Initial import

1 files changed, 1103 insertions, 0 deletions

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
new file mode 100644
index 000000000..bf09db7ca
--- /dev/null
+++ b/drivers/dma/edma.c
@@ -0,0 +1,1103 @@
+/*
+ * TI EDMA DMA engine driver
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; 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/dma-mapping.h>
+#include <linux/edma.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/of.h>
+
+#include <linux/platform_data/edma.h>
+
+#include "dmaengine.h"
+#include "virt-dma.h"
+
+/*
+ * This will go away when the private EDMA API is folded
+ * into this driver and the platform device(s) are
+ * instantiated in the arch code. We can only get away
+ * with this simplification because DA8XX may not be built
+ * in the same kernel image with other DaVinci parts. This
+ * avoids having to sprinkle dmaengine driver platform devices
+ * and data throughout all the existing board files.
+ */
+#ifdef CONFIG_ARCH_DAVINCI_DA8XX
+#define EDMA_CTLRS	2
+#define EDMA_CHANS	32
+#else
+#define EDMA_CTLRS	1
+#define EDMA_CHANS	64
+#endif /* CONFIG_ARCH_DAVINCI_DA8XX */
+
+/*
+ * Max of 20 segments per channel to conserve PaRAM slots
+ * Also note that MAX_NR_SG should be atleast the no.of periods
+ * that are required for ASoC, otherwise DMA prep calls will
+ * fail. Today davinci-pcm is the only user of this driver and
+ * requires atleast 17 slots, so we setup the default to 20.
+ */
+#define MAX_NR_SG		20
+#define EDMA_MAX_SLOTS		MAX_NR_SG
+#define EDMA_DESCRIPTORS	16
+
+struct edma_pset {
+	u32				len;
+	dma_addr_t			addr;
+	struct edmacc_param		param;
+};
+
+struct edma_desc {
+	struct virt_dma_desc		vdesc;
+	struct list_head		node;
+	enum dma_transfer_direction	direction;
+	int				cyclic;
+	int				absync;
+	int				pset_nr;
+	struct edma_chan		*echan;
+	int				processed;
+
+	/*
+	 * The following 4 elements are used for residue accounting.
+	 *
+	 * - processed_stat: the number of SG elements we have traversed
+	 * so far to cover accounting. This is updated directly to processed
+	 * during edma_callback and is always <= processed, because processed
+	 * refers to the number of pending transfer (programmed to EDMA
+	 * controller), where as processed_stat tracks number of transfers
+	 * accounted for so far.
+	 *
+	 * - residue: The amount of bytes we have left to transfer for this desc
+	 *
+	 * - residue_stat: The residue in bytes of data we have covered
+	 * so far for accounting. This is updated directly to residue
+	 * during callbacks to keep it current.
+	 *
+	 * - sg_len: Tracks the length of the current intermediate transfer,
+	 * this is required to update the residue during intermediate transfer
+	 * completion callback.
+	 */
+	int				processed_stat;
+	u32				sg_len;
+	u32				residue;
+	u32				residue_stat;
+
+	struct edma_pset		pset[0];
+};
+
+struct edma_cc;
+
+struct edma_chan {
+	struct virt_dma_chan		vchan;
+	struct list_head		node;
+	struct edma_desc		*edesc;
+	struct edma_cc			*ecc;
+	int				ch_num;
+	bool				alloced;
+	int				slot[EDMA_MAX_SLOTS];
+	int				missed;
+	struct dma_slave_config		cfg;
+};
+
+struct edma_cc {
+	int				ctlr;
+	struct dma_device		dma_slave;
+	struct edma_chan		slave_chans[EDMA_CHANS];
+	int				num_slave_chans;
+	int				dummy_slot;
+};
+
+static inline struct edma_cc *to_edma_cc(struct dma_device *d)
+{
+	return container_of(d, struct edma_cc, dma_slave);
+}
+
+static inline struct edma_chan *to_edma_chan(struct dma_chan *c)
+{
+	return container_of(c, struct edma_chan, vchan.chan);
+}
+
+static inline struct edma_desc
+*to_edma_desc(struct dma_async_tx_descriptor *tx)
+{
+	return container_of(tx, struct edma_desc, vdesc.tx);
+}
+
+static void edma_desc_free(struct virt_dma_desc *vdesc)
+{
+	kfree(container_of(vdesc, struct edma_desc, vdesc));
+}
+
+/* Dispatch a queued descriptor to the controller (caller holds lock) */
+static void edma_execute(struct edma_chan *echan)
+{
+	struct virt_dma_desc *vdesc;
+	struct edma_desc *edesc;
+	struct device *dev = echan->vchan.chan.device->dev;
+	int i, j, left, nslots;
+
+	/* If either we processed all psets or we're still not started */
+	if (!echan->edesc ||
+	    echan->edesc->pset_nr == echan->edesc->processed) {
+		/* Get next vdesc */
+		vdesc = vchan_next_desc(&echan->vchan);
