drivers/misc/mic/scif/scif_nodeqp.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2014 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * Intel SCIF driver.
  16  *
  17  */
  18 #include "../bus/scif_bus.h"
  19 #include "scif_peer_bus.h"
  20 #include "scif_main.h"
  21 #include "scif_nodeqp.h"
  22 #include "scif_map.h"
  23
  24 /*
  25  ************************************************************************
  26  * SCIF node Queue Pair (QP) setup flow:
  27  *
  28  * 1) SCIF driver gets probed with a scif_hw_dev via the scif_hw_bus
  29  * 2) scif_setup_qp(..) allocates the local qp and calls
  30  *      scif_setup_qp_connect(..) which allocates and maps the local
  31  *      buffer for the inbound QP
  32  * 3) The local node updates the device page with the DMA address of the QP
  33  * 4) A delayed work is scheduled (qp_dwork) which periodically reads if
  34  *      the peer node has updated its QP DMA address
  35  * 5) Once a valid non zero address is found in the QP DMA address field
  36  *      in the device page, the local node maps the remote node's QP,
  37  *      updates its outbound QP and sends a SCIF_INIT message to the peer
  38  * 6) The SCIF_INIT message is received by the peer node QP interrupt bottom
  39  *      half handler by calling scif_init(..)
  40  * 7) scif_init(..) registers a new SCIF peer node by calling
  41  *      scif_peer_register_device(..) which signifies the addition of a new
  42  *      SCIF node
  43  * 8) On the mgmt node, P2P network setup/teardown is initiated if all the
  44  *      remote nodes are online via scif_p2p_setup(..)
  45  * 9) For P2P setup, the host maps the remote nodes' aperture and memory
  46  *      bars and sends a SCIF_NODE_ADD message to both nodes
  47  * 10) As part of scif_nodeadd, both nodes set up their local inbound
  48  *      QPs and send a SCIF_NODE_ADD_ACK to the mgmt node
  49  * 11) As part of scif_node_add_ack(..) the mgmt node forwards the
  50  *      SCIF_NODE_ADD_ACK to the remote nodes
  51  * 12) As part of scif_node_add_ack(..) the remote nodes update their
  52  *      outbound QPs, make sure they can access memory on the remote node
  53  *      and then add a new SCIF peer node by calling
  54  *      scif_peer_register_device(..) which signifies the addition of a new
  55  *      SCIF node.
  56  * 13) The SCIF network is now established across all nodes.
  57  *
  58  ************************************************************************
  59  * SCIF node QP teardown flow (initiated by non mgmt node):
  60  *
  61  * 1) SCIF driver gets a remove callback with a scif_hw_dev via the scif_hw_bus
  62  * 2) The device page QP DMA address field is updated with 0x0
  63  * 3) A non mgmt node now cleans up all local data structures and sends a
  64  *      SCIF_EXIT message to the peer and waits for a SCIF_EXIT_ACK
  65  * 4) As part of scif_exit(..) handling scif_disconnect_node(..) is called
  66  * 5) scif_disconnect_node(..) sends a SCIF_NODE_REMOVE message to all the
  67  *      peers and waits for a SCIF_NODE_REMOVE_ACK
  68  * 6) As part of scif_node_remove(..) a remote node unregisters the peer
  69  *      node from the SCIF network and sends a SCIF_NODE_REMOVE_ACK
  70  * 7) When the mgmt node has received all the SCIF_NODE_REMOVE_ACKs
  71  *      it sends itself a node remove message whose handling cleans up local
  72  *      data structures and unregisters the peer node from the SCIF network
  73  * 8) The mgmt node sends a SCIF_EXIT_ACK
  74  * 9) Upon receipt of the SCIF_EXIT_ACK the node initiating the teardown
  75  *      completes the SCIF remove routine
  76  * 10) The SCIF network is now torn down for the node initiating the
  77  *      teardown sequence
  78  *
  79  ************************************************************************
  80  * SCIF node QP teardown flow (initiated by mgmt node):
  81  *
  82  * 1) SCIF driver gets a remove callback with a scif_hw_dev via the scif_hw_bus
  83  * 2) The device page QP DMA address field is updated with 0x0
  84  * 3) The mgmt node calls scif_disconnect_node(..)
  85  * 4) scif_disconnect_node(..) sends a SCIF_NODE_REMOVE message to all the peers
  86  *      and waits for a SCIF_NODE_REMOVE_ACK
  87  * 5) As part of scif_node_remove(..) a remote node unregisters the peer
  88  *      node from the SCIF network and sends a SCIF_NODE_REMOVE_ACK
  89  * 6) When the mgmt node has received all the SCIF_NODE_REMOVE_ACKs
  90  *      it unregisters the peer node from the SCIF network
  91  * 7) The mgmt node sends a SCIF_EXIT message and waits for a SCIF_EXIT_ACK.
  92  * 8) A non mgmt node upon receipt of a SCIF_EXIT message calls scif_stop(..)
  93  *      which would clean up local data structures for all SCIF nodes and
  94  *      then send a SCIF_EXIT_ACK back to the mgmt node
  95  * 9) Upon receipt of the SCIF_EXIT_ACK the the mgmt node sends itself a node
  96  *      remove message whose handling cleans up local data structures and
  97  *      destroys any P2P mappings.
  98  * 10) The SCIF hardware device for which a remove callback was received is now
  99  *      disconnected from the SCIF network.
 100  */
 101 /*
 102  * Initializes "local" data structures for the QP. Allocates the QP
 103  * ring buffer (rb) and initializes the "in bound" queue.
 104  */
 105 int scif_setup_qp_connect(struct scif_qp *qp, dma_addr_t *qp_offset,
 106                           int local_size, struct scif_dev *scifdev)
 107 {
 108         void *local_q = NULL;
 109         int err = 0;
 110         u32 tmp_rd = 0;
 111
 112         spin_lock_init(&qp->send_lock);
 113         spin_lock_init(&qp->recv_lock);
 114
 115         local_q = kzalloc(local_size, GFP_KERNEL);
 116         if (!local_q) {
 117                 err = -ENOMEM;
 118                 return err;
 119         }
 120         err = scif_map_single(&qp->local_buf, local_q, scifdev, local_size);
 121         if (err)
 122                 goto kfree;
 123         /*
 124          * To setup the inbound_q, the buffer lives locally, the read pointer
 125          * is remote and the write pointer is local.
 126          */
 127         scif_rb_init(&qp->inbound_q,
 128                      &tmp_rd,
 129                      &qp->local_write,
 130                      local_q, get_count_order(local_size));
 131         /*
 132          * The read pointer is NULL initially and it is unsafe to use the ring
 133          * buffer til this changes!
