[PATCH 2/3] iommu/of: Support ats-supported device-tree property

[Liviu Dudau]

On Mon, Apr 29, 2024 at 12:39:38PM +0100, Jean-Philippe Brucker wrote:
> Device-tree declares whether a PCI root-complex supports ATS by setting
> the "ats-supported" property. Copy this flag into device fwspec to let
> IOMMU drivers quickly check if they can enable ATS for a device.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe at linaro.org>
> Tested-by: Ketan Patil <ketanp at nvidia.com>

Reviewed-by: Liviu Dudau <liviu.dudau at arm.com>

> ---
>  drivers/iommu/of_iommu.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index 3afe0b48a48db..082b94c2b3291 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -105,6 +105,14 @@ static int of_iommu_configure_device(struct device_node *master_np,
>  		      of_iommu_configure_dev(master_np, dev);
>  }
>  
> +static void of_pci_check_device_ats(struct device *dev, struct device_node *np)
> +{
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +
> +	if (fwspec && of_property_read_bool(np, "ats-supported"))
> +		fwspec->flags |= IOMMU_FWSPEC_PCI_RC_ATS;
> +}
> +
>  /*
>   * Returns:
>   *  0 on success, an iommu was configured
> @@ -147,6 +155,7 @@ int of_iommu_configure(struct device *dev, struct device_node *master_np,
>  		pci_request_acs();
>  		err = pci_for_each_dma_alias(to_pci_dev(dev),
>  					     of_pci_iommu_init, &info);
> +		of_pci_check_device_ats(dev, master_np);
>  	} else {
>  		err = of_iommu_configure_device(master_np, dev, id);
>  	}
> -- 
> 2.44.0
> 

-- 
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