drivers/infiniband/hw/qib/qib_user_sdma.c

   1 /*
   2  * Copyright (c) 2007, 2008, 2009 QLogic Corporation. All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  */
  32 #include <linux/mm.h>
  33 #include <linux/types.h>
  34 #include <linux/device.h>
  35 #include <linux/dmapool.h>
  36 #include <linux/slab.h>
  37 #include <linux/list.h>
  38 #include <linux/highmem.h>
  39 #include <linux/io.h>
  40 #include <linux/uio.h>
  41 #include <linux/rbtree.h>
  42 #include <linux/spinlock.h>
  43 #include <linux/delay.h>
  44
  45 #include "qib.h"
  46 #include "qib_user_sdma.h"
  47
  48 /* minimum size of header */
  49 #define QIB_USER_SDMA_MIN_HEADER_LENGTH 64
  50 /* expected size of headers (for dma_pool) */
  51 #define QIB_USER_SDMA_EXP_HEADER_LENGTH 64
  52 /* attempt to drain the queue for 5secs */
  53 #define QIB_USER_SDMA_DRAIN_TIMEOUT 250
  54
  55 /*
  56  * track how many times a process open this driver.
  57  */
  58 static struct rb_root qib_user_sdma_rb_root = RB_ROOT;
  59
  60 struct qib_user_sdma_rb_node {
  61         struct rb_node node;
  62         int refcount;
  63         pid_t pid;
  64 };
  65
  66 struct qib_user_sdma_pkt {
  67         struct list_head list;  /* list element */
  68
  69         u8  tiddma;             /* if this is NEW tid-sdma */
  70         u8  largepkt;           /* this is large pkt from kmalloc */
  71         u16 frag_size;          /* frag size used by PSM */
  72         u16 index;              /* last header index or push index */
  73         u16 naddr;              /* dimension of addr (1..3) ... */
  74         u16 addrlimit;          /* addr array size */
  75         u16 tidsmidx;           /* current tidsm index */
  76         u16 tidsmcount;         /* tidsm array item count */
  77         u16 payload_size;       /* payload size so far for header */
  78         u32 bytes_togo;         /* bytes for processing */
  79         u32 counter;            /* sdma pkts queued counter for this entry */
  80         struct qib_tid_session_member *tidsm;   /* tid session member array */
  81         struct qib_user_sdma_queue *pq; /* which pq this pkt belongs to */
  82         u64 added;              /* global descq number of entries */
  83
  84         struct {
  85                 u16 offset;                     /* offset for kvaddr, addr */
  86                 u16 length;                     /* length in page */
  87                 u16 first_desc;                 /* first desc */
  88                 u16 last_desc;                  /* last desc */
  89                 u16 put_page;                   /* should we put_page? */
  90                 u16 dma_mapped;                 /* is page dma_mapped? */
  91                 u16 dma_length;                 /* for dma_unmap_page() */
  92                 u16 padding;
  93                 struct page *page;              /* may be NULL (coherent mem) */
  94                 void *kvaddr;                   /* FIXME: only for pio hack */
  95                 dma_addr_t addr;
  96         } addr[4];   /* max pages, any more and we coalesce */
  97 };
  98
  99 struct qib_user_sdma_queue {
 100         /*
 101          * pkts sent to dma engine are queued on this
 102          * list head.  the type of the elements of this
 103          * list are struct qib_user_sdma_pkt...
 104          */
 105         struct list_head sent;
 106
 107         /*
 108          * Because above list will be accessed by both process and
 109          * signal handler, we need a spinlock for it.
 110          */
 111         spinlock_t sent_lock ____cacheline_aligned_in_smp;
 112
 113         /* headers with expected length are allocated from here... */
 114         char header_cache_name[64];
 115         struct dma_pool *header_cache;
 116
 117         /* packets are allocated from the slab cache... */
 118         char pkt_slab_name[64];
 119         struct kmem_cache *pkt_slab;
 120
 121         /* as packets go on the queued queue, they are counted... */
 122         u32 counter;
 123         u32 sent_counter;
 124         /* pending packets, not sending yet */
 125         u32 num_pending;
 126         /* sending packets, not complete yet */
 127         u32 num_sending;
 128         /* global descq number of entry of last sending packet */
 129         u64 added;
 130
 131         /* dma page table */
 132         struct rb_root dma_pages_root;
 133
 134         struct qib_user_sdma_rb_node *sdma_rb_node;
 135
 136         /* protect everything above... */
 137         struct mutex lock;
 138 };
 139
 140 static struct qib_user_sdma_rb_node *
 141 qib_user_sdma_rb_search(struct rb_root *root, pid_t pid)
 142 {
 143         struct qib_user_sdma_rb_node *sdma_rb_node;
 144         struct rb_node *node = root->rb_node;
 145
 146         while (node) {
 147                 sdma_rb_node = rb_entry(node, struct qib_user_sdma_rb_node,
 148                                         node);
 149                 if (pid < sdma_rb_node->pid)
 150                         node = node->rb_left;
 151                 else if (pid > sdma_rb_node->pid)
 152                         node = node->rb_right;
 153                 else
 154                         return sdma_rb_node;
 155         }
 156         return NULL;
 157 }
 158
 159 static int
 160 qib_user_sdma_rb_insert(struct rb_root *root, struct qib_user_sdma_rb_node *new)
 161 {
 162         struct rb_node **node = &(root->rb_node);
 163         struct rb_node *parent = NULL;
 164         struct qib_user_sdma_rb_node *got;
 165
 166         while (*node) {
 167                 got = rb_entry(*node, struct qib_user_sdma_rb_node, node);
 168                 parent = *node;
 169                 if (new->pid < got->pid)
 170                         node = &((*node)->rb_left);
 171                 else if (new->pid > got->pid)
 172                         node = &((*node)->rb_right);
 173                 else
 174                         return 0;
 175         }
 176
 177         rb_link_node(&new->node, parent, node);
 178         rb_insert_color(&new->node, root);
 179         return 1;
 180 }
 181
 182 struct qib_user_sdma_queue *
 183 qib_user_sdma_queue_create(struct device *dev, int unit, int ctxt, int sctxt)
 184 {
 185         struct qib_user_sdma_queue *pq =
 186                 kmalloc(sizeof(struct qib_user_sdma_queue), GFP_KERNEL);
 187         struct qib_user_sdma_rb_node *sdma_rb_node;
 188
 189         if (!pq)
 190                 goto done;
 191
 192         pq->counter = 0;
 193         pq->sent_counter = 0;
 194         pq->num_pending = 0;
 195         pq->num_sending = 0;
 196         pq->added = 0;
 197         pq->sdma_rb_node = NULL;
 198
 199         INIT_LIST_HEAD(&pq->sent);
 200         spin_lock_init(&pq->sent_lock);
 201         mutex_init(&pq->lock);
 202
 203         snprintf(pq->pkt_slab_name, sizeof(pq->pkt_slab_name),
 204                  "qib-user-sdma-pkts-%u-%02u.%02u", unit, ctxt, sctxt);
