dmaengine: driver for the ARM PL080/PL081 PrimeCells v5

This creates a DMAengine driver for the ARM PL080/PL081 PrimeCells
based on the implementation earlier submitted by Peter Pearse.
This is working like a charm for memcpy and slave DMA to the PL011
PrimeCell on the PB11MPCore.

This DMA controller is used in mostly unmodified form in the ARM
RealView and Versatile platforms, in the ST-Ericsson Nomadik, and
in the ST SPEAr platform.

It has been converted to use the header from the Samsung PL080
derivate instead of its own defintions. The Samsungs have a custom
driver in their mach-* folders though, atleast we can share the
register definitions.

Cc: Peter Pearse <peter.pearse@arm.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Alessandro Rubini <rubini@unipv.it>
Acked-by: NViresh Kumar <viresh.kumar@st.com>
Signed-off-by: NLinus Walleij <linus.walleij@stericsson.com>
[GFP_KERNEL to GFP_NOWAIT in pl08x_prep_dma_memcpy]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

drivers/dma/Kconfig

@@ -49,6 +49,14 @@ config INTEL_MID_DMAC
 config ASYNC_TX_DISABLE_CHANNEL_SWITCH
 	bool
 
+config AMBA_PL08X
+	bool "ARM PrimeCell PL080 or PL081 support"
+	depends on ARM_AMBA && EXPERIMENTAL
+	select DMA_ENGINE
+	help
+	  Platform has a PL08x DMAC device
+	  which can provide DMA engine support
+
 config INTEL_IOATDMA
 	tristate "Intel I/OAT DMA support"
 	depends on PCI && X86

drivers/dma/Makefile

@@ -25,3 +25,4 @@ obj-$(CONFIG_TIMB_DMA) += timb_dma.o
 obj-$(CONFIG_STE_DMA40) += ste_dma40.o ste_dma40_ll.o
 obj-$(CONFIG_PL330_DMA) += pl330.o
 obj-$(CONFIG_PCH_DMA) += pch_dma.o
+obj-$(CONFIG_AMBA_PL08X) += amba-pl08x.o

drivers/dma/amba-pl08x.c

+/*
+ * Copyright (c) 2006 ARM Ltd.
+ * Copyright (c) 2010 ST-Ericsson SA
+ *
+ * Author: Peter Pearse <peter.pearse@arm.com>
+ * Author: Linus Walleij <linus.walleij@stericsson.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.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The full GNU General Public License is iin this distribution in the
+ * file called COPYING.
+ *
+ * Documentation: ARM DDI 0196G == PL080
+ * Documentation: ARM DDI 0218E	== PL081
+ *
+ * PL080 & PL081 both have 16 sets of DMA signals that can be routed to
+ * any channel.
+ *
+ * The PL080 has 8 channels available for simultaneous use, and the PL081
+ * has only two channels. So on these DMA controllers the number of channels
+ * and the number of incoming DMA signals are two totally different things.
+ * It is usually not possible to theoretically handle all physical signals,
+ * so a multiplexing scheme with possible denial of use is necessary.
+ *
+ * The PL080 has a dual bus master, PL081 has a single master.
+ *
+ * Memory to peripheral transfer may be visualized as
+ *	Get data from memory to DMAC
+ *	Until no data left
+ *		On burst request from peripheral
+ *			Destination burst from DMAC to peripheral
+ *			Clear burst request
+ *	Raise terminal count interrupt
+ *
+ * For peripherals with a FIFO:
+ * Source      burst size == half the depth of the peripheral FIFO
+ * Destination burst size == the depth of the peripheral FIFO
+ *
+ * (Bursts are irrelevant for mem to mem transfers - there are no burst
+ * signals, the DMA controller will simply facilitate its AHB master.)
+ *
+ * ASSUMES default (little) endianness for DMA transfers
+ *
+ * Only DMAC flow control is implemented
+ *
+ * Global TODO:
+ * - Break out common code from arch/arm/mach-s3c64xx and share
+ */
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/dmapool.h>
+#include <linux/amba/bus.h>
+#include <linux/dmaengine.h>
+#include <linux/amba/pl08x.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <asm/hardware/pl080.h>
+#include <asm/dma.h>
+#include <asm/mach/dma.h>
+#include <asm/atomic.h>
+#include <asm/processor.h>
+#include <asm/cacheflush.h>
+
+#define DRIVER_NAME	"pl08xdmac"
+
+/**
+ * struct vendor_data - vendor-specific config parameters
+ * for PL08x derivates
+ * @name: the name of this specific variant
+ * @channels: the number of channels available in this variant
+ * @dualmaster: whether this version supports dual AHB masters
+ * or not.
+ */
+struct vendor_data {
+	char *name;
+	u8 channels;
+	bool dualmaster;
+};
+
+/*
+ * PL08X private data structures
+ * An LLI struct - see pl08x TRM
+ * Note that next uses bit[0] as a bus bit,
+ * start & end do not - their bus bit info
+ * is in cctl
+ */
+struct lli {
+	dma_addr_t src;
+	dma_addr_t dst;
+	dma_addr_t next;
+	u32 cctl;
+};
+
+/**
+ * struct pl08x_driver_data - the local state holder for the PL08x
+ * @slave: slave engine for this instance
+ * @memcpy: memcpy engine for this instance
+ * @base: virtual memory base (remapped) for the PL08x
+ * @adev: the corresponding AMBA (PrimeCell) bus entry
+ * @vd: vendor data for this PL08x variant
+ * @pd: platform data passed in from the platform/machine
+ * @phy_chans: array of data for the physical channels
+ * @pool: a pool for the LLI descriptors
+ * @pool_ctr: counter of LLIs in the pool
+ * @lock: a spinlock for this struct
+ */
+struct pl08x_driver_data {
+	struct dma_device slave;
+	struct dma_device memcpy;
+	void __iomem *base;
+	struct amba_device *adev;
+	struct vendor_data *vd;
+	struct pl08x_platform_data *pd;
+	struct pl08x_phy_chan *phy_chans;
+	struct dma_pool *pool;
+	int pool_ctr;
+	spinlock_t lock;
+};
+
+/*
+ * PL08X specific defines
+ */
+
+/*
+ * Memory boundaries: the manual for PL08x says that the controller
+ * cannot read past a 1KiB boundary, so these defines are used to
+ * create transfer LLIs that do not cross such boundaries.
+ */
+#define PL08X_BOUNDARY_SHIFT		(10)	/* 1KB 0x400 */
+#define PL08X_BOUNDARY_SIZE		(1 << PL08X_BOUNDARY_SHIFT)
+
+/* Minimum period between work queue runs */
+#define PL08X_WQ_PERIODMIN	20
+
+/* Size (bytes) of each LLI buffer allocated for one transfer */
+# define PL08X_LLI_TSFR_SIZE	0x2000
+
+/* Maximimum times we call dma_pool_alloc on this pool without freeing */
+#define PL08X_MAX_ALLOCS	0x40
+#define MAX_NUM_TSFR_LLIS	(PL08X_LLI_TSFR_SIZE/sizeof(struct lli))
+#define PL08X_ALIGN		8
+
+static inline struct pl08x_dma_chan *to_pl08x_chan(struct dma_chan *chan)
+{
+	return container_of(chan, struct pl08x_dma_chan, chan);
+}
+
+/*
+ * Physical channel handling
+ */
+
+/* Whether a certain channel is busy or not */
+static int pl08x_phy_channel_busy(struct pl08x_phy_chan *ch)
+{
+	unsigned int val;
+
+	val = readl(ch->base + PL080_CH_CONFIG);
+	return val & PL080_CONFIG_ACTIVE;
+}
+
+/*
+ * Set the initial DMA register values i.e. those for the first LLI
+ * The next lli pointer and the configuration interrupt bit have
+ * been set when the LLIs were constructed
+ */
+static void pl08x_set_cregs(struct pl08x_driver_data *pl08x,
+			    struct pl08x_phy_chan *ch)
+{
+	/* Wait for channel inactive */
+	while (pl08x_phy_channel_busy(ch))
+		;
+
+	dev_vdbg(&pl08x->adev->dev,
+		"WRITE channel %d: csrc=%08x, cdst=%08x, "
+		 "cctl=%08x, clli=%08x, ccfg=%08x\n",
+		ch->id,
+		ch->csrc,
+		ch->cdst,
+		ch->cctl,
+		ch->clli,
+		ch->ccfg);
+
+	writel(ch->csrc, ch->base + PL080_CH_SRC_ADDR);
+	writel(ch->cdst, ch->base + PL080_CH_DST_ADDR);
+	writel(ch->clli, ch->base + PL080_CH_LLI);
+	writel(ch->cctl, ch->base + PL080_CH_CONTROL);
+	writel(ch->ccfg, ch->base + PL080_CH_CONFIG);
+}
+
+static inline void pl08x_config_phychan_for_txd(struct pl08x_dma_chan *plchan)
+{
+	struct pl08x_channel_data *cd = plchan->cd;
+	struct pl08x_phy_chan *phychan = plchan->phychan;
+	struct pl08x_txd *txd = plchan->at;
+
+	/* Copy the basic control register calculated at transfer config */
+	phychan->csrc = txd->csrc;
+	phychan->cdst = txd->cdst;
+	phychan->clli = txd->clli;
+	phychan->cctl = txd->cctl;
+
+	/* Assign the signal to the proper control registers */
+	phychan->ccfg = cd->ccfg;
+	phychan->ccfg &= ~PL080_CONFIG_SRC_SEL_MASK;
+	phychan->ccfg &= ~PL080_CONFIG_DST_SEL_MASK;
+	/* If it wasn't set from AMBA, ignore it */
+	if (txd->direction == DMA_TO_DEVICE)
+		/* Select signal as destination */
+		phychan->ccfg |=
+			(phychan->signal << PL080_CONFIG_DST_SEL_SHIFT);
+	else if (txd->direction == DMA_FROM_DEVICE)
+		/* Select signal as source */
+		phychan->ccfg |=
+			(phychan->signal << PL080_CONFIG_SRC_SEL_SHIFT);
+	/* Always enable error interrupts */
+	phychan->ccfg |= PL080_CONFIG_ERR_IRQ_MASK;
+	/* Always enable terminal interrupts */
+	phychan->ccfg |= PL080_CONFIG_TC_IRQ_MASK;
+}
+
+/*
+ * Enable the DMA channel
+ * Assumes all other configuration bits have been set
+ * as desired before this code is called
+ */
+static void pl08x_enable_phy_chan(struct pl08x_driver_data *pl08x,
+				  struct pl08x_phy_chan *ch)
+{
+	u32 val;
+
+	/*
+	 * Do not access config register until channel shows as disabled
+	 */
+	while (readl(pl08x->base + PL080_EN_CHAN) & (1 << ch->id))
+		;
+
+	/*
+	 * Do not access config register until channel shows as inactive
+	 */
+	val = readl(ch->base + PL080_CH_CONFIG);
+	while ((val & PL080_CONFIG_ACTIVE) || (val & PL080_CONFIG_ENABLE))
+		val = readl(ch->base + PL080_CH_CONFIG);
+
+	writel(val | PL080_CONFIG_ENABLE, ch->base + PL080_CH_CONFIG);
+}
+
+/*
+ * Overall DMAC remains enabled always.
