[PATCH] USB: usbnet (4/9) module for net1080 cables

As with the "cdc_subset" and "asix" drivers, this just moves the net1080
support into its one driver module.  In this case there's a small bit of
extra cleanup involved, moving some funky framing logic into the tx_fixup()
routine (resolving a long overdue FIXME).

Minor historical note:  "usbnet" started out as "net1080", then got
generalized to make it easier for other network drivers to reuse the
urb queueing and fault management code here.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 622 insertions, 0 deletions

diff --git a/drivers/usb/net/net1080.c b/drivers/usb/net/net1080.c
new file mode 100644
index 000000000000..a4309c4a491b
--- /dev/null
+++ b/drivers/usb/net/net1080.c
@@ -0,0 +1,622 @@
+/*
+ * Net1080 based USB host-to-host cables
+ * Copyright (C) 2000-2005 by David Brownell
+ *
+ * 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.
+ *
+ * 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
+ */
+
+// #define	DEBUG			// error path messages, extra info
+// #define	VERBOSE			// more; success messages
+
+#include <linux/config.h>
+#ifdef	CONFIG_USB_DEBUG
+#   define DEBUG
+#endif
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <linux/netdevice.h>
+#include <linux/etherdevice.h>
+#include <linux/ethtool.h>
+#include <linux/workqueue.h>
+#include <linux/mii.h>
+#include <linux/usb.h>
+
+#include <asm/unaligned.h>
+
+#include "usbnet.h"
+
+
+/*
+ * Netchip 1080 driver ... http://www.netchip.com
+ * (Sept 2004:  End-of-life announcement has been sent.)
+ * Used in (some) LapLink cables
+ */
+
+#define frame_errors	data[1]
+
+/*
+ * NetChip framing of ethernet packets, supporting additional error
+ * checks for links that may drop bulk packets from inside messages.
+ * Odd USB length == always short read for last usb packet.
+ *	- nc_header
+ *	- Ethernet header (14 bytes)
+ *	- payload
+ *	- (optional padding byte, if needed so length becomes odd)
+ *	- nc_trailer
+ *
+ * This framing is to be avoided for non-NetChip devices.
+ */
+
+struct nc_header {		// packed:
+	__le16	hdr_len;		// sizeof nc_header (LE, all)
+	__le16	packet_len;		// payload size (including ethhdr)
+	__le16	packet_id;		// detects dropped packets
+#define MIN_HEADER	6
+
+	// all else is optional, and must start with:
+	// __le16	vendorId;	// from usb-if
+	// __le16	productId;
+} __attribute__((__packed__));
+
+#define	PAD_BYTE	((unsigned char)0xAC)
+
+struct nc_trailer {
+	__le16	packet_id;
+} __attribute__((__packed__));
+
+// packets may use FLAG_FRAMING_NC and optional pad
+#define FRAMED_SIZE(mtu) (sizeof (struct nc_header) \
+				+ sizeof (struct ethhdr) \
+				+ (mtu) \
+				+ 1 \
+				+ sizeof (struct nc_trailer))
+
+#define MIN_FRAMED	FRAMED_SIZE(0)
+
+/* packets _could_ be up to 64KB... */
+#define NC_MAX_PACKET	32767
+
+
+/*
+ * Zero means no timeout; else, how long a 64 byte bulk packet may be queued
+ * before the hardware drops it.  If that's done, the driver will need to
+ * frame network packets to guard against the dropped USB packets.  The win32
+ * driver sets this for both sides of the link.
+ */
+#define	NC_READ_TTL_MS	((u8)255)	// ms
+
+/*
+ * We ignore most registers and EEPROM contents.
