summaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/hw/amso1100/c2_vq.c
blob: cfdacb1ec279b15fb2f0ef43eb4789e6bd3ab654 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
/*
 * Copyright (c) 2005 Ammasso, Inc. All rights reserved.
 * Copyright (c) 2005 Open Grid Computing, Inc. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "c2_vq.h"
#include "c2_provider.h"

/*
 * Verbs Request Objects:
 *
 * VQ Request Objects are allocated by the kernel verbs handlers.
 * They contain a wait object, a refcnt, an atomic bool indicating that the
 * adapter has replied, and a copy of the verb reply work request.
 * A pointer to the VQ Request Object is passed down in the context
 * field of the work request message, and reflected back by the adapter
 * in the verbs reply message.  The function handle_vq() in the interrupt
 * path will use this pointer to:
 * 	1) append a copy of the verbs reply message
 * 	2) mark that the reply is ready
 * 	3) wake up the kernel verbs handler blocked awaiting the reply.
 *
 *
 * The kernel verbs handlers do a "get" to put a 2nd reference on the
 * VQ Request object.  If the kernel verbs handler exits before the adapter
 * can respond, this extra reference will keep the VQ Request object around
 * until the adapter's reply can be processed.  The reason we need this is
 * because a pointer to this object is stuffed into the context field of
 * the verbs work request message, and reflected back in the reply message.
 * It is used in the interrupt handler (handle_vq()) to wake up the appropriate
 * kernel verb handler that is blocked awaiting the verb reply.
 * So handle_vq() will do a "put" on the object when it's done accessing it.
 * NOTE:  If we guarantee that the kernel verb handler will never bail before
 *        getting the reply, then we don't need these refcnts.
 *
 *
 * VQ Request objects are freed by the kernel verbs handlers only
 * after the verb has been processed, or when the adapter fails and
 * does not reply.
 *
 *
 * Verbs Reply Buffers:
 *
 * VQ Reply bufs are local host memory copies of a
 * outstanding Verb Request reply
 * message.  The are always allocated by the kernel verbs handlers, and _may_ be
 * freed by either the kernel verbs handler -or- the interrupt handler.  The
 * kernel verbs handler _must_ free the repbuf, then free the vq request object
 * in that order.
 */

int vq_init(struct c2_dev *c2dev)
{
	sprintf(c2dev->vq_cache_name, "c2-vq:dev%c",
		(char) ('0' + c2dev->devnum));
	c2dev->host_msg_cache =
	    kmem_cache_create(c2dev->vq_cache_name, c2dev->rep_vq.msg_size, 0,
			      SLAB_HWCACHE_ALIGN, NULL);
	if (c2dev->host_msg_cache == NULL) {
		return -ENOMEM;
	}
	return 0;
}

void vq_term(struct c2_dev *c2dev)
{
	kmem_cache_destroy(c2dev->host_msg_cache);
}

/* vq_req_alloc - allocate a VQ Request Object and initialize it.
 * The refcnt is set to 1.
 */
struct c2_vq_req *vq_req_alloc(struct c2_dev *c2dev)
{
	struct c2_vq_req *r;

	r = kmalloc(sizeof(struct c2_vq_req), GFP_KERNEL);
	if (r) {
		init_waitqueue_head(&r->wait_object);
		r->reply_msg = (u64) NULL;
		r->event = 0;
		r->cm_id = NULL;
		r->qp = NULL;
		atomic_set(&r->refcnt, 1);
		atomic_set(&r->reply_ready, 0);
	}
	return r;
}


/* vq_req_free - free the VQ Request Object.  It is assumed the verbs handler
 * has already free the VQ Reply Buffer if it existed.
 */
void vq_req_free(struct c2_dev *c2dev, struct c2_vq_req *r)
{
	r->reply_msg = (u64) NULL;
	if (atomic_dec_and_test(&r->refcnt)) {
		kfree(r);
	}
}

