S3C: DMA: Add api driver for PL330

Latest Samsung SoCs have one or more PL330 as their DMACs. This patch
implements the S3C DMA API for PL330 core driver.

The design has been kept as generic as possible while keeping effort to
add support for new SoCs to the minimum possible level.

Some of the salient features of this driver are:-
 o  Automatic scheduling of client requests onto DMAC if more than
    one DMAC can reach the peripheral. Factors, such as current load
    and number of exclusive but inactive peripherals that are
    supported by the DMAC, are used to decide suitability of a DMAC
    for a particular client.
 o  CIRCULAR buffer option is supported.
 o  The driver scales transparently with the number of DMACs and total
    peripherals in the platform, since all peripherals are added to
    the peripheral pool and DMACs to the controller pool.

For most conservative use of memory, smallest driver size and best
performance, we don't employ legacy data structures of the S3C DMA API.
That should not have any affect since those data structures are completely
invisible to the DMA clients.

Signed-off-by: Jassi Brar <jassi.brar@samsung.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

5 files changed, 1342 insertions, 0 deletions

diff --git a/arch/arm/plat-samsung/Kconfig b/arch/arm/plat-samsung/Kconfig
index d552c65fa1b0..78b8b89b4620 100644
--- a/arch/arm/plat-samsung/Kconfig
+++ b/arch/arm/plat-samsung/Kconfig
@@ -198,6 +198,12 @@ config S3C_DMA
 	help
 	  Internal configuration for S3C DMA core
 
+config S3C_PL330_DMA
+	bool
+	select PL330
+	help
+	  S3C DMA API Driver for PL330 DMAC.
+
 comment "Power management"
 
 config SAMSUNG_PM_DEBUG
diff --git a/arch/arm/plat-samsung/Makefile b/arch/arm/plat-samsung/Makefile
index 22c89d08f6e5..05718a36d746 100644
--- a/arch/arm/plat-samsung/Makefile
+++ b/arch/arm/plat-samsung/Makefile
@@ -45,6 +45,8 @@ obj-$(CONFIG_S3C_DEV_NAND)	+= dev-nand.o
 
 obj-$(CONFIG_S3C_DMA)		+= dma.o
 
+obj-$(CONFIG_S3C_PL330_DMA)	+= s3c-pl330.o
+
 # PM support
 
 obj-$(CONFIG_PM)		+= pm.o
diff --git a/arch/arm/plat-samsung/include/plat/s3c-dma-pl330.h b/arch/arm/plat-samsung/include/plat/s3c-dma-pl330.h
new file mode 100644
index 000000000000..5fe6721b57f7
--- /dev/null
+++ b/arch/arm/plat-samsung/include/plat/s3c-dma-pl330.h
@@ -0,0 +1,78 @@
+/*
+ * Copyright (C) 2010 Samsung Electronics Co. Ltd.
+ *	Jaswinder Singh <jassi.brar@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef	__S3C_DMA_PL330_H_
+#define	__S3C_DMA_PL330_H_
+
+#define S3C2410_DMAF_AUTOSTART		(1 << 0)
+#define S3C2410_DMAF_CIRCULAR		(1 << 1)
+
+/*
+ * PL330 can assign any channel to communicate with
+ * any of the peripherals attched to the DMAC.
+ * For the sake of consistency across client drivers,
+ * We keep the channel names unchanged and only add
+ * missing peripherals are added.
+ * Order is not important since S3C PL330 API driver
+ * use these just as IDs.
+ */
+enum dma_ch {
+	DMACH_UART0_RX,
+	DMACH_UART0_TX,
+	DMACH_UART1_RX,
+	DMACH_UART1_TX,
+	DMACH_UART2_RX,
+	DMACH_UART2_TX,
+	DMACH_UART3_RX,
+	DMACH_UART3_TX,
+	DMACH_IRDA,
+	DMACH_I2S0_RX,
+	DMACH_I2S0_TX,
+	DMACH_I2S0S_TX,
+	DMACH_I2S1_RX,
+	DMACH_I2S1_TX,
+	DMACH_I2S2_RX,
+	DMACH_I2S2_TX,
+	DMACH_SPI0_RX,
+	DMACH_SPI0_TX,
+	DMACH_SPI1_RX,
+	DMACH_SPI1_TX,
+	DMACH_SPI2_RX,
+	DMACH_SPI2_TX,
+	DMACH_AC97_MICIN,
+	DMACH_AC97_PCMIN,
+	DMACH_AC97_PCMOUT,
+	DMACH_EXTERNAL,
+	DMACH_PWM,
+	DMACH_SPDIF,
+	DMACH_HSI_RX,
+	DMACH_HSI_TX,
+	DMACH_PCM0_TX,
+	DMACH_PCM0_RX,
+	DMACH_PCM1_TX,
+	DMACH_PCM1_RX,
+	DMACH_PCM2_TX,
+	DMACH_PCM2_RX,
+	DMACH_MSM_REQ3,
+	DMACH_MSM_REQ2,
+	DMACH_MSM_REQ1,
+	DMACH_MSM_REQ0,
+	/* END Marker, also used to denote a reserved channel */
+	DMACH_MAX,
+};
+
+static inline bool s3c_dma_has_circular(void)
+{
+	return true;
+}
+
+#include <plat/dma.h>
+
+#endif	/* __S3C_DMA_PL330_H_ */
diff --git a/arch/arm/plat-samsung/include/plat/s3c-pl330-pdata.h b/arch/arm/plat-samsung/include/plat/s3c-pl330-pdata.h
new file mode 100644
index 000000000000..bf5e2a9d408d
--- /dev/null
+++ b/arch/arm/plat-samsung/include/plat/s3c-pl330-pdata.h
@@ -0,0 +1,32 @@
+/* linux/arch/arm/plat-samsung/include/plat/s3c-pl330-pdata.h
+ *
+ * Copyright (C) 2010 Samsung Electronics Co. Ltd.
