dmaengine: ioatdma: move dma prep functions to single location

Move all DMA descriptor prepping functions to prep.c file. Fixup all
broken bits caused by the move.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

6 files changed, 769 insertions, 749 deletions

diff --git a/drivers/dma/ioat/Makefile b/drivers/dma/ioat/Makefile
index f785f8f42f7d..3a7e66464d0c 100644
--- a/drivers/dma/ioat/Makefile
+++ b/drivers/dma/ioat/Makefile
@@ -1,2 +1,2 @@
 obj-$(CONFIG_INTEL_IOATDMA) += ioatdma.o
-ioatdma-y := init.o dma.o dma_v3.o dca.o sysfs.o
+ioatdma-y := init.o dma.o dma_v3.o prep.o dca.o sysfs.o
diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 5d78cafdd3f2..e67eda055ea5 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -578,50 +578,3 @@ int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)
 
 	return -ENOMEM;
 }
-
-struct dma_async_tx_descriptor *
-ioat_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
-			   dma_addr_t dma_src, size_t len, unsigned long flags)
-{
-	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
-	struct ioat_dma_descriptor *hw;
-	struct ioat_ring_ent *desc;
-	dma_addr_t dst = dma_dest;
-	dma_addr_t src = dma_src;
-	size_t total_len = len;
-	int num_descs, idx, i;
-
-	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
-	if (likely(num_descs) &&
-	    ioat_check_space_lock(ioat_chan, num_descs) == 0)
-		idx = ioat_chan->head;
-	else
-		return NULL;
-	i = 0;
-	do {
-		size_t copy = min_t(size_t, len, 1 << ioat_chan->xfercap_log);
-
-		desc = ioat_get_ring_ent(ioat_chan, idx + i);
-		hw = desc->hw;
-
-		hw->size = copy;
-		hw->ctl = 0;
-		hw->src_addr = src;
-		hw->dst_addr = dst;
-
-		len -= copy;
-		dst += copy;
-		src += copy;
-		dump_desc_dbg(ioat_chan, desc);
-	} while (++i < num_descs);
-
-	desc->txd.flags = flags;
-	desc->len = total_len;
-	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
-	hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
-	hw->ctl_f.compl_write = 1;
-	dump_desc_dbg(ioat_chan, desc);
-	/* we leave the channel locked to ensure in order submission */
-
-	return &desc->txd;
-}
diff --git a/drivers/dma/ioat/dma.h b/drivers/dma/ioat/dma.h
index d2ffa5775d53..a319befad1a3 100644
--- a/drivers/dma/ioat/dma.h
+++ b/drivers/dma/ioat/dma.h
@@ -37,6 +37,14 @@
 
 #define chan_num(ch) ((int)((ch)->reg_base - (ch)->ioat_dma->reg_base) / 0x80)
 
+/* ioat hardware assumes at least two sources for raid operations */
+#define src_cnt_to_sw(x) ((x) + 2)
+#define src_cnt_to_hw(x) ((x) - 2)
+#define ndest_to_sw(x) ((x) + 1)
+#define ndest_to_hw(x) ((x) - 1)
+#define src16_cnt_to_sw(x) ((x) + 9)
+#define src16_cnt_to_hw(x) ((x) - 9)
+
 /*
  * workaround for IOAT ver.3.0 null descriptor issue
  * (channel returns error when size is 0)
@@ -190,15 +198,22 @@ struct ioat_ring_ent {
 	struct ioat_sed_ent *sed;
 };
 
+extern const struct sysfs_ops ioat_sysfs_ops;
+extern struct ioat_sysfs_entry ioat_version_attr;
+extern struct ioat_sysfs_entry ioat_cap_attr;
+extern int ioat_pending_level;
+extern int ioat_ring_alloc_order;
+extern struct kobj_type ioat_ktype;
+extern struct kmem_cache *ioat_cache;
+extern int ioat_ring_max_alloc_order;
+extern struct kmem_cache *ioat_sed_cache;
+
 static inline struct ioatdma_chan *to_ioat_chan(struct dma_chan *c)
 {
 	return container_of(c, struct ioatdma_chan, dma_chan);
 }
 
-
-
 /* wrapper around hardware descriptor format + additional software fields */
-
 #ifdef DEBUG
 #define set_desc_id(desc, i) ((desc)->id = (i))
 #define desc_id(desc) ((desc)->id)
@@ -381,13 +396,10 @@ ioat_set_chainaddr(struct ioatdma_chan *ioat_chan, u64 addr)
 	       ioat_chan->reg_base + IOAT2_CHAINADDR_OFFSET_HIGH);
 }
 
-irqreturn_t ioat_dma_do_interrupt(int irq, void *data);
-irqreturn_t ioat_dma_do_interrupt_msix(int irq, void *data);
-struct ioat_ring_ent **
-ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags);
-void ioat_start_null_desc(struct ioatdma_chan *ioat_chan);
-void ioat_free_ring_ent(struct ioat_ring_ent *desc, struct dma_chan *chan);
-int ioat_reset_hw(struct ioatdma_chan *ioat_chan);
+/* IOAT Prep functions */
+struct dma_async_tx_descriptor *
+ioat_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
+			   dma_addr_t dma_src, size_t len, unsigned long flags);
 struct dma_async_tx_descriptor *
 ioat_prep_interrupt_lock(struct dma_chan *c, unsigned long flags);
 struct dma_async_tx_descriptor *
@@ -412,53 +424,38 @@ struct dma_async_tx_descriptor *
 ioat_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
 		     unsigned int src_cnt, size_t len,
 		     enum sum_check_flags *result, unsigned long flags);
+
+/* IOAT Operation functions */
+irqreturn_t ioat_dma_do_interrupt(int irq, void *data);
+irqreturn_t ioat_dma_do_interrupt_msix(int irq, void *data);
+struct ioat_ring_ent **
+ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags);
+void ioat_start_null_desc(struct ioatdma_chan *ioat_chan);
+void ioat_free_ring_ent(struct ioat_ring_ent *desc, struct dma_chan *chan);
+int ioat_reset_hw(struct ioatdma_chan *ioat_chan);
 enum dma_status
 ioat_tx_status(struct dma_chan *c, dma_cookie_t cookie,
 		struct dma_tx_state *txstate);
 void ioat_cleanup_event(unsigned long data);
 void ioat_timer_event(unsigned long data);
-bool is_bwd_ioat(struct pci_dev *pdev);
-int ioat_probe(struct ioatdma_device *ioat_dma);
-int ioat_register(struct ioatdma_device *ioat_dma);
-int ioat_dma_self_test(struct ioatdma_device *ioat_dma);
-void ioat_dma_remove(struct ioatdma_device *ioat_dma);
-struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase);
-void ioat_init_channel(struct ioatdma_device *ioat_dma,
-		       struct ioatdma_chan *ioat_chan, int idx);
 enum dma_status ioat_dma_tx_status(struct dma_chan *c, dma_cookie_t cookie,
 				   struct dma_tx_state *txstate);
 bool ioat_cleanup_preamble(struct ioatdma_chan *ioat_chan,
 			   dma_addr_t *phys_complete);
-void ioat_kobject_add(struct ioatdma_device *ioat_dma, struct kobj_type *type);
-void ioat_kobject_del(struct ioatdma_device *ioat_dma);
-int ioat_dma_setup_interrupts(struct ioatdma_device *ioat_dma);
-void ioat_stop(struct ioatdma_chan *ioat_chan);
-int ioat_dma_probe(struct ioatdma_device *ioat_dma, int dca);
-int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca);
-struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);
 int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs);
-int ioat_enumerate_channels(struct ioatdma_device *ioat_dma);
-struct dma_async_tx_descriptor *
-ioat_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
-			   dma_addr_t dma_src, size_t len, unsigned long flags);
 void ioat_issue_pending(struct dma_chan *chan);
-int ioat_alloc_chan_resources(struct dma_chan *c);
-void ioat_free_chan_resources(struct dma_chan *c);
-void __ioat_restart_chan(struct ioatdma_chan *ioat_chan);
 bool reshape_ring(struct ioatdma_chan *ioat, int order);
 void __ioat_issue_pending(struct ioatdma_chan *ioat_chan);
 void ioat_timer_event(unsigned long data);
 int ioat_quiesce(struct ioatdma_chan *ioat_chan, unsigned long tmo);
 int ioat_reset_sync(struct ioatdma_chan *ioat_chan, unsigned long tmo);
+void __ioat_restart_chan(struct ioatdma_chan *ioat_chan);
 
