xref: /openbmc/linux/drivers/net/usb/cdc_subset.c (revision aac28965)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Simple "CDC Subset" USB Networking Links
4  * Copyright (C) 2000-2005 by David Brownell
5  */
6 
7 #include <linux/module.h>
8 #include <linux/kmod.h>
9 #include <linux/netdevice.h>
10 #include <linux/etherdevice.h>
11 #include <linux/ethtool.h>
12 #include <linux/workqueue.h>
13 #include <linux/mii.h>
14 #include <linux/usb.h>
15 #include <linux/usb/usbnet.h>
16 
17 
18 /*
19  * This supports simple USB network links that don't require any special
20  * framing or hardware control operations.  The protocol used here is a
21  * strict subset of CDC Ethernet, with three basic differences reflecting
22  * the goal that almost any hardware should run it:
23  *
24  *  - Minimal runtime control:  one interface, no altsettings, and
25  *    no vendor or class specific control requests.  If a device is
26  *    configured, it is allowed to exchange packets with the host.
27  *    Fancier models would mean not working on some hardware.
28  *
29  *  - Minimal manufacturing control:  no IEEE "Organizationally
30  *    Unique ID" required, or an EEPROMs to store one.  Each host uses
31  *    one random "locally assigned" Ethernet address instead, which can
32  *    of course be overridden using standard tools like "ifconfig".
33  *    (With 2^46 such addresses, same-net collisions are quite rare.)
34  *
35  *  - There is no additional framing data for USB.  Packets are written
36  *    exactly as in CDC Ethernet, starting with an Ethernet header and
37  *    terminated by a short packet.  However, the host will never send a
38  *    zero length packet; some systems can't handle those robustly.
39  *
40  * Anything that can transmit and receive USB bulk packets can implement
41  * this protocol.  That includes both smart peripherals and quite a lot
42  * of "host-to-host" USB cables (which embed two devices back-to-back).
43  *
44  * Note that although Linux may use many of those host-to-host links
45  * with this "cdc_subset" framing, that doesn't mean there may not be a
46  * better approach.  Handling the "other end unplugs/replugs" scenario
47  * well tends to require chip-specific vendor requests.  Also, Windows
48  * peers at the other end of host-to-host cables may expect their own
49  * framing to be used rather than this "cdc_subset" model.
50  */
51 
52 #if defined(CONFIG_USB_EPSON2888) || defined(CONFIG_USB_ARMLINUX)
53 /* PDA style devices are always connected if present */
54 static int always_connected (struct usbnet *dev)
55 {
56 	return 0;
57 }
58 #endif
59 
60 #ifdef	CONFIG_USB_ALI_M5632
61 #define	HAVE_HARDWARE
62 
63 /*-------------------------------------------------------------------------
64  *
65  * ALi M5632 driver ... does high speed
66  *
67  * NOTE that the MS-Windows drivers for this chip use some funky and
68  * (naturally) undocumented 7-byte prefix to each packet, so this is a
69  * case where we don't currently interoperate.  Also, once you unplug
70  * one end of the cable, you need to replug the other end too ... since
71  * chip docs are unavailable, there's no way to reset the relevant state
72  * short of a power cycle.
73  *
74  *-------------------------------------------------------------------------*/
75 
76 static void m5632_recover(struct usbnet *dev)
77 {
78 	struct usb_device	*udev = dev->udev;
79 	struct usb_interface	*intf = dev->intf;
80 	int r;
81 
82 	r = usb_lock_device_for_reset(udev, intf);
83 	if (r < 0)
84 		return;
85 
86 	usb_reset_device(udev);
87 	usb_unlock_device(udev);
88 }
89 
90 static const struct driver_info	ali_m5632_info = {
91 	.description =	"ALi M5632",
92 	.flags       = FLAG_POINTTOPOINT,
93 	.recover     = m5632_recover,
94 };
95 
96 #endif
97 
98 #ifdef	CONFIG_USB_AN2720
99 #define	HAVE_HARDWARE
100 
101 /*-------------------------------------------------------------------------
102  *
103  * AnchorChips 2720 driver ... http://www.cypress.com
104  *
105  * This doesn't seem to have a way to detect whether the peer is
106  * connected, or need any reset handshaking.  It's got pretty big
107  * internal buffers (handles most of a frame's worth of data).
108  * Chip data sheets don't describe any vendor control messages.
109  *
110  *-------------------------------------------------------------------------*/
111 
112 static const struct driver_info	an2720_info = {
113 	.description =	"AnchorChips/Cypress 2720",
114 	.flags       = FLAG_POINTTOPOINT,
115 	// no reset available!
116 	// no check_connect available!
