diff --git a/drivers/dma/qcom/Makefile b/drivers/dma/qcom/Makefile
index bfea699..6bf9267 100644
--- a/drivers/dma/qcom/Makefile
+++ b/drivers/dma/qcom/Makefile
@@ -1,3 +1,5 @@
 obj-$(CONFIG_QCOM_BAM_DMA) += bam_dma.o
 obj-$(CONFIG_QCOM_HIDMA_MGMT) += hdma_mgmt.o
 hdma_mgmt-objs	 := hidma_mgmt.o hidma_mgmt_sys.o
+obj-$(CONFIG_QCOM_HIDMA) +=  hdma.o
+hdma-objs        := hidma_ll.o hidma.o
diff --git a/drivers/dma/qcom/hidma.h b/drivers/dma/qcom/hidma.h
index 231e306..c5eea65 100644
--- a/drivers/dma/qcom/hidma.h
+++ b/drivers/dma/qcom/hidma.h
@@ -1,7 +1,7 @@
 /*
  * Qualcomm Technologies HIDMA data structures
  *
- * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2014-2016, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
@@ -20,13 +20,13 @@
 #include <linux/interrupt.h>
 #include <linux/dmaengine.h>
 
-#define TRE_SIZE			32 /* each TRE is 32 bytes  */
-#define TRE_CFG_IDX			0
-#define TRE_LEN_IDX			1
-#define TRE_SRC_LOW_IDX		2
-#define TRE_SRC_HI_IDX			3
-#define TRE_DEST_LOW_IDX		4
-#define TRE_DEST_HI_IDX		5
+#define HIDMA_TRE_SIZE			32 /* each TRE is 32 bytes  */
+#define HIDMA_TRE_CFG_IDX		0
+#define HIDMA_TRE_LEN_IDX		1
+#define HIDMA_TRE_SRC_LOW_IDX		2
+#define HIDMA_TRE_SRC_HI_IDX		3
+#define HIDMA_TRE_DEST_LOW_IDX		4
+#define HIDMA_TRE_DEST_HI_IDX		5
 
 struct hidma_tx_status {
 	u8 err_info;			/* error record in this transfer    */
@@ -37,13 +37,13 @@ struct hidma_tre {
 	atomic_t allocated;		/* if this channel is allocated	    */
 	bool queued;			/* flag whether this is pending     */
 	u16 status;			/* status			    */
-	u32 chidx;			/* index of the tre		    */
+	u32 idx;			/* index of the tre		    */
 	u32 dma_sig;			/* signature of the tre		    */
 	const char *dev_name;		/* name of the device		    */
 	void (*callback)(void *data);	/* requester callback		    */
 	void *data;			/* Data associated with this channel*/
 	struct hidma_lldev *lldev;	/* lldma device pointer		    */
-	u32 tre_local[TRE_SIZE / sizeof(u32) + 1]; /* TRE local copy        */
+	u32 tre_local[HIDMA_TRE_SIZE / sizeof(u32) + 1]; /* TRE local copy  */
 	u32 tre_index;			/* the offset where this was written*/
 	u32 int_flags;			/* interrupt flags		    */
 };
diff --git a/drivers/dma/qcom/hidma_ll.c b/drivers/dma/qcom/hidma_ll.c
new file mode 100644
index 0000000..443a5a2
--- /dev/null
+++ b/drivers/dma/qcom/hidma_ll.c
@@ -0,0 +1,900 @@
+/*
+ * Qualcomm Technologies HIDMA DMA engine low level code
+ *
+ * Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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.
