[PATCH v3 0/3] net: Linn Ethernet Packet Sniffer driver

[PATCH v3 0/3] net: Linn Ethernet Packet Sniffer driver

[Stathis Voukelatos]

This patch adds support the Ethernet Packet Sniffer H/W module
developed by Linn Products Ltd and found in the IMG Pistachio SoC.
The module allows Ethernet packets to be parsed, matched against
a user-defined pattern and timestamped. It sits between a 100M
Ethernet MAC and PHY and is completely passive with respect to
Ethernet frames.

Matched packet bytes and timestamp values are returned through a
FIFO. Timestamps are provided to the module through an externally
generated Gray-encoded counter.

The command string for packet matching is stored in module RAM
and consists of a sequence of 16-bit entries. Each entry includes
an 8-bit command code and and 8-bit data value. Valid command
codes are:
0 - Don't care
1 - Match: packet data must match command string byte
2 - Copy: packet data will be copied to FIFO
3 - Match/Stamp: if packet data matches string byte, a timestamp
                 is copied into the FIFO
4 - Copy/Done: packet data will be copied into the FIFO.
               This command terminates the command string.

The driver consists of two modules:
- Core: it provides a common framework for managing backend packet
        sniffer implementations. Each backend channel is registered
        by the core as a netdev, which can be accessed from user
        space through a raw packet socket. 

- Ethernet Packet Sniffer backend: provides the driver for the
        Linn Ethernet Packet Sniffer H/W modules.

The split between a core and backend modules allows for other
implementations to be added in the future apart of the Ethernet
packet sniffer presented in this patch set.

Changes for v3:
* Code moved into vendor specific directory
* Device tree binding updated and streamlined. Cyclecounter params
  are now calculated dynamically.

Changes for v2:
* Complete redesign of core framework to use netdev instead of 
the generic netlink framework
* Updated device tree binding
* A number of minor code improvements suggested by code review

Stathis Voukelatos (3):
  Ethernet packet sniffer: device tree binding and vendor prefix
  Packet sniffer core framework
  Linn Ethernet packet sniffer driver

 .../bindings/net/linn-ether-packet-sniffer.txt     |  39 ++
 .../devicetree/bindings/vendor-prefixes.txt        |   1 +
 MAINTAINERS                                        |   6 +
 drivers/net/ethernet/Kconfig                       |   1 +
 drivers/net/ethernet/Makefile                      |   1 +
 drivers/net/ethernet/linn/Kconfig                  |  36 ++
 drivers/net/ethernet/linn/Makefile                 |  20 +
 .../linn/pkt-sniffer/backends/ether/Makefile       |  20 +
 .../linn/pkt-sniffer/backends/ether/channel.c      | 455 +++++++++++++++++++++
 .../linn/pkt-sniffer/backends/ether/channel.h      |  80 ++++
 .../ethernet/linn/pkt-sniffer/backends/ether/hw.h  |  46 +++
 .../linn/pkt-sniffer/backends/ether/platform.c     | 286 +++++++++++++
 .../net/ethernet/linn/pkt-sniffer/core/Makefile    |  20 +
 .../net/ethernet/linn/pkt-sniffer/core/module.c    |  37 ++
 .../net/ethernet/linn/pkt-sniffer/core/netdev.c    | 254 ++++++++++++
 .../net/ethernet/linn/pkt-sniffer/core/snf_core.h  |  60 +++
 16 files changed, 1362 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt
 create mode 100644 drivers/net/ethernet/linn/Kconfig
 create mode 100644 drivers/net/ethernet/linn/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.h
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/hw.h
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/platform.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/module.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/netdev.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/snf_core.h

-- 
1.9.1

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[PATCH v3 1/3] Ethernet packet sniffer: device tree binding and vendor prefix

[Stathis Voukelatos]

Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
---
 .../bindings/net/linn-ether-packet-sniffer.txt     | 39 ++++++++++++++++++++++
 .../devicetree/bindings/vendor-prefixes.txt        |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt

diff --git a/Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt b/Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt
new file mode 100644
index 0000000..66bfc48
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt
@@ -0,0 +1,39 @@
+* Linn Products Ethernet Packet Sniffer
+The module allows Ethernet packets to be parsed, matched against
+a user-defined pattern and timestamped. It sits between a 100M
+Ethernet MAC and PHY and is completely passive with respect to
+Ethernet frames.
+Matched packet bytes and timestamp values are returned through a
+FIFO. Timestamps are provided to the module through an externally
+generated Gray-encoded counter.
+
+Required properties:
+- compatible : must be "linn,eth-packet-sniffer"
+- reg : a list of physical address and size pairs corresponding to
+	each entry in 'reg-names'
+- reg-names : must contain:
+		"regs"   : control registers
+		"tx-ram" : TX command string memory
+		"rx-ram" : RX command string memory
+- interrupts : sniffer interrupt specifier
+- clocks : list of clocks corresponding to each entry in 'clock-names'
+- clock-names : must contain:
+		"sys"    : system clock for the peripheral
+		"tstamp" : timestamp counter clock
+- fifo-block-words : number of words in one data FIFO entry
+- tstamp-bits : width in bits of the timestamp counter
+
+Example:
+
+sniffer@1814a000 {
+	compatible = "linn,eth-sniffer";
+	reg = <0x1814a000 0x100>, <0x1814a400 0x400>,
+	      <0x1814a800 0x400>;
+	reg-names = "regs", "tx-ram", "rx-ram";
+	interrupts = <GIC_SHARED 58 IRQ_TYPE_LEVEL_HIGH>;
+	clocks = <&cr_periph SYS_CLK_ENET>,
+		 <&clk_core CLK_AUDIO>;
+	clock-names = "sys", "tstamp";
+	fifo-block-words = <4>;
+	tstamp-bits = <30>;
+};
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.txt b/Documentation/devicetree/bindings/vendor-prefixes.txt
index 389ca13..f685707 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.txt
+++ b/Documentation/devicetree/bindings/vendor-prefixes.txt
@@ -102,6 +102,7 @@ lacie	LaCie
 lantiq	Lantiq Semiconductor
 lenovo	Lenovo Group Ltd.
 lg	LG Corporation
+linn	Linn Products Ltd.
 linux	Linux-specific binding
 lsi	LSI Corp. (LSI Logic)
 lltc	Linear Technology Corporation
-- 
1.9.1

[PATCH v3 2/3] Packet sniffer core framework

[Stathis Voukelatos]

The framework registers each backend sniffer channel as a netdev,
which can be accessed from user space through a raw packet socket.
Packets received from user space are treated as a command string
configuration. Each match event from the backend driver will
generate a packet with the matching bytes plus an optional
timestamp, if configured by the command string.

Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
---
 MAINTAINERS                                        |   6 +
 drivers/net/ethernet/Kconfig                       |   1 +
 drivers/net/ethernet/Makefile                      |   1 +
 drivers/net/ethernet/linn/Kconfig                  |  25 ++
 drivers/net/ethernet/linn/Makefile                 |  19 ++
 .../net/ethernet/linn/pkt-sniffer/core/Makefile    |  20 ++
 .../net/ethernet/linn/pkt-sniffer/core/module.c    |  37 +++
 .../net/ethernet/linn/pkt-sniffer/core/netdev.c    | 254 +++++++++++++++++++++
 .../net/ethernet/linn/pkt-sniffer/core/snf_core.h  |  60 +++++
 9 files changed, 423 insertions(+)
 create mode 100644 drivers/net/ethernet/linn/Kconfig
 create mode 100644 drivers/net/ethernet/linn/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/module.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/netdev.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/core/snf_core.h

diff --git a/MAINTAINERS b/MAINTAINERS
index ddc5a8c..716b10c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -5835,6 +5835,12 @@ M:	Sasha Levin <sasha.levin@oracle.com>
 S:	Maintained
 F:	tools/lib/lockdep/
 
+LINN PACKET SNIFFER DRIVER
+M: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+S: Maintained
+F: drivers/net/ethernet/linn/
+F: Documentation/devicetree/bindings/net/linn-ether-packet-sniffer.txt
+
 LINUX FOR IBM pSERIES (RS/6000)
 M:	Paul Mackerras <paulus@au.ibm.com>
 W:	http://www.ibm.com/linux/ltc/projects/ppc
diff --git a/drivers/net/ethernet/Kconfig b/drivers/net/ethernet/Kconfig
index eadcb05..ee4b3ed 100644
--- a/drivers/net/ethernet/Kconfig
+++ b/drivers/net/ethernet/Kconfig
@@ -103,6 +103,7 @@ config LANTIQ_ETOP
 	---help---
 	  Support for the MII0 inside the Lantiq SoC
 
