[PATCH 3/8] can: CAN Network device driver and SYSFS interface

[Wolfgang Grandegger]

The CAN network device driver interface provides a generic interface to
setup, configure and monitor CAN network devices. It exports a set of
common data structures and functions, which all real CAN network device
drivers should use. Please have a look to the SJA1000 or MSCAN driver
to understand how to use them. The name of the module is can-dev.ko.

Furthermore adds a SYSFS interface to set and get CAN device properties.
When the CAN device is registered, a set of SYSFS files is created in
"/sys/class/net/canX/". These files allow to set and get device
properties like bit-timing parameters, state, controller mode and CAN
statistics.

For further information please check "Documentation/networking/can.txt"

Signed-off-by: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
Signed-off-by: Oliver Hartkopp <oliver.hartkopp@xxxxxxxxxxxxx>
---
 drivers/net/can/Kconfig  |   23 ++
 drivers/net/can/Makefile |    5 +
 drivers/net/can/dev.c    |  528 ++++++++++++++++++++++++++++++++++++++++++++++
 drivers/net/can/sysfs.c  |  509 ++++++++++++++++++++++++++++++++++++++++++++
 drivers/net/can/sysfs.h  |   24 ++
 include/linux/can/dev.h  |  136 ++++++++++++
 6 files changed, 1225 insertions(+), 0 deletions(-)
 create mode 100644 drivers/net/can/dev.c
 create mode 100644 drivers/net/can/sysfs.c
 create mode 100644 drivers/net/can/sysfs.h
 create mode 100644 include/linux/can/dev.h

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index 57def0d..d609895 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -12,6 +12,29 @@ config CAN_VCAN
 	  This driver can also be built as a module.  If so, the module
 	  will be called vcan.
 
+config CAN_DEV
+	tristate "Platform CAN drivers with SYSFS support"
+	depends on CAN && SYSFS
+	default Y
+	---help---
+	  Enables the common framework for platform CAN drivers with SYSFS
+	  support. This is the standard library for CAN drivers.
+	  If unsure, say Y.
+
+config CAN_CALC_BITTIMING
+	bool "CAN bit-timing calculation"
+	depends on CAN_DEV
+	default Y
+	---help---
+	  If enabled, CAN bit-timing parameters will be calculated for the
+	  bit-rate specified via SYSFS file "bitrate" when the device gets
+	  started. This works fine for the most common CAN controllers
+	  with standard bit-rates but may fail for exotic bit-rates or CAN
+	  source clock frequencies. Disabling saves some space, but then the
+	  bit-timing parameters must be specified directly using the SYSFS
+	  files "tq", "prop_seg", "phase_seg1", "phase_seg2" and "sjw".
+	  If unsure, say Y.
+
 config CAN_DEBUG_DEVICES
 	bool "CAN devices debugging messages"
 	depends on CAN
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index c4bead7..557114b 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -3,3 +3,8 @@
 #
 
 obj-$(CONFIG_CAN_VCAN)		+= vcan.o
+
+obj-$(CONFIG_CAN_DEV)		+= can-dev.o
+can-dev-y			:= dev.o sysfs.o
+
+ccflags-$(CONFIG_CAN_DEBUG_DEVICES) := -DDEBUG
diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
new file mode 100644
index 0000000..faa75d1
--- /dev/null
+++ b/drivers/net/can/dev.c
@@ -0,0 +1,528 @@
+/*
+ * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
+ * Copyright (C) 2006 Andrey Volkov, Varma Electronics
+ * Copyright (C) 2008 Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/module.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <net/rtnetlink.h>
+
+#include "sysfs.h"
+
+#define MOD_DESC "CAN device driver interface"
+
+MODULE_DESCRIPTION(MOD_DESC);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>");
+
+#ifdef CONFIG_CAN_CALC_BITTIMING
+#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
+
+/*
+ * Bit-timing calculation derived from:
+ *
+ * Code based on LinCAN sources and H8S2638 project
+ * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
+ * Copyright 2005      Stanislav Marek
+ * email: pisa@xxxxxxxxxxxxxxxx
+ */
+static int can_update_spt(const struct can_bittiming_const *btc,
+			  int sampl_pt, int tseg, int *tseg1, int *tseg2)
+{
+	*tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
+	if (*tseg2 < btc->tseg2_min)
+		*tseg2 = btc->tseg2_min;