-extern const struct sysfs_ops ioat_sysfs_ops;
-extern struct ioat_sysfs_entry ioat_version_attr;
-extern struct ioat_sysfs_entry ioat_cap_attr;
-extern int ioat_pending_level;
-extern int ioat_ring_alloc_order;
-extern struct kobj_type ioat_ktype;
-extern struct kmem_cache *ioat_cache;
-extern int ioat_ring_max_alloc_order;
-extern struct kmem_cache *ioat_sed_cache;
-
+/* IOAT Init functions */
+bool is_bwd_ioat(struct pci_dev *pdev);
+void ioat_kobject_add(struct ioatdma_device *ioat_dma, struct kobj_type *type);
+void ioat_kobject_del(struct ioatdma_device *ioat_dma);
+int ioat_dma_setup_interrupts(struct ioatdma_device *ioat_dma);
+void ioat_stop(struct ioatdma_chan *ioat_chan);
+struct dca_provider *ioat3_dca_init(struct pci_dev *pdev, void __iomem *iobase);
 #endif /* IOATDMA_H */
diff --git a/drivers/dma/ioat/dma_v3.c b/drivers/dma/ioat/dma_v3.c
index f6a194a3a463..d0ae8f7c97a6 100644
--- a/drivers/dma/ioat/dma_v3.c
+++ b/drivers/dma/ioat/dma_v3.c
@@ -62,107 +62,8 @@
 #include "hw.h"
 #include "dma.h"
 
-/* ioat hardware assumes at least two sources for raid operations */
-#define src_cnt_to_sw(x) ((x) + 2)
-#define src_cnt_to_hw(x) ((x) - 2)
-#define ndest_to_sw(x) ((x) + 1)
-#define ndest_to_hw(x) ((x) - 1)
-#define src16_cnt_to_sw(x) ((x) + 9)
-#define src16_cnt_to_hw(x) ((x) - 9)
-
-/* provide a lookup table for setting the source address in the base or
- * extended descriptor of an xor or pq descriptor
- */
-static const u8 xor_idx_to_desc = 0xe0;
-static const u8 xor_idx_to_field[] = { 1, 4, 5, 6, 7, 0, 1, 2 };
-static const u8 pq_idx_to_desc = 0xf8;
-static const u8 pq16_idx_to_desc[] = { 0, 0, 1, 1, 1, 1, 1, 1, 1,
-				       2, 2, 2, 2, 2, 2, 2 };
-static const u8 pq_idx_to_field[] = { 1, 4, 5, 0, 1, 2, 4, 5 };
-static const u8 pq16_idx_to_field[] = { 1, 4, 1, 2, 3, 4, 5, 6, 7,
-					0, 1, 2, 3, 4, 5, 6 };
-
 static void ioat3_eh(struct ioatdma_chan *ioat_chan);
 
-static void xor_set_src(struct ioat_raw_descriptor *descs[2],
-			dma_addr_t addr, u32 offset, int idx)
-{
-	struct ioat_raw_descriptor *raw = descs[xor_idx_to_desc >> idx & 1];
-
-	raw->field[xor_idx_to_field[idx]] = addr + offset;
-}
-
-static dma_addr_t pq_get_src(struct ioat_raw_descriptor *descs[2], int idx)
-{
-	struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
-
-	return raw->field[pq_idx_to_field[idx]];
-}
-
-static dma_addr_t pq16_get_src(struct ioat_raw_descriptor *desc[3], int idx)
-{
-	struct ioat_raw_descriptor *raw = desc[pq16_idx_to_desc[idx]];
-
-	return raw->field[pq16_idx_to_field[idx]];
-}
-
-static void pq_set_src(struct ioat_raw_descriptor *descs[2],
-		       dma_addr_t addr, u32 offset, u8 coef, int idx)
-{
-	struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *) descs[0];
-	struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
-
-	raw->field[pq_idx_to_field[idx]] = addr + offset;
-	pq->coef[idx] = coef;
-}
-
-static void pq16_set_src(struct ioat_raw_descriptor *desc[3],
-			dma_addr_t addr, u32 offset, u8 coef, unsigned idx)
-{
-	struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *)desc[0];
-	struct ioat_pq16a_descriptor *pq16 =
-		(struct ioat_pq16a_descriptor *)desc[1];
-	struct ioat_raw_descriptor *raw = desc[pq16_idx_to_desc[idx]];
-
-	raw->field[pq16_idx_to_field[idx]] = addr + offset;
-
-	if (idx < 8)
-		pq->coef[idx] = coef;
-	else
-		pq16->coef[idx - 8] = coef;
-}
-
-static struct ioat_sed_ent *
-ioat3_alloc_sed(struct ioatdma_device *ioat_dma, unsigned int hw_pool)
-{
-	struct ioat_sed_ent *sed;
-	gfp_t flags = __GFP_ZERO | GFP_ATOMIC;
-
-	sed = kmem_cache_alloc(ioat_sed_cache, flags);
-	if (!sed)
-		return NULL;
-
-	sed->hw_pool = hw_pool;
-	sed->hw = dma_pool_alloc(ioat_dma->sed_hw_pool[hw_pool],
-				 flags, &sed->dma);
-	if (!sed->hw) {
-		kmem_cache_free(ioat_sed_cache, sed);
-		return NULL;
-	}
-
-	return sed;
-}
-
-static void
-ioat3_free_sed(struct ioatdma_device *ioat_dma, struct ioat_sed_ent *sed)
-{
-	if (!sed)
-		return;
-
-	dma_pool_free(ioat_dma->sed_hw_pool[sed->hw_pool], sed->hw, sed->dma);
-	kmem_cache_free(ioat_sed_cache, sed);
-}
-
 static bool desc_has_ext(struct ioat_ring_ent *desc)
 {
 	struct ioat_dma_descriptor *hw = desc->hw;
@@ -184,6 +85,16 @@ static bool desc_has_ext(struct ioat_ring_ent *desc)
 	return false;
 }
 
+static void
+ioat3_free_sed(struct ioatdma_device *ioat_dma, struct ioat_sed_ent *sed)
+{
+	if (!sed)
+		return;
+
+	dma_pool_free(ioat_dma->sed_hw_pool[sed->hw_pool], sed->hw, sed->dma);
+	kmem_cache_free(ioat_sed_cache, sed);
+}
+
 static u64 ioat3_get_current_completion(struct ioatdma_chan *ioat_chan)
 {
 	u64 phys_complete;
@@ -530,556 +441,6 @@ ioat_tx_status(struct dma_chan *c, dma_cookie_t cookie,
 	return dma_cookie_status(c, cookie, txstate);
 }
 
