aboutsummaryrefslogtreecommitdiff
path: root/drivers/net/wireless/ath/main.c
diff options
context:
space:
mode:
authorLuis R. Rodriguez <lrodriguez@atheros.com>2009-08-12 09:56:59 -0700
committerJohn W. Linville <linville@tuxdriver.com>2009-08-14 09:14:05 -0400
commitd15dd3e5d74186a3b0a4db271b440bbdc0f6da36 (patch)
tree782cad60e7caa4330f23ef141cc2aec25663097e /drivers/net/wireless/ath/main.c
parent5ef5da0ff2fc4f04c856f4ce9a757e318a02ad06 (diff)
ath: add common ath_rxbuf_alloc() and make ath9k use it
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>
Diffstat (limited to 'drivers/net/wireless/ath/main.c')
-rw-r--r--drivers/net/wireless/ath/main.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/net/wireless/ath/main.c b/drivers/net/wireless/ath/main.c
index 9949b11cb15..487193f1de1 100644
--- a/drivers/net/wireless/ath/main.c
+++ b/drivers/net/wireless/ath/main.c
@@ -17,6 +17,42 @@
#include <linux/kernel.h>
#include <linux/module.h>
+#include "ath.h"
+
MODULE_AUTHOR("Atheros Communications");
MODULE_DESCRIPTION("Shared library for Atheros wireless LAN cards.");
MODULE_LICENSE("Dual BSD/GPL");
+
+struct sk_buff *ath_rxbuf_alloc(struct ath_common *common,
+ u32 len,
+ gfp_t gfp_mask)
+{
+ struct sk_buff *skb;
+ u32 off;
+
+ /*
+ * Cache-line-align. This is important (for the
+ * 5210 at least) as not doing so causes bogus data
+ * in rx'd frames.
+ */
+
+ /* Note: the kernel can allocate a value greater than
+ * what we ask it to give us. We really only need 4 KB as that
+ * is this hardware supports and in fact we need at least 3849
+ * as that is the MAX AMSDU size this hardware supports.
+ * Unfortunately this means we may get 8 KB here from the
+ * kernel... and that is actually what is observed on some
+ * systems :( */
+ skb = __dev_alloc_skb(len + common->cachelsz - 1, gfp_mask);
+ if (skb != NULL) {
+ off = ((unsigned long) skb->data) % common->cachelsz;
+ if (off != 0)
+ skb_reserve(skb, common->cachelsz - off);
+ } else {
+ printk(KERN_ERR "skbuff alloc of size %u failed\n", len);
+ return NULL;
+ }
+
+ return skb;
+}
+EXPORT_SYMBOL(ath_rxbuf_alloc);