/*
 * Renesas USB driver
 *
 * Copyright (C) 2011 Renesas Solutions Corp.
 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
#include <linux/delay.h>
#include <linux/io.h>
#include <linux/scatterlist.h>
#include "common.h"
#include "pipe.h"

#define usbhsf_get_cfifo(p)     (&((p)->fifo_info.cfifo))
#define usbhsf_is_cfifo(p, f)   (usbhsf_get_cfifo(p) == f)

#define usbhsf_fifo_is_busy(f)  ((f)->pipe) /* see usbhs_pipe_select_fifo */

/*
 *              packet initialize
 */
void usbhs_pkt_init(struct usbhs_pkt *pkt)
{
        INIT_LIST_HEAD(&pkt->node);
}

/*
 *              packet control function
 */
static int usbhsf_null_handle(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);
        struct device *dev = usbhs_priv_to_dev(priv);

        dev_err(dev, "null handler\n");

        return -EINVAL;
}

static const struct usbhs_pkt_handle usbhsf_null_handler = {
        .prepare = usbhsf_null_handle,
        .try_run = usbhsf_null_handle,
};

void usbhs_pkt_push(struct usbhs_pipe *pipe, struct usbhs_pkt *pkt,
                    void (*done)(struct usbhs_priv *priv,
                                 struct usbhs_pkt *pkt),
                    void *buf, int len, int zero, int sequence)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct device *dev = usbhs_priv_to_dev(priv);
        unsigned long flags;

        if (!done) {
                dev_err(dev, "no done function\n");
                return;
        }

        /********************  spin lock ********************/
        usbhs_lock(priv, flags);

        if (!pipe->handler) {
                dev_err(dev, "no handler function\n");
                pipe->handler = &usbhsf_null_handler;
        }

        list_move_tail(&pkt->node, &pipe->list);

        /*
         * each pkt must hold own handler.
         * because handler might be changed by its situation.
         * dma handler -> pio handler.
         */
        pkt->pipe       = pipe;
        pkt->buf        = buf;
        pkt->handler    = pipe->handler;
        pkt->length     = len;
        pkt->zero       = zero;
        pkt->actual     = 0;
        pkt->done       = done;
        pkt->sequence   = sequence;

        usbhs_unlock(priv, flags);
        /********************  spin unlock ******************/
}

static void __usbhsf_pkt_del(struct usbhs_pkt *pkt)
{
        list_del_init(&pkt->node);
}

static struct usbhs_pkt *__usbhsf_pkt_get(struct usbhs_pipe *pipe)
{
        return list_first_entry_or_null(&pipe->list, struct usbhs_pkt, node);
}

static void usbhsf_fifo_clear(struct usbhs_pipe *pipe,
                              struct usbhs_fifo *fifo);
static void usbhsf_fifo_unselect(struct usbhs_pipe *pipe,
                                 struct usbhs_fifo *fifo);
static struct dma_chan *usbhsf_dma_chan_get(struct usbhs_fifo *fifo,
                                            struct usbhs_pkt *pkt);
#define usbhsf_dma_map(p)       __usbhsf_dma_map_ctrl(p, 1)
#define usbhsf_dma_unmap(p)     __usbhsf_dma_map_ctrl(p, 0)
static int __usbhsf_dma_map_ctrl(struct usbhs_pkt *pkt, int map);
struct usbhs_pkt *usbhs_pkt_pop(struct usbhs_pipe *pipe, struct usbhs_pkt *pkt)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhs_pipe_to_fifo(pipe);
        unsigned long flags;

        /********************  spin lock ********************/
        usbhs_lock(priv, flags);

        usbhs_pipe_disable(pipe);

        if (!pkt)
                pkt = __usbhsf_pkt_get(pipe);

        if (pkt) {
                struct dma_chan *chan = NULL;

                if (fifo)
                        chan = usbhsf_dma_chan_get(fifo, pkt);
                if (chan) {
                        dmaengine_terminate_all(chan);
                        usbhsf_fifo_clear(pipe, fifo);
                        usbhsf_dma_unmap(pkt);
                }

                __usbhsf_pkt_del(pkt);
        }

        if (fifo)
                usbhsf_fifo_unselect(pipe, fifo);

        usbhs_unlock(priv, flags);
        /********************  spin unlock ******************/

        return pkt;
}

enum {
        USBHSF_PKT_PREPARE,
        USBHSF_PKT_TRY_RUN,
        USBHSF_PKT_DMA_DONE,
};

static int usbhsf_pkt_handler(struct usbhs_pipe *pipe, int type)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_pkt *pkt;
        struct device *dev = usbhs_priv_to_dev(priv);
        int (*func)(struct usbhs_pkt *pkt, int *is_done);
        unsigned long flags;
        int ret = 0;
        int is_done = 0;