+		if (!vdesc) {
+			echan->edesc = NULL;
+			return;
+		}
+		list_del(&vdesc->node);
+		echan->edesc = to_edma_desc(&vdesc->tx);
+	}
+
+	edesc = echan->edesc;
+
+	/* Find out how many left */
+	left = edesc->pset_nr - edesc->processed;
+	nslots = min(MAX_NR_SG, left);
+	edesc->sg_len = 0;
+
+	/* Write descriptor PaRAM set(s) */
+	for (i = 0; i < nslots; i++) {
+		j = i + edesc->processed;
+		edma_write_slot(echan->slot[i], &edesc->pset[j].param);
+		edesc->sg_len += edesc->pset[j].len;
+		dev_vdbg(echan->vchan.chan.device->dev,
+			"\n pset[%d]:\n"
+			"  chnum\t%d\n"
+			"  slot\t%d\n"
+			"  opt\t%08x\n"
+			"  src\t%08x\n"
+			"  dst\t%08x\n"
+			"  abcnt\t%08x\n"
+			"  ccnt\t%08x\n"
+			"  bidx\t%08x\n"
+			"  cidx\t%08x\n"
+			"  lkrld\t%08x\n",
+			j, echan->ch_num, echan->slot[i],
+			edesc->pset[j].param.opt,
+			edesc->pset[j].param.src,
+			edesc->pset[j].param.dst,
+			edesc->pset[j].param.a_b_cnt,
+			edesc->pset[j].param.ccnt,
+			edesc->pset[j].param.src_dst_bidx,
+			edesc->pset[j].param.src_dst_cidx,
+			edesc->pset[j].param.link_bcntrld);
+		/* Link to the previous slot if not the last set */
+		if (i != (nslots - 1))
+			edma_link(echan->slot[i], echan->slot[i+1]);
+	}
+
+	edesc->processed += nslots;
+
+	/*
+	 * If this is either the last set in a set of SG-list transactions
+	 * then setup a link to the dummy slot, this results in all future
+	 * events being absorbed and that's OK because we're done
+	 */
+	if (edesc->processed == edesc->pset_nr) {
+		if (edesc->cyclic)
+			edma_link(echan->slot[nslots-1], echan->slot[1]);
+		else
+			edma_link(echan->slot[nslots-1],
+				  echan->ecc->dummy_slot);
+	}
+
+	if (edesc->processed <= MAX_NR_SG) {
+		dev_dbg(dev, "first transfer starting on channel %d\n",
+			echan->ch_num);
+		edma_start(echan->ch_num);
+	} else {
+		dev_dbg(dev, "chan: %d: completed %d elements, resuming\n",
+			echan->ch_num, edesc->processed);
+		edma_resume(echan->ch_num);
+	}
+
+	/*
+	 * This happens due to setup times between intermediate transfers
+	 * in long SG lists which have to be broken up into transfers of
+	 * MAX_NR_SG
+	 */
+	if (echan->missed) {
+		dev_dbg(dev, "missed event on channel %d\n", echan->ch_num);
+		edma_clean_channel(echan->ch_num);
+		edma_stop(echan->ch_num);
+		edma_start(echan->ch_num);
+		edma_trigger_channel(echan->ch_num);
+		echan->missed = 0;
+	}
+}
+
+static int edma_terminate_all(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	unsigned long flags;
+	LIST_HEAD(head);
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+
+	/*
+	 * Stop DMA activity: we assume the callback will not be called
+	 * after edma_dma() returns (even if it does, it will see
+	 * echan->edesc is NULL and exit.)
+	 */
+	if (echan->edesc) {
+		int cyclic = echan->edesc->cyclic;
+
+		/*
+		 * free the running request descriptor
+		 * since it is not in any of the vdesc lists
+		 */
+		edma_desc_free(&echan->edesc->vdesc);
+
+		echan->edesc = NULL;
+		edma_stop(echan->ch_num);
+		/* Move the cyclic channel back to default queue */
+		if (cyclic)
+			edma_assign_channel_eventq(echan->ch_num,
+						   EVENTQ_DEFAULT);
+	}
+
+	vchan_get_all_descriptors(&echan->vchan, &head);
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+	vchan_dma_desc_free_list(&echan->vchan, &head);
+
+	return 0;
+}
+
+static int edma_slave_config(struct dma_chan *chan,
+	struct dma_slave_config *cfg)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+
+	if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
+	    cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
+		return -EINVAL;
+
+	memcpy(&echan->cfg, cfg, sizeof(echan->cfg));
+
+	return 0;
+}
+
+static int edma_dma_pause(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+
+	/* Pause/Resume only allowed with cyclic mode */
+	if (!echan->edesc || !echan->edesc->cyclic)
+		return -EINVAL;
+
+	edma_pause(echan->ch_num);
+	return 0;
+}
+
+static int edma_dma_resume(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+
+	/* Pause/Resume only allowed with cyclic mode */
+	if (!echan->edesc->cyclic)
+		return -EINVAL;
+
+	edma_resume(echan->ch_num);
+	return 0;
+}
+
+/*
+ * A PaRAM set configuration abstraction used by other modes
+ * @chan: Channel who's PaRAM set we're configuring
+ * @pset: PaRAM set to initialize and setup.