+source "drivers/net/ethernet/linn/Kconfig"
 source "drivers/net/ethernet/marvell/Kconfig"
 source "drivers/net/ethernet/mellanox/Kconfig"
 source "drivers/net/ethernet/micrel/Kconfig"
diff --git a/drivers/net/ethernet/Makefile b/drivers/net/ethernet/Makefile
index 1367afc..f8071d3 100644
--- a/drivers/net/ethernet/Makefile
+++ b/drivers/net/ethernet/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_NET_VENDOR_HP) += hp/
 obj-$(CONFIG_NET_VENDOR_IBM) += ibm/
 obj-$(CONFIG_NET_VENDOR_INTEL) += intel/
 obj-$(CONFIG_NET_VENDOR_I825XX) += i825xx/
+obj-$(CONFIG_NET_VENDOR_LINN) += linn/
 obj-$(CONFIG_NET_VENDOR_XSCALE) += xscale/
 obj-$(CONFIG_IP1000) += icplus/
 obj-$(CONFIG_JME) += jme.o
diff --git a/drivers/net/ethernet/linn/Kconfig b/drivers/net/ethernet/linn/Kconfig
new file mode 100644
index 0000000..6654f4e
--- /dev/null
+++ b/drivers/net/ethernet/linn/Kconfig
@@ -0,0 +1,25 @@
+#
+# Linn device configuration
+#
+
+config NET_VENDOR_LINN
+	bool "Linn devices"
+	---help---
+	  Say Y to add support for Linn Products devices.
+
+	  Note that the answer to this question doesn't directly affect the
+	  kernel: saying N will just cause the configurator to skip all
+	  the questions about Linn devices. If you say Y, you will be asked for
+	  your specific device in the following questions.
+
+if NET_VENDOR_LINN
+
+menuconfig PKT_SNIFFER
+    tristate "Packet sniffer support"
+    ---help---
+    Say Y to add support for the packet sniffer driver framework.
+
+    The core driver can also be built as a module. If so, the module
+    will be called snf_core.
+
+endif # NET_VENDOR_LINN
diff --git a/drivers/net/ethernet/linn/Makefile b/drivers/net/ethernet/linn/Makefile
new file mode 100644
index 0000000..f3338f3
--- /dev/null
+++ b/drivers/net/ethernet/linn/Makefile
@@ -0,0 +1,19 @@
+###############################################################################
+# Makefile for the Linn Products device drivers
+#
+# Copyright (C) 2015 Linn Products Ltd
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2
+# as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# Written by:
+# Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+###############################################################################
+
+obj-$(CONFIG_PKT_SNIFFER) += pkt-sniffer/core/
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/core/Makefile b/drivers/net/ethernet/linn/pkt-sniffer/core/Makefile
new file mode 100644
index 0000000..137db75
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/core/Makefile
@@ -0,0 +1,20 @@
+###############################################################################
+# Makefile for the Linn packet sniffer framework driver
+#
+# Copyright (C) 2015 Linn Products Ltd
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2
+# as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# Written by:
+# Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+###############################################################################
+
+obj-$(CONFIG_PKT_SNIFFER) += snf_core.o
+snf_core-objs := netdev.o module.o
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/core/module.c b/drivers/net/ethernet/linn/pkt-sniffer/core/module.c
new file mode 100644
index 0000000..1dbed1f
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/core/module.c
@@ -0,0 +1,37 @@
+/*
+ * Packet sniffer core driver:
+ *  - backend channel management
+ *  - interface to userland as a network I/F
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+
+static int __init snf_core_init(void)
+{
+	return 0;
+}
+
+static void __exit snf_core_cleanup(void)
+{
+}
+
+module_init(snf_core_init);
+module_exit(snf_core_cleanup);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Core packet sniffer driver");
+MODULE_AUTHOR("Linn Products Ltd");
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/core/netdev.c b/drivers/net/ethernet/linn/pkt-sniffer/core/netdev.c
new file mode 100644
index 0000000..ba25cc0
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/core/netdev.c
@@ -0,0 +1,254 @@
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/net_tstamp.h>
+#include <linux/if_arp.h>
+#include <linux/spinlock.h>
+#include "snf_core.h"
+
+struct snf_ndev_state {
+	struct snf_chan *chan;
+	bool rx_tstamp_enabled;
+	spinlock_t lock;
+};
+
+static int hw_timestamp_set(struct net_device *dev, struct ifreq *ifr)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+	struct hwtstamp_config tconf;
+
+	if (copy_from_user(&tconf, ifr->ifr_data, sizeof(tconf)))
+		return -EFAULT;
+
+	/* No TX timestamping supported.
+	 * This interface only receives packets from the sniffer backend
+	 */
+	if (tconf.tx_type != HWTSTAMP_TX_OFF)
+		return -ERANGE;
+
+	if (tconf.rx_filter != HWTSTAMP_FILTER_NONE) {
+		/* If timestamping is not enabled in the command string then
+		 * we cannot return any RX timestamps
+		 */
+		if (!priv->chan->ts_enabled(priv->chan))
+			return -ERANGE;
+		priv->rx_tstamp_enabled = true;
+		tconf.rx_filter = HWTSTAMP_FILTER_ALL;
+	} else {
+		priv->rx_tstamp_enabled = false;
+	}
+
+	return copy_to_user(ifr->ifr_data, &tconf, sizeof(tconf)) ? -EFAULT : 0;
+}
+
+static int hw_timestamp_get(struct net_device *dev, struct ifreq *ifr)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+	struct hwtstamp_config tconf;
+
+	memset(&tconf, 0, sizeof(tconf));
+	tconf.tx_type = HWTSTAMP_TX_OFF;
+	/* We also need to check here that the current command string
+	 * will cause timestamps to be generated
+	 */
+	tconf.rx_filter = (priv->rx_tstamp_enabled &&
+			   priv->chan->ts_enabled(priv->chan)) ?
+			   HWTSTAMP_FILTER_ALL : HWTSTAMP_FILTER_NONE;
+
+	return copy_to_user(ifr->ifr_data, &tconf, sizeof(tconf)) ? -EFAULT : 0;
+}
+
+static int snf_init(struct net_device *dev)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+
+	/* Two bytes per command string entry */
+	dev->mtu = priv->chan->max_ptn_entries(priv->chan) * 2;
+	return 0;
+}
+
+static int snf_open(struct net_device *dev)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = priv->chan->start(priv->chan);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return ret;
+}
+
+static int snf_stop(struct net_device *dev)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = priv->chan->stop(priv->chan);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return ret;
+}
+
+static int snf_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
+{
+	switch (cmd) {
+	case SIOCSHWTSTAMP:
+		return hw_timestamp_set(dev, ifr);
+
+	case SIOCGHWTSTAMP:
+		return hw_timestamp_get(dev, ifr);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static int snf_start_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct snf_ndev_state *priv = netdev_priv(dev);
+	struct snf_chan *sch = priv->chan;
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	/* Stop the hardware */
+	sch->stop(sch);
+	/* Set the new command pattern */
+	ret = sch->set_pattern(sch, skb->data, skb->len / 2);
+	/* Restart the hardware */
+	sch->start(sch);
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	if (ret < 0) {
+		dev->stats.tx_dropped++;
+	} else {
+		dev->stats.tx_packets++;
+		dev->stats.tx_bytes += skb->len;
+	}
+
+	dev_kfree_skb(skb);
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops snf_netdev_ops = {
+	.ndo_init       = snf_init,
+	.ndo_open       = snf_open,
+	.ndo_stop       = snf_stop,
+	.ndo_start_xmit	= snf_start_xmit,
+	.ndo_do_ioctl   = snf_ioctl
+};
+
+static void snf_setup(struct net_device *dev)
+{
+	dev->netdev_ops   = &snf_netdev_ops;
+	dev->tx_queue_len = 1;
+	dev->flags        = IFF_NOARP;
+	dev->type         = ARPHRD_NONE;
+}
+
+/* Initialise netdev for a sniffer channel */
+int snf_channel_add(struct snf_chan *sch, const char *name)
+{
+	int ret;
+	struct net_device *ndev;
+	struct snf_ndev_state *priv;
+
+	ndev = alloc_netdev(sizeof(*priv), name, NET_NAME_UNKNOWN, snf_setup);
+	if (!ndev)
+		return -ENOMEM;
+
+	priv = netdev_priv(ndev);
+	priv->chan = sch;
+	priv->rx_tstamp_enabled = false;
+	spin_lock_init(&priv->lock);
+
+	ret = register_netdev(ndev);
+	if (ret < 0) {
+		free_netdev(ndev);
+		return ret;
+	}
+
+	sch->cstate = ndev;
+	return 0;
+}
+EXPORT_SYMBOL(snf_channel_add);
+
+/* Release netdev for a sniffer channel and free resources */
+int snf_channel_remove(struct snf_chan *sch)
+{
+	struct net_device *ndev = (struct net_device *)sch->cstate;
+
+	unregister_netdev(ndev);
+	free_netdev(ndev);
+	return 0;
+}
+EXPORT_SYMBOL(snf_channel_remove);
+
+/* Send a packet to user space for a sniffer match event */
+int snf_channel_notify_match(struct snf_chan *sch, struct snf_match_evt *mt)
+{
+	struct net_device *ndev = (struct net_device *)sch->cstate;
+	struct snf_ndev_state *priv = netdev_priv(ndev);
+	struct sk_buff *skb;
+	struct skb_shared_hwtstamps *skts;
+
+	skb = netdev_alloc_skb(ndev, mt->len);
+	if (!skb) {
+		ndev->stats.rx_dropped++;
+		return -ENOMEM;
+	}
+
+	skb_put(skb, mt->len);
+	skb_copy_to_linear_data(skb, mt->data, mt->len);
+	if (mt->ts_valid && priv->rx_tstamp_enabled) {
+		skts = skb_hwtstamps(skb);
+		skts->hwtstamp = ns_to_ktime(mt->ts);
+	}
+	ndev->stats.rx_packets++;
+	ndev->stats.rx_bytes += mt->len;
+	netif_rx(skb);
+	return 0;
+}
+EXPORT_SYMBOL(snf_channel_notify_match);
+
+/* Suspend the interface */
+int snf_channel_suspend(struct snf_chan *sch)
+{
+	struct net_device *ndev = (struct net_device *)sch->cstate;
+	struct snf_ndev_state *priv = netdev_priv(ndev);
+	unsigned long flags;
+	int ret;
+
+	if (!netif_running(ndev))
+		return 0;
+
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = sch->stop(sch);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	netif_device_detach(ndev);
+	return ret;
+}
+EXPORT_SYMBOL(snf_channel_suspend);
+
+/* Resume the interface */
+int snf_channel_resume(struct snf_chan *sch)
+{
+	struct net_device *ndev = (struct net_device *)sch->cstate;
+	struct snf_ndev_state *priv = netdev_priv(ndev);
+	unsigned long flags;
+	int ret;
+
+	if (!netif_running(ndev))
+		return 0;
+
+	netif_device_attach(ndev);
+	spin_lock_irqsave(&priv->lock, flags);
+	ret = sch->start(sch);
+	spin_unlock_irqrestore(&priv->lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(snf_channel_resume);
+
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/core/snf_core.h b/drivers/net/ethernet/linn/pkt-sniffer/core/snf_core.h
new file mode 100644
index 0000000..73a30ff
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/core/snf_core.h
@@ -0,0 +1,60 @@
+/*
+ * Packet sniffer core driver
+ * - this header provides the interface to specific backend packet
+ *   sniffer implementations
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#ifndef __SNF_CORE_H
+#define __SNF_CORE_H
+
+#include <linux/types.h>
+
+/* This is a global maximum. Each backend will have its own limit */
+#define MAX_MATCH_BYTES 512
+
+/* Sniffer channel data structure */
+struct snf_chan {
+	int  (*start)(struct snf_chan *sch);
+	int  (*stop)(struct snf_chan *sch);
+	int  (*set_pattern)(struct snf_chan *sch, const u8 *pattern, int count);
+	int  (*max_ptn_entries)(struct snf_chan *sch);
+	int  (*ts_enabled)(struct snf_chan *sch);
+	void *cstate;
+};
+
+/* Data from a sniffer match event */
+struct snf_match_evt {
+	int ts_valid;     /* flag indicating if timestamp is present */
+	u64 ts;           /* timestamp value */
+	u8 data[MAX_MATCH_BYTES]; /* packet data bytes matched by sniffer */
+	int len;          /* number of valid bytes in the 'data' buffer */
+};
+
+/* Registers a sniffer channel */
+int snf_channel_add(struct snf_chan *sch, const char *name);
+
+/* Removes a sniffer channel */
+int snf_channel_remove(struct snf_chan *sch);
+
+/* Send a packet to user space for a sniffer match event */
+int snf_channel_notify_match(struct snf_chan *sch, struct snf_match_evt *mt);
+
+/* Suspend and resume operations */
+int snf_channel_suspend(struct snf_chan *sch);
+int snf_channel_resume(struct snf_chan *sch);
+
+#endif
+
-- 
1.9.1

