Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
Merge branch 'pci/trace'
- Add generic RAS tracepoint for hotplug events (Shuai Xue)
- Add RAS tracepoint for link speed changes (Shuai Xue)
* pci/trace:
Documentation: tracing: Add PCI tracepoint documentation
PCI: trace: Add RAS tracepoint to monitor link speed changes
PCI: trace: Add generic RAS tracepoint for hotplug event
+280
-15
+74
Documentation/trace/events-pci.rst
+74
Documentation/trace/events-pci.rst
···
1
+
.. SPDX-License-Identifier: GPL-2.0
2
+
3
+
===========================
4
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Subsystem Trace Points: PCI
5
+
===========================
6
+
7
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Overview
8
+
========
9
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The PCI tracing system provides tracepoints to monitor critical hardware events
10
+
that can impact system performance and reliability. These events normally show
11
+
up here:
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13
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/sys/kernel/tracing/events/pci
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+
15
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Cf. include/trace/events/pci.h for the events definitions.
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Available Tracepoints
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=====================
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+
20
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pci_hp_event
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+
------------
22
+
23
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Monitors PCI hotplug events including card insertion/removal and link
24
+
state changes.
25
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::
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+
27
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pci_hp_event "%s slot:%s, event:%s\n"
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+
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**Event Types**:
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+
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* ``LINK_UP`` - PCIe link established
32
+
* ``LINK_DOWN`` - PCIe link lost
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* ``CARD_PRESENT`` - Card detected in slot
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* ``CARD_NOT_PRESENT`` - Card removed from slot
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+
36
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**Example Usage**::
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38
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# Enable the tracepoint
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echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable
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+
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# Monitor events (the following output is generated when a device is hotplugged)
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cat /sys/kernel/debug/tracing/trace_pipe
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irq/51-pciehp-88 [001] ..... 1311.177459: pci_hp_event: 0000:00:02.0 slot:10, event:CARD_PRESENT
44
+
45
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irq/51-pciehp-88 [001] ..... 1311.177566: pci_hp_event: 0000:00:02.0 slot:10, event:LINK_UP
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+
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pcie_link_event
48
+
---------------
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+
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Monitors PCIe link speed changes and provides detailed link status information.
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::
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pcie_link_event "%s type:%d, reason:%d, cur_bus_speed:%d, max_bus_speed:%d, width:%u, flit_mode:%u, status:%s\n"
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+
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**Parameters**:
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* ``type`` - PCIe device type (4=Root Port, etc.)
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* ``reason`` - Reason for link change:
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- ``0`` - Link retrain
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- ``1`` - Bus enumeration
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- ``2`` - Bandwidth notification enable
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- ``3`` - Bandwidth notification IRQ
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- ``4`` - Hotplug event
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+
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**Example Usage**::
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# Enable the tracepoint
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echo 1 > /sys/kernel/debug/tracing/events/pci/pcie_link_event/enable
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# Monitor events (the following output is generated when a device is hotplugged)
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cat /sys/kernel/debug/tracing/trace_pipe
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irq/51-pciehp-88 [001] ..... 381.545386: pcie_link_event: 0000:00:02.0 type:4, reason:4, cur_bus_speed:20, max_bus_speed:23, width:1, flit_mode:0, status:DLLLA
+1
Documentation/trace/index.rst
+1
Documentation/trace/index.rst
+3
drivers/pci/Makefile
+3
drivers/pci/Makefile
+25
-6
drivers/pci/hotplug/pciehp_ctrl.c
