IB/ipath: Deprecate ipath driver and move to staging.

It is now time for the ipath driver to begin to be phased out of the kernel.
This patch moves the ipath driver from the Infiniband sub tree to the staging
area where it will remain until the code is removed from the kernel in a few
releases.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 875 insertions, 0 deletions

diff --git a/drivers/staging/rdma/ipath/ipath_user_sdma.c b/drivers/staging/rdma/ipath/ipath_user_sdma.c
new file mode 100644
index 000000000000..cc04b7ba3488
--- /dev/null
+++ b/drivers/staging/rdma/ipath/ipath_user_sdma.c
@@ -0,0 +1,875 @@
+/*
+ * Copyright (c) 2007, 2008 QLogic Corporation. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+#include <linux/mm.h>
+#include <linux/types.h>
+#include <linux/device.h>
+#include <linux/dmapool.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+#include <linux/highmem.h>
+#include <linux/io.h>
+#include <linux/uio.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+
+#include "ipath_kernel.h"
+#include "ipath_user_sdma.h"
+
+/* minimum size of header */
+#define IPATH_USER_SDMA_MIN_HEADER_LENGTH	64
+/* expected size of headers (for dma_pool) */
+#define IPATH_USER_SDMA_EXP_HEADER_LENGTH	64
+/* length mask in PBC (lower 11 bits) */
+#define IPATH_PBC_LENGTH_MASK			((1 << 11) - 1)
+
+struct ipath_user_sdma_pkt {
+	u8 naddr;		/* dimension of addr (1..3) ... */
+	u32 counter;		/* sdma pkts queued counter for this entry */
+	u64 added;		/* global descq number of entries */
+
+	struct {
+		u32 offset;			/* offset for kvaddr, addr */
+		u32 length;			/* length in page */
+		u8  put_page;			/* should we put_page? */
+		u8  dma_mapped;			/* is page dma_mapped? */
+		struct page *page;		/* may be NULL (coherent mem) */
+		void *kvaddr;			/* FIXME: only for pio hack */
+		dma_addr_t addr;
+	} addr[4];   /* max pages, any more and we coalesce */
+	struct list_head list;	/* list element */
+};
+
+struct ipath_user_sdma_queue {
+	/*
+	 * pkts sent to dma engine are queued on this
+	 * list head.  the type of the elements of this
+	 * list are struct ipath_user_sdma_pkt...
+	 */
+	struct list_head sent;
+
+	/* headers with expected length are allocated from here... */
+	char header_cache_name[64];
+	struct dma_pool *header_cache;
+
+	/* packets are allocated from the slab cache... */
+	char pkt_slab_name[64];
+	struct kmem_cache *pkt_slab;
+
+	/* as packets go on the queued queue, they are counted... */
+	u32 counter;
+	u32 sent_counter;
+
+	/* dma page table */
+	struct rb_root dma_pages_root;
+
+	/* protect everything above... */
+	struct mutex lock;
+};
+
+struct ipath_user_sdma_queue *
+ipath_user_sdma_queue_create(struct device *dev, int unit, int port, int sport)
+{
+	struct ipath_user_sdma_queue *pq =
+		kmalloc(sizeof(struct ipath_user_sdma_queue), GFP_KERNEL);
+
+	if (!pq)
+		goto done;
+
+	pq->counter = 0;
+	pq->sent_counter = 0;
+	INIT_LIST_HEAD(&pq->sent);
+
+	mutex_init(&pq->lock);
+
+	snprintf(pq->pkt_slab_name, sizeof(pq->pkt_slab_name),
+		 "ipath-user-sdma-pkts-%u-%02u.%02u", unit, port, sport);
+	pq->pkt_slab = kmem_cache_create(pq->pkt_slab_name,
+					 sizeof(struct ipath_user_sdma_pkt),
+					 0, 0, NULL);
+
+	if (!pq->pkt_slab)
+		goto err_kfree;
+
