bnxt_en: add debugfs support for DIM

This adds debugfs support for bnxt_en with the purpose of allowing users
to examine the current DIM profile in use for each receive queue.  This
was instrumental in debugging issues found with DIM and ensuring that
the profiles we expect to use are the profiles being used.

Signed-off-by: Andy Gospodarek <gospo@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 124 insertions, 0 deletions

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_debugfs.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_debugfs.c
new file mode 100644
index 000000000000..94e208e9789f
--- /dev/null
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_debugfs.c
@@ -0,0 +1,124 @@
+/* Broadcom NetXtreme-C/E network driver.
+ *
+ * Copyright (c) 2017-2018 Broadcom Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include "bnxt_hsi.h"
+#include <linux/net_dim.h>
+#include "bnxt.h"
+#include "bnxt_debugfs.h"
+
+static struct dentry *bnxt_debug_mnt;
+
+static ssize_t debugfs_dim_read(struct file *filep,
+				char __user *buffer,
+				size_t count, loff_t *ppos)
+{
+	struct net_dim *dim = filep->private_data;
+	int len;
+	char *buf;
+
+	if (*ppos)
+		return 0;
+	if (!dim)
+		return -ENODEV;
+	buf = kasprintf(GFP_KERNEL,
+			"state = %d\n" \
+			"profile_ix = %d\n" \
+			"mode = %d\n" \
+			"tune_state = %d\n" \
+			"steps_right = %d\n" \
+			"steps_left = %d\n" \
+			"tired = %d\n",
+			dim->state,
+			dim->profile_ix,
+			dim->mode,
+			dim->tune_state,
+			dim->steps_right,
+			dim->steps_left,
+			dim->tired);
+	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_dim_fops = {
+	.owner = THIS_MODULE,
+	.open = simple_open,
+	.read = debugfs_dim_read,
+};
+
+static struct dentry *debugfs_dim_ring_init(struct net_dim *dim, int ring_idx,
+					    struct dentry *dd)
+{
+	static char qname[16];
+
+	snprintf(qname, 10, "%d", ring_idx);
+	return debugfs_create_file(qname, 0600, dd,
+				   dim, &debugfs_dim_fops);
+}
+
+void bnxt_debug_dev_init(struct bnxt *bp)
+{
+	const char *pname = pci_name(bp->pdev);
+	struct dentry *pdevf;
+	int i;
+
+	bp->debugfs_pdev = debugfs_create_dir(pname, bnxt_debug_mnt);
+	if (bp->debugfs_pdev) {
+		pdevf = debugfs_create_dir("dim", bp->debugfs_pdev);
+		if (!pdevf) {
+			pr_err("failed to create debugfs entry %s/dim\n",
+			       pname);
+			return;
+		}
+		bp->debugfs_dim = pdevf;
+		/* create files for each rx ring */
+		for (i = 0; i < bp->cp_nr_rings; i++) {
+			struct bnxt_cp_ring_info *cpr = &bp->bnapi[i]->cp_ring;
+
+			if (cpr && bp->bnapi[i]->rx_ring) {
+				pdevf = debugfs_dim_ring_init(&cpr->dim, i,
+							      bp->debugfs_dim);
+				if (!pdevf)
+					pr_err("failed to create debugfs entry %s/dim/%d\n",
+					       pname, i);
+			}
+		}
+	} else {
+		pr_err("failed to create debugfs entry %s\n", pname);
+	}
+}
+
+void bnxt_debug_dev_exit(struct bnxt *bp)
+{
+	if (bp) {
+		debugfs_remove_recursive(bp->debugfs_pdev);
+		bp->debugfs_pdev = NULL;
+	}
+}
+
+void bnxt_debug_init(void)
+{
+	bnxt_debug_mnt = debugfs_create_dir("bnxt_en", NULL);
+	if (!bnxt_debug_mnt)
+		pr_err("failed to init bnxt_en debugfs\n");
+}
+
+void bnxt_debug_exit(void)
+{
+	debugfs_remove_recursive(bnxt_debug_mnt);
+}