Initial import

1 files changed, 1922 insertions, 0 deletions

diff --git a/drivers/net/can/janz-ican3.c b/drivers/net/can/janz-ican3.c
new file mode 100644
index 000000000..4dd183a36
--- /dev/null
+++ b/drivers/net/can/janz-ican3.c
@@ -0,0 +1,1922 @@
+/*
+ * Janz MODULbus VMOD-ICAN3 CAN Interface Driver
+ *
+ * Copyright (c) 2010 Ira W. Snyder <iws@ovro.caltech.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+
+#include <linux/netdevice.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/skb.h>
+#include <linux/can/error.h>
+
+#include <linux/mfd/janz.h>
+#include <asm/io.h>
+
+/* the DPM has 64k of memory, organized into 256x 256 byte pages */
+#define DPM_NUM_PAGES		256
+#define DPM_PAGE_SIZE		256
+#define DPM_PAGE_ADDR(p)	((p) * DPM_PAGE_SIZE)
+
+/* JANZ ICAN3 "old-style" host interface queue page numbers */
+#define QUEUE_OLD_CONTROL	0
+#define QUEUE_OLD_RB0		1
+#define QUEUE_OLD_RB1		2
+#define QUEUE_OLD_WB0		3
+#define QUEUE_OLD_WB1		4
+
+/* Janz ICAN3 "old-style" host interface control registers */
+#define MSYNC_PEER		0x00		/* ICAN only */
+#define MSYNC_LOCL		0x01		/* host only */
+#define TARGET_RUNNING		0x02
+
+#define MSYNC_RB0		0x01
+#define MSYNC_RB1		0x02
+#define MSYNC_RBLW		0x04
+#define MSYNC_RB_MASK		(MSYNC_RB0 | MSYNC_RB1)
+
+#define MSYNC_WB0		0x10
+#define MSYNC_WB1		0x20
+#define MSYNC_WBLW		0x40
+#define MSYNC_WB_MASK		(MSYNC_WB0 | MSYNC_WB1)
+
+/* Janz ICAN3 "new-style" host interface queue page numbers */
+#define QUEUE_TOHOST		5
+#define QUEUE_FROMHOST_MID	6
+#define QUEUE_FROMHOST_HIGH	7
+#define QUEUE_FROMHOST_LOW	8
+
+/* The first free page in the DPM is #9 */
+#define DPM_FREE_START		9
+
+/* Janz ICAN3 "new-style" and "fast" host interface descriptor flags */
+#define DESC_VALID		0x80
+#define DESC_WRAP		0x40
+#define DESC_INTERRUPT		0x20
+#define DESC_IVALID		0x10
+#define DESC_LEN(len)		(len)
+
+/* Janz ICAN3 Firmware Messages */
+#define MSG_CONNECTI		0x02
+#define MSG_DISCONNECT		0x03
+#define MSG_IDVERS		0x04
+#define MSG_MSGLOST		0x05
+#define MSG_NEWHOSTIF		0x08
+#define MSG_INQUIRY		0x0a
+#define MSG_SETAFILMASK		0x10
+#define MSG_INITFDPMQUEUE	0x11
+#define MSG_HWCONF		0x12
+#define MSG_FMSGLOST		0x15
+#define MSG_CEVTIND		0x37
+#define MSG_CBTRREQ		0x41
+#define MSG_COFFREQ		0x42
+#define MSG_CONREQ		0x43
+#define MSG_CCONFREQ		0x47
+
+/*
+ * Janz ICAN3 CAN Inquiry Message Types
+ *
+ * NOTE: there appears to be a firmware bug here. You must send
+ * NOTE: INQUIRY_STATUS and expect to receive an INQUIRY_EXTENDED
+ * NOTE: response. The controller never responds to a message with
+ * NOTE: the INQUIRY_EXTENDED subspec :(
+ */
+#define INQUIRY_STATUS		0x00
+#define INQUIRY_TERMINATION	0x01
+#define INQUIRY_EXTENDED	0x04
+
+/* Janz ICAN3 CAN Set Acceptance Filter Mask Message Types */
+#define SETAFILMASK_REJECT	0x00
+#define SETAFILMASK_FASTIF	0x02
+
+/* Janz ICAN3 CAN Hardware Configuration Message Types */
+#define HWCONF_TERMINATE_ON	0x01
+#define HWCONF_TERMINATE_OFF	0x00
+
+/* Janz ICAN3 CAN Event Indication Message Types */
+#define CEVTIND_EI		0x01
+#define CEVTIND_DOI		0x02
+#define CEVTIND_LOST		0x04
+#define CEVTIND_FULL		0x08
+#define CEVTIND_BEI		0x10
+
+#define CEVTIND_CHIP_SJA1000	0x02
+
+#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
+#define ICAN3_EFF	0x80
+
+#define ICAN3_CAN_TYPE_MASK	0x0f
+#define ICAN3_CAN_TYPE_SFF	0x00
+#define ICAN3_CAN_TYPE_EFF	0x01
+
+#define ICAN3_CAN_DLC_MASK	0x0f
+
+/*
+ * SJA1000 Status and Error Register Definitions
+ *
+ * Copied from drivers/net/can/sja1000/sja1000.h
+ */
+
+/* status register content */
+#define SR_BS		0x80
+#define SR_ES		0x40
+#define SR_TS		0x20
+#define SR_RS		0x10
+#define SR_TCS		0x08
+#define SR_TBS		0x04
+#define SR_DOS		0x02
+#define SR_RBS		0x01
+
+#define SR_CRIT (SR_BS|SR_ES)
+
+/* ECC register */
+#define ECC_SEG		0x1F
+#define ECC_DIR		0x20
+#define ECC_ERR		6
+#define ECC_BIT		0x00
+#define ECC_FORM	0x40
+#define ECC_STUFF	0x80
+#define ECC_MASK	0xc0
+
+/* Number of buffers for use in the "new-style" host interface */
+#define ICAN3_NEW_BUFFERS	16
+
+/* Number of buffers for use in the "fast" host interface */
+#define ICAN3_TX_BUFFERS	512
+#define ICAN3_RX_BUFFERS	1024
+
+/* SJA1000 Clock Input */
+#define ICAN3_CAN_CLOCK		8000000
+
+/* Driver Name */
+#define DRV_NAME "janz-ican3"
+
+/* DPM Control Registers -- starts at offset 0x100 in the MODULbus registers */
+struct ican3_dpm_control {
+	/* window address register */
+	u8 window_address;
+	u8 unused1;
+
+	/*
+	 * Read access: clear interrupt from microcontroller
+	 * Write access: send interrupt to microcontroller
+	 */
+	u8 interrupt;
+	u8 unused2;
+
+	/* write-only: reset all hardware on the module */
+	u8 hwreset;
+	u8 unused3;
+
+	/* write-only: generate an interrupt to the TPU */
+	u8 tpuinterrupt;
+};
+
+struct ican3_dev {
+
+	/* must be the first member */
+	struct can_priv can;
+
+	/* CAN network device */
+	struct net_device *ndev;
+	struct napi_struct napi;
+
+	/* module number */
+	unsigned int num;
+
+	/* base address of registers and IRQ */
+	struct janz_cmodio_onboard_regs __iomem *ctrl;
+	struct ican3_dpm_control __iomem *dpmctrl;
+	void __iomem *dpm;
+	int irq;
+
+	/* CAN bus termination status */
+	struct completion termination_comp;
+	bool termination_enabled;
+
+	/* CAN bus error status registers */
+	struct completion buserror_comp;
+	struct can_berr_counter bec;
+
+	/* 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
+	 * function will not be preempted and end up reading data from a
+	 * different DPM page than it expects.
