bitmap: add bitmap_copy_le()

bitmap_copy_le() copies a bitmap, putting the bits into little-endian
order (i.e., each unsigned long word in the bitmap is put into
little-endian order).

The UWB stack used bitmaps to manage Medium Access Slot availability,
and these bitmaps need to be written to the hardware in LE order.

Signed-off-by: David Vrabel <david.vrabel@csr.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 89781fd..5379913 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -130,6 +130,7 @@ extern void bitmap_fold(unsigned long *dst, const unsigned long *orig,
 extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
 extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
 extern int bitmap_allocate_region(unsigned long *bitmap, int pos, int order);
+extern void bitmap_copy_le(void *dst, const unsigned long *src, int nbits);
 
 #define BITMAP_LAST_WORD_MASK(nbits)					\
 (									\
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 06fb57c..c2006bf 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -1007,3 +1007,25 @@ int bitmap_allocate_region(unsigned long *bitmap, int pos, int order)
 	return 0;
 }
 EXPORT_SYMBOL(bitmap_allocate_region);
+
+/**
+ * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
+ * @dst:   destination buffer
+ * @src:   bitmap to copy
+ * @nbits: number of bits in the bitmap
+ *
+ * Require nbits % BITS_PER_LONG == 0.
+ */
+void bitmap_copy_le(void *dst, const unsigned long *src, int nbits)
+{
+	unsigned long *d = dst;
+	int i;
+
+	for (i = 0; i < nbits/BITS_PER_LONG; i++) {
+		if (BITS_PER_LONG == 64)
+			d[i] = cpu_to_le64(src[i]);
+		else
+			d[i] = cpu_to_le32(src[i]);
+	}
+}
+EXPORT_SYMBOL(bitmap_copy_le);