 205         pq->pkt_slab = kmem_cache_create(pq->pkt_slab_name,
 206                                          sizeof(struct qib_user_sdma_pkt),
 207                                          0, 0, NULL);
 208
 209         if (!pq->pkt_slab)
 210                 goto err_kfree;
 211
 212         snprintf(pq->header_cache_name, sizeof(pq->header_cache_name),
 213                  "qib-user-sdma-headers-%u-%02u.%02u", unit, ctxt, sctxt);
 214         pq->header_cache = dma_pool_create(pq->header_cache_name,
 215                                            dev,
 216                                            QIB_USER_SDMA_EXP_HEADER_LENGTH,
 217                                            4, 0);
 218         if (!pq->header_cache)
 219                 goto err_slab;
 220
 221         pq->dma_pages_root = RB_ROOT;
 222
 223         sdma_rb_node = qib_user_sdma_rb_search(&qib_user_sdma_rb_root,
 224                                         current->pid);
 225         if (sdma_rb_node) {
 226                 sdma_rb_node->refcount++;
 227         } else {
 228                 sdma_rb_node = kmalloc(sizeof(
 229                         struct qib_user_sdma_rb_node), GFP_KERNEL);
 230                 if (!sdma_rb_node)
 231                         goto err_rb;
 232
 233                 sdma_rb_node->refcount = 1;
 234                 sdma_rb_node->pid = current->pid;
 235
 236                 qib_user_sdma_rb_insert(&qib_user_sdma_rb_root, sdma_rb_node);
 237         }
 238         pq->sdma_rb_node = sdma_rb_node;
 239
 240         goto done;
 241
 242 err_rb:
 243         dma_pool_destroy(pq->header_cache);
 244 err_slab:
 245         kmem_cache_destroy(pq->pkt_slab);
 246 err_kfree:
 247         kfree(pq);
 248         pq = NULL;
 249
 250 done:
 251         return pq;
 252 }
 253
 254 static void qib_user_sdma_init_frag(struct qib_user_sdma_pkt *pkt,
 255                                     int i, u16 offset, u16 len,
 256                                     u16 first_desc, u16 last_desc,
 257                                     u16 put_page, u16 dma_mapped,
 258                                     struct page *page, void *kvaddr,
 259                                     dma_addr_t dma_addr, u16 dma_length)
 260 {
 261         pkt->addr[i].offset = offset;
 262         pkt->addr[i].length = len;
 263         pkt->addr[i].first_desc = first_desc;
 264         pkt->addr[i].last_desc = last_desc;
 265         pkt->addr[i].put_page = put_page;
 266         pkt->addr[i].dma_mapped = dma_mapped;
 267         pkt->addr[i].page = page;
 268         pkt->addr[i].kvaddr = kvaddr;
 269         pkt->addr[i].addr = dma_addr;
 270         pkt->addr[i].dma_length = dma_length;
 271 }
 272
 273 static void *qib_user_sdma_alloc_header(struct qib_user_sdma_queue *pq,
 274                                 size_t len, dma_addr_t *dma_addr)
 275 {
 276         void *hdr;
 277
 278         if (len == QIB_USER_SDMA_EXP_HEADER_LENGTH)
 279                 hdr = dma_pool_alloc(pq->header_cache, GFP_KERNEL,
 280                                              dma_addr);
 281         else
 282                 hdr = NULL;
 283
 284         if (!hdr) {
 285                 hdr = kmalloc(len, GFP_KERNEL);
 286                 if (!hdr)
 287                         return NULL;
 288
 289                 *dma_addr = 0;
 290         }
 291
 292         return hdr;
 293 }
 294
 295 static int qib_user_sdma_page_to_frags(const struct qib_devdata *dd,
 296                                        struct qib_user_sdma_queue *pq,
 297                                        struct qib_user_sdma_pkt *pkt,
 298                                        struct page *page, u16 put,
 299                                        u16 offset, u16 len, void *kvaddr)
 300 {
 301         __le16 *pbc16;
 302         void *pbcvaddr;
 303         struct qib_message_header *hdr;
 304         u16 newlen, pbclen, lastdesc, dma_mapped;
 305         u32 vcto;
 306         union qib_seqnum seqnum;
 307         dma_addr_t pbcdaddr;
 308         dma_addr_t dma_addr =
 309                 dma_map_page(&dd->pcidev->dev,
 310                         page, offset, len, DMA_TO_DEVICE);
 311         int ret = 0;
 312
 313         if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
 314                 /*
 315                  * dma mapping error, pkt has not managed
 316                  * this page yet, return the page here so
 317                  * the caller can ignore this page.
 318                  */
 319                 if (put) {
 320                         put_page(page);
 321                 } else {
 322                         /* coalesce case */
 323                         kunmap(page);
 324                         __free_page(page);
 325                 }
 326                 ret = -ENOMEM;
 327                 goto done;
 328         }
 329         offset = 0;
 330         dma_mapped = 1;
 331
 332
 333 next_fragment:
 334
 335         /*
 336          * In tid-sdma, the transfer length is restricted by
 337          * receiver side current tid page length.
 338          */
 339         if (pkt->tiddma && len > pkt->tidsm[pkt->tidsmidx].length)
 340                 newlen = pkt->tidsm[pkt->tidsmidx].length;
 341         else
 342                 newlen = len;
 343
 344         /*
 345          * Then the transfer length is restricted by MTU.
 346          * the last descriptor flag is determined by:
 347          * 1. the current packet is at frag size length.
 348          * 2. the current tid page is done if tid-sdma.
 349          * 3. there is no more byte togo if sdma.
 350          */
 351         lastdesc = 0;
 352         if ((pkt->payload_size + newlen) >= pkt->frag_size) {
 353                 newlen = pkt->frag_size - pkt->payload_size;
 354                 lastdesc = 1;
 355         } else if (pkt->tiddma) {
 356                 if (newlen == pkt->tidsm[pkt->tidsmidx].length)
 357                         lastdesc = 1;
 358         } else {
 359                 if (newlen == pkt->bytes_togo)
 360                         lastdesc = 1;
 361         }
 362
 363         /* fill the next fragment in this page */
 364         qib_user_sdma_init_frag(pkt, pkt->naddr, /* index */
 365                 offset, newlen,         /* offset, len */
 366                 0, lastdesc,            /* first last desc */
 367                 put, dma_mapped,        /* put page, dma mapped */
 368                 page, kvaddr,           /* struct page, virt addr */
 369                 dma_addr, len);         /* dma addr, dma length */
 370         pkt->bytes_togo -= newlen;
 371         pkt->payload_size += newlen;
 372         pkt->naddr++;
 373         if (pkt->naddr == pkt->addrlimit) {
 374                 ret = -EFAULT;
 375                 goto done;
 376         }
 377
 378         /* If there is no more byte togo. (lastdesc==1) */
 379         if (pkt->bytes_togo == 0) {
 380                 /* The packet is done, header is not dma mapped yet.