+	 */
+	spinlock_t lock;
+
+	/* new host interface */
+	unsigned int rx_int;
+	unsigned int rx_num;
+	unsigned int tx_num;
+
+	/* fast host interface */
+	unsigned int fastrx_start;
+	unsigned int fastrx_num;
+	unsigned int fasttx_start;
+	unsigned int fasttx_num;
+
+	/* first free DPM page */
+	unsigned int free_page;
+};
+
+struct ican3_msg {
+	u8 control;
+	u8 spec;
+	__le16 len;
+	u8 data[252];
+};
+
+struct ican3_new_desc {
+	u8 control;
+	u8 pointer;
+};
+
+struct ican3_fast_desc {
+	u8 control;
+	u8 command;
+	u8 data[14];
+};
+
+/* write to the window basic address register */
+static inline void ican3_set_page(struct ican3_dev *mod, unsigned int page)
+{
+	BUG_ON(page >= DPM_NUM_PAGES);
+	iowrite8(page, &mod->dpmctrl->window_address);
+}
+
+/*
+ * ICAN3 "old-style" host interface
+ */
+
+/*
+ * Receive a message from the ICAN3 "old-style" firmware interface
+ *
+ * LOCKING: must hold mod->lock
+ *
+ * returns 0 on success, -ENOMEM when no message exists
+ */
+static int ican3_old_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	unsigned int mbox, mbox_page;
+	u8 locl, peer, xord;
+
+	/* get the MSYNC registers */
+	ican3_set_page(mod, QUEUE_OLD_CONTROL);
+	peer = ioread8(mod->dpm + MSYNC_PEER);
+	locl = ioread8(mod->dpm + MSYNC_LOCL);
+	xord = locl ^ peer;
+
+	if ((xord & MSYNC_RB_MASK) == 0x00) {
+		netdev_dbg(mod->ndev, "no mbox for reading\n");
+		return -ENOMEM;
+	}
+
+	/* find the first free mbox to read */
+	if ((xord & MSYNC_RB_MASK) == MSYNC_RB_MASK)
+		mbox = (xord & MSYNC_RBLW) ? MSYNC_RB0 : MSYNC_RB1;
+	else
+		mbox = (xord & MSYNC_RB0) ? MSYNC_RB0 : MSYNC_RB1;
+
+	/* copy the message */
+	mbox_page = (mbox == MSYNC_RB0) ? QUEUE_OLD_RB0 : QUEUE_OLD_RB1;
+	ican3_set_page(mod, mbox_page);
+	memcpy_fromio(msg, mod->dpm, sizeof(*msg));
+
+	/*
+	 * notify the firmware that the read buffer is available
+	 * for it to fill again
+	 */
+	locl ^= mbox;
+
+	ican3_set_page(mod, QUEUE_OLD_CONTROL);
+	iowrite8(locl, mod->dpm + MSYNC_LOCL);
+	return 0;
+}
+
+/*
+ * Send a message through the "old-style" firmware interface
+ *
+ * LOCKING: must hold mod->lock
+ *
+ * returns 0 on success, -ENOMEM when no free space exists
+ */
+static int ican3_old_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	unsigned int mbox, mbox_page;
+	u8 locl, peer, xord;
+
+	/* get the MSYNC registers */
+	ican3_set_page(mod, QUEUE_OLD_CONTROL);
+	peer = ioread8(mod->dpm + MSYNC_PEER);
+	locl = ioread8(mod->dpm + MSYNC_LOCL);
+	xord = locl ^ peer;
+
+	if ((xord & MSYNC_WB_MASK) == MSYNC_WB_MASK) {
+		netdev_err(mod->ndev, "no mbox for writing\n");
+		return -ENOMEM;
+	}
+
+	/* calculate a free mbox to use */
+	mbox = (xord & MSYNC_WB0) ? MSYNC_WB1 : MSYNC_WB0;
+
+	/* copy the message to the DPM */
+	mbox_page = (mbox == MSYNC_WB0) ? QUEUE_OLD_WB0 : QUEUE_OLD_WB1;
+	ican3_set_page(mod, mbox_page);
+	memcpy_toio(mod->dpm, msg, sizeof(*msg));
+
+	locl ^= mbox;
+	if (mbox == MSYNC_WB1)
+		locl |= MSYNC_WBLW;
+
+	ican3_set_page(mod, QUEUE_OLD_CONTROL);
+	iowrite8(locl, mod->dpm + MSYNC_LOCL);
+	return 0;
+}
+
+/*
+ * ICAN3 "new-style" Host Interface Setup
+ */
+
+static void ican3_init_new_host_interface(struct ican3_dev *mod)
+{
+	struct ican3_new_desc desc;
+	unsigned long flags;
+	void __iomem *dst;
+	int i;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	/* setup the internal datastructures for RX */
+	mod->rx_num = 0;
+	mod->rx_int = 0;
+
+	/* tohost queue descriptors are in page 5 */
+	ican3_set_page(mod, QUEUE_TOHOST);
+	dst = mod->dpm;
+
+	/* initialize the tohost (rx) queue descriptors: pages 9-24 */
+	for (i = 0; i < ICAN3_NEW_BUFFERS; i++) {
+		desc.control = DESC_INTERRUPT | DESC_LEN(1); /* I L=1 */
+		desc.pointer = mod->free_page;
+
+		/* set wrap flag on last buffer */
+		if (i == ICAN3_NEW_BUFFERS - 1)
+			desc.control |= DESC_WRAP;
+
+		memcpy_toio(dst, &desc, sizeof(desc));
+		dst += sizeof(desc);
+		mod->free_page++;
+	}
+
+	/* fromhost (tx) mid queue descriptors are in page 6 */
+	ican3_set_page(mod, QUEUE_FROMHOST_MID);
+	dst = mod->dpm;
+
+	/* setup the internal datastructures for TX */
+	mod->tx_num = 0;
+
+	/* initialize the fromhost mid queue descriptors: pages 25-40 */
+	for (i = 0; i < ICAN3_NEW_BUFFERS; i++) {
+		desc.control = DESC_VALID | DESC_LEN(1); /* V L=1 */
+		desc.pointer = mod->free_page;
+
+		/* set wrap flag on last buffer */
+		if (i == ICAN3_NEW_BUFFERS - 1)
+			desc.control |= DESC_WRAP;
+
+		memcpy_toio(dst, &desc, sizeof(desc));
+		dst += sizeof(desc);
+		mod->free_page++;
+	}
+
+	/* fromhost hi queue descriptors are in page 7 */
+	ican3_set_page(mod, QUEUE_FROMHOST_HIGH);
+	dst = mod->dpm;
+
+	/* initialize only a single buffer in the fromhost hi queue (unused) */
+	desc.control = DESC_VALID | DESC_WRAP | DESC_LEN(1); /* VW L=1 */
+	desc.pointer = mod->free_page;
+	memcpy_toio(dst, &desc, sizeof(desc));
+	mod->free_page++;
+
+	/* fromhost low queue descriptors are in page 8 */
+	ican3_set_page(mod, QUEUE_FROMHOST_LOW);
+	dst = mod->dpm;
+
+	/* initialize only a single buffer in the fromhost low queue (unused) */
+	desc.control = DESC_VALID | DESC_WRAP | DESC_LEN(1); /* VW L=1 */
+	desc.pointer = mod->free_page;
+	memcpy_toio(dst, &desc, sizeof(desc));
+	mod->free_page++;
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+}
+
+/*
+ * ICAN3 Fast Host Interface Setup
+ */
+
