[Linux-kernel] [PATCH 12/13] mmc: atmel-mci: use endian agnostic IO

[Ben Hutchings]

On Wed, 2015-03-18 at 15:53 +0000, Ben Dooks wrote:
> Change the __raw IO functions to endian agnostic relaxed ones to allow
> the driver to function on big endian ARM systems.
> 
> Signed-off-by: Ben Dooks <ben.dooks at codethink.co.uk>
> --
> CC: Ludovic Desroches <ludovic.desroches at atmel.com>
> CC: Chris Ball <chris at printf.net>
> CC: Ulf Hansson <ulf.hansson at linaro.org>
> CC: linux-mmc at vger.kernel.org
> ---
>  drivers/mmc/host/atmel-mci-regs.h | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/atmel-mci-regs.h b/drivers/mmc/host/atmel-mci-regs.h
> index c97001e..711bb53 100644
> --- a/drivers/mmc/host/atmel-mci-regs.h
> +++ b/drivers/mmc/host/atmel-mci-regs.h
> @@ -135,10 +135,17 @@
>  #define ATMCI_REGS_SIZE		0x100
>  
>  /* Register access macros */
> -#define atmci_readl(port,reg)				\
> +#ifdef CONFIG_AVR32
> +#define atmci_readl(port,reg)			\
>  	__raw_readl((port)->regs + reg)
>  #define atmci_writel(port,reg,value)			\
>  	__raw_writel((value), (port)->regs + reg)
> +#else
> +#define atmci_readl(port,reg)			\
> +	readl_relaxed((port)->regs + reg)
> +#define atmci_writel(port,reg,value)			\
> +	writel_relaxed((value), (port)->regs + reg)
> +#endif

This pattern is repeated in a lot of drivers; is it worth defining
atmel_{read,write}l_relaxed() in a common header?

#ifdef CONFIG_AVR32

/* CPU and peripherals are both big-endian, so don't byte-swap */
#define atmel_readl_relaxed(addr)		__raw_readl(addr)
#define atmel_writel_relaxed(value, addr)	__raw_writel(value, addr)

#else

/* Peripherals are little-endian, so byte-swap if CPU isn't */
#define atmel_readl_relaxed(addr)		readl_relaxed(addr)
#define atmel_writel_relaxed(value, addr)	writel_relaxed(value, addr)

#endif

Ben.

>  /* On AVR chips the Peripheral DMA Controller is not connected to MCI. */
>  #ifdef CONFIG_AVR32