drivers/dma/pl330.c - kernel/msm - Gitiles

 /* linux/drivers/dma/pl330.c
  *
  * Copyright (C) 2010 Samsung Electronics Co. Ltd.
  *	Jaswinder Singh <jassi.brar@samsung.com>
  *
  * 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; either version 2 of the License, or
  * (at your option) any later version.
  */

 #include <linux/io.h>
 #include <linux/init.h>
 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/dmaengine.h>
 #include <linux/interrupt.h>
 #include <linux/amba/bus.h>
 #include <linux/amba/pl330.h>

 #define NR_DEFAULT_DESC	16

 enum desc_status {
 	/* In the DMAC pool */
 	FREE,
 	/*
 	 * Allocted to some channel during prep_xxx
 	 * Also may be sitting on the work_list.
 	 */
 	PREP,
 	/*
 	 * Sitting on the work_list and already submitted
 	 * to the PL330 core. Not more than two descriptors
 	 * of a channel can be BUSY at any time.
 	 */
 	BUSY,
 	/*
 	 * Sitting on the channel work_list but xfer done
 	 * by PL330 core
 	 */
 	DONE,
 };

 struct dma_pl330_chan {
 	/* Schedule desc completion */
 	struct tasklet_struct task;

 	/* DMA-Engine Channel */
 	struct dma_chan chan;

 	/* Last completed cookie */
 	dma_cookie_t completed;

 	/* List of to be xfered descriptors */
 	struct list_head work_list;

 	/* Pointer to the DMAC that manages this channel,
 	 * NULL if the channel is available to be acquired.
 	 * As the parent, this DMAC also provides descriptors
 	 * to the channel.
 	 */
 	struct dma_pl330_dmac *dmac;

 	/* To protect channel manipulation */
 	spinlock_t lock;

 	/* Token of a hardware channel thread of PL330 DMAC
 	 * NULL if the channel is available to be acquired.
 	 */
 	void *pl330_chid;
 };

 struct dma_pl330_dmac {
 	struct pl330_info pif;

 	/* DMA-Engine Device */
 	struct dma_device ddma;

 	/* Pool of descriptors available for the DMAC's channels */
 	struct list_head desc_pool;
 	/* To protect desc_pool manipulation */
 	spinlock_t pool_lock;

 	/* Peripheral channels connected to this DMAC */
 	struct dma_pl330_chan *peripherals; /* keep at end */
 };

 struct dma_pl330_desc {
 	/* To attach to a queue as child */
 	struct list_head node;

 	/* Descriptor for the DMA Engine API */
 	struct dma_async_tx_descriptor txd;

 	/* Xfer for PL330 core */
 	struct pl330_xfer px;

 	struct pl330_reqcfg rqcfg;
 	struct pl330_req req;

 	enum desc_status status;

 	/* The channel which currently holds this desc */
 	struct dma_pl330_chan *pchan;
 };

 static inline struct dma_pl330_chan *
 to_pchan(struct dma_chan *ch)
 {
 	if (!ch)
 		return NULL;

 	return container_of(ch, struct dma_pl330_chan, chan);
 }

 static inline struct dma_pl330_desc *
 to_desc(struct dma_async_tx_descriptor *tx)
 {
 	return container_of(tx, struct dma_pl330_desc, txd);
 }

 static inline void free_desc_list(struct list_head *list)
 {
 	struct dma_pl330_dmac *pdmac;
 	struct dma_pl330_desc *desc;
 	struct dma_pl330_chan *pch;
 	unsigned long flags;

 	if (list_empty(list))
 		return;

 	/* Finish off the work list */
 	list_for_each_entry(desc, list, node) {
 		dma_async_tx_callback callback;
 		void *param;

 		/* All desc in a list belong to same channel */
 		pch = desc->pchan;
 		callback = desc->txd.callback;
 		param = desc->txd.callback_param;

 		if (callback)
 			callback(param);

 		desc->pchan = NULL;
 	}

 	pdmac = pch->dmac;

 	spin_lock_irqsave(&pdmac->pool_lock, flags);
 	list_splice_tail_init(list, &pdmac->desc_pool);
 	spin_unlock_irqrestore(&pdmac->pool_lock, flags);
 }

 static inline void fill_queue(struct dma_pl330_chan *pch)
 {
 	struct dma_pl330_desc *desc;
 	int ret;

 	list_for_each_entry(desc, &pch->work_list, node) {

 		/* If already submitted */
 		if (desc->status == BUSY)
 			break;

 		ret = pl330_submit_req(pch->pl330_chid,
 						&desc->req);
 		if (!ret) {
 			desc->status = BUSY;
 			break;
 		} else if (ret == -EAGAIN) {
 			/* QFull or DMAC Dying */
 			break;
 		} else {
 			/* Unacceptable request */
 			desc->status = DONE;
 			dev_err(pch->dmac->pif.dev, "%s:%d Bad Desc(%d)\n",
 					__func__, __LINE__, desc->txd.cookie);
 			tasklet_schedule(&pch->task);
 		}
 	}
 }

 static void pl330_tasklet(unsigned long data)
 {
 	struct dma_pl330_chan *pch = (struct dma_pl330_chan *)data;
 	struct dma_pl330_desc *desc, *_dt;
 	unsigned long flags;
 	LIST_HEAD(list);

 	spin_lock_irqsave(&pch->lock, flags);

 	/* Pick up ripe tomatoes */
 	list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
 		if (desc->status == DONE) {
 			pch->completed = desc->txd.cookie;
 			list_move_tail(&desc->node, &list);
 		}

 	/* Try to submit a req imm. next to the last completed cookie */
 	fill_queue(pch);

 	/* Make sure the PL330 Channel thread is active */
 	pl330_chan_ctrl(pch->pl330_chid, PL330_OP_START);

 	spin_unlock_irqrestore(&pch->lock, flags);

 	free_desc_list(&list);
 }

 static void dma_pl330_rqcb(void *token, enum pl330_op_err err)
 {
 	struct dma_pl330_desc *desc = token;
 	struct dma_pl330_chan *pch = desc->pchan;
 	unsigned long flags;

