// SPDX-License-Identifier: GPL-2.0-or-later/* * PL-2301/2302 USB host-to-host link 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>  /* * Prolific PL-2301/PL-2302 driver ... http://www.prolific.com.tw/ * * The protocol and handshaking used here should be bug-compatible * with the Linux 2.2 "plusb" driver, by Deti Fliegl. * * HEADS UP:  this handshaking isn't all that robust.  This driver * gets confused easily if you unplug one end of the cable then * try to connect it again; you'll need to restart both ends. The * "naplink" software (used by some PlayStation/2 developers) does * the handshaking much better!   Also, sometimes this hardware * seems to get wedged under load.  Prolific docs are weak, and * don't identify differences between PL2301 and PL2302, much less * anything to explain the different PL2302 versions observed. * * NOTE:  pl2501 has several modes, including pl2301 and pl2302 * compatibility.   Some docs suggest the difference between 2301 * and 2302 is only to make MS-Windows use a different driver... * * pl25a1 glue based on patch from Tony Gibbs.  Prolific "docs" on * this chip are as usual incomplete about what control messages * are supported. */ /* * Bits 0-4 can be used for software handshaking; they're set from * one end, cleared from the other, "read" with the interrupt byte. */#define	PL_S_EN		(1<<7)		/* (feature only) suspend enable *//* reserved bit -- rx ready (6) ? */#define	PL_TX_READY	(1<<5)		/* (interrupt only) transmit ready */#define	PL_RESET_OUT	(1<<4)		/* reset output pipe */#define	PL_RESET_IN	(1<<3)		/* reset input pipe */#define	PL_TX_C		(1<<2)		/* transmission complete */#define	PL_TX_REQ	(1<<1)		/* transmission received */#define	PL_PEER_E	(1<<0)		/* peer exists */ static inline intpl_vendor_req(struct usbnet *dev, u8 req, u8 val, u8 index){	return usbnet_write_cmd(dev, req, USB_TYPE_VENDOR | USB_RECIP_DEVICE,				val, index, NULL, 0);} static inline intpl_set_QuickLink_features(struct usbnet *dev, int val){	return pl_vendor_req(dev, 3, (u8) val, 0);} static int pl_reset(struct usbnet *dev){	int status; 	/* some units seem to need this reset, others reject it utterly.	 * FIXME be more like "naplink" or windows drivers.	 */	status = pl_set_QuickLink_features(dev,		PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);	if (status != 0 && netif_msg_probe(dev))		netif_dbg(dev, link, dev->net, "pl_reset --> %d\n", status);	return 0;} static const struct driver_info	prolific_info = {	.description =	"Prolific PL-2301/PL-2302/PL-25A1/PL-27A1",	.flags =	FLAG_POINTTOPOINT | FLAG_NO_SETINT,		/* some PL-2302 versions seem to fail usb_set_interface() */	.reset =	pl_reset,};  /*-------------------------------------------------------------------------*/ /* * Proilific's name won't normally be on the cables, and * may not be on the device. */ static const struct usb_device_id	products [] = { /* full speed cables */{	USB_DEVICE(0x067b, 0x0000),	// PL-2301	.driver_info =	(unsigned long) &prolific_info,}, {	USB_DEVICE(0x067b, 0x0001),	// PL-2302	.driver_info =	(unsigned long) &prolific_info,}, /* high speed cables */{	USB_DEVICE(0x067b, 0x25a1),     /* PL-25A1, no eeprom */	.driver_info =  (unsigned long) &prolific_info,}, {	USB_DEVICE(0x050d, 0x258a),     /* Belkin F5U258/F5U279 (PL-25A1) */	.driver_info =  (unsigned long) &prolific_info,}, {	USB_DEVICE(0x3923, 0x7825),     /* National Instruments USB					 * Host-to-Host Cable					 */	.driver_info =  (unsigned long) &prolific_info, }, /* super speed cables */{	USB_DEVICE(0x067b, 0x27a1),     /* PL-27A1, no eeprom					 * also: goobay Active USB 3.0					 * Data Link,					 * Unitek Y-3501					 */	.driver_info =  (unsigned long) &prolific_info,}, 	{ },		// END};MODULE_DEVICE_TABLE(usb, products); static struct usb_driver plusb_driver = {	.name =		"plusb",	.id_table =	products,	.probe =	usbnet_probe,	.disconnect =	usbnet_disconnect,	.suspend =	usbnet_suspend,	.resume =	usbnet_resume,	.disable_hub_initiated_lpm = 1,}; module_usb_driver(plusb_driver); MODULE_AUTHOR("David Brownell");MODULE_DESCRIPTION("Prolific PL-2301/2302/25A1/27A1 USB Host to Host Link Driver");MODULE_LICENSE("GPL");