Subject: [PATCH v2 1/3] dmaengine: add TI EDMA DMA engine driver

From: [email-masked] (Matt Porter)
Date: Wed, 22 Aug 2012 13:10:26 -0400

On Wed, Aug 22, 2012 at 12:37:18PM +0000, Hebbar, Gururaja wrote:
> On Wed, Aug 22, 2012 at 00:13:07, Porter, Matt wrote:
> > Add a DMA engine driver for the TI EDMA controller. This driver
> > is implemented as a wrapper around the existing DaVinci private
> > DMA implementation. This approach allows for incremental conversion
> > of each peripheral driver to the DMA engine API. The EDMA driver
> > supports slave transfers but does not yet support cyclic transfers.
> > 
> > Signed-off-by: Matt Porter <[email-masked]>
> > ---
> >  drivers/dma/Kconfig  |   10 +
> >  drivers/dma/Makefile |    1 +
> >  drivers/dma/edma.c   |  684 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >  include/linux/edma.h |   29 +++
> >  4 files changed, 724 insertions(+)
> >  create mode 100644 drivers/dma/edma.c
> >  create mode 100644 include/linux/edma.h
> > 
> > diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> > index d06ea29..5064e85 100644
> > --- a/drivers/dma/Kconfig
> > +++ b/drivers/dma/Kconfig
> > @@ -208,6 +208,16 @@ config SIRF_DMA
> >  	help
> >  	  Enable support for the CSR SiRFprimaII DMA engine.
> >  
> > +config TI_EDMA
> > +	tristate "TI EDMA support"
> > +	depends on ARCH_DAVINCI
> > +	select DMA_ENGINE
> > +	select DMA_VIRTUAL_CHANNELS
> > +	default y
> > +	help
> > +	  Enable support for the TI EDMA controller. This DMA
> > +	  engine is found on TI DaVinci and AM33xx parts.
> > +
> >  config ARCH_HAS_ASYNC_TX_FIND_CHANNEL
> >  	bool
> >  
> > diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> > index 4cf6b12..f5cf310 100644
> > --- a/drivers/dma/Makefile
> > +++ b/drivers/dma/Makefile
> > @@ -23,6 +23,7 @@ obj-$(CONFIG_IMX_DMA) += imx-dma.o
> >  obj-$(CONFIG_MXS_DMA) += mxs-dma.o
> >  obj-$(CONFIG_TIMB_DMA) += timb_dma.o
> >  obj-$(CONFIG_SIRF_DMA) += sirf-dma.o
> > +obj-$(CONFIG_TI_EDMA) += edma.o
> >  obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
> >  obj-$(CONFIG_TEGRA20_APB_DMA) += tegra20-apb-dma.o
> >  obj-$(CONFIG_PL330_DMA) += pl330.o
> > diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
> > new file mode 100644
> > index 0000000..bf15f81
> > --- /dev/null
> > +++ b/drivers/dma/edma.c
> > @@ -0,0 +1,684 @@
> > +/*
> > + * 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/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 <mach/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 */
> 
> I believe you already have some modifications for your next version to handle
> Different EDMA IP versions (AM335x). 
> They use/have cross-bar implementations as-well.

I don't have those yet. That effort is a WIP atm. However, I should 
probably add more details to the approach I mentioned in the cover
letter for this series.  AM335x support will happen by migrating the
private EDMA API to arm/common/. There's an incremental change
to the private EDMA API implementation to handle AM335x's cross-bar
support that exists right now only in the TI vendor tree. I'm going
to add that, align the platform devices generated from hwmod data
with the existing private EDMA driver expectations, and also add
the DT bindings necessary to communicate all the hardware config
that's currently carried in the mach-davinci/ board files. That
will enable the private EDMA API on AM335x. What I have pushed so
far to my WIP branch is:

https://github.com/ohporter/linux/tree/WIP/edma-dmaengine-private-migration

Completely non-functional on AM335x, but you can at least see
where I'm going there. I'm working on the pdev/pdata/DT part
mentioned above atm.

In turn, since this driver is completely self-contained and
sits only on top of the private EDMA API, it will then work
on AM335x. This approach avoids having to first convert the
remaining McASP driver (also requiring addition of cyclic
transfer support) and refactoring the private EDMA API into
drivers/dma/edma.c. Instead we can get this wrapper driver
immediately working for AM335x at least for slave transfers.
Then go back to handle cyclic/McASP...then the later private
EDMA API removal.