+ * @src_addr: Source address of the DMA
+ * @dst_addr: Destination address of the DMA
+ * @burst: In units of dev_width, how much to send
+ * @dev_width: How much is the dev_width
+ * @dma_length: Total length of the DMA transfer
+ * @direction: Direction of the transfer
+ */
+static int edma_config_pset(struct dma_chan *chan, struct edma_pset *epset,
+	dma_addr_t src_addr, dma_addr_t dst_addr, u32 burst,
+	enum dma_slave_buswidth dev_width, unsigned int dma_length,
+	enum dma_transfer_direction direction)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	struct edmacc_param *param = &epset->param;
+	int acnt, bcnt, ccnt, cidx;
+	int src_bidx, dst_bidx, src_cidx, dst_cidx;
+	int absync;
+
+	acnt = dev_width;
+
+	/* src/dst_maxburst == 0 is the same case as src/dst_maxburst == 1 */
+	if (!burst)
+		burst = 1;
+	/*
+	 * If the maxburst is equal to the fifo width, use
+	 * A-synced transfers. This allows for large contiguous
+	 * buffer transfers using only one PaRAM set.
+	 */
+	if (burst == 1) {
+		/*
+		 * For the A-sync case, bcnt and ccnt are the remainder
+		 * and quotient respectively of the division of:
+		 * (dma_length / acnt) by (SZ_64K -1). This is so
+		 * that in case bcnt over flows, we have ccnt to use.
+		 * Note: In A-sync tranfer only, bcntrld is used, but it
+		 * only applies for sg_dma_len(sg) >= SZ_64K.
+		 * In this case, the best way adopted is- bccnt for the
+		 * first frame will be the remainder below. Then for
+		 * every successive frame, bcnt will be SZ_64K-1. This
+		 * is assured as bcntrld = 0xffff in end of function.
+		 */
+		absync = false;
+		ccnt = dma_length / acnt / (SZ_64K - 1);
+		bcnt = dma_length / acnt - ccnt * (SZ_64K - 1);
+		/*
+		 * If bcnt is non-zero, we have a remainder and hence an
+		 * extra frame to transfer, so increment ccnt.
+		 */
+		if (bcnt)
+			ccnt++;
+		else
+			bcnt = SZ_64K - 1;
+		cidx = acnt;
+	} else {
+		/*
+		 * If maxburst is greater than the fifo address_width,
+		 * use AB-synced transfers where A count is the fifo
+		 * address_width and B count is the maxburst. In this
+		 * case, we are limited to transfers of C count frames
+		 * of (address_width * maxburst) where C count is limited
+		 * to SZ_64K-1. This places an upper bound on the length
+		 * of an SG segment that can be handled.
+		 */
+		absync = true;
+		bcnt = burst;
+		ccnt = dma_length / (acnt * bcnt);
+		if (ccnt > (SZ_64K - 1)) {
+			dev_err(dev, "Exceeded max SG segment size\n");
+			return -EINVAL;
+		}
+		cidx = acnt * bcnt;
+	}
+
+	epset->len = dma_length;
+
+	if (direction == DMA_MEM_TO_DEV) {
+		src_bidx = acnt;
+		src_cidx = cidx;
+		dst_bidx = 0;
+		dst_cidx = 0;
+		epset->addr = src_addr;
+	} else if (direction == DMA_DEV_TO_MEM)  {
+		src_bidx = 0;
+		src_cidx = 0;
+		dst_bidx = acnt;
+		dst_cidx = cidx;
+		epset->addr = dst_addr;
+	} else if (direction == DMA_MEM_TO_MEM)  {
+		src_bidx = acnt;
+		src_cidx = cidx;
+		dst_bidx = acnt;
+		dst_cidx = cidx;
+	} else {
+		dev_err(dev, "%s: direction not implemented yet\n", __func__);
+		return -EINVAL;
+	}
+
+	param->opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
+	/* Configure A or AB synchronized transfers */
+	if (absync)
+		param->opt |= SYNCDIM;
+
+	param->src = src_addr;
+	param->dst = dst_addr;
+
+	param->src_dst_bidx = (dst_bidx << 16) | src_bidx;
+	param->src_dst_cidx = (dst_cidx << 16) | src_cidx;
+
+	param->a_b_cnt = bcnt << 16 | acnt;
+	param->ccnt = ccnt;
+	/*
+	 * Only time when (bcntrld) auto reload is required is for
+	 * A-sync case, and in this case, a requirement of reload value
+	 * of SZ_64K-1 only is assured. 'link' is initially set to NULL
+	 * and then later will be populated by edma_execute.
