Re: [PATCH 2/2] PCI: cadence: Add debugfs property to provide LTSSM status of the PCIe link

From: Hans Zhang

Date: Tue Mar 17 2026 - 11:39:57 EST




On 2026/3/17 14:31, Shawn Lin wrote:
在 2026/03/15 星期日 23:55, Hans Zhang 写道:
Add the debugfs property to provide a view of the current link's LTSSM
status from the Root Port device.

Test example:
   # cat /sys/kernel/debug/cdns_pcie_a0c0000.pcie/ltssm_status
   L0_STATE (0x29)

Signed-off-by: Hans Zhang <18255117159@xxxxxxx>
---
  Documentation/ABI/testing/debugfs-cdns-pcie   |   5 +
  drivers/pci/controller/cadence/Kconfig        |   9 +
  drivers/pci/controller/cadence/Makefile       |   1 +
  .../controller/cadence/pcie-cadence-debugfs.c | 211 ++++++++++++++++++
  .../pci/controller/cadence/pcie-cadence-ep.c  |   2 +
  .../cadence/pcie-cadence-host-hpa.c           |   8 +-
  .../controller/cadence/pcie-cadence-host.c    |   8 +-
  drivers/pci/controller/cadence/pcie-cadence.h | 145 ++++++++++++
  8 files changed, 387 insertions(+), 2 deletions(-)
  create mode 100644 Documentation/ABI/testing/debugfs-cdns-pcie
  create mode 100644 drivers/pci/controller/cadence/pcie-cadence- debugfs.c

diff --git a/Documentation/ABI/testing/debugfs-cdns-pcie b/ Documentation/ABI/testing/debugfs-cdns-pcie
new file mode 100644
index 000000000000..4118303e75f3
--- /dev/null
+++ b/Documentation/ABI/testing/debugfs-cdns-pcie
@@ -0,0 +1,5 @@
+What:        /sys/kernel/debug/cdns_pcie_<dev>/ltssm_status
+Date:        January 2026

March?


Hi Shawn,

Thank you very much for your review comments. Because this patch was released to my local environment quite early, it was released a long time ago and has not been sent out yet. Will change.



+Contact:    Hans Zhang <18255117159@xxxxxxx>
+Description:    (RO) Read will return the current PCIe LTSSM state in both
+        string and raw value.
diff --git a/drivers/pci/controller/cadence/Kconfig b/drivers/pci/ controller/cadence/Kconfig
index 9e651d545973..b277c5f6e196 100644
--- a/drivers/pci/controller/cadence/Kconfig
+++ b/drivers/pci/controller/cadence/Kconfig
@@ -6,6 +6,15 @@ menu "Cadence-based PCIe controllers"
  config PCIE_CADENCE
      tristate
+config PCIE_CADENCE_DEBUGFS
+    bool "Cadence PCIe debugfs entries"
+    depends on DEBUG_FS
+    depends on PCIE_CADENCE_HOST || PCIE_CADENCE_EP
+    help
+      Say Y here to enable debugfs entries for the PCIe controller. These
+      entries provide various debug features related to the controller and
+      the LTSSM status of link can be displayed.
+
  config PCIE_CADENCE_HOST
      tristate
      depends on OF
diff --git a/drivers/pci/controller/cadence/Makefile b/drivers/pci/ controller/cadence/Makefile
index b8ec1cecfaa8..2cdc4617e0c2 100644
--- a/drivers/pci/controller/cadence/Makefile
+++ b/drivers/pci/controller/cadence/Makefile
@@ -4,6 +4,7 @@ pcie-cadence-host-mod-y := pcie-cadence-host-common.o pcie-cadence-host.o pcie-c
  pcie-cadence-ep-mod-y := pcie-cadence-ep.o
  obj-$(CONFIG_PCIE_CADENCE) = pcie-cadence-mod.o
+obj-$(CONFIG_PCIE_CADENCE_DEBUGFS) += pcie-cadence-debugfs.o
  obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host-mod.o
  obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep-mod.o
  obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
diff --git a/drivers/pci/controller/cadence/pcie-cadence-debugfs.c b/ drivers/pci/controller/cadence/pcie-cadence-debugfs.c
new file mode 100644
index 000000000000..568c7af6e18f
--- /dev/null
+++ b/drivers/pci/controller/cadence/pcie-cadence-debugfs.c
@@ -0,0 +1,211 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * PCIe controller driver for CIX's sky1 SoCs
+ *
+ * Copyright 2026 Cix Technology Group Co., Ltd.
+ * Author: Hans Zhang <hans.zhang@xxxxxxxxxxx>
+ */
+
+#include <linux/debugfs.h>
+
+#include "pcie-cadence.h"
+
+#define CDNS_DEBUGFS_BUF_MAX        128
+
+static const char *ltssm_status_string(enum cdns_pcie_ltssm ltssm)
+{
+    const char *str;
+
+    switch (ltssm) {
+#define DW_PCIE_LTSSM_NAME(n) case n: str = #n; break
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_QUIET);