+static void ican3_init_fast_host_interface(struct ican3_dev *mod)
+{
+	struct ican3_fast_desc desc;
+	unsigned long flags;
+	unsigned int addr;
+	void __iomem *dst;
+	int i;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	/* save the start recv page */
+	mod->fastrx_start = mod->free_page;
+	mod->fastrx_num = 0;
+
+	/* build a single fast tohost queue descriptor */
+	memset(&desc, 0, sizeof(desc));
+	desc.control = 0x00;
+	desc.command = 1;
+
+	/* build the tohost queue descriptor ring in memory */
+	addr = 0;
+	for (i = 0; i < ICAN3_RX_BUFFERS; i++) {
+
+		/* set the wrap bit on the last buffer */
+		if (i == ICAN3_RX_BUFFERS - 1)
+			desc.control |= DESC_WRAP;
+
+		/* switch to the correct page */
+		ican3_set_page(mod, mod->free_page);
+
+		/* copy the descriptor to the DPM */
+		dst = mod->dpm + addr;
+		memcpy_toio(dst, &desc, sizeof(desc));
+		addr += sizeof(desc);
+
+		/* move to the next page if necessary */
+		if (addr >= DPM_PAGE_SIZE) {
+			addr = 0;
+			mod->free_page++;
+		}
+	}
+
+	/* make sure we page-align the next queue */
+	if (addr != 0)
+		mod->free_page++;
+
+	/* save the start xmit page */
+	mod->fasttx_start = mod->free_page;
+	mod->fasttx_num = 0;
+
+	/* build a single fast fromhost queue descriptor */
+	memset(&desc, 0, sizeof(desc));
+	desc.control = DESC_VALID;
+	desc.command = 1;
+
+	/* build the fromhost queue descriptor ring in memory */
+	addr = 0;
+	for (i = 0; i < ICAN3_TX_BUFFERS; i++) {
+
+		/* set the wrap bit on the last buffer */
+		if (i == ICAN3_TX_BUFFERS - 1)
+			desc.control |= DESC_WRAP;
+
+		/* switch to the correct page */
+		ican3_set_page(mod, mod->free_page);
+
+		/* copy the descriptor to the DPM */
+		dst = mod->dpm + addr;
+		memcpy_toio(dst, &desc, sizeof(desc));
+		addr += sizeof(desc);
+
+		/* move to the next page if necessary */
+		if (addr >= DPM_PAGE_SIZE) {
+			addr = 0;
+			mod->free_page++;
+		}
+	}
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+}
+
+/*
+ * ICAN3 "new-style" Host Interface Message Helpers
+ */
+
+/*
+ * LOCKING: must hold mod->lock
+ */
+static int ican3_new_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	struct ican3_new_desc desc;
+	void __iomem *desc_addr = mod->dpm + (mod->tx_num * sizeof(desc));
+
+	/* switch to the fromhost mid queue, and read the buffer descriptor */
+	ican3_set_page(mod, QUEUE_FROMHOST_MID);
+	memcpy_fromio(&desc, desc_addr, sizeof(desc));
+
+	if (!(desc.control & DESC_VALID)) {
+		netdev_dbg(mod->ndev, "%s: no free buffers\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* switch to the data page, copy the data */
+	ican3_set_page(mod, desc.pointer);
+	memcpy_toio(mod->dpm, msg, sizeof(*msg));
+
+	/* switch back to the descriptor, set the valid bit, write it back */
+	ican3_set_page(mod, QUEUE_FROMHOST_MID);
+	desc.control ^= DESC_VALID;
+	memcpy_toio(desc_addr, &desc, sizeof(desc));
+
+	/* update the tx number */
+	mod->tx_num = (desc.control & DESC_WRAP) ? 0 : (mod->tx_num + 1);
+	return 0;
+}
+
+/*
+ * LOCKING: must hold mod->lock
+ */
+static int ican3_new_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	struct ican3_new_desc desc;
+	void __iomem *desc_addr = mod->dpm + (mod->rx_num * sizeof(desc));
+
+	/* switch to the tohost queue, and read the buffer descriptor */
+	ican3_set_page(mod, QUEUE_TOHOST);
+	memcpy_fromio(&desc, desc_addr, sizeof(desc));
+
+	if (!(desc.control & DESC_VALID)) {
+		netdev_dbg(mod->ndev, "%s: no buffers to recv\n", __func__);
+		return -ENOMEM;
+	}
+
+	/* switch to the data page, copy the data */
+	ican3_set_page(mod, desc.pointer);
+	memcpy_fromio(msg, mod->dpm, sizeof(*msg));
+
+	/* switch back to the descriptor, toggle the valid bit, write it back */
+	ican3_set_page(mod, QUEUE_TOHOST);
+	desc.control ^= DESC_VALID;
+	memcpy_toio(desc_addr, &desc, sizeof(desc));
+
+	/* update the rx number */
+	mod->rx_num = (desc.control & DESC_WRAP) ? 0 : (mod->rx_num + 1);
+	return 0;
+}
+
+/*
+ * Message Send / Recv Helpers
+ */
+
+static int ican3_send_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	if (mod->iftype == 0)
+		ret = ican3_old_send_msg(mod, msg);
+	else
+		ret = ican3_new_send_msg(mod, msg);
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+	return ret;
+}
+
+static int ican3_recv_msg(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	if (mod->iftype == 0)
+		ret = ican3_old_recv_msg(mod, msg);
+	else
+		ret = ican3_new_recv_msg(mod, msg);
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+	return ret;
+}
+
+/*
+ * Quick Pre-constructed Messages
+ */
+
+static int ican3_msg_connect(struct ican3_dev *mod)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_CONNECTI;
+	msg.len = cpu_to_le16(0);
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_msg_disconnect(struct ican3_dev *mod)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_DISCONNECT;
+	msg.len = cpu_to_le16(0);
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_msg_newhostif(struct ican3_dev *mod)
+{
+	struct ican3_msg msg;
+	int ret;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_NEWHOSTIF;
+	msg.len = cpu_to_le16(0);
+
+	/* If we're not using the old interface, switching seems bogus */
+	WARN_ON(mod->iftype != 0);
+
+	ret = ican3_send_msg(mod, &msg);
+	if (ret)
+		return ret;
+
+	/* mark the module as using the new host interface */
+	mod->iftype = 1;
+	return 0;
+}
+
+static int ican3_msg_fasthostif(struct ican3_dev *mod)
