drivers/infiniband/hw/amso1100/c2_vq.c

   1 /*
   2  * Copyright (c) 2005 Ammasso, Inc. All rights reserved.
   3  * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
   4  *
   5  * This software is available to you under a choice of one of two
   6  * licenses.  You may choose to be licensed under the terms of the GNU
   7  * General Public License (GPL) Version 2, available from the file
   8  * COPYING in the main directory of this source tree, or the
   9  * OpenIB.org BSD license below:
  10  *
  11  *     Redistribution and use in source and binary forms, with or
  12  *     without modification, are permitted provided that the following
  13  *     conditions are met:
  14  *
  15  *      - Redistributions of source code must retain the above
  16  *        copyright notice, this list of conditions and the following
  17  *        disclaimer.
  18  *
  19  *      - Redistributions in binary form must reproduce the above
  20  *        copyright notice, this list of conditions and the following
  21  *        disclaimer in the documentation and/or other materials
  22  *        provided with the distribution.
  23  *
  24  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  28  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  29  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  30  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  31  * SOFTWARE.
  32  */
  33 #include <linux/slab.h>
  34 #include <linux/spinlock.h>
  35
  36 #include "c2_vq.h"
  37 #include "c2_provider.h"
  38
  39 /*
  40  * Verbs Request Objects:
  41  *
  42  * VQ Request Objects are allocated by the kernel verbs handlers.
  43  * They contain a wait object, a refcnt, an atomic bool indicating that the
  44  * adapter has replied, and a copy of the verb reply work request.
  45  * A pointer to the VQ Request Object is passed down in the context
  46  * field of the work request message, and reflected back by the adapter
  47  * in the verbs reply message.  The function handle_vq() in the interrupt
  48  * path will use this pointer to:
  49  *      1) append a copy of the verbs reply message
  50  *      2) mark that the reply is ready
  51  *      3) wake up the kernel verbs handler blocked awaiting the reply.
  52  *
  53  *
  54  * The kernel verbs handlers do a "get" to put a 2nd reference on the
  55  * VQ Request object.  If the kernel verbs handler exits before the adapter
  56  * can respond, this extra reference will keep the VQ Request object around
  57  * until the adapter's reply can be processed.  The reason we need this is
  58  * because a pointer to this object is stuffed into the context field of
  59  * the verbs work request message, and reflected back in the reply message.
  60  * It is used in the interrupt handler (handle_vq()) to wake up the appropriate
  61  * kernel verb handler that is blocked awaiting the verb reply.
  62  * So handle_vq() will do a "put" on the object when it's done accessing it.
  63  * NOTE:  If we guarantee that the kernel verb handler will never bail before
  64  *        getting the reply, then we don't need these refcnts.
  65  *
  66  *
  67  * VQ Request objects are freed by the kernel verbs handlers only
  68  * after the verb has been processed, or when the adapter fails and
  69  * does not reply.
  70  *
  71  *
  72  * Verbs Reply Buffers:
  73  *
  74  * VQ Reply bufs are local host memory copies of a
  75  * outstanding Verb Request reply
  76  * message.  The are always allocated by the kernel verbs handlers, and _may_ be
  77  * freed by either the kernel verbs handler -or- the interrupt handler.  The
  78  * kernel verbs handler _must_ free the repbuf, then free the vq request object
  79  * in that order.
  80  */
  81
  82 int vq_init(struct c2_dev *c2dev)
  83 {
  84         sprintf(c2dev->vq_cache_name, "c2-vq:dev%c",
  85                 (char) ('0' + c2dev->devnum));
  86         c2dev->host_msg_cache =
  87             kmem_cache_create(c2dev->vq_cache_name, c2dev->rep_vq.msg_size, 0,
  88                               SLAB_HWCACHE_ALIGN, NULL);
  89         if (c2dev->host_msg_cache == NULL) {
  90                 return -ENOMEM;
  91         }
  92         return 0;
  93 }
  94
  95 void vq_term(struct c2_dev *c2dev)
  96 {
  97         kmem_cache_destroy(c2dev->host_msg_cache);
  98 }
  99
 100 /* vq_req_alloc - allocate a VQ Request Object and initialize it.
 101  * The refcnt is set to 1.
 102  */
 103 struct c2_vq_req *vq_req_alloc(struct c2_dev *c2dev)
 104 {
 105         struct c2_vq_req *r;
 106
 107         r = kmalloc(sizeof(struct c2_vq_req), GFP_KERNEL);
 108         if (r) {
 109                 init_waitqueue_head(&r->wait_object);
 110                 r->reply_msg = (u64) NULL;
 111                 r->event = 0;
 112                 r->cm_id = NULL;
 113                 r->qp = NULL;
 114                 atomic_set(&r->refcnt, 1);
 115                 atomic_set(&r->reply_ready, 0);
 116         }
 117         return r;
 118 }
 119
 120
 121 /* vq_req_free - free the VQ Request Object.  It is assumed the verbs handler
 122  * has already free the VQ Reply Buffer if it existed.
