Merge branch 'for-davem' of git://gitorious.org/linux-can/linux-can-next

Marc Kleine-Budde says:

====================
the fifth pull request for upcoming v3.6 net-next cleans up and
improves the janz-ican3 driver (6 patches by Ira W. Snyder, one by me).
A patch by Steffen Trumtrar adds imx53 support to the flexcan driver.
And another patch by me, which marks the bit timing constant in the CAN
drivers as "const".
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

15 files changed, 226 insertions, 88 deletions

diff --git a/drivers/net/can/at91_can.c b/drivers/net/can/at91_can.c
index 6ea905c2cf6d..fcff73a73b1d 100644
--- a/drivers/net/can/at91_can.c
+++ b/drivers/net/can/at91_can.c
@@ -170,7 +170,7 @@ static const struct at91_devtype_data at91_devtype_data[] __devinitconst = {
 	},
 };
 
-static struct can_bittiming_const at91_bittiming_const = {
+static const struct can_bittiming_const at91_bittiming_const = {
 	.name		= KBUILD_MODNAME,
 	.tseg1_min	= 4,
 	.tseg1_max	= 16,
diff --git a/drivers/net/can/bfin_can.c b/drivers/net/can/bfin_can.c
index ea3143895e6d..f2d6d258a286 100644
--- a/drivers/net/can/bfin_can.c
+++ b/drivers/net/can/bfin_can.c
@@ -44,7 +44,7 @@ struct bfin_can_priv {
 /*
  * bfin can timing parameters
  */
-static struct can_bittiming_const bfin_can_bittiming_const = {
+static const struct can_bittiming_const bfin_can_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index eea660800a09..4c538e388655 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -189,7 +189,7 @@ enum c_can_bus_error_types {
 	C_CAN_ERROR_PASSIVE,
 };
 
-static struct can_bittiming_const c_can_bittiming_const = {
+static const struct can_bittiming_const c_can_bittiming_const = {
 	.name = KBUILD_MODNAME,
 	.tseg1_min = 2,		/* Time segment 1 = prop_seg + phase_seg1 */
 	.tseg1_max = 16,
diff --git a/drivers/net/can/cc770/cc770.c b/drivers/net/can/cc770/cc770.c
index a138db11cbf0..0f12abf6591c 100644
--- a/drivers/net/can/cc770/cc770.c
+++ b/drivers/net/can/cc770/cc770.c
@@ -90,7 +90,7 @@ static unsigned char cc770_obj_flags[CC770_OBJ_MAX] = {
 	[CC770_OBJ_TX] = 0,
 };
 
-static struct can_bittiming_const cc770_bittiming_const = {
+static const struct can_bittiming_const cc770_bittiming_const = {
 	.name = KBUILD_MODNAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 1b6f5621ce89..c5f143165f80 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -190,7 +190,8 @@ struct flexcan_priv {
 	u32 reg_esr;
 	u32 reg_ctrl_default;
 
-	struct clk *clk;
+	struct clk *clk_ipg;
+	struct clk *clk_per;
 	struct flexcan_platform_data *pdata;
 	const struct flexcan_devtype_data *devtype_data;
 };
@@ -203,7 +204,7 @@ static struct flexcan_devtype_data fsl_imx6q_devtype_data = {
 	.hw_ver = 10,
 };
 
-static struct can_bittiming_const flexcan_bittiming_const = {
+static const struct can_bittiming_const flexcan_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 4,
 	.tseg1_max = 16,
@@ -828,7 +829,8 @@ static int flexcan_open(struct net_device *dev)
 	struct flexcan_priv *priv = netdev_priv(dev);
 	int err;
 
