linux-kernel - [PATCH v2 2/2] pci: pciehp: Generate tracepoints for hotplug event

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Message-ID: <20241112115852.52980-3-xueshuai@linux.alibaba.com>
Date: Tue, 12 Nov 2024 19:58:52 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: lukas@...ner.de,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	linux-edac@...r.kernel.org
Cc: bhelgaas@...gle.com,
	tony.luck@...el.com,
	bp@...en8.de,
	xueshuai@...ux.alibaba.com
Subject: [PATCH v2 2/2] pci: pciehp: Generate tracepoints for hotplug event

Generate tracepoints for hotplug event.

The output like below:

$ echo 1 > /sys/kernel/debug/tracing/events/hotplug/pci_hp_event/enable
$ cat /sys/kernel/debug/tracing/trace_pipe
           <...>-206     [001] .....    40.373870: pci_hp_event: 0000:00:02.0 slot:10, trans_state:Link Down

           <...>-206     [001] .....    40.374871: pci_hp_event: 0000:00:02.0 slot:10, trans_state:Card not present

Signed-off-by: Shuai Xue <xueshuai@...ux.alibaba.com>
---
 drivers/pci/hotplug/pciehp_ctrl.c | 33 +++++++++++++++++++++++++------
 1 file changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index dcdbfcf404dd..ba099cb19f5e 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -21,6 +21,9 @@
 #include <linux/pci.h>
 #include "pciehp.h"
 
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
 /* The following routines constitute the bulk of the
    hotplug controller logic
  */
@@ -239,12 +242,20 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	case ON_STATE:
 		ctrl->state = POWEROFF_STATE;
 		mutex_unlock(&ctrl->state_lock);
-		if (events & PCI_EXP_SLTSTA_DLLSC)
+		if (events & PCI_EXP_SLTSTA_DLLSC) {
 			ctrl_info(ctrl, "Slot(%s): Link Down\n",
 				  slot_name(ctrl));
-		if (events & PCI_EXP_SLTSTA_PDC)
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_LINK_DOWN);
+		}
+		if (events & PCI_EXP_SLTSTA_PDC) {
 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
 				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_NO_PRESENT);
+		}
 		pciehp_disable_slot(ctrl, SURPRISE_REMOVAL);
 		break;
 	default:
@@ -264,6 +275,9 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 					      INDICATOR_NOOP);
 			ctrl_info(ctrl, "Slot(%s): Card not present\n",
 				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_NO_PRESENT);
 		}
 		mutex_unlock(&ctrl->state_lock);
 		return;
@@ -276,12 +290,19 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	case OFF_STATE:
 		ctrl->state = POWERON_STATE;
 		mutex_unlock(&ctrl->state_lock);
-		if (present)
+		if (present) {
 			ctrl_info(ctrl, "Slot(%s): Card present\n",
 				  slot_name(ctrl));
-		if (link_active)
-			ctrl_info(ctrl, "Slot(%s): Link Up\n",
-				  slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_CARD_PRESENT);
+		}
+		if (link_active) {
+			ctrl_info(ctrl, "Slot(%s): Link Up\n", slot_name(ctrl));
+			trace_pci_hp_event(pci_name(ctrl->pcie->port),
+					   slot_name(ctrl),
+					   PCI_HOTPLUG_LINK_UP);
+		}
 		ctrl->request_result = pciehp_enable_slot(ctrl);
 		break;
 	default:
-- 
2.39.3