From: "Hebbar, Gururaja" <gururaja.hebbar@ti.com>
To: "Porter, Matt" <mporter@ti.com>,
        "vinod.koul@intel.com" <vinod.koul@intel.com>,
        "cjb@laptop.org" <cjb@laptop.org>,
        "grant.likely@secretlab.ca" <grant.likely@secretlab.ca>
CC: Linux DaVinci Kernel List 
	<davinci-linux-open-source@linux.davincidsp.com>,
        Linux MMC List <linux-mmc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Linux SPI Devel List 
	<spi-devel-general@lists.sourceforge.net>,
        Linux ARM Kernel List <linux-arm-kernel@lists.infradead.org>
Subject: RE: [PATCH v2 1/3] dmaengine: add TI EDMA DMA engine driver
Thread-Topic: [PATCH v2 1/3] dmaengine: add TI EDMA DMA engine driver
Thread-Index: AQHNf8zaD0S4c8VdNkWot3oYaitqOJdlwojQ
Date: Wed, 22 Aug 2012 12:37:18 +0000
Message-ID: <1BAFE6F6C881BF42822005164F1491C33EA65999@DBDE01.ent.ti.com>
References: <1345574589-24757-1-git-send-email-mporter@ti.com>
 <1345574589-24757-2-git-send-email-mporter@ti.com>
In-Reply-To: <1345574589-24757-2-git-send-email-mporter@ti.com>
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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 <mporter@ti.com>
> ---
>  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.

> +
> +/* 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?

> +#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.

> +		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.

> +	},
> +};
> +
> +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 <mporter@ti.com>");
> +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
> 
> _______________________________________________
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> Davinci-linux-open-source@linux.davincidsp.com
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> 


Regards, 
Gururaja
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