-	clk_prepare_enable(priv->clk);
+	clk_prepare_enable(priv->clk_ipg);
+	clk_prepare_enable(priv->clk_per);
 
 	err = open_candev(dev);
 	if (err)
@@ -850,7 +852,8 @@ static int flexcan_open(struct net_device *dev)
  out_close:
 	close_candev(dev);
  out:
-	clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk_per);
+	clk_disable_unprepare(priv->clk_ipg);
 
 	return err;
 }
@@ -864,7 +867,8 @@ static int flexcan_close(struct net_device *dev)
 	flexcan_chip_stop(dev);
 
 	free_irq(dev->irq, dev);
-	clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk_per);
+	clk_disable_unprepare(priv->clk_ipg);
 
 	close_candev(dev);
 
@@ -903,7 +907,8 @@ static int __devinit register_flexcandev(struct net_device *dev)
 	struct flexcan_regs __iomem *regs = priv->base;
 	u32 reg, err;
 
-	clk_prepare_enable(priv->clk);
+	clk_prepare_enable(priv->clk_ipg);
+	clk_prepare_enable(priv->clk_per);
 
 	/* select "bus clock", chip must be disabled */
 	flexcan_chip_disable(priv);
@@ -936,7 +941,8 @@ static int __devinit register_flexcandev(struct net_device *dev)
  out:
 	/* disable core and turn off clocks */
 	flexcan_chip_disable(priv);
-	clk_disable_unprepare(priv->clk);
+	clk_disable_unprepare(priv->clk_per);
+	clk_disable_unprepare(priv->clk_ipg);
 
 	return err;
 }
@@ -964,7 +970,7 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
 	struct net_device *dev;
 	struct flexcan_priv *priv;
 	struct resource *mem;
-	struct clk *clk = NULL;
+	struct clk *clk_ipg = NULL, *clk_per = NULL;
 	struct pinctrl *pinctrl;
 	void __iomem *base;
 	resource_size_t mem_size;
@@ -980,13 +986,20 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
 						"clock-frequency", &clock_freq);
 
 	if (!clock_freq) {
-		clk = clk_get(&pdev->dev, NULL);
-		if (IS_ERR(clk)) {
-			dev_err(&pdev->dev, "no clock defined\n");
-			err = PTR_ERR(clk);
+		clk_ipg = devm_clk_get(&pdev->dev, "ipg");
+		if (IS_ERR(clk_ipg)) {
+			dev_err(&pdev->dev, "no ipg clock defined\n");
+			err = PTR_ERR(clk_ipg);
+			goto failed_clock;
+		}
+		clock_freq = clk_get_rate(clk_ipg);
+
+		clk_per = devm_clk_get(&pdev->dev, "per");
+		if (IS_ERR(clk_per)) {
+			dev_err(&pdev->dev, "no per clock defined\n");
+			err = PTR_ERR(clk_per);
 			goto failed_clock;
 		}
-		clock_freq = clk_get_rate(clk);
 	}
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -1039,7 +1052,8 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
 		CAN_CTRLMODE_BERR_REPORTING;
 	priv->base = base;
 	priv->dev = dev;
-	priv->clk = clk;
+	priv->clk_ipg = clk_ipg;
+	priv->clk_per = clk_per;
 	priv->pdata = pdev->dev.platform_data;
 	priv->devtype_data = devtype_data;
 
@@ -1067,8 +1081,6 @@ static int __devinit flexcan_probe(struct platform_device *pdev)
  failed_map:
 	release_mem_region(mem->start, mem_size);
  failed_get:
-	if (clk)
-		clk_put(clk);
  failed_clock:
 	return err;
 }
@@ -1086,9 +1098,6 @@ static int __devexit flexcan_remove(struct platform_device *pdev)
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	release_mem_region(mem->start, resource_size(mem));
 
-	if (priv->clk)
-		clk_put(priv->clk);
-
 	free_candev(dev);
 
 	return 0;
diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c
index 08c893cb7896..98ee43819911 100644
--- a/drivers/net/can/janz-ican3.c
+++ b/drivers/net/can/janz-ican3.c
@@ -116,6 +116,7 @@
 #define ICAN3_BUSERR_QUOTA_MAX	255
 