 134          */
 135         qp->inbound_q.read_ptr = NULL;
 136         err = scif_map_single(qp_offset, qp,
 137                               scifdev, sizeof(struct scif_qp));
 138         if (err)
 139                 goto unmap;
 140         qp->local_qp = *qp_offset;
 141         return err;
 142 unmap:
 143         scif_unmap_single(qp->local_buf, scifdev, local_size);
 144         qp->local_buf = 0;
 145 kfree:
 146         kfree(local_q);
 147         return err;
 148 }
 149
 150 /* When the other side has already done it's allocation, this is called */
 151 int scif_setup_qp_accept(struct scif_qp *qp, dma_addr_t *qp_offset,
 152                          dma_addr_t phys, int local_size,
 153                          struct scif_dev *scifdev)
 154 {
 155         void *local_q;
 156         void *remote_q;
 157         struct scif_qp *remote_qp;
 158         int remote_size;
 159         int err = 0;
 160
 161         spin_lock_init(&qp->send_lock);
 162         spin_lock_init(&qp->recv_lock);
 163         /* Start by figuring out where we need to point */
 164         remote_qp = scif_ioremap(phys, sizeof(struct scif_qp), scifdev);
 165         if (!remote_qp)
 166                 return -EIO;
 167         qp->remote_qp = remote_qp;
 168         if (qp->remote_qp->magic != SCIFEP_MAGIC) {
 169                 err = -EIO;
 170                 goto iounmap;
 171         }
 172         qp->remote_buf = remote_qp->local_buf;
 173         remote_size = qp->remote_qp->inbound_q.size;
 174         remote_q = scif_ioremap(qp->remote_buf, remote_size, scifdev);
 175         if (!remote_q) {
 176                 err = -EIO;
 177                 goto iounmap;
 178         }
 179         qp->remote_qp->local_write = 0;
 180         /*
 181          * To setup the outbound_q, the buffer lives in remote memory,
 182          * the read pointer is local, the write pointer is remote
 183          */
 184         scif_rb_init(&qp->outbound_q,
 185                      &qp->local_read,
 186                      &qp->remote_qp->local_write,
 187                      remote_q,
 188                      get_count_order(remote_size));
 189         local_q = kzalloc(local_size, GFP_KERNEL);
 190         if (!local_q) {
 191                 err = -ENOMEM;
 192                 goto iounmap_1;
 193         }
 194         err = scif_map_single(&qp->local_buf, local_q, scifdev, local_size);
 195         if (err)
 196                 goto kfree;
 197         qp->remote_qp->local_read = 0;
 198         /*
 199          * To setup the inbound_q, the buffer lives locally, the read pointer
 200          * is remote and the write pointer is local
 201          */
 202         scif_rb_init(&qp->inbound_q,
 203                      &qp->remote_qp->local_read,
 204                      &qp->local_write,
 205                      local_q, get_count_order(local_size));
 206         err = scif_map_single(qp_offset, qp, scifdev,
 207                               sizeof(struct scif_qp));
 208         if (err)
 209                 goto unmap;
 210         qp->local_qp = *qp_offset;
 211         return err;
 212 unmap:
 213         scif_unmap_single(qp->local_buf, scifdev, local_size);
 214         qp->local_buf = 0;
 215 kfree:
 216         kfree(local_q);
 217 iounmap_1:
 218         scif_iounmap(remote_q, remote_size, scifdev);
 219         qp->outbound_q.rb_base = NULL;
 220 iounmap:
 221         scif_iounmap(qp->remote_qp, sizeof(struct scif_qp), scifdev);
 222         qp->remote_qp = NULL;
 223         return err;
 224 }
 225
 226 int scif_setup_qp_connect_response(struct scif_dev *scifdev,
 227                                    struct scif_qp *qp, u64 payload)
 228 {
 229         int err = 0;
 230         void *r_buf;
 231         int remote_size;
 232         phys_addr_t tmp_phys;
 233
 234         qp->remote_qp = scif_ioremap(payload, sizeof(struct scif_qp), scifdev);
 235
 236         if (!qp->remote_qp) {
 237                 err = -ENOMEM;
 238                 goto error;
 239         }
 240
 241         if (qp->remote_qp->magic != SCIFEP_MAGIC) {
 242                 dev_err(&scifdev->sdev->dev,
 243                         "SCIFEP_MAGIC mismatch between self %d remote %d\n",
 244                         scif_dev[scif_info.nodeid].node, scifdev->node);
 245                 err = -ENODEV;
 246                 goto error;
 247         }
 248
 249         tmp_phys = qp->remote_qp->local_buf;
 250         remote_size = qp->remote_qp->inbound_q.size;
 251         r_buf = scif_ioremap(tmp_phys, remote_size, scifdev);
 252
 253         if (!r_buf)
 254                 return -EIO;
 255
 256         qp->local_read = 0;
 257         scif_rb_init(&qp->outbound_q,
 258                      &qp->local_read,
 259                      &qp->remote_qp->local_write,
 260                      r_buf,
 261                      get_count_order(remote_size));
 262         /*
 263          * resetup the inbound_q now that we know where the
 264          * inbound_read really is.
 265          */
 266         scif_rb_init(&qp->inbound_q,
 267                      &qp->remote_qp->local_read,
 268                      &qp->local_write,
 269                      qp->inbound_q.rb_base,
 270                      get_count_order(qp->inbound_q.size));
 271 error:
 272         return err;
 273 }
 274
 275 static __always_inline void
 276 scif_send_msg_intr(struct scif_dev *scifdev)
 277 {
 278         struct scif_hw_dev *sdev = scifdev->sdev;
 279
 280         if (scifdev_is_p2p(scifdev))
 281                 sdev->hw_ops->send_p2p_intr(sdev, scifdev->rdb, &scifdev->mmio);
 282         else
 283                 sdev->hw_ops->send_intr(sdev, scifdev->rdb);
 284 }
 285
 286 int scif_qp_response(phys_addr_t phys, struct scif_dev *scifdev)
 287 {
 288         int err = 0;
 289         struct scifmsg msg;
 290
 291         err = scif_setup_qp_connect_response(scifdev, scifdev->qpairs, phys);
 292         if (!err) {
 293                 /*
 294                  * Now that everything is setup and mapped, we're ready
 295                  * to tell the peer about our queue's location
 296                  */
 297                 msg.uop = SCIF_INIT;
 298                 msg.dst.node = scifdev->node;
 299                 err = scif_nodeqp_send(scifdev, &msg);
 300         }
 301         return err;
 302 }
 303
 304 void scif_send_exit(struct scif_dev *scifdev)
 305 {
 306         struct scifmsg msg;
 307         int ret;
 308
 309         scifdev->exit = OP_IN_PROGRESS;
 310         msg.uop = SCIF_EXIT;
 311         msg.src.node = scif_info.nodeid;
 312         msg.dst.node = scifdev->node;
 313         ret = scif_nodeqp_send(scifdev, &msg);
 314         if (ret)
 315                 goto done;
 316         /* Wait for a SCIF_EXIT_ACK message */
 317         wait_event_timeout(scif_info.exitwq, scifdev->exit == OP_COMPLETED,
 318                            SCIF_NODE_ALIVE_TIMEOUT);
 319 done:
 320         scifdev->exit = OP_IDLE;
 321 }
 322
 323 int scif_setup_qp(struct scif_dev *scifdev)
 324 {
 325         int err = 0;
 326         int local_size;
 327         struct scif_qp *qp;
 328
 329         local_size = SCIF_NODE_QP_SIZE;
 330
 331         qp = kzalloc(sizeof(*qp), GFP_KERNEL);
 332         if (!qp) {
 333                 err = -ENOMEM;
 334                 return err;
 335         }
 336         qp->magic = SCIFEP_MAGIC;
 337         scifdev->qpairs = qp;
 338         err = scif_setup_qp_connect(qp, &scifdev->qp_dma_addr,
 339                                     local_size, scifdev);
 340         if (err)
 341                 goto free_qp;
 342         /*
 343          * We're as setup as we can be. The inbound_q is setup, w/o a usable
 344          * outbound q.  When we get a message, the read_ptr will be updated,
 345          * and we will pull the message.
