Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 799 insertions, 0 deletions

diff --git a/drivers/dma/mic_x100_dma.c b/drivers/dma/mic_x100_dma.c
new file mode 100644
index 000000000..adfd316db
--- /dev/null
+++ b/drivers/dma/mic_x100_dma.c
@@ -0,0 +1,799 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2014 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.
+ *
+ * The full GNU General Public License is included in this distribution in
+ * the file called "COPYING".
+ *
+ * Intel MIC X100 DMA Driver.
+ *
+ * Adapted from IOAT dma driver.
+ */
+#include <linux/module.h>
+#include <linux/io.h>
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+
+#include "mic_x100_dma.h"
+
+#define MIC_DMA_MAX_XFER_SIZE_CARD  (1 * 1024 * 1024 -\
+				       MIC_DMA_ALIGN_BYTES)
+#define MIC_DMA_MAX_XFER_SIZE_HOST  (1 * 1024 * 1024 >> 1)
+#define MIC_DMA_DESC_TYPE_SHIFT	60
+#define MIC_DMA_MEMCPY_LEN_SHIFT 46
+#define MIC_DMA_STAT_INTR_SHIFT 59
+
+/* high-water mark for pushing dma descriptors */
+static int mic_dma_pending_level = 4;
+
+/* Status descriptor is used to write a 64 bit value to a memory location */
+enum mic_dma_desc_format_type {
+	MIC_DMA_MEMCPY = 1,
+	MIC_DMA_STATUS,
+};
+
+static inline u32 mic_dma_hw_ring_inc(u32 val)
+{
+	return (val + 1) % MIC_DMA_DESC_RX_SIZE;
+}
+
+static inline u32 mic_dma_hw_ring_dec(u32 val)
+{
+	return val ? val - 1 : MIC_DMA_DESC_RX_SIZE - 1;
+}
+
+static inline void mic_dma_hw_ring_inc_head(struct mic_dma_chan *ch)
+{
+	ch->head = mic_dma_hw_ring_inc(ch->head);
+}
+
+/* Prepare a memcpy desc */
+static inline void mic_dma_memcpy_desc(struct mic_dma_desc *desc,
+	dma_addr_t src_phys, dma_addr_t dst_phys, u64 size)
+{
+	u64 qw0, qw1;
+
+	qw0 = src_phys;
+	qw0 |= (size >> MIC_DMA_ALIGN_SHIFT) << MIC_DMA_MEMCPY_LEN_SHIFT;
+	qw1 = MIC_DMA_MEMCPY;
+	qw1 <<= MIC_DMA_DESC_TYPE_SHIFT;
+	qw1 |= dst_phys;
+	desc->qw0 = qw0;
+	desc->qw1 = qw1;
+}
+
+/* Prepare a status desc. with @data to be written at @dst_phys */
+static inline void mic_dma_prep_status_desc(struct mic_dma_desc *desc, u64 data,
+	dma_addr_t dst_phys, bool generate_intr)
+{
+	u64 qw0, qw1;
+
+	qw0 = data;
+	qw1 = (u64) MIC_DMA_STATUS << MIC_DMA_DESC_TYPE_SHIFT | dst_phys;
+	if (generate_intr)
+		qw1 |= (1ULL << MIC_DMA_STAT_INTR_SHIFT);
+	desc->qw0 = qw0;
+	desc->qw1 = qw1;
+}
+
+static void mic_dma_cleanup(struct mic_dma_chan *ch)
+{
+	struct dma_async_tx_descriptor *tx;
+	u32 tail;
+	u32 last_tail;
+
+	spin_lock(&ch->cleanup_lock);
+	tail = mic_dma_read_cmp_cnt(ch);
+	/*
+	 * This is the barrier pair for smp_wmb() in fn.
+	 * mic_dma_tx_submit_unlock. It's required so that we read the
+	 * updated cookie value from tx->cookie.
