aboutsummaryrefslogtreecommitdiff
path: root/drivers/scsi/cxgb3i/cxgb3i_ddp.c
blob: 344fd53b9954c263ef1189ee489e40d54cd5055a (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
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
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
/*
 * cxgb3i_ddp.c: Chelsio S3xx iSCSI DDP Manager.
 *
 * Copyright (c) 2008 Chelsio Communications, Inc.
 *
 * 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.
 *
 * Written by: Karen Xie (kxie@chelsio.com)
 */

#include <linux/skbuff.h>
#include <linux/scatterlist.h>

/* from cxgb3 LLD */
#include "common.h"
#include "t3_cpl.h"
#include "t3cdev.h"
#include "cxgb3_ctl_defs.h"
#include "cxgb3_offload.h"
#include "firmware_exports.h"

#include "cxgb3i_ddp.h"

#define ddp_log_error(fmt...) printk(KERN_ERR "cxgb3i_ddp: ERR! " fmt)
#define ddp_log_warn(fmt...)  printk(KERN_WARNING "cxgb3i_ddp: WARN! " fmt)
#define ddp_log_info(fmt...)  printk(KERN_INFO "cxgb3i_ddp: " fmt)

#ifdef __DEBUG_CXGB3I_DDP__
#define ddp_log_debug(fmt, args...) \
	printk(KERN_INFO "cxgb3i_ddp: %s - " fmt, __func__ , ## args)
#else
#define ddp_log_debug(fmt...)
#endif

/*
 * iSCSI Direct Data Placement
 *
 * T3 h/w can directly place the iSCSI Data-In or Data-Out PDU's payload into
 * pre-posted final destination host-memory buffers based on the Initiator
 * Task Tag (ITT) in Data-In or Target Task Tag (TTT) in Data-Out PDUs.
 *
 * The host memory address is programmed into h/w in the format of pagepod
 * entries.
 * The location of the pagepod entry is encoded into ddp tag which is used or
 * is the base for ITT/TTT.
 */

#define DDP_PGIDX_MAX		4
#define DDP_THRESHOLD	2048
static unsigned char ddp_page_order[DDP_PGIDX_MAX] = {0, 1, 2, 4};
static unsigned char ddp_page_shift[DDP_PGIDX_MAX] = {12, 13, 14, 16};
static unsigned char page_idx = DDP_PGIDX_MAX;

/*
 * functions to program the pagepod in h/w
 */
static inline void ulp_mem_io_set_hdr(struct sk_buff *skb, unsigned int addr)
{
	struct ulp_mem_io *req = (struct ulp_mem_io *)skb->head;

	req->wr.wr_lo = 0;
	req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_BYPASS));
	req->cmd_lock_addr = htonl(V_ULP_MEMIO_ADDR(addr >> 5) |
				   V_ULPTX_CMD(ULP_MEM_WRITE));
	req->len = htonl(V_ULP_MEMIO_DATA_LEN(PPOD_SIZE >> 5) |
			 V_ULPTX_NFLITS((PPOD_SIZE >> 3) + 1));
}

static int set_ddp_map(struct cxgb3i_ddp_info *ddp, struct pagepod_hdr *hdr,
		       unsigned int idx, unsigned int npods,
		       struct cxgb3i_gather_list *gl)
{
	unsigned int pm_addr = (idx << PPOD_SIZE_SHIFT) + ddp->llimit;
	int i;

	for (i = 0; i < npods; i++, idx++, pm_addr += PPOD_SIZE) {
		struct sk_buff *skb = ddp->gl_skb[idx];
		struct pagepod *ppod;
		int j, pidx;

		/* hold on to the skb until we clear the ddp mapping */
		skb_get(skb);

		ulp_mem_io_set_hdr(skb, pm_addr);
		ppod = (struct pagepod *)
		       (skb->head + sizeof(struct ulp_mem_io));
		memcpy(&(ppod->hdr), hdr, sizeof(struct pagepod));
		for (pidx = 4 * i, j = 0; j < 5; ++j, ++pidx)
			ppod->addr[j] = pidx < gl->nelem ?
				     cpu_to_be64(gl->phys_addr[pidx]) : 0UL;

		skb->priority = CPL_PRIORITY_CONTROL;
		cxgb3_ofld_send(ddp->tdev, skb);
	}
	return 0;
}

