net: mana: Enable debugfs files for MANA device

Implement debugfs in MANA driver to be able to view RX,TX,EQ queue
specific attributes and dump their gdma queues.
These dumps can be used by other userspace utilities to improve
debuggability and troubleshooting

Following files are added in debugfs:

/sys/kernel/debug/mana/
|-------------- 1
    |--------------- EQs
    |                 |------- eq0
    |                 |          |---head
    |                 |          |---tail
    |                 |          |---eq_dump
    |                 |------- eq1
    |                 .
    |                 .
    |
    |--------------- adapter-MTU
    |--------------- vport0
                      |------- RX-0
                      |          |---cq_budget
                      |          |---cq_dump
                      |          |---cq_head
                      |          |---cq_tail
                      |          |---rq_head
                      |          |---rq_nbuf
                      |          |---rq_tail
                      |          |---rxq_dump
                      |------- RX-1
                      .
                      .
                      |------- TX-0
                      |          |---cq_budget
                      |          |---cq_dump
                      |          |---cq_head
                      |          |---cq_tail
                      |          |---sq_head
                      |          |---sq_pend_skb_qlen
                      |          |---sq_tail
                      |          |---txq_dump
                      |------- TX-1
                      .
                      .

Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/microsoft/mana/gdma_main.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
 /* Copyright (c) 2021, Microsoft Corporation. */
 
+#include <linux/debugfs.h>
 #include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/utsname.h>
@@ -8,6 +9,8 @@
 
 #include <net/mana/mana.h>
 
+struct dentry *mana_debugfs_root;
+
 static u32 mana_gd_r32(struct gdma_context *g, u64 offset)
 {
 	return readl(g->bar0_va + offset);
@@ -1516,6 +1519,12 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	gc->bar0_va = bar0_va;
 	gc->dev = &pdev->dev;
 
+	if (gc->is_pf)
+		gc->mana_pci_debugfs = debugfs_create_dir("0", mana_debugfs_root);
+	else
+		gc->mana_pci_debugfs = debugfs_create_dir(pci_slot_name(pdev->slot),
+							  mana_debugfs_root);
+
 	err = mana_gd_setup(pdev);
 	if (err)
 		goto unmap_bar;
@@ -1529,6 +1538,13 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 cleanup_gd:
 	mana_gd_cleanup(pdev);
 unmap_bar:
+	/*
+	 * at this point we know that the other debugfs child dir/files
+	 * are either not yet created or are already cleaned up.
+	 * The pci debugfs folder clean-up now, will only be cleaning up
+	 * adapter-MTU file and apc->mana_pci_debugfs folder.
+	 */
+	debugfs_remove_recursive(gc->mana_pci_debugfs);
 	pci_iounmap(pdev, bar0_va);
 free_gc:
 	pci_set_drvdata(pdev, NULL);
@@ -1549,6 +1565,8 @@ static void mana_gd_remove(struct pci_dev *pdev)
 
 	mana_gd_cleanup(pdev);
 
+	debugfs_remove_recursive(gc->mana_pci_debugfs);
+
 	pci_iounmap(pdev, gc->bar0_va);
 
 	vfree(gc);
@@ -1600,6 +1618,8 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
 
 	mana_gd_cleanup(pdev);
 
+	debugfs_remove_recursive(gc->mana_pci_debugfs);
+
 	pci_disable_device(pdev);
 }
 
@@ -1619,7 +1639,28 @@ static struct pci_driver mana_driver = {
 	.shutdown	= mana_gd_shutdown,
 };
 
-module_pci_driver(mana_driver);
+static int __init mana_driver_init(void)
+{
+	int err;
+
+	mana_debugfs_root = debugfs_create_dir("mana", NULL);
+
+	err = pci_register_driver(&mana_driver);
+	if (err)
+		debugfs_remove(mana_debugfs_root);
+
+	return err;
+}
+
+static void __exit mana_driver_exit(void)
+{
+	debugfs_remove(mana_debugfs_root);
+
+	pci_unregister_driver(&mana_driver);
+}
+
+module_init(mana_driver_init);
+module_exit(mana_driver_exit);
 
