[efi] Include NII driver within "snp" and "snponly" build targets

End users almost certainly don't care whether the underlying interface
is SNP or NII/UNDI.  Try to minimise surprise and unnecessary
documentation by including the NII driver whenever the SNP driver is
requested.

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

src/drivers/net/efi/nii.c

@@ -28,10 +28,11 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/umalloc.h>
 #include <ipxe/efi/efi.h>
 #include <ipxe/efi/efi_driver.h>
-#include <ipxe/efi/efi_snp.h>
 #include <ipxe/efi/efi_pci.h>
 #include <ipxe/efi/efi_utils.h>
+#include <ipxe/efi/Protocol/NetworkInterfaceIdentifier.h>
 #include <ipxe/efi/IndustryStandard/Acpi10.h>
+#include "nii.h"
 
 /** @file
  *
@@ -955,45 +956,13 @@ static struct net_device_operations nii_operations = {
 	.poll = nii_poll,
 };
 
-/**
- * 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 ) {
-	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
-	EFI_STATUS efirc;
-
-	/* Check that this is not a device we are providing ourselves */
-	if ( find_snpdev ( device ) != NULL ) {
-		DBGCP ( device, "NII %p %s is provided by this binary\n",
-			device, efi_handle_name ( device ) );
-		return -ENOTTY;
-	}
-
-	/* 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 %p %s is not an NII device\n",
-			device, efi_handle_name ( device ) );
-		return -EEFI ( efirc );
-	}
-	DBGC ( device, "NII %p %s is an NII device\n",
-	       device, efi_handle_name ( device ) );
-
-	return 0;
-}
-
 /**
  * Attach driver to device
  *
  * @v efidev		EFI device
  * @ret rc		Return status code
  */
-static int nii_start ( struct efi_device *efidev ) {
+int nii_start ( struct efi_device *efidev ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	EFI_HANDLE device = efidev->device;
 	struct net_device *netdev;
@@ -1106,7 +1075,7 @@ static int nii_start ( struct efi_device *efidev ) {
  *
  * @v efidev		EFI device
  */
-static void nii_stop ( struct efi_device *efidev ) {
+void nii_stop ( struct efi_device *efidev ) {
 	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
 	struct net_device *netdev = efidev_get_drvdata ( efidev );
 	struct nii_nic *nii = netdev->priv;
@@ -1130,11 +1099,3 @@ static void nii_stop ( struct efi_device *efidev ) {
 	netdev_nullify ( netdev );
 	netdev_put ( netdev );
 }
-
-/** EFI NII driver */
-struct efi_driver nii_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
-	.name = "NII",
-	.supported = nii_supported,
-	.start = nii_start,
-	.stop = nii_stop,
-};

src/drivers/net/efi/nii.h

@@ -0,0 +1,17 @@
+#ifndef _NII_H
+#define _NII_H
+
+/** @file
+ *
+ * NII driver
+ *
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+struct efi_device;
+
+extern int nii_start ( struct efi_device *efidev );
+extern void nii_stop ( struct efi_device *efidev );
+
+#endif /* _NII_H */

src/drivers/net/efi/snp.c

@@ -24,6 +24,7 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <ipxe/efi/efi_driver.h>
 #include <ipxe/efi/efi_snp.h>
 #include "snpnet.h"
+#include "nii.h"
 
 /** @file
  *
@@ -63,10 +64,50 @@ static int snp_supported ( EFI_HANDLE device ) {
 	return 0;
 }
 
+/**
+ * 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 ) {
+	EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
+	EFI_STATUS efirc;
+
+	/* Check that this is not a device we are providing ourselves */
+	if ( find_snpdev ( device ) != NULL ) {
+		DBGCP ( device, "NII %p %s is provided by this binary\n",
+			device, efi_handle_name ( device ) );
+		return -ENOTTY;
+	}
+
+	/* 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 %p %s is not an NII device\n",
+			device, efi_handle_name ( device ) );
+		return -EEFI ( efirc );
+	}
+	DBGC ( device, "NII %p %s is an NII device\n",
+	       device, efi_handle_name ( device ) );
+
+	return 0;
+}
+
 /** EFI SNP driver */
 struct efi_driver snp_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
 	.name = "SNP",
 	.supported = snp_supported,
 	.start = snpnet_start,
 	.stop = snpnet_stop,
 };
+
+/** EFI NII driver */
+struct efi_driver nii_driver __efi_driver ( EFI_DRIVER_NORMAL ) = {
+	.name = "NII",
+	.supported = nii_supported,
+	.start = nii_start,
+	.stop = nii_stop,
+};