-static struct dma_async_tx_descriptor *
-__ioat_prep_xor_lock(struct dma_chan *c, enum sum_check_flags *result,
-		      dma_addr_t dest, dma_addr_t *src, unsigned int src_cnt,
-		      size_t len, unsigned long flags)
-{
-	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
-	struct ioat_ring_ent *compl_desc;
-	struct ioat_ring_ent *desc;
-	struct ioat_ring_ent *ext;
-	size_t total_len = len;
-	struct ioat_xor_descriptor *xor;
-	struct ioat_xor_ext_descriptor *xor_ex = NULL;
-	struct ioat_dma_descriptor *hw;
-	int num_descs, with_ext, idx, i;
-	u32 offset = 0;
-	u8 op = result ? IOAT_OP_XOR_VAL : IOAT_OP_XOR;
-
-	BUG_ON(src_cnt < 2);
-
-	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
-	/* we need 2x the number of descriptors to cover greater than 5
-	 * sources
-	 */
-	if (src_cnt > 5) {
-		with_ext = 1;
-		num_descs *= 2;
-	} else
-		with_ext = 0;
-
-	/* completion writes from the raid engine may pass completion
-	 * writes from the legacy engine, so we need one extra null
-	 * (legacy) descriptor to ensure all completion writes arrive in
-	 * order.
-	 */
-	if (likely(num_descs) &&
-	    ioat_check_space_lock(ioat_chan, num_descs+1) == 0)
-		idx = ioat_chan->head;
-	else
-		return NULL;
-	i = 0;
-	do {
-		struct ioat_raw_descriptor *descs[2];
-		size_t xfer_size = min_t(size_t,
-					 len, 1 << ioat_chan->xfercap_log);
-		int s;
-
-		desc = ioat_get_ring_ent(ioat_chan, idx + i);
-		xor = desc->xor;
-
-		/* save a branch by unconditionally retrieving the
-		 * extended descriptor xor_set_src() knows to not write
-		 * to it in the single descriptor case
-		 */
-		ext = ioat_get_ring_ent(ioat_chan, idx + i + 1);
-		xor_ex = ext->xor_ex;
-
-		descs[0] = (struct ioat_raw_descriptor *) xor;
-		descs[1] = (struct ioat_raw_descriptor *) xor_ex;
-		for (s = 0; s < src_cnt; s++)
-			xor_set_src(descs, src[s], offset, s);
-		xor->size = xfer_size;
-		xor->dst_addr = dest + offset;
-		xor->ctl = 0;
-		xor->ctl_f.op = op;
-		xor->ctl_f.src_cnt = src_cnt_to_hw(src_cnt);
-
-		len -= xfer_size;
-		offset += xfer_size;
-		dump_desc_dbg(ioat_chan, desc);
-	} while ((i += 1 + with_ext) < num_descs);
-
-	/* last xor descriptor carries the unmap parameters and fence bit */
-	desc->txd.flags = flags;
-	desc->len = total_len;
-	if (result)
-		desc->result = result;
-	xor->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
-
-	/* completion descriptor carries interrupt bit */
-	compl_desc = ioat_get_ring_ent(ioat_chan, idx + i);
-	compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
-	hw = compl_desc->hw;
-	hw->ctl = 0;
-	hw->ctl_f.null = 1;
-	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
-	hw->ctl_f.compl_write = 1;
-	hw->size = NULL_DESC_BUFFER_SIZE;
-	dump_desc_dbg(ioat_chan, compl_desc);
-
-	/* we leave the channel locked to ensure in order submission */
-	return &compl_desc->txd;
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
-	       unsigned int src_cnt, size_t len, unsigned long flags)
-{
-	return __ioat_prep_xor_lock(chan, NULL, dest, src, src_cnt, len, flags);
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_xor_val(struct dma_chan *chan, dma_addr_t *src,
-		    unsigned int src_cnt, size_t len,
-		    enum sum_check_flags *result, unsigned long flags)
-{
-	/* the cleanup routine only sets bits on validate failure, it
-	 * does not clear bits on validate success... so clear it here
-	 */
-	*result = 0;
-
-	return __ioat_prep_xor_lock(chan, result, src[0], &src[1],
-				     src_cnt - 1, len, flags);
-}
-
-static void
-dump_pq_desc_dbg(struct ioatdma_chan *ioat_chan, struct ioat_ring_ent *desc,
-		 struct ioat_ring_ent *ext)
-{
-	struct device *dev = to_dev(ioat_chan);
-	struct ioat_pq_descriptor *pq = desc->pq;
-	struct ioat_pq_ext_descriptor *pq_ex = ext ? ext->pq_ex : NULL;
-	struct ioat_raw_descriptor *descs[] = { (void *) pq, (void *) pq_ex };
-	int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
-	int i;
-
-	dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
-		" sz: %#10.8x ctl: %#x (op: %#x int: %d compl: %d pq: '%s%s'"
-		" src_cnt: %d)\n",
-		desc_id(desc), (unsigned long long) desc->txd.phys,
-		(unsigned long long) (pq_ex ? pq_ex->next : pq->next),
-		desc->txd.flags, pq->size, pq->ctl, pq->ctl_f.op, pq->ctl_f.int_en,
-		pq->ctl_f.compl_write,
-		pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
-		pq->ctl_f.src_cnt);
-	for (i = 0; i < src_cnt; i++)
-		dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
-			(unsigned long long) pq_get_src(descs, i), pq->coef[i]);
-	dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
-	dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
-	dev_dbg(dev, "\tNEXT: %#llx\n", pq->next);
-}
-
-static void dump_pq16_desc_dbg(struct ioatdma_chan *ioat_chan,
-			       struct ioat_ring_ent *desc)
-{
-	struct device *dev = to_dev(ioat_chan);
-	struct ioat_pq_descriptor *pq = desc->pq;
-	struct ioat_raw_descriptor *descs[] = { (void *)pq,
-						(void *)pq,
-						(void *)pq };
-	int src_cnt = src16_cnt_to_sw(pq->ctl_f.src_cnt);
-	int i;
-
-	if (desc->sed) {
-		descs[1] = (void *)desc->sed->hw;
-		descs[2] = (void *)desc->sed->hw + 64;
-	}
-
-	dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
-		" sz: %#x ctl: %#x (op: %#x int: %d compl: %d pq: '%s%s'"
-		" src_cnt: %d)\n",
-		desc_id(desc), (unsigned long long) desc->txd.phys,
-		(unsigned long long) pq->next,
-		desc->txd.flags, pq->size, pq->ctl,
-		pq->ctl_f.op, pq->ctl_f.int_en,
-		pq->ctl_f.compl_write,
-		pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
-		pq->ctl_f.src_cnt);
-	for (i = 0; i < src_cnt; i++) {
-		dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
-			(unsigned long long) pq16_get_src(descs, i),
-			pq->coef[i]);
-	}
-	dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
-	dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
-}
-
-static struct dma_async_tx_descriptor *
-__ioat_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
-		     const dma_addr_t *dst, const dma_addr_t *src,
-		     unsigned int src_cnt, const unsigned char *scf,
-		     size_t len, unsigned long flags)
-{
-	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
-	struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
-	struct ioat_ring_ent *compl_desc;
-	struct ioat_ring_ent *desc;
-	struct ioat_ring_ent *ext;
-	size_t total_len = len;
-	struct ioat_pq_descriptor *pq;
-	struct ioat_pq_ext_descriptor *pq_ex = NULL;
-	struct ioat_dma_descriptor *hw;
-	u32 offset = 0;
-	u8 op = result ? IOAT_OP_PQ_VAL : IOAT_OP_PQ;
-	int i, s, idx, with_ext, num_descs;
-	int cb32 = (ioat_dma->version < IOAT_VER_3_3) ? 1 : 0;
-
-	dev_dbg(to_dev(ioat_chan), "%s\n", __func__);
-	/* the engine requires at least two sources (we provide
-	 * at least 1 implied source in the DMA_PREP_CONTINUE case)
-	 */
-	BUG_ON(src_cnt + dmaf_continue(flags) < 2);
-
-	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
-	/* we need 2x the number of descriptors to cover greater than 3
-	 * sources (we need 1 extra source in the q-only continuation
-	 * case and 3 extra sources in the p+q continuation case.
-	 */
-	if (src_cnt + dmaf_p_disabled_continue(flags) > 3 ||
-	    (dmaf_continue(flags) && !dmaf_p_disabled_continue(flags))) {
-		with_ext = 1;
-		num_descs *= 2;
-	} else
-		with_ext = 0;
-
-	/* completion writes from the raid engine may pass completion
-	 * writes from the legacy engine, so we need one extra null
-	 * (legacy) descriptor to ensure all completion writes arrive in
-	 * order.
-	 */
-	if (likely(num_descs) &&
-	    ioat_check_space_lock(ioat_chan, num_descs + cb32) == 0)
-		idx = ioat_chan->head;
-	else
-		return NULL;
-	i = 0;
-	do {
-		struct ioat_raw_descriptor *descs[2];
-		size_t xfer_size = min_t(size_t, len,
-					 1 << ioat_chan->xfercap_log);
-
-		desc = ioat_get_ring_ent(ioat_chan, idx + i);
-		pq = desc->pq;
-
-		/* save a branch by unconditionally retrieving the
-		 * extended descriptor pq_set_src() knows to not write
-		 * to it in the single descriptor case
-		 */
-		ext = ioat_get_ring_ent(ioat_chan, idx + i + with_ext);
-		pq_ex = ext->pq_ex;
-
-		descs[0] = (struct ioat_raw_descriptor *) pq;
-		descs[1] = (struct ioat_raw_descriptor *) pq_ex;
-
-		for (s = 0; s < src_cnt; s++)
-			pq_set_src(descs, src[s], offset, scf[s], s);
-
-		/* see the comment for dma_maxpq in include/linux/dmaengine.h */
-		if (dmaf_p_disabled_continue(flags))
-			pq_set_src(descs, dst[1], offset, 1, s++);
-		else if (dmaf_continue(flags)) {
-			pq_set_src(descs, dst[0], offset, 0, s++);
-			pq_set_src(descs, dst[1], offset, 1, s++);
-			pq_set_src(descs, dst[1], offset, 0, s++);
-		}
-		pq->size = xfer_size;
-		pq->p_addr = dst[0] + offset;
-		pq->q_addr = dst[1] + offset;
-		pq->ctl = 0;
-		pq->ctl_f.op = op;
-		/* we turn on descriptor write back error status */
-		if (ioat_dma->cap & IOAT_CAP_DWBES)
