[PATCH 3/4] iommu/arm-smmu-v3: Use pci_ats_supported()

[Jean-Philippe Brucker <jean-philippe@linaro.org>]

The new pci_ats_supported() function checks if a device supports ATS and
is allowed to use it.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
I dropped the Ack because I slightly changed the patch to keep the
fwspec check, since last version:
https://lore.kernel.org/linux-iommu/20200311124506.208376-8-jean-philippe@linaro.org/
---
 drivers/iommu/arm-smmu-v3.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 82508730feb7a1..39b935e86ab203 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2652,26 +2652,16 @@ static void arm_smmu_install_ste_for_dev(struct arm_smmu_master *master)
 	}
 }
 
-#ifdef CONFIG_PCI_ATS
 static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
 {
-	struct pci_dev *pdev;
+	struct device *dev = master->dev;
 	struct arm_smmu_device *smmu = master->smmu;
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(master->dev);
-
-	if (!(smmu->features & ARM_SMMU_FEAT_ATS) || !dev_is_pci(master->dev) ||
-	    !(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS) || pci_ats_disabled())
-		return false;
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 
-	pdev = to_pci_dev(master->dev);
-	return !pdev->untrusted && pdev->ats_cap;
+	return (smmu->features & ARM_SMMU_FEAT_ATS) &&
+		!(fwspec->flags & IOMMU_FWSPEC_PCI_RC_ATS) &&
+		dev_is_pci(dev) && pci_ats_supported(to_pci_dev(dev));
 }
-#else
-static bool arm_smmu_ats_supported(struct arm_smmu_master *master)
-{
-	return false;
-}
-#endif
 
 static void arm_smmu_enable_ats(struct arm_smmu_master *master)
 {
-- 
2.26.2