+{
+	struct ican3_msg msg;
+	unsigned int addr;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_INITFDPMQUEUE;
+	msg.len = cpu_to_le16(8);
+
+	/* write the tohost queue start address */
+	addr = DPM_PAGE_ADDR(mod->fastrx_start);
+	msg.data[0] = addr & 0xff;
+	msg.data[1] = (addr >> 8) & 0xff;
+	msg.data[2] = (addr >> 16) & 0xff;
+	msg.data[3] = (addr >> 24) & 0xff;
+
+	/* write the fromhost queue start address */
+	addr = DPM_PAGE_ADDR(mod->fasttx_start);
+	msg.data[4] = addr & 0xff;
+	msg.data[5] = (addr >> 8) & 0xff;
+	msg.data[6] = (addr >> 16) & 0xff;
+	msg.data[7] = (addr >> 24) & 0xff;
+
+	/* If we're not using the new interface yet, we cannot do this */
+	WARN_ON(mod->iftype != 1);
+
+	return ican3_send_msg(mod, &msg);
+}
+
+/*
+ * Setup the CAN filter to either accept or reject all
+ * messages from the CAN bus.
+ */
+static int ican3_set_id_filter(struct ican3_dev *mod, bool accept)
+{
+	struct ican3_msg msg;
+	int ret;
+
+	/* Standard Frame Format */
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_SETAFILMASK;
+	msg.len = cpu_to_le16(5);
+	msg.data[0] = 0x00; /* IDLo LSB */
+	msg.data[1] = 0x00; /* IDLo MSB */
+	msg.data[2] = 0xff; /* IDHi LSB */
+	msg.data[3] = 0x07; /* IDHi MSB */
+
+	/* accept all frames for fast host if, or reject all frames */
+	msg.data[4] = accept ? SETAFILMASK_FASTIF : SETAFILMASK_REJECT;
+
+	ret = ican3_send_msg(mod, &msg);
+	if (ret)
+		return ret;
+
+	/* Extended Frame Format */
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_SETAFILMASK;
+	msg.len = cpu_to_le16(13);
+	msg.data[0] = 0;    /* MUX = 0 */
+	msg.data[1] = 0x00; /* IDLo LSB */
+	msg.data[2] = 0x00;
+	msg.data[3] = 0x00;
+	msg.data[4] = 0x20; /* IDLo MSB */
+	msg.data[5] = 0xff; /* IDHi LSB */
+	msg.data[6] = 0xff;
+	msg.data[7] = 0xff;
+	msg.data[8] = 0x3f; /* IDHi MSB */
+
+	/* accept all frames for fast host if, or reject all frames */
+	msg.data[9] = accept ? SETAFILMASK_FASTIF : SETAFILMASK_REJECT;
+
+	return ican3_send_msg(mod, &msg);
+}
+
+/*
+ * Bring the CAN bus online or offline
+ */
+static int ican3_set_bus_state(struct ican3_dev *mod, bool on)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = on ? MSG_CONREQ : MSG_COFFREQ;
+	msg.len = cpu_to_le16(0);
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_set_termination(struct ican3_dev *mod, bool on)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_HWCONF;
+	msg.len = cpu_to_le16(2);
+	msg.data[0] = 0x00;
+	msg.data[1] = on ? HWCONF_TERMINATE_ON : HWCONF_TERMINATE_OFF;
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_send_inquiry(struct ican3_dev *mod, u8 subspec)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_INQUIRY;
+	msg.len = cpu_to_le16(2);
+	msg.data[0] = subspec;
+	msg.data[1] = 0x00;
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_set_buserror(struct ican3_dev *mod, u8 quota)
+{
+	struct ican3_msg msg;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_CCONFREQ;
+	msg.len = cpu_to_le16(2);
+	msg.data[0] = 0x00;
+	msg.data[1] = quota;
+
+	return ican3_send_msg(mod, &msg);
+}
+
+/*
+ * ICAN3 to Linux CAN Frame Conversion
+ */
+
+static void ican3_to_can_frame(struct ican3_dev *mod,
+			       struct ican3_fast_desc *desc,
+			       struct can_frame *cf)
+{
+	if ((desc->command & ICAN3_CAN_TYPE_MASK) == ICAN3_CAN_TYPE_SFF) {
+		if (desc->data[1] & ICAN3_SFF_RTR)
+			cf->can_id |= CAN_RTR_FLAG;
+
+		cf->can_id |= desc->data[0] << 3;
+		cf->can_id |= (desc->data[1] & 0xe0) >> 5;
+		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 = get_can_dlc(desc->data[0] & ICAN3_CAN_DLC_MASK);
+		if (desc->data[0] & ICAN3_EFF_RTR)
+			cf->can_id |= CAN_RTR_FLAG;
+
+		if (desc->data[0] & ICAN3_EFF) {
+			cf->can_id |= CAN_EFF_FLAG;
+			cf->can_id |= desc->data[2] << 21; /* 28-21 */
+			cf->can_id |= desc->data[3] << 13; /* 20-13 */
+			cf->can_id |= desc->data[4] << 5;  /* 12-5  */
+			cf->can_id |= (desc->data[5] & 0xf8) >> 3;
+		} else {
+			cf->can_id |= desc->data[2] << 3;  /* 10-3  */
+			cf->can_id |= desc->data[3] >> 5;  /* 2-0   */
+		}
+
+		memcpy(cf->data, &desc->data[6], cf->can_dlc);
+	}
+}
+
+static void can_frame_to_ican3(struct ican3_dev *mod,
+			       struct can_frame *cf,
+			       struct ican3_fast_desc *desc)
+{
+	/* clear out any stale data in the descriptor */
+	memset(desc->data, 0, sizeof(desc->data));
+
+	/* we always use the extended format, with the ECHO flag set */
+	desc->command = ICAN3_CAN_TYPE_EFF;
+	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;
+
+	/* pack the id into the correct places */
+	if (cf->can_id & CAN_EFF_FLAG) {
+		desc->data[0] |= ICAN3_EFF;
+		desc->data[2] = (cf->can_id & 0x1fe00000) >> 21; /* 28-21 */
+		desc->data[3] = (cf->can_id & 0x001fe000) >> 13; /* 20-13 */
+		desc->data[4] = (cf->can_id & 0x00001fe0) >> 5;  /* 12-5  */
+		desc->data[5] = (cf->can_id & 0x0000001f) << 3;  /* 4-0   */
+	} else {
+		desc->data[2] = (cf->can_id & 0x7F8) >> 3; /* bits 10-3 */
+		desc->data[3] = (cf->can_id & 0x007) << 5; /* bits 2-0  */
+	}
+
+	/* copy the data bits into the descriptor */
+	memcpy(&desc->data[6], cf->data, cf->can_dlc);
+}
+
+/*
+ * Interrupt Handling
+ */
+
+/*
+ * Handle an ID + Version message response from the firmware. We never generate
+ * this message in production code, but it is very useful when debugging to be
+ * able to display this message.