+	if (*tseg2 > btc->tseg2_max)
+		*tseg2 = btc->tseg2_max;
+	*tseg1 = tseg - *tseg2;
+	if (*tseg1 > btc->tseg1_max) {
+		*tseg1 = btc->tseg1_max;
+		*tseg2 = tseg - *tseg1;
+	}
+	return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
+}
+
+static int can_calc_bittiming(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->bittiming;
+	const struct can_bittiming_const *btc = priv->bittiming_const;
+	long rate, best_rate = 0;
+	long best_error = 1000000000, error = 0;
+	int best_tseg = 0, best_brp = 0, brp = 0;
+	int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
+	int spt_error = 1000, spt = 0, sampl_pt;
+	u64 v64;
+
+	if (!priv->bittiming_const)
+		return -ENOTSUPP;
+
+	/* Use CIA recommended sample points */
+	if (bt->sample_point) {
+		sampl_pt = bt->sample_point;
+	} else {
+		if (bt->bitrate > 800000)
+			sampl_pt = 750;
+		else if (bt->bitrate > 500000)
+			sampl_pt = 800;
+		else
+			sampl_pt = 875;
+	}
+
+	/* tseg even = round down, odd = round up */
+	for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
+	     tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
+		tsegall = 1 + tseg / 2;
+		/* Compute all possible tseg choices (tseg=tseg1+tseg2) */
+		brp = bt->clock / (tsegall * bt->bitrate) + tseg % 2;
+		/* chose brp step which is possible in system */
+		brp = (brp / btc->brp_inc) * btc->brp_inc;
+		if ((brp < btc->brp_min) || (brp > btc->brp_max))
+			continue;
+		rate = bt->clock / (brp * tsegall);
+		error = bt->bitrate - rate;
+		/* tseg brp biterror */
+		if (error < 0)
+			error = -error;
+		if (error > best_error)
+			continue;
+		best_error = error;
+		if (error == 0) {
+			spt = can_update_spt(btc, sampl_pt, tseg / 2,
+					     &tseg1, &tseg2);
+			error = sampl_pt - spt;
+			if (error < 0)
+				error = -error;
+			if (error > spt_error)
+				continue;
+			spt_error = error;
+		}
+		best_tseg = tseg / 2;
+		best_brp = brp;
+		best_rate = rate;
+		if (error == 0)
+			break;
+	}
+
+	if (best_error) {
+		/* Error in one-tenth of a percent */
+		error = (best_error * 1000) / bt->bitrate;
+		if (error > CAN_CALC_MAX_ERROR) {
+			dev_err(ND2D(dev), "bitrate error %ld.%ld%% too high\n",
+				error / 10, error % 10);
+			return -EDOM;
+		} else {
+			dev_warn(ND2D(dev), "bitrate error %ld.%ld%%\n",
+				 error / 10, error % 10);
+		}
+	}
+
+	spt = can_update_spt(btc, sampl_pt, best_tseg, &tseg1, &tseg2);
+
+	v64 = (u64)best_brp * 1000000000UL;
+	do_div(v64, bt->clock);
+	bt->tq = (u32)v64;
+	bt->prop_seg = tseg1 / 2;
+	bt->phase_seg1 = tseg1 - bt->prop_seg;
+	bt->phase_seg2 = tseg2;
+	bt->sjw = 1;
+	bt->brp = best_brp;
+
+	return 0;
+}
+#else /* !CONFIG_CAN_CALC_BITTIMING */
+static int can_calc_bittiming(struct net_device *dev)
+{
+	dev_err(ND2D(dev), "bit-timing calculation not available\n");
+	return -EINVAL;
+}
+#endif /* CONFIG_CAN_CALC_BITTIMING */
+
+int can_sample_point(struct can_bittiming *bt)
+{
+	return ((bt->prop_seg + bt->phase_seg1 + 1) * 1000) /
+		(bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1);
+}
+
+static int can_fixup_bittiming(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->bittiming;
+	const struct can_bittiming_const *btc = priv->bittiming_const;
+	int tseg1, alltseg;
+	u32 bitrate;
+	u64 brp64;
+
+	if (!priv->bittiming_const)
+		return -ENOTSUPP;
+
+	tseg1 = bt->prop_seg + bt->phase_seg1;
+	if (bt->sjw > btc->sjw_max ||
+	    tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
+	    bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
+		return -EINVAL;
+
+	brp64 = (u64)bt->clock * (u64)bt->tq;
+	if (btc->brp_inc > 1)
+		do_div(brp64, btc->brp_inc);
+	brp64 += 500000000UL - 1;
+	do_div(brp64, 1000000000UL); /* the practicable BRP */
+	if (btc->brp_inc > 1)
+		brp64 *= btc->brp_inc;
+	bt->brp = (u32)brp64;
+
+	if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
+		return -EINVAL;
+
+	alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
+	bitrate = bt->clock / (bt->brp * alltseg);
+	bt->bitrate = bitrate;
+
+	return 0;
+}
+
+/*
+ * Set CAN bit-timing for the device
+ *
+ * This functions should be called in the open function of the device
+ * driver to determine, check and set appropriate bit-timing parameters.