+ *	Jaswinder Singh <jassi.brar@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __S3C_PL330_PDATA_H
+#define __S3C_PL330_PDATA_H
+
+#include <plat/s3c-dma-pl330.h>
+
+/*
+ * Every PL330 DMAC has max 32 peripheral interfaces,
+ * of which some may be not be really used in your
+ * DMAC's configuration.
+ * Populate this array of 32 peri i/fs with relevant
+ * channel IDs for used peri i/f and DMACH_MAX for
+ * those unused.
+ *
+ * The platforms just need to provide this info
+ * to the S3C DMA API driver for PL330.
+ */
+struct s3c_pl330_platdata {
+	enum dma_ch peri[32];
+};
+
+#endif /* __S3C_PL330_PDATA_H */
diff --git a/arch/arm/plat-samsung/s3c-pl330.c b/arch/arm/plat-samsung/s3c-pl330.c
new file mode 100644
index 000000000000..a91305a60aed
--- /dev/null
+++ b/arch/arm/plat-samsung/s3c-pl330.c
@@ -0,0 +1,1224 @@
+/* linux/arch/arm/plat-samsung/s3c-pl330.c
+ *
+ * Copyright (C) 2010 Samsung Electronics Co. Ltd.
+ *	Jaswinder Singh <jassi.brar@samsung.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+
+#include <asm/hardware/pl330.h>
+
+#include <plat/s3c-pl330-pdata.h>
+
+/**
+ * struct s3c_pl330_dmac - Logical representation of a PL330 DMAC.
+ * @busy_chan: Number of channels currently busy.
+ * @peri: List of IDs of peripherals this DMAC can work with.
+ * @node: To attach to the global list of DMACs.
+ * @pi: PL330 configuration info for the DMAC.
+ * @kmcache: Pool to quickly allocate xfers for all channels in the dmac.
+ */
+struct s3c_pl330_dmac {
+	unsigned		busy_chan;
+	enum dma_ch		*peri;
+	struct list_head	node;
+	struct pl330_info	*pi;
+	struct kmem_cache	*kmcache;
+};
+
+/**
+ * struct s3c_pl330_xfer - A request submitted by S3C DMA clients.
+ * @token: Xfer ID provided by the client.
+ * @node: To attach to the list of xfers on a channel.
+ * @px: Xfer for PL330 core.
+ * @chan: Owner channel of this xfer.
+ */
+struct s3c_pl330_xfer {
+	void			*token;
+	struct list_head	node;
+	struct pl330_xfer	px;
+	struct s3c_pl330_chan	*chan;
+};
+
+/**
+ * struct s3c_pl330_chan - Logical channel to communicate with
+ * 	a Physical peripheral.
+ * @pl330_chan_id: Token of a hardware channel thread of PL330 DMAC.
+ * 	NULL if the channel is available to be acquired.
+ * @id: ID of the peripheral that this channel can communicate with.
+ * @options: Options specified by the client.
+ * @sdaddr: Address provided via s3c2410_dma_devconfig.
+ * @node: To attach to the global list of channels.
+ * @lrq: Pointer to the last submitted pl330_req to PL330 core.
+ * @xfer_list: To manage list of xfers enqueued.
+ * @req: Two requests to communicate with the PL330 engine.
+ * @callback_fn: Callback function to the client.
+ * @rqcfg: Channel configuration for the xfers.
+ * @xfer_head: Pointer to the xfer to be next excecuted.
+ * @dmac: Pointer to the DMAC that manages this channel, NULL if the
+ * 	channel is available to be acquired.
+ * @client: Client of this channel. NULL if the
+ * 	channel is available to be acquired.
+ */
+struct s3c_pl330_chan {
+	void				*pl330_chan_id;
+	enum dma_ch			id;
+	unsigned int			options;
+	unsigned long			sdaddr;
+	struct list_head		node;
+	struct pl330_req		*lrq;
+	struct list_head		xfer_list;
+	struct pl330_req		req[2];
+	s3c2410_dma_cbfn_t		callback_fn;
+	struct pl330_reqcfg		rqcfg;
+	struct s3c_pl330_xfer		*xfer_head;
+	struct s3c_pl330_dmac		*dmac;
+	struct s3c2410_dma_client	*client;
+};
+
+/* All DMACs in the platform */
+static LIST_HEAD(dmac_list);
+
+/* All channels to peripherals in the platform */
+static LIST_HEAD(chan_list);
+
+/*
+ * Since we add resources(DMACs and Channels) to the global pool,
+ * we need to guard access to the resources using a global lock
+ */
+static DEFINE_SPINLOCK(res_lock);
+
+/* Returns the channel with ID 'id' in the chan_list */
+static struct s3c_pl330_chan *id_to_chan(const enum dma_ch id)
+{
+	struct s3c_pl330_chan *ch;
+
+	list_for_each_entry(ch, &chan_list, node)
+		if (ch->id == id)
+			return ch;
+
+	return NULL;
+}
+
+/* Allocate a new channel with ID 'id' and add to chan_list */
+static void chan_add(const enum dma_ch id)
+{
+	struct s3c_pl330_chan *ch = id_to_chan(id);
+
+	/* Return if the channel already exists */
+	if (ch)
+		return;
+
+	ch = kmalloc(sizeof(*ch), GFP_KERNEL);
+	/* Return silently to work with other channels */
+	if (!ch)
+		return;
+
+	ch->id = id;
+	ch->dmac = NULL;
+
+	list_add_tail(&ch->node, &chan_list);
+}
+
+/* If the channel is not yet acquired by any client */
+static bool chan_free(struct s3c_pl330_chan *ch)
+{
+	if (!ch)
+		return false;
+
+	/* Channel points to some DMAC only when it's acquired */
+	return ch->dmac ? false : true;
+}
+
+/*
+ * Returns 0 is peripheral i/f is invalid or not present on the dmac.
