/* SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause) */
/*
 * Copyright (c) 2017 Hisilicon Limited.
 * Copyright (c) 2007, 2008 Mellanox Technologies. All rights reserved.
 */

#include <rdma/ib_umem.h>
#include "hns_roce_device.h"

int hns_roce_db_map_user(struct hns_roce_ucontext *context, unsigned long virt,
                         struct hns_roce_db *db)
{
        unsigned long page_addr = virt & PAGE_MASK;
        struct hns_roce_user_db_page *page;
        unsigned int offset;
        int ret = 0;

        mutex_lock(&context->page_mutex);

        list_for_each_entry(page, &context->page_list, list)
                if (page->user_virt == page_addr)
                        goto found;

        page = kmalloc_obj(*page);
        if (!page) {
                ret = -ENOMEM;
                goto out;
        }

        refcount_set(&page->refcount, 1);
        page->user_virt = page_addr;
        page->umem = ib_umem_get(context->ibucontext.device, page_addr,
                                 PAGE_SIZE, 0);
        if (IS_ERR(page->umem)) {
                ret = PTR_ERR(page->umem);
                kfree(page);
                goto out;
        }

        list_add(&page->list, &context->page_list);

found:
        offset = virt - page_addr;
        db->dma = sg_dma_address(page->umem->sgt_append.sgt.sgl) + offset;
        db->virt_addr = sg_virt(page->umem->sgt_append.sgt.sgl) + offset;
        db->u.user_page = page;
        refcount_inc(&page->refcount);

out:
        mutex_unlock(&context->page_mutex);

        return ret;
}

void hns_roce_db_unmap_user(struct hns_roce_ucontext *context,
                            struct hns_roce_db *db)
{
        mutex_lock(&context->page_mutex);

        refcount_dec(&db->u.user_page->refcount);
        if (refcount_dec_if_one(&db->u.user_page->refcount)) {
                list_del(&db->u.user_page->list);
                ib_umem_release(db->u.user_page->umem);
                kfree(db->u.user_page);
        }

        mutex_unlock(&context->page_mutex);
}

static struct hns_roce_db_pgdir *hns_roce_alloc_db_pgdir(
                                        struct device *dma_device)
{
        struct hns_roce_db_pgdir *pgdir;

        pgdir = kzalloc_obj(*pgdir);
        if (!pgdir)
                return NULL;

        bitmap_fill(pgdir->order1,
                    HNS_ROCE_DB_PER_PAGE / HNS_ROCE_DB_TYPE_COUNT);
        pgdir->bits[0] = pgdir->order0;
        pgdir->bits[1] = pgdir->order1;
        pgdir->page = dma_alloc_coherent(dma_device, PAGE_SIZE,
                                         &pgdir->db_dma, GFP_KERNEL);
        if (!pgdir->page) {
                kfree(pgdir);
                return NULL;
        }

        return pgdir;
}

static int hns_roce_alloc_db_from_pgdir(struct hns_roce_db_pgdir *pgdir,
                                        struct hns_roce_db *db, int order)
{
        unsigned long o;
        unsigned long i;

        for (o = order; o <= 1; ++o) {
                i = find_first_bit(pgdir->bits[o], HNS_ROCE_DB_PER_PAGE >> o);
                if (i < HNS_ROCE_DB_PER_PAGE >> o)
                        goto found;
        }

        return -ENOMEM;

found:
        clear_bit(i, pgdir->bits[o]);

        i <<= o;

        if (o > order)
                set_bit(i ^ 1, pgdir->bits[order]);

        db->u.pgdir     = pgdir;
        db->index       = i;
        db->db_record   = pgdir->page + db->index;
        db->dma         = pgdir->db_dma  + db->index * HNS_ROCE_DB_UNIT_SIZE;
        db->order       = order;

        return 0;
}

int hns_roce_alloc_db(struct hns_roce_dev *hr_dev, struct hns_roce_db *db,
                      int order)
{
        struct hns_roce_db_pgdir *pgdir;
        int ret = 0;

        mutex_lock(&hr_dev->pgdir_mutex);

        list_for_each_entry(pgdir, &hr_dev->pgdir_list, list)
                if (!hns_roce_alloc_db_from_pgdir(pgdir, db, order))
                        goto out;

        pgdir = hns_roce_alloc_db_pgdir(hr_dev->dev);
        if (!pgdir) {
                ret = -ENOMEM;
                goto out;
        }

        list_add(&pgdir->list, &hr_dev->pgdir_list);

        /* This should never fail -- we just allocated an empty page: */
        WARN_ON(hns_roce_alloc_db_from_pgdir(pgdir, db, order));

out:
        mutex_unlock(&hr_dev->pgdir_mutex);

        return ret;
}

void hns_roce_free_db(struct hns_roce_dev *hr_dev, struct hns_roce_db *db)
{
        unsigned long o;
        unsigned long i;

        mutex_lock(&hr_dev->pgdir_mutex);

        o = db->order;
        i = db->index;

        if (db->order == 0 && test_bit(i ^ 1, db->u.pgdir->order0)) {
                clear_bit(i ^ 1, db->u.pgdir->order0);
                ++o;
        }

        i >>= o;
        set_bit(i, db->u.pgdir->bits[o]);

        if (bitmap_full(db->u.pgdir->order1,
                        HNS_ROCE_DB_PER_PAGE / HNS_ROCE_DB_TYPE_COUNT)) {
                dma_free_coherent(hr_dev->dev, PAGE_SIZE, db->u.pgdir->page,
                                  db->u.pgdir->db_dma);
                list_del(&db->u.pgdir->list);
                kfree(db->u.pgdir);
        }

        mutex_unlock(&hr_dev->pgdir_mutex);
}