+	snprintf(pq->header_cache_name, sizeof(pq->header_cache_name),
+		 "ipath-user-sdma-headers-%u-%02u.%02u", unit, port, sport);
+	pq->header_cache = dma_pool_create(pq->header_cache_name,
+					   dev,
+					   IPATH_USER_SDMA_EXP_HEADER_LENGTH,
+					   4, 0);
+	if (!pq->header_cache)
+		goto err_slab;
+
+	pq->dma_pages_root = RB_ROOT;
+
+	goto done;
+
+err_slab:
+	kmem_cache_destroy(pq->pkt_slab);
+err_kfree:
+	kfree(pq);
+	pq = NULL;
+
+done:
+	return pq;
+}
+
+static void ipath_user_sdma_init_frag(struct ipath_user_sdma_pkt *pkt,
+				      int i, size_t offset, size_t len,
+				      int put_page, int dma_mapped,
+				      struct page *page,
+				      void *kvaddr, dma_addr_t dma_addr)
+{
+	pkt->addr[i].offset = offset;
+	pkt->addr[i].length = len;
+	pkt->addr[i].put_page = put_page;
+	pkt->addr[i].dma_mapped = dma_mapped;
+	pkt->addr[i].page = page;
+	pkt->addr[i].kvaddr = kvaddr;
+	pkt->addr[i].addr = dma_addr;
+}
+
+static void ipath_user_sdma_init_header(struct ipath_user_sdma_pkt *pkt,
+					u32 counter, size_t offset,
+					size_t len, int dma_mapped,
+					struct page *page,
+					void *kvaddr, dma_addr_t dma_addr)
+{
+	pkt->naddr = 1;
+	pkt->counter = counter;
+	ipath_user_sdma_init_frag(pkt, 0, offset, len, 0, dma_mapped, page,
+				  kvaddr, dma_addr);
+}
+
+/* we've too many pages in the iovec, coalesce to a single page */
+static int ipath_user_sdma_coalesce(const struct ipath_devdata *dd,
+				    struct ipath_user_sdma_pkt *pkt,
+				    const struct iovec *iov,
+				    unsigned long niov) {
+	int ret = 0;
+	struct page *page = alloc_page(GFP_KERNEL);
+	void *mpage_save;
+	char *mpage;
+	int i;
+	int len = 0;
+	dma_addr_t dma_addr;
+
+	if (!page) {
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	mpage = kmap(page);
+	mpage_save = mpage;
+	for (i = 0; i < niov; i++) {
+		int cfur;
+
+		cfur = copy_from_user(mpage,
+				      iov[i].iov_base, iov[i].iov_len);
+		if (cfur) {
+			ret = -EFAULT;
+			goto free_unmap;
+		}
+
+		mpage += iov[i].iov_len;
+		len += iov[i].iov_len;
+	}
+
+	dma_addr = dma_map_page(&dd->pcidev->dev, page, 0, len,
+				DMA_TO_DEVICE);
+	if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+		ret = -ENOMEM;
+		goto free_unmap;
+	}
+
+	ipath_user_sdma_init_frag(pkt, 1, 0, len, 0, 1, page, mpage_save,
+				  dma_addr);
+	pkt->naddr = 2;
+
+	goto done;
+
+free_unmap:
+	kunmap(page);
+	__free_page(page);
+done:
+	return ret;
+}
+
+/* how many pages in this iovec element? */
+static int ipath_user_sdma_num_pages(const struct iovec *iov)
+{
+	const unsigned long addr  = (unsigned long) iov->iov_base;
+	const unsigned long  len  = iov->iov_len;
+	const unsigned long spage = addr & PAGE_MASK;
+	const unsigned long epage = (addr + len - 1) & PAGE_MASK;
+
+	return 1 + ((epage - spage) >> PAGE_SHIFT);
+}
+
+/* truncate length to page boundary */
+static int ipath_user_sdma_page_length(unsigned long addr, unsigned long len)
+{
+	const unsigned long offset = addr & ~PAGE_MASK;
+
+	return ((offset + len) > PAGE_SIZE) ? (PAGE_SIZE - offset) : len;
+}
+
+static void ipath_user_sdma_free_pkt_frag(struct device *dev,
+					  struct ipath_user_sdma_queue *pq,
+					  struct ipath_user_sdma_pkt *pkt,
+					  int frag)
+{
+	const int i = frag;
+
+	if (pkt->addr[i].page) {
+		if (pkt->addr[i].dma_mapped)