Seriously? Synopsys code in cdns driver?

The Synopsys code was also one that I submitted, but I forgot to make any modifications. Will change.


+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_QUIET_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_ACTIVE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_ACTIVE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_ACTIVE_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DETECT_ACTIVE_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RCVR_DETECTED_ST);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RCVR_DETECTED_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_ACTIVE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_ACTIVE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_ACTIVE_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_ACTIVE_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_CONFIG);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_CONFIG_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_CONFIG_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_RC);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_RC_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_RC_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_ACC_RC);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_RC);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_RC_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_RC);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_EP);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_EP_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_START_EP_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LW_ACC_EP);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_EP);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_EP_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_EP);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_EP_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DUMMY_STATE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_COMPLETE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_COMPLETE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_COMPLETE_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_IDLE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_CONFIG_IDLE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DUMMY_STATE_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DUMMY_STATE_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DUMMY_STATE_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0_STATE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_RCVR_LOCK);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_RCVR_LOCK_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_RCVR_CFG);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_RCVR_CFG_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_IDLE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_IDLE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_5);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_6);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_DISABLE_LINK_7);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_HOT_RESET);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_HOT_RESET_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_HOT_RESET_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_HOT_RESET_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L0S_5);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_WAIT_FOR_LINK_TX);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_FTS_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_FTS_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_FTS_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_ELEC_IDLE_ST);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_ELEC_IDLE_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_ELEC_IDLE_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_TX_ELEC_IDLE_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_SPEED);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_SPEED_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_SPEED_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_SPEED_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_5);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_6);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_7);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_8);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ENTRY);
+ DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ENTRY_FROM_RECOVERY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_EXIT_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_EXIT);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_5);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ACTIVE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_IDLE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L1_EXIT);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_5);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_L2_IDLE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_3);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_4);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_5);
+ DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_FROM_RECOVERY);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ACTIVE);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE0);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE2_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE2_2);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE3_1);
+    DW_PCIE_LTSSM_NAME(CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE3_2);
+    default:
+        str = "CDNS_PCIE_LTSSM_UNKNOWN";
+        break;
+    }
+
+    return str + strlen("CDNS_PCIE_LTSSM_");
+}
+
+static int ltssm_status_show(struct seq_file *s, void *v)
+{
+    struct cdns_pcie *pci = s->private;
+    enum cdns_pcie_ltssm ltssm;
+    u32 reg;
+
+    if (pci->is_hpa) {
+        reg = cdns_pcie_hpa_readl(pci, REG_BANK_IP_REG,
+                    CDNS_PCIE_HPA_PHY_DBG_STS_REG0);
+        ltssm = FIELD_GET(GENMASK(27, 20), reg);
+    } else {
+        reg = cdns_pcie_readl(pci, CDNS_PCIE_LM_BASE);
+        ltssm = FIELD_GET(GENMASK(29, 24), reg);
+    }

What are these magic numbers? Please use macro with proper
names.

Will Change.