+ */
+int can_set_bittiming(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	int err;
+
+	/* Check if bit-timing parameters have been pre-defined */
+	if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
+		dev_err(ND2D(dev), "bit-timing not yet defined\n");
+		return -EINVAL;
+	}
+
+	/* Check if the CAN device has bit-timing parameters */
+	if (priv->bittiming_const) {
+
+		/* Check if bit-timing parameters have already been set */
+		if (priv->bittiming.tq && priv->bittiming.bitrate)
+			return 0;
+
+		/* Non-expert mode? Check if the bitrate has been pre-defined */
+		if (!priv->bittiming.tq)
+			/* Determine bit-timing parameters */
+			err = can_calc_bittiming(dev);
+		else
+			/* Check bit-timing params and calculate proper brp */
+			err = can_fixup_bittiming(dev);
+		if (err)
+			return err;
+	}
+
+	if (priv->do_set_bittiming) {
+		/* Finally, set the bit-timing registers */
+		err = priv->do_set_bittiming(dev);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(can_set_bittiming);
+
+static void can_setup(struct net_device *dev)
+{
+	dev->type = ARPHRD_CAN;
+	dev->mtu = sizeof(struct can_frame);
+	dev->hard_header_len = 0;
+	dev->addr_len = 0;
+	dev->tx_queue_len = 10;
+
+	/* New-style flags. */
+	dev->flags = IFF_NOARP;
+	dev->features = NETIF_F_NO_CSUM;
+}
+
+/*
+ * Allocate and setup space for the CAN network device
+ */
+struct net_device *alloc_candev(int sizeof_priv)
+{
+	struct net_device *dev;
+	struct can_priv *priv;
+
+	dev = alloc_netdev(sizeof_priv, "can%d", can_setup);
+	if (!dev)
+		return NULL;
+
+	priv = netdev_priv(dev);
+
+	priv->state = CAN_STATE_STOPPED;
+	spin_lock_init(&priv->irq_lock);
+
+	init_timer(&priv->timer);
+	priv->timer.expires = 0;
+
+	return dev;
+}
+EXPORT_SYMBOL_GPL(alloc_candev);
+
+/*
+ * Allocate space of the CAN network device
+ */
+void free_candev(struct net_device *dev)
+{
+	free_netdev(dev);
+}
+EXPORT_SYMBOL_GPL(free_candev);
+
+/*
+ * Register the CAN network device
+ */
+int register_candev(struct net_device *dev)
+{
+	int err;
+
+	err = register_netdev(dev);
+	if (err)
+		return err;
+
+	can_create_sysfs(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(register_candev);
+
+/*
+ * Unregister the CAN network device
+ */
+void unregister_candev(struct net_device *dev)
+{
+	can_remove_sysfs(dev);
+	unregister_netdev(dev);
+}
+EXPORT_SYMBOL_GPL(unregister_candev);
+
+/*
+ * Local echo of CAN messages
+ *
+ * CAN network devices *should* support a local echo functionality
+ * (see Documentation/networking/can.txt). To test the handling of CAN
+ * interfaces that do not support the local echo both driver types are
+ * implemented. In the case that the driver does not support the echo
+ * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
+ * to perform the echo as a fallback solution.
+ */
+
+static void can_flush_echo_skb(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	int i;
+
+	for (i = 0; i < CAN_ECHO_SKB_MAX; i++) {
+		if (priv->echo_skb[i]) {
+			kfree_skb(priv->echo_skb[i]);
+			priv->echo_skb[i] = NULL;
+			stats->tx_dropped++;
+			stats->tx_aborted_errors++;
+		}
+	}
+}
+
+/*
+ * Put the skb on the stack to be looped backed locally lateron
+ *
+ * The function is typically called in the start_xmit function
+ * of the device driver.
+ */
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	/* set flag whether this packet has to be looped back */
+	if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
+		kfree_skb(skb);
+		return;
+	}
+
+	if (!priv->echo_skb[idx]) {
+		struct sock *srcsk = skb->sk;
+
+		if (atomic_read(&skb->users) != 1) {
+			struct sk_buff *old_skb = skb;
+
+			skb = skb_clone(old_skb, GFP_ATOMIC);
+			kfree_skb(old_skb);
+			if (!skb)
+				return;
+		} else
+			skb_orphan(skb);
+
+		skb->sk = srcsk;
+
+		/* make settings for echo to reduce code in irq context */
+		skb->protocol = htons(ETH_P_CAN);
+		skb->pkt_type = PACKET_BROADCAST;
+		skb->ip_summed = CHECKSUM_UNNECESSARY;
+		skb->dev = dev;
+
+		/* save this skb for tx interrupt echo handling */
+		priv->echo_skb[idx] = skb;
+	} else {
+		/* locking problem with netif_stop_queue() ?? */
+		printk(KERN_ERR "%s: %s: BUG! echo_skb is occupied!\n",
+		       dev->name, __func__);
+		kfree_skb(skb);
+	}
+}
+EXPORT_SYMBOL_GPL(can_put_echo_skb);
+
+/*
+ * Get the skb from the stack and loop it back locally
+ *
+ * The function is typically called when the TX done interrupt
+ * is handled in the device driver.
