[PATCH v2 1/2] lib: sbi: Fix __atomic_op_bit_ord and comments

[Xiang W]

The original code returns the value of the word before modification.
When modifying the upper 32 bits under RV64, the value returned via
int return will have no meaning. Corrected to return the value of the
bit. And modify the function description.

Signed-off-by: Xiang W <wxjstz at 126.com>
---
 include/sbi/riscv_atomic.h | 8 ++++----
 lib/sbi/riscv_atomic.c     | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/include/sbi/riscv_atomic.h b/include/sbi/riscv_atomic.h
index 3972e0b..c5aa05e 100644
--- a/include/sbi/riscv_atomic.h
+++ b/include/sbi/riscv_atomic.h
@@ -39,14 +39,14 @@ unsigned int atomic_raw_xchg_uint(volatile unsigned int *ptr,
 unsigned long atomic_raw_xchg_ulong(volatile unsigned long *ptr,
 				    unsigned long newval);
 /**
- * Set a bit in an atomic variable and return the new value.
+ * Set a bit in an atomic variable and return the value of bit before modify.
  * @nr : Bit to set.
  * @atom: atomic variable to modify
  */
 int atomic_set_bit(int nr, atomic_t *atom);
 
 /**
- * Clear a bit in an atomic variable and return the new value.
+ * Clear a bit in an atomic variable and return the value of bit before modify.
  * @nr : Bit to set.
  * @atom: atomic variable to modify
  */
@@ -54,14 +54,14 @@ int atomic_set_bit(int nr, atomic_t *atom);
 int atomic_clear_bit(int nr, atomic_t *atom);
 
 /**
- * Set a bit in any address and return the new value .
+ * Set a bit in any address and return the value of bit before modify.
  * @nr : Bit to set.
  * @addr: Address to modify
  */
 int atomic_raw_set_bit(int nr, volatile unsigned long *addr);
 
 /**
- * Clear a bit in any address and return the new value .
+ * Clear a bit in any address and return the value of bit before modify.
  * @nr : Bit to set.
  * @addr: Address to modify
  */
diff --git a/lib/sbi/riscv_atomic.c b/lib/sbi/riscv_atomic.c
index 528686f..477f709 100644
--- a/lib/sbi/riscv_atomic.c
+++ b/lib/sbi/riscv_atomic.c
@@ -222,7 +222,7 @@ unsigned long atomic_raw_xchg_ulong(volatile unsigned long *ptr,
 				     : "=r"(__res), "+A"(addr[BIT_WORD(nr)]) \
 				     : "r"(mod(__mask))                      \
 				     : "memory");                            \
-		__res;                                                       \
+		__res & mask ? 1 : 0;                                        \
 	})
 
 #define __atomic_op_bit(op, mod, nr, addr) \
-- 
2.42.0