+ */
+static void ican3_handle_idvers(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	netdev_dbg(mod->ndev, "IDVERS response: %s\n", msg->data);
+}
+
+static void ican3_handle_msglost(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	struct net_device *dev = mod->ndev;
+	struct net_device_stats *stats = &dev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	/*
+	 * Report that communication messages with the microcontroller firmware
+	 * are being lost. These are never CAN frames, so we do not generate an
+	 * error frame for userspace
+	 */
+	if (msg->spec == MSG_MSGLOST) {
+		netdev_err(mod->ndev, "lost %d control messages\n", msg->data[0]);
+		return;
+	}
+
+	/*
+	 * Oops, this indicates that we have lost messages in the fast queue,
+	 * which are exclusively CAN messages. Our driver isn't reading CAN
+	 * frames fast enough.
+	 *
+	 * We'll pretend that the SJA1000 told us that it ran out of buffer
+	 * space, because there is not a better message for this.
+	 */
+	skb = alloc_can_err_skb(dev, &cf);
+	if (skb) {
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+		netif_rx(skb);
+	}
+}
+
+/*
+ * Handle CAN Event Indication Messages from the firmware
+ *
+ * The ICAN3 firmware provides the values of some SJA1000 registers when it
+ * generates this message. The code below is largely copied from the
+ * drivers/net/can/sja1000/sja1000.c file, and adapted as necessary
+ */
+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 isrc, ecc, status, rxerr, txerr;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	/* we can only handle the SJA1000 part */
+	if (msg->data[1] != CEVTIND_CHIP_SJA1000) {
+		netdev_err(mod->ndev, "unable to handle errors on non-SJA1000\n");
+		return -ENODEV;
+	}
+
+	/* check the message length for sanity */
+	if (le16_to_cpu(msg->len) < 6) {
+		netdev_err(mod->ndev, "error message too short\n");
+		return -EINVAL;
+	}
+
+	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;
+		netdev_dbg(mod->ndev, "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) {
+			netdev_err(mod->ndev, "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) {
+		netdev_dbg(mod->ndev, "data overrun interrupt\n");
+		cf->can_id |= CAN_ERR_CRTL;
+		cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+		stats->rx_over_errors++;
+		stats->rx_errors++;
+	}
+
+	/* error warning + passive interrupt */
+	if (isrc == CEVTIND_EI) {
+		netdev_dbg(mod->ndev, "error warning + passive interrupt\n");
+		if (status & SR_BS) {
+			state = CAN_STATE_BUS_OFF;
+			cf->can_id |= CAN_ERR_BUSOFF;
+			mod->can.can_stats.bus_off++;
+			can_bus_off(dev);
+		} else if (status & SR_ES) {
+			if (rxerr >= 128 || txerr >= 128)
+				state = CAN_STATE_ERROR_PASSIVE;
+			else
+				state = CAN_STATE_ERROR_WARNING;
+		} else {
+			state = CAN_STATE_ERROR_ACTIVE;
+		}
+	}
+
+	/* bus error interrupt */
+	if (isrc == CEVTIND_BEI) {
+		mod->can.can_stats.bus_error++;
+		cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+		switch (ecc & ECC_MASK) {
+		case ECC_BIT:
+			cf->data[2] |= CAN_ERR_PROT_BIT;
+			break;
+		case ECC_FORM:
+			cf->data[2] |= CAN_ERR_PROT_FORM;
+			break;
+		case ECC_STUFF:
+			cf->data[2] |= CAN_ERR_PROT_STUFF;
+			break;
+		default:
+			cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+			cf->data[3] = ecc & ECC_SEG;
+			break;
+		}
+
+		if (!(ecc & ECC_DIR))
+			cf->data[2] |= CAN_ERR_PROT_TX;
+
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+	}
+
+	if (state != mod->can.state && (state == CAN_STATE_ERROR_WARNING ||
+					state == CAN_STATE_ERROR_PASSIVE)) {
+		cf->can_id |= CAN_ERR_CRTL;
+		if (state == CAN_STATE_ERROR_WARNING) {
+			mod->can.can_stats.error_warning++;
+			cf->data[1] = (txerr > rxerr) ?
+				CAN_ERR_CRTL_TX_WARNING :
+				CAN_ERR_CRTL_RX_WARNING;
+		} else {
+			mod->can.can_stats.error_passive++;
+			cf->data[1] = (txerr > rxerr) ?
