dmaengine: qcom: Add ADM driver

Add the DMA engine driver for the QCOM Application Data Mover (ADM) DMA
controller found in the MSM8x60 and IPQ/APQ8064 platforms.

The ADM supports both memory to memory transactions and memory
to/from peripheral device transactions. The controller also provides
flow control capabilities for transactions to/from peripheral devices.

The initial release of this driver supports slave transfers to/from
peripherals and also incorporates CRCI (client rate control interface)
flow control.

The hardware only supports a 32 bit physical address, so specifying
!PHYS_ADDR_T_64BIT gives maximum COMPILE_TEST coverage without having to
spend effort on kludging things in the code that will never actually be
needed on real hardware.

Signed-off-by: Andy Gross <[e-mail]>
Signed-off-by: Thomas Pedersen <[e-mail]>
Signed-off-by: Jonathan McDowell <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/qcom/Kconfig

···
 # SPDX-License-Identifier: GPL-2.0-only
+config QCOM_ADM
+	tristate "Qualcomm ADM support"
+	depends on (ARCH_QCOM || COMPILE_TEST) && !PHYS_ADDR_T_64BIT
+	select DMA_ENGINE
+	select DMA_VIRTUAL_CHANNELS
+	help
+	  Enable support for the Qualcomm Application Data Mover (ADM) DMA
+	  controller, as present on MSM8x60, APQ8064, and IPQ8064 devices.
+	  This controller provides DMA capabilities for both general purpose
+	  and on-chip peripheral devices.
+
 config QCOM_BAM_DMA
 	tristate "QCOM BAM DMA support"
 	depends on ARCH_QCOM || (COMPILE_TEST && OF && ARM)

drivers/dma/qcom/Makefile

···
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_QCOM_ADM) += qcom_adm.o
 obj-$(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

drivers/dma/qcom/qcom_adm.c

···
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2013-2015, The Linux Foundation. All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/of_dma.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+
+#include "../dmaengine.h"
+#include "../virt-dma.h"
+
+/* ADM registers - calculated from channel number and security domain */
+#define ADM_CHAN_MULTI			0x4
+#define ADM_CI_MULTI			0x4
+#define ADM_CRCI_MULTI			0x4
+#define ADM_EE_MULTI			0x800
+#define ADM_CHAN_OFFS(chan)		(ADM_CHAN_MULTI * (chan))
+#define ADM_EE_OFFS(ee)			(ADM_EE_MULTI * (ee))
+#define ADM_CHAN_EE_OFFS(chan, ee)	(ADM_CHAN_OFFS(chan) + ADM_EE_OFFS(ee))
+#define ADM_CHAN_OFFS(chan)		(ADM_CHAN_MULTI * (chan))
+#define ADM_CI_OFFS(ci)			(ADM_CHAN_OFF(ci))
+#define ADM_CH_CMD_PTR(chan, ee)	(ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_RSLT(chan, ee)		(0x40 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_FLUSH_STATE0(chan, ee)	(0x80 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_STATUS_SD(chan, ee)	(0x200 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_CH_CONF(chan)		(0x240 + ADM_CHAN_OFFS(chan))
+#define ADM_CH_RSLT_CONF(chan, ee)	(0x300 + ADM_CHAN_EE_OFFS(chan, ee))
+#define ADM_SEC_DOMAIN_IRQ_STATUS(ee)	(0x380 + ADM_EE_OFFS(ee))
+#define ADM_CI_CONF(ci)			(0x390 + (ci) * ADM_CI_MULTI)
+#define ADM_GP_CTL			0x3d8
+#define ADM_CRCI_CTL(crci, ee)		(0x400 + (crci) * ADM_CRCI_MULTI + \
