dmaengine: ioatdma: remove dma_v2.*

Clean out dma_v2 and remove ioat2 calls since we are moving everything
to just ioat.

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>

1 files changed, 661 insertions, 6 deletions

diff --git a/drivers/dma/ioat/dma.c b/drivers/dma/ioat/dma.c
index 3cf2639fb06a..02b5c04dea8a 100644
--- a/drivers/dma/ioat/dma.c
+++ b/drivers/dma/ioat/dma.c
@@ -41,6 +41,19 @@ int ioat_pending_level = 4;
 module_param(ioat_pending_level, int, 0644);
 MODULE_PARM_DESC(ioat_pending_level,
 		 "high-water mark for pushing ioat descriptors (default: 4)");
+int ioat_ring_alloc_order = 8;
+module_param(ioat_ring_alloc_order, int, 0644);
+MODULE_PARM_DESC(ioat_ring_alloc_order,
+		 "ioat+: allocate 2^n descriptors per channel (default: 8 max: 16)");
+static int ioat_ring_max_alloc_order = IOAT_MAX_ORDER;
+module_param(ioat_ring_max_alloc_order, int, 0644);
+MODULE_PARM_DESC(ioat_ring_max_alloc_order,
+		 "ioat+: upper limit for ring size (default: 16)");
+static char ioat_interrupt_style[32] = "msix";
+module_param_string(ioat_interrupt_style, ioat_interrupt_style,
+		    sizeof(ioat_interrupt_style), 0644);
+MODULE_PARM_DESC(ioat_interrupt_style,
+		 "set ioat interrupt style: msix (default), msi, intx");
 
 /**
  * ioat_dma_do_interrupt - handler used for single vector interrupt mode
@@ -314,12 +327,6 @@ out:
 	return err;
 }
 
-static char ioat_interrupt_style[32] = "msix";
-module_param_string(ioat_interrupt_style, ioat_interrupt_style,
-		    sizeof(ioat_interrupt_style), 0644);
-MODULE_PARM_DESC(ioat_interrupt_style,
-		 "set ioat interrupt style: msix (default), msi, intx");
-
 /**
  * ioat_dma_setup_interrupts - setup interrupt handler
  * @ioat_dma: ioat dma device
@@ -577,3 +584,651 @@ void ioat_dma_remove(struct ioatdma_device *ioat_dma)
 
 	INIT_LIST_HEAD(&dma->channels);
 }
+
+void __ioat_issue_pending(struct ioatdma_chan *ioat_chan)
+{
+	ioat_chan->dmacount += ioat_ring_pending(ioat_chan);
+	ioat_chan->issued = ioat_chan->head;
+	writew(ioat_chan->dmacount,
+	       ioat_chan->reg_base + IOAT_CHAN_DMACOUNT_OFFSET);
+	dev_dbg(to_dev(ioat_chan),
+		"%s: head: %#x tail: %#x issued: %#x count: %#x\n",
+		__func__, ioat_chan->head, ioat_chan->tail,
+		ioat_chan->issued, ioat_chan->dmacount);
+}
+
+void ioat_issue_pending(struct dma_chan *c)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+	if (ioat_ring_pending(ioat_chan)) {
+		spin_lock_bh(&ioat_chan->prep_lock);
+		__ioat_issue_pending(ioat_chan);
+		spin_unlock_bh(&ioat_chan->prep_lock);
+	}
+}
+
+/**
+ * ioat_update_pending - log pending descriptors
+ * @ioat: ioat+ channel
+ *
+ * Check if the number of unsubmitted descriptors has exceeded the
+ * watermark.  Called with prep_lock held
+ */
+static void ioat_update_pending(struct ioatdma_chan *ioat_chan)
+{
+	if (ioat_ring_pending(ioat_chan) > ioat_pending_level)
+		__ioat_issue_pending(ioat_chan);
+}
+
+static void __ioat_start_null_desc(struct ioatdma_chan *ioat_chan)
+{
+	struct ioat_ring_ent *desc;
+	struct ioat_dma_descriptor *hw;
+
+	if (ioat_ring_space(ioat_chan) < 1) {
+		dev_err(to_dev(ioat_chan),
+			"Unable to start null desc - ring full\n");
+		return;
+	}
+
+	dev_dbg(to_dev(ioat_chan),
+		"%s: head: %#x tail: %#x issued: %#x\n",