 /* Janz ICAN3 CAN Frame Conversion */
+#define ICAN3_SNGL	0x02
 #define ICAN3_ECHO	0x10
 #define ICAN3_EFF_RTR	0x40
 #define ICAN3_SFF_RTR	0x10
@@ -220,6 +221,9 @@ struct ican3_dev {
 	/* old and new style host interface */
 	unsigned int iftype;
 
+	/* queue for echo packets */
+	struct sk_buff_head echoq;
+
 	/*
 	 * Any function which changes the current DPM page must hold this
 	 * lock while it is performing data accesses. This ensures that the
@@ -235,7 +239,6 @@ struct ican3_dev {
 
 	/* fast host interface */
 	unsigned int fastrx_start;
-	unsigned int fastrx_int;
 	unsigned int fastrx_num;
 	unsigned int fasttx_start;
 	unsigned int fasttx_num;
@@ -454,7 +457,6 @@ static void __devinit ican3_init_fast_host_interface(struct ican3_dev *mod)
 	/* save the start recv page */
 	mod->fastrx_start = mod->free_page;
 	mod->fastrx_num = 0;
-	mod->fastrx_int = 0;
 
 	/* build a single fast tohost queue descriptor */
 	memset(&desc, 0, sizeof(desc));
@@ -813,10 +815,10 @@ static void ican3_to_can_frame(struct ican3_dev *mod,
 
 		cf->can_id |= desc->data[0] << 3;
 		cf->can_id |= (desc->data[1] & 0xe0) >> 5;
-		cf->can_dlc = desc->data[1] & ICAN3_CAN_DLC_MASK;
-		memcpy(cf->data, &desc->data[2], sizeof(cf->data));
+		cf->can_dlc = get_can_dlc(desc->data[1] & ICAN3_CAN_DLC_MASK);
+		memcpy(cf->data, &desc->data[2], cf->can_dlc);
 	} else {
-		cf->can_dlc = desc->data[0] & ICAN3_CAN_DLC_MASK;
+		cf->can_dlc = get_can_dlc(desc->data[0] & ICAN3_CAN_DLC_MASK);
 		if (desc->data[0] & ICAN3_EFF_RTR)
 			cf->can_id |= CAN_RTR_FLAG;
 
@@ -831,7 +833,7 @@ static void ican3_to_can_frame(struct ican3_dev *mod,
 			cf->can_id |= desc->data[3] >> 5;  /* 2-0   */
 		}
 
-		memcpy(cf->data, &desc->data[6], sizeof(cf->data));
+		memcpy(cf->data, &desc->data[6], cf->can_dlc);
 	}
 }
 
@@ -847,6 +849,10 @@ static void can_frame_to_ican3(struct ican3_dev *mod,
 	desc->data[0] |= cf->can_dlc;
 	desc->data[1] |= ICAN3_ECHO;
 
+	/* support single transmission (no retries) mode */
+	if (mod->can.ctrlmode & CAN_CTRLMODE_ONE_SHOT)
+		desc->data[1] |= ICAN3_SNGL;
+
 	if (cf->can_id & CAN_RTR_FLAG)
 		desc->data[0] |= ICAN3_EFF_RTR;
 
@@ -863,7 +869,7 @@ static void can_frame_to_ican3(struct ican3_dev *mod,
 	}
 
 	/* copy the data bits into the descriptor */
-	memcpy(&desc->data[6], cf->data, sizeof(cf->data));
+	memcpy(&desc->data[6], cf->data, cf->can_dlc);
 }
 
