Re: [PATCH v2] xen/iommu: smmu: Silence clang in arm_smmu_device_dt_probe()

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Fri, 2 Apr 2021, Julien Grall wrote:
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> Clang 11 will throw the following error:
> 
> smmu.c:2284:18: error: cast to smaller integer type 'enum 
> arm_smmu_arch_version' from 'const void *' 
> [-Werror,-Wvoid-pointer-to-enum-cast]
>         smmu->version = (enum arm_smmu_arch_version)of_id->data;
>                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> The error can be prevented by initially casting to (uintptr_t) and then
> enum.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>

Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
> 
> Changes in v2:
>     - Cast to (uintptr_t) rather than introduce separate pointer
>     (requested by Andrew).
> 
> Only build tested
> ---
>  xen/drivers/passthrough/arm/smmu.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/xen/drivers/passthrough/arm/smmu.c 
> b/xen/drivers/passthrough/arm/smmu.c
> index 20ac672e91b6..fab7be8b48bb 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -2382,7 +2382,7 @@ static int arm_smmu_device_dt_probe(struct 
> platform_device *pdev)
>       smmu->dev = dev;
>  
>       of_id = of_match_node(arm_smmu_of_match, dev->of_node);
> -     smmu->version = (enum arm_smmu_arch_version)of_id->data;
> +     smmu->version = (enum arm_smmu_arch_version)(uintptr_t)of_id->data;
>  
>       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>       smmu->base = devm_ioremap_resource(dev, res);
> -- 
> 2.17.1
>