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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* GeneSys GL620USB-A based links
* Copyright (C) 2001 by Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
* Copyright (C) 2001 by Stanislav Brabec <utx@penguin.cz>
*/
// #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/gfp.h>
/*
* GeneSys GL620USB-A (www.genesyslogic.com.tw)
*
* ... should partially interop with the Win32 driver for this hardware.
* The GeneSys docs imply there's some NDIS issue motivating this framing.
*
* Some info from GeneSys:
* - GL620USB-A is full duplex; GL620USB is only half duplex for bulk.
* (Some cables, like the BAFO-100c, use the half duplex version.)
* - For the full duplex model, the low bit of the version code says
* which side is which ("left/right").
* - For the half duplex type, a control/interrupt handshake settles
* the transfer direction. (That's disabled here, partially coded.)
* A control URB would block until other side writes an interrupt.
*
* Original code from Jiun-Jie Huang <huangjj@genesyslogic.com.tw>
* and merged into "usbnet" by Stanislav Brabec <utx@penguin.cz>.
*/
// control msg write command
#define GENELINK_CONNECT_WRITE 0xF0
// interrupt pipe index
#define GENELINK_INTERRUPT_PIPE 0x03
// interrupt read buffer size
#define INTERRUPT_BUFSIZE 0x08
// interrupt pipe interval value
#define GENELINK_INTERRUPT_INTERVAL 0x10
// max transmit packet number per transmit
#define GL_MAX_TRANSMIT_PACKETS 32
// max packet length
#define GL_MAX_PACKET_LEN 1514
// max receive buffer size
#define GL_RCV_BUF_SIZE \
(((GL_MAX_PACKET_LEN + 4) * GL_MAX_TRANSMIT_PACKETS) + 4)
struct gl_packet {
__le32 packet_length;
char packet_data [1];
};
struct gl_header {
__le32 packet_count;
struct gl_packet packets;
};
static int genelink_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
{
struct gl_header *header;
struct gl_packet *packet;
struct sk_buff *gl_skb;
u32 size;
u32 count;
/* This check is no longer done by usbnet */
if (skb->len < dev->net->hard_header_len)
return 0;
header = (struct gl_header *) skb->data;
// get the packet count of the received skb
count = le32_to_cpu(header->packet_count);
if (count > GL_MAX_TRANSMIT_PACKETS) {
netdev_dbg(dev->net,
"genelink: invalid received packet count %u\n",
count);
return 0;
}
// set the current packet pointer to the first packet
packet = &header->packets;
// decrement the length for the packet count size 4 bytes
skb_pull(skb, 4);
while (count > 1) {
// get the packet length
size = le32_to_cpu(packet->packet_length);
// this may be a broken packet
if (size > GL_MAX_PACKET_LEN) {
netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
size);
return 0;
}
// allocate the skb for the individual packet
gl_skb = alloc_skb(size, GFP_ATOMIC);
if (gl_skb) {
// copy the packet data to the new skb
skb_put_data(gl_skb, packet->packet_data, size);
usbnet_skb_return(dev, gl_skb);
}
// advance to the next packet
packet = (struct gl_packet *)&packet->packet_data[size];
count--;
// shift the data pointer to the next gl_packet
skb_pull(skb, size + 4);
}
// skip the packet length field 4 bytes
skb_pull(skb, 4);
if (skb->len > GL_MAX_PACKET_LEN) {
netdev_dbg(dev->net, "genelink: invalid rx length %d\n",
skb->len);
return 0;
}
return 1;
}
static struct sk_buff *
genelink_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags)
{
int padlen;
int length = skb->len;
int headroom = skb_headroom(skb);
int tailroom = skb_tailroom(skb);
__le32 *packet_count;
__le32 *packet_len;
// FIXME: magic numbers, bleech
padlen = ((skb->len + (4 + 4*1)) % 64) ? 0 : 1;
if ((!skb_cloned(skb))
&& ((headroom + tailroom) >= (padlen + (4 + 4*1)))) {
if ((headroom < (4 + 4*1)) || (tailroom < padlen)) {
skb->data = memmove(skb->head + (4 + 4*1),
skb->data, skb->len);
skb_set_tail_pointer(skb, skb->len);
}
} else {
struct sk_buff *skb2;
skb2 = skb_copy_expand(skb, (4 + 4*1) , padlen, flags);
dev_kfree_skb_any(skb);
skb = skb2;
if (!skb)
return NULL;
}
// attach the packet count to the header
packet_count = skb_push(skb, (4 + 4 * 1));
packet_len = packet_count + 1;
*packet_count = cpu_to_le32(1);
*packet_len = cpu_to_le32(length);
// add padding byte
if ((skb->len % dev->maxpacket) == 0)
skb_put(skb, 1);
return skb;
}
static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
{
dev->hard_mtu = GL_RCV_BUF_SIZE;
dev->net->hard_header_len += 4;
dev->in = usb_rcvbulkpipe(dev->udev, dev->driver_info->in);
dev->out = usb_sndbulkpipe(dev->udev, dev->driver_info->out);
return 0;
}
static const struct driver_info genelink_info = {
.description = "Genesys GeneLink",
.flags = FLAG_POINTTOPOINT | FLAG_FRAMING_GL | FLAG_NO_SETINT,
.bind = genelink_bind,
.rx_fixup = genelink_rx_fixup,
.tx_fixup = genelink_tx_fixup,
.in = 1, .out = 2,
#ifdef GENELINK_ACK
.check_connect =genelink_check_connect,
#endif
};
static const struct usb_device_id products [] = {
{
USB_DEVICE(0x05e3, 0x0502), // GL620USB-A
.driver_info = (unsigned long) &genelink_info,
},
/* NOT: USB_DEVICE(0x05e3, 0x0501), // GL620USB
* that's half duplex, not currently supported
*/
{ }, // END
};
MODULE_DEVICE_TABLE(usb, products);
static struct usb_driver gl620a_driver = {
.name = "gl620a",
.id_table = products,
.probe = usbnet_probe,
.disconnect = usbnet_disconnect,
.suspend = usbnet_suspend,
.resume = usbnet_resume,
.disable_hub_initiated_lpm = 1,
};
module_usb_driver(gl620a_driver);
MODULE_AUTHOR("Jiun-Jie Huang");
MODULE_DESCRIPTION("GL620-USB-A Host-to-Host Link cables");
MODULE_LICENSE("GPL");
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