+						ADM_EE_OFFS(ee))
+
+/* channel status */
+#define ADM_CH_STATUS_VALID		BIT(1)
+
+/* channel result */
+#define ADM_CH_RSLT_VALID		BIT(31)
+#define ADM_CH_RSLT_ERR			BIT(3)
+#define ADM_CH_RSLT_FLUSH		BIT(2)
+#define ADM_CH_RSLT_TPD			BIT(1)
+
+/* channel conf */
+#define ADM_CH_CONF_SHADOW_EN		BIT(12)
+#define ADM_CH_CONF_MPU_DISABLE		BIT(11)
+#define ADM_CH_CONF_PERM_MPU_CONF	BIT(9)
+#define ADM_CH_CONF_FORCE_RSLT_EN	BIT(7)
+#define ADM_CH_CONF_SEC_DOMAIN(ee)	((((ee) & 0x3) << 4) | (((ee) & 0x4) << 11))
+
+/* channel result conf */
+#define ADM_CH_RSLT_CONF_FLUSH_EN	BIT(1)
+#define ADM_CH_RSLT_CONF_IRQ_EN		BIT(0)
+
+/* CRCI CTL */
+#define ADM_CRCI_CTL_MUX_SEL		BIT(18)
+#define ADM_CRCI_CTL_RST		BIT(17)
+
+/* CI configuration */
+#define ADM_CI_RANGE_END(x)		((x) << 24)
+#define ADM_CI_RANGE_START(x)		((x) << 16)
+#define ADM_CI_BURST_4_WORDS		BIT(2)
+#define ADM_CI_BURST_8_WORDS		BIT(3)
+
+/* GP CTL */
+#define ADM_GP_CTL_LP_EN		BIT(12)
+#define ADM_GP_CTL_LP_CNT(x)		((x) << 8)
+
+/* Command pointer list entry */
+#define ADM_CPLE_LP			BIT(31)
+#define ADM_CPLE_CMD_PTR_LIST		BIT(29)
+
+/* Command list entry */
+#define ADM_CMD_LC			BIT(31)
+#define ADM_CMD_DST_CRCI(n)		(((n) & 0xf) << 7)
+#define ADM_CMD_SRC_CRCI(n)		(((n) & 0xf) << 3)
+
+#define ADM_CMD_TYPE_SINGLE		0x0
+#define ADM_CMD_TYPE_BOX		0x3
+
+#define ADM_CRCI_MUX_SEL		BIT(4)
+#define ADM_DESC_ALIGN			8
+#define ADM_MAX_XFER			(SZ_64K - 1)
+#define ADM_MAX_ROWS			(SZ_64K - 1)
+#define ADM_MAX_CHANNELS		16
+
+struct adm_desc_hw_box {
+	u32 cmd;
+	u32 src_addr;
+	u32 dst_addr;
+	u32 row_len;
+	u32 num_rows;
+	u32 row_offset;
+};
+
+struct adm_desc_hw_single {
+	u32 cmd;
+	u32 src_addr;
+	u32 dst_addr;
+	u32 len;
+};
+
+struct adm_async_desc {
+	struct virt_dma_desc vd;
+	struct adm_device *adev;
+
+	size_t length;
+	enum dma_transfer_direction dir;
+	dma_addr_t dma_addr;
+	size_t dma_len;
+
+	void *cpl;
+	dma_addr_t cp_addr;
+	u32 crci;
+	u32 mux;
+	u32 blk_size;
+};
+
+struct adm_chan {
+	struct virt_dma_chan vc;
+	struct adm_device *adev;
+
+	/* parsed from DT */
+	u32 id;			/* channel id */
+
+	struct adm_async_desc *curr_txd;
+	struct dma_slave_config slave;
+	struct list_head node;
+
+	int error;
+	int initialized;
+};
+
+static inline struct adm_chan *to_adm_chan(struct dma_chan *common)
+{
+	return container_of(common, struct adm_chan, vc.chan);
+}
+
+struct adm_device {
+	void __iomem *regs;
+	struct device *dev;
+	struct dma_device common;
+	struct device_dma_parameters dma_parms;
+	struct adm_chan *channels;
+
+	u32 ee;
+
+	struct clk *core_clk;
+	struct clk *iface_clk;
+
+	struct reset_control *clk_reset;
+	struct reset_control *c0_reset;
+	struct reset_control *c1_reset;
+	struct reset_control *c2_reset;
+	int irq;
+};
+
+/**
+ * adm_free_chan - Frees dma resources associated with the specific channel
+ *
+ * Free all allocated descriptors associated with this channel
+ *
+ */
+static void adm_free_chan(struct dma_chan *chan)
+{
+	/* free all queued descriptors */
+	vchan_free_chan_resources(to_virt_chan(chan));
+}
+
+/**