 /*
@@ -909,8 +915,8 @@ static void ican3_handle_msglost(struct ican3_dev *mod, struct ican3_msg *msg)
 	if (skb) {
 		cf->can_id |= CAN_ERR_CRTL;
 		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		stats->rx_over_errors++;
 		stats->rx_errors++;
-		stats->rx_bytes += cf->can_dlc;
 		netif_rx(skb);
 	}
 }
@@ -927,7 +933,7 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
 	struct net_device *dev = mod->ndev;
 	struct net_device_stats *stats = &dev->stats;
 	enum can_state state = mod->can.state;
-	u8 status, isrc, rxerr, txerr;
+	u8 isrc, ecc, status, rxerr, txerr;
 	struct can_frame *cf;
 	struct sk_buff *skb;
 
@@ -943,15 +949,53 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
 		return -EINVAL;
 	}
 
-	skb = alloc_can_err_skb(dev, &cf);
-	if (skb == NULL)
-		return -ENOMEM;
-
 	isrc = msg->data[0];
+	ecc = msg->data[2];
 	status = msg->data[3];
 	rxerr = msg->data[4];
 	txerr = msg->data[5];
 
+	/*
+	 * This hardware lacks any support other than bus error messages to
+	 * determine if packet transmission has failed.
+	 *
+	 * When TX errors happen, one echo skb needs to be dropped from the
+	 * front of the queue.
+	 *
+	 * A small bit of code is duplicated here and below, to avoid error
+	 * skb allocation when it will just be freed immediately.
+	 */
+	if (isrc == CEVTIND_BEI) {
+		int ret;
+		dev_dbg(mod->dev, "bus error interrupt\n");
+
+		/* TX error */
+		if (!(ecc & ECC_DIR)) {
+			kfree_skb(skb_dequeue(&mod->echoq));
+			stats->tx_errors++;
+		} else {
+			stats->rx_errors++;
+		}
+
+		/*
+		 * The controller automatically disables bus-error interrupts
+		 * and therefore we must re-enable them.
+		 */
+		ret = ican3_set_buserror(mod, 1);
+		if (ret) {
+			dev_err(mod->dev, "unable to re-enable bus-error\n");
+			return ret;
+		}
+
+		/* bus error reporting is off, return immediately */
+		if (!(mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING))
+			return 0;
+	}
+
+	skb = alloc_can_err_skb(dev, &cf);
+	if (skb == NULL)
+		return -ENOMEM;
+
 	/* data overrun interrupt */
 	if (isrc == CEVTIND_DOI || isrc == CEVTIND_LOST) {
 		dev_dbg(mod->dev, "data overrun interrupt\n");
@@ -980,11 +1024,7 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
 
 	/* bus error interrupt */
 	if (isrc == CEVTIND_BEI) {
-		u8 ecc = msg->data[2];
-
-		dev_dbg(mod->dev, "bus error interrupt\n");
 		mod->can.can_stats.bus_error++;
-		stats->rx_errors++;
 		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
 
 		switch (ecc & ECC_MASK) {
@@ -1003,7 +1043,7 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
 			break;
 		}
 
-		if ((ecc & ECC_DIR) == 0)
+		if (!(ecc & ECC_DIR))
 			cf->data[2] |= CAN_ERR_PROT_TX;
 
 		cf->data[6] = txerr;
@@ -1030,8 +1070,6 @@ static int ican3_handle_cevtind(struct ican3_dev *mod, struct ican3_msg *msg)
 	}
 
 	mod->can.state = state;
-	stats->rx_errors++;
-	stats->rx_bytes += cf->can_dlc;
 	netif_rx(skb);
 	return 0;
 }
@@ -1091,6 +1129,88 @@ static void ican3_handle_message(struct ican3_dev *mod, struct ican3_msg *msg)
 }
 
