Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1960 insertions, 0 deletions

diff --git a/drivers/misc/mic/scif/scif_dma.c b/drivers/misc/mic/scif/scif_dma.c
new file mode 100644
index 000000000..6369aeaa7
--- /dev/null
+++ b/drivers/misc/mic/scif/scif_dma.c
@@ -0,0 +1,1960 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2015 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms 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.
+ *
+ * Intel SCIF driver.
+ *
+ */
+#include "scif_main.h"
+#include "scif_map.h"
+
+/*
+ * struct scif_dma_comp_cb - SCIF DMA completion callback
+ *
+ * @dma_completion_func: DMA completion callback
+ * @cb_cookie: DMA completion callback cookie
+ * @temp_buf: Temporary buffer
+ * @temp_buf_to_free: Temporary buffer to be freed
+ * @is_cache: Is a kmem_cache allocated buffer
+ * @dst_offset: Destination registration offset
+ * @dst_window: Destination registration window
+ * @len: Length of the temp buffer
+ * @temp_phys: DMA address of the temp buffer
+ * @sdev: The SCIF device
+ * @header_padding: padding for cache line alignment
+ */
+struct scif_dma_comp_cb {
+	void (*dma_completion_func)(void *cookie);
+	void *cb_cookie;
+	u8 *temp_buf;
+	u8 *temp_buf_to_free;
+	bool is_cache;
+	s64 dst_offset;
+	struct scif_window *dst_window;
+	size_t len;
+	dma_addr_t temp_phys;
+	struct scif_dev *sdev;
+	int header_padding;
+};
+
+/**
+ * struct scif_copy_work - Work for DMA copy
+ *
+ * @src_offset: Starting source offset
+ * @dst_offset: Starting destination offset
+ * @src_window: Starting src registered window
+ * @dst_window: Starting dst registered window
+ * @loopback: true if this is a loopback DMA transfer
+ * @len: Length of the transfer
+ * @comp_cb: DMA copy completion callback
+ * @remote_dev: The remote SCIF peer device
+ * @fence_type: polling or interrupt based
+ * @ordered: is this a tail byte ordered DMA transfer
+ */
+struct scif_copy_work {
+	s64 src_offset;
+	s64 dst_offset;
+	struct scif_window *src_window;
+	struct scif_window *dst_window;
+	int loopback;
+	size_t len;
+	struct scif_dma_comp_cb   *comp_cb;
+	struct scif_dev	*remote_dev;
+	int fence_type;
+	bool ordered;
+};
+
+/**
+ * scif_reserve_dma_chan:
+ * @ep: Endpoint Descriptor.
+ *
+ * This routine reserves a DMA channel for a particular
+ * endpoint. All DMA transfers for an endpoint are always
+ * programmed on the same DMA channel.
+ */
+int scif_reserve_dma_chan(struct scif_endpt *ep)
+{
+	int err = 0;
+	struct scif_dev *scifdev;
+	struct scif_hw_dev *sdev;
+	struct dma_chan *chan;
+
+	/* Loopback DMAs are not supported on the management node */
+	if (!scif_info.nodeid && scifdev_self(ep->remote_dev))
+		return 0;
+	if (scif_info.nodeid)
+		scifdev = &scif_dev[0];
+	else
+		scifdev = ep->remote_dev;
+	sdev = scifdev->sdev;
+	if (!sdev->num_dma_ch)
+		return -ENODEV;
+	chan = sdev->dma_ch[scifdev->dma_ch_idx];
+	scifdev->dma_ch_idx = (scifdev->dma_ch_idx + 1) % sdev->num_dma_ch;
+	mutex_lock(&ep->rma_info.rma_lock);
+	ep->rma_info.dma_chan = chan;
+	mutex_unlock(&ep->rma_info.rma_lock);
+	return err;
+}
+
+#ifdef CONFIG_MMU_NOTIFIER
+/**
+ * scif_rma_destroy_tcw:
+ *
+ * This routine destroys temporary cached windows
+ */
+static
+void __scif_rma_destroy_tcw(struct scif_mmu_notif *mmn,
+			    u64 start, u64 len)
+{
+	struct list_head *item, *tmp;
+	struct scif_window *window;
+	u64 start_va, end_va;
+	u64 end = start + len;
+
+	if (end <= start)
+		return;
+
+	list_for_each_safe(item, tmp, &mmn->tc_reg_list) {
+		window = list_entry(item, struct scif_window, list);
+		if (!len)
+			break;
+		start_va = window->va_for_temp;
+		end_va = start_va + (window->nr_pages << PAGE_SHIFT);
+		if (start < start_va && end <= start_va)
+			break;
+		if (start >= end_va)
+			continue;
+		__scif_rma_destroy_tcw_helper(window);
+	}
+}
+
+static void scif_rma_destroy_tcw(struct scif_mmu_notif *mmn, u64 start, u64 len)
+{
+	struct scif_endpt *ep = mmn->ep;
+
+	spin_lock(&ep->rma_info.tc_lock);
+	__scif_rma_destroy_tcw(mmn, start, len);
+	spin_unlock(&ep->rma_info.tc_lock);
+}
+
+static void scif_rma_destroy_tcw_ep(struct scif_endpt *ep)
+{
+	struct list_head *item, *tmp;
+	struct scif_mmu_notif *mmn;
+
+	list_for_each_safe(item, tmp, &ep->rma_info.mmn_list) {
+		mmn = list_entry(item, struct scif_mmu_notif, list);
+		scif_rma_destroy_tcw(mmn, 0, ULONG_MAX);
+	}
+}
+
+static void __scif_rma_destroy_tcw_ep(struct scif_endpt *ep)
+{
+	struct list_head *item, *tmp;
+	struct scif_mmu_notif *mmn;
+
+	spin_lock(&ep->rma_info.tc_lock);
+	list_for_each_safe(item, tmp, &ep->rma_info.mmn_list) {
+		mmn = list_entry(item, struct scif_mmu_notif, list);
+		__scif_rma_destroy_tcw(mmn, 0, ULONG_MAX);
+	}
+	spin_unlock(&ep->rma_info.tc_lock);
+}
+
+static bool scif_rma_tc_can_cache(struct scif_endpt *ep, size_t cur_bytes)
+{
+	if ((cur_bytes >> PAGE_SHIFT) > scif_info.rma_tc_limit)
+		return false;
+	if ((atomic_read(&ep->rma_info.tcw_total_pages)
+			+ (cur_bytes >> PAGE_SHIFT)) >
+			scif_info.rma_tc_limit) {
+		dev_info(scif_info.mdev.this_device,
+			 "%s %d total=%d, current=%zu reached max\n",
+			 __func__, __LINE__,
+			 atomic_read(&ep->rma_info.tcw_total_pages),
+			 (1 + (cur_bytes >> PAGE_SHIFT)));
+		scif_rma_destroy_tcw_invalid();
+		__scif_rma_destroy_tcw_ep(ep);
+	}
+	return true;
+}
+
+static void scif_mmu_notifier_release(struct mmu_notifier *mn,
+				      struct mm_struct *mm)
+{
+	struct scif_mmu_notif	*mmn;
+
+	mmn = container_of(mn, struct scif_mmu_notif, ep_mmu_notifier);
+	scif_rma_destroy_tcw(mmn, 0, ULONG_MAX);
+	schedule_work(&scif_info.misc_work);
+}
+
+static int scif_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
+						     struct mm_struct *mm,
+						     unsigned long start,
+						     unsigned long end,
+						     bool blockable)
+{
+	struct scif_mmu_notif	*mmn;
+
+	mmn = container_of(mn, struct scif_mmu_notif, ep_mmu_notifier);
+	scif_rma_destroy_tcw(mmn, start, end - start);
+
+	return 0;
+}
+
+static void scif_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn,
+						   struct mm_struct *mm,
+						   unsigned long start,
+						   unsigned long end)
+{
+	/*
+	 * Nothing to do here, everything needed was done in
+	 * invalidate_range_start.
