RDMA/bnxt_re: Add debugfs hook in the driver

Adding support for a per device debugfs folder for exporting
some of the device specific debug information.
Added support to get QP info for now. The same folder can be
used to export other debug features in future.

Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com>
Signed-off-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://patch.msgid.link/1730428483-17841-5-git-send-email-selvin.xavier@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>

drivers/infiniband/hw/bnxt_re/Makefile

@@ -4,4 +4,5 @@ ccflags-y := -I $(srctree)/drivers/net/ethernet/broadcom/bnxt
 obj-$(CONFIG_INFINIBAND_BNXT_RE) += bnxt_re.o
 bnxt_re-y := main.o ib_verbs.o \
 	     qplib_res.o qplib_rcfw.o	\
-	     qplib_sp.o qplib_fp.o  hw_counters.o
+	     qplib_sp.o qplib_fp.o  hw_counters.o	\
+	     debugfs.o

drivers/infiniband/hw/bnxt_re/bnxt_re.h

@@ -221,6 +221,8 @@ struct bnxt_re_dev {
 	struct delayed_work dbq_pacing_work;
 	DECLARE_HASHTABLE(cq_hash, MAX_CQ_HASH_BITS);
 	DECLARE_HASHTABLE(srq_hash, MAX_SRQ_HASH_BITS);
+	struct dentry			*dbg_root;
+	struct dentry			*qp_debugfs;
 };
 
 #define to_bnxt_re_dev(ptr, member)	\

drivers/infiniband/hw/bnxt_re/debugfs.c

@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Copyright (c) 2024, Broadcom. All rights reserved.  The term
+ * Broadcom refers to Broadcom Limited and/or its subsidiaries.
+ *
+ * Description: Debugfs component of the bnxt_re driver
+ */
+
+#include <linux/debugfs.h>
+#include <linux/pci.h>
+#include <rdma/ib_addr.h>
+
+#include "bnxt_ulp.h"
+#include "roce_hsi.h"
+#include "qplib_res.h"
+#include "qplib_sp.h"
+#include "qplib_fp.h"
+#include "qplib_rcfw.h"
+#include "bnxt_re.h"
+#include "ib_verbs.h"
+#include "debugfs.h"
+
+static struct dentry *bnxt_re_debugfs_root;
+
+static inline const char *bnxt_re_qp_state_str(u8 state)
+{
+	switch (state) {
+	case CMDQ_MODIFY_QP_NEW_STATE_RESET:
+		return "RST";
+	case CMDQ_MODIFY_QP_NEW_STATE_INIT:
+		return "INIT";
+	case CMDQ_MODIFY_QP_NEW_STATE_RTR:
+		return "RTR";
+	case CMDQ_MODIFY_QP_NEW_STATE_RTS:
+		return "RTS";
+	case CMDQ_MODIFY_QP_NEW_STATE_SQE:
+		return "SQER";
+	case CMDQ_MODIFY_QP_NEW_STATE_SQD:
+		return "SQD";
+	case CMDQ_MODIFY_QP_NEW_STATE_ERR:
+		return "ERR";
+	default:
+		return "Invalid QP state";
+	}
+}
+
+static inline const char *bnxt_re_qp_type_str(u8 type)
+{
+	switch (type) {
+	case CMDQ_CREATE_QP1_TYPE_GSI: return "QP1";
+	case CMDQ_CREATE_QP_TYPE_GSI: return "QP1";
+	case CMDQ_CREATE_QP_TYPE_RC: return "RC";
+	case CMDQ_CREATE_QP_TYPE_UD: return "UD";
+	case CMDQ_CREATE_QP_TYPE_RAW_ETHERTYPE: return "RAW_ETHERTYPE";
+	default: return "Invalid transport type";
+	}
+}
+
+static ssize_t qp_info_read(struct file *filep,
+			    char __user *buffer,
+			    size_t count, loff_t *ppos)
+{
+	struct bnxt_re_qp *qp = filep->private_data;
+	char *buf;
+	int len;
+
+	if (*ppos)
+		return 0;
+
+	buf = kasprintf(GFP_KERNEL,
+			"QPN\t\t: %d\n"
+			"transport\t: %s\n"
+			"state\t\t: %s\n"
+			"mtu\t\t: %d\n"
+			"timeout\t\t: %d\n"
+			"remote QPN\t: %d\n",
+			qp->qplib_qp.id,
+			bnxt_re_qp_type_str(qp->qplib_qp.type),
+			bnxt_re_qp_state_str(qp->qplib_qp.state),
+			qp->qplib_qp.mtu,
+			qp->qplib_qp.timeout,
+			qp->qplib_qp.dest_qpn);
+	if (!buf)
+		return -ENOMEM;
+	if (count < strlen(buf)) {
+		kfree(buf);
+		return -ENOSPC;
+	}
+	len = simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
+	kfree(buf);
+	return len;
+}
+
+static const struct file_operations debugfs_qp_fops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = qp_info_read,
+};
+
+void bnxt_re_debug_add_qpinfo(struct bnxt_re_dev *rdev, struct bnxt_re_qp *qp)
+{
+	char resn[32];
+
+	sprintf(resn, "0x%x", qp->qplib_qp.id);
+	qp->dentry = debugfs_create_file(resn, 0400, rdev->qp_debugfs, qp, &debugfs_qp_fops);
+}
+
+void bnxt_re_debug_rem_qpinfo(struct bnxt_re_dev *rdev, struct bnxt_re_qp *qp)
+{
+	debugfs_remove(qp->dentry);
+}
+
+void bnxt_re_debugfs_add_pdev(struct bnxt_re_dev *rdev)
+{
+	struct pci_dev *pdev = rdev->en_dev->pdev;
+
+	rdev->dbg_root = debugfs_create_dir(dev_name(&pdev->dev), bnxt_re_debugfs_root);
+
+	rdev->qp_debugfs = debugfs_create_dir("QPs", rdev->dbg_root);
+}
+
+void bnxt_re_debugfs_rem_pdev(struct bnxt_re_dev *rdev)
+{
+	debugfs_remove_recursive(rdev->qp_debugfs);
+
+	debugfs_remove_recursive(rdev->dbg_root);
+	rdev->dbg_root = NULL;
+}
+
+void bnxt_re_register_debugfs(void)
+{
+	bnxt_re_debugfs_root = debugfs_create_dir("bnxt_re", NULL);
+}
+
+void bnxt_re_unregister_debugfs(void)
+{
+	debugfs_remove(bnxt_re_debugfs_root);
+}