static void clear_ddp_map(struct cxgb3i_ddp_info *ddp, unsigned int tag,
			 unsigned int idx, unsigned int npods)
{
	unsigned int pm_addr = (idx << PPOD_SIZE_SHIFT) + ddp->llimit;
	int i;

	for (i = 0; i < npods; i++, idx++, pm_addr += PPOD_SIZE) {
		struct sk_buff *skb = ddp->gl_skb[idx];

		if (!skb) {
			ddp_log_error("ddp tag 0x%x, 0x%x, %d/%u, skb NULL.\n",
					tag, idx, i, npods);
			continue;
		}
		ddp->gl_skb[idx] = NULL;
		memset((skb->head + sizeof(struct ulp_mem_io)), 0, PPOD_SIZE);
		ulp_mem_io_set_hdr(skb, pm_addr);
		skb->priority = CPL_PRIORITY_CONTROL;
		cxgb3_ofld_send(ddp->tdev, skb);
	}
}

static inline int ddp_find_unused_entries(struct cxgb3i_ddp_info *ddp,
					  unsigned int start, unsigned int max,
					  unsigned int count,
					  struct cxgb3i_gather_list *gl)
{
	unsigned int i, j, k;

	/* not enough entries */
	if ((max - start) < count)
		return -EBUSY;

	max -= count;
	spin_lock(&ddp->map_lock);
	for (i = start; i < max;) {
		for (j = 0, k = i; j < count; j++, k++) {
			if (ddp->gl_map[k])
				break;
		}
		if (j == count) {
			for (j = 0, k = i; j < count; j++, k++)
				ddp->gl_map[k] = gl;
			spin_unlock(&ddp->map_lock);
			return i;
		}
		i += j + 1;
	}
	spin_unlock(&ddp->map_lock);
	return -EBUSY;
}

static inline void ddp_unmark_entries(struct cxgb3i_ddp_info *ddp,
				      int start, int count)
{
	spin_lock(&ddp->map_lock);
	memset(&ddp->gl_map[start], 0,
	       count * sizeof(struct cxgb3i_gather_list *));
	spin_unlock(&ddp->map_lock);
}

static inline void ddp_free_gl_skb(struct cxgb3i_ddp_info *ddp,
				   int idx, int count)
{
	int i;

	for (i = 0; i < count; i++, idx++)
		if (ddp->gl_skb[idx]) {
			kfree_skb(ddp->gl_skb[idx]);
			ddp->gl_skb[idx] = NULL;
		}
}

static inline int ddp_alloc_gl_skb(struct cxgb3i_ddp_info *ddp, int idx,
				   int count, gfp_t gfp)
{
	int i;

	for (i = 0; i < count; i++) {
		struct sk_buff *skb = alloc_skb(sizeof(struct ulp_mem_io) +
						PPOD_SIZE, gfp);
		if (skb) {
			ddp->gl_skb[idx + i] = skb;
			skb_put(skb, sizeof(struct ulp_mem_io) + PPOD_SIZE);
		} else {
			ddp_free_gl_skb(ddp, idx, i);
			return -ENOMEM;
		}
	}
	return 0;
}

/**
 * cxgb3i_ddp_find_page_index - return ddp page index for a given page size
 * @pgsz: page size
 * return the ddp page index, if no match is found return DDP_PGIDX_MAX.
 */
int cxgb3i_ddp_find_page_index(unsigned long pgsz)
{
	int i;

	for (i = 0; i < DDP_PGIDX_MAX; i++) {
		if (pgsz == (1UL << ddp_page_shift[i]))
			return i;
	}
	ddp_log_debug("ddp page size 0x%lx not supported.\n", pgsz);
	return DDP_PGIDX_MAX;
}