> 
> > +
> > +/* Max of 16 segments per channel to conserve PaRAM slots */
> > +#define MAX_NR_SG		16
> > +#define EDMA_MAX_SLOTS		MAX_NR_SG
> 
> Is it possible to get this (EDMA_MAX_SLOTS) from platform data?

Absolutely. Once the private EDMA API goes away. The whole
point of this driver is to be completely standalone around
the private EDMA API.

Also, keep in mind that this is an arbitrary value chosen to
handle the fact that we have this finite resource of PaRAM slots
and we can't have a single channel getting allocated and someone
passing in a scatterlist that will consume every slot in the
system. Doing a better job of managing the slot resources is
something that's on the long-range list. Right now it's more
important to address just getting all the drivers converted
and support on both davinci and omap2+.

> 
> > +#define EDMA_DESCRIPTORS	16
> > +
> > +struct edma_desc {
> > +	struct virt_dma_desc		vdesc;
> > +	struct list_head		node;
> > +
> > +	int				absync;
> > +	int				pset_nr;
> > +	struct edmacc_param		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];
> > +
> > +	dma_addr_t			addr;
> > +	int				addr_width;
> > +	int				maxburst;
> > +};
> > +
> > +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 = vchan_next_desc(&echan->vchan);
> > +	struct edma_desc *edesc;
> > +	int i;
> > +
> > +	if (!vdesc) {
> > +		echan->edesc = NULL;
> > +		return;
> > +	}
> > +
> > +	list_del(&vdesc->node);
> > +
> > +	echan->edesc = edesc = to_edma_desc(&vdesc->tx);
> > +
> > +	/* Write descriptor PaRAM set(s) */
> > +	for (i = 0; i < edesc->pset_nr; i++) {
> > +		edma_write_slot(echan->slot[i], &edesc->pset[i]);
> > +		dev_dbg(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",
> > +			i, echan->ch_num, echan->slot[i],
> > +			edesc->pset[i].opt,
> > +			edesc->pset[i].src,
> > +			edesc->pset[i].dst,
> > +			edesc->pset[i].a_b_cnt,
> > +			edesc->pset[i].ccnt,
> > +			edesc->pset[i].src_dst_bidx,
> > +			edesc->pset[i].src_dst_cidx,
> > +			edesc->pset[i].link_bcntrld);
> > +		/* Link to the previous slot if not the last set */
> > +		if (i != (edesc->pset_nr - 1))
> > +			edma_link(echan->slot[i], echan->slot[i+1]);
> > +		/* Final pset links to the dummy pset */
> > +		else
> > +			edma_link(echan->slot[i], echan->ecc->dummy_slot);
> > +	}
> > +
> > +	edma_start(echan->ch_num);
> > +}
> > +
> > +static int edma_terminate_all(struct edma_chan *echan)
> > +{
> > +	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) {
> > +		echan->edesc = NULL;
> > +		edma_stop(echan->ch_num);
> > +	}
> > +
> > +	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 edma_chan *echan,
> > +	struct dma_slave_config *config)
> > +{
> > +	if ((config->src_addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES) ||
> > +		(config->dst_addr_width > DMA_SLAVE_BUSWIDTH_4_BYTES))
> > +		return -EINVAL;
> > +
> > +	if (config->direction == DMA_MEM_TO_DEV) {
> > +		if (config->dst_addr)
> > +			echan->addr = config->dst_addr;
> > +		if (config->dst_addr_width)
> > +			echan->addr_width = config->dst_addr_width;
> > +		if (config->dst_maxburst)
> > +			echan->maxburst = config->dst_maxburst;
> > +	} else if (config->direction == DMA_DEV_TO_MEM) {
> > +		if (config->src_addr)
> > +			echan->addr = config->src_addr;
> > +		if (config->src_addr_width)
> > +			echan->addr_width = config->src_addr_width;
> > +		if (config->src_maxburst)
> > +			echan->maxburst = config->src_maxburst;
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int edma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> > +			unsigned long arg)
> > +{
> > +	int ret = 0;
> > +	struct dma_slave_config *config;
> > +	struct edma_chan *echan = to_edma_chan(chan);
> > +
> > +	switch (cmd) {
> > +	case DMA_TERMINATE_ALL:
> > +		edma_terminate_all(echan);
> > +		break;
> > +	case DMA_SLAVE_CONFIG:
> > +		config = (struct dma_slave_config *)arg;
> > +		ret = edma_slave_config(echan, config);
> > +		break;
> > +	default:
> > +		ret = -ENOSYS;
> > +	}
> > +
> > +	return ret;
> > +}
> > +
> > +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 = echan->vchan.chan.device->dev;
> > +	struct edma_desc *edesc;
> > +	struct scatterlist *sg;
> > +	int i;
> > +	int acnt, bcnt, ccnt, src, dst, cidx;
> > +	int src_bidx, dst_bidx, src_cidx, dst_cidx;
> > +
> > +	if (unlikely(!echan || !sgl || !sg_len))
> > +		return NULL;
> > +
> > +	if (echan->addr_width == DMA_SLAVE_BUSWIDTH_UNDEFINED) {
> > +		dev_err(dev, "Undefined slave buswidth\n");
> > +		return NULL;
> > +	}
> > +
> > +	if (sg_len > MAX_NR_SG) {
> > +		dev_err(dev, "Exceeded max SG segments %d > %d\n",
> > +			sg_len, MAX_NR_SG);
> > +		return NULL;
> > +	}
> > +
> > +	edesc = kzalloc(sizeof(*edesc) + sg_len *