+	 */
+}
+
+static const struct mmu_notifier_ops scif_mmu_notifier_ops = {
+	.release = scif_mmu_notifier_release,
+	.clear_flush_young = NULL,
+	.invalidate_range_start = scif_mmu_notifier_invalidate_range_start,
+	.invalidate_range_end = scif_mmu_notifier_invalidate_range_end};
+
+static void scif_ep_unregister_mmu_notifier(struct scif_endpt *ep)
+{
+	struct scif_endpt_rma_info *rma = &ep->rma_info;
+	struct scif_mmu_notif *mmn = NULL;
+	struct list_head *item, *tmp;
+
+	mutex_lock(&ep->rma_info.mmn_lock);
+	list_for_each_safe(item, tmp, &rma->mmn_list) {
+		mmn = list_entry(item, struct scif_mmu_notif, list);
+		mmu_notifier_unregister(&mmn->ep_mmu_notifier, mmn->mm);
+		list_del(item);
+		kfree(mmn);
+	}
+	mutex_unlock(&ep->rma_info.mmn_lock);
+}
+
+static void scif_init_mmu_notifier(struct scif_mmu_notif *mmn,
+				   struct mm_struct *mm, struct scif_endpt *ep)
+{
+	mmn->ep = ep;
+	mmn->mm = mm;
+	mmn->ep_mmu_notifier.ops = &scif_mmu_notifier_ops;
+	INIT_LIST_HEAD(&mmn->list);
+	INIT_LIST_HEAD(&mmn->tc_reg_list);
+}
+
+static struct scif_mmu_notif *
+scif_find_mmu_notifier(struct mm_struct *mm, struct scif_endpt_rma_info *rma)
+{
+	struct scif_mmu_notif *mmn;
+
+	list_for_each_entry(mmn, &rma->mmn_list, list)
+		if (mmn->mm == mm)
+			return mmn;
+	return NULL;
+}
+
+static struct scif_mmu_notif *
+scif_add_mmu_notifier(struct mm_struct *mm, struct scif_endpt *ep)
+{
+	struct scif_mmu_notif *mmn
+		 = kzalloc(sizeof(*mmn), GFP_KERNEL);
+
+	if (!mmn)
+		return ERR_PTR(-ENOMEM);
+
+	scif_init_mmu_notifier(mmn, current->mm, ep);
+	if (mmu_notifier_register(&mmn->ep_mmu_notifier, current->mm)) {
+		kfree(mmn);
+		return ERR_PTR(-EBUSY);
+	}
+	list_add(&mmn->list, &ep->rma_info.mmn_list);
+	return mmn;
+}
+
+/*
+ * Called from the misc thread to destroy temporary cached windows and
+ * unregister the MMU notifier for the SCIF endpoint.
+ */
+void scif_mmu_notif_handler(struct work_struct *work)
+{
+	struct list_head *pos, *tmpq;
+	struct scif_endpt *ep;
+restart:
+	scif_rma_destroy_tcw_invalid();
+	spin_lock(&scif_info.rmalock);
+	list_for_each_safe(pos, tmpq, &scif_info.mmu_notif_cleanup) {
+		ep = list_entry(pos, struct scif_endpt, mmu_list);
+		list_del(&ep->mmu_list);
+		spin_unlock(&scif_info.rmalock);
+		scif_rma_destroy_tcw_ep(ep);
+		scif_ep_unregister_mmu_notifier(ep);
+		goto restart;
+	}
+	spin_unlock(&scif_info.rmalock);
+}
+
+static bool scif_is_set_reg_cache(int flags)
+{
+	return !!(flags & SCIF_RMA_USECACHE);
+}
+#else
+static struct scif_mmu_notif *
+scif_find_mmu_notifier(struct mm_struct *mm,
+		       struct scif_endpt_rma_info *rma)
+{
+	return NULL;
+}
+
+static struct scif_mmu_notif *
+scif_add_mmu_notifier(struct mm_struct *mm, struct scif_endpt *ep)
+{
+	return NULL;
+}
+
+void scif_mmu_notif_handler(struct work_struct *work)
+{
+}
+
+static bool scif_is_set_reg_cache(int flags)
+{
+	return false;
+}
+
+static bool scif_rma_tc_can_cache(struct scif_endpt *ep, size_t cur_bytes)
+{
+	return false;
+}
+#endif
+
+/**
+ * scif_register_temp:
+ * @epd: End Point Descriptor.
+ * @addr: virtual address to/from which to copy
+ * @len: length of range to copy
+ * @out_offset: computed offset returned by reference.
+ * @out_window: allocated registered window returned by reference.
+ *
+ * Create a temporary registered window. The peer will not know about this
+ * window. This API is used for scif_vreadfrom()/scif_vwriteto() API's.
+ */
+static int
+scif_register_temp(scif_epd_t epd, unsigned long addr, size_t len, int prot,
+		   off_t *out_offset, struct scif_window **out_window)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	int err;
+	scif_pinned_pages_t pinned_pages;
+	size_t aligned_len;
+
+	aligned_len = ALIGN(len, PAGE_SIZE);
+
+	err = __scif_pin_pages((void *)(addr & PAGE_MASK),
+			       aligned_len, &prot, 0, &pinned_pages);
+	if (err)
+		return err;
+
+	pinned_pages->prot = prot;
+
+	/* Compute the offset for this registration */
+	err = scif_get_window_offset(ep, 0, 0,
+				     aligned_len >> PAGE_SHIFT,
+				     (s64 *)out_offset);
+	if (err)
+		goto error_unpin;
+
+	/* Allocate and prepare self registration window */
+	*out_window = scif_create_window(ep, aligned_len >> PAGE_SHIFT,
+					*out_offset, true);
+	if (!*out_window) {
+		scif_free_window_offset(ep, NULL, *out_offset);
+		err = -ENOMEM;
+		goto error_unpin;
+	}
+
+	(*out_window)->pinned_pages = pinned_pages;
+	(*out_window)->nr_pages = pinned_pages->nr_pages;
+	(*out_window)->prot = pinned_pages->prot;
+
+	(*out_window)->va_for_temp = addr & PAGE_MASK;
+	err = scif_map_window(ep->remote_dev, *out_window);
+	if (err) {
+		/* Something went wrong! Rollback */
+		scif_destroy_window(ep, *out_window);
+		*out_window = NULL;
+	} else {
+		*out_offset |= (addr - (*out_window)->va_for_temp);
+	}
+	return err;
+error_unpin:
+	if (err)
+		dev_err(&ep->remote_dev->sdev->dev,
+			"%s %d err %d\n", __func__, __LINE__, err);
+	scif_unpin_pages(pinned_pages);
+	return err;
+}
+
+#define SCIF_DMA_TO (3 * HZ)
+
+/*
+ * scif_sync_dma - Program a DMA without an interrupt descriptor
+ *
+ * @dev - The address of the pointer to the device instance used
+ * for DMA registration.
+ * @chan - DMA channel to be used.
+ * @sync_wait: Wait for DMA to complete?
+ *
+ * Return 0 on success and -errno on error.
+ */
+static int scif_sync_dma(struct scif_hw_dev *sdev, struct dma_chan *chan,
+			 bool sync_wait)
+{
+	int err = 0;
+	struct dma_async_tx_descriptor *tx = NULL;
+	enum dma_ctrl_flags flags = DMA_PREP_FENCE;
+	dma_cookie_t cookie;
+	struct dma_device *ddev;
+
+	if (!chan) {
+		err = -EIO;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		return err;
+	}
+	ddev = chan->device;
+
+	tx = ddev->device_prep_dma_memcpy(chan, 0, 0, 0, flags);
+	if (!tx) {
+		err = -ENOMEM;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+	cookie = tx->tx_submit(tx);
+
+	if (dma_submit_error(cookie)) {
+		err = -ENOMEM;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+	if (!sync_wait) {
+		dma_async_issue_pending(chan);
+	} else {
+		if (dma_sync_wait(chan, cookie) == DMA_COMPLETE) {
+			err = 0;
+		} else {
+			err = -EIO;
+			dev_err(&sdev->dev, "%s %d err %d\n",
+				__func__, __LINE__, err);
+		}
+	}
+release:
+	return err;
+}
+
+static void scif_dma_callback(void *arg)
+{
+	struct completion *done = (struct completion *)arg;
+
+	complete(done);
+}
+
+#define SCIF_DMA_SYNC_WAIT true
+#define SCIF_DMA_POLL BIT(0)
+#define SCIF_DMA_INTR BIT(1)
+
+/*
+ * scif_async_dma - Program a DMA with an interrupt descriptor
+ *
+ * @dev - The address of the pointer to the device instance used
+ * for DMA registration.
+ * @chan - DMA channel to be used.
+ * Return 0 on success and -errno on error.