+ *
+ * Disabling individual channels could lose data.
+ *
+ * Disable the peripheral DMA after disabling the DMAC
+ * in order to allow the DMAC FIFO to drain, and
+ * hence allow the channel to show inactive
+ *
+ */
+static void pl08x_pause_phy_chan(struct pl08x_phy_chan *ch)
+{
+	u32 val;
+
+	/* Set the HALT bit and wait for the FIFO to drain */
+	val = readl(ch->base + PL080_CH_CONFIG);
+	val |= PL080_CONFIG_HALT;
+	writel(val, ch->base + PL080_CH_CONFIG);
+
+	/* Wait for channel inactive */
+	while (pl08x_phy_channel_busy(ch))
+		;
+}
+
+static void pl08x_resume_phy_chan(struct pl08x_phy_chan *ch)
+{
+	u32 val;
+
+	/* Clear the HALT bit */
+	val = readl(ch->base + PL080_CH_CONFIG);
+	val &= ~PL080_CONFIG_HALT;
+	writel(val, ch->base + PL080_CH_CONFIG);
+}
+
+
+/* Stops the channel */
+static void pl08x_stop_phy_chan(struct pl08x_phy_chan *ch)
+{
+	u32 val;
+
+	pl08x_pause_phy_chan(ch);
+
+	/* Disable channel */
+	val = readl(ch->base + PL080_CH_CONFIG);
+	val &= ~PL080_CONFIG_ENABLE;
+	val &= ~PL080_CONFIG_ERR_IRQ_MASK;
+	val &= ~PL080_CONFIG_TC_IRQ_MASK;
+	writel(val, ch->base + PL080_CH_CONFIG);
+}
+
+static inline u32 get_bytes_in_cctl(u32 cctl)
+{
+	/* The source width defines the number of bytes */
+	u32 bytes = cctl & PL080_CONTROL_TRANSFER_SIZE_MASK;
+
+	switch (cctl >> PL080_CONTROL_SWIDTH_SHIFT) {
+	case PL080_WIDTH_8BIT:
+		break;
+	case PL080_WIDTH_16BIT:
+		bytes *= 2;
+		break;
+	case PL080_WIDTH_32BIT:
+		bytes *= 4;
+		break;
+	}
+	return bytes;
+}
+
+/* The channel should be paused when calling this */
+static u32 pl08x_getbytes_chan(struct pl08x_dma_chan *plchan)
+{
+	struct pl08x_phy_chan *ch;
+	struct pl08x_txd *txdi = NULL;
+	struct pl08x_txd *txd;
+	unsigned long flags;
+	u32 bytes = 0;
+
+	spin_lock_irqsave(&plchan->lock, flags);
+
+	ch = plchan->phychan;
+	txd = plchan->at;
+
+	/*
+	 * Next follow the LLIs to get the number of pending bytes in the
+	 * currently active transaction.
+	 */
+	if (ch && txd) {
+		struct lli *llis_va = txd->llis_va;
+		struct lli *llis_bus = (struct lli *) txd->llis_bus;
+		u32 clli = readl(ch->base + PL080_CH_LLI);
+
+		/* First get the bytes in the current active LLI */
+		bytes = get_bytes_in_cctl(readl(ch->base + PL080_CH_CONTROL));
+
+		if (clli) {
+			int i = 0;
+
+			/* Forward to the LLI pointed to by clli */
+			while ((clli != (u32) &(llis_bus[i])) &&
+			       (i < MAX_NUM_TSFR_LLIS))
+				i++;
+
+			while (clli) {
+				bytes += get_bytes_in_cctl(llis_va[i].cctl);
+				/*
+				 * A clli of 0x00000000 will terminate the
+				 * LLI list
+				 */
+				clli = llis_va[i].next;
+				i++;
+			}
+		}
+	}
+
+	/* Sum up all queued transactions */
+	if (!list_empty(&plchan->desc_list)) {
+		list_for_each_entry(txdi, &plchan->desc_list, node) {
+			bytes += txdi->len;
+		}
+
+	}
+
+	spin_unlock_irqrestore(&plchan->lock, flags);
+
+	return bytes;
+}
+
+/*
+ * Allocate a physical channel for a virtual channel
+ */
+static struct pl08x_phy_chan *
+pl08x_get_phy_channel(struct pl08x_driver_data *pl08x,
+		      struct pl08x_dma_chan *virt_chan)
+{
+	struct pl08x_phy_chan *ch = NULL;
+	unsigned long flags;
+	int i;
+
+	/*
+	 * Try to locate a physical channel to be used for
+	 * this transfer. If all are taken return NULL and
+	 * the requester will have to cope by using some fallback
+	 * PIO mode or retrying later.
+	 */
+	for (i = 0; i < pl08x->vd->channels; i++) {
+		ch = &pl08x->phy_chans[i];
+
+		spin_lock_irqsave(&ch->lock, flags);
+
+		if (!ch->serving) {
+			ch->serving = virt_chan;
+			ch->signal = -1;
+			spin_unlock_irqrestore(&ch->lock, flags);
+			break;
+		}
+
+		spin_unlock_irqrestore(&ch->lock, flags);
+	}
+
+	if (i == pl08x->vd->channels) {
+		/* No physical channel available, cope with it */
+		return NULL;
+	}
+
+	return ch;
+}
+
+static inline void pl08x_put_phy_channel(struct pl08x_driver_data *pl08x,
+					 struct pl08x_phy_chan *ch)
+{
+	unsigned long flags;
+
+	/* Stop the channel and clear its interrupts */
+	pl08x_stop_phy_chan(ch);
+	writel((1 << ch->id), pl08x->base + PL080_ERR_CLEAR);
+	writel((1 << ch->id), pl08x->base + PL080_TC_CLEAR);
+
+	/* Mark it as free */
+	spin_lock_irqsave(&ch->lock, flags);
+	ch->serving = NULL;
+	spin_unlock_irqrestore(&ch->lock, flags);
+}
+
+/*
+ * LLI handling
+ */
+
+static inline unsigned int pl08x_get_bytes_for_cctl(unsigned int coded)
+{
+	switch (coded) {
+	case PL080_WIDTH_8BIT:
+		return 1;
+	case PL080_WIDTH_16BIT:
+		return 2;
+	case PL080_WIDTH_32BIT:
+		return 4;
+	default:
+		break;
+	}
+	BUG();
+	return 0;
+}
+
+static inline u32 pl08x_cctl_bits(u32 cctl, u8 srcwidth, u8 dstwidth,
+				  u32 tsize)
+{
+	u32 retbits = cctl;
+
+	/* Remove all src, dst and transfersize bits */
+	retbits &= ~PL080_CONTROL_DWIDTH_MASK;
+	retbits &= ~PL080_CONTROL_SWIDTH_MASK;
+	retbits &= ~PL080_CONTROL_TRANSFER_SIZE_MASK;
+
+	/* Then set the bits according to the parameters */
+	switch (srcwidth) {
+	case 1:
+		retbits |= PL080_WIDTH_8BIT << PL080_CONTROL_SWIDTH_SHIFT;
+		break;
+	case 2:
+		retbits |= PL080_WIDTH_16BIT << PL080_CONTROL_SWIDTH_SHIFT;
+		break;
+	case 4:
+		retbits |= PL080_WIDTH_32BIT << PL080_CONTROL_SWIDTH_SHIFT;
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	switch (dstwidth) {
+	case 1:
+		retbits |= PL080_WIDTH_8BIT << PL080_CONTROL_DWIDTH_SHIFT;
+		break;
+	case 2:
+		retbits |= PL080_WIDTH_16BIT << PL080_CONTROL_DWIDTH_SHIFT;
+		break;
+	case 4:
+		retbits |= PL080_WIDTH_32BIT << PL080_CONTROL_DWIDTH_SHIFT;
+		break;
+	default:
+		BUG();
+		break;
+	}
+
+	retbits |= tsize << PL080_CONTROL_TRANSFER_SIZE_SHIFT;
+	return retbits;
+}
+
+/*
+ * Autoselect a master bus to use for the transfer
+ * this prefers the destination bus if both available
+ * if fixed address on one bus the other will be chosen
+ */
+void pl08x_choose_master_bus(struct pl08x_bus_data *src_bus,
+	struct pl08x_bus_data *dst_bus, struct pl08x_bus_data **mbus,
+	struct pl08x_bus_data **sbus, u32 cctl)
+{
+	if (!(cctl & PL080_CONTROL_DST_INCR)) {
+		*mbus = src_bus;
+		*sbus = dst_bus;
+	} else if (!(cctl & PL080_CONTROL_SRC_INCR)) {
+		*mbus = dst_bus;
+		*sbus = src_bus;
+	} else {
+		if (dst_bus->buswidth == 4) {
+			*mbus = dst_bus;
+			*sbus = src_bus;
+		} else if (src_bus->buswidth == 4) {
+			*mbus = src_bus;
+			*sbus = dst_bus;
+		} else if (dst_bus->buswidth == 2) {
+			*mbus = dst_bus;
+			*sbus = src_bus;
+		} else if (src_bus->buswidth == 2) {
+			*mbus = src_bus;
+			*sbus = dst_bus;
+		} else {
+			/* src_bus->buswidth == 1 */
+			*mbus = dst_bus;
+			*sbus = src_bus;
+		}
+	}
+}
+
+/*
+ * Fills in one LLI for a certain transfer descriptor
+ * and advance the counter
+ */
+int pl08x_fill_lli_for_desc(struct pl08x_driver_data *pl08x,
+			    struct pl08x_txd *txd, int num_llis, int len,
+			    u32 cctl, u32 *remainder)
+{
+	struct lli *llis_va = txd->llis_va;
+	struct lli *llis_bus = (struct lli *) txd->llis_bus;
+
+	BUG_ON(num_llis >= MAX_NUM_TSFR_LLIS);
+
+	llis_va[num_llis].cctl		= cctl;
+	llis_va[num_llis].src		= txd->srcbus.addr;
+	llis_va[num_llis].dst		= txd->dstbus.addr;
+
+	/*
+	 * On versions with dual masters, you can optionally AND on
+	 * PL080_LLI_LM_AHB2 to the LLI to tell the hardware to read
+	 * in new LLIs with that controller, but we always try to
+	 * choose AHB1 to point into memory. The idea is to have AHB2
+	 * fixed on the peripheral and AHB1 messing around in the
+	 * memory. So we don't manipulate this bit currently.