+	 */
+	param->link_bcntrld = 0xffffffff;
+	return absync;
+}
+
+static struct dma_async_tx_descriptor *edma_prep_slave_sg(
+	struct dma_chan *chan, struct scatterlist *sgl,
+	unsigned int sg_len, enum dma_transfer_direction direction,
+	unsigned long tx_flags, void *context)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	struct edma_desc *edesc;
+	dma_addr_t src_addr = 0, dst_addr = 0;
+	enum dma_slave_buswidth dev_width;
+	u32 burst;
+	struct scatterlist *sg;
+	int i, nslots, ret;
+
+	if (unlikely(!echan || !sgl || !sg_len))
+		return NULL;
+
+	if (direction == DMA_DEV_TO_MEM) {
+		src_addr = echan->cfg.src_addr;
+		dev_width = echan->cfg.src_addr_width;
+		burst = echan->cfg.src_maxburst;
+	} else if (direction == DMA_MEM_TO_DEV) {
+		dst_addr = echan->cfg.dst_addr;
+		dev_width = echan->cfg.dst_addr_width;
+		burst = echan->cfg.dst_maxburst;
+	} else {
+		dev_err(dev, "%s: bad direction: %d\n", __func__, direction);
+		return NULL;
+	}
+
+	if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+		dev_err(dev, "%s: Undefined slave buswidth\n", __func__);
+		return NULL;
+	}
+
+	edesc = kzalloc(sizeof(*edesc) + sg_len *
+		sizeof(edesc->pset[0]), GFP_ATOMIC);
+	if (!edesc) {
+		dev_err(dev, "%s: Failed to allocate a descriptor\n", __func__);
+		return NULL;
+	}
+
+	edesc->pset_nr = sg_len;
+	edesc->residue = 0;
+	edesc->direction = direction;
+	edesc->echan = echan;
+
+	/* Allocate a PaRAM slot, if needed */
+	nslots = min_t(unsigned, MAX_NR_SG, sg_len);
+
+	for (i = 0; i < nslots; i++) {
+		if (echan->slot[i] < 0) {
+			echan->slot[i] =
+				edma_alloc_slot(EDMA_CTLR(echan->ch_num),
+						EDMA_SLOT_ANY);
+			if (echan->slot[i] < 0) {
+				kfree(edesc);
+				dev_err(dev, "%s: Failed to allocate slot\n",
+					__func__);
+				return NULL;
+			}
+		}
+	}
+
+	/* Configure PaRAM sets for each SG */
+	for_each_sg(sgl, sg, sg_len, i) {
+		/* Get address for each SG */
+		if (direction == DMA_DEV_TO_MEM)
+			dst_addr = sg_dma_address(sg);
+		else
+			src_addr = sg_dma_address(sg);
+
+		ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
+				       dst_addr, burst, dev_width,
+				       sg_dma_len(sg), direction);
+		if (ret < 0) {
+			kfree(edesc);
+			return NULL;
+		}
+
+		edesc->absync = ret;
+		edesc->residue += sg_dma_len(sg);
+
+		/* If this is the last in a current SG set of transactions,
+		   enable interrupts so that next set is processed */
+		if (!((i+1) % MAX_NR_SG))
+			edesc->pset[i].param.opt |= TCINTEN;
+
+		/* If this is the last set, enable completion interrupt flag */
+		if (i == sg_len - 1)
+			edesc->pset[i].param.opt |= TCINTEN;
+	}
+	edesc->residue_stat = edesc->residue;
+
+	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
+static struct dma_async_tx_descriptor *edma_prep_dma_memcpy(
+	struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+	size_t len, unsigned long tx_flags)
+{
+	int ret;
+	struct edma_desc *edesc;
+	struct device *dev = chan->device->dev;
+	struct edma_chan *echan = to_edma_chan(chan);
+
+	if (unlikely(!echan || !len))
+		return NULL;
+
+	edesc = kzalloc(sizeof(*edesc) + sizeof(edesc->pset[0]), GFP_ATOMIC);
+	if (!edesc) {
+		dev_dbg(dev, "Failed to allocate a descriptor\n");
+		return NULL;
+	}
+
+	edesc->pset_nr = 1;
+
+	ret = edma_config_pset(chan, &edesc->pset[0], src, dest, 1,
+			       DMA_SLAVE_BUSWIDTH_4_BYTES, len, DMA_MEM_TO_MEM);
+	if (ret < 0)
+		return NULL;
+
+	edesc->absync = ret;
+
+	/*
+	 * Enable intermediate transfer chaining to re-trigger channel
+	 * on completion of every TR, and enable transfer-completion
+	 * interrupt on completion of the whole transfer.
