1 files changed, 36 insertions, 30 deletions

diff --git a/src/drivers/net/efi/snp.c b/src/drivers/net/efi/snp.c
index fbd6069..1920cdb 100644
--- a/src/drivers/net/efi/snp.c
+++ b/src/drivers/net/efi/snp.c
@@ -27,6 +27,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/efi_snp.h>
+#include <ipxe/efi/efi_utils.h>
 #include "snpnet.h"
 #include "nii.h"
 
@@ -40,31 +41,46 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  * Check to see if driver supports a device
  *
  * @v device		EFI device handle
+ * @v protocol		Protocol GUID
  * @ret rc		Return status code
  */
-static int snp_supported ( EFI_HANDLE device ) {
+static int snp_nii_supported ( EFI_HANDLE device, EFI_GUID *protocol ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_HANDLE parent;
 	EFI_STATUS efirc;
+	int rc;
 
 	/* Check that this is not a device we are providing ourselves */
 	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "SNP %s is provided by this binary\n",
+		DBGCP ( device, "HANDLE %s is provided by this binary\n",
 			efi_handle_name ( device ) );
 		return -ENOTTY;
 	}
 
-	/* Test for presence of simple network protocol */
-	if ( ( efirc = bs->OpenProtocol ( device,
-					  &efi_simple_network_protocol_guid,
+	/* Test for presence of protocol */
+	if ( ( efirc = bs->OpenProtocol ( device, protocol,
 					  NULL, efi_image_handle, device,
 					  EFI_OPEN_PROTOCOL_TEST_PROTOCOL))!=0){
-		DBGCP ( device, "SNP %s is not an SNP device\n",
-			efi_handle_name ( device ) );
+		DBGCP ( device, "HANDLE %s is not a %s device\n",
+			efi_handle_name ( device ),
+			efi_guid_ntoa ( protocol ) );
 		return -EEFI ( efirc );
 	}
-	DBGC ( device, "SNP %s is an SNP device\n",
-	       efi_handle_name ( device ) );
 
+	/* Check that there are no instances of this protocol further
+	 * up this device path.
+	 */
+	if ( ( rc = efi_locate_device ( device, protocol,
+					&parent, 1 ) ) == 0 ) {
+		DBGC2 ( device, "HANDLE %s has %s-supporting parent ",
+			efi_handle_name ( device ),
+			efi_guid_ntoa ( protocol ) );
+		DBGC2 ( device, "%s\n", efi_handle_name ( parent ) );
+		return -ENOTTY;
+	}
+
+	DBGC ( device, "HANDLE %s is a %s device\n",
+	       efi_handle_name ( device ), efi_guid_ntoa ( protocol ) );
 	return 0;
 }
 
@@ -74,30 +90,20 @@ static int snp_supported ( EFI_HANDLE device ) {
  * @v device		EFI device handle
  * @ret rc		Return status code
  */
-static int nii_supported ( EFI_HANDLE device ) {
-	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
-	EFI_STATUS efirc;
+static int snp_supported ( EFI_HANDLE device ) {
 
-	/* Check that this is not a device we are providing ourselves */
-	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "NII %s is provided by this binary\n",
-			efi_handle_name ( device ) );
-		return -ENOTTY;
-	}
+	return snp_nii_supported ( device, &efi_simple_network_protocol_guid );
+}
 
-	/* Test for presence of NII protocol */
-	if ( ( efirc = bs->OpenProtocol ( device,
-					  &efi_nii31_protocol_guid,
-					  NULL, efi_image_handle, device,
-					  EFI_OPEN_PROTOCOL_TEST_PROTOCOL))!=0){
-		DBGCP ( device, "NII %s is not an NII device\n",
-			efi_handle_name ( device ) );
-		return -EEFI ( efirc );
-	}
-	DBGC ( device, "NII %s is an NII device\n",
-	       efi_handle_name ( device ) );
+/**
+ * Check to see if driver supports a device
+ *
+ * @v device		EFI device handle
+ * @ret rc		Return status code
+ */
+static int nii_supported ( EFI_HANDLE device ) {
 
-	return 0;
+	return snp_nii_supported ( device, &efi_nii31_protocol_guid );
 }
 
 /** EFI SNP driver */