qcacmn: wifi DP TX optimization for RMNET pkts

pkts from rmnet device are sent as SG, we see poor
throughput when transmitting these SG frames using
an MSDU extension descriptor. to resolve this issue
we identify if the frame is from RMNET device and if so
copy the headers from skb linear address to the frag
address and provide the frag address to HW for transmission

CRs-Fixed: 3337822
Change-Id: Ic1b7d9f861dcd4f838509772c45e47d3917fc59f

dp/wifi3.0/dp_tx.c

@@ -2001,6 +2001,70 @@ void dp_tx_nbuf_unmap_regular(struct dp_soc *soc, struct dp_tx_desc_s *desc)
 					   desc->length);
 }
 
+#ifdef QCA_DP_TX_RMNET_OPTIMIZATION
+static inline bool
+is_nbuf_frm_rmnet(qdf_nbuf_t nbuf, struct dp_tx_msdu_info_s *msdu_info)
+{
+	struct net_device *ingress_dev;
+	skb_frag_t *frag;
+	uint16_t buf_len = 0;
+	uint16_t linear_data_len = 0;
+	uint8_t *payload_addr = NULL;
+
+	ingress_dev = dev_get_by_index(dev_net(nbuf->dev), nbuf->skb_iif);
+
+	if ((ingress_dev->priv_flags & IFF_PHONY_HEADROOM)) {
+		dev_put(ingress_dev);
+		frag = &(skb_shinfo(nbuf)->frags[0]);
+		buf_len = skb_frag_size(frag);
+		payload_addr = (uint8_t *)skb_frag_address(frag);
+		linear_data_len = skb_headlen(nbuf);
+
+		buf_len += linear_data_len;
+		payload_addr = payload_addr - linear_data_len;
+		memcpy(payload_addr, nbuf->data, linear_data_len);
+
+		msdu_info->frm_type = dp_tx_frm_rmnet;
+		msdu_info->buf_len = buf_len;
+		msdu_info->payload_addr = payload_addr;
+
+		return true;
+	}
+	dev_put(ingress_dev);
+	return false;
+}
+
+static inline
+qdf_dma_addr_t dp_tx_rmnet_nbuf_map(struct dp_tx_msdu_info_s *msdu_info,
+				    struct dp_tx_desc_s *tx_desc)
+{
+	qdf_dma_addr_t paddr;
+
+	paddr = (qdf_dma_addr_t)qdf_mem_virt_to_phys(msdu_info->payload_addr);
+	tx_desc->length  = msdu_info->buf_len;
+
+	qdf_nbuf_dma_clean_range((void *)msdu_info->payload_addr,
+				 (void *)(msdu_info->payload_addr +
+					  msdu_info->buf_len));
+
+	tx_desc->flags |= DP_TX_DESC_FLAG_RMNET;
+	return paddr;
+}
+#else
+static inline bool
+is_nbuf_frm_rmnet(qdf_nbuf_t nbuf, struct dp_tx_msdu_info_s *msdu_info)
+{
+	return false;
+}
+
+static inline
+qdf_dma_addr_t dp_tx_rmnet_nbuf_map(struct dp_tx_msdu_info_s *msdu_info,
+				    struct dp_tx_desc_s *tx_desc)
+{
+	return 0;
+}
+#endif
+
 #if defined(QCA_DP_TX_NBUF_NO_MAP_UNMAP) && !defined(BUILD_X86)
 static inline
 qdf_dma_addr_t dp_tx_nbuf_map(struct dp_vdev *vdev,
@@ -2020,7 +2084,8 @@ static inline
 void dp_tx_nbuf_unmap(struct dp_soc *soc,
 		      struct dp_tx_desc_s *desc)
 {
-	if (qdf_unlikely(!(desc->flags & DP_TX_DESC_FLAG_SIMPLE)))
+	if (qdf_unlikely(!(desc->flags &
+			   (DP_TX_DESC_FLAG_SIMPLE | DP_TX_DESC_FLAG_RMNET))))
 		return dp_tx_nbuf_unmap_regular(soc, desc);
 }
 #else
@@ -2322,7 +2387,11 @@ dp_tx_send_msdu_single(struct dp_vdev *vdev, qdf_nbuf_t nbuf,
 
 	dp_tx_update_mesh_flags(soc, vdev, tx_desc);
 
-	paddr =  dp_tx_nbuf_map(vdev, tx_desc, nbuf);
+	if (qdf_unlikely(msdu_info->frm_type == dp_tx_frm_rmnet))
+		paddr = dp_tx_rmnet_nbuf_map(msdu_info, tx_desc);
+	else
+		paddr =  dp_tx_nbuf_map(vdev, tx_desc, nbuf);
+
 	if (!paddr) {
 		/* Handle failure */
 		dp_err("qdf_nbuf_map failed");
@@ -3612,6 +3681,9 @@ qdf_nbuf_t dp_tx_send(struct cdp_soc_t *soc_hdl, uint8_t vdev_id,
 		} else {
 			struct dp_tx_seg_info_s seg_info = {0};
 
+			if (qdf_unlikely(is_nbuf_frm_rmnet(nbuf, &msdu_info)))
+				goto send_single;
+
 			nbuf = dp_tx_prepare_sg(vdev, nbuf, &seg_info,
 						&msdu_info);
 			if (!nbuf)
@@ -3670,6 +3742,7 @@ qdf_nbuf_t dp_tx_send(struct cdp_soc_t *soc_hdl, uint8_t vdev_id,
 				 1, qdf_nbuf_len(nbuf));
 	}
 
+send_single:
 	/*  Single linear frame */
 	/*
 	 * If nbuf is a simple linear frame, use send_single function to