1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * PL-2301/2302 USB host-to-host link cables
4  * Copyright (C) 2000-2005 by David Brownell
5  */
6 
7 // #define	DEBUG			// error path messages, extra info
8 // #define	VERBOSE			// more; success messages
9 
10 #include <linux/module.h>
11 #include <linux/netdevice.h>
12 #include <linux/etherdevice.h>
13 #include <linux/ethtool.h>
14 #include <linux/workqueue.h>
15 #include <linux/mii.h>
16 #include <linux/usb.h>
17 #include <linux/usb/usbnet.h>
18 
19 
20 /*
21  * Prolific PL-2301/PL-2302 driver ... http://www.prolific.com.tw/
22  *
23  * The protocol and handshaking used here should be bug-compatible
24  * with the Linux 2.2 "plusb" driver, by Deti Fliegl.
25  *
26  * HEADS UP:  this handshaking isn't all that robust.  This driver
27  * gets confused easily if you unplug one end of the cable then
28  * try to connect it again; you'll need to restart both ends. The
29  * "naplink" software (used by some PlayStation/2 developers) does
30  * the handshaking much better!   Also, sometimes this hardware
31  * seems to get wedged under load.  Prolific docs are weak, and
32  * don't identify differences between PL2301 and PL2302, much less
33  * anything to explain the different PL2302 versions observed.
34  *
35  * NOTE:  pl2501 has several modes, including pl2301 and pl2302
36  * compatibility.   Some docs suggest the difference between 2301
37  * and 2302 is only to make MS-Windows use a different driver...
38  *
39  * pl25a1 glue based on patch from Tony Gibbs.  Prolific "docs" on
40  * this chip are as usual incomplete about what control messages
41  * are supported.
42  */
43 
44 /*
45  * Bits 0-4 can be used for software handshaking; they're set from
46  * one end, cleared from the other, "read" with the interrupt byte.
47  */
48 #define	PL_S_EN		(1<<7)		/* (feature only) suspend enable */
49 /* reserved bit -- rx ready (6) ? */
50 #define	PL_TX_READY	(1<<5)		/* (interrupt only) transmit ready */
51 #define	PL_RESET_OUT	(1<<4)		/* reset output pipe */
52 #define	PL_RESET_IN	(1<<3)		/* reset input pipe */
53 #define	PL_TX_C		(1<<2)		/* transmission complete */
54 #define	PL_TX_REQ	(1<<1)		/* transmission received */
55 #define	PL_PEER_E	(1<<0)		/* peer exists */
56 
57 static inline int
pl_vendor_req(struct usbnet * dev,u8 req,u8 val,u8 index)58 pl_vendor_req(struct usbnet *dev, u8 req, u8 val, u8 index)
59 {
60 	return usbnet_write_cmd(dev, req, USB_TYPE_VENDOR | USB_RECIP_DEVICE,
61 				val, index, NULL, 0);
62 }
63 
64 static inline int
pl_clear_QuickLink_features(struct usbnet * dev,int val)65 pl_clear_QuickLink_features(struct usbnet *dev, int val)
66 {
67 	return pl_vendor_req(dev, 1, (u8) val, 0);
68 }
69 
70 static inline int
pl_set_QuickLink_features(struct usbnet * dev,int val)71 pl_set_QuickLink_features(struct usbnet *dev, int val)
72 {
73 	return pl_vendor_req(dev, 3, (u8) val, 0);
74 }
75 
pl_reset(struct usbnet * dev)76 static int pl_reset(struct usbnet *dev)
77 {
78 	int status;
79 
80 	/* some units seem to need this reset, others reject it utterly.
81 	 * FIXME be more like "naplink" or windows drivers.
82 	 */
83 	status = pl_set_QuickLink_features(dev,
84 		PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);
85 	if (status != 0 && netif_msg_probe(dev))
86 		netif_dbg(dev, link, dev->net, "pl_reset --> %d\n", status);
87 	return 0;
88 }
89 
90 static const struct driver_info	prolific_info = {
91 	.description =	"Prolific PL-2301/PL-2302/PL-25A1/PL-27A1",
92 	.flags =	FLAG_POINTTOPOINT | FLAG_NO_SETINT,
93 		/* some PL-2302 versions seem to fail usb_set_interface() */
94 	.reset =	pl_reset,
95 };
96 
97 
98 /*-------------------------------------------------------------------------*/
99 
100 /*
101  * Proilific's name won't normally be on the cables, and
102  * may not be on the device.
103  */
104 
105 static const struct usb_device_id	products [] = {
106 
107 /* full speed cables */
108 {
109 	USB_DEVICE(0x067b, 0x0000),	// PL-2301
110 	.driver_info =	(unsigned long) &prolific_info,
111 }, {
112 	USB_DEVICE(0x067b, 0x0001),	// PL-2302
113 	.driver_info =	(unsigned long) &prolific_info,
114 },
115 
116 /* high speed cables */
117 {
118 	USB_DEVICE(0x067b, 0x25a1),     /* PL-25A1, no eeprom */
119 	.driver_info =  (unsigned long) &prolific_info,
120 }, {
121 	USB_DEVICE(0x050d, 0x258a),     /* Belkin F5U258/F5U279 (PL-25A1) */
122 	.driver_info =  (unsigned long) &prolific_info,
123 }, {
124 	USB_DEVICE(0x3923, 0x7825),     /* National Instruments USB
125 					 * Host-to-Host Cable
126 					 */
127 	.driver_info =  (unsigned long) &prolific_info,
128 
129 },
130 
131 /* super speed cables */
132 {
133 	USB_DEVICE(0x067b, 0x27a1),     /* PL-27A1, no eeprom
134 					 * also: goobay Active USB 3.0
135 					 * Data Link,
136 					 * Unitek Y-3501
137 					 */
138 	.driver_info =  (unsigned long) &prolific_info,
139 },
140 
141 	{ },		// END
142 };
143 MODULE_DEVICE_TABLE(usb, products);
144 
145 static struct usb_driver plusb_driver = {
146 	.name =		"plusb",
147 	.id_table =	products,
148 	.probe =	usbnet_probe,
149 	.disconnect =	usbnet_disconnect,
150 	.suspend =	usbnet_suspend,
151 	.resume =	usbnet_resume,
152 	.disable_hub_initiated_lpm = 1,
153 };
154 
155 module_usb_driver(plusb_driver);
156 
157 MODULE_AUTHOR("David Brownell");
158 MODULE_DESCRIPTION("Prolific PL-2301/2302/25A1/27A1 USB Host to Host Link Driver");
159 MODULE_LICENSE("GPL");
160