 346          */
 347         return err;
 348 free_qp:
 349         kfree(scifdev->qpairs);
 350         scifdev->qpairs = NULL;
 351         return err;
 352 }
 353
 354 static void scif_p2p_freesg(struct scatterlist *sg)
 355 {
 356         kfree(sg);
 357 }
 358
 359 static struct scatterlist *
 360 scif_p2p_setsg(phys_addr_t pa, int page_size, int page_cnt)
 361 {
 362         struct scatterlist *sg;
 363         struct page *page;
 364         int i;
 365
 366         sg = kcalloc(page_cnt, sizeof(struct scatterlist), GFP_KERNEL);
 367         if (!sg)
 368                 return NULL;
 369         sg_init_table(sg, page_cnt);
 370         for (i = 0; i < page_cnt; i++) {
 371                 page = pfn_to_page(pa >> PAGE_SHIFT);
 372                 sg_set_page(&sg[i], page, page_size, 0);
 373                 pa += page_size;
 374         }
 375         return sg;
 376 }
 377
 378 /* Init p2p mappings required to access peerdev from scifdev */
 379 static struct scif_p2p_info *
 380 scif_init_p2p_info(struct scif_dev *scifdev, struct scif_dev *peerdev)
 381 {
 382         struct scif_p2p_info *p2p;
 383         int num_mmio_pages, num_aper_pages, sg_page_shift, err, num_aper_chunks;
 384         struct scif_hw_dev *psdev = peerdev->sdev;
 385         struct scif_hw_dev *sdev = scifdev->sdev;
 386
 387         num_mmio_pages = psdev->mmio->len >> PAGE_SHIFT;
 388         num_aper_pages = psdev->aper->len >> PAGE_SHIFT;
 389
 390         p2p = kzalloc(sizeof(*p2p), GFP_KERNEL);
 391         if (!p2p)
 392                 return NULL;
 393         p2p->ppi_sg[SCIF_PPI_MMIO] = scif_p2p_setsg(psdev->mmio->pa,
 394                                                     PAGE_SIZE, num_mmio_pages);
 395         if (!p2p->ppi_sg[SCIF_PPI_MMIO])
 396                 goto free_p2p;
 397         p2p->sg_nentries[SCIF_PPI_MMIO] = num_mmio_pages;
 398         sg_page_shift = get_order(min(psdev->aper->len, (u64)(1 << 30)));
 399         num_aper_chunks = num_aper_pages >> (sg_page_shift - PAGE_SHIFT);
 400         p2p->ppi_sg[SCIF_PPI_APER] = scif_p2p_setsg(psdev->aper->pa,
 401                                                     1 << sg_page_shift,
 402                                                     num_aper_chunks);
 403         p2p->sg_nentries[SCIF_PPI_APER] = num_aper_chunks;
 404         err = dma_map_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
 405                          num_mmio_pages, PCI_DMA_BIDIRECTIONAL);
 406         if (err != num_mmio_pages)
 407                 goto scif_p2p_free;
 408         err = dma_map_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_APER],
 409                          num_aper_chunks, PCI_DMA_BIDIRECTIONAL);
 410         if (err != num_aper_chunks)
 411                 goto dma_unmap;
 412         p2p->ppi_da[SCIF_PPI_MMIO] = sg_dma_address(p2p->ppi_sg[SCIF_PPI_MMIO]);
 413         p2p->ppi_da[SCIF_PPI_APER] = sg_dma_address(p2p->ppi_sg[SCIF_PPI_APER]);
 414         p2p->ppi_len[SCIF_PPI_MMIO] = num_mmio_pages;
 415         p2p->ppi_len[SCIF_PPI_APER] = num_aper_pages;
 416         p2p->ppi_peer_id = peerdev->node;
 417         return p2p;
 418 dma_unmap:
 419         dma_unmap_sg(&sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
 420                      p2p->sg_nentries[SCIF_PPI_MMIO], DMA_BIDIRECTIONAL);
 421 scif_p2p_free:
 422         scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
 423         scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
 424 free_p2p:
 425         kfree(p2p);
 426         return NULL;
 427 }
 428
 429 /**
 430  * scif_node_connect: Respond to SCIF_NODE_CONNECT interrupt message
 431  * @dst: Destination node
 432  *
 433  * Connect the src and dst node by setting up the p2p connection
 434  * between them. Management node here acts like a proxy.
 435  */
 436 static void scif_node_connect(struct scif_dev *scifdev, int dst)
 437 {
 438         struct scif_dev *dev_j = scifdev;
 439         struct scif_dev *dev_i = NULL;
 440         struct scif_p2p_info *p2p_ij = NULL;    /* bus addr for j from i */
 441         struct scif_p2p_info *p2p_ji = NULL;    /* bus addr for i from j */
 442         struct scif_p2p_info *p2p;
 443         struct list_head *pos, *tmp;
 444         struct scifmsg msg;
 445         int err;
 446         u64 tmppayload;
 447
 448         if (dst < 1 || dst > scif_info.maxid)
 449                 return;
 450
 451         dev_i = &scif_dev[dst];
 452
 453         if (!_scifdev_alive(dev_i))
 454                 return;
 455         /*
 456          * If the p2p connection is already setup or in the process of setting
 457          * up then just ignore this request. The requested node will get
 458          * informed by SCIF_NODE_ADD_ACK or SCIF_NODE_ADD_NACK
 459          */
 460         if (!list_empty(&dev_i->p2p)) {
 461                 list_for_each_safe(pos, tmp, &dev_i->p2p) {
 462                         p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
 463                         if (p2p->ppi_peer_id == dev_j->node)
 464                                 return;
 465                 }
 466         }
 467         p2p_ij = scif_init_p2p_info(dev_i, dev_j);
 468         if (!p2p_ij)
 469                 return;
 470         p2p_ji = scif_init_p2p_info(dev_j, dev_i);
 471         if (!p2p_ji)
 472                 return;
 473         list_add_tail(&p2p_ij->ppi_list, &dev_i->p2p);
 474         list_add_tail(&p2p_ji->ppi_list, &dev_j->p2p);
 475
 476         /*
 477          * Send a SCIF_NODE_ADD to dev_i, pass it its bus address
 478          * as seen from dev_j
 479          */
 480         msg.uop = SCIF_NODE_ADD;
 481         msg.src.node = dev_j->node;
 482         msg.dst.node = dev_i->node;
 483
 484         msg.payload[0] = p2p_ji->ppi_da[SCIF_PPI_APER];
 485         msg.payload[1] = p2p_ij->ppi_da[SCIF_PPI_MMIO];
 486         msg.payload[2] = p2p_ij->ppi_da[SCIF_PPI_APER];
 487         msg.payload[3] = p2p_ij->ppi_len[SCIF_PPI_APER] << PAGE_SHIFT;
 488
 489         err = scif_nodeqp_send(dev_i,  &msg);
 490         if (err) {
 491                 dev_err(&scifdev->sdev->dev,
 492                         "%s %d error %d\n", __func__, __LINE__, err);
 493                 return;
 494         }
 495
 496         /* Same as above but to dev_j */
 497         msg.uop = SCIF_NODE_ADD;
 498         msg.src.node = dev_i->node;
