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 #define D_LOCAL 0
  23 #include <linux/uwb/debug.h>
  24
  25 #include "../../wusbcore/wusbhc.h"
  26
  27 #include "whcd.h"
  28
  29 #if D_LOCAL >= 4
  30 static void dump_asl(struct whc *whc, const char *tag)
  31 {
  32         struct device *dev = &whc->umc->dev;
  33         struct whc_qset *qset;
  34
  35         d_printf(4, dev, "ASL %s\n", tag);
  36
  37         list_for_each_entry(qset, &whc->async_list, list_node) {
  38                 dump_qset(qset, dev);
  39         }
  40 }
  41 #else
  42 static inline void dump_asl(struct whc *whc, const char *tag)
  43 {
  44 }
  45 #endif
  46
  47
  48 static void qset_get_next_prev(struct whc *whc, struct whc_qset *qset,
  49                                struct whc_qset **next, struct whc_qset **prev)
  50 {
  51         struct list_head *n, *p;
  52
  53         BUG_ON(list_empty(&whc->async_list));
  54
  55         n = qset->list_node.next;
  56         if (n == &whc->async_list)
  57                 n = n->next;
  58         p = qset->list_node.prev;
  59         if (p == &whc->async_list)
  60                 p = p->prev;
  61
  62         *next = container_of(n, struct whc_qset, list_node);
  63         *prev = container_of(p, struct whc_qset, list_node);
  64
  65 }
  66
  67 static void asl_qset_insert_begin(struct whc *whc, struct whc_qset *qset)
  68 {
  69         list_move(&qset->list_node, &whc->async_list);
  70         qset->in_sw_list = true;
  71 }
  72
  73 static void asl_qset_insert(struct whc *whc, struct whc_qset *qset)
  74 {
  75         struct whc_qset *next, *prev;
  76
  77         qset_clear(whc, qset);
  78
  79         /* Link into ASL. */
  80         qset_get_next_prev(whc, qset, &next, &prev);
  81         whc_qset_set_link_ptr(&qset->qh.link, next->qset_dma);
  82         whc_qset_set_link_ptr(&prev->qh.link, qset->qset_dma);
  83         qset->in_hw_list = true;
  84 }
  85
  86 static void asl_qset_remove(struct whc *whc, struct whc_qset *qset)
  87 {
  88         struct whc_qset *prev, *next;
  89
  90         qset_get_next_prev(whc, qset, &next, &prev);
  91
  92         list_move(&qset->list_node, &whc->async_removed_list);
  93         qset->in_sw_list = false;
  94
  95         /*
  96          * No more qsets in the ASL?  The caller must stop the ASL as
  97          * it's no longer valid.
  98          */
  99         if (list_empty(&whc->async_list))
 100                 return;
 101
 102         /* Remove from ASL. */
 103         whc_qset_set_link_ptr(&prev->qh.link, next->qset_dma);
 104         qset->in_hw_list = false;
 105 }
 106
 107 /**
 108  * process_qset - process any recently inactivated or halted qTDs in a
 109  * qset.
 110  *
 111  * After inactive qTDs are removed, new qTDs can be added if the
 112  * urb queue still contains URBs.
 113  *
 114  * Returns any additional WUSBCMD bits for the ASL sync command (i.e.,
 115  * WUSBCMD_ASYNC_QSET_RM if a halted qset was removed).
 116  */
 117 static uint32_t process_qset(struct whc *whc, struct whc_qset *qset)
 118 {
 119         enum whc_update update = 0;
 120         uint32_t status = 0;
 121
 122         while (qset->ntds) {
 123                 struct whc_qtd *td;
 124                 int t;
 125
 126                 t = qset->td_start;
 127                 td = &qset->qtd[qset->td_start];
 128                 status = le32_to_cpu(td->status);
 129
 130                 /*
 131                  * Nothing to do with a still active qTD.
 132                  */
 133                 if (status & QTD_STS_ACTIVE)
 134                         break;
 135
 136                 if (status & QTD_STS_HALTED) {
 137                         /* Ug, an error. */
 138                         process_halted_qtd(whc, qset, td);
 139                         goto done;
 140                 }
 141
 142                 /* Mmm, a completed qTD. */
 143                 process_inactive_qtd(whc, qset, td);
 144         }
 145
 146         update |= qset_add_qtds(whc, qset);
 147
 148 done:
 149         /*
 150          * Remove this qset from the ASL if requested, but only if has
 151          * no qTDs.