+ * adm_get_blksize - Get block size from burst value
+ *
+ */
+static int adm_get_blksize(unsigned int burst)
+{
+	int ret;
+
+	switch (burst) {
+	case 16:
+	case 32:
+	case 64:
+	case 128:
+		ret = ffs(burst >> 4) - 1;
+		break;
+	case 192:
+		ret = 4;
+		break;
+	case 256:
+		ret = 5;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+/**
+ * adm_process_fc_descriptors - Process descriptors for flow controlled xfers
+ *
+ * @achan: ADM channel
+ * @desc: Descriptor memory pointer
+ * @sg: Scatterlist entry
+ * @crci: CRCI value
+ * @burst: Burst size of transaction
+ * @direction: DMA transfer direction
+ */
+static void *adm_process_fc_descriptors(struct adm_chan *achan, void *desc,
+					struct scatterlist *sg, u32 crci,
+					u32 burst,
+					enum dma_transfer_direction direction)
+{
+	struct adm_desc_hw_box *box_desc = NULL;
+	struct adm_desc_hw_single *single_desc;
+	u32 remainder = sg_dma_len(sg);
+	u32 rows, row_offset, crci_cmd;
+	u32 mem_addr = sg_dma_address(sg);
+	u32 *incr_addr = &mem_addr;
+	u32 *src, *dst;
+
+	if (direction == DMA_DEV_TO_MEM) {
+		crci_cmd = ADM_CMD_SRC_CRCI(crci);
+		row_offset = burst;
+		src = &achan->slave.src_addr;
+		dst = &mem_addr;
+	} else {
+		crci_cmd = ADM_CMD_DST_CRCI(crci);
+		row_offset = burst << 16;
+		src = &mem_addr;
+		dst = &achan->slave.dst_addr;
+	}
+
+	while (remainder >= burst) {
+		box_desc = desc;
+		box_desc->cmd = ADM_CMD_TYPE_BOX | crci_cmd;
+		box_desc->row_offset = row_offset;
+		box_desc->src_addr = *src;
+		box_desc->dst_addr = *dst;
+
+		rows = remainder / burst;
+		rows = min_t(u32, rows, ADM_MAX_ROWS);
+		box_desc->num_rows = rows << 16 | rows;
+		box_desc->row_len = burst << 16 | burst;
+
+		*incr_addr += burst * rows;
+		remainder -= burst * rows;
+		desc += sizeof(*box_desc);
+	}
+
+	/* if leftover bytes, do one single descriptor */
+	if (remainder) {
+		single_desc = desc;
+		single_desc->cmd = ADM_CMD_TYPE_SINGLE | crci_cmd;
+		single_desc->len = remainder;
+		single_desc->src_addr = *src;
+		single_desc->dst_addr = *dst;
+		desc += sizeof(*single_desc);
+
+		if (sg_is_last(sg))
+			single_desc->cmd |= ADM_CMD_LC;
+	} else {
+		if (box_desc && sg_is_last(sg))
+			box_desc->cmd |= ADM_CMD_LC;
+	}
+
+	return desc;
+}
+
+/**
+ * adm_process_non_fc_descriptors - Process descriptors for non-fc xfers
+ *
+ * @achan: ADM channel
+ * @desc: Descriptor memory pointer
+ * @sg: Scatterlist entry
+ * @direction: DMA transfer direction
+ */
+static void *adm_process_non_fc_descriptors(struct adm_chan *achan, void *desc,
+					    struct scatterlist *sg,
+					    enum dma_transfer_direction direction)
+{
+	struct adm_desc_hw_single *single_desc;
+	u32 remainder = sg_dma_len(sg);
+	u32 mem_addr = sg_dma_address(sg);
+	u32 *incr_addr = &mem_addr;
+	u32 *src, *dst;
+
+	if (direction == DMA_DEV_TO_MEM) {
+		src = &achan->slave.src_addr;
+		dst = &mem_addr;
+	} else {
+		src = &mem_addr;
+		dst = &achan->slave.dst_addr;
+	}
+
+	do {
+		single_desc = desc;
+		single_desc->cmd = ADM_CMD_TYPE_SINGLE;
+		single_desc->src_addr = *src;
+		single_desc->dst_addr = *dst;
+		single_desc->len = (remainder > ADM_MAX_XFER) ?