+ */
+static int scif_async_dma(struct scif_hw_dev *sdev, struct dma_chan *chan)
+{
+	int err = 0;
+	struct dma_device *ddev;
+	struct dma_async_tx_descriptor *tx = NULL;
+	enum dma_ctrl_flags flags = DMA_PREP_INTERRUPT | DMA_PREP_FENCE;
+	DECLARE_COMPLETION_ONSTACK(done_wait);
+	dma_cookie_t cookie;
+	enum dma_status status;
+
+	if (!chan) {
+		err = -EIO;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		return err;
+	}
+	ddev = chan->device;
+
+	tx = ddev->device_prep_dma_memcpy(chan, 0, 0, 0, flags);
+	if (!tx) {
+		err = -ENOMEM;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+	reinit_completion(&done_wait);
+	tx->callback = scif_dma_callback;
+	tx->callback_param = &done_wait;
+	cookie = tx->tx_submit(tx);
+
+	if (dma_submit_error(cookie)) {
+		err = -ENOMEM;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+	dma_async_issue_pending(chan);
+
+	err = wait_for_completion_timeout(&done_wait, SCIF_DMA_TO);
+	if (!err) {
+		err = -EIO;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+	err = 0;
+	status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);
+	if (status != DMA_COMPLETE) {
+		err = -EIO;
+		dev_err(&sdev->dev, "%s %d err %d\n",
+			__func__, __LINE__, err);
+		goto release;
+	}
+release:
+	return err;
+}
+
+/*
+ * scif_drain_dma_poll - Drain all outstanding DMA operations for a particular
+ * DMA channel via polling.
+ *
+ * @sdev - The SCIF device
+ * @chan - DMA channel
+ * Return 0 on success and -errno on error.
+ */
+static int scif_drain_dma_poll(struct scif_hw_dev *sdev, struct dma_chan *chan)
+{
+	if (!chan)
+		return -EINVAL;
+	return scif_sync_dma(sdev, chan, SCIF_DMA_SYNC_WAIT);
+}
+
+/*
+ * scif_drain_dma_intr - Drain all outstanding DMA operations for a particular
+ * DMA channel via interrupt based blocking wait.
+ *
+ * @sdev - The SCIF device
+ * @chan - DMA channel
+ * Return 0 on success and -errno on error.
+ */
+int scif_drain_dma_intr(struct scif_hw_dev *sdev, struct dma_chan *chan)
+{
+	if (!chan)
+		return -EINVAL;
+	return scif_async_dma(sdev, chan);
+}
+
+/**
+ * scif_rma_destroy_windows:
+ *
+ * This routine destroys all windows queued for cleanup
+ */
+void scif_rma_destroy_windows(void)
+{
+	struct list_head *item, *tmp;
+	struct scif_window *window;
+	struct scif_endpt *ep;
+	struct dma_chan *chan;
+
+	might_sleep();
+restart:
+	spin_lock(&scif_info.rmalock);
+	list_for_each_safe(item, tmp, &scif_info.rma) {
+		window = list_entry(item, struct scif_window,
+				    list);
+		ep = (struct scif_endpt *)window->ep;
+		chan = ep->rma_info.dma_chan;
+
+		list_del_init(&window->list);
+		spin_unlock(&scif_info.rmalock);
+		if (!chan || !scifdev_alive(ep) ||
+		    !scif_drain_dma_intr(ep->remote_dev->sdev,
+					 ep->rma_info.dma_chan))
+			/* Remove window from global list */
+			window->unreg_state = OP_COMPLETED;
+		else
+			dev_warn(&ep->remote_dev->sdev->dev,
+				 "DMA engine hung?\n");
+		if (window->unreg_state == OP_COMPLETED) {
+			if (window->type == SCIF_WINDOW_SELF)
+				scif_destroy_window(ep, window);
+			else
+				scif_destroy_remote_window(window);
+			atomic_dec(&ep->rma_info.tw_refcount);
+		}
+		goto restart;
+	}
+	spin_unlock(&scif_info.rmalock);
+}
+
+/**
+ * scif_rma_destroy_tcw:
+ *
+ * This routine destroys temporary cached registered windows
+ * which have been queued for cleanup.
+ */
+void scif_rma_destroy_tcw_invalid(void)
+{
+	struct list_head *item, *tmp;
+	struct scif_window *window;
+	struct scif_endpt *ep;
+	struct dma_chan *chan;
+
+	might_sleep();
+restart:
+	spin_lock(&scif_info.rmalock);
+	list_for_each_safe(item, tmp, &scif_info.rma_tc) {
+		window = list_entry(item, struct scif_window, list);
+		ep = (struct scif_endpt *)window->ep;
+		chan = ep->rma_info.dma_chan;
+		list_del_init(&window->list);
+		spin_unlock(&scif_info.rmalock);
+		mutex_lock(&ep->rma_info.rma_lock);
+		if (!chan || !scifdev_alive(ep) ||
+		    !scif_drain_dma_intr(ep->remote_dev->sdev,
+					 ep->rma_info.dma_chan)) {
+			atomic_sub(window->nr_pages,
+				   &ep->rma_info.tcw_total_pages);
+			scif_destroy_window(ep, window);
+			atomic_dec(&ep->rma_info.tcw_refcount);
+		} else {
+			dev_warn(&ep->remote_dev->sdev->dev,
+				 "DMA engine hung?\n");
+		}
+		mutex_unlock(&ep->rma_info.rma_lock);
+		goto restart;
+	}
+	spin_unlock(&scif_info.rmalock);
+}
+
+static inline
+void *_get_local_va(off_t off, struct scif_window *window, size_t len)
+{
+	int page_nr = (off - window->offset) >> PAGE_SHIFT;
+	off_t page_off = off & ~PAGE_MASK;
+	void *va = NULL;
+
+	if (window->type == SCIF_WINDOW_SELF) {
+		struct page **pages = window->pinned_pages->pages;
+
+		va = page_address(pages[page_nr]) + page_off;
+	}
+	return va;
+}
+
+static inline
+void *ioremap_remote(off_t off, struct scif_window *window,
+		     size_t len, struct scif_dev *dev,
+		     struct scif_window_iter *iter)
+{
+	dma_addr_t phys = scif_off_to_dma_addr(window, off, NULL, iter);
+
+	/*
+	 * If the DMA address is not card relative then we need the DMA
+	 * addresses to be an offset into the bar. The aperture base was already
+	 * added so subtract it here since scif_ioremap is going to add it again
+	 */
+	if (!scifdev_self(dev) && window->type == SCIF_WINDOW_PEER &&
+	    dev->sdev->aper && !dev->sdev->card_rel_da)
+		phys = phys - dev->sdev->aper->pa;
+	return scif_ioremap(phys, len, dev);
+}
+
+static inline void
+iounmap_remote(void *virt, size_t size, struct scif_copy_work *work)
+{
+	scif_iounmap(virt, size, work->remote_dev);
+}
+
+/*
+ * Takes care of ordering issue caused by
+ * 1. Hardware:  Only in the case of cpu copy from mgmt node to card
+ * because of WC memory.
+ * 2. Software: If memcpy reorders copy instructions for optimization.
+ * This could happen at both mgmt node and card.
+ */
+static inline void
+scif_ordered_memcpy_toio(char *dst, const char *src, size_t count)
+{
+	if (!count)
+		return;
+
+	memcpy_toio((void __iomem __force *)dst, src, --count);
+	/* Order the last byte with the previous stores */
+	wmb();
+	*(dst + count) = *(src + count);
+}
+
+static inline void scif_unaligned_cpy_toio(char *dst, const char *src,
+					   size_t count, bool ordered)
+{
+	if (ordered)
+		scif_ordered_memcpy_toio(dst, src, count);
+	else
+		memcpy_toio((void __iomem __force *)dst, src, count);
+}
+
+static inline
+void scif_ordered_memcpy_fromio(char *dst, const char *src, size_t count)
+{
+	if (!count)
+		return;
+
+	memcpy_fromio(dst, (void __iomem __force *)src, --count);
+	/* Order the last byte with the previous loads */
+	rmb();
+	*(dst + count) = *(src + count);
+}
+
+static inline void scif_unaligned_cpy_fromio(char *dst, const char *src,
+					     size_t count, bool ordered)
+{
+	if (ordered)
+		scif_ordered_memcpy_fromio(dst, src, count);
+	else
+		memcpy_fromio(dst, (void __iomem __force *)src, count);
+}
+
+#define SCIF_RMA_ERROR_CODE (~(dma_addr_t)0x0)
+
+/*
+ * scif_off_to_dma_addr:
+ * Obtain the dma_addr given the window and the offset.
+ * @window: Registered window.
+ * @off: Window offset.
+ * @nr_bytes: Return the number of contiguous bytes till next DMA addr index.
+ * @index: Return the index of the dma_addr array found.
+ * @start_off: start offset of index of the dma addr array found.
+ * The nr_bytes provides the callee an estimate of the maximum possible
+ * DMA xfer possible while the index/start_off provide faster lookups
+ * for the next iteration.