+		__func__, ioat_chan->head, ioat_chan->tail, ioat_chan->issued);
+	desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head);
+
+	hw = desc->hw;
+	hw->ctl = 0;
+	hw->ctl_f.null = 1;
+	hw->ctl_f.int_en = 1;
+	hw->ctl_f.compl_write = 1;
+	/* set size to non-zero value (channel returns error when size is 0) */
+	hw->size = NULL_DESC_BUFFER_SIZE;
+	hw->src_addr = 0;
+	hw->dst_addr = 0;
+	async_tx_ack(&desc->txd);
+	ioat_set_chainaddr(ioat_chan, desc->txd.phys);
+	dump_desc_dbg(ioat_chan, desc);
+	/* make sure descriptors are written before we submit */
+	wmb();
+	ioat_chan->head += 1;
+	__ioat_issue_pending(ioat_chan);
+}
+
+static void ioat_start_null_desc(struct ioatdma_chan *ioat_chan)
+{
+	spin_lock_bh(&ioat_chan->prep_lock);
+	__ioat_start_null_desc(ioat_chan);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+}
+
+void __ioat_restart_chan(struct ioatdma_chan *ioat_chan)
+{
+	/* set the tail to be re-issued */
+	ioat_chan->issued = ioat_chan->tail;
+	ioat_chan->dmacount = 0;
+	set_bit(IOAT_COMPLETION_PENDING, &ioat_chan->state);
+	mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+
+	dev_dbg(to_dev(ioat_chan),
+		"%s: head: %#x tail: %#x issued: %#x count: %#x\n",
+		__func__, ioat_chan->head, ioat_chan->tail,
+		ioat_chan->issued, ioat_chan->dmacount);
+
+	if (ioat_ring_pending(ioat_chan)) {
+		struct ioat_ring_ent *desc;
+
+		desc = ioat_get_ring_ent(ioat_chan, ioat_chan->tail);
+		ioat_set_chainaddr(ioat_chan, desc->txd.phys);
+		__ioat_issue_pending(ioat_chan);
+	} else
+		__ioat_start_null_desc(ioat_chan);
+}
+
+int ioat_quiesce(struct ioatdma_chan *ioat_chan, unsigned long tmo)
+{
+	unsigned long end = jiffies + tmo;
+	int err = 0;
+	u32 status;
+
+	status = ioat_chansts(ioat_chan);
+	if (is_ioat_active(status) || is_ioat_idle(status))
+		ioat_suspend(ioat_chan);
+	while (is_ioat_active(status) || is_ioat_idle(status)) {
+		if (tmo && time_after(jiffies, end)) {
+			err = -ETIMEDOUT;
+			break;
+		}
+		status = ioat_chansts(ioat_chan);
+		cpu_relax();
+	}
+
+	return err;
+}
+
+int ioat_reset_sync(struct ioatdma_chan *ioat_chan, unsigned long tmo)
+{
+	unsigned long end = jiffies + tmo;
+	int err = 0;
+
+	ioat_reset(ioat_chan);
+	while (ioat_reset_pending(ioat_chan)) {
+		if (end && time_after(jiffies, end)) {
+			err = -ETIMEDOUT;
+			break;
+		}
+		cpu_relax();
+	}
+
+	return err;
+}
+
+/**
+ * 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)
+{
+	struct ioatdma_chan *ioat_chan;
+	struct device *dev = &ioat_dma->pdev->dev;
+	struct dma_device *dma = &ioat_dma->dma_dev;
+	u8 xfercap_log;
+	int i;
+
+	INIT_LIST_HEAD(&dma->channels);
+	dma->chancnt = readb(ioat_dma->reg_base + IOAT_CHANCNT_OFFSET);
+	dma->chancnt &= 0x1f; /* bits [4:0] valid */
+	if (dma->chancnt > ARRAY_SIZE(ioat_dma->idx)) {
+		dev_warn(dev, "(%d) exceeds max supported channels (%zu)\n",
+			 dma->chancnt, ARRAY_SIZE(ioat_dma->idx));
+		dma->chancnt = ARRAY_SIZE(ioat_dma->idx);
+	}
+	xfercap_log = readb(ioat_dma->reg_base + IOAT_XFERCAP_OFFSET);
+	xfercap_log &= 0x1f; /* bits [4:0] valid */
+	if (xfercap_log == 0)
+		return 0;
+	dev_dbg(dev, "%s: xfercap = %d\n", __func__, 1 << xfercap_log);
+
+	for (i = 0; i < dma->chancnt; i++) {
