// 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)
{
        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);
        port->log.relaych = NULL;
}

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,
};