+	 */
+	edesc->pset[0].param.opt |= ITCCHEN;
+	edesc->pset[0].param.opt |= TCINTEN;
+
+	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
+static struct dma_async_tx_descriptor *edma_prep_dma_cyclic(
+	struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
+	size_t period_len, enum dma_transfer_direction direction,
+	unsigned long tx_flags)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	struct edma_desc *edesc;
+	dma_addr_t src_addr, dst_addr;
+	enum dma_slave_buswidth dev_width;
+	u32 burst;
+	int i, ret, nslots;
+
+	if (unlikely(!echan || !buf_len || !period_len))
+		return NULL;
+
+	if (direction == DMA_DEV_TO_MEM) {
+		src_addr = echan->cfg.src_addr;
+		dst_addr = buf_addr;
+		dev_width = echan->cfg.src_addr_width;
+		burst = echan->cfg.src_maxburst;
+	} else if (direction == DMA_MEM_TO_DEV) {
+		src_addr = buf_addr;
+		dst_addr = echan->cfg.dst_addr;
+		dev_width = echan->cfg.dst_addr_width;
+		burst = echan->cfg.dst_maxburst;
+	} else {
+		dev_err(dev, "%s: bad direction: %d\n", __func__, direction);
+		return NULL;
+	}
+
+	if (dev_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
+		dev_err(dev, "%s: Undefined slave buswidth\n", __func__);
+		return NULL;
+	}
+
+	if (unlikely(buf_len % period_len)) {
+		dev_err(dev, "Period should be multiple of Buffer length\n");
+		return NULL;
+	}
+
+	nslots = (buf_len / period_len) + 1;
+
+	/*
+	 * Cyclic DMA users such as audio cannot tolerate delays introduced
+	 * by cases where the number of periods is more than the maximum
+	 * number of SGs the EDMA driver can handle at a time. For DMA types
+	 * such as Slave SGs, such delays are tolerable and synchronized,
+	 * but the synchronization is difficult to achieve with Cyclic and
+	 * cannot be guaranteed, so we error out early.
+	 */
+	if (nslots > MAX_NR_SG)
+		return NULL;
+
+	edesc = kzalloc(sizeof(*edesc) + nslots *
+		sizeof(edesc->pset[0]), GFP_ATOMIC);
+	if (!edesc) {
+		dev_err(dev, "%s: Failed to allocate a descriptor\n", __func__);
+		return NULL;
+	}
+
+	edesc->cyclic = 1;
+	edesc->pset_nr = nslots;
+	edesc->residue = edesc->residue_stat = buf_len;
+	edesc->direction = direction;
+	edesc->echan = echan;
+
+	dev_dbg(dev, "%s: channel=%d nslots=%d period_len=%zu buf_len=%zu\n",
+		__func__, echan->ch_num, nslots, period_len, buf_len);
+
+	for (i = 0; i < nslots; i++) {
+		/* Allocate a PaRAM slot, if needed */
+		if (echan->slot[i] < 0) {
+			echan->slot[i] =
+				edma_alloc_slot(EDMA_CTLR(echan->ch_num),
+						EDMA_SLOT_ANY);
+			if (echan->slot[i] < 0) {
+				kfree(edesc);
+				dev_err(dev, "%s: Failed to allocate slot\n",
+					__func__);
+				return NULL;
+			}
+		}
+
+		if (i == nslots - 1) {
+			memcpy(&edesc->pset[i], &edesc->pset[0],
+			       sizeof(edesc->pset[0]));
+			break;
+		}
+
+		ret = edma_config_pset(chan, &edesc->pset[i], src_addr,
+				       dst_addr, burst, dev_width, period_len,
+				       direction);
+		if (ret < 0) {
+			kfree(edesc);
+			return NULL;
+		}
+
+		if (direction == DMA_DEV_TO_MEM)