 	/* If desc aborted */
 	if (!pch)
 		return;

 	spin_lock_irqsave(&pch->lock, flags);

 	desc->status = DONE;

 	spin_unlock_irqrestore(&pch->lock, flags);

 	tasklet_schedule(&pch->task);
 }

 static int pl330_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	struct dma_pl330_dmac *pdmac = pch->dmac;
 	unsigned long flags;

 	spin_lock_irqsave(&pch->lock, flags);

 	pch->completed = chan->cookie = 1;

 	pch->pl330_chid = pl330_request_channel(&pdmac->pif);
 	if (!pch->pl330_chid) {
 		spin_unlock_irqrestore(&pch->lock, flags);
 		return 0;
 	}

 	tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch);

 	spin_unlock_irqrestore(&pch->lock, flags);

 	return 1;
 }

 static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg)
 {
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	struct dma_pl330_desc *desc;
 	unsigned long flags;

 	/* Only supports DMA_TERMINATE_ALL */
 	if (cmd != DMA_TERMINATE_ALL)
 		return -ENXIO;

 	spin_lock_irqsave(&pch->lock, flags);

 	/* FLUSH the PL330 Channel thread */
 	pl330_chan_ctrl(pch->pl330_chid, PL330_OP_FLUSH);

 	/* Mark all desc done */
 	list_for_each_entry(desc, &pch->work_list, node)
 		desc->status = DONE;

 	spin_unlock_irqrestore(&pch->lock, flags);

 	pl330_tasklet((unsigned long) pch);

 	return 0;
 }

 static void pl330_free_chan_resources(struct dma_chan *chan)
 {
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	unsigned long flags;

 	spin_lock_irqsave(&pch->lock, flags);

 	tasklet_kill(&pch->task);

 	pl330_release_channel(pch->pl330_chid);
 	pch->pl330_chid = NULL;

 	spin_unlock_irqrestore(&pch->lock, flags);
 }

 static enum dma_status
 pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 		 struct dma_tx_state *txstate)
 {
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	dma_cookie_t last_done, last_used;
 	int ret;

 	last_done = pch->completed;
 	last_used = chan->cookie;

 	ret = dma_async_is_complete(cookie, last_done, last_used);

 	dma_set_tx_state(txstate, last_done, last_used, 0);

 	return ret;
 }

 static void pl330_issue_pending(struct dma_chan *chan)
 {
 	pl330_tasklet((unsigned long) to_pchan(chan));
 }

 /*
  * We returned the last one of the circular list of descriptor(s)
  * from prep_xxx, so the argument to submit corresponds to the last
  * descriptor of the list.
  */
 static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
 {
 	struct dma_pl330_desc *desc, *last = to_desc(tx);
 	struct dma_pl330_chan *pch = to_pchan(tx->chan);
 	dma_cookie_t cookie;
 	unsigned long flags;

 	spin_lock_irqsave(&pch->lock, flags);

 	/* Assign cookies to all nodes */
 	cookie = tx->chan->cookie;

 	while (!list_empty(&last->node)) {
 		desc = list_entry(last->node.next, struct dma_pl330_desc, node);

 		if (++cookie < 0)
 			cookie = 1;
 		desc->txd.cookie = cookie;

 		list_move_tail(&desc->node, &pch->work_list);
 	}

 	if (++cookie < 0)
 		cookie = 1;
 	last->txd.cookie = cookie;

 	list_add_tail(&last->node, &pch->work_list);

 	tx->chan->cookie = cookie;

 	spin_unlock_irqrestore(&pch->lock, flags);

 	return cookie;
 }

 static inline void _init_desc(struct dma_pl330_desc *desc)
 {
 	desc->pchan = NULL;
 	desc->req.x = &desc->px;
 	desc->req.token = desc;
 	desc->rqcfg.swap = SWAP_NO;
 	desc->rqcfg.privileged = 0;
 	desc->rqcfg.insnaccess = 0;
 	desc->rqcfg.scctl = SCCTRL0;
 	desc->rqcfg.dcctl = DCCTRL0;
 	desc->req.cfg = &desc->rqcfg;
 	desc->req.xfer_cb = dma_pl330_rqcb;
 	desc->txd.tx_submit = pl330_tx_submit;

 	INIT_LIST_HEAD(&desc->node);
 }

 /* Returns the number of descriptors added to the DMAC pool */
 int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count)
 {
 	struct dma_pl330_desc *desc;
 	unsigned long flags;
 	int i;

 	if (!pdmac)
 		return 0;

 	desc = kmalloc(count * sizeof(*desc), flg);
 	if (!desc)
 		return 0;

 	spin_lock_irqsave(&pdmac->pool_lock, flags);

 	for (i = 0; i < count; i++) {
 		_init_desc(&desc[i]);
 		list_add_tail(&desc[i].node, &pdmac->desc_pool);
 	}

 	spin_unlock_irqrestore(&pdmac->pool_lock, flags);

 	return count;
 }

 static struct dma_pl330_desc *
 pluck_desc(struct dma_pl330_dmac *pdmac)
 {
 	struct dma_pl330_desc *desc = NULL;
 	unsigned long flags;

 	if (!pdmac)
 		return NULL;

 	spin_lock_irqsave(&pdmac->pool_lock, flags);

 	if (!list_empty(&pdmac->desc_pool)) {
 		desc = list_entry(pdmac->desc_pool.next,
 				struct dma_pl330_desc, node);

 		list_del_init(&desc->node);

 		desc->status = PREP;
 		desc->txd.callback = NULL;
 	}

 	spin_unlock_irqrestore(&pdmac->pool_lock, flags);

 	return desc;
 }

 static struct dma_pl330_desc *pl330_get_desc(struct dma_pl330_chan *pch)
 {
 	struct dma_pl330_dmac *pdmac = pch->dmac;
 	struct dma_pl330_peri *peri = pch->chan.private;
 	struct dma_pl330_desc *desc;

 	/* Pluck one desc from the pool of DMAC */
 	desc = pluck_desc(pdmac);

 	/* If the DMAC pool is empty, alloc new */
 	if (!desc) {
 		if (!add_desc(pdmac, GFP_ATOMIC, 1))
 			return NULL;

 		/* Try again */
 		desc = pluck_desc(pdmac);
 		if (!desc) {
 			dev_err(pch->dmac->pif.dev,
 				"%s:%d ALERT!\n", __func__, __LINE__);
 			return NULL;
 		}
 	}