-			pq->ctl_f.wb_en = result ? 1 : 0;
-		pq->ctl_f.src_cnt = src_cnt_to_hw(s);
-		pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
-		pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);
-
-		len -= xfer_size;
-		offset += xfer_size;
-	} while ((i += 1 + with_ext) < num_descs);
-
-	/* last pq descriptor carries the unmap parameters and fence bit */
-	desc->txd.flags = flags;
-	desc->len = total_len;
-	if (result)
-		desc->result = result;
-	pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
-	dump_pq_desc_dbg(ioat_chan, desc, ext);
-
-	if (!cb32) {
-		pq->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
-		pq->ctl_f.compl_write = 1;
-		compl_desc = desc;
-	} else {
-		/* completion descriptor carries interrupt bit */
-		compl_desc = ioat_get_ring_ent(ioat_chan, idx + i);
-		compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
-		hw = compl_desc->hw;
-		hw->ctl = 0;
-		hw->ctl_f.null = 1;
-		hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
-		hw->ctl_f.compl_write = 1;
-		hw->size = NULL_DESC_BUFFER_SIZE;
-		dump_desc_dbg(ioat_chan, compl_desc);
-	}
-
-
-	/* we leave the channel locked to ensure in order submission */
-	return &compl_desc->txd;
-}
-
-static struct dma_async_tx_descriptor *
-__ioat_prep_pq16_lock(struct dma_chan *c, enum sum_check_flags *result,
-		       const dma_addr_t *dst, const dma_addr_t *src,
-		       unsigned int src_cnt, const unsigned char *scf,
-		       size_t len, unsigned long flags)
-{
-	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
-	struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
-	struct ioat_ring_ent *desc;
-	size_t total_len = len;
-	struct ioat_pq_descriptor *pq;
-	u32 offset = 0;
-	u8 op;
-	int i, s, idx, num_descs;
-
-	/* this function is only called with 9-16 sources */
-	op = result ? IOAT_OP_PQ_VAL_16S : IOAT_OP_PQ_16S;
-
-	dev_dbg(to_dev(ioat_chan), "%s\n", __func__);
-
-	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
-
-	/*
-	 * 16 source pq is only available on cb3.3 and has no completion
-	 * write hw bug.
-	 */
-	if (num_descs && ioat_check_space_lock(ioat_chan, num_descs) == 0)
-		idx = ioat_chan->head;
-	else
-		return NULL;
-
-	i = 0;
-
-	do {
-		struct ioat_raw_descriptor *descs[4];
-		size_t xfer_size = min_t(size_t, len,
-					 1 << ioat_chan->xfercap_log);
-
-		desc = ioat_get_ring_ent(ioat_chan, idx + i);
-		pq = desc->pq;
-
-		descs[0] = (struct ioat_raw_descriptor *) pq;
-
-		desc->sed = ioat3_alloc_sed(ioat_dma, (src_cnt-2) >> 3);
-		if (!desc->sed) {
-			dev_err(to_dev(ioat_chan),
-				"%s: no free sed entries\n", __func__);
-			return NULL;
-		}
-
-		pq->sed_addr = desc->sed->dma;
-		desc->sed->parent = desc;
-
-		descs[1] = (struct ioat_raw_descriptor *)desc->sed->hw;
-		descs[2] = (void *)descs[1] + 64;
-
-		for (s = 0; s < src_cnt; s++)
-			pq16_set_src(descs, src[s], offset, scf[s], s);
-
-		/* see the comment for dma_maxpq in include/linux/dmaengine.h */
-		if (dmaf_p_disabled_continue(flags))
-			pq16_set_src(descs, dst[1], offset, 1, s++);
-		else if (dmaf_continue(flags)) {
-			pq16_set_src(descs, dst[0], offset, 0, s++);
-			pq16_set_src(descs, dst[1], offset, 1, s++);
-			pq16_set_src(descs, dst[1], offset, 0, s++);
-		}
-
-		pq->size = xfer_size;
-		pq->p_addr = dst[0] + offset;
-		pq->q_addr = dst[1] + offset;
-		pq->ctl = 0;
-		pq->ctl_f.op = op;
-		pq->ctl_f.src_cnt = src16_cnt_to_hw(s);
-		/* we turn on descriptor write back error status */
-		if (ioat_dma->cap & IOAT_CAP_DWBES)
-			pq->ctl_f.wb_en = result ? 1 : 0;
-		pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
-		pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);
-
-		len -= xfer_size;
-		offset += xfer_size;
-	} while (++i < num_descs);
-
-	/* last pq descriptor carries the unmap parameters and fence bit */
-	desc->txd.flags = flags;
-	desc->len = total_len;
-	if (result)
-		desc->result = result;
-	pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
-
-	/* with cb3.3 we should be able to do completion w/o a null desc */
-	pq->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
-	pq->ctl_f.compl_write = 1;
-
-	dump_pq16_desc_dbg(ioat_chan, desc);
-
-	/* we leave the channel locked to ensure in order submission */
-	return &desc->txd;
-}
-
-static int src_cnt_flags(unsigned int src_cnt, unsigned long flags)
-{
-	if (dmaf_p_disabled_continue(flags))
-		return src_cnt + 1;
-	else if (dmaf_continue(flags))
-		return src_cnt + 3;
-	else
-		return src_cnt;
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
-	      unsigned int src_cnt, const unsigned char *scf, size_t len,
-	      unsigned long flags)
-{
-	/* specify valid address for disabled result */
-	if (flags & DMA_PREP_PQ_DISABLE_P)
-		dst[0] = dst[1];
-	if (flags & DMA_PREP_PQ_DISABLE_Q)
-		dst[1] = dst[0];
-
-	/* handle the single source multiply case from the raid6
-	 * recovery path
-	 */
-	if ((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1) {
-		dma_addr_t single_source[2];
-		unsigned char single_source_coef[2];
-
-		BUG_ON(flags & DMA_PREP_PQ_DISABLE_Q);
-		single_source[0] = src[0];
-		single_source[1] = src[0];
-		single_source_coef[0] = scf[0];
-		single_source_coef[1] = 0;
-
-		return src_cnt_flags(src_cnt, flags) > 8 ?
-			__ioat_prep_pq16_lock(chan, NULL, dst, single_source,
-					       2, single_source_coef, len,
-					       flags) :
-			__ioat_prep_pq_lock(chan, NULL, dst, single_source, 2,
-					     single_source_coef, len, flags);
-
-	} else {
-		return src_cnt_flags(src_cnt, flags) > 8 ?
-			__ioat_prep_pq16_lock(chan, NULL, dst, src, src_cnt,
-					       scf, len, flags) :
-			__ioat_prep_pq_lock(chan, NULL, dst, src, src_cnt,
-					     scf, len, flags);
-	}
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
-		  unsigned int src_cnt, const unsigned char *scf, size_t len,
-		  enum sum_check_flags *pqres, unsigned long flags)
-{
-	/* specify valid address for disabled result */
-	if (flags & DMA_PREP_PQ_DISABLE_P)
-		pq[0] = pq[1];
-	if (flags & DMA_PREP_PQ_DISABLE_Q)
-		pq[1] = pq[0];
-
-	/* the cleanup routine only sets bits on validate failure, it
-	 * does not clear bits on validate success... so clear it here
-	 */
-	*pqres = 0;
-
-	return src_cnt_flags(src_cnt, flags) > 8 ?
-		__ioat_prep_pq16_lock(chan, pqres, pq, src, src_cnt, scf, len,
-				       flags) :
-		__ioat_prep_pq_lock(chan, pqres, pq, src, src_cnt, scf, len,
-				     flags);
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_pqxor(struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
-		 unsigned int src_cnt, size_t len, unsigned long flags)
-{
-	unsigned char scf[src_cnt];
-	dma_addr_t pq[2];
-
-	memset(scf, 0, src_cnt);
-	pq[0] = dst;
-	flags |= DMA_PREP_PQ_DISABLE_Q;
-	pq[1] = dst; /* specify valid address for disabled result */
-
-	return src_cnt_flags(src_cnt, flags) > 8 ?
-		__ioat_prep_pq16_lock(chan, NULL, pq, src, src_cnt, scf, len,
-				       flags) :
-		__ioat_prep_pq_lock(chan, NULL, pq, src, src_cnt, scf, len,
-				     flags);
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
-		     unsigned int src_cnt, size_t len,
-		     enum sum_check_flags *result, unsigned long flags)
-{
-	unsigned char scf[src_cnt];
-	dma_addr_t pq[2];
-
-	/* the cleanup routine only sets bits on validate failure, it
-	 * does not clear bits on validate success... so clear it here
-	 */
-	*result = 0;
-
-	memset(scf, 0, src_cnt);
-	pq[0] = src[0];
-	flags |= DMA_PREP_PQ_DISABLE_Q;
-	pq[1] = pq[0]; /* specify valid address for disabled result */
-
-	return src_cnt_flags(src_cnt, flags) > 8 ?
-		__ioat_prep_pq16_lock(chan, result, pq, &src[1], src_cnt - 1,
-				       scf, len, flags) :
-		__ioat_prep_pq_lock(chan, result, pq, &src[1], src_cnt - 1,
-				     scf, len, flags);
-}
-
-struct dma_async_tx_descriptor *
-ioat_prep_interrupt_lock(struct dma_chan *c, unsigned long flags)
-{
-	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
-	struct ioat_ring_ent *desc;
-	struct ioat_dma_descriptor *hw;
-
-	if (ioat_check_space_lock(ioat_chan, 1) == 0)
-		desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head);
-	else
-		return NULL;
-
-	hw = desc->hw;
-	hw->ctl = 0;
-	hw->ctl_f.null = 1;
-	hw->ctl_f.int_en = 1;
-	hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
-	hw->ctl_f.compl_write = 1;
-	hw->size = NULL_DESC_BUFFER_SIZE;
-	hw->src_addr = 0;
-	hw->dst_addr = 0;
-
-	desc->txd.flags = flags;
-	desc->len = 1;
-
-	dump_desc_dbg(ioat_chan, desc);
-
-	/* we leave the channel locked to ensure in order submission */
-	return &desc->txd;
-}
-
 static int ioat3_irq_reinit(struct ioatdma_device *ioat_dma)
 {
 	struct pci_dev *pdev = ioat_dma->pdev;
diff --git a/drivers/dma/ioat/init.c b/drivers/dma/ioat/init.c
index de8141c7cd01..6b8fd49cf718 100644
--- a/drivers/dma/ioat/init.c
+++ b/drivers/dma/ioat/init.c
@@ -110,6 +110,9 @@ MODULE_DEVICE_TABLE(pci, ioat_pci_tbl);
 