 123  */
 124 void vq_req_free(struct c2_dev *c2dev, struct c2_vq_req *r)
 125 {
 126         r->reply_msg = (u64) NULL;
 127         if (atomic_dec_and_test(&r->refcnt)) {
 128                 kfree(r);
 129         }
 130 }
 131
 132 /* vq_req_get - reference a VQ Request Object.  Done
 133  * only in the kernel verbs handlers.
 134  */
 135 void vq_req_get(struct c2_dev *c2dev, struct c2_vq_req *r)
 136 {
 137         atomic_inc(&r->refcnt);
 138 }
 139
 140
 141 /* vq_req_put - dereference and potentially free a VQ Request Object.
 142  *
 143  * This is only called by handle_vq() on the
 144  * interrupt when it is done processing
 145  * a verb reply message.  If the associated
 146  * kernel verbs handler has already bailed,
 147  * then this put will actually free the VQ
 148  * Request object _and_ the VQ Reply Buffer
 149  * if it exists.
 150  */
 151 void vq_req_put(struct c2_dev *c2dev, struct c2_vq_req *r)
 152 {
 153         if (atomic_dec_and_test(&r->refcnt)) {
 154                 if (r->reply_msg != (u64) NULL)
 155                         vq_repbuf_free(c2dev,
 156                                        (void *) (unsigned long) r->reply_msg);
 157                 kfree(r);
 158         }
 159 }
 160
 161
 162 /*
 163  * vq_repbuf_alloc - allocate a VQ Reply Buffer.
 164  */
 165 void *vq_repbuf_alloc(struct c2_dev *c2dev)
 166 {
 167         return kmem_cache_alloc(c2dev->host_msg_cache, GFP_ATOMIC);
 168 }
 169
 170 /*
 171  * vq_send_wr - post a verbs request message to the Verbs Request Queue.
 172  * If a message is not available in the MQ, then block until one is available.
 173  * NOTE: handle_mq() on the interrupt context will wake up threads blocked here.
 174  * When the adapter drains the Verbs Request Queue,
 175  * it inserts MQ index 0 in to the
 176  * adapter->host activity fifo and interrupts the host.
 177  */
 178 int vq_send_wr(struct c2_dev *c2dev, union c2wr *wr)
 179 {
 180         void *msg;
 181         wait_queue_t __wait;
 182
 183         /*
 184          * grab adapter vq lock
 185          */
 186         spin_lock(&c2dev->vqlock);
 187
 188         /*
 189          * allocate msg
 190          */
 191         msg = c2_mq_alloc(&c2dev->req_vq);
 192
 193         /*
 194          * If we cannot get a msg, then we'll wait
 195          * When a messages are available, the int handler will wake_up()
 196          * any waiters.
 197          */
 198         while (msg == NULL) {
 199                 pr_debug("%s:%d no available msg in VQ, waiting...\n",
 200                        __FUNCTION__, __LINE__);
 201                 init_waitqueue_entry(&__wait, current);
 202                 add_wait_queue(&c2dev->req_vq_wo, &__wait);
 203                 spin_unlock(&c2dev->vqlock);
 204                 for (;;) {
 205                         set_current_state(TASK_INTERRUPTIBLE);
 206                         if (!c2_mq_full(&c2dev->req_vq)) {
 207                                 break;
 208                         }
 209                         if (!signal_pending(current)) {
 210                                 schedule_timeout(1 * HZ);       /* 1 second... */
 211                                 continue;
 212                         }
 213                         set_current_state(TASK_RUNNING);
 214                         remove_wait_queue(&c2dev->req_vq_wo, &__wait);
 215                         return -EINTR;
 216                 }
 217                 set_current_state(TASK_RUNNING);
 218                 remove_wait_queue(&c2dev->req_vq_wo, &__wait);
 219                 spin_lock(&c2dev->vqlock);
 220                 msg = c2_mq_alloc(&c2dev->req_vq);
 221         }
 222
 223         /*
 224          * copy wr into adapter msg
 225          */
 226         memcpy(msg, wr, c2dev->req_vq.msg_size);
 227
 228         /*
 229          * post msg
 230          */
 231         c2_mq_produce(&c2dev->req_vq);
 232
 233         /*
 234          * release adapter vq lock
 235          */
 236         spin_unlock(&c2dev->vqlock);
 237         return 0;
 238 }
 239
 240
 241 /*
 242  * vq_wait_for_reply - block until the adapter posts a Verb Reply Message.
 243  */
 244 int vq_wait_for_reply(struct c2_dev *c2dev, struct c2_vq_req *req)
 245 {
 246         if (!wait_event_timeout(req->wait_object,
 247                                 atomic_read(&req->reply_ready),
 248                                 60*HZ))
 249                 return -ETIMEDOUT;
 250
 251         return 0;
 252 }
 253
 254 /*
 255  * vq_repbuf_free - Free a Verbs Reply Buffer.
 256  */
 257 void vq_repbuf_free(struct c2_dev *c2dev, void *reply)
 258 {
 259         kmem_cache_free(c2dev->host_msg_cache, reply);
 260 }