1 /*
2 * PCI Express Downstream Port Containment services driver
3 * Author: Keith Busch <keith.busch@intel.com>
4 *
5 * Copyright (C) 2016 Intel Corp.
6 *
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
9 * for more details.
10 */
11
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>
17
18 struct dpc_dev {
19 struct pcie_device *dev;
20 struct work_struct work;
21 int cap_pos;
22 };
23
dpc_wait_link_inactive(struct pci_dev * pdev)24 static void dpc_wait_link_inactive(struct pci_dev *pdev)
25 {
26 unsigned long timeout = jiffies + HZ;
27 u16 lnk_status;
28
29 pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
30 while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
31 !time_after(jiffies, timeout)) {
32 msleep(10);
33 pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
34 }
35 if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
36 dev_warn(&pdev->dev, "Link state not disabled for DPC event");
37 }
38
interrupt_event_handler(struct work_struct * work)39 static void interrupt_event_handler(struct work_struct *work)
40 {
41 struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
42 struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
43 struct pci_bus *parent = pdev->subordinate;
44
45 pci_lock_rescan_remove();
46 list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
47 bus_list) {
48 pci_dev_get(dev);
49 pci_stop_and_remove_bus_device(dev);
50 pci_dev_put(dev);
51 }
52 pci_unlock_rescan_remove();
53
54 dpc_wait_link_inactive(pdev);
55 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS,
56 PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT);
57 }
58
dpc_irq(int irq,void * context)59 static irqreturn_t dpc_irq(int irq, void *context)
60 {
61 struct dpc_dev *dpc = (struct dpc_dev *)context;
62 struct pci_dev *pdev = dpc->dev->port;
63 u16 status, source;
64
65 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS, &status);
66 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_SOURCE_ID,
67 &source);
68 if (!status)
69 return IRQ_NONE;
70
71 dev_info(&dpc->dev->device, "DPC containment event, status:%#06x source:%#06x\n",
72 status, source);
73
74 if (status & PCI_EXP_DPC_STATUS_TRIGGER) {
75 u16 reason = (status >> 1) & 0x3;
76
77 dev_warn(&dpc->dev->device, "DPC %s triggered, remove downstream devices\n",
78 (reason == 0) ? "unmasked uncorrectable error" :
79 (reason == 1) ? "ERR_NONFATAL" :
80 (reason == 2) ? "ERR_FATAL" : "extended error");
81 schedule_work(&dpc->work);
82 }
83 return IRQ_HANDLED;
84 }
85
86 #define FLAG(x, y) (((x) & (y)) ? '+' : '-')
dpc_probe(struct pcie_device * dev)87 static int dpc_probe(struct pcie_device *dev)
88 {
89 struct dpc_dev *dpc;
90 struct pci_dev *pdev = dev->port;
91 int status;
92 u16 ctl, cap;
93
94 dpc = devm_kzalloc(&dev->device, sizeof(*dpc), GFP_KERNEL);
95 if (!dpc)
96 return -ENOMEM;
97
98 dpc->cap_pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_DPC);
99 dpc->dev = dev;
100 INIT_WORK(&dpc->work, interrupt_event_handler);
101 set_service_data(dev, dpc);
102
103 status = devm_request_irq(&dev->device, dev->irq, dpc_irq, IRQF_SHARED,
104 "pcie-dpc", dpc);
105 if (status) {
106 dev_warn(&dev->device, "request IRQ%d failed: %d\n", dev->irq,
107 status);
108 return status;
109 }
110
111 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CAP, &cap);
112 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
113
114 ctl |= PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN;
115 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
116
117 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",
118 cap & 0xf, FLAG(cap, PCI_EXP_DPC_CAP_RP_EXT),
119 FLAG(cap, PCI_EXP_DPC_CAP_POISONED_TLP),
120 FLAG(cap, PCI_EXP_DPC_CAP_SW_TRIGGER), (cap >> 8) & 0xf,
121 FLAG(cap, PCI_EXP_DPC_CAP_DL_ACTIVE));
122 return status;
123 }
124
dpc_remove(struct pcie_device * dev)125 static void dpc_remove(struct pcie_device *dev)
126 {
127 struct dpc_dev *dpc = get_service_data(dev);
128 struct pci_dev *pdev = dev->port;
129 u16 ctl;
130
131 pci_read_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, &ctl);
132 ctl &= ~(PCI_EXP_DPC_CTL_EN_NONFATAL | PCI_EXP_DPC_CTL_INT_EN);
133 pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_CTL, ctl);
134 }
135
136 static struct pcie_port_service_driver dpcdriver = {
137 .name = "dpc",
138 .port_type = PCIE_ANY_PORT,
139 .service = PCIE_PORT_SERVICE_DPC,
140 .probe = dpc_probe,
141 .remove = dpc_remove,
142 };
143
dpc_service_init(void)144 static int __init dpc_service_init(void)
145 {
146 return pcie_port_service_register(&dpcdriver);
147 }
148 device_initcall(dpc_service_init);
149