+				ADM_MAX_XFER : remainder;
+
+		remainder -= single_desc->len;
+		*incr_addr += single_desc->len;
+		desc += sizeof(*single_desc);
+	} while (remainder);
+
+	/* set last command if this is the end of the whole transaction */
+	if (sg_is_last(sg))
+		single_desc->cmd |= ADM_CMD_LC;
+
+	return desc;
+}
+
+/**
+ * adm_prep_slave_sg - Prep slave sg transaction
+ *
+ * @chan: dma channel
+ * @sgl: scatter gather list
+ * @sg_len: length of sg
+ * @direction: DMA transfer direction
+ * @flags: DMA flags
+ * @context: transfer context (unused)
+ */
+static struct dma_async_tx_descriptor *adm_prep_slave_sg(struct dma_chan *chan,
+							 struct scatterlist *sgl,
+							 unsigned int sg_len,
+							 enum dma_transfer_direction direction,
+							 unsigned long flags,
+							 void *context)
+{
+	struct adm_chan *achan = to_adm_chan(chan);
+	struct adm_device *adev = achan->adev;
+	struct adm_async_desc *async_desc;
+	struct scatterlist *sg;
+	dma_addr_t cple_addr;
+	u32 i, burst;
+	u32 single_count = 0, box_count = 0, crci = 0;
+	void *desc;
+	u32 *cple;
+	int blk_size = 0;
+
+	if (!is_slave_direction(direction)) {
+		dev_err(adev->dev, "invalid dma direction\n");
+		return NULL;
+	}
+
+	/*
+	 * get burst value from slave configuration
+	 */
+	burst = (direction == DMA_MEM_TO_DEV) ?
+		achan->slave.dst_maxburst :
+		achan->slave.src_maxburst;
+
+	/* if using flow control, validate burst and crci values */
+	if (achan->slave.device_fc) {
+		blk_size = adm_get_blksize(burst);
+		if (blk_size < 0) {
+			dev_err(adev->dev, "invalid burst value: %d\n",
+				burst);
+			return ERR_PTR(-EINVAL);
+		}
+
+		crci = achan->slave.slave_id & 0xf;
+		if (!crci || achan->slave.slave_id > 0x1f) {
+			dev_err(adev->dev, "invalid crci value\n");
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* iterate through sgs and compute allocation size of structures */
+	for_each_sg(sgl, sg, sg_len, i) {
+		if (achan->slave.device_fc) {
+			box_count += DIV_ROUND_UP(sg_dma_len(sg) / burst,
+						  ADM_MAX_ROWS);
+			if (sg_dma_len(sg) % burst)
+				single_count++;
+		} else {
+			single_count += DIV_ROUND_UP(sg_dma_len(sg),
+						     ADM_MAX_XFER);
+		}
+	}
+
+	async_desc = kzalloc(sizeof(*async_desc), GFP_NOWAIT);
+	if (!async_desc)
+		return ERR_PTR(-ENOMEM);
+
+	if (crci)
+		async_desc->mux = achan->slave.slave_id & ADM_CRCI_MUX_SEL ?