+ * Index + 1, otherwise.
+ */
+static unsigned iface_of_dmac(struct s3c_pl330_dmac *dmac, enum dma_ch ch_id)
+{
+	enum dma_ch *id = dmac->peri;
+	int i;
+
+	/* Discount invalid markers */
+	if (ch_id == DMACH_MAX)
+		return 0;
+
+	for (i = 0; i < PL330_MAX_PERI; i++)
+		if (id[i] == ch_id)
+			return i + 1;
+
+	return 0;
+}
+
+/* If all channel threads of the DMAC are busy */
+static inline bool dmac_busy(struct s3c_pl330_dmac *dmac)
+{
+	struct pl330_info *pi = dmac->pi;
+
+	return (dmac->busy_chan < pi->pcfg.num_chan) ? false : true;
+}
+
+/*
+ * Returns the number of free channels that
+ * can be handled by this dmac only.
+ */
+static unsigned ch_onlyby_dmac(struct s3c_pl330_dmac *dmac)
+{
+	enum dma_ch *id = dmac->peri;
+	struct s3c_pl330_dmac *d;
+	struct s3c_pl330_chan *ch;
+	unsigned found, count = 0;
+	enum dma_ch p;
+	int i;
+
+	for (i = 0; i < PL330_MAX_PERI; i++) {
+		p = id[i];
+		ch = id_to_chan(p);
+
+		if (p == DMACH_MAX || !chan_free(ch))
+			continue;
+
+		found = 0;
+		list_for_each_entry(d, &dmac_list, node) {
+			if (d != dmac && iface_of_dmac(d, ch->id)) {
+				found = 1;
+				break;
+			}
+		}
+		if (!found)
+			count++;
+	}
+
+	return count;
+}
+
+/*
+ * Measure of suitability of 'dmac' handling 'ch'
+ *
+ * 0 indicates 'dmac' can not handle 'ch' either
+ * because it is not supported by the hardware or
+ * because all dmac channels are currently busy.
+ *
+ * >0 vlaue indicates 'dmac' has the capability.
+ * The bigger the value the more suitable the dmac.
+ */
+#define MAX_SUIT	UINT_MAX
+#define MIN_SUIT	0
+
+static unsigned suitablility(struct s3c_pl330_dmac *dmac,
+		struct s3c_pl330_chan *ch)
+{
+	struct pl330_info *pi = dmac->pi;
+	enum dma_ch *id = dmac->peri;
+	struct s3c_pl330_dmac *d;
+	unsigned s;
+	int i;
+
+	s = MIN_SUIT;
+	/* If all the DMAC channel threads are busy */
+	if (dmac_busy(dmac))
+		return s;
+
+	for (i = 0; i < PL330_MAX_PERI; i++)
+		if (id[i] == ch->id)
+			break;
+
+	/* If the 'dmac' can't talk to 'ch' */
+	if (i == PL330_MAX_PERI)
+		return s;
+
+	s = MAX_SUIT;
+	list_for_each_entry(d, &dmac_list, node) {
+		/*
+		 * If some other dmac can talk to this
+		 * peri and has some channel free.
+		 */
+		if (d != dmac && iface_of_dmac(d, ch->id) && !dmac_busy(d)) {
+			s = 0;
+			break;
+		}
+	}
+	if (s)
+		return s;
+
+	s = 100;
+
+	/* Good if free chans are more, bad otherwise */
+	s += (pi->pcfg.num_chan - dmac->busy_chan) - ch_onlyby_dmac(dmac);
+
+	return s;
+}
+
+/* More than one DMAC may have capability to transfer data with the
+ * peripheral. This function assigns most suitable DMAC to manage the
+ * channel and hence communicate with the peripheral.
