Free Electrons

Embedded Linux Experts

  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
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
/*
 * SCSI RDMA Protocol lib functions
 *
 * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/kfifo.h>
#include <linux/scatterlist.h>
#include <linux/dma-mapping.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_tgt.h>
#include <scsi/srp.h>
#include <scsi/libsrp.h>

enum srp_task_attributes {
	SRP_SIMPLE_TASK = 0,
	SRP_HEAD_TASK = 1,
	SRP_ORDERED_TASK = 2,
	SRP_ACA_TASK = 4
};

/* tmp - will replace with SCSI logging stuff */
#define eprintk(fmt, args...)					\
do {								\
	printk("%s(%d) " fmt, __func__, __LINE__, ##args);	\
} while (0)
/* #define dprintk eprintk */
#define dprintk(fmt, args...)

static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
			     struct srp_buf **ring)
{
	int i;
	struct iu_entry *iue;

	q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
	if (!q->pool)
		return -ENOMEM;
	q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
	if (!q->items)
		goto free_pool;

	spin_lock_init(&q->lock);
	kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *));

	for (i = 0, iue = q->items; i < max; i++) {
		kfifo_in(&q->queue, (void *) &iue, sizeof(void *));
		iue->sbuf = ring[i];
		iue++;
	}
	return 0;

	kfree(q->items);
free_pool:
	kfree(q->pool);
	return -ENOMEM;
}

static void srp_iu_pool_free(struct srp_queue *q)
{
	kfree(q->items);
	kfree(q->pool);
}

static struct srp_buf **srp_ring_alloc(struct device *dev,
				       size_t max, size_t size)
{
	int i;
	struct srp_buf **ring;

	ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
	if (!ring)
		return NULL;

	for (i = 0; i < max; i++) {
		ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
		if (!ring[i])
			goto out;
		ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
						  GFP_KERNEL);
		if (!ring[i]->buf)
			goto out;
	}
	return ring;

out:
	for (i = 0; i < max && ring[i]; i++) {
		if (ring[i]->buf)
			dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
		kfree(ring[i]);
	}
	kfree(ring);

	return NULL;
}

static void srp_ring_free(struct device *dev, struct srp_buf **ring, size_t max,
			  size_t size)
{
	int i;

	for (i = 0; i < max; i++) {
		dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
		kfree(ring[i]);
	}
	kfree(ring);
}

int srp_target_alloc(struct srp_target *target, struct device *dev,
		     size_t nr, size_t iu_size)
{
	int err;

	spin_lock_init(&target->lock);
	INIT_LIST_HEAD(&target->cmd_queue);

	target->dev = dev;
	dev_set_drvdata(target->dev, target);

	target->srp_iu_size = iu_size;
	target->rx_ring_size = nr;
	target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
	if (!target->rx_ring)
		return -ENOMEM;
	err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
	if (err)
		goto free_ring;

	return 0;

free_ring:
	srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
	return -ENOMEM;
}
EXPORT_SYMBOL_GPL(srp_target_alloc);

void srp_target_free(struct srp_target *target)
{
	srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
		      target->srp_iu_size);
	srp_iu_pool_free(&target->iu_queue);
}
EXPORT_SYMBOL_GPL(srp_target_free);

struct iu_entry *srp_iu_get(struct srp_target *target)
{
	struct iu_entry *iue = NULL;

	if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
		sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
			WARN_ONCE(1, "unexpected fifo state");
			return NULL;
	}
	if (!iue)
		return iue;
	iue->target = target;
	INIT_LIST_HEAD(&iue->ilist);
	iue->flags = 0;
	return iue;
}
EXPORT_SYMBOL_GPL(srp_iu_get);

void srp_iu_put(struct iu_entry *iue)
{
	kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
			sizeof(void *), &iue->target->iu_queue.lock);
}
EXPORT_SYMBOL_GPL(srp_iu_put);

static int srp_direct_data(struct scsi_cmnd *sc, struct srp_direct_buf *md,
			   enum dma_data_direction dir, srp_rdma_t rdma_io,
			   int dma_map, int ext_desc)
{
	struct iu_entry *iue = NULL;
	struct scatterlist *sg = NULL;
	int err, nsg = 0, len;

	if (dma_map) {
		iue = (struct iu_entry *) sc->SCp.ptr;
		sg = scsi_sglist(sc);

		dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
			md->len, scsi_sg_count(sc));

		nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
				 DMA_BIDIRECTIONAL);
		if (!nsg) {
			printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
			return 0;
		}
		len = min(scsi_bufflen(sc), md->len);
	} else
		len = md->len;

	err = rdma_io(sc, sg, nsg, md, 1, dir, len);

	if (dma_map)
		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

	return err;
}

static int srp_indirect_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
			     struct srp_indirect_buf *id,
			     enum dma_data_direction dir, srp_rdma_t rdma_io,
			     int dma_map, int ext_desc)
{
	struct iu_entry *iue = NULL;
	struct srp_direct_buf *md = NULL;
	struct scatterlist dummy, *sg = NULL;
	dma_addr_t token = 0;
	int err = 0;
	int nmd, nsg = 0, len;

	if (dma_map || ext_desc) {
		iue = (struct iu_entry *) sc->SCp.ptr;
		sg = scsi_sglist(sc);

		dprintk("%p %u %u %d %d\n",
			iue, scsi_bufflen(sc), id->len,
			cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
	}