+ */
+void can_get_echo_skb(struct net_device *dev, int idx)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if ((dev->flags & IFF_ECHO) && priv->echo_skb[idx]) {
+		netif_rx(priv->echo_skb[idx]);
+		priv->echo_skb[idx] = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(can_get_echo_skb);
+
+/*
+ * CAN device restart for bus-off recovery
+ */
+int can_restart_now(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	struct net_device_stats *stats = &dev->stats;
+	struct sk_buff *skb;
+	struct can_frame *cf;
+	int err;
+
+	if (netif_carrier_ok(dev))
+		netif_carrier_off(dev);
+
+	/* Cancel restart in progress */
+	if (priv->timer.expires) {
+		del_timer(&priv->timer);
+		priv->timer.expires = 0; /* mark inactive timer */
+	}
+
+	can_flush_echo_skb(dev);
+
+	err = priv->do_set_mode(dev, CAN_MODE_START);
+	if (err)
+		return err;
+
+	netif_carrier_on(dev);
+
+	dev_dbg(ND2D(dev), "restarted\n");
+	priv->can_stats.restarts++;
+
+	/* send restart message upstream */
+	skb = dev_alloc_skb(sizeof(struct can_frame));
+	if (skb == NULL)
+		return -ENOMEM;
+	skb->dev = dev;
+	skb->protocol = htons(ETH_P_CAN);
+	cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
+	memset(cf, 0, sizeof(struct can_frame));
+	cf->can_id = CAN_ERR_FLAG | CAN_ERR_RESTARTED;
+	cf->can_dlc = CAN_ERR_DLC;
+
+	netif_rx(skb);
+
+	dev->last_rx = jiffies;
+	stats->rx_packets++;
+	stats->rx_bytes += cf->can_dlc;
+
+	return 0;
+}
+
+static void can_restart_after(unsigned long data)
+{
+	struct net_device *dev = (struct net_device *)data;
+	struct can_priv *priv = netdev_priv(dev);
+
+	priv->timer.expires = 0; /* mark inactive timer */
+	can_restart_now(dev);
+}
+
+/*
+ * CAN bus-off
+ *
+ * This functions should be called when the device goes bus-off to
+ * tell the netif layer that no more packets can be sent or received.
+ * If enabled, a timer is started to trigger bus-off recovery.
+ */
+void can_bus_off(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	dev_dbg(ND2D(dev), "bus-off\n");
+
+	netif_carrier_off(dev);
+
+	if (priv->restart_ms > 0 && !priv->timer.expires) {
+
+		priv->timer.function = can_restart_after;
+		priv->timer.data = (unsigned long)dev;
+		priv->timer.expires =
+			jiffies + (priv->restart_ms * HZ) / 1000;
+		add_timer(&priv->timer);
+	}
+}
+EXPORT_SYMBOL_GPL(can_bus_off);
+
+/*
+ * Cleanup function before the device gets closed.
+ *
+ * This functions should be called in the close function of the device
+ * driver.
+ */
+void can_close_cleanup(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (priv->timer.expires) {
+		del_timer(&priv->timer);
+		priv->timer.expires = 0;
+	}
+
+	can_flush_echo_skb(dev);
+}
+EXPORT_SYMBOL_GPL(can_close_cleanup);
+
+static __init int can_dev_init(void)
+{
+	printk(KERN_INFO MOD_DESC "\n");
+
+	return 0;
+}
+module_init(can_dev_init);
+
+static __exit void can_dev_exit(void)
+{
+}
+module_exit(can_dev_exit);
diff --git a/drivers/net/can/sysfs.c b/drivers/net/can/sysfs.c
new file mode 100644
index 0000000..746f641
--- /dev/null
+++ b/drivers/net/can/sysfs.c
@@ -0,0 +1,509 @@
+/*
+ * Copyright (C) 2007-2008 Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/capability.h>
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/if_arp.h>
+#include <net/sock.h>
+#include <linux/rtnetlink.h>
+
+#include <linux/can.h>
+#include <linux/can/dev.h>
+
+#include "sysfs.h"
+
+#ifdef CONFIG_SYSFS
+
+/*
+ * SYSFS access functions and attributes. Use same locking as
+ * net/core/net-sysfs.c does.
