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1/*
2 * SCSI RDMA Protocol lib functions
3 *
4 * Copyright (C) 2006 FUJITA Tomonori <tomof@acm.org>
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation; either version 2 of the
9 * License, or (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19 * 02110-1301 USA
20 */
21#include <linux/err.h>
22#include <linux/slab.h>
23#include <linux/kfifo.h>
24#include <linux/scatterlist.h>
25#include <linux/dma-mapping.h>
26#include <linux/module.h>
27#include <scsi/scsi.h>
28#include <scsi/scsi_cmnd.h>
29#include <scsi/scsi_tcq.h>
30#include <scsi/scsi_tgt.h>
31#include <scsi/srp.h>
32#include <scsi/libsrp.h>
33
34enum srp_task_attributes {
35 SRP_SIMPLE_TASK = 0,
36 SRP_HEAD_TASK = 1,
37 SRP_ORDERED_TASK = 2,
38 SRP_ACA_TASK = 4
39};
40
41/* tmp - will replace with SCSI logging stuff */
42#define eprintk(fmt, args...) \
43do { \
44 printk("%s(%d) " fmt, __func__, __LINE__, ##args); \
45} while (0)
46/* #define dprintk eprintk */
47#define dprintk(fmt, args...)
48
49static int srp_iu_pool_alloc(struct srp_queue *q, size_t max,
50 struct srp_buf **ring)
51{
52 int i;
53 struct iu_entry *iue;
54
55 q->pool = kcalloc(max, sizeof(struct iu_entry *), GFP_KERNEL);
56 if (!q->pool)
57 return -ENOMEM;
58 q->items = kcalloc(max, sizeof(struct iu_entry), GFP_KERNEL);
59 if (!q->items)
60 goto free_pool;
61
62 spin_lock_init(&q->lock);
63 kfifo_init(&q->queue, (void *) q->pool, max * sizeof(void *));
64
65 for (i = 0, iue = q->items; i < max; i++) {
66 kfifo_in(&q->queue, (void *) &iue, sizeof(void *));
67 iue->sbuf = ring[i];
68 iue++;
69 }
70 return 0;
71
72 kfree(q->items);
73free_pool:
74 kfree(q->pool);
75 return -ENOMEM;
76}
77
78static void srp_iu_pool_free(struct srp_queue *q)
79{
80 kfree(q->items);
81 kfree(q->pool);
82}
83
84static struct srp_buf **srp_ring_alloc(struct device *dev,
85 size_t max, size_t size)
86{
87 int i;
88 struct srp_buf **ring;
89
90 ring = kcalloc(max, sizeof(struct srp_buf *), GFP_KERNEL);
91 if (!ring)
92 return NULL;
93
94 for (i = 0; i < max; i++) {
95 ring[i] = kzalloc(sizeof(struct srp_buf), GFP_KERNEL);
96 if (!ring[i])
97 goto out;
98 ring[i]->buf = dma_alloc_coherent(dev, size, &ring[i]->dma,
99 GFP_KERNEL);
100 if (!ring[i]->buf)
101 goto out;
102 }
103 return ring;
104
105out:
106 for (i = 0; i < max && ring[i]; i++) {
107 if (ring[i]->buf)
108 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
109 kfree(ring[i]);
110 }
111 kfree(ring);
112
113 return NULL;
114}
115
116static void srp_ring_free(struct device *dev, struct srp_buf **ring, size_t max,
117 size_t size)
118{
119 int i;
120
121 for (i = 0; i < max; i++) {
122 dma_free_coherent(dev, size, ring[i]->buf, ring[i]->dma);
123 kfree(ring[i]);
124 }
125 kfree(ring);
126}
127
128int srp_target_alloc(struct srp_target *target, struct device *dev,
129 size_t nr, size_t iu_size)
130{
131 int err;
132
133 spin_lock_init(&target->lock);
134 INIT_LIST_HEAD(&target->cmd_queue);
135
136 target->dev = dev;
137 dev_set_drvdata(target->dev, target);
138
139 target->srp_iu_size = iu_size;
140 target->rx_ring_size = nr;
141 target->rx_ring = srp_ring_alloc(target->dev, nr, iu_size);
142 if (!target->rx_ring)
143 return -ENOMEM;
144 err = srp_iu_pool_alloc(&target->iu_queue, nr, target->rx_ring);
145 if (err)
146 goto free_ring;
147
148 return 0;
149
150free_ring:
151 srp_ring_free(target->dev, target->rx_ring, nr, iu_size);
152 return -ENOMEM;
153}
154EXPORT_SYMBOL_GPL(srp_target_alloc);
155
156void srp_target_free(struct srp_target *target)
157{
158 srp_ring_free(target->dev, target->rx_ring, target->rx_ring_size,
159 target->srp_iu_size);
160 srp_iu_pool_free(&target->iu_queue);
161}
162EXPORT_SYMBOL_GPL(srp_target_free);
163
164struct iu_entry *srp_iu_get(struct srp_target *target)
165{
166 struct iu_entry *iue = NULL;
167
168 if (kfifo_out_locked(&target->iu_queue.queue, (void *) &iue,
169 sizeof(void *), &target->iu_queue.lock) != sizeof(void *)) {
170 WARN_ONCE(1, "unexpected fifo state");
