sh: New atomic ops for SH-4A movli.l/movco.l

SH-4A implements LL/SC instructions, so we implement a simple
set of atomic operations using these.

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

diff --git a/include/asm-sh/atomic.h b/include/asm-sh/atomic.h
index 049eb2d..8bdc1ba 100644 (file)
--- a/include/asm-sh/atomic.h
+++ b/include/asm-sh/atomic.h
@@ -22,49 +22,110 @@ typedef struct { volatile int counter; } atomic_t;
  * 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)
+static inline void atomic_add(int i, atomic_t *v)
 {
+#ifdef CONFIG_CPU_SH4A
+       unsigned long tmp;
+
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_add    \n"
+"      add     %2, %0                          \n"
+"      movco.l %0, @%3                         \n"
+"      bf      1b                              \n"
+       : "=&z" (tmp), "=r" (&v->counter)
+       : "r" (i), "r" (&v->counter)
+       : "t");
+#else
        unsigned long flags;
 
        local_irq_save(flags);
        *(long *)v += i;
        local_irq_restore(flags);
+#endif
 }
 
-static __inline__ void atomic_sub(int i, atomic_t *v)
+static inline void atomic_sub(int i, atomic_t *v)
 {
+#ifdef CONFIG_CPU_SH4A
+       unsigned long tmp;
+
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_sub    \n"
+"      sub     %2, %0                          \n"
+"      movco.l %0, @%3                         \n"
+"      bf      1b                              \n"
+       : "=&z" (tmp), "=r" (&v->counter)
+       : "r" (i), "r" (&v->counter)
+       : "t");
+#else
        unsigned long flags;
 
        local_irq_save(flags);
        *(long *)v -= i;
        local_irq_restore(flags);
+#endif
 }
 
-static __inline__ int atomic_add_return(int i, atomic_t * v)
+/*
+ * 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, flags;
+       unsigned long temp;
+
+#ifdef CONFIG_CPU_SH4A
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_add_return     \n"
+"      add     %2, %0                                  \n"
+"      movco.l %0, @%3                                 \n"
+"      bf      1b                                      \n"
+"      synco                                           \n"
+       : "=&z" (temp), "=r" (&v->counter)
+       : "r" (i), "r" (&v->counter)
+       : "t");
+#else
+       unsigned long flags;
 
        local_irq_save(flags);
        temp = *(long *)v;
        temp += i;
        *(long *)v = temp;
        local_irq_restore(flags);
+#endif
 
        return temp;
 }
 
 #define atomic_add_negative(a, v)      (atomic_add_return((a), (v)) < 0)
 
-static __inline__ int atomic_sub_return(int i, atomic_t * v)
+static inline int atomic_sub_return(int i, atomic_t *v)
 {
-       unsigned long temp, flags;
+       unsigned long temp;
+
+#ifdef CONFIG_CPU_SH4A
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_sub_return     \n"
+"      sub     %2, %0                                  \n"
+"      movco.l %0, @%3                                 \n"
+"      bf      1b                                      \n"
+"      synco                                           \n"
+       : "=&z" (temp), "=r" (&v->counter)
+       : "r" (i), "r" (&v->counter)
+       : "t");
+#else
+       unsigned long flags;
 
        local_irq_save(flags);
        temp = *(long *)v;
        temp -= i;
        *(long *)v = temp;
        local_irq_restore(flags);
+#endif
 
        return temp;
 }
@@ -119,22 +180,48 @@ static inline int atomic_add_unless(atomic_t *v, int a, int u)
 }
 #define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
 
-static __inline__ void atomic_clear_mask(unsigned int mask, atomic_t *v)
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
 {
+#ifdef CONFIG_CPU_SH4A
+       unsigned long tmp;
+
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_clear_mask     \n"
+"      and     %2, %0                                  \n"
+"      movco.l %0, @%3                                 \n"
+"      bf      1b                                      \n"
+       : "=&z" (tmp), "=r" (&v->counter)
+       : "r" (~mask), "r" (&v->counter)
+       : "t");
+#else
        unsigned long flags;
 
        local_irq_save(flags);
        *(long *)v &= ~mask;
        local_irq_restore(flags);
+#endif
 }
 
-static __inline__ void atomic_set_mask(unsigned int mask, atomic_t *v)
+static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
 {
+#ifdef CONFIG_CPU_SH4A
+       unsigned long tmp;
+
+       __asm__ __volatile__ (
+"1:    movli.l @%3, %0         ! atomic_set_mask       \n"
+"      or      %2, %0                                  \n"
+"      movco.l %0, @%3                                 \n"
+"      bf      1b                                      \n"
+       : "=&z" (tmp), "=r" (&v->counter)
+       : "r" (mask), "r" (&v->counter)
+       : "t");
+#else
        unsigned long flags;
 
        local_irq_save(flags);
        *(long *)v |= mask;
        local_irq_restore(flags);
+#endif
 }
 
 /* Atomic operations are already serializing on SH */