sh: GUSA atomic rollback support.

This implements kernel-level atomic rollback built on top of gUSA,
as an alternative non-IRQ based atomicity method. This is generally
a faster method for platforms that are lacking the LL/SC pairs that
SH-4A and later use, and is only supportable on legacy cores.

Signed-off-by: Stuart Menefy <stuart.menefy@st.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 91 insertions, 0 deletions

diff --git a/include/asm-sh/bitops-irq.h b/include/asm-sh/bitops-irq.h
new file mode 100644
index 000000000000..653a12750584
--- /dev/null
+++ b/include/asm-sh/bitops-irq.h
@@ -0,0 +1,91 @@
+#ifndef __ASM_SH_BITOPS_IRQ_H
+#define __ASM_SH_BITOPS_IRQ_H
+
+static inline void set_bit(int nr, volatile void *addr)
+{
+        int     mask;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        *a |= mask;
+        local_irq_restore(flags);
+}
+
+static inline void clear_bit(int nr, volatile void *addr)
+{
+        int     mask;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        *a &= ~mask;
+        local_irq_restore(flags);
+}
+
+static inline void change_bit(int nr, volatile void *addr)
+{
+        int     mask;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        *a ^= mask;
+        local_irq_restore(flags);
+}
+
+static inline int test_and_set_bit(int nr, volatile void *addr)
+{
+        int     mask, retval;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        retval = (mask & *a) != 0;
+        *a |= mask;
+        local_irq_restore(flags);
+
+        return retval;
+}
+
+static inline int test_and_clear_bit(int nr, volatile void *addr)
+{
+        int     mask, retval;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        retval = (mask & *a) != 0;
+        *a &= ~mask;
+        local_irq_restore(flags);
+
+        return retval;
+}
+
+static inline int test_and_change_bit(int nr, volatile void *addr)
+{
+        int     mask, retval;
+        volatile unsigned int *a = addr;
+        unsigned long flags;
+
+        a += nr >> 5;
+        mask = 1 << (nr & 0x1f);
+        local_irq_save(flags);
+        retval = (mask & *a) != 0;
+        *a ^= mask;
+        local_irq_restore(flags);
+
+        return retval;
+}
+
+#endif /* __ASM_SH_BITOPS_IRQ_H */