2022-02-09 13:12:12

by Harini Katakam

Subject: [PATCH] net: macb: Align the dma and coherent dma masks

From: Marc St-Amand <[email protected]>

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 <[email protected]>
Signed-off-by: Harini Katakam <[email protected]>
---
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

2022-02-11 08:11:32

by patchwork-bot+netdevbpf

Subject: Re: [PATCH] net: macb: Align the dma and coherent dma masks

Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <[email protected]>:

On Wed, 9 Feb 2022 15:13:25 +0530 you wrote:
> From: Marc St-Amand <[email protected]>
>
> 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.
>
> [...]

Here is the summary with links:
- net: macb: Align the dma and coherent dma masks
https://git.kernel.org/netdev/net/c/37f7860602b5

You are awesome, thank you!
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