117 
118 	.in = 2, .out = 2,		// direction distinguishes these
119 };
120 
121 #endif	/* CONFIG_USB_AN2720 */
122 
123 
124 #ifdef	CONFIG_USB_BELKIN
125 #define	HAVE_HARDWARE
126 
127 /*-------------------------------------------------------------------------
128  *
129  * Belkin F5U104 ... two NetChip 2280 devices + Atmel AVR microcontroller
130  *
131  * ... also two eTEK designs, including one sold as "Advance USBNET"
132  *
133  *-------------------------------------------------------------------------*/
134 
135 static const struct driver_info	belkin_info = {
136 	.description =	"Belkin, eTEK, or compatible",
137 	.flags       = FLAG_POINTTOPOINT,
138 };
139 
140 #endif	/* CONFIG_USB_BELKIN */
141 
142 
143 
144 #ifdef	CONFIG_USB_EPSON2888
145 #define	HAVE_HARDWARE
146 
147 /*-------------------------------------------------------------------------
148  *
149  * EPSON USB clients
150  *
151  * This is the same idea as Linux PDAs (below) except the firmware in the
152  * device might not be Tux-powered.  Epson provides reference firmware that
153  * implements this interface.  Product developers can reuse or modify that
154  * code, such as by using their own product and vendor codes.
155  *
156  * Support was from Juro Bystricky <bystricky.juro@erd.epson.com>
157  *
158  *-------------------------------------------------------------------------*/
159 
160 static const struct driver_info	epson2888_info = {
161 	.description =	"Epson USB Device",
162 	.check_connect = always_connected,
163 	.flags = FLAG_POINTTOPOINT,
164 
165 	.in = 4, .out = 3,
166 };
167 
168 #endif	/* CONFIG_USB_EPSON2888 */
169 
170 
171 /*-------------------------------------------------------------------------
172  *
173  * info from Jonathan McDowell <noodles@earth.li>
174  *
175  *-------------------------------------------------------------------------*/
176 #ifdef CONFIG_USB_KC2190
177 #define HAVE_HARDWARE
178 static const struct driver_info kc2190_info = {
179 	.description =  "KC Technology KC-190",
180 	.flags = FLAG_POINTTOPOINT,
181 };
182 #endif /* CONFIG_USB_KC2190 */
183 
184 
185 #ifdef	CONFIG_USB_ARMLINUX
186 #define	HAVE_HARDWARE
187 
188 /*-------------------------------------------------------------------------
189  *
190  * Intel's SA-1100 chip integrates basic USB support, and is used
191  * in PDAs like some iPaqs, the Yopy, some Zaurus models, and more.
192  * When they run Linux, arch/arm/mach-sa1100/usb-eth.c may be used to
193  * network using minimal USB framing data.
194  *
195  * This describes the driver currently in standard ARM Linux kernels.
196  * The Zaurus uses a different driver (see later).
197  *
198  * PXA25x and PXA210 use XScale cores (ARM v5TE) with better USB support
199  * and different USB endpoint numbering than the SA1100 devices.  The
200  * mach-pxa/usb-eth.c driver re-uses the device ids from mach-sa1100
201  * so we rely on the endpoint descriptors.
202  *
203  *-------------------------------------------------------------------------*/
204 
205 static const struct driver_info	linuxdev_info = {
206 	.description =	"Linux Device",
207 	.check_connect = always_connected,
208 	.flags = FLAG_POINTTOPOINT,
209 };
210 
211 static const struct driver_info	yopy_info = {
212 	.description =	"Yopy",
213 	.check_connect = always_connected,
214 	.flags = FLAG_POINTTOPOINT,
215 };
216 
217 static const struct driver_info	blob_info = {
218 	.description =	"Boot Loader OBject",
219 	.check_connect = always_connected,
220 	.flags = FLAG_POINTTOPOINT,
221 };
222 
223 #endif	/* CONFIG_USB_ARMLINUX */
224 
225 
226 /*-------------------------------------------------------------------------*/
227 
228 #ifndef	HAVE_HARDWARE
229 #warning You need to configure some hardware for this driver
230 #endif
231 
232 /*
233  * chip vendor names won't normally be on the cables, and
234  * may not be on the device.
