dma: dw: split driver to library part and platform code

To simplify the driver development let's split driver to library and platform
code parts. It helps us to add PCI driver in future.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[Fixed compile error and few checkpatch issues]
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 1730 insertions, 0 deletions

diff --git a/drivers/dma/dw/core.c b/drivers/dma/dw/core.c
new file mode 100644
index 000000000000..eea479c12173
--- /dev/null
+++ b/drivers/dma/dw/core.c
@@ -0,0 +1,1730 @@
+/*
+ * Core driver for the Synopsys DesignWare DMA Controller
+ *
+ * Copyright (C) 2007-2008 Atmel Corporation
+ * Copyright (C) 2010-2011 ST Microelectronics
+ * Copyright (C) 2013 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include "../dmaengine.h"
+#include "internal.h"
+
+/*
+ * This supports the Synopsys "DesignWare AHB Central DMA Controller",
+ * (DW_ahb_dmac) which is used with various AMBA 2.0 systems (not all
+ * of which use ARM any more).  See the "Databook" from Synopsys for
+ * information beyond what licensees probably provide.
+ *
+ * The driver has currently been tested only with the Atmel AT32AP7000,
+ * which does not support descriptor writeback.
+ */
+
+static inline void dwc_set_masters(struct dw_dma_chan *dwc)
+{
+	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+	struct dw_dma_slave *dws = dwc->chan.private;
+	unsigned char mmax = dw->nr_masters - 1;
+
+	if (dwc->request_line == ~0) {
+		dwc->src_master = min_t(unsigned char, mmax, dwc_get_sms(dws));
+		dwc->dst_master = min_t(unsigned char, mmax, dwc_get_dms(dws));
+	}
+}
+
+#define DWC_DEFAULT_CTLLO(_chan) ({				\
+		struct dw_dma_chan *_dwc = to_dw_dma_chan(_chan);	\
+		struct dma_slave_config	*_sconfig = &_dwc->dma_sconfig;	\
+		bool _is_slave = is_slave_direction(_dwc->direction);	\
+		u8 _smsize = _is_slave ? _sconfig->src_maxburst :	\
+			DW_DMA_MSIZE_16;			\
+		u8 _dmsize = _is_slave ? _sconfig->dst_maxburst :	\
+			DW_DMA_MSIZE_16;			\
+								\
+		(DWC_CTLL_DST_MSIZE(_dmsize)			\
+		 | DWC_CTLL_SRC_MSIZE(_smsize)			\
+		 | DWC_CTLL_LLP_D_EN				\
+		 | DWC_CTLL_LLP_S_EN				\
+		 | DWC_CTLL_DMS(_dwc->dst_master)		\
+		 | DWC_CTLL_SMS(_dwc->src_master));		\
+	})
+
+/*
+ * Number of descriptors to allocate for each channel. This should be
+ * made configurable somehow; preferably, the clients (at least the
+ * ones using slave transfers) should be able to give us a hint.
+ */
+#define NR_DESCS_PER_CHANNEL	64
+
+/*----------------------------------------------------------------------*/
+
+static struct device *chan2dev(struct dma_chan *chan)
+{
+	return &chan->dev->device;
+}
+static struct device *chan2parent(struct dma_chan *chan)
+{
+	return chan->dev->device.parent;
+}
+
+static struct dw_desc *dwc_first_active(struct dw_dma_chan *dwc)
+{
+	return to_dw_desc(dwc->active_list.next);
+}
+
+static struct dw_desc *dwc_desc_get(struct dw_dma_chan *dwc)
+{
+	struct dw_desc *desc, *_desc;
+	struct dw_desc *ret = NULL;
+	unsigned int i = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	list_for_each_entry_safe(desc, _desc, &dwc->free_list, desc_node) {
+		i++;
+		if (async_tx_test_ack(&desc->txd)) {
+			list_del(&desc->desc_node);
+			ret = desc;
+			break;
+		}
+		dev_dbg(chan2dev(&dwc->chan), "desc %p not ACKed\n", desc);
+	}
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	dev_vdbg(chan2dev(&dwc->chan), "scanned %u descriptors on freelist\n", i);
+
+	return ret;
+}
+
+/*
+ * Move a descriptor, including any children, to the free list.
+ * `desc' must not be on any lists.
+ */
+static void dwc_desc_put(struct dw_dma_chan *dwc, struct dw_desc *desc)
+{
+	unsigned long flags;
+
+	if (desc) {
+		struct dw_desc *child;
+
+		spin_lock_irqsave(&dwc->lock, flags);
+		list_for_each_entry(child, &desc->tx_list, desc_node)
+			dev_vdbg(chan2dev(&dwc->chan),
+					"moving child desc %p to freelist\n",
+					child);
+		list_splice_init(&desc->tx_list, &dwc->free_list);
+		dev_vdbg(chan2dev(&dwc->chan), "moving desc %p to freelist\n", desc);
+		list_add(&desc->desc_node, &dwc->free_list);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+	}
+}
+
+static void dwc_initialize(struct dw_dma_chan *dwc)
+{
+	struct dw_dma *dw = to_dw_dma(dwc->chan.device);
+	struct dw_dma_slave *dws = dwc->chan.private;
+	u32 cfghi = DWC_CFGH_FIFO_MODE;
+	u32 cfglo = DWC_CFGL_CH_PRIOR(dwc->priority);
+
+	if (dwc->initialized == true)
+		return;
+
+	if (dws) {
+		/*
+		 * We need controller-specific data to set up slave
+		 * transfers.
+		 */
+		BUG_ON(!dws->dma_dev || dws->dma_dev != dw->dma.dev);
+
+		cfghi = dws->cfg_hi;
+		cfglo |= dws->cfg_lo & ~DWC_CFGL_CH_PRIOR_MASK;
+	} else {
+		if (dwc->direction == DMA_MEM_TO_DEV)
+			cfghi = DWC_CFGH_DST_PER(dwc->request_line);
+		else if (dwc->direction == DMA_DEV_TO_MEM)
+			cfghi = DWC_CFGH_SRC_PER(dwc->request_line);
+	}
+
+	channel_writel(dwc, CFG_LO, cfglo);
+	channel_writel(dwc, CFG_HI, cfghi);
+
+	/* Enable interrupts */
+	channel_set_bit(dw, MASK.XFER, dwc->mask);
+	channel_set_bit(dw, MASK.ERROR, dwc->mask);
+
+	dwc->initialized = true;
+}
+
+/*----------------------------------------------------------------------*/
+
+static inline unsigned int dwc_fast_fls(unsigned long long v)
+{
+	/*
+	 * We can be a lot more clever here, but this should take care
+	 * of the most common optimization.