Best regards,
Hans


+
+    seq_printf(s, "%s (0x%02x)\n", ltssm_status_string(ltssm), ltssm);
+
+    return 0;
+}
+
+static int ltssm_status_open(struct inode *inode, struct file *file)
+{
+    return single_open(file, ltssm_status_show, inode->i_private);
+}
+
+static const struct file_operations cdns_pcie_ltssm_status_ops = {
+    .open = ltssm_status_open,
+    .read = seq_read,
+};
+
+static void cdns_pcie_ltssm_debugfs_init(struct cdns_pcie *pci, struct dentry *dir)
+{
+    debugfs_create_file("ltssm_status", 0444, dir, pci,
+                &cdns_pcie_ltssm_status_ops);
+}
+
+void cdns_pcie_debugfs_deinit(struct cdns_pcie *pci)
+{
+    if (!pci->debug_dir)
+        return;
+
+    debugfs_remove_recursive(pci->debug_dir);
+}
+
+void cdns_pcie_debugfs_init(struct cdns_pcie *pci)
+{
+    char dirname[CDNS_DEBUGFS_BUF_MAX];
+    struct device *dev = pci->dev;
+
+    /* Create main directory for each platform driver. */
+    snprintf(dirname, CDNS_DEBUGFS_BUF_MAX, "cdns_pcie_%s", dev_name(dev));
+    pci->debug_dir = debugfs_create_dir(dirname, NULL);
+
+    cdns_pcie_ltssm_debugfs_init(pci, pci->debug_dir);
+}
diff --git a/drivers/pci/controller/cadence/pcie-cadence-ep.c b/ drivers/pci/controller/cadence/pcie-cadence-ep.c
index c0e1194a936b..7849f63f53ab 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-ep.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-ep.c
@@ -761,6 +761,8 @@ int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep)
      pci_epc_init_notify(epc);
+    cdns_pcie_debugfs_init(pcie);
+
      return 0;
   free_epc_mem:
diff --git a/drivers/pci/controller/cadence/pcie-cadence-host-hpa.c b/ drivers/pci/controller/cadence/pcie-cadence-host-hpa.c
index 0f540bed58e8..38bd74d9e071 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host-hpa.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host-hpa.c
@@ -360,7 +360,13 @@ int cdns_pcie_hpa_host_setup(struct cdns_pcie_rc *rc)
      if (!bridge->ops)
          bridge->ops = &cdns_pcie_hpa_host_ops;
-    return pci_host_probe(bridge);
+    ret = pci_host_probe(bridge);
+    if (ret)
+        return ret;
+
+    cdns_pcie_debugfs_init(pcie);
+
+    return 0;
  }
  EXPORT_SYMBOL_GPL(cdns_pcie_hpa_host_setup);
diff --git a/drivers/pci/controller/cadence/pcie-cadence-host.c b/ drivers/pci/controller/cadence/pcie-cadence-host.c
index db3154c1eccb..23ca1e703953 100644
--- a/drivers/pci/controller/cadence/pcie-cadence-host.c
+++ b/drivers/pci/controller/cadence/pcie-cadence-host.c
@@ -416,7 +416,13 @@ int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
      if (!bridge->ops)
          bridge->ops = &cdns_pcie_host_ops;
-    return pci_host_probe(bridge);
+    ret = pci_host_probe(bridge);
+    if (ret)
+        return ret;
+
+    cdns_pcie_debugfs_init(pcie);
+
+    return 0;
  }
  EXPORT_SYMBOL_GPL(cdns_pcie_host_setup);
diff --git a/drivers/pci/controller/cadence/pcie-cadence.h b/drivers/ pci/controller/cadence/pcie-cadence.h
index c8cb19f7622f..6db98b7d24cb 100644
--- a/drivers/pci/controller/cadence/pcie-cadence.h
+++ b/drivers/pci/controller/cadence/pcie-cadence.h
@@ -42,6 +42,137 @@ enum cdns_pcie_reg_bank {
      REG_BANKS_MAX,
  };
+enum cdns_pcie_ltssm {
+    CDNS_PCIE_LTSSM_DETECT_QUIET        = 0,
+    CDNS_PCIE_LTSSM_DETECT_QUIET_ENTRY    = 1,
+    CDNS_PCIE_LTSSM_DETECT_ACTIVE        = 2,
+    CDNS_PCIE_LTSSM_DETECT_ACTIVE_1        = 3,
+    CDNS_PCIE_LTSSM_DETECT_ACTIVE_2        = 4,
+    CDNS_PCIE_LTSSM_DETECT_ACTIVE_3        = 5,
+    CDNS_PCIE_LTSSM_RCVR_DETECTED_ST    = 6,
+    CDNS_PCIE_LTSSM_RCVR_DETECTED_1        = 7,
+    CDNS_PCIE_LTSSM_POLLING_ACTIVE        = 8,
+    CDNS_PCIE_LTSSM_POLLING_ACTIVE_1    = 9,
+    CDNS_PCIE_LTSSM_POLLING_ACTIVE_2    = 10,