+	 */
+
+	llis_va[num_llis].next =
+		(dma_addr_t)((u32) &(llis_bus[num_llis + 1]));
+
+	if (cctl & PL080_CONTROL_SRC_INCR)
+		txd->srcbus.addr += len;
+	if (cctl & PL080_CONTROL_DST_INCR)
+		txd->dstbus.addr += len;
+
+	*remainder -= len;
+
+	return num_llis + 1;
+}
+
+/*
+ * Return number of bytes to fill to boundary, or len
+ */
+static inline u32 pl08x_pre_boundary(u32 addr, u32 len)
+{
+	u32 boundary;
+
+	boundary = ((addr >> PL08X_BOUNDARY_SHIFT) + 1)
+		<< PL08X_BOUNDARY_SHIFT;
+
+	if (boundary < addr + len)
+		return boundary - addr;
+	else
+		return len;
+}
+
+/*
+ * This fills in the table of LLIs for the transfer descriptor
+ * Note that we assume we never have to change the burst sizes
+ * Return 0 for error
+ */
+static int pl08x_fill_llis_for_desc(struct pl08x_driver_data *pl08x,
+			      struct pl08x_txd *txd)
+{
+	struct pl08x_channel_data *cd = txd->cd;
+	struct pl08x_bus_data *mbus, *sbus;
+	u32 remainder;
+	int num_llis = 0;
+	u32 cctl;
+	int max_bytes_per_lli;
+	int total_bytes = 0;
+	struct lli *llis_va;
+	struct lli *llis_bus;
+
+	if (!txd) {
+		dev_err(&pl08x->adev->dev, "%s no descriptor\n", __func__);
+		return 0;
+	}
+
+	txd->llis_va = dma_pool_alloc(pl08x->pool, GFP_NOWAIT,
+				      &txd->llis_bus);
+	if (!txd->llis_va) {
+		dev_err(&pl08x->adev->dev, "%s no memory for llis\n", __func__);
+		return 0;
+	}
+
+	pl08x->pool_ctr++;
+
+	/*
+	 * Initialize bus values for this transfer
+	 * from the passed optimal values
+	 */
+	if (!cd) {
+		dev_err(&pl08x->adev->dev, "%s no channel data\n", __func__);
+		return 0;
+	}
+
+	/* Get the default CCTL from the platform data */
+	cctl = cd->cctl;
+
+	/*
+	 * On the PL080 we have two bus masters and we
+	 * should select one for source and one for
+	 * destination. We try to use AHB2 for the
+	 * bus which does not increment (typically the
+	 * peripheral) else we just choose something.
+	 */
+	cctl &= ~(PL080_CONTROL_DST_AHB2 | PL080_CONTROL_SRC_AHB2);
+	if (pl08x->vd->dualmaster) {
+		if (cctl & PL080_CONTROL_SRC_INCR)
+			/* Source increments, use AHB2 for destination */
+			cctl |= PL080_CONTROL_DST_AHB2;
+		else if (cctl & PL080_CONTROL_DST_INCR)
+			/* Destination increments, use AHB2 for source */
+			cctl |= PL080_CONTROL_SRC_AHB2;
+		else
+			/* Just pick something, source AHB1 dest AHB2 */
+			cctl |= PL080_CONTROL_DST_AHB2;
+	}
+
+	/* Find maximum width of the source bus */
+	txd->srcbus.maxwidth =
+		pl08x_get_bytes_for_cctl((cctl & PL080_CONTROL_SWIDTH_MASK) >>
+				       PL080_CONTROL_SWIDTH_SHIFT);
+
+	/* Find maximum width of the destination bus */
+	txd->dstbus.maxwidth =
+		pl08x_get_bytes_for_cctl((cctl & PL080_CONTROL_DWIDTH_MASK) >>
+				       PL080_CONTROL_DWIDTH_SHIFT);
+
+	/* Set up the bus widths to the maximum */
+	txd->srcbus.buswidth = txd->srcbus.maxwidth;
+	txd->dstbus.buswidth = txd->dstbus.maxwidth;
+	dev_vdbg(&pl08x->adev->dev,
+		 "%s source bus is %d bytes wide, dest bus is %d bytes wide\n",
+		 __func__, txd->srcbus.buswidth, txd->dstbus.buswidth);
+
+
+	/*
+	 * Bytes transferred == tsize * MIN(buswidths), not max(buswidths)
+	 */
+	max_bytes_per_lli = min(txd->srcbus.buswidth, txd->dstbus.buswidth) *
+		PL080_CONTROL_TRANSFER_SIZE_MASK;
+	dev_vdbg(&pl08x->adev->dev,
+		 "%s max bytes per lli = %d\n",
+		 __func__, max_bytes_per_lli);
+
+	/* We need to count this down to zero */
+	remainder = txd->len;
+	dev_vdbg(&pl08x->adev->dev,
+		 "%s remainder = %d\n",
+		 __func__, remainder);
+
+	/*
+	 * Choose bus to align to
+	 * - prefers destination bus if both available
+	 * - if fixed address on one bus chooses other
+	 * - modifies cctl to choose an apropriate master
+	 */
+	pl08x_choose_master_bus(&txd->srcbus, &txd->dstbus,
+				&mbus, &sbus, cctl);
+
+
+	/*
+	 * The lowest bit of the LLI register
+	 * is also used to indicate which master to
+	 * use for reading the LLIs.
+	 */
+
+	if (txd->len < mbus->buswidth) {
+		/*
+		 * Less than a bus width available
+		 * - send as single bytes
+		 */
+		while (remainder) {
+			dev_vdbg(&pl08x->adev->dev,
+				 "%s single byte LLIs for a transfer of "
+				 "less than a bus width (remain %08x)\n",
+				 __func__, remainder);
+			cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
+			num_llis =
+				pl08x_fill_lli_for_desc(pl08x, txd, num_llis, 1,
+					cctl, &remainder);
+			total_bytes++;
+		}
+	} else {
+		/*
+		 *  Make one byte LLIs until master bus is aligned
+		 *  - slave will then be aligned also
+		 */
+		while ((mbus->addr) % (mbus->buswidth)) {
+			dev_vdbg(&pl08x->adev->dev,
+				"%s adjustment lli for less than bus width "
+				 "(remain %08x)\n",
+				 __func__, remainder);
+			cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
+			num_llis = pl08x_fill_lli_for_desc
+				(pl08x, txd, num_llis, 1, cctl, &remainder);
+			total_bytes++;
+		}
+
+		/*
+		 *  Master now aligned
+		 * - if slave is not then we must set its width down
+		 */
+		if (sbus->addr % sbus->buswidth) {
+			dev_dbg(&pl08x->adev->dev,
+				"%s set down bus width to one byte\n",
+				 __func__);
+
+			sbus->buswidth = 1;
+		}
+
+		/*
+		 * Make largest possible LLIs until less than one bus
+		 * width left
+		 */
+		while (remainder > (mbus->buswidth - 1)) {
+			int lli_len, target_len;
+			int tsize;
+			int odd_bytes;
+
+			/*
+			 * If enough left try to send max possible,
+			 * otherwise try to send the remainder
+			 */
+			target_len = remainder;
+			if (remainder > max_bytes_per_lli)
+				target_len = max_bytes_per_lli;
+
+			/*
+			 * Set bus lengths for incrementing busses
+			 * to number of bytes which fill to next memory
+			 * boundary
+			 */
+			if (cctl & PL080_CONTROL_SRC_INCR)
+				txd->srcbus.fill_bytes =
+					pl08x_pre_boundary(
+						txd->srcbus.addr,
+						remainder);
+			else
+				txd->srcbus.fill_bytes =
+					max_bytes_per_lli;
+
+			if (cctl & PL080_CONTROL_DST_INCR)
+				txd->dstbus.fill_bytes =
+					pl08x_pre_boundary(
+						txd->dstbus.addr,
+						remainder);
+			else
+				txd->dstbus.fill_bytes =
+						max_bytes_per_lli;
+
+			/*
+			 *  Find the nearest
+			 */
+			lli_len	= min(txd->srcbus.fill_bytes,
+				txd->dstbus.fill_bytes);
+
+			BUG_ON(lli_len > remainder);
+
+			if (lli_len <= 0) {
+				dev_err(&pl08x->adev->dev,
+					"%s lli_len is %d, <= 0\n",
+						__func__, lli_len);
+				return 0;
+			}
+
+			if (lli_len == target_len) {
+				/*
+				 * Can send what we wanted
+				 */
+				/*
+				 *  Maintain alignment
+				 */
+				lli_len	= (lli_len/mbus->buswidth) *
+							mbus->buswidth;
+				odd_bytes = 0;
+			} else {
+				/*
+				 * So now we know how many bytes to transfer
+				 * to get to the nearest boundary
+				 * The next lli will past the boundary
+				 * - however we may be working to a boundary
+				 *   on the slave bus
+				 *   We need to ensure the master stays aligned
+				 */
+				odd_bytes = lli_len % mbus->buswidth;
+				/*
+				 * - and that we are working in multiples
+				 *   of the bus widths
+				 */
+				lli_len -= odd_bytes;
+
+			}
+
+			if (lli_len) {
+				/*
+				 * Check against minimum bus alignment:
+				 * Calculate actual transfer size in relation
+				 * to bus width an get a maximum remainder of
+				 * the smallest bus width - 1
+				 */
+				/* FIXME: use round_down()? */
+				tsize = lli_len / min(mbus->buswidth,
+						      sbus->buswidth);
+				lli_len	= tsize * min(mbus->buswidth,
+						      sbus->buswidth);
+
+				if (target_len != lli_len) {
+					dev_vdbg(&pl08x->adev->dev,
+					"%s can't send what we want. Desired %08x, lli of %08x bytes in txd of %08x\n",
+					__func__, target_len, lli_len, txd->len);
+				}
+
+				cctl = pl08x_cctl_bits(cctl,
+						       txd->srcbus.buswidth,
+						       txd->dstbus.buswidth,
+						       tsize);
+
+				dev_vdbg(&pl08x->adev->dev,
+					"%s fill lli with single lli chunk of size %08x (remainder %08x)\n",
+					__func__, lli_len, remainder);
+				num_llis = pl08x_fill_lli_for_desc(pl08x, txd,
+						num_llis, lli_len, cctl,
+						&remainder);
+				total_bytes += lli_len;
+			}
+
+
+			if (odd_bytes) {
+				/*
+				 * Creep past the boundary,
+				 * maintaining master alignment
+				 */
+				int j;
+				for (j = 0; (j < mbus->buswidth)
+						&& (remainder); j++) {
+					cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
+					dev_vdbg(&pl08x->adev->dev,
+						"%s align with boundardy, single byte (remain %08x)\n",
+						__func__, remainder);
+					num_llis =
+						pl08x_fill_lli_for_desc(pl08x,
+							txd, num_llis, 1,
+							cctl, &remainder);
+					total_bytes++;
+				}
+			}
+		}
+
+		/*
+		 * Send any odd bytes
+		 */
+		if (remainder < 0) {
+			dev_err(&pl08x->adev->dev, "%s remainder not fitted 0x%08x bytes\n",
+					__func__, remainder);
+			return 0;
+		}
+
+		while (remainder) {
+			cctl = pl08x_cctl_bits(cctl, 1, 1, 1);
+			dev_vdbg(&pl08x->adev->dev,
+				"%s align with boundardy, single odd byte (remain %d)\n",
+				__func__, remainder);
+			num_llis = pl08x_fill_lli_for_desc(pl08x, txd, num_llis,
+					1, cctl, &remainder);
+			total_bytes++;
+		}
+	}
+	if (total_bytes != txd->len) {
+		dev_err(&pl08x->adev->dev,
+			"%s size of encoded lli:s don't match total txd, transferred 0x%08x from size 0x%08x\n",
+			__func__, total_bytes, txd->len);
+		return 0;
+	}
+
+	if (num_llis >= MAX_NUM_TSFR_LLIS) {
+		dev_err(&pl08x->adev->dev,
+			"%s need to increase MAX_NUM_TSFR_LLIS from 0x%08x\n",
+			__func__, (u32) MAX_NUM_TSFR_LLIS);
+		return 0;
+	}
+	/*
+	 * Decide whether this is a loop or a terminated transfer
+	 */
+	llis_va = txd->llis_va;
+	llis_bus = (struct lli *) txd->llis_bus;
+
+	if (cd->circular_buffer) {
+		/*
+		 * Loop the circular buffer so that the next element
+		 * points back to the beginning of the LLI.