+	 */
+	if (!(v & 7))
+		return 3;
+	else if (!(v & 3))
+		return 2;
+	else if (!(v & 1))
+		return 1;
+	return 0;
+}
+
+static inline void dwc_dump_chan_regs(struct dw_dma_chan *dwc)
+{
+	dev_err(chan2dev(&dwc->chan),
+		"  SAR: 0x%x DAR: 0x%x LLP: 0x%x CTL: 0x%x:%08x\n",
+		channel_readl(dwc, SAR),
+		channel_readl(dwc, DAR),
+		channel_readl(dwc, LLP),
+		channel_readl(dwc, CTL_HI),
+		channel_readl(dwc, CTL_LO));
+}
+
+static inline void dwc_chan_disable(struct dw_dma *dw, struct dw_dma_chan *dwc)
+{
+	channel_clear_bit(dw, CH_EN, dwc->mask);
+	while (dma_readl(dw, CH_EN) & dwc->mask)
+		cpu_relax();
+}
+
+/*----------------------------------------------------------------------*/
+
+/* Perform single block transfer */
+static inline void dwc_do_single_block(struct dw_dma_chan *dwc,
+				       struct dw_desc *desc)
+{
+	struct dw_dma	*dw = to_dw_dma(dwc->chan.device);
+	u32		ctllo;
+
+	/* Software emulation of LLP mode relies on interrupts to continue
+	 * multi block transfer. */
+	ctllo = desc->lli.ctllo | DWC_CTLL_INT_EN;
+
+	channel_writel(dwc, SAR, desc->lli.sar);
+	channel_writel(dwc, DAR, desc->lli.dar);
+	channel_writel(dwc, CTL_LO, ctllo);
+	channel_writel(dwc, CTL_HI, desc->lli.ctlhi);
+	channel_set_bit(dw, CH_EN, dwc->mask);
+
+	/* Move pointer to next descriptor */
+	dwc->tx_node_active = dwc->tx_node_active->next;
+}
+
+/* Called with dwc->lock held and bh disabled */
+static void dwc_dostart(struct dw_dma_chan *dwc, struct dw_desc *first)
+{
+	struct dw_dma	*dw = to_dw_dma(dwc->chan.device);
+	unsigned long	was_soft_llp;
+
+	/* ASSERT:  channel is idle */
+	if (dma_readl(dw, CH_EN) & dwc->mask) {
+		dev_err(chan2dev(&dwc->chan),
+			"BUG: Attempted to start non-idle channel\n");
+		dwc_dump_chan_regs(dwc);
+
+		/* The tasklet will hopefully advance the queue... */
+		return;
+	}
+
+	if (dwc->nollp) {
+		was_soft_llp = test_and_set_bit(DW_DMA_IS_SOFT_LLP,
+						&dwc->flags);
+		if (was_soft_llp) {
+			dev_err(chan2dev(&dwc->chan),
+				"BUG: Attempted to start new LLP transfer "
+				"inside ongoing one\n");
+			return;
+		}
+
+		dwc_initialize(dwc);
+
+		dwc->residue = first->total_len;
+		dwc->tx_node_active = &first->tx_list;
+
+		/* Submit first block */
+		dwc_do_single_block(dwc, first);
+
+		return;
+	}
+
+	dwc_initialize(dwc);
+
+	channel_writel(dwc, LLP, first->txd.phys);
+	channel_writel(dwc, CTL_LO,
+			DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
+	channel_writel(dwc, CTL_HI, 0);
+	channel_set_bit(dw, CH_EN, dwc->mask);
+}
+
+/*----------------------------------------------------------------------*/
+
+static void
+dwc_descriptor_complete(struct dw_dma_chan *dwc, struct dw_desc *desc,
+		bool callback_required)
+{
+	dma_async_tx_callback		callback = NULL;
+	void				*param = NULL;
+	struct dma_async_tx_descriptor	*txd = &desc->txd;
+	struct dw_desc			*child;
+	unsigned long			flags;
+
+	dev_vdbg(chan2dev(&dwc->chan), "descriptor %u complete\n", txd->cookie);
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	dma_cookie_complete(txd);
+	if (callback_required) {
+		callback = txd->callback;
+		param = txd->callback_param;
+	}
+
+	/* async_tx_ack */
+	list_for_each_entry(child, &desc->tx_list, desc_node)
+		async_tx_ack(&child->txd);
+	async_tx_ack(&desc->txd);
+
+	list_splice_init(&desc->tx_list, &dwc->free_list);
+	list_move(&desc->desc_node, &dwc->free_list);
+
+	if (!is_slave_direction(dwc->direction)) {
+		struct device *parent = chan2parent(&dwc->chan);
+		if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP)) {
+			if (txd->flags & DMA_COMPL_DEST_UNMAP_SINGLE)
+				dma_unmap_single(parent, desc->lli.dar,
+					desc->total_len, DMA_FROM_DEVICE);
+			else
+				dma_unmap_page(parent, desc->lli.dar,
+					desc->total_len, DMA_FROM_DEVICE);
+		}
+		if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP)) {
+			if (txd->flags & DMA_COMPL_SRC_UNMAP_SINGLE)
+				dma_unmap_single(parent, desc->lli.sar,
+					desc->total_len, DMA_TO_DEVICE);
+			else
+				dma_unmap_page(parent, desc->lli.sar,
+					desc->total_len, DMA_TO_DEVICE);
+		}
+	}
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	if (callback)
+		callback(param);
+}
+
+static void dwc_complete_all(struct dw_dma *dw, struct dw_dma_chan *dwc)
+{
+	struct dw_desc *desc, *_desc;
+	LIST_HEAD(list);
+	unsigned long flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	if (dma_readl(dw, CH_EN) & dwc->mask) {
+		dev_err(chan2dev(&dwc->chan),
+			"BUG: XFER bit set, but channel not idle!\n");
+
+		/* Try to continue after resetting the channel... */
+		dwc_chan_disable(dw, dwc);
+	}
+
+	/*
+	 * Submit queued descriptors ASAP, i.e. before we go through
+	 * the completed ones.
+	 */
+	list_splice_init(&dwc->active_list, &list);
+	if (!list_empty(&dwc->queue)) {
+		list_move(dwc->queue.next, &dwc->active_list);
+		dwc_dostart(dwc, dwc_first_active(dwc));
+	}
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	list_for_each_entry_safe(desc, _desc, &list, desc_node)
+		dwc_descriptor_complete(dwc, desc, true);
+}
+
+/* Returns how many bytes were already received from source */
+static inline u32 dwc_get_sent(struct dw_dma_chan *dwc)
+{
+	u32 ctlhi = channel_readl(dwc, CTL_HI);
+	u32 ctllo = channel_readl(dwc, CTL_LO);
+
+	return (ctlhi & DWC_CTLH_BLOCK_TS_MASK) * (1 << (ctllo >> 4 & 7));
+}
+
+static void dwc_scan_descriptors(struct dw_dma *dw, struct dw_dma_chan *dwc)
+{
+	dma_addr_t llp;
+	struct dw_desc *desc, *_desc;
+	struct dw_desc *child;
+	u32 status_xfer;
+	unsigned long flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	llp = channel_readl(dwc, LLP);
+	status_xfer = dma_readl(dw, RAW.XFER);
+
+	if (status_xfer & dwc->mask) {
+		/* Everything we've submitted is done */
+		dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+		if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags)) {
+			struct list_head *head, *active = dwc->tx_node_active;
+
+			/*
+			 * We are inside first active descriptor.
+			 * Otherwise something is really wrong.
