/*
 *  IBM eServer eHCA Infiniband device driver for Linux on POWER
 *
 *  internal queue handling
 *
 *  Authors: Waleri Fomin <fomin@de.ibm.com>
 *           Reinhard Ernst <rernst@de.ibm.com>
 *           Christoph Raisch <raisch@de.ibm.com>
 *
 *  Copyright (c) 2005 IBM Corporation
 *
 *  This source code is distributed under a dual license of GPL v2.0 and OpenIB
 *  BSD.
 *
 * OpenIB BSD License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials
 * provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "ehca_tools.h"
#include "ipz_pt_fn.h"
#include "ehca_classes.h"

#define PAGES_PER_KPAGE (PAGE_SIZE >> EHCA_PAGESHIFT)

struct kmem_cache *small_qp_cache;

void *ipz_qpageit_get_inc(struct ipz_queue *queue)
{
        void *ret = ipz_qeit_get(queue);
        queue->current_q_offset += queue->pagesize;
        if (queue->current_q_offset > queue->queue_length) {
                queue->current_q_offset -= queue->pagesize;
                ret = NULL;
        }
        if (((u64)ret) % queue->pagesize) {
                ehca_gen_err("ERROR!! not at PAGE-Boundary");
                return NULL;
        }
        return ret;
}

void *ipz_qeit_eq_get_inc(struct ipz_queue *queue)
{
        void *ret = ipz_qeit_get(queue);
        u64 last_entry_in_q = queue->queue_length - queue->qe_size;

        queue->current_q_offset += queue->qe_size;
        if (queue->current_q_offset > last_entry_in_q) {
                queue->current_q_offset = 0;
                queue->toggle_state = (~queue->toggle_state) & 1;
        }

        return ret;
}

int ipz_queue_abs_to_offset(struct ipz_queue *queue, u64 addr, u64 *q_offset)
{
        int i;
        for (i = 0; i < queue->queue_length / queue->pagesize; i++) {
                u64 page = (u64)virt_to_abs(queue->queue_pages[i]);
                if (addr >= page && addr < page + queue->pagesize) {
                        *q_offset = addr - page + i * queue->pagesize;
                        return 0;
                }
        }
        return -EINVAL;
}

#if PAGE_SHIFT < EHCA_PAGESHIFT
#error Kernel pages must be at least as large than eHCA pages (4K) !
#endif

/*
 * allocate pages for queue:
 * outer loop allocates whole kernel pages (page aligned) and
 * inner loop divides a kernel page into smaller hca queue pages
 */
static int alloc_queue_pages(struct ipz_queue *queue, const u32 nr_of_pages)
{
        int k, f = 0;
        u8 *kpage;

        while (f < nr_of_pages) {
                kpage = (u8 *)get_zeroed_page(GFP_KERNEL);
                if (!kpage)
                        goto out;

                for (k = 0; k < PAGES_PER_KPAGE && f < nr_of_pages; k++) {
                        queue->queue_pages[f] = (struct ipz_page *)kpage;
                        kpage += EHCA_PAGESIZE;
                        f++;
                }
        }
        return 1;

out:
        for (f = 0; f < nr_of_pages && queue->queue_pages[f];
             f += PAGES_PER_KPAGE)
                free_page((unsigned long)(queue->queue_pages)[f]);
        return 0;
}

static int alloc_small_queue_page(struct ipz_queue *queue, struct ehca_pd *pd)
{
        int order = ilog2(queue->pagesize) - 9;
        struct ipz_small_queue_page *page;
        unsigned long bit;

        mutex_lock(&pd->lock);

        if (!list_empty(&pd->free[order]))
                page = list_entry(pd->free[order].next,
                                  struct ipz_small_queue_page, list);
        else {
                page = kmem_cache_zalloc(small_qp_cache, GFP_KERNEL);
                if (!page)
                        goto out;

                page->page = get_zeroed_page(GFP_KERNEL);
                if (!page->page) {
                        kmem_cache_free(small_qp_cache, page);
                        goto out;
                }

                list_add(&page->list, &pd->free[order]);
        }

        bit = find_first_zero_bit(page->bitmap, IPZ_SPAGE_PER_KPAGE >> order);
        __set_bit(bit, page->bitmap);
        page->fill++;