+ */
+static struct s3c_pl330_dmac *map_chan_to_dmac(struct s3c_pl330_chan *ch)
+{
+	struct s3c_pl330_dmac *d, *dmac = NULL;
+	unsigned sn, sl = MIN_SUIT;
+
+	list_for_each_entry(d, &dmac_list, node) {
+		sn = suitablility(d, ch);
+
+		if (sn == MAX_SUIT)
+			return d;
+
+		if (sn > sl)
+			dmac = d;
+	}
+
+	return dmac;
+}
+
+/* Acquire the channel for peripheral 'id' */
+static struct s3c_pl330_chan *chan_acquire(const enum dma_ch id)
+{
+	struct s3c_pl330_chan *ch = id_to_chan(id);
+	struct s3c_pl330_dmac *dmac;
+
+	/* If the channel doesn't exist or is already acquired */
+	if (!ch || !chan_free(ch)) {
+		ch = NULL;
+		goto acq_exit;
+	}
+
+	dmac = map_chan_to_dmac(ch);
+	/* If couldn't map */
+	if (!dmac) {
+		ch = NULL;
+		goto acq_exit;
+	}
+
+	dmac->busy_chan++;
+	ch->dmac = dmac;
+
+acq_exit:
+	return ch;
+}
+
+/* Delete xfer from the queue */
+static inline void del_from_queue(struct s3c_pl330_xfer *xfer)
+{
+	struct s3c_pl330_xfer *t;
+	struct s3c_pl330_chan *ch;
+	int found;
+
+	if (!xfer)
+		return;
+
+	ch = xfer->chan;
+
+	/* Make sure xfer is in the queue */
+	found = 0;
+	list_for_each_entry(t, &ch->xfer_list, node)
+		if (t == xfer) {
+			found = 1;
+			break;
+		}
+
+	if (!found)
+		return;
+
+	/* If xfer is last entry in the queue */
+	if (xfer->node.next == &ch->xfer_list)
+		t = list_entry(ch->xfer_list.next,
+				struct s3c_pl330_xfer, node);
+	else
+		t = list_entry(xfer->node.next,
+				struct s3c_pl330_xfer, node);
+
+	/* If there was only one node left */
+	if (t == xfer)
+		ch->xfer_head = NULL;
+	else if (ch->xfer_head == xfer)
+		ch->xfer_head = t;
+
+	list_del(&xfer->node);
+}
+
+/* Provides pointer to the next xfer in the queue.
+ * If CIRCULAR option is set, the list is left intact,
+ * otherwise the xfer is removed from the list.
+ * Forced delete 'pluck' can be set to override the CIRCULAR option.
+ */
+static struct s3c_pl330_xfer *get_from_queue(struct s3c_pl330_chan *ch,
+		int pluck)
+{
+	struct s3c_pl330_xfer *xfer = ch->xfer_head;
+
+	if (!xfer)
+		return NULL;
+
+	/* If xfer is last entry in the queue */
+	if (xfer->node.next == &ch->xfer_list)
+		ch->xfer_head = list_entry(ch->xfer_list.next,
+					struct s3c_pl330_xfer, node);
+	else
+		ch->xfer_head = list_entry(xfer->node.next,
+					struct s3c_pl330_xfer, node);
+
+	if (pluck || !(ch->options & S3C2410_DMAF_CIRCULAR))
+		del_from_queue(xfer);
+
+	return xfer;
+}
+
+static inline void add_to_queue(struct s3c_pl330_chan *ch,
+		struct s3c_pl330_xfer *xfer, int front)
+{
+	struct pl330_xfer *xt;
+
+	/* If queue empty */
+	if (ch->xfer_head == NULL)
+		ch->xfer_head = xfer;
+
+	xt = &ch->xfer_head->px;
+	/* If the head already submitted (CIRCULAR head) */
+	if (ch->options & S3C2410_DMAF_CIRCULAR &&
+		(xt == ch->req[0].x || xt == ch->req[1].x))
+		ch->xfer_head = xfer;
+
+	/* If this is a resubmission, it should go at the head */
+	if (front) {
+		ch->xfer_head = xfer;
+		list_add(&xfer->node, &ch->xfer_list);
+	} else {
+		list_add_tail(&xfer->node, &ch->xfer_list);
+	}
+}
+
+static inline void _finish_off(struct s3c_pl330_xfer *xfer,
+		enum s3c2410_dma_buffresult res, int ffree)
+{
+	struct s3c_pl330_chan *ch;
+
+	if (!xfer)
+		return;
+
+	ch = xfer->chan;
+
+	/* Do callback */
+	if (ch->callback_fn)
+		ch->callback_fn(NULL, xfer->token, xfer->px.bytes, res);
+
+	/* Force Free or if buffer is not needed anymore */
+	if (ffree || !(ch->options & S3C2410_DMAF_CIRCULAR))
+		kmem_cache_free(ch->dmac->kmcache, xfer);
+}
+
+static inline int s3c_pl330_submit(struct s3c_pl330_chan *ch,
+		struct pl330_req *r)
+{
+	struct s3c_pl330_xfer *xfer;
+	int ret = 0;
+
+	/* If already submitted */
+	if (r->x)
+		return 0;
+
+	xfer = get_from_queue(ch, 0);
+	if (xfer) {
+		r->x = &xfer->px;
+
+		/* Use max bandwidth for M<->M xfers */
+		if (r->rqtype == MEMTOMEM) {
+			struct pl330_info *pi = xfer->chan->dmac->pi;
+			int burst = 1 << ch->rqcfg.brst_size;
+			u32 bytes = r->x->bytes;
+			int bl;
+
+			bl = pi->pcfg.data_bus_width / 8;
+			bl *= pi->pcfg.data_buf_dep;
+			bl /= burst;
+