/**
 * cxgb3i_ddp_adjust_page_table - adjust page table with PAGE_SIZE
 * return the ddp page index, if no match is found return DDP_PGIDX_MAX.
 */
int cxgb3i_ddp_adjust_page_table(void)
{
	int i;
	unsigned int base_order, order;

	if (PAGE_SIZE < (1UL << ddp_page_shift[0])) {
		ddp_log_info("PAGE_SIZE 0x%lx too small, min. 0x%lx.\n",
				PAGE_SIZE, 1UL << ddp_page_shift[0]);
		return -EINVAL;
	}

	base_order = get_order(1UL << ddp_page_shift[0]);
	order = get_order(1 << PAGE_SHIFT);
	for (i = 0; i < DDP_PGIDX_MAX; i++) {
		/* first is the kernel page size, then just doubling the size */
		ddp_page_order[i] = order - base_order + i;
		ddp_page_shift[i] = PAGE_SHIFT + i;
	}
	return 0;
}

static inline void ddp_gl_unmap(struct pci_dev *pdev,
				struct cxgb3i_gather_list *gl)
{
	int i;

	for (i = 0; i < gl->nelem; i++)
		pci_unmap_page(pdev, gl->phys_addr[i], PAGE_SIZE,
			       PCI_DMA_FROMDEVICE);
}

static inline int ddp_gl_map(struct pci_dev *pdev,
			     struct cxgb3i_gather_list *gl)
{
	int i;

	for (i = 0; i < gl->nelem; i++) {
		gl->phys_addr[i] = pci_map_page(pdev, gl->pages[i], 0,
						PAGE_SIZE,
						PCI_DMA_FROMDEVICE);
		if (unlikely(pci_dma_mapping_error(pdev, gl->phys_addr[i])))
			goto unmap;
	}

	return i;

unmap:
	if (i) {
		unsigned int nelem = gl->nelem;

		gl->nelem = i;
		ddp_gl_unmap(pdev, gl);
		gl->nelem = nelem;
	}
	return -ENOMEM;
}

/**
 * cxgb3i_ddp_make_gl - build ddp page buffer list
 * @xferlen: total buffer length
 * @sgl: page buffer scatter-gather list
 * @sgcnt: # of page buffers
 * @pdev: pci_dev, used for pci map
 * @gfp: allocation mode
 *
 * construct a ddp page buffer list from the scsi scattergather list.
 * coalesce buffers as much as possible, and obtain dma addresses for
 * each page.
 *
 * Return the cxgb3i_gather_list constructed from the page buffers if the
 * memory can be used for ddp. Return NULL otherwise.
 */
struct cxgb3i_gather_list *cxgb3i_ddp_make_gl(unsigned int xferlen,
					      struct scatterlist *sgl,
					      unsigned int sgcnt,
					      struct pci_dev *pdev,
					      gfp_t gfp)
{
	struct cxgb3i_gather_list *gl;
	struct scatterlist *sg = sgl;
	struct page *sgpage = sg_page(sg);
	unsigned int sglen = sg->length;
	unsigned int sgoffset = sg->offset;
	unsigned int npages = (xferlen + sgoffset + PAGE_SIZE - 1) >>
			      PAGE_SHIFT;
	int i = 1, j = 0;

	if (xferlen < DDP_THRESHOLD) {
		ddp_log_debug("xfer %u < threshold %u, no ddp.\n",
			      xferlen, DDP_THRESHOLD);
		return NULL;
	}

	gl = kzalloc(sizeof(struct cxgb3i_gather_list) +
		     npages * (sizeof(dma_addr_t) + sizeof(struct page *)),
		     gfp);
	if (!gl)
		return NULL;

	gl->pages = (struct page **)&gl->phys_addr[npages];
	gl->length = xferlen;
	gl->offset = sgoffset;
	gl->pages[0] = sgpage;

	sg = sg_next(sg);
	while (sg) {
		struct page *page = sg_page(sg);

		if (sgpage == page && sg->offset == sgoffset + sglen)
			sglen += sg->length;
		else {
			/* make sure the sgl is fit for ddp:
			 * each has the same page size, and
			 * all of the middle pages are used completely
			 */
			if ((j && sgoffset) ||
			    ((i != sgcnt - 1) &&
			     ((sglen + sgoffset) & ~PAGE_MASK)))
				goto error_out;

			j++;
			if (j == gl->nelem || sg->offset)
				goto error_out;
			gl->pages[j] = page;
			sglen = sg->length;
			sgoffset = sg->offset;
			sgpage = page;
		}
		i++;
		sg = sg_next(sg);
	}
	gl->nelem = ++j;

	if (ddp_gl_map(pdev, gl) < 0)
		goto error_out;

	return gl;

error_out:
	kfree(gl);
	return NULL;
}

/**
 * cxgb3i_ddp_release_gl - release a page buffer list
 * @gl: a ddp page buffer list
 * @pdev: pci_dev used for pci_unmap
 * free a ddp page buffer list resulted from cxgb3i_ddp_make_gl().
 */
void cxgb3i_ddp_release_gl(struct cxgb3i_gather_list *gl,
			   struct pci_dev *pdev)
{
	ddp_gl_unmap(pdev, gl);
	kfree(gl);
}

