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Commit c406ea7c authored by Vladimir Kondratiev's avatar Vladimir Kondratiev Committed by Kalle Valo
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wil6210: Align Rx frames on 4*n+2 by having SNAP 



For the networking code and for hardware network accelerators,
it is better to have IP header 4*n aligned. On the other side,
DMA on Rx path require buffer to be aligned on 4*n as well.
Having 14 bytes of Ethernet header, these 2 alignment
requests are in contradiction.

To solve this, order hardware offload block to not remove
SNAP header. This adds extra 6 bytes between addresses and
ethertype, making it 20 bytes total. This way, both buffer and
IP header are 4*n aligned. Remaining is only to remove SNAP
by shifting addresses 6 bytes. This involves data copying, so
this feature should be disabled unless required by the platform.

Module parameter "rx_align_2" (bool, default - false)
introduced to control this feature. Feature is completely disabled
when parameter is false.

Signed-off-by: default avatarVladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
parent cec94d8c

drivers/net/wireless/ath/wil6210/txrx.c

+24 −3
Original line number Diff line number Diff line
@@ -33,6 +33,15 @@ module_param(rtap_include_phy_info, bool, S_IRUGO); 
MODULE_PARM_DESC(rtap_include_phy_info,

		 " Include PHY info in the radiotap header, default - no");



bool rx_align_2;

module_param(rx_align_2, bool, S_IRUGO);

MODULE_PARM_DESC(rx_align_2, " align Rx buffers on 4*n+2, default - no");



static inline uint wil_rx_snaplen(void)

{

	return rx_align_2 ? 6 : 0;

}



static inline int wil_vring_is_empty(struct vring *vring)

{

	return vring->swhead == vring->swtail;
@@ -209,7 +218,7 @@ static int wil_vring_alloc_skb(struct wil6210_priv *wil, struct vring *vring, 
			       u32 i, int headroom)

{

	struct device *dev = wil_to_dev(wil);

	unsigned int sz = mtu_max + ETH_HLEN;

	unsigned int sz = mtu_max + ETH_HLEN + wil_rx_snaplen();

	struct vring_rx_desc dd, *d = &dd;

	volatile struct vring_rx_desc *_d = &vring->va[i].rx;

	dma_addr_t pa;
@@ -365,7 +374,8 @@ static struct sk_buff *wil_vring_reap_rx(struct wil6210_priv *wil, 
	struct vring_rx_desc *d;

	struct sk_buff *skb;

	dma_addr_t pa;

	unsigned int sz = mtu_max + ETH_HLEN;

	unsigned int snaplen = wil_rx_snaplen();

	unsigned int sz = mtu_max + ETH_HLEN + snaplen;

	u16 dmalen;

	u8 ftype;

	int cid;
@@ -438,7 +448,7 @@ static struct sk_buff *wil_vring_reap_rx(struct wil6210_priv *wil, 
		return NULL;

	}



	if (unlikely(skb->len < ETH_HLEN)) {

	if (unlikely(skb->len < ETH_HLEN + snaplen)) {

		wil_err(wil, "Short frame, len = %d\n", skb->len);

		/* TODO: process it (i.e. BAR) */

		kfree_skb(skb);
@@ -460,6 +470,17 @@ static struct sk_buff *wil_vring_reap_rx(struct wil6210_priv *wil, 
		 */

	}



	if (snaplen) {

		/* Packet layout

		 * +-------+-------+---------+------------+------+

		 * | SA(6) | DA(6) | SNAP(6) | ETHTYPE(2) | DATA |

		 * +-------+-------+---------+------------+------+

		 * Need to remove SNAP, shifting SA and DA forward

		 */

		memmove(skb->data + snaplen, skb->data, 2 * ETH_ALEN);

		skb_pull(skb, snaplen);

	}



	return skb;

}

drivers/net/wireless/ath/wil6210/wil6210.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ extern unsigned int mtu_max; 
extern unsigned short rx_ring_overflow_thrsh;

extern int agg_wsize;

extern u32 vring_idle_trsh;

extern bool rx_align_2;



#define WIL_NAME "wil6210"

#define WIL_FW_NAME "wil6210.fw" /* code */

drivers/net/wireless/ath/wil6210/wmi.c

+5 −0
Original line number Diff line number Diff line
@@ -1109,6 +1109,11 @@ int wmi_rx_chain_add(struct wil6210_priv *wil, struct vring *vring) 
		 */

		cmd.l3_l4_ctrl |= (1 << L3_L4_CTRL_TCPIP_CHECKSUM_EN_POS);

	}



	if (rx_align_2)

		cmd.l2_802_3_offload_ctrl |=

				L2_802_3_OFFLOAD_CTRL_SNAP_KEEP_MSK;



	/* typical time for secure PCP is 840ms */

	rc = wmi_call(wil, WMI_CFG_RX_CHAIN_CMDID, &cmd, sizeof(cmd),

		      WMI_CFG_RX_CHAIN_DONE_EVENTID, &evt, sizeof(evt), 2000);

drivers/net/wireless/ath/wil6210/wmi.h

+3 −0
Original line number Diff line number Diff line
@@ -687,6 +687,9 @@ struct wmi_cfg_rx_chain_cmd { 
	#define L2_802_3_OFFLOAD_CTRL_VLAN_TAG_INSERTION_POS (0)

	#define L2_802_3_OFFLOAD_CTRL_VLAN_TAG_INSERTION_LEN (1)

	#define L2_802_3_OFFLOAD_CTRL_VLAN_TAG_INSERTION_MSK (0x1)

	#define L2_802_3_OFFLOAD_CTRL_SNAP_KEEP_POS (1)

	#define L2_802_3_OFFLOAD_CTRL_SNAP_KEEP_LEN (1)

	#define L2_802_3_OFFLOAD_CTRL_SNAP_KEEP_MSK (0x2)

	u8 l2_802_3_offload_ctrl;



	#define L2_NWIFI_OFFLOAD_CTRL_REMOVE_QOS_POS (0)