 152          */
 153         if (qset->remove && qset->ntds == 0) {
 154                 asl_qset_remove(whc, qset);
 155                 update |= WHC_UPDATE_REMOVED;
 156         }
 157         return update;
 158 }
 159
 160 void asl_start(struct whc *whc)
 161 {
 162         struct whc_qset *qset;
 163
 164         qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 165
 166         le_writeq(qset->qset_dma | QH_LINK_NTDS(8), whc->base + WUSBASYNCLISTADDR);
 167
 168         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, WUSBCMD_ASYNC_EN);
 169         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 170                       WUSBSTS_ASYNC_SCHED, WUSBSTS_ASYNC_SCHED,
 171                       1000, "start ASL");
 172 }
 173
 174 void asl_stop(struct whc *whc)
 175 {
 176         whc_write_wusbcmd(whc, WUSBCMD_ASYNC_EN, 0);
 177         whci_wait_for(&whc->umc->dev, whc->base + WUSBSTS,
 178                       WUSBSTS_ASYNC_SCHED, 0,
 179                       1000, "stop ASL");
 180 }
 181
 182 void asl_update(struct whc *whc, uint32_t wusbcmd)
 183 {
 184         whc_write_wusbcmd(whc, wusbcmd, wusbcmd);
 185         wait_event(whc->async_list_wq,
 186                    (le_readl(whc->base + WUSBCMD) & WUSBCMD_ASYNC_UPDATED) == 0);
 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         dump_asl(whc, "before processing");
 206
 207         /*
 208          * Transerve the software list backwards so new qsets can be
 209          * safely inserted into the ASL without making it non-circular.
 210          */
 211         list_for_each_entry_safe_reverse(qset, t, &whc->async_list, list_node) {
 212                 if (!qset->in_hw_list) {
 213                         asl_qset_insert(whc, qset);
 214                         update |= WHC_UPDATE_ADDED;
 215                 }
 216
 217                 update |= process_qset(whc, qset);
 218         }
 219
 220         dump_asl(whc, "after processing");
 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         spin_lock(&whc->lock);
 236
 237         list_for_each_entry_safe(qset, t, &whc->async_removed_list, list_node) {
 238                 qset_remove_complete(whc, qset);
 239         }
 240
 241         spin_unlock(&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         qset = get_qset(whc, urb, GFP_ATOMIC);
 263         if (qset == NULL)
 264                 err = -ENOMEM;
 265         else
 266                 err = qset_add_urb(whc, qset, urb, GFP_ATOMIC);
 267         if (!err) {
 268                 usb_hcd_link_urb_to_ep(&whc->wusbhc.usb_hcd, urb);
 269                 if (!qset->in_sw_list)
 270                         asl_qset_insert_begin(whc, qset);
 271         }
 272
 273         spin_unlock_irqrestore(&whc->lock, flags);
 274
 275         if (!err)
 276                 queue_work(whc->workqueue, &whc->async_work);
 277
 278         return 0;
 279 }
 280
 281 /**
 282  * asl_urb_dequeue - remove an URB (qset) from the async list.
 283  * @whc: the WHCI host controller
 284  * @urb: the URB to dequeue
 285  * @status: the current status of the URB
 286  *
 287  * URBs that do yet have qTDs can simply be removed from the software
 288  * queue, otherwise the qset must be removed from the ASL so the qTDs
 289  * can be removed.
 290  */
 291 int asl_urb_dequeue(struct whc *whc, struct urb *urb, int status)
 292 {
 293         struct whc_urb *wurb = urb->hcpriv;
 294         struct whc_qset *qset = wurb->qset;
 295         struct whc_std *std, *t;
 296         int ret;
 297         unsigned long flags;
 298
 299         spin_lock_irqsave(&whc->lock, flags);
 300
 301         ret = usb_hcd_check_unlink_urb(&whc->wusbhc.usb_hcd, urb, status);
 302         if (ret < 0)
 303                 goto out;
 304
 305         list_for_each_entry_safe(std, t, &qset->stds, list_node) {
 306                 if (std->urb == urb)
 307                         qset_free_std(whc, std);
 308                 else
 309                         std->qtd = NULL; /* so this std is re-added when the qset is */
 310         }
 311
 312         asl_qset_remove(whc, qset);
 313         wurb->status = status;
 314         wurb->is_async = true;
 315         queue_work(whc->workqueue, &wurb->dequeue_work);
 316
 317 out:
 318         spin_unlock_irqrestore(&whc->lock, flags);
 319
 320         return ret;
 321 }
 322
 323 /**
 324  * asl_qset_delete - delete a qset from the ASL
 325  */
 326 void asl_qset_delete(struct whc *whc, struct whc_qset *qset)
 327 {
 328         qset->remove = 1;
 329         queue_work(whc->workqueue, &whc->async_work);
 330         qset_delete(whc, qset);
 331 }
 332
 333 /**
 334  * asl_init - initialize the asynchronous schedule list
 335  *
 336  * A dummy qset with no qTDs is added to the ASL to simplify removing
 337  * qsets (no need to stop the ASL when the last qset is removed).
 338  */
 339 int asl_init(struct whc *whc)
 340 {
 341         struct whc_qset *qset;
 342
 343         qset = qset_alloc(whc, GFP_KERNEL);
 344         if (qset == NULL)
 345                 return -ENOMEM;
 346
 347         asl_qset_insert_begin(whc, qset);
 348         asl_qset_insert(whc, qset);
 349
 350         return 0;
 351 }
 352
 353 /**
 354  * asl_clean_up - free ASL resources
 355  *
 356  * The ASL is stopped and empty except for the dummy qset.
 357  */
 358 void asl_clean_up(struct whc *whc)
 359 {
 360         struct whc_qset *qset;
 361
 362         if (!list_empty(&whc->async_list)) {
 363                 qset = list_first_entry(&whc->async_list, struct whc_qset, list_node);
 364                 list_del(&qset->list_node);
 365                 qset_free(whc, qset);
 366         }
 367 }