+ */
+dma_addr_t scif_off_to_dma_addr(struct scif_window *window, s64 off,
+				size_t *nr_bytes, struct scif_window_iter *iter)
+{
+	int i, page_nr;
+	s64 start, end;
+	off_t page_off;
+
+	if (window->nr_pages == window->nr_contig_chunks) {
+		page_nr = (off - window->offset) >> PAGE_SHIFT;
+		page_off = off & ~PAGE_MASK;
+
+		if (nr_bytes)
+			*nr_bytes = PAGE_SIZE - page_off;
+		return window->dma_addr[page_nr] | page_off;
+	}
+	if (iter) {
+		i = iter->index;
+		start = iter->offset;
+	} else {
+		i =  0;
+		start =  window->offset;
+	}
+	for (; i < window->nr_contig_chunks; i++) {
+		end = start + (window->num_pages[i] << PAGE_SHIFT);
+		if (off >= start && off < end) {
+			if (iter) {
+				iter->index = i;
+				iter->offset = start;
+			}
+			if (nr_bytes)
+				*nr_bytes = end - off;
+			return (window->dma_addr[i] + (off - start));
+		}
+		start += (window->num_pages[i] << PAGE_SHIFT);
+	}
+	dev_err(scif_info.mdev.this_device,
+		"%s %d BUG. Addr not found? window %p off 0x%llx\n",
+		__func__, __LINE__, window, off);
+	return SCIF_RMA_ERROR_CODE;
+}
+
+/*
+ * Copy between rma window and temporary buffer
+ */
+static void scif_rma_local_cpu_copy(s64 offset, struct scif_window *window,
+				    u8 *temp, size_t rem_len, bool to_temp)
+{
+	void *window_virt;
+	size_t loop_len;
+	int offset_in_page;
+	s64 end_offset;
+
+	offset_in_page = offset & ~PAGE_MASK;
+	loop_len = PAGE_SIZE - offset_in_page;
+
+	if (rem_len < loop_len)
+		loop_len = rem_len;
+
+	window_virt = _get_local_va(offset, window, loop_len);
+	if (!window_virt)
+		return;
+	if (to_temp)
+		memcpy(temp, window_virt, loop_len);
+	else
+		memcpy(window_virt, temp, loop_len);
+
+	offset += loop_len;
+	temp += loop_len;
+	rem_len -= loop_len;
+
+	end_offset = window->offset +
+		(window->nr_pages << PAGE_SHIFT);
+	while (rem_len) {
+		if (offset == end_offset) {
+			window = list_next_entry(window, list);
+			end_offset = window->offset +
+				(window->nr_pages << PAGE_SHIFT);
+		}
+		loop_len = min(PAGE_SIZE, rem_len);
+		window_virt = _get_local_va(offset, window, loop_len);
+		if (!window_virt)
+			return;
+		if (to_temp)
+			memcpy(temp, window_virt, loop_len);
+		else
+			memcpy(window_virt, temp, loop_len);
+		offset	+= loop_len;
+		temp	+= loop_len;
+		rem_len	-= loop_len;
+	}
+}
+
+/**
+ * scif_rma_completion_cb:
+ * @data: RMA cookie
+ *
+ * RMA interrupt completion callback.
+ */
+static void scif_rma_completion_cb(void *data)
+{
+	struct scif_dma_comp_cb *comp_cb = data;
+
+	/* Free DMA Completion CB. */
+	if (comp_cb->dst_window)
+		scif_rma_local_cpu_copy(comp_cb->dst_offset,
+					comp_cb->dst_window,
+					comp_cb->temp_buf +
+					comp_cb->header_padding,
+					comp_cb->len, false);
+	scif_unmap_single(comp_cb->temp_phys, comp_cb->sdev,
+			  SCIF_KMEM_UNALIGNED_BUF_SIZE);
+	if (comp_cb->is_cache)
+		kmem_cache_free(unaligned_cache,
+				comp_cb->temp_buf_to_free);
+	else
+		kfree(comp_cb->temp_buf_to_free);
+}
+
+/* Copies between temporary buffer and offsets provided in work */
+static int
+scif_rma_list_dma_copy_unaligned(struct scif_copy_work *work,
+				 u8 *temp, struct dma_chan *chan,
+				 bool src_local)
+{
+	struct scif_dma_comp_cb *comp_cb = work->comp_cb;
+	dma_addr_t window_dma_addr, temp_dma_addr;
+	dma_addr_t temp_phys = comp_cb->temp_phys;
+	size_t loop_len, nr_contig_bytes = 0, remaining_len = work->len;
+	int offset_in_ca, ret = 0;
+	s64 end_offset, offset;
+	struct scif_window *window;
+	void *window_virt_addr;
+	size_t tail_len;
+	struct dma_async_tx_descriptor *tx;
+	struct dma_device *dev = chan->device;
+	dma_cookie_t cookie;
+
+	if (src_local) {
+		offset = work->dst_offset;
+		window = work->dst_window;
+	} else {
+		offset = work->src_offset;
+		window = work->src_window;
+	}
+
+	offset_in_ca = offset & (L1_CACHE_BYTES - 1);
+	if (offset_in_ca) {
+		loop_len = L1_CACHE_BYTES - offset_in_ca;
+		loop_len = min(loop_len, remaining_len);
+		window_virt_addr = ioremap_remote(offset, window,
+						  loop_len,
+						  work->remote_dev,
+						  NULL);
+		if (!window_virt_addr)
+			return -ENOMEM;
+		if (src_local)
+			scif_unaligned_cpy_toio(window_virt_addr, temp,
+						loop_len,
+						work->ordered &&
+						!(remaining_len - loop_len));
+		else
+			scif_unaligned_cpy_fromio(temp, window_virt_addr,
+						  loop_len, work->ordered &&
+						  !(remaining_len - loop_len));
+		iounmap_remote(window_virt_addr, loop_len, work);
+
+		offset += loop_len;
+		temp += loop_len;
+		temp_phys += loop_len;
+		remaining_len -= loop_len;
+	}
+
+	offset_in_ca = offset & ~PAGE_MASK;
+	end_offset = window->offset +
+		(window->nr_pages << PAGE_SHIFT);
+
+	tail_len = remaining_len & (L1_CACHE_BYTES - 1);
+	remaining_len -= tail_len;
+	while (remaining_len) {
+		if (offset == end_offset) {
+			window = list_next_entry(window, list);
+			end_offset = window->offset +
+				(window->nr_pages << PAGE_SHIFT);
+		}
+		if (scif_is_mgmt_node())
+			temp_dma_addr = temp_phys;
+		else
+			/* Fix if we ever enable IOMMU on the card */
+			temp_dma_addr = (dma_addr_t)virt_to_phys(temp);
+		window_dma_addr = scif_off_to_dma_addr(window, offset,
+						       &nr_contig_bytes,
+						       NULL);
+		loop_len = min(nr_contig_bytes, remaining_len);
+		if (src_local) {
+			if (work->ordered && !tail_len &&
+			    !(remaining_len - loop_len) &&
+			    loop_len != L1_CACHE_BYTES) {
+				/*
+				 * Break up the last chunk of the transfer into
+				 * two steps. if there is no tail to guarantee
+				 * DMA ordering. SCIF_DMA_POLLING inserts
+				 * a status update descriptor in step 1 which
+				 * acts as a double sided synchronization fence
+				 * for the DMA engine to ensure that the last
+				 * cache line in step 2 is updated last.
+				 */
+				/* Step 1) DMA: Body Length - L1_CACHE_BYTES. */
+				tx =
+				dev->device_prep_dma_memcpy(chan,
+							    window_dma_addr,
+							    temp_dma_addr,
+							    loop_len -
+							    L1_CACHE_BYTES,
+							    DMA_PREP_FENCE);
+				if (!tx) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				cookie = tx->tx_submit(tx);
+				if (dma_submit_error(cookie)) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				dma_async_issue_pending(chan);
+				offset += (loop_len - L1_CACHE_BYTES);
+				temp_dma_addr += (loop_len - L1_CACHE_BYTES);
+				window_dma_addr += (loop_len - L1_CACHE_BYTES);
+				remaining_len -= (loop_len - L1_CACHE_BYTES);
+				loop_len = remaining_len;
+
+				/* Step 2) DMA: L1_CACHE_BYTES */
+				tx =
+				dev->device_prep_dma_memcpy(chan,
+							    window_dma_addr,
+							    temp_dma_addr,
+							    loop_len, 0);
+				if (!tx) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				cookie = tx->tx_submit(tx);
+				if (dma_submit_error(cookie)) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				dma_async_issue_pending(chan);
+			} else {
+				tx =
+				dev->device_prep_dma_memcpy(chan,
+							    window_dma_addr,
+							    temp_dma_addr,
+							    loop_len, 0);
+				if (!tx) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				cookie = tx->tx_submit(tx);
+				if (dma_submit_error(cookie)) {
+					ret = -ENOMEM;
+					goto err;
+				}
+				dma_async_issue_pending(chan);
+			}
+		} else {
+			tx = dev->device_prep_dma_memcpy(chan, temp_dma_addr,
+					window_dma_addr, loop_len, 0);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			dma_async_issue_pending(chan);
+		}
+		if (ret < 0)
+			goto err;
+		offset += loop_len;
+		temp += loop_len;
+		temp_phys += loop_len;
+		remaining_len -= loop_len;
+		offset_in_ca = 0;
+	}
+	if (tail_len) {
+		if (offset == end_offset) {
+			window = list_next_entry(window, list);
+			end_offset = window->offset +
+				(window->nr_pages << PAGE_SHIFT);
+		}
+		window_virt_addr = ioremap_remote(offset, window, tail_len,
+						  work->remote_dev,
+						  NULL);
+		if (!window_virt_addr)
+			return -ENOMEM;
+		/*
+		 * The CPU copy for the tail bytes must be initiated only once
+		 * previous DMA transfers for this endpoint have completed
+		 * to guarantee ordering.
