[U-Boot] [PATCH v2] net/designware: Consecutive writes to the same register to be avoided

[Amit Virdi <amit.virdi@st.com>]

On 6/8/2012 8:56 PM, Dinh Nguyen wrote:
> This commit is an add-on to f6c4191f. There are a few registers where
> consecutive writes to the same location should be avoided or have a delay.
>
> According to Synopsys, here is a list of the registers and bit(s) where
> consecutive writes should be avoided or a delay is required:
>
> DMA Registers:
> Register 0        Bit 7
> Register 6        All bits except for 24, 16-13, 2-1.
>
> GMAC Registers:
> Registers 0-3     All bits
> Registers 6-7     All bits
> Register 10       All bits
> Register 11       All bits except for 5-6.
> Registers 16-47   All bits
> Register 48       All bits except for 18-16, 14.
> Register 448      Bit 4.
> Register 459      Bits 0-3.
>
> Reviewd-by: Matthew Gerlach<mgerlach@altera.com>
> Signed-off-by: Dinh Nguyen<dinguyen@altera.com>
> ---
>   drivers/net/designware.c |    4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/designware.c b/drivers/net/designware.c
> index e8e669b..980b92f 100644
> --- a/drivers/net/designware.c
> +++ b/drivers/net/designware.c
> @@ -163,8 +163,8 @@ static int dw_eth_init(struct eth_device *dev, bd_t *bis)
>   	writel(FIXEDBURST | PRIORXTX_41 | BURST_16,
>   			&dma_p->busmode);
>
> -	writel(FLUSHTXFIFO | readl(&dma_p->opmode),&dma_p->opmode);
> -	writel(STOREFORWARD | TXSECONDFRAME,&dma_p->opmode);
> +	writel(readl(&dma_p->opmode) | FLUSHTXFIFO | STOREFORWARD |
> +		TXSECONDFRAME,&dma_p->opmode);
>
>   	conf = FRAMEBURSTENABLE | DISABLERXOWN;
>

Acked-by: Amit Virdi <amit.virdi@st.com>