/*
 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     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.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/bitmap.h>

#include "mthca_dev.h"

/* Trivial bitmap-based allocator */
u32 mthca_alloc(struct mthca_alloc *alloc)
{
        unsigned long flags;
        u32 obj;

        spin_lock_irqsave(&alloc->lock, flags);

        obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last);
        if (obj >= alloc->max) {
                alloc->top = (alloc->top + alloc->max) & alloc->mask;
                obj = find_first_zero_bit(alloc->table, alloc->max);
        }

        if (obj < alloc->max) {
                __set_bit(obj, alloc->table);
                obj |= alloc->top;
        } else
                obj = -1;

        spin_unlock_irqrestore(&alloc->lock, flags);

        return obj;
}

void mthca_free(struct mthca_alloc *alloc, u32 obj)
{
        unsigned long flags;

        obj &= alloc->max - 1;

        spin_lock_irqsave(&alloc->lock, flags);

        __clear_bit(obj, alloc->table);
        alloc->last = min(alloc->last, obj);
        alloc->top = (alloc->top + alloc->max) & alloc->mask;

        spin_unlock_irqrestore(&alloc->lock, flags);
}

int mthca_alloc_init(struct mthca_alloc *alloc, u32 num, u32 mask,
                     u32 reserved)
{
        /* num must be a power of 2 */
        if (num != 1 << (ffs(num) - 1))
                return -EINVAL;

        alloc->last = 0;
        alloc->top  = 0;
        alloc->max  = num;
        alloc->mask = mask;
        spin_lock_init(&alloc->lock);
        alloc->table = bitmap_zalloc(num, GFP_KERNEL);
        if (!alloc->table)
                return -ENOMEM;

        bitmap_set(alloc->table, 0, reserved);

        return 0;
}

void mthca_alloc_cleanup(struct mthca_alloc *alloc)
{
        bitmap_free(alloc->table);
}

/*
 * Array of pointers with lazy allocation of leaf pages.  Callers of
 * _get, _set and _clear methods must use a lock or otherwise
 * serialize access to the array.
 */

#define MTHCA_ARRAY_MASK (PAGE_SIZE / sizeof (void *) - 1)

void *mthca_array_get(struct mthca_array *array, int index)
{
        int p = (index * sizeof (void *)) >> PAGE_SHIFT;

        if (array->page_list[p].page)
                return array->page_list[p].page[index & MTHCA_ARRAY_MASK];
        else
                return NULL;
}

int mthca_array_set(struct mthca_array *array, int index, void *value)
{
        int p = (index * sizeof (void *)) >> PAGE_SHIFT;

        /* Allocate with GFP_ATOMIC because we'll be called with locks held. */
        if (!array->page_list[p].page)
                array->page_list[p].page = (void **) get_zeroed_page(GFP_ATOMIC);

        if (!array->page_list[p].page)
                return -ENOMEM;

        array->page_list[p].page[index & MTHCA_ARRAY_MASK] = value;
        ++array->page_list[p].used;

        return 0;
}

void mthca_array_clear(struct mthca_array *array, int index)
{
        int p = (index * sizeof (void *)) >> PAGE_SHIFT;

        if (--array->page_list[p].used == 0) {
                free_page((unsigned long) array->page_list[p].page);
                array->page_list[p].page = NULL;
        } else
                array->page_list[p].page[index & MTHCA_ARRAY_MASK] = NULL;

        if (array->page_list[p].used < 0)
                pr_debug("Array %p index %d page %d with ref count %d < 0\n",
                         array, index, p, array->page_list[p].used);
}

int mthca_array_init(struct mthca_array *array, int nent)
{
        int npage = (nent * sizeof (void *) + PAGE_SIZE - 1) / PAGE_SIZE;
        int i;

        array->page_list = kmalloc_objs(*array->page_list, npage);
        if (!array->page_list)
                return -ENOMEM;

        for (i = 0; i < npage; ++i) {
                array->page_list[i].page = NULL;
                array->page_list[i].used = 0;
        }

