From patchwork Mon May 10 15:39:08 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mike Frysinger X-Patchwork-Id: 52101 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 07C83B7D5B for ; Tue, 11 May 2010 01:36:43 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753326Ab0EJPgX (ORCPT ); Mon, 10 May 2010 11:36:23 -0400 Received: from smtp.gentoo.org ([140.211.166.183]:43477 "EHLO smtp.gentoo.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751397Ab0EJPgV (ORCPT ); Mon, 10 May 2010 11:36:21 -0400 Received: from vapier-m (localhost [127.0.0.1]) by smtp.gentoo.org (Postfix) with ESMTP id E57B51B401D; Mon, 10 May 2010 15:36:20 +0000 (UTC) From: Mike Frysinger To: netdev@vger.kernel.org, "David S. Miller" Cc: uclinux-dist-devel@blackfin.uclinux.org, Sonic Zhang Subject: [PATCH 3/9] netdev: bfin_mac: invalid data cache only once for each new rx skb buffer Date: Mon, 10 May 2010 11:39:08 -0400 Message-Id: <1273505954-32588-3-git-send-email-vapier@gentoo.org> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1273505954-32588-1-git-send-email-vapier@gentoo.org> References: <1273505954-32588-1-git-send-email-vapier@gentoo.org> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org 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);