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/slab.h>
+#include <linux/interrupt.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/dma-mapping.h>
+#include <linux/delay.h>
+#include <linux/atomic.h>
+#include <linux/iopoll.h>
+#include <linux/kfifo.h>
+#include <linux/bitops.h>
+
+#include "hidma.h"
+
+#define HIDMA_EVRE_SIZE			16	/* each EVRE is 16 bytes */
+
+#define HIDMA_TRCA_CTRLSTS_REG			0x000
+#define HIDMA_TRCA_RING_LOW_REG		0x008
+#define HIDMA_TRCA_RING_HIGH_REG		0x00C
+#define HIDMA_TRCA_RING_LEN_REG		0x010
+#define HIDMA_TRCA_DOORBELL_REG		0x400
+
+#define HIDMA_EVCA_CTRLSTS_REG			0x000
+#define HIDMA_EVCA_INTCTRL_REG			0x004
+#define HIDMA_EVCA_RING_LOW_REG		0x008
+#define HIDMA_EVCA_RING_HIGH_REG		0x00C
+#define HIDMA_EVCA_RING_LEN_REG		0x010
+#define HIDMA_EVCA_WRITE_PTR_REG		0x020
+#define HIDMA_EVCA_DOORBELL_REG		0x400
+
+#define HIDMA_EVCA_IRQ_STAT_REG		0x100
+#define HIDMA_EVCA_IRQ_CLR_REG			0x108
+#define HIDMA_EVCA_IRQ_EN_REG			0x110
+
+#define HIDMA_EVRE_CFG_IDX			0
+
+#define HIDMA_EVRE_ERRINFO_BIT_POS		24
+#define HIDMA_EVRE_CODE_BIT_POS		28
+
+#define HIDMA_EVRE_ERRINFO_MASK		GENMASK(3, 0)
+#define HIDMA_EVRE_CODE_MASK			GENMASK(3, 0)
+
+#define HIDMA_CH_CONTROL_MASK			GENMASK(7, 0)
+#define HIDMA_CH_STATE_MASK			GENMASK(7, 0)
+#define HIDMA_CH_STATE_BIT_POS			0x8
+
+#define HIDMA_IRQ_EV_CH_EOB_IRQ_BIT_POS	0
+#define HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS	1
+#define HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS	9
+#define HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS	10
+#define HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS	11
+#define HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS	14
+
+#define ENABLE_IRQS (BIT(HIDMA_IRQ_EV_CH_EOB_IRQ_BIT_POS)	| \
+		BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS)		| \
+		BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)	| \
+		BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS)		| \
+		BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS)		| \
+		BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS))
+
+#define HIDMA_INCREMENT_ITERATOR(iter, size, ring_size)	\
+do {								\
+	iter += size;						\
+	if (iter >= ring_size)					\
+		iter -= ring_size;				\
+} while (0)
+
+#define HIDMA_CH_STATE(val)	\
+	((val >> HIDMA_CH_STATE_BIT_POS) & HIDMA_CH_STATE_MASK)
+
+enum ch_command {
+	HIDMA_CH_DISABLE = 0,
+	HIDMA_CH_ENABLE = 1,
+	HIDMA_CH_SUSPEND = 2,
+	HIDMA_CH_RESET = 9,
+};
+
+enum ch_state {
+	HIDMA_CH_DISABLED = 0,
+	HIDMA_CH_ENABLED = 1,
+	HIDMA_CH_RUNNING = 2,
+	HIDMA_CH_SUSPENDED = 3,
+	HIDMA_CH_STOPPED = 4,
+};
+
+enum tre_type {
+	HIDMA_TRE_MEMCPY = 3,
+};
+
+enum err_code {
+	HIDMA_EVRE_STATUS_COMPLETE = 1,
+	HIDMA_EVRE_STATUS_ERROR = 4,
+};
+
+void hidma_ll_free(struct hidma_lldev *lldev, u32 tre_ch)
+{
+	struct hidma_tre *tre;
+
+	if (tre_ch >= lldev->nr_tres) {
+		dev_err(lldev->dev, "invalid TRE number in free:%d", tre_ch);
+		return;
+	}
+
+	tre = &lldev->trepool[tre_ch];
+	if (atomic_read(&tre->allocated) != true) {
+		dev_err(lldev->dev, "trying to free an unused TRE:%d", tre_ch);
+		return;
+	}
+
+	atomic_set(&tre->allocated, 0);
+}
+
+int hidma_ll_request(struct hidma_lldev *lldev, u32 dma_sig,
+		     const char *dev_name,
+		     void (*callback)(void *data), void *data, u32 *tre_ch)
+{
+	unsigned int i;
+	struct hidma_tre *tre;
+	u32 *tre_local;
+
+	if (!tre_ch || !lldev)
+		return -EINVAL;
+
+	/* need to have at least one empty spot in the queue */
+	for (i = 0; i < lldev->nr_tres - 1; i++) {
+		if (atomic_add_unless(&lldev->trepool[i].allocated, 1, 1))
+			break;
+	}
+
+	if (i == (lldev->nr_tres - 1))
+		return -ENOMEM;
+
+	tre = &lldev->trepool[i];
+	tre->dma_sig = dma_sig;
+	tre->dev_name = dev_name;
+	tre->callback = callback;
+	tre->data = data;
+	tre->idx = i;
+	tre->status = 0;
+	tre->queued = 0;
+	lldev->tx_status_list[i].err_code = 0;
+	tre->lldev = lldev;
+	tre_local = &tre->tre_local[0];
+	tre_local[HIDMA_TRE_CFG_IDX] = HIDMA_TRE_MEMCPY;
+	tre_local[HIDMA_TRE_CFG_IDX] |= (lldev->chidx & 0xFF) << 8;
+	tre_local[HIDMA_TRE_CFG_IDX] |= BIT(16);	/* set IEOB */
+	*tre_ch = i;
+	if (callback)
+		callback(data);
+	return 0;
+}
+
+/*
+ * Multiple TREs may be queued and waiting in the
+ * pending queue.
