Abstracted out part of the concept of an SPI device to a generalised NVS

device.

Separated the mechanisms of non-volatile storage access and non-volatile
stored options.

src/drivers/nvs/nvs.c

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2006 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdint.h>
+#include <gpxe/nvs.h>
+
+/** @file
+ *
+ * Non-volatile storage
+ *
+ */
+
+int nvs_read ( struct nvs_device *nvs, unsigned int address,
+	       void *data, size_t len ) {
+	return nvs->read ( nvs, address, data, len );
+}

src/drivers/nvs/threewire.c

@@ -28,14 +28,15 @@
 
 /** Read data from three-wire device
  *
- * @v device		SPI device
+ * @v nvs		NVS device
  * @v address		Address from which to read
  * @v data		Data buffer
  * @v len		Length of data buffer
  * @ret rc		Return status code
  */
-int threewire_read ( struct spi_device *device, unsigned int address,
+int threewire_read ( struct nvs_device *nvs, unsigned int address,
 		     void *data, size_t len ) {
+	struct spi_device *device = nvs_to_spi ( nvs );
 	struct spi_bus *bus = device->bus;
 
 	assert ( bus->mode == SPI_MODE_THREEWIRE );