 /*
+ * The ican3 needs to store all echo skbs, and therefore cannot
+ * use the generic infrastructure for this.
+ */
+static void ican3_put_echo_skb(struct ican3_dev *mod, struct sk_buff *skb)
+{
+	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;
+
+	/* save this skb for tx interrupt echo handling */
+	skb_queue_tail(&mod->echoq, skb);
+}
+
+static unsigned int ican3_get_echo_skb(struct ican3_dev *mod)
+{
+	struct sk_buff *skb = skb_dequeue(&mod->echoq);
+	struct can_frame *cf;
+	u8 dlc;
+
+	/* this should never trigger unless there is a driver bug */
+	if (!skb) {
+		netdev_err(mod->ndev, "BUG: echo skb not occupied\n");
+		return 0;
+	}
+
+	cf = (struct can_frame *)skb->data;
+	dlc = cf->can_dlc;
+
+	/* check flag whether this packet has to be looped back */
+	if (skb->pkt_type != PACKET_LOOPBACK) {
+		kfree_skb(skb);
+		return dlc;
+	}
+
+	skb->protocol = htons(ETH_P_CAN);
+	skb->pkt_type = PACKET_BROADCAST;
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	skb->dev = mod->ndev;
+	netif_receive_skb(skb);
+	return dlc;
+}
+
+/*
+ * Compare an skb with an existing echo skb
+ *
+ * This function will be used on devices which have a hardware loopback.
+ * On these devices, this function can be used to compare a received skb
+ * with the saved echo skbs so that the hardware echo skb can be dropped.
+ *
+ * Returns true if the skb's are identical, false otherwise.
+ */
+static bool ican3_echo_skb_matches(struct ican3_dev *mod, struct sk_buff *skb)
+{
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	struct sk_buff *echo_skb = skb_peek(&mod->echoq);
+	struct can_frame *echo_cf;
+
+	if (!echo_skb)
+		return false;
+
+	echo_cf = (struct can_frame *)echo_skb->data;
+	if (cf->can_id != echo_cf->can_id)
+		return false;
+
+	if (cf->can_dlc != echo_cf->can_dlc)
+		return false;
+
+	return memcmp(cf->data, echo_cf->data, cf->can_dlc) == 0;
+}
+
+/*
  * Check that there is room in the TX ring to transmit another skb
  *
  * LOCKING: must hold mod->lock
@@ -1100,6 +1220,10 @@ static bool ican3_txok(struct ican3_dev *mod)
 	struct ican3_fast_desc __iomem *desc;
 	u8 control;
 
+	/* check that we have echo queue space */
+	if (skb_queue_len(&mod->echoq) >= ICAN3_TX_BUFFERS)
+		return false;
+
 	/* copy the control bits of the descriptor */
 	ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16));
 	desc = mod->dpm + ((mod->fasttx_num % 16) * sizeof(*desc));
@@ -1150,10 +1274,27 @@ static int ican3_recv_skb(struct ican3_dev *mod)
 	/* convert the ICAN3 frame into Linux CAN format */
 	ican3_to_can_frame(mod, &desc, cf);
 
-	/* receive the skb, update statistics */
-	netif_receive_skb(skb);
+	/*
+	 * If this is an ECHO frame received from the hardware loopback
+	 * feature, use the skb saved in the ECHO stack instead. This allows
+	 * the Linux CAN core to support CAN_RAW_RECV_OWN_MSGS correctly.
+	 *
+	 * Since this is a confirmation of a successfully transmitted packet
+	 * sent from this host, update the transmit statistics.
+	 *
+	 * Also, the netdevice queue needs to be allowed to send packets again.
+	 */
+	if (ican3_echo_skb_matches(mod, skb)) {
+		stats->tx_packets++;
+		stats->tx_bytes += ican3_get_echo_skb(mod);
+		kfree_skb(skb);
+		goto err_noalloc;
+	}
+
+	/* update statistics, receive the skb */
 	stats->rx_packets++;
 	stats->rx_bytes += cf->can_dlc;
+	netif_receive_skb(skb);
 
 err_noalloc:
 	/* toggle the valid bit and return the descriptor to the ring */
@@ -1176,13 +1317,13 @@ err_noalloc:
 static int ican3_napi(struct napi_struct *napi, int budget)
 {
 	struct ican3_dev *mod = container_of(napi, struct ican3_dev, napi);
-	struct ican3_msg msg;
 	unsigned long flags;
 	int received = 0;
 	int ret;
 