 	/* Initialize the descriptor */
 	desc->pchan = pch;
 	desc->txd.cookie = 0;
 	async_tx_ack(&desc->txd);

 	if (peri) {
 		desc->req.rqtype = peri->rqtype;
 		desc->req.peri = peri->peri_id;
 	} else {
 		desc->req.rqtype = MEMTOMEM;
 		desc->req.peri = 0;
 	}

 	dma_async_tx_descriptor_init(&desc->txd, &pch->chan);

 	return desc;
 }

 static inline void fill_px(struct pl330_xfer *px,
 		dma_addr_t dst, dma_addr_t src, size_t len)
 {
 	px->next = NULL;
 	px->bytes = len;
 	px->dst_addr = dst;
 	px->src_addr = src;
 }

 static struct dma_pl330_desc *
 __pl330_prep_dma_memcpy(struct dma_pl330_chan *pch, dma_addr_t dst,
 		dma_addr_t src, size_t len)
 {
 	struct dma_pl330_desc *desc = pl330_get_desc(pch);

 	if (!desc) {
 		dev_err(pch->dmac->pif.dev, "%s:%d Unable to fetch desc\n",
 			__func__, __LINE__);
 		return NULL;
 	}

 	/*
 	 * Ideally we should lookout for reqs bigger than
 	 * those that can be programmed with 256 bytes of
 	 * MC buffer, but considering a req size is seldom
 	 * going to be word-unaligned and more than 200MB,
 	 * we take it easy.
 	 * Also, should the limit is reached we'd rather
 	 * have the platform increase MC buffer size than
 	 * complicating this API driver.
 	 */
 	fill_px(&desc->px, dst, src, len);

 	return desc;
 }

 /* Call after fixing burst size */
 static inline int get_burst_len(struct dma_pl330_desc *desc, size_t len)
 {
 	struct dma_pl330_chan *pch = desc->pchan;
 	struct pl330_info *pi = &pch->dmac->pif;
 	int burst_len;

 	burst_len = pi->pcfg.data_bus_width / 8;
 	burst_len *= pi->pcfg.data_buf_dep;
 	burst_len >>= desc->rqcfg.brst_size;

 	/* src/dst_burst_len can't be more than 16 */
 	if (burst_len > 16)
 		burst_len = 16;

 	while (burst_len > 1) {
 		if (!(len % (burst_len << desc->rqcfg.brst_size)))
 			break;
 		burst_len--;
 	}

 	return burst_len;
 }

 static struct dma_async_tx_descriptor *
 pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
 		dma_addr_t src, size_t len, unsigned long flags)
 {
 	struct dma_pl330_desc *desc;
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	struct dma_pl330_peri *peri = chan->private;
 	struct pl330_info *pi;
 	int burst;

 	if (unlikely(!pch || !len))
 		return NULL;

 	if (peri && peri->rqtype != MEMTOMEM)
 		return NULL;

 	pi = &pch->dmac->pif;

 	desc = __pl330_prep_dma_memcpy(pch, dst, src, len);
 	if (!desc)
 		return NULL;

 	desc->rqcfg.src_inc = 1;
 	desc->rqcfg.dst_inc = 1;

 	/* Select max possible burst size */
 	burst = pi->pcfg.data_bus_width / 8;

 	while (burst > 1) {
 		if (!(len % burst))
 			break;
 		burst /= 2;
 	}

 	desc->rqcfg.brst_size = 0;
 	while (burst != (1 << desc->rqcfg.brst_size))
 		desc->rqcfg.brst_size++;

 	desc->rqcfg.brst_len = get_burst_len(desc, len);

 	desc->txd.flags = flags;

 	return &desc->txd;
 }

 static struct dma_async_tx_descriptor *
 pl330_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 		unsigned int sg_len, enum dma_data_direction direction,
 		unsigned long flg)
 {
 	struct dma_pl330_desc *first, *desc = NULL;
 	struct dma_pl330_chan *pch = to_pchan(chan);
 	struct dma_pl330_peri *peri = chan->private;
 	struct scatterlist *sg;
 	unsigned long flags;
 	int i, burst_size;
 	dma_addr_t addr;

 	if (unlikely(!pch || !sgl || !sg_len || !peri))
 		return NULL;

 	/* Make sure the direction is consistent */
 	if ((direction == DMA_TO_DEVICE &&
 				peri->rqtype != MEMTODEV) ||
 			(direction == DMA_FROM_DEVICE &&
 				peri->rqtype != DEVTOMEM)) {
 		dev_err(pch->dmac->pif.dev, "%s:%d Invalid Direction\n",
 				__func__, __LINE__);
 		return NULL;
 	}

 	addr = peri->fifo_addr;
 	burst_size = peri->burst_sz;

 	first = NULL;

 	for_each_sg(sgl, sg, sg_len, i) {

 		desc = pl330_get_desc(pch);
 		if (!desc) {
 			struct dma_pl330_dmac *pdmac = pch->dmac;

 			dev_err(pch->dmac->pif.dev,
 				"%s:%d Unable to fetch desc\n",
 				__func__, __LINE__);
 			if (!first)
 				return NULL;

 			spin_lock_irqsave(&pdmac->pool_lock, flags);

 			while (!list_empty(&first->node)) {
 				desc = list_entry(first->node.next,
 						struct dma_pl330_desc, node);
 				list_move_tail(&desc->node, &pdmac->desc_pool);
 			}

 			list_move_tail(&first->node, &pdmac->desc_pool);

 			spin_unlock_irqrestore(&pdmac->pool_lock, flags);

 			return NULL;
 		}

 		if (!first)
 			first = desc;
 		else
 			list_add_tail(&desc->node, &first->node);

 		if (direction == DMA_TO_DEVICE) {
 			desc->rqcfg.src_inc = 1;
 			desc->rqcfg.dst_inc = 0;
 			fill_px(&desc->px,
 				addr, sg_dma_address(sg), sg_dma_len(sg));
 		} else {
 			desc->rqcfg.src_inc = 0;
 			desc->rqcfg.dst_inc = 1;
 			fill_px(&desc->px,
 				sg_dma_address(sg), addr, sg_dma_len(sg));
 		}

 		desc->rqcfg.brst_size = burst_size;
 		desc->rqcfg.brst_len = 1;
 	}

 	/* Return the last desc in the chain */
 	desc->txd.flags = flg;
 	return &desc->txd;
 }

 static irqreturn_t pl330_irq_handler(int irq, void *data)
 {
 	if (pl330_update(data))
 		return IRQ_HANDLED;
 	else
 		return IRQ_NONE;
 }

 static int __devinit
 pl330_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct dma_pl330_platdata *pdat;
 	struct dma_pl330_dmac *pdmac;
 	struct dma_pl330_chan *pch;
 	struct pl330_info *pi;
 	struct dma_device *pd;
 	struct resource *res;
 	int i, ret, irq;
 	int num_chan;

 	pdat = adev->dev.platform_data;

