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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Net1080 based USB host-to-host cables
* Copyright (C) 2000-2005 by David Brownell
*/
// #define DEBUG // error path messages, extra info
// #define VERBOSE // more; success messages
#include <linux/module.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 <linux/usb/usbnet.h>
#include <linux/slab.h>
#include <asm/unaligned.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;
} __packed;
#define PAD_BYTE ((unsigned char)0xAC)
struct nc_trailer {
__le16 packet_id;
} __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 = usbnet_read_cmd(dev, req,
USB_DIR_IN | USB_TYPE_VENDOR |
USB_RECIP_DEVICE,
0, regnum, retval_ptr,
sizeof *retval_ptr);
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)
{
usbnet_write_cmd(dev, req,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
value, regnum, NULL, 0);
}
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)
return;
netdev_dbg(dev->net, "registers:\n");
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)
netdev_dbg(dev->net, "reg [0x%x] ==> error %d\n",
reg, retval);
else
netdev_dbg(dev->net, "reg [0x%x] = 0x%x\n", 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)
{
netif_dbg(dev, link, dev->net,
"net1080 %s-%s usbctl 0x%x:%s%s%s%s%s; this%s%s; other%s%s; r/o 0x%x\n",
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_THIS) ? " FLUSH" : "",
(usbctl & USBCTL_DISCONN_THIS) ? " DIS" : "",
(usbctl & USBCTL_FLUSH_OTHER) ? " FLUSH" : "",
(usbctl & USBCTL_DISCONN_OTHER) ? " 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)
{
netif_dbg(dev, link, dev->net,
"net1080 %s-%s status 0x%x: this (%c) PKT=%d%s%s%s; other PKT=%d%s%s%s; unspec 0x%x\n",
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_OTHER(ttl) (0x00ff & (ttl >> 8))
#define MK_TTL(this,other) ((u16)(((other)<<8)|(0x00ff&(this))))
/*-------------------------------------------------------------------------*/
static int net1080_reset(struct usbnet *dev)
{
u16 usbctl, status, ttl;
u16 vp;
int retval;
// nc_dump_registers(dev);
if ((retval = nc_register_read(dev, REG_STATUS, &vp)) < 0) {
netdev_dbg(dev->net, "can't read %s-%s status: %d\n",
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) {
netdev_dbg(dev->net, "can't read USBCTL, %d\n", 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) {
netdev_dbg(dev->net, "can't read TTL, %d\n", retval);
goto done;
}
ttl = vp;
nc_register_write(dev, REG_TTL,
MK_TTL(NC_READ_TTL_MS, TTL_OTHER(ttl)) );
netdev_dbg(dev->net, "assigned TTL, %d ms\n", NC_READ_TTL_MS);
netif_info(dev, link, dev->net, "port %c, peer %sconnected\n",
(status & STATUS_PORT_A) ? 'A' : 'B',
(status & STATUS_CONN_OTHER) ? "" : "dis");
retval = 0;
done:
return retval;
}
static int net1080_check_connect(struct usbnet *dev)
{
int retval;
u16 status;
u16 vp;
retval = nc_register_read(dev, REG_STATUS, &vp);
status = vp;
if (retval != 0) {
netdev_dbg(dev->net, "net1080_check_conn read - %d\n", retval);
return retval;
}
if ((status & STATUS_CONN_OTHER) != STATUS_CONN_OTHER)
return -ENOLINK;
return 0;
}
static void nc_ensure_sync(struct usbnet *dev)
{
if (++dev->frame_errors <= 5)
return;
if (usbnet_write_cmd_async(dev, REQUEST_REGISTER,
USB_DIR_OUT | USB_TYPE_VENDOR |
USB_RECIP_DEVICE,
USBCTL_FLUSH_THIS |
USBCTL_FLUSH_OTHER,
REG_USBCTL, NULL, 0))
return;
netif_dbg(dev, rx_err, dev->net,
"flush net1080; too many framing errors\n");
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;
/* This check is no longer done by usbnet */
if (skb->len < dev->net->hard_header_len)
return 0;
if (!(skb->len & 0x01)) {
netdev_dbg(dev->net, "rx framesize %d range %d..%d mtu %d\n",
skb->len, dev->net->hard_header_len, dev->hard_mtu,
dev->net->mtu);
dev->net->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->net->stats.rx_frame_errors++;
netdev_dbg(dev->net, "packet too big, %d\n", packet_len);
nc_ensure_sync(dev);
return 0;
} else if (hdr_len < MIN_HEADER) {
dev->net->stats.rx_frame_errors++;
netdev_dbg(dev->net, "header too short, %d\n", hdr_len);
nc_ensure_sync(dev);
return 0;
} else if (hdr_len > MIN_HEADER) {
// out of band data for us?
netdev_dbg(dev->net, "header OOB, %d bytes\n", 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->net->stats.rx_frame_errors++;
netdev_dbg(dev->net, "bad pad\n");
return 0;
}
skb_trim(skb, skb->len - 1);
}
if (skb->len != packet_len) {
dev->net->stats.rx_frame_errors++;
netdev_dbg(dev->net, "bad packet len %d (expected %d)\n",
skb->len, packet_len);
nc_ensure_sync(dev);
return 0;
}
if (header->packet_id != get_unaligned(&trailer->packet_id)) {
dev->net->stats.rx_fifo_errors++;
netdev_dbg(dev->net, "(2+ dropped) rx packet_id mismatch 0x%x 0x%x\n",
le16_to_cpu(header->packet_id),
le16_to_cpu(trailer->packet_id));
return 0;
}
#if 0
netdev_dbg(dev->net, "frame <rx h %d p %d id %d\n", 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, gfp_t flags)
{
struct sk_buff *skb2;
struct nc_header *header = NULL;
struct nc_trailer *trailer = NULL;
int padlen = sizeof (struct nc_trailer);
int len = skb->len;
if (!((len + padlen + sizeof (struct nc_header)) & 0x01))
padlen++;
if (!skb_cloned(skb)) {
int headroom = skb_headroom(skb);
int tailroom = skb_tailroom(skb);
if (padlen <= tailroom &&
sizeof(struct nc_header) <= headroom)
/* There's enough head and tail room */
goto encapsulate;
if ((sizeof (struct nc_header) + padlen) <
(headroom + tailroom)) {
/* There's enough total room, so just readjust */
skb->data = memmove(skb->head
+ sizeof (struct nc_header),
skb->data, skb->len);
skb_set_tail_pointer(skb, len);
goto encapsulate;
}
}
/* Create a new skb to use with the correct size */
skb2 = skb_copy_expand(skb,
sizeof (struct nc_header),
padlen,
flags);
dev_kfree_skb_any(skb);
if (!skb2)
return skb2;
skb = skb2;
encapsulate:
/* header first */
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_u8(skb, PAD_BYTE);
trailer = skb_put(skb, sizeof *trailer);
put_unaligned(header->packet_id, &trailer->packet_id);
#if 0
netdev_dbg(dev->net, "frame >tx h %d p %d id %d\n",
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_POINTTOPOINT | 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 = {
.name = "net1080",
.id_table = products,
.probe = usbnet_probe,
.disconnect = usbnet_disconnect,
.suspend = usbnet_suspend,
.resume = usbnet_resume,
.disable_hub_initiated_lpm = 1,
};
module_usb_driver(net1080_driver);
MODULE_AUTHOR("David Brownell");
MODULE_DESCRIPTION("NetChip 1080 based USB Host-to-Host Links");
MODULE_LICENSE("GPL");
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