drivers/scsi/cxgb3i/cxgb3i_ddp.c - linux/kernel/git/torvalds/linux - Git at Google

 /*
  * 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 DRV_MODULE_NAME         "cxgb3i_ddp"
 #define DRV_MODULE_VERSION      "1.0.0"
 #define DRV_MODULE_RELDATE      "Dec. 1, 2008"

 static char version[] =
 	"Chelsio S3xx iSCSI DDP " DRV_MODULE_NAME
 	" v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";

 MODULE_AUTHOR("Karen Xie <kxie@chelsio.com>");
 MODULE_DESCRIPTION("cxgb3i ddp pagepod manager");
 MODULE_LICENSE("GPL");
 MODULE_VERSION(DRV_MODULE_VERSION);

 #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;

 static LIST_HEAD(cxgb3i_ddp_list);
 static DEFINE_RWLOCK(cxgb3i_ddp_rwlock);

 /*
  * 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 int clear_ddp_map(struct cxgb3i_ddp_info *ddp, 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];

 		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);
 	}
 	return 0;
 }

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

 	spin_lock(&ddp->map_lock);
 	for (i = start; i <= max;) {
 		for (j = 0; j < count; j++) {
 			if (ddp->gl_map[i + j])
 				break;
 		}
 		if (j == count) {
 			for (j = 0; j < count; j++)
 				ddp->gl_map[i + j] = 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;
 }
 EXPORT_SYMBOL_GPL(cxgb3i_ddp_find_page_index);

 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;
 }
 EXPORT_SYMBOL_GPL(cxgb3i_ddp_make_gl);

 /**
  * 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);
 }
 EXPORT_SYMBOL_GPL(cxgb3i_ddp_release_gl);

 /**
  * cxgb3i_ddp_tag_reserve - set up ddp for a data transfer
  * @tdev: t3cdev adapter
  * @tid: connection id
  * @tformat: tag format
  * @tagp: the s/w tag, if ddp setup is successful, it 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, idx_max;
 	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;
 	idx_max = ddp->nppods - npods + 1;

 	if (ddp->idx_last == ddp->nppods)
 		idx = ddp_find_unused_entries(ddp, 0, idx_max, npods, gl);
 	else {
 		idx = ddp_find_unused_entries(ddp, ddp->idx_last + 1,
 					      idx_max, npods, gl);
 		if (idx < 0 && ddp->idx_last >= npods)
 			idx = ddp_find_unused_entries(ddp, 0,
 						      ddp->idx_last - npods + 1,
 						      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;
 }
 EXPORT_SYMBOL_GPL(cxgb3i_ddp_tag_reserve);

 /**
  * 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) {
 			ddp_log_error("release ddp 0x%x, idx 0x%x, gl NULL.\n",
 				      tag, idx);
 			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, 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);
 }
 EXPORT_SYMBOL_GPL(cxgb3i_ddp_tag_release);

 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);
 }
 EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_host_pagesize);

 /**
  * 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);
 }
 EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_pagesize);

 /**
  * 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;
 }
 EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_digest);

 static int ddp_init(struct t3cdev *tdev)
 {
 	struct cxgb3i_ddp_info *ddp;
 	struct ulp_iscsi_info uinfo;
 	unsigned int ppmax, bits;
 	int i, err;
 	static int vers_printed;

 	if (!vers_printed) {
 		printk(KERN_INFO "%s", version);
 		vers_printed = 1;
 	}

 	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 err;
 	}

 	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 0;
 	}
 	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);

 	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;

 	/* add to the list */
 	write_lock(&cxgb3i_ddp_rwlock);
 	list_add_tail(&ddp->list, &cxgb3i_ddp_list);
 	write_unlock(&cxgb3i_ddp_rwlock);

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

 free_ddp_map:
 	cxgb3i_free_big_mem(ddp);
 	return err;
 }

 /**
  * cxgb3i_adapter_ddp_init - initialize the adapter's ddp resource
  * @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.
  * initialize the ddp pagepod manager for a given adapter if needed and
  * setup the tag format for a given iscsi entity
  */
 int cxgb3i_adapter_ddp_init(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) {
 		int err = ddp_init(tdev);
 		if (err < 0)
 			return err;
 	}
 	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;
 }
 EXPORT_SYMBOL_GPL(cxgb3i_adapter_ddp_init);

 static void ddp_release(struct cxgb3i_ddp_info *ddp)
 {
 	int i = 0;
 	struct t3cdev *tdev = ddp->tdev;