 	/* Allocate a new DMAC and its Channels */
 	pdmac = kzalloc(sizeof(*pdmac), GFP_KERNEL);
 	if (!pdmac) {
 		dev_err(&adev->dev, "unable to allocate mem\n");
 		return -ENOMEM;
 	}

 	pi = &pdmac->pif;
 	pi->dev = &adev->dev;
 	pi->pl330_data = NULL;
 	pi->mcbufsz = pdat ? pdat->mcbuf_sz : 0;

 	res = &adev->res;
 	request_mem_region(res->start, resource_size(res), "dma-pl330");

 	pi->base = ioremap(res->start, resource_size(res));
 	if (!pi->base) {
 		ret = -ENXIO;
 		goto probe_err1;
 	}

 	irq = adev->irq[0];
 	ret = request_irq(irq, pl330_irq_handler, 0,
 			dev_name(&adev->dev), pi);
 	if (ret)
 		goto probe_err2;

 	ret = pl330_add(pi);
 	if (ret)
 		goto probe_err3;

 	INIT_LIST_HEAD(&pdmac->desc_pool);
 	spin_lock_init(&pdmac->pool_lock);

 	/* Create a descriptor pool of default size */
 	if (!add_desc(pdmac, GFP_KERNEL, NR_DEFAULT_DESC))
 		dev_warn(&adev->dev, "unable to allocate desc\n");

 	pd = &pdmac->ddma;
 	INIT_LIST_HEAD(&pd->channels);

 	/* Initialize channel parameters */
 	num_chan = max(pdat ? pdat->nr_valid_peri : 0, (u8)pi->pcfg.num_chan);
 	pdmac->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);

 	for (i = 0; i < num_chan; i++) {
 		pch = &pdmac->peripherals[i];
 		if (pdat) {
 			struct dma_pl330_peri *peri = &pdat->peri[i];

 			switch (peri->rqtype) {
 			case MEMTOMEM:
 				dma_cap_set(DMA_MEMCPY, pd->cap_mask);
 				break;
 			case MEMTODEV:
 			case DEVTOMEM:
 				dma_cap_set(DMA_SLAVE, pd->cap_mask);
 				break;
 			default:
 				dev_err(&adev->dev, "DEVTODEV Not Supported\n");
 				continue;
 			}
 			pch->chan.private = peri;
 		} else {
 			dma_cap_set(DMA_MEMCPY, pd->cap_mask);
 			pch->chan.private = NULL;
 		}

 		INIT_LIST_HEAD(&pch->work_list);
 		spin_lock_init(&pch->lock);
 		pch->pl330_chid = NULL;
 		pch->chan.device = pd;
 		pch->chan.chan_id = i;
 		pch->dmac = pdmac;

 		/* Add the channel to the DMAC list */
 		pd->chancnt++;
 		list_add_tail(&pch->chan.device_node, &pd->channels);
 	}

 	pd->dev = &adev->dev;

 	pd->device_alloc_chan_resources = pl330_alloc_chan_resources;
 	pd->device_free_chan_resources = pl330_free_chan_resources;
 	pd->device_prep_dma_memcpy = pl330_prep_dma_memcpy;
 	pd->device_tx_status = pl330_tx_status;
 	pd->device_prep_slave_sg = pl330_prep_slave_sg;
 	pd->device_control = pl330_control;
 	pd->device_issue_pending = pl330_issue_pending;

 	ret = dma_async_device_register(pd);
 	if (ret) {
 		dev_err(&adev->dev, "unable to register DMAC\n");
 		goto probe_err4;
 	}

 	amba_set_drvdata(adev, pdmac);

 	dev_info(&adev->dev,
 		"Loaded driver for PL330 DMAC-%d\n", adev->periphid);
 	dev_info(&adev->dev,
 		"\tDBUFF-%ux%ubytes Num_Chans-%u Num_Peri-%u Num_Events-%u\n",
 		pi->pcfg.data_buf_dep,
 		pi->pcfg.data_bus_width / 8, pi->pcfg.num_chan,
 		pi->pcfg.num_peri, pi->pcfg.num_events);

 	return 0;

 probe_err4:
 	pl330_del(pi);
 probe_err3:
 	free_irq(irq, pi);
 probe_err2:
 	iounmap(pi->base);
 probe_err1:
 	release_mem_region(res->start, resource_size(res));
 	kfree(pdmac);

 	return ret;
 }

 static int __devexit pl330_remove(struct amba_device *adev)
 {
 	struct dma_pl330_dmac *pdmac = amba_get_drvdata(adev);
 	struct dma_pl330_chan *pch, *_p;
 	struct pl330_info *pi;
 	struct resource *res;
 	int irq;

 	if (!pdmac)
 		return 0;

 	amba_set_drvdata(adev, NULL);

 	/* Idle the DMAC */
 	list_for_each_entry_safe(pch, _p, &pdmac->ddma.channels,
 			chan.device_node) {

 		/* Remove the channel */
 		list_del(&pch->chan.device_node);

 		/* Flush the channel */
 		pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0);
 		pl330_free_chan_resources(&pch->chan);
 	}

 	pi = &pdmac->pif;

 	pl330_del(pi);

 	irq = adev->irq[0];
 	free_irq(irq, pi);

 	iounmap(pi->base);

 	res = &adev->res;
 	release_mem_region(res->start, resource_size(res));

 	kfree(pdmac);

 	return 0;
 }

 static struct amba_id pl330_ids[] = {
 	{
 		.id	= 0x00041330,
 		.mask	= 0x000fffff,
 	},
 	{ 0, 0 },
 };

 static struct amba_driver pl330_driver = {
 	.drv = {
 		.owner = THIS_MODULE,
 		.name = "dma-pl330",
 	},
 	.id_table = pl330_ids,
 	.probe = pl330_probe,
 	.remove = pl330_remove,
 };

 static int __init pl330_init(void)
 {
 	return amba_driver_register(&pl330_driver);
 }
 module_init(pl330_init);

 static void __exit pl330_exit(void)
 {
 	amba_driver_unregister(&pl330_driver);
 	return;
 }
 module_exit(pl330_exit);

 MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
 MODULE_DESCRIPTION("API Driver for PL330 DMAC");
 MODULE_LICENSE("GPL");
	/* linux/drivers/dma/pl330.c
	*
	* Copyright (C) 2010 Samsung Electronics Co. Ltd.
	* Jaswinder Singh <jassi.brar@samsung.com>
	*
	* 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; either version 2 of the License, or
	* (at your option) any later version.
	*/

	#include <linux/io.h>
	#include <linux/init.h>
	#include <linux/slab.h>
	#include <linux/module.h>
	#include <linux/dmaengine.h>
	#include <linux/interrupt.h>
	#include <linux/amba/bus.h>
	#include <linux/amba/pl330.h>

	#define NR_DEFAULT_DESC 16

	enum desc_status {
	/* In the DMAC pool */
	FREE,
	/*
	* Allocted to some channel during prep_xxx
	* Also may be sitting on the work_list.
	*/
	PREP,
	/*
	* Sitting on the work_list and already submitted
	* to the PL330 core. Not more than two descriptors
	* of a channel can be BUSY at any time.
	*/
	BUSY,
	/*
	* Sitting on the channel work_list but xfer done
	* by PL330 core
	*/
	DONE,
	};

	struct dma_pl330_chan {
	/* Schedule desc completion */
	struct tasklet_struct task;

	/* DMA-Engine Channel */
	struct dma_chan chan;

	/* Last completed cookie */
	dma_cookie_t completed;

	/* List of to be xfered descriptors */
	struct list_head work_list;

	/* Pointer to the DMAC that manages this channel,
	* NULL if the channel is available to be acquired.
	* As the parent, this DMAC also provides descriptors
	* to the channel.
	*/
	struct dma_pl330_dmac *dmac;

	/* To protect channel manipulation */
	spinlock_t lock;

	/* Token of a hardware channel thread of PL330 DMAC
	* NULL if the channel is available to be acquired.
	*/
	void *pl330_chid;
	};

	struct dma_pl330_dmac {
	struct pl330_info pif;

	/* DMA-Engine Device */
	struct dma_device ddma;

	/* Pool of descriptors available for the DMAC's channels */
	struct list_head desc_pool;
	/* To protect desc_pool manipulation */
	spinlock_t pool_lock;

	/* Peripheral channels connected to this DMAC */
	struct dma_pl330_chan peripherals; / keep at end */
	};

	struct dma_pl330_desc {
	/* To attach to a queue as child */
	struct list_head node;

	/* Descriptor for the DMA Engine API */
	struct dma_async_tx_descriptor txd;

	/* Xfer for PL330 core */
	struct pl330_xfer px;

	struct pl330_reqcfg rqcfg;
	struct pl330_req req;

	enum desc_status status;

	/* The channel which currently holds this desc */
	struct dma_pl330_chan *pchan;
	};

	static inline struct dma_pl330_chan *
	to_pchan(struct dma_chan *ch)
	{
	if (!ch)
	return NULL;

	return container_of(ch, struct dma_pl330_chan, chan);
	}

	static inline struct dma_pl330_desc *
	to_desc(struct dma_async_tx_descriptor *tx)
	{
	return container_of(tx, struct dma_pl330_desc, txd);
	}

	static inline void free_desc_list(struct list_head *list)
	{
	struct dma_pl330_dmac *pdmac;
	struct dma_pl330_desc *desc;
	struct dma_pl330_chan *pch;
	unsigned long flags;

	if (list_empty(list))
	return;

	/* Finish off the work list */
	list_for_each_entry(desc, list, node) {
	dma_async_tx_callback callback;
	void *param;

	/* All desc in a list belong to same channel */
	pch = desc->pchan;
	callback = desc->txd.callback;
	param = desc->txd.callback_param;

	if (callback)
	callback(param);

	desc->pchan = NULL;
	}

	pdmac = pch->dmac;

	spin_lock_irqsave(&pdmac->pool_lock, flags);
	list_splice_tail_init(list, &pdmac->desc_pool);
	spin_unlock_irqrestore(&pdmac->pool_lock, flags);
	}

	static inline void fill_queue(struct dma_pl330_chan *pch)
	{
	struct dma_pl330_desc *desc;
	int ret;

	list_for_each_entry(desc, &pch->work_list, node) {

	/* If already submitted */
	if (desc->status == BUSY)
	break;

	ret = pl330_submit_req(pch->pl330_chid,
	&desc->req);
	if (!ret) {
	desc->status = BUSY;
	break;
	} else if (ret == -EAGAIN) {
	/* QFull or DMAC Dying */
	break;
	} else {
	/* Unacceptable request */
	desc->status = DONE;
	dev_err(pch->dmac->pif.dev, "%s:%d Bad Desc(%d)\n",
	__func__, __LINE__, desc->txd.cookie);
	tasklet_schedule(&pch->task);
	}
	}
	}

	static void pl330_tasklet(unsigned long data)
	{
	struct dma_pl330_chan pch = (struct dma_pl330_chan )data;
	struct dma_pl330_desc desc, _dt;
	unsigned long flags;
	LIST_HEAD(list);

	spin_lock_irqsave(&pch->lock, flags);

	/* Pick up ripe tomatoes */
	list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
	if (desc->status == DONE) {
	pch->completed = desc->txd.cookie;
	list_move_tail(&desc->node, &list);
	}

	/* Try to submit a req imm. next to the last completed cookie */
	fill_queue(pch);

	/* Make sure the PL330 Channel thread is active */
	pl330_chan_ctrl(pch->pl330_chid, PL330_OP_START);

	spin_unlock_irqrestore(&pch->lock, flags);

	free_desc_list(&list);
	}

	static void dma_pl330_rqcb(void *token, enum pl330_op_err err)
	{
	struct dma_pl330_desc *desc = token;
	struct dma_pl330_chan *pch = desc->pchan;
	unsigned long flags;

