+#define OPT_HDR(type, skb, off) \
+ (type *)(skb_network_header(skb) + (off))
+
+static void iwl_mvm_tx_csum(struct iwl_mvm *mvm, struct sk_buff *skb,
+ struct ieee80211_hdr *hdr,
+ struct ieee80211_tx_info *info,
+ struct iwl_tx_cmd *tx_cmd)
+{
+#if IS_ENABLED(CONFIG_INET)
+ u16 mh_len = ieee80211_hdrlen(hdr->frame_control);
+ u16 offload_assist = le16_to_cpu(tx_cmd->offload_assist);
+ u8 protocol = 0;
+
+ /*
+ * Do not compute checksum if already computed or if transport will
+ * compute it
+ */
+ if (skb->ip_summed != CHECKSUM_PARTIAL || IWL_MVM_SW_TX_CSUM_OFFLOAD)
+ return;
+
+ /* We do not expect to be requested to csum stuff we do not support */
+ if (WARN_ONCE(!(mvm->hw->netdev_features & IWL_TX_CSUM_NETIF_FLAGS) ||
+ (skb->protocol != htons(ETH_P_IP) &&
+ skb->protocol != htons(ETH_P_IPV6)),
+ "No support for requested checksum\n")) {
+ skb_checksum_help(skb);
+ return;
+ }
+
+ if (skb->protocol == htons(ETH_P_IP)) {
+ protocol = ip_hdr(skb)->protocol;
+ } else {
+#if IS_ENABLED(CONFIG_IPV6)
+ struct ipv6hdr *ipv6h =
+ (struct ipv6hdr *)skb_network_header(skb);
+ unsigned int off = sizeof(*ipv6h);
+
+ protocol = ipv6h->nexthdr;
+ while (protocol != NEXTHDR_NONE && ipv6_ext_hdr(protocol)) {
+ /* only supported extension headers */
+ if (protocol != NEXTHDR_ROUTING &&
+ protocol != NEXTHDR_HOP &&
+ protocol != NEXTHDR_DEST &&
+ protocol != NEXTHDR_FRAGMENT) {
+ skb_checksum_help(skb);
+ return;
+ }
+
+ if (protocol == NEXTHDR_FRAGMENT) {
+ struct frag_hdr *hp =
+ OPT_HDR(struct frag_hdr, skb, off);
+
+ protocol = hp->nexthdr;
+ off += sizeof(struct frag_hdr);
+ } else {
+ struct ipv6_opt_hdr *hp =
+ OPT_HDR(struct ipv6_opt_hdr, skb, off);
+
+ protocol = hp->nexthdr;
+ off += ipv6_optlen(hp);
+ }
+ }
+ /* if we get here - protocol now should be TCP/UDP */
+#endif
+ }
+
+ if (protocol != IPPROTO_TCP && protocol != IPPROTO_UDP) {
+ WARN_ON_ONCE(1);
+ skb_checksum_help(skb);
+ return;
+ }
+
+ /* enable L4 csum */
+ offload_assist |= BIT(TX_CMD_OFFLD_L4_EN);
+
+ /*
+ * Set offset to IP header (snap).
+ * We don't support tunneling so no need to take care of inner header.
+ * Size is in words.
+ */
+ offload_assist |= (4 << TX_CMD_OFFLD_IP_HDR);
+
+ /* Do IPv4 csum for AMSDU only (no IP csum for Ipv6) */
+ if (skb->protocol == htons(ETH_P_IP) &&
+ (offload_assist & BIT(TX_CMD_OFFLD_AMSDU))) {
+ ip_hdr(skb)->check = 0;
+ offload_assist |= BIT(TX_CMD_OFFLD_L3_EN);
+ }
+
+ /* reset UDP/TCP header csum */
+ if (protocol == IPPROTO_TCP)
+ tcp_hdr(skb)->check = 0;
+ else
+ udp_hdr(skb)->check = 0;
+
+ /* mac header len should include IV, size is in words */
+ if (info->control.hw_key)
+ mh_len += info->control.hw_key->iv_len;
+ mh_len /= 2;
+ offload_assist |= mh_len << TX_CMD_OFFLD_MH_SIZE;
+
+ tx_cmd->offload_assist = cpu_to_le16(offload_assist);
+#endif
+}
+