+			 */
+			desc = dwc_first_active(dwc);
+
+			head = &desc->tx_list;
+			if (active != head) {
+				/* Update desc to reflect last sent one */
+				if (active != head->next)
+					desc = to_dw_desc(active->prev);
+
+				dwc->residue -= desc->len;
+
+				child = to_dw_desc(active);
+
+				/* Submit next block */
+				dwc_do_single_block(dwc, child);
+
+				spin_unlock_irqrestore(&dwc->lock, flags);
+				return;
+			}
+
+			/* We are done here */
+			clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
+		}
+
+		dwc->residue = 0;
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		dwc_complete_all(dw, dwc);
+		return;
+	}
+
+	if (list_empty(&dwc->active_list)) {
+		dwc->residue = 0;
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		return;
+	}
+
+	if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags)) {
+		dev_vdbg(chan2dev(&dwc->chan), "%s: soft LLP mode\n", __func__);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		return;
+	}
+
+	dev_vdbg(chan2dev(&dwc->chan), "%s: llp=0x%llx\n", __func__,
+			(unsigned long long)llp);
+
+	list_for_each_entry_safe(desc, _desc, &dwc->active_list, desc_node) {
+		/* Initial residue value */
+		dwc->residue = desc->total_len;
+
+		/* Check first descriptors addr */
+		if (desc->txd.phys == llp) {
+			spin_unlock_irqrestore(&dwc->lock, flags);
+			return;
+		}
+
+		/* Check first descriptors llp */
+		if (desc->lli.llp == llp) {
+			/* This one is currently in progress */
+			dwc->residue -= dwc_get_sent(dwc);
+			spin_unlock_irqrestore(&dwc->lock, flags);
+			return;
+		}
+
+		dwc->residue -= desc->len;
+		list_for_each_entry(child, &desc->tx_list, desc_node) {
+			if (child->lli.llp == llp) {
+				/* Currently in progress */
+				dwc->residue -= dwc_get_sent(dwc);
+				spin_unlock_irqrestore(&dwc->lock, flags);
+				return;
+			}
+			dwc->residue -= child->len;
+		}
+
+		/*
+		 * No descriptors so far seem to be in progress, i.e.
+		 * this one must be done.
+		 */
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		dwc_descriptor_complete(dwc, desc, true);
+		spin_lock_irqsave(&dwc->lock, flags);
+	}
+
+	dev_err(chan2dev(&dwc->chan),
+		"BUG: All descriptors done, but channel not idle!\n");
+
+	/* Try to continue after resetting the channel... */
+	dwc_chan_disable(dw, dwc);
+
+	if (!list_empty(&dwc->queue)) {
+		list_move(dwc->queue.next, &dwc->active_list);
+		dwc_dostart(dwc, dwc_first_active(dwc));
+	}
+	spin_unlock_irqrestore(&dwc->lock, flags);
+}
+
+static inline void dwc_dump_lli(struct dw_dma_chan *dwc, struct dw_lli *lli)
+{
+	dev_crit(chan2dev(&dwc->chan), "  desc: s0x%x d0x%x l0x%x c0x%x:%x\n",
+		 lli->sar, lli->dar, lli->llp, lli->ctlhi, lli->ctllo);
+}
+
+static void dwc_handle_error(struct dw_dma *dw, struct dw_dma_chan *dwc)
+{
+	struct dw_desc *bad_desc;
+	struct dw_desc *child;
+	unsigned long flags;
+
+	dwc_scan_descriptors(dw, dwc);
+
+	spin_lock_irqsave(&dwc->lock, flags);
+
+	/*
+	 * The descriptor currently at the head of the active list is
+	 * borked. Since we don't have any way to report errors, we'll
+	 * just have to scream loudly and try to carry on.
+	 */
+	bad_desc = dwc_first_active(dwc);
+	list_del_init(&bad_desc->desc_node);
+	list_move(dwc->queue.next, dwc->active_list.prev);
+
+	/* Clear the error flag and try to restart the controller */
+	dma_writel(dw, CLEAR.ERROR, dwc->mask);
+	if (!list_empty(&dwc->active_list))
+		dwc_dostart(dwc, dwc_first_active(dwc));
+
+	/*
+	 * WARN may seem harsh, but since this only happens
+	 * when someone submits a bad physical address in a
+	 * descriptor, we should consider ourselves lucky that the
+	 * controller flagged an error instead of scribbling over
+	 * random memory locations.
+	 */
+	dev_WARN(chan2dev(&dwc->chan), "Bad descriptor submitted for DMA!\n"
+				       "  cookie: %d\n", bad_desc->txd.cookie);
+	dwc_dump_lli(dwc, &bad_desc->lli);
+	list_for_each_entry(child, &bad_desc->tx_list, desc_node)
+		dwc_dump_lli(dwc, &child->lli);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	/* Pretend the descriptor completed successfully */
+	dwc_descriptor_complete(dwc, bad_desc, true);
+}
+
+/* --------------------- Cyclic DMA API extensions -------------------- */
+
+dma_addr_t dw_dma_get_src_addr(struct dma_chan *chan)
+{
+	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+	return channel_readl(dwc, SAR);
+}
+EXPORT_SYMBOL(dw_dma_get_src_addr);
+
+dma_addr_t dw_dma_get_dst_addr(struct dma_chan *chan)
+{
+	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+	return channel_readl(dwc, DAR);
+}
+EXPORT_SYMBOL(dw_dma_get_dst_addr);
+
+/* Called with dwc->lock held and all DMAC interrupts disabled */
+static void dwc_handle_cyclic(struct dw_dma *dw, struct dw_dma_chan *dwc,
+		u32 status_err, u32 status_xfer)
+{
+	unsigned long flags;
+
+	if (dwc->mask) {
+		void (*callback)(void *param);
+		void *callback_param;
+
+		dev_vdbg(chan2dev(&dwc->chan), "new cyclic period llp 0x%08x\n",
+				channel_readl(dwc, LLP));
+
+		callback = dwc->cdesc->period_callback;
+		callback_param = dwc->cdesc->period_callback_param;
+
+		if (callback)
+			callback(callback_param);
+	}
+
+	/*
+	 * Error and transfer complete are highly unlikely, and will most
+	 * likely be due to a configuration error by the user.
+	 */
+	if (unlikely(status_err & dwc->mask) ||
+			unlikely(status_xfer & dwc->mask)) {
+		int i;
+
+		dev_err(chan2dev(&dwc->chan), "cyclic DMA unexpected %s "
+				"interrupt, stopping DMA transfer\n",
+				status_xfer ? "xfer" : "error");
+
+		spin_lock_irqsave(&dwc->lock, flags);
+
+		dwc_dump_chan_regs(dwc);
+
+		dwc_chan_disable(dw, dwc);
+
+		/* Make sure DMA does not restart by loading a new list */
+		channel_writel(dwc, LLP, 0);
+		channel_writel(dwc, CTL_LO, 0);
+		channel_writel(dwc, CTL_HI, 0);
+
+		dma_writel(dw, CLEAR.ERROR, dwc->mask);
+		dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+		for (i = 0; i < dwc->cdesc->periods; i++)
+			dwc_dump_lli(dwc, &dwc->cdesc->desc[i]->lli);
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+	}
+}
+
+/* ------------------------------------------------------------------------- */
+
+static void dw_dma_tasklet(unsigned long data)
+{
+	struct dw_dma *dw = (struct dw_dma *)data;
+	struct dw_dma_chan *dwc;
+	u32 status_xfer;
+	u32 status_err;
+	int i;
+
+	status_xfer = dma_readl(dw, RAW.XFER);
+	status_err = dma_readl(dw, RAW.ERROR);
+
+	dev_vdbg(dw->dma.dev, "%s: status_err=%x\n", __func__, status_err);
+
+	for (i = 0; i < dw->dma.chancnt; i++) {
+		dwc = &dw->chan[i];
+		if (test_bit(DW_DMA_IS_CYCLIC, &dwc->flags))
+			dwc_handle_cyclic(dw, dwc, status_err, status_xfer);
+		else if (status_err & (1 << i))
+			dwc_handle_error(dw, dwc);
+		else if (status_xfer & (1 << i))
+			dwc_scan_descriptors(dw, dwc);
+	}
+
+	/*
+	 * Re-enable interrupts.
