Add PCIe hardware statistics support to the fbnic driver. These stats
provide insight into PCIe transaction performance and error conditions.

Which includes, read/write and completion TLP counts and DWORD counts and
debug counters for tag, completion credit and NP credit exhaustion

The stats are exposed via debugfs and can be used to monitor PCIe
performance and debug PCIe issues.

Signed-off-by: Sanman Pradhan <sanman.p211993@gmail.com>
---
v5:
	- Add missing fbnic_dbg_init, fbnic_dbg_exit, fbnic_dbg_fbd_init and fbnic_dbg_fbd_exit functions
	- Add missing entry in fbnic.h
	- Tested on 1-NIC 2-Host system
		- Test Logs:
				Without ping <remote_host>
					# cat /sys/kernel/debug/fbnic/0000\:01\:00.0/pcie_stats
					ob_rd_tlp: 88724
					ob_rd_dword: 1363273
					ob_wr_tlp: 980410
					ob_wr_dword: 105006453
					ob_cpl_tlp: 98665
					ob_cpl_dword: 1363273
					ob_rd_no_tag: 0
					ob_rd_no_cpl_cred: 0
					ob_rd_no_np_cred: 0
				With ping <remote_host>
					# cat /sys/kernel/debug/fbnic/0000\:01\:00.0/pcie_stats
					ob_rd_tlp: 114081
					ob_rd_dword: 1902295
					ob_wr_tlp: 1098457
					ob_wr_dword: 112936622
					ob_cpl_tlp: 128409
					ob_cpl_dword: 1902295
					ob_rd_no_tag: 0
					ob_rd_no_cpl_cred: 0
					ob_rd_no_np_cred: 0
v4:
	- https://patchwork.kernel.org/project/netdevbpf/patch/20241109025905.1531196-1-sanman.p211993@gmail.com/
	- Fix indentations
	- Adding missing updates for previous versions
v3:
	- https://patchwork.kernel.org/project/netdevbpf/patch/20241108204640.3165724-1-sanman.p211993@gmail.com/
	- Moved PCIe stats to debugfs
v2:
	- https://patchwork.kernel.org/project/netdevbpf/patch/20241107020555.321245-1-sanman.p211993@gmail.com/
	- Removed unnecessary code blocks
	- Rephrased the commit message
v1:
	- https://patchwork.kernel.org/project/netdevbpf/patch/20241106002625.1857904-1-sanman.p211993@gmail.com/
---
 .../device_drivers/ethernet/meta/fbnic.rst    |  26 ++++
 drivers/net/ethernet/meta/fbnic/Makefile      |   1 +
 drivers/net/ethernet/meta/fbnic/fbnic.h       |   6 +
 drivers/net/ethernet/meta/fbnic/fbnic_csr.h   |  37 ++++++
 .../net/ethernet/meta/fbnic/fbnic_debugfs.c   |  68 +++++++++++
 .../net/ethernet/meta/fbnic/fbnic_devlink.c   |   4 +
 .../net/ethernet/meta/fbnic/fbnic_hw_stats.c  | 114 ++++++++++++++++++
 .../net/ethernet/meta/fbnic/fbnic_hw_stats.h  |  12 ++
 .../net/ethernet/meta/fbnic/fbnic_netdev.c    |   3 +
 drivers/net/ethernet/meta/fbnic/fbnic_pci.c   |   8 +-
 10 files changed, 278 insertions(+), 1 deletion(-)
 create mode 100644 drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c