+			dst_addr += period_len;
+		else
+			src_addr += period_len;
+
+		dev_vdbg(dev, "%s: Configure period %d of buf:\n", __func__, i);
+		dev_vdbg(dev,
+			"\n pset[%d]:\n"
+			"  chnum\t%d\n"
+			"  slot\t%d\n"
+			"  opt\t%08x\n"
+			"  src\t%08x\n"
+			"  dst\t%08x\n"
+			"  abcnt\t%08x\n"
+			"  ccnt\t%08x\n"
+			"  bidx\t%08x\n"
+			"  cidx\t%08x\n"
+			"  lkrld\t%08x\n",
+			i, echan->ch_num, echan->slot[i],
+			edesc->pset[i].param.opt,
+			edesc->pset[i].param.src,
+			edesc->pset[i].param.dst,
+			edesc->pset[i].param.a_b_cnt,
+			edesc->pset[i].param.ccnt,
+			edesc->pset[i].param.src_dst_bidx,
+			edesc->pset[i].param.src_dst_cidx,
+			edesc->pset[i].param.link_bcntrld);
+
+		edesc->absync = ret;
+
+		/*
+		 * Enable period interrupt only if it is requested
+		 */
+		if (tx_flags & DMA_PREP_INTERRUPT)
+			edesc->pset[i].param.opt |= TCINTEN;
+	}
+
+	/* Place the cyclic channel to highest priority queue */
+	edma_assign_channel_eventq(echan->ch_num, EVENTQ_0);
+
+	return vchan_tx_prep(&echan->vchan, &edesc->vdesc, tx_flags);
+}
+
+static void edma_callback(unsigned ch_num, u16 ch_status, void *data)
+{
+	struct edma_chan *echan = data;
+	struct device *dev = echan->vchan.chan.device->dev;
+	struct edma_desc *edesc;
+	struct edmacc_param p;
+
+	edesc = echan->edesc;
+
+	/* Pause the channel for non-cyclic */
+	if (!edesc || (edesc && !edesc->cyclic))
+		edma_pause(echan->ch_num);
+
+	switch (ch_status) {
+	case EDMA_DMA_COMPLETE:
+		spin_lock(&echan->vchan.lock);
+
+		if (edesc) {
+			if (edesc->cyclic) {
+				vchan_cyclic_callback(&edesc->vdesc);
+			} else if (edesc->processed == edesc->pset_nr) {
+				dev_dbg(dev, "Transfer complete, stopping channel %d\n", ch_num);
+				edesc->residue = 0;
+				edma_stop(echan->ch_num);
+				vchan_cookie_complete(&edesc->vdesc);
+				edma_execute(echan);
+			} else {
+				dev_dbg(dev, "Intermediate transfer complete on channel %d\n", ch_num);
+
+				/* Update statistics for tx_status */
+				edesc->residue -= edesc->sg_len;
+				edesc->residue_stat = edesc->residue;
+				edesc->processed_stat = edesc->processed;
+
+				edma_execute(echan);
+			}
+		}
+
+		spin_unlock(&echan->vchan.lock);
+
+		break;
+	case EDMA_DMA_CC_ERROR:
+		spin_lock(&echan->vchan.lock);
+
+		edma_read_slot(EDMA_CHAN_SLOT(echan->slot[0]), &p);
+
+		/*
+		 * Issue later based on missed flag which will be sure
+		 * to happen as:
+		 * (1) we finished transmitting an intermediate slot and
+		 *     edma_execute is coming up.
+		 * (2) or we finished current transfer and issue will
+		 *     call edma_execute.
+		 *
+		 * Important note: issuing can be dangerous here and
+		 * lead to some nasty recursion when we are in a NULL
+		 * slot. So we avoid doing so and set the missed flag.
+		 */
+		if (p.a_b_cnt == 0 && p.ccnt == 0) {
+			dev_dbg(dev, "Error occurred, looks like slot is null, just setting miss\n");
+			echan->missed = 1;
+		} else {
+			/*
+			 * The slot is already programmed but the event got
+			 * missed, so its safe to issue it here.