/**
 * cxgb3i_ddp_tag_reserve - set up ddp for a data transfer
 * @tdev: t3cdev adapter
 * @tid: connection id
 * @tformat: tag format
 * @tagp: contains s/w tag initially, will be updated with ddp/hw tag
 * @gl: the page momory list
 * @gfp: allocation mode
 *
 * ddp setup for a given page buffer list and construct the ddp tag.
 * return 0 if success, < 0 otherwise.
 */
int cxgb3i_ddp_tag_reserve(struct t3cdev *tdev, unsigned int tid,
			   struct cxgb3i_tag_format *tformat, u32 *tagp,
			   struct cxgb3i_gather_list *gl, gfp_t gfp)
{
	struct cxgb3i_ddp_info *ddp = tdev->ulp_iscsi;
	struct pagepod_hdr hdr;
	unsigned int npods;
	int idx = -1;
	int err = -ENOMEM;
	u32 sw_tag = *tagp;
	u32 tag;

	if (page_idx >= DDP_PGIDX_MAX || !ddp || !gl || !gl->nelem ||
		gl->length < DDP_THRESHOLD) {
		ddp_log_debug("pgidx %u, xfer %u/%u, NO ddp.\n",
			      page_idx, gl->length, DDP_THRESHOLD);
		return -EINVAL;
	}

	npods = (gl->nelem + PPOD_PAGES_MAX - 1) >> PPOD_PAGES_SHIFT;

	if (ddp->idx_last == ddp->nppods)
		idx = ddp_find_unused_entries(ddp, 0, ddp->nppods, npods, gl);
	else {
		idx = ddp_find_unused_entries(ddp, ddp->idx_last + 1,
					      ddp->nppods, npods, gl);
		if (idx < 0 && ddp->idx_last >= npods) {
			idx = ddp_find_unused_entries(ddp, 0,
				min(ddp->idx_last + npods, ddp->nppods),
						      npods, gl);
		}
	}
	if (idx < 0) {
		ddp_log_debug("xferlen %u, gl %u, npods %u NO DDP.\n",
			      gl->length, gl->nelem, npods);
		return idx;
	}

	err = ddp_alloc_gl_skb(ddp, idx, npods, gfp);
	if (err < 0)
		goto unmark_entries;

	tag = cxgb3i_ddp_tag_base(tformat, sw_tag);
	tag |= idx << PPOD_IDX_SHIFT;

	hdr.rsvd = 0;
	hdr.vld_tid = htonl(F_PPOD_VALID | V_PPOD_TID(tid));
	hdr.pgsz_tag_clr = htonl(tag & ddp->rsvd_tag_mask);
	hdr.maxoffset = htonl(gl->length);
	hdr.pgoffset = htonl(gl->offset);

	err = set_ddp_map(ddp, &hdr, idx, npods, gl);
	if (err < 0)
		goto free_gl_skb;

	ddp->idx_last = idx;
	ddp_log_debug("xfer %u, gl %u,%u, tid 0x%x, 0x%x -> 0x%x(%u,%u).\n",
		      gl->length, gl->nelem, gl->offset, tid, sw_tag, tag,
		      idx, npods);
	*tagp = tag;
	return 0;

free_gl_skb:
	ddp_free_gl_skb(ddp, idx, npods);
unmark_entries:
	ddp_unmark_entries(ddp, idx, npods);
	return err;
}

