[int13] Add infrastructure to support EDD version 4.0

Support the extensions mandated by EDD 4.0, including:

 o  the ability to specify a flat physical address in a disk address
    packet,

 o  the ability to specify a sector count greater than 127 in a disk
    address packet,

 o  support for all functions within the Fixed Disk Access and EDD
    Support subsets,

 o  the ability to describe a device using EDD Device Path Information.

This implementation is based on draft revision 3 of the EDD 4.0
specification, with reference to the EDD 3.0 specification.  It is
possible that this implementation may need to change in order to
conform to the final published EDD 4.0 specification.

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

1 files changed, 26 insertions, 1 deletions

diff --git a/src/core/device.c b/src/core/device.c
index 1a227fd9..cb2c23b0 100644
--- a/src/core/device.c
+++ b/src/core/device.c
@@ -21,8 +21,9 @@ FILE_LICENCE ( GPL2_OR_LATER );
 #include <string.h>
 #include <ipxe/list.h>
 #include <ipxe/tables.h>
-#include <ipxe/device.h>
 #include <ipxe/init.h>
+#include <ipxe/interface.h>
+#include <ipxe/device.h>
 
 /**
  * @file
@@ -105,3 +106,27 @@ struct startup_fn startup_devices __startup_fn ( STARTUP_NORMAL ) = {
 	.startup = probe_devices,
 	.shutdown = remove_devices,
 };
+
+/**
+ * Identify a device behind an interface
+ *
+ * @v intf		Interface
+ * @ret device		Device, or NULL
+ */
+struct device * identify_device ( struct interface *intf ) {
+	struct interface *dest;
+	identify_device_TYPE ( void * ) *op =
+		intf_get_dest_op ( intf, identify_device, &dest );
+	void *object = intf_object ( dest );
+	void *device;
+
+	if ( op ) {
+		device = op ( object );
+	} else {
+		/* Default is to return NULL */
+		device = NULL;
+	}
+
+	intf_put ( dest );
+	return device;
+}