	nmd = id->table_desc.len / sizeof(struct srp_direct_buf);

	if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) ||
	    (dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
		md = &id->desc_list[0];
		goto rdma;
	}

	if (ext_desc && dma_map) {
		md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
				&token, GFP_KERNEL);
		if (!md) {
			eprintk("Can't get dma memory %u\n", id->table_desc.len);
			return -ENOMEM;
		}

		sg_init_one(&dummy, md, id->table_desc.len);
		sg_dma_address(&dummy) = token;
		sg_dma_len(&dummy) = id->table_desc.len;
		err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
			      id->table_desc.len);
		if (err) {
			eprintk("Error copying indirect table %d\n", err);
			goto free_mem;
		}
	} else {
		eprintk("This command uses external indirect buffer\n");
		return -EINVAL;
	}

rdma:
	if (dma_map) {
		nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
				 DMA_BIDIRECTIONAL);
		if (!nsg) {
			eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
			err = -EIO;
			goto free_mem;
		}
		len = min(scsi_bufflen(sc), id->len);
	} else
		len = id->len;

	err = rdma_io(sc, sg, nsg, md, nmd, dir, len);

	if (dma_map)
		dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);

free_mem:
	if (token && dma_map)
		dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);

	return err;
}

static int data_out_desc_size(struct srp_cmd *cmd)
{
	int size = 0;
	u8 fmt = cmd->buf_fmt >> 4;

	switch (fmt) {
	case SRP_NO_DATA_DESC:
		break;
	case SRP_DATA_DESC_DIRECT:
		size = sizeof(struct srp_direct_buf);
		break;
	case SRP_DATA_DESC_INDIRECT:
		size = sizeof(struct srp_indirect_buf) +
			sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
		break;
	default:
		eprintk("client error. Invalid data_out_format %x\n", fmt);
		break;
	}
	return size;
}

/*
 * TODO: this can be called multiple times for a single command if it
 * has very long data.
 */
int srp_transfer_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
		      srp_rdma_t rdma_io, int dma_map, int ext_desc)
{
	struct srp_direct_buf *md;
	struct srp_indirect_buf *id;
	enum dma_data_direction dir;
	int offset, err = 0;
	u8 format;

	offset = cmd->add_cdb_len & ~3;

	dir = srp_cmd_direction(cmd);
	if (dir == DMA_FROM_DEVICE)
		offset += data_out_desc_size(cmd);

	if (dir == DMA_TO_DEVICE)
		format = cmd->buf_fmt >> 4;
	else
		format = cmd->buf_fmt & ((1U << 4) - 1);

	switch (format) {
	case SRP_NO_DATA_DESC:
		break;
	case SRP_DATA_DESC_DIRECT:
		md = (struct srp_direct_buf *)
			(cmd->add_data + offset);
		err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
		break;
	case SRP_DATA_DESC_INDIRECT:
		id = (struct srp_indirect_buf *)
			(cmd->add_data + offset);
		err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
					ext_desc);
		break;
	default:
		eprintk("Unknown format %d %x\n", dir, format);
		err = -EINVAL;
	}

	return err;
}
EXPORT_SYMBOL_GPL(srp_transfer_data);

static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
{
	struct srp_direct_buf *md;
	struct srp_indirect_buf *id;
	int len = 0, offset = cmd->add_cdb_len & ~3;
	u8 fmt;

	if (dir == DMA_TO_DEVICE)
		fmt = cmd->buf_fmt >> 4;
	else {
		fmt = cmd->buf_fmt & ((1U << 4) - 1);
		offset += data_out_desc_size(cmd);
	}

	switch (fmt) {
	case SRP_NO_DATA_DESC:
		break;
	case SRP_DATA_DESC_DIRECT:
		md = (struct srp_direct_buf *) (cmd->add_data + offset);
		len = md->len;
		break;
	case SRP_DATA_DESC_INDIRECT:
		id = (struct srp_indirect_buf *) (cmd->add_data + offset);
		len = id->len;
		break;
	default:
		eprintk("invalid data format %x\n", fmt);
		break;
	}
	return len;
}

int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
		  u64 itn_id, u64 addr)
{
	enum dma_data_direction dir;
	struct scsi_cmnd *sc;
	int tag, len, err;

	switch (cmd->task_attr) {
	case SRP_SIMPLE_TASK:
		tag = MSG_SIMPLE_TAG;
		break;
	case SRP_ORDERED_TASK:
		tag = MSG_ORDERED_TAG;
		break;
	case SRP_HEAD_TASK:
		tag = MSG_HEAD_TAG;
		break;
	default:
		eprintk("Task attribute %d not supported\n", cmd->task_attr);
		tag = MSG_ORDERED_TAG;
	}

	dir = srp_cmd_direction(cmd);
	len = vscsis_data_length(cmd, dir);

	dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
		cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);

	sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
	if (!sc)
		return -ENOMEM;

	sc->SCp.ptr = info;
	memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
	sc->sdb.length = len;
	sc->sdb.table.sgl = (void *) (unsigned long) addr;
	sc->tag = tag;
	err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
				     cmd->tag);
	if (err)
		scsi_host_put_command(shost, sc);

	return err;
}
EXPORT_SYMBOL_GPL(srp_cmd_queue);

MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
MODULE_AUTHOR("FUJITA Tomonori");
MODULE_LICENSE("GPL");