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serial: asc: Adopt readl_/writel_relaxed()
The architectures supported by this driver, 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 absence of spin locks during console I/O) if it uses the relaxed variants. The driver supports COMPILE_TEST and therefore falls back to writel() when writel_relaxed() does not exist. Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Acked-by: Srinivas Kandagatla <srinivas.kandagatla@gmail.com> Cc: Maxime Coquelin <maxime.coquelin@st.com> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: kernel@stlinux.com Cc: linux-serial@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -151,12 +151,16 @@ static inline struct asc_port *to_asc_port(struct uart_port *port)
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static inline u32 asc_in(struct uart_port *port, u32 offset)
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{
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return readl(port->membase + offset);
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return readl_relaxed(port->membase + offset);
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}
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static inline void asc_out(struct uart_port *port, u32 offset, u32 value)
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{
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#ifdef writel_relaxed
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writel_relaxed(value, port->membase + offset);
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#else
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writel(value, port->membase + offset);
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#endif
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}
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/*
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