diff options
Diffstat (limited to 'drivers/pci/pcie/pcie-dpc.c')
| -rw-r--r-- | drivers/pci/pcie/pcie-dpc.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c new file mode 100644 index 000000000..ab552f1bc --- /dev/null +++ b/drivers/pci/pcie/pcie-dpc.c @@ -0,0 +1,163 @@ +/* + * PCI Express Downstream Port Containment services driver + * Copyright (C) 2016 Intel Corp. + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ + +#include <linux/delay.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/pcieport_if.h> + +struct dpc_dev { + struct pcie_device *dev; + struct work_struct work; + int cap_pos; +}; + +static void dpc_wait_link_inactive(struct pci_dev *pdev) +{ + unsigned long timeout = jiffies + HZ; + u16 lnk_status; + + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); + while (lnk_status & PCI_EXP_LNKSTA_DLLLA && + !time_after(jiffies, timeout)) { + msleep(10); + pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status); + } + if (lnk_status & PCI_EXP_LNKSTA_DLLLA) + dev_warn(&pdev->dev, "Link state not disabled for DPC event"); +} + +static void interrupt_event_handler(struct work_struct *work) +{ + struct dpc_dev *dpc = container_of(work, struct dpc_dev, work); + struct pci_dev *dev, *temp, *pdev = dpc->dev->port; + struct pci_bus *parent = pdev->subordinate; + + pci_lock_rescan_remove(); + list_for_each_entry_safe_reverse(dev, temp, &parent->devices, + bus_list) { + pci_dev_get(dev); + pci_stop_and_remove_bus_device(dev); + pci_dev_put(dev); + } + pci_unlock_rescan_remove(); + + dpc_wait_link_inactive(pdev); + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, + PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT); +} + +static irqreturn_t dpc_irq(int irq, void *context) +{ + struct dpc_dev *dpc = (struct dpc_dev *)context; + struct pci_dev *pdev = dpc->dev->port; + u16 status, source; + + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, &status); + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_SOURCE_ID, + &source); + if (!status) + return IRQ_NONE; + + dev_info(&dpc->dev->device, "DPC containment event, status:%#06x source:%#06x\n", + status, source); + + if (status & PCI_EXP_DPC_STATUS_TRIGGER) { + u16 reason = (status >> 1) & 0x3; + + dev_warn(&dpc->dev->device, "DPC %s triggered, remove downstream devices\n", + (reason == 0) ? "unmasked uncorrectable error" : + (reason == 1) ? "ERR_NONFATAL" : + (reason == 2) ? "ERR_FATAL" : "extended error"); + schedule_work(&dpc->work); + } + return IRQ_HANDLED; +} + +#define FLAG(x, y) (((x) & (y)) ? '+' : '-') +static int dpc_probe(struct pcie_device *dev) +{ + struct dpc_dev *dpc; + struct pci_dev *pdev = dev->port; + int status; + u16 ctl, cap; + + dpc = kzalloc(sizeof(*dpc), GFP_KERNEL); + if (!dpc) + return -ENOMEM; + + dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC); + dpc->dev = dev; + INIT_WORK(&dpc->work, interrupt_event_handler); + set_service_data(dev, dpc); + + status = request_irq(dev->irq, dpc_irq, IRQF_SHARED, "pcie-dpc", dpc); + if (status) { + dev_warn(&dev->device, "request IRQ%d failed: %d\n", dev->irq, + status); + goto out; + } + + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap); + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl); + + ctl |= PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN; + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl); + + dev_info(&dev->device, "DPC error containment capabilities: Int Msg #%d, RPExt%c PoisonedTLP%c SwTrigger%c RP PIO Log %d, DL_ActiveErr%c\n", + cap & 0xf, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT), + FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP), + FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), (cap >> 8) & 0xf, + FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE)); + return status; + out: + kfree(dpc); + return status; +} + +static void dpc_remove(struct pcie_device *dev) +{ + struct dpc_dev *dpc = get_service_data(dev); + struct pci_dev *pdev = dev->port; + u16 ctl; + + pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl); + ctl &= ~(PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN); + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl); + + free_irq(dev->irq, dpc); + kfree(dpc); +} + +static struct pcie_port_service_driver dpcdriver = { + .name = "dpc", + .port_type = PCI_EXP_TYPE_ROOT_PORT | PCI_EXP_TYPE_DOWNSTREAM, + .service = PCIE_PORT_SERVICE_DPC, + .probe = dpc_probe, + .remove = dpc_remove, +}; + +static int __init dpc_service_init(void) +{ + return pcie_port_service_register(&dpcdriver); +} + +static void __exit dpc_service_exit(void) +{ + pcie_port_service_unregister(&dpcdriver); +} + +MODULE_DESCRIPTION("PCI Express Downstream Port Containment driver"); +MODULE_AUTHOR("Keith Busch <keith.busch@intel.com>"); +MODULE_LICENSE("GPL"); +MODULE_VERSION("0.1"); + +module_init(dpc_service_init); +module_exit(dpc_service_exit); |