drivers/usb/host/whci/asl.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Wireless Host Controller (WHC) asynchronous schedule management.
   4  *
   5  * Copyright (C) 2007 Cambridge Silicon Radio Ltd.
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/gfp.h>
   9 #include <linux/dma-mapping.h>
  10 #include <linux/uwb/umc.h>
  11 #include <linux/usb.h>
  12
  13 #include "../../wusbcore/wusbhc.h"
  14
  15 #include "whcd.h"
  16
  17 static void qset_get_next_prev(struct whc *whc, struct whc_qset *qset,
  18                                struct whc_qset **next, struct whc_qset **prev)
  19 {
  20         struct list_head *n, *p;
  21
  22         BUG_ON(list_empty(&whc->async_list));
  23
  24         n = qset->list_node.next;
  25         if (n == &whc->async_list)
  26                 n = n->next;
  27         p = qset->list_node.prev;
  28         if (p == &whc->async_list)
  29                 p = p->prev;
  30
  31         *next = container_of(n, struct whc_qset, list_node);
  32         *prev = container_of(p, struct whc_qset, list_node);
  33
  34 }
  35
  36 static void asl_qset_insert_begin(struct whc *whc, struct whc_qset *qset)
  37 {
  38         list_move(&qset->list_node, &whc->async_list);
  39         qset->in_sw_list = true;
  40 }
  41
  42 static void asl_qset_insert(struct whc *whc, struct whc_qset *qset)
  43 {
  44         struct whc_qset *next, *prev;
  45
  46         qset_clear(whc, qset);
  47
  48         /* Link into ASL. */
  49         qset_get_next_prev(whc, qset, &next, &prev);
  50         whc_qset_set_link_ptr(&qset->qh.link, next->qset_dma);
  51         whc_qset_set_link_ptr(&prev->qh.link, qset->qset_dma);
  52         qset->in_hw_list = true;
  53 }
  54
  55 static void asl_qset_remove(struct whc *whc, struct whc_qset *qset)
  56 {
  57         struct whc_qset *prev, *next;
  58
  59         qset_get_next_prev(whc, qset, &next, &prev);
  60
  61         list_move(&qset->list_node, &whc->async_removed_list);
  62         qset->in_sw_list = false;
  63
  64         /*
  65          * No more qsets in the ASL?  The caller must stop the ASL as
  66          * it's no longer valid.
  67          */
  68         if (list_empty(&whc->async_list))
  69                 return;
  70
  71         /* Remove from ASL. */
  72         whc_qset_set_link_ptr(&prev->qh.link, next->qset_dma);
  73         qset->in_hw_list = false;
  74 }
  75
  76 /**
  77  * process_qset - process any recently inactivated or halted qTDs in a
  78  * qset.
  79  *
  80  * After inactive qTDs are removed, new qTDs can be added if the
  81  * urb queue still contains URBs.
  82  *
  83  * Returns any additional WUSBCMD bits for the ASL sync command (i.e.,
  84  * WUSBCMD_ASYNC_QSET_RM if a halted qset was removed).
  85  */
  86 static uint32_t process_qset(struct whc *whc, struct whc_qset *qset)
  87 {
  88         enum whc_update update = 0;
  89         uint32_t status = 0;
  90
  91         while (qset->ntds) {
  92                 struct whc_qtd *td;
  93
  94                 td = &qset->qtd[qset->td_start];
  95                 status = le32_to_cpu(td->status);
  96
  97                 /*
  98                  * Nothing to do with a still active qTD.
  99                  */
 100                 if (status & QTD_STS_ACTIVE)
 101                         break;
 102
 103                 if (status & QTD_STS_HALTED) {
 104                         /* Ug, an error. */
 105                         process_halted_qtd(whc, qset, td);
 106                         /* A halted qTD always triggers an update
 107                            because the qset was either removed or
 108                            reactivated. */
 109                         update |= WHC_UPDATE_UPDATED;
 110                         goto done;
 111                 }
 112
 113                 /* Mmm, a completed qTD. */
 114                 process_inactive_qtd(whc, qset, td);
 115         }
 116
 117         if (!qset->remove)
 118                 update |= qset_add_qtds(whc, qset);
 119
 120 done:
 121         /*
 122          * Remove this qset from the ASL if requested, but only if has
 123          * no qTDs.
