return 0;
}
+/**
+ * pci_enable_atomic_ops_to_root - enable AtomicOp requests to root port
+ * @dev: the PCI device
+ * @cap_mask: mask of desired AtomicOp sizes, including one or more of:
+ * PCI_EXP_DEVCAP2_ATOMIC_COMP32
+ * PCI_EXP_DEVCAP2_ATOMIC_COMP64
+ * PCI_EXP_DEVCAP2_ATOMIC_COMP128
+ *
+ * Return 0 if all upstream bridges support AtomicOp routing, egress
+ * blocking is disabled on all upstream ports, and the root port supports
+ * the requested completion capabilities (32-bit, 64-bit and/or 128-bit
+ * AtomicOp completion), or negative otherwise.
+ */
+int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask)
+{
+ struct pci_bus *bus = dev->bus;
+ struct pci_dev *bridge;
+ u32 cap, ctl2;
+
+ if (!pci_is_pcie(dev))
+ return -EINVAL;
+
+ /*
+ * Per PCIe r4.0, sec 6.15, endpoints and root ports may be
+ * AtomicOp requesters. For now, we only support endpoints as
+ * requesters and root ports as completers. No endpoints as
+ * completers, and no peer-to-peer.
+ */
+
+ switch (pci_pcie_type(dev)) {
+ case PCI_EXP_TYPE_ENDPOINT:
+ case PCI_EXP_TYPE_LEG_END:
+ case PCI_EXP_TYPE_RC_END:
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ while (bus->parent) {
+ bridge = bus->self;
+
+ pcie_capability_read_dword(bridge, PCI_EXP_DEVCAP2, &cap);
+
+ switch (pci_pcie_type(bridge)) {
+ /* Ensure switch ports support AtomicOp routing */
+ case PCI_EXP_TYPE_UPSTREAM:
+ case PCI_EXP_TYPE_DOWNSTREAM:
+ if (!(cap & PCI_EXP_DEVCAP2_ATOMIC_ROUTE))
+ return -EINVAL;
+ break;
+
+ /* Ensure root port supports all the sizes we care about */
+ case PCI_EXP_TYPE_ROOT_PORT:
+ if ((cap & cap_mask) != cap_mask)
+ return -EINVAL;
+ break;
+ }
+
+ /* Ensure upstream ports don't block AtomicOps on egress */
+ if (!bridge->has_secondary_link) {
+ pcie_capability_read_dword(bridge, PCI_EXP_DEVCTL2,
+ &ctl2);
+ if (ctl2 & PCI_EXP_DEVCTL2_ATOMIC_EGRESS_BLOCK)
+ return -EINVAL;
+ }
+
+ bus = bus->parent;
+ }
+
+ pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
+ PCI_EXP_DEVCTL2_ATOMIC_REQ);
+ return 0;
+}
+EXPORT_SYMBOL(pci_enable_atomic_ops_to_root);
+
/**
* pci_swizzle_interrupt_pin - swizzle INTx for device behind bridge
* @dev: the PCI device
#define PCI_EXP_DEVCAP2 36 /* Device Capabilities 2 */
#define PCI_EXP_DEVCAP2_ARI 0x00000020 /* Alternative Routing-ID */
#define PCI_EXP_DEVCAP2_ATOMIC_ROUTE 0x00000040 /* Atomic Op routing */
-#define PCI_EXP_DEVCAP2_ATOMIC_COMP64 0x00000100 /* Atomic 64-bit compare */
+#define PCI_EXP_DEVCAP2_ATOMIC_COMP32 0x00000080 /* 32b AtomicOp completion */
+#define PCI_EXP_DEVCAP2_ATOMIC_COMP64 0x00000100 /* 64b AtomicOp completion */
+#define PCI_EXP_DEVCAP2_ATOMIC_COMP128 0x00000200 /* 128b AtomicOp completion */
#define PCI_EXP_DEVCAP2_LTR 0x00000800 /* Latency tolerance reporting */
#define PCI_EXP_DEVCAP2_OBFF_MASK 0x000c0000 /* OBFF support mechanism */
#define PCI_EXP_DEVCAP2_OBFF_MSG 0x00040000 /* New message signaling */