From: Lada Trimasova <Lada.Trimasova@synopsys.com>
To: linux-snps-arc@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
Lada Trimasova <Lada.Trimasova@synopsys.com>,
Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: [PATCH] arc: use little endian accesses
Date: Wed, 9 Mar 2016 20:21:04 +0300 [thread overview]
Message-ID: <1457544064-16167-1-git-send-email-ltrimas@synopsys.com> (raw)
Memory access primitives should use cpu_to_le16, cpu_to_le32, le16_to_cpu
and le32_to_cpu because it is not really guaranteed that drivers handles
any ordering themselves.
For example, serial port driver doesn't work when kernel is build for
arc big endian architecture.
Signed-off-by: Lada Trimasova <ltrimas@synopsys.com>
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
---
arch/arc/include/asm/io.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/arc/include/asm/io.h b/arch/arc/include/asm/io.h
index 694ece8..0b3d5ea 100644
--- a/arch/arc/include/asm/io.h
+++ b/arch/arc/include/asm/io.h
@@ -129,15 +129,17 @@ static inline void __raw_writel(u32 w, volatile void __iomem *addr)
#define writel(v,c) ({ __iowmb(); writel_relaxed(v,c); })
/*
- * Relaxed API for drivers which can handle any ordering themselves
+ * This are defined to perform little endian accesses
*/
#define readb_relaxed(c) __raw_readb(c)
-#define readw_relaxed(c) __raw_readw(c)
-#define readl_relaxed(c) __raw_readl(c)
+#define readw_relaxed(c) ({ u16 __r = le16_to_cpu((__force __le16) \
+ __raw_readw(c)); __r; })
+#define readl_relaxed(c) ({ u32 __r = le32_to_cpu((__force __le32) \
+ __raw_readl(c)); __r; })
#define writeb_relaxed(v,c) __raw_writeb(v,c)
-#define writew_relaxed(v,c) __raw_writew(v,c)
-#define writel_relaxed(v,c) __raw_writel(v,c)
+#define writew_relaxed(v,c) __raw_writew((__force u16) cpu_to_le16(v),c)
+#define writel_relaxed(v,c) __raw_writel((__force u32) cpu_to_le32(v),c)
#include <asm-generic/io.h>
--
2.5.0
next reply other threads:[~2016-03-09 17:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 17:21 Lada Trimasova [this message]
2016-03-10 5:05 ` [PATCH] arc: use little endian accesses Vineet Gupta
2016-03-10 5:19 ` Vineet Gupta
2016-03-10 5:19 ` Vineet Gupta
2016-03-10 7:44 ` Alexey Brodkin
2016-03-10 9:55 ` Vineet Gupta
2016-03-10 18:57 ` Lada Trimasova
2016-03-10 18:57 ` Lada Trimasova
2016-03-10 19:23 ` Arnd Bergmann
2016-03-11 12:44 ` Vineet Gupta
2016-03-12 4:20 ` Vineet Gupta
2016-03-12 4:20 ` Vineet Gupta
2016-03-11 5:07 ` Noam Camus
2016-03-11 5:07 ` Noam Camus
2016-03-10 7:45 ` Arnd Bergmann
2016-03-10 7:45 ` Arnd Bergmann
2016-03-11 5:18 ` Vineet Gupta
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