stmmac: fix PTP support for GMAC4

Due to bad management of the descriptors, when use ptp4l,
kernel panics as shown below:
-----------------------------------------------------------
 Unable to handle kernel NULL pointer dereference at virtual
 address 000001ac
 ...
 Internal error: Oops: 17 [#1] SMP ARM
 ...
 Hardware name: STi SoC with Flattened Device Tree
 task: c0c05e80 task.stack: c0c00000
 PC is at dwmac4_wrback_get_tx_timestamp_status+0x0/0xc
 LR is at stmmac_tx_clean+0x2f8/0x4d4
-----------------------------------------------------------

In case of GMAC4 the extended descriptor pointers were
used for getting the timestamp. These are NULL for this HW,
and the normal ones must be used.

The PTP also had problems on this chip due to the bad
register management and issues on the algo adopted to
setup the PTP and getting the timestamp values from the
descriptors.

Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Acked-by: Rayagond Kokatanur <rayagond@vayavyalabs.com>
Acked-by: Alexandre TORGUE <alexandre.torgue@st.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 50 insertions, 47 deletions

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index e2c94ec4edd0..1f9ec02fa7f8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -340,18 +340,17 @@ out:
 
 /* stmmac_get_tx_hwtstamp - get HW TX timestamps
  * @priv: driver private structure
- * @entry : descriptor index to be used.
+ * @p : descriptor pointer
  * @skb : the socket buffer
  * Description :
  * This function will read timestamp from the descriptor & pass it to stack.
  * and also perform some sanity checks.
  */
 static void stmmac_get_tx_hwtstamp(struct stmmac_priv *priv,
-				   unsigned int entry, struct sk_buff *skb)
+				   struct dma_desc *p, struct sk_buff *skb)
 {
 	struct skb_shared_hwtstamps shhwtstamp;
 	u64 ns;
-	void *desc = NULL;
 
 	if (!priv->hwts_tx_en)
 		return;
@@ -360,58 +359,55 @@ static void stmmac_get_tx_hwtstamp(struct stmmac_priv *priv,
 	if (likely(!skb || !(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS)))
 		return;
 
-	if (priv->adv_ts)
-		desc = (priv->dma_etx + entry);
-	else
-		desc = (priv->dma_tx + entry);
-
 	/* check tx tstamp status */
-	if (!priv->hw->desc->get_tx_timestamp_status((struct dma_desc *)desc))
-		return;
+	if (!priv->hw->desc->get_tx_timestamp_status(p)) {
+		/* get the valid tstamp */
+		ns = priv->hw->desc->get_timestamp(p, priv->adv_ts);
 
-	/* get the valid tstamp */
-	ns = priv->hw->desc->get_timestamp(desc, priv->adv_ts);
+		memset(&shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
+		shhwtstamp.hwtstamp = ns_to_ktime(ns);
 
-	memset(&shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
-	shhwtstamp.hwtstamp = ns_to_ktime(ns);
-	/* pass tstamp to stack */
-	skb_tstamp_tx(skb, &shhwtstamp);
+		netdev_info(priv->dev, "get valid TX hw timestamp %llu\n", ns);
+		/* pass tstamp to stack */
+		skb_tstamp_tx(skb, &shhwtstamp);
+	}
 
 	return;
 }
 
 /* stmmac_get_rx_hwtstamp - get HW RX timestamps
  * @priv: driver private structure
- * @entry : descriptor index to be used.
+ * @p : descriptor pointer
+ * @np : next descriptor pointer
  * @skb : the socket buffer
  * Description :
  * This function will read received packet's timestamp from the descriptor
  * and pass it to stack. It also perform some sanity checks.
  */
-static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv,
-				   unsigned int entry, struct sk_buff *skb)
+static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p,
+				   struct dma_desc *np, struct sk_buff *skb)
 {
 	struct skb_shared_hwtstamps *shhwtstamp = NULL;
 	u64 ns;
-	void *desc = NULL;
 
 	if (!priv->hwts_rx_en)
 		return;
 
-	if (priv->adv_ts)
-		desc = (priv->dma_erx + entry);
-	else
-		desc = (priv->dma_rx + entry);
-
-	/* exit if rx tstamp is not valid */
-	if (!priv->hw->desc->get_rx_timestamp_status(desc, priv->adv_ts))
-		return;
+	/* Check if timestamp is available */
+	if (!priv->hw->desc->get_rx_timestamp_status(p, priv->adv_ts)) {
+		/* For GMAC4, the valid timestamp is from CTX next desc. */
+		if (priv->plat->has_gmac4)
+			ns = priv->hw->desc->get_timestamp(np, priv->adv_ts);
+		else
+			ns = priv->hw->desc->get_timestamp(p, priv->adv_ts);
 
-	/* get valid tstamp */
-	ns = priv->hw->desc->get_timestamp(desc, priv->adv_ts);
-	shhwtstamp = skb_hwtstamps(skb);
-	memset(shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
-	shhwtstamp->hwtstamp = ns_to_ktime(ns);
+		netdev_info(priv->dev, "get valid RX hw timestamp %llu\n", ns);
+		shhwtstamp = skb_hwtstamps(skb);
+		memset(shhwtstamp, 0, sizeof(struct skb_shared_hwtstamps));
+		shhwtstamp->hwtstamp = ns_to_ktime(ns);
+	} else  {
+		netdev_err(priv->dev, "cannot get RX hw timestamp\n");
+	}
 }
 
