Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 791 insertions, 0 deletions

diff --git a/drivers/crypto/ccp/ccp-dmaengine.c b/drivers/crypto/ccp/ccp-dmaengine.c
new file mode 100644
index 000000000..b386a7063
--- /dev/null
+++ b/drivers/crypto/ccp/ccp-dmaengine.c
@@ -0,0 +1,791 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AMD Cryptographic Coprocessor (CCP) driver
+ *
+ * Copyright (C) 2016,2019 Advanced Micro Devices, Inc.
+ *
+ * Author: Gary R Hook <gary.hook@amd.com>
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmaengine.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/ccp.h>
+
+#include "ccp-dev.h"
+#include "../../dma/dmaengine.h"
+
+#define CCP_DMA_WIDTH(_mask)		\
+({					\
+	u64 mask = _mask + 1;		\
+	(mask == 0) ? 64 : fls64(mask);	\
+})
+
+/* The CCP as a DMA provider can be configured for public or private
+ * channels. Default is specified in the vdata for the device (PCI ID).
+ * This module parameter will override for all channels on all devices:
+ *   dma_chan_attr = 0x2 to force all channels public
+ *                 = 0x1 to force all channels private
+ *                 = 0x0 to defer to the vdata setting
+ *                 = any other value: warning, revert to 0x0
+ */
+static unsigned int dma_chan_attr = CCP_DMA_DFLT;
+module_param(dma_chan_attr, uint, 0444);
+MODULE_PARM_DESC(dma_chan_attr, "Set DMA channel visibility: 0 (default) = device defaults, 1 = make private, 2 = make public");
+
+static unsigned int dmaengine = 1;
+module_param(dmaengine, uint, 0444);
+MODULE_PARM_DESC(dmaengine, "Register services with the DMA subsystem (any non-zero value, default: 1)");
+
+static unsigned int ccp_get_dma_chan_attr(struct ccp_device *ccp)
+{
+	switch (dma_chan_attr) {
+	case CCP_DMA_DFLT:
+		return ccp->vdata->dma_chan_attr;
+
+	case CCP_DMA_PRIV:
+		return DMA_PRIVATE;
+
+	case CCP_DMA_PUB:
+		return 0;
+
+	default:
+		dev_info_once(ccp->dev, "Invalid value for dma_chan_attr: %d\n",
+			      dma_chan_attr);
+		return ccp->vdata->dma_chan_attr;
+	}
+}
+
+static void ccp_free_cmd_resources(struct ccp_device *ccp,
+				   struct list_head *list)
+{
+	struct ccp_dma_cmd *cmd, *ctmp;
+
+	list_for_each_entry_safe(cmd, ctmp, list, entry) {
+		list_del(&cmd->entry);
+		kmem_cache_free(ccp->dma_cmd_cache, cmd);
+	}
+}
+
+static void ccp_free_desc_resources(struct ccp_device *ccp,
+				    struct list_head *list)
+{
+	struct ccp_dma_desc *desc, *dtmp;
+
+	list_for_each_entry_safe(desc, dtmp, list, entry) {
+		ccp_free_cmd_resources(ccp, &desc->active);
+		ccp_free_cmd_resources(ccp, &desc->pending);
+
+		list_del(&desc->entry);
+		kmem_cache_free(ccp->dma_desc_cache, desc);
+	}
+}
+
+static void ccp_free_chan_resources(struct dma_chan *dma_chan)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	unsigned long flags;
+
+	dev_dbg(chan->ccp->dev, "%s - chan=%p\n", __func__, chan);
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	ccp_free_desc_resources(chan->ccp, &chan->complete);
+	ccp_free_desc_resources(chan->ccp, &chan->active);
+	ccp_free_desc_resources(chan->ccp, &chan->pending);
+	ccp_free_desc_resources(chan->ccp, &chan->created);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static void ccp_cleanup_desc_resources(struct ccp_device *ccp,
+				       struct list_head *list)