[PATCH v3 3/3] Linn Ethernet packet sniffer driver

[Stathis Voukelatos]

Driver for the Ethernet Mii packet sniffer H/W module found in
the IMG Pistachio SoC.

Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
---
 drivers/net/ethernet/linn/Kconfig                  |  11 +
 drivers/net/ethernet/linn/Makefile                 |   1 +
 .../linn/pkt-sniffer/backends/ether/Makefile       |  20 +
 .../linn/pkt-sniffer/backends/ether/channel.c      | 455 +++++++++++++++++++++
 .../linn/pkt-sniffer/backends/ether/channel.h      |  80 ++++
 .../ethernet/linn/pkt-sniffer/backends/ether/hw.h  |  46 +++
 .../linn/pkt-sniffer/backends/ether/platform.c     | 286 +++++++++++++
 7 files changed, 899 insertions(+)
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/Makefile
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.c
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.h
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/hw.h
 create mode 100644 drivers/net/ethernet/linn/pkt-sniffer/backends/ether/platform.c

diff --git a/drivers/net/ethernet/linn/Kconfig b/drivers/net/ethernet/linn/Kconfig
index 6654f4e..bbfd6a4 100644
--- a/drivers/net/ethernet/linn/Kconfig
+++ b/drivers/net/ethernet/linn/Kconfig
@@ -22,4 +22,15 @@ menuconfig PKT_SNIFFER
     The core driver can also be built as a module. If so, the module
     will be called snf_core.
 
+config PKT_SNIFFER_ETHER
+    tristate "Ethernet packet sniffer"
+    depends on PKT_SNIFFER
+    help
+        Say Y here if you want to use the Ethernet packet sniffer
+        module by Linn Products Ltd. It can be found in the upcoming
+        Pistachio SoC by Imagination Technologies.
+
+        The driver can also be built as a module. If so, the module
+        will be called snf_ether.
+
 endif # NET_VENDOR_LINN
diff --git a/drivers/net/ethernet/linn/Makefile b/drivers/net/ethernet/linn/Makefile
index f3338f3..f51eb66 100644
--- a/drivers/net/ethernet/linn/Makefile
+++ b/drivers/net/ethernet/linn/Makefile
@@ -17,3 +17,4 @@
 ###############################################################################
 