+	 */
+	smp_rmb();
+	for (last_tail = ch->last_tail; tail != last_tail;) {
+		tx = &ch->tx_array[last_tail];
+		if (tx->cookie) {
+			dma_cookie_complete(tx);
+			dmaengine_desc_get_callback_invoke(tx, NULL);
+			tx->callback = NULL;
+		}
+		last_tail = mic_dma_hw_ring_inc(last_tail);
+	}
+	/* finish all completion callbacks before incrementing tail */
+	smp_mb();
+	ch->last_tail = last_tail;
+	spin_unlock(&ch->cleanup_lock);
+}
+
+static u32 mic_dma_ring_count(u32 head, u32 tail)
+{
+	u32 count;
+
+	if (head >= tail)
+		count = (tail - 0) + (MIC_DMA_DESC_RX_SIZE - head);
+	else
+		count = tail - head;
+	return count - 1;
+}
+
+/* Returns the num. of free descriptors on success, -ENOMEM on failure */
+static int mic_dma_avail_desc_ring_space(struct mic_dma_chan *ch, int required)
+{
+	struct device *dev = mic_dma_ch_to_device(ch);
+	u32 count;
+
+	count = mic_dma_ring_count(ch->head, ch->last_tail);
+	if (count < required) {
+		mic_dma_cleanup(ch);
+		count = mic_dma_ring_count(ch->head, ch->last_tail);
+	}
+
+	if (count < required) {
+		dev_dbg(dev, "Not enough desc space");
+		dev_dbg(dev, "%s %d required=%u, avail=%u\n",
+			__func__, __LINE__, required, count);
+		return -ENOMEM;
+	} else {
+		return count;
+	}
+}
+
+/* Program memcpy descriptors into the descriptor ring and update s/w head ptr*/
+static int mic_dma_prog_memcpy_desc(struct mic_dma_chan *ch, dma_addr_t src,
+				    dma_addr_t dst, size_t len)
+{
+	size_t current_transfer_len;
+	size_t max_xfer_size = to_mic_dma_dev(ch)->max_xfer_size;
+	/* 3 is added to make sure we have enough space for status desc */
+	int num_desc = len / max_xfer_size + 3;
+	int ret;
+
+	if (len % max_xfer_size)
+		num_desc++;
+
+	ret = mic_dma_avail_desc_ring_space(ch, num_desc);
+	if (ret < 0)
+		return ret;
+	do {
+		current_transfer_len = min(len, max_xfer_size);
+		mic_dma_memcpy_desc(&ch->desc_ring[ch->head],
+				    src, dst, current_transfer_len);
+		mic_dma_hw_ring_inc_head(ch);
+		len -= current_transfer_len;
+		dst = dst + current_transfer_len;
+		src = src + current_transfer_len;
+	} while (len > 0);
+	return 0;
+}
+
+/* It's a h/w quirk and h/w needs 2 status descriptors for every status desc */
+static void mic_dma_prog_intr(struct mic_dma_chan *ch)
+{
+	mic_dma_prep_status_desc(&ch->desc_ring[ch->head], 0,
+				 ch->status_dest_micpa, false);
+	mic_dma_hw_ring_inc_head(ch);
+	mic_dma_prep_status_desc(&ch->desc_ring[ch->head], 0,
+				 ch->status_dest_micpa, true);
+	mic_dma_hw_ring_inc_head(ch);
+}
+
+/* Wrapper function to program memcpy descriptors/status descriptors */
+static int mic_dma_do_dma(struct mic_dma_chan *ch, int flags, dma_addr_t src,
+			  dma_addr_t dst, size_t len)
+{
+	if (len && -ENOMEM == mic_dma_prog_memcpy_desc(ch, src, dst, len)) {
+		return -ENOMEM;
+	} else {
+		/* 3 is the maximum number of status descriptors */
+		int ret = mic_dma_avail_desc_ring_space(ch, 3);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Above mic_dma_prog_memcpy_desc() makes sure we have enough space */
+	if (flags & DMA_PREP_FENCE) {
+		mic_dma_prep_status_desc(&ch->desc_ring[ch->head], 0,
+					 ch->status_dest_micpa, false);
+		mic_dma_hw_ring_inc_head(ch);
+	}
+
+	if (flags & DMA_PREP_INTERRUPT)
+		mic_dma_prog_intr(ch);
+
+	return 0;
+}
+
+static inline void mic_dma_issue_pending(struct dma_chan *ch)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+
+	spin_lock(&mic_ch->issue_lock);
+	/*
+	 * Write to head triggers h/w to act on the descriptors.