/**
 * cxgb3i_ddp_tag_release - release a ddp tag
 * @tdev: t3cdev adapter
 * @tag: ddp tag
 * ddp cleanup for a given ddp tag and release all the resources held
 */
void cxgb3i_ddp_tag_release(struct t3cdev *tdev, u32 tag)
{
	struct cxgb3i_ddp_info *ddp = tdev->ulp_iscsi;
	u32 idx;

	if (!ddp) {
		ddp_log_error("release ddp tag 0x%x, ddp NULL.\n", tag);
		return;
	}

	idx = (tag >> PPOD_IDX_SHIFT) & ddp->idx_mask;
	if (idx < ddp->nppods) {
		struct cxgb3i_gather_list *gl = ddp->gl_map[idx];
		unsigned int npods;

		if (!gl || !gl->nelem) {
			ddp_log_error("release 0x%x, idx 0x%x, gl 0x%p, %u.\n",
				      tag, idx, gl, gl ? gl->nelem : 0);
			return;
		}
		npods = (gl->nelem + PPOD_PAGES_MAX - 1) >> PPOD_PAGES_SHIFT;
		ddp_log_debug("ddp tag 0x%x, release idx 0x%x, npods %u.\n",
			      tag, idx, npods);
		clear_ddp_map(ddp, tag, idx, npods);
		ddp_unmark_entries(ddp, idx, npods);
		cxgb3i_ddp_release_gl(gl, ddp->pdev);
	} else
		ddp_log_error("ddp tag 0x%x, idx 0x%x > max 0x%x.\n",
			      tag, idx, ddp->nppods);
}

static int setup_conn_pgidx(struct t3cdev *tdev, unsigned int tid, int pg_idx,
			    int reply)
{
	struct sk_buff *skb = alloc_skb(sizeof(struct cpl_set_tcb_field),
					GFP_KERNEL);
	struct cpl_set_tcb_field *req;
	u64 val = pg_idx < DDP_PGIDX_MAX ? pg_idx : 0;

	if (!skb)
		return -ENOMEM;

	/* set up ulp submode and page size */
	req = (struct cpl_set_tcb_field *)skb_put(skb, sizeof(*req));
	req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_SET_TCB_FIELD, tid));
	req->reply = V_NO_REPLY(reply ? 0 : 1);
	req->cpu_idx = 0;
	req->word = htons(31);
	req->mask = cpu_to_be64(0xF0000000);
	req->val = cpu_to_be64(val << 28);
	skb->priority = CPL_PRIORITY_CONTROL;

	cxgb3_ofld_send(tdev, skb);
	return 0;
}

/**
 * cxgb3i_setup_conn_host_pagesize - setup the conn.'s ddp page size
 * @tdev: t3cdev adapter
 * @tid: connection id
 * @reply: request reply from h/w
 * set up the ddp page size based on the host PAGE_SIZE for a connection
 * identified by tid
 */
int cxgb3i_setup_conn_host_pagesize(struct t3cdev *tdev, unsigned int tid,
				    int reply)
{
	return setup_conn_pgidx(tdev, tid, page_idx, reply);
}

/**
 * cxgb3i_setup_conn_pagesize - setup the conn.'s ddp page size
 * @tdev: t3cdev adapter
 * @tid: connection id
 * @reply: request reply from h/w
 * @pgsz: ddp page size
 * set up the ddp page size for a connection identified by tid
 */
int cxgb3i_setup_conn_pagesize(struct t3cdev *tdev, unsigned int tid,
				int reply, unsigned long pgsz)
{
	int pgidx = cxgb3i_ddp_find_page_index(pgsz);

	return setup_conn_pgidx(tdev, tid, pgidx, reply);
}

/**
 * cxgb3i_setup_conn_digest - setup conn. digest setting
 * @tdev: t3cdev adapter
 * @tid: connection id
 * @hcrc: header digest enabled
 * @dcrc: data digest enabled
 * @reply: request reply from h/w
 * set up the iscsi digest settings for a connection identified by tid
 */
int cxgb3i_setup_conn_digest(struct t3cdev *tdev, unsigned int tid,
			     int hcrc, int dcrc, int reply)
{
	struct sk_buff *skb = alloc_skb(sizeof(struct cpl_set_tcb_field),
					GFP_KERNEL);
	struct cpl_set_tcb_field *req;
	u64 val = (hcrc ? 1 : 0) | (dcrc ? 2 : 0);

	if (!skb)
		return -ENOMEM;

