sh: Provide optimized non-atomic bitops for SH-2A.

This ties in the new SH-2A 32-bit non-atomic bitops.

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

1 files changed, 142 insertions, 0 deletions

diff --git a/arch/sh/include/asm/bitops-op32.h b/arch/sh/include/asm/bitops-op32.h
new file mode 100644
index 000000000000..f0ae7e9218e0
--- /dev/null
+++ b/arch/sh/include/asm/bitops-op32.h
@@ -0,0 +1,142 @@
+#ifndef __ASM_SH_BITOPS_OP32_H
+#define __ASM_SH_BITOPS_OP32_H
+
+/*
+ * The bit modifying instructions on SH-2A are only capable of working
+ * with a 3-bit immediate, which signifies the shift position for the bit
+ * being worked on.
+ */
+#if defined(__BIG_ENDIAN)
+#define BITOP_LE_SWIZZLE        ((BITS_PER_LONG-1) & ~0x7)
+#define BYTE_NUMBER(nr)         ((nr ^ BITOP_LE_SWIZZLE) / BITS_PER_BYTE)
+#define BYTE_OFFSET(nr)         ((nr ^ BITOP_LE_SWIZZLE) % BITS_PER_BYTE)
+#else
+#define BYTE_NUMBER(nr)         ((nr) / BITS_PER_BYTE)
+#define BYTE_OFFSET(nr)         ((nr) % BITS_PER_BYTE)
+#endif
+
+#define IS_IMMEDIATE(nr)        (__builtin_constant_p(nr))
+
+static inline void __set_bit(int nr, volatile unsigned long *addr)
+{
+        if (IS_IMMEDIATE(nr)) {
+                __asm__ __volatile__ (
+                        "bset.b %1, @(%O2,%0)           ! __set_bit\n\t"
+                        : "+r" (addr)
+                        : "i" (BYTE_OFFSET(nr)), "i" (BYTE_NUMBER(nr))
+                        : "t", "memory"
+                );
+        } else {
+                unsigned long mask = BIT_MASK(nr);
+                unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+                *p |= mask;
+        }
+}
+
+static inline void __clear_bit(int nr, volatile unsigned long *addr)
+{
+        if (IS_IMMEDIATE(nr)) {
+                __asm__ __volatile__ (
+                        "bclr.b %1, @(%O2,%0)           ! __clear_bit\n\t"
+                        : "+r" (addr)
+                        : "i" (BYTE_OFFSET(nr)),
+                          "i" (BYTE_NUMBER(nr))
+                        : "t", "memory"
+                );
+        } else {
+                unsigned long mask = BIT_MASK(nr);
+                unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+                *p &= ~mask;
+        }
+}
+
+/**
+ * __change_bit - Toggle a bit in memory
+ * @nr: the bit to change
+ * @addr: the address to start counting from
+ *
+ * Unlike change_bit(), this function is non-atomic and may be reordered.
+ * If it's called on the same region of memory simultaneously, the effect
+ * may be that only one operation succeeds.
+ */
+static inline void __change_bit(int nr, volatile unsigned long *addr)
+{
+        if (IS_IMMEDIATE(nr)) {
+                __asm__ __volatile__ (
+                        "bxor.b %1, @(%O2,%0)           ! __change_bit\n\t"
+                        : "+r" (addr)
+                        : "i" (BYTE_OFFSET(nr)),
+                          "i" (BYTE_NUMBER(nr))
+                        : "t", "memory"
+                );
+        } else {
+                unsigned long mask = BIT_MASK(nr);
+                unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+                *p ^= mask;
+        }
+}
+
+/**
+ * __test_and_set_bit - Set a bit and return its old value
+ * @nr: Bit to set
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
+{
+        unsigned long mask = BIT_MASK(nr);
+        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+        unsigned long old = *p;
+
+        *p = old | mask;
+        return (old & mask) != 0;
+}
+
+/**
+ * __test_and_clear_bit - Clear a bit and return its old value
+ * @nr: Bit to clear
+ * @addr: Address to count from
+ *
+ * This operation is non-atomic and can be reordered.
+ * If two examples of this operation race, one can appear to succeed
+ * but actually fail.  You must protect multiple accesses with a lock.
+ */
+static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
+{
+        unsigned long mask = BIT_MASK(nr);
+        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+        unsigned long old = *p;
+
+        *p = old & ~mask;
+        return (old & mask) != 0;
+}
+
+/* WARNING: non atomic and it can be reordered! */
+static inline int __test_and_change_bit(int nr,
+                                            volatile unsigned long *addr)
+{
+        unsigned long mask = BIT_MASK(nr);
+        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+        unsigned long old = *p;
+
+        *p = old ^ mask;
+        return (old & mask) != 0;
+}
+
+/**
+ * test_bit - Determine whether a bit is set
+ * @nr: bit number to test
+ * @addr: Address to start counting from
+ */
+static inline int test_bit(int nr, const volatile unsigned long *addr)
+{
+        return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
+}
+
+#endif /* __ASM_SH_BITOPS_OP32_H */