+ */
+static inline int dev_isalive(const struct net_device *dev)
+{
+	return dev->reg_state <= NETREG_REGISTERED;
+}
+
+/* use same locking rules as GIF* ioctl's */
+static ssize_t can_dev_show(struct device *d,
+			    struct device_attribute *attr, char *buf,
+			    ssize_t (*fmt)(struct net_device *, char *))
+{
+	struct net_device *dev = to_net_dev(d);
+	ssize_t ret = -EINVAL;
+
+	read_lock(&dev_base_lock);
+	if (dev_isalive(dev))
+		ret = (*fmt)(dev, buf);
+	read_unlock(&dev_base_lock);
+
+	return ret;
+}
+
+/* generate a show function for simple field */
+#define CAN_DEV_SHOW(field, fmt_string)					\
+static ssize_t fmt_can_##field(struct net_device *dev, char *buf)	\
+{									\
+	struct can_priv *priv = netdev_priv(dev);			\
+	return sprintf(buf, fmt_string, priv->field);			\
+}									\
+static ssize_t show_can_##field(struct device *d,			\
+				struct device_attribute *attr,		\
+				char *buf)				\
+{									\
+	return can_dev_show(d, attr, buf, fmt_can_##field);		\
+}
+
+/* use same locking and permission rules as SIF* ioctl's */
+static ssize_t can_dev_store(struct device *d, struct device_attribute *attr,
+			     const char *buf, size_t len,
+			     int (*set)(struct net_device *, unsigned long))
+{
+	struct net_device *dev = to_net_dev(d);
+	unsigned long new;
+	int ret = -EINVAL;
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	ret = strict_strtoul(buf, 0, &new);
+	if (ret)
+		goto out;
+
+	rtnl_lock();
+	if (dev_isalive(dev)) {
+		ret = (*set)(dev, new);
+		if (!ret)
+			ret = len;
+	}
+	rtnl_unlock();
+out:
+	return ret;
+}
+
+#define CAN_CREATE_FILE(_dev, _name)					\
+	if (device_create_file(&_dev->dev, &dev_attr_##_name))		\
+		dev_err(ND2D(_dev),					\
+			"Couldn't create device file for ##_name\n")
+
+#define CAN_REMOVE_FILE(_dev, _name)					\
+	device_remove_file(&_dev->dev, &dev_attr_##_name)		\
+
+CAN_DEV_SHOW(ctrlmode, "0x%x\n");
+
+static int change_can_ctrlmode(struct net_device *dev, unsigned long ctrlmode)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	int err = 0;
+
+	if (priv->state != CAN_STATE_STOPPED)
+		return -EBUSY;
+
+	if (priv->do_set_ctrlmode)
+		err = priv->do_set_ctrlmode(dev, ctrlmode);
+
+	if (!err)
+		priv->ctrlmode = ctrlmode;
+
+	return err;
+}
+
+static ssize_t store_can_ctrlmode(struct device *dev,
+				  struct device_attribute *attr,
+				  const char *buf, size_t len)
+{
+	return can_dev_store(dev, attr, buf, len, change_can_ctrlmode);
+}
+
+static DEVICE_ATTR(can_ctrlmode, S_IRUGO | S_IWUSR,
+		   show_can_ctrlmode, store_can_ctrlmode);
+
+static const char *can_state_names[] = {
+	"active", "bus-warn", "bus-pass" , "bus-off",
+	"stopped", "sleeping", "unkown"
+};
+
+static ssize_t printf_can_state(struct net_device *dev, char *buf)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	enum can_state state;
+	int err = 0;
+
+	if (priv->do_get_state) {
+		err = priv->do_get_state(dev, &state);
+		if (err)
+			goto out;
+		priv->state = state;
+	} else
+		state = priv->state;
+
+	if (state >= ARRAY_SIZE(can_state_names))
+		state = ARRAY_SIZE(can_state_names) - 1;
+	err = sprintf(buf, "%s\n", can_state_names[state]);
+out:
+	return err;
+}
+
+static ssize_t show_can_state(struct device *d,
+			      struct device_attribute *attr, char *buf)
+{
+	return can_dev_show(d, attr, buf, printf_can_state);
+}
+
+static DEVICE_ATTR(can_state, S_IRUGO, show_can_state, NULL);
+
+CAN_DEV_SHOW(restart_ms, "%d\n");
+
+static int change_can_restart_ms(struct net_device *dev, unsigned long ms)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (priv->restart_ms < 0)
+		return -EOPNOTSUPP;
+	priv->restart_ms = ms;
+	return 0;
+}
+
+static ssize_t store_can_restart_ms(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t len)
+{
+	return can_dev_store(dev, attr, buf, len, change_can_restart_ms);
+}
+
+static DEVICE_ATTR(can_restart_ms, S_IRUGO | S_IWUSR,
+		   show_can_restart_ms, store_can_restart_ms);
+
+static ssize_t printf_can_echo(struct net_device *dev, char *buf)
+{
