Merge branch 'for-linus2' of git://git.profusion.mobi/users/lucas/linux-2.6
[linux-2.6.git] / drivers / net / usb / cdc_eem.c
1 /*
2  * USB CDC EEM network interface driver
3  * Copyright (C) 2009 Oberthur Technologies
4  * by Omar Laazimani, Olivier Condemine
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License as published by
8  * the Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
19  */
20
21 #include <linux/module.h>
22 #include <linux/init.h>
23 #include <linux/netdevice.h>
24 #include <linux/etherdevice.h>
25 #include <linux/ctype.h>
26 #include <linux/ethtool.h>
27 #include <linux/workqueue.h>
28 #include <linux/mii.h>
29 #include <linux/usb.h>
30 #include <linux/crc32.h>
31 #include <linux/usb/cdc.h>
32 #include <linux/usb/usbnet.h>
33 #include <linux/gfp.h>
34
35
36 /*
37  * This driver is an implementation of the CDC "Ethernet Emulation
38  * Model" (EEM) specification, which encapsulates Ethernet frames
39  * for transport over USB using a simpler USB device model than the
40  * previous CDC "Ethernet Control Model" (ECM, or "CDC Ethernet").
41  *
42  * For details, see www.usb.org/developers/devclass_docs/CDC_EEM10.pdf
43  *
44  * This version has been tested with GIGAntIC WuaoW SIM Smart Card on 2.6.24,
45  * 2.6.27 and 2.6.30rc2 kernel.
46  * It has also been validated on Openmoko Om 2008.12 (based on 2.6.24 kernel).
47  * build on 23-April-2009
48  */
49
50 #define EEM_HEAD        2               /* 2 byte header */
51
52 /*-------------------------------------------------------------------------*/
53
54 static void eem_linkcmd_complete(struct urb *urb)
55 {
56         dev_kfree_skb(urb->context);
57         usb_free_urb(urb);
58 }
59
60 static void eem_linkcmd(struct usbnet *dev, struct sk_buff *skb)
61 {
62         struct urb              *urb;
63         int                     status;
64
65         urb = usb_alloc_urb(0, GFP_ATOMIC);
66         if (!urb)
67                 goto fail;
68
69         usb_fill_bulk_urb(urb, dev->udev, dev->out,
70                         skb->data, skb->len, eem_linkcmd_complete, skb);
71
72         status = usb_submit_urb(urb, GFP_ATOMIC);
73         if (status) {
74                 usb_free_urb(urb);
75 fail:
76                 dev_kfree_skb(skb);
77                 netdev_warn(dev->net, "link cmd failure\n");
78                 return;
79         }
80 }
81
82 static int eem_bind(struct usbnet *dev, struct usb_interface *intf)
83 {
84         int status = 0;
85
86         status = usbnet_get_endpoints(dev, intf);
87         if (status < 0) {
88                 usb_set_intfdata(intf, NULL);
89                 usb_driver_release_interface(driver_of(intf), intf);
90                 return status;
91         }
92
93         /* no jumbogram (16K) support for now */
94
95         dev->net->hard_header_len += EEM_HEAD + ETH_FCS_LEN;
96
97         return 0;
98 }
99
100 /*
101  * EEM permits packing multiple Ethernet frames into USB transfers
102  * (a "bundle"), but for TX we don't try to do that.
103  */
104 static struct sk_buff *eem_tx_fixup(struct usbnet *dev, struct sk_buff *skb,
105                                        gfp_t flags)
106 {
107         struct sk_buff  *skb2 = NULL;
108         u16             len = skb->len;
109         u32             crc = 0;
110         int             padlen = 0;
111
112         /* When ((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket) is
113          * zero, stick two bytes of zero length EEM packet on the end.
114          * Else the framework would add invalid single byte padding,
115          * since it can't know whether ZLPs will be handled right by
116          * all the relevant hardware and software.
