iommu/arm-smmu-v3-iommufd: Add hw_info to impl_ops

This will be used by Tegra241 CMDQV implementation to report a non-default
HW info data.

Link: https://patch.msgid.link/r/8a3bf5709358eb21aed2e8434534c30ecf83917c.1752126748.git.nicolinc@nvidia.com
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Pranjal Shrivastava <praan@google.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Author: nicolinc

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-iommufd.c

@@ -11,13 +11,17 @@ void *arm_smmu_hw_info(struct device *dev, u32 *length,
 		       enum iommu_hw_info_type *type)
 {
 	struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+	const struct arm_smmu_impl_ops *impl_ops = master->smmu->impl_ops;
 	struct iommu_hw_info_arm_smmuv3 *info;
 	u32 __iomem *base_idr;
 	unsigned int i;
 
 	if (*type != IOMMU_HW_INFO_TYPE_DEFAULT &&
-	    *type != IOMMU_HW_INFO_TYPE_ARM_SMMUV3)
-		return ERR_PTR(-EOPNOTSUPP);
+	    *type != IOMMU_HW_INFO_TYPE_ARM_SMMUV3) {
+		if (!impl_ops || !impl_ops->hw_info)
+			return ERR_PTR(-EOPNOTSUPP);
+		return impl_ops->hw_info(master->smmu, length, type);
+	}
 
 	info = kzalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h

@@ -721,6 +721,13 @@ struct arm_smmu_impl_ops {
 	int (*init_structures)(struct arm_smmu_device *smmu);
 	struct arm_smmu_cmdq *(*get_secondary_cmdq)(
 		struct arm_smmu_device *smmu, struct arm_smmu_cmdq_ent *ent);
+	/*
+	 * An implementation should define its own type other than the default
+	 * IOMMU_HW_INFO_TYPE_ARM_SMMUV3. And it must validate the input @type
+	 * to return its own structure.
+	 */
+	void *(*hw_info)(struct arm_smmu_device *smmu, u32 *length,
+			 enum iommu_hw_info_type *type);
 	const size_t vsmmu_size;
 	const enum iommu_viommu_type vsmmu_type;
 	int (*vsmmu_init)(struct arm_vsmmu *vsmmu,