171 return NULL;
172 }
173 if (!iue)
174 return iue;
175 iue->target = target;
176 INIT_LIST_HEAD(&iue->ilist);
177 iue->flags = 0;
178 return iue;
179}
180EXPORT_SYMBOL_GPL(srp_iu_get);
181
182void srp_iu_put(struct iu_entry *iue)
183{
184 kfifo_in_locked(&iue->target->iu_queue.queue, (void *) &iue,
185 sizeof(void *), &iue->target->iu_queue.lock);
186}
187EXPORT_SYMBOL_GPL(srp_iu_put);
188
189static int srp_direct_data(struct scsi_cmnd *sc, struct srp_direct_buf *md,
190 enum dma_data_direction dir, srp_rdma_t rdma_io,
191 int dma_map, int ext_desc)
192{
193 struct iu_entry *iue = NULL;
194 struct scatterlist *sg = NULL;
195 int err, nsg = 0, len;
196
197 if (dma_map) {
198 iue = (struct iu_entry *) sc->SCp.ptr;
199 sg = scsi_sglist(sc);
200
201 dprintk("%p %u %u %d\n", iue, scsi_bufflen(sc),
202 md->len, scsi_sg_count(sc));
203
204 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
205 DMA_BIDIRECTIONAL);
206 if (!nsg) {
207 printk("fail to map %p %d\n", iue, scsi_sg_count(sc));
208 return 0;
209 }
210 len = min(scsi_bufflen(sc), md->len);
211 } else
212 len = md->len;
213
214 err = rdma_io(sc, sg, nsg, md, 1, dir, len);
215
216 if (dma_map)
217 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
218
219 return err;
220}
221
222static int srp_indirect_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
223 struct srp_indirect_buf *id,
224 enum dma_data_direction dir, srp_rdma_t rdma_io,
225 int dma_map, int ext_desc)
226{
227 struct iu_entry *iue = NULL;
228 struct srp_direct_buf *md = NULL;
229 struct scatterlist dummy, *sg = NULL;
230 dma_addr_t token = 0;
231 int err = 0;
232 int nmd, nsg = 0, len;
233
234 if (dma_map || ext_desc) {
235 iue = (struct iu_entry *) sc->SCp.ptr;
236 sg = scsi_sglist(sc);
237
238 dprintk("%p %u %u %d %d\n",
239 iue, scsi_bufflen(sc), id->len,
240 cmd->data_in_desc_cnt, cmd->data_out_desc_cnt);
241 }
242
243 nmd = id->table_desc.len / sizeof(struct srp_direct_buf);
244
245 if ((dir == DMA_FROM_DEVICE && nmd == cmd->data_in_desc_cnt) ||
246 (dir == DMA_TO_DEVICE && nmd == cmd->data_out_desc_cnt)) {
247 md = &id->desc_list[0];
248 goto rdma;
249 }
250
251 if (ext_desc && dma_map) {
252 md = dma_alloc_coherent(iue->target->dev, id->table_desc.len,
253 &token, GFP_KERNEL);
254 if (!md) {
255 eprintk("Can't get dma memory %u\n", id->table_desc.len);
256 return -ENOMEM;
257 }
258
259 sg_init_one(&dummy, md, id->table_desc.len);
260 sg_dma_address(&dummy) = token;
261 sg_dma_len(&dummy) = id->table_desc.len;
262 err = rdma_io(sc, &dummy, 1, &id->table_desc, 1, DMA_TO_DEVICE,
263 id->table_desc.len);
264 if (err) {
265 eprintk("Error copying indirect table %d\n", err);
266 goto free_mem;
267 }
268 } else {
269 eprintk("This command uses external indirect buffer\n");
270 return -EINVAL;
271 }
272
273rdma:
274 if (dma_map) {
275 nsg = dma_map_sg(iue->target->dev, sg, scsi_sg_count(sc),
276 DMA_BIDIRECTIONAL);
277 if (!nsg) {
278 eprintk("fail to map %p %d\n", iue, scsi_sg_count(sc));
279 err = -EIO;
280 goto free_mem;
281 }
282 len = min(scsi_bufflen(sc), id->len);
283 } else
284 len = id->len;
285
286 err = rdma_io(sc, sg, nsg, md, nmd, dir, len);
287
288 if (dma_map)
289 dma_unmap_sg(iue->target->dev, sg, nsg, DMA_BIDIRECTIONAL);
290
291free_mem:
292 if (token && dma_map)
293 dma_free_coherent(iue->target->dev, id->table_desc.len, md, token);
294
295 return err;
296}
297
298static int data_out_desc_size(struct srp_cmd *cmd)
299{
300 int size = 0;
301 u8 fmt = cmd->buf_fmt >> 4;
302
303 switch (fmt) {
304 case SRP_NO_DATA_DESC:
305 break;
306 case SRP_DATA_DESC_DIRECT:
307 size = sizeof(struct srp_direct_buf);
308 break;
309 case SRP_DATA_DESC_INDIRECT:
310 size = sizeof(struct srp_indirect_buf) +
311 sizeof(struct srp_direct_buf) * cmd->data_out_desc_cnt;
312 break;
313 default:
314 eprintk("client error. Invalid data_out_format %x\n", fmt);
315 break;
316 }
317 return size;
318}
319
320/*
321 * TODO: this can be called multiple times for a single command if it
322 * has very long data.