+				CAN_ERR_CRTL_TX_PASSIVE :
+				CAN_ERR_CRTL_RX_PASSIVE;
+		}
+
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+	}
+
+	mod->can.state = state;
+	netif_rx(skb);
+	return 0;
+}
+
+static void ican3_handle_inquiry(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	switch (msg->data[0]) {
+	case INQUIRY_STATUS:
+	case INQUIRY_EXTENDED:
+		mod->bec.rxerr = msg->data[5];
+		mod->bec.txerr = msg->data[6];
+		complete(&mod->buserror_comp);
+		break;
+	case INQUIRY_TERMINATION:
+		mod->termination_enabled = msg->data[6] & HWCONF_TERMINATE_ON;
+		complete(&mod->termination_comp);
+		break;
+	default:
+		netdev_err(mod->ndev, "received an unknown inquiry response\n");
+		break;
+	}
+}
+
+static void ican3_handle_unknown_message(struct ican3_dev *mod,
+					struct ican3_msg *msg)
+{
+	netdev_warn(mod->ndev, "received unknown message: spec 0x%.2x length %d\n",
+			   msg->spec, le16_to_cpu(msg->len));
+}
+
+/*
+ * Handle a control message from the firmware
+ */
+static void ican3_handle_message(struct ican3_dev *mod, struct ican3_msg *msg)
+{
+	netdev_dbg(mod->ndev, "%s: modno %d spec 0x%.2x len %d bytes\n", __func__,
+			   mod->num, msg->spec, le16_to_cpu(msg->len));
+
+	switch (msg->spec) {
+	case MSG_IDVERS:
+		ican3_handle_idvers(mod, msg);
+		break;
+	case MSG_MSGLOST:
+	case MSG_FMSGLOST:
+		ican3_handle_msglost(mod, msg);
+		break;
+	case MSG_CEVTIND:
+		ican3_handle_cevtind(mod, msg);
+		break;
+	case MSG_INQUIRY:
+		ican3_handle_inquiry(mod, msg);
+		break;
+	default:
+		ican3_handle_unknown_message(mod, msg);
+		break;
+	}
+}
+
+/*
+ * 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)
+{
+	skb = can_create_echo_skb(skb);
+	if (!skb)
+		return;
+
+	/* 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
+ */
+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));
+	control = ioread8(&desc->control);
+
+	/* if the control bits are not valid, then we have no more space */
+	if (!(control & DESC_VALID))
+		return false;
+
+	return true;
+}
+
+/*
+ * Receive one CAN frame from the hardware
+ *
+ * CONTEXT: must be called from user context
+ */
+static int ican3_recv_skb(struct ican3_dev *mod)
+{
+	struct net_device *ndev = mod->ndev;
+	struct net_device_stats *stats = &ndev->stats;
+	struct ican3_fast_desc desc;
+	void __iomem *desc_addr;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+	unsigned long flags;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	/* copy the whole descriptor */
+	ican3_set_page(mod, mod->fastrx_start + (mod->fastrx_num / 16));
+	desc_addr = mod->dpm + ((mod->fastrx_num % 16) * sizeof(desc));
+	memcpy_fromio(&desc, desc_addr, sizeof(desc));
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+
+	/* check that we actually have a CAN frame */
+	if (!(desc.control & DESC_VALID))
+		return -ENOBUFS;
+
+	/* allocate an skb */
+	skb = alloc_can_skb(ndev, &cf);
+	if (unlikely(skb == NULL)) {
+		stats->rx_dropped++;
+		goto err_noalloc;
+	}
+
+	/* convert the ICAN3 frame into Linux CAN format */
+	ican3_to_can_frame(mod, &desc, cf);
+
+	/*
+	 * 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 */
+	desc.control ^= DESC_VALID;
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	ican3_set_page(mod, mod->fastrx_start + (mod->fastrx_num / 16));
+	memcpy_toio(desc_addr, &desc, 1);
+
+	/* update the next buffer pointer */
+	mod->fastrx_num = (desc.control & DESC_WRAP) ? 0
+						     : (mod->fastrx_num + 1);
+
+	/* there are still more buffers to process */
+	spin_unlock_irqrestore(&mod->lock, flags);
+	return 0;
+}
+
+static int ican3_napi(struct napi_struct *napi, int budget)
+{
+	struct ican3_dev *mod = container_of(napi, struct ican3_dev, napi);
+	unsigned long flags;
+	int received = 0;
+	int ret;
+
+	/* process all communication messages */
+	while (true) {
+		struct ican3_msg uninitialized_var(msg);
+		ret = ican3_recv_msg(mod, &msg);
+		if (ret)
+			break;
+
+		ican3_handle_message(mod, &msg);
+	}
+
+	/* process all CAN frames from the fast interface */
+	while (received < budget) {
+		ret = ican3_recv_skb(mod);
+		if (ret)
+			break;
+
+		received++;
+	}
+
+	/* We have processed all packets that the adapter had, but it
+	 * was less than our budget, stop polling */
+	if (received < budget)
+		napi_complete(napi);
+
+	spin_lock_irqsave(&mod->lock, flags);
+
+	/* Wake up the transmit queue if necessary */
+	if (netif_queue_stopped(mod->ndev) && ican3_txok(mod))
+		netif_wake_queue(mod->ndev);
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+
+	/* re-enable interrupt generation */
+	iowrite8(1 << mod->num, &mod->ctrl->int_enable);
+	return received;
+}
+
+static irqreturn_t ican3_irq(int irq, void *dev_id)
+{
+	struct ican3_dev *mod = dev_id;
+	u8 stat;
+
+	/*
+	 * The interrupt status register on this device reports interrupts
+	 * as zeroes instead of using ones like most other devices
+	 */
+	stat = ioread8(&mod->ctrl->int_disable) & (1 << mod->num);
+	if (stat == (1 << mod->num))
+		return IRQ_NONE;
+
+	/* clear the MODULbus interrupt from the microcontroller */
+	ioread8(&mod->dpmctrl->interrupt);
+
+	/* disable interrupt generation, schedule the NAPI poller */
+	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
+	napi_schedule(&mod->napi);
+	return IRQ_HANDLED;
+}
+
+/*
+ * Firmware reset, startup, and shutdown
+ */
+
+/*
+ * Reset an ICAN module to its power-on state
+ *
+ * CONTEXT: no network device registered
+ */
+static int ican3_reset_module(struct ican3_dev *mod)
+{
+	unsigned long start;
+	u8 runold, runnew;
+
+	/* disable interrupts so no more work is scheduled */
+	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
+
+	/* the first unallocated page in the DPM is #9 */
+	mod->free_page = DPM_FREE_START;
+
+	ican3_set_page(mod, QUEUE_OLD_CONTROL);
+	runold = ioread8(mod->dpm + TARGET_RUNNING);
+
+	/* reset the module */
+	iowrite8(0x00, &mod->dpmctrl->hwreset);
+
+	/* wait until the module has finished resetting and is running */
+	start = jiffies;
+	do {
