Re: [PATCH net-next v5 2/2] net: thunderx: add timestamping support

On Mon, 2017-12-11 at 15:36 -0800, Richard Cochran wrote:

On Mon, Dec 11, 2017 at 05:14:31PM +0300, Aleksey Makarov wrote:

quoted

@@ -880,6 +889,46 @@ static void nic_pause_frame(struct nicpf *nic, int vf, struct pfc *cfg)
 	}
 }
 
+/* Enable or disable HW timestamping by BGX for pkts received on a LMAC */
+static void nic_config_timestamp(struct nicpf *nic, int vf, struct set_ptp *ptp)
+{
+	struct pkind_cfg *pkind;
+	u8 lmac, bgx_idx;
+	u64 pkind_val, pkind_idx;
+
+	if (vf >= nic->num_vf_en)
+		return;
+
+	bgx_idx = NIC_GET_BGX_FROM_VF_LMAC_MAP(nic->vf_lmac_map[vf]);
+	lmac = NIC_GET_LMAC_FROM_VF_LMAC_MAP(nic->vf_lmac_map[vf]);
+
+	pkind_idx = lmac + bgx_idx * MAX_LMAC_PER_BGX;
+	pkind_val = nic_reg_read(nic, NIC_PF_PKIND_0_15_CFG | (pkind_idx << 3));
+	pkind = (struct pkind_cfg *)&pkind_val;
+
+	if (ptp->enable && !pkind->hdr_sl) {
+		/* Skiplen to exclude 8byte timestamp while parsing pkt
+		 * If not configured, will result in L2 errors.
+		 */
+		pkind->hdr_sl = 4;
+		/* Adjust max packet length allowed */
+		pkind->maxlen += (pkind->hdr_sl * 2);

Are all compilers smart enough to set this to 8?
I rather doubt a compiler is even allowed to.