From: Nicolas Ferre <nicolas.ferre@microchip.com>
To: Harini Katakam <harini.katakam@xilinx.com>, <davem@davemloft.net>,
<claudiu.beznea@microchip.com>, <kuba@kernel.org>,
<Conor.Dooley@microchip.com>
Cc: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<michal.simek@xilinx.com>, <harinikatakamlinux@gmail.com>,
<mstamand@ciena.com>
Subject: Re: [PATCH] net: macb: Align the dma and coherent dma masks
Date: Wed, 9 Feb 2022 11:24:43 +0100 [thread overview]
Message-ID: <e33d303b-15d6-d133-bdb3-cb63e305ef24@microchip.com> (raw)
In-Reply-To: <20220209094325.8525-1-harini.katakam@xilinx.com>
On 09/02/2022 at 10:43, Harini Katakam wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> From: Marc St-Amand <mstamand@ciena.com>
>
> Single page and coherent memory blocks can use different DMA masks
> when the macb accesses physical memory directly. The kernel is clever
> enough to allocate pages that fit into the requested address width.
>
> When using the ARM SMMU, the DMA mask must be the same for single
> pages and big coherent memory blocks. Otherwise the translation
> tables turn into one big mess.
>
> [ 74.959909] macb ff0e0000.ethernet eth0: DMA bus error: HRESP not OK
> [ 74.959989] arm-smmu fd800000.smmu: Unhandled context fault: fsr=0x402, iova=0x3165687460, fsynr=0x20001, cbfrsynra=0x877, cb=1
> [ 75.173939] macb ff0e0000.ethernet eth0: DMA bus error: HRESP not OK
> [ 75.173955] arm-smmu fd800000.smmu: Unhandled context fault: fsr=0x402, iova=0x3165687460, fsynr=0x20001, cbfrsynra=0x877, cb=1
>
> Since using the same DMA mask does not hurt direct 1:1 physical
> memory mappings, this commit always aligns DMA and coherent masks.
>
> Signed-off-by: Marc St-Amand <mstamand@ciena.com>
> Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
Ok:
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Best regards,
Nicolas
> ---
> drivers/net/ethernet/cadence/macb_main.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/cadence/macb_main.c b/drivers/net/ethernet/cadence/macb_main.c
> index 1ce20bf52f72..4c231159b562 100644
> --- a/drivers/net/ethernet/cadence/macb_main.c
> +++ b/drivers/net/ethernet/cadence/macb_main.c
> @@ -4765,7 +4765,7 @@ static int macb_probe(struct platform_device *pdev)
>
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> if (GEM_BFEXT(DAW64, gem_readl(bp, DCFG6))) {
> - dma_set_mask(&pdev->dev, DMA_BIT_MASK(44));
> + dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(44));
> bp->hw_dma_cap |= HW_DMA_CAP_64B;
> }
> #endif
> --
> 2.17.1
>
--
Nicolas Ferre
next prev parent reply other threads:[~2022-02-09 11:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-09 9:43 [PATCH] net: macb: Align the dma and coherent dma masks Harini Katakam
2022-02-09 10:24 ` Nicolas Ferre [this message]
2022-02-09 11:15 ` conor.dooley
2022-02-10 15:10 ` patchwork-bot+netdevbpf
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