[U-Boot] [PATCH 09/14] sunxi: dram: Add a helper function 'mctl_get_number_of_lanes'

[Ian Campbell]

On Fri, 2014-07-18 at 19:23 +0300, Siarhei Siamashka wrote:
> It is going to be useful in more than one place.
> 
> Signed-off-by: Siarhei Siamashka <siarhei.siamashka at gmail.com>
> ---
>  arch/arm/cpu/armv7/sunxi/dram.c | 30 +++++++++++++++++++-----------
>  1 file changed, 19 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/arm/cpu/armv7/sunxi/dram.c b/arch/arm/cpu/armv7/sunxi/dram.c
> index 18a5c3b..49d1770 100644
> --- a/arch/arm/cpu/armv7/sunxi/dram.c
> +++ b/arch/arm/cpu/armv7/sunxi/dram.c
> @@ -115,23 +115,31 @@ static void mctl_enable_dll0(u32 phase)
>  	udelay(22);
>  }
>  
> +/* Get the number of DDR byte lanes */
> +static u32 mctl_get_number_of_lanes(void)
> +{
> +	struct sunxi_dram_reg *dram = (struct sunxi_dram_reg *)SUNXI_DRAMC_BASE;
> +	switch (readl(&dram->dcr) & DRAM_DCR_BUS_WIDTH_MASK) {
> +	case DRAM_DCR_BUS_WIDTH(DRAM_DCR_BUS_WIDTH_32BIT):
> +		return 4;
> +	case DRAM_DCR_BUS_WIDTH(DRAM_DCR_BUS_WIDTH_16BIT):
> +		return 2;
> +	default:
> +		return 1;
> +	}
> +}
> +
>  /*
>   * Note: This differs from pm/standby in that it checks the bus width
>   */
>  static void mctl_enable_dllx(u32 phase)
>  {
>  	struct sunxi_dram_reg *dram = (struct sunxi_dram_reg *)SUNXI_DRAMC_BASE;
> -	u32 i, n, bus_width;
> -
> -	bus_width = readl(&dram->dcr);
> +	u32 i, number_of_lanes;
>  
> -	if ((bus_width & DRAM_DCR_BUS_WIDTH_MASK) ==
> -	    DRAM_DCR_BUS_WIDTH(DRAM_DCR_BUS_WIDTH_32BIT))
> -		n = DRAM_DCR_NR_DLLCR_32BIT;
> -	else
> -		n = DRAM_DCR_NR_DLLCR_16BIT;

Either DRAM_DCR_NR_DLLCR_??BIT are obsolete now and should be removed or
they should be be adjusted and used in the new function.

ISTM they don't add much so removing would be fine by me.

> +	number_of_lanes = mctl_get_number_of_lanes();

There is a subtle functional change here since number_of_lanes can be 1
whereas n could never have been 2. Is that intended/ok? Please mention
in the commit message.

Ian.