+	 * On MIC, writing the same head value twice causes
+	 * a h/w error. On second write, h/w assumes we filled
+	 * the entire ring & overwrote some of the descriptors.
+	 */
+	if (mic_ch->issued == mic_ch->submitted)
+		goto out;
+	mic_ch->issued = mic_ch->submitted;
+	/*
+	 * make descriptor updates visible before advancing head,
+	 * this is purposefully not smp_wmb() since we are also
+	 * publishing the descriptor updates to a dma device
+	 */
+	wmb();
+	mic_dma_write_reg(mic_ch, MIC_DMA_REG_DHPR, mic_ch->issued);
+out:
+	spin_unlock(&mic_ch->issue_lock);
+}
+
+static inline void mic_dma_update_pending(struct mic_dma_chan *ch)
+{
+	if (mic_dma_ring_count(ch->issued, ch->submitted)
+			> mic_dma_pending_level)
+		mic_dma_issue_pending(&ch->api_ch);
+}
+
+static dma_cookie_t mic_dma_tx_submit_unlock(struct dma_async_tx_descriptor *tx)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(tx->chan);
+	dma_cookie_t cookie;
+
+	dma_cookie_assign(tx);
+	cookie = tx->cookie;
+	/*
+	 * We need an smp write barrier here because another CPU might see
+	 * an update to submitted and update h/w head even before we
+	 * assigned a cookie to this tx.
+	 */
+	smp_wmb();
+	mic_ch->submitted = mic_ch->head;
+	spin_unlock(&mic_ch->prep_lock);
+	mic_dma_update_pending(mic_ch);
+	return cookie;
+}
+
+static inline struct dma_async_tx_descriptor *
+allocate_tx(struct mic_dma_chan *ch)
+{
+	u32 idx = mic_dma_hw_ring_dec(ch->head);
+	struct dma_async_tx_descriptor *tx = &ch->tx_array[idx];
+
+	dma_async_tx_descriptor_init(tx, &ch->api_ch);
+	tx->tx_submit = mic_dma_tx_submit_unlock;
+	return tx;
+}
+
+/* Program a status descriptor with dst as address and value to be written */
+static struct dma_async_tx_descriptor *
+mic_dma_prep_status_lock(struct dma_chan *ch, dma_addr_t dst, u64 src_val,
+			 unsigned long flags)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+	int result;
+
+	spin_lock(&mic_ch->prep_lock);
+	result = mic_dma_avail_desc_ring_space(mic_ch, 4);
+	if (result < 0)
+		goto error;
+	mic_dma_prep_status_desc(&mic_ch->desc_ring[mic_ch->head], src_val, dst,
+				 false);
+	mic_dma_hw_ring_inc_head(mic_ch);
+	result = mic_dma_do_dma(mic_ch, flags, 0, 0, 0);
+	if (result < 0)
+		goto error;
+
+	return allocate_tx(mic_ch);
+error:
+	dev_err(mic_dma_ch_to_device(mic_ch),
+		"Error enqueueing dma status descriptor, error=%d\n", result);
+	spin_unlock(&mic_ch->prep_lock);
+	return NULL;
+}
+
+/*
+ * Prepare a memcpy descriptor to be added to the ring.