 381                  * it should be from kmalloc */
 382                 if (!pkt->addr[pkt->index].addr) {
 383                         pkt->addr[pkt->index].addr =
 384                                 dma_map_single(&dd->pcidev->dev,
 385                                         pkt->addr[pkt->index].kvaddr,
 386                                         pkt->addr[pkt->index].dma_length,
 387                                         DMA_TO_DEVICE);
 388                         if (dma_mapping_error(&dd->pcidev->dev,
 389                                         pkt->addr[pkt->index].addr)) {
 390                                 ret = -ENOMEM;
 391                                 goto done;
 392                         }
 393                         pkt->addr[pkt->index].dma_mapped = 1;
 394                 }
 395
 396                 goto done;
 397         }
 398
 399         /* If tid-sdma, advance tid info. */
 400         if (pkt->tiddma) {
 401                 pkt->tidsm[pkt->tidsmidx].length -= newlen;
 402                 if (pkt->tidsm[pkt->tidsmidx].length) {
 403                         pkt->tidsm[pkt->tidsmidx].offset += newlen;
 404                 } else {
 405                         pkt->tidsmidx++;
 406                         if (pkt->tidsmidx == pkt->tidsmcount) {
 407                                 ret = -EFAULT;
 408                                 goto done;
 409                         }
 410                 }
 411         }
 412
 413         /*
 414          * If this is NOT the last descriptor. (newlen==len)
 415          * the current packet is not done yet, but the current
 416          * send side page is done.
 417          */
 418         if (lastdesc == 0)
 419                 goto done;
 420
 421         /*
 422          * If running this driver under PSM with message size
 423          * fitting into one transfer unit, it is not possible
 424          * to pass this line. otherwise, it is a buggggg.
 425          */
 426
 427         /*
 428          * Since the current packet is done, and there are more
 429          * bytes togo, we need to create a new sdma header, copying
 430          * from previous sdma header and modify both.
 431          */
 432         pbclen = pkt->addr[pkt->index].length;
 433         pbcvaddr = qib_user_sdma_alloc_header(pq, pbclen, &pbcdaddr);
 434         if (!pbcvaddr) {
 435                 ret = -ENOMEM;
 436                 goto done;
 437         }
 438         /* Copy the previous sdma header to new sdma header */
 439         pbc16 = (__le16 *)pkt->addr[pkt->index].kvaddr;
 440         memcpy(pbcvaddr, pbc16, pbclen);
 441
 442         /* Modify the previous sdma header */
 443         hdr = (struct qib_message_header *)&pbc16[4];
 444
 445         /* New pbc length */
 446         pbc16[0] = cpu_to_le16(le16_to_cpu(pbc16[0])-(pkt->bytes_togo>>2));
 447
 448         /* New packet length */
 449         hdr->lrh[2] = cpu_to_be16(le16_to_cpu(pbc16[0]));
 450
 451         if (pkt->tiddma) {
 452                 /* turn on the header suppression */
 453                 hdr->iph.pkt_flags =
 454                         cpu_to_le16(le16_to_cpu(hdr->iph.pkt_flags)|0x2);
 455                 /* turn off ACK_REQ: 0x04 and EXPECTED_DONE: 0x20 */
 456                 hdr->flags &= ~(0x04|0x20);
 457         } else {
 458                 /* turn off extra bytes: 20-21 bits */
 459                 hdr->bth[0] = cpu_to_be32(be32_to_cpu(hdr->bth[0])&0xFFCFFFFF);
 460                 /* turn off ACK_REQ: 0x04 */
 461                 hdr->flags &= ~(0x04);
 462         }
 463
 464         /* New kdeth checksum */
 465         vcto = le32_to_cpu(hdr->iph.ver_ctxt_tid_offset);
 466         hdr->iph.chksum = cpu_to_le16(QIB_LRH_BTH +
 467                 be16_to_cpu(hdr->lrh[2]) -
 468                 ((vcto>>16)&0xFFFF) - (vcto&0xFFFF) -
 469                 le16_to_cpu(hdr->iph.pkt_flags));
 470
 471         /* The packet is done, header is not dma mapped yet.
 472          * it should be from kmalloc */
 473         if (!pkt->addr[pkt->index].addr) {
 474                 pkt->addr[pkt->index].addr =
 475                         dma_map_single(&dd->pcidev->dev,
 476                                 pkt->addr[pkt->index].kvaddr,
 477                                 pkt->addr[pkt->index].dma_length,
 478                                 DMA_TO_DEVICE);
 479                 if (dma_mapping_error(&dd->pcidev->dev,
 480                                 pkt->addr[pkt->index].addr)) {
 481                         ret = -ENOMEM;
 482                         goto done;
 483                 }
 484                 pkt->addr[pkt->index].dma_mapped = 1;
 485         }
 486
 487         /* Modify the new sdma header */
 488         pbc16 = (__le16 *)pbcvaddr;
 489         hdr = (struct qib_message_header *)&pbc16[4];
 490
 491         /* New pbc length */
 492         pbc16[0] = cpu_to_le16(le16_to_cpu(pbc16[0])-(pkt->payload_size>>2));
 493
 494         /* New packet length */
 495         hdr->lrh[2] = cpu_to_be16(le16_to_cpu(pbc16[0]));
 496
 497         if (pkt->tiddma) {
 498                 /* Set new tid and offset for new sdma header */
 499                 hdr->iph.ver_ctxt_tid_offset = cpu_to_le32(
 500                         (le32_to_cpu(hdr->iph.ver_ctxt_tid_offset)&0xFF000000) +
 501                         (pkt->tidsm[pkt->tidsmidx].tid<<QLOGIC_IB_I_TID_SHIFT) +
 502                         (pkt->tidsm[pkt->tidsmidx].offset>>2));
 503         } else {
 504                 /* Middle protocol new packet offset */
 505                 hdr->uwords[2] += pkt->payload_size;
 506         }
 507
 508         /* New kdeth checksum */
 509         vcto = le32_to_cpu(hdr->iph.ver_ctxt_tid_offset);
 510         hdr->iph.chksum = cpu_to_le16(QIB_LRH_BTH +
 511                 be16_to_cpu(hdr->lrh[2]) -
 512                 ((vcto>>16)&0xFFFF) - (vcto&0xFFFF) -
 513                 le16_to_cpu(hdr->iph.pkt_flags));
 514
 515         /* Next sequence number in new sdma header */
 516         seqnum.val = be32_to_cpu(hdr->bth[2]);
 517         if (pkt->tiddma)
 518                 seqnum.seq++;
 519         else
 520                 seqnum.pkt++;
 521         hdr->bth[2] = cpu_to_be32(seqnum.val);
 522
 523         /* Init new sdma header. */
 524         qib_user_sdma_init_frag(pkt, pkt->naddr, /* index */
 525                 0, pbclen,              /* offset, len */
 526                 1, 0,                   /* first last desc */
