root/drivers/dma-buf/sync_debug.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Sync File validation framework and debug information
 *
 * Copyright (C) 2012 Google, Inc.
 */

#include <linux/debugfs.h>
#include "sync_debug.h"

static struct dentry *dbgfs;

static LIST_HEAD(sync_timeline_list_head);
static DEFINE_SPINLOCK(sync_timeline_list_lock);

void sync_timeline_debug_add(struct sync_timeline *obj)
{
        unsigned long flags;

        spin_lock_irqsave(&sync_timeline_list_lock, flags);
        list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
        spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
}

void sync_timeline_debug_remove(struct sync_timeline *obj)
{
        unsigned long flags;

        spin_lock_irqsave(&sync_timeline_list_lock, flags);
        list_del(&obj->sync_timeline_list);
        spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
}

static const char *sync_status_str(int status)
{
        if (status < 0)
                return "error";

        if (status > 0)
                return "signaled";

        return "active";
}

static void sync_print_fence(struct seq_file *s,
                             struct dma_fence *fence, bool show)
{
        struct sync_timeline *parent = dma_fence_parent(fence);
        int status;

        status = dma_fence_get_status_locked(fence);

        seq_printf(s, "  %s%sfence %s",
                   show ? parent->name : "",
                   show ? "_" : "",
                   sync_status_str(status));

        if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags)) {
                struct timespec64 ts64 =
                        ktime_to_timespec64(fence->timestamp);

                seq_printf(s, "@%ptSp", &ts64);
        }

        seq_printf(s, ": %lld", fence->seqno);
        seq_printf(s, " / %d", parent->value);
        seq_putc(s, '\n');
}

static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
{
        struct list_head *pos;

        seq_printf(s, "%s: %d\n", obj->name, obj->value);

        spin_lock(&obj->lock); /* Caller already disabled IRQ. */
        list_for_each(pos, &obj->pt_list) {
                struct sync_pt *pt = container_of(pos, struct sync_pt, link);
                sync_print_fence(s, &pt->base, false);
        }
        spin_unlock(&obj->lock);
}

static int sync_info_debugfs_show(struct seq_file *s, void *unused)
{
        struct list_head *pos;

        seq_puts(s, "objs:\n--------------\n");

        spin_lock_irq(&sync_timeline_list_lock);
        list_for_each(pos, &sync_timeline_list_head) {
                struct sync_timeline *obj =
                        container_of(pos, struct sync_timeline,
                                     sync_timeline_list);

                sync_print_obj(s, obj);
                seq_putc(s, '\n');
        }
        spin_unlock_irq(&sync_timeline_list_lock);

        seq_puts(s, "fences:\n--------------\n");

        return 0;
}

DEFINE_SHOW_ATTRIBUTE(sync_info_debugfs);

static __init int sync_debugfs_init(void)
{
        dbgfs = debugfs_create_dir("sync", NULL);

        /*
         * The debugfs files won't ever get removed and thus, there is
         * no need to protect it against removal races. The use of
         * debugfs_create_file_unsafe() is actually safe here.
         */
        debugfs_create_file_unsafe("info", 0444, dbgfs, NULL,
                                   &sync_info_debugfs_fops);
        debugfs_create_file_unsafe("sw_sync", 0644, dbgfs, NULL,
                                   &sw_sync_debugfs_fops);

        return 0;
}
late_initcall(sync_debugfs_init);