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  66          * it's no longer valid.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                 int t;
  94
  95                 t = qset->td_start;
  96                 td = &qset->qtd[qset->td_start];
  97                 status = le32_to_cpu(td->status);
  98
  99                 /*
 100                  * Nothing to do with a still active qTD.
 101                  */
 102                 if (status & QTD_STS_ACTIVE)
 103                         break;
 104
 105                 if (status & QTD_STS_HALTED) {
 106                         /* Ug, an error. */
 107                         process_halted_qtd(whc, qset, td);
 108                         /* A halted qTD always triggers an update
 109                            because the qset was either removed or
 110                            reactivated. */
 111                         update |= WHC_UPDATE_UPDATED;
 112                         goto done;
 113                 }
 114
 115                 /* Mmm, a completed qTD. */
 116                 process_inactive_qtd(whc, qset, td);
 117         }
 118
 119         if (!qset->remove)
 120                 update |= qset_add_qtds(whc, qset);
 121
 122 done:
 123         /*
 124          * Remove this qset from the ASL if requested, but only if has
 125          * no qTDs.
 126          */
 127         if (qset->remove && qset->ntds == 0) {
 128                 asl_qset_remove(whc, qset);
 129                 update |= WHC_UPDATE_REMOVED;
 130         }
 131         return update;
 132 }
 133
 134 void asl_start(struct whc *whc)
 135 {
 136         struct whc_qset *qset;
 137
 138         qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 139
 140         le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);
 141
 142         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
 143         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 144                       WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
 145                       1000, "start ASL");
 146 }
 147
 148 void asl_stop(struct whc *whc)
 149 {
 150         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
 151         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 152                       WUSBSTS_ASYNC_SCHED, 0,
 153                       1000, "stop ASL");
 154 }
 155
 156 /**
 157  * asl_update - request an ASL update and wait for the hardware to be synced
 158  * @whc: the WHCI HC
 159  * @wusbcmd: WUSBCMD value to start the update.
 160  *
 161  * If the WUSB HC is inactive (i.e., the ASL is stopped) then the
 162  * update must be skipped as the hardware may not respond to update
 163  * requests.
 164  */
 165 void asl_update(struct whc *whc, uint32_t wusbcmd)
 166 {
 167         struct wusbhc *wusbhc = &whc->wusbhc;
 168         long t;
 169
 170         mutex_lock(&wusbhc->mutex);
 171         if (wusbhc->active) {
 172                 whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
 173                 t = wait_event_timeout(
 174                         whc->async_list_wq,
 175                         (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0,
 176                         msecs_to_jiffies(1000));
 177                 if (t == 0)
 178                         whc_hw_error(whc, "ASL update timeout");
 179         }
 180         mutex_unlock(&wusbhc->mutex);
 181 }
 182
 183 /**
 184  * scan_async_work - scan the ASL for qsets to process.
 185  *
 186  * Process each qset in the ASL in turn and then signal the WHC that
 187  * the ASL has been updated.
 188  *
 189  * Then start, stop or update the asynchronous schedule as required.
 190  */
 191 void scan_async_work(struct work_struct *work)
 192 {
 193         struct whc *whc = container_of(work, struct whc, async_work);
 194         struct whc_qset *qset, *t;
 195         enum whc_update update = 0;
 196
 197         spin_lock_irq(&whc->lock);
 198
 199         /*
 200          * Transerve the software list backwards so new qsets can be
 201          * safely inserted into the ASL without making it non-circular.
 202          */
 203         list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
 204                 if (!qset->in_hw_list) {
 205                         asl_qset_insert(whc, qset);
 206                         update |= WHC_UPDATE_ADDED;
 207                 }
 208
 209                 update |= process_qset(whc, qset);
 210         }
 211
 212         spin_unlock_irq(&whc->lock);
 213
 214         if (update) {
 215                 uint32_t wusbcmd = WUSBCMD_ASYNC_UPDATED | WUSBCMD_ASYNC_SYNCED_DB;
 216                 if (update & WHC_UPDATE_REMOVED)
 217                         wusbcmd |= WUSBCMD_ASYNC_QSET_RM;
 218                 asl_update(whc, wusbcmd);
 219         }
 220
 221         /*
 222          * Now that the ASL is updated, complete the removal of any
 223          * removed qsets.
 224          *
 225          * If the qset was to be reset, do so and reinsert it into the
 226          * ASL if it has pending transfers.