+			dma_unmap_page(dev,
+				       pkt->addr[i].addr,
+				       pkt->addr[i].length,
+				       DMA_TO_DEVICE);
+
+		if (pkt->addr[i].kvaddr)
+			kunmap(pkt->addr[i].page);
+
+		if (pkt->addr[i].put_page)
+			put_page(pkt->addr[i].page);
+		else
+			__free_page(pkt->addr[i].page);
+	} else if (pkt->addr[i].kvaddr)
+		/* free coherent mem from cache... */
+		dma_pool_free(pq->header_cache,
+			      pkt->addr[i].kvaddr, pkt->addr[i].addr);
+}
+
+/* return number of pages pinned... */
+static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd,
+				     struct ipath_user_sdma_pkt *pkt,
+				     unsigned long addr, int tlen, int npages)
+{
+	struct page *pages[2];
+	int j;
+	int ret;
+
+	ret = get_user_pages_fast(addr, npages, 0, pages);
+	if (ret != npages) {
+		int i;
+
+		for (i = 0; i < ret; i++)
+			put_page(pages[i]);
+
+		ret = -ENOMEM;
+		goto done;
+	}
+
+	for (j = 0; j < npages; j++) {
+		/* map the pages... */
+		const int flen =
+			ipath_user_sdma_page_length(addr, tlen);
+		dma_addr_t dma_addr =
+			dma_map_page(&dd->pcidev->dev,
+				     pages[j], 0, flen, DMA_TO_DEVICE);
+		unsigned long fofs = addr & ~PAGE_MASK;
+
+		if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+			ret = -ENOMEM;
+			goto done;
+		}
+
+		ipath_user_sdma_init_frag(pkt, pkt->naddr, fofs, flen, 1, 1,
+					  pages[j], kmap(pages[j]),
+					  dma_addr);
+
+		pkt->naddr++;
+		addr += flen;
+		tlen -= flen;
+	}
+
+done:
+	return ret;
+}
+
+static int ipath_user_sdma_pin_pkt(const struct ipath_devdata *dd,
+				   struct ipath_user_sdma_queue *pq,
+				   struct ipath_user_sdma_pkt *pkt,
+				   const struct iovec *iov,
+				   unsigned long niov)
+{
+	int ret = 0;
+	unsigned long idx;
+
+	for (idx = 0; idx < niov; idx++) {
+		const int npages = ipath_user_sdma_num_pages(iov + idx);
+		const unsigned long addr = (unsigned long) iov[idx].iov_base;
+
+		ret = ipath_user_sdma_pin_pages(dd, pkt,
+						addr, iov[idx].iov_len,
+						npages);
+		if (ret < 0)
+			goto free_pkt;
+	}
+
+	goto done;
+
+free_pkt:
+	for (idx = 0; idx < pkt->naddr; idx++)
+		ipath_user_sdma_free_pkt_frag(&dd->pcidev->dev, pq, pkt, idx);
+
+done:
+	return ret;
+}
+
+static int ipath_user_sdma_init_payload(const struct ipath_devdata *dd,
+					struct ipath_user_sdma_queue *pq,
+					struct ipath_user_sdma_pkt *pkt,
+					const struct iovec *iov,
+					unsigned long niov, int npages)
+{
+	int ret = 0;
+
+	if (npages >= ARRAY_SIZE(pkt->addr))
+		ret = ipath_user_sdma_coalesce(dd, pkt, iov, niov);
+	else
+		ret = ipath_user_sdma_pin_pkt(dd, pq, pkt, iov, niov);
+
+	return ret;
+}
+
+/* free a packet list -- return counter value of last packet */
+static void ipath_user_sdma_free_pkt_list(struct device *dev,
+					  struct ipath_user_sdma_queue *pq,
+					  struct list_head *list)
+{
+	struct ipath_user_sdma_pkt *pkt, *pkt_next;
+
+	list_for_each_entry_safe(pkt, pkt_next, list, list) {
+		int i;
+
+		for (i = 0; i < pkt->naddr; i++)
+			ipath_user_sdma_free_pkt_frag(dev, pq, pkt, i);
+
+		kmem_cache_free(pq->pkt_slab, pkt);
+	}
+}
+
+/*
+ * copy headers, coalesce etc -- pq->lock must be held
+ *
+ * we queue all the packets to list, returning the
+ * number of bytes total.  list must be empty initially,
+ * as, if there is an error we clean it...
