[SCSI] cxgb3i: Add cxgb3i iSCSI driver.

This patch implements the cxgb3i iscsi connection acceleration for the
open-iscsi initiator.

The cxgb3i driver offers the iscsi PDU based offload:
- digest insertion and verification
- payload direct-placement into host memory buffer.

Signed-off-by: Karen Xie <kxie@chelsio.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 770 insertions, 0 deletions

diff --git a/drivers/scsi/cxgb3i/cxgb3i_ddp.c b/drivers/scsi/cxgb3i/cxgb3i_ddp.c
new file mode 100644
index 00000000000..1a41f04264f
--- /dev/null
+++ b/drivers/scsi/cxgb3i/cxgb3i_ddp.c
@@ -0,0 +1,770 @@
+/*
+ * 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>
+
+/* 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.\n",
+			ppmax, ddp->llimit, ddp->ulimit, ddp->idx_bits,
+			ddp->idx_mask, ddp->rsvd_tag_mask,
+			ddp->max_txsz, ddp->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 pkt size, filled in by this func.
+ * @rxsz: max rx pkt 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 = ddp->max_txsz;
+	*rxsz = ddp->max_rxsz;
+	ddp_log_info("ddp max pkt size: %u, %u.\n",
+		     ddp->max_txsz, 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);