2 * PCI Express Downstream Port Containment services driver
3 * Author: Keith Busch <keith.busch@intel.com>
5 * Copyright (C) 2016 Intel Corp.
7 * This file is subject to the terms and conditions of the GNU General Public
8 * License. See the file "COPYING" in the main directory of this archive
12 #include <linux/delay.h>
13 #include <linux/interrupt.h>
14 #include <linux/init.h>
15 #include <linux/pci.h>
16 #include <linux/pcieport_if.h>
19 struct pcie_device *dev;
20 struct work_struct work;
25 static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
27 unsigned long timeout = jiffies + HZ;
28 struct pci_dev *pdev = dpc->dev->port;
31 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, &status);
32 while (status & PCI_EXP_DPC_RP_BUSY &&
33 !time_after(jiffies, timeout)) {
35 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, &status);
37 if (status & PCI_EXP_DPC_RP_BUSY) {
38 dev_warn(&pdev->dev, "DPC root port still busy\n");
44 static void dpc_wait_link_inactive(struct pci_dev *pdev)
46 unsigned long timeout = jiffies + HZ;
49 pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
50 while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
51 !time_after(jiffies, timeout)) {
53 pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
55 if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
56 dev_warn(&pdev->dev, "Link state not disabled for DPC event\n");
59 static void interrupt_event_handler(struct work_struct *work)
61 struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
62 struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
63 struct pci_bus *parent = pdev->subordinate;
65 pci_lock_rescan_remove();
66 list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
69 pci_stop_and_remove_bus_device(dev);
72 pci_unlock_rescan_remove();
74 dpc_wait_link_inactive(pdev);
75 if (dpc->rp && dpc_wait_rp_inactive(dpc))
77 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS,
78 PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT);
81 static irqreturn_t dpc_irq(int irq, void *context)
83 struct dpc_dev *dpc = (struct dpc_dev *)context;
84 struct pci_dev *pdev = dpc->dev->port;
87 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, &status);
88 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_SOURCE_ID,
93 dev_info(&dpc->dev->device, "DPC containment event, status:%#06x source:%#06x\n",
96 if (status & PCI_EXP_DPC_STATUS_TRIGGER) {
97 u16 reason = (status >> 1) & 0x3;
98 u16 ext_reason = (status >> 5) & 0x3;
100 dev_warn(&dpc->dev->device, "DPC %s detected, remove downstream devices\n",
101 (reason == 0) ? "unmasked uncorrectable error" :
102 (reason == 1) ? "ERR_NONFATAL" :
103 (reason == 2) ? "ERR_FATAL" :
104 (ext_reason == 0) ? "RP PIO error" :
105 (ext_reason == 1) ? "software trigger" :
107 schedule_work(&dpc->work);
112 #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
113 static int dpc_probe(struct pcie_device *dev)
116 struct pci_dev *pdev = dev->port;
120 dpc = devm_kzalloc(&dev->device, sizeof(*dpc), GFP_KERNEL);
124 dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
126 INIT_WORK(&dpc->work, interrupt_event_handler);
127 set_service_data(dev, dpc);
129 status = devm_request_irq(&dev->device, dev->irq, dpc_irq, IRQF_SHARED,
132 dev_warn(&dev->device, "request IRQ%d failed: %d\n", dev->irq,
137 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap);
138 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
140 dpc->rp = (cap & PCI_EXP_DPC_CAP_RP_EXT);
142 ctl |= PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN;
143 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
145 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",
146 cap & 0xf, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
147 FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
148 FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), (cap >> 8) & 0xf,
149 FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
153 static void dpc_remove(struct pcie_device *dev)
155 struct dpc_dev *dpc = get_service_data(dev);
156 struct pci_dev *pdev = dev->port;
159 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
160 ctl &= ~(PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN);
161 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
164 static struct pcie_port_service_driver dpcdriver = {
166 .port_type = PCIE_ANY_PORT,
167 .service = PCIE_PORT_SERVICE_DPC,
169 .remove = dpc_remove,
172 static int __init dpc_service_init(void)
174 return pcie_port_service_register(&dpcdriver);
176 device_initcall(dpc_service_init);