> > +		sizeof(edesc->pset[0]), GFP_ATOMIC);
> > +	if (!edesc) {
> > +		dev_dbg(dev, "Failed to allocate a descriptor\n");
> > +		return NULL;
> > +	}
> > +
> > +	edesc->pset_nr = sg_len;
> > +
> > +	for_each_sg(sgl, sg, sg_len, 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) {
> > +				dev_err(dev, "Failed to allocate slot\n");
> > +				return NULL;
> > +			}
> > +		}
> > +
> > +		acnt = echan->addr_width;
> > +
> > +		/*
> > +		 * 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 (echan->maxburst == 1) {
> > +			edesc->absync = false;
> > +			ccnt = sg_dma_len(sg) / acnt / (SZ_64K - 1);
> > +			bcnt = sg_dma_len(sg) / acnt - ccnt * (SZ_64K - 1);
> > +			if (bcnt)
> > +				ccnt++;
> > +			else
> > +				bcnt = SZ_64K - 1;
> > +			cidx = acnt;
> > +		/*
> > +		 * 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.
> > +		 */
> > +		} else {
> > +			edesc->absync = true;
> > +			bcnt = echan->maxburst;
> > +			ccnt = sg_dma_len(sg) / (acnt * bcnt);
> > +			if (ccnt > (SZ_64K - 1)) {
> > +				dev_err(dev, "Exceeded max SG segment size\n");
> > +				return NULL;
> > +			}
> > +			cidx = acnt * bcnt;
> > +		}
> > +
> > +		if (direction == DMA_MEM_TO_DEV) {
> > +			src = sg_dma_address(sg);
> > +			dst = echan->addr;
> > +			src_bidx = acnt;
> > +			src_cidx = cidx;
> > +			dst_bidx = 0;
> > +			dst_cidx = 0;
> > +		} else {
> > +			src = echan->addr;
> > +			dst = sg_dma_address(sg);
> > +			src_bidx = 0;
> > +			src_cidx = 0;
> > +			dst_bidx = acnt;
> > +			dst_cidx = cidx;
> > +		}
> > +
> > +		edesc->pset[i].opt = EDMA_TCC(EDMA_CHAN_SLOT(echan->ch_num));
> > +		/* Configure A or AB synchronized transfers */
> > +		if (edesc->absync)
> > +			edesc->pset[i].opt |= SYNCDIM;
> > +		/* If this is the last set, enable completion interrupt flag */
> > +		if (i == sg_len - 1)
> > +			edesc->pset[i].opt |= TCINTEN;
> > +
> > +		edesc->pset[i].src = src;
> > +		edesc->pset[i].dst = dst;
> > +
> > +		edesc->pset[i].src_dst_bidx = (dst_bidx << 16) | src_bidx;
> > +		edesc->pset[i].src_dst_cidx = (dst_cidx << 16) | src_cidx;
> > +
> > +		edesc->pset[i].a_b_cnt = bcnt << 16 | acnt;
> > +		edesc->pset[i].ccnt = ccnt;
> > +		edesc->pset[i].link_bcntrld = 0xffffffff;
> > +
> > +	}
> > +
> > +	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;
> > +	unsigned long flags;
> > +
> > +	/* Stop the channel */
> > +	edma_stop(echan->ch_num);
> > +
> > +	switch (ch_status) {
> > +	case DMA_COMPLETE:
> > +		dev_dbg(dev, "transfer complete on channel %d\n", ch_num);
> > +
> > +		spin_lock_irqsave(&echan->vchan.lock, flags);
> > +
> > +		edesc = echan->edesc;
> > +		if (edesc) {
> > +			edma_execute(echan);
> > +			vchan_cookie_complete(&edesc->vdesc);
> > +		}
> > +
> > +		spin_unlock_irqrestore(&echan->vchan.lock, flags);
> > +
> > +		break;
> > +	case DMA_CC_ERROR:
> > +		dev_dbg(dev, "transfer error on channel %d\n", ch_num);
> > +		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 = echan->vchan.chan.device->dev;
> > +	int ret;
> > +	int a_ch_num;
> > +	LIST_HEAD(descs);
> > +
> > +	a_ch_num = edma_alloc_channel(echan->ch_num, edma_callback,
> > +					chan, 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_info(dev, "allocated channel for %u:%u\n",
> > +		 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 = echan->vchan.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_info(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 size_t edma_desc_size(struct edma_desc *edesc)
> > +{
> > +	int i;
> > +	size_t size;
> > +
> > +	if (edesc->absync)
> > +		for (size = i = 0; i < edesc->pset_nr; i++)
> > +			size += (edesc->pset[i].a_b_cnt & 0xffff) *
> > +				(edesc->pset[i].a_b_cnt >> 16) *
> > +				 edesc->pset[i].ccnt;
> > +	else
> > +		size = (edesc->pset[0].a_b_cnt & 0xffff) *
> > +			(edesc->pset[0].a_b_cnt >> 16) +
> > +			(edesc->pset[0].a_b_cnt & 0xffff) *
> > +			(SZ_64K - 1) * edesc->pset[0].ccnt;
> > +
> > +	return size;
> > +}
> > +
> > +/* 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_SUCCESS || !txstate)
> > +		return ret;
> > +
> > +	spin_lock_irqsave(&echan->vchan.lock, flags);
> > +	vdesc = vchan_find_desc(&echan->vchan, cookie);
> > +	if (vdesc) {
> > +		txstate->residue = edma_desc_size(to_edma_desc(&vdesc->tx));
> > +	} else if (echan->edesc && echan->edesc->vdesc.tx.cookie == cookie) {
> > +		struct edma_desc *edesc = echan->edesc;
> > +		txstate->residue = edma_desc_size(edesc);
> > +	} else {
> > +		txstate->residue = 0;
> > +	}
> > +	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;
> > +	int chcnt = 0;
> > +
> > +	for (i = 0; i < EDMA_CHANS; i++) {
> > +		struct edma_chan *echan = &echans[chcnt];
> > +		echan->ch_num = EDMA_CTLR_CHAN(ecc->ctlr, i);
> 
> I couldn't find the definition for EDMA_CTLR_CHAN.