+ * Note that the temporary descriptor adds an extra overhead of copying the
+ * descriptor to ring. So, we copy directly to the descriptor ring
+ */
+static struct dma_async_tx_descriptor *
+mic_dma_prep_memcpy_lock(struct dma_chan *ch, dma_addr_t dma_dest,
+			 dma_addr_t dma_src, size_t len, unsigned long flags)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+	struct device *dev = mic_dma_ch_to_device(mic_ch);
+	int result;
+
+	if (!len && !flags)
+		return NULL;
+
+	spin_lock(&mic_ch->prep_lock);
+	result = mic_dma_do_dma(mic_ch, flags, dma_src, dma_dest, len);
+	if (result >= 0)
+		return allocate_tx(mic_ch);
+	dev_err(dev, "Error enqueueing dma, error=%d\n", result);
+	spin_unlock(&mic_ch->prep_lock);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+mic_dma_prep_interrupt_lock(struct dma_chan *ch, unsigned long flags)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+	int ret;
+
+	spin_lock(&mic_ch->prep_lock);
+	ret = mic_dma_do_dma(mic_ch, flags, 0, 0, 0);
+	if (!ret)
+		return allocate_tx(mic_ch);
+	spin_unlock(&mic_ch->prep_lock);
+	return NULL;
+}
+
+/* Return the status of the transaction */
+static enum dma_status
+mic_dma_tx_status(struct dma_chan *ch, dma_cookie_t cookie,
+		  struct dma_tx_state *txstate)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+
+	if (DMA_COMPLETE != dma_cookie_status(ch, cookie, txstate))
+		mic_dma_cleanup(mic_ch);
+
+	return dma_cookie_status(ch, cookie, txstate);
+}
+
+static irqreturn_t mic_dma_thread_fn(int irq, void *data)
+{
+	mic_dma_cleanup((struct mic_dma_chan *)data);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t mic_dma_intr_handler(int irq, void *data)
+{
+	struct mic_dma_chan *ch = ((struct mic_dma_chan *)data);
+
+	mic_dma_ack_interrupt(ch);
+	return IRQ_WAKE_THREAD;
+}
+
+static int mic_dma_alloc_desc_ring(struct mic_dma_chan *ch)
+{
+	u64 desc_ring_size = MIC_DMA_DESC_RX_SIZE * sizeof(*ch->desc_ring);
+	struct device *dev = &to_mbus_device(ch)->dev;
+
+	desc_ring_size = ALIGN(desc_ring_size, MIC_DMA_ALIGN_BYTES);
+	ch->desc_ring = kzalloc(desc_ring_size, GFP_KERNEL);
+
+	if (!ch->desc_ring)
+		return -ENOMEM;
+
+	ch->desc_ring_micpa = dma_map_single(dev, ch->desc_ring,
+					     desc_ring_size, DMA_BIDIRECTIONAL);
+	if (dma_mapping_error(dev, ch->desc_ring_micpa))
+		goto map_error;
+
+	ch->tx_array = vzalloc(array_size(MIC_DMA_DESC_RX_SIZE,
+					  sizeof(*ch->tx_array)));
+	if (!ch->tx_array)
+		goto tx_error;
+	return 0;
+tx_error:
+	dma_unmap_single(dev, ch->desc_ring_micpa, desc_ring_size,
+			 DMA_BIDIRECTIONAL);
+map_error:
+	kfree(ch->desc_ring);
+	return -ENOMEM;
+}
+
+static void mic_dma_free_desc_ring(struct mic_dma_chan *ch)
+{
+	u64 desc_ring_size = MIC_DMA_DESC_RX_SIZE * sizeof(*ch->desc_ring);
+
+	vfree(ch->tx_array);
+	desc_ring_size = ALIGN(desc_ring_size, MIC_DMA_ALIGN_BYTES);
+	dma_unmap_single(&to_mbus_device(ch)->dev, ch->desc_ring_micpa,
+			 desc_ring_size, DMA_BIDIRECTIONAL);
+	kfree(ch->desc_ring);
+	ch->desc_ring = NULL;
+}
+
+static void mic_dma_free_status_dest(struct mic_dma_chan *ch)
