d15dd3e5d7
Turns out ath5k and ath9k can share the same helper to allocates RX skbs. We allocate skbs aligned to the cache line size. This requirement seems to have come from AR5210; when this was not done it seems sometimes we'd get bogus data. I'm also told it may have been a performance enhancement consideration. In the end I can't be sure we can remove this on new hardware so just keep this and start sharing it through ath.ko. Make ath9k start using this, ath5k is next. Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
59 lines
1.9 KiB
C
59 lines
1.9 KiB
C
/*
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* Copyright (c) 2009 Atheros Communications Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include "ath.h"
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MODULE_AUTHOR("Atheros Communications");
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MODULE_DESCRIPTION("Shared library for Atheros wireless LAN cards.");
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MODULE_LICENSE("Dual BSD/GPL");
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struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
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u32 len,
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gfp_t gfp_mask)
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{
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struct sk_buff *skb;
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u32 off;
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/*
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* Cache-line-align. This is important (for the
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* 5210 at least) as not doing so causes bogus data
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* in rx'd frames.
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*/
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/* Note: the kernel can allocate a value greater than
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* what we ask it to give us. We really only need 4 KB as that
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* is this hardware supports and in fact we need at least 3849
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* as that is the MAX AMSDU size this hardware supports.
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* Unfortunately this means we may get 8 KB here from the
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* kernel... and that is actually what is observed on some
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* systems :( */
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skb = __dev_alloc_skb(len + common->cachelsz - 1, gfp_mask);
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if (skb != NULL) {
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off = ((unsigned long) skb->data) % common->cachelsz;
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if (off != 0)
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skb_reserve(skb, common->cachelsz - off);
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} else {
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printk(KERN_ERR "skbuff alloc of size %u failed\n", len);
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return NULL;
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}
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return skb;
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}
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EXPORT_SYMBOL(ath_rxbuf_alloc);
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