 obj-$(CONFIG_PKT_SNIFFER) += pkt-sniffer/core/
+obj-$(CONFIG_PKT_SNIFFER_ETHER) += pkt-sniffer/backends/ether/
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/Makefile b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/Makefile
new file mode 100644
index 0000000..1f97e51
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/Makefile
@@ -0,0 +1,20 @@
+###############################################################################
+# Makefile for the Linn ethernet packet sniffer driver
+#
+# Copyright (C) 2015 Linn Products Ltd
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2
+# as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# Written by:
+# Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+###############################################################################
+
+obj-$(CONFIG_PKT_SNIFFER_ETHER) += snf_ether.o
+snf_ether-objs := platform.o channel.o
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.c b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.c
new file mode 100644
index 0000000..2b502e8
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.c
@@ -0,0 +1,455 @@
+/*
+ * Ethernet Mii packet sniffer driver
+ *  - channel functions
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#include <linux/io.h>
+#include <linux/hrtimer.h>
+#include <linux/clocksource.h>
+#include "../../core/snf_core.h"
+#include "hw.h"
+#include "channel.h"
+
+#define to_ether_snf_chan(dev) container_of(dev, struct ether_snf_chan, chan)
+
+/* Checks if the supplied command string is compatible with the
+ * capabilities of the H/W. The command string consists of a series
+ * of bytes in the following format
+ *  --------------------------------
+ *  | CMD | DATA | CMD | DATA | ....
+ *  --------------------------------
+ * Valid command IDs are the following:
+ * 0 - Don't care
+ * 1 - Match: packet data must match command string byte
+ * 2 - Copy: packet data will be copied to FIFO
+ * 3 - Match/Stamp: if packet data matches string byte, a timestamp
+ *                  is copied into the FIFO
+ * 4 - Copy/Done: packet data will be copied into the FIFO.
+ *                This command terminates the command string.
+ */
+#define CMD_DONTCARE	0
+#define CMD_MATCH	1
+#define CMD_COPY	2
+#define CMD_MATCHSTAMP	3
+#define CMD_COPYDONE	4
+static bool validate_pattern(
+			struct ether_snf_chan *ch,
+			const u8 *buf,
+			int count)
+{
+	int i, complete, max_copy_bytes;
+	int ts = 0;
+	int copy_before = 0;
+	int copy_after = 0;
+
+	if (count > ch->max_cmds)
+		return false;
+
+	/* Iterate through the commands in the string */
+	for (i = 0, complete = 0; (i < count) && !complete; i++) {
+		u8 cmd = buf[2 * i];
+
+		switch (cmd) {
+		case CMD_DONTCARE:
+		case CMD_MATCH:
+			break;
+
+		case CMD_MATCHSTAMP:
+			/* The timestamp needs to be word-aligned in the FIFO
+			 * therefore, the number of 'copy' commands before it
+			 * needs to be a multiple of 4
+			 */
+			if (copy_before & 3)
+				return false;
+			/* Signal that a timestamp will be present */
+			ts = 1;
+			break;
+
+		case CMD_COPY:
+			/* Increment count of bytes that will be returned */
+			if (ts)
+				copy_after++;
+			else
+				copy_before++;
+			break;
+
+		case CMD_COPYDONE:
+			/* Increment count of bytes that will be returned
+			 * This command terminates the string
+			 */
+			if (ts)
+				copy_after++;
+			else
+				copy_before++;
+			/* This command completes the command string */
+			complete = 1;
+			break;
+
+		default:
+			/* Invalid command id */
+			return false;
+		}
+	}
+
+	/* Check if the string was properly terminated
+	 * and contained valid number of commands
+	 */
+	if (complete) {
+		max_copy_bytes = ch->fifo_blk_words * 4;
+		if (ts)
+			max_copy_bytes -= 4;
+		/* Too many copy commands will case the FIFO
+		 * to wrap around
+		 */
+		if ((copy_before + copy_after) > max_copy_bytes)
+			return false;
+		ch->nfb_before = copy_before;
+		ch->nfb_after = copy_after;
+		ch->evt.ts_valid = ts;
+		ch->evt.len = ch->nfb_before + ch->nfb_after;
+		return true;
+	}
+
+	/* Command string not terminated */
+	return false;
+}
+
+/* Channel methods */
+
+/* Enables the channel */
+static int esnf_start(struct snf_chan *dev)
+{
+	struct ether_snf_chan *ch = to_ether_snf_chan(dev);
+
+	if (!ch->started) {
+		ch->evt.ts = 0;
+		/* Enable interrupts */
+		iowrite32(ch->data_irq_bit | ch->full_irq_bit,
+			  ch->regs + SET_INTERRUPT_ENABLE);
+		/* Enable the packet matching logic */
+		iowrite32(ENABLE_BIT, ch->reg_enable);
+
+		ch->started = 1;
+		dev_info(ch->dev, "%s: started\n", ch->name);
+	} else {
+		dev_dbg(ch->dev, "%s: already running\n", ch->name);
+	}
+
+	return 0;
+}
+
+/* Disables the channel */
+static int esnf_stop(struct snf_chan *dev)
+{
+	struct ether_snf_chan *ch = to_ether_snf_chan(dev);
+
+	if (ch->started) {
+		/* Disable interrupts */
+		iowrite32(ch->data_irq_bit | ch->full_irq_bit,
+			  ch->regs + CLEAR_INTERRUPT_ENABLE);
+		/* Stop the sniffer channel */
+		iowrite32(0, ch->reg_enable);
+		/* Clear any pending interrupts */
+		iowrite32(ch->data_irq_bit | ch->full_irq_bit,
+			  ch->regs + INTERRUPT_STATUS);
+
+		ch->started = 0;
+		dev_info(ch->dev, "%s: stopped\n", ch->name);
+	} else {
+		dev_dbg(ch->dev, "%s: already stopped\n", ch->name);
+	}
+
+	return 0;
+}
+
+/* Sets the command string (pattern) for the channel
+ * The bytes in the pattern buffer are in the following order:
+ */
+static int esnf_set_pattern(struct snf_chan *dev, const u8 *pattern, int count)
+{
+	struct ether_snf_chan *ch = to_ether_snf_chan(dev);
+	int i, shift = 0;
+	u32  val = 0, *ptr;
+
+	dev_info(ch->dev, "%s: set cmd pattern with %d entries\n",
+		 ch->name, count);
+
+	if (ch->started) {
+		dev_err(ch->dev,
+			"%s: cannot apply cmd pattern. Channel is active\n",
+			ch->name);
+		return -EBUSY;
+	}
+
+	if (!validate_pattern(ch, pattern, count)) {
+		dev_err(ch->dev,
+			"%s: invalid cmd pattern\n",
+			ch->name);
+		return -EINVAL;
+	}
+
+	for (ptr = ch->cmd_ram, i = 0, shift = 24; i < (2 * count); i++) {
+		val |= ((u32)pattern[i]) << shift;
+		if (!shift) {
+			iowrite32(val, ptr++);
+			val = 0;
+			shift = 24;
+		} else {
+			shift -= 8;
+		}
+	}
+	if (shift)
+		iowrite32(val, ptr);
+
+	return 0;
+}
+
+/* Returns max number of commands supported by the channel */
+static int esnf_max_ptn_entries(struct snf_chan *dev)
+{
+	struct ether_snf_chan *ch = to_ether_snf_chan(dev);
+
+	return ch->max_cmds;
+}
+
+static int esnf_ts_enabled(struct snf_chan *dev)
+{
+	struct ether_snf_chan *ch = to_ether_snf_chan(dev);
+
+	return ch->evt.ts_valid;
+}
+
+/* Gray decoder */
+static u32 gray_decode(u32 gray)
+{
+	gray ^= (gray >> 16);
+	gray ^= (gray >> 8);
+	gray ^= (gray >> 4);
+	gray ^= (gray >> 2);
+	gray ^= (gray >> 1);
+	return gray;
+}
+
+/* Read a block from the data FIFO */
+static void read_fifo_data(struct ether_snf_chan *ch)
+{
+	int i;
+	u32 val, *ptr;
+	int ts = ch->evt.ts_valid;
+	int dw = ch->fifo_blk_words;
+	int bytes_before = ch->nfb_before;
+	int bytes_after = ch->nfb_after;
+
+	ptr = (u32 *)ch->evt.data;
+	for (i = 0; i < dw; i++) {
+		val = ioread32(ch->reg_fifo);
+		if (bytes_before > 0) {
+			/* Bytes before the timestamp */
+			*ptr++ = cpu_to_be32(val);
+			bytes_before -= 4;
+		} else if (ts) {
+			ch->raw_tstamp = gray_decode(val);
+			/* First timestamp since the channel was started.
+			 * Initialise the timecounter
+			 */
