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, 169 insertions, 0 deletions

diff --git a/include/asm-sh/atomic-grb.h b/include/asm-sh/atomic-grb.h
new file mode 100644
index 000000000000..4c5b7dbfcedb
--- /dev/null
+++ b/include/asm-sh/atomic-grb.h
@@ -0,0 +1,169 @@
+#ifndef __ASM_SH_ATOMIC_GRB_H
+#define __ASM_SH_ATOMIC_GRB_H
+
+static inline void atomic_add(int i, atomic_t *v)
+{
+	int tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov    r15,   r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   add     %2,   %0      \n\t" /* add */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (i)
+		: "memory" , "r0", "r1");
+}
+
+static inline void atomic_sub(int i, atomic_t *v)
+{
+	int tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov     r15,  r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   sub     %2,   %0      \n\t" /* sub */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (i)
+		: "memory" , "r0", "r1");
+}
+
+static inline int atomic_add_return(int i, atomic_t *v)
+{
+	int tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov    r15,   r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   add     %2,   %0      \n\t" /* add */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (i)
+		: "memory" , "r0", "r1");
+
+	return tmp;
+}
+
+static inline int atomic_sub_return(int i, atomic_t *v)
+{
+	int tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov    r15,   r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   sub     %2,   %0      \n\t" /* sub */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (i)
+		: "memory", "r0", "r1");
+
+	return tmp;
+}
+
+static inline void atomic_clear_mask(unsigned int mask, atomic_t *v)
+{
+	int tmp;
+	unsigned int _mask = ~mask;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov    r15,   r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   and     %2,   %0      \n\t" /* add */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (_mask)
+		: "memory" , "r0", "r1");
+}
+
+static inline void atomic_set_mask(unsigned int mask, atomic_t *v)
+{
+	int tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2              \n\t"
+		"   mova    1f,   r0      \n\t" /* r0 = end point */
+		"   mov    r15,   r1      \n\t" /* r1 = saved sp */
+		"   mov    #-6,   r15     \n\t" /* LOGIN: r15 = size */
+		"   mov.l  @%1,   %0      \n\t" /* load  old value */
+		"   or      %2,   %0      \n\t" /* or */
+		"   mov.l   %0,   @%1     \n\t" /* store new value */
+		"1: mov     r1,   r15     \n\t" /* LOGOUT */
+		: "=&r" (tmp),
+		  "+r"  (v)
+		: "r"   (mask)
+		: "memory" , "r0", "r1");
+}
+
+static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
+{
+	int ret;
+
+	__asm__ __volatile__ (
+		"   .align 2		\n\t"
+		"   mova     1f,  r0	\n\t"
+		"   nop			\n\t"
+		"   mov     r15,  r1	\n\t"
+		"   mov    #-8,  r15	\n\t"
+		"   mov.l   @%1,  %0	\n\t"
+		"   cmp/eq   %2,  %0	\n\t"
+		"   bf	     1f		\n\t"
+		"   mov.l    %3, @%1	\n\t"
+		"1: mov      r1,  r15	\n\t"
+		: "=&r" (ret)
+		: "r" (v), "r" (old), "r" (new)
+		: "memory" , "r0", "r1" , "t");
+
+	return ret;
+}
+
+static inline int atomic_add_unless(atomic_t *v, int a, int u)
+{
+	int ret;
+	unsigned long tmp;
+
+	__asm__ __volatile__ (
+		"   .align 2		\n\t"
+		"   mova    1f,   r0	\n\t"
+		"   nop			\n\t"
+		"   mov    r15,   r1	\n\t"
+		"   mov    #-12,  r15	\n\t"
+		"   mov.l  @%2,   %1	\n\t"
+		"   mov	    %1,   %0    \n\t"
+		"   cmp/eq  %4,   %0	\n\t"
+		"   bt/s    1f		\n\t"
+		"    add    %3,   %1	\n\t"
+		"   mov.l   %1,  @%2	\n\t"
+		"1: mov     r1,   r15	\n\t"
+		: "=&r" (ret), "=&r" (tmp)
+		: "r" (v), "r" (a), "r" (u)
+		: "memory" , "r0", "r1" , "t");
+
+	return ret != u;
+}
+#endif /* __ASM_SH_ATOMIC_GRB_H */