tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * WUSB Wire Adapter: Control/Data Streaming Interface (WUSB[8])
3 * Notification EndPoint support
4 *
5 * Copyright (C) 2006 Intel Corporation
6 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License version
10 * 2 as published by the Free Software Foundation.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
20 * 02110-1301, USA.
21 *
22 *
23 * This part takes care of getting the notification from the hw
24 * only and dispatching through wusbwad into
25 * wa_notif_dispatch. Handling is done there.
26 *
27 * WA notifications are limited in size; most of them are three or
28 * four bytes long, and the longest is the HWA Device Notification,
29 * which would not exceed 38 bytes (DNs are limited in payload to 32
30 * bytes plus 3 bytes header (WUSB1.0[7.6p2]), plus 3 bytes HWA
31 * header (WUSB1.0[8.5.4.2]).
32 *
33 * It is not clear if more than one Device Notification can be packed
34 * in a HWA Notification, I assume no because of the wording in
35 * WUSB1.0[8.5.4.2]. In any case, the bigger any notification could
36 * get is 256 bytes (as the bLength field is a byte).
37 *
38 * So what we do is we have this buffer and read into it; when a
39 * notification arrives we schedule work to a specific, single thread
40 * workqueue (so notifications are serialized) and copy the
41 * notification data. After scheduling the work, we rearm the read from
42 * the notification endpoint.
43 *
44 * Entry points here are:
45 *
46 * wa_nep_[create|destroy]() To initialize/release this subsystem
47 *
48 * wa_nep_cb() Callback for the notification
49 * endpoint; when data is ready, this
50 * does the dispatching.
51 */
52#include <linux/workqueue.h>
53#include <linux/ctype.h>
54#include <linux/slab.h>
55
56#include "wa-hc.h"
57#include "wusbhc.h"
58
59/* Structure for queueing notifications to the workqueue */
60struct wa_notif_work {
61 struct work_struct work;
62 struct wahc *wa;
63 size_t size;
64 u8 data[];
65};
66
67/*
68 * Process incoming notifications from the WA's Notification EndPoint
69 * [the wuswad daemon, basically]
70 *
71 * @_nw: Pointer to a descriptor which has the pointer to the
72 * @wa, the size of the buffer and the work queue
73 * structure (so we can free all when done).
74 * @returns 0 if ok, < 0 errno code on error.
75 *
76 * All notifications follow the same format; they need to start with a
77 * 'struct wa_notif_hdr' header, so it is easy to parse through
78 * them. We just break the buffer in individual notifications (the
79 * standard doesn't say if it can be done or is forbidden, so we are
80 * cautious) and dispatch each.
81 *
82 * So the handling layers are is:
83 *
84 * WA specific notification (from NEP)
85 * Device Notification Received -> wa_handle_notif_dn()
86 * WUSB Device notification generic handling
87 * BPST Adjustment -> wa_handle_notif_bpst_adj()
88 * ... -> ...
89 *
90 * @wa has to be referenced
91 */
92static void wa_notif_dispatch(struct work_struct *ws)
93{
94 void *itr;
95 u8 missing = 0;
96 struct wa_notif_work *nw = container_of(ws, struct wa_notif_work,
97 work);
98 struct wahc *wa = nw->wa;
99 struct wa_notif_hdr *notif_hdr;
100 size_t size;
101
102 struct device *dev = &wa->usb_iface->dev;
103
104#if 0
105 /* FIXME: need to check for this??? */
106 if (usb_hcd->state == HC_STATE_QUIESCING) /* Going down? */
107 goto out; /* screw it */
108#endif
109 atomic_dec(&wa->notifs_queued); /* Throttling ctl */
110 dev = &wa->usb_iface->dev;
111 size = nw->size;
112 itr = nw->data;
113
114 while (size) {
115 if (size < sizeof(*notif_hdr)) {
116 missing = sizeof(*notif_hdr) - size;
117 goto exhausted_buffer;
118 }
119 notif_hdr = itr;
120 if (size < notif_hdr->bLength)
121 goto exhausted_buffer;
122 itr += notif_hdr->bLength;
123 size -= notif_hdr->bLength;
124 /* Dispatch the notification [don't use itr or size!] */
125 switch (notif_hdr->bNotifyType) {
126 case HWA_NOTIF_DN: {
127 struct hwa_notif_dn *hwa_dn;
128 hwa_dn = container_of(notif_hdr, struct hwa_notif_dn,
129 hdr);
130 wusbhc_handle_dn(wa->wusb, hwa_dn->bSourceDeviceAddr,
131 hwa_dn->dndata,
132 notif_hdr->bLength - sizeof(*hwa_dn));
133 break;
134 }
135 case WA_NOTIF_TRANSFER:
136 wa_handle_notif_xfer(wa, notif_hdr);
137 break;
138 case HWA_NOTIF_BPST_ADJ:
139 break; /* no action needed for BPST ADJ. */
140 case DWA_NOTIF_RWAKE:
141 case DWA_NOTIF_PORTSTATUS:
142 /* FIXME: unimplemented WA NOTIFs */
143 /* fallthru */
144 default:
145 dev_err(dev, "HWA: unknown notification 0x%x, "
146 "%zu bytes; discarding\n",
147 notif_hdr->bNotifyType,
148 (size_t)notif_hdr->bLength);
149 break;
150 }
151 }
152out:
153 wa_put(wa);
154 kfree(nw);
155 return;
156
157 /* THIS SHOULD NOT HAPPEN
158 *
159 * Buffer exahusted with partial data remaining; just warn and
160 * discard the data, as this should not happen.