+		 */
+		if (work->ordered) {
+			struct scif_dev *rdev = work->remote_dev;
+
+			ret = scif_drain_dma_intr(rdev->sdev, chan);
+			if (ret)
+				return ret;
+		}
+		if (src_local)
+			scif_unaligned_cpy_toio(window_virt_addr, temp,
+						tail_len, work->ordered);
+		else
+			scif_unaligned_cpy_fromio(temp, window_virt_addr,
+						  tail_len, work->ordered);
+		iounmap_remote(window_virt_addr, tail_len, work);
+	}
+	tx = dev->device_prep_dma_memcpy(chan, 0, 0, 0, DMA_PREP_INTERRUPT);
+	if (!tx) {
+		ret = -ENOMEM;
+		return ret;
+	}
+	tx->callback = &scif_rma_completion_cb;
+	tx->callback_param = comp_cb;
+	cookie = tx->tx_submit(tx);
+
+	if (dma_submit_error(cookie)) {
+		ret = -ENOMEM;
+		return ret;
+	}
+	dma_async_issue_pending(chan);
+	return 0;
+err:
+	dev_err(scif_info.mdev.this_device,
+		"%s %d Desc Prog Failed ret %d\n",
+		__func__, __LINE__, ret);
+	return ret;
+}
+
+/*
+ * _scif_rma_list_dma_copy_aligned:
+ *
+ * Traverse all the windows and perform DMA copy.
+ */
+static int _scif_rma_list_dma_copy_aligned(struct scif_copy_work *work,
+					   struct dma_chan *chan)
+{
+	dma_addr_t src_dma_addr, dst_dma_addr;
+	size_t loop_len, remaining_len, src_contig_bytes = 0;
+	size_t dst_contig_bytes = 0;
+	struct scif_window_iter src_win_iter;
+	struct scif_window_iter dst_win_iter;
+	s64 end_src_offset, end_dst_offset;
+	struct scif_window *src_window = work->src_window;
+	struct scif_window *dst_window = work->dst_window;
+	s64 src_offset = work->src_offset, dst_offset = work->dst_offset;
+	int ret = 0;
+	struct dma_async_tx_descriptor *tx;
+	struct dma_device *dev = chan->device;
+	dma_cookie_t cookie;
+
+	remaining_len = work->len;
+
+	scif_init_window_iter(src_window, &src_win_iter);
+	scif_init_window_iter(dst_window, &dst_win_iter);
+	end_src_offset = src_window->offset +
+		(src_window->nr_pages << PAGE_SHIFT);
+	end_dst_offset = dst_window->offset +
+		(dst_window->nr_pages << PAGE_SHIFT);
+	while (remaining_len) {
+		if (src_offset == end_src_offset) {
+			src_window = list_next_entry(src_window, list);
+			end_src_offset = src_window->offset +
+				(src_window->nr_pages << PAGE_SHIFT);
+			scif_init_window_iter(src_window, &src_win_iter);
+		}
+		if (dst_offset == end_dst_offset) {
+			dst_window = list_next_entry(dst_window, list);
+			end_dst_offset = dst_window->offset +
+				(dst_window->nr_pages << PAGE_SHIFT);
+			scif_init_window_iter(dst_window, &dst_win_iter);
+		}
+
+		/* compute dma addresses for transfer */
+		src_dma_addr = scif_off_to_dma_addr(src_window, src_offset,
+						    &src_contig_bytes,
+						    &src_win_iter);
+		dst_dma_addr = scif_off_to_dma_addr(dst_window, dst_offset,
+						    &dst_contig_bytes,
+						    &dst_win_iter);
+		loop_len = min(src_contig_bytes, dst_contig_bytes);
+		loop_len = min(loop_len, remaining_len);
+		if (work->ordered && !(remaining_len - loop_len)) {
+			/*
+			 * Break up the last chunk of the transfer into two
+			 * steps to ensure that the last byte in step 2 is
+			 * updated last.
+			 */
+			/* Step 1) DMA: Body Length - 1 */
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+							 src_dma_addr,
+							 loop_len - 1,
+							 DMA_PREP_FENCE);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			src_offset += (loop_len - 1);
+			dst_offset += (loop_len - 1);
+			src_dma_addr += (loop_len - 1);
+			dst_dma_addr += (loop_len - 1);
+			remaining_len -= (loop_len - 1);
+			loop_len = remaining_len;
+
+			/* Step 2) DMA: 1 BYTES */
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+					src_dma_addr, loop_len, 0);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			dma_async_issue_pending(chan);
+		} else {
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+					src_dma_addr, loop_len, 0);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+		}
+		src_offset += loop_len;
+		dst_offset += loop_len;
+		remaining_len -= loop_len;
+	}
+	return ret;
+err:
+	dev_err(scif_info.mdev.this_device,
+		"%s %d Desc Prog Failed ret %d\n",
+		__func__, __LINE__, ret);
+	return ret;
+}
+
+/*
+ * scif_rma_list_dma_copy_aligned:
+ *
+ * Traverse all the windows and perform DMA copy.
+ */
+static int scif_rma_list_dma_copy_aligned(struct scif_copy_work *work,
+					  struct dma_chan *chan)
+{
+	dma_addr_t src_dma_addr, dst_dma_addr;
+	size_t loop_len, remaining_len, tail_len, src_contig_bytes = 0;
+	size_t dst_contig_bytes = 0;
+	int src_cache_off;
+	s64 end_src_offset, end_dst_offset;
+	struct scif_window_iter src_win_iter;
+	struct scif_window_iter dst_win_iter;
+	void *src_virt, *dst_virt;
+	struct scif_window *src_window = work->src_window;
+	struct scif_window *dst_window = work->dst_window;
+	s64 src_offset = work->src_offset, dst_offset = work->dst_offset;
+	int ret = 0;
+	struct dma_async_tx_descriptor *tx;
+	struct dma_device *dev = chan->device;
+	dma_cookie_t cookie;
+
+	remaining_len = work->len;
+	scif_init_window_iter(src_window, &src_win_iter);
+	scif_init_window_iter(dst_window, &dst_win_iter);
+
+	src_cache_off = src_offset & (L1_CACHE_BYTES - 1);
+	if (src_cache_off != 0) {
+		/* Head */
+		loop_len = L1_CACHE_BYTES - src_cache_off;
+		loop_len = min(loop_len, remaining_len);
+		src_dma_addr = __scif_off_to_dma_addr(src_window, src_offset);
+		dst_dma_addr = __scif_off_to_dma_addr(dst_window, dst_offset);
+		if (src_window->type == SCIF_WINDOW_SELF)
+			src_virt = _get_local_va(src_offset, src_window,
+						 loop_len);
+		else
+			src_virt = ioremap_remote(src_offset, src_window,
+						  loop_len,
+						  work->remote_dev, NULL);
+		if (!src_virt)
+			return -ENOMEM;
+		if (dst_window->type == SCIF_WINDOW_SELF)
+			dst_virt = _get_local_va(dst_offset, dst_window,
+						 loop_len);
+		else
+			dst_virt = ioremap_remote(dst_offset, dst_window,
+						  loop_len,
+						  work->remote_dev, NULL);
+		if (!dst_virt) {
+			if (src_window->type != SCIF_WINDOW_SELF)
+				iounmap_remote(src_virt, loop_len, work);
+			return -ENOMEM;
+		}
+		if (src_window->type == SCIF_WINDOW_SELF)
+			scif_unaligned_cpy_toio(dst_virt, src_virt, loop_len,
+						remaining_len == loop_len ?
+						work->ordered : false);
+		else
+			scif_unaligned_cpy_fromio(dst_virt, src_virt, loop_len,
+						  remaining_len == loop_len ?