+			/* src/dst_burst_len can't be more than 16 */
+			if (bl > 16)
+				bl = 16;
+
+			while (bl > 1) {
+				if (!(bytes % (bl * burst)))
+					break;
+				bl--;
+			}
+
+			ch->rqcfg.brst_len = bl;
+		} else {
+			ch->rqcfg.brst_len = 1;
+		}
+
+		ret = pl330_submit_req(ch->pl330_chan_id, r);
+
+		/* If submission was successful */
+		if (!ret) {
+			ch->lrq = r; /* latest submitted req */
+			return 0;
+		}
+
+		r->x = NULL;
+
+		/* If both of the PL330 ping-pong buffers filled */
+		if (ret == -EAGAIN) {
+			dev_err(ch->dmac->pi->dev, "%s:%d!\n",
+				__func__, __LINE__);
+			/* Queue back again */
+			add_to_queue(ch, xfer, 1);
+			ret = 0;
+		} else {
+			dev_err(ch->dmac->pi->dev, "%s:%d!\n",
+				__func__, __LINE__);
+			_finish_off(xfer, S3C2410_RES_ERR, 0);
+		}
+	}
+
+	return ret;
+}
+
+static void s3c_pl330_rq(struct s3c_pl330_chan *ch,
+	struct pl330_req *r, enum pl330_op_err err)
+{
+	unsigned long flags;
+	struct s3c_pl330_xfer *xfer;
+	struct pl330_xfer *xl = r->x;
+	enum s3c2410_dma_buffresult res;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	r->x = NULL;
+
+	s3c_pl330_submit(ch, r);
+
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	/* Map result to S3C DMA API */
+	if (err == PL330_ERR_NONE)
+		res = S3C2410_RES_OK;
+	else if (err == PL330_ERR_ABORT)
+		res = S3C2410_RES_ABORT;
+	else
+		res = S3C2410_RES_ERR;
+
+	/* If last request had some xfer */
+	if (xl) {
+		xfer = container_of(xl, struct s3c_pl330_xfer, px);
+		_finish_off(xfer, res, 0);
+	} else {
+		dev_info(ch->dmac->pi->dev, "%s:%d No Xfer?!\n",
+			__func__, __LINE__);
+	}
+}
+
+static void s3c_pl330_rq0(void *token, enum pl330_op_err err)
+{
+	struct pl330_req *r = token;
+	struct s3c_pl330_chan *ch = container_of(r,
+					struct s3c_pl330_chan, req[0]);
+	s3c_pl330_rq(ch, r, err);
+}
+
+static void s3c_pl330_rq1(void *token, enum pl330_op_err err)
+{
+	struct pl330_req *r = token;
+	struct s3c_pl330_chan *ch = container_of(r,
+					struct s3c_pl330_chan, req[1]);
+	s3c_pl330_rq(ch, r, err);
+}
+
+/* Release an acquired channel */
+static void chan_release(struct s3c_pl330_chan *ch)
+{
+	struct s3c_pl330_dmac *dmac;
+
+	if (chan_free(ch))
+		return;
+
+	dmac = ch->dmac;
+	ch->dmac = NULL;
+	dmac->busy_chan--;
+}
+
+int s3c2410_dma_ctrl(enum dma_ch id, enum s3c2410_chan_op op)
+{
+	struct s3c_pl330_xfer *xfer;
+	enum pl330_chan_op pl330op;
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int idx, ret;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch)) {
+		ret = -EINVAL;
+		goto ctrl_exit;
+	}
+
+	switch (op) {
+	case S3C2410_DMAOP_START:
+		/* Make sure both reqs are enqueued */
+		idx = (ch->lrq == &ch->req[0]) ? 1 : 0;
+		s3c_pl330_submit(ch, &ch->req[idx]);
+		s3c_pl330_submit(ch, &ch->req[1 - idx]);
+		pl330op = PL330_OP_START;
+		break;
+
+	case S3C2410_DMAOP_STOP:
+		pl330op = PL330_OP_ABORT;
+		break;
+
+	case S3C2410_DMAOP_FLUSH:
+		pl330op = PL330_OP_FLUSH;
+		break;
+
+	case S3C2410_DMAOP_PAUSE:
+	case S3C2410_DMAOP_RESUME:
+	case S3C2410_DMAOP_TIMEOUT:
+	case S3C2410_DMAOP_STARTED:
+		spin_unlock_irqrestore(&res_lock, flags);
+		return 0;
+
+	default:
+		spin_unlock_irqrestore(&res_lock, flags);
+		return -EINVAL;
+	}
+
+	ret = pl330_chan_ctrl(ch->pl330_chan_id, pl330op);
+
+	if (pl330op == PL330_OP_START) {
+		spin_unlock_irqrestore(&res_lock, flags);
+		return ret;
+	}
+
+	idx = (ch->lrq == &ch->req[0]) ? 1 : 0;
+
+	/* Abort the current xfer */
+	if (ch->req[idx].x) {
+		xfer = container_of(ch->req[idx].x,
+				struct s3c_pl330_xfer, px);
+
+		/* Drop xfer during FLUSH */
+		if (pl330op == PL330_OP_FLUSH)
+			del_from_queue(xfer);
+
+		ch->req[idx].x = NULL;
+
+		spin_unlock_irqrestore(&res_lock, flags);
+		_finish_off(xfer, S3C2410_RES_ABORT,
+				pl330op == PL330_OP_FLUSH ? 1 : 0);
+		spin_lock_irqsave(&res_lock, flags);
+	}
+
+	/* Flush the whole queue */
+	if (pl330op == PL330_OP_FLUSH) {
+
+		if (ch->req[1 - idx].x) {
+			xfer = container_of(ch->req[1 - idx].x,
+					struct s3c_pl330_xfer, px);
+
+			del_from_queue(xfer);
+
+			ch->req[1 - idx].x = NULL;