arch/arm/mach-davinci/include/mach/edma.h

> > +		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;
> > +
> > +		chcnt++;
> > +	}
> > +}
> > +
> > +static void edma_dma_init(struct edma_cc *ecc, struct dma_device *dma,
> > +			  struct device *dev)
> > +{
> > +	if (dma_has_cap(DMA_SLAVE, dma->cap_mask))
> > +		dma->device_prep_slave_sg = edma_prep_slave_sg;
> > +
> > +	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_control = edma_control;
> > +	dma->dev = dev;
> > +
> > +	INIT_LIST_HEAD(&dma->channels);
> > +}
> > +
> > +static int __devinit edma_probe(struct platform_device *pdev)
> > +{
> > +	struct edma_cc *ecc;
> > +	int ret;
> > +
> > +	ecc = devm_kzalloc(&pdev->dev, sizeof(*ecc), GFP_KERNEL);
> > +	if (!ecc) {
> > +		dev_err(&pdev->dev, "Can't allocate controller\n");
> > +		ret = -ENOMEM;
> > +		goto err_alloc_ecc;
> > +	}
> > +
> > +	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");
> > +		ret = -EIO;
> > +		goto err_alloc_slot;
> > +	}
> > +
> > +	dma_cap_zero(ecc->dma_slave.cap_mask);
> > +	dma_cap_set(DMA_SLAVE, 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);
> > +err_alloc_slot:
> > +	devm_kfree(&pdev->dev, ecc);
> > +err_alloc_ecc:
> > +	return ret;
> > +}
> > +
> > +static int __devexit 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);
> > +	devm_kfree(dev, ecc);
> > +
> > +	return 0;
> > +}
> > +
> > +static struct platform_driver edma_driver = {
> > +	.probe		= edma_probe,
> > +	.remove		= __devexit_p(edma_remove),
> > +	.driver = {
> > +		.name = "edma-dma-engine",
> > +		.owner = THIS_MODULE,
> 
> I believe you already have plans for DT implementations for this as-well.