+ */
+static int ipath_user_sdma_queue_pkts(const struct ipath_devdata *dd,
+				      struct ipath_user_sdma_queue *pq,
+				      struct list_head *list,
+				      const struct iovec *iov,
+				      unsigned long niov,
+				      int maxpkts)
+{
+	unsigned long idx = 0;
+	int ret = 0;
+	int npkts = 0;
+	struct page *page = NULL;
+	__le32 *pbc;
+	dma_addr_t dma_addr;
+	struct ipath_user_sdma_pkt *pkt = NULL;
+	size_t len;
+	size_t nw;
+	u32 counter = pq->counter;
+	int dma_mapped = 0;
+
+	while (idx < niov && npkts < maxpkts) {
+		const unsigned long addr = (unsigned long) iov[idx].iov_base;
+		const unsigned long idx_save = idx;
+		unsigned pktnw;
+		unsigned pktnwc;
+		int nfrags = 0;
+		int npages = 0;
+		int cfur;
+
+		dma_mapped = 0;
+		len = iov[idx].iov_len;
+		nw = len >> 2;
+		page = NULL;
+
+		pkt = kmem_cache_alloc(pq->pkt_slab, GFP_KERNEL);
+		if (!pkt) {
+			ret = -ENOMEM;
+			goto free_list;
+		}
+
+		if (len < IPATH_USER_SDMA_MIN_HEADER_LENGTH ||
+		    len > PAGE_SIZE || len & 3 || addr & 3) {
+			ret = -EINVAL;
+			goto free_pkt;
+		}
+
+		if (len == IPATH_USER_SDMA_EXP_HEADER_LENGTH)
+			pbc = dma_pool_alloc(pq->header_cache, GFP_KERNEL,
+					     &dma_addr);
+		else
+			pbc = NULL;
+
+		if (!pbc) {
+			page = alloc_page(GFP_KERNEL);
+			if (!page) {
+				ret = -ENOMEM;
+				goto free_pkt;
+			}
+			pbc = kmap(page);
+		}
+
+		cfur = copy_from_user(pbc, iov[idx].iov_base, len);
+		if (cfur) {
+			ret = -EFAULT;
+			goto free_pbc;
+		}
+
+		/*
+		 * this assignment is a bit strange.  it's because the
+		 * the pbc counts the number of 32 bit words in the full
+		 * packet _except_ the first word of the pbc itself...
+		 */
+		pktnwc = nw - 1;
+
+		/*
+		 * pktnw computation yields the number of 32 bit words
+		 * that the caller has indicated in the PBC.  note that
+		 * this is one less than the total number of words that
+		 * goes to the send DMA engine as the first 32 bit word
+		 * of the PBC itself is not counted.  Armed with this count,
+		 * we can verify that the packet is consistent with the
+		 * iovec lengths.
