From f855c10b6e7b0c448c35b88266f788dd3738375e Mon Sep 17 00:00:00 2001 From: Ivo van Doorn Date: Sun, 9 Mar 2008 22:38:18 +0100 Subject: rt2x00: Align RX descriptor to 4 bytes Some architectures give problems when reading RX frame descriptor words when the descriptor is not aligned on a 4 byte boundrary. Due to optimalizations for the ieee80211 payload 4 byte alignment, it is no longer guarenteed that the descriptor is placed on the 4 byte boundrary (In fact, for rt73usb it is absolutely never aligned to 4 bytes, for rt2500usb it depends on the length of the payload). This will copy the descriptor to a 4 byte aligned location before it is read for the first time. This will also move the payload data alignment in rt2x00usb (instead of inside the driver) where it has always belonged. Signed-off-by: Ivo van Doorn Signed-off-by: John W. Linville --- drivers/net/wireless/rt2x00/rt2x00usb.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'drivers/net/wireless/rt2x00/rt2x00usb.c') diff --git a/drivers/net/wireless/rt2x00/rt2x00usb.c b/drivers/net/wireless/rt2x00/rt2x00usb.c index 063b167da31e..512ff3914813 100644 --- a/drivers/net/wireless/rt2x00/rt2x00usb.c +++ b/drivers/net/wireless/rt2x00/rt2x00usb.c @@ -247,11 +247,11 @@ static struct sk_buff* rt2x00usb_alloc_rxskb(struct data_queue *queue) * advance. */ frame_size = queue->data_size + queue->desc_size; - skb = dev_alloc_skb(frame_size + 2); + skb = dev_alloc_skb(queue->desc_size + frame_size + 2); if (!skb) return NULL; - skb_reserve(skb, 2); + skb_reserve(skb, queue->desc_size + 2); skb_put(skb, frame_size); return skb; @@ -264,6 +264,7 @@ static void rt2x00usb_interrupt_rxdone(struct urb *urb) struct sk_buff *skb; struct skb_frame_desc *skbdesc; struct rxdone_entry_desc rxdesc; + int header_size; if (!test_bit(DEVICE_ENABLED_RADIO, &rt2x00dev->flags) || !test_and_clear_bit(ENTRY_OWNER_DEVICE_DATA, &entry->flags)) @@ -287,6 +288,18 @@ static void rt2x00usb_interrupt_rxdone(struct urb *urb) memset(&rxdesc, 0, sizeof(rxdesc)); rt2x00dev->ops->lib->fill_rxdone(entry, &rxdesc); + /* + * The data behind the ieee80211 header must be + * aligned on a 4 byte boundary. + */ + header_size = ieee80211_get_hdrlen_from_skb(entry->skb); + if (header_size % 4 == 0) { + skb_push(entry->skb, 2); + memmove(entry->skb->data, entry->skb->data + 2, + entry->skb->len - 2); + skbdesc->data = entry->skb->data; + } + /* * Allocate a new sk buffer to replace the current one. * If allocation fails, we should drop the current frame -- cgit v1.2.3