+
+			spin_unlock_irqrestore(&res_lock, flags);
+			_finish_off(xfer, S3C2410_RES_ABORT, 1);
+			spin_lock_irqsave(&res_lock, flags);
+		}
+
+		/* Finish off the remaining in the queue */
+		xfer = ch->xfer_head;
+		while (xfer) {
+
+			del_from_queue(xfer);
+
+			spin_unlock_irqrestore(&res_lock, flags);
+			_finish_off(xfer, S3C2410_RES_ABORT, 1);
+			spin_lock_irqsave(&res_lock, flags);
+
+			xfer = ch->xfer_head;
+		}
+	}
+
+ctrl_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_ctrl);
+
+int s3c2410_dma_enqueue(enum dma_ch id, void *token,
+			dma_addr_t addr, int size)
+{
+	struct s3c_pl330_chan *ch;
+	struct s3c_pl330_xfer *xfer;
+	unsigned long flags;
+	int idx, ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	/* Error if invalid or free channel */
+	if (!ch || chan_free(ch)) {
+		ret = -EINVAL;
+		goto enq_exit;
+	}
+
+	/* Error if size is unaligned */
+	if (ch->rqcfg.brst_size && size % (1 << ch->rqcfg.brst_size)) {
+		ret = -EINVAL;
+		goto enq_exit;
+	}
+
+	xfer = kmem_cache_alloc(ch->dmac->kmcache, GFP_ATOMIC);
+	if (!xfer) {
+		ret = -ENOMEM;
+		goto enq_exit;
+	}
+
+	xfer->token = token;
+	xfer->chan = ch;
+	xfer->px.bytes = size;
+	xfer->px.next = NULL; /* Single request */
+
+	/* For S3C DMA API, direction is always fixed for all xfers */
+	if (ch->req[0].rqtype == MEMTODEV) {
+		xfer->px.src_addr = addr;
+		xfer->px.dst_addr = ch->sdaddr;
+	} else {
+		xfer->px.src_addr = ch->sdaddr;
+		xfer->px.dst_addr = addr;
+	}
+
+	add_to_queue(ch, xfer, 0);
+
+	/* Try submitting on either request */
+	idx = (ch->lrq == &ch->req[0]) ? 1 : 0;
+
+	if (!ch->req[idx].x)
+		s3c_pl330_submit(ch, &ch->req[idx]);
+	else
+		s3c_pl330_submit(ch, &ch->req[1 - idx]);
+
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	if (ch->options & S3C2410_DMAF_AUTOSTART)
+		s3c2410_dma_ctrl(id, S3C2410_DMAOP_START);
+
+	return 0;
+
+enq_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_enqueue);
+
+int s3c2410_dma_request(enum dma_ch id,
+			struct s3c2410_dma_client *client,
+			void *dev)
+{
+	struct s3c_pl330_dmac *dmac;
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = chan_acquire(id);
+	if (!ch) {
+		ret = -EBUSY;
+		goto req_exit;
+	}
+
+	dmac = ch->dmac;
+
+	ch->pl330_chan_id = pl330_request_channel(dmac->pi);
+	if (!ch->pl330_chan_id) {
+		chan_release(ch);
+		ret = -EBUSY;
+		goto req_exit;
+	}
+
+	ch->client = client;
+	ch->options = 0; /* Clear any option */
+	ch->callback_fn = NULL; /* Clear any callback */
+	ch->lrq = NULL;
+
+	ch->rqcfg.brst_size = 2; /* Default word size */
+	ch->rqcfg.swap = SWAP_NO;
+	ch->rqcfg.scctl = SCCTRL0; /* Noncacheable and nonbufferable */
+	ch->rqcfg.dcctl = DCCTRL0; /* Noncacheable and nonbufferable */
+	ch->rqcfg.privileged = 0;
+	ch->rqcfg.insnaccess = 0;
+
+	/* Set invalid direction */
+	ch->req[0].rqtype = DEVTODEV;
+	ch->req[1].rqtype = ch->req[0].rqtype;
+
+	ch->req[0].cfg = &ch->rqcfg;
+	ch->req[1].cfg = ch->req[0].cfg;
+
+	ch->req[0].peri = iface_of_dmac(dmac, id) - 1; /* Original index */
+	ch->req[1].peri = ch->req[0].peri;
+
+	ch->req[0].token = &ch->req[0];
+	ch->req[0].xfer_cb = s3c_pl330_rq0;
+	ch->req[1].token = &ch->req[1];
+	ch->req[1].xfer_cb = s3c_pl330_rq1;
+
+	ch->req[0].x = NULL;
+	ch->req[1].x = NULL;
+
+	/* Reset xfer list */
+	INIT_LIST_HEAD(&ch->xfer_list);
+	ch->xfer_head = NULL;
+
+req_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_request);
+
+int s3c2410_dma_free(enum dma_ch id, struct s3c2410_dma_client *client)
+{
+	struct s3c_pl330_chan *ch;
+	struct s3c_pl330_xfer *xfer;
+	unsigned long flags;
+	int ret = 0;
+	unsigned idx;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch))
+		goto free_exit;
+
+	/* Refuse if someone else wanted to free the channel */
+	if (ch->client != client) {
+		ret = -EBUSY;
+		goto free_exit;
+	}
+
+	/* Stop any active xfer, Flushe the queue and do callbacks */
+	pl330_chan_ctrl(ch->pl330_chan_id, PL330_OP_FLUSH);
+
+	/* Abort the submitted requests */
+	idx = (ch->lrq == &ch->req[0]) ? 1 : 0;
+
+	if (ch->req[idx].x) {
+		xfer = container_of(ch->req[idx].x,
