kernel: devfs: Add devfs_get_dev()

Add helper to get a device descriptor from a vnode

Signed-off-by: Ian Moffett <ian@osmora.org>

2 files changed, 24 insertions, 0 deletions

diff --git a/sys/fs/devfs.c b/sys/fs/devfs.c
index 7e7fd9d..8b273db 100644
--- a/sys/fs/devfs.c
+++ b/sys/fs/devfs.c
@@ -199,6 +199,29 @@ devfs_add_dev(const char *name, const struct device *dev)
     return 0;
 }
 
+/*
+ * Fetch a device descriptor from a vnode.
+ */
+int
+devfs_get_dev(struct vnode *vp, struct device **res)
+{
+    struct device_node *n;
+    struct device *dev;
+
+    /* Is this really a device? */
+    if (vp->type != VBLK && vp->type != VCHR) {
+        return -ENODEV;
+    }
+
+    n = vp->data;
+    if ((dev = device_fetch(n->major, n->minor)) == NULL) {
+        return -ENODEV;
+    }
+
+    *res = dev;
+    return 0;
+}
+
 struct vfsops g_devfs_ops = {
     .init = devfs_init
 };
diff --git a/sys/include/fs/devfs.h b/sys/include/fs/devfs.h
index 7f32f8c..66128ef 100644
--- a/sys/include/fs/devfs.h
+++ b/sys/include/fs/devfs.h
@@ -37,5 +37,6 @@ extern struct vfsops g_devfs_ops;
 extern struct vops g_devfs_vops;
 
 int devfs_add_dev(const char *name, const struct device *dev);
+int devfs_get_dev(struct vnode *vp, struct device **res);
 
 #endif