+ */
+#define	REG_USBCTL	((u8)0x04)
+#define REG_TTL		((u8)0x10)
+#define REG_STATUS	((u8)0x11)
+
+/*
+ * Vendor specific requests to read/write data
+ */
+#define	REQUEST_REGISTER	((u8)0x10)
+#define	REQUEST_EEPROM		((u8)0x11)
+
+static int
+nc_vendor_read(struct usbnet *dev, u8 req, u8 regnum, u16 *retval_ptr)
+{
+	int status = usb_control_msg(dev->udev,
+		usb_rcvctrlpipe(dev->udev, 0),
+		req,
+		USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		0, regnum,
+		retval_ptr, sizeof *retval_ptr,
+		USB_CTRL_GET_TIMEOUT);
+	if (status > 0)
+		status = 0;
+	if (!status)
+		le16_to_cpus(retval_ptr);
+	return status;
+}
+
+static inline int
+nc_register_read(struct usbnet *dev, u8 regnum, u16 *retval_ptr)
+{
+	return nc_vendor_read(dev, REQUEST_REGISTER, regnum, retval_ptr);
+}
+
+// no retval ... can become async, usable in_interrupt()
+static void
+nc_vendor_write(struct usbnet *dev, u8 req, u8 regnum, u16 value)
+{
+	usb_control_msg(dev->udev,
+		usb_sndctrlpipe(dev->udev, 0),
+		req,
+		USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
+		value, regnum,
+		NULL, 0,			// data is in setup packet
+		USB_CTRL_SET_TIMEOUT);
+}
+
+static inline void
+nc_register_write(struct usbnet *dev, u8 regnum, u16 value)
+{
+	nc_vendor_write(dev, REQUEST_REGISTER, regnum, value);
+}
+
+
+#if 0
+static void nc_dump_registers(struct usbnet *dev)
+{
+	u8	reg;
+	u16	*vp = kmalloc(sizeof (u16));
+
+	if (!vp) {
+		dbg("no memory?");
+		return;
+	}
+
+	dbg("%s registers:", dev->net->name);
+	for (reg = 0; reg < 0x20; reg++) {
+		int retval;
+
+		// reading some registers is trouble
+		if (reg >= 0x08 && reg <= 0xf)
+			continue;
+		if (reg >= 0x12 && reg <= 0x1e)
+			continue;
+
+		retval = nc_register_read(dev, reg, vp);
+		if (retval < 0)
+			dbg("%s reg [0x%x] ==> error %d",
+				dev->net->name, reg, retval);
+		else
+			dbg("%s reg [0x%x] = 0x%x",
+				dev->net->name, reg, *vp);
+	}
+	kfree(vp);
+}
+#endif
+
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Control register
+ */
+
+#define	USBCTL_WRITABLE_MASK	0x1f0f
+// bits 15-13 reserved, r/o
+#define	USBCTL_ENABLE_LANG	(1 << 12)
+#define	USBCTL_ENABLE_MFGR	(1 << 11)
+#define	USBCTL_ENABLE_PROD	(1 << 10)
+#define	USBCTL_ENABLE_SERIAL	(1 << 9)
+#define	USBCTL_ENABLE_DEFAULTS	(1 << 8)
+// bits 7-4 reserved, r/o
+#define	USBCTL_FLUSH_OTHER	(1 << 3)
+#define	USBCTL_FLUSH_THIS	(1 << 2)
+#define	USBCTL_DISCONN_OTHER	(1 << 1)
+#define	USBCTL_DISCONN_THIS	(1 << 0)
+
+static inline void nc_dump_usbctl(struct usbnet *dev, u16 usbctl)
+{
+	if (!netif_msg_link(dev))
+		return;
+	devdbg(dev, "net1080 %s-%s usbctl 0x%x:%s%s%s%s%s;"
+			" this%s%s;"
+			" other%s%s; r/o 0x%x",
+		dev->udev->bus->bus_name, dev->udev->devpath,
+		usbctl,
+		(usbctl & USBCTL_ENABLE_LANG) ? " lang" : "",
+		(usbctl & USBCTL_ENABLE_MFGR) ? " mfgr" : "",
+		(usbctl & USBCTL_ENABLE_PROD) ? " prod" : "",
+		(usbctl & USBCTL_ENABLE_SERIAL) ? " serial" : "",
+		(usbctl & USBCTL_ENABLE_DEFAULTS) ? " defaults" : "",
+
+		(usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
+		(usbctl & USBCTL_DISCONN_OTHER) ? " DIS" : "",
+		(usbctl & USBCTL_FLUSH_THIS) ? " FLUSH" : "",
+		(usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
+		usbctl & ~USBCTL_WRITABLE_MASK
+		);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * Status register
+ */
+
+#define	STATUS_PORT_A		(1 << 15)
+
+#define	STATUS_CONN_OTHER	(1 << 14)
+#define	STATUS_SUSPEND_OTHER	(1 << 13)
+#define	STATUS_MAILBOX_OTHER	(1 << 12)
+#define	STATUS_PACKETS_OTHER(n)	(((n) >> 8) && 0x03)
+
+#define	STATUS_CONN_THIS	(1 << 6)
+#define	STATUS_SUSPEND_THIS	(1 << 5)
+#define	STATUS_MAILBOX_THIS	(1 << 4)
+#define	STATUS_PACKETS_THIS(n)	(((n) >> 0) && 0x03)
+
+#define	STATUS_UNSPEC_MASK	0x0c8c
+#define	STATUS_NOISE_MASK 	((u16)~(0x0303|STATUS_UNSPEC_MASK))
+
+
+static inline void nc_dump_status(struct usbnet *dev, u16 status)
