qcacmn: Properly handle RX REO reinject packets

Currently for REO reinject path, first fragment is in the
linear part of the skb buffer while other fragments are
appended to skb buffer as non-linear paged data. The other
point is that for REO reinject buffer, l3_header_padding is
not there, meaning ethernet header is right after struct
rx_pkt_tlvs.

Above implementation will have issues when WLAN IPA path is
enabled.

Firstly, IPA assumes data buffers are linear. Thus need to
linearize skb buffer before reinjecting into REO.

Secondly, when WLAN does IPA pipe connection, RX pkt offset
is hard-coded to RX_PKT_TLVS_LEN + L3_HEADER_PADDING. Thus
need to pad L3_HEADER_PADDING before ethernet header and
after struct rx_pkt_tlvs.

Change-Id: I36d41bc91d28c2580775a1d2e431e139ff02e19e
CRs-Fixed: 2469315

dp/wifi3.0/dp_ipa.c

@@ -1759,4 +1759,56 @@ bool dp_ipa_is_mdm_platform(void)
 }
 #endif
 
+/**
+ * dp_ipa_handle_rx_reo_reinject - Handle RX REO reinject skb buffer
+ * @soc: soc
+ * @nbuf: skb
+ *
+ * Return: nbuf if success and otherwise NULL
+ */
+qdf_nbuf_t dp_ipa_handle_rx_reo_reinject(struct dp_soc *soc, qdf_nbuf_t nbuf)
+{
+	uint8_t *rx_pkt_tlvs;
+	bool reo_remapped;
+
+	if (!wlan_cfg_is_ipa_enabled(soc->wlan_cfg_ctx))
+		return nbuf;
+
+	qdf_spin_lock_bh(&soc->remap_lock);
+	reo_remapped = soc->reo_remapped;
+	qdf_spin_unlock_bh(&soc->remap_lock);
+
+	/* WLAN IPA is run-time disabled */
+	if (!reo_remapped)
+		return nbuf;
+
+	/* Linearize the skb since IPA assumes linear buffer */
+	if (qdf_likely(qdf_nbuf_is_frag(nbuf))) {
+		if (qdf_nbuf_linearize(nbuf)) {
+			dp_err_rl("nbuf linearize failed");
+			return NULL;
+		}
+	}
+
+	rx_pkt_tlvs = qdf_mem_malloc(RX_PKT_TLVS_LEN);
+	if (!rx_pkt_tlvs) {
+		dp_err_rl("rx_pkt_tlvs alloc failed");
+		return NULL;
+	}
+
+	qdf_mem_copy(rx_pkt_tlvs, qdf_nbuf_data(nbuf), RX_PKT_TLVS_LEN);
+
+	/* Pad L3_HEADER_PADDING before ethhdr and after rx_pkt_tlvs */
+	qdf_nbuf_push_head(nbuf, L3_HEADER_PADDING);
+
+	qdf_mem_copy(qdf_nbuf_data(nbuf), rx_pkt_tlvs, RX_PKT_TLVS_LEN);
+
+	/* L3_HEADDING_PADDING is not accounted for real skb length */
+	qdf_nbuf_set_len(nbuf, qdf_nbuf_len(nbuf) - L3_HEADER_PADDING);
+
+	qdf_mem_free(rx_pkt_tlvs);
+
+	return nbuf;
+}
+
 #endif