	/* set up ulp submode and page size */
	req = (struct cpl_set_tcb_field *)skb_put(skb, sizeof(*req));
	req->wr.wr_hi = htonl(V_WR_OP(FW_WROPCODE_FORWARD));
	OPCODE_TID(req) = htonl(MK_OPCODE_TID(CPL_SET_TCB_FIELD, tid));
	req->reply = V_NO_REPLY(reply ? 0 : 1);
	req->cpu_idx = 0;
	req->word = htons(31);
	req->mask = cpu_to_be64(0x0F000000);
	req->val = cpu_to_be64(val << 24);
	skb->priority = CPL_PRIORITY_CONTROL;

	cxgb3_ofld_send(tdev, skb);
	return 0;
}


/**
 * cxgb3i_adapter_ddp_info - read the adapter's ddp information
 * @tdev: t3cdev adapter
 * @tformat: tag format
 * @txsz: max tx pdu payload size, filled in by this func.
 * @rxsz: max rx pdu payload size, filled in by this func.
 * setup the tag format for a given iscsi entity
 */
int cxgb3i_adapter_ddp_info(struct t3cdev *tdev,
			    struct cxgb3i_tag_format *tformat,
			    unsigned int *txsz, unsigned int *rxsz)
{
	struct cxgb3i_ddp_info *ddp;
	unsigned char idx_bits;

	if (!tformat)
		return -EINVAL;

	if (!tdev->ulp_iscsi)
		return -EINVAL;

	ddp = (struct cxgb3i_ddp_info *)tdev->ulp_iscsi;

	idx_bits = 32 - tformat->sw_bits;
	tformat->rsvd_bits = ddp->idx_bits;
	tformat->rsvd_shift = PPOD_IDX_SHIFT;
	tformat->rsvd_mask = (1 << tformat->rsvd_bits) - 1;

	ddp_log_info("tag format: sw %u, rsvd %u,%u, mask 0x%x.\n",
		      tformat->sw_bits, tformat->rsvd_bits,
		      tformat->rsvd_shift, tformat->rsvd_mask);

	*txsz = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
			ddp->max_txsz - ISCSI_PDU_NONPAYLOAD_LEN);
	*rxsz = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
			ddp->max_rxsz - ISCSI_PDU_NONPAYLOAD_LEN);
	ddp_log_info("max payload size: %u/%u, %u/%u.\n",
		     *txsz, ddp->max_txsz, *rxsz, ddp->max_rxsz);
	return 0;
}

/**
 * cxgb3i_ddp_cleanup - release the cxgb3 adapter's ddp resource
 * @tdev: t3cdev adapter
 * release all the resource held by the ddp pagepod manager for a given
 * adapter if needed
 */

static void ddp_cleanup(struct kref *kref)
{
	struct cxgb3i_ddp_info *ddp = container_of(kref,
						struct cxgb3i_ddp_info,
						refcnt);
	int i = 0;

	ddp_log_info("kref release ddp 0x%p, t3dev 0x%p.\n", ddp, ddp->tdev);

	ddp->tdev->ulp_iscsi = NULL;
	while (i < ddp->nppods) {
		struct cxgb3i_gather_list *gl = ddp->gl_map[i];
		if (gl) {
			int npods = (gl->nelem + PPOD_PAGES_MAX - 1)
					>> PPOD_PAGES_SHIFT;
			ddp_log_info("t3dev 0x%p, ddp %d + %d.\n",
					ddp->tdev, i, npods);
			kfree(gl);
			ddp_free_gl_skb(ddp, i, npods);
			i += npods;
		} else
			i++;
	}
	cxgb3i_free_big_mem(ddp);
}

void cxgb3i_ddp_cleanup(struct t3cdev *tdev)
{
	struct cxgb3i_ddp_info *ddp = (struct cxgb3i_ddp_info *)tdev->ulp_iscsi;

	ddp_log_info("t3dev 0x%p, release ddp 0x%p.\n", tdev, ddp);
	if (ddp)
		kref_put(&ddp->refcnt, ddp_cleanup);
}

