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[01/13] powerpc: Add simple cache inhibited MMIO accessors

Message ID 1471584957-21484-2-git-send-email-paulus@ozlabs.org
State Accepted
Headers show

Commit Message

Paul Mackerras Aug. 19, 2016, 5:35 a.m. UTC 
From: Suresh Warrier <warrier@linux.vnet.ibm.com>

Add simple cache inhibited accessors for memory mapped I/O.
Unlike the accessors built from the DEF_MMIO_* macros, these
don't include any hardware memory barriers, callers need to
manage memory barriers on their own. These can only be called
in hypervisor real mode.

Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
[paulus@ozlabs.org - added line to comment]
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---
 arch/powerpc/include/asm/io.h | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)
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Patch

diff --git a/arch/powerpc/include/asm/io.h b/arch/powerpc/include/asm/io.h
index 2fd1690..f6fda84 100644
--- a/arch/powerpc/include/asm/io.h
+++ b/arch/powerpc/include/asm/io.h
@@ -241,6 +241,35 @@  static inline void out_be64(volatile u64 __iomem *addr, u64 val)
 #endif
 #endif /* __powerpc64__ */
 
+
+/*
+ * Simple Cache inhibited accessors
+ * Unlike the DEF_MMIO_* macros, these don't include any h/w memory
+ * barriers, callers need to manage memory barriers on their own.
+ * These can only be used in hypervisor real mode.
+ */
+
+static inline u32 _lwzcix(unsigned long addr)
+{
+	u32 ret;
+
+	__asm__ __volatile__("lwzcix %0,0, %1"
+			     : "=r" (ret) : "r" (addr) : "memory");
+	return ret;
+}
+
+static inline void _stbcix(u64 addr, u8 val)
+{
+	__asm__ __volatile__("stbcix %0,0,%1"
+		: : "r" (val), "r" (addr) : "memory");
+}
+
+static inline void _stwcix(u64 addr, u32 val)
+{
+	__asm__ __volatile__("stwcix %0,0,%1"
+		: : "r" (val), "r" (addr) : "memory");
+}
+
 /*
  * Low level IO stream instructions are defined out of line for now
  */