+{
+	dma_unmap_single(&to_mbus_device(ch)->dev, ch->status_dest_micpa,
+			 L1_CACHE_BYTES, DMA_BIDIRECTIONAL);
+	kfree(ch->status_dest);
+}
+
+static int mic_dma_alloc_status_dest(struct mic_dma_chan *ch)
+{
+	struct device *dev = &to_mbus_device(ch)->dev;
+
+	ch->status_dest = kzalloc(L1_CACHE_BYTES, GFP_KERNEL);
+	if (!ch->status_dest)
+		return -ENOMEM;
+	ch->status_dest_micpa = dma_map_single(dev, ch->status_dest,
+					L1_CACHE_BYTES, DMA_BIDIRECTIONAL);
+	if (dma_mapping_error(dev, ch->status_dest_micpa)) {
+		kfree(ch->status_dest);
+		ch->status_dest = NULL;
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static int mic_dma_check_chan(struct mic_dma_chan *ch)
+{
+	if (mic_dma_read_reg(ch, MIC_DMA_REG_DCHERR) ||
+	    mic_dma_read_reg(ch, MIC_DMA_REG_DSTAT) & MIC_DMA_CHAN_QUIESCE) {
+		mic_dma_disable_chan(ch);
+		mic_dma_chan_mask_intr(ch);
+		dev_err(mic_dma_ch_to_device(ch),
+			"%s %d error setting up mic dma chan %d\n",
+			__func__, __LINE__, ch->ch_num);
+		return -EBUSY;
+	}
+	return 0;
+}
+
+static int mic_dma_chan_setup(struct mic_dma_chan *ch)
+{
+	if (MIC_DMA_CHAN_MIC == ch->owner)
+		mic_dma_chan_set_owner(ch);
+	mic_dma_disable_chan(ch);
+	mic_dma_chan_mask_intr(ch);
+	mic_dma_write_reg(ch, MIC_DMA_REG_DCHERRMSK, 0);
+	mic_dma_chan_set_desc_ring(ch);
+	ch->last_tail = mic_dma_read_reg(ch, MIC_DMA_REG_DTPR);
+	ch->head = ch->last_tail;
+	ch->issued = 0;
+	mic_dma_chan_unmask_intr(ch);
+	mic_dma_enable_chan(ch);
+	return mic_dma_check_chan(ch);
+}
+
+static void mic_dma_chan_destroy(struct mic_dma_chan *ch)
+{
+	mic_dma_disable_chan(ch);
+	mic_dma_chan_mask_intr(ch);
+}
+
+static int mic_dma_setup_irq(struct mic_dma_chan *ch)
+{
+	ch->cookie =
+		to_mbus_hw_ops(ch)->request_threaded_irq(to_mbus_device(ch),
+			mic_dma_intr_handler, mic_dma_thread_fn,
+			"mic dma_channel", ch, ch->ch_num);
+	return PTR_ERR_OR_ZERO(ch->cookie);
+}
+
+static inline void mic_dma_free_irq(struct mic_dma_chan *ch)
+{
+	to_mbus_hw_ops(ch)->free_irq(to_mbus_device(ch), ch->cookie, ch);
+}
+
+static int mic_dma_chan_init(struct mic_dma_chan *ch)
+{
+	int ret = mic_dma_alloc_desc_ring(ch);
+
+	if (ret)
+		goto ring_error;
+	ret = mic_dma_alloc_status_dest(ch);
+	if (ret)
+		goto status_error;
+	ret = mic_dma_chan_setup(ch);
+	if (ret)
+		goto chan_error;
+	return ret;
+chan_error:
+	mic_dma_free_status_dest(ch);
+status_error:
+	mic_dma_free_desc_ring(ch);
+ring_error:
+	return ret;
+}
+
+static int mic_dma_drain_chan(struct mic_dma_chan *ch)
+{
+	struct dma_async_tx_descriptor *tx;
+	int err = 0;
+	dma_cookie_t cookie;
+
+	tx = mic_dma_prep_memcpy_lock(&ch->api_ch, 0, 0, 0, DMA_PREP_FENCE);
+	if (!tx) {
+		err = -ENOMEM;
+		goto error;
+	}
+
+	cookie = tx->tx_submit(tx);
+	if (dma_submit_error(cookie))
+		err = -ENOMEM;
+	else
+		err = dma_sync_wait(&ch->api_ch, cookie);
+	if (err) {
+		dev_err(mic_dma_ch_to_device(ch), "%s %d TO chan 0x%x\n",
+			__func__, __LINE__, ch->ch_num);
+		err = -EIO;
+	}
+error:
+	mic_dma_cleanup(ch);
+	return err;
+}
+