+			if (!ch->evt.ts)
+				timecounter_init(
+					&ch->tc,
+					&ch->cc,
+					ktime_to_ns(ktime_get_real()));
+			ch->evt.ts = timecounter_read(&ch->tc);
+			ts = 0;
+		} else if (bytes_after > 0) {
+			/* Bytes after the timestamp */
+			*ptr++ = cpu_to_be32(val);
+			bytes_after -= 4;
+		}
+	}
+}
+
+/* Read method for the timestamp cycle counter
+ * Returns the last received timestamp value
+ */
+static cycle_t esnf_cyclecounter_read(const struct cyclecounter *cc)
+{
+	struct ether_snf_chan *ch = container_of(cc, struct ether_snf_chan, cc);
+
+	return ch->raw_tstamp;
+}
+
+/* Taken from clocks_calc_mult_shift() in kernel/time/clocksource.c
+ * Unfortunately that function is not exported by the kernel
+ */
+static void esnf_clocks_calc_mult_shift(
+				u32 *mult,
+				u32 *shift,
+				u32 from,
+				u32 to,
+				u32 maxsec)
+{
+	u64 tmp;
+	u32 sft, sftacc = 32;
+
+	/* Calculate the shift factor which is limiting the conversion
+	 * range:
+	 */
+	tmp = ((u64)maxsec * from) >> 32;
+	while (tmp) {
+		tmp >>= 1;
+		sftacc--;
+	}
+
+	/* Find the conversion shift/mult pair which has the best
+	 * accuracy and fits the maxsec conversion range:
+	 */
+	for (sft = 32; sft > 0; sft--) {
+		tmp = (u64)to << sft;
+		tmp += from / 2;
+		do_div(tmp, from);
+		if ((tmp >> sftacc) == 0)
+			break;
+	}
+	*mult = tmp;
+	*shift = sft;
+}
+
+/* Follows the logic of __clocksource_updatefreq_scale() in
+ * in kernel/time/clocksource.c
+ */
+static void calc_mult_shift(u32 *mult, u32 *shift, cycle_t mask, u32 freq)
+{
+	u64 sec;
+
+	sec = mask - (mask >> 3);
+	do_div(sec, freq);
+	if (!sec)
+		sec = 1;
+	else if (sec > 600 && mask > UINT_MAX)
+		sec = 600;
+	esnf_clocks_calc_mult_shift(mult, shift, freq, NSEC_PER_SEC, sec);
+}
+
+/* Initialises a sniffer channel */
+int channel_init(
+	struct ether_snf_chan *ch,
+	struct platform_device *pdev,
+	void *regs,
+	int fifo_blk_words,
+	u32 tstamp_hz,
+	u32 tstamp_bits,
+	int tx)
+{
+	struct resource *res;
+	u32 *ptr;
+	int i;
+
+	ch->regs = regs;
+	ch->dev = &pdev->dev;
+	ch->data_irq_bit = tx ? TX_DATA_IRQ_BIT : RX_DATA_IRQ_BIT;
+	ch->full_irq_bit = tx ? TX_FULL_IRQ_BIT : RX_FULL_IRQ_BIT;
+	ch->reg_enable = ch->regs +
+			 (tx ? TX_SNIFFER_ENABLE : RX_SNIFFER_ENABLE);
+	ch->reg_fifo = ch->regs + (tx ? TX_FIFO_DAT : RX_FIFO_DAT);
+
+	/* Retrieve and remap the address space for the command memory */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
+					   tx ? "tx-ram" : "rx-ram");
+	if (!res)
+		return -ENOSYS;
+	ch->cmd_ram = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(ch->cmd_ram))
+		return PTR_ERR(ch->cmd_ram);
+
+	/* It is 2 bytes/command, hence divide by 2 */
+	ch->max_cmds = resource_size(res) / 2;
+
+	/* Initialise the command string RAM */
+	for (i = 0, ptr = ch->cmd_ram; i < resource_size(res); i += 4)
+		iowrite32((CMD_DONTCARE << 24) | (CMD_DONTCARE << 8),
+			  ptr++);
+
+	ch->fifo_blk_words = fifo_blk_words;
+	ch->started = 0;
+
+	/* Initialise the timestamp cycle counter */
+	ch->cc.read = esnf_cyclecounter_read;
+	ch->cc.mask = CLOCKSOURCE_MASK(tstamp_bits);
+	calc_mult_shift(&ch->cc.mult, &ch->cc.shift, ch->cc.mask, tstamp_hz);
+
+	/* Register the channel methods */
+	ch->chan.start = esnf_start;
+	ch->chan.stop = esnf_stop;
+	ch->chan.set_pattern = esnf_set_pattern;
+	ch->chan.max_ptn_entries = esnf_max_ptn_entries;
+	ch->chan.ts_enabled = esnf_ts_enabled;
+
+	strncpy(ch->name, tx ? "TX" : "RX", MAX_CHAN_NAME_SIZE - 1);
+
+	dev_dbg(ch->dev, "%s: channel initialized\n", ch->name);
+
+	return 0;
+}
+
+/* Registers the channel with the sniffer core module */
+int channel_register(struct ether_snf_chan *ch, const char *name)
+{
+	int ret;
+
+	ret = snf_channel_add(&ch->chan, name);
+	if (ret < 0)
+		return ret;
+
+	dev_info(ch->dev, "%s channel added\n", ch->name);
+	return 0;
+}
+
+/* Unregisters the channel */
+int channel_unregister(struct ether_snf_chan *ch)
+{
+	int ret;
+
+	ch->chan.stop(&ch->chan);
+	ret = snf_channel_remove(&ch->chan);
+	if (!ret)
+		dev_info(ch->dev, "%s channel removed\n", ch->name);
+	return ret;
+}
+
+/* Process match event data */
+void channel_data_available(struct ether_snf_chan *ch)
+{
+	int ret;
+
+	dev_dbg(ch->dev, "%s match event\n", ch->name);
+
+	read_fifo_data(ch);
+	ret = snf_channel_notify_match(&ch->chan, &ch->evt);
+	if (ret < 0)
+		dev_err(ch->dev, "%s: event notification failed\n", ch->name);
+}
+
+/* Suspend opertion */
+int channel_suspend(struct ether_snf_chan *ch)
+{
+	return snf_channel_suspend(&ch->chan);
+}
+
+/* Resume operation */
+int channel_resume(struct ether_snf_chan *ch)
+{
+	return snf_channel_resume(&ch->chan);
+}
+
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.h b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.h
new file mode 100644
index 0000000..75b942e
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/channel.h
@@ -0,0 +1,80 @@
+/*
+ * Ethernet Mii packet sniffer driver
+ *  - channel interface
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#ifndef _ETHER_SNIFFER_CHANNEL_H_
+#define _ETHER_SNIFFER_CHANNEL_H_
+
+#include <linux/platform_device.h>
+#include <linux/timecounter.h>
+#include "../../core/snf_core.h"
+
+#define MAX_CHAN_NAME_SIZE 5
+
+struct ether_snf_chan {
+	/* Sniffer core structure */
+	struct snf_chan chan;
+	/* Pointer to device struct */
+	struct device *dev;
+	/* Registers */
+	u8 __iomem *regs;
+	/* Command string memory */
+	u32 __iomem *cmd_ram;
+	/* Bit number for the data IRQ */
+	int data_irq_bit;
+	/* Bit number for the FIFO full IRQ */
+	int full_irq_bit;
+	/* Channel enable register */
+	u8 __iomem *reg_enable;
+	/* Data FIFO register */
+	u8 __iomem *reg_fifo;
+	/* Max number of commands in the string */
+	int max_cmds;
+	/* Max matching bytes that can fit in a FIFO block */
+	int fifo_blk_words;
+	/* Number of bytes in the FIFO before the timestamp */
+	int nfb_before;
+	/* Number of bytes in the FIFO after the timestamp */
+	int nfb_after;
+	/* Channel active flag */
+	int started;
+	/* Last raw timestamp from the FIFO */
+	u32 raw_tstamp;
+	/* Channel name (only used by debug messages) */
+	char name[MAX_CHAN_NAME_SIZE];
+	/* Struct to hold data from a packet match */
+	struct snf_match_evt evt;
+	/* Cycle and time counters for tstamp handling */
+	struct cyclecounter cc;
+	struct timecounter tc;
+};
+
+int channel_init(
+		struct ether_snf_chan *ch,
+		struct platform_device *pdev,
+		void *regs,
+		int fifo_blk_words,
+		u32 tstamp_hz,
+		u32 tstamp_bits,
+		int tx);
+int channel_register(struct ether_snf_chan *ch, const char *name);
+int channel_unregister(struct ether_snf_chan *ch);
+void channel_data_available(struct ether_snf_chan *ch);
+int channel_suspend(struct ether_snf_chan *ch);
+int channel_resume(struct ether_snf_chan *ch);
+
+#endif
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/hw.h b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/hw.h
new file mode 100644
index 0000000..edb1093
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/hw.h
@@ -0,0 +1,46 @@
+/*
+ * Ethernet Mii packet sniffer driver
+ *  - register map
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#ifndef _ETHER_SNIFFER_HW_H_
+#define _ETHER_SNIFFER_HW_H_
+
+#include <linux/bitops.h>
+
+/* Registers */
+#define INTERRUPT_ENABLE        0x00
+#define SET_INTERRUPT_ENABLE    0x04
+#define CLEAR_INTERRUPT_ENABLE  0x08
+#define INTERRUPT_STATUS        0x0c