+ */
+static void hidma_ll_tre_complete(unsigned long arg)
+{
+	struct hidma_lldev *lldev = (struct hidma_lldev *)arg;
+	struct hidma_tre *tre;
+
+	while (kfifo_out(&lldev->handoff_fifo, &tre, 1)) {
+		/* call the user if it has been read by the hardware */
+		if (tre->callback)
+			tre->callback(tre->data);
+	}
+}
+
+/*
+ * Called to handle the interrupt for the channel.
+ * Return a positive number if TRE or EVRE were consumed on this run.
+ * Return a positive number if there are pending TREs or EVREs.
+ * Return 0 if there is nothing to consume or no pending TREs/EVREs found.
+ */
+static int hidma_handle_tre_completion(struct hidma_lldev *lldev)
+{
+	struct hidma_tre *tre;
+	u32 evre_write_off;
+	u32 evre_ring_size = lldev->evre_ring_size;
+	u32 tre_ring_size = lldev->tre_ring_size;
+	u32 num_completed = 0, tre_iterator, evre_iterator;
+	unsigned long flags;
+
+	evre_write_off = readl_relaxed(lldev->evca + HIDMA_EVCA_WRITE_PTR_REG);
+	tre_iterator = lldev->tre_processed_off;
+	evre_iterator = lldev->evre_processed_off;
+
+	if ((evre_write_off > evre_ring_size) ||
+	    ((evre_write_off % HIDMA_EVRE_SIZE) != 0)) {
+		dev_err(lldev->dev, "HW reports invalid EVRE write offset\n");
+		return 0;
+	}
+
+	/*
+	 * By the time control reaches here the number of EVREs and TREs
+	 * may not match. Only consume the ones that hardware told us.
+	 */
+	while ((evre_iterator != evre_write_off)) {
+		u32 *current_evre = lldev->evre_ring + evre_iterator;
+		u32 cfg;
+		u8 err_info;
+
+		spin_lock_irqsave(&lldev->lock, flags);
+		tre = lldev->pending_tre_list[tre_iterator / HIDMA_TRE_SIZE];
+		if (!tre) {
+			spin_unlock_irqrestore(&lldev->lock, flags);
+			dev_warn(lldev->dev,
+				 "tre_index [%d] and tre out of sync\n",
+				 tre_iterator / HIDMA_TRE_SIZE);
+			HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE,
+						 tre_ring_size);
+			HIDMA_INCREMENT_ITERATOR(evre_iterator,
+						 HIDMA_EVRE_SIZE,
+						 evre_ring_size);
+			continue;
+		}
+		lldev->pending_tre_list[tre->tre_index] = NULL;
+
+		/*
+		 * Keep track of pending TREs that SW is expecting to receive
+		 * from HW. We got one now. Decrement our counter.
+		 */
+		lldev->pending_tre_count--;
+		if (lldev->pending_tre_count < 0) {
+			dev_warn(lldev->dev,
+				 "tre count mismatch on completion");
+			lldev->pending_tre_count = 0;
+		}
+
+		spin_unlock_irqrestore(&lldev->lock, flags);
+
+		cfg = current_evre[HIDMA_EVRE_CFG_IDX];
+		err_info = cfg >> HIDMA_EVRE_ERRINFO_BIT_POS;
+		err_info &= HIDMA_EVRE_ERRINFO_MASK;
+		lldev->tx_status_list[tre->idx].err_info = err_info;
+		lldev->tx_status_list[tre->idx].err_code =
+		    (cfg >> HIDMA_EVRE_CODE_BIT_POS) & HIDMA_EVRE_CODE_MASK;
+		tre->queued = 0;
+
+		kfifo_put(&lldev->handoff_fifo, tre);
+		tasklet_schedule(&lldev->task);
+
+		HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE,
+					 tre_ring_size);
+		HIDMA_INCREMENT_ITERATOR(evre_iterator, HIDMA_EVRE_SIZE,
+					 evre_ring_size);
+
+		/*
+		 * Read the new event descriptor written by the HW.
+		 * As we are processing the delivered events, other events
+		 * get queued to the SW for processing.