        if (page->fill == IPZ_SPAGE_PER_KPAGE >> order)
                list_move(&page->list, &pd->full[order]);

        mutex_unlock(&pd->lock);

        queue->queue_pages[0] = (void *)(page->page | (bit << (order + 9)));
        queue->small_page = page;
        queue->offset = bit << (order + 9);
        return 1;

out:
        ehca_err(pd->ib_pd.device, "failed to allocate small queue page");
        return 0;
}

static void free_small_queue_page(struct ipz_queue *queue, struct ehca_pd *pd)
{
        int order = ilog2(queue->pagesize) - 9;
        struct ipz_small_queue_page *page = queue->small_page;
        unsigned long bit;
        int free_page = 0;

        bit = ((unsigned long)queue->queue_pages[0] & ~PAGE_MASK)
                >> (order + 9);

        mutex_lock(&pd->lock);

        __clear_bit(bit, page->bitmap);
        page->fill--;

        if (page->fill == 0) {
                list_del(&page->list);
                free_page = 1;
        }

        if (page->fill == (IPZ_SPAGE_PER_KPAGE >> order) - 1)
                /* the page was full until we freed the chunk */
                list_move_tail(&page->list, &pd->free[order]);

        mutex_unlock(&pd->lock);

        if (free_page) {
                free_page(page->page);
                kmem_cache_free(small_qp_cache, page);
        }
}

int ipz_queue_ctor(struct ehca_pd *pd, struct ipz_queue *queue,
                   const u32 nr_of_pages, const u32 pagesize,
                   const u32 qe_size, const u32 nr_of_sg,
                   int is_small)
{
        if (pagesize > PAGE_SIZE) {
                ehca_gen_err("FATAL ERROR: pagesize=%x "
                             "is greater than kernel page size", pagesize);
                return 0;
        }

        /* init queue fields */
        queue->queue_length = nr_of_pages * pagesize;
        queue->pagesize = pagesize;
        queue->qe_size = qe_size;
        queue->act_nr_of_sg = nr_of_sg;
        queue->current_q_offset = 0;
        queue->toggle_state = 1;
        queue->small_page = NULL;

        /* allocate queue page pointers */
        queue->queue_pages = vmalloc(nr_of_pages * sizeof(void *));
        if (!queue->queue_pages) {
                ehca_gen_err("Couldn't allocate queue page list");
                return 0;
        }
        memset(queue->queue_pages, 0, nr_of_pages * sizeof(void *));

        /* allocate actual queue pages */
        if (is_small) {
                if (!alloc_small_queue_page(queue, pd))
                        goto ipz_queue_ctor_exit0;
        } else
                if (!alloc_queue_pages(queue, nr_of_pages))
                        goto ipz_queue_ctor_exit0;

        return 1;

ipz_queue_ctor_exit0:
        ehca_gen_err("Couldn't alloc pages queue=%p "
                 "nr_of_pages=%x",  queue, nr_of_pages);
        vfree(queue->queue_pages);

        return 0;
}

int ipz_queue_dtor(struct ehca_pd *pd, struct ipz_queue *queue)
{
        int i, nr_pages;

        if (!queue || !queue->queue_pages) {
                ehca_gen_dbg("queue or queue_pages is NULL");
                return 0;
        }

        if (queue->small_page)
                free_small_queue_page(queue, pd);
        else {
                nr_pages = queue->queue_length / queue->pagesize;
                for (i = 0; i < nr_pages; i += PAGES_PER_KPAGE)
                        free_page((unsigned long)queue->queue_pages[i]);
        }

        vfree(queue->queue_pages);

        return 1;
}

int ehca_init_small_qp_cache(void)
{
        small_qp_cache = kmem_cache_create("ehca_cache_small_qp",
                                           sizeof(struct ipz_small_queue_page),
                                           0, SLAB_HWCACHE_ALIGN, NULL);
        if (!small_qp_cache)
                return -ENOMEM;

        return 0;
}

void ehca_cleanup_small_qp_cache(void)
{
        kmem_cache_destroy(small_qp_cache);
}