117          */
118         if (!((len + EEM_HEAD + ETH_FCS_LEN) % dev->maxpacket))
119                 padlen += 2;
120
121         if (!skb_cloned(skb)) {
122                 int     headroom = skb_headroom(skb);
123                 int     tailroom = skb_tailroom(skb);
124
125                 if ((tailroom >= ETH_FCS_LEN + padlen) &&
126                     (headroom >= EEM_HEAD))
127                         goto done;
128
129                 if ((headroom + tailroom)
130                                 > (EEM_HEAD + ETH_FCS_LEN + padlen)) {
131                         skb->data = memmove(skb->head +
132                                         EEM_HEAD,
133                                         skb->data,
134                                         skb->len);
135                         skb_set_tail_pointer(skb, len);
136                         goto done;
137                 }
138         }
139
140         skb2 = skb_copy_expand(skb, EEM_HEAD, ETH_FCS_LEN + padlen, flags);
141         if (!skb2)
142                 return NULL;
143
144         dev_kfree_skb_any(skb);
145         skb = skb2;
146
147 done:
148         /* we don't use the "no Ethernet CRC" option */
149         crc = crc32_le(~0, skb->data, skb->len);
150         crc = ~crc;
151
152         put_unaligned_le32(crc, skb_put(skb, 4));
153
154         /* EEM packet header format:
155          * b0..13:      length of ethernet frame
156          * b14:         bmCRC (1 == valid Ethernet CRC)
157          * b15:         bmType (0 == data)
158          */
159         len = skb->len;
160         put_unaligned_le16(BIT(14) | len, skb_push(skb, 2));
161
162         /* Bundle a zero length EEM packet if needed */
163         if (padlen)
164                 put_unaligned_le16(0, skb_put(skb, 2));
165
166         return skb;
167 }
168
169 static int eem_rx_fixup(struct usbnet *dev, struct sk_buff *skb)
170 {
171         /*
172          * Our task here is to strip off framing, leaving skb with one
173          * data frame for the usbnet framework code to process.  But we
174          * may have received multiple EEM payloads, or command payloads.
175          * So we must process _everything_ as if it's a header, except
176          * maybe the last data payload
177          *
178          * REVISIT the framework needs updating so that when we consume
179          * all payloads (the last or only message was a command, or a
180          * zero length EEM packet) that is not accounted as an rx_error.
181          */
182         do {
183                 struct sk_buff  *skb2 = NULL;
184                 u16             header;
185                 u16             len = 0;
186
187                 /* incomplete EEM header? */
188                 if (skb->len < EEM_HEAD)
189                         return 0;
190
191                 /*
192                  * EEM packet header format:
193                  * b0..14:      EEM type dependent (Data or Command)
194                  * b15:         bmType
195                  */
196                 header = get_unaligned_le16(skb->data);
197                 skb_pull(skb, EEM_HEAD);
198
199                 /*
200                  * The bmType bit helps to denote when EEM
201                  * packet is data or command :
202                  *      bmType = 0      : EEM data payload
203                  *      bmType = 1      : EEM (link) command
204                  */
205                 if (header & BIT(15)) {
206                         u16     bmEEMCmd;
207
208                         /*
209                          * EEM (link) command packet:
210                          * b0..10:      bmEEMCmdParam
211                          * b11..13:     bmEEMCmd
212                          * b14:         bmReserved (must be 0)
213                          * b15:         1 (EEM command)
214                          */
215                         if (header & BIT(14)) {
216                                 netdev_dbg(dev->net, "reserved command %04x\n",
217                                            header);
218                                 continue;
219                         }
220
221                         bmEEMCmd = (header >> 11) & 0x7;
222                         switch (bmEEMCmd) {
223
224                         /* Responding to echo requests is mandatory. */
225                         case 0:         /* Echo command */
226                                 len = header & 0x7FF;
227
228                                 /* bogus command? */
229                                 if (skb->len < len)
230                                         return 0;
231
232                                 skb2 = skb_clone(skb, GFP_ATOMIC);
233                                 if (unlikely(!skb2))
234                                         goto next;
235                                 skb_trim(skb2, len);
236                                 put_unaligned_le16(BIT(15) | (1 << 11) | len,
237                                                 skb_push(skb2, 2));
238                                 eem_linkcmd(dev, skb2);
239                                 break;
240
241                         /*
242                          * Host may choose to ignore hints.
243                          *  - suspend: peripheral ready to suspend
244                          *  - response: suggest N millisec polling
245                          *  - response complete: suggest N sec polling
246                          */
247                         case 2:         /* Suspend hint */
248                         case 3:         /* Response hint */
249                         case 4:         /* Response complete hint */
250                                 continue;
251
252                         /*
253                          * Hosts should never receive host-to-peripheral
254                          * or reserved command codes; or responses to an
255                          * echo command we didn't send.