+		 */
+		evre_write_off =
+		    readl_relaxed(lldev->evca + HIDMA_EVCA_WRITE_PTR_REG);
+		num_completed++;
+	}
+
+	if (num_completed) {
+		u32 evre_read_off = (lldev->evre_processed_off +
+				     HIDMA_EVRE_SIZE * num_completed);
+		u32 tre_read_off = (lldev->tre_processed_off +
+				    HIDMA_TRE_SIZE * num_completed);
+
+		evre_read_off = evre_read_off % evre_ring_size;
+		tre_read_off = tre_read_off % tre_ring_size;
+
+		writel(evre_read_off, lldev->evca + HIDMA_EVCA_DOORBELL_REG);
+
+		/* record the last processed tre offset */
+		lldev->tre_processed_off = tre_read_off;
+		lldev->evre_processed_off = evre_read_off;
+	}
+
+	return num_completed;
+}
+
+void hidma_cleanup_pending_tre(struct hidma_lldev *lldev, u8 err_info,
+			       u8 err_code)
+{
+	u32 tre_iterator;
+	struct hidma_tre *tre;
+	u32 tre_ring_size = lldev->tre_ring_size;
+	int num_completed = 0;
+	u32 tre_read_off;
+	unsigned long flags;
+
+	tre_iterator = lldev->tre_processed_off;
+	while (lldev->pending_tre_count) {
+		int tre_index = tre_iterator / HIDMA_TRE_SIZE;
+
+		spin_lock_irqsave(&lldev->lock, flags);
+		tre = lldev->pending_tre_list[tre_index];
+		if (!tre) {
+			spin_unlock_irqrestore(&lldev->lock, flags);
+			HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE,
+						 tre_ring_size);
+			continue;
+		}
+		lldev->pending_tre_list[tre_index] = NULL;
+		lldev->pending_tre_count--;
+		if (lldev->pending_tre_count < 0) {
+			dev_warn(lldev->dev,
+				 "tre count mismatch on completion");
+			lldev->pending_tre_count = 0;
+		}
+		spin_unlock_irqrestore(&lldev->lock, flags);
+
+		lldev->tx_status_list[tre->idx].err_info = err_info;
+		lldev->tx_status_list[tre->idx].err_code = err_code;
+		tre->queued = 0;
+
+		kfifo_put(&lldev->handoff_fifo, tre);
+		tasklet_schedule(&lldev->task);
+
+		HIDMA_INCREMENT_ITERATOR(tre_iterator, HIDMA_TRE_SIZE,
+					 tre_ring_size);
+		num_completed++;
+	}
+	tre_read_off = (lldev->tre_processed_off +
+			HIDMA_TRE_SIZE * num_completed);
+
+	tre_read_off = tre_read_off % tre_ring_size;
+
+	/* record the last processed tre offset */
+	lldev->tre_processed_off = tre_read_off;
+}
+
+static int hidma_ll_reset(struct hidma_lldev *lldev)
+{
+	u32 val;
+	int ret;
+
+	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_RESET << 16;
+	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+
+	/*
+	 * Delay 10ms after reset to allow DMA logic to quiesce.
+	 * Do a polled read up to 1ms and 10ms maximum.
+	 */
+	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
+				 HIDMA_CH_STATE(val) == HIDMA_CH_DISABLED, 1000,
+				 10000);
+	if (ret) {
+		dev_err(lldev->dev, "transfer channel did not reset\n");
+		return ret;
+	}
+
+	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_RESET << 16;
+	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+
+	/*
+	 * Delay 10ms after reset to allow DMA logic to quiesce.
+	 * Do a polled read up to 1ms and 10ms maximum.
+	 */
+	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
+				 HIDMA_CH_STATE(val) == HIDMA_CH_DISABLED, 1000,
+				 10000);
+	if (ret)
+		return ret;
+
+	lldev->trch_state = HIDMA_CH_DISABLED;
+	lldev->evch_state = HIDMA_CH_DISABLED;
+	return 0;
+}
+
+static void hidma_ll_enable_irq(struct hidma_lldev *lldev, u32 irq_bits)
+{
+	writel(irq_bits, lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
+}
+
+/*
+ * The interrupt handler for HIDMA will try to consume as many pending
+ * EVRE from the event queue as possible. Each EVRE has an associated
+ * TRE that holds the user interface parameters. EVRE reports the
+ * result of the transaction. Hardware guarantees ordering between EVREs
+ * and TREs. We use last processed offset to figure out which TRE is
+ * associated with which EVRE. If two TREs are consumed by HW, the EVREs
+ * are in order in the event ring.
+ *
+ * This handler will do a one pass for consuming EVREs. Other EVREs may
+ * be delivered while we are working. It will try to consume incoming
+ * EVREs one more time and return.
+ *
+ * For unprocessed EVREs, hardware will trigger another interrupt until
+ * all the interrupt bits are cleared.
+ *
+ * Hardware guarantees that by the time interrupt is observed, all data
+ * transactions in flight are delivered to their respective places and
+ * are visible to the CPU.
+ *
+ * On demand paging for IOMMU is only supported for PCIe via PRI
+ * (Page Request Interface) not for HIDMA. All other hardware instances
+ * including HIDMA work on pinned DMA addresses.