+#define TX_FIFO_DAT             0x10
+#define RX_FIFO_DAT             0x14
+#define TX_FIFO_OCC             0x18
+#define RX_FIFO_OCC             0x1c
+#define TX_SNIFFER_ENABLE       0x20
+#define RX_SNIFFER_ENABLE       0x24
+
+/* IRQ register bits */
+#define TX_DATA_IRQ_BIT         BIT(0)
+#define RX_DATA_IRQ_BIT         BIT(1)
+#define TX_FULL_IRQ_BIT         BIT(2)
+#define RX_FULL_IRQ_BIT         BIT(3)
+
+/* Enable register bits */
+#define ENABLE_BIT              BIT(0)
+
+#endif
+
diff --git a/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/platform.c b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/platform.c
new file mode 100644
index 0000000..e51fadf
--- /dev/null
+++ b/drivers/net/ethernet/linn/pkt-sniffer/backends/ether/platform.c
@@ -0,0 +1,286 @@
+/*
+ * Ethernet Mii packet sniffer driver
+ *
+ * Copyright (C) 2015 Linn Products Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * Written by:
+ * Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/clk.h>
+#include "../../core/snf_core.h"
+#include "hw.h"
+#include "channel.h"
+
+/* Names for the TX and RX channel net interfaces */
+static const char tx_channel_name[] = "snfethtx%d";
+static const char rx_channel_name[] = "snfethrx%d";
+
+struct ether_snf {
+	u8 __iomem *regs;
+	int irq;
+	struct clk *sys_clk;
+	struct clk *ts_clk;
+	struct ether_snf_chan txc;
+	struct ether_snf_chan rxc;
+};
+
+/* Interrupt handler */
+static irqreturn_t esnf_interrupt(int irq, void *dev_id)
+{
+	struct platform_device *pdev = (struct platform_device *)dev_id;
+	struct ether_snf *esnf = (struct ether_snf *)platform_get_drvdata(pdev);
+	u32 irq_status;
+
+	if (unlikely(esnf->irq != irq))
+		return IRQ_NONE;
+
+	irq_status = ioread32(esnf->regs + INTERRUPT_STATUS) &
+				 ioread32(esnf->regs + INTERRUPT_ENABLE);
+
+	dev_dbg(&pdev->dev, "irq: 0x%08x\n", irq_status);
+
+	/* TX FIFO full */
+	if (unlikely(irq_status & TX_FULL_IRQ_BIT))
+		dev_notice(&pdev->dev, "TX FIFO full\n");
+
+	/* RX FIFO full */
+	if (unlikely(irq_status & RX_FULL_IRQ_BIT))
+		dev_notice(&pdev->dev, "RX FIFO full\n");
+
+	/* TX match data available */
+	if (irq_status & TX_DATA_IRQ_BIT) {
+		dev_dbg(&pdev->dev, "TX data\n");
+		channel_data_available(&esnf->txc);
+	}
+
+	/* RX match data available */
+	if (irq_status & RX_DATA_IRQ_BIT) {
+		dev_dbg(&pdev->dev, "RX data\n");
+		channel_data_available(&esnf->rxc);
+	}
+
+	/* Clear interrupts */
+	iowrite32(irq_status, esnf->regs + INTERRUPT_STATUS);
+
+	return IRQ_HANDLED;
+}
+
+/* Called when the packet sniffer device is bound with the driver */
+static int esnf_driver_probe(struct platform_device *pdev)
+{
+	struct ether_snf *esnf;
+	struct resource *res;
+	int ret, irq;
+	u32 fifo_blk_words, ts_hz, ts_bits;
+	void __iomem *regs;
+	struct device_node *ofn = pdev->dev.of_node;
+
+	/* Allocate the device data structure */
+	esnf = devm_kzalloc(&pdev->dev, sizeof(*esnf), GFP_KERNEL);
+	if (!esnf)
+		return -ENOMEM;
+
+	/* Retrieve and remap register memory space */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
+	regs = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
+	esnf->regs = regs;
+
+	if (!ofn)
+		return -ENODEV;
+
+	/* Read requirede properties from the device tree node */
+	ret = of_property_read_u32(
+				ofn,
+				"fifo-block-words",
+				&fifo_blk_words);
+	if (ret < 0)
+		return ret;
+
+	if (((fifo_blk_words - 1) * 4) > MAX_MATCH_BYTES) {
+		dev_err(&pdev->dev,
+			"Invalid FIFO block size entry in device tree\n");
+		return -EINVAL;
+	}
+
+	ret = of_property_read_u32(
+				ofn,
+				"tstamp-bits",
+				&ts_bits);
+	if (ret < 0)
+		return ret;
+
+	/* Enable peripheral bus and timstamp clocks */
+	esnf->sys_clk = devm_clk_get(&pdev->dev, "sys");
+	if (IS_ERR(esnf->sys_clk)) {
+		ret = PTR_ERR(esnf->sys_clk);
+		return ret;
+	}
+	ret = clk_prepare_enable(esnf->sys_clk);
+	if (ret < 0)
+		return ret;
+
+	esnf->ts_clk = devm_clk_get(&pdev->dev, "tstamp");
+	if (IS_ERR(esnf->ts_clk)) {
+		ret = PTR_ERR(esnf->ts_clk);
+		goto fail1;
+	}
+	ret = clk_prepare_enable(esnf->ts_clk);
+	if (ret < 0)
+		goto fail1;
+
+	/* Initialise the TX and RX channels */
+	ts_hz = clk_get_rate(esnf->ts_clk);
+	ret = channel_init(
+			&esnf->txc,
+			pdev,
+			regs,
+			fifo_blk_words,
+			ts_hz,
+			ts_bits,
+			1);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to init TX channel (%d)\n", ret);
+		goto fail2;
+	}
+	ret = channel_init(
+			&esnf->rxc,
+			pdev,
+			regs,
+			fifo_blk_words,
+			ts_hz,
+			ts_bits,
+			0);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to init RX channel (%d)\n", ret);
+		goto fail2;
+	}
+
+	/* Register the channels with the sniffer core module */
+	ret = channel_register(&esnf->txc, tx_channel_name);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register TX chan (%d)\n", ret);
+		goto fail2;
+	}
+	ret = channel_register(&esnf->rxc, rx_channel_name);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register RX chan (%d)\n", ret);
+		goto fail3;
+	}
+
+	platform_set_drvdata(pdev, esnf);
+
+	/* Register the interrupt handler */
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0)
+		goto fail4;
+	esnf->irq = irq;
+	ret = devm_request_irq(
+			&pdev->dev,
+			irq,
+			esnf_interrupt,
+			0,
+			KBUILD_MODNAME,
+			pdev);
+	if (ret < 0)
+		goto fail4;
+
+	return 0;
+
+fail4:
+	channel_unregister(&esnf->rxc);
+fail3:
+	channel_unregister(&esnf->txc);
+fail2:
+	clk_disable_unprepare(esnf->ts_clk);
+fail1:
+	clk_disable_unprepare(esnf->sys_clk);
+	return ret;
+}
+
+/* Called when the packet sniffer device unregisters with the driver */
+static int esnf_driver_remove(struct platform_device *pdev)
+{
+	struct ether_snf *esnf = (struct ether_snf *)platform_get_drvdata(pdev);
+	int ret;
+
+	ret = channel_unregister(&esnf->txc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to unregister TX chan (%d)\n", ret);
+		return ret;
+	}
+	ret = channel_unregister(&esnf->rxc);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to unregister RX chan (%d)\n", ret);
+		return ret;
+	}
+	clk_disable_unprepare(esnf->ts_clk);
+	clk_disable_unprepare(esnf->sys_clk);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+/* Driver suspend method */
+static int esnf_driver_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct ether_snf *esnf = (struct ether_snf *)platform_get_drvdata(pdev);
+
+	channel_suspend(&esnf->txc);
+	channel_suspend(&esnf->rxc);
+	return 0;
+}
+
+/* Driver resume method */
+static int esnf_driver_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct ether_snf *esnf = (struct ether_snf *)platform_get_drvdata(pdev);
+
+	channel_resume(&esnf->txc);
+	channel_resume(&esnf->rxc);
+	return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(esnf_pm_ops, esnf_driver_suspend, esnf_driver_resume);
+#endif
+
+static const struct of_device_id esnf_of_match_table[] = {
+	{ .compatible = "linn,eth-packet-sniffer" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, esnf_of_match_table);
+
+static struct platform_driver esnf_platform_driver = {
+	.driver = {
+		.name           = KBUILD_MODNAME,
+#ifdef CONFIG_PM
+		.pm	        = &esnf_pm_ops,
+#endif
+		.of_match_table = esnf_of_match_table,
+	},
+	.probe = esnf_driver_probe,
+	.remove = esnf_driver_remove,
+};
+
+module_platform_driver(esnf_platform_driver);
+
+MODULE_DESCRIPTION("Linn Ethernet Packet Sniffer");
+MODULE_AUTHOR("Linn Products Ltd");
+MODULE_LICENSE("GPL v2");
+
-- 
1.9.1