+    CDNS_PCIE_LTSSM_POLLING_ACTIVE_3    = 11,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE    = 12,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_1    = 13,
+    CDNS_PCIE_LTSSM_POLLING_CONFIG        = 14,
+    CDNS_PCIE_LTSSM_POLLING_CONFIG_1    = 15,
+    CDNS_PCIE_LTSSM_POLLING_CONFIG_2    = 16,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_RC    = 17,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_RC_1    = 18,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_RC_2    = 19,
+    CDNS_PCIE_LTSSM_CONFIG_LW_ACC_RC    = 20,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_RC    = 21,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_RC_1 = 22,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_RC    = 23,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_EP    = 24,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_EP_1    = 25,
+    CDNS_PCIE_LTSSM_CONFIG_LW_START_EP_2    = 26,
+    CDNS_PCIE_LTSSM_CONFIG_LW_ACC_EP    = 27,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_EP    = 28,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_WAIT_EP_1 = 29,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_EP    = 30,
+    CDNS_PCIE_LTSSM_CONFIG_LANENUM_ACC_EP_1    = 31,
+    CDNS_PCIE_LTSSM_DUMMY_STATE_1        = 32,
+    CDNS_PCIE_LTSSM_CONFIG_COMPLETE        = 33,
+    CDNS_PCIE_LTSSM_CONFIG_COMPLETE_1    = 34,
+    CDNS_PCIE_LTSSM_CONFIG_COMPLETE_2    = 35,
+    CDNS_PCIE_LTSSM_CONFIG_IDLE        = 36,
+    CDNS_PCIE_LTSSM_CONFIG_IDLE_1        = 37,
+    CDNS_PCIE_LTSSM_DUMMY_STATE_2        = 38,
+    CDNS_PCIE_LTSSM_DUMMY_STATE_3        = 39,
+    CDNS_PCIE_LTSSM_DUMMY_STATE_4        = 40,
+    CDNS_PCIE_LTSSM_L0_STATE        = 41,
+    CDNS_PCIE_LTSSM_RECOVERY_RCVR_LOCK    = 42,
+    CDNS_PCIE_LTSSM_RECOVERY_RCVR_LOCK_1    = 43,
+    CDNS_PCIE_LTSSM_RECOVERY_RCVR_CFG    = 44,
+    CDNS_PCIE_LTSSM_RECOVERY_RCVR_CFG_1    = 45,
+    CDNS_PCIE_LTSSM_RECOVERY_IDLE        = 46,
+    CDNS_PCIE_LTSSM_RECOVERY_IDLE_1        = 47,
+    CDNS_PCIE_LTSSM_DISABLE_LINK        = 48,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_1        = 49,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_2        = 50,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_3        = 51,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_4        = 52,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_5        = 53,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_6        = 54,
+    CDNS_PCIE_LTSSM_DISABLE_LINK_7        = 55,
+    CDNS_PCIE_LTSSM_HOT_RESET        = 56,
+    CDNS_PCIE_LTSSM_HOT_RESET_1        = 57,
+    CDNS_PCIE_LTSSM_HOT_RESET_2        = 58,
+    CDNS_PCIE_LTSSM_HOT_RESET_3        = 59,
+    CDNS_PCIE_LTSSM_L0S_ENTRY        = 60,
+    CDNS_PCIE_LTSSM_L0S_1            = 61,
+    CDNS_PCIE_LTSSM_L0S_2            = 62,
+    CDNS_PCIE_LTSSM_L0S_3            = 63,
+    CDNS_PCIE_LTSSM_L0S_4            = 64,
+    CDNS_PCIE_LTSSM_L0S_5            = 65,
+    CDNS_PCIE_LTSSM_WAIT_FOR_LINK_TX    = 66,
+    CDNS_PCIE_LTSSM_TX_FTS_ENTRY        = 67,
+    CDNS_PCIE_LTSSM_TX_FTS_1        = 68,
+    CDNS_PCIE_LTSSM_TX_FTS_2        = 69,
+    CDNS_PCIE_LTSSM_TX_ELEC_IDLE_ST        = 70,
+    CDNS_PCIE_LTSSM_TX_ELEC_IDLE_1        = 71,
+    CDNS_PCIE_LTSSM_TX_ELEC_IDLE_2        = 72,
+    CDNS_PCIE_LTSSM_TX_ELEC_IDLE_3        = 73,
+    CDNS_PCIE_LTSSM_RECOVERY_SPEED        = 74,
+    CDNS_PCIE_LTSSM_RECOVERY_SPEED_1    = 75,
+    CDNS_PCIE_LTSSM_RECOVERY_SPEED_2    = 76,
+    CDNS_PCIE_LTSSM_RECOVERY_SPEED_3    = 77,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23 = 78,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_1 = 79,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_2 = 80,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_3 = 81,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_4 = 82,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_5 = 83,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_6 = 84,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_7 = 85,
