PCI/ATS: Add PRI stubs

maillist inclusion
category: feature
bugzilla: 51855
CVE: NA

Reference: https://jpbrucker.net/git/linux/commit/?h=sva/2021-03-01&id=f61a8d9eceb10611c5f0bb151ad3dbc754bc6467

---------------------------------------------

The SMMUv3 driver, which can be built without CONFIG_PCI, will soon gain
support for PRI.  Partially revert commit c6e9aefb ("PCI/ATS: Remove
unused PRI and PASID stubs") to re-introduce the PRI stubs, and avoid
adding more #ifdefs to the SMMU driver.
Acked-by: NBjorn Helgaas <bhelgaas@google.com>
Reviewed-by: NKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: NJean-Philippe Brucker <jean-philippe@linaro.org>
Signed-off-by: NLijun Fang <fanglijun3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

include/linux/pci-ats.h

@@ -30,6 +30,13 @@ int pci_reset_pri(struct pci_dev *pdev);
 int pci_prg_resp_pasid_required(struct pci_dev *pdev);
 bool pci_pri_supported(struct pci_dev *pdev);
 #else
+static inline int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
+{ return -ENODEV; }
+static inline void pci_disable_pri(struct pci_dev *pdev) { }
+static inline int pci_reset_pri(struct pci_dev *pdev)
+{ return -ENODEV; }
+static inline int pci_prg_resp_pasid_required(struct pci_dev *pdev)
+{ return 0; }
 static inline bool pci_pri_supported(struct pci_dev *pdev)
 { return false; }
 #endif /* CONFIG_PCI_PRI */