> -----Original Message----- > From: Jakub Kicinski <[email protected]> > Sent: Tuesday, October 22, 2019 7:23 AM > To: Madalin-cristian Bucur <[email protected]> > Cc: [email protected]; [email protected]; Roy Pledge > <[email protected]>; Laurentiu Tudor <[email protected]> > Subject: Re: [PATCH net-next 5/6] dpaa_eth: change DMA device > > On Mon, 21 Oct 2019 12:28:02 +0000, Madalin-cristian Bucur wrote: > > The DPAA Ethernet driver is using the FMan MAC as the device for DMA > > mapping. This is not actually correct, as the real DMA device is the > > FMan port (the FMan Rx port for reception and the FMan Tx port for > > transmission). Changing the device used for DMA mapping to the Fman > > Rx and Tx port devices. > > > > Signed-off-by: Madalin Bucur <[email protected]> > > Signed-off-by: Laurentiu Tudor <[email protected]> > > Curious, we also have a patch for fixing this for IXP400. > Is there something in recent kernels that uncovers this bug?
Hi Jakub, it's related to the IOMMU on ARM64, this change is just one of the many required to get IOMMU working on DPAA 1 platforms. The device used for DMA mapping was the MAC but in the DPAA it's another HW block that is actually doing the DMA transfers, the port (be it Rx or Tx). This fix just makes the code correct, to actually enable IOMMU there are some more changes and some are under discussion on other threads [1]. I'm pushing these changes so I can make other modifications to the DPAA driver while the IOMMU related open items are solved. Regards, Madalin 1. Laurentiu's IOMMU related changes: https://lkml.org/lkml/2019/4/22/357 https://lore.kernel.org/patchwork/cover/997994/ https://lore.kernel.org/patchwork/project/lkml/list/?series=396215
