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/*
* PCI Express Downstream Port Containment services driver
* Author: Keith Busch <keith.busch@intel.com>
*
* 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/init.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 = devm_kzalloc(&dev->device, 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 = devm_request_irq(&dev->device, dev->irq, dpc_irq, IRQF_SHARED,
"pcie-dpc", dpc);
if (status) {
dev_warn(&dev->device, "request IRQ%d failed: %d\n", dev->irq,
status);
return status;
}
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;
}
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);
}
static struct pcie_port_service_driver dpcdriver = {
.name = "dpc",
.port_type = PCIE_ANY_PORT,
.service = PCIE_PORT_SERVICE_DPC,
.probe = dpc_probe,
.remove = dpc_remove,
};
static int __init dpc_service_init(void)
{
return pcie_port_service_register(&dpcdriver);
}
device_initcall(dpc_service_init);
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