+						  work->ordered : false);
+		if (src_window->type != SCIF_WINDOW_SELF)
+			iounmap_remote(src_virt, loop_len, work);
+		if (dst_window->type != SCIF_WINDOW_SELF)
+			iounmap_remote(dst_virt, loop_len, work);
+		src_offset += loop_len;
+		dst_offset += loop_len;
+		remaining_len -= loop_len;
+	}
+
+	end_src_offset = src_window->offset +
+		(src_window->nr_pages << PAGE_SHIFT);
+	end_dst_offset = dst_window->offset +
+		(dst_window->nr_pages << PAGE_SHIFT);
+	tail_len = remaining_len & (L1_CACHE_BYTES - 1);
+	remaining_len -= tail_len;
+	while (remaining_len) {
+		if (src_offset == end_src_offset) {
+			src_window = list_next_entry(src_window, list);
+			end_src_offset = src_window->offset +
+				(src_window->nr_pages << PAGE_SHIFT);
+			scif_init_window_iter(src_window, &src_win_iter);
+		}
+		if (dst_offset == end_dst_offset) {
+			dst_window = list_next_entry(dst_window, list);
+			end_dst_offset = dst_window->offset +
+				(dst_window->nr_pages << PAGE_SHIFT);
+			scif_init_window_iter(dst_window, &dst_win_iter);
+		}
+
+		/* compute dma addresses for transfer */
+		src_dma_addr = scif_off_to_dma_addr(src_window, src_offset,
+						    &src_contig_bytes,
+						    &src_win_iter);
+		dst_dma_addr = scif_off_to_dma_addr(dst_window, dst_offset,
+						    &dst_contig_bytes,
+						    &dst_win_iter);
+		loop_len = min(src_contig_bytes, dst_contig_bytes);
+		loop_len = min(loop_len, remaining_len);
+		if (work->ordered && !tail_len &&
+		    !(remaining_len - loop_len)) {
+			/*
+			 * Break up the last chunk of the transfer into two
+			 * steps. if there is no tail to gurantee DMA ordering.
+			 * Passing SCIF_DMA_POLLING inserts a status update
+			 * descriptor in step 1 which acts as a double sided
+			 * synchronization fence for the DMA engine to ensure
+			 * that the last cache line in step 2 is updated last.
+			 */
+			/* Step 1) DMA: Body Length - L1_CACHE_BYTES. */
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+							 src_dma_addr,
+							 loop_len -
+							 L1_CACHE_BYTES,
+							 DMA_PREP_FENCE);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			dma_async_issue_pending(chan);
+			src_offset += (loop_len - L1_CACHE_BYTES);
+			dst_offset += (loop_len - L1_CACHE_BYTES);
+			src_dma_addr += (loop_len - L1_CACHE_BYTES);
+			dst_dma_addr += (loop_len - L1_CACHE_BYTES);
+			remaining_len -= (loop_len - L1_CACHE_BYTES);
+			loop_len = remaining_len;
+
+			/* Step 2) DMA: L1_CACHE_BYTES */
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+							 src_dma_addr,
+							 loop_len, 0);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			dma_async_issue_pending(chan);
+		} else {
+			tx = dev->device_prep_dma_memcpy(chan, dst_dma_addr,
+							 src_dma_addr,
+							 loop_len, 0);
+			if (!tx) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			cookie = tx->tx_submit(tx);
+			if (dma_submit_error(cookie)) {
+				ret = -ENOMEM;
+				goto err;
+			}
+			dma_async_issue_pending(chan);
+		}
+		src_offset += loop_len;
+		dst_offset += loop_len;
+		remaining_len -= loop_len;
+	}
+	remaining_len = tail_len;
+	if (remaining_len) {
+		loop_len = remaining_len;
+		if (src_offset == end_src_offset)
+			src_window = list_next_entry(src_window, list);
+		if (dst_offset == end_dst_offset)
+			dst_window = list_next_entry(dst_window, list);
+
+		src_dma_addr = __scif_off_to_dma_addr(src_window, src_offset);
+		dst_dma_addr = __scif_off_to_dma_addr(dst_window, dst_offset);
+		/*
+		 * The CPU copy for the tail bytes must be initiated only once
+		 * previous DMA transfers for this endpoint have completed to
+		 * guarantee ordering.
+		 */
+		if (work->ordered) {
+			struct scif_dev *rdev = work->remote_dev;
+
+			ret = scif_drain_dma_poll(rdev->sdev, chan);
+			if (ret)
+				return ret;
+		}
+		if (src_window->type == SCIF_WINDOW_SELF)
+			src_virt = _get_local_va(src_offset, src_window,
+						 loop_len);
+		else
+			src_virt = ioremap_remote(src_offset, src_window,
+						  loop_len,
+						  work->remote_dev, NULL);
+		if (!src_virt)
+			return -ENOMEM;
+
+		if (dst_window->type == SCIF_WINDOW_SELF)
+			dst_virt = _get_local_va(dst_offset, dst_window,
+						 loop_len);
+		else
+			dst_virt = ioremap_remote(dst_offset, dst_window,
+						  loop_len,
+						  work->remote_dev, NULL);
+		if (!dst_virt) {
+			if (src_window->type != SCIF_WINDOW_SELF)
+				iounmap_remote(src_virt, loop_len, work);
+			return -ENOMEM;
+		}
+
+		if (src_window->type == SCIF_WINDOW_SELF)
+			scif_unaligned_cpy_toio(dst_virt, src_virt, loop_len,
+						work->ordered);
+		else
+			scif_unaligned_cpy_fromio(dst_virt, src_virt,
+						  loop_len, work->ordered);
+		if (src_window->type != SCIF_WINDOW_SELF)
+			iounmap_remote(src_virt, loop_len, work);
+
+		if (dst_window->type != SCIF_WINDOW_SELF)
+			iounmap_remote(dst_virt, loop_len, work);
+		remaining_len -= loop_len;
+	}
+	return ret;
+err:
+	dev_err(scif_info.mdev.this_device,
+		"%s %d Desc Prog Failed ret %d\n",
+		__func__, __LINE__, ret);
+	return ret;
+}
+
+/*
+ * scif_rma_list_cpu_copy:
+ *
+ * Traverse all the windows and perform CPU copy.
+ */
+static int scif_rma_list_cpu_copy(struct scif_copy_work *work)
+{
+	void *src_virt, *dst_virt;
+	size_t loop_len, remaining_len;
+	int src_page_off, dst_page_off;
+	s64 src_offset = work->src_offset, dst_offset = work->dst_offset;
+	struct scif_window *src_window = work->src_window;
+	struct scif_window *dst_window = work->dst_window;
+	s64 end_src_offset, end_dst_offset;
+	int ret = 0;
+	struct scif_window_iter src_win_iter;
+	struct scif_window_iter dst_win_iter;
+
+	remaining_len = work->len;
+
+	scif_init_window_iter(src_window, &src_win_iter);
+	scif_init_window_iter(dst_window, &dst_win_iter);
+	while (remaining_len) {
+		src_page_off = src_offset & ~PAGE_MASK;
+		dst_page_off = dst_offset & ~PAGE_MASK;
+		loop_len = min(PAGE_SIZE -
+			       max(src_page_off, dst_page_off),
+			       remaining_len);
+
+		if (src_window->type == SCIF_WINDOW_SELF)
+			src_virt = _get_local_va(src_offset, src_window,
+						 loop_len);
+		else
+			src_virt = ioremap_remote(src_offset, src_window,
+						  loop_len,
+						  work->remote_dev,
+						  &src_win_iter);
+		if (!src_virt) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		if (dst_window->type == SCIF_WINDOW_SELF)
+			dst_virt = _get_local_va(dst_offset, dst_window,
+						 loop_len);
+		else
+			dst_virt = ioremap_remote(dst_offset, dst_window,
+						  loop_len,
+						  work->remote_dev,
+						  &dst_win_iter);
+		if (!dst_virt) {
+			if (src_window->type == SCIF_WINDOW_PEER)
+				iounmap_remote(src_virt, loop_len, work);
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		if (work->loopback) {
+			memcpy(dst_virt, src_virt, loop_len);
+		} else {
+			if (src_window->type == SCIF_WINDOW_SELF)