diff --git a/Documentation/networking/device_drivers/ethernet/meta/fbnic.rst b/Documentation/networking/device_drivers/ethernet/meta/fbnic.rst
index 32ff114f5c26..13ebcdbb5f22 100644
--- a/Documentation/networking/device_drivers/ethernet/meta/fbnic.rst
+++ b/Documentation/networking/device_drivers/ethernet/meta/fbnic.rst
@@ -27,3 +27,29 @@ driver takes over.
 devlink dev info provides version information for all three components. In
 addition to the version the hg commit hash of the build is included as a
 separate entry.
+
+PCIe Statistics
+---------------
+
+The fbnic driver exposes PCIe hardware performance statistics through debugfs
+(``pcie_stats``). These statistics provide insights into PCIe transaction
+behavior and potential performance bottlenecks.
+
+Statistics Categories
+
+1. PCIe Transaction Counters:
+
+   These counters track PCIe transaction activity:
+        - pcie_ob_rd_tlp: Outbound read Transaction Layer Packets count
+        - pcie_ob_rd_dword: DWORDs transferred in outbound read transactions
+        - pcie_ob_wr_tlp: Outbound write Transaction Layer Packets count
+        - pcie_ob_wr_dword: DWORDs transferred in outbound write transactions
+        - pcie_ob_cpl_tlp: Outbound completion TLP count
+        - pcie_ob_cpl_dword: DWORDs transferred in outbound completion TLPs
+
+2. PCIe Resource Monitoring:
+
+   These counters indicate PCIe resource exhaustion events:
+        - pcie_ob_rd_no_tag: Read requests dropped due to tag unavailability
+        - pcie_ob_rd_no_cpl_cred: Read requests dropped due to completion credit exhaustion
+        - pcie_ob_rd_no_np_cred: Read requests dropped due to non-posted credit exhaustion
diff --git a/drivers/net/ethernet/meta/fbnic/Makefile b/drivers/net/ethernet/meta/fbnic/Makefile
index 425e8b801265..7109d6390b0d 100644
--- a/drivers/net/ethernet/meta/fbnic/Makefile
+++ b/drivers/net/ethernet/meta/fbnic/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_FBNIC) += fbnic.o

 fbnic-y := fbnic_csr.o \
 	   fbnic_devlink.o \
+	   fbnic_debugfs.o \
 	   fbnic_ethtool.o \
 	   fbnic_fw.o \
 	   fbnic_hw_stats.o \
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic.h b/drivers/net/ethernet/meta/fbnic/fbnic.h
index 7d5efbf32408..f2c641174f63 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic.h
@@ -19,6 +19,7 @@
 struct fbnic_dev {
 	struct device *dev;
 	struct net_device *netdev;
+	struct dentry *dbg_fbd;
 	struct device *hwmon;

 	u32 __iomem *uc_addr0;
@@ -158,6 +159,11 @@ void fbnic_get_fw_ver_commit_str(struct fbnic_dev *fbd, char *fw_version,
 void fbnic_csr_get_regs(struct fbnic_dev *fbd, u32 *data, u32 *regs_version);
 int fbnic_csr_regs_len(struct fbnic_dev *fbd);

+void fbnic_dbg_fbd_init(struct fbnic_dev *fbd);
+void fbnic_dbg_fbd_exit(struct fbnic_dev *fbd);
+void fbnic_dbg_init(void);
+void fbnic_dbg_exit(void);
+
 enum fbnic_boards {
 	fbnic_board_asic
 };
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_csr.h b/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
index e78745332d82..463fd5d54d35 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_csr.h
@@ -917,6 +917,43 @@ enum {
 #define FBNIC_MAX_QUEUES		128
 #define FBNIC_CSR_END_QUEUE	(0x40000 + 0x400 * FBNIC_MAX_QUEUES - 1)

