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From: Arnd Bergmann <arnd@arndb.de>
To: Srinivas KANDAGATLA <srinivas.kandagatla@st.com>
Subject: Re: [PATCH v3 02/10] clocksource:arm_global_timer: Add ARM global timer support.
Date: Thu, 20 Jun 2013 21:02:30 +0200
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Cc: linux-arm-kernel@lists.infradead.org, Rob Landley <rob@landley.net>,
        Grant Likely <grant.likely@linaro.org>,
        Rob Herring <rob.herring@calxeda.com>,
        Russell King <linux@arm.linux.org.uk>,
        Stuart Menefy <stuart.menefy@st.com>,
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        Thomas Gleixner <tglx@linutronix.de>,
        Linus Walleij <linus.walleij@linaro.org>,
        "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
        Jiri Slaby <jslaby@suse.cz>, linux-doc@vger.kernel.org,
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On Thursday 20 June 2013, Srinivas KANDAGATLA wrote:
> +static u64 gt_counter_read(void)
> +{
> +       u64 counter;
> +       u32 lower;
> +       u32 upper, old_upper;
> +
> +       upper = __raw_readl(gt_base + GT_COUNTER1);
> +       do {
> +               old_upper = upper;
> +               lower = __raw_readl(gt_base + GT_COUNTER0);
> +               upper = __raw_readl(gt_base + GT_COUNTER1);
> +       } while (upper != old_upper);
> +
> +       counter = upper;
> +       counter <<= 32;
> +       counter |= lower;
> +       return counter;
> +}

Please replace __raw_readl etc with the non-__raw variants
throughout the code.

The __raw accessors are not endian safe and are not meant
for device drivers. If you are worried about latency from
extra barriers, use readl_relaxed().

	Arnd