/* vq_req_get - reference a VQ Request Object.  Done
 * only in the kernel verbs handlers.
 */
void vq_req_get(struct c2_dev *c2dev, struct c2_vq_req *r)
{
	atomic_inc(&r->refcnt);
}


/* vq_req_put - dereference and potentially free a VQ Request Object.
 *
 * This is only called by handle_vq() on the
 * interrupt when it is done processing
 * a verb reply message.  If the associated
 * kernel verbs handler has already bailed,
 * then this put will actually free the VQ
 * Request object _and_ the VQ Reply Buffer
 * if it exists.
 */
void vq_req_put(struct c2_dev *c2dev, struct c2_vq_req *r)
{
	if (atomic_dec_and_test(&r->refcnt)) {
		if (r->reply_msg != (u64) NULL)
			vq_repbuf_free(c2dev,
				       (void *) (unsigned long) r->reply_msg);
		kfree(r);
	}
}


/*
 * vq_repbuf_alloc - allocate a VQ Reply Buffer.
 */
void *vq_repbuf_alloc(struct c2_dev *c2dev)
{
	return kmem_cache_alloc(c2dev->host_msg_cache, GFP_ATOMIC);
}

/*
 * vq_send_wr - post a verbs request message to the Verbs Request Queue.
 * If a message is not available in the MQ, then block until one is available.
 * NOTE: handle_mq() on the interrupt context will wake up threads blocked here.
 * When the adapter drains the Verbs Request Queue,
 * it inserts MQ index 0 in to the
 * adapter->host activity fifo and interrupts the host.
 */
int vq_send_wr(struct c2_dev *c2dev, union c2wr *wr)
{
	void *msg;
	wait_queue_t __wait;

	/*
	 * grab adapter vq lock
	 */
	spin_lock(&c2dev->vqlock);

	/*
	 * allocate msg
	 */
	msg = c2_mq_alloc(&c2dev->req_vq);

	/*
	 * If we cannot get a msg, then we'll wait
	 * When a messages are available, the int handler will wake_up()
	 * any waiters.
	 */
	while (msg == NULL) {
		pr_debug("%s:%d no available msg in VQ, waiting...\n",
		       __FUNCTION__, __LINE__);
		init_waitqueue_entry(&__wait, current);
		add_wait_queue(&c2dev->req_vq_wo, &__wait);
		spin_unlock(&c2dev->vqlock);
		for (;;) {
			set_current_state(TASK_INTERRUPTIBLE);
			if (!c2_mq_full(&c2dev->req_vq)) {
				break;
			}
			if (!signal_pending(current)) {
				schedule_timeout(1 * HZ);	/* 1 second... */
				continue;
			}
			set_current_state(TASK_RUNNING);
			remove_wait_queue(&c2dev->req_vq_wo, &__wait);
			return -EINTR;
		}
		set_current_state(TASK_RUNNING);
		remove_wait_queue(&c2dev->req_vq_wo, &__wait);
		spin_lock(&c2dev->vqlock);
		msg = c2_mq_alloc(&c2dev->req_vq);
	}

	/*
	 * copy wr into adapter msg
	 */
	memcpy(msg, wr, c2dev->req_vq.msg_size);

	/*
	 * post msg
	 */
	c2_mq_produce(&c2dev->req_vq);

	/*
	 * release adapter vq lock
	 */
	spin_unlock(&c2dev->vqlock);
	return 0;
}


/*
 * vq_wait_for_reply - block until the adapter posts a Verb Reply Message.
 */
int vq_wait_for_reply(struct c2_dev *c2dev, struct c2_vq_req *req)
{
	if (!wait_event_timeout(req->wait_object,
				atomic_read(&req->reply_ready),
				60*HZ))
		return -ETIMEDOUT;

	return 0;
}

/*
 * vq_repbuf_free - Free a Verbs Reply Buffer.
 */
void vq_repbuf_free(struct c2_dev *c2dev, void *reply)
{
	kmem_cache_free(c2dev->host_msg_cache, reply);
}
OpenPOWER on IntegriCloud