From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Frysinger Subject: [PATCH 03/11] netdev: bfin_mac: invalid data cache only once for each new rx skb buffer Date: Sun, 9 May 2010 06:18:49 -0400 Message-ID: <1273400337-26501-3-git-send-email-vapier@gentoo.org> References: <1273400337-26501-1-git-send-email-vapier@gentoo.org> Cc: uclinux-dist-devel@blackfin.uclinux.org, Sonic Zhang To: netdev@vger.kernel.org, "David S. Miller" Return-path: Received: from smtp.gentoo.org ([140.211.166.183]:53236 "EHLO smtp.gentoo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752381Ab0EIKQI (ORCPT ); Sun, 9 May 2010 06:16:08 -0400 In-Reply-To: <1273400337-26501-1-git-send-email-vapier@gentoo.org> Sender: netdev-owner@vger.kernel.org List-ID: From: Sonic Zhang The skb buffer isn't actually used until we finish transferring and pass it up to higher layers, so only invalidate the range once before we start receiving actual data. This also avoids the problem with data invalidating on Blackfin systems -- there is no invalidate-only, just invalidate+flush. So when running in writeback mode, there is the small (but not uncommon) possibility of the flush overwriting valid DMA-ed data from the cache. Signed-off-by: Sonic Zhang Signed-off-by: Mike Frysinger --- drivers/net/bfin_mac.c | 13 ++++++++----- 1 files changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/net/bfin_mac.c b/drivers/net/bfin_mac.c index c888465..f9ba598 100644 --- a/drivers/net/bfin_mac.c +++ b/drivers/net/bfin_mac.c @@ -203,6 +203,11 @@ static int desc_list_init(void) goto init_error; } skb_reserve(new_skb, NET_IP_ALIGN); + /* Invidate the data cache of skb->data range when it is write back + * cache. It will prevent overwritting the new data from DMA + */ + blackfin_dcache_invalidate_range((unsigned long)new_skb->head, + (unsigned long)new_skb->end); r->skb = new_skb; /* @@ -1012,19 +1017,17 @@ static void bfin_mac_rx(struct net_device *dev) } /* reserve 2 bytes for RXDWA padding */ skb_reserve(new_skb, NET_IP_ALIGN); - current_rx_ptr->skb = new_skb; - current_rx_ptr->desc_a.start_addr = (unsigned long)new_skb->data - 2; - /* Invidate the data cache of skb->data range when it is write back * cache. It will prevent overwritting the new data from DMA */ blackfin_dcache_invalidate_range((unsigned long)new_skb->head, (unsigned long)new_skb->end); + current_rx_ptr->skb = new_skb; + current_rx_ptr->desc_a.start_addr = (unsigned long)new_skb->data - 2; + len = (unsigned short)((current_rx_ptr->status.status_word) & RX_FRLEN); skb_put(skb, len); - blackfin_dcache_invalidate_range((unsigned long)skb->head, - (unsigned long)skb->tail); skb->protocol = eth_type_trans(skb, dev); -- 1.7.1