| Date | Tue, 2 Sep 2014 15:55:19 +0200 | From | Maxime Coquelin <> | Subject | Re: [PATCH v11 17/19] serial: asc: Adopt readl_/writel_relaxed() |
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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@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 > --- > 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@st.com>
thanks! Maxime
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