 	/* process all communication messages */
 	while (true) {
+		struct ican3_msg msg;
 		ret = ican3_recv_msg(mod, &msg);
 		if (ret)
 			break;
@@ -1325,7 +1466,7 @@ static int __devinit ican3_startup_module(struct ican3_dev *mod)
 	}
 
 	/* default to "bus errors enabled" */
-	ret = ican3_set_buserror(mod, ICAN3_BUSERR_QUOTA_MAX);
+	ret = ican3_set_buserror(mod, 1);
 	if (ret) {
 		dev_err(mod->dev, "unable to set bus-error\n");
 		return ret;
@@ -1354,7 +1495,6 @@ static int __devinit ican3_startup_module(struct ican3_dev *mod)
 static int ican3_open(struct net_device *ndev)
 {
 	struct ican3_dev *mod = netdev_priv(ndev);
-	u8 quota;
 	int ret;
 
 	/* open the CAN layer */
@@ -1364,19 +1504,6 @@ static int ican3_open(struct net_device *ndev)
 		return ret;
 	}
 
-	/* set the bus error generation state appropriately */
-	if (mod->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
-		quota = ICAN3_BUSERR_QUOTA_MAX;
-	else
-		quota = 0;
-
-	ret = ican3_set_buserror(mod, quota);
-	if (ret) {
-		dev_err(mod->dev, "unable to set bus-error\n");
-		close_candev(ndev);
-		return ret;
-	}
-
 	/* bring the bus online */
 	ret = ican3_set_bus_state(mod, true);
 	if (ret) {
@@ -1408,6 +1535,9 @@ static int ican3_stop(struct net_device *ndev)
 		return ret;
 	}
 
+	/* drop all outstanding echo skbs */
+	skb_queue_purge(&mod->echoq);
+
 	/* close the CAN layer */
 	close_candev(ndev);
 	return 0;
@@ -1416,18 +1546,19 @@ static int ican3_stop(struct net_device *ndev)
 static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
 {
 	struct ican3_dev *mod = netdev_priv(ndev);
-	struct net_device_stats *stats = &ndev->stats;
 	struct can_frame *cf = (struct can_frame *)skb->data;
 	struct ican3_fast_desc desc;
 	void __iomem *desc_addr;
 	unsigned long flags;
 
+	if (can_dropped_invalid_skb(ndev, skb))
+		return NETDEV_TX_OK;
+
 	spin_lock_irqsave(&mod->lock, flags);
 
 	/* check that we can actually transmit */
 	if (!ican3_txok(mod)) {
-		dev_err(mod->dev, "no free descriptors, stopping queue\n");
-		netif_stop_queue(ndev);
+		dev_err(mod->dev, "BUG: no free descriptors\n");
 		spin_unlock_irqrestore(&mod->lock, flags);
 		return NETDEV_TX_BUSY;
 	}
@@ -1442,6 +1573,14 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
 	can_frame_to_ican3(mod, cf, &desc);
 
 	/*
+	 * This hardware doesn't have TX-done notifications, so we'll try and
+	 * emulate it the best we can using ECHO skbs. Add the skb to the ECHO
+	 * stack. Upon packet reception, check if the ECHO skb and received
+	 * skb match, and use that to wake the queue.
+	 */
+	ican3_put_echo_skb(mod, skb);
+
+	/*
 	 * the programming manual says that you must set the IVALID bit, then
 	 * interrupt, then set the valid bit. Quite weird, but it seems to be
 	 * required for this to work
@@ -1459,19 +1598,7 @@ static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
 	mod->fasttx_num = (desc.control & DESC_WRAP) ? 0
 						     : (mod->fasttx_num + 1);
 