 124          */
 125         if (qset->remove && qset->ntds == 0) {
 126                 asl_qset_remove(whc, qset);
 127                 update |= WHC_UPDATE_REMOVED;
 128         }
 129         return update;
 130 }
 131
 132 void asl_start(struct whc *whc)
 133 {
 134         struct whc_qset *qset;
 135
 136         qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 137
 138         le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);
 139
 140         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
 141         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 142                       WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
 143                       1000, "start ASL");
 144 }
 145
 146 void asl_stop(struct whc *whc)
 147 {
 148         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
 149         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 150                       WUSBSTS_ASYNC_SCHED, 0,
 151                       1000, "stop ASL");
 152 }
 153
 154 /**
 155  * asl_update - request an ASL update and wait for the hardware to be synced
 156  * @whc: the WHCI HC
 157  * @wusbcmd: WUSBCMD value to start the update.
 158  *
 159  * If the WUSB HC is inactive (i.e., the ASL is stopped) then the
 160  * update must be skipped as the hardware may not respond to update
 161  * requests.
 162  */
 163 void asl_update(struct whc *whc, uint32_t wusbcmd)
 164 {
 165         struct wusbhc *wusbhc = &whc->wusbhc;
 166         long t;
 167
 168         mutex_lock(&wusbhc->mutex);
 169         if (wusbhc->active) {
 170                 whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
 171                 t = wait_event_timeout(
 172                         whc->async_list_wq,
 173                         (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0,
 174                         msecs_to_jiffies(1000));
 175                 if (t == 0)
 176                         whc_hw_error(whc, "ASL update timeout");
 177         }
 178         mutex_unlock(&wusbhc->mutex);
 179 }
 180
 181 /**
 182  * scan_async_work - scan the ASL for qsets to process.
 183  *
 184  * Process each qset in the ASL in turn and then signal the WHC that
 185  * the ASL has been updated.
 186  *
 187  * Then start, stop or update the asynchronous schedule as required.
 188  */
 189 void scan_async_work(struct work_struct *work)
 190 {
 191         struct whc *whc = container_of(work, struct whc, async_work);
 192         struct whc_qset *qset, *t;
 193         enum whc_update update = 0;
 194
 195         spin_lock_irq(&whc->lock);
 196
 197         /*
 198          * Transerve the software list backwards so new qsets can be
 199          * safely inserted into the ASL without making it non-circular.
 200          */
 201         list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
 202                 if (!qset->in_hw_list) {
 203                         asl_qset_insert(whc, qset);
 204                         update |= WHC_UPDATE_ADDED;
 205                 }
 206
 207                 update |= process_qset(whc, qset);
 208         }
 209
 210         spin_unlock_irq(&whc->lock);
 211
 212         if (update) {
 213                 uint32_t wusbcmd = WUSBCMD_ASYNC_UPDATED | WUSBCMD_ASYNC_SYNCED_DB;
 214                 if (update & WHC_UPDATE_REMOVED)
 215                         wusbcmd |= WUSBCMD_ASYNC_QSET_RM;
 216                 asl_update(whc, wusbcmd);
 217         }
 218
 219         /*
 220          * Now that the ASL is updated, complete the removal of any
 221          * removed qsets.
 222          *
 223          * If the qset was to be reset, do so and reinsert it into the
 224          * ASL if it has pending transfers.
 225          */
 226         spin_lock_irq(&whc->lock);
 227
 228         list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
 229                 qset_remove_complete(whc, qset);
 230                 if (qset->reset) {
 231                         qset_reset(whc, qset);
 232                         if (!list_empty(&qset->stds)) {
 233                                 asl_qset_insert_begin(whc, qset);
 234                                 queue_work(whc->workqueue, &whc->async_work);
 235                         }
 236                 }
 237         }
 238
 239         spin_unlock_irq(&whc->lock);
 240 }
 241
 242 /**
 243  * asl_urb_enqueue - queue an URB onto the asynchronous list (ASL).