+static inline void mic_dma_chan_uninit(struct mic_dma_chan *ch)
+{
+	mic_dma_chan_destroy(ch);
+	mic_dma_cleanup(ch);
+	mic_dma_free_status_dest(ch);
+	mic_dma_free_desc_ring(ch);
+}
+
+static int mic_dma_init(struct mic_dma_device *mic_dma_dev,
+			enum mic_dma_chan_owner owner)
+{
+	int i, first_chan = mic_dma_dev->start_ch;
+	struct mic_dma_chan *ch;
+	int ret;
+
+	for (i = first_chan; i < first_chan + MIC_DMA_NUM_CHAN; i++) {
+		ch = &mic_dma_dev->mic_ch[i];
+		ch->ch_num = i;
+		ch->owner = owner;
+		spin_lock_init(&ch->cleanup_lock);
+		spin_lock_init(&ch->prep_lock);
+		spin_lock_init(&ch->issue_lock);
+		ret = mic_dma_setup_irq(ch);
+		if (ret)
+			goto error;
+	}
+	return 0;
+error:
+	for (i = i - 1; i >= first_chan; i--)
+		mic_dma_free_irq(ch);
+	return ret;
+}
+
+static void mic_dma_uninit(struct mic_dma_device *mic_dma_dev)
+{
+	int i, first_chan = mic_dma_dev->start_ch;
+	struct mic_dma_chan *ch;
+
+	for (i = first_chan; i < first_chan + MIC_DMA_NUM_CHAN; i++) {
+		ch = &mic_dma_dev->mic_ch[i];
+		mic_dma_free_irq(ch);
+	}
+}
+
+static int mic_dma_alloc_chan_resources(struct dma_chan *ch)
+{
+	int ret = mic_dma_chan_init(to_mic_dma_chan(ch));
+	if (ret)
+		return ret;
+	return MIC_DMA_DESC_RX_SIZE;
+}
+
+static void mic_dma_free_chan_resources(struct dma_chan *ch)
+{
+	struct mic_dma_chan *mic_ch = to_mic_dma_chan(ch);
+	mic_dma_drain_chan(mic_ch);
+	mic_dma_chan_uninit(mic_ch);
+}
+
+/* Set the fn. handlers and register the dma device with dma api */
+static int mic_dma_register_dma_device(struct mic_dma_device *mic_dma_dev,
+				       enum mic_dma_chan_owner owner)
+{
+	int i, first_chan = mic_dma_dev->start_ch;
+
+	dma_cap_zero(mic_dma_dev->dma_dev.cap_mask);
+	/*
+	 * This dma engine is not capable of host memory to host memory
+	 * transfers
+	 */
+	dma_cap_set(DMA_MEMCPY, mic_dma_dev->dma_dev.cap_mask);
+
+	if (MIC_DMA_CHAN_HOST == owner)
+		dma_cap_set(DMA_PRIVATE, mic_dma_dev->dma_dev.cap_mask);
+	mic_dma_dev->dma_dev.device_alloc_chan_resources =
+		mic_dma_alloc_chan_resources;
+	mic_dma_dev->dma_dev.device_free_chan_resources =
+		mic_dma_free_chan_resources;
+	mic_dma_dev->dma_dev.device_tx_status = mic_dma_tx_status;
+	mic_dma_dev->dma_dev.device_prep_dma_memcpy = mic_dma_prep_memcpy_lock;
+	mic_dma_dev->dma_dev.device_prep_dma_imm_data =
+		mic_dma_prep_status_lock;
+	mic_dma_dev->dma_dev.device_prep_dma_interrupt =
+		mic_dma_prep_interrupt_lock;
+	mic_dma_dev->dma_dev.device_issue_pending = mic_dma_issue_pending;
+	mic_dma_dev->dma_dev.copy_align = MIC_DMA_ALIGN_SHIFT;
+	INIT_LIST_HEAD(&mic_dma_dev->dma_dev.channels);
+	for (i = first_chan; i < first_chan + MIC_DMA_NUM_CHAN; i++) {
+		mic_dma_dev->mic_ch[i].api_ch.device = &mic_dma_dev->dma_dev;
+		dma_cookie_init(&mic_dma_dev->mic_ch[i].api_ch);
+		list_add_tail(&mic_dma_dev->mic_ch[i].api_ch.device_node,
+			      &mic_dma_dev->dma_dev.channels);
+	}
+	return dmaenginem_async_device_register(&mic_dma_dev->dma_dev);
+}
+
+/*
+ * Initializes dma channels and registers the dma device with the
+ * dma engine api.
