drivers: Add API for NVRAM devices with byte level erase.

drivers/include/nvram.h

@@ -0,0 +1,87 @@
+/*
+ * Copyright (C) 2015 Eistec AB
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser General
+ * Public License v2.1. See the file LICENSE in the top level directory for more
+ * details.
+ */
+
+/**
+ * @defgroup    nvram Non-volatile RAM
+ * @ingroup     drivers
+ * @brief       Non-volatile RAM interface
+ *
+ * This API is designed around non-volatile memories which do not need blockwise
+ * erase, such as ferro-electric RAM (FRAM) or magneto-resistive RAM (MRAM).
+ *
+ * This interface is not suitable for flash memories.
+ *
+ * @{
+ *
+ * @file
+ *
+ * @brief       Generic non-volatile RAM driver interface
+ * @author      Joakim Gebart <joakim.gebart@eistec.se>
+ */
+
+#ifndef DRIVERS_NVRAM_H_
+#define DRIVERS_NVRAM_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Forward declaration in order to declare function pointers which take this
+ * type as a parameter within the struct. */
+struct nvram;
+
+/**
+ * @brief Device descriptor for generic NVRAM devices.
+ */
+typedef struct nvram {
+    /**
+     * @brief Pointer to device-specific read function
+     *
+     * Copy data from system memory to NVRAM.
+     *
+     * @param[in]  dev   Pointer to NVRAM device descriptor
+     * @param[out] dst   Pointer to the first byte in the system memory address space
+     * @param[in]  src   Starting address in the NVRAM device address space
+     * @param[in]  len   Number of bytes to copy
+     *
+     * @return           Number of bytes read on success
+     * @return           <0 on errors
+     */
+    int (*read)(struct nvram *dev, uint8_t *dst, uint32_t src, size_t size);
+
+    /**
+     * @brief Pointer to device-specific write function
+     *
+     * Copy data from NVRAM to system memory.
+     *
+     * @param[in]  dev   Pointer to NVRAM device descriptor
+     * @param[in]  src   Pointer to the first byte in the system memory address space
+     * @param[in]  dst   Starting address in the NVRAM device address space
+     * @param[in]  len   Number of bytes to copy
+     *
+     * @return           Number of bytes written on success
+     * @return           <0 on errors
+     */
+    int (*write)(struct nvram *dev, uint8_t *src, uint32_t dst, size_t size);
+
+    /** @brief Device capacity */
+    size_t size;
+
+    /** @brief Device-specific parameters, if any. */
+    void *extra;
+} nvram_t;
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DRIVERS_NVRAM_H_ */
+/** @} */