+	return sprintf(buf, "%d\n", dev->flags & IFF_ECHO ? 1 : 0);
+}
+
+static ssize_t show_can_echo(struct device *d,
+			  struct device_attribute *attr, char *buf)
+{
+	return can_dev_show(d, attr, buf, printf_can_echo);
+}
+
+static int change_can_echo(struct net_device *dev, unsigned long on)
+{
+	if (on)
+		dev->flags |= IFF_ECHO;
+	else
+		dev->flags &= ~IFF_ECHO;
+	return 0;
+}
+
+static ssize_t store_can_echo(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t len)
+{
+	return can_dev_store(dev, attr, buf, len, change_can_echo);
+}
+
+static DEVICE_ATTR(can_echo, S_IRUGO | S_IWUSR, show_can_echo, store_can_echo);
+
+static int change_can_restart(struct net_device *dev, unsigned long on)
+{
+	return can_restart_now(dev);
+}
+
+static ssize_t store_can_restart(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t len)
+{
+	return can_dev_store(dev, attr, buf, len, change_can_restart);
+}
+
+static DEVICE_ATTR(can_restart, S_IWUSR, NULL, store_can_restart);
+
+/* Show a given attribute if the CAN bittiming group */
+static ssize_t can_btc_show(const struct device *d,
+			    struct device_attribute *attr, char *buf,
+			    unsigned long offset)
+{
+	struct net_device *dev = to_net_dev(d);
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_bittiming_const *btc = priv->bittiming_const;
+	ssize_t ret = -EINVAL;
+
+	WARN_ON(offset >= sizeof(struct can_bittiming_const) ||
+		offset % sizeof(u32) != 0);
+
+	read_lock(&dev_base_lock);
+	if (dev_isalive(dev) && btc)
+		ret = sprintf(buf, "%d\n",
+			      *(u32 *)(((u8 *)btc) + offset));
+
+	read_unlock(&dev_base_lock);
+	return ret;
+}
+
+/* Generate a read-only bittiming const attribute */
+#define CAN_BT_CONST_ENTRY(name)					\
+static ssize_t show_##name(struct device *d,				\
+			   struct device_attribute *attr, char *buf) 	\
+{									\
+	return can_btc_show(d, attr, buf,				\
+			    offsetof(struct can_bittiming_const, name));\
+}									\
+static DEVICE_ATTR(hw_##name, S_IRUGO, show_##name, NULL)
+
+CAN_BT_CONST_ENTRY(tseg1_min);
+CAN_BT_CONST_ENTRY(tseg1_max);
+CAN_BT_CONST_ENTRY(tseg2_min);
+CAN_BT_CONST_ENTRY(tseg2_max);
+CAN_BT_CONST_ENTRY(sjw_max);
+CAN_BT_CONST_ENTRY(brp_min);
+CAN_BT_CONST_ENTRY(brp_max);
+CAN_BT_CONST_ENTRY(brp_inc);
+
+static ssize_t can_bt_show(const struct device *d,
+			   struct device_attribute *attr, char *buf,
+			   unsigned long offset)
+{
+	struct net_device *dev = to_net_dev(d);
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->bittiming;
+	ssize_t ret = -EINVAL;
+	u32 *ptr, val;
+
+	WARN_ON(offset >= sizeof(struct can_bittiming) ||
+		offset % sizeof(u32) != 0);
+
+	read_lock(&dev_base_lock);
+	if (dev_isalive(dev)) {
+		ptr = (u32 *)(((u8 *)bt) + offset);
+		if (ptr == &bt->sample_point &&
+		    priv->state != CAN_STATE_STOPPED)
+			val = can_sample_point(bt);
+		else
+			val = *ptr;
+		ret = sprintf(buf, "%d\n", val);
+	}
+	read_unlock(&dev_base_lock);
+	return ret;
+}
+
+static ssize_t can_bt_store(const struct device *d,
+			    struct device_attribute *attr,
+			    const char *buf, size_t count,
+			    unsigned long offset)
+{
+	struct net_device *dev = to_net_dev(d);
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_bittiming *bt = &priv->bittiming;
+	unsigned long new;
+	ssize_t ret = -EINVAL;
+	u32 *ptr;
+
+	if (priv->state != CAN_STATE_STOPPED)
+		return -EBUSY;
+
+	WARN_ON(offset >= sizeof(struct can_bittiming) ||
+		offset % sizeof(u32) != 0);
+
+	ret = strict_strtoul(buf, 0, &new);
+	if (ret)
+		goto out;
+
+	ptr = (u32 *)(((u8 *)bt) + offset);
+	rtnl_lock();
+	if (dev_isalive(dev)) {
+		*ptr = (u32)new;
+
+		if ((ptr == &bt->bitrate) || (ptr == &bt->sample_point)) {
+			bt->tq = 0;
+			bt->brp = 0;
+			bt->sjw = 0;
+			bt->prop_seg = 0;
+			bt->phase_seg1 = 0;
+			bt->phase_seg2 = 0;
+		} else {
+			bt->bitrate = 0;
+			bt->sample_point = 0;
+		}
+		ret = count;
+	}
+	rtnl_unlock();
+out:
+	return ret;
+}
+
+#define CAN_BT_ENTRY_RO(name)						\
+static ssize_t show_##name(struct device *d,				\
+			   struct device_attribute *attr, char *buf) 	\
