diff options
Diffstat (limited to 'drivers/misc/cxl/pci.c')
| -rw-r--r-- | drivers/misc/cxl/pci.c | 236 |
1 files changed, 218 insertions, 18 deletions
diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index efe202f9cf72..d152e2de8c93 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -55,6 +55,8 @@ pci_read_config_byte(dev, vsec + 0xa, dest) #define CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val) \ pci_write_config_byte(dev, vsec + 0xa, val) +#define CXL_WRITE_VSEC_MODE_CONTROL_BUS(bus, devfn, vsec, val) \ + pci_bus_write_config_byte(bus, devfn, vsec + 0xa, val) #define CXL_VSEC_PROTOCOL_MASK 0xe0 #define CXL_VSEC_PROTOCOL_1024TB 0x80 #define CXL_VSEC_PROTOCOL_512TB 0x40 @@ -614,36 +616,234 @@ static int setup_cxl_bars(struct pci_dev *dev) return 0; } -/* pciex node: ibm,opal-m64-window = <0x3d058 0x0 0x3d058 0x0 0x8 0x0>; */ -static int switch_card_to_cxl(struct pci_dev *dev) -{ +#ifdef CONFIG_CXL_BIMODAL + +struct cxl_switch_work { + struct pci_dev *dev; + struct work_struct work; int vsec; + int mode; +}; + +static void switch_card_to_cxl(struct work_struct *work) +{ + struct cxl_switch_work *switch_work = + container_of(work, struct cxl_switch_work, work); + struct pci_dev *dev = switch_work->dev; + struct pci_bus *bus = dev->bus; + struct pci_controller *hose = pci_bus_to_host(bus); + struct pci_dev *bridge; + struct pnv_php_slot *php_slot; + unsigned int devfn; u8 val; int rc; - dev_info(&dev->dev, "switch card to CXL\n"); + dev_info(&bus->dev, "cxl: Preparing for mode switch...\n"); + bridge = list_first_entry_or_null(&hose->bus->devices, struct pci_dev, + bus_list); + if (!bridge) { + dev_WARN(&bus->dev, "cxl: Couldn't find root port!\n"); + goto err_dev_put; + } - if (!(vsec = find_cxl_vsec(dev))) { - dev_err(&dev->dev, "ABORTING: CXL VSEC not found!\n"); + php_slot = pnv_php_find_slot(pci_device_to_OF_node(bridge)); + if (!php_slot) { + dev_err(&bus->dev, "cxl: Failed to find slot hotplug " + "information. You may need to upgrade " + "skiboot. Aborting.\n"); + goto err_dev_put; + } + + rc = CXL_READ_VSEC_MODE_CONTROL(dev, switch_work->vsec, &val); + if (rc) { + dev_err(&bus->dev, "cxl: Failed to read CAPI mode control: %i\n", rc); + goto err_dev_put; + } + devfn = dev->devfn; + + /* Release the reference obtained in cxl_check_and_switch_mode() */ + pci_dev_put(dev); + + dev_dbg(&bus->dev, "cxl: Removing PCI devices from kernel\n"); + pci_lock_rescan_remove(); + pci_hp_remove_devices(bridge->subordinate); + pci_unlock_rescan_remove(); + + /* Switch the CXL protocol on the card */ + if (switch_work->mode == CXL_BIMODE_CXL) { + dev_info(&bus->dev, "cxl: Switching card to CXL mode\n"); + val &= ~CXL_VSEC_PROTOCOL_MASK; + val |= CXL_VSEC_PROTOCOL_256TB | CXL_VSEC_PROTOCOL_ENABLE; + rc = pnv_cxl_enable_phb_kernel_api(hose, true); + if (rc) { + dev_err(&bus->dev, "cxl: Failed to enable kernel API" + " on real PHB, aborting\n"); + goto err_free_work; + } + } else { + dev_WARN(&bus->dev, "cxl: Switching card to PCI mode not supported!\n"); + goto err_free_work; + } + + rc = CXL_WRITE_VSEC_MODE_CONTROL_BUS(bus, devfn, switch_work->vsec, val); + if (rc) { + dev_err(&bus->dev, "cxl: Failed to configure CXL protocol: %i\n", rc); + goto err_free_work; + } + + /* + * The CAIA spec (v1.1, Section 10.6 Bi-modal Device Support) states + * we must wait 100ms after this mode switch before touching PCIe config + * space. + */ + msleep(100); + + /* + * Hot reset to cause the card to come back in cxl mode. A + * OPAL_RESET_PCI_LINK would be sufficient, but currently lacks support + * in skiboot, so we use a hot reset instead. + * + * We call pci_set_pcie_reset_state() on the bridge, as a CAPI card is + * guaranteed to sit directly under the root port, and setting the reset + * state on a device directly under the root port is equivalent to doing + * it on the root port iself. + */ + dev_info(&bus->dev, "cxl: Configuration write complete, resetting card\n"); + pci_set_pcie_reset_state(bridge, pcie_hot_reset); + pci_set_pcie_reset_state(bridge, pcie_deassert_reset); + + dev_dbg(&bus->dev, "cxl: Offlining slot\n"); + rc = pnv_php_set_slot_power_state(&php_slot->slot, OPAL_PCI_SLOT_OFFLINE); + if (rc) { + dev_err(&bus->dev, "cxl: OPAL offlining call failed: %i\n", rc); + goto err_free_work; + } + + dev_dbg(&bus->dev, "cxl: Onlining and probing slot\n"); + rc = pnv_php_set_slot_power_state(&php_slot->slot, OPAL_PCI_SLOT_ONLINE); + if (rc) { + dev_err(&bus->dev, "cxl: OPAL onlining call failed: %i\n", rc); + goto err_free_work; + } + + pci_lock_rescan_remove(); + pci_hp_add_devices(bridge->subordinate); + pci_unlock_rescan_remove(); + + dev_info(&bus->dev, "cxl: CAPI mode switch completed\n"); + kfree(switch_work); + return; + +err_dev_put: + /* Release the reference obtained in cxl_check_and_switch_mode() */ + pci_dev_put(dev); +err_free_work: + kfree(switch_work); +} + +int cxl_check_and_switch_mode(struct pci_dev *dev, int mode, int vsec) +{ + struct cxl_switch_work *work; + u8 val; + int rc; + + if (!cpu_has_feature(CPU_FTR_HVMODE)) return -ENODEV; + + if (!vsec) { + vsec = find_cxl_vsec(dev); + if (!vsec) { + dev_info(&dev->dev, "CXL VSEC not found\n"); + return -ENODEV; + } } - if ((rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val))) { - dev_err(&dev->dev, "failed to read current mode control: %i", rc); + rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val); + if (rc) { + dev_err(&dev->dev, "Failed to read current mode control: %i", rc); return rc; } - val &= ~CXL_VSEC_PROTOCOL_MASK; - val |= CXL_VSEC_PROTOCOL_256TB | CXL_VSEC_PROTOCOL_ENABLE; - if ((rc = CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val))) { - dev_err(&dev->dev, "failed to enable CXL protocol: %i", rc); - return rc; + + if (mode == CXL_BIMODE_PCI) { + if (!(val & CXL_VSEC_PROTOCOL_ENABLE)) { + dev_info(&dev->dev, "Card is already in PCI mode\n"); + return 0; + } + /* + * TODO: Before it's safe to switch the card back to PCI mode + * we need to disable the CAPP and make sure any cachelines the + * card holds have been flushed out. Needs skiboot support. + */ + dev_WARN(&dev->dev, "CXL mode switch to PCI unsupported!\n"); + return -EIO; } + + if (val & CXL_VSEC_PROTOCOL_ENABLE) { + dev_info(&dev->dev, "Card is already in CXL mode\n"); + return 0; + } + + dev_info(&dev->dev, "Card is in PCI mode, scheduling kernel thread " + "to switch to CXL mode\n"); + + work = kmalloc(sizeof(struct cxl_switch_work), GFP_KERNEL); + if (!work) + return -ENOMEM; + + pci_dev_get(dev); + work->dev = dev; + work->vsec = vsec; + work->mode = mode; + INIT_WORK(&work->work, switch_card_to_cxl); + + schedule_work(&work->work); + /* - * The CAIA spec (v0.12 11.6 Bi-modal Device Support) states - * we must wait 100ms after this mode switch before touching - * PCIe config space. + * We return a failure now to abort the driver init. Once the + * link has been cycled and the card is in cxl mode we will + * come back (possibly using the generic cxl driver), but + * return success as the card should then be in cxl mode. + * + * TODO: What if the card comes back in PCI mode even after + * the switch? Don't want to spin endlessly. */ - msleep(100); + return -EBUSY; +} +EXPORT_SYMBOL_GPL(cxl_check_and_switch_mode); + +#endif /* CONFIG_CXL_BIMODAL */ + +static int setup_cxl_protocol_area(struct pci_dev *dev) +{ + u8 val; + int rc; + int vsec = find_cxl_vsec(dev); + + if (!vsec) { + dev_info(&dev->dev, "CXL VSEC not found\n"); + return -ENODEV; + } + + rc = CXL_READ_VSEC_MODE_CONTROL(dev, vsec, &val); + if (rc) { + dev_err(&dev->dev, "Failed to read current mode control: %i\n", rc); + return rc; + } + + if (!(val & CXL_VSEC_PROTOCOL_ENABLE)) { + dev_err(&dev->dev, "Card not in CAPI mode!\n"); + return -EIO; + } + + if ((val & CXL_VSEC_PROTOCOL_MASK) != CXL_VSEC_PROTOCOL_256TB) { + val &= ~CXL_VSEC_PROTOCOL_MASK; + val |= CXL_VSEC_PROTOCOL_256TB; + rc = CXL_WRITE_VSEC_MODE_CONTROL(dev, vsec, val); + if (rc) { + dev_err(&dev->dev, "Failed to set CXL protocol area: %i\n", rc); + return rc; + } + } return 0; } @@ -1249,7 +1449,7 @@ static int cxl_configure_adapter(struct cxl *adapter, struct pci_dev *dev) if ((rc = setup_cxl_bars(dev))) return rc; - if ((rc = switch_card_to_cxl(dev))) + if ((rc = setup_cxl_protocol_area(dev))) return rc; if ((rc = cxl_update_image_control(adapter))) |