+		 */
+		llis_va[num_llis - 1].next =
+			(dma_addr_t)((unsigned int)&(llis_bus[0]));
+	} else {
+		/*
+		 * On non-circular buffers, the final LLI terminates
+		 * the LLI.
+		 */
+		llis_va[num_llis - 1].next = 0;
+		/*
+		 * The final LLI element shall also fire an interrupt
+		 */
+		llis_va[num_llis - 1].cctl |= PL080_CONTROL_TC_IRQ_EN;
+	}
+
+	/* Now store the channel register values */
+	txd->csrc = llis_va[0].src;
+	txd->cdst = llis_va[0].dst;
+	if (num_llis > 1)
+		txd->clli = llis_va[0].next;
+	else
+		txd->clli = 0;
+
+	txd->cctl = llis_va[0].cctl;
+	/* ccfg will be set at physical channel allocation time */
+
+#ifdef VERBOSE_DEBUG
+	{
+		int i;
+
+		for (i = 0; i < num_llis; i++) {
+			dev_vdbg(&pl08x->adev->dev,
+				 "lli %d @%p: csrc=%08x, cdst=%08x, cctl=%08x, clli=%08x\n",
+				 i,
+				 &llis_va[i],
+				 llis_va[i].src,
+				 llis_va[i].dst,
+				 llis_va[i].cctl,
+				 llis_va[i].next
+				);
+		}
+	}
+#endif
+
+	return num_llis;
+}
+
+/* You should call this with the struct pl08x lock held */
+static void pl08x_free_txd(struct pl08x_driver_data *pl08x,
+			   struct pl08x_txd *txd)
+{
+	if (!txd)
+		dev_err(&pl08x->adev->dev,
+			"%s no descriptor to free\n",
+			__func__);
+
+	/* Free the LLI */
+	dma_pool_free(pl08x->pool, txd->llis_va,
+		      txd->llis_bus);
+
+	pl08x->pool_ctr--;
+
+	kfree(txd);
+}
+
+static void pl08x_free_txd_list(struct pl08x_driver_data *pl08x,
+				struct pl08x_dma_chan *plchan)
+{
+	struct pl08x_txd *txdi = NULL;
+	struct pl08x_txd *next;
+
+	if (!list_empty(&plchan->desc_list)) {
+		list_for_each_entry_safe(txdi,
+					 next, &plchan->desc_list, node) {
+			list_del(&txdi->node);
+			pl08x_free_txd(pl08x, txdi);
+		}
+
+	}
+}
+
+/*
+ * The DMA ENGINE API
+ */
+static int pl08x_alloc_chan_resources(struct dma_chan *chan)
+{
+	return 0;
+}
+
+static void pl08x_free_chan_resources(struct dma_chan *chan)
+{
+}
+
+/*
+ * This should be called with the channel plchan->lock held
+ */
+static int prep_phy_channel(struct pl08x_dma_chan *plchan,
+			    struct pl08x_txd *txd)
+{
+	struct pl08x_driver_data *pl08x = plchan->host;
+	struct pl08x_phy_chan *ch;
+	int ret;
+
+	/* Check if we already have a channel */
+	if (plchan->phychan)
+		return 0;
+
+	ch = pl08x_get_phy_channel(pl08x, plchan);
+	if (!ch) {
+		/* No physical channel available, cope with it */
+		dev_dbg(&pl08x->adev->dev, "no physical channel available for xfer on %s\n", plchan->name);
+		return -EBUSY;
+	}
+
+	/*
+	 * OK we have a physical channel: for memcpy() this is all we
+	 * need, but for slaves the physical signals may be muxed!
+	 * Can the platform allow us to use this channel?
+	 */
+	if (plchan->slave &&
+	    ch->signal < 0 &&
+	    pl08x->pd->get_signal) {
+		ret = pl08x->pd->get_signal(plchan);
+		if (ret < 0) {
+			dev_dbg(&pl08x->adev->dev,
+				"unable to use physical channel %d for transfer on %s due to platform restrictions\n",
+				ch->id, plchan->name);
+			/* Release physical channel & return */
+			pl08x_put_phy_channel(pl08x, ch);
+			return -EBUSY;
+		}
+		ch->signal = ret;
+	}
+
+	dev_dbg(&pl08x->adev->dev, "allocated physical channel %d and signal %d for xfer on %s\n",
+		 ch->id,
+		 ch->signal,
+		 plchan->name);
+
+	plchan->phychan = ch;
+
+	return 0;
+}
+
+static dma_cookie_t pl08x_tx_submit(struct dma_async_tx_descriptor *tx)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(tx->chan);
+
+	atomic_inc(&plchan->last_issued);
+	tx->cookie = atomic_read(&plchan->last_issued);
+	/* This unlock follows the lock in the prep() function */
+	spin_unlock_irqrestore(&plchan->lock, plchan->lockflags);
+
+	return tx->cookie;
+}
+
+static struct dma_async_tx_descriptor *pl08x_prep_dma_interrupt(
+		struct dma_chan *chan, unsigned long flags)
+{
+	struct dma_async_tx_descriptor *retval = NULL;
+
+	return retval;
+}
+
+/*
+ * Code accessing dma_async_is_complete() in a tight loop
+ * may give problems - could schedule where indicated.
+ * If slaves are relying on interrupts to signal completion this
+ * function must not be called with interrupts disabled
+ */
+static enum dma_status
+pl08x_dma_tx_status(struct dma_chan *chan,
+		    dma_cookie_t cookie,
+		    struct dma_tx_state *txstate)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	dma_cookie_t last_used;
+	dma_cookie_t last_complete;
+	enum dma_status ret;
+	u32 bytesleft = 0;
+
+	last_used = atomic_read(&plchan->last_issued);
+	last_complete = plchan->lc;
+
+	ret = dma_async_is_complete(cookie, last_complete, last_used);
+	if (ret == DMA_SUCCESS) {
+		dma_set_tx_state(txstate, last_complete, last_used, 0);
+		return ret;
+	}
+
+	/*
+	 * schedule(); could be inserted here
+	 */
+
+	/*
+	 * This cookie not complete yet
+	 */
+	last_used = atomic_read(&plchan->last_issued);
+	last_complete = plchan->lc;
+
+	/* Get number of bytes left in the active transactions and queue */
+	bytesleft = pl08x_getbytes_chan(plchan);
+
+	dma_set_tx_state(txstate, last_complete, last_used,
+			 bytesleft);
+
+	if (plchan->state == PL08X_CHAN_PAUSED)
+		return DMA_PAUSED;
+
+	/* Whether waiting or running, we're in progress */
+	return DMA_IN_PROGRESS;
+}
+
+/* PrimeCell DMA extension */
+struct burst_table {
+	int burstwords;
+	u32 reg;
+};
+
+static const struct burst_table burst_sizes[] = {
+	{
+		.burstwords = 256,
+		.reg = (PL080_BSIZE_256 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_256 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 128,
+		.reg = (PL080_BSIZE_128 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_128 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 64,
+		.reg = (PL080_BSIZE_64 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_64 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 32,
+		.reg = (PL080_BSIZE_32 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_32 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 16,
+		.reg = (PL080_BSIZE_16 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_16 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 8,
+		.reg = (PL080_BSIZE_8 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_8 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 4,
+		.reg = (PL080_BSIZE_4 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_4 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+	{
+		.burstwords = 1,
+		.reg = (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT),
+	},
+};
+
+static void dma_set_runtime_config(struct dma_chan *chan,
+			       struct dma_slave_config *config)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+	struct pl08x_channel_data *cd = plchan->cd;
+	enum dma_slave_buswidth addr_width;
+	u32 maxburst;
+	u32 cctl = 0;
+	/* Mask out all except src and dst channel */
+	u32 ccfg = cd->ccfg & 0x000003DEU;
+	int i = 0;
+
+	/* Transfer direction */
+	plchan->runtime_direction = config->direction;
+	if (config->direction == DMA_TO_DEVICE) {
+		plchan->runtime_addr = config->dst_addr;
+		cctl |= PL080_CONTROL_SRC_INCR;
+		ccfg |= PL080_FLOW_MEM2PER << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+		addr_width = config->dst_addr_width;
+		maxburst = config->dst_maxburst;
+	} else if (config->direction == DMA_FROM_DEVICE) {
+		plchan->runtime_addr = config->src_addr;
+		cctl |= PL080_CONTROL_DST_INCR;
+		ccfg |= PL080_FLOW_PER2MEM << PL080_CONFIG_FLOW_CONTROL_SHIFT;
+		addr_width = config->src_addr_width;
+		maxburst = config->src_maxburst;
+	} else {
+		dev_err(&pl08x->adev->dev,
+			"bad runtime_config: alien transfer direction\n");
+		return;
+	}
+
+	switch (addr_width) {
+	case DMA_SLAVE_BUSWIDTH_1_BYTE:
+		cctl |= (PL080_WIDTH_8BIT << PL080_CONTROL_SWIDTH_SHIFT) |
+			(PL080_WIDTH_8BIT << PL080_CONTROL_DWIDTH_SHIFT);
+		break;
+	case DMA_SLAVE_BUSWIDTH_2_BYTES:
+		cctl |= (PL080_WIDTH_16BIT << PL080_CONTROL_SWIDTH_SHIFT) |
+			(PL080_WIDTH_16BIT << PL080_CONTROL_DWIDTH_SHIFT);
+		break;
+	case DMA_SLAVE_BUSWIDTH_4_BYTES:
+		cctl |= (PL080_WIDTH_32BIT << PL080_CONTROL_SWIDTH_SHIFT) |
+			(PL080_WIDTH_32BIT << PL080_CONTROL_DWIDTH_SHIFT);
+		break;
+	default:
+		dev_err(&pl08x->adev->dev,
+			"bad runtime_config: alien address width\n");
+		return;
+	}
+
+	/*
+	 * Now decide on a maxburst:
+	 * If this channel will only request single transfers, set
+	 * this down to ONE element.