+{									\
+	return can_bt_show(d, attr, buf,				\
+			   offsetof(struct can_bittiming, name));	\
+}									\
+static DEVICE_ATTR(hw_##name, S_IRUGO, show_##name, NULL)
+
+CAN_BT_ENTRY_RO(clock);
+
+#define CAN_BT_ENTRY(name)						\
+static ssize_t show_##name(struct device *d,				\
+			   struct device_attribute *attr, char *buf) 	\
+{									\
+	return can_bt_show(d, attr, buf,				\
+			   offsetof(struct can_bittiming, name));	\
+}									\
+static ssize_t store_##name(struct device *d,				\
+			    struct device_attribute *attr,		\
+			    const char *buf, size_t count)		\
+{									\
+	return can_bt_store(d, attr, buf, count,			\
+			    offsetof(struct can_bittiming, name));	\
+}									\
+static DEVICE_ATTR(name, S_IRUGO | S_IWUSR, show_##name, store_##name)
+
+CAN_BT_ENTRY(bitrate);
+CAN_BT_ENTRY(sample_point);
+CAN_BT_ENTRY(tq);
+CAN_BT_ENTRY(prop_seg);
+CAN_BT_ENTRY(phase_seg1);
+CAN_BT_ENTRY(phase_seg2);
+CAN_BT_ENTRY(sjw);
+
+static struct attribute *can_bittiming_attrs[] = {
+	&dev_attr_hw_tseg1_min.attr,
+	&dev_attr_hw_tseg1_max.attr,
+	&dev_attr_hw_tseg2_max.attr,
+	&dev_attr_hw_tseg2_min.attr,
+	&dev_attr_hw_sjw_max.attr,
+	&dev_attr_hw_brp_min.attr,
+	&dev_attr_hw_brp_max.attr,
+	&dev_attr_hw_brp_inc.attr,
+	&dev_attr_hw_clock.attr,
+	&dev_attr_bitrate.attr,
+	&dev_attr_sample_point.attr,
+	&dev_attr_tq.attr,
+	&dev_attr_prop_seg.attr,
+	&dev_attr_phase_seg1.attr,
+	&dev_attr_phase_seg2.attr,
+	&dev_attr_sjw.attr,
+	NULL
+};
+
+static struct attribute_group can_bittiming_group = {
+	.name = "can_bittiming",
+	.attrs = can_bittiming_attrs,
+};
+
+/* Show a given attribute in the CAN statistics group */
+static ssize_t can_stat_show(const struct device *d,
+			     struct device_attribute *attr, char *buf,
+			     unsigned long offset)
+{
+	struct net_device *dev = to_net_dev(d);
+	struct can_priv *priv = netdev_priv(dev);
+	struct can_device_stats *stats = &priv->can_stats;
+	ssize_t ret = -EINVAL;
+
+	WARN_ON(offset >= sizeof(struct can_device_stats) ||
+		offset % sizeof(unsigned long) != 0);
+
+	read_lock(&dev_base_lock);
+	if (dev_isalive(dev))
+		ret = sprintf(buf, "%ld\n",
+			      *(unsigned long *)(((u8 *)stats) + offset));
+
+	read_unlock(&dev_base_lock);
+	return ret;
+}
+
+/* Generate a read-only CAN statistics attribute */
+#define CAN_STAT_ENTRY(name)						\
+static ssize_t show_##name(struct device *d,				\
+			   struct device_attribute *attr, char *buf) 	\
+{									\
+	return can_stat_show(d, attr, buf,				\
+			     offsetof(struct can_device_stats, name));	\
+}									\
+static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
+
+CAN_STAT_ENTRY(error_warning);
+CAN_STAT_ENTRY(error_passive);
+CAN_STAT_ENTRY(bus_error);
+CAN_STAT_ENTRY(arbitration_lost);
+CAN_STAT_ENTRY(data_overrun);
+CAN_STAT_ENTRY(wakeup);
+CAN_STAT_ENTRY(restarts);
+
+static struct attribute *can_statistics_attrs[] = {
+	&dev_attr_error_warning.attr,
+	&dev_attr_error_passive.attr,
+	&dev_attr_bus_error.attr,
+	&dev_attr_arbitration_lost.attr,
+	&dev_attr_data_overrun.attr,
+	&dev_attr_wakeup.attr,
+	&dev_attr_restarts.attr,
+	NULL
+};
+
+static struct attribute_group can_statistics_group = {
+	.name = "can_statistics",
+	.attrs = can_statistics_attrs,
+};
+
+void can_create_sysfs(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+	int err;
+
+	CAN_CREATE_FILE(dev, can_ctrlmode);
+	CAN_CREATE_FILE(dev, can_echo);
+	CAN_CREATE_FILE(dev, can_restart);
+	CAN_CREATE_FILE(dev, can_state);
+	CAN_CREATE_FILE(dev, can_restart_ms);
+
+	err = sysfs_create_group(&(dev->dev.kobj),
+				 &can_statistics_group);
+	if (err) {
+		printk(KERN_EMERG
+		       "couldn't create sysfs group for CAN statistics\n");
+	}
+
+	if (priv->bittiming_const) {
+		err = sysfs_create_group(&(dev->dev.kobj),
+					 &can_bittiming_group);
+		if (err) {
+			printk(KERN_EMERG "couldn't create sysfs "
+			       "group for CAN bittiming\n");
+		}
+	}
+}
+
+void can_remove_sysfs(struct net_device *dev)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	CAN_REMOVE_FILE(dev, can_ctrlmode);
