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Subject: Re: [PATCH v2 2/3] iommu/dma: wire-up new dma map op .get_virt_addr
To:     Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        "hch@lst.de" <hch@lst.de>, "joro@8bytes.org" <joro@8bytes.org>,
        Ioana Ciocoi Radulescu <ruxandra.radulescu@nxp.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
        Ioana Ciornei <ioana.ciornei@nxp.com>
Cc:     Leo Li <leoyang.li@nxp.com>,
        Diana Madalina Craciun <diana.craciun@nxp.com>,
        "davem@davemloft.net" <davem@davemloft.net>,
        Madalin Bucur <madalin.bucur@nxp.com>
References: <20191024124130.16871-1-laurentiu.tudor@nxp.com>
 <20191024124130.16871-3-laurentiu.tudor@nxp.com>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <8c472ff4-1de4-42c7-f4f1-7b26043d81af@arm.com>
Date:   Mon, 28 Oct 2019 13:52:49 +0000
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On 24/10/2019 13:41, Laurentiu Tudor wrote:
> From: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> 
> Add an implementation of the newly introduced dma map op in the
> generic DMA IOMMU generic glue layer and wire it up.
> 
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> ---
>   drivers/iommu/dma-iommu.c | 16 ++++++++++++++++
>   1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index f321279baf9e..15e76232d697 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -1091,6 +1091,21 @@ static unsigned long iommu_dma_get_merge_boundary(struct device *dev)
>   	return (1UL << __ffs(domain->pgsize_bitmap)) - 1;
>   }
>   
> +static void *iommu_dma_get_virt_addr(struct device *dev, dma_addr_t dma_handle)
> +{
> +	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);

Note that we'd generally use the iommu_get_dma_domain() fastpath...

> +
> +	if (domain) {

...wherein we can also assume that the device having iommu_dma_ops 
assigned at all implies that a DMA ops domain is in place.

Robin.

> +		phys_addr_t phys;
> +
> +		phys = iommu_iova_to_phys(domain, dma_handle);
> +		if (phys)
> +			return phys_to_virt(phys);
> +	}
> +
> +	return NULL;
> +}
> +
>   static const struct dma_map_ops iommu_dma_ops = {
>   	.alloc			= iommu_dma_alloc,
>   	.free			= iommu_dma_free,
> @@ -1107,6 +1122,7 @@ static const struct dma_map_ops iommu_dma_ops = {
>   	.map_resource		= iommu_dma_map_resource,
>   	.unmap_resource		= iommu_dma_unmap_resource,
>   	.get_merge_boundary	= iommu_dma_get_merge_boundary,
> +	.get_virt_addr		= iommu_dma_get_virt_addr,
>   };
>   
>   /*
>