+					ADM_CRCI_CTL_MUX_SEL : 0;
+	async_desc->crci = crci;
+	async_desc->blk_size = blk_size;
+	async_desc->dma_len = single_count * sizeof(struct adm_desc_hw_single) +
+				box_count * sizeof(struct adm_desc_hw_box) +
+				sizeof(*cple) + 2 * ADM_DESC_ALIGN;
+
+	async_desc->cpl = kzalloc(async_desc->dma_len, GFP_NOWAIT);
+	if (!async_desc->cpl)
+		goto free;
+
+	async_desc->adev = adev;
+
+	/* both command list entry and descriptors must be 8 byte aligned */
+	cple = PTR_ALIGN(async_desc->cpl, ADM_DESC_ALIGN);
+	desc = PTR_ALIGN(cple + 1, ADM_DESC_ALIGN);
+
+	for_each_sg(sgl, sg, sg_len, i) {
+		async_desc->length += sg_dma_len(sg);
+
+		if (achan->slave.device_fc)
+			desc = adm_process_fc_descriptors(achan, desc, sg, crci,
+							  burst, direction);
+		else
+			desc = adm_process_non_fc_descriptors(achan, desc, sg,
+							      direction);
+	}
+
+	async_desc->dma_addr = dma_map_single(adev->dev, async_desc->cpl,
+					      async_desc->dma_len,
+					      DMA_TO_DEVICE);
+	if (dma_mapping_error(adev->dev, async_desc->dma_addr))
+		goto free;
+
+	cple_addr = async_desc->dma_addr + ((void *)cple - async_desc->cpl);
+
+	/* init cmd list */
+	dma_sync_single_for_cpu(adev->dev, cple_addr, sizeof(*cple),
+				DMA_TO_DEVICE);
+	*cple = ADM_CPLE_LP;
+	*cple |= (async_desc->dma_addr + ADM_DESC_ALIGN) >> 3;
+	dma_sync_single_for_device(adev->dev, cple_addr, sizeof(*cple),
+				   DMA_TO_DEVICE);
+
+	return vchan_tx_prep(&achan->vc, &async_desc->vd, flags);
+
+free:
+	kfree(async_desc);
+	return ERR_PTR(-ENOMEM);
+}
+
+/**
+ * adm_terminate_all - terminate all transactions on a channel
+ * @achan: adm dma channel
+ *
+ * Dequeues and frees all transactions, aborts current transaction
+ * No callbacks are done
+ *
+ */
+static int adm_terminate_all(struct dma_chan *chan)
+{
+	struct adm_chan *achan = to_adm_chan(chan);
+	struct adm_device *adev = achan->adev;
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&achan->vc.lock, flags);
+	vchan_get_all_descriptors(&achan->vc, &head);
+
+	/* send flush command to terminate current transaction */
+	writel_relaxed(0x0,
+		       adev->regs + ADM_CH_FLUSH_STATE0(achan->id, adev->ee));
+
+	spin_unlock_irqrestore(&achan->vc.lock, flags);
+
+	vchan_dma_desc_free_list(&achan->vc, &head);
+
+	return 0;
+}
+
+static int adm_slave_config(struct dma_chan *chan, struct dma_slave_config *cfg)
+{
+	struct adm_chan *achan = to_adm_chan(chan);
+	unsigned long flag;
+
+	spin_lock_irqsave(&achan->vc.lock, flag);
+	memcpy(&achan->slave, cfg, sizeof(struct dma_slave_config));
+	spin_unlock_irqrestore(&achan->vc.lock, flag);
+
+	return 0;
+}
+
+/**
+ * adm_start_dma - start next transaction
+ * @achan - ADM dma channel
+ */
+static void adm_start_dma(struct adm_chan *achan)
+{
+	struct virt_dma_desc *vd = vchan_next_desc(&achan->vc);
+	struct adm_device *adev = achan->adev;
+	struct adm_async_desc *async_desc;
+
+	lockdep_assert_held(&achan->vc.lock);
+
+	if (!vd)
+		return;
+
+	list_del(&vd->node);
+
+	/* write next command list out to the CMD FIFO */
+	async_desc = container_of(vd, struct adm_async_desc, vd);
+	achan->curr_txd = async_desc;
+
+	/* reset channel error */
+	achan->error = 0;
+
+	if (!achan->initialized) {
+		/* enable interrupts */
+		writel(ADM_CH_CONF_SHADOW_EN |
+		       ADM_CH_CONF_PERM_MPU_CONF |
+		       ADM_CH_CONF_MPU_DISABLE |
+		       ADM_CH_CONF_SEC_DOMAIN(adev->ee),