+ *
+ * HIDMA is not aware of IOMMU presence since it follows the DMA API. All
+ * IOMMU latency will be built into the data movement time. By the time
+ * interrupt happens, IOMMU lookups + data movement has already taken place.
+ *
+ * While the first read in a typical PCI endpoint ISR flushes all outstanding
+ * requests traditionally to the destination, this concept does not apply
+ * here for this HW.
+ */
+static void hidma_ll_int_handler_internal(struct hidma_lldev *lldev)
+{
+	u32 status;
+	u32 enable;
+	u32 cause;
+
+	/*
+	 * Fine tuned for this HW...
+	 *
+	 * This ISR has been designed for this particular hardware. Relaxed
+	 * read and write accessors are used for performance reasons due to
+	 * interrupt delivery guarantees. Do not copy this code blindly and
+	 * expect that to work.
+	 */
+	status = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
+	enable = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
+	cause = status & enable;
+
+	while (cause) {
+		if ((cause & BIT(HIDMA_IRQ_TR_CH_INVALID_TRE_BIT_POS)) ||
+		    (cause & BIT(HIDMA_IRQ_TR_CH_TRE_RD_RSP_ER_BIT_POS)) ||
+		    (cause & BIT(HIDMA_IRQ_EV_CH_WR_RESP_BIT_POS)) ||
+		    (cause & BIT(HIDMA_IRQ_TR_CH_DATA_RD_ER_BIT_POS)) ||
+		    (cause & BIT(HIDMA_IRQ_TR_CH_DATA_WR_ER_BIT_POS))) {
+			u8 err_code = HIDMA_EVRE_STATUS_ERROR;
+			u8 err_info = 0xFF;
+
+			/* Clear out pending interrupts */
+			writel(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+
+			dev_err(lldev->dev, "error 0x%x, resetting...\n",
+				cause);
+
+			hidma_cleanup_pending_tre(lldev, err_info, err_code);
+
+			/* reset the channel for recovery */
+			if (hidma_ll_setup(lldev)) {
+				dev_err(lldev->dev,
+					"channel reinitialize failed after error\n");
+				return;
+			}
+			hidma_ll_enable_irq(lldev, ENABLE_IRQS);
+			return;
+		}
+
+		/*
+		 * Try to consume as many EVREs as possible.
+		 */
+		hidma_handle_tre_completion(lldev);
+
+		/* We consumed TREs or there are pending TREs or EVREs. */
+		writel_relaxed(cause, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+
+		/*
+		 * Another interrupt might have arrived while we are
+		 * processing this one. Read the new cause.
+		 */
+		status = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
+		enable = readl_relaxed(lldev->evca + HIDMA_EVCA_IRQ_EN_REG);
+		cause = status & enable;
+	}
+}
+
+static int hidma_ll_enable(struct hidma_lldev *lldev)
+{
+	u32 val;
+	int ret;
+
+	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_ENABLE << 16;
+	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+
+	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
+				 (HIDMA_CH_STATE(val) == HIDMA_CH_ENABLED) ||
+				 (HIDMA_CH_STATE(val) == HIDMA_CH_RUNNING),
+				 1000, 10000);
+	if (ret) {
+		dev_err(lldev->dev, "event channel did not get enabled\n");
+		return ret;
+	}
+
+	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_ENABLE << 16;
+	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+
+	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
+				 (HIDMA_CH_STATE(val) == HIDMA_CH_ENABLED) ||
+				 (HIDMA_CH_STATE(val) == HIDMA_CH_RUNNING),
+				 1000, 10000);
+	if (ret) {
+		dev_err(lldev->dev, "transfer channel did not get enabled\n");
+		return ret;
+	}
+
+	lldev->trch_state = HIDMA_CH_ENABLED;
+	lldev->evch_state = HIDMA_CH_ENABLED;
+
+	return 0;
+}
+
+int hidma_ll_resume(struct hidma_lldev *lldev)
+{
+	return hidma_ll_enable(lldev);
+}
+
+static void hidma_ll_hw_start(struct hidma_lldev *lldev)
+{
+	unsigned long irqflags;
+
+	spin_lock_irqsave(&lldev->lock, irqflags);
+	writel(lldev->tre_write_offset, lldev->trca + HIDMA_TRCA_DOORBELL_REG);
+	spin_unlock_irqrestore(&lldev->lock, irqflags);
+}
+
+bool hidma_ll_isenabled(struct hidma_lldev *lldev)
+{
+	u32 val;
+
+	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+	lldev->trch_state = HIDMA_CH_STATE(val);
+	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+	lldev->evch_state = HIDMA_CH_STATE(val);
