drivers/usb/host/whci/asl.c

   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
  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
  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
  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
  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  */
  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                         /* A halted qTD always triggers an update
 119                            because the qset was either removed or
 120                            reactivated. */
 121                         update |= WHC_UPDATE_UPDATED;
 122                         goto done;
 123                 }
 124
 125                 /* Mmm, a completed qTD. */
 126                 process_inactive_qtd(whc, qset, td);
 127         }
 128
 129         if (!qset->remove)
 130                 update |= qset_add_qtds(whc, qset);
 131
 132 done:
 133         /*
 134          * Remove this qset from the ASL if requested, but only if has
 135          * no qTDs.
 136          */
 137         if (qset->remove && qset->ntds == 0) {
 138                 asl_qset_remove(whc, qset);
 139                 update |= WHC_UPDATE_REMOVED;
 140         }
 141         return update;
 142 }
 143
 144 void asl_start(struct whc *whc)
 145 {
 146         struct whc_qset *qset;
 147
 148         qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 149
 150         le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);
 151
 152         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
 153         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 154                       WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
 155                       1000, "start ASL");
 156 }
 157
 158 void asl_stop(struct whc *whc)
 159 {
 160         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
 161         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 162                       WUSBSTS_ASYNC_SCHED, 0,
 163                       1000, "stop ASL");
 164 }
 165
 166 /**
 167  * asl_update - request an ASL update and wait for the hardware to be synced
 168  * @whc: the WHCI HC
 169  * @wusbcmd: WUSBCMD value to start the update.
 170  *
 171  * If the WUSB HC is inactive (i.e., the ASL is stopped) then the
 172  * update must be skipped as the hardware may not respond to update
 173  * requests.
 174  */
 175 void asl_update(struct whc *whc, uint32_t wusbcmd)
 176 {
 177         struct wusbhc *wusbhc = &whc->wusbhc;
 178         long t;
 179
 180         mutex_lock(&wusbhc->mutex);
 181         if (wusbhc->active) {
 182                 whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
 183                 t = wait_event_timeout(
 184                         whc->async_list_wq,
 185                         (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0,
 186                         msecs_to_jiffies(1000));
 187                 if (t == 0)
 188                         whc_hw_error(whc, "ASL update timeout");
 189         }
 190         mutex_unlock(&wusbhc->mutex);
 191 }
 192
 193 /**
 194  * scan_async_work - scan the ASL for qsets to process.
 195  *
 196  * Process each qset in the ASL in turn and then signal the WHC that
 197  * the ASL has been updated.
 198  *
 199  * Then start, stop or update the asynchronous schedule as required.
 200  */
 201 void scan_async_work(struct work_struct *work)
 202 {
 203         struct whc *whc = container_of(work, struct whc, async_work);
 204         struct whc_qset *qset, *t;
 205         enum whc_update update = 0;
 206
 207         spin_lock_irq(&whc->lock);
 208
 209         /*
 210          * Transerve the software list backwards so new qsets can be
 211          * safely inserted into the ASL without making it non-circular.
 212          */
 213         list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
 214                 if (!qset->in_hw_list) {
 215                         asl_qset_insert(whc, qset);
 216                         update |= WHC_UPDATE_ADDED;
 217                 }
 218
 219                 update |= process_qset(whc, qset);
 220         }
 221
 222         spin_unlock_irq(&whc->lock);
 223
 224         if (update) {
 225                 uint32_t wusbcmd = WUSBCMD_ASYNC_UPDATED | WUSBCMD_ASYNC_SYNCED_DB;
 226                 if (update & WHC_UPDATE_REMOVED)
 227                         wusbcmd |= WUSBCMD_ASYNC_QSET_RM;
 228                 asl_update(whc, wusbcmd);
 229         }
 230
 231         /*
 232          * Now that the ASL is updated, complete the removal of any
 233          * removed qsets.
 234          *
 235          * If the qset was to be reset, do so and reinsert it into the
 236          * ASL if it has pending transfers.
 237          */
 238         spin_lock_irq(&whc->lock);
 239
 240         list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
 241                 qset_remove_complete(whc, qset);
 242                 if (qset->reset) {
 243                         qset_reset(whc, qset);
 244                         if (!list_empty(&qset->stds)) {
 245                                 asl_qset_insert_begin(whc, qset);
 246                                 queue_work(whc->workqueue, &whc->async_work);
 247                         }
 248                 }
 249         }
 250
 251         spin_unlock_irq(&whc->lock);
 252 }
 253
 254 /**
 255  * asl_urb_enqueue - queue an URB onto the asynchronous list (ASL).