+/* PUL User Registers*/
+#define FBNIC_PUL_USER_OB_RD_TLP_CNT_31_0 \
+					0x3106e		/* 0xc41b8 */
+#define FBNIC_PUL_USER_OB_RD_DWORD_CNT_31_0 \
+					0x31070		/* 0xc41c0 */
+#define FBNIC_PUL_USER_OB_RD_DWORD_CNT_63_32 \
+					0x31071		/* 0xc41c4 */
+#define FBNIC_PUL_USER_OB_WR_TLP_CNT_31_0 \
+					0x31072		/* 0xc41c8 */
+#define FBNIC_PUL_USER_OB_WR_TLP_CNT_63_32 \
+					0x31073		/* 0xc41cc */
+#define FBNIC_PUL_USER_OB_WR_DWORD_CNT_31_0 \
+					0x31074		/* 0xc41d0 */
+#define FBNIC_PUL_USER_OB_WR_DWORD_CNT_63_32 \
+					0x31075		/* 0xc41d4 */
+#define FBNIC_PUL_USER_OB_CPL_TLP_CNT_31_0 \
+					0x31076		/* 0xc41d8 */
+#define FBNIC_PUL_USER_OB_CPL_TLP_CNT_63_32 \
+					0x31077		/* 0xc41dc */
+#define FBNIC_PUL_USER_OB_CPL_DWORD_CNT_31_0 \
+					0x31078		/* 0xc41e0 */
+#define FBNIC_PUL_USER_OB_CPL_DWORD_CNT_63_32 \
+					0x31079		/* 0xc41e4 */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_CPL_CRED_31_0 \
+					0x3107a		/* 0xc41e8 */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_CPL_CRED_63_32 \
+					0x3107b		/* 0xc41ec */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_TAG_31_0 \
+					0x3107c		/* 0xc41f0 */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_TAG_63_32 \
+					0x3107d		/* 0xc41f4 */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_NP_CRED_31_0 \
+					0x3107e		/* 0xc41f8 */
+#define FBNIC_PUL_USER_OB_RD_DBG_CNT_NP_CRED_63_32 \
+					0x3107f		/* 0xc41fc */
+#define FBNIC_CSR_END_PUL_USER	0x31080	/* CSR section delimiter */
+
 /* BAR 4 CSRs */

 /* The IPC mailbox consists of 32 mailboxes, with each mailbox consisting
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c b/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c
new file mode 100644
index 000000000000..a2f424124a86
--- /dev/null
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) Meta Platforms, Inc. and affiliates. */
+
+#include <linux/debugfs.h>
+#include <linux/pci.h>
+#include <linux/rtnetlink.h>
+#include <linux/seq_file.h>
+#include "fbnic.h"
+
+static struct dentry *fbnic_dbg_root;
+
+static int fbnic_dbg_pcie_stats_show(struct seq_file *s, void *v)
+{
+	struct fbnic_dev *fbd = s->private;
+
+	rtnl_lock();
+
+	fbnic_get_hw_stats(fbd);
+
+	seq_printf(s, "ob_rd_tlp: %llu\n", fbd->hw_stats.pcie.ob_rd_tlp.value);
+	seq_printf(s, "ob_rd_dword: %llu\n",
+		   fbd->hw_stats.pcie.ob_rd_dword.value);
+	seq_printf(s, "ob_wr_tlp: %llu\n", fbd->hw_stats.pcie.ob_wr_tlp.value);
+	seq_printf(s, "ob_wr_dword: %llu\n",
+		   fbd->hw_stats.pcie.ob_wr_dword.value);
+	seq_printf(s, "ob_cpl_tlp: %llu\n",
+		   fbd->hw_stats.pcie.ob_cpl_tlp.value);
+	seq_printf(s, "ob_cpl_dword: %llu\n",
+		   fbd->hw_stats.pcie.ob_cpl_dword.value);
+	seq_printf(s, "ob_rd_no_tag: %llu\n",
+		   fbd->hw_stats.pcie.ob_rd_no_tag.value);
+	seq_printf(s, "ob_rd_no_cpl_cred: %llu\n",
+		   fbd->hw_stats.pcie.ob_rd_no_cpl_cred.value);
+	seq_printf(s, "ob_rd_no_np_cred: %llu\n",
+		   fbd->hw_stats.pcie.ob_rd_no_np_cred.value);
+
+	rtnl_unlock();
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(fbnic_dbg_pcie_stats);
+
+void fbnic_dbg_fbd_init(struct fbnic_dev *fbd)
+{
+	struct pci_dev *pdev = to_pci_dev(fbd->dev);
+	const char *name = pci_name(pdev);
+
+	fbd->dbg_fbd = debugfs_create_dir(name, fbnic_dbg_root);
+	debugfs_create_file("pcie_stats", 0400, fbd->dbg_fbd, fbd,
+			    &fbnic_dbg_pcie_stats_fops);
+}
+
+void fbnic_dbg_fbd_exit(struct fbnic_dev *fbd)
+{
+	debugfs_remove_recursive(fbd->dbg_fbd);
+	fbd->dbg_fbd = NULL;
+}
+
+void fbnic_dbg_init(void)
+{
+	fbnic_dbg_root = debugfs_create_dir(fbnic_driver_name, NULL);
+}
+
+void fbnic_dbg_exit(void)
+{
+	debugfs_remove_recursive(fbnic_dbg_root);
+	fbnic_dbg_root = NULL;
+}
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_devlink.c b/drivers/net/ethernet/meta/fbnic/fbnic_devlink.c
index 0072d612215e..10b27fd07069 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_devlink.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_devlink.c
@@ -117,6 +117,8 @@ void fbnic_devlink_free(struct fbnic_dev *fbd)
 {
 	struct devlink *devlink = priv_to_devlink(fbd);