 MODULE_DEVICE_TABLE(pci, mana_id_table);
 

drivers/net/ethernet/microsoft/mana/mana_en.c

@@ -3,6 +3,7 @@
 
 #include <uapi/linux/bpf.h>
 
+#include <linux/debugfs.h>
 #include <linux/inetdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/ethtool.h>
@@ -30,6 +31,21 @@ static void mana_adev_idx_free(int idx)
 	ida_free(&mana_adev_ida, idx);
 }
 
+static ssize_t mana_dbg_q_read(struct file *filp, char __user *buf, size_t count,
+			       loff_t *pos)
+{
+	struct gdma_queue *gdma_q = filp->private_data;
+
+	return simple_read_from_buffer(buf, count, pos, gdma_q->queue_mem_ptr,
+				       gdma_q->queue_size);
+}
+
+static const struct file_operations mana_dbg_q_fops = {
+	.owner  = THIS_MODULE,
+	.open   = simple_open,
+	.read   = mana_dbg_q_read,
+};
+
 /* Microsoft Azure Network Adapter (MANA) functions */
 
 static int mana_open(struct net_device *ndev)
@@ -721,6 +737,13 @@ static const struct net_device_ops mana_devops = {
 
 static void mana_cleanup_port_context(struct mana_port_context *apc)
 {
+	/*
+	 * at this point all dir/files under the vport directory
+	 * are already cleaned up.
+	 * We are sure the apc->mana_port_debugfs remove will not
+	 * cause any freed memory access issues
+	 */
+	debugfs_remove(apc->mana_port_debugfs);
 	kfree(apc->rxqs);
 	apc->rxqs = NULL;
 }
@@ -943,6 +966,8 @@ static int mana_query_device_cfg(struct mana_context *ac, u32 proto_major_ver,
 	else
 		gc->adapter_mtu = ETH_FRAME_LEN;
 
+	debugfs_create_u16("adapter-MTU", 0400, gc->mana_pci_debugfs, &gc->adapter_mtu);
+
 	return 0;
 }
 
@@ -1228,6 +1253,8 @@ static void mana_destroy_eq(struct mana_context *ac)
 	if (!ac->eqs)
 		return;
 
+	debugfs_remove_recursive(ac->mana_eqs_debugfs);
+
 	for (i = 0; i < gc->max_num_queues; i++) {
 		eq = ac->eqs[i].eq;
 		if (!eq)
@@ -1240,6 +1267,18 @@ static void mana_destroy_eq(struct mana_context *ac)
 	ac->eqs = NULL;
 }
 
+static void mana_create_eq_debugfs(struct mana_context *ac, int i)
+{
+	struct mana_eq eq = ac->eqs[i];
+	char eqnum[32];
+
+	sprintf(eqnum, "eq%d", i);
+	eq.mana_eq_debugfs = debugfs_create_dir(eqnum, ac->mana_eqs_debugfs);
+	debugfs_create_u32("head", 0400, eq.mana_eq_debugfs, &eq.eq->head);
+	debugfs_create_u32("tail", 0400, eq.mana_eq_debugfs, &eq.eq->tail);
+	debugfs_create_file("eq_dump", 0400, eq.mana_eq_debugfs, eq.eq, &mana_dbg_q_fops);
+}
+
 static int mana_create_eq(struct mana_context *ac)
 {
 	struct gdma_dev *gd = ac->gdma_dev;
@@ -1260,11 +1299,14 @@ static int mana_create_eq(struct mana_context *ac)
 	spec.eq.context = ac->eqs;
 	spec.eq.log2_throttle_limit = LOG2_EQ_THROTTLE;
 
+	ac->mana_eqs_debugfs = debugfs_create_dir("EQs", gc->mana_pci_debugfs);
+
 	for (i = 0; i < gc->max_num_queues; i++) {
 		spec.eq.msix_index = (i + 1) % gc->num_msix_usable;
 		err = mana_gd_create_mana_eq(gd, &spec, &ac->eqs[i].eq);
 		if (err)
 			goto out;
+		mana_create_eq_debugfs(ac, i);
 	}
 
 	return 0;
@@ -1871,6 +1913,8 @@ static void mana_destroy_txq(struct mana_port_context *apc)
 		return;
 
 	for (i = 0; i < apc->num_queues; i++) {
+		debugfs_remove_recursive(apc->tx_qp[i].mana_tx_debugfs);
+
 		napi = &apc->tx_qp[i].tx_cq.napi;
 		if (apc->tx_qp[i].txq.napi_initialized) {
 			napi_synchronize(napi);
@@ -1889,6 +1933,31 @@ static void mana_destroy_txq(struct mana_port_context *apc)
 	apc->tx_qp = NULL;
 }
 