	/* If desc aborted */
	if (!pch)
	return;

	spin_lock_irqsave(&pch->lock, flags);

	desc->status = DONE;

	spin_unlock_irqrestore(&pch->lock, flags);

	tasklet_schedule(&pch->task);
	}

	static int pl330_alloc_chan_resources(struct dma_chan *chan)
	{
	struct dma_pl330_chan *pch = to_pchan(chan);
	struct dma_pl330_dmac *pdmac = pch->dmac;
	unsigned long flags;

	spin_lock_irqsave(&pch->lock, flags);

	pch->completed = chan->cookie = 1;

	pch->pl330_chid = pl330_request_channel(&pdmac->pif);
	if (!pch->pl330_chid) {
	spin_unlock_irqrestore(&pch->lock, flags);
	return 0;
	}

	tasklet_init(&pch->task, pl330_tasklet, (unsigned long) pch);

	spin_unlock_irqrestore(&pch->lock, flags);

	return 1;
	}

	static int pl330_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, unsigned long arg)
	{
	struct dma_pl330_chan *pch = to_pchan(chan);
	struct dma_pl330_desc *desc;
	unsigned long flags;

	/* Only supports DMA_TERMINATE_ALL */
	if (cmd != DMA_TERMINATE_ALL)
	return -ENXIO;

	spin_lock_irqsave(&pch->lock, flags);

	/* FLUSH the PL330 Channel thread */
	pl330_chan_ctrl(pch->pl330_chid, PL330_OP_FLUSH);

	/* Mark all desc done */
	list_for_each_entry(desc, &pch->work_list, node)
	desc->status = DONE;

	spin_unlock_irqrestore(&pch->lock, flags);

	pl330_tasklet((unsigned long) pch);

	return 0;
	}

	static void pl330_free_chan_resources(struct dma_chan *chan)
	{
	struct dma_pl330_chan *pch = to_pchan(chan);
	unsigned long flags;

	spin_lock_irqsave(&pch->lock, flags);

	tasklet_kill(&pch->task);

	pl330_release_channel(pch->pl330_chid);
	pch->pl330_chid = NULL;

	spin_unlock_irqrestore(&pch->lock, flags);
	}

	static enum dma_status
	pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
	struct dma_tx_state *txstate)
	{
	struct dma_pl330_chan *pch = to_pchan(chan);
	dma_cookie_t last_done, last_used;
	int ret;

	last_done = pch->completed;
	last_used = chan->cookie;

	ret = dma_async_is_complete(cookie, last_done, last_used);

	dma_set_tx_state(txstate, last_done, last_used, 0);

	return ret;
	}

	static void pl330_issue_pending(struct dma_chan *chan)
	{
	pl330_tasklet((unsigned long) to_pchan(chan));
	}

	/*
	* We returned the last one of the circular list of descriptor(s)
	* from prep_xxx, so the argument to submit corresponds to the last
	* descriptor of the list.
	*/
	static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
	{
	struct dma_pl330_desc desc, last = to_desc(tx);
	struct dma_pl330_chan *pch = to_pchan(tx->chan);
	dma_cookie_t cookie;
	unsigned long flags;

	spin_lock_irqsave(&pch->lock, flags);

	/* Assign cookies to all nodes */
	cookie = tx->chan->cookie;

	while (!list_empty(&last->node)) {
	desc = list_entry(last->node.next, struct dma_pl330_desc, node);

	if (++cookie < 0)
	cookie = 1;
	desc->txd.cookie = cookie;

	list_move_tail(&desc->node, &pch->work_list);
	}

	if (++cookie < 0)
	cookie = 1;
	last->txd.cookie = cookie;

	list_add_tail(&last->node, &pch->work_list);

	tx->chan->cookie = cookie;

	spin_unlock_irqrestore(&pch->lock, flags);

	return cookie;
	}

	static inline void _init_desc(struct dma_pl330_desc *desc)
	{
	desc->pchan = NULL;
	desc->req.x = &desc->px;
	desc->req.token = desc;
	desc->rqcfg.swap = SWAP_NO;
	desc->rqcfg.privileged = 0;
	desc->rqcfg.insnaccess = 0;
	desc->rqcfg.scctl = SCCTRL0;
	desc->rqcfg.dcctl = DCCTRL0;
	desc->req.cfg = &desc->rqcfg;
	desc->req.xfer_cb = dma_pl330_rqcb;
	desc->txd.tx_submit = pl330_tx_submit;

	INIT_LIST_HEAD(&desc->node);
	}

	/* Returns the number of descriptors added to the DMAC pool */
	int add_desc(struct dma_pl330_dmac *pdmac, gfp_t flg, int count)
	{
	struct dma_pl330_desc *desc;
	unsigned long flags;
	int i;

	if (!pdmac)
	return 0;

	desc = kmalloc(count * sizeof(*desc), flg);
	if (!desc)
	return 0;

	spin_lock_irqsave(&pdmac->pool_lock, flags);

	for (i = 0; i < count; i++) {
	_init_desc(&desc[i]);
	list_add_tail(&desc[i].node, &pdmac->desc_pool);
	}

	spin_unlock_irqrestore(&pdmac->pool_lock, flags);

	return count;
	}

	static struct dma_pl330_desc *
	pluck_desc(struct dma_pl330_dmac *pdmac)
	{
	struct dma_pl330_desc *desc = NULL;
	unsigned long flags;

	if (!pdmac)
	return NULL;

	spin_lock_irqsave(&pdmac->pool_lock, flags);

	if (!list_empty(&pdmac->desc_pool)) {
	desc = list_entry(pdmac->desc_pool.next,
	struct dma_pl330_desc, node);

	list_del_init(&desc->node);

	desc->status = PREP;
	desc->txd.callback = NULL;
	}

	spin_unlock_irqrestore(&pdmac->pool_lock, flags);

	return desc;
	}

	static struct dma_pl330_desc pl330_get_desc(struct dma_pl330_chan pch)
	{
	struct dma_pl330_dmac *pdmac = pch->dmac;
	struct dma_pl330_peri *peri = pch->chan.private;
	struct dma_pl330_desc *desc;

	/* Pluck one desc from the pool of DMAC */
	desc = pluck_desc(pdmac);

	/* If the DMAC pool is empty, alloc new */
	if (!desc) {
	if (!add_desc(pdmac, GFP_ATOMIC, 1))
	return NULL;

	/* Try again */
	desc = pluck_desc(pdmac);
	if (!desc) {
	dev_err(pch->dmac->pif.dev,
	"%s:%d ALERT!\n", __func__, __LINE__);
	return NULL;
	}
	}

