arm: implement find_next_zero_bit function

This commit copies implementation of the find_next_zero_bit() from
git://git.denx.de/u-boot.git/arch/mips/include/asm/bitops.h. v2014.07

The function is required to enable MCAST_TFTP support for ARM platforms.

Signed-off-by: Vitaly Andrianov <vitalya@ti.com>

diff --git a/arch/arm/include/asm/bitops.h b/arch/arm/include/asm/bitops.h
index 597dafb..9b78043 100644 (file)
--- a/arch/arm/include/asm/bitops.h
+++ b/arch/arm/include/asm/bitops.h
@@ -95,9 +95,6 @@ static inline int __test_and_change_bit(int nr, volatile void *addr)
        return (old & mask) != 0;
 }
 
-extern int find_first_zero_bit(void * addr, unsigned size);
-extern int find_next_zero_bit(void * addr, int size, int offset);
-
 /*
  * This routine doesn't need to be atomic.
  */
@@ -129,6 +126,43 @@ static inline unsigned long ffz(unsigned long word)
        return k;
 }
 
+static inline int find_next_zero_bit(void *addr, int size, int offset)
+{
+       unsigned long *p = ((unsigned long *)addr) + (offset >> 5);
+       unsigned long result = offset & ~31UL;
+       unsigned long tmp;
+
+       if (offset >= size)
+               return size;
+       size -= result;
+       offset &= 31UL;
+       if (offset) {
+               tmp = *(p++);
+               tmp |= ~0UL >> (32-offset);
+               if (size < 32)
+                       goto found_first;
+               if (~tmp)
+                       goto found_middle;
+               size -= 32;
+               result += 32;
+       }
+       while (size & ~31UL) {
+               tmp = *(p++);
+               if (~tmp)
+                       goto found_middle;
+               result += 32;
+               size -= 32;
+       }
+       if (!size)
+               return result;
+       tmp = *p;
+
+found_first:
+       tmp |= ~0UL >> size;
+found_middle:
+       return result + ffz(tmp);
+}
+
 /*
  * hweightN: returns the hamming weight (i.e. the number
  * of bits set) of a N-bit word
@@ -138,6 +172,9 @@ static inline unsigned long ffz(unsigned long word)
 #define hweight16(x) generic_hweight16(x)
 #define hweight8(x) generic_hweight8(x)
 
+#define find_first_zero_bit(addr, size) \
+       find_next_zero_bit((addr), (size), 0)
+
 #define ext2_set_bit                   test_and_set_bit
 #define ext2_clear_bit                 test_and_clear_bit
 #define ext2_test_bit                  test_bit