Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:61641 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750794Ab1BKAsn (ORCPT ); Thu, 10 Feb 2011 19:48:43 -0500 Received: by fxm20 with SMTP id 20so2116442fxm.19 for ; Thu, 10 Feb 2011 16:48:42 -0800 (PST) From: Christian Lamparter To: linux-wireless@vger.kernel.org Subject: [PATCH for-2.6.38] p54pci: update receive dma buffers before and after processing Date: Fri, 11 Feb 2011 01:48:42 +0100 Cc: linville@tuxdriver.com MIME-Version: 1.0 Content-Type: Text/Plain; charset="us-ascii" Message-Id: <201102110148.43155.chunkeey@googlemail.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: Documentation/DMA-API-HOWTO.txt states: "DMA transfers need to be synced properly in order for the cpu and device to see the most uptodate and correct copy of the DMA buffer." Cc: Signed-off-by: Christian Lamparter --- Embarrassingly, this bug is unique to p54 and has been around since 2.6.25. This tells us something interesting about our userbase. --- diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c index 1eacba4..0494d7b 100644 --- a/drivers/net/wireless/p54/p54pci.c +++ b/drivers/net/wireless/p54/p54pci.c @@ -199,6 +199,7 @@ static void p54p_check_rx_ring(struct ieee80211_hw *dev, u32 *index, while (i != idx) { u16 len; struct sk_buff *skb; + dma_addr_t dma_addr; desc = &ring[i]; len = le16_to_cpu(desc->len); skb = rx_buf[i]; @@ -216,17 +217,20 @@ static void p54p_check_rx_ring(struct ieee80211_hw *dev, u32 *index, len = priv->common.rx_mtu; } + dma_addr = le32_to_cpu(desc->host_addr); + pci_dma_sync_single_for_cpu(priv->pdev, dma_addr, + priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE); skb_put(skb, len); if (p54_rx(dev, skb)) { - pci_unmap_single(priv->pdev, - le32_to_cpu(desc->host_addr), - priv->common.rx_mtu + 32, - PCI_DMA_FROMDEVICE); + pci_unmap_single(priv->pdev, dma_addr, + priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE); rx_buf[i] = NULL; - desc->host_addr = 0; + desc->host_addr = cpu_to_le32(0); } else { skb_trim(skb, 0); + pci_dma_sync_single_for_device(priv->pdev, dma_addr, + priv->common.rx_mtu + 32, PCI_DMA_FROMDEVICE); desc->len = cpu_to_le16(priv->common.rx_mtu + 32); }