 244  * @whc: the WHCI host controller
 245  * @urb: the URB to enqueue
 246  * @mem_flags: flags for any memory allocations
 247  *
 248  * The qset for the endpoint is obtained and the urb queued on to it.
 249  *
 250  * Work is scheduled to update the hardware's view of the ASL.
 251  */
 252 int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 253 {
 254         struct whc_qset *qset;
 255         int err;
 256         unsigned long flags;
 257
 258         spin_lock_irqsave(&whc->lock, flags);
 259
 260         err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 261         if (err < 0) {
 262                 spin_unlock_irqrestore(&whc->lock, flags);
 263                 return err;
 264         }
 265
 266         qset = get_qset(whc, urb, GFP_ATOMIC);
 267         if (qset == NULL)
 268                 err = -ENOMEM;
 269         else
 270                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 271         if (!err) {
 272                 if (!qset->in_sw_list && !qset->remove)
 273                         asl_qset_insert_begin(whc, qset);
 274         } else
 275                 usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
 276
 277         spin_unlock_irqrestore(&whc->lock, flags);
 278
 279         if (!err)
 280                 queue_work(whc->workqueue, &whc->async_work);
 281
 282         return err;
 283 }
 284
 285 /**
 286  * asl_urb_dequeue - remove an URB (qset) from the async list.
 287  * @whc: the WHCI host controller
 288  * @urb: the URB to dequeue
 289  * @status: the current status of the URB
 290  *
 291  * URBs that do yet have qTDs can simply be removed from the software
 292  * queue, otherwise the qset must be removed from the ASL so the qTDs
 293  * can be removed.
 294  */
 295 int asl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
 296 {
 297         struct whc_urb *wurb = urb->hcpriv;
 298         struct whc_qset *qset = wurb->qset;
 299         struct whc_std *std, *t;
 300         bool has_qtd = false;
 301         int ret;
 302         unsigned long flags;
 303
 304         spin_lock_irqsave(&whc->lock, flags);
 305
 306         ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
 307         if (ret < 0)
 308                 goto out;
 309
 310         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 311                 if (std->urb == urb) {
 312                         if (std->qtd)
 313                                 has_qtd = true;
 314                         qset_free_std(whc, std);
 315                 } else
 316                         std->qtd = NULL; /* so this std is re-added when the qset is */
 317         }
 318
 319         if (has_qtd) {
 320                 asl_qset_remove(whc, qset);
 321                 wurb->status = status;
 322                 wurb->is_async = true;
 323                 queue_work(whc->workqueue, &wurb->dequeue_work);
 324         } else
 325                 qset_remove_urb(whc, qset, urb, status);
 326 out:
 327         spin_unlock_irqrestore(&whc->lock, flags);
 328
 329         return ret;
 330 }
 331
 332 /**
 333  * asl_qset_delete - delete a qset from the ASL
 334  */
 335 void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
 336 {
 337         qset->remove = 1;
 338         queue_work(whc->workqueue, &whc->async_work);
 339         qset_delete(whc, qset);
 340 }
 341
 342 /**
 343  * asl_init - initialize the asynchronous schedule list
 344  *
 345  * A dummy qset with no qTDs is added to the ASL to simplify removing
 346  * qsets (no need to stop the ASL when the last qset is removed).
 347  */
 348 int asl_init(struct whc *whc)
 349 {
 350         struct whc_qset *qset;
 351
 352         qset = qset_alloc(whc, GFP_KERNEL);
 353         if (qset == NULL)
 354                 return -ENOMEM;
 355
 356         asl_qset_insert_begin(whc, qset);
 357         asl_qset_insert(whc, qset);
 358
 359         return 0;
 360 }
 361
 362 /**
 363  * asl_clean_up - free ASL resources
 364  *
 365  * The ASL is stopped and empty except for the dummy qset.
 366  */
 367 void asl_clean_up(struct whc *whc)
 368 {
 369         struct whc_qset *qset;
 370
 371         if (!list_empty(&whc->async_list)) {
 372                 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 373                 list_del(&qset->list_node);
 374                 qset_free(whc, qset);
 375         }
 376 }