+25
-6
drivers/pci/hotplug/pciehp_ctrl.c
···
19
19
#include <linux/types.h>
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20
#include <linux/pm_runtime.h>
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#include <linux/pci.h>
22
+
#include <trace/events/pci.h>
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#include "../pci.h"
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25
#include "pciehp.h"
···
245
244
case ON_STATE:
246
245
ctrl->state = POWEROFF_STATE;
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mutex_unlock(&ctrl->state_lock);
248
-
if (events & PCI_EXP_SLTSTA_DLLSC)
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+
if (events & PCI_EXP_SLTSTA_DLLSC) {
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ctrl_info(ctrl, "Slot(%s): Link Down\n",
250
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slot_name(ctrl));
251
-
if (events & PCI_EXP_SLTSTA_PDC)
250
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trace_pci_hp_event(pci_name(ctrl->pcie->port),
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slot_name(ctrl),
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PCI_HOTPLUG_LINK_DOWN);
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+
}
254
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if (events & PCI_EXP_SLTSTA_PDC) {
252
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ctrl_info(ctrl, "Slot(%s): Card not present\n",
253
256
slot_name(ctrl));
257
+
trace_pci_hp_event(pci_name(ctrl->pcie->port),
258
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slot_name(ctrl),
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PCI_HOTPLUG_CARD_NOT_PRESENT);
260
+
}
254
261
pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
255
262
break;
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default:
···
278
269
INDICATOR_NOOP);
279
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ctrl_info(ctrl, "Slot(%s): Card not present\n",
280
271
slot_name(ctrl));
272
+
trace_pci_hp_event(pci_name(ctrl->pcie->port),
273
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slot_name(ctrl),
274
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PCI_HOTPLUG_CARD_NOT_PRESENT);
281
275
}
282
276
mutex_unlock(&ctrl->state_lock);
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277
return;
···
293
281
case OFF_STATE:
294
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ctrl->state = POWERON_STATE;
295
283
mutex_unlock(&ctrl->state_lock);
296
-
if (present)
284
+
if (present) {
297
285
ctrl_info(ctrl, "Slot(%s): Card present\n",
298
286
slot_name(ctrl));
299
-
if (link_active)
300
-
ctrl_info(ctrl, "Slot(%s): Link Up\n",
301
-
slot_name(ctrl));
287
+
trace_pci_hp_event(pci_name(ctrl->pcie->port),
288
+
slot_name(ctrl),
289
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PCI_HOTPLUG_CARD_PRESENT);
290
+
}
291
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if (link_active) {
292
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ctrl_info(ctrl, "Slot(%s): Link Up\n", slot_name(ctrl));
293
+
trace_pci_hp_event(pci_name(ctrl->pcie->port),
294
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slot_name(ctrl),
295
+
PCI_HOTPLUG_LINK_UP);
296
+
}
302
297
ctrl->request_result = pciehp_enable_slot(ctrl);
303
298
break;
304
299
default:
+2
-1
drivers/pci/hotplug/pciehp_hpc.c
+2
-1
drivers/pci/hotplug/pciehp_hpc.c
···
320
320
}
321
321
322
322
pcie_capability_read_word(pdev, PCI_EXP_LNKSTA2, &linksta2);
323
-
__pcie_update_link_speed(ctrl->pcie->port->subordinate, lnk_status, linksta2);
323
+
__pcie_update_link_speed(ctrl->pcie->port->subordinate, PCIE_HOTPLUG,
324
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lnk_status, linksta2);
324
325
325
326
if (!found) {
326
327
ctrl_info(ctrl, "Slot(%s): No device found\n",
+1
-1
drivers/pci/pci.c
+1
-1
drivers/pci/pci.c
+19
-2
drivers/pci/pci.h
+19
-2
drivers/pci/pci.h
···
5
5
#include <linux/align.h>
6
6
#include <linux/bitfield.h>
7
7
#include <linux/pci.h>
8
+
#include <trace/events/pci.h>
8
9
9
10
struct pcie_tlp_log;
10
11
···
602
601
void __pcie_print_link_status(struct pci_dev *dev, bool verbose);
603
602
void pcie_report_downtraining(struct pci_dev *dev);
604
603
605
-
static inline void __pcie_update_link_speed(struct pci_bus *bus, u16 linksta, u16 linksta2)
604
+
enum pcie_link_change_reason {
605
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PCIE_LINK_RETRAIN,
606
+
PCIE_ADD_BUS,
607
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PCIE_BWCTRL_ENABLE,
608
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PCIE_BWCTRL_IRQ,
609
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PCIE_HOTPLUG,
610
+
};
611
+
612
+
static inline void __pcie_update_link_speed(struct pci_bus *bus,
613
+
enum pcie_link_change_reason reason,
614
+
u16 linksta, u16 linksta2)
606
615
{
607
616
bus->cur_bus_speed = pcie_link_speed[linksta & PCI_EXP_LNKSTA_CLS];
608
617
bus->flit_mode = (linksta2 & PCI_EXP_LNKSTA2_FLIT) ? 1 : 0;
618
+
619
+
trace_pcie_link_event(bus,
620
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reason,
621
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FIELD_GET(PCI_EXP_LNKSTA_NLW, linksta),
622
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linksta & PCI_EXP_LNKSTA_LINK_STATUS_MASK);
609
623
}
610
-
void pcie_update_link_speed(struct pci_bus *bus);
624
+
625
+
void pcie_update_link_speed(struct pci_bus *bus, enum pcie_link_change_reason reason);
611
626
612
627
/* Single Root I/O Virtualization */
613
628
struct pci_sriov {
+2
-2
drivers/pci/pcie/bwctrl.c
+2
-2
drivers/pci/pcie/bwctrl.c
···
199
199
* Update after enabling notifications & clearing status bits ensures
200
200
* link speed is up to date.