 	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;

 			kfree(gl);
 			ddp_free_gl_skb(ddp, i, npods);
 		} else
 			i++;
 	}
 	cxgb3i_free_big_mem(ddp);
 }

 /**
  * cxgb3i_adapter_ddp_cleanup - release the adapter's ddp resource
  * @tdev: t3cdev adapter
  * release all the resource held by the ddp pagepod manager for a given
  * adapter if needed
  */
 void cxgb3i_adapter_ddp_cleanup(struct t3cdev *tdev)
 {
 	struct cxgb3i_ddp_info *ddp;

 	/* remove from the list */
 	write_lock(&cxgb3i_ddp_rwlock);
 	list_for_each_entry(ddp, &cxgb3i_ddp_list, list) {
 		if (ddp->tdev == tdev) {
 			list_del(&ddp->list);
 			break;
 		}
 	}
 	write_unlock(&cxgb3i_ddp_rwlock);

 	if (ddp)
 		ddp_release(ddp);
 }
 EXPORT_SYMBOL_GPL(cxgb3i_adapter_ddp_cleanup);

 /**
  * cxgb3i_ddp_init_module - module init entry point
  * initialize any driver wide global data structures
  */
 static int __init cxgb3i_ddp_init_module(void)
 {
 	page_idx = cxgb3i_ddp_find_page_index(PAGE_SIZE);
 	ddp_log_info("system PAGE_SIZE %lu, ddp idx %u.\n",
 		     PAGE_SIZE, page_idx);
 	return 0;
 }

 /**
  * cxgb3i_ddp_exit_module - module cleanup/exit entry point
  * go through the ddp list and release any resource held.
  */
 static void __exit cxgb3i_ddp_exit_module(void)
 {
 	struct cxgb3i_ddp_info *ddp;

 	/* release all ddp manager if there is any */
 	write_lock(&cxgb3i_ddp_rwlock);
 	list_for_each_entry(ddp, &cxgb3i_ddp_list, list) {
 		list_del(&ddp->list);
 		ddp_release(ddp);
 	}
 	write_unlock(&cxgb3i_ddp_rwlock);
 }

 module_init(cxgb3i_ddp_init_module);
 module_exit(cxgb3i_ddp_exit_module);
	/*
	* 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 DRV_MODULE_NAME "cxgb3i_ddp"
	#define DRV_MODULE_VERSION "1.0.0"
	#define DRV_MODULE_RELDATE "Dec. 1, 2008"

	static char version[] =
	"Chelsio S3xx iSCSI DDP " DRV_MODULE_NAME
	" v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";

	MODULE_AUTHOR("Karen Xie <kxie@chelsio.com>");
	MODULE_DESCRIPTION("cxgb3i ddp pagepod manager");
	MODULE_LICENSE("GPL");
	MODULE_VERSION(DRV_MODULE_VERSION);

	#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;

	static LIST_HEAD(cxgb3i_ddp_list);
	static DEFINE_RWLOCK(cxgb3i_ddp_rwlock);

	/*
	* 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 int clear_ddp_map(struct cxgb3i_ddp_info *ddp, 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];

	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);
	}
	return 0;
	}

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

	spin_lock(&ddp->map_lock);
	for (i = start; i <= max;) {
	for (j = 0; j < count; j++) {
	if (ddp->gl_map[i + j])
	break;
	}
	if (j == count) {
	for (j = 0; j < count; j++)
	ddp->gl_map[i + j] = 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;
	}
	EXPORT_SYMBOL_GPL(cxgb3i_ddp_find_page_index);

	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;
	}
	EXPORT_SYMBOL_GPL(cxgb3i_ddp_make_gl);

	/**
	* 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);
	}
	EXPORT_SYMBOL_GPL(cxgb3i_ddp_release_gl);

	/**
	* cxgb3i_ddp_tag_reserve - set up ddp for a data transfer
	* @tdev: t3cdev adapter
	* @tid: connection id
	* @tformat: tag format
	* @tagp: the s/w tag, if ddp setup is successful, it 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, idx_max;
	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;
	idx_max = ddp->nppods - npods + 1;

	if (ddp->idx_last == ddp->nppods)
	idx = ddp_find_unused_entries(ddp, 0, idx_max, npods, gl);
	else {
	idx = ddp_find_unused_entries(ddp, ddp->idx_last + 1,
	idx_max, npods, gl);
	if (idx < 0 && ddp->idx_last >= npods)
	idx = ddp_find_unused_entries(ddp, 0,
	ddp->idx_last - npods + 1,
	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;
	}
	EXPORT_SYMBOL_GPL(cxgb3i_ddp_tag_reserve);