+	 */
+	channel_set_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_set_bit(dw, MASK.ERROR, dw->all_chan_mask);
+}
+
+static irqreturn_t dw_dma_interrupt(int irq, void *dev_id)
+{
+	struct dw_dma *dw = dev_id;
+	u32 status;
+
+	dev_vdbg(dw->dma.dev, "%s: status=0x%x\n", __func__,
+			dma_readl(dw, STATUS_INT));
+
+	/*
+	 * Just disable the interrupts. We'll turn them back on in the
+	 * softirq handler.
+	 */
+	channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
+
+	status = dma_readl(dw, STATUS_INT);
+	if (status) {
+		dev_err(dw->dma.dev,
+			"BUG: Unexpected interrupts pending: 0x%x\n",
+			status);
+
+		/* Try to recover */
+		channel_clear_bit(dw, MASK.XFER, (1 << 8) - 1);
+		channel_clear_bit(dw, MASK.SRC_TRAN, (1 << 8) - 1);
+		channel_clear_bit(dw, MASK.DST_TRAN, (1 << 8) - 1);
+		channel_clear_bit(dw, MASK.ERROR, (1 << 8) - 1);
+	}
+
+	tasklet_schedule(&dw->tasklet);
+
+	return IRQ_HANDLED;
+}
+
+/*----------------------------------------------------------------------*/
+
+static dma_cookie_t dwc_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct dw_desc		*desc = txd_to_dw_desc(tx);
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(tx->chan);
+	dma_cookie_t		cookie;
+	unsigned long		flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	cookie = dma_cookie_assign(tx);
+
+	/*
+	 * REVISIT: We should attempt to chain as many descriptors as
+	 * possible, perhaps even appending to those already submitted
+	 * for DMA. But this is hard to do in a race-free manner.
+	 */
+	if (list_empty(&dwc->active_list)) {
+		dev_vdbg(chan2dev(tx->chan), "%s: started %u\n", __func__,
+				desc->txd.cookie);
+		list_add_tail(&desc->desc_node, &dwc->active_list);
+		dwc_dostart(dwc, dwc_first_active(dwc));
+	} else {
+		dev_vdbg(chan2dev(tx->chan), "%s: queued %u\n", __func__,
+				desc->txd.cookie);
+
+		list_add_tail(&desc->desc_node, &dwc->queue);
+	}
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return cookie;
+}
+
+static struct dma_async_tx_descriptor *
+dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_desc		*desc;
+	struct dw_desc		*first;
+	struct dw_desc		*prev;
+	size_t			xfer_count;
+	size_t			offset;
+	unsigned int		src_width;
+	unsigned int		dst_width;
+	unsigned int		data_width;
+	u32			ctllo;
+
+	dev_vdbg(chan2dev(chan),
+			"%s: d0x%llx s0x%llx l0x%zx f0x%lx\n", __func__,
+			(unsigned long long)dest, (unsigned long long)src,
+			len, flags);
+
+	if (unlikely(!len)) {
+		dev_dbg(chan2dev(chan), "%s: length is zero!\n", __func__);
+		return NULL;
+	}
+
+	dwc->direction = DMA_MEM_TO_MEM;
+
+	data_width = min_t(unsigned int, dw->data_width[dwc->src_master],
+			   dw->data_width[dwc->dst_master]);
+
+	src_width = dst_width = min_t(unsigned int, data_width,
+				      dwc_fast_fls(src | dest | len));
+
+	ctllo = DWC_DEFAULT_CTLLO(chan)
+			| DWC_CTLL_DST_WIDTH(dst_width)
+			| DWC_CTLL_SRC_WIDTH(src_width)
+			| DWC_CTLL_DST_INC
+			| DWC_CTLL_SRC_INC
+			| DWC_CTLL_FC_M2M;
+	prev = first = NULL;
+
+	for (offset = 0; offset < len; offset += xfer_count << src_width) {
+		xfer_count = min_t(size_t, (len - offset) >> src_width,
+					   dwc->block_size);
+
+		desc = dwc_desc_get(dwc);
+		if (!desc)
+			goto err_desc_get;
+
+		desc->lli.sar = src + offset;
+		desc->lli.dar = dest + offset;
+		desc->lli.ctllo = ctllo;
+		desc->lli.ctlhi = xfer_count;
+		desc->len = xfer_count << src_width;
+
+		if (!first) {
+			first = desc;
+		} else {
+			prev->lli.llp = desc->txd.phys;
+			list_add_tail(&desc->desc_node,
+					&first->tx_list);
+		}
+		prev = desc;
+	}
+
+	if (flags & DMA_PREP_INTERRUPT)
+		/* Trigger interrupt after last block */
+		prev->lli.ctllo |= DWC_CTLL_INT_EN;
+
+	prev->lli.llp = 0;
+	first->txd.flags = flags;
+	first->total_len = len;
+
+	return &first->txd;
+
+err_desc_get:
+	dwc_desc_put(dwc, first);
+	return NULL;
+}
+
+static struct dma_async_tx_descriptor *
+dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_transfer_direction direction,
+		unsigned long flags, void *context)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dma_slave_config	*sconfig = &dwc->dma_sconfig;
+	struct dw_desc		*prev;
+	struct dw_desc		*first;
+	u32			ctllo;
+	dma_addr_t		reg;
+	unsigned int		reg_width;
+	unsigned int		mem_width;
+	unsigned int		data_width;
+	unsigned int		i;
+	struct scatterlist	*sg;
+	size_t			total_len = 0;
+
+	dev_vdbg(chan2dev(chan), "%s\n", __func__);
+
+	if (unlikely(!is_slave_direction(direction) || !sg_len))
+		return NULL;
+
+	dwc->direction = direction;
+
+	prev = first = NULL;
+
+	switch (direction) {
+	case DMA_MEM_TO_DEV:
+		reg_width = __fls(sconfig->dst_addr_width);
+		reg = sconfig->dst_addr;
+		ctllo = (DWC_DEFAULT_CTLLO(chan)
+				| DWC_CTLL_DST_WIDTH(reg_width)
+				| DWC_CTLL_DST_FIX
+				| DWC_CTLL_SRC_INC);
+
+		ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
+			DWC_CTLL_FC(DW_DMA_FC_D_M2P);
+
+		data_width = dw->data_width[dwc->src_master];
+
+		for_each_sg(sgl, sg, sg_len, i) {
+			struct dw_desc	*desc;
+			u32		len, dlen, mem;
+
+			mem = sg_dma_address(sg);
+			len = sg_dma_len(sg);
+
+			mem_width = min_t(unsigned int,
+					  data_width, dwc_fast_fls(mem | len));
+
+slave_sg_todev_fill_desc:
+			desc = dwc_desc_get(dwc);
+			if (!desc) {
+				dev_err(chan2dev(chan),
+					"not enough descriptors available\n");
+				goto err_desc_get;
+			}
+
+			desc->lli.sar = mem;
+			desc->lli.dar = reg;
+			desc->lli.ctllo = ctllo | DWC_CTLL_SRC_WIDTH(mem_width);
+			if ((len >> mem_width) > dwc->block_size) {
+				dlen = dwc->block_size << mem_width;
+				mem += dlen;
+				len -= dlen;
+			} else {
+				dlen = len;
+				len = 0;
+			}
+
+			desc->lli.ctlhi = dlen >> mem_width;
+			desc->len = dlen;
+
+			if (!first) {
+				first = desc;
+			} else {
+				prev->lli.llp = desc->txd.phys;
+				list_add_tail(&desc->desc_node,
+						&first->tx_list);
+			}
+			prev = desc;
+			total_len += dlen;
+
+			if (len)
+				goto slave_sg_todev_fill_desc;
+		}
+		break;
+	case DMA_DEV_TO_MEM:
+		reg_width = __fls(sconfig->src_addr_width);
+		reg = sconfig->src_addr;
