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SubjectRe: [PATCH] net: macb: Clean 64b dma addresses if they are not detected
On Wed, Sep 19, 2018 at 06:08:18PM +0200, Michal Simek wrote:
> Clear ADDR64 dma bit in DMACFG register in case that HW_DMA_CAP_64B
> is not detected on 64bit system.
> The issue was observed when bootloader(u-boot) does not check macb
> feature at DCFG6 register (DAW64_OFFSET) and enabling 64bit dma support
> by default. Then macb driver is reading DMACFG register back and only
> adding 64bit dma configuration but not cleaning it out.
>
> This is also align with other features which are also cleared if they are not
> present.

Hi Michal,

>
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
>
> drivers/net/ethernet/cadence/macb_main.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 16e4ef7d7185..79707dff3f13 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -2163,6 +2163,8 @@ static void macb_configure_dma(struct macb *bp)
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> dmacfg |= GEM_BIT(ADDR64);
> + else
> + dmacfg &= ~GEM_BIT(ADDR64);
> #endif

I think you might want to do this clearing outside of the #ifdef.
If CONFIG_ARCH_DMA_ADDR_T_64BIT is not defined, we'd want to make
sure the ADDR64 is cleared. E.g something like:

dmacfg &= ~GEM_BIT(ADDR64);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
if (bp->hw_dma_cap & HW_DMA_CAP_64B)
dmacfg |= GEM_BIT(ADDR64);
#endif


Same thing for the USE_HWSTAMP/PTP flags below.

Best regards,
Edgar


> #ifdef CONFIG_MACB_USE_HWSTAMP
> if (bp->hw_dma_cap & HW_DMA_CAP_PTP)
> --
> 1.9.1
>

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