256                          */
257                         case 1:         /* Echo response */
258                         case 5:         /* Tickle */
259                         default:        /* reserved */
260                                 netdev_warn(dev->net,
261                                             "unexpected link command %d\n",
262                                             bmEEMCmd);
263                                 continue;
264                         }
265
266                 } else {
267                         u32     crc, crc2;
268                         int     is_last;
269
270                         /* zero length EEM packet? */
271                         if (header == 0)
272                                 continue;
273
274                         /*
275                          * EEM data packet header :
276                          * b0..13:      length of ethernet frame
277                          * b14:         bmCRC
278                          * b15:         0 (EEM data)
279                          */
280                         len = header & 0x3FFF;
281
282                         /* bogus EEM payload? */
283                         if (skb->len < len)
284                                 return 0;
285
286                         /* bogus ethernet frame? */
287                         if (len < (ETH_HLEN + ETH_FCS_LEN))
288                                 goto next;
289
290                         /*
291                          * Treat the last payload differently: framework
292                          * code expects our "fixup" to have stripped off
293                          * headers, so "skb" is a data packet (or error).
294                          * Else if it's not the last payload, keep "skb"
295                          * for further processing.
296                          */
297                         is_last = (len == skb->len);
298                         if (is_last)
299                                 skb2 = skb;
300                         else {
301                                 skb2 = skb_clone(skb, GFP_ATOMIC);
302                                 if (unlikely(!skb2))
303                                         return 0;
304                         }
305
306                         /*
307                          * The bmCRC helps to denote when the CRC field in
308                          * the Ethernet frame contains a calculated CRC:
309                          *      bmCRC = 1       : CRC is calculated
310                          *      bmCRC = 0       : CRC = 0xDEADBEEF
311                          */
312                         if (header & BIT(14)) {
313                                 crc = get_unaligned_le32(skb2->data
314                                                 + len - ETH_FCS_LEN);
315                                 crc2 = ~crc32_le(~0, skb2->data, skb2->len
316                                                 - ETH_FCS_LEN);
317                         } else {
318                                 crc = get_unaligned_be32(skb2->data
319                                                 + len - ETH_FCS_LEN);
320                                 crc2 = 0xdeadbeef;
321                         }
322                         skb_trim(skb2, len - ETH_FCS_LEN);
323
324                         if (is_last)
325                                 return crc == crc2;
326
327                         if (unlikely(crc != crc2)) {
328                                 dev->net->stats.rx_errors++;
329                                 dev_kfree_skb_any(skb2);
330                         } else
331                                 usbnet_skb_return(dev, skb2);
332                 }
333
334 next:
335                 skb_pull(skb, len);
336         } while (skb->len);
337
338         return 1;
339 }
340
341 static const struct driver_info eem_info = {
342         .description =  "CDC EEM Device",
343         .flags =        FLAG_ETHER | FLAG_POINTTOPOINT,
344         .bind =         eem_bind,
345         .rx_fixup =     eem_rx_fixup,
346         .tx_fixup =     eem_tx_fixup,
347 };
348
349 /*-------------------------------------------------------------------------*/
350
351 static const struct usb_device_id products[] = {
352 {
353         USB_INTERFACE_INFO(USB_CLASS_COMM, USB_CDC_SUBCLASS_EEM,
354                         USB_CDC_PROTO_EEM),
355         .driver_info = (unsigned long) &eem_info,
356 },
357 {
358         /* EMPTY == end of list */
359 },
360 };
361 MODULE_DEVICE_TABLE(usb, products);
362
363 static struct usb_driver eem_driver = {
364         .name =         "cdc_eem",
365         .id_table =     products,
366         .probe =        usbnet_probe,
367         .disconnect =   usbnet_disconnect,
368         .suspend =      usbnet_suspend,
369         .resume =       usbnet_resume,
370 };
371
372
373 static int __init eem_init(void)
374 {
375         return usb_register(&eem_driver);
376 }
377 module_init(eem_init);
378
379 static void __exit eem_exit(void)
380 {
381         usb_deregister(&eem_driver);
382 }
383 module_exit(eem_exit);
384
385 MODULE_AUTHOR("Omar Laazimani <omar.oberthur@gmail.com>");
386 MODULE_DESCRIPTION("USB CDC EEM");
387 MODULE_LICENSE("GPL");