net: ethernet: ti: am65-cpsw/cpts: Add workaround for errata i2401

The CPSW Ethernet Switch on TI's K3 SoCs supports two mechanisms to
timestamp packets received on external ports. The first mechanism which
is currently enabled by the am65-cpsw-nuss driver is that of timestamping
all received packets by setting the "TSTAMP_EN" bit in the CPTS_CONTROL
register, which directs the CPTS module to timestamp all received packets,
followed by passing the timestamps via the DMA descriptors. This mechanism
is responsible for triggering errata i2401:
"CPSW: Host Timestamps Cause CPSW Port to Lock up"

The workaround is to use the second mechanism for timestamping received
packets. The second mechanism utilizes the CPTS Event FIFO that records
timestamps corresponding to certain events, with one such event being the
reception of an Ethernet packet with the EtherType field set to Precision
Time Protocol (PTP).

Hence, switch to the second mechanism to address the errata.

The errata affects all K3 SoCs. Link to errata for AM64x:
https://www.ti.com/lit/er/sprz457h/sprz457h.pdf

Fixes: b1f66a5bee07 ("net: ethernet: ti: am65-cpsw-nuss: enable packet timestamping support")
Signed-off-by: Chintan Vankar <c-vankar@ti.com>
Reviewed-by: Ravi Gunasekaran <r-gunasekaran@ti.com>

3 files changed, 89 insertions, 55 deletions

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index cf76bade4ace..684c6e120e1c 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
@@ -92,10 +92,14 @@
 #define AM65_CPSW_PORT_REG_PRI_CTL_RX_PTYPE_RROBIN	BIT(8)
 
 /* AM65_CPSW_PN_TS_CTL register fields */
+#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_ANX_D_EN		BIT(3)
 #define AM65_CPSW_PN_TS_CTL_TX_ANX_F_EN		BIT(4)
 #define AM65_CPSW_PN_TS_CTL_TX_VLAN_LT1_EN	BIT(5)
 #define AM65_CPSW_PN_TS_CTL_TX_VLAN_LT2_EN	BIT(6)
 #define AM65_CPSW_PN_TS_CTL_TX_ANX_D_EN		BIT(7)
+#define AM65_CPSW_PN_TS_CTL_RX_ANX_E_EN		BIT(9)
 #define AM65_CPSW_PN_TS_CTL_TX_ANX_E_EN		BIT(10)
 #define AM65_CPSW_PN_TS_CTL_TX_HOST_TS_EN	BIT(11)
 #define AM65_CPSW_PN_TS_CTL_MSG_TYPE_EN_SHIFT	16
@@ -123,6 +127,11 @@
 	 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 */
 #define AM65_CPSW_MAX_TX_DESC	500
@@ -677,18 +686,6 @@ static void am65_cpsw_nuss_rx_cleanup(void *data, dma_addr_t desc_dma)
 	dev_kfree_skb_any(skb);
 }
 
-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)
@@ -769,9 +766,6 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
 	skb->dev = ndev;
 
 	psdata = cppi5_hdesc_get_psdata(desc_rx);
-	/* add RX timestamp */
-	if (port->rx_ts_enabled)
-		am65_cpsw_nuss_rx_ts(skb, psdata);
 	csum_info = psdata[2];
 	dev_dbg(dev, "%s rx csum_info:%#x\n", __func__, csum_info);
 
@@ -784,6 +778,8 @@ static int am65_cpsw_nuss_rx_packets(struct am65_cpsw_common *common,
 		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->protocol = eth_type_trans(skb, ndev);
 		am65_cpsw_nuss_rx_csum(skb, csum_info);
 		napi_gro_receive(&common->napi_rx, skb);
@@ -1312,7 +1308,6 @@ static int am65_cpsw_nuss_ndo_slave_set_mac_address(struct net_device *ndev,
 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;
@@ -1336,11 +1331,6 @@ static int am65_cpsw_nuss_hwtstamp_set(struct net_device *ndev,
 	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:
@@ -1350,10 +1340,13 @@ static int am65_cpsw_nuss_hwtstamp_set(struct net_device *ndev,
 	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;
 	}
@@ -1383,6 +1376,10 @@ static int am65_cpsw_nuss_hwtstamp_set(struct net_device *ndev,
 		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);
@@ -1390,9 +1387,6 @@ static int am65_cpsw_nuss_hwtstamp_set(struct net_device *ndev,
 	       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;
 }
 