+{
+	if (!netif_msg_link(dev))
+		return;
+	devdbg(dev, "net1080 %s-%s status 0x%x:"
+			" this (%c) PKT=%d%s%s%s;"
+			" other PKT=%d%s%s%s; unspec 0x%x",
+		dev->udev->bus->bus_name, dev->udev->devpath,
+		status,
+
+		// XXX the packet counts don't seem right
+		// (1 at reset, not 0); maybe UNSPEC too
+
+		(status & STATUS_PORT_A) ? 'A' : 'B',
+		STATUS_PACKETS_THIS(status),
+		(status & STATUS_CONN_THIS) ? " CON" : "",
+		(status & STATUS_SUSPEND_THIS) ? " SUS" : "",
+		(status & STATUS_MAILBOX_THIS) ? " MBOX" : "",
+
+		STATUS_PACKETS_OTHER(status),
+		(status & STATUS_CONN_OTHER) ? " CON" : "",
+		(status & STATUS_SUSPEND_OTHER) ? " SUS" : "",
+		(status & STATUS_MAILBOX_OTHER) ? " MBOX" : "",
+
+		status & STATUS_UNSPEC_MASK
+		);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * TTL register
+ */
+
+#define	TTL_THIS(ttl)	(0x00ff & ttl)
+#define	TTL_OTHER(ttl)	(0x00ff & (ttl >> 8))
+#define MK_TTL(this,other)	((u16)(((other)<<8)|(0x00ff&(this))))
+
+static inline void nc_dump_ttl(struct usbnet *dev, u16 ttl)
+{
+	if (netif_msg_link(dev))
+		devdbg(dev, "net1080 %s-%s ttl 0x%x this = %d, other = %d",
+			dev->udev->bus->bus_name, dev->udev->devpath,
+			ttl, TTL_THIS(ttl), TTL_OTHER(ttl));
+}
+
+/*-------------------------------------------------------------------------*/
+
+static int net1080_reset(struct usbnet *dev)
+{
+	u16		usbctl, status, ttl;
+	u16		*vp = kmalloc(sizeof (u16), GFP_KERNEL);
+	int		retval;
+
+	if (!vp)
+		return -ENOMEM;
+
+	// nc_dump_registers(dev);
+
+	if ((retval = nc_register_read(dev, REG_STATUS, vp)) < 0) {
+		dbg("can't read %s-%s status: %d",
+			dev->udev->bus->bus_name, dev->udev->devpath, retval);
+		goto done;
+	}
+	status = *vp;
+	nc_dump_status(dev, status);
+
+	if ((retval = nc_register_read(dev, REG_USBCTL, vp)) < 0) {
+		dbg("can't read USBCTL, %d", retval);
+		goto done;
+	}
+	usbctl = *vp;
+	nc_dump_usbctl(dev, usbctl);
+
+	nc_register_write(dev, REG_USBCTL,
+			USBCTL_FLUSH_THIS | USBCTL_FLUSH_OTHER);
+
+	if ((retval = nc_register_read(dev, REG_TTL, vp)) < 0) {
+		dbg("can't read TTL, %d", retval);
+		goto done;
+	}
+	ttl = *vp;
+	// nc_dump_ttl(dev, ttl);
+
+	nc_register_write(dev, REG_TTL,
+			MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
+	dbg("%s: assigned TTL, %d ms", dev->net->name, NC_READ_TTL_MS);
+
+	if (netif_msg_link(dev))
+		devinfo(dev, "port %c, peer %sconnected",
+			(status & STATUS_PORT_A) ? 'A' : 'B',
+			(status & STATUS_CONN_OTHER) ? "" : "dis"
+			);
+	retval = 0;
+
+done:
+	kfree(vp);
+	return retval;
+}
+
+static int net1080_check_connect(struct usbnet *dev)
+{
+	int			retval;
+	u16			status;
+	u16			*vp = kmalloc(sizeof (u16), GFP_KERNEL);
+
+	if (!vp)
+		return -ENOMEM;
+	retval = nc_register_read(dev, REG_STATUS, vp);
+	status = *vp;
+	kfree(vp);
+	if (retval != 0) {
+		dbg("%s net1080_check_conn read - %d", dev->net->name, retval);
+		return retval;
+	}
+	if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
+		return -ENOLINK;
+	return 0;
+}
+
+static void nc_flush_complete(struct urb *urb, struct pt_regs *regs)
+{
+	kfree(urb->context);
+	usb_free_urb(urb);
+}
+
+static void nc_ensure_sync(struct usbnet *dev)
+{
+	dev->frame_errors++;
+	if (dev->frame_errors > 5) {
+		struct urb		*urb;
+		struct usb_ctrlrequest	*req;
+		int			status;
+
+		/* Send a flush */
+		urb = usb_alloc_urb(0, SLAB_ATOMIC);
+		if (!urb)
+			return;
+
+		req = kmalloc(sizeof *req, GFP_ATOMIC);
+		if (!req) {
+			usb_free_urb(urb);
+			return;
+		}
+
+		req->bRequestType = USB_DIR_OUT
+			| USB_TYPE_VENDOR
+			| USB_RECIP_DEVICE;
+		req->bRequest = REQUEST_REGISTER;
+		req->wValue = cpu_to_le16(USBCTL_FLUSH_THIS
+				| USBCTL_FLUSH_OTHER);
+		req->wIndex = cpu_to_le16(REG_USBCTL);
+		req->wLength = cpu_to_le16(0);
+
+		/* queue an async control request, we don't need
+		 * to do anything when it finishes except clean up.
