1 files changed, 66 insertions, 0 deletions
diff --git a/gpxe/src/include/gpxe/nvs.h b/gpxe/src/include/gpxe/nvs.h
new file mode 100644
index 00000000..b026dd46
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+++ b/gpxe/src/include/gpxe/nvs.h
@@ -0,0 +1,66 @@
+#ifndef _GPXE_NVS_H
+#define _GPXE_NVS_H
+
+/** @file
+ *
+ * Non-volatile storage
+ *
+ */
+
+#include <stdint.h>
+
+/** A non-volatile storage device */
+struct nvs_device {
+	/** Word length
+	 *
+	 * This is expressed as the base-2 logarithm of the word
+	 * length in bytes.  A value of 0 therefore translates as
+	 * 8-bit words, and a value of 1 translates as 16-bit words.
+	 */
+	unsigned int word_len_log2;
+	/** Device size (in words) */
+	unsigned int size;
+	/** Data block size (in words)
+	 *
+	 * This is the block size used by the device.  It must be a
+	 * power of two.  Data reads and writes must not cross a block
+	 * boundary.
+	 *
+	 * Many devices allow reads to cross a block boundary, and
+	 * restrict only writes.  For the sake of simplicity, we
+	 * assume that the same restriction applies to both reads and
+	 * writes.
+	 */
+	unsigned int block_size;
+	/** Read data from 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
+	 *
+	 * Reads may not cross a block boundary.
+	 */
+	int ( * read ) ( struct nvs_device *nvs, unsigned int address,
+			 void *data, size_t len );
+	/** Write data to device
+	 *
+	 * @v nvs		NVS device
+	 * @v address		Address to which to write
+	 * @v data		Data buffer
+	 * @v len		Length of data buffer
+	 * @ret rc		Return status code
+	 *
+	 * Writes may not cross a block boundary.
+	 */
+	int ( * write ) ( struct nvs_device *nvs, unsigned int address,
+			  const void *data, size_t len );
+};
+
+extern int nvs_read ( struct nvs_device *nvs, unsigned int address,
+		      void *data, size_t len );
+extern int nvs_write ( struct nvs_device *nvs, unsigned int address,
+		       const void *data, size_t len );
+
+#endif /* _GPXE_NVS_H */