1 /*
2 * Wireless Host Controller (WHC) asynchronous schedule management.
3 *
4 * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License version
8 * 2 as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18 #include <linux/kernel.h>
19 #include <linux/dma-mapping.h>
20 #include <linux/uwb/umc.h>
21 #include <linux/usb.h>
22
23 #include "../../wusbcore/wusbhc.h"
24
25 #include "whcd.h"
26
qset_get_next_prev(struct whc * whc,struct whc_qset * qset,struct whc_qset ** next,struct whc_qset ** prev)27 static void qset_get_next_prev(struct whc *whc, struct whc_qset *qset,
28 struct whc_qset **next, struct whc_qset **prev)
29 {
30 struct list_head *n, *p;
31
32 BUG_ON(list_empty(&whc->async_list));
33
34 n = qset->list_node.next;
35 if (n == &whc->async_list)
36 n = n->next;
37 p = qset->list_node.prev;
38 if (p == &whc->async_list)
39 p = p->prev;
40
41 *next = container_of(n, struct whc_qset, list_node);
42 *prev = container_of(p, struct whc_qset, list_node);
43
44 }
45
asl_qset_insert_begin(struct whc * whc,struct whc_qset * qset)46 static void asl_qset_insert_begin(struct whc *whc, struct whc_qset *qset)
47 {
48 list_move(&qset->list_node, &whc->async_list);
49 qset->in_sw_list = true;
50 }
51
asl_qset_insert(struct whc * whc,struct whc_qset * qset)52 static void asl_qset_insert(struct whc *whc, struct whc_qset *qset)
53 {
54 struct whc_qset *next, *prev;
55
56 qset_clear(whc, qset);
57
58 /* Link into ASL. */
59 qset_get_next_prev(whc, qset, &next, &prev);
60 whc_qset_set_link_ptr(&qset->qh.link, next->qset_dma);
61 whc_qset_set_link_ptr(&prev->qh.link, qset->qset_dma);
62 qset->in_hw_list = true;
63 }
64
asl_qset_remove(struct whc * whc,struct whc_qset * qset)65 static void asl_qset_remove(struct whc *whc, struct whc_qset *qset)
66 {
67 struct whc_qset *prev, *next;
68
69 qset_get_next_prev(whc, qset, &next, &prev);
70
71 list_move(&qset->list_node, &whc->async_removed_list);
72 qset->in_sw_list = false;
73
74 /*
75 * No more qsets in the ASL? The caller must stop the ASL as
76 * it's no longer valid.
77 */
78 if (list_empty(&whc->async_list))
79 return;
80
81 /* Remove from ASL. */
82 whc_qset_set_link_ptr(&prev->qh.link, next->qset_dma);
83 qset->in_hw_list = false;
84 }
85
86 /**
87 * process_qset - process any recently inactivated or halted qTDs in a
88 * qset.
89 *
90 * After inactive qTDs are removed, new qTDs can be added if the
91 * urb queue still contains URBs.
92 *
93 * Returns any additional WUSBCMD bits for the ASL sync command (i.e.,
94 * WUSBCMD_ASYNC_QSET_RM if a halted qset was removed).
95 */
process_qset(struct whc * whc,struct whc_qset * qset)96 static uint32_t process_qset(struct whc *whc, struct whc_qset *qset)
97 {
98 enum whc_update update = 0;
99 uint32_t status = 0;
100
101 while (qset->ntds) {
102 struct whc_qtd *td;
103 int t;
104
105 t = qset->td_start;
106 td = &qset->qtd[qset->td_start];
107 status = le32_to_cpu(td->status);
108
109 /*
110 * Nothing to do with a still active qTD.
111 */
112 if (status & QTD_STS_ACTIVE)
113 break;
114
115 if (status & QTD_STS_HALTED) {
116 /* Ug, an error. */
117 process_halted_qtd(whc, qset, td);
118 goto done;
119 }
120
121 /* Mmm, a completed qTD. */
122 process_inactive_qtd(whc, qset, td);
123 }
124
125 update |= qset_add_qtds(whc, qset);
126
127 done:
128 /*
129 * Remove this qset from the ASL if requested, but only if has
130 * no qTDs.
131 */
132 if (qset->remove && qset->ntds == 0) {
133 asl_qset_remove(whc, qset);
134 update |= WHC_UPDATE_REMOVED;
135 }
136 return update;
137 }
138
asl_start(struct whc * whc)139 void asl_start(struct whc *whc)
140 {
141 struct whc_qset *qset;
142
143 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
144
145 le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);
146
147 whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
148 whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
149 WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
150 1000, "start ASL");
151 }
152
asl_stop(struct whc * whc)153 void asl_stop(struct whc *whc)
154 {
155 whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
156 whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
157 WUSBSTS_ASYNC_SCHED, 0,
158 1000, "stop ASL");
159 }
160
161 /**
162 * asl_update - request an ASL update and wait for the hardware to be synced
163 * @whc: the WHCI HC
164 * @wusbcmd: WUSBCMD value to start the update.
165 *
166 * If the WUSB HC is inactive (i.e., the ASL is stopped) then the
167 * update must be skipped as the hardware may not respond to update
168 * requests.
169 */
asl_update(struct whc * whc,uint32_t wusbcmd)170 void asl_update(struct whc *whc, uint32_t wusbcmd)
171 {
172 struct wusbhc *wusbhc = &whc->wusbhc;
173 long t;
174
175 mutex_lock(&wusbhc->mutex);
176 if (wusbhc->active) {
177 whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
178 t = wait_event_timeout(
179 whc->async_list_wq,
180 (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0,
181 msecs_to_jiffies(1000));
182 if (t == 0)
183 whc_hw_error(whc, "ASL update timeout");
184 }
185 mutex_unlock(&wusbhc->mutex);
186 }
187
188 /**
189 * scan_async_work - scan the ASL for qsets to process.
