NOMMU: Present backing device capabilities for MTD chardevs
Present backing device capabilities for MTD character device files to allow
NOMMU mmap to do direct mapping where possible.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Bernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/mtd/devices/mtdram.c b/drivers/mtd/devices/mtdram.c
index 3aaca88..fce5ff7 100644
--- a/drivers/mtd/devices/mtdram.c
+++ b/drivers/mtd/devices/mtdram.c
@@ -65,6 +65,19 @@
{
}
+/*
+ * Allow NOMMU mmap() to directly map the device (if not NULL)
+ * - return the address to which the offset maps
+ * - return -ENOSYS to indicate refusal to do the mapping
+ */
+static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,
+ unsigned long len,
+ unsigned long offset,
+ unsigned long flags)
+{
+ return (unsigned long) mtd->priv + offset;
+}
+
static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,
size_t *retlen, u_char *buf)
{
@@ -116,6 +129,7 @@
mtd->erase = ram_erase;
mtd->point = ram_point;
mtd->unpoint = ram_unpoint;
+ mtd->get_unmapped_area = ram_get_unmapped_area;
mtd->read = ram_read;
mtd->write = ram_write;