+		       adev->regs + ADM_CH_CONF(achan->id));
+
+		writel(ADM_CH_RSLT_CONF_IRQ_EN | ADM_CH_RSLT_CONF_FLUSH_EN,
+		       adev->regs + ADM_CH_RSLT_CONF(achan->id, adev->ee));
+
+		achan->initialized = 1;
+	}
+
+	/* set the crci block size if this transaction requires CRCI */
+	if (async_desc->crci) {
+		writel(async_desc->mux | async_desc->blk_size,
+		       adev->regs + ADM_CRCI_CTL(async_desc->crci, adev->ee));
+	}
+
+	/* make sure IRQ enable doesn't get reordered */
+	wmb();
+
+	/* write next command list out to the CMD FIFO */
+	writel(ALIGN(async_desc->dma_addr, ADM_DESC_ALIGN) >> 3,
+	       adev->regs + ADM_CH_CMD_PTR(achan->id, adev->ee));
+}
+
+/**
+ * adm_dma_irq - irq handler for ADM controller
+ * @irq: IRQ of interrupt
+ * @data: callback data
+ *
+ * IRQ handler for the bam controller
+ */
+static irqreturn_t adm_dma_irq(int irq, void *data)
+{
+	struct adm_device *adev = data;
+	u32 srcs, i;
+	struct adm_async_desc *async_desc;
+	unsigned long flags;
+
+	srcs = readl_relaxed(adev->regs +
+			ADM_SEC_DOMAIN_IRQ_STATUS(adev->ee));
+
+	for (i = 0; i < ADM_MAX_CHANNELS; i++) {
+		struct adm_chan *achan = &adev->channels[i];
+		u32 status, result;
+
+		if (srcs & BIT(i)) {
+			status = readl_relaxed(adev->regs +
+					       ADM_CH_STATUS_SD(i, adev->ee));
+
+			/* if no result present, skip */
+			if (!(status & ADM_CH_STATUS_VALID))
+				continue;
+
+			result = readl_relaxed(adev->regs +
+				ADM_CH_RSLT(i, adev->ee));
+
+			/* no valid results, skip */
+			if (!(result & ADM_CH_RSLT_VALID))
+				continue;
+
+			/* flag error if transaction was flushed or failed */
+			if (result & (ADM_CH_RSLT_ERR | ADM_CH_RSLT_FLUSH))
+				achan->error = 1;
+
+			spin_lock_irqsave(&achan->vc.lock, flags);
+			async_desc = achan->curr_txd;
+
+			achan->curr_txd = NULL;
+
+			if (async_desc) {
+				vchan_cookie_complete(&async_desc->vd);
+
+				/* kick off next DMA */
+				adm_start_dma(achan);
+			}
+
+			spin_unlock_irqrestore(&achan->vc.lock, flags);
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+/**
+ * adm_tx_status - returns status of transaction
+ * @chan: dma channel
+ * @cookie: transaction cookie
+ * @txstate: DMA transaction state
+ *
+ * Return status of dma transaction
+ */
+static enum dma_status adm_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
+				     struct dma_tx_state *txstate)
+{
+	struct adm_chan *achan = to_adm_chan(chan);
+	struct virt_dma_desc *vd;
+	enum dma_status ret;
+	unsigned long flags;
+	size_t residue = 0;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_COMPLETE || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&achan->vc.lock, flags);
+
+	vd = vchan_find_desc(&achan->vc, cookie);
+	if (vd)
+		residue = container_of(vd, struct adm_async_desc, vd)->length;
+
+	spin_unlock_irqrestore(&achan->vc.lock, flags);
+
+	/*
+	 * residue is either the full length if it is in the issued list, or 0
+	 * if it is in progress.  We have no reliable way of determining
+	 * anything inbetween
+	 */
+	dma_set_residue(txstate, residue);
+
+	if (achan->error)
+		return DMA_ERROR;
+
+	return ret;
+}
+
+/**
+ * adm_issue_pending - starts pending transactions
+ * @chan: dma channel
+ *
+ * Issues all pending transactions and starts DMA
+ */
+static void adm_issue_pending(struct dma_chan *chan)
+{
+	struct adm_chan *achan = to_adm_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&achan->vc.lock, flags);
+
