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From: Jisheng Zhang <jszhang@marvell.com>
To: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: use {readl|writel}_relaxed instead of readl/writel in i2c-designware-core ?
Date: Fri, 14 Feb 2014 15:54:38 +0800	[thread overview]
Message-ID: <20140214155438.4f749a79@xhacker> (raw)

Hi all,

The writel/readl is too expensive especially on Cortex A9 w/ outer L2 cache. This
introduce i2c read/write error on Marvell Berlin SoCs when there are L2 cache
maintenance operations at the same time.

In our internal berlin bsp, we just replaced readl/writel with the relaxed
version. But AFAIK, the "relaxed" version doesn't exist on all architectures. How
to handle this issue? 

Any suggestions are appreciated.

Thanks in advance,
Jisheng

WARNING: multiple messages have this Message-ID (diff)
From: jszhang@marvell.com (Jisheng Zhang)
To: linux-arm-kernel@lists.infradead.org
Subject: use {readl|writel}_relaxed instead of readl/writel in i2c-designware-core ?
Date: Fri, 14 Feb 2014 15:54:38 +0800	[thread overview]
Message-ID: <20140214155438.4f749a79@xhacker> (raw)

Hi all,

The writel/readl is too expensive especially on Cortex A9 w/ outer L2 cache. This
introduce i2c read/write error on Marvell Berlin SoCs when there are L2 cache
maintenance operations at the same time.

In our internal berlin bsp, we just replaced readl/writel with the relaxed
version. But AFAIK, the "relaxed" version doesn't exist on all architectures. How
to handle this issue? 

Any suggestions are appreciated.

Thanks in advance,
Jisheng

             reply	other threads:[~2014-02-14  7:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-02-14  7:54 Jisheng Zhang [this message]
2014-02-14  7:54 ` use {readl|writel}_relaxed instead of readl/writel in i2c-designware-core ? Jisheng Zhang
2014-02-14  7:54 ` Jisheng Zhang
2014-02-14  9:09 ` Arnd Bergmann
2014-02-14  9:09   ` Arnd Bergmann
2014-02-14 11:14   ` Jisheng Zhang
2014-02-14 11:14     ` Jisheng Zhang
2014-02-14 11:14     ` Jisheng Zhang

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