@@ -1409,7 +1403,7 @@ static int am65_cpsw_nuss_hwtstamp_get(struct net_device *ndev,
 	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;
 }
diff --git a/drivers/net/ethernet/ti/am65-cpts.c b/drivers/net/ethernet/ti/am65-cpts.c
index c66618d91c28..29e0b9ff23bf 100644
--- a/drivers/net/ethernet/ti/am65-cpts.c
+++ b/drivers/net/ethernet/ti/am65-cpts.c
@@ -859,29 +859,6 @@ static long am65_cpts_ts_work(struct ptp_clock_info *ptp)
 	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);
@@ -906,6 +883,68 @@ static int am65_skb_get_mtype_seqid(struct sk_buff *skb, u32 *mtype_seqid)
 	return 1;
 }
 
+static u64 am65_cpts_get_rx_ts(struct am65_cpts *cpts, struct sk_buff *skb,
+			       u32 skb_mtype_seqid)
+{
+	struct list_head *this, *next;
+	struct am65_cpts_event *event;
+	unsigned long flags;
+	u32 mtype_seqid;
+	u64 ns = 0;
+
+	am65_cpts_fifo_read(cpts);
+	spin_lock_irqsave(&cpts->lock, flags);
+	list_for_each_safe(this, next, &cpts->events) {
+		event = list_entry(this, struct am65_cpts_event, list);
+		if (time_after(jiffies, event->tmo)) {
+			list_del_init(&event->list);
+			list_add(&event->list, &cpts->pool);
+			continue;
+		}
+
+		mtype_seqid = event->event1 &
+			      (AM65_CPTS_EVENT_1_MESSAGE_TYPE_MASK |
+			       AM65_CPTS_EVENT_1_SEQUENCE_ID_MASK |
+			       AM65_CPTS_EVENT_1_EVENT_TYPE_MASK);
+
+		if (mtype_seqid == skb_mtype_seqid) {
+			ns = event->timestamp;
+			list_del_init(&event->list);
+			list_add(&event->list, &cpts->pool);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&cpts->lock, flags);
+
+	return ns;
+}
+
+void am65_cpts_rx_timestamp(struct am65_cpts *cpts, struct sk_buff *skb)
+{
+	struct am65_cpts_skb_cb_data *skb_cb = (struct am65_cpts_skb_cb_data *)skb->cb;
+	struct skb_shared_hwtstamps *ssh;
+	int ret;
+	u64 ns;
+
+	skb_reset_mac_header(skb);
+	ret = am65_skb_get_mtype_seqid(skb, &skb_cb->skb_mtype_seqid);
+	if (!ret)
+		return; /* if not PTP class packet */
+
+	skb_cb->skb_mtype_seqid |= (AM65_CPTS_EV_RX << AM65_CPTS_EVENT_1_EVENT_TYPE_SHIFT);
+
+	dev_dbg(cpts->dev, "%s mtype seqid %08x\n", __func__, skb_cb->skb_mtype_seqid);
+
+	ns = am65_cpts_get_rx_ts(cpts, skb, skb_cb->skb_mtype_seqid);
+	if (!ns)
+		return;
+
+	ssh = skb_hwtstamps(skb);
+	memset(ssh, 0, sizeof(*ssh));
+	ssh->hwtstamp = ns_to_ktime(ns);
+}
+EXPORT_SYMBOL_GPL(am65_cpts_rx_timestamp);
+
 /**
  * am65_cpts_tx_timestamp - save tx packet for timestamping
  * @cpts: cpts handle
diff --git a/drivers/net/ethernet/ti/am65-cpts.h b/drivers/net/ethernet/ti/am65-cpts.h
index 6e14df0be113..6099d772799d 100644
--- a/drivers/net/ethernet/ti/am65-cpts.h
+++ b/drivers/net/ethernet/ti/am65-cpts.h
@@ -22,9 +22,9 @@ void am65_cpts_release(struct am65_cpts *cpts);
 struct am65_cpts *am65_cpts_create(struct device *dev, void __iomem *regs,
 				   struct device_node *node);
 int am65_cpts_phc_index(struct am65_cpts *cpts);
+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);
@@ -48,17 +48,18 @@ static inline int am65_cpts_phc_index(struct am65_cpts *cpts)
 	return -1;
 }
 
-static inline void am65_cpts_tx_timestamp(struct am65_cpts *cpts,
+static inline void am65_cpts_rx_timestamp(struct am65_cpts *cpts,
 					  struct sk_buff *skb)
 {
 }
 
-static inline void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts,
-					       struct sk_buff *skb)
+static inline void am65_cpts_tx_timestamp(struct am65_cpts *cpts,
+					  struct sk_buff *skb)
 {
 }
 
-static inline void am65_cpts_rx_enable(struct am65_cpts *cpts, bool en)
+static inline void am65_cpts_prep_tx_timestamp(struct am65_cpts *cpts,
+					       struct sk_buff *skb)
 {
 }