+static void mana_create_txq_debugfs(struct mana_port_context *apc, int idx)
+{
+	struct mana_tx_qp *tx_qp = &apc->tx_qp[idx];
+	char qnum[32];
+
+	sprintf(qnum, "TX-%d", idx);
+	tx_qp->mana_tx_debugfs = debugfs_create_dir(qnum, apc->mana_port_debugfs);
+	debugfs_create_u32("sq_head", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->txq.gdma_sq->head);
+	debugfs_create_u32("sq_tail", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->txq.gdma_sq->tail);
+	debugfs_create_u32("sq_pend_skb_qlen", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->txq.pending_skbs.qlen);
+	debugfs_create_u32("cq_head", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->tx_cq.gdma_cq->head);
+	debugfs_create_u32("cq_tail", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->tx_cq.gdma_cq->tail);
+	debugfs_create_u32("cq_budget", 0400, tx_qp->mana_tx_debugfs,
+			   &tx_qp->tx_cq.budget);
+	debugfs_create_file("txq_dump", 0400, tx_qp->mana_tx_debugfs,
+			    tx_qp->txq.gdma_sq, &mana_dbg_q_fops);
+	debugfs_create_file("cq_dump", 0400, tx_qp->mana_tx_debugfs,
+			    tx_qp->tx_cq.gdma_cq, &mana_dbg_q_fops);
+}
+
 static int mana_create_txq(struct mana_port_context *apc,
 			   struct net_device *net)
 {
@@ -2000,6 +2069,8 @@ static int mana_create_txq(struct mana_port_context *apc,
 
 		gc->cq_table[cq->gdma_id] = cq->gdma_cq;
 
+		mana_create_txq_debugfs(apc, i);
+
 		netif_napi_add_tx(net, &cq->napi, mana_poll);
 		napi_enable(&cq->napi);
 		txq->napi_initialized = true;
@@ -2027,6 +2098,8 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
 	if (!rxq)
 		return;
 
+	debugfs_remove_recursive(rxq->mana_rx_debugfs);
+
 	napi = &rxq->rx_cq.napi;
 
 	if (napi_initialized) {
@@ -2308,6 +2381,28 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
 	return NULL;
 }
 
+static void mana_create_rxq_debugfs(struct mana_port_context *apc, int idx)
+{
+	struct mana_rxq *rxq;
+	char qnum[32];
+
+	rxq = apc->rxqs[idx];
+
+	sprintf(qnum, "RX-%d", idx);
+	rxq->mana_rx_debugfs = debugfs_create_dir(qnum, apc->mana_port_debugfs);
+	debugfs_create_u32("rq_head", 0400, rxq->mana_rx_debugfs, &rxq->gdma_rq->head);
+	debugfs_create_u32("rq_tail", 0400, rxq->mana_rx_debugfs, &rxq->gdma_rq->tail);
+	debugfs_create_u32("rq_nbuf", 0400, rxq->mana_rx_debugfs, &rxq->num_rx_buf);
+	debugfs_create_u32("cq_head", 0400, rxq->mana_rx_debugfs,
+			   &rxq->rx_cq.gdma_cq->head);
+	debugfs_create_u32("cq_tail", 0400, rxq->mana_rx_debugfs,
+			   &rxq->rx_cq.gdma_cq->tail);
+	debugfs_create_u32("cq_budget", 0400, rxq->mana_rx_debugfs, &rxq->rx_cq.budget);
+	debugfs_create_file("rxq_dump", 0400, rxq->mana_rx_debugfs, rxq->gdma_rq, &mana_dbg_q_fops);
+	debugfs_create_file("cq_dump", 0400, rxq->mana_rx_debugfs, rxq->rx_cq.gdma_cq,
+			    &mana_dbg_q_fops);
+}
+
 static int mana_add_rx_queues(struct mana_port_context *apc,
 			      struct net_device *ndev)
 {
@@ -2326,6 +2421,8 @@ static int mana_add_rx_queues(struct mana_port_context *apc,
 		u64_stats_init(&rxq->stats.syncp);
 