	/* Initialize the descriptor */
	desc->pchan = pch;
	desc->txd.cookie = 0;
	async_tx_ack(&desc->txd);

	if (peri) {
	desc->req.rqtype = peri->rqtype;
	desc->req.peri = peri->peri_id;
	} else {
	desc->req.rqtype = MEMTOMEM;
	desc->req.peri = 0;
	}

	dma_async_tx_descriptor_init(&desc->txd, &pch->chan);

	return desc;
	}

	static inline void fill_px(struct pl330_xfer *px,
	dma_addr_t dst, dma_addr_t src, size_t len)
	{
	px->next = NULL;
	px->bytes = len;
	px->dst_addr = dst;
	px->src_addr = src;
	}

	static struct dma_pl330_desc *
	__pl330_prep_dma_memcpy(struct dma_pl330_chan *pch, dma_addr_t dst,
	dma_addr_t src, size_t len)
	{
	struct dma_pl330_desc *desc = pl330_get_desc(pch);

	if (!desc) {
	dev_err(pch->dmac->pif.dev, "%s:%d Unable to fetch desc\n",
	__func__, __LINE__);
	return NULL;
	}

	/*
	* Ideally we should lookout for reqs bigger than
	* those that can be programmed with 256 bytes of
	* MC buffer, but considering a req size is seldom
	* going to be word-unaligned and more than 200MB,
	* we take it easy.
	* Also, should the limit is reached we'd rather
	* have the platform increase MC buffer size than
	* complicating this API driver.
	*/
	fill_px(&desc->px, dst, src, len);

	return desc;
	}

	/* Call after fixing burst size */
	static inline int get_burst_len(struct dma_pl330_desc *desc, size_t len)
	{
	struct dma_pl330_chan *pch = desc->pchan;
	struct pl330_info *pi = &pch->dmac->pif;
	int burst_len;

	burst_len = pi->pcfg.data_bus_width / 8;
	burst_len *= pi->pcfg.data_buf_dep;
	burst_len >>= desc->rqcfg.brst_size;

	/* src/dst_burst_len can't be more than 16 */
	if (burst_len > 16)
	burst_len = 16;

	while (burst_len > 1) {
	if (!(len % (burst_len << desc->rqcfg.brst_size)))
	break;
	burst_len--;
	}

	return burst_len;
	}

	static struct dma_async_tx_descriptor *
	pl330_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dst,
	dma_addr_t src, size_t len, unsigned long flags)
	{
	struct dma_pl330_desc *desc;
	struct dma_pl330_chan *pch = to_pchan(chan);
	struct dma_pl330_peri *peri = chan->private;
	struct pl330_info *pi;
	int burst;

	if (unlikely(!pch \|\| !len))
	return NULL;

	if (peri && peri->rqtype != MEMTOMEM)
	return NULL;

	pi = &pch->dmac->pif;

	desc = __pl330_prep_dma_memcpy(pch, dst, src, len);
	if (!desc)
	return NULL;

	desc->rqcfg.src_inc = 1;
	desc->rqcfg.dst_inc = 1;

	/* Select max possible burst size */
	burst = pi->pcfg.data_bus_width / 8;

	while (burst > 1) {
	if (!(len % burst))
	break;
	burst /= 2;
	}

	desc->rqcfg.brst_size = 0;
	while (burst != (1 << desc->rqcfg.brst_size))
	desc->rqcfg.brst_size++;

	desc->rqcfg.brst_len = get_burst_len(desc, len);

	desc->txd.flags = flags;

	return &desc->txd;
	}

	static struct dma_async_tx_descriptor *
	pl330_prep_slave_sg(struct dma_chan chan, struct scatterlist sgl,
	unsigned int sg_len, enum dma_data_direction direction,
	unsigned long flg)
	{
	struct dma_pl330_desc first, desc = NULL;
	struct dma_pl330_chan *pch = to_pchan(chan);
	struct dma_pl330_peri *peri = chan->private;
	struct scatterlist *sg;
	unsigned long flags;
	int i, burst_size;
	dma_addr_t addr;

	if (unlikely(!pch \|\| !sgl \|\| !sg_len \|\| !peri))
	return NULL;

	/* Make sure the direction is consistent */
	if ((direction == DMA_TO_DEVICE &&
	peri->rqtype != MEMTODEV) \|\|
	(direction == DMA_FROM_DEVICE &&
	peri->rqtype != DEVTOMEM)) {
	dev_err(pch->dmac->pif.dev, "%s:%d Invalid Direction\n",
	__func__, __LINE__);
	return NULL;
	}

	addr = peri->fifo_addr;
	burst_size = peri->burst_sz;

	first = NULL;

	for_each_sg(sgl, sg, sg_len, i) {

	desc = pl330_get_desc(pch);
	if (!desc) {
	struct dma_pl330_dmac *pdmac = pch->dmac;

	dev_err(pch->dmac->pif.dev,
	"%s:%d Unable to fetch desc\n",
	__func__, __LINE__);
	if (!first)
	return NULL;

	spin_lock_irqsave(&pdmac->pool_lock, flags);

	while (!list_empty(&first->node)) {
	desc = list_entry(first->node.next,
	struct dma_pl330_desc, node);
	list_move_tail(&desc->node, &pdmac->desc_pool);
	}

	list_move_tail(&first->node, &pdmac->desc_pool);

	spin_unlock_irqrestore(&pdmac->pool_lock, flags);

	return NULL;
	}

	if (!first)
	first = desc;
	else
	list_add_tail(&desc->node, &first->node);

	if (direction == DMA_TO_DEVICE) {
	desc->rqcfg.src_inc = 1;
	desc->rqcfg.dst_inc = 0;
	fill_px(&desc->px,
	addr, sg_dma_address(sg), sg_dma_len(sg));
	} else {
	desc->rqcfg.src_inc = 0;
	desc->rqcfg.dst_inc = 1;
	fill_px(&desc->px,
	sg_dma_address(sg), addr, sg_dma_len(sg));
	}

	desc->rqcfg.brst_size = burst_size;
	desc->rqcfg.brst_len = 1;
	}

	/* Return the last desc in the chain */
	desc->txd.flags = flg;
	return &desc->txd;
	}

	static irqreturn_t pl330_irq_handler(int irq, void *data)
	{
	if (pl330_update(data))
	return IRQ_HANDLED;
	else
	return IRQ_NONE;
	}

	static int __devinit
	pl330_probe(struct amba_device adev, const struct amba_id id)
	{
	struct dma_pl330_platdata *pdat;
	struct dma_pl330_dmac *pdmac;
	struct dma_pl330_chan *pch;
	struct pl330_info *pi;
	struct dma_device *pd;
	struct resource *res;
	int i, ret, irq;
	int num_chan;

	pdat = adev->dev.platform_data;