-	/* update statistics */
-	stats->tx_packets++;
-	stats->tx_bytes += cf->can_dlc;
-	kfree_skb(skb);
-
-	/*
-	 * This hardware doesn't have TX-done notifications, so we'll try and
-	 * emulate it the best we can using ECHO skbs. Get the next TX
-	 * descriptor, and see if we have room to send. If not, stop the queue.
-	 * It will be woken when the ECHO skb for the current packet is recv'd.
-	 */
-
-	/* copy the control bits of the descriptor */
+	/* if there is no free descriptor space, stop the transmit queue */
 	if (!ican3_txok(mod))
 		netif_stop_queue(ndev);
 
@@ -1490,7 +1617,7 @@ static const struct net_device_ops ican3_netdev_ops = {
  */
 
 /* This structure was stolen from drivers/net/can/sja1000/sja1000.c */
-static struct can_bittiming_const ican3_bittiming_const = {
+static const struct can_bittiming_const ican3_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
@@ -1667,6 +1794,7 @@ static int __devinit ican3_probe(struct platform_device *pdev)
 	mod->dev = &pdev->dev;
 	mod->num = pdata->modno;
 	netif_napi_add(ndev, &mod->napi, ican3_napi, ICAN3_RX_BUFFERS);
+	skb_queue_head_init(&mod->echoq);
 	spin_lock_init(&mod->lock);
 	init_completion(&mod->termination_comp);
 	init_completion(&mod->buserror_comp);
@@ -1687,7 +1815,8 @@ static int __devinit ican3_probe(struct platform_device *pdev)
 	mod->can.do_set_mode = ican3_set_mode;
 	mod->can.do_get_berr_counter = ican3_get_berr_counter;
 	mod->can.ctrlmode_supported = CAN_CTRLMODE_3_SAMPLES
-				    | CAN_CTRLMODE_BERR_REPORTING;
+				    | CAN_CTRLMODE_BERR_REPORTING
+				    | CAN_CTRLMODE_ONE_SHOT;
 
 	/* find our IRQ number */
 	mod->irq = platform_get_irq(pdev, 0);
diff --git a/drivers/net/can/mcp251x.c b/drivers/net/can/mcp251x.c
index 9120a36ec702..a580db29e503 100644
--- a/drivers/net/can/mcp251x.c
+++ b/drivers/net/can/mcp251x.c
@@ -214,7 +214,7 @@ static int mcp251x_enable_dma; /* Enable SPI DMA. Default: 0 (Off) */
 module_param(mcp251x_enable_dma, int, S_IRUGO);
 MODULE_PARM_DESC(mcp251x_enable_dma, "Enable SPI DMA. Default: 0 (Off)");
 
-static struct can_bittiming_const mcp251x_bittiming_const = {
+static const struct can_bittiming_const mcp251x_bittiming_const = {
 	.name = DEVICE_NAME,
 	.tseg1_min = 3,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/mscan/mscan.c b/drivers/net/can/mscan/mscan.c
index 41a2a2dda7ea..2b104d5f422c 100644
--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -34,7 +34,7 @@
 
 #include "mscan.h"
 
-static struct can_bittiming_const mscan_bittiming_const = {
+static const struct can_bittiming_const mscan_bittiming_const = {
 	.name = "mscan",
 	.tseg1_min = 4,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/pch_can.c b/drivers/net/can/pch_can.c
index 1226297e7676..48b3d62b34cb 100644
--- a/drivers/net/can/pch_can.c
+++ b/drivers/net/can/pch_can.c
@@ -184,7 +184,7 @@ struct pch_can_priv {
 	int use_msi;
 };
 