 227          */
 228         spin_lock_irq(&whc->lock);
 229
 230         list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
 231                 qset_remove_complete(whc, qset);
 232                 if (qset->reset) {
 233                         qset_reset(whc, qset);
 234                         if (!list_empty(&qset->stds)) {
 235                                 asl_qset_insert_begin(whc, qset);
 236                                 queue_work(whc->workqueue, &whc->async_work);
 237                         }
 238                 }
 239         }
 240
 241         spin_unlock_irq(&whc->lock);
 242 }
 243
 244 /**
 245  * asl_urb_enqueue - queue an URB onto the asynchronous list (ASL).
 246  * @whc: the WHCI host controller
 247  * @urb: the URB to enqueue
 248  * @mem_flags: flags for any memory allocations
 249  *
 250  * The qset for the endpoint is obtained and the urb queued on to it.
 251  *
 252  * Work is scheduled to update the hardware's view of the ASL.
 253  */
 254 int asl_urb_enqueue(struct whc *whc, struct urb *urb, gfp_t mem_flags)
 255 {
 256         struct whc_qset *qset;
 257         int err;
 258         unsigned long flags;
 259
 260         spin_lock_irqsave(&whc->lock, flags);
 261
 262         err = usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 263         if (err < 0) {
 264                 spin_unlock_irqrestore(&whc->lock, flags);
 265                 return err;
 266         }
 267
 268         qset = get_qset(whc, urb, GFP_ATOMIC);
 269         if (qset == NULL)
 270                 err = -ENOMEM;
 271         else
 272                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 273         if (!err) {
 274                 if (!qset->in_sw_list && !qset->remove)
 275                         asl_qset_insert_begin(whc, qset);
 276         } else
 277                 usb_hcd_unlink_urb_from_ep(&whc->wusbhc.usb_hcd, urb);
 278
 279         spin_unlock_irqrestore(&whc->lock, flags);
 280
 281         if (!err)
 282                 queue_work(whc->workqueue, &whc->async_work);
 283
 284         return err;
 285 }
 286
 287 /**
 288  * asl_urb_dequeue - remove an URB (qset) from the async list.
 289  * @whc: the WHCI host controller
 290  * @urb: the URB to dequeue
 291  * @status: the current status of the URB
 292  *
 293  * URBs that do yet have qTDs can simply be removed from the software
 294  * queue, otherwise the qset must be removed from the ASL so the qTDs
 295  * can be removed.
 296  */
 297 int asl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
 298 {
 299         struct whc_urb *wurb = urb->hcpriv;
 300         struct whc_qset *qset = wurb->qset;
 301         struct whc_std *std, *t;
 302         bool has_qtd = false;
 303         int ret;
 304         unsigned long flags;
 305
 306         spin_lock_irqsave(&whc->lock, flags);
 307
 308         ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
 309         if (ret < 0)
 310                 goto out;
 311
 312         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 313                 if (std->urb == urb) {
 314                         if (std->qtd)
 315                                 has_qtd = true;
 316                         qset_free_std(whc, std);
 317                 } else
 318                         std->qtd = NULL; /* so this std is re-added when the qset is */
 319         }
 320
 321         if (has_qtd) {
 322                 asl_qset_remove(whc, qset);
 323                 wurb->status = status;
 324                 wurb->is_async = true;
 325                 queue_work(whc->workqueue, &wurb->dequeue_work);
 326         } else
 327                 qset_remove_urb(whc, qset, urb, status);
 328 out:
 329         spin_unlock_irqrestore(&whc->lock, flags);
 330
 331         return ret;
 332 }
 333
 334 /**
 335  * asl_qset_delete - delete a qset from the ASL
 336  */
 337 void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
 338 {
 339         qset->remove = 1;
 340         queue_work(whc->workqueue, &whc->async_work);
 341         qset_delete(whc, qset);
 342 }
 343
 344 /**
 345  * asl_init - initialize the asynchronous schedule list
 346  *
 347  * A dummy qset with no qTDs is added to the ASL to simplify removing
 348  * qsets (no need to stop the ASL when the last qset is removed).
 349  */
 350 int asl_init(struct whc *whc)
 351 {
 352         struct whc_qset *qset;
 353
 354         qset = qset_alloc(whc, GFP_KERNEL);
 355         if (qset == NULL)
 356                 return -ENOMEM;
 357
 358         asl_qset_insert_begin(whc, qset);
 359         asl_qset_insert(whc, qset);
 360
 361         return 0;
 362 }
 363
 364 /**
 365  * asl_clean_up - free ASL resources
 366  *
 367  * The ASL is stopped and empty except for the dummy qset.
 368  */
 369 void asl_clean_up(struct whc *whc)
 370 {
 371         struct whc_qset *qset;
 372
 373         if (!list_empty(&whc->async_list)) {
 374                 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 375                 list_del(&qset->list_node);
 376                 qset_free(whc, qset);
 377         }
 378 }