        return 0;
}

void mthca_array_cleanup(struct mthca_array *array, int nent)
{
        int i;

        for (i = 0; i < (nent * sizeof (void *) + PAGE_SIZE - 1) / PAGE_SIZE; ++i)
                free_page((unsigned long) array->page_list[i].page);

        kfree(array->page_list);
}

/*
 * Handling for queue buffers -- we allocate a bunch of memory and
 * register it in a memory region at HCA virtual address 0.  If the
 * requested size is > max_direct, we split the allocation into
 * multiple pages, so we don't require too much contiguous memory.
 */

int mthca_buf_alloc(struct mthca_dev *dev, int size, int max_direct,
                    union mthca_buf *buf, int *is_direct, struct mthca_pd *pd,
                    int hca_write, struct mthca_mr *mr)
{
        int err = -ENOMEM;
        int npages, shift;
        u64 *dma_list = NULL;
        dma_addr_t t;
        int i;

        if (size <= max_direct) {
                *is_direct = 1;
                npages     = 1;
                shift      = get_order(size) + PAGE_SHIFT;

                buf->direct.buf = dma_alloc_coherent(&dev->pdev->dev,
                                                     size, &t, GFP_KERNEL);
                if (!buf->direct.buf)
                        return -ENOMEM;

                dma_unmap_addr_set(&buf->direct, mapping, t);

                while (t & ((1 << shift) - 1)) {
                        --shift;
                        npages *= 2;
                }

                dma_list = kmalloc_array(npages, sizeof(*dma_list),
                                         GFP_KERNEL);
                if (!dma_list)
                        goto err_free;

                for (i = 0; i < npages; ++i)
                        dma_list[i] = t + i * (1 << shift);
        } else {
                *is_direct = 0;
                npages     = (size + PAGE_SIZE - 1) / PAGE_SIZE;
                shift      = PAGE_SHIFT;

                dma_list = kmalloc_array(npages, sizeof(*dma_list),
                                         GFP_KERNEL);
                if (!dma_list)
                        return -ENOMEM;

                buf->page_list = kmalloc_objs(*buf->page_list, npages);
                if (!buf->page_list)
                        goto err_out;

                for (i = 0; i < npages; ++i)
                        buf->page_list[i].buf = NULL;

                for (i = 0; i < npages; ++i) {
                        buf->page_list[i].buf =
                                dma_alloc_coherent(&dev->pdev->dev, PAGE_SIZE,
                                                   &t, GFP_KERNEL);
                        if (!buf->page_list[i].buf)
                                goto err_free;

                        dma_list[i] = t;
                        dma_unmap_addr_set(&buf->page_list[i], mapping, t);

                        clear_page(buf->page_list[i].buf);
                }
        }

        err = mthca_mr_alloc_phys(dev, pd->pd_num,
                                  dma_list, shift, npages,
                                  0, size,
                                  MTHCA_MPT_FLAG_LOCAL_READ |
                                  (hca_write ? MTHCA_MPT_FLAG_LOCAL_WRITE : 0),
                                  mr);
        if (err)
                goto err_free;

        kfree(dma_list);

        return 0;

err_free:
        mthca_buf_free(dev, size, buf, *is_direct, NULL);

err_out:
        kfree(dma_list);

        return err;
}

void mthca_buf_free(struct mthca_dev *dev, int size, union mthca_buf *buf,
                    int is_direct, struct mthca_mr *mr)
{
        int i;

        if (mr)
                mthca_free_mr(dev, mr);

        if (is_direct)
                dma_free_coherent(&dev->pdev->dev, size, buf->direct.buf,
                                  dma_unmap_addr(&buf->direct, mapping));
        else {
                for (i = 0; i < (size + PAGE_SIZE - 1) / PAGE_SIZE; ++i)
                        dma_free_coherent(&dev->pdev->dev, PAGE_SIZE,
                                          buf->page_list[i].buf,
                                          dma_unmap_addr(&buf->page_list[i],
                                                         mapping));
                kfree(buf->page_list);
        }
}