Re: [PATCH] net: macb: fix endian code for avr32

From: Arun Chandran
Date: Wed Mar 18 2015 - 09:16:46 EST


On Wed, Mar 18, 2015 at 4:27 PM, Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> wrote:
>
> [note this has yet to be compile tested on avr32]
>
> The changes to run the macb driver in 29af05aeb98e ("net: macb:

Yes I mistakenly thought zynq board was the first to run it in
BIG endian mode.

> Add big endian CPU support") to support big endian operation on
> ARM may not work on AVR32 which already is naturally big endian
> architecture (and the driver already works here).
>
> In this case the readl/writel relaxed will do the opposite of __raw
> accesors which arleady work. Add an indirection of cdneth_ prefixed
> accesors which are changed as necessary. Also do not issue the DMA
> descritpor endian fetch configuration for AVR32.
>
> From discussions with Arnd Bergman, the following fix changes the use
> of readl_relaxed and writel_relaxed with a version that can be put
> back to __raw_readl/__raw_writel for the CONFIG_AVR32 case (and also
> remove the change to the DMA descriptor endian).
>
> Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
> Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
> --
> CC: Linux Networking List <netdev@xxxxxxxxxxxxxxx>
> CC: Arun Chandran <achandran@xxxxxxxxxx>
> CC: Haavard Skinnemoen <hskinnemoen@xxxxxxxxx>
> CC: Hans-Christian Egtvedt <egtvedt@xxxxxxxxxxxx>
> CC: Linux Kernel List <linux-kernel@xxxxxxxxxxxxxxx>
> CC: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
> ---
> drivers/net/ethernet/cadence/macb.c | 14 +++++++-------
> drivers/net/ethernet/cadence/macb.h | 20 ++++++++++++++------
> 2 files changed, 21 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index b71e316..1c3f6e7 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -449,7 +449,7 @@ static void macb_update_stats(struct macb *bp)
> WARN_ON((unsigned long)(end - p - 1) != (MACB_TPF - MACB_PFR) / 4);
>
> for(; p < end; p++, reg++)
> - *p += readl_relaxed(reg);
> + *p += cdneth_readl(reg);
> }
>
> static int macb_halt_tx(struct macb *bp)
> @@ -1587,7 +1587,7 @@ static void macb_configure_dma(struct macb *bp)
> dmacfg |= GEM_BIT(TXPBMS) | GEM_BF(RXBMS, -1L);
> dmacfg &= ~GEM_BIT(ENDIA_PKT);
> /* Tell the chip to byteswap descriptors on big-endian hosts */
> -#ifdef __BIG_ENDIAN


With https://kernel.googlesource.com/pub/scm/linux/kernel/git/davem/net-next/+/62f6924cb1543a10d05150d77f9a5e01e12c9ce1
in net-next I think CONFIG_AVR32 check is not required.

--Arun
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