 499         msg.dst.node = dev_j->node;
 500
 501         tmppayload = msg.payload[0];
 502         msg.payload[0] = msg.payload[2];
 503         msg.payload[2] = tmppayload;
 504         msg.payload[1] = p2p_ji->ppi_da[SCIF_PPI_MMIO];
 505         msg.payload[3] = p2p_ji->ppi_len[SCIF_PPI_APER] << PAGE_SHIFT;
 506
 507         scif_nodeqp_send(dev_j, &msg);
 508 }
 509
 510 static void scif_p2p_setup(void)
 511 {
 512         int i, j;
 513
 514         if (!scif_info.p2p_enable)
 515                 return;
 516
 517         for (i = 1; i <= scif_info.maxid; i++)
 518                 if (!_scifdev_alive(&scif_dev[i]))
 519                         return;
 520
 521         for (i = 1; i <= scif_info.maxid; i++) {
 522                 for (j = 1; j <= scif_info.maxid; j++) {
 523                         struct scif_dev *scifdev = &scif_dev[i];
 524
 525                         if (i == j)
 526                                 continue;
 527                         scif_node_connect(scifdev, j);
 528                 }
 529         }
 530 }
 531
 532 void scif_qp_response_ack(struct work_struct *work)
 533 {
 534         struct scif_dev *scifdev = container_of(work, struct scif_dev,
 535                                                 init_msg_work);
 536         struct scif_peer_dev *spdev;
 537
 538         /* Drop the INIT message if it has already been received */
 539         if (_scifdev_alive(scifdev))
 540                 return;
 541
 542         spdev = scif_peer_register_device(scifdev);
 543         if (IS_ERR(spdev))
 544                 return;
 545
 546         if (scif_is_mgmt_node()) {
 547                 mutex_lock(&scif_info.conflock);
 548                 scif_p2p_setup();
 549                 mutex_unlock(&scif_info.conflock);
 550         }
 551 }
 552
 553 static char *message_types[] = {"BAD",
 554                                 "INIT",
 555                                 "EXIT",
 556                                 "SCIF_EXIT_ACK",
 557                                 "SCIF_NODE_ADD",
 558                                 "SCIF_NODE_ADD_ACK",
 559                                 "SCIF_NODE_ADD_NACK",
 560                                 "REMOVE_NODE",
 561                                 "REMOVE_NODE_ACK",
 562                                 "CNCT_REQ",
 563                                 "CNCT_GNT",
 564                                 "CNCT_GNTACK",
 565                                 "CNCT_GNTNACK",
 566                                 "CNCT_REJ",
 567                                 "DISCNCT",
 568                                 "DISCNT_ACK",
 569                                 "CLIENT_SENT",
 570                                 "CLIENT_RCVD",
 571                                 "SCIF_GET_NODE_INFO"};
 572
 573 static void
 574 scif_display_message(struct scif_dev *scifdev, struct scifmsg *msg,
 575                      const char *label)
 576 {
 577         if (!scif_info.en_msg_log)
 578                 return;
 579         if (msg->uop > SCIF_MAX_MSG) {
 580                 dev_err(&scifdev->sdev->dev,
 581                         "%s: unknown msg type %d\n", label, msg->uop);
 582                 return;
 583         }
 584         dev_info(&scifdev->sdev->dev,
 585                  "%s: msg type %s, src %d:%d, dest %d:%d payload 0x%llx:0x%llx:0x%llx:0x%llx\n",
 586                  label, message_types[msg->uop], msg->src.node, msg->src.port,
 587                  msg->dst.node, msg->dst.port, msg->payload[0], msg->payload[1],
 588                  msg->payload[2], msg->payload[3]);
 589 }
 590
 591 int _scif_nodeqp_send(struct scif_dev *scifdev, struct scifmsg *msg)
 592 {
 593         struct scif_qp *qp = scifdev->qpairs;
 594         int err = -ENOMEM, loop_cnt = 0;
 595
 596         scif_display_message(scifdev, msg, "Sent");
 597         if (!qp) {
 598                 err = -EINVAL;
 599                 goto error;
 600         }
 601         spin_lock(&qp->send_lock);
 602
 603         while ((err = scif_rb_write(&qp->outbound_q,
 604                                     msg, sizeof(struct scifmsg)))) {
 605                 mdelay(1);
 606 #define SCIF_NODEQP_SEND_TO_MSEC (3 * 1000)
 607                 if (loop_cnt++ > (SCIF_NODEQP_SEND_TO_MSEC)) {
 608                         err = -ENODEV;
 609                         break;
 610                 }
 611         }
 612         if (!err)
 613                 scif_rb_commit(&qp->outbound_q);
 614         spin_unlock(&qp->send_lock);
 615         if (!err) {
 616                 if (scifdev_self(scifdev))
 617                         /*
 618                          * For loopback we need to emulate an interrupt by
 619                          * queuing work for the queue handling real node
 620                          * Qp interrupts.
 621                          */
 622                         queue_work(scifdev->intr_wq, &scifdev->intr_bh);
 623                 else
 624                         scif_send_msg_intr(scifdev);
 625         }
 626 error:
 627         if (err)
 628                 dev_dbg(&scifdev->sdev->dev,
 629                         "%s %d error %d uop %d\n",
 630                          __func__, __LINE__, err, msg->uop);
 631         return err;
 632 }
 633
 634 /**
 635  * scif_nodeqp_send - Send a message on the node queue pair
 636  * @scifdev: Scif Device.
 637  * @msg: The message to be sent.
 638  */
 639 int scif_nodeqp_send(struct scif_dev *scifdev, struct scifmsg *msg)
 640 {
 641         int err;
 642         struct device *spdev = NULL;
 643
 644         if (msg->uop > SCIF_EXIT_ACK) {
 645                 /* Dont send messages once the exit flow has begun */
 646                 if (OP_IDLE != scifdev->exit)
 647                         return -ENODEV;
 648                 spdev = scif_get_peer_dev(scifdev);
 649                 if (IS_ERR(spdev)) {
 650                         err = PTR_ERR(spdev);
 651                         return err;
 652                 }
 653         }
 654         err = _scif_nodeqp_send(scifdev, msg);
 655         if (msg->uop > SCIF_EXIT_ACK)
 656                 scif_put_peer_dev(spdev);
 657         return err;
 658 }
 659
 660 /*
 661  * scif_misc_handler:
 662  *
 663  * Work queue handler for servicing miscellaneous SCIF tasks.
 664  * Examples include:
 665  * 1) Cleanup of zombie endpoints.