+		ctllo = (DWC_DEFAULT_CTLLO(chan)
+				| DWC_CTLL_SRC_WIDTH(reg_width)
+				| DWC_CTLL_DST_INC
+				| DWC_CTLL_SRC_FIX);
+
+		ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
+			DWC_CTLL_FC(DW_DMA_FC_D_P2M);
+
+		data_width = dw->data_width[dwc->dst_master];
+
+		for_each_sg(sgl, sg, sg_len, i) {
+			struct dw_desc	*desc;
+			u32		len, dlen, mem;
+
+			mem = sg_dma_address(sg);
+			len = sg_dma_len(sg);
+
+			mem_width = min_t(unsigned int,
+					  data_width, dwc_fast_fls(mem | len));
+
+slave_sg_fromdev_fill_desc:
+			desc = dwc_desc_get(dwc);
+			if (!desc) {
+				dev_err(chan2dev(chan),
+						"not enough descriptors available\n");
+				goto err_desc_get;
+			}
+
+			desc->lli.sar = reg;
+			desc->lli.dar = mem;
+			desc->lli.ctllo = ctllo | DWC_CTLL_DST_WIDTH(mem_width);
+			if ((len >> reg_width) > dwc->block_size) {
+				dlen = dwc->block_size << reg_width;
+				mem += dlen;
+				len -= dlen;
+			} else {
+				dlen = len;
+				len = 0;
+			}
+			desc->lli.ctlhi = dlen >> reg_width;
+			desc->len = dlen;
+
+			if (!first) {
+				first = desc;
+			} else {
+				prev->lli.llp = desc->txd.phys;
+				list_add_tail(&desc->desc_node,
+						&first->tx_list);
+			}
+			prev = desc;
+			total_len += dlen;
+
+			if (len)
+				goto slave_sg_fromdev_fill_desc;
+		}
+		break;
+	default:
+		return NULL;
+	}
+
+	if (flags & DMA_PREP_INTERRUPT)
+		/* Trigger interrupt after last block */
+		prev->lli.ctllo |= DWC_CTLL_INT_EN;
+
+	prev->lli.llp = 0;
+	first->total_len = total_len;
+
+	return &first->txd;
+
+err_desc_get:
+	dwc_desc_put(dwc, first);
+	return NULL;
+}
+
+/*
+ * Fix sconfig's burst size according to dw_dmac. We need to convert them as:
+ * 1 -> 0, 4 -> 1, 8 -> 2, 16 -> 3.
+ *
+ * NOTE: burst size 2 is not supported by controller.
+ *
+ * This can be done by finding least significant bit set: n & (n - 1)
+ */
+static inline void convert_burst(u32 *maxburst)
+{
+	if (*maxburst > 1)
+		*maxburst = fls(*maxburst) - 2;
+	else
+		*maxburst = 0;
+}
+
+static int
+set_runtime_config(struct dma_chan *chan, struct dma_slave_config *sconfig)
+{
+	struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
+
+	/* Check if chan will be configured for slave transfers */
+	if (!is_slave_direction(sconfig->direction))
+		return -EINVAL;
+
+	memcpy(&dwc->dma_sconfig, sconfig, sizeof(*sconfig));
+	dwc->direction = sconfig->direction;
+
+	/* Take the request line from slave_id member */
+	if (dwc->request_line == ~0)
+		dwc->request_line = sconfig->slave_id;
+
+	convert_burst(&dwc->dma_sconfig.src_maxburst);
+	convert_burst(&dwc->dma_sconfig.dst_maxburst);
+
+	return 0;
+}
+
+static inline void dwc_chan_pause(struct dw_dma_chan *dwc)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+	unsigned int count = 20;	/* timeout iterations */
+
+	channel_writel(dwc, CFG_LO, cfglo | DWC_CFGL_CH_SUSP);
+	while (!(channel_readl(dwc, CFG_LO) & DWC_CFGL_FIFO_EMPTY) && count--)
+		udelay(2);
+
+	dwc->paused = true;
+}
+
+static inline void dwc_chan_resume(struct dw_dma_chan *dwc)
+{
+	u32 cfglo = channel_readl(dwc, CFG_LO);
+
+	channel_writel(dwc, CFG_LO, cfglo & ~DWC_CFGL_CH_SUSP);
+
+	dwc->paused = false;
+}
+
+static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+		       unsigned long arg)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_desc		*desc, *_desc;
+	unsigned long		flags;
+	LIST_HEAD(list);
+
+	if (cmd == DMA_PAUSE) {
+		spin_lock_irqsave(&dwc->lock, flags);
+
+		dwc_chan_pause(dwc);
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+	} else if (cmd == DMA_RESUME) {
+		if (!dwc->paused)
+			return 0;
+
+		spin_lock_irqsave(&dwc->lock, flags);
+
+		dwc_chan_resume(dwc);
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+	} else if (cmd == DMA_TERMINATE_ALL) {
+		spin_lock_irqsave(&dwc->lock, flags);
+
+		clear_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags);
+
+		dwc_chan_disable(dw, dwc);
+
+		dwc_chan_resume(dwc);
+
+		/* active_list entries will end up before queued entries */
+		list_splice_init(&dwc->queue, &list);
+		list_splice_init(&dwc->active_list, &list);
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		/* Flush all pending and queued descriptors */
+		list_for_each_entry_safe(desc, _desc, &list, desc_node)
+			dwc_descriptor_complete(dwc, desc, false);
+	} else if (cmd == DMA_SLAVE_CONFIG) {
+		return set_runtime_config(chan, (struct dma_slave_config *)arg);
+	} else {
+		return -ENXIO;
+	}
+
+	return 0;
+}
+
+static inline u32 dwc_get_residue(struct dw_dma_chan *dwc)
+{
+	unsigned long flags;
+	u32 residue;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+
+	residue = dwc->residue;
+	if (test_bit(DW_DMA_IS_SOFT_LLP, &dwc->flags) && residue)
+		residue -= dwc_get_sent(dwc);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+	return residue;
+}
+
+static enum dma_status
+dwc_tx_status(struct dma_chan *chan,
+	      dma_cookie_t cookie,
+	      struct dma_tx_state *txstate)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	enum dma_status		ret;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret != DMA_SUCCESS) {
+		dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
+
+		ret = dma_cookie_status(chan, cookie, txstate);
+	}
+
+	if (ret != DMA_SUCCESS)
+		dma_set_residue(txstate, dwc_get_residue(dwc));
+
+	if (dwc->paused)
+		return DMA_PAUSED;
+
+	return ret;
+}
+
+static void dwc_issue_pending(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+
+	if (!list_empty(&dwc->queue))
+		dwc_scan_descriptors(to_dw_dma(chan->device), dwc);
+}
+
+static int dwc_alloc_chan_resources(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_desc		*desc;
+	int			i;
+	unsigned long		flags;
+
+	dev_vdbg(chan2dev(chan), "%s\n", __func__);
+
+	/* ASSERT:  channel is idle */
+	if (dma_readl(dw, CH_EN) & dwc->mask) {
+		dev_dbg(chan2dev(chan), "DMA channel not idle?\n");
+		return -EIO;
+	}
+
+	dma_cookie_init(chan);
+
+	/*
+	 * NOTE: some controllers may have additional features that we
+	 * need to initialize here, like "scatter-gather" (which
+	 * doesn't mean what you think it means), and status writeback.
