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

2 files changed, 75 insertions, 0 deletions

diff --git a/Documentation/trace/events-pci.rst b/Documentation/trace/events-pci.rst
new file mode 100644
index 000000000000..03ff4ad30ddf
--- /dev/null
+++ b/Documentation/trace/events-pci.rst
@@ -0,0 +1,74 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
+Subsystem Trace Points: PCI
+===========================
+
+Overview
+========
+The PCI tracing system provides tracepoints to monitor critical hardware events
+that can impact system performance and reliability. These events normally show
+up here:
+
+	/sys/kernel/tracing/events/pci
+
+Cf. include/trace/events/pci.h for the events definitions.
+
+Available Tracepoints
+=====================
+
+pci_hp_event
+------------
+
+Monitors PCI hotplug events including card insertion/removal and link
+state changes.
+::
+
+    pci_hp_event  "%s slot:%s, event:%s\n"
+
+**Event Types**:
+
+* ``LINK_UP`` - PCIe link established
+* ``LINK_DOWN`` - PCIe link lost
+* ``CARD_PRESENT`` - Card detected in slot
+* ``CARD_NOT_PRESENT`` - Card removed from slot
+
+**Example Usage**::
+
+    # Enable the tracepoint
+    echo 1 > /sys/kernel/debug/tracing/events/pci/pci_hp_event/enable
+
+    # Monitor events (the following output is generated when a device is hotplugged)
+    cat /sys/kernel/debug/tracing/trace_pipe
+       irq/51-pciehp-88      [001] .....  1311.177459: pci_hp_event: 0000:00:02.0 slot:10, event:CARD_PRESENT
+
+       irq/51-pciehp-88      [001] .....  1311.177566: pci_hp_event: 0000:00:02.0 slot:10, event:LINK_UP
+
+pcie_link_event
+---------------
+
+Monitors PCIe link speed changes and provides detailed link status information.
+::
+
+    pcie_link_event  "%s type:%d, reason:%d, cur_bus_speed:%d, max_bus_speed:%d, width:%u, flit_mode:%u, status:%s\n"
+
+**Parameters**:
+
+* ``type`` - PCIe device type (4=Root Port, etc.)
+* ``reason`` - Reason for link change:
+
+  - ``0`` - Link retrain
+  - ``1`` - Bus enumeration
+  - ``2`` - Bandwidth notification enable
+  - ``3`` - Bandwidth notification IRQ
+  - ``4`` - Hotplug event
+
+
+**Example Usage**::
+
+    # Enable the tracepoint
+    echo 1 > /sys/kernel/debug/tracing/events/pci/pcie_link_event/enable
+
+    # Monitor events (the following output is generated when a device is hotplugged)
+    cat /sys/kernel/debug/tracing/trace_pipe
+       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
diff --git a/Documentation/trace/index.rst b/Documentation/trace/index.rst
index b4a429dc4f7a..0a40bfabcf19 100644
--- a/Documentation/trace/index.rst
+++ b/Documentation/trace/index.rst
@@ -54,6 +54,7 @@ applications.
    events-power
    events-nmi
    events-msr
+   events-pci
    boottime-trace
    histogram
    histogram-design