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Commit b43d63bd authored by RA-Jay Hung's avatar RA-Jay Hung Committed by John W. Linville
Browse files

rt2x00: Fix rt2800 USB TX Path DMA issue 



rt2800usb chips need to add 1~3 bytes zero padding after each 802.11 header & payload,
and at the end need to add 4 bytes zero padding whether doing TX bulk aggregation or not,

TXINFO_W0_USB_DMA_TX_PKT_LEN in TXINFO must include 1-3 bytes padding after 802.11 header & payload
but do not include 4 bytes end zero padding.

In rt2800usb_get_tx_data_len do not consider multiple of the USB packet size case, sometimes this will
cause USB DMA problem.

Signed-off-by: default avatarRA-Jay Hung <jay_hung@ralinktech.com>
Signed-off-by: default avatarIvo van Doorn <IvDoorn@gmail.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent ef8397cf

drivers/net/wireless/rt2x00/rt2800usb.c

+26 −13
Original line number Diff line number Diff line
@@ -307,8 +307,14 @@ static void rt2800usb_write_tx_desc(struct queue_entry *entry, 
	 * Initialize TXINFO descriptor

	 */

	rt2x00_desc_read(txi, 0, &word);



	/*

	 * The size of TXINFO_W0_USB_DMA_TX_PKT_LEN is

	 * TXWI + 802.11 header + L2 pad + payload + pad,

	 * so need to decrease size of TXINFO and USB end pad.

	 */

	rt2x00_set_field32(&word, TXINFO_W0_USB_DMA_TX_PKT_LEN,

			   entry->skb->len - TXINFO_DESC_SIZE);

			   entry->skb->len - TXINFO_DESC_SIZE - 4);

	rt2x00_set_field32(&word, TXINFO_W0_WIV,

			   !test_bit(ENTRY_TXD_ENCRYPT_IV, &txdesc->flags));

	rt2x00_set_field32(&word, TXINFO_W0_QSEL, 2);
@@ -326,22 +332,29 @@ static void rt2800usb_write_tx_desc(struct queue_entry *entry, 
	skbdesc->desc_len = TXINFO_DESC_SIZE + TXWI_DESC_SIZE;

}



/*

 * TX data initialization

 */

static int rt2800usb_get_tx_data_len(struct queue_entry *entry)

static void rt2800usb_write_tx_data(struct queue_entry *entry,

					struct txentry_desc *txdesc)

{

	int length;

	u8 padding_len;



	/*

	 * The length _must_ include 4 bytes padding,

	 * it should always be multiple of 4,

	 * but it must _not_ be a multiple of the USB packet size.

	 * pad(1~3 bytes) is added after each 802.11 payload.

	 * USB end pad(4 bytes) is added at each USB bulk out packet end.

	 * TX frame format is :

	 * | TXINFO | TXWI | 802.11 header | L2 pad | payload | pad | USB end pad |

	 *                 |<------------- tx_pkt_len ------------->|

	 */

	length = roundup(entry->skb->len + 4, 4);

	length += (4 * !(length % entry->queue->usb_maxpacket));

        rt2800_write_tx_data(entry, txdesc);

        padding_len = roundup(entry->skb->len + 4, 4) - entry->skb->len;

        memset(skb_put(entry->skb, padding_len), 0, padding_len);

}



	return length;

/*

 * TX data initialization

 */

static int rt2800usb_get_tx_data_len(struct queue_entry *entry)

{

	return entry->skb->len;

}



/*
@@ -579,7 +592,7 @@ static const struct rt2x00lib_ops rt2800usb_rt2x00_ops = { 
	.link_tuner		= rt2800_link_tuner,

	.watchdog		= rt2800usb_watchdog,

	.write_tx_desc		= rt2800usb_write_tx_desc,

	.write_tx_data		= rt2800_write_tx_data,

	.write_tx_data		= rt2800usb_write_tx_data,

	.write_beacon		= rt2800_write_beacon,

	.get_tx_data_len	= rt2800usb_get_tx_data_len,

	.kick_tx_queue		= rt2x00usb_kick_tx_queue,