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                         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
 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
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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  */
 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 }