235  */
236 
237 static const struct usb_device_id	products [] = {
238 
239 #ifdef	CONFIG_USB_ALI_M5632
240 {
241 	USB_DEVICE (0x0402, 0x5632),	// ALi defaults
242 	.driver_info =	(unsigned long) &ali_m5632_info,
243 },
244 {
245 	USB_DEVICE (0x182d,0x207c),	// SiteCom CN-124
246 	.driver_info =	(unsigned long) &ali_m5632_info,
247 },
248 #endif
249 
250 #ifdef	CONFIG_USB_AN2720
251 {
252 	USB_DEVICE (0x0547, 0x2720),	// AnchorChips defaults
253 	.driver_info =	(unsigned long) &an2720_info,
254 }, {
255 	USB_DEVICE (0x0547, 0x2727),	// Xircom PGUNET
256 	.driver_info =	(unsigned long) &an2720_info,
257 },
258 #endif
259 
260 #ifdef	CONFIG_USB_BELKIN
261 {
262 	USB_DEVICE (0x050d, 0x0004),	// Belkin
263 	.driver_info =	(unsigned long) &belkin_info,
264 }, {
265 	USB_DEVICE (0x056c, 0x8100),	// eTEK
266 	.driver_info =	(unsigned long) &belkin_info,
267 }, {
268 	USB_DEVICE (0x0525, 0x9901),	// Advance USBNET (eTEK)
269 	.driver_info =	(unsigned long) &belkin_info,
270 },
271 #endif
272 
273 #ifdef	CONFIG_USB_EPSON2888
274 {
275 	USB_DEVICE (0x0525, 0x2888),	// EPSON USB client
276 	.driver_info	= (unsigned long) &epson2888_info,
277 },
278 #endif
279 
280 #ifdef CONFIG_USB_KC2190
281 {
282 	USB_DEVICE (0x050f, 0x0190),	// KC-190
283 	.driver_info =	(unsigned long) &kc2190_info,
284 },
285 #endif
286 
287 #ifdef	CONFIG_USB_ARMLINUX
288 /*
289  * SA-1100 using standard ARM Linux kernels, or compatible.
290  * Often used when talking to Linux PDAs (iPaq, Yopy, etc).
291  * The sa-1100 "usb-eth" driver handles the basic framing.
292  *
293  * PXA25x or PXA210 ...  these use a "usb-eth" driver much like
294  * the sa1100 one, but hardware uses different endpoint numbers.
295  *
296  * Or the Linux "Ethernet" gadget on hardware that can't talk
297  * CDC Ethernet (e.g., no altsettings), in either of two modes:
298  *  - acting just like the old "usb-eth" firmware, though
299  *    the implementation is different
300  *  - supporting RNDIS as the first/default configuration for
301  *    MS-Windows interop; Linux needs to use the other config
302  */
303 {
304 	// 1183 = 0x049F, both used as hex values?
305 	// Compaq "Itsy" vendor/product id
306 	USB_DEVICE (0x049F, 0x505A),	// usb-eth, or compatible
307 	.driver_info =	(unsigned long) &linuxdev_info,
308 }, {
309 	USB_DEVICE (0x0E7E, 0x1001),	// G.Mate "Yopy"
310 	.driver_info =	(unsigned long) &yopy_info,
311 }, {
312 	USB_DEVICE (0x8086, 0x07d3),	// "blob" bootloader
313 	.driver_info =	(unsigned long) &blob_info,
314 }, {
315 	USB_DEVICE (0x1286, 0x8001),    // "blob" bootloader
316 	.driver_info =  (unsigned long) &blob_info,
317 }, {
318 	// Linux Ethernet/RNDIS gadget, mostly on PXA, second config
319 	// e.g. Gumstix, current OpenZaurus, ... or anything else
320 	// that just enables this gadget option.
321 	USB_DEVICE (0x0525, 0xa4a2),
322 	.driver_info =	(unsigned long) &linuxdev_info,
323 },
324 #endif
325 
326 	{ },		// END
327 };
328 MODULE_DEVICE_TABLE(usb, products);
329 
330 /*-------------------------------------------------------------------------*/
331 static int dummy_prereset(struct usb_interface *intf)
332 {
333         return 0;
334 }
335 
336 static int dummy_postreset(struct usb_interface *intf)
337 {
338         return 0;
339 }
340 
341 static struct usb_driver cdc_subset_driver = {
342 	.name =		"cdc_subset",
343 	.probe =	usbnet_probe,
344 	.suspend =	usbnet_suspend,
345 	.resume =	usbnet_resume,
346 	.pre_reset =	dummy_prereset,
347 	.post_reset =	dummy_postreset,
348 	.disconnect =	usbnet_disconnect,
349 	.id_table =	products,
350 	.disable_hub_initiated_lpm = 1,
351 };
352 
353 module_usb_driver(cdc_subset_driver);
354 
355 MODULE_AUTHOR("David Brownell");
356 MODULE_DESCRIPTION("Simple 'CDC Subset' USB networking links");
357 MODULE_LICENSE("GPL");
358