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SubjectRe: [STLinux Kernel] [PATCH v11 17/19] serial: asc: Adopt readl_/writel_relaxed()
On Tue, 02 Sep 2014, Daniel Thompson wrote:

> The architectures where this peripheral exists (ARM and SH) have expensive
> implementations of writel(), reliant on spin locks and explicit L2 cache
> management. These architectures provide a cheaper writel_relaxed() which
> is much better suited to peripherals that do not perform DMA. The
> situation with readl()/readl_relaxed()is similar although less acute.
>
> This driver does not use DMA and will be more power efficient and more
> robust (due to absense of spin locks during console I/O) if it uses the
> relaxed variants.
>
> This change means the driver is no longer portable and therefore no
> longer suitable for compile testing.
>
> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
> Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com>
> Cc: Maxime Coquelin <maxime.coquelin@st.com>
> Cc: Patrice Chotard <patrice.chotard@st.com>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Jiri Slaby <jslaby@suse.cz>
> Cc: kernel@stlinux.com
> Cc: linux-serial@vger.kernel.org

Acked-by: Peter Griffin <peter.griffin@linaro.org>



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