/* 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 <linux/clk.h>
#include <linux/err.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.
 * @clk: Pointer of DMAC operation clock.
 */
struct s3c_pl330_dmac {
        unsigned                busy_chan;
        enum dma_ch             *peri;
        struct list_head        node;
        struct pl330_info       *pi;
        struct kmem_cache       *kmcache;
        struct clk              *clk;
};

/**
 * 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;

        /* Allocate a new DMAC */
        s3c_pl330_dmac = kmalloc(sizeof(*s3c_pl330_dmac), GFP_KERNEL);
        if (!s3c_pl330_dmac) {
                ret = -ENOMEM;
                goto probe_err5;
        }

        /* Get operation clock and enable it */
        s3c_pl330_dmac->clk = clk_get(&pdev->dev, "pdma");
        if (IS_ERR(s3c_pl330_dmac->clk)) {
                dev_err(&pdev->dev, "Cannot get operation clock.\n");
                ret = -EINVAL;
                goto probe_err6;
        }
        clk_enable(s3c_pl330_dmac->clk);

        ret = pl330_add(pl330_info);
        if (ret)
                goto probe_err7;

        /* 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_err8;
        }

        /* 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_err8:
        pl330_del(pl330_info);
probe_err7:
        clk_disable(s3c_pl330_dmac->clk);
        clk_put(s3c_pl330_dmac->clk);
probe_err6:
        kfree(s3c_pl330_dmac);
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);
                }
        }

        /* Disable operation clock */
        clk_disable(dmac->clk);
        clk_put(dmac->clk);

        /* 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");