/*
 * This file is part of the Xilinx DMA IP Core driver for Linux
 *
 * Copyright (c) 2017-2020,  Xilinx, Inc.
 * All rights reserved.
 *
 * This source code is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * The full GNU General Public License is included in this distribution in
 * the file called "COPYING".
 */

#define pr_fmt(fmt)	KBUILD_MODNAME ":%s: " fmt, __func__

#include "thread.h"

#include <linux/kernel.h>

/*
 * kernel thread function wrappers
 */
int qdma_kthread_dump(struct qdma_kthread *thp, char *buf, int buflen,
			int detail)
{
	int len = 0;

	if (!buf || !buflen)
		return 0;

	lock_thread(thp);
	len += sprintf(buf + len, "%s, cpu %u, work %u.\n",
			thp->name, thp->cpu, thp->work_cnt);

	if (detail)
		;

	unlock_thread(thp);

	buf[len] = '\0';
	return len;
}

static inline int xthread_work_pending(struct qdma_kthread *thp)
{
	struct list_head *work_item, *next;

	/* any work items assigned to this thread? */
	if (list_empty(&thp->work_list))
		return 0;


	/* any work item has pending work to do? */
	list_for_each_safe(work_item, next, &thp->work_list) {
		if (thp->fpending && thp->fpending(work_item))
			return 1;

	}
	return 0;
}

static inline void xthread_reschedule(struct qdma_kthread *thp)
{
	if (thp->kth_timeout) {
		pr_debug_thread("%s rescheduling for %u seconds",
				thp->name, thp->kth_timeout);
		qdma_waitq_wait_event_timeout(
				thp->waitq, thp->schedule,
				msecs_to_jiffies(thp->kth_timeout));
	} else {
		pr_debug_thread("%s rescheduling", thp->name);
		qdma_waitq_wait_event(thp->waitq, thp->schedule);
	}
}

static int xthread_main(void *data)
{
	struct qdma_kthread *thp = (struct qdma_kthread *)data;

	pr_debug_thread("%s UP.\n", thp->name);

	disallow_signal(SIGPIPE);

	if (thp->finit)
		thp->finit(thp);


	while (!kthread_should_stop()) {

		struct list_head *work_item, *next;

		pr_debug_thread("%s interruptible\n", thp->name);

		/* any work to do? */
		lock_thread(thp);
		if (!xthread_work_pending(thp)) {
			unlock_thread(thp);
			xthread_reschedule(thp);
			lock_thread(thp);
		}
		thp->schedule = 0;

		if (thp->work_cnt) {
			pr_debug_thread("%s processing %u work items\n",
					thp->name, thp->work_cnt);
			/* do work */
			list_for_each_safe(work_item, next, &thp->work_list) {
				thp->fproc(work_item);
			}
		}
		unlock_thread(thp);
		schedule();
	}

	pr_debug_thread("%s, work done.\n", thp->name);


	if (thp->fdone)
		thp->fdone(thp);

	pr_debug_thread("%s, exit.\n", thp->name);
	return 0;
}

int qdma_kthread_start(struct qdma_kthread *thp, char *name, int id)
{
	int len;

	if (thp->task) {
		pr_warn("kthread %s task already running?\n", thp->name);
		return -EINVAL;
	}

#ifdef __QDMA_VF__
	len = snprintf(thp->name, sizeof(thp->name), "%s_vf_%d", name, id);
	if (len < 0)
		return -EINVAL;
#else
	len = snprintf(thp->name, sizeof(thp->name), "%s%d", name, id);
	if (len < 0)
		return -EINVAL;
#endif
	thp->id = id;

	spin_lock_init(&thp->lock);
	INIT_LIST_HEAD(&thp->work_list);
	qdma_waitq_init(&thp->waitq);

	thp->task = kthread_create_on_node(xthread_main, (void *)thp,
					cpu_to_node(thp->cpu), "%s", thp->name);
	if (IS_ERR(thp->task)) {
		pr_err("kthread %s, create task failed: 0x%lx\n",
			thp->name, (unsigned long)IS_ERR(thp->task));
		thp->task = NULL;
		return -EFAULT;
	}

	kthread_bind(thp->task, thp->cpu);

	pr_debug_thread("kthread 0x%p, %s, cpu %u, task 0x%p.\n",
		thp, thp->name, thp->cpu, thp->task);

	wake_up_process(thp->task);
	return 0;
}

int qdma_kthread_stop(struct qdma_kthread *thp)
{
	int rv;

	if (!thp->task) {
		pr_debug_thread("kthread %s, already stopped.\n", thp->name);
		return 0;
	}

	thp->schedule = 1;
	rv = kthread_stop(thp->task);
	if (rv < 0) {
		pr_warn("kthread %s, stop err %d.\n", thp->name, rv);
		return rv;
	}

	pr_debug_thread("kthread %s, 0x%p, stopped.\n", thp->name, thp->task);
	thp->task = NULL;

	return 0;
}