 		apc->rxqs[i] = rxq;
+
+		mana_create_rxq_debugfs(apc, i);
 	}
 
 	apc->default_rxobj = apc->rxqs[0]->rxobj;
@@ -2518,14 +2615,19 @@ void mana_query_gf_stats(struct mana_port_context *apc)
 static int mana_init_port(struct net_device *ndev)
 {
 	struct mana_port_context *apc = netdev_priv(ndev);
+	struct gdma_dev *gd = apc->ac->gdma_dev;
 	u32 max_txq, max_rxq, max_queues;
 	int port_idx = apc->port_idx;
+	struct gdma_context *gc;
+	char vport[32];
 	int err;
 
 	err = mana_init_port_context(apc);
 	if (err)
 		return err;
 
+	gc = gd->gdma_context;
+
 	err = mana_query_vport_cfg(apc, port_idx, &max_txq, &max_rxq,
 				   &apc->indir_table_sz);
 	if (err) {
@@ -2542,7 +2644,8 @@ static int mana_init_port(struct net_device *ndev)
 		apc->num_queues = apc->max_queues;
 
 	eth_hw_addr_set(ndev, apc->mac_addr);
-
+	sprintf(vport, "vport%d", port_idx);
+	apc->mana_port_debugfs = debugfs_create_dir(vport, gc->mana_pci_debugfs);
 	return 0;
 
 reset_apc:

include/net/mana/gdma.h

@@ -267,7 +267,8 @@ struct gdma_event {
 struct gdma_queue;
 
 struct mana_eq {
-	struct gdma_queue *eq;
+	struct gdma_queue	*eq;
+	struct dentry		*mana_eq_debugfs;
 };
 
 typedef void gdma_eq_callback(void *context, struct gdma_queue *q,
@@ -365,6 +366,7 @@ struct gdma_irq_context {
 
 struct gdma_context {
 	struct device		*dev;
+	struct dentry		*mana_pci_debugfs;
 
 	/* Per-vPort max number of queues */
 	unsigned int		max_num_queues;
@@ -878,5 +880,7 @@ int mana_gd_send_request(struct gdma_context *gc, u32 req_len, const void *req,
 			 u32 resp_len, void *resp);
 
 int mana_gd_destroy_dma_region(struct gdma_context *gc, u64 dma_region_handle);
+void mana_register_debugfs(void);
+void mana_unregister_debugfs(void);
 
 #endif /* _GDMA_H */

include/net/mana/mana.h

@@ -350,6 +350,7 @@ struct mana_rxq {
 	int xdp_rc; /* XDP redirect return code */
 
 	struct page_pool *page_pool;
+	struct dentry *mana_rx_debugfs;
 
 	/* MUST BE THE LAST MEMBER:
 	 * Each receive buffer has an associated mana_recv_buf_oob.
@@ -363,6 +364,8 @@ struct mana_tx_qp {
 	struct mana_cq tx_cq;
 
 	mana_handle_t tx_object;
+
+	struct dentry *mana_tx_debugfs;
 };
 
 struct mana_ethtool_stats {
@@ -407,6 +410,7 @@ struct mana_context {
 	u16 num_ports;
 
 	struct mana_eq *eqs;
+	struct dentry *mana_eqs_debugfs;
 
 	struct net_device *ports[MAX_PORTS_IN_MANA_DEV];
 };
@@ -468,6 +472,9 @@ struct mana_port_context {
 	bool port_st_save; /* Saved port state */
 
 	struct mana_ethtool_stats eth_stats;
+
+	/* Debugfs */
+	struct dentry *mana_port_debugfs;
 };
 
 netdev_tx_t mana_start_xmit(struct sk_buff *skb, struct net_device *ndev);
@@ -494,6 +501,7 @@ int mana_pre_alloc_rxbufs(struct mana_port_context *apc, int mtu, int num_queues
 void mana_pre_dealloc_rxbufs(struct mana_port_context *apc);
 
 extern const struct ethtool_ops mana_ethtool_ops;
+extern struct dentry *mana_debugfs_root;
 
 /* A CQ can be created not associated with any EQ */
 #define GDMA_CQ_NO_EQ  0xffff