[PATCH v2 07/23] openrisc: add atomic bitops

From: Stafford Horne
Date: Fri Feb 03 2017 - 10:55:45 EST


From: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>

This utilize the load-link/store-conditional l.lwa and l.swa
instructions to implement the atomic bitops.
When those instructions are not available emulation is provided.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
[shorne@xxxxxxxxx: remove OPENRISC_HAVE_INST_LWA_SWA config suggesed by
Alan Cox https://lkml.org/lkml/2014/7/23/666, implement
test_and_change_bit]
Signed-off-by: Stafford Horne <shorne@xxxxxxxxx>
---
arch/openrisc/include/asm/bitops.h | 2 +-
arch/openrisc/include/asm/bitops/atomic.h | 123 ++++++++++++++++++++++++++++++
2 files changed, 124 insertions(+), 1 deletion(-)
create mode 100644 arch/openrisc/include/asm/bitops/atomic.h

diff --git a/arch/openrisc/include/asm/bitops.h b/arch/openrisc/include/asm/bitops.h
index 3003cda..689f568 100644
--- a/arch/openrisc/include/asm/bitops.h
+++ b/arch/openrisc/include/asm/bitops.h
@@ -45,7 +45,7 @@
#include <asm-generic/bitops/hweight.h>
#include <asm-generic/bitops/lock.h>

-#include <asm-generic/bitops/atomic.h>
+#include <asm/bitops/atomic.h>
#include <asm-generic/bitops/non-atomic.h>
#include <asm-generic/bitops/le.h>
#include <asm-generic/bitops/ext2-atomic.h>
diff --git a/arch/openrisc/include/asm/bitops/atomic.h b/arch/openrisc/include/asm/bitops/atomic.h
new file mode 100644
index 0000000..35fb85f
--- /dev/null
+++ b/arch/openrisc/include/asm/bitops/atomic.h
@@ -0,0 +1,123 @@
+/*
+ * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@xxxxxxxxxxxxx>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#ifndef __ASM_OPENRISC_BITOPS_ATOMIC_H
+#define __ASM_OPENRISC_BITOPS_ATOMIC_H
+
+static inline void 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 tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%1) \n"
+ " l.or %0,%0,%2 \n"
+ " l.swa 0(%1),%0 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(tmp)
+ : "r"(p), "r"(mask)
+ : "cc", "memory");
+}
+
+static inline void 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 tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%1) \n"
+ " l.and %0,%0,%2 \n"
+ " l.swa 0(%1),%0 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(tmp)
+ : "r"(p), "r"(~mask)
+ : "cc", "memory");
+}
+
+static inline void 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 tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%1) \n"
+ " l.xor %0,%0,%2 \n"
+ " l.swa 0(%1),%0 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(tmp)
+ : "r"(p), "r"(mask)
+ : "cc", "memory");
+}
+
+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;
+ unsigned long tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%2) \n"
+ " l.or %1,%0,%3 \n"
+ " l.swa 0(%2),%1 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(old), "=&r"(tmp)
+ : "r"(p), "r"(mask)
+ : "cc", "memory");
+
+ return (old & mask) != 0;
+}
+
+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;
+ unsigned long tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%2) \n"
+ " l.and %1,%0,%3 \n"
+ " l.swa 0(%2),%1 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(old), "=&r"(tmp)
+ : "r"(p), "r"(~mask)
+ : "cc", "memory");
+
+ return (old & mask) != 0;
+}
+
+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;
+ unsigned long tmp;
+
+ __asm__ __volatile__(
+ "1: l.lwa %0,0(%2) \n"
+ " l.xor %1,%0,%3 \n"
+ " l.swa 0(%2),%1 \n"
+ " l.bnf 1b \n"
+ " l.nop \n"
+ : "=&r"(old), "=&r"(tmp)
+ : "r"(p), "r"(mask)
+ : "cc", "memory");
+
+ return (old & mask) != 0;
+}
+
+#endif /* __ASM_OPENRISC_BITOPS_ATOMIC_H */
--
2.9.3