ath5k: use rx hw descriptor pointer for self-linked check
Bob Copeland [Wed, 15 Apr 2009 11:57:35 +0000 (07:57 -0400)]
This patch simplifies the code used to detect when the
self-linked DMA buffer is still in use by hardware, by
checking the hardware's rxdp register instead of looking
at the software buffer list.

Signed-off-by: Bob Copeland <me@bobcopeland.com>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/base.c
drivers/net/wireless/ath/ath5k/base.h
drivers/net/wireless/ath/ath5k/dma.c

index 3bde18f..1a6e72f 100644 (file)
@@ -1780,7 +1780,7 @@ ath5k_tasklet_rx(unsigned long data)
        struct sk_buff *skb, *next_skb;
        dma_addr_t next_skb_addr;
        struct ath5k_softc *sc = (void *)data;
-       struct ath5k_buf *bf, *bf_last;
+       struct ath5k_buf *bf;
        struct ath5k_desc *ds;
        int ret;
        int hdrlen;
@@ -1791,7 +1791,6 @@ ath5k_tasklet_rx(unsigned long data)
                ATH5K_WARN(sc, "empty rx buf pool\n");
                goto unlock;
        }
-       bf_last = list_entry(sc->rxbuf.prev, struct ath5k_buf, list);
        do {
                rxs.flag = 0;
 
@@ -1800,24 +1799,9 @@ ath5k_tasklet_rx(unsigned long data)
                skb = bf->skb;
                ds = bf->desc;
 
-               /*
-                * last buffer must not be freed to ensure proper hardware
-                * function. When the hardware finishes also a packet next to
-                * it, we are sure, it doesn't use it anymore and we can go on.
-                */
-               if (bf_last == bf)
-                       bf->flags |= 1;
-               if (bf->flags) {
-                       struct ath5k_buf *bf_next = list_entry(bf->list.next,
-                                       struct ath5k_buf, list);
-                       ret = sc->ah->ah_proc_rx_desc(sc->ah, bf_next->desc,
-                                       &rs);
-                       if (ret)
-                               break;
-                       bf->flags &= ~1;
-                       /* skip the overwritten one (even status is martian) */
-                       goto next;
-               }
+               /* bail if HW is still using self-linked descriptor */
+               if (ath5k_hw_get_rxdp(sc->ah) == bf->daddr)
+                       break;
 
                ret = sc->ah->ah_proc_rx_desc(sc->ah, ds, &rs);
                if (unlikely(ret == -EINPROGRESS))
index 8229561..852b2c1 100644 (file)
@@ -56,7 +56,6 @@
 
 struct ath5k_buf {
        struct list_head        list;
-       unsigned int            flags;  /* rx descriptor flags */
        struct ath5k_desc       *desc;  /* virtual addr of desc */
        dma_addr_t              daddr;  /* physical addr of desc */
        struct sk_buff          *skb;   /* skbuff for buf */
index b65b4fe..941b511 100644 (file)
@@ -80,8 +80,6 @@ int ath5k_hw_stop_rx_dma(struct ath5k_hw *ah)
  * ath5k_hw_get_rxdp - Get RX Descriptor's address
  *
  * @ah: The &struct ath5k_hw
- *
- * XXX: Is RXDP read and clear ?
  */
 u32 ath5k_hw_get_rxdp(struct ath5k_hw *ah)
 {