 static int ioat_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id);
 static void ioat_remove(struct pci_dev *pdev);
+static void
+ioat_init_channel(struct ioatdma_device *ioat_dma,
+		  struct ioatdma_chan *ioat_chan, int idx);
 
 static int ioat_dca_enabled = 1;
 module_param(ioat_dca_enabled, int, 0644);
@@ -269,7 +272,7 @@ static void ioat_dma_test_callback(void *dma_async_param)
  * ioat_dma_self_test - Perform a IOAT transaction to verify the HW works.
  * @ioat_dma: dma device to be tested
  */
-int ioat_dma_self_test(struct ioatdma_device *ioat_dma)
+static int ioat_dma_self_test(struct ioatdma_device *ioat_dma)
 {
 	int i;
 	u8 *src;
@@ -453,7 +456,6 @@ err_no_irq:
 	dev_err(dev, "no usable interrupts\n");
 	return err;
 }
-EXPORT_SYMBOL(ioat_dma_setup_interrupts);
 
 static void ioat_disable_interrupts(struct ioatdma_device *ioat_dma)
 {
@@ -461,7 +463,7 @@ static void ioat_disable_interrupts(struct ioatdma_device *ioat_dma)
 	writeb(0, ioat_dma->reg_base + IOAT_INTRCTRL_OFFSET);
 }
 
-int ioat_probe(struct ioatdma_device *ioat_dma)
+static int ioat_probe(struct ioatdma_device *ioat_dma)
 {
 	int err = -ENODEV;
 	struct dma_device *dma = &ioat_dma->dma_dev;
@@ -517,7 +519,7 @@ err_dma_pool:
 	return err;
 }
 
-int ioat_register(struct ioatdma_device *ioat_dma)
+static int ioat_register(struct ioatdma_device *ioat_dma)
 {
 	int err = dma_async_device_register(&ioat_dma->dma_dev);
 
@@ -530,7 +532,7 @@ int ioat_register(struct ioatdma_device *ioat_dma)
 	return err;
 }
 
-void ioat_dma_remove(struct ioatdma_device *ioat_dma)
+static void ioat_dma_remove(struct ioatdma_device *ioat_dma)
 {
 	struct dma_device *dma = &ioat_dma->dma_dev;
 
@@ -550,7 +552,7 @@ void ioat_dma_remove(struct ioatdma_device *ioat_dma)
  * ioat_enumerate_channels - find and initialize the device's channels
  * @ioat_dma: the ioat dma device to be enumerated
  */
-int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
+static int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
 {
 	struct ioatdma_chan *ioat_chan;
 	struct device *dev = &ioat_dma->pdev->dev;
@@ -593,7 +595,7 @@ int ioat_enumerate_channels(struct ioatdma_device *ioat_dma)
  * ioat_free_chan_resources - release all the descriptors
  * @chan: the channel to be cleaned
  */
-void ioat_free_chan_resources(struct dma_chan *c)
+static void ioat_free_chan_resources(struct dma_chan *c)
 {
 	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
 	struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
@@ -646,7 +648,7 @@ void ioat_free_chan_resources(struct dma_chan *c)
 /* ioat_alloc_chan_resources - allocate/initialize ioat descriptor ring
  * @chan: channel to be initialized
  */
-int ioat_alloc_chan_resources(struct dma_chan *c)
+static int ioat_alloc_chan_resources(struct dma_chan *c)
 {
 	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
 	struct ioat_ring_ent **ring;
@@ -712,7 +714,7 @@ int ioat_alloc_chan_resources(struct dma_chan *c)
 }
 
 /* common channel initialization */
-void
+static void
 ioat_init_channel(struct ioatdma_device *ioat_dma,
 		  struct ioatdma_chan *ioat_chan, int idx)
 {
@@ -1048,7 +1050,7 @@ static void ioat3_intr_quirk(struct ioatdma_device *ioat_dma)
 	}
 }
 