+			 */
+			dev_dbg(dev, "Error occurred but slot is non-null, TRIGGERING\n");
+			edma_clean_channel(echan->ch_num);
+			edma_stop(echan->ch_num);
+			edma_start(echan->ch_num);
+			edma_trigger_channel(echan->ch_num);
+		}
+
+		spin_unlock(&echan->vchan.lock);
+
+		break;
+	default:
+		break;
+	}
+}
+
+/* Alloc channel resources */
+static int edma_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	int ret;
+	int a_ch_num;
+	LIST_HEAD(descs);
+
+	a_ch_num = edma_alloc_channel(echan->ch_num, edma_callback,
+					echan, EVENTQ_DEFAULT);
+
+	if (a_ch_num < 0) {
+		ret = -ENODEV;
+		goto err_no_chan;
+	}
+
+	if (a_ch_num != echan->ch_num) {
+		dev_err(dev, "failed to allocate requested channel %u:%u\n",
+			EDMA_CTLR(echan->ch_num),
+			EDMA_CHAN_SLOT(echan->ch_num));
+		ret = -ENODEV;
+		goto err_wrong_chan;
+	}
+
+	echan->alloced = true;
+	echan->slot[0] = echan->ch_num;
+
+	dev_dbg(dev, "allocated channel %d for %u:%u\n", echan->ch_num,
+		EDMA_CTLR(echan->ch_num), EDMA_CHAN_SLOT(echan->ch_num));
+
+	return 0;
+
+err_wrong_chan:
+	edma_free_channel(a_ch_num);
+err_no_chan:
+	return ret;
+}
+
+/* Free channel resources */
+static void edma_free_chan_resources(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct device *dev = chan->device->dev;
+	int i;
+
+	/* Terminate transfers */
+	edma_stop(echan->ch_num);
+
+	vchan_free_chan_resources(&echan->vchan);
+
+	/* Free EDMA PaRAM slots */
+	for (i = 1; i < EDMA_MAX_SLOTS; i++) {
+		if (echan->slot[i] >= 0) {
+			edma_free_slot(echan->slot[i]);
+			echan->slot[i] = -1;
+		}
+	}
+
+	/* Free EDMA channel */
+	if (echan->alloced) {
+		edma_free_channel(echan->ch_num);
+		echan->alloced = false;
+	}
+
+	dev_dbg(dev, "freeing channel for %u\n", echan->ch_num);
+}
+
+/* Send pending descriptor to hardware */
+static void edma_issue_pending(struct dma_chan *chan)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	unsigned long flags;
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+	if (vchan_issue_pending(&echan->vchan) && !echan->edesc)
+		edma_execute(echan);
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+}
+
+static u32 edma_residue(struct edma_desc *edesc)
+{
+	bool dst = edesc->direction == DMA_DEV_TO_MEM;
+	struct edma_pset *pset = edesc->pset;
+	dma_addr_t done, pos;
+	int i;
+
+	/*
+	 * We always read the dst/src position from the first RamPar
+	 * pset. That's the one which is active now.
+	 */
+	pos = edma_get_position(edesc->echan->slot[0], dst);
+
+	/*
+	 * Cyclic is simple. Just subtract pset[0].addr from pos.
+	 *
+	 * We never update edesc->residue in the cyclic case, so we
+	 * can tell the remaining room to the end of the circular
+	 * buffer.
+	 */
+	if (edesc->cyclic) {
+		done = pos - pset->addr;
+		edesc->residue_stat = edesc->residue - done;
+		return edesc->residue_stat;
+	}
+
+	/*
+	 * For SG operation we catch up with the last processed
+	 * status.
+	 */
+	pset += edesc->processed_stat;
+
+	for (i = edesc->processed_stat; i < edesc->processed; i++, pset++) {
+		/*
+		 * If we are inside this pset address range, we know
+		 * this is the active one. Get the current delta and
+		 * stop walking the psets.
+		 */
+		if (pos >= pset->addr && pos < pset->addr + pset->len)
+			return edesc->residue_stat - (pos - pset->addr);
+
+		/* Otherwise mark it done and update residue_stat. */
+		edesc->processed_stat++;
+		edesc->residue_stat -= pset->len;
+	}
+	return edesc->residue_stat;
+}
+
+/* Check request completion status */
+static enum dma_status edma_tx_status(struct dma_chan *chan,
+				      dma_cookie_t cookie,
+				      struct dma_tx_state *txstate)
+{
+	struct edma_chan *echan = to_edma_chan(chan);
+	struct virt_dma_desc *vdesc;
+	enum dma_status ret;
+	unsigned long flags;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret == DMA_COMPLETE || !txstate)
+		return ret;
+
+	spin_lock_irqsave(&echan->vchan.lock, flags);
+	if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie)
+		txstate->residue = edma_residue(echan->edesc);
