[U-Boot] [PATCH] MIPS: add atomic operations support.

[Govindraj Raja]

some of the u-boot frameworks like ubi-fs and eth_gadget
uses atomic_* api's. So add atomic api's for mips.

This makes ubi-fs on nand work with mips platform.

Signed-off-by: Govindraj Raja <Govindraj.Raja at imgtec.com>
---
 arch/mips/include/asm/atomic.h | 90 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 arch/mips/include/asm/atomic.h

diff --git a/arch/mips/include/asm/atomic.h b/arch/mips/include/asm/atomic.h
new file mode 100644
index 0000000..163e7e2
--- /dev/null
+++ b/arch/mips/include/asm/atomic.h
@@ -0,0 +1,90 @@
+/*
+ * Based on: linux/arch/mips/include/asm/atomic.h
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __ASM_MIPS_ATOMIC_H
+#define __ASM_MIPS_ATOMIC_H
+
+typedef struct { volatile int counter; } atomic_t;
+
+#define ATOMIC_INIT(i)	{ (i) }
+
+#include <asm/system.h>
+
+#define atomic_read(v)		((v)->counter)
+#define atomic_set(v, i)	(((v)->counter) = (i))
+
+static inline void atomic_add(int i, volatile atomic_t *v)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	v->counter += i;
+	local_irq_restore(flags);
+}
+
+static inline void atomic_sub(int i, volatile atomic_t *v)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	v->counter -= i;
+	local_irq_restore(flags);
+}
+
+static inline void atomic_inc(volatile atomic_t *v)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	v->counter += 1;
+	local_irq_restore(flags);
+}
+
+static inline void atomic_dec(volatile atomic_t *v)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	v->counter -= 1;
+	local_irq_restore(flags);
+}
+
+static inline int atomic_dec_and_test(volatile atomic_t *v)
+{
+	unsigned long flags;
+	int val;
+
+	local_irq_save(flags);
+	val = v->counter;
+	v->counter = val -= 1;
+	local_irq_restore(flags);
+
+	return val == 0;
+}
+
+static inline int atomic_add_negative(int i, volatile atomic_t *v)
+{
+	unsigned long flags;
+	int val;
+
+	local_irq_save(flags);
+	val = v->counter;
+	v->counter = val += i;
+	local_irq_restore(flags);
+
+	return val < 0;
+}
+
+static inline void atomic_clear_mask(unsigned long mask, unsigned long *addr)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	*addr &= ~mask;
+	local_irq_restore(flags);
+}
+
+#endif /* __ASM_MIPS_ATOMIC_H */
-- 
1.9.1