+	fbnic_dbg_fbd_exit(fbd);
+
 	devlink_free(devlink);
 }

@@ -145,6 +147,8 @@ struct fbnic_dev *fbnic_devlink_alloc(struct pci_dev *pdev)

 	fbd->mac_addr_boundary = FBNIC_RPC_TCAM_MACDA_DEFAULT_BOUNDARY;

+	fbnic_dbg_fbd_init(fbd);
+
 	return fbd;
 }

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c
index a0acc7606aa1..eb19b49fe306 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.c
@@ -25,3 +25,117 @@ u64 fbnic_stat_rd64(struct fbnic_dev *fbd, u32 reg, u32 offset)
 	 */
 	return ((u64)upper << 32);
 }
+
+static void fbnic_hw_stat_rst64(struct fbnic_dev *fbd, u32 reg, s32 offset,
+				struct fbnic_stat_counter *stat)
+{
+	/* Record initial counter values and compute deltas from there to ensure
+	 * stats start at 0 after reboot/reset. This avoids exposing absolute
+	 * hardware counter values to userspace.
+	 */
+	stat->u.old_reg_value_64 = fbnic_stat_rd64(fbd, reg, offset);
+}
+
+static void fbnic_hw_stat_rd64(struct fbnic_dev *fbd, u32 reg, s32 offset,
+			       struct fbnic_stat_counter *stat)
+{
+	u64 new_reg_value;
+
+	new_reg_value = fbnic_stat_rd64(fbd, reg, offset);
+	stat->value += new_reg_value - stat->u.old_reg_value_64;
+	stat->u.old_reg_value_64 = new_reg_value;
+}
+
+static void fbnic_reset_pcie_stats_asic(struct fbnic_dev *fbd,
+					struct fbnic_pcie_stats *pcie)
+{
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_RD_TLP_CNT_31_0,
+			    1,
+			    &pcie->ob_rd_tlp);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_RD_DWORD_CNT_31_0,
+			    1,
+			    &pcie->ob_rd_dword);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_CPL_TLP_CNT_31_0,
+			    1,
+			    &pcie->ob_cpl_tlp);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_CPL_DWORD_CNT_31_0,
+			    1,
+			    &pcie->ob_cpl_dword);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_WR_TLP_CNT_31_0,
+			    1,
+			    &pcie->ob_wr_tlp);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_WR_DWORD_CNT_31_0,
+			    1,
+			    &pcie->ob_wr_dword);
+
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_RD_DBG_CNT_TAG_31_0,
+			    1,
+			    &pcie->ob_rd_no_tag);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_RD_DBG_CNT_CPL_CRED_31_0,
+			    1,
+			    &pcie->ob_rd_no_cpl_cred);
+	fbnic_hw_stat_rst64(fbd,
+			    FBNIC_PUL_USER_OB_RD_DBG_CNT_NP_CRED_31_0,
+			    1,
+			    &pcie->ob_rd_no_np_cred);
+}
+
+static void fbnic_get_pcie_stats_asic64(struct fbnic_dev *fbd,
+					struct fbnic_pcie_stats *pcie)
+{
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_RD_TLP_CNT_31_0,
+			   1,
+			   &pcie->ob_rd_tlp);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_RD_DWORD_CNT_31_0,
+			   1,
+			   &pcie->ob_rd_dword);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_WR_TLP_CNT_31_0,
+			   1,
+			   &pcie->ob_wr_tlp);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_WR_DWORD_CNT_31_0,
+			   1,
+			   &pcie->ob_wr_dword);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_CPL_TLP_CNT_31_0,
+			   1,
+			   &pcie->ob_cpl_tlp);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_CPL_DWORD_CNT_31_0,
+			   1,
+			   &pcie->ob_cpl_dword);
+
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_RD_DBG_CNT_TAG_31_0,
+			   1,
+			   &pcie->ob_rd_no_tag);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_RD_DBG_CNT_CPL_CRED_31_0,
+			   1,
+			   &pcie->ob_rd_no_cpl_cred);
+	fbnic_hw_stat_rd64(fbd,
+			   FBNIC_PUL_USER_OB_RD_DBG_CNT_NP_CRED_31_0,
+			   1,
+			   &pcie->ob_rd_no_np_cred);
+}
+
+void fbnic_reset_hw_stats(struct fbnic_dev *fbd)
+{
+	fbnic_reset_pcie_stats_asic(fbd, &fbd->hw_stats.pcie);
+}
+
+void fbnic_get_hw_stats(struct fbnic_dev *fbd)
+{
+	fbnic_get_pcie_stats_asic64(fbd, &fbd->hw_stats.pcie);
+}
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.h b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.h
index 30348904b510..036cc065a857 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.h
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_hw_stats.h
@@ -31,10 +31,22 @@ struct fbnic_mac_stats {
 	struct fbnic_eth_mac_stats eth_mac;
 };

