1 files changed, 116 insertions, 0 deletions
diff --git a/drivers/net/wwan/t7xx/t7xx_port_trace.c b/drivers/net/wwan/t7xx/t7xx_port_trace.c
new file mode 100644
index 000000000..6a3f36385
--- /dev/null
+++ b/drivers/net/wwan/t7xx/t7xx_port_trace.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2022 Intel Corporation.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/relay.h>
+#include <linux/skbuff.h>
+#include <linux/wwan.h>
+
+#include "t7xx_port.h"
+#include "t7xx_port_proxy.h"
+#include "t7xx_state_monitor.h"
+
+#define T7XX_TRC_SUB_BUFF_SIZE		131072
+#define T7XX_TRC_N_SUB_BUFF		32
+
+static struct dentry *t7xx_trace_create_buf_file_handler(const char *filename,
+							 struct dentry *parent,
+							 umode_t mode,
+							 struct rchan_buf *buf,
+							 int *is_global)
+{
+	*is_global = 1;
+	return debugfs_create_file(filename, mode, parent, buf,
+				   &relay_file_operations);
+}
+
+static int t7xx_trace_remove_buf_file_handler(struct dentry *dentry)
+{
+	debugfs_remove(dentry);
+	return 0;
+}
+
+static int t7xx_trace_subbuf_start_handler(struct rchan_buf *buf, void *subbuf,
+					   void *prev_subbuf, size_t prev_padding)
+{
+	if (relay_buf_full(buf)) {
+		pr_err_ratelimited("Relay_buf full dropping traces");
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct rchan_callbacks relay_callbacks = {
+	.subbuf_start = t7xx_trace_subbuf_start_handler,
+	.create_buf_file = t7xx_trace_create_buf_file_handler,
+	.remove_buf_file = t7xx_trace_remove_buf_file_handler,
+};
+
+static void t7xx_trace_port_uninit(struct t7xx_port *port)
+{
+	struct dentry *debugfs_dir = port->t7xx_dev->debugfs_dir;
+	struct rchan *relaych = port->log.relaych;
+
+	if (!relaych)
+		return;
+
+	relay_close(relaych);
+	debugfs_remove_recursive(debugfs_dir);
+}
+
+static int t7xx_trace_port_recv_skb(struct t7xx_port *port, struct sk_buff *skb)
+{
+	struct rchan *relaych = port->log.relaych;
+
+	if (!relaych)
+		return -EINVAL;
+
+	relay_write(relaych, skb->data, skb->len);
+	dev_kfree_skb(skb);
+	return 0;
+}
+
+static void t7xx_port_trace_md_state_notify(struct t7xx_port *port, unsigned int state)
+{
+	struct rchan *relaych = port->log.relaych;
+	struct dentry *debugfs_wwan_dir;
+	struct dentry *debugfs_dir;
+
+	if (state != MD_STATE_READY || relaych)
+		return;
+
+	debugfs_wwan_dir = wwan_get_debugfs_dir(port->dev);
+	if (IS_ERR(debugfs_wwan_dir))
+		return;
+
+	debugfs_dir = debugfs_create_dir(KBUILD_MODNAME, debugfs_wwan_dir);
+	if (IS_ERR_OR_NULL(debugfs_dir)) {
+		wwan_put_debugfs_dir(debugfs_wwan_dir);
+		dev_err(port->dev, "Unable to create debugfs for trace");
+		return;
+	}
+
+	relaych = relay_open("relay_ch", debugfs_dir, T7XX_TRC_SUB_BUFF_SIZE,
+			     T7XX_TRC_N_SUB_BUFF, &relay_callbacks, NULL);
+	if (!relaych)
+		goto err_rm_debugfs_dir;
+
+	wwan_put_debugfs_dir(debugfs_wwan_dir);
+	port->log.relaych = relaych;
+	port->t7xx_dev->debugfs_dir = debugfs_dir;
+	return;
+
+err_rm_debugfs_dir:
+	debugfs_remove_recursive(debugfs_dir);
+	wwan_put_debugfs_dir(debugfs_wwan_dir);
+	dev_err(port->dev, "Unable to create trace port %s", port->port_conf->name);
+}
+
+struct port_ops t7xx_trace_port_ops = {
+	.recv_skb = t7xx_trace_port_recv_skb,
+	.uninit = t7xx_trace_port_uninit,
+	.md_state_notify = t7xx_port_trace_md_state_notify,
+};