Re: [PATCH v3 2/3] arm,smmu: restructure code in preparation to new bindings support

[Rahul Singh <Rahul.Singh@arm.com>]

Hello Stefano,

> On 26 Jan 2021, at 10:58 pm, Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> From: Brian Woods <brian.woods@xilinx.com>
> 
> Restructure some of the code and add supporting functions for adding
> generic device tree (DT) binding support.  This will allow for using
> current Linux device trees with just modifying the chosen field to
> enable Xen.
> 
> Signed-off-by: Brian Woods <brian.woods@xilinx.com>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>

Reviewed-by: Rahul Singh <rahul.singh@arm.com>
Tested-by: Rahul Singh <rahul.singh@arm.com>

Regards,
Rahul
> ---
> Changes in v3:
> - split patch
> ---
> xen/drivers/passthrough/arm/smmu.c | 60 +++++++++++++++++-------------
> 1 file changed, 35 insertions(+), 25 deletions(-)
> 
> diff --git a/xen/drivers/passthrough/arm/smmu.c b/xen/drivers/passthrough/arm/smmu.c
> index 3898d1d737..9687762283 100644
> --- a/xen/drivers/passthrough/arm/smmu.c
> +++ b/xen/drivers/passthrough/arm/smmu.c
> @@ -782,50 +782,36 @@ static int insert_smmu_master(struct arm_smmu_device *smmu,
> 	return 0;
> }
> 
> -static int register_smmu_master(struct arm_smmu_device *smmu,
> -				struct device *dev,
> -				struct of_phandle_args *masterspec)
> +static int arm_smmu_dt_add_device_legacy(struct arm_smmu_device *smmu,
> +					 struct device *dev,
> +					 struct iommu_fwspec *fwspec)
> {
> -	int i, ret = 0;
> +	int i;
> 	struct arm_smmu_master *master;
> -	struct iommu_fwspec *fwspec;
> +	struct device_node *dev_node = dev_get_dev_node(dev);
> 
> -	master = find_smmu_master(smmu, masterspec->np);
> +	master = find_smmu_master(smmu, dev_node);
> 	if (master) {
> 		dev_err(dev,
> 			"rejecting multiple registrations for master device %s\n",
> -			masterspec->np->name);
> +			dev_node->name);
> 		return -EBUSY;
> 	}
> 
> 	master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
> 	if (!master)
> 		return -ENOMEM;
> -	master->of_node = masterspec->np;
> -
> -	ret = iommu_fwspec_init(&master->of_node->dev, smmu->dev);
> -	if (ret) {
> -		kfree(master);
> -		return ret;
> -	}
> -	fwspec = dev_iommu_fwspec_get(dev);
> -
> -	/* adding the ids here */
> -	ret = iommu_fwspec_add_ids(&masterspec->np->dev,
> -				   masterspec->args,
> -				   masterspec->args_count);
> -	if (ret)
> -		return ret;
> +	master->of_node = dev_node;
> 
> 	/* Xen: Let Xen know that the device is protected by an SMMU */
> -	dt_device_set_protected(masterspec->np);
> +	dt_device_set_protected(dev_node);
> 
> 	if (!(smmu->features & ARM_SMMU_FEAT_STREAM_MATCH)) {
> 		for (i = 0; i < fwspec->num_ids; ++i) {
> -			if (masterspec->args[i] >= smmu->num_mapping_groups) {
> +			if (fwspec->ids[i] >= smmu->num_mapping_groups) {
> 				dev_err(dev,
> 					"stream ID for master device %s greater than maximum allowed (%d)\n",
> -					masterspec->np->name, smmu->num_mapping_groups);
> +					dev_node->name, smmu->num_mapping_groups);
> 				return -ERANGE;
> 			}
> 		}
> @@ -833,6 +819,30 @@ static int register_smmu_master(struct arm_smmu_device *smmu,
> 	return insert_smmu_master(smmu, master);
> }
> 
> +static int register_smmu_master(struct arm_smmu_device *smmu,
> +				struct device *dev,
> +				struct of_phandle_args *masterspec)
> +{
> +	int ret = 0;
> +	struct iommu_fwspec *fwspec;
> +
> +	ret = iommu_fwspec_init(&masterspec->np->dev, smmu->dev);
> +	if (ret)
> +		return ret;
> +
> +	fwspec = dev_iommu_fwspec_get(&masterspec->np->dev);
> +
> +	ret = iommu_fwspec_add_ids(&masterspec->np->dev,
> +				   masterspec->args,
> +				   masterspec->args_count);
> +	if (ret)
> +		return ret;
> +
> +	return arm_smmu_dt_add_device_legacy(smmu,
> +					     &masterspec->np->dev,
> +					     fwspec);
> +}
> +
> static struct arm_smmu_device *find_smmu_for_device(struct device *dev)
> {
> 	struct arm_smmu_device *smmu;
> -- 
> 2.17.1
> 
>