161 */
162exhausted_buffer:
163 dev_warn(dev, "HWA: device sent short notification, "
164 "%d bytes missing; discarding %d bytes.\n",
165 missing, (int)size);
166 goto out;
167}
168
169/*
170 * Deliver incoming WA notifications to the wusbwa workqueue
171 *
172 * @wa: Pointer the Wire Adapter Controller Data Streaming
173 * instance (part of an 'struct usb_hcd').
174 * @size: Size of the received buffer
175 * @returns 0 if ok, < 0 errno code on error.
176 *
177 * The input buffer is @wa->nep_buffer, with @size bytes
178 * (guaranteed to fit in the allocated space,
179 * @wa->nep_buffer_size).
180 */
181static int wa_nep_queue(struct wahc *wa, size_t size)
182{
183 int result = 0;
184 struct device *dev = &wa->usb_iface->dev;
185 struct wa_notif_work *nw;
186
187 /* dev_fnstart(dev, "(wa %p, size %zu)\n", wa, size); */
188 BUG_ON(size > wa->nep_buffer_size);
189 if (size == 0)
190 goto out;
191 if (atomic_read(&wa->notifs_queued) > 200) {
192 if (printk_ratelimit())
193 dev_err(dev, "Too many notifications queued, "
194 "throttling back\n");
195 goto out;
196 }
197 nw = kzalloc(sizeof(*nw) + size, GFP_ATOMIC);
198 if (nw == NULL) {
199 if (printk_ratelimit())
200 dev_err(dev, "No memory to queue notification\n");
201 result = -ENOMEM;
202 goto out;
203 }
204 INIT_WORK(&nw->work, wa_notif_dispatch);
205 nw->wa = wa_get(wa);
206 nw->size = size;
207 memcpy(nw->data, wa->nep_buffer, size);
208 atomic_inc(&wa->notifs_queued); /* Throttling ctl */
209 queue_work(wusbd, &nw->work);
210out:
211 /* dev_fnend(dev, "(wa %p, size %zu) = result\n", wa, size, result); */
212 return result;
213}
214
215/*
216 * Callback for the notification event endpoint
217 *
218 * Check's that everything is fine and then passes the data to be
219 * queued to the workqueue.
220 */
221static void wa_nep_cb(struct urb *urb)
222{
223 int result;
224 struct wahc *wa = urb->context;
225 struct device *dev = &wa->usb_iface->dev;
226
227 switch (result = urb->status) {
228 case 0:
229 result = wa_nep_queue(wa, urb->actual_length);
230 if (result < 0)
231 dev_err(dev, "NEP: unable to process notification(s): "
232 "%d\n", result);
233 break;
234 case -ECONNRESET: /* Not an error, but a controlled situation; */
235 case -ENOENT: /* (we killed the URB)...so, no broadcast */
236 case -ESHUTDOWN:
237 dev_dbg(dev, "NEP: going down %d\n", urb->status);
238 goto out;
239 default: /* On general errors, we retry unless it gets ugly */
240 if (edc_inc(&wa->nep_edc, EDC_MAX_ERRORS,
241 EDC_ERROR_TIMEFRAME)) {
242 dev_err(dev, "NEP: URB max acceptable errors "
243 "exceeded, resetting device\n");
244 wa_reset_all(wa);
245 goto out;
246 }
247 dev_err(dev, "NEP: URB error %d\n", urb->status);
248 }
249 result = wa_nep_arm(wa, GFP_ATOMIC);
250 if (result < 0) {
251 dev_err(dev, "NEP: cannot submit URB: %d\n", result);
252 wa_reset_all(wa);
253 }
254out:
255 return;
256}
257
258/*
259 * Initialize @wa's notification and event's endpoint stuff
260 *
261 * This includes the allocating the read buffer, the context ID
262 * allocation bitmap, the URB and submitting the URB.
263 */
264int wa_nep_create(struct wahc *wa, struct usb_interface *iface)
265{
266 int result;
267 struct usb_endpoint_descriptor *epd;
268 struct usb_device *usb_dev = interface_to_usbdev(iface);
269 struct device *dev = &iface->dev;
270
271 edc_init(&wa->nep_edc);
272 epd = &iface->cur_altsetting->endpoint[0].desc;
273 wa->nep_buffer_size = 1024;
274 wa->nep_buffer = kmalloc(wa->nep_buffer_size, GFP_KERNEL);
275 if (!wa->nep_buffer)
276 goto error_nep_buffer;
277 wa->nep_urb = usb_alloc_urb(0, GFP_KERNEL);
278 if (wa->nep_urb == NULL)
279 goto error_urb_alloc;
280 usb_fill_int_urb(wa->nep_urb, usb_dev,
281 usb_rcvintpipe(usb_dev, epd->bEndpointAddress),
282 wa->nep_buffer, wa->nep_buffer_size,
283 wa_nep_cb, wa, epd->bInterval);
284 result = wa_nep_arm(wa, GFP_KERNEL);
285 if (result < 0) {
286 dev_err(dev, "Cannot submit notification URB: %d\n", result);
287 goto error_nep_arm;
288 }
289 return 0;
290
291error_nep_arm:
292 usb_free_urb(wa->nep_urb);
293error_urb_alloc:
294 kfree(wa->nep_buffer);
295error_nep_buffer:
296 return -ENOMEM;
297}
298
299void wa_nep_destroy(struct wahc *wa)
300{
301 wa_nep_disarm(wa);
302 usb_free_urb(wa->nep_urb);
303 kfree(wa->nep_buffer);
304}