[efi] Identify autoboot device by MAC address when chainloading

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

src/arch/x86/prefix/efiprefix.c

@@ -24,6 +24,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/device.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
+#include <ipxe/efi/efi_autoboot.h>
 
 /**
  * EFI entry point
@@ -41,6 +42,9 @@ EFI_STATUS EFIAPI _efi_start ( EFI_HANDLE image_handle,
 	if ( ( efirc = efi_init ( image_handle, systab ) ) != 0 )
 		goto err_init;
 
+	/* Record autoboot device (if any) */
+	efi_set_autoboot();
+
 	/* Call to main() */
 	if ( ( rc = main() ) != 0 ) {
 		efirc = EFIRC ( rc );

src/include/ipxe/efi/efi_autoboot.h

@@ -0,0 +1,14 @@
+#ifndef _IPXE_EFI_AUTOBOOT_H
+#define _IPXE_EFI_AUTOBOOT_H
+
+/** @file
+ *
+ * EFI autoboot device
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+extern void efi_set_autoboot ( void );
+
+#endif /* _IPXE_EFI_AUTOBOOT_H */

src/interface/efi/efi_autoboot.c

@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2014 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/efi_autoboot.h>
+#include <ipxe/efi/Protocol/SimpleNetwork.h>
+#include <usr/autoboot.h>
+
+/** @file
+ *
+ * EFI autoboot device
+ *
+ */
+
+/** EFI simple network protocol GUID */
+static EFI_GUID efi_simple_network_protocol_guid
+	= EFI_SIMPLE_NETWORK_PROTOCOL_GUID;
+
+/**
+ * Identify autoboot device
+ *
+ */
+void efi_set_autoboot ( void ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	union {
+		EFI_SIMPLE_NETWORK_PROTOCOL *snp;
+		void *interface;
+	} snp;
+	EFI_SIMPLE_NETWORK_MODE *mode;
+	EFI_STATUS efirc;
+
+	/* Look for an SNP instance on the image's device handle */
+	if ( ( efirc = bs->OpenProtocol ( efi_loaded_image->DeviceHandle,
+					  &efi_simple_network_protocol_guid,
+					  &snp.interface, efi_image_handle,
+					  NULL,
+					  EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
+		DBGC ( efi_loaded_image, "EFI found no autoboot device\n" );
+		return;
+	}
+
+	/* Record autoboot device */
+	mode = snp.snp->Mode;
+	set_autoboot_ll_addr ( &mode->CurrentAddress, mode->HwAddressSize );
+	DBGC ( efi_loaded_image, "EFI found autoboot link-layer address:\n" );
+	DBGC_HDA ( efi_loaded_image, 0, &mode->CurrentAddress,
+		   mode->HwAddressSize );
+
+	/* Close protocol */
+	bs->CloseProtocol ( efi_loaded_image->DeviceHandle,
+			    &efi_simple_network_protocol_guid,
+			    efi_image_handle, NULL );
+}