+{
+	struct ccp_dma_desc *desc, *dtmp;
+
+	list_for_each_entry_safe_reverse(desc, dtmp, list, entry) {
+		if (!async_tx_test_ack(&desc->tx_desc))
+			continue;
+
+		dev_dbg(ccp->dev, "%s - desc=%p\n", __func__, desc);
+
+		ccp_free_cmd_resources(ccp, &desc->active);
+		ccp_free_cmd_resources(ccp, &desc->pending);
+
+		list_del(&desc->entry);
+		kmem_cache_free(ccp->dma_desc_cache, desc);
+	}
+}
+
+static void ccp_do_cleanup(unsigned long data)
+{
+	struct ccp_dma_chan *chan = (struct ccp_dma_chan *)data;
+	unsigned long flags;
+
+	dev_dbg(chan->ccp->dev, "%s - chan=%s\n", __func__,
+		dma_chan_name(&chan->dma_chan));
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	ccp_cleanup_desc_resources(chan->ccp, &chan->complete);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+
+static int ccp_issue_next_cmd(struct ccp_dma_desc *desc)
+{
+	struct ccp_dma_cmd *cmd;
+	int ret;
+
+	cmd = list_first_entry(&desc->pending, struct ccp_dma_cmd, entry);
+	list_move(&cmd->entry, &desc->active);
+
+	dev_dbg(desc->ccp->dev, "%s - tx %d, cmd=%p\n", __func__,
+		desc->tx_desc.cookie, cmd);
+
+	ret = ccp_enqueue_cmd(&cmd->ccp_cmd);
+	if (!ret || (ret == -EINPROGRESS) || (ret == -EBUSY))
+		return 0;
+
+	dev_dbg(desc->ccp->dev, "%s - error: ret=%d, tx %d, cmd=%p\n", __func__,
+		ret, desc->tx_desc.cookie, cmd);
+
+	return ret;
+}
+
+static void ccp_free_active_cmd(struct ccp_dma_desc *desc)
+{
+	struct ccp_dma_cmd *cmd;
+
+	cmd = list_first_entry_or_null(&desc->active, struct ccp_dma_cmd,
+				       entry);
+	if (!cmd)
+		return;
+
+	dev_dbg(desc->ccp->dev, "%s - freeing tx %d cmd=%p\n",
+		__func__, desc->tx_desc.cookie, cmd);
+
+	list_del(&cmd->entry);
+	kmem_cache_free(desc->ccp->dma_cmd_cache, cmd);
+}
+
+static struct ccp_dma_desc *__ccp_next_dma_desc(struct ccp_dma_chan *chan,
+						struct ccp_dma_desc *desc)
+{
+	/* Move current DMA descriptor to the complete list */
+	if (desc)
+		list_move(&desc->entry, &chan->complete);
+
+	/* Get the next DMA descriptor on the active list */
+	desc = list_first_entry_or_null(&chan->active, struct ccp_dma_desc,
+					entry);
+
+	return desc;
+}
+
+static struct ccp_dma_desc *ccp_handle_active_desc(struct ccp_dma_chan *chan,
+						   struct ccp_dma_desc *desc)
+{
+	struct dma_async_tx_descriptor *tx_desc;
+	unsigned long flags;
+
+	/* Loop over descriptors until one is found with commands */
+	do {
+		if (desc) {
+			/* Remove the DMA command from the list and free it */
+			ccp_free_active_cmd(desc);
+
+			if (!list_empty(&desc->pending)) {
+				/* No errors, keep going */
+				if (desc->status != DMA_ERROR)
+					return desc;
+
+				/* Error, free remaining commands and move on */
+				ccp_free_cmd_resources(desc->ccp,
+						       &desc->pending);
+			}
+
+			tx_desc = &desc->tx_desc;
+		} else {
+			tx_desc = NULL;
+		}
+
+		spin_lock_irqsave(&chan->lock, flags);
+
+		if (desc) {
+			if (desc->status != DMA_ERROR)
+				desc->status = DMA_COMPLETE;
+
+			dev_dbg(desc->ccp->dev,
+				"%s - tx %d complete, status=%u\n", __func__,
+				desc->tx_desc.cookie, desc->status);
+
+			dma_cookie_complete(tx_desc);
+			dma_descriptor_unmap(tx_desc);
+		}
+
+		desc = __ccp_next_dma_desc(chan, desc);
+
+		spin_unlock_irqrestore(&chan->lock, flags);
+
+		if (tx_desc) {
+			dmaengine_desc_get_callback_invoke(tx_desc, NULL);
