( EFI_HANDLE device, struct efi_pci_device *efipci );
 
 #endif /* _IPXE_EFI_PCI_H */