+	CAN_REMOVE_FILE(dev, can_echo);
+	CAN_REMOVE_FILE(dev, can_state);
+	CAN_REMOVE_FILE(dev, can_restart);
+	CAN_REMOVE_FILE(dev, can_restart_ms);
+
+	sysfs_remove_group(&(dev->dev.kobj), &can_statistics_group);
+	if (priv->bittiming_const)
+		sysfs_remove_group(&(dev->dev.kobj), &can_bittiming_group);
+}
+
+#endif /* CONFIG_SYSFS */
+
+
+
diff --git a/drivers/net/can/sysfs.h b/drivers/net/can/sysfs.h
new file mode 100644
index 0000000..e21f2fa
--- /dev/null
+++ b/drivers/net/can/sysfs.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2007 Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the version 2 of the GNU General Public License
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef CAN_SYSFS_H
+#define CAN_SYSFS_H
+
+void can_create_sysfs(struct net_device *dev);
+void can_remove_sysfs(struct net_device *dev);
+
+#endif /* CAN_SYSFS_H */
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
new file mode 100644
index 0000000..078ac03
--- /dev/null
+++ b/include/linux/can/dev.h
@@ -0,0 +1,136 @@
+/*
+ * linux/can/dev.h
+ *
+ * Definitions for the CAN network device driver interface
+ *
+ * Copyright (C) 2006 Andrey Volkov <avolkov@xxxxxxxxxxxx>
+ *               Varma Electronics Oy
+ *
+ * Copyright (C) 2008 Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
+ *
+ * Send feedback to <socketcan-users@xxxxxxxxxxxxxxxx>
+ */
+
+#ifndef CAN_DEV_H
+#define CAN_DEV_H
+
+#include <linux/can/error.h>
+
+/*
+ * CAN bitrate and bit-timing
+ */
+struct can_bittiming {
+	u32 bitrate;
+	u32 sample_point;
+	u32 tq;
+	u32 prop_seg;
+	u32 phase_seg1;
+	u32 phase_seg2;
+	u32 sjw;
+	u32 clock;
+	u32 brp;
+};
+
+struct can_bittiming_const {
+	u32 tseg1_min;
+	u32 tseg1_max;
+	u32 tseg2_min;
+	u32 tseg2_max;
+	u32 sjw_max;
+	u32 brp_min;
+	u32 brp_max;
+	u32 brp_inc;
+};
+
+/*
+ * CAN mode
+ */
+enum can_mode {
+	CAN_MODE_STOP = 0,
+	CAN_MODE_START,
+	CAN_MODE_SLEEP
+};
+
+/*
+ * CAN controller mode
+ */
+#define CAN_CTRLMODE_LOOPBACK	0x1
+#define CAN_CTRLMODE_LISTENONLY	0x2
+#define CAN_CTRLMODE_3_SAMPLES	0x4 /* Triple sampling mode */
+
+/*
+ * CAN operational and error states
+ */
+enum can_state {
+	CAN_STATE_ACTIVE = 0,
+	CAN_STATE_BUS_WARNING,
+	CAN_STATE_BUS_PASSIVE,
+	CAN_STATE_BUS_OFF,
+	CAN_STATE_STOPPED,
+	CAN_STATE_SLEEPING
+};
+
+/*
+ * CAN device statistics
+ */
+struct can_device_stats {
+	unsigned long error_warning;
+	unsigned long data_overrun;
+	unsigned long wakeup;
+	unsigned long bus_error;
+	unsigned long error_passive;
+	unsigned long arbitration_lost;
+	unsigned long restarts;
+	unsigned long bus_error_at_init;
+};
+
+/*
+ * CAN common private data
+ */
+#define CAN_ECHO_SKB_MAX  4
+
+struct can_priv {
+	struct can_device_stats can_stats;
+
+	struct can_bittiming bittiming;
+	struct can_bittiming_const *bittiming_const;
+
+	spinlock_t irq_lock;
+
+	enum can_state state;
+	u32 ctrlmode;
+
+	int restart_ms;
+	struct timer_list timer;
+
+	struct sk_buff *echo_skb[CAN_ECHO_SKB_MAX];
+
+	int (*do_set_bittiming)(struct net_device *dev);
+	int (*do_get_state)(struct net_device *dev, enum can_state *state);
+	int (*do_set_mode)(struct net_device *dev, enum can_mode mode);
+	int (*do_set_ctrlmode)(struct net_device *dev, u32 ctrlmode);
+	int (*do_get_ctrlmode)(struct net_device *dev, u32 *ctrlmode);
+};
+
+#define ND2D(_ndev)	(_ndev->dev.parent)
+
+
+struct net_device *alloc_candev(int sizeof_priv);
+void free_candev(struct net_device *dev);
+int register_candev(struct net_device *dev);
+void unregister_candev(struct net_device *dev);
+
+int can_set_bittiming(struct net_device *dev);
+
+int can_restart_now(struct net_device *dev);
+
+void can_bus_off(struct net_device *dev);
+
+void can_close_cleanup(struct net_device *dev);
+
+void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx);
+void can_get_echo_skb(struct net_device *dev, int idx);
+
+int can_sample_point(struct can_bittiming *bt);
+
+#endif /* CAN_DEV_H */
-- 
1.5.6.6

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