-int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
+static int ioat3_dma_probe(struct ioatdma_device *ioat_dma, int dca)
 {
 	struct pci_dev *pdev = ioat_dma->pdev;
 	int dca_en = system_has_dca_enabled(pdev);
diff --git a/drivers/dma/ioat/prep.c b/drivers/dma/ioat/prep.c
new file mode 100644
index 000000000000..e323a4036908
--- /dev/null
+++ b/drivers/dma/ioat/prep.c
@@ -0,0 +1,707 @@
+/*
+ * Intel I/OAT DMA Linux driver
+ * Copyright(c) 2004 - 2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * The full GNU General Public License is included in this distribution in
+ * the file called "COPYING".
+ *
+ */
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/gfp.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/prefetch.h>
+#include "../dmaengine.h"
+#include "registers.h"
+#include "hw.h"
+#include "dma.h"
+
+/* provide a lookup table for setting the source address in the base or
+ * extended descriptor of an xor or pq descriptor
+ */
+static const u8 xor_idx_to_desc = 0xe0;
+static const u8 xor_idx_to_field[] = { 1, 4, 5, 6, 7, 0, 1, 2 };
+static const u8 pq_idx_to_desc = 0xf8;
+static const u8 pq16_idx_to_desc[] = { 0, 0, 1, 1, 1, 1, 1, 1, 1,
+				       2, 2, 2, 2, 2, 2, 2 };
+static const u8 pq_idx_to_field[] = { 1, 4, 5, 0, 1, 2, 4, 5 };
+static const u8 pq16_idx_to_field[] = { 1, 4, 1, 2, 3, 4, 5, 6, 7,
+					0, 1, 2, 3, 4, 5, 6 };
+
+static void xor_set_src(struct ioat_raw_descriptor *descs[2],
+			dma_addr_t addr, u32 offset, int idx)
+{
+	struct ioat_raw_descriptor *raw = descs[xor_idx_to_desc >> idx & 1];
+
+	raw->field[xor_idx_to_field[idx]] = addr + offset;
+}
+
+static dma_addr_t pq_get_src(struct ioat_raw_descriptor *descs[2], int idx)
+{
+	struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
+
+	return raw->field[pq_idx_to_field[idx]];
+}
+
+static dma_addr_t pq16_get_src(struct ioat_raw_descriptor *desc[3], int idx)
+{
+	struct ioat_raw_descriptor *raw = desc[pq16_idx_to_desc[idx]];
+
+	return raw->field[pq16_idx_to_field[idx]];
+}
+
+static void pq_set_src(struct ioat_raw_descriptor *descs[2],
+		       dma_addr_t addr, u32 offset, u8 coef, int idx)
+{
+	struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *) descs[0];
+	struct ioat_raw_descriptor *raw = descs[pq_idx_to_desc >> idx & 1];
+
+	raw->field[pq_idx_to_field[idx]] = addr + offset;
+	pq->coef[idx] = coef;
+}
+
+static void pq16_set_src(struct ioat_raw_descriptor *desc[3],
+			dma_addr_t addr, u32 offset, u8 coef, unsigned idx)
+{
+	struct ioat_pq_descriptor *pq = (struct ioat_pq_descriptor *)desc[0];
+	struct ioat_pq16a_descriptor *pq16 =
+		(struct ioat_pq16a_descriptor *)desc[1];
+	struct ioat_raw_descriptor *raw = desc[pq16_idx_to_desc[idx]];
+
+	raw->field[pq16_idx_to_field[idx]] = addr + offset;
+
+	if (idx < 8)
+		pq->coef[idx] = coef;
+	else
+		pq16->coef[idx - 8] = coef;
+}
+
+static struct ioat_sed_ent *
+ioat3_alloc_sed(struct ioatdma_device *ioat_dma, unsigned int hw_pool)
+{
+	struct ioat_sed_ent *sed;
+	gfp_t flags = __GFP_ZERO | GFP_ATOMIC;
+
+	sed = kmem_cache_alloc(ioat_sed_cache, flags);
+	if (!sed)
+		return NULL;
+
+	sed->hw_pool = hw_pool;
+	sed->hw = dma_pool_alloc(ioat_dma->sed_hw_pool[hw_pool],
+				 flags, &sed->dma);
+	if (!sed->hw) {
+		kmem_cache_free(ioat_sed_cache, sed);
+		return NULL;
+	}
+
+	return sed;
+}
+
+struct dma_async_tx_descriptor *
+ioat_dma_prep_memcpy_lock(struct dma_chan *c, dma_addr_t dma_dest,
+			   dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioat_dma_descriptor *hw;
+	struct ioat_ring_ent *desc;
+	dma_addr_t dst = dma_dest;
+	dma_addr_t src = dma_src;
+	size_t total_len = len;
+	int num_descs, idx, i;
+
+	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
+	if (likely(num_descs) &&
+	    ioat_check_space_lock(ioat_chan, num_descs) == 0)
+		idx = ioat_chan->head;
+	else
+		return NULL;
+	i = 0;
+	do {
+		size_t copy = min_t(size_t, len, 1 << ioat_chan->xfercap_log);
+
+		desc = ioat_get_ring_ent(ioat_chan, idx + i);
+		hw = desc->hw;
+
+		hw->size = copy;
+		hw->ctl = 0;
+		hw->src_addr = src;
+		hw->dst_addr = dst;
+
+		len -= copy;
+		dst += copy;
+		src += copy;
+		dump_desc_dbg(ioat_chan, desc);
+	} while (++i < num_descs);
+
+	desc->txd.flags = flags;
+	desc->len = total_len;
+	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+	hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+	hw->ctl_f.compl_write = 1;
+	dump_desc_dbg(ioat_chan, desc);
+	/* we leave the channel locked to ensure in order submission */
+
+	return &desc->txd;
+}
+
+
+static struct dma_async_tx_descriptor *
+__ioat_prep_xor_lock(struct dma_chan *c, enum sum_check_flags *result,
+		      dma_addr_t dest, dma_addr_t *src, unsigned int src_cnt,
+		      size_t len, unsigned long flags)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioat_ring_ent *compl_desc;
+	struct ioat_ring_ent *desc;
+	struct ioat_ring_ent *ext;
+	size_t total_len = len;
+	struct ioat_xor_descriptor *xor;
+	struct ioat_xor_ext_descriptor *xor_ex = NULL;
+	struct ioat_dma_descriptor *hw;
+	int num_descs, with_ext, idx, i;
+	u32 offset = 0;
+	u8 op = result ? IOAT_OP_XOR_VAL : IOAT_OP_XOR;
+
+	BUG_ON(src_cnt < 2);
+
+	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
+	/* we need 2x the number of descriptors to cover greater than 5
+	 * sources
+	 */
+	if (src_cnt > 5) {
+		with_ext = 1;
+		num_descs *= 2;
+	} else
+		with_ext = 0;
+
+	/* completion writes from the raid engine may pass completion
+	 * writes from the legacy engine, so we need one extra null
+	 * (legacy) descriptor to ensure all completion writes arrive in
+	 * order.
+	 */
+	if (likely(num_descs) &&
+	    ioat_check_space_lock(ioat_chan, num_descs+1) == 0)
+		idx = ioat_chan->head;
+	else
+		return NULL;
+	i = 0;
+	do {
+		struct ioat_raw_descriptor *descs[2];
+		size_t xfer_size = min_t(size_t,
+					 len, 1 << ioat_chan->xfercap_log);
+		int s;
+
+		desc = ioat_get_ring_ent(ioat_chan, idx + i);
+		xor = desc->xor;
+
+		/* save a branch by unconditionally retrieving the
+		 * extended descriptor xor_set_src() knows to not write
+		 * to it in the single descriptor case
+		 */
+		ext = ioat_get_ring_ent(ioat_chan, idx + i + 1);
+		xor_ex = ext->xor_ex;
+
+		descs[0] = (struct ioat_raw_descriptor *) xor;
+		descs[1] = (struct ioat_raw_descriptor *) xor_ex;
+		for (s = 0; s < src_cnt; s++)
+			xor_set_src(descs, src[s], offset, s);
+		xor->size = xfer_size;
+		xor->dst_addr = dest + offset;
+		xor->ctl = 0;
+		xor->ctl_f.op = op;
+		xor->ctl_f.src_cnt = src_cnt_to_hw(src_cnt);
+
+		len -= xfer_size;
+		offset += xfer_size;
+		dump_desc_dbg(ioat_chan, desc);
+	} while ((i += 1 + with_ext) < num_descs);
+
+	/* last xor descriptor carries the unmap parameters and fence bit */
+	desc->txd.flags = flags;
+	desc->len = total_len;
+	if (result)
+		desc->result = result;
+	xor->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+
+	/* completion descriptor carries interrupt bit */
+	compl_desc = ioat_get_ring_ent(ioat_chan, idx + i);
+	compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
+	hw = compl_desc->hw;
+	hw->ctl = 0;
+	hw->ctl_f.null = 1;
+	hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+	hw->ctl_f.compl_write = 1;
+	hw->size = NULL_DESC_BUFFER_SIZE;
+	dump_desc_dbg(ioat_chan, compl_desc);
+
