net: ethernet: ti: am65-cpsw/ethtool: Enable RX HW timestamp only for PTP packets

In the current mechanism of timestamping, am65-cpsw-nuss driver
enables hardware timestamping for all received packets by setting
the TSTAMP_EN bit in CPTS_CONTROL register, which directs the CPTS
module to timestamp all received packets, followed by passing
timestamp via DMA descriptors. This mechanism causes CPSW Port to
Lock up.

To prevent port lock up, don't enable rx packet timestamping by
setting TSTAMP_EN bit in CPTS_CONTROL register. The workaround for
timestamping received packets is to utilize the CPTS Event FIFO
that records timestamps corresponding to certain events. The CPTS
module is configured to generate timestamps for Multicast Ethernet,
UDP/IPv4 and UDP/IPv6 PTP packets.

Update supported hwtstamp_rx_filters values for CPSW's timestamping
capability.

Fixes: b1f66a5bee07 ("net: ethernet: ti: am65-cpsw-nuss: enable packet timestamping support")
Signed-off-by: Chintan Vankar <[e-mail]>
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/ethernet/ti/am65-cpsw-ethtool.c

···
 					 struct ethtool_ts_info *info)
 {
 	struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
+	unsigned int ptp_v2_filter;
+
+	ptp_v2_filter = BIT(HWTSTAMP_FILTER_PTP_V2_L4_EVENT)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_L4_SYNC)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ) |
+			BIT(HWTSTAMP_FILTER_PTP_V2_L2_EVENT)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_L2_SYNC)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_L2_DELAY_REQ) |
+			BIT(HWTSTAMP_FILTER_PTP_V2_EVENT)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_SYNC)	 |
+			BIT(HWTSTAMP_FILTER_PTP_V2_DELAY_REQ);
 
 	if (!IS_ENABLED(CONFIG_TI_K3_AM65_CPTS))
 		return ethtool_op_get_ts_info(ndev, info);
···
 		SOF_TIMESTAMPING_RAW_HARDWARE;
 	info->phc_index = am65_cpts_phc_index(common->cpts);
 	info->tx_types = BIT(HWTSTAMP_TX_OFF) | BIT(HWTSTAMP_TX_ON);
-	info->rx_filters = BIT(HWTSTAMP_FILTER_NONE) | BIT(HWTSTAMP_FILTER_ALL);
+	info->rx_filters = BIT(HWTSTAMP_FILTER_NONE) | ptp_v2_filter;
 	return 0;
 }
 

drivers/net/ethernet/ti/am65-cpsw-nuss.c

···
 #define AM65_CPSW_PN_TS_CTL_TX_HOST_TS_EN	BIT(11)
 #define AM65_CPSW_PN_TS_CTL_MSG_TYPE_EN_SHIFT	16
 
+#define AM65_CPSW_PN_TS_CTL_RX_ANX_F_EN		BIT(0)
+#define AM65_CPSW_PN_TS_CTL_RX_VLAN_LT1_EN	BIT(1)
+#define AM65_CPSW_PN_TS_CTL_RX_VLAN_LT2_EN	BIT(2)
+#define AM65_CPSW_PN_TS_CTL_RX_ANX_D_EN		BIT(3)
+#define AM65_CPSW_PN_TS_CTL_RX_ANX_E_EN		BIT(9)
+
 /* AM65_CPSW_PORTN_REG_TS_SEQ_LTYPE_REG register fields */
 #define AM65_CPSW_PN_TS_SEQ_ID_OFFSET_SHIFT	16
 
···
 	(AM65_CPSW_PN_TS_CTL_TX_ANX_D_EN |	\
 	 AM65_CPSW_PN_TS_CTL_TX_ANX_E_EN |	\
 	 AM65_CPSW_PN_TS_CTL_TX_ANX_F_EN)
+
+#define AM65_CPSW_TS_RX_ANX_ALL_EN		\
+	(AM65_CPSW_PN_TS_CTL_RX_ANX_D_EN |	\
+	 AM65_CPSW_PN_TS_CTL_RX_ANX_E_EN |	\
+	 AM65_CPSW_PN_TS_CTL_RX_ANX_F_EN)
 
 #define AM65_CPSW_ALE_AGEOUT_DEFAULT	30
 /* Number of TX/RX descriptors */
···
 	return ret;
 }
 
-static void am65_cpsw_nuss_rx_ts(struct sk_buff *skb, u32 *psdata)
-{
-	struct skb_shared_hwtstamps *ssh;
-	u64 ns;
-
-	ns = ((u64)psdata[1] << 32) | psdata[0];
-
-	ssh = skb_hwtstamps(skb);
-	memset(ssh, 0, sizeof(*ssh));
-	ssh->hwtstamp = ns_to_ktime(ns);
-}
-
 /* RX psdata[2] word format - checksum information */
 #define AM65_CPSW_RX_PSD_CSUM_ADD	GENMASK(15, 0)
 #define AM65_CPSW_RX_PSD_CSUM_ERR	BIT(16)
···
 		skb_reserve(skb, headroom);
 	}
 