 666  */
 667 void scif_misc_handler(struct work_struct *work)
 668 {
 669         scif_cleanup_zombie_epd();
 670 }
 671
 672 /**
 673  * scif_init() - Respond to SCIF_INIT interrupt message
 674  * @scifdev:    Remote SCIF device node
 675  * @msg:        Interrupt message
 676  */
 677 static __always_inline void
 678 scif_init(struct scif_dev *scifdev, struct scifmsg *msg)
 679 {
 680         /*
 681          * Allow the thread waiting for device page updates for the peer QP DMA
 682          * address to complete initializing the inbound_q.
 683          */
 684         flush_delayed_work(&scifdev->qp_dwork);
 685         /*
 686          * Delegate the peer device registration to a workqueue, otherwise if
 687          * SCIF client probe (called during peer device registration) calls
 688          * scif_connect(..), it will block the message processing thread causing
 689          * a deadlock.
 690          */
 691         schedule_work(&scifdev->init_msg_work);
 692 }
 693
 694 /**
 695  * scif_exit() - Respond to SCIF_EXIT interrupt message
 696  * @scifdev:    Remote SCIF device node
 697  * @msg:        Interrupt message
 698  *
 699  * This function stops the SCIF interface for the node which sent
 700  * the SCIF_EXIT message and starts waiting for that node to
 701  * resetup the queue pair again.
 702  */
 703 static __always_inline void
 704 scif_exit(struct scif_dev *scifdev, struct scifmsg *unused)
 705 {
 706         scifdev->exit_ack_pending = true;
 707         if (scif_is_mgmt_node())
 708                 scif_disconnect_node(scifdev->node, false);
 709         else
 710                 scif_stop(scifdev);
 711         schedule_delayed_work(&scifdev->qp_dwork,
 712                               msecs_to_jiffies(1000));
 713 }
 714
 715 /**
 716  * scif_exitack() - Respond to SCIF_EXIT_ACK interrupt message
 717  * @scifdev:    Remote SCIF device node
 718  * @msg:        Interrupt message
 719  *
 720  */
 721 static __always_inline void
 722 scif_exit_ack(struct scif_dev *scifdev, struct scifmsg *unused)
 723 {
 724         scifdev->exit = OP_COMPLETED;
 725         wake_up(&scif_info.exitwq);
 726 }
 727
 728 /**
 729  * scif_node_add() - Respond to SCIF_NODE_ADD interrupt message
 730  * @scifdev:    Remote SCIF device node
 731  * @msg:        Interrupt message
 732  *
 733  * When the mgmt node driver has finished initializing a MIC node queue pair it
 734  * marks the node as online. It then looks for all currently online MIC cards
 735  * and send a SCIF_NODE_ADD message to identify the ID of the new card for
 736  * peer to peer initialization
 737  *
 738  * The local node allocates its incoming queue and sends its address in the
 739  * SCIF_NODE_ADD_ACK message back to the mgmt node, the mgmt node "reflects"
 740  * this message to the new node
 741  */
 742 static __always_inline void
 743 scif_node_add(struct scif_dev *scifdev, struct scifmsg *msg)
 744 {
 745         struct scif_dev *newdev;
 746         dma_addr_t qp_offset;
 747         int qp_connect;
 748         struct scif_hw_dev *sdev;
 749
 750         dev_dbg(&scifdev->sdev->dev,
 751                 "Scifdev %d:%d received NODE_ADD msg for node %d\n",
 752                 scifdev->node, msg->dst.node, msg->src.node);
 753         dev_dbg(&scifdev->sdev->dev,
 754                 "Remote address for this node's aperture %llx\n",
 755                 msg->payload[0]);
 756         newdev = &scif_dev[msg->src.node];
 757         newdev->node = msg->src.node;
 758         newdev->sdev = scif_dev[SCIF_MGMT_NODE].sdev;
 759         sdev = newdev->sdev;
 760
 761         if (scif_setup_intr_wq(newdev)) {
 762                 dev_err(&scifdev->sdev->dev,
 763                         "failed to setup interrupts for %d\n", msg->src.node);
 764                 goto interrupt_setup_error;
 765         }
 766         newdev->mmio.va = ioremap_nocache(msg->payload[1], sdev->mmio->len);
 767         if (!newdev->mmio.va) {
 768                 dev_err(&scifdev->sdev->dev,
 769                         "failed to map mmio for %d\n", msg->src.node);
 770                 goto mmio_map_error;
 771         }
 772         newdev->qpairs = kzalloc(sizeof(*newdev->qpairs), GFP_KERNEL);
 773         if (!newdev->qpairs)
 774                 goto qp_alloc_error;
 775         /*
 776          * Set the base address of the remote node's memory since it gets
 777          * added to qp_offset
 778          */
 779         newdev->base_addr = msg->payload[0];
 780
 781         qp_connect = scif_setup_qp_connect(newdev->qpairs, &qp_offset,
 782                                            SCIF_NODE_QP_SIZE, newdev);
 783         if (qp_connect) {
 784                 dev_err(&scifdev->sdev->dev,
 785                         "failed to setup qp_connect %d\n", qp_connect);
 786                 goto qp_connect_error;
 787         }
 788
 789         newdev->db = sdev->hw_ops->next_db(sdev);
 790         newdev->cookie = sdev->hw_ops->request_irq(sdev, scif_intr_handler,
 791                                                    "SCIF_INTR", newdev,
 792                                                    newdev->db);
 793         if (IS_ERR(newdev->cookie))
 794                 goto qp_connect_error;
 795         newdev->qpairs->magic = SCIFEP_MAGIC;
 796         newdev->qpairs->qp_state = SCIF_QP_OFFLINE;
 797
 798         msg->uop = SCIF_NODE_ADD_ACK;
 799         msg->dst.node = msg->src.node;
 800         msg->src.node = scif_info.nodeid;
 801         msg->payload[0] = qp_offset;
 802         msg->payload[2] = newdev->db;
 803         scif_nodeqp_send(&scif_dev[SCIF_MGMT_NODE], msg);
 804         return;
 805 qp_connect_error:
 806         kfree(newdev->qpairs);
 807         newdev->qpairs = NULL;
 808 qp_alloc_error:
 809         iounmap(newdev->mmio.va);
 810         newdev->mmio.va = NULL;
 811 mmio_map_error:
 812 interrupt_setup_error:
 813         dev_err(&scifdev->sdev->dev,
 814                 "node add failed for node %d\n", msg->src.node);
 815         msg->uop = SCIF_NODE_ADD_NACK;
 816         msg->dst.node = msg->src.node;
 817         msg->src.node = scif_info.nodeid;
 818         scif_nodeqp_send(&scif_dev[SCIF_MGMT_NODE], msg);
 819 }
 820
 821 void scif_poll_qp_state(struct work_struct *work)
 822 {
 823 #define SCIF_NODE_QP_RETRY 100
 824 #define SCIF_NODE_QP_TIMEOUT 100
 825         struct scif_dev *peerdev = container_of(work, struct scif_dev,
 826                                                         p2p_dwork.work);
 827         struct scif_qp *qp = &peerdev->qpairs[0];
 828
 829         if (qp->qp_state != SCIF_QP_ONLINE ||
 830             qp->remote_qp->qp_state != SCIF_QP_ONLINE) {
 831                 if (peerdev->p2p_retry++ == SCIF_NODE_QP_RETRY) {
 832                         dev_err(&peerdev->sdev->dev,
 833                                 "Warning: QP check timeout with state %d\n",
 834                                 qp->qp_state);
 835                         goto timeout;
 836                 }
 837                 schedule_delayed_work(&peerdev->p2p_dwork,
 838                                       msecs_to_jiffies(SCIF_NODE_QP_TIMEOUT));
 839                 return;
 840         }
 841         scif_peer_register_device(peerdev);
 842         return;
 843 timeout:
 844         dev_err(&peerdev->sdev->dev,
 845                 "%s %d remote node %d offline,  state = 0x%x\n",
 846                 __func__, __LINE__, peerdev->node, qp->qp_state);
 847         qp->remote_qp->qp_state = SCIF_QP_OFFLINE;
 848         scif_cleanup_scifdev(peerdev);
 849 }
 850
 851 /**
 852  * scif_node_add_ack() - Respond to SCIF_NODE_ADD_ACK interrupt message
 853  * @scifdev:    Remote SCIF device node
 854  * @msg:        Interrupt message
 855  *
 856  * After a MIC node receives the SCIF_NODE_ADD_ACK message it send this
 857  * message to the mgmt node to confirm the sequence is finished.