+	/* we leave the channel locked to ensure in order submission */
+	return &compl_desc->txd;
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_xor(struct dma_chan *chan, dma_addr_t dest, dma_addr_t *src,
+	       unsigned int src_cnt, size_t len, unsigned long flags)
+{
+	return __ioat_prep_xor_lock(chan, NULL, dest, src, src_cnt, len, flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_xor_val(struct dma_chan *chan, dma_addr_t *src,
+		    unsigned int src_cnt, size_t len,
+		    enum sum_check_flags *result, unsigned long flags)
+{
+	/* the cleanup routine only sets bits on validate failure, it
+	 * does not clear bits on validate success... so clear it here
+	 */
+	*result = 0;
+
+	return __ioat_prep_xor_lock(chan, result, src[0], &src[1],
+				     src_cnt - 1, len, flags);
+}
+
+static void
+dump_pq_desc_dbg(struct ioatdma_chan *ioat_chan, struct ioat_ring_ent *desc,
+		 struct ioat_ring_ent *ext)
+{
+	struct device *dev = to_dev(ioat_chan);
+	struct ioat_pq_descriptor *pq = desc->pq;
+	struct ioat_pq_ext_descriptor *pq_ex = ext ? ext->pq_ex : NULL;
+	struct ioat_raw_descriptor *descs[] = { (void *) pq, (void *) pq_ex };
+	int src_cnt = src_cnt_to_sw(pq->ctl_f.src_cnt);
+	int i;
+
+	dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
+		" sz: %#10.8x ctl: %#x (op: %#x int: %d compl: %d pq: '%s%s'"
+		" src_cnt: %d)\n",
+		desc_id(desc), (unsigned long long) desc->txd.phys,
+		(unsigned long long) (pq_ex ? pq_ex->next : pq->next),
+		desc->txd.flags, pq->size, pq->ctl, pq->ctl_f.op,
+		pq->ctl_f.int_en, pq->ctl_f.compl_write,
+		pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
+		pq->ctl_f.src_cnt);
+	for (i = 0; i < src_cnt; i++)
+		dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
+			(unsigned long long) pq_get_src(descs, i), pq->coef[i]);
+	dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
+	dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
+	dev_dbg(dev, "\tNEXT: %#llx\n", pq->next);
+}
+
+static void dump_pq16_desc_dbg(struct ioatdma_chan *ioat_chan,
+			       struct ioat_ring_ent *desc)
+{
+	struct device *dev = to_dev(ioat_chan);
+	struct ioat_pq_descriptor *pq = desc->pq;
+	struct ioat_raw_descriptor *descs[] = { (void *)pq,
+						(void *)pq,
+						(void *)pq };
+	int src_cnt = src16_cnt_to_sw(pq->ctl_f.src_cnt);
+	int i;
+
+	if (desc->sed) {
+		descs[1] = (void *)desc->sed->hw;
+		descs[2] = (void *)desc->sed->hw + 64;
+	}
+
+	dev_dbg(dev, "desc[%d]: (%#llx->%#llx) flags: %#x"
+		" sz: %#x ctl: %#x (op: %#x int: %d compl: %d pq: '%s%s'"
+		" src_cnt: %d)\n",
+		desc_id(desc), (unsigned long long) desc->txd.phys,
+		(unsigned long long) pq->next,
+		desc->txd.flags, pq->size, pq->ctl,
+		pq->ctl_f.op, pq->ctl_f.int_en,
+		pq->ctl_f.compl_write,
+		pq->ctl_f.p_disable ? "" : "p", pq->ctl_f.q_disable ? "" : "q",
+		pq->ctl_f.src_cnt);
+	for (i = 0; i < src_cnt; i++) {
+		dev_dbg(dev, "\tsrc[%d]: %#llx coef: %#x\n", i,
+			(unsigned long long) pq16_get_src(descs, i),
+			pq->coef[i]);
+	}
+	dev_dbg(dev, "\tP: %#llx\n", pq->p_addr);
+	dev_dbg(dev, "\tQ: %#llx\n", pq->q_addr);
+}
+
+static struct dma_async_tx_descriptor *
+__ioat_prep_pq_lock(struct dma_chan *c, enum sum_check_flags *result,
+		     const dma_addr_t *dst, const dma_addr_t *src,
+		     unsigned int src_cnt, const unsigned char *scf,
+		     size_t len, unsigned long flags)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
+	struct ioat_ring_ent *compl_desc;
+	struct ioat_ring_ent *desc;
+	struct ioat_ring_ent *ext;
+	size_t total_len = len;
+	struct ioat_pq_descriptor *pq;
+	struct ioat_pq_ext_descriptor *pq_ex = NULL;
+	struct ioat_dma_descriptor *hw;
+	u32 offset = 0;
+	u8 op = result ? IOAT_OP_PQ_VAL : IOAT_OP_PQ;
+	int i, s, idx, with_ext, num_descs;
+	int cb32 = (ioat_dma->version < IOAT_VER_3_3) ? 1 : 0;
+
+	dev_dbg(to_dev(ioat_chan), "%s\n", __func__);
+	/* the engine requires at least two sources (we provide
+	 * at least 1 implied source in the DMA_PREP_CONTINUE case)
+	 */
+	BUG_ON(src_cnt + dmaf_continue(flags) < 2);
+
+	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
+	/* we need 2x the number of descriptors to cover greater than 3
+	 * sources (we need 1 extra source in the q-only continuation
+	 * case and 3 extra sources in the p+q continuation case.
+	 */
+	if (src_cnt + dmaf_p_disabled_continue(flags) > 3 ||
+	    (dmaf_continue(flags) && !dmaf_p_disabled_continue(flags))) {
+		with_ext = 1;
+		num_descs *= 2;
+	} else
+		with_ext = 0;
+
+	/* completion writes from the raid engine may pass completion
+	 * writes from the legacy engine, so we need one extra null
+	 * (legacy) descriptor to ensure all completion writes arrive in
+	 * order.
+	 */
+	if (likely(num_descs) &&
+	    ioat_check_space_lock(ioat_chan, num_descs + cb32) == 0)
+		idx = ioat_chan->head;
+	else
+		return NULL;
+	i = 0;
+	do {
+		struct ioat_raw_descriptor *descs[2];
+		size_t xfer_size = min_t(size_t, len,
+					 1 << ioat_chan->xfercap_log);
+
+		desc = ioat_get_ring_ent(ioat_chan, idx + i);
+		pq = desc->pq;
+
+		/* save a branch by unconditionally retrieving the
+		 * extended descriptor pq_set_src() knows to not write
+		 * to it in the single descriptor case
+		 */
+		ext = ioat_get_ring_ent(ioat_chan, idx + i + with_ext);
+		pq_ex = ext->pq_ex;
+
+		descs[0] = (struct ioat_raw_descriptor *) pq;
+		descs[1] = (struct ioat_raw_descriptor *) pq_ex;
+
+		for (s = 0; s < src_cnt; s++)
+			pq_set_src(descs, src[s], offset, scf[s], s);
+
+		/* see the comment for dma_maxpq in include/linux/dmaengine.h */
+		if (dmaf_p_disabled_continue(flags))
+			pq_set_src(descs, dst[1], offset, 1, s++);
+		else if (dmaf_continue(flags)) {
+			pq_set_src(descs, dst[0], offset, 0, s++);
+			pq_set_src(descs, dst[1], offset, 1, s++);
+			pq_set_src(descs, dst[1], offset, 0, s++);
+		}
+		pq->size = xfer_size;
+		pq->p_addr = dst[0] + offset;
+		pq->q_addr = dst[1] + offset;
+		pq->ctl = 0;
+		pq->ctl_f.op = op;
+		/* we turn on descriptor write back error status */
+		if (ioat_dma->cap & IOAT_CAP_DWBES)
+			pq->ctl_f.wb_en = result ? 1 : 0;
+		pq->ctl_f.src_cnt = src_cnt_to_hw(s);
+		pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
+		pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);
+
+		len -= xfer_size;
+		offset += xfer_size;
+	} while ((i += 1 + with_ext) < num_descs);
+
+	/* last pq descriptor carries the unmap parameters and fence bit */
+	desc->txd.flags = flags;
+	desc->len = total_len;
+	if (result)
+		desc->result = result;
+	pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+	dump_pq_desc_dbg(ioat_chan, desc, ext);
+
+	if (!cb32) {
+		pq->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+		pq->ctl_f.compl_write = 1;
+		compl_desc = desc;
+	} else {
+		/* completion descriptor carries interrupt bit */
+		compl_desc = ioat_get_ring_ent(ioat_chan, idx + i);
+		compl_desc->txd.flags = flags & DMA_PREP_INTERRUPT;
+		hw = compl_desc->hw;
+		hw->ctl = 0;
+		hw->ctl_f.null = 1;
+		hw->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+		hw->ctl_f.compl_write = 1;
+		hw->size = NULL_DESC_BUFFER_SIZE;
+		dump_desc_dbg(ioat_chan, compl_desc);
+	}
+
+
+	/* we leave the channel locked to ensure in order submission */
+	return &compl_desc->txd;
+}
+
+static struct dma_async_tx_descriptor *
+__ioat_prep_pq16_lock(struct dma_chan *c, enum sum_check_flags *result,