-	/* Pass skb to netstack if no XDP prog or returned XDP_PASS */
-	if (port->rx_ts_enabled)
-		am65_cpsw_nuss_rx_ts(skb, psdata);
-
 	ndev_priv = netdev_priv(ndev);
 	am65_cpsw_nuss_set_offload_fwd_mark(skb, ndev_priv->offload_fwd_mark);
 	skb_put(skb, pkt_len);
+	if (port->rx_ts_enabled)
+		am65_cpts_rx_timestamp(common->cpts, skb);
 	skb_mark_for_recycle(skb);
 	skb->protocol = eth_type_trans(skb, ndev);
 	am65_cpsw_nuss_rx_csum(skb, csum_info);
···
 static int am65_cpsw_nuss_hwtstamp_set(struct net_device *ndev,
 				       struct ifreq *ifr)
 {
-	struct am65_cpsw_common *common = am65_ndev_to_common(ndev);
 	struct am65_cpsw_port *port = am65_ndev_to_port(ndev);
 	u32 ts_ctrl, seq_id, ts_ctrl_ltype2, ts_vlan_ltype;
 	struct hwtstamp_config cfg;
···
 	case HWTSTAMP_FILTER_NONE:
 		port->rx_ts_enabled = false;
 		break;
-	case HWTSTAMP_FILTER_ALL:
-	case HWTSTAMP_FILTER_SOME:
-	case HWTSTAMP_FILTER_PTP_V1_L4_EVENT:
-	case HWTSTAMP_FILTER_PTP_V1_L4_SYNC:
-	case HWTSTAMP_FILTER_PTP_V1_L4_DELAY_REQ:
 	case HWTSTAMP_FILTER_PTP_V2_L4_EVENT:
 	case HWTSTAMP_FILTER_PTP_V2_L4_SYNC:
 	case HWTSTAMP_FILTER_PTP_V2_L4_DELAY_REQ:
···
 	case HWTSTAMP_FILTER_PTP_V2_EVENT:
 	case HWTSTAMP_FILTER_PTP_V2_SYNC:
 	case HWTSTAMP_FILTER_PTP_V2_DELAY_REQ:
-	case HWTSTAMP_FILTER_NTP_ALL:
 		port->rx_ts_enabled = true;
-		cfg.rx_filter = HWTSTAMP_FILTER_ALL;
+		cfg.rx_filter = HWTSTAMP_FILTER_PTP_V2_EVENT;
 		break;
+	case HWTSTAMP_FILTER_ALL:
+	case HWTSTAMP_FILTER_SOME:
+	case HWTSTAMP_FILTER_NTP_ALL:
+		return -EOPNOTSUPP;
 	default:
 		return -ERANGE;
 	}
···
 		ts_ctrl |= AM65_CPSW_TS_TX_ANX_ALL_EN |
 			   AM65_CPSW_PN_TS_CTL_TX_VLAN_LT1_EN;
 
+	if (port->rx_ts_enabled)
+		ts_ctrl |= AM65_CPSW_TS_RX_ANX_ALL_EN |
+			   AM65_CPSW_PN_TS_CTL_RX_VLAN_LT1_EN;
+
 	writel(seq_id, port->port_base + AM65_CPSW_PORTN_REG_TS_SEQ_LTYPE_REG);
 	writel(ts_vlan_ltype, port->port_base +
 	       AM65_CPSW_PORTN_REG_TS_VLAN_LTYPE_REG);
 	writel(ts_ctrl_ltype2, port->port_base +
 	       AM65_CPSW_PORTN_REG_TS_CTL_LTYPE2);
 	writel(ts_ctrl, port->port_base + AM65_CPSW_PORTN_REG_TS_CTL);
-
-	/* en/dis RX timestamp */
-	am65_cpts_rx_enable(common->cpts, port->rx_ts_enabled);
 
 	return copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)) ? -EFAULT : 0;
 }
···
 	cfg.tx_type = port->tx_ts_enabled ?
 		      HWTSTAMP_TX_ON : HWTSTAMP_TX_OFF;
 	cfg.rx_filter = port->rx_ts_enabled ?
-			HWTSTAMP_FILTER_ALL : HWTSTAMP_FILTER_NONE;
+			HWTSTAMP_FILTER_PTP_V2_EVENT : HWTSTAMP_FILTER_NONE;
 
 	return copy_to_user(ifr->ifr_data, &cfg, sizeof(cfg)) ? -EFAULT : 0;
 }

drivers/net/ethernet/ti/am65-cpts.c

···
 	return delay;
 }
 
-/**
- * am65_cpts_rx_enable - enable rx timestamping
- * @cpts: cpts handle
- * @en: enable
- *
- * This functions enables rx packets timestamping. The CPTS can timestamp all
- * rx packets.
- */
-void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en)
-{
-	u32 val;
-
-	mutex_lock(&cpts->ptp_clk_lock);
-	val = am65_cpts_read32(cpts, control);
-	if (en)
-		val |= AM65_CPTS_CONTROL_TSTAMP_EN;
-	else
-		val &= ~AM65_CPTS_CONTROL_TSTAMP_EN;
-	am65_cpts_write32(cpts, val, control);
-	mutex_unlock(&cpts->ptp_clk_lock);
-}
-EXPORT_SYMBOL_GPL(am65_cpts_rx_enable);
-
 static int am65_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
 {
 	unsigned int ptp_class = ptp_classify_raw(skb);

drivers/net/ethernet/ti/am65-cpts.h

···
 void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
 void am65_cpts_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
 void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb);
-void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en);
 u64 am65_cpts_ns_gettime(struct am65_cpts *cpts);
 int am65_cpts_estf_enable(struct am65_cpts *cpts, int idx,
 			  struct am65_cpts_estf_cfg *cfg);
···
 
 static inline void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts,
 					       struct sk_buff *skb)
-{
-}
-
-static inline void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en)
 {
 }