+	 */
+	if (plchan->cd->single) {
+		cctl |= (PL080_BSIZE_1 << PL080_CONTROL_SB_SIZE_SHIFT) |
+			(PL080_BSIZE_1 << PL080_CONTROL_DB_SIZE_SHIFT);
+	} else {
+		while (i < ARRAY_SIZE(burst_sizes)) {
+			if (burst_sizes[i].burstwords <= maxburst)
+				break;
+			i++;
+		}
+		cctl |= burst_sizes[i].reg;
+	}
+
+	/* Access the cell in privileged mode, non-bufferable, non-cacheable */
+	cctl &= ~PL080_CONTROL_PROT_MASK;
+	cctl |= PL080_CONTROL_PROT_SYS;
+
+	/* Modify the default channel data to fit PrimeCell request */
+	cd->cctl = cctl;
+	cd->ccfg = ccfg;
+
+	dev_dbg(&pl08x->adev->dev,
+		"configured channel %s (%s) for %s, data width %d, "
+		"maxburst %d words, LE, CCTL=%08x, CCFG=%08x\n",
+		dma_chan_name(chan), plchan->name,
+		(config->direction == DMA_FROM_DEVICE) ? "RX" : "TX",
+		addr_width,
+		maxburst,
+		cctl, ccfg);
+}
+
+/*
+ * Slave transactions callback to the slave device to allow
+ * synchronization of slave DMA signals with the DMAC enable
+ */
+static void pl08x_issue_pending(struct dma_chan *chan)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+	unsigned long flags;
+
+	spin_lock_irqsave(&plchan->lock, flags);
+	/* Something is already active */
+	if (plchan->at) {
+			spin_unlock_irqrestore(&plchan->lock, flags);
+			return;
+	}
+
+	/* Didn't get a physical channel so waiting for it ... */
+	if (plchan->state == PL08X_CHAN_WAITING)
+		return;
+
+	/* Take the first element in the queue and execute it */
+	if (!list_empty(&plchan->desc_list)) {
+		struct pl08x_txd *next;
+
+		next = list_first_entry(&plchan->desc_list,
+					struct pl08x_txd,
+					node);
+		list_del(&next->node);
+		plchan->at = next;
+		plchan->state = PL08X_CHAN_RUNNING;
+
+		/* Configure the physical channel for the active txd */
+		pl08x_config_phychan_for_txd(plchan);
+		pl08x_set_cregs(pl08x, plchan->phychan);
+		pl08x_enable_phy_chan(pl08x, plchan->phychan);
+	}
+
+	spin_unlock_irqrestore(&plchan->lock, flags);
+}
+
+static int pl08x_prep_channel_resources(struct pl08x_dma_chan *plchan,
+					struct pl08x_txd *txd)
+{
+	int num_llis;
+	struct pl08x_driver_data *pl08x = plchan->host;
+	int ret;
+
+	num_llis = pl08x_fill_llis_for_desc(pl08x, txd);
+
+	if (!num_llis)
+		return -EINVAL;
+
+	spin_lock_irqsave(&plchan->lock, plchan->lockflags);
+
+	/*
+	 * If this device is not using a circular buffer then
+	 * queue this new descriptor for transfer.
+	 * The descriptor for a circular buffer continues
+	 * to be used until the channel is freed.
+	 */
+	if (txd->cd->circular_buffer)
+		dev_err(&pl08x->adev->dev,
+			"%s attempting to queue a circular buffer\n",
+			__func__);
+	else
+		list_add_tail(&txd->node,
+			      &plchan->desc_list);
+
+	/*
+	 * See if we already have a physical channel allocated,
+	 * else this is the time to try to get one.
+	 */
+	ret = prep_phy_channel(plchan, txd);
+	if (ret) {
+		/*
+		 * No physical channel available, we will
+		 * stack up the memcpy channels until there is a channel
+		 * available to handle it whereas slave transfers may
+		 * have been denied due to platform channel muxing restrictions
+		 * and since there is no guarantee that this will ever be
+		 * resolved, and since the signal must be aquired AFTER
+		 * aquiring the physical channel, we will let them be NACK:ed
+		 * with -EBUSY here. The drivers can alway retry the prep()
+		 * call if they are eager on doing this using DMA.
+		 */
+		if (plchan->slave) {
+			pl08x_free_txd_list(pl08x, plchan);
+			spin_unlock_irqrestore(&plchan->lock, plchan->lockflags);
+			return -EBUSY;
+		}
+		/* Do this memcpy whenever there is a channel ready */
+		plchan->state = PL08X_CHAN_WAITING;
+		plchan->waiting = txd;
+	} else
+		/*
+		 * Else we're all set, paused and ready to roll,
+		 * status will switch to PL08X_CHAN_RUNNING when
+		 * we call issue_pending(). If there is something
+		 * running on the channel already we don't change
+		 * its state.
+		 */
+		if (plchan->state == PL08X_CHAN_IDLE)
+			plchan->state = PL08X_CHAN_PAUSED;
+
+	/*
+	 * Notice that we leave plchan->lock locked on purpose:
+	 * it will be unlocked in the subsequent tx_submit()
+	 * call. This is a consequence of the current API.
+	 */
+
+	return 0;
+}
+
+/*
+ * Initialize a descriptor to be used by memcpy submit
+ */
+static struct dma_async_tx_descriptor *pl08x_prep_dma_memcpy(
+		struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+	struct pl08x_txd *txd;
+	int ret;
+
+	txd = kzalloc(sizeof(struct pl08x_txd), GFP_NOWAIT);
+	if (!txd) {
+		dev_err(&pl08x->adev->dev,
+			"%s no memory for descriptor\n", __func__);
+		return NULL;
+	}
+
+	dma_async_tx_descriptor_init(&txd->tx, chan);
+	txd->direction = DMA_NONE;
+	txd->srcbus.addr = src;
+	txd->dstbus.addr = dest;
+
+	/* Set platform data for m2m */
+	txd->cd = &pl08x->pd->memcpy_channel;
+	/* Both to be incremented or the code will break */
+	txd->cd->cctl |= PL080_CONTROL_SRC_INCR | PL080_CONTROL_DST_INCR;
+	txd->tx.tx_submit = pl08x_tx_submit;
+	txd->tx.callback = NULL;
+	txd->tx.callback_param = NULL;
+	txd->len = len;
+
+	INIT_LIST_HEAD(&txd->node);
+	ret = pl08x_prep_channel_resources(plchan, txd);
+	if (ret)
+		return NULL;
+	/*
+	 * NB: the channel lock is held at this point so tx_submit()
+	 * must be called in direct succession.
+	 */
+
+	return &txd->tx;
+}
+
+struct dma_async_tx_descriptor *pl08x_prep_slave_sg(
+		struct dma_chan *chan, struct scatterlist *sgl,
+		unsigned int sg_len, enum dma_data_direction direction,
+		unsigned long flags)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+	struct pl08x_txd *txd;
+	int ret;
+
+	/*
+	 * Current implementation ASSUMES only one sg
+	 */
+	if (sg_len != 1) {
+		dev_err(&pl08x->adev->dev, "%s prepared too long sglist\n",
+			__func__);
+		BUG();
+	}
+
+	dev_dbg(&pl08x->adev->dev, "%s prepare transaction of %d bytes from %s\n",
+		__func__, sgl->length, plchan->name);
+
+	txd = kzalloc(sizeof(struct pl08x_txd), GFP_NOWAIT);
+	if (!txd) {
+		dev_err(&pl08x->adev->dev, "%s no txd\n", __func__);
+		return NULL;
+	}
+
+	dma_async_tx_descriptor_init(&txd->tx, chan);
+
+	if (direction != plchan->runtime_direction)
+		dev_err(&pl08x->adev->dev, "%s DMA setup does not match "
+			"the direction configured for the PrimeCell\n",
+			__func__);
+
+	/*
+	 * Set up addresses, the PrimeCell configured address
+	 * will take precedence since this may configure the
+	 * channel target address dynamically at runtime.