+		ioat_chan = devm_kzalloc(dev, sizeof(*ioat_chan), GFP_KERNEL);
+		if (!ioat_chan)
+			break;
+
+		ioat_init_channel(ioat_dma, ioat_chan, i);
+		ioat_chan->xfercap_log = xfercap_log;
+		spin_lock_init(&ioat_chan->prep_lock);
+		if (ioat_dma->reset_hw(ioat_chan)) {
+			i = 0;
+			break;
+		}
+	}
+	dma->chancnt = i;
+	return i;
+}
+
+static dma_cookie_t ioat_tx_submit_unlock(struct dma_async_tx_descriptor *tx)
+{
+	struct dma_chan *c = tx->chan;
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	dma_cookie_t cookie;
+
+	cookie = dma_cookie_assign(tx);
+	dev_dbg(to_dev(ioat_chan), "%s: cookie: %d\n", __func__, cookie);
+
+	if (!test_and_set_bit(IOAT_CHAN_ACTIVE, &ioat_chan->state))
+		mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+
+	/* make descriptor updates visible before advancing ioat->head,
+	 * this is purposefully not smp_wmb() since we are also
+	 * publishing the descriptor updates to a dma device
+	 */
+	wmb();
+
+	ioat_chan->head += ioat_chan->produce;
+
+	ioat_update_pending(ioat_chan);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+
+	return cookie;
+}
+
+static struct ioat_ring_ent *
+ioat_alloc_ring_ent(struct dma_chan *chan, gfp_t flags)
+{
+	struct ioat_dma_descriptor *hw;
+	struct ioat_ring_ent *desc;
+	struct ioatdma_device *ioat_dma;
+	dma_addr_t phys;
+
+	ioat_dma = to_ioatdma_device(chan->device);
+	hw = pci_pool_alloc(ioat_dma->dma_pool, flags, &phys);
+	if (!hw)
+		return NULL;
+	memset(hw, 0, sizeof(*hw));
+
+	desc = kmem_cache_zalloc(ioat_cache, flags);
+	if (!desc) {
+		pci_pool_free(ioat_dma->dma_pool, hw, phys);
+		return NULL;
+	}
+
+	dma_async_tx_descriptor_init(&desc->txd, chan);
+	desc->txd.tx_submit = ioat_tx_submit_unlock;
+	desc->hw = hw;
+	desc->txd.phys = phys;
+	return desc;
+}
+
+static void
+ioat_free_ring_ent(struct ioat_ring_ent *desc, struct dma_chan *chan)
+{
+	struct ioatdma_device *ioat_dma;
+
+	ioat_dma = to_ioatdma_device(chan->device);
+	pci_pool_free(ioat_dma->dma_pool, desc->hw, desc->txd.phys);
+	kmem_cache_free(ioat_cache, desc);
+}
+
+static struct ioat_ring_ent **
+ioat_alloc_ring(struct dma_chan *c, int order, gfp_t flags)
+{
+	struct ioat_ring_ent **ring;
+	int descs = 1 << order;
+	int i;
+
+	if (order > ioat_get_max_alloc_order())
+		return NULL;
+
+	/* allocate the array to hold the software ring */
+	ring = kcalloc(descs, sizeof(*ring), flags);
+	if (!ring)
+		return NULL;
+	for (i = 0; i < descs; i++) {
+		ring[i] = ioat_alloc_ring_ent(c, flags);
+		if (!ring[i]) {
+			while (i--)
+				ioat_free_ring_ent(ring[i], c);
+			kfree(ring);
+			return NULL;
+		}
+		set_desc_id(ring[i], i);
+	}
+
+	/* link descs */
+	for (i = 0; i < descs-1; i++) {
+		struct ioat_ring_ent *next = ring[i+1];
+		struct ioat_dma_descriptor *hw = ring[i]->hw;
+
+		hw->next = next->txd.phys;
+	}
+	ring[i]->hw->next = ring[0]->txd.phys;
+
+	return ring;
+}
+
+/**
+ * ioat_free_chan_resources - release all the descriptors
+ * @chan: the channel to be cleaned
+ */
+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;
+	struct ioat_ring_ent *desc;
+	const int total_descs = 1 << ioat_chan->alloc_order;
+	int descs;
+	int i;
+
+	/* Before freeing channel resources first check
+	 * if they have been previously allocated for this channel.
