[34-longterm 123/247] p54pci: update receive dma buffers before and after processing

Paul Gortmaker
2011-06-23T18:09:53Z

From: Christian Lamparter <chunkeey@googlemail.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 0bf719dfdecc5552155cbec78e49fa06e531e35c upstream.

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."

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/net/wireless/p54/p54pci.c | 14 +++++++++-----
1 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/net/wireless/p54/p54pci.c b/drivers/net/wireless/p54/p54pci.c
index e1e3972..5735b6b 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);
}

--
1.7.4.4