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From: Arnd Bergmann <arnd@arndb.de>
To: linux-arm-kernel@lists.infradead.org
Cc: Hoan Tran <hotran@apm.com>, linux-hwmon@vger.kernel.org,
        Jonathan Corbet <corbet@lwn.net>, Jean Delvare <jdelvare@suse.com>,
        Ashwin Chaugule <ashwin.chaugule@linaro.org>,
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        Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH] hwmon: xgene: access mailbox as RAM
Date: Fri, 09 Sep 2016 22:50:43 +0200
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On Friday, September 9, 2016 1:43:17 PM CEST Hoan Tran wrote:
> 
> > * Are you sure you don't need any smp_rmb()/smp_wmb() barriers
> > between the accesses?
> 
> No, we don't need a strict read/write during access PCC subspace. Just
> make sure all access is committed before PCC send message to the
> platform which done by PCC mailbox driver.
> 

Ok, got it. The PCC mailbox driver presumably uses writel() to
send the message, and that implies the necessary barrier
(unlike writel_relaxed), right?

	Arnd