 527                 0, 0,                   /* put page, dma mapped */
 528                 NULL, pbcvaddr,         /* struct page, virt addr */
 529                 pbcdaddr, pbclen);      /* dma addr, dma length */
 530         pkt->index = pkt->naddr;
 531         pkt->payload_size = 0;
 532         pkt->naddr++;
 533         if (pkt->naddr == pkt->addrlimit) {
 534                 ret = -EFAULT;
 535                 goto done;
 536         }
 537
 538         /* Prepare for next fragment in this page */
 539         if (newlen != len) {
 540                 if (dma_mapped) {
 541                         put = 0;
 542                         dma_mapped = 0;
 543                         page = NULL;
 544                         kvaddr = NULL;
 545                 }
 546                 len -= newlen;
 547                 offset += newlen;
 548
 549                 goto next_fragment;
 550         }
 551
 552 done:
 553         return ret;
 554 }
 555
 556 /* we've too many pages in the iovec, coalesce to a single page */
 557 static int qib_user_sdma_coalesce(const struct qib_devdata *dd,
 558                                   struct qib_user_sdma_queue *pq,
 559                                   struct qib_user_sdma_pkt *pkt,
 560                                   const struct iovec *iov,
 561                                   unsigned long niov)
 562 {
 563         int ret = 0;
 564         struct page *page = alloc_page(GFP_KERNEL);
 565         void *mpage_save;
 566         char *mpage;
 567         int i;
 568         int len = 0;
 569
 570         if (!page) {
 571                 ret = -ENOMEM;
 572                 goto done;
 573         }
 574
 575         mpage = kmap(page);
 576         mpage_save = mpage;
 577         for (i = 0; i < niov; i++) {
 578                 int cfur;
 579
 580                 cfur = copy_from_user(mpage,
 581                                       iov[i].iov_base, iov[i].iov_len);
 582                 if (cfur) {
 583                         ret = -EFAULT;
 584                         goto free_unmap;
 585                 }
 586
 587                 mpage += iov[i].iov_len;
 588                 len += iov[i].iov_len;
 589         }
 590
 591         ret = qib_user_sdma_page_to_frags(dd, pq, pkt,
 592                         page, 0, 0, len, mpage_save);
 593         goto done;
 594
 595 free_unmap:
 596         kunmap(page);
 597         __free_page(page);
 598 done:
 599         return ret;
 600 }
 601
 602 /*
 603  * How many pages in this iovec element?
 604  */
 605 static int qib_user_sdma_num_pages(const struct iovec *iov)
 606 {
 607         const unsigned long addr  = (unsigned long) iov->iov_base;
 608         const unsigned long  len  = iov->iov_len;
 609         const unsigned long spage = addr & PAGE_MASK;
 610         const unsigned long epage = (addr + len - 1) & PAGE_MASK;
 611
 612         return 1 + ((epage - spage) >> PAGE_SHIFT);
 613 }
 614
 615 static void qib_user_sdma_free_pkt_frag(struct device *dev,
 616                                         struct qib_user_sdma_queue *pq,
 617                                         struct qib_user_sdma_pkt *pkt,
 618                                         int frag)
 619 {
 620         const int i = frag;
 621
 622         if (pkt->addr[i].page) {
 623                 /* only user data has page */
 624                 if (pkt->addr[i].dma_mapped)
 625                         dma_unmap_page(dev,
 626                                        pkt->addr[i].addr,
 627                                        pkt->addr[i].dma_length,
 628                                        DMA_TO_DEVICE);
 629
 630                 if (pkt->addr[i].kvaddr)
 631                         kunmap(pkt->addr[i].page);
 632
 633                 if (pkt->addr[i].put_page)
 634                         put_page(pkt->addr[i].page);
 635                 else
 636                         __free_page(pkt->addr[i].page);
 637         } else if (pkt->addr[i].kvaddr) {
 638                 /* for headers */
 639                 if (pkt->addr[i].dma_mapped) {
 640                         /* from kmalloc & dma mapped */
 641                         dma_unmap_single(dev,
 642                                        pkt->addr[i].addr,
 643                                        pkt->addr[i].dma_length,
 644                                        DMA_TO_DEVICE);
 645                         kfree(pkt->addr[i].kvaddr);
 646                 } else if (pkt->addr[i].addr) {
 647                         /* free coherent mem from cache... */
 648                         dma_pool_free(pq->header_cache,
 649                               pkt->addr[i].kvaddr, pkt->addr[i].addr);
 650                 } else {
 651                         /* from kmalloc but not dma mapped */
 652                         kfree(pkt->addr[i].kvaddr);
 653                 }
 654         }
 655 }
 656
 657 /* return number of pages pinned... */
 658 static int qib_user_sdma_pin_pages(const struct qib_devdata *dd,
 659                                    struct qib_user_sdma_queue *pq,
 660                                    struct qib_user_sdma_pkt *pkt,
 661                                    unsigned long addr, int tlen, int npages)
 662 {
 663         struct page *pages[8];
 664         int i, j;
 665         int ret = 0;
 666
 667         while (npages) {
 668                 if (npages > 8)
 669                         j = 8;
 670                 else
 671                         j = npages;
 672
 673                 ret = get_user_pages_fast(addr, j, 0, pages);
 674                 if (ret != j) {
 675                         i = 0;
 676                         j = ret;
 677                         ret = -ENOMEM;
 678                         goto free_pages;
 679                 }
 680
 681                 for (i = 0; i < j; i++) {
 682                         /* map the pages... */
 683                         unsigned long fofs = addr & ~PAGE_MASK;
 684                         int flen = ((fofs + tlen) > PAGE_SIZE) ?
 685                                 (PAGE_SIZE - fofs) : tlen;
 686
 687                         ret = qib_user_sdma_page_to_frags(dd, pq, pkt,
 688                                 pages[i], 1, fofs, flen, NULL);
 689                         if (ret < 0) {
 690                                 /* current page has beed taken
 691                                  * care of inside above call.