+
+			dma_run_dependencies(tx_desc);
+		}
+	} while (desc);
+
+	return NULL;
+}
+
+static struct ccp_dma_desc *__ccp_pending_to_active(struct ccp_dma_chan *chan)
+{
+	struct ccp_dma_desc *desc;
+
+	if (list_empty(&chan->pending))
+		return NULL;
+
+	desc = list_empty(&chan->active)
+		? list_first_entry(&chan->pending, struct ccp_dma_desc, entry)
+		: NULL;
+
+	list_splice_tail_init(&chan->pending, &chan->active);
+
+	return desc;
+}
+
+static void ccp_cmd_callback(void *data, int err)
+{
+	struct ccp_dma_desc *desc = data;
+	struct ccp_dma_chan *chan;
+	int ret;
+
+	if (err == -EINPROGRESS)
+		return;
+
+	chan = container_of(desc->tx_desc.chan, struct ccp_dma_chan,
+			    dma_chan);
+
+	dev_dbg(chan->ccp->dev, "%s - tx %d callback, err=%d\n",
+		__func__, desc->tx_desc.cookie, err);
+
+	if (err)
+		desc->status = DMA_ERROR;
+
+	while (true) {
+		/* Check for DMA descriptor completion */
+		desc = ccp_handle_active_desc(chan, desc);
+
+		/* Don't submit cmd if no descriptor or DMA is paused */
+		if (!desc || (chan->status == DMA_PAUSED))
+			break;
+
+		ret = ccp_issue_next_cmd(desc);
+		if (!ret)
+			break;
+
+		desc->status = DMA_ERROR;
+	}
+
+	tasklet_schedule(&chan->cleanup_tasklet);
+}
+
+static dma_cookie_t ccp_tx_submit(struct dma_async_tx_descriptor *tx_desc)
+{
+	struct ccp_dma_desc *desc = container_of(tx_desc, struct ccp_dma_desc,
+						 tx_desc);
+	struct ccp_dma_chan *chan;
+	dma_cookie_t cookie;
+	unsigned long flags;
+
+	chan = container_of(tx_desc->chan, struct ccp_dma_chan, dma_chan);
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	cookie = dma_cookie_assign(tx_desc);
+	list_move_tail(&desc->entry, &chan->pending);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	dev_dbg(chan->ccp->dev, "%s - added tx descriptor %d to pending list\n",
+		__func__, cookie);
+
+	return cookie;
+}
+
+static struct ccp_dma_cmd *ccp_alloc_dma_cmd(struct ccp_dma_chan *chan)
+{
+	struct ccp_dma_cmd *cmd;
+
+	cmd = kmem_cache_alloc(chan->ccp->dma_cmd_cache, GFP_NOWAIT);
+	if (cmd)
+		memset(cmd, 0, sizeof(*cmd));
+
+	return cmd;
+}
+
+static struct ccp_dma_desc *ccp_alloc_dma_desc(struct ccp_dma_chan *chan,
+					       unsigned long flags)
+{
+	struct ccp_dma_desc *desc;
+
+	desc = kmem_cache_zalloc(chan->ccp->dma_desc_cache, GFP_NOWAIT);
+	if (!desc)
+		return NULL;
+
+	dma_async_tx_descriptor_init(&desc->tx_desc, &chan->dma_chan);
+	desc->tx_desc.flags = flags;
+	desc->tx_desc.tx_submit = ccp_tx_submit;
+	desc->ccp = chan->ccp;
+	INIT_LIST_HEAD(&desc->entry);
+	INIT_LIST_HEAD(&desc->pending);
+	INIT_LIST_HEAD(&desc->active);
+	desc->status = DMA_IN_PROGRESS;
+
+	return desc;
+}
+
+static struct ccp_dma_desc *ccp_create_desc(struct dma_chan *dma_chan,
+					    struct scatterlist *dst_sg,
+					    unsigned int dst_nents,
+					    struct scatterlist *src_sg,
+					    unsigned int src_nents,
+					    unsigned long flags)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_device *ccp = chan->ccp;
+	struct ccp_dma_desc *desc;
+	struct ccp_dma_cmd *cmd;
+	struct ccp_cmd *ccp_cmd;
+	struct ccp_passthru_nomap_engine *ccp_pt;
+	unsigned int src_offset, src_len;
+	unsigned int dst_offset, dst_len;
+	unsigned int len;
+	unsigned long sflags;
+	size_t total_len;
+
+	if (!dst_sg || !src_sg)
+		return NULL;
+