-static struct can_bittiming_const pch_can_bittiming_const = {
+static const struct can_bittiming_const pch_can_bittiming_const = {
 	.name = KBUILD_MODNAME,
 	.tseg1_min = 2,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/sja1000/sja1000.c b/drivers/net/can/sja1000/sja1000.c
index 5e10472371ed..4c4f33d482d2 100644
--- a/drivers/net/can/sja1000/sja1000.c
+++ b/drivers/net/can/sja1000/sja1000.c
@@ -69,7 +69,7 @@ MODULE_AUTHOR("Oliver Hartkopp <oliver.hartkopp@volkswagen.de>");
 MODULE_LICENSE("Dual BSD/GPL");
 MODULE_DESCRIPTION(DRV_NAME "CAN netdevice driver");
 
-static struct can_bittiming_const sja1000_bittiming_const = {
+static const struct can_bittiming_const sja1000_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/ti_hecc.c b/drivers/net/can/ti_hecc.c
index 4accd7ec6954..527dbcf95335 100644
--- a/drivers/net/can/ti_hecc.c
+++ b/drivers/net/can/ti_hecc.c
@@ -196,7 +196,7 @@ MODULE_VERSION(HECC_MODULE_VERSION);
 #define HECC_CANGIM_SIL		BIT(2)	/* system interrupts to int line 1 */
 
 /* CAN Bittiming constants as per HECC specs */
-static struct can_bittiming_const ti_hecc_bittiming_const = {
+static const struct can_bittiming_const ti_hecc_bittiming_const = {
 	.name = DRV_NAME,
 	.tseg1_min = 1,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/usb/ems_usb.c b/drivers/net/can/usb/ems_usb.c
index 7ae65fc80032..086fa321677a 100644
--- a/drivers/net/can/usb/ems_usb.c
+++ b/drivers/net/can/usb/ems_usb.c
@@ -889,7 +889,7 @@ static const struct net_device_ops ems_usb_netdev_ops = {
 	.ndo_start_xmit = ems_usb_start_xmit,
 };
 
-static struct can_bittiming_const ems_usb_bittiming_const = {
+static const struct can_bittiming_const ems_usb_bittiming_const = {
 	.name = "ems_usb",
 	.tseg1_min = 1,
 	.tseg1_max = 16,
diff --git a/drivers/net/can/usb/esd_usb2.c b/drivers/net/can/usb/esd_usb2.c
index 09b1da5bc512..bd36e5517173 100644
--- a/drivers/net/can/usb/esd_usb2.c
+++ b/drivers/net/can/usb/esd_usb2.c
@@ -871,7 +871,7 @@ static const struct net_device_ops esd_usb2_netdev_ops = {
 	.ndo_start_xmit = esd_usb2_start_xmit,
 };
 
-static struct can_bittiming_const esd_usb2_bittiming_const = {
+static const struct can_bittiming_const esd_usb2_bittiming_const = {
 	.name = "esd_usb2",
 	.tseg1_min = ESD_USB2_TSEG1_MIN,
 	.tseg1_max = ESD_USB2_TSEG1_MAX,
diff --git a/drivers/net/can/usb/peak_usb/pcan_usb_core.h b/drivers/net/can/usb/peak_usb/pcan_usb_core.h
index a948c5a89401..4c775b620be2 100644
--- a/drivers/net/can/usb/peak_usb/pcan_usb_core.h
+++ b/drivers/net/can/usb/peak_usb/pcan_usb_core.h
@@ -45,7 +45,7 @@ struct peak_usb_adapter {
 	char *name;
 	u32 device_id;
 	struct can_clock clock;
-	struct can_bittiming_const bittiming_const;
+	const struct can_bittiming_const bittiming_const;
 	unsigned int ctrl_count;
 
 	int (*intf_probe)(struct usb_interface *intf);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index ee5a771fb20d..2b2fc345afca 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -33,7 +33,7 @@ struct can_priv {
 	struct can_device_stats can_stats;
 
 	struct can_bittiming bittiming;
-	struct can_bittiming_const *bittiming_const;
+	const struct can_bittiming_const *bittiming_const;
 	struct can_clock clock;
 
 	enum can_state state;