sh: Split out atomic ops logically.

We have a few different ways to do the atomic operations, so split
them out in to different headers rather than bloating atomic.h.
Kernelspace gUSA will take this up to a third implementation.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 107 insertions, 0 deletions

diff --git a/include/asm-sh/atomic-llsc.h b/include/asm-sh/atomic-llsc.h
new file mode 100644
index 0000000..4b00b78
--- /dev/null
+++ b/include/asm-sh/atomic-llsc.h
@@ -0,0 +1,107 @@
+#ifndef __ASM_SH_ATOMIC_LLSC_H
+#define __ASM_SH_ATOMIC_LLSC_H
+
+/*
+ * To get proper branch prediction for the main line, we must branch
+ * forward to code at the end of this object's .text section, then
+ * branch back to restart the operation.
+ */
+static inline void atomic_add(int i, atomic_t *v)
+{
+	unsigned long tmp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_add	\n"
+"	add	%1, %0				\n"
+"	movco.l	%0, @%2				\n"
+"	bf	1b				\n"
+	: "=&z" (tmp)
+	: "r" (i), "r" (&v->counter)
+	: "t");
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+	unsigned long tmp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_sub	\n"
+"	sub	%1, %0				\n"
+"	movco.l	%0, @%2				\n"
+"	bf	1b				\n"
+	: "=&z" (tmp)
+	: "r" (i), "r" (&v->counter)
+	: "t");
+}
+
+/*
+ * SH-4A note:
+ *
+ * We basically get atomic_xxx_return() for free compared with
+ * atomic_xxx(). movli.l/movco.l require r0 due to the instruction
+ * encoding, so the retval is automatically set without having to
+ * do any special work.
+ */
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+	unsigned long temp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_add_return	\n"
+"	add	%1, %0					\n"
+"	movco.l	%0, @%2					\n"
+"	bf	1b					\n"
+"	synco						\n"
+	: "=&z" (temp)
+	: "r" (i), "r" (&v->counter)
+	: "t");
+
+	return temp;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+	unsigned long temp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_sub_return	\n"
+"	sub	%1, %0					\n"
+"	movco.l	%0, @%2					\n"
+"	bf	1b					\n"
+"	synco						\n"
+	: "=&z" (temp)
+	: "r" (i), "r" (&v->counter)
+	: "t");
+
+	return temp;
+}
+
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
+{
+	unsigned long tmp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_clear_mask	\n"
+"	and	%1, %0					\n"
+"	movco.l	%0, @%2					\n"
+"	bf	1b					\n"
+	: "=&z" (tmp)
+	: "r" (~mask), "r" (&v->counter)
+	: "t");
+}
+
+static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
+{
+	unsigned long tmp;
+
+	__asm__ __volatile__ (
+"1:	movli.l @%2, %0		! atomic_set_mask	\n"
+"	or	%1, %0					\n"
+"	movco.l	%0, @%2					\n"
+"	bf	1b					\n"
+	: "=&z" (tmp)
+	: "r" (mask), "r" (&v->counter)
+	: "t");
+}
+
+#endif /* __ASM_SH_ATOMIC_LLSC_H */