+		ican3_set_page(mod, QUEUE_OLD_CONTROL);
+		runnew = ioread8(mod->dpm + TARGET_RUNNING);
+		if (runnew == (runold ^ 0xff))
+			return 0;
+
+		msleep(10);
+	} while (time_before(jiffies, start + HZ / 4));
+
+	netdev_err(mod->ndev, "failed to reset CAN module\n");
+	return -ETIMEDOUT;
+}
+
+static void ican3_shutdown_module(struct ican3_dev *mod)
+{
+	ican3_msg_disconnect(mod);
+	ican3_reset_module(mod);
+}
+
+/*
+ * Startup an ICAN module, bringing it into fast mode
+ */
+static int ican3_startup_module(struct ican3_dev *mod)
+{
+	int ret;
+
+	ret = ican3_reset_module(mod);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to reset module\n");
+		return ret;
+	}
+
+	/* re-enable interrupts so we can send messages */
+	iowrite8(1 << mod->num, &mod->ctrl->int_enable);
+
+	ret = ican3_msg_connect(mod);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to connect to module\n");
+		return ret;
+	}
+
+	ican3_init_new_host_interface(mod);
+	ret = ican3_msg_newhostif(mod);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to switch to new-style interface\n");
+		return ret;
+	}
+
+	/* default to "termination on" */
+	ret = ican3_set_termination(mod, true);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to enable termination\n");
+		return ret;
+	}
+
+	/* default to "bus errors enabled" */
+	ret = ican3_set_buserror(mod, 1);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to set bus-error\n");
+		return ret;
+	}
+
+	ican3_init_fast_host_interface(mod);
+	ret = ican3_msg_fasthostif(mod);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to switch to fast host interface\n");
+		return ret;
+	}
+
+	ret = ican3_set_id_filter(mod, true);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to set acceptance filter\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * CAN Network Device
+ */
+
+static int ican3_open(struct net_device *ndev)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	int ret;
+
+	/* open the CAN layer */
+	ret = open_candev(ndev);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to start CAN layer\n");
+		return ret;
+	}
+
+	/* bring the bus online */
+	ret = ican3_set_bus_state(mod, true);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to set bus-on\n");
+		close_candev(ndev);
+		return ret;
+	}
+
+	/* start up the network device */
+	mod->can.state = CAN_STATE_ERROR_ACTIVE;
+	netif_start_queue(ndev);
+
+	return 0;
+}
+
+static int ican3_stop(struct net_device *ndev)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	int ret;
+
+	/* stop the network device xmit routine */
+	netif_stop_queue(ndev);
+	mod->can.state = CAN_STATE_STOPPED;
+
+	/* bring the bus offline, stop receiving packets */
+	ret = ican3_set_bus_state(mod, false);
+	if (ret) {
+		netdev_err(mod->ndev, "unable to set bus-off\n");
+		return ret;
+	}
+
+	/* drop all outstanding echo skbs */
+	skb_queue_purge(&mod->echoq);
+
+	/* close the CAN layer */
+	close_candev(ndev);
+	return 0;
+}
+
+static int ican3_xmit(struct sk_buff *skb, struct net_device *ndev)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	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)) {
+		netdev_err(mod->ndev, "BUG: no free descriptors\n");
+		spin_unlock_irqrestore(&mod->lock, flags);
+		return NETDEV_TX_BUSY;
+	}
+
+	/* copy the control bits of the descriptor */
+	ican3_set_page(mod, mod->fasttx_start + (mod->fasttx_num / 16));
+	desc_addr = mod->dpm + ((mod->fasttx_num % 16) * sizeof(desc));
+	memset(&desc, 0, sizeof(desc));
+	memcpy_fromio(&desc, desc_addr, 1);
+
+	/* convert the Linux CAN frame into ICAN3 format */
+	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
+	 */
+	desc.control |= DESC_IVALID;
+	memcpy_toio(desc_addr, &desc, sizeof(desc));
+
+	/* generate a MODULbus interrupt to the microcontroller */
+	iowrite8(0x01, &mod->dpmctrl->interrupt);
+
+	desc.control ^= DESC_VALID;
+	memcpy_toio(desc_addr, &desc, sizeof(desc));
+
+	/* update the next buffer pointer */
+	mod->fasttx_num = (desc.control & DESC_WRAP) ? 0
+						     : (mod->fasttx_num + 1);
+
+	/* if there is no free descriptor space, stop the transmit queue */
+	if (!ican3_txok(mod))
+		netif_stop_queue(ndev);
+
+	spin_unlock_irqrestore(&mod->lock, flags);
+	return NETDEV_TX_OK;
+}
+
+static const struct net_device_ops ican3_netdev_ops = {
+	.ndo_open	= ican3_open,
+	.ndo_stop	= ican3_stop,
+	.ndo_start_xmit	= ican3_xmit,
+	.ndo_change_mtu = can_change_mtu,
+};
+
+/*
+ * Low-level CAN Device
+ */
+
+/* This structure was stolen from drivers/net/can/sja1000/sja1000.c */
+static const struct can_bittiming_const ican3_bittiming_const = {
+	.name = DRV_NAME,
+	.tseg1_min = 1,
+	.tseg1_max = 16,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 64,
+	.brp_inc = 1,
+};
+
+/*
+ * This routine was stolen from drivers/net/can/sja1000/sja1000.c
+ *
+ * The bittiming register command for the ICAN3 just sets the bit timing
+ * registers on the SJA1000 chip directly
+ */
+static int ican3_set_bittiming(struct net_device *ndev)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	struct can_bittiming *bt = &mod->can.bittiming;
+	struct ican3_msg msg;
+	u8 btr0, btr1;
+
+	btr0 = ((bt->brp - 1) & 0x3f) | (((bt->sjw - 1) & 0x3) << 6);
+	btr1 = ((bt->prop_seg + bt->phase_seg1 - 1) & 0xf) |
+		(((bt->phase_seg2 - 1) & 0x7) << 4);
+	if (mod->can.ctrlmode & CAN_CTRLMODE_3_SAMPLES)
+		btr1 |= 0x80;
+
+	memset(&msg, 0, sizeof(msg));
+	msg.spec = MSG_CBTRREQ;
+	msg.len = cpu_to_le16(4);
+	msg.data[0] = 0x00;
+	msg.data[1] = 0x00;
+	msg.data[2] = btr0;
+	msg.data[3] = btr1;
+
+	return ican3_send_msg(mod, &msg);
+}
+
+static int ican3_set_mode(struct net_device *ndev, enum can_mode mode)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	int ret;
+
+	if (mode != CAN_MODE_START)
+		return -ENOTSUPP;
+
+	/* bring the bus online */
+	ret = ican3_set_bus_state(mod, true);
+	if (ret) {
+		netdev_err(ndev, "unable to set bus-on\n");
+		return ret;
+	}
+
+	/* start up the network device */
+	mod->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	if (netif_queue_stopped(ndev))