 692                                  */
 693                                 i++;
 694                                 goto free_pages;
 695                         }
 696
 697                         addr += flen;
 698                         tlen -= flen;
 699                 }
 700
 701                 npages -= j;
 702         }
 703
 704         goto done;
 705
 706         /* if error, return all pages not managed by pkt */
 707 free_pages:
 708         while (i < j)
 709                 put_page(pages[i++]);
 710
 711 done:
 712         return ret;
 713 }
 714
 715 static int qib_user_sdma_pin_pkt(const struct qib_devdata *dd,
 716                                  struct qib_user_sdma_queue *pq,
 717                                  struct qib_user_sdma_pkt *pkt,
 718                                  const struct iovec *iov,
 719                                  unsigned long niov)
 720 {
 721         int ret = 0;
 722         unsigned long idx;
 723
 724         for (idx = 0; idx < niov; idx++) {
 725                 const int npages = qib_user_sdma_num_pages(iov + idx);
 726                 const unsigned long addr = (unsigned long) iov[idx].iov_base;
 727
 728                 ret = qib_user_sdma_pin_pages(dd, pq, pkt, addr,
 729                                               iov[idx].iov_len, npages);
 730                 if (ret < 0)
 731                         goto free_pkt;
 732         }
 733
 734         goto done;
 735
 736 free_pkt:
 737         /* we need to ignore the first entry here */
 738         for (idx = 1; idx < pkt->naddr; idx++)
 739                 qib_user_sdma_free_pkt_frag(&dd->pcidev->dev, pq, pkt, idx);
 740
 741         /* need to dma unmap the first entry, this is to restore to
 742          * the original state so that caller can free the memory in
 743          * error condition. Caller does not know if dma mapped or not*/
 744         if (pkt->addr[0].dma_mapped) {
 745                 dma_unmap_single(&dd->pcidev->dev,
 746                        pkt->addr[0].addr,
 747                        pkt->addr[0].dma_length,
 748                        DMA_TO_DEVICE);
 749                 pkt->addr[0].addr = 0;
 750                 pkt->addr[0].dma_mapped = 0;
 751         }
 752
 753 done:
 754         return ret;
 755 }
 756
 757 static int qib_user_sdma_init_payload(const struct qib_devdata *dd,
 758                                       struct qib_user_sdma_queue *pq,
 759                                       struct qib_user_sdma_pkt *pkt,
 760                                       const struct iovec *iov,
 761                                       unsigned long niov, int npages)
 762 {
 763         int ret = 0;
 764
 765         if (pkt->frag_size == pkt->bytes_togo &&
 766                         npages >= ARRAY_SIZE(pkt->addr))
 767                 ret = qib_user_sdma_coalesce(dd, pq, pkt, iov, niov);
 768         else
 769                 ret = qib_user_sdma_pin_pkt(dd, pq, pkt, iov, niov);
 770
 771         return ret;
 772 }
 773
 774 /* free a packet list -- return counter value of last packet */
 775 static void qib_user_sdma_free_pkt_list(struct device *dev,
 776                                         struct qib_user_sdma_queue *pq,
 777                                         struct list_head *list)
 778 {
 779         struct qib_user_sdma_pkt *pkt, *pkt_next;
 780
 781         list_for_each_entry_safe(pkt, pkt_next, list, list) {
 782                 int i;
 783
 784                 for (i = 0; i < pkt->naddr; i++)
 785                         qib_user_sdma_free_pkt_frag(dev, pq, pkt, i);
 786
 787                 if (pkt->largepkt)
 788                         kfree(pkt);
 789                 else
 790                         kmem_cache_free(pq->pkt_slab, pkt);
 791         }
 792         INIT_LIST_HEAD(list);
 793 }
 794
 795 /*
 796  * copy headers, coalesce etc -- pq->lock must be held
 797  *
 798  * we queue all the packets to list, returning the
 799  * number of bytes total.  list must be empty initially,
 800  * as, if there is an error we clean it...
 801  */
 802 static int qib_user_sdma_queue_pkts(const struct qib_devdata *dd,
 803                                     struct qib_pportdata *ppd,
 804                                     struct qib_user_sdma_queue *pq,
 805                                     const struct iovec *iov,
 806                                     unsigned long niov,
 807                                     struct list_head *list,
 808                                     int *maxpkts, int *ndesc)
 809 {
 810         unsigned long idx = 0;
 811         int ret = 0;
 812         int npkts = 0;
 813         __le32 *pbc;
 814         dma_addr_t dma_addr;
 815         struct qib_user_sdma_pkt *pkt = NULL;
 816         size_t len;
 817         size_t nw;
 818         u32 counter = pq->counter;
 819         u16 frag_size;
 820
 821         while (idx < niov && npkts < *maxpkts) {
 822                 const unsigned long addr = (unsigned long) iov[idx].iov_base;
 823                 const unsigned long idx_save = idx;
 824                 unsigned pktnw;
 825                 unsigned pktnwc;
 826                 int nfrags = 0;
 827                 int npages = 0;
 828                 int bytes_togo = 0;
 829                 int tiddma = 0;
 830                 int cfur;
 831
 832                 len = iov[idx].iov_len;
 833                 nw = len >> 2;
 834
 835                 if (len < QIB_USER_SDMA_MIN_HEADER_LENGTH ||
 836                     len > PAGE_SIZE || len & 3 || addr & 3) {
 837                         ret = -EINVAL;
 838                         goto free_list;
 839                 }
 840
 841                 pbc = qib_user_sdma_alloc_header(pq, len, &dma_addr);
 842                 if (!pbc) {
 843                         ret = -ENOMEM;
 844                         goto free_list;
 845                 }
 846
 847                 cfur = copy_from_user(pbc, iov[idx].iov_base, len);
 848                 if (cfur) {
 849                         ret = -EFAULT;
 850                         goto free_pbc;
 851                 }
 852
 853                 /*
 854                  * This assignment is a bit strange.  it's because the
 855                  * the pbc counts the number of 32 bit words in the full
 856                  * packet _except_ the first word of the pbc itself...
 857                  */
 858                 pktnwc = nw - 1;
 859
 860                 /*
 861                  * pktnw computation yields the number of 32 bit words
 862                  * that the caller has indicated in the PBC.  note that
 863                  * this is one less than the total number of words that
 864                  * goes to the send DMA engine as the first 32 bit word
 865                  * of the PBC itself is not counted.  Armed with this count,
 866                  * we can verify that the packet is consistent with the
 867                  * iovec lengths.
 868                  */
 869                 pktnw = le32_to_cpu(*pbc) & 0xFFFF;
 870                 if (pktnw < pktnwc) {
 871                         ret = -EINVAL;
 872                         goto free_pbc;
 873                 }
 874
 875                 idx++;
 876                 while (pktnwc < pktnw && idx < niov) {
 877                         const size_t slen = iov[idx].iov_len;
 878                         const unsigned long faddr =
 879                                 (unsigned long) iov[idx].iov_base;
 880
 881                         if (slen & 3 || faddr & 3 || !slen) {
 882                                 ret = -EINVAL;
 883                                 goto free_pbc;
 884                         }
 885
 886                         npages += qib_user_sdma_num_pages(&iov[idx]);
 887
 888                         bytes_togo += slen;
 889                         pktnwc += slen >> 2;
 890                         idx++;
 891                         nfrags++;
 892                 }
 893
 894                 if (pktnwc != pktnw) {
 895                         ret = -EINVAL;
 896                         goto free_pbc;
 897                 }
 898
 899                 frag_size = ((le32_to_cpu(*pbc))>>16) & 0xFFFF;
 900                 if (((frag_size ? frag_size : bytes_togo) + len) >
 901                                                 ppd->ibmaxlen) {
 902                         ret = -EINVAL;
 903                         goto free_pbc;
 904                 }
 905
 906                 if (frag_size) {
 907                         int pktsize, tidsmsize, n;
 908
 909                         n = npages*((2*PAGE_SIZE/frag_size)+1);
 910                         pktsize = sizeof(*pkt) + sizeof(pkt->addr[0])*n;
 911
 912                         /*
 913                          * Determine if this is tid-sdma or just sdma.