+				struct s3c_pl330_xfer, px);
+
+		ch->req[idx].x = NULL;
+		del_from_queue(xfer);
+
+		spin_unlock_irqrestore(&res_lock, flags);
+		_finish_off(xfer, S3C2410_RES_ABORT, 1);
+		spin_lock_irqsave(&res_lock, flags);
+	}
+
+	if (ch->req[1 - idx].x) {
+		xfer = container_of(ch->req[1 - idx].x,
+				struct s3c_pl330_xfer, px);
+
+		ch->req[1 - idx].x = NULL;
+		del_from_queue(xfer);
+
+		spin_unlock_irqrestore(&res_lock, flags);
+		_finish_off(xfer, S3C2410_RES_ABORT, 1);
+		spin_lock_irqsave(&res_lock, flags);
+	}
+
+	/* Pluck and Abort the queued requests in order */
+	do {
+		xfer = get_from_queue(ch, 1);
+
+		spin_unlock_irqrestore(&res_lock, flags);
+		_finish_off(xfer, S3C2410_RES_ABORT, 1);
+		spin_lock_irqsave(&res_lock, flags);
+	} while (xfer);
+
+	ch->client = NULL;
+
+	pl330_release_channel(ch->pl330_chan_id);
+
+	ch->pl330_chan_id = NULL;
+
+	chan_release(ch);
+
+free_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_free);
+
+int s3c2410_dma_config(enum dma_ch id, int xferunit)
+{
+	struct s3c_pl330_chan *ch;
+	struct pl330_info *pi;
+	unsigned long flags;
+	int i, dbwidth, ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch)) {
+		ret = -EINVAL;
+		goto cfg_exit;
+	}
+
+	pi = ch->dmac->pi;
+	dbwidth = pi->pcfg.data_bus_width / 8;
+
+	/* Max size of xfer can be pcfg.data_bus_width */
+	if (xferunit > dbwidth) {
+		ret = -EINVAL;
+		goto cfg_exit;
+	}
+
+	i = 0;
+	while (xferunit != (1 << i))
+		i++;
+
+	/* If valid value */
+	if (xferunit == (1 << i))
+		ch->rqcfg.brst_size = i;
+	else
+		ret = -EINVAL;
+
+cfg_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_config);
+
+/* Options that are supported by this driver */
+#define S3C_PL330_FLAGS (S3C2410_DMAF_CIRCULAR | S3C2410_DMAF_AUTOSTART)
+
+int s3c2410_dma_setflags(enum dma_ch id, unsigned int options)
+{
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch) || options & ~(S3C_PL330_FLAGS))
+		ret = -EINVAL;
+	else
+		ch->options = options;
+
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_setflags);
+
+int s3c2410_dma_set_buffdone_fn(enum dma_ch id, s3c2410_dma_cbfn_t rtn)
+{
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch))
+		ret = -EINVAL;
+	else
+		ch->callback_fn = rtn;
+
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_set_buffdone_fn);
+
+int s3c2410_dma_devconfig(enum dma_ch id, enum s3c2410_dmasrc source,
+			  unsigned long address)
+{
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	ch = id_to_chan(id);
+
+	if (!ch || chan_free(ch)) {
+		ret = -EINVAL;
+		goto devcfg_exit;
+	}
+
+	switch (source) {
+	case S3C2410_DMASRC_HW: /* P->M */
+		ch->req[0].rqtype = DEVTOMEM;
+		ch->req[1].rqtype = DEVTOMEM;
+		ch->rqcfg.src_inc = 0;
+		ch->rqcfg.dst_inc = 1;
+		break;
+	case S3C2410_DMASRC_MEM: /* M->P */
+		ch->req[0].rqtype = MEMTODEV;
+		ch->req[1].rqtype = MEMTODEV;
+		ch->rqcfg.src_inc = 1;
+		ch->rqcfg.dst_inc = 0;
+		break;
+	default:
+		ret = -EINVAL;
+		goto devcfg_exit;
+	}
+
+	ch->sdaddr = address;
+
+devcfg_exit:
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return ret;
+}
+EXPORT_SYMBOL(s3c2410_dma_devconfig);
+
+int s3c2410_dma_getposition(enum dma_ch id, dma_addr_t *src, dma_addr_t *dst)
+{
+	struct s3c_pl330_chan *ch = id_to_chan(id);
+	struct pl330_chanstatus status;
+	int ret;
+
+	if (!ch || chan_free(ch))
+		return -EINVAL;
+
+	ret = pl330_chan_status(ch->pl330_chan_id, &status);
+	if (ret < 0)
+		return ret;
+
+	*src = status.src_addr;
+	*dst = status.dst_addr;
+
+	return 0;
+}
+EXPORT_SYMBOL(s3c2410_dma_getposition);
+
+static irqreturn_t pl330_irq_handler(int irq, void *data)
+{
+	if (pl330_update(data))
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
+}
+
+static int pl330_probe(struct platform_device *pdev)
+{
+	struct s3c_pl330_dmac *s3c_pl330_dmac;
+	struct s3c_pl330_platdata *pl330pd;
+	struct pl330_info *pl330_info;
+	struct resource *res;
+	int i, ret, irq;
+
+	pl330pd = pdev->dev.platform_data;
+
+	/* Can't do without the list of _32_ peripherals */
+	if (!pl330pd || !pl330pd->peri) {
+		dev_err(&pdev->dev, "platform data missing!\n");