+				memcpy_toio((void __iomem __force *)dst_virt,
+					    src_virt, loop_len);
+			else
+				memcpy_fromio(dst_virt,
+					      (void __iomem __force *)src_virt,
+					      loop_len);
+		}
+		if (src_window->type == SCIF_WINDOW_PEER)
+			iounmap_remote(src_virt, loop_len, work);
+
+		if (dst_window->type == SCIF_WINDOW_PEER)
+			iounmap_remote(dst_virt, loop_len, work);
+
+		src_offset += loop_len;
+		dst_offset += loop_len;
+		remaining_len -= loop_len;
+		if (remaining_len) {
+			end_src_offset = src_window->offset +
+				(src_window->nr_pages << PAGE_SHIFT);
+			end_dst_offset = dst_window->offset +
+				(dst_window->nr_pages << PAGE_SHIFT);
+			if (src_offset == end_src_offset) {
+				src_window = list_next_entry(src_window, list);
+				scif_init_window_iter(src_window,
+						      &src_win_iter);
+			}
+			if (dst_offset == end_dst_offset) {
+				dst_window = list_next_entry(dst_window, list);
+				scif_init_window_iter(dst_window,
+						      &dst_win_iter);
+			}
+		}
+	}
+error:
+	return ret;
+}
+
+static int scif_rma_list_dma_copy_wrapper(struct scif_endpt *epd,
+					  struct scif_copy_work *work,
+					  struct dma_chan *chan, off_t loffset)
+{
+	int src_cache_off, dst_cache_off;
+	s64 src_offset = work->src_offset, dst_offset = work->dst_offset;
+	u8 *temp = NULL;
+	bool src_local = true, dst_local = false;
+	struct scif_dma_comp_cb *comp_cb;
+	dma_addr_t src_dma_addr, dst_dma_addr;
+	int err;
+
+	if (is_dma_copy_aligned(chan->device, 1, 1, 1))
+		return _scif_rma_list_dma_copy_aligned(work, chan);
+
+	src_cache_off = src_offset & (L1_CACHE_BYTES - 1);
+	dst_cache_off = dst_offset & (L1_CACHE_BYTES - 1);
+
+	if (dst_cache_off == src_cache_off)
+		return scif_rma_list_dma_copy_aligned(work, chan);
+
+	if (work->loopback)
+		return scif_rma_list_cpu_copy(work);
+	src_dma_addr = __scif_off_to_dma_addr(work->src_window, src_offset);
+	dst_dma_addr = __scif_off_to_dma_addr(work->dst_window, dst_offset);
+	src_local = work->src_window->type == SCIF_WINDOW_SELF;
+	dst_local = work->dst_window->type == SCIF_WINDOW_SELF;
+
+	dst_local = dst_local;
+	/* Allocate dma_completion cb */
+	comp_cb = kzalloc(sizeof(*comp_cb), GFP_KERNEL);
+	if (!comp_cb)
+		goto error;
+
+	work->comp_cb = comp_cb;
+	comp_cb->cb_cookie = comp_cb;
+	comp_cb->dma_completion_func = &scif_rma_completion_cb;
+
+	if (work->len + (L1_CACHE_BYTES << 1) < SCIF_KMEM_UNALIGNED_BUF_SIZE) {
+		comp_cb->is_cache = false;
+		/* Allocate padding bytes to align to a cache line */
+		temp = kmalloc(work->len + (L1_CACHE_BYTES << 1),
+			       GFP_KERNEL);
+		if (!temp)
+			goto free_comp_cb;
+		comp_cb->temp_buf_to_free = temp;
+		/* kmalloc(..) does not guarantee cache line alignment */
+		if (!IS_ALIGNED((u64)temp, L1_CACHE_BYTES))
+			temp = PTR_ALIGN(temp, L1_CACHE_BYTES);
+	} else {
+		comp_cb->is_cache = true;
+		temp = kmem_cache_alloc(unaligned_cache, GFP_KERNEL);
+		if (!temp)
+			goto free_comp_cb;
+		comp_cb->temp_buf_to_free = temp;
+	}
+
+	if (src_local) {
+		temp += dst_cache_off;
+		scif_rma_local_cpu_copy(work->src_offset, work->src_window,
+					temp, work->len, true);
+	} else {
+		comp_cb->dst_window = work->dst_window;
+		comp_cb->dst_offset = work->dst_offset;
+		work->src_offset = work->src_offset - src_cache_off;
+		comp_cb->len = work->len;
+		work->len = ALIGN(work->len + src_cache_off, L1_CACHE_BYTES);
+		comp_cb->header_padding = src_cache_off;
+	}
+	comp_cb->temp_buf = temp;
+
+	err = scif_map_single(&comp_cb->temp_phys, temp,
+			      work->remote_dev, SCIF_KMEM_UNALIGNED_BUF_SIZE);
+	if (err)
+		goto free_temp_buf;
+	comp_cb->sdev = work->remote_dev;
+	if (scif_rma_list_dma_copy_unaligned(work, temp, chan, src_local) < 0)
+		goto free_temp_buf;
+	if (!src_local)
+		work->fence_type = SCIF_DMA_INTR;
+	return 0;
+free_temp_buf:
+	if (comp_cb->is_cache)
+		kmem_cache_free(unaligned_cache, comp_cb->temp_buf_to_free);
+	else
+		kfree(comp_cb->temp_buf_to_free);
+free_comp_cb:
+	kfree(comp_cb);
+error:
+	return -ENOMEM;
+}
+
+/**
+ * scif_rma_copy:
+ * @epd: end point descriptor.
+ * @loffset: offset in local registered address space to/from which to copy
+ * @addr: user virtual address to/from which to copy
+ * @len: length of range to copy
+ * @roffset: offset in remote registered address space to/from which to copy
+ * @flags: flags
+ * @dir: LOCAL->REMOTE or vice versa.
+ * @last_chunk: true if this is the last chunk of a larger transfer
+ *
+ * Validate parameters, check if src/dst registered ranges requested for copy
+ * are valid and initiate either CPU or DMA copy.
+ */
+static int scif_rma_copy(scif_epd_t epd, off_t loffset, unsigned long addr,
+			 size_t len, off_t roffset, int flags,
+			 enum scif_rma_dir dir, bool last_chunk)
+{
+	struct scif_endpt *ep = (struct scif_endpt *)epd;
+	struct scif_rma_req remote_req;
+	struct scif_rma_req req;
+	struct scif_window *local_window = NULL;
+	struct scif_window *remote_window = NULL;
+	struct scif_copy_work copy_work;
+	bool loopback;
+	int err = 0;
+	struct dma_chan *chan;
+	struct scif_mmu_notif *mmn = NULL;
+	bool cache = false;
+	struct device *spdev;
+
+	err = scif_verify_epd(ep);
+	if (err)
+		return err;
+
+	if (flags && !(flags & (SCIF_RMA_USECPU | SCIF_RMA_USECACHE |
+				SCIF_RMA_SYNC | SCIF_RMA_ORDERED)))
+		return -EINVAL;
+
+	loopback = scifdev_self(ep->remote_dev) ? true : false;
+	copy_work.fence_type = ((flags & SCIF_RMA_SYNC) && last_chunk) ?
+				SCIF_DMA_POLL : 0;
+	copy_work.ordered = !!((flags & SCIF_RMA_ORDERED) && last_chunk);
+
+	/* Use CPU for Mgmt node <-> Mgmt node copies */
+	if (loopback && scif_is_mgmt_node()) {
+		flags |= SCIF_RMA_USECPU;
+		copy_work.fence_type = 0x0;
+	}
+
+	cache = scif_is_set_reg_cache(flags);
+
+	remote_req.out_window = &remote_window;
+	remote_req.offset = roffset;
+	remote_req.nr_bytes = len;
+	/*
+	 * If transfer is from local to remote then the remote window
+	 * must be writeable and vice versa.
+	 */
+	remote_req.prot = dir == SCIF_LOCAL_TO_REMOTE ? VM_WRITE : VM_READ;
+	remote_req.type = SCIF_WINDOW_PARTIAL;
+	remote_req.head = &ep->rma_info.remote_reg_list;
+
+	spdev = scif_get_peer_dev(ep->remote_dev);
+	if (IS_ERR(spdev)) {
+		err = PTR_ERR(spdev);
+		return err;
+	}
+
+	if (addr && cache) {
+		mutex_lock(&ep->rma_info.mmn_lock);
+		mmn = scif_find_mmu_notifier(current->mm, &ep->rma_info);
+		if (!mmn)
+			mmn = scif_add_mmu_notifier(current->mm, ep);
+		mutex_unlock(&ep->rma_info.mmn_lock);
+		if (IS_ERR(mmn)) {
+			scif_put_peer_dev(spdev);
+			return PTR_ERR(mmn);
+		}
+		cache = cache && !scif_rma_tc_can_cache(ep, len);
+	}
+	mutex_lock(&ep->rma_info.rma_lock);
+	if (addr) {
+		req.out_window = &local_window;
+		req.nr_bytes = ALIGN(len + (addr & ~PAGE_MASK),
+				     PAGE_SIZE);
+		req.va_for_temp = addr & PAGE_MASK;
+		req.prot = (dir == SCIF_LOCAL_TO_REMOTE ?
