Re: [PATCH v3 0/3] MIPS: SiByte: Handle PCI DMA with 64-bit memory addressing

From: Paul Burton
Date: Mon Nov 19 2018 - 14:06:42 EST


Hello,

Maciej W. Rozycki wrote:
> Hi,
>
> This mini patch series enables correct support for DMA in the presence of
> memory outside the 32-bit address range with the Broadcom SiByte SOCs and
> the relevant development boards.
>
> There is a quirk in the BCM1250, BCM1125 and BCM1125H SOCs in that their
> onchip 32-bit PCI host bridge does not support DAC, however the HT link
> (where available) does support 40-bit addressing as per the HT spec.
> Therefore the first patch sets the bus mask accordingly, and then the
> second patch enables swiotlb. See individual change descriptions for
> additional details; there's also a further discussion alongside.
>
> This has been verified with a Broadcom SWARM board equipped with 3200MiB
> of RAM (2176MiB of which the address decoder in the SOC maps above 4GiB),
> a pair of DEFPA FDDI adapters and an XHCI USB adapter. There were also
> some other PCI and PCIe devices present in the system, though not actively
> used beyond being probed at boot, and none has shown any symptoms of
> breakage.
>
> I have come across commit 9d7a224b463e ("dma-direct: always allow dma
> mask <= physiscal memory size") and realised we do need ZONE_DMA32 for
> LittleSur. Hence this v3, adding a third (second in the series) change
> for LittleSur.
>
> Also hopefully I'll have sorted out issues with threading in my MUA with
> this series update.
>
> Please apply.
>
> Maciej

Series applied to mips-next.

Thanks,
Paul

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