+	if (vchan_issue_pending(&achan->vc) && !achan->curr_txd)
+		adm_start_dma(achan);
+	spin_unlock_irqrestore(&achan->vc.lock, flags);
+}
+
+/**
+ * adm_dma_free_desc - free descriptor memory
+ * @vd: virtual descriptor
+ *
+ */
+static void adm_dma_free_desc(struct virt_dma_desc *vd)
+{
+	struct adm_async_desc *async_desc = container_of(vd,
+			struct adm_async_desc, vd);
+
+	dma_unmap_single(async_desc->adev->dev, async_desc->dma_addr,
+			 async_desc->dma_len, DMA_TO_DEVICE);
+	kfree(async_desc->cpl);
+	kfree(async_desc);
+}
+
+static void adm_channel_init(struct adm_device *adev, struct adm_chan *achan,
+			     u32 index)
+{
+	achan->id = index;
+	achan->adev = adev;
+
+	vchan_init(&achan->vc, &adev->common);
+	achan->vc.desc_free = adm_dma_free_desc;
+}
+
+static int adm_dma_probe(struct platform_device *pdev)
+{
+	struct adm_device *adev;
+	int ret;
+	u32 i;
+
+	adev = devm_kzalloc(&pdev->dev, sizeof(*adev), GFP_KERNEL);
+	if (!adev)
+		return -ENOMEM;
+
+	adev->dev = &pdev->dev;
+
+	adev->regs = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(adev->regs))
+		return PTR_ERR(adev->regs);
+
+	adev->irq = platform_get_irq(pdev, 0);
+	if (adev->irq < 0)
+		return adev->irq;
+
+	ret = of_property_read_u32(pdev->dev.of_node, "qcom,ee", &adev->ee);
+	if (ret) {
+		dev_err(adev->dev, "Execution environment unspecified\n");
+		return ret;
+	}
+
+	adev->core_clk = devm_clk_get(adev->dev, "core");
+	if (IS_ERR(adev->core_clk))
+		return PTR_ERR(adev->core_clk);
+
+	adev->iface_clk = devm_clk_get(adev->dev, "iface");
+	if (IS_ERR(adev->iface_clk))
+		return PTR_ERR(adev->iface_clk);
+
+	adev->clk_reset = devm_reset_control_get_exclusive(&pdev->dev, "clk");
+	if (IS_ERR(adev->clk_reset)) {
+		dev_err(adev->dev, "failed to get ADM0 reset\n");
+		return PTR_ERR(adev->clk_reset);
+	}
+
+	adev->c0_reset = devm_reset_control_get_exclusive(&pdev->dev, "c0");
+	if (IS_ERR(adev->c0_reset)) {
+		dev_err(adev->dev, "failed to get ADM0 C0 reset\n");
+		return PTR_ERR(adev->c0_reset);
+	}
+
+	adev->c1_reset = devm_reset_control_get_exclusive(&pdev->dev, "c1");
+	if (IS_ERR(adev->c1_reset)) {
+		dev_err(adev->dev, "failed to get ADM0 C1 reset\n");
+		return PTR_ERR(adev->c1_reset);
+	}
+
+	adev->c2_reset = devm_reset_control_get_exclusive(&pdev->dev, "c2");
+	if (IS_ERR(adev->c2_reset)) {
+		dev_err(adev->dev, "failed to get ADM0 C2 reset\n");
+		return PTR_ERR(adev->c2_reset);
+	}
+
+	ret = clk_prepare_enable(adev->core_clk);
+	if (ret) {
+		dev_err(adev->dev, "failed to prepare/enable core clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(adev->iface_clk);
+	if (ret) {
+		dev_err(adev->dev, "failed to prepare/enable iface clock\n");
+		goto err_disable_core_clk;
+	}
+
+	reset_control_assert(adev->clk_reset);
+	reset_control_assert(adev->c0_reset);
+	reset_control_assert(adev->c1_reset);
+	reset_control_assert(adev->c2_reset);
+
+	udelay(2);
+
+	reset_control_deassert(adev->clk_reset);
+	reset_control_deassert(adev->c0_reset);
+	reset_control_deassert(adev->c1_reset);
+	reset_control_deassert(adev->c2_reset);
+
+	adev->channels = devm_kcalloc(adev->dev, ADM_MAX_CHANNELS,
+				      sizeof(*adev->channels), GFP_KERNEL);
+
+	if (!adev->channels) {
+		ret = -ENOMEM;
+		goto err_disable_clks;
+	}
+
+	/* allocate and initialize channels */
+	INIT_LIST_HEAD(&adev->common.channels);
+
+	for (i = 0; i < ADM_MAX_CHANNELS; i++)
+		adm_channel_init(adev, &adev->channels[i], i);