+    CDNS_PCIE_LTSSM_POLLING_COMPLIANCE_GEN23_8 = 86,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ENTRY    = 87,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ENTRY_FROM_RECOVERY = 88,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_EXIT_1    = 89,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_EXIT    = 90,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_1    = 91,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_2    = 92,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_3    = 93,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_4    = 94,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_GEN2_5    = 95,
+    CDNS_PCIE_LTSSM_LOOPBACK_SLAVE_ACTIVE    = 96,
+    CDNS_PCIE_LTSSM_L1_ENTRY        = 97,
+    CDNS_PCIE_LTSSM_L1_1            = 98,
+    CDNS_PCIE_LTSSM_L1_2            = 99,
+    CDNS_PCIE_LTSSM_L1_3            = 100,
+    CDNS_PCIE_LTSSM_L1_4            = 101,
+    CDNS_PCIE_LTSSM_L1_IDLE            = 102,
+    CDNS_PCIE_LTSSM_L1_EXIT            = 103,
+    CDNS_PCIE_LTSSM_L2_ENTRY        = 104,
+    CDNS_PCIE_LTSSM_L2_1            = 105,
+    CDNS_PCIE_LTSSM_L2_2            = 106,
+    CDNS_PCIE_LTSSM_L2_3            = 107,
+    CDNS_PCIE_LTSSM_L2_4            = 108,
+    CDNS_PCIE_LTSSM_L2_5            = 109,
+    CDNS_PCIE_LTSSM_L2_IDLE            = 110,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY    = 111,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_1    = 112,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_2    = 113,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_3    = 114,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_4    = 115,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_5    = 116,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ENTRY_FROM_RECOVERY = 117,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_ACTIVE    = 118,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT    = 119,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT_1    = 120,
+    CDNS_PCIE_LTSSM_LOOPBACK_MASTER_EXIT_2    = 121,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE0 = 122,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE1 = 123,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE2_1 = 124,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE2_2 = 125,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE3_1 = 126,
+    CDNS_PCIE_LTSSM_RECOVERY_EQUALIZATION_PHASE3_2 = 127,
+};
+
  struct cdns_pcie_ops {
      int     (*start_link)(struct cdns_pcie *pcie);
      void    (*stop_link)(struct cdns_pcie *pcie);
@@ -87,6 +218,7 @@ struct cdns_plat_pcie_of_data {
   * @ops: Platform-specific ops to control various inputs from Cadence PCIe
   *       wrapper
   * @cdns_pcie_reg_offsets: Register bank offsets for different SoC
+ * @debug_dir: debugfs node
   */
  struct cdns_pcie {
      void __iomem                     *reg_base;
@@ -100,6 +232,7 @@ struct cdns_pcie {
      struct device_link                 **link;
      const  struct cdns_pcie_ops          *ops;
      const  struct cdns_plat_pcie_of_data *cdns_pcie_reg_offsets;
+    struct dentry                 *debug_dir;
  };
  /**
@@ -522,4 +655,16 @@ bool cdns_pcie_hpa_link_up(struct cdns_pcie *pcie);
  extern const struct dev_pm_ops cdns_pcie_pm_ops;
+#ifdef CONFIG_PCIE_CADENCE_DEBUGFS
+void cdns_pcie_debugfs_deinit(struct cdns_pcie *pci);
+void cdns_pcie_debugfs_init(struct cdns_pcie *pci);
+#else
+static inline void cdns_pcie_debugfs_deinit(struct cdns_pcie *pci)
+{
+}
+static inline void cdns_pcie_debugfs_init(struct cdns_pcie *pci)
+{
+}
+#endif
+
  #endif /* _PCIE_CADENCE_H */