	/**
	* 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) {
	ddp_log_error("release ddp 0x%x, idx 0x%x, gl NULL.\n",
	tag, idx);
	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, 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);
	}
	EXPORT_SYMBOL_GPL(cxgb3i_ddp_tag_release);

	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);
	}
	EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_host_pagesize);

	/**
	* 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);
	}
	EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_pagesize);

	/**
	* 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;
	}
	EXPORT_SYMBOL_GPL(cxgb3i_setup_conn_digest);

	static int ddp_init(struct t3cdev *tdev)
	{
	struct cxgb3i_ddp_info *ddp;
	struct ulp_iscsi_info uinfo;
	unsigned int ppmax, bits;
	int i, err;
	static int vers_printed;

	if (!vers_printed) {
	printk(KERN_INFO "%s", version);
	vers_printed = 1;
	}

	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 err;
	}

	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 0;
	}
	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);

	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;

	/* add to the list */
	write_lock(&cxgb3i_ddp_rwlock);
	list_add_tail(&ddp->list, &cxgb3i_ddp_list);
	write_unlock(&cxgb3i_ddp_rwlock);

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

	free_ddp_map:
	cxgb3i_free_big_mem(ddp);
	return err;
	}

	/**
	* cxgb3i_adapter_ddp_init - initialize the adapter's ddp resource
	* @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.
	* initialize the ddp pagepod manager for a given adapter if needed and
	* setup the tag format for a given iscsi entity
	*/
	int cxgb3i_adapter_ddp_init(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) {
	int err = ddp_init(tdev);
	if (err < 0)
	return err;
	}
	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;
	}
	EXPORT_SYMBOL_GPL(cxgb3i_adapter_ddp_init);

	static void ddp_release(struct cxgb3i_ddp_info *ddp)
	{
	int i = 0;
	struct t3cdev *tdev = ddp->tdev;

	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;

	kfree(gl);
	ddp_free_gl_skb(ddp, i, npods);
	} else
	i++;
	}
	cxgb3i_free_big_mem(ddp);
	}

	/**
	* cxgb3i_adapter_ddp_cleanup - release the adapter's ddp resource
	* @tdev: t3cdev adapter
	* release all the resource held by the ddp pagepod manager for a given
	* adapter if needed
	*/
	void cxgb3i_adapter_ddp_cleanup(struct t3cdev *tdev)
	{
	struct cxgb3i_ddp_info *ddp;

	/* remove from the list */
	write_lock(&cxgb3i_ddp_rwlock);
	list_for_each_entry(ddp, &cxgb3i_ddp_list, list) {
	if (ddp->tdev == tdev) {
	list_del(&ddp->list);
	break;
	}
	}
	write_unlock(&cxgb3i_ddp_rwlock);

	if (ddp)
	ddp_release(ddp);
	}
	EXPORT_SYMBOL_GPL(cxgb3i_adapter_ddp_cleanup);

	/**
	* cxgb3i_ddp_init_module - module init entry point
	* initialize any driver wide global data structures
	*/
	static int __init cxgb3i_ddp_init_module(void)
	{
	page_idx = cxgb3i_ddp_find_page_index(PAGE_SIZE);
	ddp_log_info("system PAGE_SIZE %lu, ddp idx %u.\n",
	PAGE_SIZE, page_idx);
	return 0;
	}

	/**
	* cxgb3i_ddp_exit_module - module cleanup/exit entry point
	* go through the ddp list and release any resource held.
	*/
	static void __exit cxgb3i_ddp_exit_module(void)
	{
	struct cxgb3i_ddp_info *ddp;

	/* release all ddp manager if there is any */
	write_lock(&cxgb3i_ddp_rwlock);
	list_for_each_entry(ddp, &cxgb3i_ddp_list, list) {
	list_del(&ddp->list);
	ddp_release(ddp);
	}
	write_unlock(&cxgb3i_ddp_rwlock);
	}

	module_init(cxgb3i_ddp_init_module);
	module_exit(cxgb3i_ddp_exit_module);