LXR linux/drivers/net/wireless/ath/main.c

   1/*
   2 * Copyright (c) 2009 Atheros Communications Inc.
   3 *
   4 * Permission to use, copy, modify, and/or distribute this software for any
   5 * purpose with or without fee is hereby granted, provided that the above
   6 * copyright notice and this permission notice appear in all copies.
   7 *
   8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19
  20#include "ath.h"
  21
  22MODULE_AUTHOR("Atheros Communications");
  23MODULE_DESCRIPTION("Shared library for Atheros wireless LAN cards.");
  24MODULE_LICENSE("Dual BSD/GPL");
  25
  26struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
  27                                u32 len,
  28                                gfp_t gfp_mask)
  29{
  30        struct sk_buff *skb;
  31        u32 off;
  32
  33        /*
  34         * Cache-line-align.  This is important (for the
  35         * 5210 at least) as not doing so causes bogus data
  36         * in rx'd frames.
  37         */
  38
  39        /* Note: the kernel can allocate a value greater than
  40         * what we ask it to give us. We really only need 4 KB as that
  41         * is this hardware supports and in fact we need at least 3849
  42         * as that is the MAX AMSDU size this hardware supports.
  43         * Unfortunately this means we may get 8 KB here from the
  44         * kernel... and that is actually what is observed on some
  45         * systems :( */
  46        skb = __dev_alloc_skb(len + common->cachelsz - 1, gfp_mask);
  47        if (skb != NULL) {
  48                off = ((unsigned long) skb->data) % common->cachelsz;
  49                if (off != 0)
  50                        skb_reserve(skb, common->cachelsz - off);
  51        } else {
  52                printk(KERN_ERR "skbuff alloc of size %u failed\n", len);
  53                return NULL;
  54        }
  55
  56        return skb;
  57}
  58EXPORT_SYMBOL(ath_rxbuf_alloc);
  59