323 */
324int srp_transfer_data(struct scsi_cmnd *sc, struct srp_cmd *cmd,
325 srp_rdma_t rdma_io, int dma_map, int ext_desc)
326{
327 struct srp_direct_buf *md;
328 struct srp_indirect_buf *id;
329 enum dma_data_direction dir;
330 int offset, err = 0;
331 u8 format;
332
333 offset = cmd->add_cdb_len & ~3;
334
335 dir = srp_cmd_direction(cmd);
336 if (dir == DMA_FROM_DEVICE)
337 offset += data_out_desc_size(cmd);
338
339 if (dir == DMA_TO_DEVICE)
340 format = cmd->buf_fmt >> 4;
341 else
342 format = cmd->buf_fmt & ((1U << 4) - 1);
343
344 switch (format) {
345 case SRP_NO_DATA_DESC:
346 break;
347 case SRP_DATA_DESC_DIRECT:
348 md = (struct srp_direct_buf *)
349 (cmd->add_data + offset);
350 err = srp_direct_data(sc, md, dir, rdma_io, dma_map, ext_desc);
351 break;
352 case SRP_DATA_DESC_INDIRECT:
353 id = (struct srp_indirect_buf *)
354 (cmd->add_data + offset);
355 err = srp_indirect_data(sc, cmd, id, dir, rdma_io, dma_map,
356 ext_desc);
357 break;
358 default:
359 eprintk("Unknown format %d %x\n", dir, format);
360 err = -EINVAL;
361 }
362
363 return err;
364}
365EXPORT_SYMBOL_GPL(srp_transfer_data);
366
367static int vscsis_data_length(struct srp_cmd *cmd, enum dma_data_direction dir)
368{
369 struct srp_direct_buf *md;
370 struct srp_indirect_buf *id;
371 int len = 0, offset = cmd->add_cdb_len & ~3;
372 u8 fmt;
373
374 if (dir == DMA_TO_DEVICE)
375 fmt = cmd->buf_fmt >> 4;
376 else {
377 fmt = cmd->buf_fmt & ((1U << 4) - 1);
378 offset += data_out_desc_size(cmd);
379 }
380
381 switch (fmt) {
382 case SRP_NO_DATA_DESC:
383 break;
384 case SRP_DATA_DESC_DIRECT:
385 md = (struct srp_direct_buf *) (cmd->add_data + offset);
386 len = md->len;
387 break;
388 case SRP_DATA_DESC_INDIRECT:
389 id = (struct srp_indirect_buf *) (cmd->add_data + offset);
390 len = id->len;
391 break;
392 default:
393 eprintk("invalid data format %x\n", fmt);
394 break;
395 }
396 return len;
397}
398
399int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
400 u64 itn_id, u64 addr)
401{
402 enum dma_data_direction dir;
403 struct scsi_cmnd *sc;
404 int tag, len, err;
405
406 switch (cmd->task_attr) {
407 case SRP_SIMPLE_TASK:
408 tag = MSG_SIMPLE_TAG;
409 break;
410 case SRP_ORDERED_TASK:
411 tag = MSG_ORDERED_TAG;
412 break;
413 case SRP_HEAD_TASK:
414 tag = MSG_HEAD_TAG;
415 break;
416 default:
417 eprintk("Task attribute %d not supported\n", cmd->task_attr);
418 tag = MSG_ORDERED_TAG;
419 }
420
421 dir = srp_cmd_direction(cmd);
422 len = vscsis_data_length(cmd, dir);
423
424 dprintk("%p %x %lx %d %d %d %llx\n", info, cmd->cdb[0],
425 cmd->lun, dir, len, tag, (unsigned long long) cmd->tag);
426
427 sc = scsi_host_get_command(shost, dir, GFP_KERNEL);
428 if (!sc)
429 return -ENOMEM;
430
431 sc->SCp.ptr = info;
432 memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
433 sc->sdb.length = len;
434 sc->sdb.table.sgl = (void *) (unsigned long) addr;
435 sc->tag = tag;
436 err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
437 cmd->tag);
438 if (err)
439 scsi_host_put_command(shost, sc);
440
441 return err;
442}
443EXPORT_SYMBOL_GPL(srp_cmd_queue);
444
445MODULE_DESCRIPTION("SCSI RDMA Protocol lib functions");
446MODULE_AUTHOR("FUJITA Tomonori");
447MODULE_LICENSE("GPL");