diff options
| -rw-r--r-- | drivers/pci/pci.c | 75 | ||||
| -rw-r--r-- | include/linux/pci.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/pci_regs.h | 4 |
3 files changed, 79 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 4a7c6864fdf4..6112dd8d68b6 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -3066,6 +3066,81 @@ int pci_rebar_set_size(struct pci_dev *pdev, int bar, int size) } /** + * 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 * @pin: the INTx pin (1=INTA, 2=INTB, 3=INTC, 4=INTD) diff --git a/include/linux/pci.h b/include/linux/pci.h index c170c9250c8b..ab3d12a7dfed 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2061,6 +2061,7 @@ void pci_request_acs(void); bool pci_acs_enabled(struct pci_dev *pdev, u16 acs_flags); bool pci_acs_path_enabled(struct pci_dev *start, struct pci_dev *end, u16 acs_flags); +int pci_enable_atomic_ops_to_root(struct pci_dev *dev, u32 cap_mask); #define PCI_VPD_LRDT 0x80 /* Large Resource Data Type */ #define PCI_VPD_LRDT_ID(x) ((x) | PCI_VPD_LRDT) diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index 70c2b2ade048..f31b56b21714 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -624,7 +624,9 @@ #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 */ |