Linux-arch Archive on lore.kernel.org
 help / color / Atom feed
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
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

             reply index

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 ` 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1457544064-16167-1-git-send-email-ltrimas@synopsys.com \
    --to=lada.trimasova@synopsys.com \
    --cc=Alexey.Brodkin@synopsys.com \
    --cc=Vineet.Gupta1@synopsys.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-snps-arc@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-arch Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arch/0 linux-arch/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arch linux-arch/ https://lore.kernel.org/linux-arch \
		linux-arch@vger.kernel.org
	public-inbox-index linux-arch

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-arch


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git