On Wed, Oct 23, 2019 at 08:52:33AM -0500, Rob Herring wrote:
> On Wed, Oct 23, 2019 at 1:41 AM Benjamin Herrenschmidt
> <benh@xxxxxxxxxxxxxxxxxxx> wrote:
> >
> > On Wed, 2019-10-23 at 16:42 +1100, Michael Ellerman wrote:
> > >
> > > Right, it seems of_dma_is_coherent() has baked in the assumption that
> > > devices are non-coherent unless explicitly marked as coherent.
> > >
> > > Which is wrong on all or at least most existing powerpc systems
> > > according to Ben.
> >
> > This is probably broken on sparc(64) as well and whatever else uses
> > DT and is an intrinsicly coherent architecture (did we ever have
> > DT enabled x86s ? Wasn't OLPC such a beast ?).
>
> Only if those platforms use one of the 5 drivers that call this function:
>
> drivers/ata/ahci_qoriq.c: qoriq_priv->is_dmacoherent =
> of_dma_is_coherent(np);
> drivers/crypto/ccree/cc_driver.c: new_drvdata->coherent =
> of_dma_is_coherent(np);
> drivers/iommu/arm-smmu-v3.c: if (of_dma_is_coherent(dev->of_node))
> drivers/iommu/arm-smmu.c: if (of_dma_is_coherent(dev->of_node))
> drivers/mmc/host/sdhci-of-esdhc.c: if (of_dma_is_coherent(dev->of_node))
>
> Curious that a PPC specific driver (ahci_qoriq) calls it...
Maybe because it is not PPC specific:
arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi:
compatible = "fsl,lx2160a-ahci";
arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi:
compatible = "fsl,lx2160a-ahci";
arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi:
compatible = "fsl,lx2160a-ahci";
arch/arm64/boot/dts/freescale/fsl-lx2160a.dtsi:
compatible = "fsl,lx2160a-ahci";
drivers/ata/ahci_qoriq.c: { .compatible = "fsl,lx2160a-ahci", .data = (void *)AHCI_LX2160A},
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