+	 */
+	txd->direction = direction;
+	if (direction == DMA_TO_DEVICE) {
+		txd->srcbus.addr = sgl->dma_address;
+		if (plchan->runtime_addr)
+			txd->dstbus.addr = plchan->runtime_addr;
+		else
+			txd->dstbus.addr = plchan->cd->addr;
+	} else if (direction == DMA_FROM_DEVICE) {
+		if (plchan->runtime_addr)
+			txd->srcbus.addr = plchan->runtime_addr;
+		else
+			txd->srcbus.addr = plchan->cd->addr;
+		txd->dstbus.addr = sgl->dma_address;
+	} else {
+		dev_err(&pl08x->adev->dev,
+			"%s direction unsupported\n", __func__);
+		return NULL;
+	}
+	txd->cd = plchan->cd;
+	txd->tx.tx_submit = pl08x_tx_submit;
+	txd->tx.callback = NULL;
+	txd->tx.callback_param = NULL;
+	txd->len = sgl->length;
+	INIT_LIST_HEAD(&txd->node);
+
+	ret = pl08x_prep_channel_resources(plchan, txd);
+	if (ret)
+		return NULL;
+	/*
+	 * NB: the channel lock is held at this point so tx_submit()
+	 * must be called in direct succession.
+	 */
+
+	return &txd->tx;
+}
+
+static int pl08x_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
+			 unsigned long arg)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	struct pl08x_driver_data *pl08x = plchan->host;
+	unsigned long flags;
+	int ret = 0;
+
+	/* Controls applicable to inactive channels */
+	if (cmd == DMA_SLAVE_CONFIG) {
+		dma_set_runtime_config(chan,
+				       (struct dma_slave_config *)
+				       arg);
+		return 0;
+	}
+
+	/*
+	 * Anything succeeds on channels with no physical allocation and
+	 * no queued transfers.
+	 */
+	spin_lock_irqsave(&plchan->lock, flags);
+	if (!plchan->phychan && !plchan->at) {
+		spin_unlock_irqrestore(&plchan->lock, flags);
+		return 0;
+	}
+
+	switch (cmd) {
+	case DMA_TERMINATE_ALL:
+		plchan->state = PL08X_CHAN_IDLE;
+
+		if (plchan->phychan) {
+			pl08x_stop_phy_chan(plchan->phychan);
+
+			/*
+			 * Mark physical channel as free and free any slave
+			 * signal
+			 */
+			if ((plchan->phychan->signal >= 0) &&
+			    pl08x->pd->put_signal) {
+				pl08x->pd->put_signal(plchan);
+				plchan->phychan->signal = -1;
+			}
+			pl08x_put_phy_channel(pl08x, plchan->phychan);
+			plchan->phychan = NULL;
+		}
+		/* Stop any pending tasklet */
+		tasklet_disable(&plchan->tasklet);
+		/* Dequeue jobs and free LLIs */
+		if (plchan->at) {
+			pl08x_free_txd(pl08x, plchan->at);
+			plchan->at = NULL;
+		}
+		/* Dequeue jobs not yet fired as well */
+		pl08x_free_txd_list(pl08x, plchan);
+		break;
+	case DMA_PAUSE:
+		pl08x_pause_phy_chan(plchan->phychan);
+		plchan->state = PL08X_CHAN_PAUSED;
+		break;
+	case DMA_RESUME:
+		pl08x_resume_phy_chan(plchan->phychan);
+		plchan->state = PL08X_CHAN_RUNNING;
+		break;
+	default:
+		/* Unknown command */
+		ret = -ENXIO;
+		break;
+	}
+
+	spin_unlock_irqrestore(&plchan->lock, flags);
+
+	return ret;
+}
+
+bool pl08x_filter_id(struct dma_chan *chan, void *chan_id)
+{
+	struct pl08x_dma_chan *plchan = to_pl08x_chan(chan);
+	char *name = chan_id;
+
+	/* Check that the channel is not taken! */
+	if (!strcmp(plchan->name, name))
+		return true;
+
+	return false;
+}
+
+/*
+ * Just check that the device is there and active
+ * TODO: turn this bit on/off depending on the number of
+ * physical channels actually used, if it is zero... well
+ * shut it off. That will save some power. Cut the clock
+ * at the same time.
+ */
+static void pl08x_ensure_on(struct pl08x_driver_data *pl08x)
+{
+	u32 val;
+
+	val = readl(pl08x->base + PL080_CONFIG);
+	val &= ~(PL080_CONFIG_M2_BE | PL080_CONFIG_M1_BE | PL080_CONFIG_ENABLE);
+	/* We implictly clear bit 1 and that means little-endian mode */
+	val |= PL080_CONFIG_ENABLE;
+	writel(val, pl08x->base + PL080_CONFIG);
+}
+
+static void pl08x_tasklet(unsigned long data)
+{
+	struct pl08x_dma_chan *plchan = (struct pl08x_dma_chan *) data;
+	struct pl08x_phy_chan *phychan = plchan->phychan;
+	struct pl08x_driver_data *pl08x = plchan->host;
+
+	if (!plchan)
+		BUG();
+
+	spin_lock(&plchan->lock);
+
+	if (plchan->at) {
+		dma_async_tx_callback callback =
+			plchan->at->tx.callback;
+		void *callback_param =
+			plchan->at->tx.callback_param;
+
+		/*
+		 * Update last completed
+		 */
+		plchan->lc =
+			(plchan->at->tx.cookie);
+
+		/*
+		 * Callback to signal completion
+		 */
+		if (callback)
+			callback(callback_param);
+
+		/*
+		 * Device callbacks should NOT clear
+		 * the current transaction on the channel
+		 * Linus: sometimes they should?
+		 */
+		if (!plchan->at)
+			BUG();
+
+		/*
+		 * Free the descriptor if it's not for a device
+		 * using a circular buffer
+		 */
+		if (!plchan->at->cd->circular_buffer) {
+			pl08x_free_txd(pl08x, plchan->at);
+			plchan->at = NULL;
+		}
+		/*
+		 * else descriptor for circular
+		 * buffers only freed when
+		 * client has disabled dma
+		 */
+	}
+	/*
+	 * If a new descriptor is queued, set it up
+	 * plchan->at is NULL here
+	 */
+	if (!list_empty(&plchan->desc_list)) {
+		struct pl08x_txd *next;
+
+		next = list_first_entry(&plchan->desc_list,
+					struct pl08x_txd,
+					node);
+		list_del(&next->node);
+		plchan->at = next;
+		/* Configure the physical channel for the next txd */
+		pl08x_config_phychan_for_txd(plchan);
+		pl08x_set_cregs(pl08x, plchan->phychan);
+		pl08x_enable_phy_chan(pl08x, plchan->phychan);
+	} else {
+		struct pl08x_dma_chan *waiting = NULL;
+
+		/*
+		 * No more jobs, so free up the physical channel
+		 * Free any allocated signal on slave transfers too
+		 */
+		if ((phychan->signal >= 0) && pl08x->pd->put_signal) {
+			pl08x->pd->put_signal(plchan);
+			phychan->signal = -1;
+		}
+		pl08x_put_phy_channel(pl08x, phychan);
+		plchan->phychan = NULL;
+		plchan->state = PL08X_CHAN_IDLE;
+
+		/*
+		 * And NOW before anyone else can grab that free:d
+		 * up physical channel, see if there is some memcpy
+		 * pending that seriously needs to start because of
+		 * being stacked up while we were choking the
+		 * physical channels with data.
+		 */
+		list_for_each_entry(waiting, &pl08x->memcpy.channels,
+				    chan.device_node) {
+		  if (waiting->state == PL08X_CHAN_WAITING &&
+			    waiting->waiting != NULL) {
+				int ret;
+
+				/* This should REALLY not fail now */
+				ret = prep_phy_channel(waiting,
+						       waiting->waiting);
+				BUG_ON(ret);
+				waiting->state = PL08X_CHAN_RUNNING;
+				waiting->waiting = NULL;
+				pl08x_issue_pending(&waiting->chan);
+				break;
+			}
+		}
+	}
+
+	spin_unlock(&plchan->lock);
+}
+
+static irqreturn_t pl08x_irq(int irq, void *dev)
+{
+	struct pl08x_driver_data *pl08x = dev;
+	u32 mask = 0;
+	u32 val;
+	int i;
+
+	val = readl(pl08x->base + PL080_ERR_STATUS);
+	if (val) {
+		/*
+		 * An error interrupt (on one or more channels)
+		 */
+		dev_err(&pl08x->adev->dev,
+			"%s error interrupt, register value 0x%08x\n",
+				__func__, val);
+		/*
+		 * Simply clear ALL PL08X error interrupts,
+		 * regardless of channel and cause
+		 * FIXME: should be 0x00000003 on PL081 really.
+		 */
+		writel(0x000000FF, pl08x->base + PL080_ERR_CLEAR);
+	}
+	val = readl(pl08x->base + PL080_INT_STATUS);
+	for (i = 0; i < pl08x->vd->channels; i++) {
+		if ((1 << i) & val) {
+			/* Locate physical channel */
+			struct pl08x_phy_chan *phychan = &pl08x->phy_chans[i];
+			struct pl08x_dma_chan *plchan = phychan->serving;
+
+			/* Schedule tasklet on this channel */
+			tasklet_schedule(&plchan->tasklet);
+
+			mask |= (1 << i);
+		}
+	}
+	/*
+	 * Clear only the terminal interrupts on channels we processed
+	 */
+	writel(mask, pl08x->base + PL080_TC_CLEAR);
+
+	return mask ? IRQ_HANDLED : IRQ_NONE;
+}
+
+/*
+ * Initialise the DMAC memcpy/slave channels.
+ * Make a local wrapper to hold required data
+ */
+static int pl08x_dma_init_virtual_channels(struct pl08x_driver_data *pl08x,
+					   struct dma_device *dmadev,
+					   unsigned int channels,
+					   bool slave)
+{
+	struct pl08x_dma_chan *chan;
+	int i;
+
+	INIT_LIST_HEAD(&dmadev->channels);
+	/*
+	 * Register as many many memcpy as we have physical channels,
+	 * we won't always be able to use all but the code will have
+	 * to cope with that situation.