 /**
@@ -598,17 +594,18 @@ static int stmmac_hwtstamp_ioctl(struct net_device *dev, struct ifreq *ifr)
 	priv->hwts_tx_en = config.tx_type == HWTSTAMP_TX_ON;
 
 	if (!priv->hwts_tx_en && !priv->hwts_rx_en)
-		priv->hw->ptp->config_hw_tstamping(priv->ioaddr, 0);
+		priv->hw->ptp->config_hw_tstamping(priv->ptpaddr, 0);
 	else {
 		value = (PTP_TCR_TSENA | PTP_TCR_TSCFUPDT | PTP_TCR_TSCTRLSSR |
 			 tstamp_all | ptp_v2 | ptp_over_ethernet |
 			 ptp_over_ipv6_udp | ptp_over_ipv4_udp | ts_event_en |
 			 ts_master_en | snap_type_sel);
-		priv->hw->ptp->config_hw_tstamping(priv->ioaddr, value);
+		priv->hw->ptp->config_hw_tstamping(priv->ptpaddr, value);
 
 		/* program Sub Second Increment reg */
 		sec_inc = priv->hw->ptp->config_sub_second_increment(
-			priv->ioaddr, priv->clk_ptp_rate);
+			priv->ptpaddr, priv->clk_ptp_rate,
+			priv->plat->has_gmac4);
 		temp = div_u64(1000000000ULL, sec_inc);
 
 		/* calculate default added value:
@@ -618,14 +615,14 @@ static int stmmac_hwtstamp_ioctl(struct net_device *dev, struct ifreq *ifr)
 		 */
 		temp = (u64)(temp << 32);
 		priv->default_addend = div_u64(temp, priv->clk_ptp_rate);
-		priv->hw->ptp->config_addend(priv->ioaddr,
+		priv->hw->ptp->config_addend(priv->ptpaddr,
 					     priv->default_addend);
 
 		/* initialize system time */
 		ktime_get_real_ts64(&now);
 
 		/* lower 32 bits of tv_sec are safe until y2106 */
-		priv->hw->ptp->init_systime(priv->ioaddr, (u32)now.tv_sec,
+		priv->hw->ptp->init_systime(priv->ptpaddr, (u32)now.tv_sec,
 					    now.tv_nsec);
 	}
 
@@ -1340,7 +1337,7 @@ static void stmmac_tx_clean(struct stmmac_priv *priv)
 				priv->dev->stats.tx_packets++;
 				priv->xstats.tx_pkt_n++;
 			}
-			stmmac_get_tx_hwtstamp(priv, entry, skb);
+			stmmac_get_tx_hwtstamp(priv, p, skb);
 		}
 
 		if (likely(priv->tx_skbuff_dma[entry].buf)) {
@@ -1486,10 +1483,13 @@ static void stmmac_mmc_setup(struct stmmac_priv *priv)
 	unsigned int mode = MMC_CNTRL_RESET_ON_READ | MMC_CNTRL_COUNTER_RESET |
 			    MMC_CNTRL_PRESET | MMC_CNTRL_FULL_HALF_PRESET;
 
-	if (priv->synopsys_id >= DWMAC_CORE_4_00)
+	if (priv->synopsys_id >= DWMAC_CORE_4_00) {
+		priv->ptpaddr = priv->ioaddr + PTP_GMAC4_OFFSET;
 		priv->mmcaddr = priv->ioaddr + MMC_GMAC4_OFFSET;
-	else
+	} else {
+		priv->ptpaddr = priv->ioaddr + PTP_GMAC3_X_OFFSET;
 		priv->mmcaddr = priv->ioaddr + MMC_GMAC3_X_OFFSET;
+	}
 
 	dwmac_mmc_intr_all_mask(priv->mmcaddr);
 
@@ -2484,7 +2484,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 	if (netif_msg_rx_status(priv)) {
 		void *rx_head;
 
-		pr_debug("%s: descriptor ring:\n", __func__);
+		pr_info(">>>>>> %s: descriptor ring:\n", __func__);
 		if (priv->extend_desc)
 			rx_head = (void *)priv->dma_erx;
 		else
@@ -2495,6 +2495,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 	while (count < limit) {
 		int status;
 		struct dma_desc *p;
+		struct dma_desc *np;
 
 		if (priv->extend_desc)
 			p = (struct dma_desc *)(priv->dma_erx + entry);
@@ -2514,9 +2515,11 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 		next_entry = priv->cur_rx;
 
 		if (priv->extend_desc)
-			prefetch(priv->dma_erx + next_entry);
+			np = (struct dma_desc *)(priv->dma_erx + next_entry);
 		else
-			prefetch(priv->dma_rx + next_entry);
+			np = priv->dma_rx + next_entry;
+
+		prefetch(np);
 
 		if ((priv->extend_desc) && (priv->hw->desc->rx_extended_status))
 			priv->hw->desc->rx_extended_status(&priv->dev->stats,
@@ -2568,7 +2571,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 				frame_len -= ETH_FCS_LEN;
 
 			if (netif_msg_rx_status(priv)) {
-				pr_debug("\tdesc: %p [entry %d] buff=0x%x\n",
+				pr_info("\tdesc: %p [entry %d] buff=0x%x\n",
 					p, entry, des);
 				if (frame_len > ETH_FRAME_LEN)
 					pr_debug("\tframe size %d, COE: %d\n",
@@ -2625,13 +2628,13 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit)
 						 DMA_FROM_DEVICE);
 			}
 
-			stmmac_get_rx_hwtstamp(priv, entry, skb);
-
 			if (netif_msg_pktdata(priv)) {
 				pr_debug("frame received (%dbytes)", frame_len);
 				print_pkt(skb->data, frame_len);
 			}
 
+			stmmac_get_rx_hwtstamp(priv, p, np, skb);
+
 			stmmac_rx_vlan(priv->dev, skb);
 
 			skb->protocol = eth_type_trans(skb, priv->dev);