[PATCH RFC 03/17] of: Use -ENODEV consistently in of_iommu_configure()

[Jerry Snitselaar]

On Fri, Nov 03, 2023 at 01:44:48PM -0300, Jason Gunthorpe wrote:
> Instead of returning 1 and trying to handle positive error codes just
> stick to the convention of returning -ENODEV. Remove references to ops
> from of_iommu_configure(), a NULL ops will already generate an error code.
> 
> There is no reason to check dev->bus, if err=0 at this point then the
> called configure functions thought there was an iommu and we should try to
> probe it. Remove it.
> 
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> ---
>  drivers/iommu/of_iommu.c | 42 +++++++++++++---------------------------
>  1 file changed, 13 insertions(+), 29 deletions(-)
> 
> diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
> index e2fa29c16dd758..4f77495a2543ea 100644
> --- a/drivers/iommu/of_iommu.c
> +++ b/drivers/iommu/of_iommu.c
> @@ -17,7 +17,7 @@
>  #include <linux/slab.h>
>  #include <linux/fsl/mc.h>
>  
> -#define NO_IOMMU	1
> +#define NO_IOMMU	-ENODEV
>  

With this the following can be simplified in of_iommu_configure_dev_id:

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 4f77495a2543..b9b995712029 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -61,7 +61,7 @@ static int of_iommu_configure_dev_id(struct device_node *master_np,
 			 "iommu-map-mask", &iommu_spec.np,
 			 iommu_spec.args);
 	if (err)
-		return err == -ENODEV ? NO_IOMMU : err;
+		return err;
 
 	err = of_iommu_xlate(dev, &iommu_spec);
 	of_node_put(iommu_spec.np);