+		 */
+		pktnw = le32_to_cpu(*pbc) & IPATH_PBC_LENGTH_MASK;
+		if (pktnw < pktnwc || pktnw > pktnwc + (PAGE_SIZE >> 2)) {
+			ret = -EINVAL;
+			goto free_pbc;
+		}
+
+
+		idx++;
+		while (pktnwc < pktnw && idx < niov) {
+			const size_t slen = iov[idx].iov_len;
+			const unsigned long faddr =
+				(unsigned long) iov[idx].iov_base;
+
+			if (slen & 3 || faddr & 3 || !slen ||
+			    slen > PAGE_SIZE) {
+				ret = -EINVAL;
+				goto free_pbc;
+			}
+
+			npages++;
+			if ((faddr & PAGE_MASK) !=
+			    ((faddr + slen - 1) & PAGE_MASK))
+				npages++;
+
+			pktnwc += slen >> 2;
+			idx++;
+			nfrags++;
+		}
+
+		if (pktnwc != pktnw) {
+			ret = -EINVAL;
+			goto free_pbc;
+		}
+
+		if (page) {
+			dma_addr = dma_map_page(&dd->pcidev->dev,
+						page, 0, len, DMA_TO_DEVICE);
+			if (dma_mapping_error(&dd->pcidev->dev, dma_addr)) {
+				ret = -ENOMEM;
+				goto free_pbc;
+			}
+
+			dma_mapped = 1;
+		}
+
+		ipath_user_sdma_init_header(pkt, counter, 0, len, dma_mapped,
+					    page, pbc, dma_addr);
+
+		if (nfrags) {
+			ret = ipath_user_sdma_init_payload(dd, pq, pkt,
+							   iov + idx_save + 1,
+							   nfrags, npages);
+			if (ret < 0)
+				goto free_pbc_dma;
+		}
+
+		counter++;
+		npkts++;
+
+		list_add_tail(&pkt->list, list);
+	}
+
+	ret = idx;
+	goto done;
+
+free_pbc_dma:
+	if (dma_mapped)
+		dma_unmap_page(&dd->pcidev->dev, dma_addr, len, DMA_TO_DEVICE);
+free_pbc:
+	if (page) {
+		kunmap(page);
+		__free_page(page);
+	} else
+		dma_pool_free(pq->header_cache, pbc, dma_addr);
+free_pkt:
+	kmem_cache_free(pq->pkt_slab, pkt);
+free_list:
+	ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, list);
+done:
+	return ret;
+}
+
+static void ipath_user_sdma_set_complete_counter(struct ipath_user_sdma_queue *pq,
+						 u32 c)
+{
+	pq->sent_counter = c;
+}
+
+/* try to clean out queue -- needs pq->lock */
+static int ipath_user_sdma_queue_clean(const struct ipath_devdata *dd,
+				       struct ipath_user_sdma_queue *pq)
+{
+	struct list_head free_list;
+	struct ipath_user_sdma_pkt *pkt;
+	struct ipath_user_sdma_pkt *pkt_prev;
+	int ret = 0;
+
+	INIT_LIST_HEAD(&free_list);
+
+	list_for_each_entry_safe(pkt, pkt_prev, &pq->sent, list) {
+		s64 descd = dd->ipath_sdma_descq_removed - pkt->added;
+
+		if (descd < 0)
+			break;
+
+		list_move_tail(&pkt->list, &free_list);
+
+		/* one more packet cleaned */
+		ret++;
+	}
+
+	if (!list_empty(&free_list)) {
+		u32 counter;
+
+		pkt = list_entry(free_list.prev,
+				 struct ipath_user_sdma_pkt, list);
+		counter = pkt->counter;
+
+		ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
+		ipath_user_sdma_set_complete_counter(pq, counter);
+	}
+
+	return ret;
+}
+
+void ipath_user_sdma_queue_destroy(struct ipath_user_sdma_queue *pq)
+{
+	if (!pq)
+		return;
+
+	kmem_cache_destroy(pq->pkt_slab);
+	dma_pool_destroy(pq->header_cache);
+	kfree(pq);
+}
+
+/* clean descriptor queue, returns > 0 if some elements cleaned */
+static int ipath_user_sdma_hwqueue_clean(struct ipath_devdata *dd)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dd->ipath_sdma_lock, flags);
+	ret = ipath_sdma_make_progress(dd);
+	spin_unlock_irqrestore(&dd->ipath_sdma_lock, flags);
+
+	return ret;
+}
+
+/* we're in close, drain packets so that we can cleanup successfully... */
+void ipath_user_sdma_queue_drain(struct ipath_devdata *dd,
+				 struct ipath_user_sdma_queue *pq)
+{
+	int i;
+
+	if (!pq)
+		return;
+
+	for (i = 0; i < 100; i++) {