 914                          */
 915                         tiddma = (((le32_to_cpu(pbc[7])>>
 916                                 QLOGIC_IB_I_TID_SHIFT)&
 917                                 QLOGIC_IB_I_TID_MASK) !=
 918                                 QLOGIC_IB_I_TID_MASK);
 919
 920                         if (tiddma)
 921                                 tidsmsize = iov[idx].iov_len;
 922                         else
 923                                 tidsmsize = 0;
 924
 925                         pkt = kmalloc(pktsize+tidsmsize, GFP_KERNEL);
 926                         if (!pkt) {
 927                                 ret = -ENOMEM;
 928                                 goto free_pbc;
 929                         }
 930                         pkt->largepkt = 1;
 931                         pkt->frag_size = frag_size;
 932                         pkt->addrlimit = n + ARRAY_SIZE(pkt->addr);
 933
 934                         if (tiddma) {
 935                                 char *tidsm = (char *)pkt + pktsize;
 936
 937                                 cfur = copy_from_user(tidsm,
 938                                         iov[idx].iov_base, tidsmsize);
 939                                 if (cfur) {
 940                                         ret = -EFAULT;
 941                                         goto free_pkt;
 942                                 }
 943                                 pkt->tidsm =
 944                                         (struct qib_tid_session_member *)tidsm;
 945                                 pkt->tidsmcount = tidsmsize/
 946                                         sizeof(struct qib_tid_session_member);
 947                                 pkt->tidsmidx = 0;
 948                                 idx++;
 949                         }
 950
 951                         /*
 952                          * pbc 'fill1' field is borrowed to pass frag size,
 953                          * we need to clear it after picking frag size, the
 954                          * hardware requires this field to be zero.
 955                          */
 956                         *pbc = cpu_to_le32(le32_to_cpu(*pbc) & 0x0000FFFF);
 957                 } else {
 958                         pkt = kmem_cache_alloc(pq->pkt_slab, GFP_KERNEL);
 959                         if (!pkt) {
 960                                 ret = -ENOMEM;
 961                                 goto free_pbc;
 962                         }
 963                         pkt->largepkt = 0;
 964                         pkt->frag_size = bytes_togo;
 965                         pkt->addrlimit = ARRAY_SIZE(pkt->addr);
 966                 }
 967                 pkt->bytes_togo = bytes_togo;
 968                 pkt->payload_size = 0;
 969                 pkt->counter = counter;
 970                 pkt->tiddma = tiddma;
 971
 972                 /* setup the first header */
 973                 qib_user_sdma_init_frag(pkt, 0, /* index */
 974                         0, len,         /* offset, len */
 975                         1, 0,           /* first last desc */
 976                         0, 0,           /* put page, dma mapped */
 977                         NULL, pbc,      /* struct page, virt addr */
 978                         dma_addr, len); /* dma addr, dma length */
 979                 pkt->index = 0;
 980                 pkt->naddr = 1;
 981
 982                 if (nfrags) {
 983                         ret = qib_user_sdma_init_payload(dd, pq, pkt,
 984                                                          iov + idx_save + 1,
 985                                                          nfrags, npages);
 986                         if (ret < 0)
 987                                 goto free_pkt;
 988                 } else {
 989                         /* since there is no payload, mark the
 990                          * header as the last desc. */
 991                         pkt->addr[0].last_desc = 1;
 992
 993                         if (dma_addr == 0) {
 994                                 /*
 995                                  * the header is not dma mapped yet.
 996                                  * it should be from kmalloc.
 997                                  */
 998                                 dma_addr = dma_map_single(&dd->pcidev->dev,
 999                                         pbc, len, DMA_TO_DEVICE);
1000                                 if (dma_mapping_error(&dd->pcidev->dev,
1001                                                                 dma_addr)) {
1002                                         ret = -ENOMEM;
1003                                         goto free_pkt;
1004                                 }
1005                                 pkt->addr[0].addr = dma_addr;
1006                                 pkt->addr[0].dma_mapped = 1;
1007                         }
1008                 }
1009
1010                 counter++;
1011                 npkts++;
1012                 pkt->pq = pq;
1013                 pkt->index = 0; /* reset index for push on hw */
1014                 *ndesc += pkt->naddr;
1015
1016                 list_add_tail(&pkt->list, list);
1017         }
1018
1019         *maxpkts = npkts;
1020         ret = idx;
1021         goto done;
1022
1023 free_pkt:
1024         if (pkt->largepkt)
1025                 kfree(pkt);
1026         else
1027                 kmem_cache_free(pq->pkt_slab, pkt);
1028 free_pbc:
1029         if (dma_addr)
1030                 dma_pool_free(pq->header_cache, pbc, dma_addr);
1031         else
1032                 kfree(pbc);
1033 free_list:
1034         qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, list);
1035 done:
1036         return ret;
1037 }
1038
1039 static void qib_user_sdma_set_complete_counter(struct qib_user_sdma_queue *pq,
1040                                                u32 c)
1041 {
1042         pq->sent_counter = c;
1043 }
1044
1045 /* try to clean out queue -- needs pq->lock */
1046 static int qib_user_sdma_queue_clean(struct qib_pportdata *ppd,
1047                                      struct qib_user_sdma_queue *pq)
1048 {
1049         struct qib_devdata *dd = ppd->dd;
1050         struct list_head free_list;
1051         struct qib_user_sdma_pkt *pkt;
1052         struct qib_user_sdma_pkt *pkt_prev;
1053         unsigned long flags;
1054         int ret = 0;
1055
1056         if (!pq->num_sending)
1057                 return 0;
1058
1059         INIT_LIST_HEAD(&free_list);
1060
1061         /*
1062          * We need this spin lock here because interrupt handler
1063          * might modify this list in qib_user_sdma_send_desc(), also
1064          * we can not get interrupted, otherwise it is a deadlock.