+	 */
+	if (!ioat_chan->ring)
+		return;
+
+	ioat_stop(ioat_chan);
+	ioat_dma->reset_hw(ioat_chan);
+
+	spin_lock_bh(&ioat_chan->cleanup_lock);
+	spin_lock_bh(&ioat_chan->prep_lock);
+	descs = ioat_ring_space(ioat_chan);
+	dev_dbg(to_dev(ioat_chan), "freeing %d idle descriptors\n", descs);
+	for (i = 0; i < descs; i++) {
+		desc = ioat_get_ring_ent(ioat_chan, ioat_chan->head + i);
+		ioat_free_ring_ent(desc, c);
+	}
+
+	if (descs < total_descs)
+		dev_err(to_dev(ioat_chan), "Freeing %d in use descriptors!\n",
+			total_descs - descs);
+
+	for (i = 0; i < total_descs - descs; i++) {
+		desc = ioat_get_ring_ent(ioat_chan, ioat_chan->tail + i);
+		dump_desc_dbg(ioat_chan, desc);
+		ioat_free_ring_ent(desc, c);
+	}
+
+	kfree(ioat_chan->ring);
+	ioat_chan->ring = NULL;
+	ioat_chan->alloc_order = 0;
+	pci_pool_free(ioat_dma->completion_pool, ioat_chan->completion,
+		      ioat_chan->completion_dma);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+	spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+	ioat_chan->last_completion = 0;
+	ioat_chan->completion_dma = 0;
+	ioat_chan->dmacount = 0;
+}
+
+/* ioat_alloc_chan_resources - allocate/initialize ioat descriptor ring
+ * @chan: channel to be initialized
+ */
+int ioat_alloc_chan_resources(struct dma_chan *c)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+	struct ioat_ring_ent **ring;
+	u64 status;
+	int order;
+	int i = 0;
+	u32 chanerr;
+
+	/* have we already been set up? */
+	if (ioat_chan->ring)
+		return 1 << ioat_chan->alloc_order;
+
+	/* Setup register to interrupt and write completion status on error */
+	writew(IOAT_CHANCTRL_RUN, ioat_chan->reg_base + IOAT_CHANCTRL_OFFSET);
+
+	/* allocate a completion writeback area */
+	/* doing 2 32bit writes to mmio since 1 64b write doesn't work */
+	ioat_chan->completion =
+		pci_pool_alloc(ioat_chan->ioat_dma->completion_pool,
+			       GFP_KERNEL, &ioat_chan->completion_dma);
+	if (!ioat_chan->completion)
+		return -ENOMEM;
+
+	memset(ioat_chan->completion, 0, sizeof(*ioat_chan->completion));
+	writel(((u64)ioat_chan->completion_dma) & 0x00000000FFFFFFFF,
+	       ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_LOW);
+	writel(((u64)ioat_chan->completion_dma) >> 32,
+	       ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH);
+
+	order = ioat_get_alloc_order();
+	ring = ioat_alloc_ring(c, order, GFP_KERNEL);
+	if (!ring)
+		return -ENOMEM;
+
+	spin_lock_bh(&ioat_chan->cleanup_lock);
+	spin_lock_bh(&ioat_chan->prep_lock);
+	ioat_chan->ring = ring;
+	ioat_chan->head = 0;
+	ioat_chan->issued = 0;
+	ioat_chan->tail = 0;
+	ioat_chan->alloc_order = order;
+	set_bit(IOAT_RUN, &ioat_chan->state);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+	spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+	ioat_start_null_desc(ioat_chan);
+
+	/* check that we got off the ground */
+	do {
+		udelay(1);
+		status = ioat_chansts(ioat_chan);
+	} while (i++ < 20 && !is_ioat_active(status) && !is_ioat_idle(status));
+
+	if (is_ioat_active(status) || is_ioat_idle(status))
+		return 1 << ioat_chan->alloc_order;
+
+	chanerr = readl(ioat_chan->reg_base + IOAT_CHANERR_OFFSET);
+
+	dev_WARN(to_dev(ioat_chan),
+		"failed to start channel chanerr: %#x\n", chanerr);
+	ioat_free_chan_resources(c);
+	return -EFAULT;
+}
+
+bool reshape_ring(struct ioatdma_chan *ioat_chan, int order)
+{
+	/* reshape differs from normal ring allocation in that we want