+	 */
+	for (i = 0; i < channels; i++) {
+		chan = kzalloc(sizeof(struct pl08x_dma_chan), GFP_KERNEL);
+		if (!chan) {
+			dev_err(&pl08x->adev->dev,
+				"%s no memory for channel\n", __func__);
+			return -ENOMEM;
+		}
+
+		chan->host = pl08x;
+		chan->state = PL08X_CHAN_IDLE;
+
+		if (slave) {
+			chan->slave = true;
+			chan->name = pl08x->pd->slave_channels[i].bus_id;
+			chan->cd = &pl08x->pd->slave_channels[i];
+		} else {
+			chan->cd = &pl08x->pd->memcpy_channel;
+			chan->name = kasprintf(GFP_KERNEL, "memcpy%d", i);
+			if (!chan->name) {
+				kfree(chan);
+				return -ENOMEM;
+			}
+		}
+		dev_info(&pl08x->adev->dev,
+			 "initialize virtual channel \"%s\"\n",
+			 chan->name);
+
+		chan->chan.device = dmadev;
+		atomic_set(&chan->last_issued, 0);
+		chan->lc = atomic_read(&chan->last_issued);
+
+		spin_lock_init(&chan->lock);
+		INIT_LIST_HEAD(&chan->desc_list);
+		tasklet_init(&chan->tasklet, pl08x_tasklet,
+			     (unsigned long) chan);
+
+		list_add_tail(&chan->chan.device_node, &dmadev->channels);
+	}
+	dev_info(&pl08x->adev->dev, "initialized %d virtual %s channels\n",
+		 i, slave ? "slave" : "memcpy");
+	return i;
+}
+
+static void pl08x_free_virtual_channels(struct dma_device *dmadev)
+{
+	struct pl08x_dma_chan *chan = NULL;
+	struct pl08x_dma_chan *next;
+
+	list_for_each_entry_safe(chan,
+				 next, &dmadev->channels, chan.device_node) {
+		list_del(&chan->chan.device_node);
+		kfree(chan);
+	}
+}
+
+#ifdef CONFIG_DEBUG_FS
+static const char *pl08x_state_str(enum pl08x_dma_chan_state state)
+{
+	switch (state) {
+	case PL08X_CHAN_IDLE:
+		return "idle";
+	case PL08X_CHAN_RUNNING:
+		return "running";
+	case PL08X_CHAN_PAUSED:
+		return "paused";
+	case PL08X_CHAN_WAITING:
+		return "waiting";
+	default:
+		break;
+	}
+	return "UNKNOWN STATE";
+}
+
+static int pl08x_debugfs_show(struct seq_file *s, void *data)
+{
+	struct pl08x_driver_data *pl08x = s->private;
+	struct pl08x_dma_chan *chan;
+	struct pl08x_phy_chan *ch;
+	unsigned long flags;
+	int i;
+
+	seq_printf(s, "PL08x physical channels:\n");
+	seq_printf(s, "CHANNEL:\tUSER:\n");
+	seq_printf(s, "--------\t-----\n");
+	for (i = 0; i < pl08x->vd->channels; i++) {
+		struct pl08x_dma_chan *virt_chan;
+
+		ch = &pl08x->phy_chans[i];
+
+		spin_lock_irqsave(&ch->lock, flags);
+		virt_chan = ch->serving;
+
+		seq_printf(s, "%d\t\t%s\n",
+			   ch->id, virt_chan ? virt_chan->name : "(none)");
+
+		spin_unlock_irqrestore(&ch->lock, flags);
+	}
+
+	seq_printf(s, "\nPL08x virtual memcpy channels:\n");
+	seq_printf(s, "CHANNEL:\tSTATE:\n");
+	seq_printf(s, "--------\t------\n");
+	list_for_each_entry(chan, &pl08x->memcpy.channels, chan.device_node) {
+		seq_printf(s, "%s\t\t\%s\n", chan->name,
+			   pl08x_state_str(chan->state));
+	}
+
+	seq_printf(s, "\nPL08x virtual slave channels:\n");
+	seq_printf(s, "CHANNEL:\tSTATE:\n");
+	seq_printf(s, "--------\t------\n");
+	list_for_each_entry(chan, &pl08x->slave.channels, chan.device_node) {
+		seq_printf(s, "%s\t\t\%s\n", chan->name,
+			   pl08x_state_str(chan->state));
+	}
+
+	return 0;
+}
+
+static int pl08x_debugfs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, pl08x_debugfs_show, inode->i_private);
+}
+
+static const struct file_operations pl08x_debugfs_operations = {
+	.open		= pl08x_debugfs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static void init_pl08x_debugfs(struct pl08x_driver_data *pl08x)
+{
+	/* Expose a simple debugfs interface to view all clocks */
+	(void) debugfs_create_file(dev_name(&pl08x->adev->dev), S_IFREG | S_IRUGO,
+				   NULL, pl08x,
+				   &pl08x_debugfs_operations);
+}
+
+#else
+static inline void init_pl08x_debugfs(struct pl08x_driver_data *pl08x)
+{
+}
+#endif
+
+static int pl08x_probe(struct amba_device *adev, struct amba_id *id)
+{
+	struct pl08x_driver_data *pl08x;
+	struct vendor_data *vd = id->data;
+	int ret = 0;
+	int i;
+
+	ret = amba_request_regions(adev, NULL);
+	if (ret)
+		return ret;
+
+	/* Create the driver state holder */
+	pl08x = kzalloc(sizeof(struct pl08x_driver_data), GFP_KERNEL);
+	if (!pl08x) {
+		ret = -ENOMEM;
+		goto out_no_pl08x;
+	}
+
+	/* Initialize memcpy engine */
+	dma_cap_set(DMA_MEMCPY, pl08x->memcpy.cap_mask);
+	pl08x->memcpy.dev = &adev->dev;
+	pl08x->memcpy.device_alloc_chan_resources = pl08x_alloc_chan_resources;
+	pl08x->memcpy.device_free_chan_resources = pl08x_free_chan_resources;
+	pl08x->memcpy.device_prep_dma_memcpy = pl08x_prep_dma_memcpy;
+	pl08x->memcpy.device_prep_dma_interrupt = pl08x_prep_dma_interrupt;
+	pl08x->memcpy.device_tx_status = pl08x_dma_tx_status;
+	pl08x->memcpy.device_issue_pending = pl08x_issue_pending;
+	pl08x->memcpy.device_control = pl08x_control;
+
+	/* Initialize slave engine */
+	dma_cap_set(DMA_SLAVE, pl08x->slave.cap_mask);
+	pl08x->slave.dev = &adev->dev;
+	pl08x->slave.device_alloc_chan_resources = pl08x_alloc_chan_resources;
+	pl08x->slave.device_free_chan_resources = pl08x_free_chan_resources;
+	pl08x->slave.device_prep_dma_interrupt = pl08x_prep_dma_interrupt;
+	pl08x->slave.device_tx_status = pl08x_dma_tx_status;
+	pl08x->slave.device_issue_pending = pl08x_issue_pending;
+	pl08x->slave.device_prep_slave_sg = pl08x_prep_slave_sg;
+	pl08x->slave.device_control = pl08x_control;
+
+	/* Get the platform data */
+	pl08x->pd = dev_get_platdata(&adev->dev);
+	if (!pl08x->pd) {
+		dev_err(&adev->dev, "no platform data supplied\n");
+		goto out_no_platdata;
+	}
+
+	/* Assign useful pointers to the driver state */
+	pl08x->adev = adev;
+	pl08x->vd = vd;
+
+	/* A DMA memory pool for LLIs, align on 1-byte boundary */
+	pl08x->pool = dma_pool_create(DRIVER_NAME, &pl08x->adev->dev,
+			PL08X_LLI_TSFR_SIZE, PL08X_ALIGN, 0);
+	if (!pl08x->pool) {
+		ret = -ENOMEM;
+		goto out_no_lli_pool;
+	}
+
+	spin_lock_init(&pl08x->lock);
+
+	pl08x->base = ioremap(adev->res.start, resource_size(&adev->res));
+	if (!pl08x->base) {
+		ret = -ENOMEM;
+		goto out_no_ioremap;
+	}
+
+	/* Turn on the PL08x */
+	pl08x_ensure_on(pl08x);
+
+	/*
+	 * Attach the interrupt handler
+	 */
+	writel(0x000000FF, pl08x->base + PL080_ERR_CLEAR);
+	writel(0x000000FF, pl08x->base + PL080_TC_CLEAR);
+
+	ret = request_irq(adev->irq[0], pl08x_irq, IRQF_DISABLED,
+			  vd->name, pl08x);
+	if (ret) {
+		dev_err(&adev->dev, "%s failed to request interrupt %d\n",
+			__func__, adev->irq[0]);
+		goto out_no_irq;
+	}
+
+	/* Initialize physical channels */
+	pl08x->phy_chans = kmalloc((vd->channels * sizeof(struct pl08x_phy_chan)),
+			GFP_KERNEL);
+	if (!pl08x->phy_chans) {
+		dev_err(&adev->dev, "%s failed to allocate "
+			"physical channel holders\n",
+			__func__);
+		goto out_no_phychans;
+	}
+
+	for (i = 0; i < vd->channels; i++) {
+		struct pl08x_phy_chan *ch = &pl08x->phy_chans[i];
+
+		ch->id = i;
+		ch->base = pl08x->base + PL080_Cx_BASE(i);
+		spin_lock_init(&ch->lock);
+		ch->serving = NULL;
+		ch->signal = -1;
+		dev_info(&adev->dev,
+			 "physical channel %d is %s\n", i,
+			 pl08x_phy_channel_busy(ch) ? "BUSY" : "FREE");
+	}
+
+	/* Register as many memcpy channels as there are physical channels */
+	ret = pl08x_dma_init_virtual_channels(pl08x, &pl08x->memcpy,
+					      pl08x->vd->channels, false);
+	if (ret <= 0) {
+		dev_warn(&pl08x->adev->dev,
+			 "%s failed to enumerate memcpy channels - %d\n",
+			 __func__, ret);
+		goto out_no_memcpy;
+	}
+	pl08x->memcpy.chancnt = ret;
+
+	/* Register slave channels */
+	ret = pl08x_dma_init_virtual_channels(pl08x, &pl08x->slave,
+					      pl08x->pd->num_slave_channels,
+					      true);
+	if (ret <= 0) {
+		dev_warn(&pl08x->adev->dev,
+			"%s failed to enumerate slave channels - %d\n",
+				__func__, ret);
+		goto out_no_slave;
+	}
+	pl08x->slave.chancnt = ret;
+
+	ret = dma_async_device_register(&pl08x->memcpy);
+	if (ret) {
+		dev_warn(&pl08x->adev->dev,
+			"%s failed to register memcpy as an async device - %d\n",
+			__func__, ret);
+		goto out_no_memcpy_reg;
+	}
+
+	ret = dma_async_device_register(&pl08x->slave);
+	if (ret) {
+		dev_warn(&pl08x->adev->dev,
+			"%s failed to register slave as an async device - %d\n",
+			__func__, ret);
+		goto out_no_slave_reg;
+	}
+
+	amba_set_drvdata(adev, pl08x);
+	init_pl08x_debugfs(pl08x);
+	dev_info(&pl08x->adev->dev, "ARM(R) %s DMA block initialized @%08x\n",
+		vd->name, adev->res.start);
+	return 0;
+
+out_no_slave_reg:
+	dma_async_device_unregister(&pl08x->memcpy);
+out_no_memcpy_reg:
+	pl08x_free_virtual_channels(&pl08x->slave);
+out_no_slave:
+	pl08x_free_virtual_channels(&pl08x->memcpy);
+out_no_memcpy:
+	kfree(pl08x->phy_chans);
+out_no_phychans:
+	free_irq(adev->irq[0], pl08x);
+out_no_irq:
+	iounmap(pl08x->base);
+out_no_ioremap:
+	dma_pool_destroy(pl08x->pool);
+out_no_lli_pool:
+out_no_platdata:
+	kfree(pl08x);
+out_no_pl08x:
+	amba_release_regions(adev);
+	return ret;
+}
+
+/* PL080 has 8 channels and the PL080 have just 2 */
+static struct vendor_data vendor_pl080 = {
+	.name = "PL080",
+	.channels = 8,
+	.dualmaster = true,
+};
+
+static struct vendor_data vendor_pl081 = {
+	.name = "PL081",
+	.channels = 2,
+	.dualmaster = false,
+};
+
+static struct amba_id pl08x_ids[] = {
+	/* PL080 */
+	{
+		.id	= 0x00041080,
+		.mask	= 0x000fffff,
+		.data	= &vendor_pl080,
+	},
+	/* PL081 */
+	{
+		.id	= 0x00041081,
+		.mask	= 0x000fffff,
+		.data	= &vendor_pl081,
+	},
+	/* Nomadik 8815 PL080 variant */
+	{
+		.id	= 0x00280880,
+		.mask	= 0x00ffffff,
+		.data	= &vendor_pl080,
+	},
+	{ 0, 0 },
+};
+
+static struct amba_driver pl08x_amba_driver = {
+	.drv.name	= DRIVER_NAME,
+	.id_table	= pl08x_ids,
+	.probe		= pl08x_probe,
+};
+
+static int __init pl08x_init(void)
+{
+	int retval;
+	retval = amba_driver_register(&pl08x_amba_driver);
+	if (retval)
+		printk(KERN_WARNING DRIVER_NAME
+		       "failed to register as an amba device (%d)\n",
+		       retval);
+	return retval;
+}
+subsys_initcall(pl08x_init);

include/linux/amba/pl08x.h

+/*
+ * linux/amba/pl08x.h - ARM PrimeCell DMA Controller driver
+ *
+ * Copyright (C) 2005 ARM Ltd
+ * Copyright (C) 2010 ST-Ericsson SA
+ *
+ * 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.
