linux/drivers/net/wireless/mwifiex/sta_tx.c
Yogesh Ashok Powar e156103cee mwifiex: 4-byte alignment in mwifiex_process_sta_txpd()
In XMIT path, the skb that we get from the kernel itself is not
aligned with 4-byte boundary on some embedded platforms.

Had it not been the presence of tx_pkt_offset field in txpd, 4 byte
memory alignment was not possible without memmove of entire skb.
And that would have increased MIPS instead of reducing.

With this patch few memory cycles can be saved while fetching
interface header and txpd structure because of 4 bytes memory
alignment.

Reported-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Yogesh Ashok Powar <yogeshp@marvell.com>
Tested-by: Philip Rakity <prakity@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2011-07-08 11:47:16 -04:00

204 lines
5.6 KiB
C

/*
* Marvell Wireless LAN device driver: station TX data handling
*
* Copyright (C) 2011, Marvell International Ltd.
*
* This software file (the "File") is distributed by Marvell International
* Ltd. under the terms of the GNU General Public License Version 2, June 1991
* (the "License"). You may use, redistribute and/or modify this File in
* accordance with the terms and conditions of the License, a copy of which
* is available by writing to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or on the
* worldwide web at http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt.
*
* THE FILE IS DISTRIBUTED AS-IS, WITHOUT WARRANTY OF ANY KIND, AND THE
* IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE
* ARE EXPRESSLY DISCLAIMED. The License provides additional details about
* this warranty disclaimer.
*/
#include "decl.h"
#include "ioctl.h"
#include "util.h"
#include "fw.h"
#include "main.h"
#include "wmm.h"
/*
* This function fills the TxPD for tx packets.
*
* The Tx buffer received by this function should already have the
* header space allocated for TxPD.
*
* This function inserts the TxPD in between interface header and actual
* data and adjusts the buffer pointers accordingly.
*
* The following TxPD fields are set by this function, as required -
* - BSS number
* - Tx packet length and offset
* - Priority
* - Packet delay
* - Priority specific Tx control
* - Flags
*/
void *mwifiex_process_sta_txpd(struct mwifiex_private *priv,
struct sk_buff *skb)
{
struct mwifiex_adapter *adapter = priv->adapter;
struct txpd *local_tx_pd;
struct mwifiex_txinfo *tx_info = MWIFIEX_SKB_TXCB(skb);
u8 pad;
if (!skb->len) {
dev_err(adapter->dev, "Tx: bad packet length: %d\n",
skb->len);
tx_info->status_code = -1;
return skb->data;
}
/* If skb->data is not aligned; add padding */
pad = (4 - (((void *)skb->data - NULL) & 0x3)) % 4;
BUG_ON(skb_headroom(skb) < (sizeof(*local_tx_pd) + INTF_HEADER_LEN
+ pad));
skb_push(skb, sizeof(*local_tx_pd) + pad);
local_tx_pd = (struct txpd *) skb->data;
memset(local_tx_pd, 0, sizeof(struct txpd));
local_tx_pd->bss_num = priv->bss_num;
local_tx_pd->bss_type = priv->bss_type;
local_tx_pd->tx_pkt_length = cpu_to_le16((u16) (skb->len -
(sizeof(struct txpd) + pad)));
local_tx_pd->priority = (u8) skb->priority;
local_tx_pd->pkt_delay_2ms =
mwifiex_wmm_compute_drv_pkt_delay(priv, skb);
if (local_tx_pd->priority <
ARRAY_SIZE(priv->wmm.user_pri_pkt_tx_ctrl))
/*
* Set the priority specific tx_control field, setting of 0 will
* cause the default value to be used later in this function
*/
local_tx_pd->tx_control =
cpu_to_le32(priv->wmm.user_pri_pkt_tx_ctrl[local_tx_pd->
priority]);
if (adapter->pps_uapsd_mode) {
if (mwifiex_check_last_packet_indication(priv)) {
adapter->tx_lock_flag = true;
local_tx_pd->flags =
MWIFIEX_TxPD_POWER_MGMT_LAST_PACKET;
}
}
/* Offset of actual data */
local_tx_pd->tx_pkt_offset = cpu_to_le16(sizeof(struct txpd) + pad);
/* make space for INTF_HEADER_LEN */
skb_push(skb, INTF_HEADER_LEN);
if (!local_tx_pd->tx_control)
/* TxCtrl set by user or default */
local_tx_pd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);
return skb->data;
}
/*
* This function tells firmware to send a NULL data packet.
*
* The function creates a NULL data packet with TxPD and sends to the
* firmware for transmission, with highest priority setting.
*/
int mwifiex_send_null_packet(struct mwifiex_private *priv, u8 flags)
{
struct mwifiex_adapter *adapter = priv->adapter;
struct txpd *local_tx_pd;
/* sizeof(struct txpd) + Interface specific header */
#define NULL_PACKET_HDR 64
u32 data_len = NULL_PACKET_HDR;
struct sk_buff *skb;
int ret;
struct mwifiex_txinfo *tx_info = NULL;
if (adapter->surprise_removed)
return -1;
if (!priv->media_connected)
return -1;
if (adapter->data_sent)
return -1;
skb = dev_alloc_skb(data_len);
if (!skb)
return -1;
tx_info = MWIFIEX_SKB_TXCB(skb);
tx_info->bss_index = priv->bss_index;
skb_reserve(skb, sizeof(struct txpd) + INTF_HEADER_LEN);
skb_push(skb, sizeof(struct txpd));
local_tx_pd = (struct txpd *) skb->data;
local_tx_pd->tx_control = cpu_to_le32(priv->pkt_tx_ctrl);
local_tx_pd->flags = flags;
local_tx_pd->priority = WMM_HIGHEST_PRIORITY;
local_tx_pd->tx_pkt_offset = cpu_to_le16(sizeof(struct txpd));
local_tx_pd->bss_num = priv->bss_num;
local_tx_pd->bss_type = priv->bss_type;
skb_push(skb, INTF_HEADER_LEN);
ret = adapter->if_ops.host_to_card(adapter, MWIFIEX_TYPE_DATA,
skb->data, skb->len, NULL);
switch (ret) {
case -EBUSY:
adapter->data_sent = true;
/* Fall through FAILURE handling */
case -1:
dev_kfree_skb_any(skb);
dev_err(adapter->dev, "%s: host_to_card failed: ret=%d\n",
__func__, ret);
adapter->dbg.num_tx_host_to_card_failure++;
break;
case 0:
dev_kfree_skb_any(skb);
dev_dbg(adapter->dev, "data: %s: host_to_card succeeded\n",
__func__);
adapter->tx_lock_flag = true;
break;
case -EINPROGRESS:
break;
default:
break;
}
return ret;
}
/*
* This function checks if we need to send last packet indication.
*/
u8
mwifiex_check_last_packet_indication(struct mwifiex_private *priv)
{
struct mwifiex_adapter *adapter = priv->adapter;
u8 ret = false;
if (!adapter->sleep_period.period)
return ret;
if (mwifiex_wmm_lists_empty(adapter))
ret = true;
if (ret && !adapter->cmd_sent && !adapter->curr_cmd
&& !is_command_pending(adapter)) {
adapter->delay_null_pkt = false;
ret = true;
} else {
ret = false;
adapter->delay_null_pkt = true;
}
return ret;
}