+	 * to allocate a new software ring while only
+	 * extending/truncating the hardware ring
+	 */
+	struct dma_chan *c = &ioat_chan->dma_chan;
+	const u32 curr_size = ioat_ring_size(ioat_chan);
+	const u16 active = ioat_ring_active(ioat_chan);
+	const u32 new_size = 1 << order;
+	struct ioat_ring_ent **ring;
+	u32 i;
+
+	if (order > ioat_get_max_alloc_order())
+		return false;
+
+	/* double check that we have at least 1 free descriptor */
+	if (active == curr_size)
+		return false;
+
+	/* when shrinking, verify that we can hold the current active
+	 * set in the new ring
+	 */
+	if (active >= new_size)
+		return false;
+
+	/* allocate the array to hold the software ring */
+	ring = kcalloc(new_size, sizeof(*ring), GFP_NOWAIT);
+	if (!ring)
+		return false;
+
+	/* allocate/trim descriptors as needed */
+	if (new_size > curr_size) {
+		/* copy current descriptors to the new ring */
+		for (i = 0; i < curr_size; i++) {
+			u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
+			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+			ring[new_idx] = ioat_chan->ring[curr_idx];
+			set_desc_id(ring[new_idx], new_idx);
+		}
+
+		/* add new descriptors to the ring */
+		for (i = curr_size; i < new_size; i++) {
+			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+			ring[new_idx] = ioat_alloc_ring_ent(c, GFP_NOWAIT);
+			if (!ring[new_idx]) {
+				while (i--) {
+					u16 new_idx = (ioat_chan->tail+i) &
+						       (new_size-1);
+
+					ioat_free_ring_ent(ring[new_idx], c);
+				}
+				kfree(ring);
+				return false;
+			}
+			set_desc_id(ring[new_idx], new_idx);
+		}
+
+		/* hw link new descriptors */
+		for (i = curr_size-1; i < new_size; i++) {
+			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+			struct ioat_ring_ent *next =
+				ring[(new_idx+1) & (new_size-1)];
+			struct ioat_dma_descriptor *hw = ring[new_idx]->hw;
+
+			hw->next = next->txd.phys;
+		}
+	} else {
+		struct ioat_dma_descriptor *hw;
+		struct ioat_ring_ent *next;
+
+		/* copy current descriptors to the new ring, dropping the
+		 * removed descriptors
+		 */
+		for (i = 0; i < new_size; i++) {
+			u16 curr_idx = (ioat_chan->tail+i) & (curr_size-1);
+			u16 new_idx = (ioat_chan->tail+i) & (new_size-1);
+
+			ring[new_idx] = ioat_chan->ring[curr_idx];
+			set_desc_id(ring[new_idx], new_idx);
+		}
+
+		/* free deleted descriptors */
+		for (i = new_size; i < curr_size; i++) {
+			struct ioat_ring_ent *ent;
+
+			ent = ioat_get_ring_ent(ioat_chan, ioat_chan->tail+i);
+			ioat_free_ring_ent(ent, c);
+		}
+
+		/* fix up hardware ring */
+		hw = ring[(ioat_chan->tail+new_size-1) & (new_size-1)]->hw;
+		next = ring[(ioat_chan->tail+new_size) & (new_size-1)];
+		hw->next = next->txd.phys;
+	}
+
+	dev_dbg(to_dev(ioat_chan), "%s: allocated %d descriptors\n",
+		__func__, new_size);
+
+	kfree(ioat_chan->ring);
+	ioat_chan->ring = ring;
+	ioat_chan->alloc_order = order;
+
+	return true;
+}
+
+/**
+ * ioat_check_space_lock - verify space and grab ring producer lock
+ * @ioat: ioat,3 channel (ring) to operate on
+ * @num_descs: allocation length
+ */
+int ioat_check_space_lock(struct ioatdma_chan *ioat_chan, int num_descs)
+{
+	bool retry;
+
+ retry:
+	spin_lock_bh(&ioat_chan->prep_lock);
+	/* never allow the last descriptor to be consumed, we need at
+	 * least one free at all times to allow for on-the-fly ring
+	 * resizing.