 858  *
 859  */
 860 static __always_inline void
 861 scif_node_add_ack(struct scif_dev *scifdev, struct scifmsg *msg)
 862 {
 863         struct scif_dev *peerdev;
 864         struct scif_qp *qp;
 865         struct scif_dev *dst_dev = &scif_dev[msg->dst.node];
 866
 867         dev_dbg(&scifdev->sdev->dev,
 868                 "Scifdev %d received SCIF_NODE_ADD_ACK msg src %d dst %d\n",
 869                 scifdev->node, msg->src.node, msg->dst.node);
 870         dev_dbg(&scifdev->sdev->dev,
 871                 "payload %llx %llx %llx %llx\n", msg->payload[0],
 872                 msg->payload[1], msg->payload[2], msg->payload[3]);
 873         if (scif_is_mgmt_node()) {
 874                 /*
 875                  * the lock serializes with scif_qp_response_ack. The mgmt node
 876                  * is forwarding the NODE_ADD_ACK message from src to dst we
 877                  * need to make sure that the dst has already received a
 878                  * NODE_ADD for src and setup its end of the qp to dst
 879                  */
 880                 mutex_lock(&scif_info.conflock);
 881                 msg->payload[1] = scif_info.maxid;
 882                 scif_nodeqp_send(dst_dev, msg);
 883                 mutex_unlock(&scif_info.conflock);
 884                 return;
 885         }
 886         peerdev = &scif_dev[msg->src.node];
 887         peerdev->sdev = scif_dev[SCIF_MGMT_NODE].sdev;
 888         peerdev->node = msg->src.node;
 889
 890         qp = &peerdev->qpairs[0];
 891
 892         if ((scif_setup_qp_connect_response(peerdev, &peerdev->qpairs[0],
 893                                             msg->payload[0])))
 894                 goto local_error;
 895         peerdev->rdb = msg->payload[2];
 896         qp->remote_qp->qp_state = SCIF_QP_ONLINE;
 897         schedule_delayed_work(&peerdev->p2p_dwork, 0);
 898         return;
 899 local_error:
 900         scif_cleanup_scifdev(peerdev);
 901 }
 902
 903 /**
 904  * scif_node_add_nack: Respond to SCIF_NODE_ADD_NACK interrupt message
 905  * @msg:        Interrupt message
 906  *
 907  * SCIF_NODE_ADD failed, so inform the waiting wq.
 908  */
 909 static __always_inline void
 910 scif_node_add_nack(struct scif_dev *scifdev, struct scifmsg *msg)
 911 {
 912         if (scif_is_mgmt_node()) {
 913                 struct scif_dev *dst_dev = &scif_dev[msg->dst.node];
 914
 915                 dev_dbg(&scifdev->sdev->dev,
 916                         "SCIF_NODE_ADD_NACK received from %d\n", scifdev->node);
 917                 scif_nodeqp_send(dst_dev, msg);
 918         }
 919 }
 920
 921 /*
 922  * scif_node_remove: Handle SCIF_NODE_REMOVE message
 923  * @msg: Interrupt message
 924  *
 925  * Handle node removal.
 926  */
 927 static __always_inline void
 928 scif_node_remove(struct scif_dev *scifdev, struct scifmsg *msg)
 929 {
 930         int node = msg->payload[0];
 931         struct scif_dev *scdev = &scif_dev[node];
 932
 933         scdev->node_remove_ack_pending = true;
 934         scif_handle_remove_node(node);
 935 }
 936
 937 /*
 938  * scif_node_remove_ack: Handle SCIF_NODE_REMOVE_ACK message
 939  * @msg: Interrupt message
 940  *
 941  * The peer has acked a SCIF_NODE_REMOVE message.
 942  */
 943 static __always_inline void
 944 scif_node_remove_ack(struct scif_dev *scifdev, struct scifmsg *msg)
 945 {
 946         struct scif_dev *sdev = &scif_dev[msg->payload[0]];
 947
 948         atomic_inc(&sdev->disconn_rescnt);
 949         wake_up(&sdev->disconn_wq);
 950 }
 951
 952 /**
 953  * scif_get_node_info: Respond to SCIF_GET_NODE_INFO interrupt message
 954  * @msg:        Interrupt message
 955  *
 956  * Retrieve node info i.e maxid and total from the mgmt node.