+		       const dma_addr_t *dst, const dma_addr_t *src,
+		       unsigned int src_cnt, const unsigned char *scf,
+		       size_t len, unsigned long flags)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
+	struct ioat_ring_ent *desc;
+	size_t total_len = len;
+	struct ioat_pq_descriptor *pq;
+	u32 offset = 0;
+	u8 op;
+	int i, s, idx, num_descs;
+
+	/* this function is only called with 9-16 sources */
+	op = result ? IOAT_OP_PQ_VAL_16S : IOAT_OP_PQ_16S;
+
+	dev_dbg(to_dev(ioat_chan), "%s\n", __func__);
+
+	num_descs = ioat_xferlen_to_descs(ioat_chan, len);
+
+	/*
+	 * 16 source pq is only available on cb3.3 and has no completion
+	 * write hw bug.
+	 */
+	if (num_descs && ioat_check_space_lock(ioat_chan, num_descs) == 0)
+		idx = ioat_chan->head;
+	else
+		return NULL;
+
+	i = 0;
+
+	do {
+		struct ioat_raw_descriptor *descs[4];
+		size_t xfer_size = min_t(size_t, len,
+					 1 << ioat_chan->xfercap_log);
+
+		desc = ioat_get_ring_ent(ioat_chan, idx + i);
+		pq = desc->pq;
+
+		descs[0] = (struct ioat_raw_descriptor *) pq;
+
+		desc->sed = ioat3_alloc_sed(ioat_dma, (src_cnt-2) >> 3);
+		if (!desc->sed) {
+			dev_err(to_dev(ioat_chan),
+				"%s: no free sed entries\n", __func__);
+			return NULL;
+		}
+
+		pq->sed_addr = desc->sed->dma;
+		desc->sed->parent = desc;
+
+		descs[1] = (struct ioat_raw_descriptor *)desc->sed->hw;
+		descs[2] = (void *)descs[1] + 64;
+
+		for (s = 0; s < src_cnt; s++)
+			pq16_set_src(descs, src[s], offset, scf[s], s);
+
+		/* see the comment for dma_maxpq in include/linux/dmaengine.h */
+		if (dmaf_p_disabled_continue(flags))
+			pq16_set_src(descs, dst[1], offset, 1, s++);
+		else if (dmaf_continue(flags)) {
+			pq16_set_src(descs, dst[0], offset, 0, s++);
+			pq16_set_src(descs, dst[1], offset, 1, s++);
+			pq16_set_src(descs, dst[1], offset, 0, s++);
+		}
+
+		pq->size = xfer_size;
+		pq->p_addr = dst[0] + offset;
+		pq->q_addr = dst[1] + offset;
+		pq->ctl = 0;
+		pq->ctl_f.op = op;
+		pq->ctl_f.src_cnt = src16_cnt_to_hw(s);
+		/* we turn on descriptor write back error status */
+		if (ioat_dma->cap & IOAT_CAP_DWBES)
+			pq->ctl_f.wb_en = result ? 1 : 0;
+		pq->ctl_f.p_disable = !!(flags & DMA_PREP_PQ_DISABLE_P);
+		pq->ctl_f.q_disable = !!(flags & DMA_PREP_PQ_DISABLE_Q);
+
+		len -= xfer_size;
+		offset += xfer_size;
+	} while (++i < num_descs);
+
+	/* last pq descriptor carries the unmap parameters and fence bit */
+	desc->txd.flags = flags;
+	desc->len = total_len;
+	if (result)
+		desc->result = result;
+	pq->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+
+	/* with cb3.3 we should be able to do completion w/o a null desc */
+	pq->ctl_f.int_en = !!(flags & DMA_PREP_INTERRUPT);
+	pq->ctl_f.compl_write = 1;
+
+	dump_pq16_desc_dbg(ioat_chan, desc);
+
+	/* we leave the channel locked to ensure in order submission */
+	return &desc->txd;
+}
+
+static int src_cnt_flags(unsigned int src_cnt, unsigned long flags)
+{
+	if (dmaf_p_disabled_continue(flags))
+		return src_cnt + 1;
+	else if (dmaf_continue(flags))
+		return src_cnt + 3;
+	else
+		return src_cnt;
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_pq(struct dma_chan *chan, dma_addr_t *dst, dma_addr_t *src,
+	      unsigned int src_cnt, const unsigned char *scf, size_t len,
+	      unsigned long flags)
+{
+	/* specify valid address for disabled result */
+	if (flags & DMA_PREP_PQ_DISABLE_P)
+		dst[0] = dst[1];
+	if (flags & DMA_PREP_PQ_DISABLE_Q)
+		dst[1] = dst[0];
+
+	/* handle the single source multiply case from the raid6
+	 * recovery path
+	 */
+	if ((flags & DMA_PREP_PQ_DISABLE_P) && src_cnt == 1) {
+		dma_addr_t single_source[2];
+		unsigned char single_source_coef[2];
+
+		BUG_ON(flags & DMA_PREP_PQ_DISABLE_Q);
+		single_source[0] = src[0];
+		single_source[1] = src[0];
+		single_source_coef[0] = scf[0];
+		single_source_coef[1] = 0;
+
+		return src_cnt_flags(src_cnt, flags) > 8 ?
+			__ioat_prep_pq16_lock(chan, NULL, dst, single_source,
+					       2, single_source_coef, len,
+					       flags) :
+			__ioat_prep_pq_lock(chan, NULL, dst, single_source, 2,
+					     single_source_coef, len, flags);
+
+	} else {
+		return src_cnt_flags(src_cnt, flags) > 8 ?
+			__ioat_prep_pq16_lock(chan, NULL, dst, src, src_cnt,
+					       scf, len, flags) :
+			__ioat_prep_pq_lock(chan, NULL, dst, src, src_cnt,
+					     scf, len, flags);
+	}
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_pq_val(struct dma_chan *chan, dma_addr_t *pq, dma_addr_t *src,
+		  unsigned int src_cnt, const unsigned char *scf, size_t len,
+		  enum sum_check_flags *pqres, unsigned long flags)
+{
+	/* specify valid address for disabled result */
+	if (flags & DMA_PREP_PQ_DISABLE_P)
+		pq[0] = pq[1];
+	if (flags & DMA_PREP_PQ_DISABLE_Q)
+		pq[1] = pq[0];
+
+	/* the cleanup routine only sets bits on validate failure, it
+	 * does not clear bits on validate success... so clear it here
+	 */
+	*pqres = 0;
+
+	return src_cnt_flags(src_cnt, flags) > 8 ?
+		__ioat_prep_pq16_lock(chan, pqres, pq, src, src_cnt, scf, len,
+				       flags) :
+		__ioat_prep_pq_lock(chan, pqres, pq, src, src_cnt, scf, len,
+				     flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_pqxor(struct dma_chan *chan, dma_addr_t dst, dma_addr_t *src,
+		 unsigned int src_cnt, size_t len, unsigned long flags)
+{
+	unsigned char scf[src_cnt];
+	dma_addr_t pq[2];
+
+	memset(scf, 0, src_cnt);
+	pq[0] = dst;
+	flags |= DMA_PREP_PQ_DISABLE_Q;
+	pq[1] = dst; /* specify valid address for disabled result */
+
+	return src_cnt_flags(src_cnt, flags) > 8 ?
+		__ioat_prep_pq16_lock(chan, NULL, pq, src, src_cnt, scf, len,
+				       flags) :
+		__ioat_prep_pq_lock(chan, NULL, pq, src, src_cnt, scf, len,
+				     flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_pqxor_val(struct dma_chan *chan, dma_addr_t *src,
+		     unsigned int src_cnt, size_t len,
+		     enum sum_check_flags *result, unsigned long flags)
+{
+	unsigned char scf[src_cnt];
+	dma_addr_t pq[2];
+
+	/* the cleanup routine only sets bits on validate failure, it
+	 * does not clear bits on validate success... so clear it here
+	 */
+	*result = 0;
+
+	memset(scf, 0, src_cnt);
+	pq[0] = src[0];
+	flags |= DMA_PREP_PQ_DISABLE_Q;
+	pq[1] = pq[0]; /* specify valid address for disabled result */
+
+	return src_cnt_flags(src_cnt, flags) > 8 ?
+		__ioat_prep_pq16_lock(chan, result, pq, &src[1], src_cnt - 1,
+				       scf, len, flags) :
+		__ioat_prep_pq_lock(chan, result, pq, &src[1], src_cnt - 1,
+				     scf, len, flags);
+}
+
+struct dma_async_tx_descriptor *
+ioat_prep_interrupt_lock(struct dma_chan *c, unsigned long flags)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioat_ring_ent *desc;
+	struct ioat_dma_descriptor *hw;
+
+	if (ioat_check_space_lock(ioat_chan, 1) == 0)
+		desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head);
+	else
+		return NULL;
+
+	hw = desc->hw;
+	hw->ctl = 0;
+	hw->ctl_f.null = 1;
+	hw->ctl_f.int_en = 1;
+	hw->ctl_f.fence = !!(flags & DMA_PREP_FENCE);
+	hw->ctl_f.compl_write = 1;
+	hw->size = NULL_DESC_BUFFER_SIZE;
+	hw->src_addr = 0;
+	hw->dst_addr = 0;
+
+	desc->txd.flags = flags;
+	desc->len = 1;
+
+	dump_desc_dbg(ioat_chan, desc);
+
+	/* we leave the channel locked to ensure in order submission */
+	return &desc->txd;
+}
+