201
201
*/
202
-
pcie_update_link_speed(port->subordinate);
202
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pcie_update_link_speed(port->subordinate, PCIE_BWCTRL_ENABLE);
203
203
}
204
204
205
205
static void pcie_bwnotif_disable(struct pci_dev *port)
···
234
234
* speed (inside pcie_update_link_speed()) after LBMS has been
235
235
* cleared to avoid missing link speed changes.
236
236
*/
237
-
pcie_update_link_speed(port->subordinate);
237
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pcie_update_link_speed(port->subordinate, PCIE_BWCTRL_IRQ);
238
238
239
239
return IRQ_HANDLED;
240
240
}
+6
-3
drivers/pci/probe.c
+6
-3
drivers/pci/probe.c
···
23
23
#include <linux/irqdomain.h>
24
24
#include <linux/pm_runtime.h>
25
25
#include <linux/bitfield.h>
26
+
#include <trace/events/pci.h>
26
27
#include "pci.h"
27
28
28
29
static struct resource busn_resource = {
···
821
820
}
822
821
EXPORT_SYMBOL_GPL(pci_speed_string);
823
822
824
-
void pcie_update_link_speed(struct pci_bus *bus)
823
+
void pcie_update_link_speed(struct pci_bus *bus,
824
+
enum pcie_link_change_reason reason)
825
825
{
826
826
struct pci_dev *bridge = bus->self;
827
827
u16 linksta, linksta2;
828
828
829
829
pcie_capability_read_word(bridge, PCI_EXP_LNKSTA, &linksta);
830
830
pcie_capability_read_word(bridge, PCI_EXP_LNKSTA2, &linksta2);
831
-
__pcie_update_link_speed(bus, linksta, linksta2);
831
+
832
+
__pcie_update_link_speed(bus, reason, linksta, linksta2);
832
833
}
833
834
EXPORT_SYMBOL_GPL(pcie_update_link_speed);
834
835
···
917
914
pcie_capability_read_dword(bridge, PCI_EXP_LNKCAP, &linkcap);
918
915
bus->max_bus_speed = pcie_link_speed[linkcap & PCI_EXP_LNKCAP_SLS];
919
916
920
-
pcie_update_link_speed(bus);
917
+
pcie_update_link_speed(bus, PCIE_ADD_BUS);
921
918
}
922
919
}
923
920
+11
drivers/pci/trace.c
+11
drivers/pci/trace.c
+129
include/trace/events/pci.h
+129
include/trace/events/pci.h
···
1
+
/* SPDX-License-Identifier: GPL-2.0 */
2
+
#undef TRACE_SYSTEM
3
+
#define TRACE_SYSTEM pci
4
+
5
+
#if !defined(_TRACE_HW_EVENT_PCI_H) || defined(TRACE_HEADER_MULTI_READ)
6
+
#define _TRACE_HW_EVENT_PCI_H
7
+
8
+
#include <uapi/linux/pci_regs.h>
9
+
#include <linux/tracepoint.h>
10
+
11
+
#define PCI_HOTPLUG_EVENT \
12
+
EM(PCI_HOTPLUG_LINK_UP, "LINK_UP") \
13
+
EM(PCI_HOTPLUG_LINK_DOWN, "LINK_DOWN") \
14
+
EM(PCI_HOTPLUG_CARD_PRESENT, "CARD_PRESENT") \
15
+
EMe(PCI_HOTPLUG_CARD_NOT_PRESENT, "CARD_NOT_PRESENT")
16
+
17
+
/* Enums require being exported to userspace, for user tool parsing */
18
+
#undef EM
19
+
#undef EMe
20
+
#define EM(a, b) TRACE_DEFINE_ENUM(a);
21
+
#define EMe(a, b) TRACE_DEFINE_ENUM(a);
22
+
23
+
PCI_HOTPLUG_EVENT
24
+
25
+
/*
26
+
* Now redefine the EM() and EMe() macros to map the enums to the strings
27
+
* that will be printed in the output.
28
+
*/
29
+
#undef EM
30
+
#undef EMe
31
+
#define EM(a, b) {a, b},
32
+
#define EMe(a, b) {a, b}
33
+
34
+
/*
35
+
* Note: For generic PCI hotplug events, we pass already-resolved strings
36
+
* (port_name, slot) instead of driver-specific structures like 'struct
37
+
* controller'. This is because different PCI hotplug drivers (pciehp, cpqphp,
38
+
* ibmphp, shpchp) define their own versions of 'struct controller' with
39
+
* different fields and helper functions. Using driver-specific structures would
40
+
* make the tracepoint interface non-generic and cause compatibility issues
41
+
* across different drivers.