Yes, but DT support for the wrapper is not required. See the above
explanation. This works exactly like omap-dma.c. I do have to create
DT bindings to encapsulate the hardware configuration and the plan
is that those will be used to populate the private EDMA API
platform data...and when the private EDMA API goes away (refactored
into drivers/dma/edma.c) then the same DT support will live in the
dmaengine driver.

> > +	},
> > +};
> > +
> > +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 struct platform_device *pdev0, *pdev1;
> > +
> > +static const struct platform_device_info edma_dev_info0 = {
> > +	.name = "edma-dma-engine",
> > +	.id = 0,
> > +	.dma_mask = DMA_BIT_MASK(32),
> > +};
> > +
> > +static const struct platform_device_info edma_dev_info1 = {
> > +	.name = "edma-dma-engine",
> > +	.id = 1,
> > +	.dma_mask = DMA_BIT_MASK(32),
> > +};
> > +
> > +static int edma_init(void)
> > +{
> > +	int ret = platform_driver_register(&edma_driver);
> > +
> > +	if (ret == 0) {
> > +		pdev0 = platform_device_register_full(&edma_dev_info0);
> > +		if (IS_ERR(pdev0)) {
> > +			platform_driver_unregister(&edma_driver);
> > +			ret = PTR_ERR(pdev0);
> > +			goto out;
> > +		}
> > +	}
> > +
> > +	if (EDMA_CTLRS == 2) {
> > +		pdev1 = platform_device_register_full(&edma_dev_info1);
> > +		if (IS_ERR(pdev1)) {
> > +			platform_driver_unregister(&edma_driver);
> > +			platform_device_unregister(pdev0);
> > +			ret = PTR_ERR(pdev1);
> > +		}
> > +	}
> > +
> > +out:
> > +	return ret;
> > +}
> > +subsys_initcall(edma_init);
> > +
> > +static void __exit edma_exit(void)
> > +{
> > +	platform_device_unregister(pdev0);
> > +	if (pdev1)
> > +		platform_device_unregister(pdev1);
> > +	platform_driver_unregister(&edma_driver);
> > +}
> > +module_exit(edma_exit);
> > +
> > +MODULE_AUTHOR("Matt Porter <[email-masked]>");
> > +MODULE_DESCRIPTION("TI EDMA DMA engine driver");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/include/linux/edma.h b/include/linux/edma.h
> > new file mode 100644
> > index 0000000..a1307e7
> > --- /dev/null
> > +++ b/include/linux/edma.h
> > @@ -0,0 +1,29 @@
> > +/*
> > + * 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.
> > + */
> > +#ifndef __LINUX_EDMA_H
> > +#define __LINUX_EDMA_H
> > +
> > +struct dma_chan;
> > +
> > +#if defined(CONFIG_TI_EDMA) || defined(CONFIG_TI_EDMA_MODULE)
> > +bool edma_filter_fn(struct dma_chan *, void *);
> > +#else
> > +static inline bool edma_filter_fn(struct dma_chan *chan, void *param)
> > +{
> > +	return false;
> > +}
> > +#endif
> > +
> > +#endif
> > -- 
> > 1.7.9.5
> > 
> > _______________________________________________
> > Davinci-linux-open-source mailing list
> > Davinci-linux-open-source at linux.davincidsp.com
> > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
> > 
> 
> 
> Regards, 
> Gururaja
> _______________________________________________
> Davinci-linux-open-source mailing list
> Davinci-linux-open-source at linux.davincidsp.com
> http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source