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