+	if (!dst_nents || !src_nents)
+		return NULL;
+
+	desc = ccp_alloc_dma_desc(chan, flags);
+	if (!desc)
+		return NULL;
+
+	total_len = 0;
+
+	src_len = sg_dma_len(src_sg);
+	src_offset = 0;
+
+	dst_len = sg_dma_len(dst_sg);
+	dst_offset = 0;
+
+	while (true) {
+		if (!src_len) {
+			src_nents--;
+			if (!src_nents)
+				break;
+
+			src_sg = sg_next(src_sg);
+			if (!src_sg)
+				break;
+
+			src_len = sg_dma_len(src_sg);
+			src_offset = 0;
+			continue;
+		}
+
+		if (!dst_len) {
+			dst_nents--;
+			if (!dst_nents)
+				break;
+
+			dst_sg = sg_next(dst_sg);
+			if (!dst_sg)
+				break;
+
+			dst_len = sg_dma_len(dst_sg);
+			dst_offset = 0;
+			continue;
+		}
+
+		len = min(dst_len, src_len);
+
+		cmd = ccp_alloc_dma_cmd(chan);
+		if (!cmd)
+			goto err;
+
+		ccp_cmd = &cmd->ccp_cmd;
+		ccp_cmd->ccp = chan->ccp;
+		ccp_pt = &ccp_cmd->u.passthru_nomap;
+		ccp_cmd->flags = CCP_CMD_MAY_BACKLOG;
+		ccp_cmd->flags |= CCP_CMD_PASSTHRU_NO_DMA_MAP;
+		ccp_cmd->engine = CCP_ENGINE_PASSTHRU;
+		ccp_pt->bit_mod = CCP_PASSTHRU_BITWISE_NOOP;
+		ccp_pt->byte_swap = CCP_PASSTHRU_BYTESWAP_NOOP;
+		ccp_pt->src_dma = sg_dma_address(src_sg) + src_offset;
+		ccp_pt->dst_dma = sg_dma_address(dst_sg) + dst_offset;
+		ccp_pt->src_len = len;
+		ccp_pt->final = 1;
+		ccp_cmd->callback = ccp_cmd_callback;
+		ccp_cmd->data = desc;
+
+		list_add_tail(&cmd->entry, &desc->pending);
+
+		dev_dbg(ccp->dev,
+			"%s - cmd=%p, src=%pad, dst=%pad, len=%llu\n", __func__,
+			cmd, &ccp_pt->src_dma,
+			&ccp_pt->dst_dma, ccp_pt->src_len);
+
+		total_len += len;
+
+		src_len -= len;
+		src_offset += len;
+
+		dst_len -= len;
+		dst_offset += len;
+	}
+
+	desc->len = total_len;
+
+	if (list_empty(&desc->pending))
+		goto err;
+
+	dev_dbg(ccp->dev, "%s - desc=%p\n", __func__, desc);
+
+	spin_lock_irqsave(&chan->lock, sflags);
+
+	list_add_tail(&desc->entry, &chan->created);
+
+	spin_unlock_irqrestore(&chan->lock, sflags);
+
+	return desc;
+
+err:
+	ccp_free_cmd_resources(ccp, &desc->pending);
+	kmem_cache_free(ccp->dma_desc_cache, desc);
+
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *ccp_prep_dma_memcpy(
+	struct dma_chan *dma_chan, dma_addr_t dst, dma_addr_t src, size_t len,
+	unsigned long flags)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_dma_desc *desc;
+	struct scatterlist dst_sg, src_sg;
+
+	dev_dbg(chan->ccp->dev,
+		"%s - src=%pad, dst=%pad, len=%zu, flags=%#lx\n",
+		__func__, &src, &dst, len, flags);
+
+	sg_init_table(&dst_sg, 1);
+	sg_dma_address(&dst_sg) = dst;
+	sg_dma_len(&dst_sg) = len;
+
+	sg_init_table(&src_sg, 1);
+	sg_dma_address(&src_sg) = src;
+	sg_dma_len(&src_sg) = len;
+
+	desc = ccp_create_desc(dma_chan, &dst_sg, 1, &src_sg, 1, flags);
+	if (!desc)
+		return NULL;
+
+	return &desc->tx_desc;
+}
+
+static struct dma_async_tx_descriptor *ccp_prep_dma_interrupt(
+	struct dma_chan *dma_chan, unsigned long flags)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_dma_desc *desc;
+
+	desc = ccp_alloc_dma_desc(chan, flags);
+	if (!desc)
+		return NULL;
+
+	return &desc->tx_desc;
+}
+
+static void ccp_issue_pending(struct dma_chan *dma_chan)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_dma_desc *desc;
+	unsigned long flags;
+
+	dev_dbg(chan->ccp->dev, "%s\n", __func__);