 256  * @whc: the WHCI host controller
 257  * @urb: the URB to enqueue
 258  * @mem_flags: flags for any memory allocations
 259  *
 260  * The qset for the endpoint is obtained and the urb queued on to it.
 261  *
 262  * Work is scheduled to update the hardware's view of the ASL.
 263  */
 264 int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 265 {
 266         struct whc_qset *qset;
 267         int err;
 268         unsigned long flags;
 269
 270         spin_lock_irqsave(&whc->lock, flags);
 271
 272         err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 273         if (err < 0) {
 274                 spin_unlock_irqrestore(&whc->lock, flags);
 275                 return err;
 276         }
 277
 278         qset = get_qset(whc, urb, GFP_ATOMIC);
 279         if (qset == NULL)
 280                 err = -ENOMEM;
 281         else
 282                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 283         if (!err) {
 284                 if (!qset->in_sw_list && !qset->remove)
 285                         asl_qset_insert_begin(whc, qset);
 286         } else
 287                 usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
 288
 289         spin_unlock_irqrestore(&whc->lock, flags);
 290
 291         if (!err)
 292                 queue_work(whc->workqueue, &whc->async_work);
 293
 294         return err;
 295 }
 296
 297 /**
 298  * asl_urb_dequeue - remove an URB (qset) from the async list.
 299  * @whc: the WHCI host controller
 300  * @urb: the URB to dequeue
 301  * @status: the current status of the URB
 302  *
 303  * URBs that do yet have qTDs can simply be removed from the software
 304  * queue, otherwise the qset must be removed from the ASL so the qTDs
 305  * can be removed.
 306  */
 307 int asl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
 308 {
 309         struct whc_urb *wurb = urb->hcpriv;
 310         struct whc_qset *qset = wurb->qset;
 311         struct whc_std *std, *t;
 312         bool has_qtd = false;
 313         int ret;
 314         unsigned long flags;
 315
 316         spin_lock_irqsave(&whc->lock, flags);
 317
 318         ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
 319         if (ret < 0)
 320                 goto out;
 321
 322         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 323                 if (std->urb == urb) {
 324                         if (std->qtd)
 325                                 has_qtd = true;
 326                         qset_free_std(whc, std);
 327                 } else
 328                         std->qtd = NULL; /* so this std is re-added when the qset is */
 329         }
 330
 331         if (has_qtd) {
 332                 asl_qset_remove(whc, qset);
 333                 wurb->status = status;
 334                 wurb->is_async = true;
 335                 queue_work(whc->workqueue, &wurb->dequeue_work);
 336         } else
 337                 qset_remove_urb(whc, qset, urb, status);
 338 out:
 339         spin_unlock_irqrestore(&whc->lock, flags);
 340
 341         return ret;
 342 }
 343
 344 /**
 345  * asl_qset_delete - delete a qset from the ASL
 346  */
 347 void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
 348 {
 349         qset->remove = 1;
 350         queue_work(whc->workqueue, &whc->async_work);
 351         qset_delete(whc, qset);
 352 }
 353
 354 /**
 355  * asl_init - initialize the asynchronous schedule list
 356  *
 357  * A dummy qset with no qTDs is added to the ASL to simplify removing
 358  * qsets (no need to stop the ASL when the last qset is removed).
 359  */
 360 int asl_init(struct whc *whc)
 361 {
 362         struct whc_qset *qset;
 363
 364         qset = qset_alloc(whc, GFP_KERNEL);
 365         if (qset == NULL)
 366                 return -ENOMEM;
 367
 368         asl_qset_insert_begin(whc, qset);
 369         asl_qset_insert(whc, qset);
 370
 371         return 0;
 372 }
 373
 374 /**
 375  * asl_clean_up - free ASL resources
 376  *
 377  * The ASL is stopped and empty except for the dummy qset.
 378  */
 379 void asl_clean_up(struct whc *whc)
 380 {
 381         struct whc_qset *qset;
 382
 383         if (!list_empty(&whc->async_list)) {
 384                 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 385                 list_del(&qset->list_node);
 386                 qset_free(whc, qset);
 387         }
 388 }