+		netif_wake_queue(ndev);
+
+	return 0;
+}
+
+static int ican3_get_berr_counter(const struct net_device *ndev,
+				  struct can_berr_counter *bec)
+{
+	struct ican3_dev *mod = netdev_priv(ndev);
+	int ret;
+
+	ret = ican3_send_inquiry(mod, INQUIRY_STATUS);
+	if (ret)
+		return ret;
+
+	if (!wait_for_completion_timeout(&mod->buserror_comp, HZ)) {
+		netdev_info(mod->ndev, "%s timed out\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	bec->rxerr = mod->bec.rxerr;
+	bec->txerr = mod->bec.txerr;
+	return 0;
+}
+
+/*
+ * Sysfs Attributes
+ */
+
+static ssize_t ican3_sysfs_show_term(struct device *dev,
+				     struct device_attribute *attr,
+				     char *buf)
+{
+	struct ican3_dev *mod = netdev_priv(to_net_dev(dev));
+	int ret;
+
+	ret = ican3_send_inquiry(mod, INQUIRY_TERMINATION);
+	if (ret)
+		return ret;
+
+	if (!wait_for_completion_timeout(&mod->termination_comp, HZ)) {
+		netdev_info(mod->ndev, "%s timed out\n", __func__);
+		return -ETIMEDOUT;
+	}
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", mod->termination_enabled);
+}
+
+static ssize_t ican3_sysfs_set_term(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t count)
+{
+	struct ican3_dev *mod = netdev_priv(to_net_dev(dev));
+	unsigned long enable;
+	int ret;
+
+	if (kstrtoul(buf, 0, &enable))
+		return -EINVAL;
+
+	ret = ican3_set_termination(mod, enable);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static DEVICE_ATTR(termination, S_IWUSR | S_IRUGO, ican3_sysfs_show_term,
+						   ican3_sysfs_set_term);
+
+static struct attribute *ican3_sysfs_attrs[] = {
+	&dev_attr_termination.attr,
+	NULL,
+};
+
+static struct attribute_group ican3_sysfs_attr_group = {
+	.attrs = ican3_sysfs_attrs,
+};
+
+/*
+ * PCI Subsystem
+ */
+
+static int ican3_probe(struct platform_device *pdev)
+{
+	struct janz_platform_data *pdata;
+	struct net_device *ndev;
+	struct ican3_dev *mod;
+	struct resource *res;
+	struct device *dev;
+	int ret;
+
+	pdata = dev_get_platdata(&pdev->dev);
+	if (!pdata)
+		return -ENXIO;
+
+	dev_dbg(&pdev->dev, "probe: module number %d\n", pdata->modno);
+
+	/* save the struct device for printing */
+	dev = &pdev->dev;
+
+	/* allocate the CAN device and private data */
+	ndev = alloc_candev(sizeof(*mod), 0);
+	if (!ndev) {
+		dev_err(dev, "unable to allocate CANdev\n");
+		ret = -ENOMEM;
+		goto out_return;
+	}
+
+	platform_set_drvdata(pdev, ndev);
+	mod = netdev_priv(ndev);
+	mod->ndev = ndev;
+	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);
+
+	/* setup device-specific sysfs attributes */
+	ndev->sysfs_groups[0] = &ican3_sysfs_attr_group;
+
+	/* the first unallocated page in the DPM is 9 */
+	mod->free_page = DPM_FREE_START;
+
+	ndev->netdev_ops = &ican3_netdev_ops;
+	ndev->flags |= IFF_ECHO;
+	SET_NETDEV_DEV(ndev, &pdev->dev);
+
+	mod->can.clock.freq = ICAN3_CAN_CLOCK;
+	mod->can.bittiming_const = &ican3_bittiming_const;
+	mod->can.do_set_bittiming = ican3_set_bittiming;
+	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_ONE_SHOT;
+
+	/* find our IRQ number */
+	mod->irq = platform_get_irq(pdev, 0);
+	if (mod->irq < 0) {
+		dev_err(dev, "IRQ line not found\n");
+		ret = -ENODEV;
+		goto out_free_ndev;
+	}
+
+	ndev->irq = mod->irq;
+
+	/* get access to the MODULbus registers for this module */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(dev, "MODULbus registers not found\n");
+		ret = -ENODEV;
+		goto out_free_ndev;
+	}
+
+	mod->dpm = ioremap(res->start, resource_size(res));
+	if (!mod->dpm) {
+		dev_err(dev, "MODULbus registers not ioremap\n");
+		ret = -ENOMEM;
+		goto out_free_ndev;
+	}
+
+	mod->dpmctrl = mod->dpm + DPM_PAGE_SIZE;
+
+	/* get access to the control registers for this module */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res) {
+		dev_err(dev, "CONTROL registers not found\n");
+		ret = -ENODEV;
+		goto out_iounmap_dpm;
+	}
+
+	mod->ctrl = ioremap(res->start, resource_size(res));
+	if (!mod->ctrl) {
+		dev_err(dev, "CONTROL registers not ioremap\n");
+		ret = -ENOMEM;
+		goto out_iounmap_dpm;
+	}
+
+	/* disable our IRQ, then hookup the IRQ handler */
+	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
+	ret = request_irq(mod->irq, ican3_irq, IRQF_SHARED, DRV_NAME, mod);
+	if (ret) {
+		dev_err(dev, "unable to request IRQ\n");
+		goto out_iounmap_ctrl;
+	}
+
+	/* reset and initialize the CAN controller into fast mode */
+	napi_enable(&mod->napi);
+	ret = ican3_startup_module(mod);
+	if (ret) {
+		dev_err(dev, "%s: unable to start CANdev\n", __func__);
+		goto out_free_irq;
+	}
+
+	/* register with the Linux CAN layer */
+	ret = register_candev(ndev);
+	if (ret) {
+		dev_err(dev, "%s: unable to register CANdev\n", __func__);
+		goto out_free_irq;
+	}
+
+	dev_info(dev, "module %d: registered CAN device\n", pdata->modno);
+	return 0;
+
+out_free_irq:
+	napi_disable(&mod->napi);
+	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
+	free_irq(mod->irq, mod);
+out_iounmap_ctrl:
+	iounmap(mod->ctrl);
+out_iounmap_dpm:
+	iounmap(mod->dpm);
+out_free_ndev:
+	free_candev(ndev);
+out_return:
+	return ret;
+}
+
+static int ican3_remove(struct platform_device *pdev)
+{
+	struct net_device *ndev = platform_get_drvdata(pdev);
+	struct ican3_dev *mod = netdev_priv(ndev);
+
+	/* unregister the netdevice, stop interrupts */
+	unregister_netdev(ndev);
+	napi_disable(&mod->napi);
+	iowrite8(1 << mod->num, &mod->ctrl->int_disable);
+	free_irq(mod->irq, mod);
+
+	/* put the module into reset */
+	ican3_shutdown_module(mod);
+
+	/* unmap all registers */
+	iounmap(mod->ctrl);
+	iounmap(mod->dpm);
+
+	free_candev(ndev);
+
+	return 0;
+}
+
+static struct platform_driver ican3_driver = {
+	.driver		= {
+		.name	= DRV_NAME,
+	},
+	.probe		= ican3_probe,
+	.remove		= ican3_remove,
+};
+
+module_platform_driver(ican3_driver);
+
+MODULE_AUTHOR("Ira W. Snyder <iws@ovro.caltech.edu>");
+MODULE_DESCRIPTION("Janz MODULbus VMOD-ICAN3 Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:janz-ican3");