+	 */
+
+	dwc_set_masters(dwc);
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	i = dwc->descs_allocated;
+	while (dwc->descs_allocated < NR_DESCS_PER_CHANNEL) {
+		dma_addr_t phys;
+
+		spin_unlock_irqrestore(&dwc->lock, flags);
+
+		desc = dma_pool_alloc(dw->desc_pool, GFP_ATOMIC, &phys);
+		if (!desc)
+			goto err_desc_alloc;
+
+		memset(desc, 0, sizeof(struct dw_desc));
+
+		INIT_LIST_HEAD(&desc->tx_list);
+		dma_async_tx_descriptor_init(&desc->txd, chan);
+		desc->txd.tx_submit = dwc_tx_submit;
+		desc->txd.flags = DMA_CTRL_ACK;
+		desc->txd.phys = phys;
+
+		dwc_desc_put(dwc, desc);
+
+		spin_lock_irqsave(&dwc->lock, flags);
+		i = ++dwc->descs_allocated;
+	}
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	dev_dbg(chan2dev(chan), "%s: allocated %d descriptors\n", __func__, i);
+
+	return i;
+
+err_desc_alloc:
+	dev_info(chan2dev(chan), "only allocated %d descriptors\n", i);
+
+	return i;
+}
+
+static void dwc_free_chan_resources(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(chan->device);
+	struct dw_desc		*desc, *_desc;
+	unsigned long		flags;
+	LIST_HEAD(list);
+
+	dev_dbg(chan2dev(chan), "%s: descs allocated=%u\n", __func__,
+			dwc->descs_allocated);
+
+	/* ASSERT:  channel is idle */
+	BUG_ON(!list_empty(&dwc->active_list));
+	BUG_ON(!list_empty(&dwc->queue));
+	BUG_ON(dma_readl(to_dw_dma(chan->device), CH_EN) & dwc->mask);
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	list_splice_init(&dwc->free_list, &list);
+	dwc->descs_allocated = 0;
+	dwc->initialized = false;
+	dwc->request_line = ~0;
+
+	/* Disable interrupts */
+	channel_clear_bit(dw, MASK.XFER, dwc->mask);
+	channel_clear_bit(dw, MASK.ERROR, dwc->mask);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	list_for_each_entry_safe(desc, _desc, &list, desc_node) {
+		dev_vdbg(chan2dev(chan), "  freeing descriptor %p\n", desc);
+		dma_pool_free(dw->desc_pool, desc, desc->txd.phys);
+	}
+
+	dev_vdbg(chan2dev(chan), "%s: done\n", __func__);
+}
+
+/* --------------------- Cyclic DMA API extensions -------------------- */
+
+/**
+ * dw_dma_cyclic_start - start the cyclic DMA transfer
+ * @chan: the DMA channel to start
+ *
+ * Must be called with soft interrupts disabled. Returns zero on success or
+ * -errno on failure.
+ */
+int dw_dma_cyclic_start(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(dwc->chan.device);
+	unsigned long		flags;
+
+	if (!test_bit(DW_DMA_IS_CYCLIC, &dwc->flags)) {
+		dev_err(chan2dev(&dwc->chan), "missing prep for cyclic DMA\n");
+		return -ENODEV;
+	}
+
+	spin_lock_irqsave(&dwc->lock, flags);
+
+	/* Assert channel is idle */
+	if (dma_readl(dw, CH_EN) & dwc->mask) {
+		dev_err(chan2dev(&dwc->chan),
+			"BUG: Attempted to start non-idle channel\n");
+		dwc_dump_chan_regs(dwc);
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		return -EBUSY;
+	}
+
+	dma_writel(dw, CLEAR.ERROR, dwc->mask);
+	dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+	/* Setup DMAC channel registers */
+	channel_writel(dwc, LLP, dwc->cdesc->desc[0]->txd.phys);
+	channel_writel(dwc, CTL_LO, DWC_CTLL_LLP_D_EN | DWC_CTLL_LLP_S_EN);
+	channel_writel(dwc, CTL_HI, 0);
+
+	channel_set_bit(dw, CH_EN, dwc->mask);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(dw_dma_cyclic_start);
+
+/**
+ * dw_dma_cyclic_stop - stop the cyclic DMA transfer
+ * @chan: the DMA channel to stop
+ *
+ * Must be called with soft interrupts disabled.
+ */
+void dw_dma_cyclic_stop(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(dwc->chan.device);
+	unsigned long		flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+
+	dwc_chan_disable(dw, dwc);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+}
+EXPORT_SYMBOL(dw_dma_cyclic_stop);
+
+/**
+ * dw_dma_cyclic_prep - prepare the cyclic DMA transfer
+ * @chan: the DMA channel to prepare
+ * @buf_addr: physical DMA address where the buffer starts
+ * @buf_len: total number of bytes for the entire buffer
+ * @period_len: number of bytes for each period
+ * @direction: transfer direction, to or from device
+ *
+ * Must be called before trying to start the transfer. Returns a valid struct
+ * dw_cyclic_desc if successful or an ERR_PTR(-errno) if not successful.