+ *
+ * pl08x information required by platform code
+ *
+ * Please credit ARM.com
+ * Documentation: ARM DDI 0196D
+ *
+ */
+
+#ifndef AMBA_PL08X_H
+#define AMBA_PL08X_H
+
+/* We need sizes of structs from this header */
+#include <linux/dmaengine.h>
+#include <linux/interrupt.h>
+
+/**
+ * struct pl08x_channel_data - data structure to pass info between
+ * platform and PL08x driver regarding channel configuration
+ * @bus_id: name of this device channel, not just a device name since
+ * devices may have more than one channel e.g. "foo_tx"
+ * @min_signal: the minimum DMA signal number to be muxed in for this
+ * channel (for platforms supporting muxed signals). If you have
+ * static assignments, make sure this is set to the assigned signal
+ * number, PL08x have 16 possible signals in number 0 thru 15 so
+ * when these are not enough they often get muxed (in hardware)
+ * disabling simultaneous use of the same channel for two devices.
+ * @max_signal: the maximum DMA signal number to be muxed in for
+ * the channel. Set to the same as min_signal for
+ * devices with static assignments
+ * @muxval: a number usually used to poke into some mux regiser to
+ * mux in the signal to this channel
+ * @cctl_opt: default options for the channel control register
+ * @addr: source/target address in physical memory for this DMA channel,
+ * can be the address of a FIFO register for burst requests for example.
+ * This can be left undefined if the PrimeCell API is used for configuring
+ * this.
+ * @circular_buffer: whether the buffer passed in is circular and
+ * shall simply be looped round round (like a record baby round
+ * round round round)
+ * @single: the device connected to this channel will request single
+ * DMA transfers, not bursts. (Bursts are default.)
+ */
+struct pl08x_channel_data {
+	char *bus_id;
+	int min_signal;
+	int max_signal;
+	u32 muxval;
+	u32 cctl;
+	u32 ccfg;
+	dma_addr_t addr;
+	bool circular_buffer;
+	bool single;
+};
+
+/**
+ * Struct pl08x_bus_data - information of source or destination
+ * busses for a transfer
+ * @addr: current address
+ * @maxwidth: the maximum width of a transfer on this bus
+ * @buswidth: the width of this bus in bytes: 1, 2 or 4
+ * @fill_bytes: bytes required to fill to the next bus memory
+ * boundary
+ */
+struct pl08x_bus_data {
+	dma_addr_t addr;
+	u8 maxwidth;
+	u8 buswidth;
+	u32 fill_bytes;
+};
+
+/**
+ * struct pl08x_phy_chan - holder for the physical channels
+ * @id: physical index to this channel
+ * @lock: a lock to use when altering an instance of this struct
+ * @signal: the physical signal (aka channel) serving this
+ * physical channel right now
+ * @serving: the virtual channel currently being served by this
+ * physical channel
+ */
+struct pl08x_phy_chan {
+	unsigned int id;
+	void __iomem *base;
+	spinlock_t lock;
+	int signal;
+	struct pl08x_dma_chan *serving;
+	u32 csrc;
+	u32 cdst;
+	u32 clli;
+	u32 cctl;
+	u32 ccfg;
+};
+
+/**
+ * struct pl08x_txd - wrapper for struct dma_async_tx_descriptor
+ * @llis_bus: DMA memory address (physical) start for the LLIs
+ * @llis_va: virtual memory address start for the LLIs
+ */
+struct pl08x_txd {
+	struct dma_async_tx_descriptor tx;
+	struct list_head node;
+	enum dma_data_direction	direction;
+	struct pl08x_bus_data srcbus;
+	struct pl08x_bus_data dstbus;
+	int len;
+	dma_addr_t llis_bus;
+	void *llis_va;
+	struct pl08x_channel_data *cd;
+	bool active;
+	/*
+	 * Settings to be put into the physical channel when we
+	 * trigger this txd
+	 */
+	u32 csrc;
+	u32 cdst;
+	u32 clli;
+	u32 cctl;
+};
+
+/**
+ * struct pl08x_dma_chan_state - holds the PL08x specific virtual
+ * channel states
+ * @PL08X_CHAN_IDLE: the channel is idle
+ * @PL08X_CHAN_RUNNING: the channel has allocated a physical transport
+ * channel and is running a transfer on it
+ * @PL08X_CHAN_PAUSED: the channel has allocated a physical transport
+ * channel, but the transfer is currently paused
+ * @PL08X_CHAN_WAITING: the channel is waiting for a physical transport
+ * channel to become available (only pertains to memcpy channels)
+ */
+enum pl08x_dma_chan_state {
+	PL08X_CHAN_IDLE,
+	PL08X_CHAN_RUNNING,
+	PL08X_CHAN_PAUSED,
+	PL08X_CHAN_WAITING,
+};
+
+/**
+ * struct pl08x_dma_chan - this structure wraps a DMA ENGINE channel
+ * @chan: wrappped abstract channel
+ * @phychan: the physical channel utilized by this channel, if there is one
+ * @tasklet: tasklet scheduled by the IRQ to handle actual work etc
+ * @name: name of channel
+ * @cd: channel platform data
+ * @runtime_addr: address for RX/TX according to the runtime config
+ * @runtime_direction: current direction of this channel according to
+ * runtime config
+ * @lc: last completed transaction on this channel
+ * @desc_list: queued transactions pending on this channel
+ * @at: active transaction on this channel
+ * @lockflags: sometimes we let a lock last between two function calls,
+ * especially prep/submit, and then we need to store the IRQ flags
+ * in the channel state, here
+ * @lock: a lock for this channel data
+ * @host: a pointer to the host (internal use)
+ * @state: whether the channel is idle, paused, running etc
+ * @slave: whether this channel is a device (slave) or for memcpy
+ * @waiting: a TX descriptor on this channel which is waiting for
+ * a physical channel to become available
+ */
+struct pl08x_dma_chan {
+	struct dma_chan chan;
+	struct pl08x_phy_chan *phychan;
+	struct tasklet_struct tasklet;
+	char *name;
+	struct pl08x_channel_data *cd;
+	dma_addr_t runtime_addr;
+	enum dma_data_direction	runtime_direction;
+	atomic_t last_issued;
+	dma_cookie_t lc;
+	struct list_head desc_list;
+	struct pl08x_txd *at;
+	unsigned long lockflags;
+	spinlock_t lock;
+	void *host;
+	enum pl08x_dma_chan_state state;
+	bool slave;
+	struct pl08x_txd *waiting;
+};
+
+/**
+ * struct pl08x_platform_data - the platform configuration for the
+ * PL08x PrimeCells.
+ * @slave_channels: the channels defined for the different devices on the
+ * platform, all inclusive, including multiplexed channels. The available
+ * physical channels will be multiplexed around these signals as they
+ * are requested, just enumerate all possible channels.
+ * @get_signal: request a physical signal to be used for a DMA
+ * transfer immediately: if there is some multiplexing or similar blocking
+ * the use of the channel the transfer can be denied by returning
+ * less than zero, else it returns the allocated signal number
+ * @put_signal: indicate to the platform that this physical signal is not
+ * running any DMA transfer and multiplexing can be recycled
+ * @bus_bit_lli: Bit[0] of the address indicated which AHB bus master the
+ * LLI addresses are on 0/1 Master 1/2.
+ */
+struct pl08x_platform_data {
+	struct pl08x_channel_data *slave_channels;
+	unsigned int num_slave_channels;
+	struct pl08x_channel_data memcpy_channel;
+	int (*get_signal)(struct pl08x_dma_chan *);
+	void (*put_signal)(struct pl08x_dma_chan *);
+};
+
+#ifdef CONFIG_AMBA_PL08X
+bool pl08x_filter_id(struct dma_chan *chan, void *chan_id);
+#else
+static inline bool pl08x_filter_id(struct dma_chan *chan, void *chan_id)
+{
+	return false;
+}
+#endif
+
+#endif	/* AMBA_PL08X_H */