+
+	/* both channels have to be enabled before calling this function */
+	if (((lldev->trch_state == HIDMA_CH_ENABLED) ||
+	     (lldev->trch_state == HIDMA_CH_RUNNING)) &&
+	    ((lldev->evch_state == HIDMA_CH_ENABLED) ||
+	     (lldev->evch_state == HIDMA_CH_RUNNING)))
+		return true;
+
+	return false;
+}
+
+void hidma_ll_queue_request(struct hidma_lldev *lldev, u32 tre_ch)
+{
+	struct hidma_tre *tre;
+	unsigned long flags;
+
+	tre = &lldev->trepool[tre_ch];
+
+	/* copy the TRE into its location in the TRE ring */
+	spin_lock_irqsave(&lldev->lock, flags);
+	tre->tre_index = lldev->tre_write_offset / HIDMA_TRE_SIZE;
+	lldev->pending_tre_list[tre->tre_index] = tre;
+	memcpy(lldev->tre_ring + lldev->tre_write_offset,
+	       &tre->tre_local[0], HIDMA_TRE_SIZE);
+	lldev->tx_status_list[tre->idx].err_code = 0;
+	lldev->tx_status_list[tre->idx].err_info = 0;
+	tre->queued = 1;
+	lldev->pending_tre_count++;
+	lldev->tre_write_offset = (lldev->tre_write_offset + HIDMA_TRE_SIZE)
+					% lldev->tre_ring_size;
+	spin_unlock_irqrestore(&lldev->lock, flags);
+}
+
+void hidma_ll_start(struct hidma_lldev *lldev)
+{
+	hidma_ll_hw_start(lldev);
+}
+
+/*
+ * Note that even though we stop this channel
+ * if there is a pending transaction in flight
+ * it will complete and follow the callback.
+ * This request will prevent further requests
+ * to be made.
+ */
+int hidma_ll_pause(struct hidma_lldev *lldev)
+{
+	u32 val;
+	int ret;
+
+	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+	lldev->evch_state = HIDMA_CH_STATE(val);
+	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+	lldev->trch_state = HIDMA_CH_STATE(val);
+
+	/* already suspended by this OS */
+	if ((lldev->trch_state == HIDMA_CH_SUSPENDED) ||
+	    (lldev->evch_state == HIDMA_CH_SUSPENDED))
+		return 0;
+
+	/* already stopped by the manager */
+	if ((lldev->trch_state == HIDMA_CH_STOPPED) ||
+	    (lldev->evch_state == HIDMA_CH_STOPPED))
+		return 0;
+
+	val = readl(lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_SUSPEND << 16;
+	writel(val, lldev->trca + HIDMA_TRCA_CTRLSTS_REG);
+
+	/*
+	 * Start the wait right after the suspend is confirmed.
+	 * Do a polled read up to 1ms and 10ms maximum.
+	 */
+	ret = readl_poll_timeout(lldev->trca + HIDMA_TRCA_CTRLSTS_REG, val,
+				 HIDMA_CH_STATE(val) == HIDMA_CH_SUSPENDED,
+				 1000, 10000);
+	if (ret)
+		return ret;
+
+	val = readl(lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+	val &= ~(HIDMA_CH_CONTROL_MASK << 16);
+	val |= HIDMA_CH_SUSPEND << 16;
+	writel(val, lldev->evca + HIDMA_EVCA_CTRLSTS_REG);
+
+	/*
+	 * Start the wait right after the suspend is confirmed
+	 * Delay up to 10ms after reset to allow DMA logic to quiesce.
+	 */
+	ret = readl_poll_timeout(lldev->evca + HIDMA_EVCA_CTRLSTS_REG, val,
+				 HIDMA_CH_STATE(val) == HIDMA_CH_SUSPENDED,
+				 1000, 10000);
+	if (ret)
+		return ret;
+
+	lldev->trch_state = HIDMA_CH_SUSPENDED;
+	lldev->evch_state = HIDMA_CH_SUSPENDED;
+	return 0;
+}
+
+void hidma_ll_set_transfer_params(struct hidma_lldev *lldev, u32 tre_ch,
+				  dma_addr_t src, dma_addr_t dest, u32 len,
+				  u32 flags)
+{
+	struct hidma_tre *tre;
+	u32 *tre_local;
+
+	if (tre_ch >= lldev->nr_tres) {
+		dev_err(lldev->dev,
+			"invalid TRE number in transfer params:%d", tre_ch);
+		return;
+	}
+
+	tre = &lldev->trepool[tre_ch];
+	if (atomic_read(&tre->allocated) != true) {
+		dev_err(lldev->dev,
+			"trying to set params on an unused TRE:%d", tre_ch);
+		return;
+	}
+
+	tre_local = &tre->tre_local[0];
+	tre_local[HIDMA_TRE_LEN_IDX] = len;
+	tre_local[HIDMA_TRE_SRC_LOW_IDX] = lower_32_bits(src);
+	tre_local[HIDMA_TRE_SRC_HI_IDX] = upper_32_bits(src);
+	tre_local[HIDMA_TRE_DEST_LOW_IDX] = lower_32_bits(dest);
+	tre_local[HIDMA_TRE_DEST_HI_IDX] = upper_32_bits(dest);
+	tre->int_flags = flags;
+}
+
+/*
+ * Called during initialization and after an error condition
+ * to restore hardware state.
