linux-kernel - Re: [PATCH V2 1/3] iommu: of: Fix check for returning EPROBE

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Date:   Thu, 18 May 2017 13:47 +0300
From:   Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:     Sricharan R <sricharan@...eaurora.org>
Cc:     robin.murphy@....com, will.deacon@....com, joro@...tes.org,
        lorenzo.pieralisi@....com, iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, m.szyprowski@...sung.com,
        bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        linux-acpi@...r.kernel.org, tn@...ihalf.com, hanjun.guo@...aro.org,
        okaya@...eaurora.org, robh+dt@...nel.org, frowand.list@...il.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        sudeep.holla@....com, rjw@...ysocki.net, lenb@...nel.org,
        catalin.marinas@....com, arnd@...db.de, linux-arch@...r.kernel.org,
        magnus.damm@...il.com, geert@...ux-m68k.org, j.neuschaefer@....net,
        laurent.pinchart+renesas@...asonboard.com
Subject: Re: [PATCH V2 1/3] iommu: of: Fix check for returning EPROBE_DEFER

Hi Sricharan,

Thank you for the patch.

On Thursday 18 May 2017 15:37:08 Sricharan R wrote:
> Now with IOMMU probe deferral, we return -EPROBE_DEFER
> for masters that are connected to an IOMMU which is not
> probed yet, but going to get probed, so that we can attach
> the correct dma_ops. So while trying to defer the probe of
> the master, check if the of_iommu node that it is connected
> to is marked in DT as 'status=disabled', then the IOMMU is never
> is going to get probed. So simply return NULL and let the master
> work without an IOMMU.
> 
> Fixes: 7b07cbefb68d ("iommu: of: Handle IOMMU lookup failure with deferred
> probing or error") Signed-off-by: Sricharan R <sricharan@...eaurora.org>
> Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
> Tested-by: Will Deacon <will.deacon@....com>
> Tested-by: Magnus Damn <magnus.damn@...il.com>
> Acked-by: Will Deacon <will.deacon@....com>

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> ---
> [V2] Corrected spelling/case in commit log
> 
>  drivers/iommu/of_iommu.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index 9f44ee8..e6e9bec 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -118,6 +118,7 @@ static bool of_iommu_driver_present(struct device_node
> *np)
> 
>  	ops = iommu_ops_from_fwnode(fwnode);
>  	if ((ops && !ops->of_xlate) ||
> +	    !of_device_is_available(iommu_spec->np) ||
>  	    (!ops && !of_iommu_driver_present(iommu_spec->np)))
>  		return NULL;

-- 
Regards,

Laurent Pinchart