+		mutex_lock(&pq->lock);
+		if (list_empty(&pq->sent)) {
+			mutex_unlock(&pq->lock);
+			break;
+		}
+		ipath_user_sdma_hwqueue_clean(dd);
+		ipath_user_sdma_queue_clean(dd, pq);
+		mutex_unlock(&pq->lock);
+		msleep(10);
+	}
+
+	if (!list_empty(&pq->sent)) {
+		struct list_head free_list;
+
+		printk(KERN_INFO "drain: lists not empty: forcing!\n");
+		INIT_LIST_HEAD(&free_list);
+		mutex_lock(&pq->lock);
+		list_splice_init(&pq->sent, &free_list);
+		ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);
+		mutex_unlock(&pq->lock);
+	}
+}
+
+static inline __le64 ipath_sdma_make_desc0(struct ipath_devdata *dd,
+					   u64 addr, u64 dwlen, u64 dwoffset)
+{
+	return cpu_to_le64(/* SDmaPhyAddr[31:0] */
+			   ((addr & 0xfffffffcULL) << 32) |
+			   /* SDmaGeneration[1:0] */
+			   ((dd->ipath_sdma_generation & 3ULL) << 30) |
+			   /* SDmaDwordCount[10:0] */
+			   ((dwlen & 0x7ffULL) << 16) |
+			   /* SDmaBufOffset[12:2] */
+			   (dwoffset & 0x7ffULL));
+}
+
+static inline __le64 ipath_sdma_make_first_desc0(__le64 descq)
+{
+	return descq | cpu_to_le64(1ULL << 12);
+}
+
+static inline __le64 ipath_sdma_make_last_desc0(__le64 descq)
+{
+					      /* last */  /* dma head */
+	return descq | cpu_to_le64(1ULL << 11 | 1ULL << 13);
+}
+
+static inline __le64 ipath_sdma_make_desc1(u64 addr)
+{
+	/* SDmaPhyAddr[47:32] */
+	return cpu_to_le64(addr >> 32);
+}
+
+static void ipath_user_sdma_send_frag(struct ipath_devdata *dd,
+				      struct ipath_user_sdma_pkt *pkt, int idx,
+				      unsigned ofs, u16 tail)
+{
+	const u64 addr = (u64) pkt->addr[idx].addr +
+		(u64) pkt->addr[idx].offset;
+	const u64 dwlen = (u64) pkt->addr[idx].length / 4;
+	__le64 *descqp;
+	__le64 descq0;
+
+	descqp = &dd->ipath_sdma_descq[tail].qw[0];
+
+	descq0 = ipath_sdma_make_desc0(dd, addr, dwlen, ofs);
+	if (idx == 0)
+		descq0 = ipath_sdma_make_first_desc0(descq0);
+	if (idx == pkt->naddr - 1)
+		descq0 = ipath_sdma_make_last_desc0(descq0);
+
+	descqp[0] = descq0;
+	descqp[1] = ipath_sdma_make_desc1(addr);
+}
+
+/* pq->lock must be held, get packets on the wire... */
+static int ipath_user_sdma_push_pkts(struct ipath_devdata *dd,
+				     struct ipath_user_sdma_queue *pq,
+				     struct list_head *pktlist)
+{
+	int ret = 0;
+	unsigned long flags;
+	u16 tail;
+
+	if (list_empty(pktlist))
+		return 0;
+
+	if (unlikely(!(dd->ipath_flags & IPATH_LINKACTIVE)))
+		return -ECOMM;
+
+	spin_lock_irqsave(&dd->ipath_sdma_lock, flags);
+
+	if (unlikely(dd->ipath_sdma_status & IPATH_SDMA_ABORT_MASK)) {
+		ret = -ECOMM;
+		goto unlock;
+	}
+
+	tail = dd->ipath_sdma_descq_tail;
+	while (!list_empty(pktlist)) {
+		struct ipath_user_sdma_pkt *pkt =
+			list_entry(pktlist->next, struct ipath_user_sdma_pkt,
+				   list);
+		int i;
+		unsigned ofs = 0;
+		u16 dtail = tail;
+
+		if (pkt->naddr > ipath_sdma_descq_freecnt(dd))
+			goto unlock_check_tail;
+
+		for (i = 0; i < pkt->naddr; i++) {
+			ipath_user_sdma_send_frag(dd, pkt, i, ofs, tail);
+			ofs += pkt->addr[i].length >> 2;
+
+			if (++tail == dd->ipath_sdma_descq_cnt) {
+				tail = 0;
+				++dd->ipath_sdma_generation;
+			}
+		}
+
+		if ((ofs<<2) > dd->ipath_ibmaxlen) {
+			ipath_dbg("packet size %X > ibmax %X, fail\n",
+				ofs<<2, dd->ipath_ibmaxlen);
+			ret = -EMSGSIZE;
+			goto unlock;
+		}
+
+		/*
+		 * if the packet is >= 2KB mtu equivalent, we have to use
+		 * the large buffers, and have to mark each descriptor as
+		 * part of a large buffer packet.