+			    VM_READ : VM_WRITE | VM_READ);
+		/* Does a valid local window exist? */
+		if (mmn) {
+			spin_lock(&ep->rma_info.tc_lock);
+			req.head = &mmn->tc_reg_list;
+			err = scif_query_tcw(ep, &req);
+			spin_unlock(&ep->rma_info.tc_lock);
+		}
+		if (!mmn || err) {
+			err = scif_register_temp(epd, req.va_for_temp,
+						 req.nr_bytes, req.prot,
+						 &loffset, &local_window);
+			if (err) {
+				mutex_unlock(&ep->rma_info.rma_lock);
+				goto error;
+			}
+			if (!cache)
+				goto skip_cache;
+			atomic_inc(&ep->rma_info.tcw_refcount);
+			atomic_add_return(local_window->nr_pages,
+					  &ep->rma_info.tcw_total_pages);
+			if (mmn) {
+				spin_lock(&ep->rma_info.tc_lock);
+				scif_insert_tcw(local_window,
+						&mmn->tc_reg_list);
+				spin_unlock(&ep->rma_info.tc_lock);
+			}
+		}
+skip_cache:
+		loffset = local_window->offset +
+				(addr - local_window->va_for_temp);
+	} else {
+		req.out_window = &local_window;
+		req.offset = loffset;
+		/*
+		 * If transfer is from local to remote then the self window
+		 * must be readable and vice versa.
+		 */
+		req.prot = dir == SCIF_LOCAL_TO_REMOTE ? VM_READ : VM_WRITE;
+		req.nr_bytes = len;
+		req.type = SCIF_WINDOW_PARTIAL;
+		req.head = &ep->rma_info.reg_list;
+		/* Does a valid local window exist? */
+		err = scif_query_window(&req);
+		if (err) {
+			mutex_unlock(&ep->rma_info.rma_lock);
+			goto error;
+		}
+	}
+
+	/* Does a valid remote window exist? */
+	err = scif_query_window(&remote_req);
+	if (err) {
+		mutex_unlock(&ep->rma_info.rma_lock);
+		goto error;
+	}
+
+	/*
+	 * Prepare copy_work for submitting work to the DMA kernel thread
+	 * or CPU copy routine.
+	 */
+	copy_work.len = len;
+	copy_work.loopback = loopback;
+	copy_work.remote_dev = ep->remote_dev;
+	if (dir == SCIF_LOCAL_TO_REMOTE) {
+		copy_work.src_offset = loffset;
+		copy_work.src_window = local_window;
+		copy_work.dst_offset = roffset;
+		copy_work.dst_window = remote_window;
+	} else {
+		copy_work.src_offset = roffset;
+		copy_work.src_window = remote_window;
+		copy_work.dst_offset = loffset;
+		copy_work.dst_window = local_window;
+	}
+
+	if (flags & SCIF_RMA_USECPU) {
+		scif_rma_list_cpu_copy(&copy_work);
+	} else {
+		chan = ep->rma_info.dma_chan;
+		err = scif_rma_list_dma_copy_wrapper(epd, &copy_work,
+						     chan, loffset);
+	}
+	if (addr && !cache)
+		atomic_inc(&ep->rma_info.tw_refcount);
+
+	mutex_unlock(&ep->rma_info.rma_lock);
+
+	if (last_chunk) {
+		struct scif_dev *rdev = ep->remote_dev;
+
+		if (copy_work.fence_type == SCIF_DMA_POLL)
+			err = scif_drain_dma_poll(rdev->sdev,
+						  ep->rma_info.dma_chan);
+		else if (copy_work.fence_type == SCIF_DMA_INTR)
+			err = scif_drain_dma_intr(rdev->sdev,
+						  ep->rma_info.dma_chan);
+	}
+
+	if (addr && !cache)
+		scif_queue_for_cleanup(local_window, &scif_info.rma);
+	scif_put_peer_dev(spdev);
+	return err;
+error:
+	if (err) {
+		if (addr && local_window && !cache)
+			scif_destroy_window(ep, local_window);
+		dev_err(scif_info.mdev.this_device,
+			"%s %d err %d len 0x%lx\n",
+			__func__, __LINE__, err, len);
+	}
+	scif_put_peer_dev(spdev);
+	return err;
+}
+
+int scif_readfrom(scif_epd_t epd, off_t loffset, size_t len,
+		  off_t roffset, int flags)
+{
+	int err;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI readfrom: ep %p loffset 0x%lx len 0x%lx offset 0x%lx flags 0x%x\n",
+		epd, loffset, len, roffset, flags);
+	if (scif_unaligned(loffset, roffset)) {
+		while (len > SCIF_MAX_UNALIGNED_BUF_SIZE) {
+			err = scif_rma_copy(epd, loffset, 0x0,
+					    SCIF_MAX_UNALIGNED_BUF_SIZE,
+					    roffset, flags,
+					    SCIF_REMOTE_TO_LOCAL, false);
+			if (err)
+				goto readfrom_err;
+			loffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			roffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			len -= SCIF_MAX_UNALIGNED_BUF_SIZE;
+		}
+	}
+	err = scif_rma_copy(epd, loffset, 0x0, len,
+			    roffset, flags, SCIF_REMOTE_TO_LOCAL, true);
+readfrom_err:
+	return err;
+}
+EXPORT_SYMBOL_GPL(scif_readfrom);
+
+int scif_writeto(scif_epd_t epd, off_t loffset, size_t len,
+		 off_t roffset, int flags)
+{
+	int err;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI writeto: ep %p loffset 0x%lx len 0x%lx roffset 0x%lx flags 0x%x\n",
+		epd, loffset, len, roffset, flags);
+	if (scif_unaligned(loffset, roffset)) {
+		while (len > SCIF_MAX_UNALIGNED_BUF_SIZE) {
+			err = scif_rma_copy(epd, loffset, 0x0,
+					    SCIF_MAX_UNALIGNED_BUF_SIZE,
+					    roffset, flags,
+					    SCIF_LOCAL_TO_REMOTE, false);
+			if (err)
+				goto writeto_err;
+			loffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			roffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			len -= SCIF_MAX_UNALIGNED_BUF_SIZE;
+		}
+	}
+	err = scif_rma_copy(epd, loffset, 0x0, len,
+			    roffset, flags, SCIF_LOCAL_TO_REMOTE, true);
+writeto_err:
+	return err;
+}
+EXPORT_SYMBOL_GPL(scif_writeto);
+
+int scif_vreadfrom(scif_epd_t epd, void *addr, size_t len,
+		   off_t roffset, int flags)
+{
+	int err;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI vreadfrom: ep %p addr %p len 0x%lx roffset 0x%lx flags 0x%x\n",
+		epd, addr, len, roffset, flags);
+	if (scif_unaligned((off_t __force)addr, roffset)) {
+		if (len > SCIF_MAX_UNALIGNED_BUF_SIZE)
+			flags &= ~SCIF_RMA_USECACHE;
+
+		while (len > SCIF_MAX_UNALIGNED_BUF_SIZE) {
+			err = scif_rma_copy(epd, 0, (u64)addr,
+					    SCIF_MAX_UNALIGNED_BUF_SIZE,
+					    roffset, flags,
+					    SCIF_REMOTE_TO_LOCAL, false);
+			if (err)
+				goto vreadfrom_err;
+			addr += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			roffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			len -= SCIF_MAX_UNALIGNED_BUF_SIZE;
+		}
+	}
+	err = scif_rma_copy(epd, 0, (u64)addr, len,
+			    roffset, flags, SCIF_REMOTE_TO_LOCAL, true);
+vreadfrom_err:
+	return err;
+}
+EXPORT_SYMBOL_GPL(scif_vreadfrom);
+
+int scif_vwriteto(scif_epd_t epd, void *addr, size_t len,
+		  off_t roffset, int flags)
+{
+	int err;
+
+	dev_dbg(scif_info.mdev.this_device,
+		"SCIFAPI vwriteto: ep %p addr %p len 0x%lx roffset 0x%lx flags 0x%x\n",
+		epd, addr, len, roffset, flags);
+	if (scif_unaligned((off_t __force)addr, roffset)) {
+		if (len > SCIF_MAX_UNALIGNED_BUF_SIZE)
+			flags &= ~SCIF_RMA_USECACHE;
+
+		while (len > SCIF_MAX_UNALIGNED_BUF_SIZE) {
+			err = scif_rma_copy(epd, 0, (u64)addr,
+					    SCIF_MAX_UNALIGNED_BUF_SIZE,
+					    roffset, flags,
+					    SCIF_LOCAL_TO_REMOTE, false);
+			if (err)
+				goto vwriteto_err;
+			addr += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			roffset += SCIF_MAX_UNALIGNED_BUF_SIZE;
+			len -= SCIF_MAX_UNALIGNED_BUF_SIZE;
+		}
+	}
+	err = scif_rma_copy(epd, 0, (u64)addr, len,
+			    roffset, flags, SCIF_LOCAL_TO_REMOTE, true);
+vwriteto_err:
+	return err;
+}
+EXPORT_SYMBOL_GPL(scif_vwriteto);