+ */
+int hidma_ll_setup(struct hidma_lldev *lldev)
+{
+	int rc;
+	u64 addr;
+	u32 val;
+	u32 nr_tres = lldev->nr_tres;
+
+	lldev->pending_tre_count = 0;
+	lldev->tre_processed_off = 0;
+	lldev->evre_processed_off = 0;
+	lldev->tre_write_offset = 0;
+
+	/* disable interrupts */
+	hidma_ll_enable_irq(lldev, 0);
+
+	/* clear all pending interrupts */
+	val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
+	writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+
+	rc = hidma_ll_reset(lldev);
+	if (rc)
+		return rc;
+
+	/*
+	 * Clear all pending interrupts again.
+	 * Otherwise, we observe reset complete interrupts.
+	 */
+	val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
+	writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+
+	/* disable interrupts again after reset */
+	hidma_ll_enable_irq(lldev, 0);
+
+	addr = lldev->tre_ring_handle;
+	writel(lower_32_bits(addr), lldev->trca + HIDMA_TRCA_RING_LOW_REG);
+	writel(upper_32_bits(addr), lldev->trca + HIDMA_TRCA_RING_HIGH_REG);
+	writel(lldev->tre_ring_size, lldev->trca + HIDMA_TRCA_RING_LEN_REG);
+
+	addr = lldev->evre_ring_handle;
+	writel(lower_32_bits(addr), lldev->evca + HIDMA_EVCA_RING_LOW_REG);
+	writel(upper_32_bits(addr), lldev->evca + HIDMA_EVCA_RING_HIGH_REG);
+	writel(HIDMA_EVRE_SIZE * nr_tres,
+	       lldev->evca + HIDMA_EVCA_RING_LEN_REG);
+
+	/* support IRQ only for now */
+	val = readl(lldev->evca + HIDMA_EVCA_INTCTRL_REG);
+	val &= ~0xF;
+	val |= 0x1;
+	writel(val, lldev->evca + HIDMA_EVCA_INTCTRL_REG);
+
+	/* clear all pending interrupts and enable them */
+	writel(ENABLE_IRQS, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+	hidma_ll_enable_irq(lldev, ENABLE_IRQS);
+
+	rc = hidma_ll_enable(lldev);
+	if (rc)
+		return rc;
+
+	return rc;
+}
+
+struct hidma_lldev *hidma_ll_init(struct device *dev, u32 nr_tres,
+				  void __iomem *trca, void __iomem *evca,
+				  u8 chidx)
+{
+	u32 required_bytes;
+	struct hidma_lldev *lldev;
+	int rc;
+
+	if (!trca || !evca || !dev || !nr_tres)
+		return NULL;
+
+	/* need at least four TREs */
+	if (nr_tres < 4)
+		return NULL;
+
+	/* need an extra space */
+	nr_tres += 1;
+
+	lldev = devm_kzalloc(dev, sizeof(struct hidma_lldev), GFP_KERNEL);
+	if (!lldev)
+		return NULL;
+
+	lldev->evca = evca;
+	lldev->trca = trca;
+	lldev->dev = dev;
+	lldev->trepool = devm_kcalloc(lldev->dev, nr_tres,
+				      sizeof(struct hidma_tre), GFP_KERNEL);
+	if (!lldev->trepool)
+		return NULL;
+
+	required_bytes = sizeof(lldev->pending_tre_list[0]);
+	lldev->pending_tre_list = devm_kcalloc(dev, nr_tres, required_bytes,
+					       GFP_KERNEL);
+	if (!lldev->pending_tre_list)
+		return NULL;
+
+	lldev->tx_status_list = devm_kcalloc(dev, nr_tres,
+					     sizeof(lldev->tx_status_list[0]),
+					     GFP_KERNEL);
+	if (!lldev->tx_status_list)
+		return NULL;
+
+	lldev->tre_ring = dmam_alloc_coherent(dev,
+					      (HIDMA_TRE_SIZE + 1) * nr_tres,
+					      &lldev->tre_ring_handle,
+					      GFP_KERNEL);
+	if (!lldev->tre_ring)
