[PATCH 36/37] iommu/arm-smmu-v3: Add support for PCI PASID

[Jean-Philippe Brucker]

Enable PASID for PCI devices that support it.

Signed-off-by: Jean-Philippe Brucker <jean-philippe.bruc...@arm.com>
---
 drivers/iommu/arm-smmu-v3.c | 54 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index ace2f995b0c0..26935a9a5a97 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2608,6 +2608,52 @@ static void arm_smmu_disable_pri(struct 
arm_smmu_master_data *master)
        master->can_fault = false;
 }
 
+static int arm_smmu_enable_pasid(struct arm_smmu_master_data *master)
+{
+       int ret;
+       int features;
+       u8 pasid_bits;
+       int num_pasids;
+       struct pci_dev *pdev;
+
+       if (!dev_is_pci(master->dev))
+               return -ENOSYS;
+
+       pdev = to_pci_dev(master->dev);
+
+       features = pci_pasid_features(pdev);
+       if (features < 0)
+               return -ENOSYS;
+
+       num_pasids = pci_max_pasids(pdev);
+       if (num_pasids <= 0)
+               return -ENOSYS;
+
+       pasid_bits = min_t(u8, ilog2(num_pasids), master->smmu->ssid_bits);
+
+       dev_dbg(&pdev->dev, "device supports %#x PASID bits [%s%s]\n", 
pasid_bits,
+               (features & PCI_PASID_CAP_EXEC) ? "x" : "",
+               (features & PCI_PASID_CAP_PRIV) ? "p" : "");
+
+       ret = pci_enable_pasid(pdev, features);
+       return ret ? ret : pasid_bits;
+}
+
+static void arm_smmu_disable_pasid(struct arm_smmu_master_data *master)
+{
+       struct pci_dev *pdev;
+
+       if (!dev_is_pci(master->dev))
+               return;
+
+       pdev = to_pci_dev(master->dev);
+
+       if (!pdev->pasid_enabled)
+               return;
+
+       pci_disable_pasid(pdev);
+}
+
 static int arm_smmu_insert_master(struct arm_smmu_device *smmu,
                                  struct arm_smmu_master_data *master)
 {
@@ -2728,6 +2774,11 @@ static int arm_smmu_add_device(struct device *dev)
                master->ste.can_stall = true;
        }
 
+       /* PASID must be enabled before ATS */
+       ret = arm_smmu_enable_pasid(master);
+       if (ret > 0)
+               master->ssid_bits = ret;
+
        if (!arm_smmu_enable_ats(master))
                arm_smmu_enable_pri(master);
 
@@ -2746,6 +2797,7 @@ static int arm_smmu_add_device(struct device *dev)
 err_disable_pri:
        arm_smmu_disable_pri(master);
        arm_smmu_disable_ats(master);
+       arm_smmu_disable_pasid(master);
 
        return ret;
 }
@@ -2766,7 +2818,9 @@ static void arm_smmu_remove_device(struct device *dev)
        arm_smmu_remove_master(smmu, master);
 
        arm_smmu_disable_pri(master);
+       /* PASID must be disabled after ATS */
        arm_smmu_disable_ats(master);
+       arm_smmu_disable_pasid(master);
 
        iommu_group_remove_device(dev);
        iommu_device_unlink(&smmu->iommu, dev);
-- 
2.15.1

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