+
+	/* reset CRCIs */
+	for (i = 0; i < 16; i++)
+		writel(ADM_CRCI_CTL_RST, adev->regs +
+			ADM_CRCI_CTL(i, adev->ee));
+
+	/* configure client interfaces */
+	writel(ADM_CI_RANGE_START(0x40) | ADM_CI_RANGE_END(0xb0) |
+	       ADM_CI_BURST_8_WORDS, adev->regs + ADM_CI_CONF(0));
+	writel(ADM_CI_RANGE_START(0x2a) | ADM_CI_RANGE_END(0x2c) |
+	       ADM_CI_BURST_8_WORDS, adev->regs + ADM_CI_CONF(1));
+	writel(ADM_CI_RANGE_START(0x12) | ADM_CI_RANGE_END(0x28) |
+	       ADM_CI_BURST_8_WORDS, adev->regs + ADM_CI_CONF(2));
+	writel(ADM_GP_CTL_LP_EN | ADM_GP_CTL_LP_CNT(0xf),
+	       adev->regs + ADM_GP_CTL);
+
+	ret = devm_request_irq(adev->dev, adev->irq, adm_dma_irq,
+			       0, "adm_dma", adev);
+	if (ret)
+		goto err_disable_clks;
+
+	platform_set_drvdata(pdev, adev);
+
+	adev->common.dev = adev->dev;
+	adev->common.dev->dma_parms = &adev->dma_parms;
+
+	/* set capabilities */
+	dma_cap_zero(adev->common.cap_mask);
+	dma_cap_set(DMA_SLAVE, adev->common.cap_mask);
+	dma_cap_set(DMA_PRIVATE, adev->common.cap_mask);
+
+	/* initialize dmaengine apis */
+	adev->common.directions = BIT(DMA_DEV_TO_MEM | DMA_MEM_TO_DEV);
+	adev->common.residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
+	adev->common.src_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	adev->common.dst_addr_widths = DMA_SLAVE_BUSWIDTH_4_BYTES;
+	adev->common.device_free_chan_resources = adm_free_chan;
+	adev->common.device_prep_slave_sg = adm_prep_slave_sg;
+	adev->common.device_issue_pending = adm_issue_pending;
+	adev->common.device_tx_status = adm_tx_status;
+	adev->common.device_terminate_all = adm_terminate_all;
+	adev->common.device_config = adm_slave_config;
+
+	ret = dma_async_device_register(&adev->common);
+	if (ret) {
+		dev_err(adev->dev, "failed to register dma async device\n");
+		goto err_disable_clks;
+	}
+
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 of_dma_xlate_by_chan_id,
+					 &adev->common);
+	if (ret)
+		goto err_unregister_dma;
+
+	return 0;
+
+err_unregister_dma:
+	dma_async_device_unregister(&adev->common);
+err_disable_clks:
+	clk_disable_unprepare(adev->iface_clk);
+err_disable_core_clk:
+	clk_disable_unprepare(adev->core_clk);
+
+	return ret;
+}
+
+static int adm_dma_remove(struct platform_device *pdev)
+{
+	struct adm_device *adev = platform_get_drvdata(pdev);
+	struct adm_chan *achan;
+	u32 i;
+
+	of_dma_controller_free(pdev->dev.of_node);
+	dma_async_device_unregister(&adev->common);
+
+	for (i = 0; i < ADM_MAX_CHANNELS; i++) {
+		achan = &adev->channels[i];
+
+		/* mask IRQs for this channel/EE pair */
+		writel(0, adev->regs + ADM_CH_RSLT_CONF(achan->id, adev->ee));
+
+		tasklet_kill(&adev->channels[i].vc.task);
+		adm_terminate_all(&adev->channels[i].vc.chan);
+	}
+
+	devm_free_irq(adev->dev, adev->irq, adev);
+
+	clk_disable_unprepare(adev->core_clk);
+	clk_disable_unprepare(adev->iface_clk);
+
+	return 0;
+}
+
+static const struct of_device_id adm_of_match[] = {
+	{ .compatible = "qcom,adm", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, adm_of_match);
+
+static struct platform_driver adm_dma_driver = {
+	.probe = adm_dma_probe,
+	.remove = adm_dma_remove,
+	.driver = {
+		.name = "adm-dma-engine",
+		.of_match_table = adm_of_match,
+	},
+};
+
+module_platform_driver(adm_dma_driver);
+
+MODULE_AUTHOR("Andy Gross <[e-mail]>");
+MODULE_DESCRIPTION("QCOM ADM DMA engine driver");
+MODULE_LICENSE("GPL v2");