gianfar: Add hardware RX timestamping support

The device is configured to insert hardware timestamps into all
received packets. The RX timestamps are extracted from the padding
alingment bytes during the clean_rx_ring operation and copied into the
skb_shared_hwtstamps struct of the skb. This extraction only happens if
the rx_filter was set to something else than HWTSTAMP_FILTER_NONE with
the SIOCSHWTSTAMP ioctl command.

Hardware timestamping is only supported for eTSEC devices. To indicate
device support the new FSL_GIANFAR_DEV_HAS_TIMER flag was introduced.
Signed-off-by: Manfred Rudigier <manfred.rudigier@omicron.at>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/gianfar.c

@@ -82,6 +82,7 @@
 #include <linux/tcp.h>
 #include <linux/udp.h>
 #include <linux/in.h>
+#include <linux/net_tstamp.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -377,6 +378,13 @@ static void gfar_init_mac(struct net_device *ndev)
 		rctrl |= RCTRL_PADDING(priv->padding);
 	}
 
+	/* Insert receive time stamps into padding alignment bytes */
+	if (priv->device_flags & FSL_GIANFAR_DEV_HAS_TIMER) {
+		rctrl &= ~RCTRL_PAL_MASK;
+		rctrl |= RCTRL_PRSDEP_INIT | RCTRL_TS_ENABLE | RCTRL_PADDING(8);
+		priv->padding = 8;
+	}
+
 	/* keep vlan related bits if it's enabled */
 	if (priv->vlgrp) {
 		rctrl |= RCTRL_VLEX | RCTRL_PRSDEP_INIT;
@@ -501,7 +509,8 @@ void unlock_tx_qs(struct gfar_private *priv)
 /* Returns 1 if incoming frames use an FCB */
 static inline int gfar_uses_fcb(struct gfar_private *priv)
 {
-	return priv->vlgrp || priv->rx_csum_enable;
+	return priv->vlgrp || priv->rx_csum_enable ||
+		(priv->device_flags & FSL_GIANFAR_DEV_HAS_TIMER);
 }
 
 static void free_tx_pointers(struct gfar_private *priv)
@@ -742,7 +751,8 @@ static int gfar_of_init(struct of_device *ofdev, struct net_device **pdev)
 			FSL_GIANFAR_DEV_HAS_CSUM |
 			FSL_GIANFAR_DEV_HAS_VLAN |
 			FSL_GIANFAR_DEV_HAS_MAGIC_PACKET |
-			FSL_GIANFAR_DEV_HAS_EXTENDED_HASH;
+			FSL_GIANFAR_DEV_HAS_EXTENDED_HASH |
+			FSL_GIANFAR_DEV_HAS_TIMER;
 
 	ctype = of_get_property(np, "phy-connection-type", NULL);
 
@@ -772,6 +782,38 @@ static int gfar_of_init(struct of_device *ofdev, struct net_device **pdev)
 	return err;
 }
 
+static int gfar_hwtstamp_ioctl(struct net_device *netdev,
+			struct ifreq *ifr, int cmd)
+{
+	struct hwtstamp_config config;
+	struct gfar_private *priv = netdev_priv(netdev);
+
+	if (copy_from_user(&config, ifr->ifr_data, sizeof(config)))
+		return -EFAULT;
+
+	/* reserved for future extensions */
+	if (config.flags)
+		return -EINVAL;
+
+	if (config.tx_type)
+		return -ERANGE;
+
+	switch (config.rx_filter) {
+	case HWTSTAMP_FILTER_NONE:
+		priv->hwts_rx_en = 0;
+		break;
+	default:
+		if (!(priv->device_flags & FSL_GIANFAR_DEV_HAS_TIMER))
+			return -ERANGE;
+		priv->hwts_rx_en = 1;
+		config.rx_filter = HWTSTAMP_FILTER_ALL;
+		break;
+	}
+
+	return copy_to_user(ifr->ifr_data, &config, sizeof(config)) ?
+		-EFAULT : 0;
+}
+
 /* Ioctl MII Interface */
 static int gfar_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 {
@@ -780,6 +822,9 @@ static int gfar_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
 	if (!netif_running(dev))
 		return -EINVAL;
 
+	if (cmd == SIOCSHWTSTAMP)
+		return gfar_hwtstamp_ioctl(dev, rq, cmd);
+
 	if (!priv->phydev)
 		return -ENODEV;
 
@@ -982,7 +1027,8 @@ static int gfar_probe(struct of_device *ofdev,
 	else
 		priv->padding = 0;
 
-	if (dev->features & NETIF_F_IP_CSUM)
+	if (dev->features & NETIF_F_IP_CSUM ||
+			priv->device_flags & FSL_GIANFAR_DEV_HAS_TIMER)
 		dev->hard_header_len += GMAC_FCB_LEN;
 
 	/* Program the isrg regs only if number of grps > 1 */
@@ -2474,6 +2520,17 @@ static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb,
 		skb_pull(skb, amount_pull);
 	}
 
+	/* Get receive timestamp from the skb */
+	if (priv->hwts_rx_en) {
+		struct skb_shared_hwtstamps *shhwtstamps = skb_hwtstamps(skb);
+		u64 *ns = (u64 *) skb->data;
+		memset(shhwtstamps, 0, sizeof(*shhwtstamps));
+		shhwtstamps->hwtstamp = ns_to_ktime(*ns);
+	}
+
+	if (priv->padding)
+		skb_pull(skb, priv->padding);
+
 	if (priv->rx_csum_enable)
 		gfar_rx_checksum(skb, fcb);
 
@@ -2510,8 +2567,7 @@ int gfar_clean_rx_ring(struct gfar_priv_rx_q *rx_queue, int rx_work_limit)
 	bdp = rx_queue->cur_rx;
 	base = rx_queue->rx_bd_base;
 
-	amount_pull = (gfar_uses_fcb(priv) ? GMAC_FCB_LEN : 0) +
-		priv->padding;
+	amount_pull = (gfar_uses_fcb(priv) ? GMAC_FCB_LEN : 0);
 
 	while (!((bdp->status & RXBD_EMPTY) || (--rx_work_limit < 0))) {
 		struct sk_buff *newskb;

drivers/net/gianfar.h

@@ -262,6 +262,7 @@ extern const char gfar_driver_version[];
 
 #define next_bd(bdp, base, ring_size) skip_bd(bdp, 1, base, ring_size)
 
+#define RCTRL_TS_ENABLE 	0x01000000
 #define RCTRL_PAL_MASK		0x001f0000
 #define RCTRL_VLEX		0x00002000
 #define RCTRL_FILREN		0x00001000
@@ -885,6 +886,7 @@ struct gfar {
 #define FSL_GIANFAR_DEV_HAS_MAGIC_PACKET	0x00000100
 #define FSL_GIANFAR_DEV_HAS_BD_STASHING		0x00000200
 #define FSL_GIANFAR_DEV_HAS_BUF_STASHING	0x00000400
+#define FSL_GIANFAR_DEV_HAS_TIMER		0x00000800
 
 #if (MAXGROUPS == 2)
 #define DEFAULT_MAPPING 	0xAA
@@ -1100,6 +1102,9 @@ struct gfar_private {
 
 	/* Network Statistics */
 	struct gfar_extra_stats extra_stats;
+
+	/* HW time stamping enabled flag */
+	int hwts_rx_en;
 };
 
 extern unsigned int ftp_rqfpr[MAX_FILER_IDX + 1];