[U-Boot] [PATCH] net: configure DWMAC DMA by default AXI burst length

[Joe Hershberger]

On Tue, Jan 27, 2015 at 9:24 PM, Sonic Zhang <sonic.adi at gmail.com> wrote:
>
> Hi Joe,
>
> On Wed, Jan 28, 2015 at 4:43 AM, Joe Hershberger
> <joe.hershberger at gmail.com> wrote:
> > On Mon, Jan 26, 2015 at 8:54 PM, <sonic.adi at gmail.com> wrote:
> >>
> >> From: Sonic Zhang <sonic.zhang at analog.com>
> >>
> >> Board can define its own AXI burst length to improve DWMAC DMA
> >> performance.
> >>
> >> Signed-off-by: Sonic Zhang <sonic.zhang at analog.com>
> >> ---
> >>
> >>  drivers/net/designware.c |    2 ++
> >>  drivers/net/designware.h |    5 +++++
> >>  2 files changed, 7 insertions(+)
> >>
> >> diff --git a/drivers/net/designware.c b/drivers/net/designware.c
> >> index 9ded895..d8d6792 100644
> >> --- a/drivers/net/designware.c
> >> +++ b/drivers/net/designware.c
> >> @@ -256,6 +256,8 @@ static int dw_eth_init(struct eth_device *dev, bd_t
> >> *bis)
> >>
> >>         writel(readl(&dma_p->opmode) | RXSTART | TXSTART,
&dma_p->opmode);
> >>
> > This should probably include:
> > +#if CONFIG_DW_AXI_BURST_LEN
> > so that this register is only accessed if configured.
>
> CONFIG_DW_AXI_BURST_LEN is always defined in designware.h in the same
patch.
>
> +/* Default AXI BUS Burst length */
> +#ifndef CONFIG_DW_AXI_BURST_LEN
> +#define CONFIG_DW_AXI_BURST_LEN 0
> +#endif
> +

Yes, I saw that... sorry I wasn't clear.  I meant don't we want to avoid
the write (preserving existing behavior) instead of ensuring that it is
set, and still adding a register write that is (presumably) a NOP?

-Joe