+		return -ENODEV;
+	}
+
+	pl330_info = kzalloc(sizeof(*pl330_info), GFP_KERNEL);
+	if (!pl330_info)
+		return -ENOMEM;
+
+	pl330_info->pl330_data = NULL;
+	pl330_info->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		ret = -ENODEV;
+		goto probe_err1;
+	}
+
+	request_mem_region(res->start, resource_size(res), pdev->name);
+
+	pl330_info->base = ioremap(res->start, resource_size(res));
+	if (!pl330_info->base) {
+		ret = -ENXIO;
+		goto probe_err2;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		ret = irq;
+		goto probe_err3;
+	}
+
+	ret = request_irq(irq, pl330_irq_handler, 0,
+			dev_name(&pdev->dev), pl330_info);
+	if (ret)
+		goto probe_err4;
+
+	ret = pl330_add(pl330_info);
+	if (ret)
+		goto probe_err5;
+
+	/* Allocate a new DMAC */
+	s3c_pl330_dmac = kmalloc(sizeof(*s3c_pl330_dmac), GFP_KERNEL);
+	if (!s3c_pl330_dmac) {
+		ret = -ENOMEM;
+		goto probe_err6;
+	}
+
+	/* Hook the info */
+	s3c_pl330_dmac->pi = pl330_info;
+
+	/* No busy channels */
+	s3c_pl330_dmac->busy_chan = 0;
+
+	s3c_pl330_dmac->kmcache = kmem_cache_create(dev_name(&pdev->dev),
+				sizeof(struct s3c_pl330_xfer), 0, 0, NULL);
+
+	if (!s3c_pl330_dmac->kmcache) {
+		ret = -ENOMEM;
+		goto probe_err7;
+	}
+
+	/* Get the list of peripherals */
+	s3c_pl330_dmac->peri = pl330pd->peri;
+
+	/* Attach to the list of DMACs */
+	list_add_tail(&s3c_pl330_dmac->node, &dmac_list);
+
+	/* Create a channel for each peripheral in the DMAC
+	 * that is, if it doesn't already exist
+	 */
+	for (i = 0; i < PL330_MAX_PERI; i++)
+		if (s3c_pl330_dmac->peri[i] != DMACH_MAX)
+			chan_add(s3c_pl330_dmac->peri[i]);
+
+	printk(KERN_INFO
+		"Loaded driver for PL330 DMAC-%d %s\n",	pdev->id, pdev->name);
+	printk(KERN_INFO
+		"\tDBUFF-%ux%ubytes Num_Chans-%u Num_Peri-%u Num_Events-%u\n",
+		pl330_info->pcfg.data_buf_dep,
+		pl330_info->pcfg.data_bus_width / 8, pl330_info->pcfg.num_chan,
+		pl330_info->pcfg.num_peri, pl330_info->pcfg.num_events);
+
+	return 0;
+
+probe_err7:
+	kfree(s3c_pl330_dmac);
+probe_err6:
+	pl330_del(pl330_info);
+probe_err5:
+	free_irq(irq, pl330_info);
+probe_err4:
+probe_err3:
+	iounmap(pl330_info->base);
+probe_err2:
+	release_mem_region(res->start, resource_size(res));
+probe_err1:
+	kfree(pl330_info);
+
+	return ret;
+}
+
+static int pl330_remove(struct platform_device *pdev)
+{
+	struct s3c_pl330_dmac *dmac, *d;
+	struct s3c_pl330_chan *ch;
+	unsigned long flags;
+	int del, found;
+
+	if (!pdev->dev.platform_data)
+		return -EINVAL;
+
+	spin_lock_irqsave(&res_lock, flags);
+
+	found = 0;
+	list_for_each_entry(d, &dmac_list, node)
+		if (d->pi->dev == &pdev->dev) {
+			found = 1;
+			break;
+		}
+
+	if (!found) {
+		spin_unlock_irqrestore(&res_lock, flags);
+		return 0;
+	}
+
+	dmac = d;
+
+	/* Remove all Channels that are managed only by this DMAC */
+	list_for_each_entry(ch, &chan_list, node) {
+
+		/* Only channels that are handled by this DMAC */
+		if (iface_of_dmac(dmac, ch->id))
+			del = 1;
+		else
+			continue;
+
+		/* Don't remove if some other DMAC has it too */
+		list_for_each_entry(d, &dmac_list, node)
+			if (d != dmac && iface_of_dmac(d, ch->id)) {
+				del = 0;
+				break;
+			}
+
+		if (del) {
+			spin_unlock_irqrestore(&res_lock, flags);
+			s3c2410_dma_free(ch->id, ch->client);
+			spin_lock_irqsave(&res_lock, flags);
+			list_del(&ch->node);
+			kfree(ch);
+		}
+	}
+
+	/* Remove the DMAC */
+	list_del(&dmac->node);
+	kfree(dmac);
+
+	spin_unlock_irqrestore(&res_lock, flags);
+
+	return 0;
+}
+
+static struct platform_driver pl330_driver = {
+	.driver		= {
+		.owner	= THIS_MODULE,
+		.name	= "s3c-pl330",
+	},
+	.probe		= pl330_probe,
+	.remove		= pl330_remove,
+};
+
+static int __init pl330_init(void)
+{
+	return platform_driver_register(&pl330_driver);
+}
+module_init(pl330_init);
+
+static void __exit pl330_exit(void)
+{
+	platform_driver_unregister(&pl330_driver);
+	return;
+}
+module_exit(pl330_exit);
+
+MODULE_AUTHOR("Jaswinder Singh <jassi.brar@samsung.com>");
+MODULE_DESCRIPTION("Driver for PL330 DMA Controller");
+MODULE_LICENSE("GPL");