42
+
*/
43
+
TRACE_EVENT(pci_hp_event,
44
+
45
+
TP_PROTO(const char *port_name,
46
+
const char *slot,
47
+
const int event),
48
+
49
+
TP_ARGS(port_name, slot, event),
50
+
51
+
TP_STRUCT__entry(
52
+
__string( port_name, port_name )
53
+
__string( slot, slot )
54
+
__field( int, event )
55
+
),
56
+
57
+
TP_fast_assign(
58
+
__assign_str(port_name);
59
+
__assign_str(slot);
60
+
__entry->event = event;
61
+
),
62
+
63
+
TP_printk("%s slot:%s, event:%s\n",
64
+
__get_str(port_name),
65
+
__get_str(slot),
66
+
__print_symbolic(__entry->event, PCI_HOTPLUG_EVENT)
67
+
)
68
+
);
69
+
70
+
#define PCI_EXP_LNKSTA_LINK_STATUS_MASK (PCI_EXP_LNKSTA_LBMS | \
71
+
PCI_EXP_LNKSTA_LABS | \
72
+
PCI_EXP_LNKSTA_LT | \
73
+
PCI_EXP_LNKSTA_DLLLA)
74
+
75
+
#define LNKSTA_FLAGS \
76
+
{ PCI_EXP_LNKSTA_LT, "LT"}, \
77
+
{ PCI_EXP_LNKSTA_DLLLA, "DLLLA"}, \
78
+
{ PCI_EXP_LNKSTA_LBMS, "LBMS"}, \
79
+
{ PCI_EXP_LNKSTA_LABS, "LABS"}
80
+
81
+
TRACE_EVENT(pcie_link_event,
82
+
83
+
TP_PROTO(struct pci_bus *bus,
84
+
unsigned int reason,
85
+
unsigned int width,
86
+
unsigned int status
87
+
),
88
+
89
+
TP_ARGS(bus, reason, width, status),
90
+
91
+
TP_STRUCT__entry(
92
+
__string( port_name, pci_name(bus->self))
93
+
__field( unsigned int, type )
94
+
__field( unsigned int, reason )
95
+
__field( unsigned int, cur_bus_speed )
96
+
__field( unsigned int, max_bus_speed )
97
+
__field( unsigned int, width )
98
+
__field( unsigned int, flit_mode )
99
+
__field( unsigned int, link_status )
100
+
),
101
+
102
+
TP_fast_assign(
103
+
__assign_str(port_name);
104
+
__entry->type = pci_pcie_type(bus->self);
105
+
__entry->reason = reason;
106
+
__entry->cur_bus_speed = bus->cur_bus_speed;
107
+
__entry->max_bus_speed = bus->max_bus_speed;
108
+
__entry->width = width;
109
+
__entry->flit_mode = bus->flit_mode;
110
+
__entry->link_status = status;
111
+
),
112
+
113
+
TP_printk("%s type:%d, reason:%d, cur_bus_speed:%d, max_bus_speed:%d, width:%u, flit_mode:%u, status:%s\n",
114
+
__get_str(port_name),
115
+
__entry->type,
116
+
__entry->reason,
117
+
__entry->cur_bus_speed,
118
+
__entry->max_bus_speed,
119
+
__entry->width,
120
+
__entry->flit_mode,
121
+
__print_flags((unsigned long)__entry->link_status, "|",
122
+
LNKSTA_FLAGS)
123
+
)
124
+
);
125
+
126
+
#endif /* _TRACE_HW_EVENT_PCI_H */
127
+
128
+
/* This part must be outside protection */
129
+
#include <trace/define_trace.h>
+7
include/uapi/linux/pci.h
+7
include/uapi/linux/pci.h
···
39
39
#define PCIIOC_MMAP_IS_MEM (PCIIOC_BASE | 0x02) /* Set mmap state to MEM space. */
40
40
#define PCIIOC_WRITE_COMBINE (PCIIOC_BASE | 0x03) /* Enable/disable write-combining. */
41
41
42
+
enum pci_hotplug_event {
43
+
PCI_HOTPLUG_LINK_UP,
44
+
PCI_HOTPLUG_LINK_DOWN,
45
+
PCI_HOTPLUG_CARD_PRESENT,
46
+
PCI_HOTPLUG_CARD_NOT_PRESENT,
47
+
};
48
+
42
49
#endif /* _UAPILINUX_PCI_H */