+ */
+struct dw_cyclic_desc *dw_dma_cyclic_prep(struct dma_chan *chan,
+		dma_addr_t buf_addr, size_t buf_len, size_t period_len,
+		enum dma_transfer_direction direction)
+{
+	struct dw_dma_chan		*dwc = to_dw_dma_chan(chan);
+	struct dma_slave_config		*sconfig = &dwc->dma_sconfig;
+	struct dw_cyclic_desc		*cdesc;
+	struct dw_cyclic_desc		*retval = NULL;
+	struct dw_desc			*desc;
+	struct dw_desc			*last = NULL;
+	unsigned long			was_cyclic;
+	unsigned int			reg_width;
+	unsigned int			periods;
+	unsigned int			i;
+	unsigned long			flags;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	if (dwc->nollp) {
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		dev_dbg(chan2dev(&dwc->chan),
+				"channel doesn't support LLP transfers\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!list_empty(&dwc->queue) || !list_empty(&dwc->active_list)) {
+		spin_unlock_irqrestore(&dwc->lock, flags);
+		dev_dbg(chan2dev(&dwc->chan),
+				"queue and/or active list are not empty\n");
+		return ERR_PTR(-EBUSY);
+	}
+
+	was_cyclic = test_and_set_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+	spin_unlock_irqrestore(&dwc->lock, flags);
+	if (was_cyclic) {
+		dev_dbg(chan2dev(&dwc->chan),
+				"channel already prepared for cyclic DMA\n");
+		return ERR_PTR(-EBUSY);
+	}
+
+	retval = ERR_PTR(-EINVAL);
+
+	if (unlikely(!is_slave_direction(direction)))
+		goto out_err;
+
+	dwc->direction = direction;
+
+	if (direction == DMA_MEM_TO_DEV)
+		reg_width = __ffs(sconfig->dst_addr_width);
+	else
+		reg_width = __ffs(sconfig->src_addr_width);
+
+	periods = buf_len / period_len;
+
+	/* Check for too big/unaligned periods and unaligned DMA buffer. */
+	if (period_len > (dwc->block_size << reg_width))
+		goto out_err;
+	if (unlikely(period_len & ((1 << reg_width) - 1)))
+		goto out_err;
+	if (unlikely(buf_addr & ((1 << reg_width) - 1)))
+		goto out_err;
+
+	retval = ERR_PTR(-ENOMEM);
+
+	if (periods > NR_DESCS_PER_CHANNEL)
+		goto out_err;
+
+	cdesc = kzalloc(sizeof(struct dw_cyclic_desc), GFP_KERNEL);
+	if (!cdesc)
+		goto out_err;
+
+	cdesc->desc = kzalloc(sizeof(struct dw_desc *) * periods, GFP_KERNEL);
+	if (!cdesc->desc)
+		goto out_err_alloc;
+
+	for (i = 0; i < periods; i++) {
+		desc = dwc_desc_get(dwc);
+		if (!desc)
+			goto out_err_desc_get;
+
+		switch (direction) {
+		case DMA_MEM_TO_DEV:
+			desc->lli.dar = sconfig->dst_addr;
+			desc->lli.sar = buf_addr + (period_len * i);
+			desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan)
+					| DWC_CTLL_DST_WIDTH(reg_width)
+					| DWC_CTLL_SRC_WIDTH(reg_width)
+					| DWC_CTLL_DST_FIX
+					| DWC_CTLL_SRC_INC
+					| DWC_CTLL_INT_EN);
+
+			desc->lli.ctllo |= sconfig->device_fc ?
+				DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
+				DWC_CTLL_FC(DW_DMA_FC_D_M2P);
+
+			break;
+		case DMA_DEV_TO_MEM:
+			desc->lli.dar = buf_addr + (period_len * i);
+			desc->lli.sar = sconfig->src_addr;
+			desc->lli.ctllo = (DWC_DEFAULT_CTLLO(chan)
+					| DWC_CTLL_SRC_WIDTH(reg_width)
+					| DWC_CTLL_DST_WIDTH(reg_width)
+					| DWC_CTLL_DST_INC
+					| DWC_CTLL_SRC_FIX
+					| DWC_CTLL_INT_EN);
+
+			desc->lli.ctllo |= sconfig->device_fc ?
+				DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
+				DWC_CTLL_FC(DW_DMA_FC_D_P2M);
+
+			break;
+		default:
+			break;
+		}
+
+		desc->lli.ctlhi = (period_len >> reg_width);
+		cdesc->desc[i] = desc;
+
+		if (last)
+			last->lli.llp = desc->txd.phys;
+
+		last = desc;
+	}
+
+	/* Let's make a cyclic list */
+	last->lli.llp = cdesc->desc[0]->txd.phys;
+
+	dev_dbg(chan2dev(&dwc->chan), "cyclic prepared buf 0x%llx len %zu "
+			"period %zu periods %d\n", (unsigned long long)buf_addr,
+			buf_len, period_len, periods);
+
+	cdesc->periods = periods;
+	dwc->cdesc = cdesc;
+
+	return cdesc;
+
+out_err_desc_get:
+	while (i--)
+		dwc_desc_put(dwc, cdesc->desc[i]);
+out_err_alloc:
+	kfree(cdesc);
+out_err:
+	clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+	return (struct dw_cyclic_desc *)retval;
+}
+EXPORT_SYMBOL(dw_dma_cyclic_prep);
+
+/**
+ * dw_dma_cyclic_free - free a prepared cyclic DMA transfer
+ * @chan: the DMA channel to free
+ */
+void dw_dma_cyclic_free(struct dma_chan *chan)
+{
+	struct dw_dma_chan	*dwc = to_dw_dma_chan(chan);
+	struct dw_dma		*dw = to_dw_dma(dwc->chan.device);
+	struct dw_cyclic_desc	*cdesc = dwc->cdesc;
+	int			i;
+	unsigned long		flags;
+
+	dev_dbg(chan2dev(&dwc->chan), "%s\n", __func__);
+
+	if (!cdesc)
+		return;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+
+	dwc_chan_disable(dw, dwc);
+
+	dma_writel(dw, CLEAR.ERROR, dwc->mask);
+	dma_writel(dw, CLEAR.XFER, dwc->mask);
+
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	for (i = 0; i < cdesc->periods; i++)
+		dwc_desc_put(dwc, cdesc->desc[i]);
+
+	kfree(cdesc->desc);
+	kfree(cdesc);
+
+	clear_bit(DW_DMA_IS_CYCLIC, &dwc->flags);
+}
+EXPORT_SYMBOL(dw_dma_cyclic_free);
+
+/*----------------------------------------------------------------------*/
+
+static void dw_dma_off(struct dw_dma *dw)
+{
+	int i;
+
+	dma_writel(dw, CFG, 0);
+
+	channel_clear_bit(dw, MASK.XFER, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.SRC_TRAN, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.DST_TRAN, dw->all_chan_mask);
+	channel_clear_bit(dw, MASK.ERROR, dw->all_chan_mask);
+
+	while (dma_readl(dw, CFG) & DW_CFG_DMA_EN)
+		cpu_relax();
+
+	for (i = 0; i < dw->dma.chancnt; i++)
+		dw->chan[i].initialized = false;
+}
+
+int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
+{
+	struct dw_dma		*dw;
+	size_t			size;
+	bool			autocfg;
+	unsigned int		dw_params;
+	unsigned int		nr_channels;
+	unsigned int		max_blk_size = 0;
+	int			err;
+	int			i;
+
+	dw_params = dma_read_byaddr(chip->regs, DW_PARAMS);
+	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
+
+	dev_dbg(chip->dev, "DW_PARAMS: 0x%08x\n", dw_params);
+
+	if (!pdata && autocfg) {
+		pdata = devm_kzalloc(chip->dev, sizeof(*pdata), GFP_KERNEL);
+		if (!pdata)
+			return -ENOMEM;
+
+		/* Fill platform data with the default values */