+		 */
+		if (ofs >= IPATH_SMALLBUF_DWORDS) {
+			for (i = 0; i < pkt->naddr; i++) {
+				dd->ipath_sdma_descq[dtail].qw[0] |=
+					cpu_to_le64(1ULL << 14);
+				if (++dtail == dd->ipath_sdma_descq_cnt)
+					dtail = 0;
+			}
+		}
+
+		dd->ipath_sdma_descq_added += pkt->naddr;
+		pkt->added = dd->ipath_sdma_descq_added;
+		list_move_tail(&pkt->list, &pq->sent);
+		ret++;
+	}
+
+unlock_check_tail:
+	/* advance the tail on the chip if necessary */
+	if (dd->ipath_sdma_descq_tail != tail) {
+		wmb();
+		ipath_write_kreg(dd, dd->ipath_kregs->kr_senddmatail, tail);
+		dd->ipath_sdma_descq_tail = tail;
+	}
+
+unlock:
+	spin_unlock_irqrestore(&dd->ipath_sdma_lock, flags);
+
+	return ret;
+}
+
+int ipath_user_sdma_writev(struct ipath_devdata *dd,
+			   struct ipath_user_sdma_queue *pq,
+			   const struct iovec *iov,
+			   unsigned long dim)
+{
+	int ret = 0;
+	struct list_head list;
+	int npkts = 0;
+
+	INIT_LIST_HEAD(&list);
+
+	mutex_lock(&pq->lock);
+
+	if (dd->ipath_sdma_descq_added != dd->ipath_sdma_descq_removed) {
+		ipath_user_sdma_hwqueue_clean(dd);
+		ipath_user_sdma_queue_clean(dd, pq);
+	}
+
+	while (dim) {
+		const int mxp = 8;
+
+		ret = ipath_user_sdma_queue_pkts(dd, pq, &list, iov, dim, mxp);
+		if (ret <= 0)
+			goto done_unlock;
+		else {
+			dim -= ret;
+			iov += ret;
+		}
+
+		/* force packets onto the sdma hw queue... */
+		if (!list_empty(&list)) {
+			/*
+			 * lazily clean hw queue.  the 4 is a guess of about
+			 * how many sdma descriptors a packet will take (it
+			 * doesn't have to be perfect).
+			 */
+			if (ipath_sdma_descq_freecnt(dd) < ret * 4) {
+				ipath_user_sdma_hwqueue_clean(dd);
+				ipath_user_sdma_queue_clean(dd, pq);
+			}
+
+			ret = ipath_user_sdma_push_pkts(dd, pq, &list);
+			if (ret < 0)
+				goto done_unlock;
+			else {
+				npkts += ret;
+				pq->counter += ret;
+
+				if (!list_empty(&list))
+					goto done_unlock;
+			}
+		}
+	}
+
+done_unlock:
+	if (!list_empty(&list))
+		ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &list);
+	mutex_unlock(&pq->lock);
+
+	return (ret < 0) ? ret : npkts;
+}
+
+int ipath_user_sdma_make_progress(struct ipath_devdata *dd,
+				  struct ipath_user_sdma_queue *pq)
+{
+	int ret = 0;
+
+	mutex_lock(&pq->lock);
+	ipath_user_sdma_hwqueue_clean(dd);
+	ret = ipath_user_sdma_queue_clean(dd, pq);
+	mutex_unlock(&pq->lock);
+
+	return ret;
+}
+
+u32 ipath_user_sdma_complete_counter(const struct ipath_user_sdma_queue *pq)
+{
+	return pq->sent_counter;
+}
+
+u32 ipath_user_sdma_inflight_counter(struct ipath_user_sdma_queue *pq)
+{
+	return pq->counter;
+}
+