 957  */
 958 static __always_inline void
 959 scif_get_node_info_resp(struct scif_dev *scifdev, struct scifmsg *msg)
 960 {
 961         if (scif_is_mgmt_node()) {
 962                 swap(msg->dst.node, msg->src.node);
 963                 mutex_lock(&scif_info.conflock);
 964                 msg->payload[1] = scif_info.maxid;
 965                 msg->payload[2] = scif_info.total;
 966                 mutex_unlock(&scif_info.conflock);
 967                 scif_nodeqp_send(scifdev, msg);
 968         } else {
 969                 struct completion *node_info =
 970                         (struct completion *)msg->payload[3];
 971
 972                 mutex_lock(&scif_info.conflock);
 973                 scif_info.maxid = msg->payload[1];
 974                 scif_info.total = msg->payload[2];
 975                 complete_all(node_info);
 976                 mutex_unlock(&scif_info.conflock);
 977         }
 978 }
 979
 980 static void
 981 scif_msg_unknown(struct scif_dev *scifdev, struct scifmsg *msg)
 982 {
 983         /* Bogus Node Qp Message? */
 984         dev_err(&scifdev->sdev->dev,
 985                 "Unknown message 0x%xn scifdev->node 0x%x\n",
 986                 msg->uop, scifdev->node);
 987 }
 988
 989 static void (*scif_intr_func[SCIF_MAX_MSG + 1])
 990             (struct scif_dev *, struct scifmsg *msg) = {
 991         scif_msg_unknown,       /* Error */
 992         scif_init,              /* SCIF_INIT */
 993         scif_exit,              /* SCIF_EXIT */
 994         scif_exit_ack,          /* SCIF_EXIT_ACK */
 995         scif_node_add,          /* SCIF_NODE_ADD */
 996         scif_node_add_ack,      /* SCIF_NODE_ADD_ACK */
 997         scif_node_add_nack,     /* SCIF_NODE_ADD_NACK */
 998         scif_node_remove,       /* SCIF_NODE_REMOVE */
 999         scif_node_remove_ack,   /* SCIF_NODE_REMOVE_ACK */
1000         scif_cnctreq,           /* SCIF_CNCT_REQ */
1001         scif_cnctgnt,           /* SCIF_CNCT_GNT */
1002         scif_cnctgnt_ack,       /* SCIF_CNCT_GNTACK */
1003         scif_cnctgnt_nack,      /* SCIF_CNCT_GNTNACK */
1004         scif_cnctrej,           /* SCIF_CNCT_REJ */
1005         scif_discnct,           /* SCIF_DISCNCT */
1006         scif_discnt_ack,        /* SCIF_DISCNT_ACK */
1007         scif_clientsend,        /* SCIF_CLIENT_SENT */
1008         scif_clientrcvd,        /* SCIF_CLIENT_RCVD */
1009         scif_get_node_info_resp,/* SCIF_GET_NODE_INFO */
1010 };
1011
1012 /**
1013  * scif_nodeqp_msg_handler() - Common handler for node messages
1014  * @scifdev: Remote device to respond to
1015  * @qp: Remote memory pointer
1016  * @msg: The message to be handled.
1017  *
1018  * This routine calls the appropriate routine to handle a Node Qp
1019  * message receipt
1020  */
1021 static int scif_max_msg_id = SCIF_MAX_MSG;
1022
1023 static void
1024 scif_nodeqp_msg_handler(struct scif_dev *scifdev,
1025                         struct scif_qp *qp, struct scifmsg *msg)
1026 {
1027         scif_display_message(scifdev, msg, "Rcvd");
1028
1029         if (msg->uop > (u32)scif_max_msg_id) {
1030                 /* Bogus Node Qp Message? */
1031                 dev_err(&scifdev->sdev->dev,
1032                         "Unknown message 0x%xn scifdev->node 0x%x\n",
1033                         msg->uop, scifdev->node);
1034                 return;
1035         }
1036
1037         scif_intr_func[msg->uop](scifdev, msg);
1038 }
1039
1040 /**
1041  * scif_nodeqp_intrhandler() - Interrupt handler for node messages
1042  * @scifdev:    Remote device to respond to
1043  * @qp:         Remote memory pointer
1044  *
1045  * This routine is triggered by the interrupt mechanism.  It reads
1046  * messages from the node queue RB and calls the Node QP Message handling
1047  * routine.
1048  */
1049 void scif_nodeqp_intrhandler(struct scif_dev *scifdev, struct scif_qp *qp)
1050 {
1051         struct scifmsg msg;
1052         int read_size;
1053
1054         do {
1055                 read_size = scif_rb_get_next(&qp->inbound_q, &msg, sizeof(msg));
1056                 if (!read_size)
1057                         break;
1058                 scif_nodeqp_msg_handler(scifdev, qp, &msg);
1059                 /*
1060                  * The node queue pair is unmapped so skip the read pointer
1061                  * update after receipt of a SCIF_EXIT_ACK
1062                  */
1063                 if (SCIF_EXIT_ACK == msg.uop)
1064                         break;
1065                 scif_rb_update_read_ptr(&qp->inbound_q);
1066         } while (1);
1067 }
1068
1069 /**
1070  * scif_loopb_wq_handler - Loopback Workqueue Handler.
1071  * @work: loop back work
1072  *
1073  * This work queue routine is invoked by the loopback work queue handler.
1074  * It grabs the recv lock, dequeues any available messages from the head
1075  * of the loopback message list, calls the node QP message handler,
1076  * waits for it to return, then frees up this message and dequeues more
1077  * elements of the list if available.
1078  */
1079 static void scif_loopb_wq_handler(struct work_struct *unused)
1080 {
1081         struct scif_dev *scifdev = scif_info.loopb_dev;
1082         struct scif_qp *qp = scifdev->qpairs;
1083         struct scif_loopb_msg *msg;
1084
1085         do {
1086                 msg = NULL;
1087                 spin_lock(&qp->recv_lock);
1088                 if (!list_empty(&scif_info.loopb_recv_q)) {
1089                         msg = list_first_entry(&scif_info.loopb_recv_q,
1090                                                struct scif_loopb_msg,
1091                                                list);
1092                         list_del(&msg->list);
1093                 }
1094                 spin_unlock(&qp->recv_lock);
1095
1096                 if (msg) {
1097                         scif_nodeqp_msg_handler(scifdev, qp, &msg->msg);
1098                         kfree(msg);
1099                 }
1100         } while (msg);
1101 }
1102
1103 /**
1104  * scif_loopb_msg_handler() - Workqueue handler for loopback messages.
1105  * @scifdev: SCIF device
1106  * @qp: Queue pair.
1107  *
1108  * This work queue routine is triggered when a loopback message is received.
1109  *
1110  * We need special handling for receiving Node Qp messages on a loopback SCIF
1111  * device via two workqueues for receiving messages.
1112  *
1113  * The reason we need the extra workqueue which is not required with *normal*
1114  * non-loopback SCIF devices is the potential classic deadlock described below:
1115  *
1116  * Thread A tries to send a message on a loopback SCIF device and blocks since
1117  * there is no space in the RB while it has the send_lock held or another
1118  * lock called lock X for example.
1119  *
1120  * Thread B: The Loopback Node QP message receive workqueue receives the message
1121  * and tries to send a message (eg an ACK) to the loopback SCIF device. It tries
1122  * to grab the send lock again or lock X and deadlocks with Thread A. The RB
1123  * cannot be drained any further due to this classic deadlock.
1124  *
1125  * In order to avoid deadlocks as mentioned above we have an extra level of
1126  * indirection achieved by having two workqueues.
1127  * 1) The first workqueue whose handler is scif_loopb_msg_handler reads
1128  * messages from the Node QP RB, adds them to a list and queues work for the
1129  * second workqueue.
1130  *
1131  * 2) The second workqueue whose handler is scif_loopb_wq_handler dequeues
1132  * messages from the list, handles them, frees up the memory and dequeues
1133  * more elements from the list if possible.