+		 */
+		usb_fill_control_urb(urb, dev->udev,
+			usb_sndctrlpipe(dev->udev, 0),
+			(unsigned char *) req,
+			NULL, 0,
+			nc_flush_complete, req);
+		status = usb_submit_urb(urb, GFP_ATOMIC);
+		if (status) {
+			kfree(req);
+			usb_free_urb(urb);
+			return;
+		}
+
+		if (netif_msg_rx_err(dev))
+			devdbg(dev, "flush net1080; too many framing errors");
+		dev->frame_errors = 0;
+	}
+}
+
+static int net1080_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
+{
+	struct nc_header	*header;
+	struct nc_trailer	*trailer;
+	u16			hdr_len, packet_len;
+
+	if (!(skb->len & 0x01)) {
+#ifdef DEBUG
+		struct net_device	*net = dev->net;
+		dbg("rx framesize %d range %d..%d mtu %d", skb->len,
+			net->hard_header_len, dev->hard_mtu, net->mtu);
+#endif
+		dev->stats.rx_frame_errors++;
+		nc_ensure_sync(dev);
+		return 0;
+	}
+
+	header = (struct nc_header *) skb->data;
+	hdr_len = le16_to_cpup(&header->hdr_len);
+	packet_len = le16_to_cpup(&header->packet_len);
+	if (FRAMED_SIZE(packet_len) > NC_MAX_PACKET) {
+		dev->stats.rx_frame_errors++;
+		dbg("packet too big, %d", packet_len);
+		nc_ensure_sync(dev);
+		return 0;
+	} else if (hdr_len < MIN_HEADER) {
+		dev->stats.rx_frame_errors++;
+		dbg("header too short, %d", hdr_len);
+		nc_ensure_sync(dev);
+		return 0;
+	} else if (hdr_len > MIN_HEADER) {
+		// out of band data for us?
+		dbg("header OOB, %d bytes", hdr_len - MIN_HEADER);
+		nc_ensure_sync(dev);
+		// switch (vendor/product ids) { ... }
+	}
+	skb_pull(skb, hdr_len);
+
+	trailer = (struct nc_trailer *)
+		(skb->data + skb->len - sizeof *trailer);
+	skb_trim(skb, skb->len - sizeof *trailer);
+
+	if ((packet_len & 0x01) == 0) {
+		if (skb->data [packet_len] != PAD_BYTE) {
+			dev->stats.rx_frame_errors++;
+			dbg("bad pad");
+			return 0;
+		}
+		skb_trim(skb, skb->len - 1);
+	}
+	if (skb->len != packet_len) {
+		dev->stats.rx_frame_errors++;
+		dbg("bad packet len %d (expected %d)",
+			skb->len, packet_len);
+		nc_ensure_sync(dev);
+		return 0;
+	}
+	if (header->packet_id != get_unaligned(&trailer->packet_id)) {
+		dev->stats.rx_fifo_errors++;
+		dbg("(2+ dropped) rx packet_id mismatch 0x%x 0x%x",
+			le16_to_cpu(header->packet_id),
+			le16_to_cpu(trailer->packet_id));
+		return 0;
+	}
+#if 0
+	devdbg(dev, "frame <rx h %d p %d id %d", header->hdr_len,
+		header->packet_len, header->packet_id);
+#endif
+	dev->frame_errors = 0;
+	return 1;
+}
+
+static struct sk_buff *
+net1080_tx_fixup(struct usbnet *dev, struct sk_buff *skb, unsigned flags)
+{
+	int			padlen;
+	struct sk_buff		*skb2;
+	struct nc_header	*header = NULL;
+	struct nc_trailer	*trailer = NULL;
+	int			len = skb->len;
+
+	padlen = ((len + sizeof (struct nc_header)
+			+ sizeof (struct nc_trailer)) & 0x01) ? 0 : 1;
+	if (!skb_cloned(skb)) {
+		int	headroom = skb_headroom(skb);
+		int	tailroom = skb_tailroom(skb);
+