+		return NULL;
+
+	memset(lldev->tre_ring, 0, (HIDMA_TRE_SIZE + 1) * nr_tres);
+	lldev->tre_ring_size = HIDMA_TRE_SIZE * nr_tres;
+	lldev->nr_tres = nr_tres;
+
+	/* the TRE ring has to be TRE_SIZE aligned */
+	if (!IS_ALIGNED(lldev->tre_ring_handle, HIDMA_TRE_SIZE)) {
+		u8 tre_ring_shift;
+
+		tre_ring_shift = lldev->tre_ring_handle % HIDMA_TRE_SIZE;
+		tre_ring_shift = HIDMA_TRE_SIZE - tre_ring_shift;
+		lldev->tre_ring_handle += tre_ring_shift;
+		lldev->tre_ring += tre_ring_shift;
+	}
+
+	lldev->evre_ring = dmam_alloc_coherent(dev,
+					       (HIDMA_EVRE_SIZE + 1) * nr_tres,
+					       &lldev->evre_ring_handle,
+					       GFP_KERNEL);
+	if (!lldev->evre_ring)
+		return NULL;
+
+	memset(lldev->evre_ring, 0, (HIDMA_EVRE_SIZE + 1) * nr_tres);
+	lldev->evre_ring_size = HIDMA_EVRE_SIZE * nr_tres;
+
+	/* the EVRE ring has to be EVRE_SIZE aligned */
+	if (!IS_ALIGNED(lldev->evre_ring_handle, HIDMA_EVRE_SIZE)) {
+		u8 evre_ring_shift;
+
+		evre_ring_shift = lldev->evre_ring_handle % HIDMA_EVRE_SIZE;
+		evre_ring_shift = HIDMA_EVRE_SIZE - evre_ring_shift;
+		lldev->evre_ring_handle += evre_ring_shift;
+		lldev->evre_ring += evre_ring_shift;
+	}
+	lldev->nr_tres = nr_tres;
+	lldev->chidx = chidx;
+
+	rc = kfifo_alloc(&lldev->handoff_fifo,
+			 nr_tres * sizeof(struct hidma_tre *), GFP_KERNEL);
+	if (rc)
+		return NULL;
+
+	rc = hidma_ll_setup(lldev);
+	if (rc)
+		return NULL;
+
+	spin_lock_init(&lldev->lock);
+	tasklet_init(&lldev->task, hidma_ll_tre_complete, (unsigned long)lldev);
+	lldev->initialized = 1;
+	hidma_ll_enable_irq(lldev, ENABLE_IRQS);
+	return lldev;
+}
+
+int hidma_ll_uninit(struct hidma_lldev *lldev)
+{
+	int rc = 0;
+	u32 val;
+
+	if (!lldev)
+		return -ENODEV;
+
+	if (lldev->initialized) {
+		u32 required_bytes;
+
+		lldev->initialized = 0;
+
+		required_bytes = sizeof(struct hidma_tre) * lldev->nr_tres;
+		tasklet_kill(&lldev->task);
+		memset(lldev->trepool, 0, required_bytes);
+		lldev->trepool = NULL;
+		lldev->pending_tre_count = 0;
+		lldev->tre_write_offset = 0;
+
+		rc = hidma_ll_reset(lldev);
+
+		/*
+		 * Clear all pending interrupts again.
+		 * Otherwise, we observe reset complete interrupts.
+		 */
+		val = readl(lldev->evca + HIDMA_EVCA_IRQ_STAT_REG);
+		writel(val, lldev->evca + HIDMA_EVCA_IRQ_CLR_REG);
+		hidma_ll_enable_irq(lldev, 0);
+	}
+	return rc;
+}
+
+irqreturn_t hidma_ll_inthandler(int chirq, void *arg)
+{
+	struct hidma_lldev *lldev = arg;
+
+	hidma_ll_int_handler_internal(lldev);
+	return IRQ_HANDLED;
+}
+
+enum dma_status hidma_ll_status(struct hidma_lldev *lldev, u32 tre_ch)
+{
+	enum dma_status ret = DMA_ERROR;
+	unsigned long flags;
+	u8 err_code;
+
+	spin_lock_irqsave(&lldev->lock, flags);
+	err_code = lldev->tx_status_list[tre_ch].err_code;
+
+	if (err_code & HIDMA_EVRE_STATUS_COMPLETE)
+		ret = DMA_COMPLETE;
+	else if (err_code & HIDMA_EVRE_STATUS_ERROR)
+		ret = DMA_ERROR;
+	else
+		ret = DMA_IN_PROGRESS;
+	spin_unlock_irqrestore(&lldev->lock, flags);
+
+	return ret;
+}
