From f5ce6edd22cff94e7b4a17f26cad43e60ae3d080 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 16 Nov 2015 17:41:02 +0000 Subject: [PATCH] tty: amba-pl011: switch to using relaxed IO accessors Using relaxed IO accessors allows GCC to better optimise this code as we eliminate the heavy memory barriers - for example, GCC can now cache the address of a register across a read-modify-write sequence, rather than reloading the base address, offset and access size flag. Signed-off-by: Russell King Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/amba-pl011.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 295f0be128f9..3b24aea343de 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -262,7 +262,7 @@ static unsigned int pl011_read(const struct uart_amba_port *uap, { void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); - return uap->access_32b ? readl(addr) : readw(addr); + return uap->access_32b ? readl_relaxed(addr) : readw_relaxed(addr); } static void pl011_write(unsigned int val, const struct uart_amba_port *uap, @@ -271,9 +271,9 @@ static void pl011_write(unsigned int val, const struct uart_amba_port *uap, void __iomem *addr = uap->port.membase + pl011_reg_to_offset(uap, reg); if (uap->access_32b) - writel(val, addr); + writel_relaxed(val, addr); else - writew(val, addr); + writew_relaxed(val, addr); } /* -- 2.45.2