drivers/infiniband/hw/bnxt_re/debugfs.h

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+/*
+ * Copyright (c) 2024, Broadcom. All rights reserved.  The term
+ * Broadcom refers to Broadcom Limited and/or its subsidiaries.
+ *
+ * Description: Debugfs header
+ */
+
+#ifndef __BNXT_RE_DEBUGFS__
+#define __BNXT_RE_DEBUGFS__
+
+void bnxt_re_debug_add_qpinfo(struct bnxt_re_dev *rdev, struct bnxt_re_qp *qp);
+void bnxt_re_debug_rem_qpinfo(struct bnxt_re_dev *rdev, struct bnxt_re_qp *qp);
+
+void bnxt_re_debugfs_add_pdev(struct bnxt_re_dev *rdev);
+void bnxt_re_debugfs_rem_pdev(struct bnxt_re_dev *rdev);
+
+void bnxt_re_register_debugfs(void);
+void bnxt_re_unregister_debugfs(void);
+
+#endif

drivers/infiniband/hw/bnxt_re/ib_verbs.c

@@ -62,6 +62,7 @@
 
 #include "bnxt_re.h"
 #include "ib_verbs.h"
+#include "debugfs.h"
 
 #include <rdma/uverbs_types.h>
 #include <rdma/uverbs_std_types.h>
@@ -997,6 +998,8 @@ int bnxt_re_destroy_qp(struct ib_qp *ib_qp, struct ib_udata *udata)
 	else if (qp->qplib_qp.type == CMDQ_CREATE_QP_TYPE_UD)
 		atomic_dec(&rdev->stats.res.ud_qp_count);
 
+	bnxt_re_debug_rem_qpinfo(rdev, qp);
+
 	ib_umem_release(qp->rumem);
 	ib_umem_release(qp->sumem);
 
@@ -1676,6 +1679,7 @@ int bnxt_re_create_qp(struct ib_qp *ib_qp, struct ib_qp_init_attr *qp_init_attr,
 		if (active_qps > rdev->stats.res.ud_qp_watermark)
 			rdev->stats.res.ud_qp_watermark = active_qps;
 	}
+	bnxt_re_debug_add_qpinfo(rdev, qp);
 
 	return 0;
 qp_destroy:

drivers/infiniband/hw/bnxt_re/ib_verbs.h

@@ -95,6 +95,7 @@ struct bnxt_re_qp {
 	struct ib_ud_header	qp1_hdr;
 	struct bnxt_re_cq	*scq;
 	struct bnxt_re_cq	*rcq;
+	struct dentry		*dentry;
 };
 
 struct bnxt_re_cq {

drivers/infiniband/hw/bnxt_re/main.c

@@ -67,6 +67,7 @@
 #include <rdma/bnxt_re-abi.h>
 #include "bnxt.h"
 #include "hw_counters.h"
+#include "debugfs.h"
 
 static char version[] =
 		BNXT_RE_DESC "\n";
@@ -1863,6 +1864,8 @@ static void bnxt_re_dev_uninit(struct bnxt_re_dev *rdev, u8 op_type)
 	u8 type;
 	int rc;
 
+	bnxt_re_debugfs_rem_pdev(rdev);
+
 	if (test_and_clear_bit(BNXT_RE_FLAG_QOS_WORK_REG, &rdev->flags))
 		cancel_delayed_work_sync(&rdev->worker);
 
@@ -2063,6 +2066,8 @@ static int bnxt_re_dev_init(struct bnxt_re_dev *rdev, u8 op_type)
 	if (rdev->chip_ctx->modes.toggle_bits & BNXT_QPLIB_SRQ_TOGGLE_BIT)
 		hash_init(rdev->srq_hash);
 
+	bnxt_re_debugfs_add_pdev(rdev);
+
 	return 0;
 free_sctx:
 	bnxt_re_net_stats_ctx_free(rdev, rdev->qplib_ctx.stats.fw_id);
@@ -2389,18 +2394,24 @@ static int __init bnxt_re_mod_init(void)
 	int rc;
 
 	pr_info("%s: %s", ROCE_DRV_MODULE_NAME, version);
+	bnxt_re_register_debugfs();
+
 	rc = auxiliary_driver_register(&bnxt_re_driver);
 	if (rc) {
 		pr_err("%s: Failed to register auxiliary driver\n",
 			ROCE_DRV_MODULE_NAME);
-		return rc;
+		goto err_debug;
 	}
 	return 0;
+err_debug:
+	bnxt_re_unregister_debugfs();
+	return rc;
 }
 
 static void __exit bnxt_re_mod_exit(void)
 {
 	auxiliary_driver_unregister(&bnxt_re_driver);
+	bnxt_re_unregister_debugfs();
 }
 
 module_init(bnxt_re_mod_init);