Re: [PATCH v11 17/19] serial: asc: Adopt readl_/writel_relaxed()

[Maxime Coquelin]

Hi Daniel,

On 09/02/2014 03:00 PM, 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@xxxxxxxxxx>
> Cc: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxx>
> Cc: Maxime Coquelin <maxime.coquelin@xxxxxx>
> Cc: Patrice Chotard <patrice.chotard@xxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Jiri Slaby <jslaby@xxxxxxx>
> Cc: kernel@xxxxxxxxxxx
> Cc: linux-serial@xxxxxxxxxxxxxxx
> ---
>   drivers/tty/serial/Kconfig  | 2 +-
>   drivers/tty/serial/st-asc.c | 4 ++--
>   2 files changed, 3 insertions(+), 3 deletions(-)



You can add my:
Acked-by: Maxime Coquelin <maxime.coquelin@xxxxxx>

thanks!
Maxime

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