+	else if ((vdesc = vchan_find_desc(&echan->vchan, cookie)))
+		txstate->residue = to_edma_desc(&vdesc->tx)->residue;
+	spin_unlock_irqrestore(&echan->vchan.lock, flags);
+
+	return ret;
+}
+
+static void __init edma_chan_init(struct edma_cc *ecc,
+				  struct dma_device *dma,
+				  struct edma_chan *echans)
+{
+	int i, j;
+
+	for (i = 0; i < EDMA_CHANS; i++) {
+		struct edma_chan *echan = &echans[i];
+		echan->ch_num = EDMA_CTLR_CHAN(ecc->ctlr, i);
+		echan->ecc = ecc;
+		echan->vchan.desc_free = edma_desc_free;
+
+		vchan_init(&echan->vchan, dma);
+
+		INIT_LIST_HEAD(&echan->node);
+		for (j = 0; j < EDMA_MAX_SLOTS; j++)
+			echan->slot[j] = -1;
+	}
+}
+
+#define EDMA_DMA_BUSWIDTHS	(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_3_BYTES) | \
+				 BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))
+
+static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
+			  struct device *dev)
+{
+	dma->device_prep_slave_sg = edma_prep_slave_sg;
+	dma->device_prep_dma_cyclic = edma_prep_dma_cyclic;
+	dma->device_prep_dma_memcpy = edma_prep_dma_memcpy;
+	dma->device_alloc_chan_resources = edma_alloc_chan_resources;
+	dma->device_free_chan_resources = edma_free_chan_resources;
+	dma->device_issue_pending = edma_issue_pending;
+	dma->device_tx_status = edma_tx_status;
+	dma->device_config = edma_slave_config;
+	dma->device_pause = edma_dma_pause;
+	dma->device_resume = edma_dma_resume;
+	dma->device_terminate_all = edma_terminate_all;
+
+	dma->src_addr_widths = EDMA_DMA_BUSWIDTHS;
+	dma->dst_addr_widths = EDMA_DMA_BUSWIDTHS;
+	dma->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+	dma->residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
+
+	dma->dev = dev;
+
+	/*
+	 * code using dma memcpy must make sure alignment of
+	 * length is at dma->copy_align boundary.
+	 */
+	dma->copy_align = DMA_SLAVE_BUSWIDTH_4_BYTES;
+
+	INIT_LIST_HEAD(&dma->channels);
+}
+
+static int edma_probe(struct platform_device *pdev)
+{
+	struct edma_cc *ecc;
+	int ret;
+
+	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
+	ecc = devm_kzalloc(&pdev->dev, sizeof(*ecc), GFP_KERNEL);
+	if (!ecc) {
+		dev_err(&pdev->dev, "Can't allocate controller\n");
+		return -ENOMEM;
+	}
+
+	ecc->ctlr = pdev->id;
+	ecc->dummy_slot = edma_alloc_slot(ecc->ctlr, EDMA_SLOT_ANY);
+	if (ecc->dummy_slot < 0) {
+		dev_err(&pdev->dev, "Can't allocate PaRAM dummy slot\n");
+		return ecc->dummy_slot;
+	}
+
+	dma_cap_zero(ecc->dma_slave.cap_mask);
+	dma_cap_set(DMA_SLAVE, ecc->dma_slave.cap_mask);
+	dma_cap_set(DMA_CYCLIC, ecc->dma_slave.cap_mask);
+	dma_cap_set(DMA_MEMCPY, ecc->dma_slave.cap_mask);
+
+	edma_dma_init(ecc, &ecc->dma_slave, &pdev->dev);
+
+	edma_chan_init(ecc, &ecc->dma_slave, ecc->slave_chans);
+
+	ret = dma_async_device_register(&ecc->dma_slave);
+	if (ret)
+		goto err_reg1;
+
+	platform_set_drvdata(pdev, ecc);
+
+	dev_info(&pdev->dev, "TI EDMA DMA engine driver\n");
+
+	return 0;
+
+err_reg1:
+	edma_free_slot(ecc->dummy_slot);
+	return ret;
+}
+
+static int edma_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct edma_cc *ecc = dev_get_drvdata(dev);
+
+	dma_async_device_unregister(&ecc->dma_slave);
+	edma_free_slot(ecc->dummy_slot);
+
+	return 0;
+}
+
+static struct platform_driver edma_driver = {
+	.probe		= edma_probe,
+	.remove		= edma_remove,
+	.driver = {
+		.name = "edma-dma-engine",
+	},
+};
+
+bool edma_filter_fn(struct dma_chan *chan, void *param)
+{
+	if (chan->device->dev->driver == &edma_driver.driver) {
+		struct edma_chan *echan = to_edma_chan(chan);
+		unsigned ch_req = *(unsigned *)param;
+		return ch_req == echan->ch_num;
+	}
+	return false;
+}
+EXPORT_SYMBOL(edma_filter_fn);
+
+static int edma_init(void)
+{
+	return platform_driver_register(&edma_driver);
+}
+subsys_initcall(edma_init);
+
+static void __exit edma_exit(void)
+{
+	platform_driver_unregister(&edma_driver);
+}
+module_exit(edma_exit);
+
+MODULE_AUTHOR("Matt Porter <matt.porter@linaro.org>");
+MODULE_DESCRIPTION("TI EDMA DMA engine driver");
+MODULE_LICENSE("GPL v2");