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