+		if ((padlen + sizeof (struct nc_trailer)) <= tailroom
+			    && sizeof (struct nc_header) <= headroom)
+			/* There's enough head and tail room */
+			goto encapsulate;
+
+		if ((sizeof (struct nc_header) + padlen
+					+ sizeof (struct nc_trailer)) <
+				(headroom + tailroom)) {
+			/* There's enough total room, so just readjust */
+			skb->data = memmove(skb->head
+						+ sizeof (struct nc_header),
+					    skb->data, skb->len);
+			skb->tail = skb->data + len;
+			goto encapsulate;
+		}
+	}
+
+	/* Create a new skb to use with the correct size */
+	skb2 = skb_copy_expand(skb,
+				sizeof (struct nc_header),
+				sizeof (struct nc_trailer) + padlen,
+				flags);
+	dev_kfree_skb_any(skb);
+	if (!skb2)
+		return skb2;
+	skb = skb2;
+
+encapsulate:
+	/* header first */
+	header = (struct nc_header *) skb_push(skb, sizeof *header);
+	header->hdr_len = cpu_to_le16(sizeof (*header));
+	header->packet_len = cpu_to_le16(len);
+	header->packet_id = cpu_to_le16((u16)dev->xid++);
+
+	/* maybe pad; then trailer */
+	if (!((skb->len + sizeof *trailer) & 0x01))
+		*skb_put(skb, 1) = PAD_BYTE;
+	trailer = (struct nc_trailer *) skb_put(skb, sizeof *trailer);
+	put_unaligned(header->packet_id, &trailer->packet_id);
+#if 0
+	devdbg(dev, "frame >tx h %d p %d id %d",
+		header->hdr_len, header->packet_len,
+		header->packet_id);
+#endif
+	return skb;
+}
+
+static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
+{
+	unsigned	extra = sizeof (struct nc_header)
+				+ 1
+				+ sizeof (struct nc_trailer);
+
+	dev->net->hard_header_len += extra;
+	dev->rx_urb_size = dev->net->hard_header_len + dev->net->mtu;
+	dev->hard_mtu = NC_MAX_PACKET;
+	return usbnet_get_endpoints (dev, intf);
+}
+
+static const struct driver_info	net1080_info = {
+	.description =	"NetChip TurboCONNECT",
+	.flags =	FLAG_FRAMING_NC,
+	.bind =		net1080_bind,
+	.reset =	net1080_reset,
+	.check_connect = net1080_check_connect,
+	.rx_fixup =	net1080_rx_fixup,
+	.tx_fixup =	net1080_tx_fixup,
+};
+
+static const struct usb_device_id	products [] = {
+{
+	USB_DEVICE(0x0525, 0x1080),	// NetChip ref design
+	.driver_info =	(unsigned long) &net1080_info,
+}, {
+	USB_DEVICE(0x06D0, 0x0622),	// Laplink Gold
+	.driver_info =	(unsigned long) &net1080_info,
+},
+	{ },		// END
+};
+MODULE_DEVICE_TABLE(usb, products);
+
+static struct usb_driver net1080_driver = {
+	.owner =	THIS_MODULE,
+	.name =		"net1080",
+	.id_table =	products,
+	.probe =	usbnet_probe,
+	.disconnect =	usbnet_disconnect,
+	.suspend =	usbnet_suspend,
+	.resume =	usbnet_resume,
+};
+
+static int __init net1080_init(void)
+{
+ 	return usb_register(&net1080_driver);
+}
+module_init(net1080_init);
+
+static void __exit net1080_exit(void)
+{
+ 	usb_deregister(&net1080_driver);
+}
+module_exit(net1080_exit);
+
+MODULE_AUTHOR("David Brownell");
+MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
+MODULE_LICENSE("GPL");