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	desc = __ccp_pending_to_active(chan);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	/* If there was nothing active, start processing */
+	if (desc)
+		ccp_cmd_callback(desc, 0);
+}
+
+static enum dma_status ccp_tx_status(struct dma_chan *dma_chan,
+				     dma_cookie_t cookie,
+				     struct dma_tx_state *state)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_dma_desc *desc;
+	enum dma_status ret;
+	unsigned long flags;
+
+	if (chan->status == DMA_PAUSED) {
+		ret = DMA_PAUSED;
+		goto out;
+	}
+
+	ret = dma_cookie_status(dma_chan, cookie, state);
+	if (ret == DMA_COMPLETE) {
+		spin_lock_irqsave(&chan->lock, flags);
+
+		/* Get status from complete chain, if still there */
+		list_for_each_entry(desc, &chan->complete, entry) {
+			if (desc->tx_desc.cookie != cookie)
+				continue;
+
+			ret = desc->status;
+			break;
+		}
+
+		spin_unlock_irqrestore(&chan->lock, flags);
+	}
+
+out:
+	dev_dbg(chan->ccp->dev, "%s - %u\n", __func__, ret);
+
+	return ret;
+}
+
+static int ccp_pause(struct dma_chan *dma_chan)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+
+	chan->status = DMA_PAUSED;
+
+	/*TODO: Wait for active DMA to complete before returning? */
+
+	return 0;
+}
+
+static int ccp_resume(struct dma_chan *dma_chan)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	struct ccp_dma_desc *desc;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	desc = list_first_entry_or_null(&chan->active, struct ccp_dma_desc,
+					entry);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	/* Indicate the channel is running again */
+	chan->status = DMA_IN_PROGRESS;
+
+	/* If there was something active, re-start */
+	if (desc)
+		ccp_cmd_callback(desc, 0);
+
+	return 0;
+}
+
+static int ccp_terminate_all(struct dma_chan *dma_chan)
+{
+	struct ccp_dma_chan *chan = container_of(dma_chan, struct ccp_dma_chan,
+						 dma_chan);
+	unsigned long flags;
+
+	dev_dbg(chan->ccp->dev, "%s\n", __func__);
+
+	/*TODO: Wait for active DMA to complete before continuing */
+
+	spin_lock_irqsave(&chan->lock, flags);
+
+	/*TODO: Purge the complete list? */
+	ccp_free_desc_resources(chan->ccp, &chan->active);
+	ccp_free_desc_resources(chan->ccp, &chan->pending);
+	ccp_free_desc_resources(chan->ccp, &chan->created);
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return 0;
+}
+
+static void ccp_dma_release(struct ccp_device *ccp)
+{
+	struct ccp_dma_chan *chan;
+	struct dma_chan *dma_chan;
+	unsigned int i;
+
+	for (i = 0; i < ccp->cmd_q_count; i++) {
+		chan = ccp->ccp_dma_chan + i;
+		dma_chan = &chan->dma_chan;
+
+		tasklet_kill(&chan->cleanup_tasklet);
+		list_del_rcu(&dma_chan->device_node);
+	}
+}
+
+static void ccp_dma_release_channels(struct ccp_device *ccp)
+{
+	struct ccp_dma_chan *chan;
+	struct dma_chan *dma_chan;
+	unsigned int i;
+
+	for (i = 0; i < ccp->cmd_q_count; i++) {
+		chan = ccp->ccp_dma_chan + i;
+		dma_chan = &chan->dma_chan;
+
+		if (dma_chan->client_count)
+			dma_release_channel(dma_chan);
+	}
+}
+
+int ccp_dmaengine_register(struct ccp_device *ccp)
+{
+	struct ccp_dma_chan *chan;
+	struct dma_device *dma_dev = &ccp->dma_dev;
+	struct dma_chan *dma_chan;
+	char *dma_cmd_cache_name;
+	char *dma_desc_cache_name;
+	unsigned int i;
+	int ret;
+
+	if (!dmaengine)
+		return 0;
+
