PCI: support the ATS capability

The PCIe ATS capability makes the Endpoint be able to request the
DMA address translation from the IOMMU and cache the translation
in the device side, thus alleviate IOMMU pressure and improve the
hardware performance in the I/O virtualization environment.

Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 72698d89e767..bd3e4a798c43 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -188,6 +188,7 @@ struct pci_cap_saved_state {
 struct pcie_link_state;
 struct pci_vpd;
 struct pci_sriov;
+struct pci_ats;
 
 /*
  * The pci_dev structure is used to describe PCI devices.
@@ -285,6 +286,7 @@ struct pci_dev {
                 struct pci_sriov *sriov;        /* SR-IOV capability related */
                 struct pci_dev *physfn; /* the PF this VF is associated with */
         };
+        struct pci_ats  *ats;   /* Address Translation Service */
 #endif
 };
 
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index e4d08c1b2e0b..c03189c56c7a 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -501,6 +501,7 @@
 #define PCI_EXT_CAP_ID_DSN      3
 #define PCI_EXT_CAP_ID_PWR      4
 #define PCI_EXT_CAP_ID_ARI      14
+#define PCI_EXT_CAP_ID_ATS      15
 #define PCI_EXT_CAP_ID_SRIOV    16
 
 /* Advanced Error Reporting */
@@ -619,6 +620,15 @@
 #define  PCI_ARI_CTRL_ACS       0x0002  /* ACS Function Groups Enable */
 #define  PCI_ARI_CTRL_FG(x)     (((x) >> 4) & 7) /* Function Group */
 
+/* Address Translation Service */
+#define PCI_ATS_CAP             0x04    /* ATS Capability Register */
+#define  PCI_ATS_CAP_QDEP(x)    ((x) & 0x1f)    /* Invalidate Queue Depth */
+#define  PCI_ATS_MAX_QDEP       32      /* Max Invalidate Queue Depth */
+#define PCI_ATS_CTRL            0x06    /* ATS Control Register */
+#define  PCI_ATS_CTRL_ENABLE    0x8000  /* ATS Enable */
+#define  PCI_ATS_CTRL_STU(x)    ((x) & 0x1f)    /* Smallest Translation Unit */
+#define  PCI_ATS_MIN_STU        12      /* shift of minimum STU block */
+
 /* Single Root I/O Virtualization */
 #define PCI_SRIOV_CAP           0x04    /* SR-IOV Capabilities */
 #define  PCI_SRIOV_CAP_VFM      0x01    /* VF Migration Capable */