+struct fbnic_pcie_stats {
+	struct fbnic_stat_counter ob_rd_tlp, ob_rd_dword;
+	struct fbnic_stat_counter ob_wr_tlp, ob_wr_dword;
+	struct fbnic_stat_counter ob_cpl_tlp, ob_cpl_dword;
+
+	struct fbnic_stat_counter ob_rd_no_tag;
+	struct fbnic_stat_counter ob_rd_no_cpl_cred;
+	struct fbnic_stat_counter ob_rd_no_np_cred;
+};
+
 struct fbnic_hw_stats {
 	struct fbnic_mac_stats mac;
+	struct fbnic_pcie_stats pcie;
 };

 u64 fbnic_stat_rd64(struct fbnic_dev *fbd, u32 reg, u32 offset);

+void fbnic_reset_hw_stats(struct fbnic_dev *fbd);
 void fbnic_get_hw_stats(struct fbnic_dev *fbd);
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
index fc7d80db5fa6..04077649161b 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_netdev.c
@@ -628,6 +628,9 @@ struct net_device *fbnic_netdev_alloc(struct fbnic_dev *fbd)

 	fbnic_reset_queues(fbn, default_queues, default_queues);

+	/* Capture snapshot of hardware stats so netdev can calculate delta */
+	fbnic_reset_hw_stats(fbd);
+
 	fbnic_reset_indir_tbl(fbn);
 	fbnic_rss_key_fill(fbn->rss_key);
 	fbnic_rss_init_en_mask(fbn);
diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
index 2de5a6fde7e8..5c485e9f3469 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
@@ -552,9 +552,13 @@ static int __init fbnic_init_module(void)
 {
 	int err;

+	fbnic_dbg_init();
+
 	err = pci_register_driver(&fbnic_driver);
-	if (err)
+	if (err) {
+		fbnic_dbg_exit();
 		goto out;
+	}

 	pr_info(DRV_SUMMARY " (%s)", fbnic_driver.name);
 out:
@@ -570,5 +574,7 @@ module_init(fbnic_init_module);
 static void __exit fbnic_exit_module(void)
 {
 	pci_unregister_driver(&fbnic_driver);
+
+	fbnic_dbg_exit();
 }
 module_exit(fbnic_exit_module);
--
2.43.5

> @@ -145,6 +147,8 @@ struct fbnic_dev *fbnic_devlink_alloc(struct pci_dev *pdev)
> 
>  	fbd->mac_addr_boundary = FBNIC_RPC_TCAM_MACDA_DEFAULT_BOUNDARY;
> 
> +	fbnic_dbg_fbd_init(fbd);
> +
>  	return fbd;
>  }

I thought it was odd that you create debugfs files in
fbnic_devlink_alloc(). But when you look at that function, it is
actually badly named, it is a collection of random initialisation, of
which devlink is just one.