+	ccp->ccp_dma_chan = devm_kcalloc(ccp->dev, ccp->cmd_q_count,
+					 sizeof(*(ccp->ccp_dma_chan)),
+					 GFP_KERNEL);
+	if (!ccp->ccp_dma_chan)
+		return -ENOMEM;
+
+	dma_cmd_cache_name = devm_kasprintf(ccp->dev, GFP_KERNEL,
+					    "%s-dmaengine-cmd-cache",
+					    ccp->name);
+	if (!dma_cmd_cache_name)
+		return -ENOMEM;
+
+	ccp->dma_cmd_cache = kmem_cache_create(dma_cmd_cache_name,
+					       sizeof(struct ccp_dma_cmd),
+					       sizeof(void *),
+					       SLAB_HWCACHE_ALIGN, NULL);
+	if (!ccp->dma_cmd_cache)
+		return -ENOMEM;
+
+	dma_desc_cache_name = devm_kasprintf(ccp->dev, GFP_KERNEL,
+					     "%s-dmaengine-desc-cache",
+					     ccp->name);
+	if (!dma_desc_cache_name) {
+		ret = -ENOMEM;
+		goto err_cache;
+	}
+
+	ccp->dma_desc_cache = kmem_cache_create(dma_desc_cache_name,
+						sizeof(struct ccp_dma_desc),
+						sizeof(void *),
+						SLAB_HWCACHE_ALIGN, NULL);
+	if (!ccp->dma_desc_cache) {
+		ret = -ENOMEM;
+		goto err_cache;
+	}
+
+	dma_dev->dev = ccp->dev;
+	dma_dev->src_addr_widths = CCP_DMA_WIDTH(dma_get_mask(ccp->dev));
+	dma_dev->dst_addr_widths = CCP_DMA_WIDTH(dma_get_mask(ccp->dev));
+	dma_dev->directions = DMA_MEM_TO_MEM;
+	dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+	dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
+	dma_cap_set(DMA_INTERRUPT, dma_dev->cap_mask);
+
+	/* The DMA channels for this device can be set to public or private,
+	 * and overridden by the module parameter dma_chan_attr.
+	 * Default: according to the value in vdata (dma_chan_attr=0)
+	 * dma_chan_attr=0x1: all channels private (override vdata)
+	 * dma_chan_attr=0x2: all channels public (override vdata)
+	 */
+	if (ccp_get_dma_chan_attr(ccp) == DMA_PRIVATE)
+		dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
+
+	INIT_LIST_HEAD(&dma_dev->channels);
+	for (i = 0; i < ccp->cmd_q_count; i++) {
+		chan = ccp->ccp_dma_chan + i;
+		dma_chan = &chan->dma_chan;
+
+		chan->ccp = ccp;
+
+		spin_lock_init(&chan->lock);
+		INIT_LIST_HEAD(&chan->created);
+		INIT_LIST_HEAD(&chan->pending);
+		INIT_LIST_HEAD(&chan->active);
+		INIT_LIST_HEAD(&chan->complete);
+
+		tasklet_init(&chan->cleanup_tasklet, ccp_do_cleanup,
+			     (unsigned long)chan);
+
+		dma_chan->device = dma_dev;
+		dma_cookie_init(dma_chan);
+
+		list_add_tail(&dma_chan->device_node, &dma_dev->channels);
+	}
+
+	dma_dev->device_free_chan_resources = ccp_free_chan_resources;
+	dma_dev->device_prep_dma_memcpy = ccp_prep_dma_memcpy;
+	dma_dev->device_prep_dma_interrupt = ccp_prep_dma_interrupt;
+	dma_dev->device_issue_pending = ccp_issue_pending;
+	dma_dev->device_tx_status = ccp_tx_status;
+	dma_dev->device_pause = ccp_pause;
+	dma_dev->device_resume = ccp_resume;
+	dma_dev->device_terminate_all = ccp_terminate_all;
+
+	ret = dma_async_device_register(dma_dev);
+	if (ret)
+		goto err_reg;
+
+	return 0;
+
+err_reg:
+	ccp_dma_release(ccp);
+	kmem_cache_destroy(ccp->dma_desc_cache);
+
+err_cache:
+	kmem_cache_destroy(ccp->dma_cmd_cache);
+
+	return ret;
+}
+
+void ccp_dmaengine_unregister(struct ccp_device *ccp)
+{
+	struct dma_device *dma_dev = &ccp->dma_dev;
+
+	if (!dmaengine)
+		return;
+
+	ccp_dma_release_channels(ccp);
+	dma_async_device_unregister(dma_dev);
+	ccp_dma_release(ccp);
+
+	kmem_cache_destroy(ccp->dma_desc_cache);
+	kmem_cache_destroy(ccp->dma_cmd_cache);
+}