1065          */
1066         spin_lock_irqsave(&pq->sent_lock, flags);
1067         list_for_each_entry_safe(pkt, pkt_prev, &pq->sent, list) {
1068                 s64 descd = ppd->sdma_descq_removed - pkt->added;
1069
1070                 if (descd < 0)
1071                         break;
1072
1073                 list_move_tail(&pkt->list, &free_list);
1074
1075                 /* one more packet cleaned */
1076                 ret++;
1077                 pq->num_sending--;
1078         }
1079         spin_unlock_irqrestore(&pq->sent_lock, flags);
1080
1081         if (!list_empty(&free_list)) {
1082                 u32 counter;
1083
1084                 pkt = list_entry(free_list.prev,
1085                                  struct qib_user_sdma_pkt, list);
1086                 counter = pkt->counter;
1087
1088                 qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
1089                 qib_user_sdma_set_complete_counter(pq, counter);
1090         }
1091
1092         return ret;
1093 }
1094
1095 void qib_user_sdma_queue_destroy(struct qib_user_sdma_queue *pq)
1096 {
1097         if (!pq)
1098                 return;
1099
1100         pq->sdma_rb_node->refcount--;
1101         if (pq->sdma_rb_node->refcount == 0) {
1102                 rb_erase(&pq->sdma_rb_node->node, &qib_user_sdma_rb_root);
1103                 kfree(pq->sdma_rb_node);
1104         }
1105         dma_pool_destroy(pq->header_cache);
1106         kmem_cache_destroy(pq->pkt_slab);
1107         kfree(pq);
1108 }
1109
1110 /* clean descriptor queue, returns > 0 if some elements cleaned */
1111 static int qib_user_sdma_hwqueue_clean(struct qib_pportdata *ppd)
1112 {
1113         int ret;
1114         unsigned long flags;
1115
1116         spin_lock_irqsave(&ppd->sdma_lock, flags);
1117         ret = qib_sdma_make_progress(ppd);
1118         spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1119
1120         return ret;
1121 }
1122
1123 /* we're in close, drain packets so that we can cleanup successfully... */
1124 void qib_user_sdma_queue_drain(struct qib_pportdata *ppd,
1125                                struct qib_user_sdma_queue *pq)
1126 {
1127         struct qib_devdata *dd = ppd->dd;
1128         unsigned long flags;
1129         int i;
1130
1131         if (!pq)
1132                 return;
1133
1134         for (i = 0; i < QIB_USER_SDMA_DRAIN_TIMEOUT; i++) {
1135                 mutex_lock(&pq->lock);
1136                 if (!pq->num_pending && !pq->num_sending) {
1137                         mutex_unlock(&pq->lock);
1138                         break;
1139                 }
1140                 qib_user_sdma_hwqueue_clean(ppd);
1141                 qib_user_sdma_queue_clean(ppd, pq);
1142                 mutex_unlock(&pq->lock);
1143                 msleep(20);
1144         }
1145
1146         if (pq->num_pending || pq->num_sending) {
1147                 struct qib_user_sdma_pkt *pkt;
1148                 struct qib_user_sdma_pkt *pkt_prev;
1149                 struct list_head free_list;
1150
1151                 mutex_lock(&pq->lock);
1152                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1153                 /*
1154                  * Since we hold sdma_lock, it is safe without sent_lock.
1155                  */
1156                 if (pq->num_pending) {
1157                         list_for_each_entry_safe(pkt, pkt_prev,
1158                                         &ppd->sdma_userpending, list) {
1159                                 if (pkt->pq == pq) {
1160                                         list_move_tail(&pkt->list, &pq->sent);
1161                                         pq->num_pending--;
1162                                         pq->num_sending++;
1163                                 }
1164                         }
1165                 }
1166                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1167
1168                 qib_dev_err(dd, "user sdma lists not empty: forcing!\n");
1169                 INIT_LIST_HEAD(&free_list);
1170                 list_splice_init(&pq->sent, &free_list);
1171                 pq->num_sending = 0;
1172                 qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
1173                 mutex_unlock(&pq->lock);
1174         }
1175 }
1176
1177 static inline __le64 qib_sdma_make_desc0(u8 gen,
1178                                          u64 addr, u64 dwlen, u64 dwoffset)
1179 {
1180         return cpu_to_le64(/* SDmaPhyAddr[31:0] */
1181                            ((addr & 0xfffffffcULL) << 32) |
1182                            /* SDmaGeneration[1:0] */
1183                            ((gen & 3ULL) << 30) |
1184                            /* SDmaDwordCount[10:0] */
1185                            ((dwlen & 0x7ffULL) << 16) |
1186                            /* SDmaBufOffset[12:2] */
1187                            (dwoffset & 0x7ffULL));
1188 }
1189
1190 static inline __le64 qib_sdma_make_first_desc0(__le64 descq)
1191 {
1192         return descq | cpu_to_le64(1ULL << 12);
1193 }
1194
1195 static inline __le64 qib_sdma_make_last_desc0(__le64 descq)
1196 {
1197                                               /* last */  /* dma head */
1198         return descq | cpu_to_le64(1ULL << 11 | 1ULL << 13);
1199 }
1200
1201 static inline __le64 qib_sdma_make_desc1(u64 addr)
1202 {
1203         /* SDmaPhyAddr[47:32] */
1204         return cpu_to_le64(addr >> 32);
1205 }
1206
1207 static void qib_user_sdma_send_frag(struct qib_pportdata *ppd,
1208                                     struct qib_user_sdma_pkt *pkt, int idx,
1209                                     unsigned ofs, u16 tail, u8 gen)
1210 {
1211         const u64 addr = (u64) pkt->addr[idx].addr +
1212                 (u64) pkt->addr[idx].offset;
1213         const u64 dwlen = (u64) pkt->addr[idx].length / 4;
1214         __le64 *descqp;
1215         __le64 descq0;
1216
1217         descqp = &ppd->sdma_descq[tail].qw[0];
1218
1219         descq0 = qib_sdma_make_desc0(gen, addr, dwlen, ofs);
1220         if (pkt->addr[idx].first_desc)
1221                 descq0 = qib_sdma_make_first_desc0(descq0);
1222         if (pkt->addr[idx].last_desc) {
1223                 descq0 = qib_sdma_make_last_desc0(descq0);
1224                 if (ppd->sdma_intrequest) {
1225                         descq0 |= cpu_to_le64(1ULL << 15);
1226                         ppd->sdma_intrequest = 0;
1227                 }
1228         }
1229
1230         descqp[0] = descq0;
1231         descqp[1] = qib_sdma_make_desc1(addr);
1232 }
1233
1234 void qib_user_sdma_send_desc(struct qib_pportdata *ppd,
1235                                 struct list_head *pktlist)
1236 {
1237         struct qib_devdata *dd = ppd->dd;
1238         u16 nfree, nsent;
1239         u16 tail, tail_c;
1240         u8 gen, gen_c;
1241
1242         nfree = qib_sdma_descq_freecnt(ppd);
1243         if (!nfree)
1244                 return;
1245
1246 retry:
1247         nsent = 0;
1248         tail_c = tail = ppd->sdma_descq_tail;
1249         gen_c = gen = ppd->sdma_generation;
1250         while (!list_empty(pktlist)) {
1251                 struct qib_user_sdma_pkt *pkt =
1252                         list_entry(pktlist->next, struct qib_user_sdma_pkt,
1253                                    list);
1254                 int i, j, c = 0;
1255                 unsigned ofs = 0;
1256                 u16 dtail = tail;
1257
1258                 for (i = pkt->index; i < pkt->naddr && nfree; i++) {
1259                         qib_user_sdma_send_frag(ppd, pkt, i, ofs, tail, gen);
1260                         ofs += pkt->addr[i].length >> 2;
1261
1262                         if (++tail == ppd->sdma_descq_cnt) {
1263                                 tail = 0;
1264                                 ++gen;
1265                                 ppd->sdma_intrequest = 1;
1266                         } else if (tail == (ppd->sdma_descq_cnt>>1)) {
1267                                 ppd->sdma_intrequest = 1;
1268                         }
1269                         nfree--;
1270                         if (pkt->addr[i].last_desc == 0)
1271                                 continue;
1272
1273                         /*
1274                          * If the packet is >= 2KB mtu equivalent, we
1275                          * have to use the large buffers, and have to
1276                          * mark each descriptor as part of a large
1277                          * buffer packet.
