From 171748f83c8df92358f4cd1b9ff37c520ff52e68 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Joakim=20Nohlg=C3=A5rd?= <joakim.nohlgard@eistec.se>
Date: Tue, 12 Jul 2016 07:58:42 +0200
Subject: [PATCH] drivers/nvram: Add vfs compatible functions

---
 drivers/Makefile.dep      |   1 +
 drivers/include/nvram.h   |   8 +++
 drivers/nvram/Makefile    |   3 +
 drivers/nvram/nvram-vfs.c | 136 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 148 insertions(+)
 create mode 100644 drivers/nvram/Makefile
 create mode 100644 drivers/nvram/nvram-vfs.c

diff --git a/drivers/Makefile.dep b/drivers/Makefile.dep
index 558ff0e35a6d..67b72ba398fd 100644
--- a/drivers/Makefile.dep
+++ b/drivers/Makefile.dep
@@ -150,6 +150,7 @@ ifneq (,$(filter nrfmin,$(USEMODULE)))
 endif
 
 ifneq (,$(filter nvram_spi,$(USEMODULE)))
+    USEMODULE += nvram
     USEMODULE += xtimer
 endif
 
diff --git a/drivers/include/nvram.h b/drivers/include/nvram.h
index 6bc79feff6d0..4eab01be30c4 100644
--- a/drivers/include/nvram.h
+++ b/drivers/include/nvram.h
@@ -30,6 +30,10 @@
 #include <stdint.h>
 #include <stddef.h>
 
+#if MODULE_VFS
+#include "vfs.h"
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -79,6 +83,10 @@ typedef struct nvram {
     void *extra;
 } nvram_t;
 
+#if MODULE_VFS
+extern const vfs_file_ops_t nvram_vfs_ops;
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/drivers/nvram/Makefile b/drivers/nvram/Makefile
new file mode 100644
index 000000000000..48055ad6339b
--- /dev/null
+++ b/drivers/nvram/Makefile
@@ -0,0 +1,3 @@
+MODULE = nvram
+
+include $(RIOTBASE)/Makefile.base
diff --git a/drivers/nvram/nvram-vfs.c b/drivers/nvram/nvram-vfs.c
new file mode 100644
index 000000000000..9118ae60d527
--- /dev/null
+++ b/drivers/nvram/nvram-vfs.c
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#if MODULE_VFS
+
+#include <fcntl.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "nvram.h"
+#include "vfs.h"
+
+/**
+ * @ingroup     nvram
+ * @{
+ *
+ * @file
+ *
+ * @brief       NVRAM generic VFS operations
+ *
+ * This allows the nvram driver to register as a node on DevFS
+ *
+ * See boards/mulle or tests/unittests/tests-devfs for examples on how to use.
+ *
+ * Tested with nvram_spi on Mulle
+ *
+ * @author      Joakim Nohlgård <joakim.nohlgard@eistec.se>
+ */
+
+static int nvram_vfs_fstat(vfs_file_t *filp, struct stat *buf);
+static off_t nvram_vfs_lseek(vfs_file_t *filp, off_t off, int whence);
+static ssize_t nvram_vfs_read(vfs_file_t *filp, void *dest, size_t nbytes);
+static ssize_t nvram_vfs_write(vfs_file_t *filp, const void *src, size_t nbytes);
+
+const vfs_file_ops_t nvram_vfs_ops = {
+    .fstat = nvram_vfs_fstat,
+    .lseek = nvram_vfs_lseek,
+    .read  = nvram_vfs_read,
+    .write = nvram_vfs_write,
+};
+
+static int nvram_vfs_fstat(vfs_file_t *filp, struct stat *buf)
+{
+    if (buf == NULL) {
+        return -EFAULT;
+    }
+    nvram_t *dev = filp->private_data.ptr;
+    if (dev == NULL) {
+        return -EFAULT;
+    }
+    buf->st_nlink = 1;
+    buf->st_size = dev->size;
+    return 0;
+}
+
+static off_t nvram_vfs_lseek(vfs_file_t *filp, off_t off, int whence)
+{
+    nvram_t *dev = filp->private_data.ptr;
+    if (dev == NULL) {
+        return -EFAULT;
+    }
+    switch (whence) {
+        case SEEK_SET:
+            break;
+        case SEEK_CUR:
+            off += filp->pos;
+            break;
+        case SEEK_END:
+            off += dev->size;
+            break;
+        default:
+            return -EINVAL;
+    }
+    if (off < 0) {
+        /* the resulting file offset would be negative */
+        return -EINVAL;
+    }
+    /* POSIX allows seeking past the end of the file */
+    filp->pos = off;
+    return off;
+}
+
+static ssize_t nvram_vfs_read(vfs_file_t *filp, void *dest, size_t nbytes)
+{
+    nvram_t *dev = filp->private_data.ptr;
+    if (dev == NULL) {
+        return -EFAULT;
+    }
+    uint32_t src = filp->pos;
+    if (src >= dev->size) {
+        return 0;
+    }
+    if (src + nbytes > dev->size) {
+        nbytes = dev->size - src;
+    }
+    int res = dev->read(dev, dest, src, nbytes);
+    if (res < 0) {
+        return res;
+    }
+    /* Advance file position */
+    filp->pos += res;
+    return res;
+}
+
+static ssize_t nvram_vfs_write(vfs_file_t *filp, const void *src, size_t nbytes)
+{
+    nvram_t *dev = filp->private_data.ptr;
+    if (dev == NULL) {
+        return -EFAULT;
+    }
+    uint32_t dest = filp->pos;
+    if (dest >= dev->size) {
+        return 0;
+    }
+    if (dest + nbytes > dev->size) {
+        nbytes = dev->size - dest;
+    }
+    int res = dev->write(dev, src, dest, nbytes);
+    if (res < 0) {
+        return res;
+    }
+    /* Advance file position */
+    filp->pos += res;
+    return res;
+}
+
+/** @} */
+
+#else
+typedef int dont_be_pedantic;
+#endif /* MODULE_VFS */