drivers/net/usb/plusb.c

   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
  58 pl_vendor_req(struct usbnet *dev, u8 req, u8 val, u8 index)
  59 {
  60         return usbnet_read_cmd(dev, req,
  61                                 USB_DIR_IN | USB_TYPE_VENDOR |
  62                                 USB_RECIP_DEVICE,
  63                                 val, index, NULL, 0);
  64 }
  65
  66 static inline int
  67 pl_clear_QuickLink_features(struct usbnet *dev, int val)
  68 {
  69         return pl_vendor_req(dev, 1, (u8) val, 0);
  70 }
  71
  72 static inline int
  73 pl_set_QuickLink_features(struct usbnet *dev, int val)
  74 {
  75         return pl_vendor_req(dev, 3, (u8) val, 0);
  76 }
  77
  78 static int pl_reset(struct usbnet *dev)
  79 {
  80         int status;
  81
  82         /* some units seem to need this reset, others reject it utterly.
  83          * FIXME be more like "naplink" or windows drivers.
  84          */
  85         status = pl_set_QuickLink_features(dev,
  86                 PL_S_EN|PL_RESET_OUT|PL_RESET_IN|PL_PEER_E);
  87         if (status != 0 && netif_msg_probe(dev))
  88                 netif_dbg(dev, link, dev->net, "pl_reset --> %d\n", status);
  89         return 0;
  90 }
  91
  92 static const struct driver_info prolific_info = {
  93         .description =  "Prolific PL-2301/PL-2302/PL-25A1/PL-27A1",
  94         .flags =        FLAG_POINTTOPOINT | FLAG_NO_SETINT,
  95                 /* some PL-2302 versions seem to fail usb_set_interface() */
  96         .reset =        pl_reset,
  97 };
  98
  99
 100 /*-------------------------------------------------------------------------*/
 101
 102 /*
 103  * Proilific's name won't normally be on the cables, and
 104  * may not be on the device.
 105  */
 106
 107 static const struct usb_device_id       products [] = {
 108
 109 /* full speed cables */
 110 {
 111         USB_DEVICE(0x067b, 0x0000),     // PL-2301
 112         .driver_info =  (unsigned long) &prolific_info,
 113 }, {
 114         USB_DEVICE(0x067b, 0x0001),     // PL-2302
 115         .driver_info =  (unsigned long) &prolific_info,
 116 },
 117
 118 /* high speed cables */
 119 {
 120         USB_DEVICE(0x067b, 0x25a1),     /* PL-25A1, no eeprom */
 121         .driver_info =  (unsigned long) &prolific_info,
 122 }, {
 123         USB_DEVICE(0x050d, 0x258a),     /* Belkin F5U258/F5U279 (PL-25A1) */
 124         .driver_info =  (unsigned long) &prolific_info,
 125 }, {
 126         USB_DEVICE(0x3923, 0x7825),     /* National Instruments USB
 127                                          * Host-to-Host Cable
 128                                          */
 129         .driver_info =  (unsigned long) &prolific_info,
 130
 131 },
 132
 133 /* super speed cables */
 134 {
 135         USB_DEVICE(0x067b, 0x27a1),     /* PL-27A1, no eeprom
 136                                          * also: goobay Active USB 3.0
 137                                          * Data Link,
 138                                          * Unitek Y-3501
 139                                          */
 140         .driver_info =  (unsigned long) &prolific_info,
 141 },
 142
 143         { },            // END
 144 };
 145 MODULE_DEVICE_TABLE(usb, products);
 146
 147 static struct usb_driver plusb_driver = {
 148         .name =         "plusb",
 149         .id_table =     products,
 150         .probe =        usbnet_probe,
 151         .disconnect =   usbnet_disconnect,
 152         .suspend =      usbnet_suspend,
 153         .resume =       usbnet_resume,
 154         .disable_hub_initiated_lpm = 1,
 155 };
 156
 157 module_usb_driver(plusb_driver);
 158
 159 MODULE_AUTHOR("David Brownell");
 160 MODULE_DESCRIPTION("Prolific PL-2301/2302/25A1/27A1 USB Host to Host Link Driver");
 161 MODULE_LICENSE("GPL");