1278                          */
1279                         if (ofs > dd->piosize2kmax_dwords) {
1280                                 for (j = pkt->index; j <= i; j++) {
1281                                         ppd->sdma_descq[dtail].qw[0] |=
1282                                                 cpu_to_le64(1ULL << 14);
1283                                         if (++dtail == ppd->sdma_descq_cnt)
1284                                                 dtail = 0;
1285                                 }
1286                         }
1287                         c += i + 1 - pkt->index;
1288                         pkt->index = i + 1; /* index for next first */
1289                         tail_c = dtail = tail;
1290                         gen_c = gen;
1291                         ofs = 0;  /* reset for next packet */
1292                 }
1293
1294                 ppd->sdma_descq_added += c;
1295                 nsent += c;
1296                 if (pkt->index == pkt->naddr) {
1297                         pkt->added = ppd->sdma_descq_added;
1298                         pkt->pq->added = pkt->added;
1299                         pkt->pq->num_pending--;
1300                         spin_lock(&pkt->pq->sent_lock);
1301                         pkt->pq->num_sending++;
1302                         list_move_tail(&pkt->list, &pkt->pq->sent);
1303                         spin_unlock(&pkt->pq->sent_lock);
1304                 }
1305                 if (!nfree || (nsent<<2) > ppd->sdma_descq_cnt)
1306                         break;
1307         }
1308
1309         /* advance the tail on the chip if necessary */
1310         if (ppd->sdma_descq_tail != tail_c) {
1311                 ppd->sdma_generation = gen_c;
1312                 dd->f_sdma_update_tail(ppd, tail_c);
1313         }
1314
1315         if (nfree && !list_empty(pktlist))
1316                 goto retry;
1317 }
1318
1319 /* pq->lock must be held, get packets on the wire... */
1320 static int qib_user_sdma_push_pkts(struct qib_pportdata *ppd,
1321                                  struct qib_user_sdma_queue *pq,
1322                                  struct list_head *pktlist, int count)
1323 {
1324         unsigned long flags;
1325
1326         if (unlikely(!(ppd->lflags & QIBL_LINKACTIVE)))
1327                 return -ECOMM;
1328
1329         /* non-blocking mode */
1330         if (pq->sdma_rb_node->refcount > 1) {
1331                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1332                 if (unlikely(!__qib_sdma_running(ppd))) {
1333                         spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1334                         return -ECOMM;
1335                 }
1336                 pq->num_pending += count;
1337                 list_splice_tail_init(pktlist, &ppd->sdma_userpending);
1338                 qib_user_sdma_send_desc(ppd, &ppd->sdma_userpending);
1339                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1340                 return 0;
1341         }
1342
1343         /* In this case, descriptors from this process are not
1344          * linked to ppd pending queue, interrupt handler
1345          * won't update this process, it is OK to directly
1346          * modify without sdma lock.
1347          */
1348
1349
1350         pq->num_pending += count;
1351         /*
1352          * Blocking mode for single rail process, we must
1353          * release/regain sdma_lock to give other process
1354          * chance to make progress. This is important for
1355          * performance.
1356          */
1357         do {
1358                 spin_lock_irqsave(&ppd->sdma_lock, flags);
1359                 if (unlikely(!__qib_sdma_running(ppd))) {
1360                         spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1361                         return -ECOMM;
1362                 }
1363                 qib_user_sdma_send_desc(ppd, pktlist);
1364                 if (!list_empty(pktlist))
1365                         qib_sdma_make_progress(ppd);
1366                 spin_unlock_irqrestore(&ppd->sdma_lock, flags);
1367         } while (!list_empty(pktlist));
1368
1369         return 0;
1370 }
1371
1372 int qib_user_sdma_writev(struct qib_ctxtdata *rcd,
1373                          struct qib_user_sdma_queue *pq,
1374                          const struct iovec *iov,
1375                          unsigned long dim)
1376 {
1377         struct qib_devdata *dd = rcd->dd;
1378         struct qib_pportdata *ppd = rcd->ppd;
1379         int ret = 0;
1380         struct list_head list;
1381         int npkts = 0;
1382
1383         INIT_LIST_HEAD(&list);
1384
1385         mutex_lock(&pq->lock);
1386
1387         /* why not -ECOMM like qib_user_sdma_push_pkts() below? */
1388         if (!qib_sdma_running(ppd))
1389                 goto done_unlock;
1390
1391         /* if I have packets not complete yet */
1392         if (pq->added > ppd->sdma_descq_removed)
1393                 qib_user_sdma_hwqueue_clean(ppd);
1394         /* if I have complete packets to be freed */
1395         if (pq->num_sending)
1396                 qib_user_sdma_queue_clean(ppd, pq);
1397
1398         while (dim) {
1399                 int mxp = 1;
1400                 int ndesc = 0;
1401
1402                 ret = qib_user_sdma_queue_pkts(dd, ppd, pq,
1403                                 iov, dim, &list, &mxp, &ndesc);
1404                 if (ret < 0)
1405                         goto done_unlock;
1406                 else {
1407                         dim -= ret;
1408                         iov += ret;
1409                 }
1410
1411                 /* force packets onto the sdma hw queue... */
1412                 if (!list_empty(&list)) {
1413                         /*
1414                          * Lazily clean hw queue.
1415                          */
1416                         if (qib_sdma_descq_freecnt(ppd) < ndesc) {
1417                                 qib_user_sdma_hwqueue_clean(ppd);
1418                                 if (pq->num_sending)
1419                                         qib_user_sdma_queue_clean(ppd, pq);
1420                         }
1421
1422                         ret = qib_user_sdma_push_pkts(ppd, pq, &list, mxp);
1423                         if (ret < 0)
1424                                 goto done_unlock;
1425                         else {
1426                                 npkts += mxp;
1427                                 pq->counter += mxp;
1428                         }
1429                 }
1430         }
1431
1432 done_unlock:
1433         if (!list_empty(&list))
1434                 qib_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &list);
1435         mutex_unlock(&pq->lock);
1436
1437         return (ret < 0) ? ret : npkts;
1438 }
1439
1440 int qib_user_sdma_make_progress(struct qib_pportdata *ppd,
1441                                 struct qib_user_sdma_queue *pq)
1442 {
1443         int ret = 0;
1444
1445         mutex_lock(&pq->lock);
1446         qib_user_sdma_hwqueue_clean(ppd);
1447         ret = qib_user_sdma_queue_clean(ppd, pq);
1448         mutex_unlock(&pq->lock);
1449
1450         return ret;
1451 }
1452
1453 u32 qib_user_sdma_complete_counter(const struct qib_user_sdma_queue *pq)
1454 {
1455         return pq ? pq->sent_counter : 0;
1456 }
1457
1458 u32 qib_user_sdma_inflight_counter(struct qib_user_sdma_queue *pq)
1459 {
1460         return pq ? pq->counter : 0;
1461 }