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/rt2500usb.c | 37 +++++++++++++++------------------ 1 file changed, 17 insertions(+), 20 deletions(-) (limited to 'drivers/net/wireless/rt2x00/rt2500usb.c') diff --git a/drivers/net/wireless/rt2x00/rt2500usb.c b/drivers/net/wireless/rt2x00/rt2500usb.c index 9f59db91cfc2..86cd9a5eee2b 100644 --- a/drivers/net/wireless/rt2x00/rt2500usb.c +++ b/drivers/net/wireless/rt2x00/rt2500usb.c @@ -1117,11 +1117,24 @@ static void rt2500usb_fill_rxdone(struct queue_entry *entry, __le32 *rxd = (__le32 *)(entry->skb->data + (priv_rx->urb->actual_length - entry->queue->desc_size)); - struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)entry->skb->data; - int header_size = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control)); + unsigned int offset = entry->queue->desc_size + 2; u32 word0; u32 word1; + /* + * Copy descriptor to the available headroom inside the skbuffer. + * Remove the original copy by trimming the skbuffer. + */ + skb_push(entry->skb, offset); + memcpy(entry->skb->data, rxd, entry->queue->desc_size); + rxd = (__le32 *)entry->skb->data; + skb_pull(entry->skb, offset); + skb_trim(entry->skb, rxdesc->size); + + /* + * The descriptor is now aligned to 4 bytes and thus it is + * now safe to read it on all architectures. + */ rt2x00_desc_read(rxd, 0, &word0); rt2x00_desc_read(rxd, 1, &word1); @@ -1142,28 +1155,12 @@ static void rt2500usb_fill_rxdone(struct queue_entry *entry, rxdesc->my_bss = !!rt2x00_get_field32(word0, RXD_W0_MY_BSS); /* - * The data behind the ieee80211 header must be - * aligned on a 4 byte boundary. - */ - if (header_size % 4 == 0) { - skb_push(entry->skb, 2); - memmove(entry->skb->data, entry->skb->data + 2, - entry->skb->len - 2); - } - - /* - * Set descriptor pointer. + * Set descriptor and data pointer. */ skbdesc->data = entry->skb->data; skbdesc->data_len = rxdesc->size; - skbdesc->desc = entry->skb->data + rxdesc->size; + skbdesc->desc = entry->skb->data - offset; skbdesc->desc_len = entry->queue->desc_size; - - /* - * Remove descriptor from skb buffer and trim the whole thing - * down to only contain data. - */ - skb_trim(entry->skb, rxdesc->size); } /* -- cgit v1.2.3