/**
 * ddp_init - initialize the cxgb3 adapter's ddp resource
 * @tdev: t3cdev adapter
 * initialize the ddp pagepod manager for a given adapter
 */
static void ddp_init(struct t3cdev *tdev)
{
	struct cxgb3i_ddp_info *ddp = tdev->ulp_iscsi;
	struct ulp_iscsi_info uinfo;
	unsigned int ppmax, bits;
	int i, err;

	if (ddp) {
		kref_get(&ddp->refcnt);
		ddp_log_warn("t3dev 0x%p, ddp 0x%p already set up.\n",
				tdev, tdev->ulp_iscsi);
		return;
	}

	err = tdev->ctl(tdev, ULP_ISCSI_GET_PARAMS, &uinfo);
	if (err < 0) {
		ddp_log_error("%s, failed to get iscsi param err=%d.\n",
				 tdev->name, err);
		return;
	}

	ppmax = (uinfo.ulimit - uinfo.llimit + 1) >> PPOD_SIZE_SHIFT;
	bits = __ilog2_u32(ppmax) + 1;
	if (bits > PPOD_IDX_MAX_SIZE)
		bits = PPOD_IDX_MAX_SIZE;
	ppmax = (1 << (bits - 1)) - 1;

	ddp = cxgb3i_alloc_big_mem(sizeof(struct cxgb3i_ddp_info) +
				   ppmax *
					(sizeof(struct cxgb3i_gather_list *) +
					sizeof(struct sk_buff *)),
				   GFP_KERNEL);
	if (!ddp) {
		ddp_log_warn("%s unable to alloc ddp 0x%d, ddp disabled.\n",
			     tdev->name, ppmax);
		return;
	}
	ddp->gl_map = (struct cxgb3i_gather_list **)(ddp + 1);
	ddp->gl_skb = (struct sk_buff **)(((char *)ddp->gl_map) +
					  ppmax *
					  sizeof(struct cxgb3i_gather_list *));
	spin_lock_init(&ddp->map_lock);
	kref_init(&ddp->refcnt);

	ddp->tdev = tdev;
	ddp->pdev = uinfo.pdev;
	ddp->max_txsz = min_t(unsigned int, uinfo.max_txsz, ULP2_MAX_PKT_SIZE);
	ddp->max_rxsz = min_t(unsigned int, uinfo.max_rxsz, ULP2_MAX_PKT_SIZE);
	ddp->llimit = uinfo.llimit;
	ddp->ulimit = uinfo.ulimit;
	ddp->nppods = ppmax;
	ddp->idx_last = ppmax;
	ddp->idx_bits = bits;
	ddp->idx_mask = (1 << bits) - 1;
	ddp->rsvd_tag_mask = (1 << (bits + PPOD_IDX_SHIFT)) - 1;

	uinfo.tagmask = ddp->idx_mask << PPOD_IDX_SHIFT;
	for (i = 0; i < DDP_PGIDX_MAX; i++)
		uinfo.pgsz_factor[i] = ddp_page_order[i];
	uinfo.ulimit = uinfo.llimit + (ppmax << PPOD_SIZE_SHIFT);

	err = tdev->ctl(tdev, ULP_ISCSI_SET_PARAMS, &uinfo);
	if (err < 0) {
		ddp_log_warn("%s unable to set iscsi param err=%d, "
			      "ddp disabled.\n", tdev->name, err);
		goto free_ddp_map;
	}

	tdev->ulp_iscsi = ddp;

	ddp_log_info("tdev 0x%p, nppods %u, bits %u, mask 0x%x,0x%x pkt %u/%u,"
			" %u/%u.\n",
			tdev, ppmax, ddp->idx_bits, ddp->idx_mask,
			ddp->rsvd_tag_mask, ddp->max_txsz, uinfo.max_txsz,
			ddp->max_rxsz, uinfo.max_rxsz);
	return;

free_ddp_map:
	cxgb3i_free_big_mem(ddp);
}

/**
 * cxgb3i_ddp_init - initialize ddp functions
 */
void cxgb3i_ddp_init(struct t3cdev *tdev)
{
	if (page_idx == DDP_PGIDX_MAX) {
		page_idx = cxgb3i_ddp_find_page_index(PAGE_SIZE);

		if (page_idx == DDP_PGIDX_MAX) {
			ddp_log_info("system PAGE_SIZE %lu, update hw.\n",
					PAGE_SIZE);
			if (cxgb3i_ddp_adjust_page_table() < 0) {
				ddp_log_info("PAGE_SIZE %lu, ddp disabled.\n",
						PAGE_SIZE);
				return;
			}
			page_idx = cxgb3i_ddp_find_page_index(PAGE_SIZE);
		}
		ddp_log_info("system PAGE_SIZE %lu, ddp idx %u.\n",
				PAGE_SIZE, page_idx);
	}
	ddp_init(tdev);
}