Re: [PATCH v3 2/3] Packet sniffer core framework

[David Miller]

From: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
Date: Mon, 23 Feb 2015 14:26:21 +0000

> +	spin_lock_irqsave(&priv->lock, flags);
> +	/* Stop the hardware */
> +	sch->stop(sch);
> +	/* Set the new command pattern */
> +	ret = sch->set_pattern(sch, skb->data, skb->len / 2);
> +	/* Restart the hardware */
> +	sch->start(sch);
> +	spin_unlock_irqrestore(&priv->lock, flags);

These comments are excessive.

When someone calls ops->stop() what are they supposed to think the
thing does?  Open a can of tuna?  Mow the lawn?  Wash the dishes?  No,
it stops the thing.  Everyone understands that and you don't have to
explicitly say it.

Saying "stop the hardware" does not add anything to the source code
that is not already implicitly there.  They just take up space and
keep more useful information from being displayed at once on the
screen.  Please remove all of these things.

Thanks.

Re: [PATCH v3 3/3] Linn Ethernet packet sniffer driver

[David Miller]

From: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
Date: Mon, 23 Feb 2015 14:26:22 +0000

> Driver for the Ethernet Mii packet sniffer H/W module found in
> the IMG Pistachio SoC.
> 
> Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>

You really have to explain what this thing does, how it is used,
what APIs are made use of to maniulate this device, etc.

Nobody knows what the packet sniffer module by your company is.

I also anticipate that once you describe adequately how this thing
behaves I won't like it, and I'll prefer that you integrate support
for your device using an exising facility such as AF_PACKET,
extending it if need be.

I am very far away from applying this series at this point, it needs
a lot more work and explanations.

Re: [PATCH v3 2/3] Packet sniffer core framework

[Stathis Voukelatos]

On 23/02/15 21:37, David Miller wrote:
> From: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
> Date: Mon, 23 Feb 2015 14:26:21 +0000
>
>> +	spin_lock_irqsave(&priv->lock, flags);
>> +	/* Stop the hardware */
>> +	sch->stop(sch);
>> +	/* Set the new command pattern */
>> +	ret = sch->set_pattern(sch, skb->data, skb->len / 2);
>> +	/* Restart the hardware */
>> +	sch->start(sch);
>> +	spin_unlock_irqrestore(&priv->lock, flags);
>
> These comments are excessive.
>
> When someone calls ops->stop() what are they supposed to think the
> thing does?  Open a can of tuna?  Mow the lawn?  Wash the dishes?  No,
> it stops the thing.  Everyone understands that and you don't have to
> explicitly say it.
>
> Saying "stop the hardware" does not add anything to the source code
> that is not already implicitly there.  They just take up space and
> keep more useful information from being displayed at once on the
> screen.  Please remove all of these things.
>
> Thanks.
>

Will remove the comments in the next version of the patch set.

Thank you,
Stathis

Re: [PATCH v3 3/3] Linn Ethernet packet sniffer driver

[Stathis Voukelatos]

On 23/02/15 21:38, David Miller wrote:
> From: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
> Date: Mon, 23 Feb 2015 14:26:22 +0000
>
>> Driver for the Ethernet Mii packet sniffer H/W module found in
>> the IMG Pistachio SoC.
>>
>> Signed-off-by: Stathis Voukelatos <stathis.voukelatos@linn.co.uk>
>
> You really have to explain what this thing does, how it is used,
> what APIs are made use of to maniulate this device, etc.
>
> Nobody knows what the packet sniffer module by your company is.
>

I tried to provide a description of the device in the cover letter. I 
will expand it and also include it in a suitable place in the actual 
source.

> I also anticipate that once you describe adequately how this thing
> behaves I won't like it, and I'll prefer that you integrate support
> for your device using an exising facility such as AF_PACKET,
> extending it if need be.
>

The driver actually relies on AF_PACKET for accessing the device. I will 
add some documentation to make the usage and API clearer.

> I am very far away from applying this series at this point, it needs
> a lot more work and explanations.
>

Thank you,
Stathis