+ */
+static struct mic_dma_device *mic_dma_dev_reg(struct mbus_device *mbdev,
+					      enum mic_dma_chan_owner owner)
+{
+	struct mic_dma_device *mic_dma_dev;
+	int ret;
+	struct device *dev = &mbdev->dev;
+
+	mic_dma_dev = devm_kzalloc(dev, sizeof(*mic_dma_dev), GFP_KERNEL);
+	if (!mic_dma_dev) {
+		ret = -ENOMEM;
+		goto alloc_error;
+	}
+	mic_dma_dev->mbdev = mbdev;
+	mic_dma_dev->dma_dev.dev = dev;
+	mic_dma_dev->mmio = mbdev->mmio_va;
+	if (MIC_DMA_CHAN_HOST == owner) {
+		mic_dma_dev->start_ch = 0;
+		mic_dma_dev->max_xfer_size = MIC_DMA_MAX_XFER_SIZE_HOST;
+	} else {
+		mic_dma_dev->start_ch = 4;
+		mic_dma_dev->max_xfer_size = MIC_DMA_MAX_XFER_SIZE_CARD;
+	}
+	ret = mic_dma_init(mic_dma_dev, owner);
+	if (ret)
+		goto init_error;
+	ret = mic_dma_register_dma_device(mic_dma_dev, owner);
+	if (ret)
+		goto reg_error;
+	return mic_dma_dev;
+reg_error:
+	mic_dma_uninit(mic_dma_dev);
+init_error:
+	mic_dma_dev = NULL;
+alloc_error:
+	dev_err(dev, "Error at %s %d ret=%d\n", __func__, __LINE__, ret);
+	return mic_dma_dev;
+}
+
+static void mic_dma_dev_unreg(struct mic_dma_device *mic_dma_dev)
+{
+	mic_dma_uninit(mic_dma_dev);
+}
+
+/* DEBUGFS CODE */
+static int mic_dma_reg_seq_show(struct seq_file *s, void *pos)
+{
+	struct mic_dma_device *mic_dma_dev = s->private;
+	int i, chan_num, first_chan = mic_dma_dev->start_ch;
+	struct mic_dma_chan *ch;
+
+	seq_printf(s, "SBOX_DCR: %#x\n",
+		   mic_dma_mmio_read(&mic_dma_dev->mic_ch[first_chan],
+				     MIC_DMA_SBOX_BASE + MIC_DMA_SBOX_DCR));
+	seq_puts(s, "DMA Channel Registers\n");
+	seq_printf(s, "%-10s| %-10s %-10s %-10s %-10s %-10s",
+		   "Channel", "DCAR", "DTPR", "DHPR", "DRAR_HI", "DRAR_LO");
+	seq_printf(s, " %-11s %-14s %-10s\n", "DCHERR", "DCHERRMSK", "DSTAT");
+	for (i = first_chan; i < first_chan + MIC_DMA_NUM_CHAN; i++) {
+		ch = &mic_dma_dev->mic_ch[i];
+		chan_num = ch->ch_num;
+		seq_printf(s, "%-10i| %-#10x %-#10x %-#10x %-#10x",
+			   chan_num,
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DCAR),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DTPR),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DHPR),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DRAR_HI));
+		seq_printf(s, " %-#10x %-#10x %-#14x %-#10x\n",
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DRAR_LO),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DCHERR),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DCHERRMSK),