	/* Allocate a new DMAC and its Channels */
	pdmac = kzalloc(sizeof(*pdmac), GFP_KERNEL);
	if (!pdmac) {
	dev_err(&adev->dev, "unable to allocate mem\n");
	return -ENOMEM;
	}

	pi = &pdmac->pif;
	pi->dev = &adev->dev;
	pi->pl330_data = NULL;
	pi->mcbufsz = pdat ? pdat->mcbuf_sz : 0;

	res = &adev->res;
	request_mem_region(res->start, resource_size(res), "dma-pl330");

	pi->base = ioremap(res->start, resource_size(res));
	if (!pi->base) {
	ret = -ENXIO;
	goto probe_err1;
	}

	irq = adev->irq[0];
	ret = request_irq(irq, pl330_irq_handler, 0,
	dev_name(&adev->dev), pi);
	if (ret)
	goto probe_err2;

	ret = pl330_add(pi);
	if (ret)
	goto probe_err3;

	INIT_LIST_HEAD(&pdmac->desc_pool);
	spin_lock_init(&pdmac->pool_lock);

	/* Create a descriptor pool of default size */
	if (!add_desc(pdmac, GFP_KERNEL, NR_DEFAULT_DESC))
	dev_warn(&adev->dev, "unable to allocate desc\n");

	pd = &pdmac->ddma;
	INIT_LIST_HEAD(&pd->channels);

	/* Initialize channel parameters */
	num_chan = max(pdat ? pdat->nr_valid_peri : 0, (u8)pi->pcfg.num_chan);
	pdmac->peripherals = kzalloc(num_chan * sizeof(*pch), GFP_KERNEL);

	for (i = 0; i < num_chan; i++) {
	pch = &pdmac->peripherals[i];
	if (pdat) {
	struct dma_pl330_peri *peri = &pdat->peri[i];

	switch (peri->rqtype) {
	case MEMTOMEM:
	dma_cap_set(DMA_MEMCPY, pd->cap_mask);
	break;
	case MEMTODEV:
	case DEVTOMEM:
	dma_cap_set(DMA_SLAVE, pd->cap_mask);
	break;
	default:
	dev_err(&adev->dev, "DEVTODEV Not Supported\n");
	continue;
	}
	pch->chan.private = peri;
	} else {
	dma_cap_set(DMA_MEMCPY, pd->cap_mask);
	pch->chan.private = NULL;
	}

	INIT_LIST_HEAD(&pch->work_list);
	spin_lock_init(&pch->lock);
	pch->pl330_chid = NULL;
	pch->chan.device = pd;
	pch->chan.chan_id = i;
	pch->dmac = pdmac;

	/* Add the channel to the DMAC list */
	pd->chancnt++;
	list_add_tail(&pch->chan.device_node, &pd->channels);
	}

	pd->dev = &adev->dev;

	pd->device_alloc_chan_resources = pl330_alloc_chan_resources;
	pd->device_free_chan_resources = pl330_free_chan_resources;
	pd->device_prep_dma_memcpy = pl330_prep_dma_memcpy;
	pd->device_tx_status = pl330_tx_status;
	pd->device_prep_slave_sg = pl330_prep_slave_sg;
	pd->device_control = pl330_control;
	pd->device_issue_pending = pl330_issue_pending;

	ret = dma_async_device_register(pd);
	if (ret) {
	dev_err(&adev->dev, "unable to register DMAC\n");
	goto probe_err4;
	}

	amba_set_drvdata(adev, pdmac);

	dev_info(&adev->dev,
	"Loaded driver for PL330 DMAC-%d\n", adev->periphid);
	dev_info(&adev->dev,
	"\tDBUFF-%ux%ubytes Num_Chans-%u Num_Peri-%u Num_Events-%u\n",
	pi->pcfg.data_buf_dep,
	pi->pcfg.data_bus_width / 8, pi->pcfg.num_chan,
	pi->pcfg.num_peri, pi->pcfg.num_events);

	return 0;

	probe_err4:
	pl330_del(pi);
	probe_err3:
	free_irq(irq, pi);
	probe_err2:
	iounmap(pi->base);
	probe_err1:
	release_mem_region(res->start, resource_size(res));
	kfree(pdmac);

	return ret;
	}

	static int __devexit pl330_remove(struct amba_device *adev)
	{
	struct dma_pl330_dmac *pdmac = amba_get_drvdata(adev);
	struct dma_pl330_chan pch, _p;
	struct pl330_info *pi;
	struct resource *res;
	int irq;

	if (!pdmac)
	return 0;

	amba_set_drvdata(adev, NULL);

	/* Idle the DMAC */
	list_for_each_entry_safe(pch, _p, &pdmac->ddma.channels,
	chan.device_node) {

	/* Remove the channel */
	list_del(&pch->chan.device_node);

	/* Flush the channel */
	pl330_control(&pch->chan, DMA_TERMINATE_ALL, 0);
	pl330_free_chan_resources(&pch->chan);
	}

	pi = &pdmac->pif;

	pl330_del(pi);

	irq = adev->irq[0];
	free_irq(irq, pi);

	iounmap(pi->base);

	res = &adev->res;
	release_mem_region(res->start, resource_size(res));

	kfree(pdmac);

	return 0;
	}

	static struct amba_id pl330_ids[] = {
	{
	.id = 0x00041330,
	.mask = 0x000fffff,
	},
	{ 0, 0 },
	};

	static struct amba_driver pl330_driver = {
	.drv = {
	.owner = THIS_MODULE,
	.name = "dma-pl330",
	},
	.id_table = pl330_ids,
	.probe = pl330_probe,
	.remove = pl330_remove,
	};

	static int __init pl330_init(void)
	{
	return amba_driver_register(&pl330_driver);
	}
	module_init(pl330_init);

	static void __exit pl330_exit(void)
	{
	amba_driver_unregister(&pl330_driver);
	return;
	}
	module_exit(pl330_exit);

	MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
	MODULE_DESCRIPTION("API Driver for PL330 DMAC");
	MODULE_LICENSE("GPL");