190 *
191 * Process each qset in the ASL in turn and then signal the WHC that
192 * the ASL has been updated.
193 *
194 * Then start, stop or update the asynchronous schedule as required.
195 */
scan_async_work(struct work_struct * work)196 void scan_async_work(struct work_struct *work)
197 {
198 struct whc *whc = container_of(work, struct whc, async_work);
199 struct whc_qset *qset, *t;
200 enum whc_update update = 0;
201
202 spin_lock_irq(&whc->lock);
203
204 /*
205 * Transerve the software list backwards so new qsets can be
206 * safely inserted into the ASL without making it non-circular.
207 */
208 list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
209 if (!qset->in_hw_list) {
210 asl_qset_insert(whc, qset);
211 update |= WHC_UPDATE_ADDED;
212 }
213
214 update |= process_qset(whc, qset);
215 }
216
217 spin_unlock_irq(&whc->lock);
218
219 if (update) {
220 uint32_t wusbcmd = WUSBCMD_ASYNC_UPDATED | WUSBCMD_ASYNC_SYNCED_DB;
221 if (update & WHC_UPDATE_REMOVED)
222 wusbcmd |= WUSBCMD_ASYNC_QSET_RM;
223 asl_update(whc, wusbcmd);
224 }
225
226 /*
227 * Now that the ASL is updated, complete the removal of any
228 * removed qsets.
229 */
230 spin_lock_irq(&whc->lock);
231
232 list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
233 qset_remove_complete(whc, qset);
234 }
235
236 spin_unlock_irq(&whc->lock);
237 }
238
239 /**
240 * asl_urb_enqueue - queue an URB onto the asynchronous list (ASL).
241 * @whc: the WHCI host controller
242 * @urb: the URB to enqueue
243 * @mem_flags: flags for any memory allocations
244 *
245 * The qset for the endpoint is obtained and the urb queued on to it.
246 *
247 * Work is scheduled to update the hardware's view of the ASL.
248 */
asl_urb_enqueue(struct whc * whc,struct urb * urb,gfp_t mem_flags)249 int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
250 {
251 struct whc_qset *qset;
252 int err;
253 unsigned long flags;
254
255 spin_lock_irqsave(&whc->lock, flags);
256
257 qset = get_qset(whc, urb, GFP_ATOMIC);
258 if (qset == NULL)
259 err = -ENOMEM;
260 else
261 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
262 if (!err) {
263 usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
264 if (!qset->in_sw_list)
265 asl_qset_insert_begin(whc, qset);
266 }
267
268 spin_unlock_irqrestore(&whc->lock, flags);
269
270 if (!err)
271 queue_work(whc->workqueue, &whc->async_work);
272
273 return 0;
274 }
275
276 /**
277 * asl_urb_dequeue - remove an URB (qset) from the async list.
278 * @whc: the WHCI host controller
279 * @urb: the URB to dequeue
280 * @status: the current status of the URB
281 *
282 * URBs that do yet have qTDs can simply be removed from the software
283 * queue, otherwise the qset must be removed from the ASL so the qTDs
284 * can be removed.
285 */
asl_urb_dequeue(struct whc * whc,struct urb * urb,int status)286 int asl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
287 {
288 struct whc_urb *wurb = urb->hcpriv;
289 struct whc_qset *qset = wurb->qset;
290 struct whc_std *std, *t;
291 int ret;
292 unsigned long flags;
293
294 spin_lock_irqsave(&whc->lock, flags);
295
296 ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
297 if (ret < 0)
298 goto out;
299
300 list_for_each_entry_safe(std, t, &qset->stds, list_node) {
301 if (std->urb == urb)
302 qset_free_std(whc, std);
303 else
304 std->qtd = NULL; /* so this std is re-added when the qset is */
305 }
306
307 asl_qset_remove(whc, qset);
308 wurb->status = status;
309 wurb->is_async = true;
310 queue_work(whc->workqueue, &wurb->dequeue_work);
311
312 out:
313 spin_unlock_irqrestore(&whc->lock, flags);
314
315 return ret;
316 }
317
318 /**
319 * asl_qset_delete - delete a qset from the ASL
320 */
asl_qset_delete(struct whc * whc,struct whc_qset * qset)321 void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
322 {
323 qset->remove = 1;
324 queue_work(whc->workqueue, &whc->async_work);
325 qset_delete(whc, qset);
326 }
327
328 /**
329 * asl_init - initialize the asynchronous schedule list
330 *
331 * A dummy qset with no qTDs is added to the ASL to simplify removing
332 * qsets (no need to stop the ASL when the last qset is removed).
333 */
asl_init(struct whc * whc)334 int asl_init(struct whc *whc)
335 {
336 struct whc_qset *qset;
337
338 qset = qset_alloc(whc, GFP_KERNEL);
339 if (qset == NULL)
340 return -ENOMEM;
341
342 asl_qset_insert_begin(whc, qset);
343 asl_qset_insert(whc, qset);
344
345 return 0;
346 }
347
348 /**
349 * asl_clean_up - free ASL resources
350 *
351 * The ASL is stopped and empty except for the dummy qset.
352 */
asl_clean_up(struct whc * whc)353 void asl_clean_up(struct whc *whc)
354 {
355 struct whc_qset *qset;
356
357 if (!list_empty(&whc->async_list)) {
358 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
359 list_del(&qset->list_node);
360 qset_free(whc, qset);
361 }
362 }
363