+		pdata->is_private = true;
+		pdata->chan_allocation_order = CHAN_ALLOCATION_ASCENDING;
+		pdata->chan_priority = CHAN_PRIORITY_ASCENDING;
+	} else if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
+		return -EINVAL;
+
+	if (autocfg)
+		nr_channels = (dw_params >> DW_PARAMS_NR_CHAN & 0x7) + 1;
+	else
+		nr_channels = pdata->nr_channels;
+
+	size = sizeof(struct dw_dma) + nr_channels * sizeof(struct dw_dma_chan);
+	dw = devm_kzalloc(chip->dev, size, GFP_KERNEL);
+	if (!dw)
+		return -ENOMEM;
+
+	dw->clk = devm_clk_get(chip->dev, "hclk");
+	if (IS_ERR(dw->clk))
+		return PTR_ERR(dw->clk);
+	clk_prepare_enable(dw->clk);
+
+	dw->regs = chip->regs;
+	chip->dw = dw;
+
+	/* Get hardware configuration parameters */
+	if (autocfg) {
+		max_blk_size = dma_readl(dw, MAX_BLK_SIZE);
+
+		dw->nr_masters = (dw_params >> DW_PARAMS_NR_MASTER & 3) + 1;
+		for (i = 0; i < dw->nr_masters; i++) {
+			dw->data_width[i] =
+				(dw_params >> DW_PARAMS_DATA_WIDTH(i) & 3) + 2;
+		}
+	} else {
+		dw->nr_masters = pdata->nr_masters;
+		memcpy(dw->data_width, pdata->data_width, 4);
+	}
+
+	/* Calculate all channel mask before DMA setup */
+	dw->all_chan_mask = (1 << nr_channels) - 1;
+
+	/* Force dma off, just in case */
+	dw_dma_off(dw);
+
+	/* Disable BLOCK interrupts as well */
+	channel_clear_bit(dw, MASK.BLOCK, dw->all_chan_mask);
+
+	err = devm_request_irq(chip->dev, chip->irq, dw_dma_interrupt, 0,
+			       "dw_dmac", dw);
+	if (err)
+		return err;
+
+	/* Create a pool of consistent memory blocks for hardware descriptors */
+	dw->desc_pool = dmam_pool_create("dw_dmac_desc_pool", chip->dev,
+					 sizeof(struct dw_desc), 4, 0);
+	if (!dw->desc_pool) {
+		dev_err(chip->dev, "No memory for descriptors dma pool\n");
+		return -ENOMEM;
+	}
+
+	tasklet_init(&dw->tasklet, dw_dma_tasklet, (unsigned long)dw);
+
+	INIT_LIST_HEAD(&dw->dma.channels);
+	for (i = 0; i < nr_channels; i++) {
+		struct dw_dma_chan	*dwc = &dw->chan[i];
+		int			r = nr_channels - i - 1;
+
+		dwc->chan.device = &dw->dma;
+		dma_cookie_init(&dwc->chan);
+		if (pdata->chan_allocation_order == CHAN_ALLOCATION_ASCENDING)
+			list_add_tail(&dwc->chan.device_node,
+					&dw->dma.channels);
+		else
+			list_add(&dwc->chan.device_node, &dw->dma.channels);
+
+		/* 7 is highest priority & 0 is lowest. */
+		if (pdata->chan_priority == CHAN_PRIORITY_ASCENDING)
+			dwc->priority = r;
+		else
+			dwc->priority = i;
+
+		dwc->ch_regs = &__dw_regs(dw)->CHAN[i];
+		spin_lock_init(&dwc->lock);
+		dwc->mask = 1 << i;
+
+		INIT_LIST_HEAD(&dwc->active_list);
+		INIT_LIST_HEAD(&dwc->queue);
+		INIT_LIST_HEAD(&dwc->free_list);
+
+		channel_clear_bit(dw, CH_EN, dwc->mask);
+
+		dwc->direction = DMA_TRANS_NONE;
+		dwc->request_line = ~0;
+
+		/* Hardware configuration */
+		if (autocfg) {
+			unsigned int dwc_params;
+			void __iomem *addr = chip->regs + r * sizeof(u32);
+
+			dwc_params = dma_read_byaddr(addr, DWC_PARAMS);
+
+			dev_dbg(chip->dev, "DWC_PARAMS[%d]: 0x%08x\n", i,
+					   dwc_params);
+
+			/* Decode maximum block size for given channel. The
+			 * stored 4 bit value represents blocks from 0x00 for 3
+			 * up to 0x0a for 4095. */
+			dwc->block_size =
+				(4 << ((max_blk_size >> 4 * i) & 0xf)) - 1;
+			dwc->nollp =
+				(dwc_params >> DWC_PARAMS_MBLK_EN & 0x1) == 0;
+		} else {
+			dwc->block_size = pdata->block_size;
+
+			/* Check if channel supports multi block transfer */
+			channel_writel(dwc, LLP, 0xfffffffc);
+			dwc->nollp =
+				(channel_readl(dwc, LLP) & 0xfffffffc) == 0;
+			channel_writel(dwc, LLP, 0);
+		}
+	}
+
+	/* Clear all interrupts on all channels. */
+	dma_writel(dw, CLEAR.XFER, dw->all_chan_mask);
+	dma_writel(dw, CLEAR.BLOCK, dw->all_chan_mask);
+	dma_writel(dw, CLEAR.SRC_TRAN, dw->all_chan_mask);
+	dma_writel(dw, CLEAR.DST_TRAN, dw->all_chan_mask);
+	dma_writel(dw, CLEAR.ERROR, dw->all_chan_mask);
+
+	dma_cap_set(DMA_MEMCPY, dw->dma.cap_mask);
+	dma_cap_set(DMA_SLAVE, dw->dma.cap_mask);
+	if (pdata->is_private)
+		dma_cap_set(DMA_PRIVATE, dw->dma.cap_mask);
+	dw->dma.dev = chip->dev;
+	dw->dma.device_alloc_chan_resources = dwc_alloc_chan_resources;
+	dw->dma.device_free_chan_resources = dwc_free_chan_resources;
+
+	dw->dma.device_prep_dma_memcpy = dwc_prep_dma_memcpy;
+
+	dw->dma.device_prep_slave_sg = dwc_prep_slave_sg;
+	dw->dma.device_control = dwc_control;
+
+	dw->dma.device_tx_status = dwc_tx_status;
+	dw->dma.device_issue_pending = dwc_issue_pending;
+
+	dma_writel(dw, CFG, DW_CFG_DMA_EN);
+
+	dev_info(chip->dev, "DesignWare DMA Controller, %d channels\n",
+		 nr_channels);
+
+	dma_async_device_register(&dw->dma);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dma_probe);
+
+int dw_dma_remove(struct dw_dma_chip *chip)
+{
+	struct dw_dma		*dw = chip->dw;
+	struct dw_dma_chan	*dwc, *_dwc;
+
+	dw_dma_off(dw);
+	dma_async_device_unregister(&dw->dma);
+
+	tasklet_kill(&dw->tasklet);
+
+	list_for_each_entry_safe(dwc, _dwc, &dw->dma.channels,
+			chan.device_node) {
+		list_del(&dwc->chan.device_node);
+		channel_clear_bit(dw, CH_EN, dwc->mask);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dma_remove);
+
+void dw_dma_shutdown(struct dw_dma_chip *chip)
+{
+	struct dw_dma *dw = chip->dw;
+
+	dw_dma_off(dw);
+	clk_disable_unprepare(dw->clk);
+}
+EXPORT_SYMBOL_GPL(dw_dma_shutdown);
+
+#ifdef CONFIG_PM_SLEEP
+
+int dw_dma_suspend(struct dw_dma_chip *chip)
+{
+	struct dw_dma *dw = chip->dw;
+
+	dw_dma_off(dw);
+	clk_disable_unprepare(dw->clk);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dma_suspend);
+
+int dw_dma_resume(struct dw_dma_chip *chip)
+{
+	struct dw_dma *dw = chip->dw;
+
+	clk_prepare_enable(dw->clk);
+	dma_writel(dw, CFG, DW_CFG_DMA_EN);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_dma_resume);
+
+#endif /* CONFIG_PM_SLEEP */
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Synopsys DesignWare DMA Controller core driver");
+MODULE_AUTHOR("Haavard Skinnemoen (Atmel)");
+MODULE_AUTHOR("Viresh Kumar <viresh.linux@gmail.com>");