+	 */
+	if (likely(ioat_ring_space(ioat_chan) > num_descs)) {
+		dev_dbg(to_dev(ioat_chan), "%s: num_descs: %d (%x:%x:%x)\n",
+			__func__, num_descs, ioat_chan->head,
+			ioat_chan->tail, ioat_chan->issued);
+		ioat_chan->produce = num_descs;
+		return 0;  /* with ioat->prep_lock held */
+	}
+	retry = test_and_set_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+
+	/* is another cpu already trying to expand the ring? */
+	if (retry)
+		goto retry;
+
+	spin_lock_bh(&ioat_chan->cleanup_lock);
+	spin_lock_bh(&ioat_chan->prep_lock);
+	retry = reshape_ring(ioat_chan, ioat_chan->alloc_order + 1);
+	clear_bit(IOAT_RESHAPE_PENDING, &ioat_chan->state);
+	spin_unlock_bh(&ioat_chan->prep_lock);
+	spin_unlock_bh(&ioat_chan->cleanup_lock);
+
+	/* if we were able to expand the ring retry the allocation */
+	if (retry)
+		goto retry;
+
+	dev_dbg_ratelimited(to_dev(ioat_chan),
+			    "%s: ring full! num_descs: %d (%x:%x:%x)\n",
+			    __func__, num_descs, ioat_chan->head,
+			    ioat_chan->tail, ioat_chan->issued);
+
+	/* progress reclaim in the allocation failure case we may be
+	 * called under bh_disabled so we need to trigger the timer
+	 * event directly
+	 */
+	if (time_is_before_jiffies(ioat_chan->timer.expires)
+	    && timer_pending(&ioat_chan->timer)) {
+		struct ioatdma_device *ioat_dma = ioat_chan->ioat_dma;
+
+		mod_timer(&ioat_chan->timer, jiffies + COMPLETION_TIMEOUT);
+		ioat_dma->timer_fn((unsigned long)ioat_chan);
+	}
+
+	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;
+}
+
+static ssize_t ring_size_show(struct dma_chan *c, char *page)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+	return sprintf(page, "%d\n", (1 << ioat_chan->alloc_order) & ~1);
+}
+static struct ioat_sysfs_entry ring_size_attr = __ATTR_RO(ring_size);
+
+static ssize_t ring_active_show(struct dma_chan *c, char *page)
+{
+	struct ioatdma_chan *ioat_chan = to_ioat_chan(c);
+
+	/* ...taken outside the lock, no need to be precise */
+	return sprintf(page, "%d\n", ioat_ring_active(ioat_chan));
+}
+static struct ioat_sysfs_entry ring_active_attr = __ATTR_RO(ring_active);
+
+static struct attribute *ioat_attrs[] = {
+	&ring_size_attr.attr,
+	&ring_active_attr.attr,
+	&ioat_cap_attr.attr,
+	&ioat_version_attr.attr,
+	NULL,
+};
+
+struct kobj_type ioat_ktype = {
+	.sysfs_ops = &ioat_sysfs_ops,
+	.default_attrs = ioat_attrs,
+};