+			   mic_dma_read_reg(ch, MIC_DMA_REG_DSTAT));
+	}
+	return 0;
+}
+
+static int mic_dma_reg_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, mic_dma_reg_seq_show, inode->i_private);
+}
+
+static int mic_dma_reg_debug_release(struct inode *inode, struct file *file)
+{
+	return single_release(inode, file);
+}
+
+static const struct file_operations mic_dma_reg_ops = {
+	.owner   = THIS_MODULE,
+	.open    = mic_dma_reg_debug_open,
+	.read    = seq_read,
+	.llseek  = seq_lseek,
+	.release = mic_dma_reg_debug_release
+};
+
+/* Debugfs parent dir */
+static struct dentry *mic_dma_dbg;
+
+static int mic_dma_driver_probe(struct mbus_device *mbdev)
+{
+	struct mic_dma_device *mic_dma_dev;
+	enum mic_dma_chan_owner owner;
+
+	if (MBUS_DEV_DMA_MIC == mbdev->id.device)
+		owner = MIC_DMA_CHAN_MIC;
+	else
+		owner = MIC_DMA_CHAN_HOST;
+
+	mic_dma_dev = mic_dma_dev_reg(mbdev, owner);
+	dev_set_drvdata(&mbdev->dev, mic_dma_dev);
+
+	if (mic_dma_dbg) {
+		mic_dma_dev->dbg_dir = debugfs_create_dir(dev_name(&mbdev->dev),
+							  mic_dma_dbg);
+		if (mic_dma_dev->dbg_dir)
+			debugfs_create_file("mic_dma_reg", 0444,
+					    mic_dma_dev->dbg_dir, mic_dma_dev,
+					    &mic_dma_reg_ops);
+	}
+	return 0;
+}
+
+static void mic_dma_driver_remove(struct mbus_device *mbdev)
+{
+	struct mic_dma_device *mic_dma_dev;
+
+	mic_dma_dev = dev_get_drvdata(&mbdev->dev);
+	debugfs_remove_recursive(mic_dma_dev->dbg_dir);
+	mic_dma_dev_unreg(mic_dma_dev);
+}
+
+static struct mbus_device_id id_table[] = {
+	{MBUS_DEV_DMA_MIC, MBUS_DEV_ANY_ID},
+	{MBUS_DEV_DMA_HOST, MBUS_DEV_ANY_ID},
+	{0},
+};
+
+static struct mbus_driver mic_dma_driver = {
+	.driver.name =	KBUILD_MODNAME,
+	.driver.owner =	THIS_MODULE,
+	.id_table = id_table,
+	.probe = mic_dma_driver_probe,
+	.remove = mic_dma_driver_remove,
+};
+
+static int __init mic_x100_dma_init(void)
+{
+	int rc = mbus_register_driver(&mic_dma_driver);
+	if (rc)
+		return rc;
+	mic_dma_dbg = debugfs_create_dir(KBUILD_MODNAME, NULL);
+	return 0;
+}
+
+static void __exit mic_x100_dma_exit(void)
+{
+	debugfs_remove_recursive(mic_dma_dbg);
+	mbus_unregister_driver(&mic_dma_driver);
+}
+
+module_init(mic_x100_dma_init);
+module_exit(mic_x100_dma_exit);
+
+MODULE_DEVICE_TABLE(mbus, id_table);
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("Intel(R) MIC X100 DMA Driver");
+MODULE_LICENSE("GPL v2");