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c2_alloc.c

/*
 * Copyright (c) 2004 Topspin Communications.  All rights reserved.
 * Copyright (c) 2005 Open Grid Computing, Inc. 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 "c2.h"

static int c2_alloc_mqsp_chunk(struct c2_dev *c2dev, gfp_t gfp_mask,
                         struct sp_chunk **head)
{
      int i;
      struct sp_chunk *new_head;
      dma_addr_t dma_addr;

      new_head = dma_alloc_coherent(&c2dev->pcidev->dev, PAGE_SIZE,
                              &dma_addr, gfp_mask);
      if (new_head == NULL)
            return -ENOMEM;

      new_head->dma_addr = dma_addr;
      pci_unmap_addr_set(new_head, mapping, new_head->dma_addr);

      new_head->next = NULL;
      new_head->head = 0;

      /* build list where each index is the next free slot */
      for (i = 0;
           i < (PAGE_SIZE - sizeof(struct sp_chunk) -
              sizeof(u16)) / sizeof(u16) - 1;
           i++) {
            new_head->shared_ptr[i] = i + 1;
      }
      /* terminate list */
      new_head->shared_ptr[i] = 0xFFFF;

      *head = new_head;
      return 0;
}

int c2_init_mqsp_pool(struct c2_dev *c2dev, gfp_t gfp_mask,
                  struct sp_chunk **root)
{
      return c2_alloc_mqsp_chunk(c2dev, gfp_mask, root);
}

void c2_free_mqsp_pool(struct c2_dev *c2dev, struct sp_chunk *root)
{
      struct sp_chunk *next;

      while (root) {
            next = root->next;
            dma_free_coherent(&c2dev->pcidev->dev, PAGE_SIZE, root,
                          pci_unmap_addr(root, mapping));
            root = next;
      }
}

u16 *c2_alloc_mqsp(struct c2_dev *c2dev, struct sp_chunk *head,
               dma_addr_t *dma_addr, gfp_t gfp_mask)
{
      u16 mqsp;

      while (head) {
            mqsp = head->head;
            if (mqsp != 0xFFFF) {
                  head->head = head->shared_ptr[mqsp];
                  break;
            } else if (head->next == NULL) {
                  if (c2_alloc_mqsp_chunk(c2dev, gfp_mask, &head->next) ==
                      0) {
                        head = head->next;
                        mqsp = head->head;
                        head->head = head->shared_ptr[mqsp];
                        break;
                  } else
                        return NULL;
            } else
                  head = head->next;
      }
      if (head) {
            *dma_addr = head->dma_addr +
                      ((unsigned long) &(head->shared_ptr[mqsp]) -
                       (unsigned long) head);
            pr_debug("%s addr %p dma_addr %llx\n", __FUNCTION__,
                   &(head->shared_ptr[mqsp]), (unsigned long long) *dma_addr);
            return &(head->shared_ptr[mqsp]);
      }
      return NULL;
}

void c2_free_mqsp(u16 * mqsp)
{
      struct sp_chunk *head;
      u16 idx;

      /* The chunk containing this ptr begins at the page boundary */
      head = (struct sp_chunk *) ((unsigned long) mqsp & PAGE_MASK);

      /* Link head to new mqsp */
      *mqsp = head->head;

      /* Compute the shared_ptr index */
      idx = ((unsigned long) mqsp & ~PAGE_MASK) >> 1;
      idx -= (unsigned long) &(((struct sp_chunk *) 0)->shared_ptr[0]) >> 1;

      /* Point this index at the head */
      head->shared_ptr[idx] = head->head;

      /* Point head at this index */
      head->head = idx;
}

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