I would suggest you call fbnic_dbg_fbd_init() in probe, like any
normal driver would.

	Andrew

On Mon, Nov 11, 2024 at 11:57:15AM -0800, Sanman Pradhan wrote:
> Add PCIe hardware statistics support to the fbnic driver. These stats
> provide insight into PCIe transaction performance and error conditions.
> 
> Which includes, read/write and completion TLP counts and DWORD counts and
> debug counters for tag, completion credit and NP credit exhaustion
> 
> The stats are exposed via debugfs and can be used to monitor PCIe
> performance and debug PCIe issues.
> 
> Signed-off-by: Sanman Pradhan <sanman.p211993@gmail.com>
> ---
> v5:
> 	- Add missing fbnic_dbg_init, fbnic_dbg_exit, fbnic_dbg_fbd_init and fbnic_dbg_fbd_exit functions
> 	- Add missing entry in fbnic.h
> 	- Tested on 1-NIC 2-Host system
> 		- Test Logs:
> 				Without ping <remote_host>
> 					# cat /sys/kernel/debug/fbnic/0000\:01\:00.0/pcie_stats
> 					ob_rd_tlp: 88724
> 					ob_rd_dword: 1363273
> 					ob_wr_tlp: 980410
> 					ob_wr_dword: 105006453
> 					ob_cpl_tlp: 98665
> 					ob_cpl_dword: 1363273
> 					ob_rd_no_tag: 0
> 					ob_rd_no_cpl_cred: 0
> 					ob_rd_no_np_cred: 0
> 				With ping <remote_host>
> 					# cat /sys/kernel/debug/fbnic/0000\:01\:00.0/pcie_stats
> 					ob_rd_tlp: 114081
> 					ob_rd_dword: 1902295
> 					ob_wr_tlp: 1098457
> 					ob_wr_dword: 112936622
> 					ob_cpl_tlp: 128409
> 					ob_cpl_dword: 1902295
> 					ob_rd_no_tag: 0
> 					ob_rd_no_cpl_cred: 0
> 					ob_rd_no_np_cred: 0
> v4:
> 	- https://patchwork.kernel.org/project/netdevbpf/patch/20241109025905.1531196-1-sanman.p211993@gmail.com/
> 	- Fix indentations
> 	- Adding missing updates for previous versions
> v3:
> 	- https://patchwork.kernel.org/project/netdevbpf/patch/20241108204640.3165724-1-sanman.p211993@gmail.com/
> 	- Moved PCIe stats to debugfs
> v2:
> 	- https://patchwork.kernel.org/project/netdevbpf/patch/20241107020555.321245-1-sanman.p211993@gmail.com/
> 	- Removed unnecessary code blocks
> 	- Rephrased the commit message
> v1:
> 	- https://patchwork.kernel.org/project/netdevbpf/patch/20241106002625.1857904-1-sanman.p211993@gmail.com/
> ---
>  .../device_drivers/ethernet/meta/fbnic.rst    |  26 ++++
>  drivers/net/ethernet/meta/fbnic/Makefile      |   1 +
>  drivers/net/ethernet/meta/fbnic/fbnic.h       |   6 +
>  drivers/net/ethernet/meta/fbnic/fbnic_csr.h   |  37 ++++++
>  .../net/ethernet/meta/fbnic/fbnic_debugfs.c   |  68 +++++++++++
>  .../net/ethernet/meta/fbnic/fbnic_devlink.c   |   4 +
>  .../net/ethernet/meta/fbnic/fbnic_hw_stats.c  | 114 ++++++++++++++++++
>  .../net/ethernet/meta/fbnic/fbnic_hw_stats.h  |  12 ++
>  .../net/ethernet/meta/fbnic/fbnic_netdev.c    |   3 +
>  drivers/net/ethernet/meta/fbnic/fbnic_pci.c   |   8 +-
>  10 files changed, 278 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/net/ethernet/meta/fbnic/fbnic_debugfs.c

Just FYI this patch does not seem to apply to net-next/main. Did you
rebase?