1134  */
1135 int
1136 scif_loopb_msg_handler(struct scif_dev *scifdev, struct scif_qp *qp)
1137 {
1138         int read_size;
1139         struct scif_loopb_msg *msg;
1140
1141         do {
1142                 msg = kmalloc(sizeof(*msg), GFP_KERNEL);
1143                 if (!msg)
1144                         return -ENOMEM;
1145                 read_size = scif_rb_get_next(&qp->inbound_q, &msg->msg,
1146                                              sizeof(struct scifmsg));
1147                 if (read_size != sizeof(struct scifmsg)) {
1148                         kfree(msg);
1149                         scif_rb_update_read_ptr(&qp->inbound_q);
1150                         break;
1151                 }
1152                 spin_lock(&qp->recv_lock);
1153                 list_add_tail(&msg->list, &scif_info.loopb_recv_q);
1154                 spin_unlock(&qp->recv_lock);
1155                 queue_work(scif_info.loopb_wq, &scif_info.loopb_work);
1156                 scif_rb_update_read_ptr(&qp->inbound_q);
1157         } while (read_size == sizeof(struct scifmsg));
1158         return read_size;
1159 }
1160
1161 /**
1162  * scif_setup_loopback_qp - One time setup work for Loopback Node Qp.
1163  * @scifdev: SCIF device
1164  *
1165  * Sets up the required loopback workqueues, queue pairs and ring buffers
1166  */
1167 int scif_setup_loopback_qp(struct scif_dev *scifdev)
1168 {
1169         int err = 0;
1170         void *local_q;
1171         struct scif_qp *qp;
1172         struct scif_peer_dev *spdev;
1173
1174         err = scif_setup_intr_wq(scifdev);
1175         if (err)
1176                 goto exit;
1177         INIT_LIST_HEAD(&scif_info.loopb_recv_q);
1178         snprintf(scif_info.loopb_wqname, sizeof(scif_info.loopb_wqname),
1179                  "SCIF LOOPB %d", scifdev->node);
1180         scif_info.loopb_wq =
1181                 alloc_ordered_workqueue(scif_info.loopb_wqname, 0);
1182         if (!scif_info.loopb_wq) {
1183                 err = -ENOMEM;
1184                 goto destroy_intr;
1185         }
1186         INIT_WORK(&scif_info.loopb_work, scif_loopb_wq_handler);
1187         /* Allocate Self Qpair */
1188         scifdev->qpairs = kzalloc(sizeof(*scifdev->qpairs), GFP_KERNEL);
1189         if (!scifdev->qpairs) {
1190                 err = -ENOMEM;
1191                 goto destroy_loopb_wq;
1192         }
1193
1194         qp = scifdev->qpairs;
1195         qp->magic = SCIFEP_MAGIC;
1196         spin_lock_init(&qp->send_lock);
1197         spin_lock_init(&qp->recv_lock);
1198
1199         local_q = kzalloc(SCIF_NODE_QP_SIZE, GFP_KERNEL);
1200         if (!local_q) {
1201                 err = -ENOMEM;
1202                 goto free_qpairs;
1203         }
1204         /*
1205          * For loopback the inbound_q and outbound_q are essentially the same
1206          * since the Node sends a message on the loopback interface to the
1207          * outbound_q which is then received on the inbound_q.
1208          */
1209         scif_rb_init(&qp->outbound_q,
1210                      &qp->local_read,
1211                      &qp->local_write,
1212                      local_q, get_count_order(SCIF_NODE_QP_SIZE));
1213
1214         scif_rb_init(&qp->inbound_q,
1215                      &qp->local_read,
1216                      &qp->local_write,
1217                      local_q, get_count_order(SCIF_NODE_QP_SIZE));
1218         scif_info.nodeid = scifdev->node;
1219         spdev = scif_peer_register_device(scifdev);
1220         if (IS_ERR(spdev)) {
1221                 err = PTR_ERR(spdev);
1222                 goto free_local_q;
1223         }
1224         scif_info.loopb_dev = scifdev;
1225         return err;
1226 free_local_q:
1227         kfree(local_q);
1228 free_qpairs:
1229         kfree(scifdev->qpairs);
1230 destroy_loopb_wq:
1231         destroy_workqueue(scif_info.loopb_wq);
1232 destroy_intr:
1233         scif_destroy_intr_wq(scifdev);
1234 exit:
1235         return err;
1236 }
1237
1238 /**
1239  * scif_destroy_loopback_qp - One time uninit work for Loopback Node Qp
1240  * @scifdev: SCIF device
1241  *
1242  * Destroys the workqueues and frees up the Ring Buffer and Queue Pair memory.
1243  */
1244 int scif_destroy_loopback_qp(struct scif_dev *scifdev)
1245 {
1246         struct scif_peer_dev *spdev;
1247
1248         rcu_read_lock();
1249         spdev = rcu_dereference(scifdev->spdev);
1250         rcu_read_unlock();
1251         if (spdev)
1252                 scif_peer_unregister_device(spdev);
1253         destroy_workqueue(scif_info.loopb_wq);
1254         scif_destroy_intr_wq(scifdev);
1255         kfree(scifdev->qpairs->outbound_q.rb_base);
1256         kfree(scifdev->qpairs);
1257         scifdev->sdev = NULL;
1258         scif_info.loopb_dev = NULL;
1259         return 0;
1260 }
1261
1262 void scif_destroy_p2p(struct scif_dev *scifdev)
1263 {
1264         struct scif_dev *peer_dev;
1265         struct scif_p2p_info *p2p;
1266         struct list_head *pos, *tmp;
1267         int bd;
1268
1269         mutex_lock(&scif_info.conflock);
1270         /* Free P2P mappings in the given node for all its peer nodes */
1271         list_for_each_safe(pos, tmp, &scifdev->p2p) {
1272                 p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
1273                 dma_unmap_sg(&scifdev->sdev->dev, p2p->ppi_sg[SCIF_PPI_MMIO],
1274                              p2p->sg_nentries[SCIF_PPI_MMIO],
1275                              DMA_BIDIRECTIONAL);
1276                 dma_unmap_sg(&scifdev->sdev->dev, p2p->ppi_sg[SCIF_PPI_APER],
1277                              p2p->sg_nentries[SCIF_PPI_APER],
1278                              DMA_BIDIRECTIONAL);
1279                 scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
1280                 scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
1281                 list_del(pos);
1282                 kfree(p2p);
1283         }
1284
1285         /* Free P2P mapping created in the peer nodes for the given node */
1286         for (bd = SCIF_MGMT_NODE + 1; bd <= scif_info.maxid; bd++) {
1287                 peer_dev = &scif_dev[bd];
1288                 list_for_each_safe(pos, tmp, &peer_dev->p2p) {
1289                         p2p = list_entry(pos, struct scif_p2p_info, ppi_list);
1290                         if (p2p->ppi_peer_id == scifdev->node) {
1291                                 dma_unmap_sg(&peer_dev->sdev->dev,
1292                                              p2p->ppi_sg[SCIF_PPI_MMIO],
1293                                              p2p->sg_nentries[SCIF_PPI_MMIO],
1294                                              DMA_BIDIRECTIONAL);
1295                                 dma_unmap_sg(&peer_dev->sdev->dev,
1296                                              p2p->ppi_sg[SCIF_PPI_APER],
1297                                              p2p->sg_nentries[SCIF_PPI_APER],
1298                                              DMA_BIDIRECTIONAL);
1299                                 scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_MMIO]);
1300                                 scif_p2p_freesg(p2p->ppi_sg[SCIF_PPI_APER]);
1301                                 list_del(pos);
1302                                 kfree(p2p);
1303                         }
1304                 }
1305         }
1306         mutex_unlock(&scif_info.conflock);
1307 }