        /********************  spin lock ********************/
        usbhs_lock(priv, flags);

        pkt = __usbhsf_pkt_get(pipe);
        if (!pkt)
                goto __usbhs_pkt_handler_end;

        switch (type) {
        case USBHSF_PKT_PREPARE:
                func = pkt->handler->prepare;
                break;
        case USBHSF_PKT_TRY_RUN:
                func = pkt->handler->try_run;
                break;
        case USBHSF_PKT_DMA_DONE:
                func = pkt->handler->dma_done;
                break;
        default:
                dev_err(dev, "unknown pkt handler\n");
                goto __usbhs_pkt_handler_end;
        }

        if (likely(func))
                ret = func(pkt, &is_done);

        if (is_done)
                __usbhsf_pkt_del(pkt);

__usbhs_pkt_handler_end:
        usbhs_unlock(priv, flags);
        /********************  spin unlock ******************/

        if (is_done) {
                pkt->done(priv, pkt);
                usbhs_pkt_start(pipe);
        }

        return ret;
}

void usbhs_pkt_start(struct usbhs_pipe *pipe)
{
        usbhsf_pkt_handler(pipe, USBHSF_PKT_PREPARE);
}

/*
 *              irq enable/disable function
 */
#define usbhsf_irq_empty_ctrl(p, e) usbhsf_irq_callback_ctrl(p, irq_bempsts, e)
#define usbhsf_irq_ready_ctrl(p, e) usbhsf_irq_callback_ctrl(p, irq_brdysts, e)
#define usbhsf_irq_callback_ctrl(pipe, status, enable)                  \
        ({                                                              \
                struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);     \
                struct usbhs_mod *mod = usbhs_mod_get_current(priv);    \
                u16 status = (1 << usbhs_pipe_number(pipe));            \
                if (!mod)                                               \
                        return;                                         \
                if (enable)                                             \
                        mod->status |= status;                          \
                else                                                    \
                        mod->status &= ~status;                         \
                usbhs_irq_callback_update(priv, mod);                   \
        })

static void usbhsf_tx_irq_ctrl(struct usbhs_pipe *pipe, int enable)
{
        /*
         * And DCP pipe can NOT use "ready interrupt" for "send"
         * it should use "empty" interrupt.
         * see
         *   "Operation" - "Interrupt Function" - "BRDY Interrupt"
         *
         * on the other hand, normal pipe can use "ready interrupt" for "send"
         * even though it is single/double buffer
         */
        if (usbhs_pipe_is_dcp(pipe))
                usbhsf_irq_empty_ctrl(pipe, enable);
        else
                usbhsf_irq_ready_ctrl(pipe, enable);
}

static void usbhsf_rx_irq_ctrl(struct usbhs_pipe *pipe, int enable)
{
        usbhsf_irq_ready_ctrl(pipe, enable);
}

/*
 *              FIFO ctrl
 */
static void usbhsf_send_terminator(struct usbhs_pipe *pipe,
                                   struct usbhs_fifo *fifo)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);

        usbhs_bset(priv, fifo->ctr, BVAL, BVAL);
}

static int usbhsf_fifo_barrier(struct usbhs_priv *priv,
                               struct usbhs_fifo *fifo)
{
        int timeout = 1024;

        do {
                /* The FIFO port is accessible */
                if (usbhs_read(priv, fifo->ctr) & FRDY)
                        return 0;

                udelay(10);
        } while (timeout--);

        return -EBUSY;
}

static void usbhsf_fifo_clear(struct usbhs_pipe *pipe,
                              struct usbhs_fifo *fifo)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);

        if (!usbhs_pipe_is_dcp(pipe))
                usbhsf_fifo_barrier(priv, fifo);

        usbhs_write(priv, fifo->ctr, BCLR);
}

static int usbhsf_fifo_rcv_len(struct usbhs_priv *priv,
                               struct usbhs_fifo *fifo)
{
        return usbhs_read(priv, fifo->ctr) & DTLN_MASK;
}

static void usbhsf_fifo_unselect(struct usbhs_pipe *pipe,
                                 struct usbhs_fifo *fifo)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);

        usbhs_pipe_select_fifo(pipe, NULL);
        usbhs_write(priv, fifo->sel, 0);
}

static int usbhsf_fifo_select(struct usbhs_pipe *pipe,
                              struct usbhs_fifo *fifo,
                              int write)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct device *dev = usbhs_priv_to_dev(priv);
        int timeout = 1024;
        u16 mask = ((1 << 5) | 0xF);            /* mask of ISEL | CURPIPE */
        u16 base = usbhs_pipe_number(pipe);     /* CURPIPE */

        if (usbhs_pipe_is_busy(pipe) ||
            usbhsf_fifo_is_busy(fifo))
                return -EBUSY;

        if (usbhs_pipe_is_dcp(pipe)) {
                base |= (1 == write) << 5;      /* ISEL */

                if (usbhs_mod_is_host(priv))
                        usbhs_dcp_dir_for_host(pipe, write);
        }

        /* "base" will be used below  */
        if (usbhs_get_dparam(priv, has_sudmac) && !usbhsf_is_cfifo(priv, fifo))
                usbhs_write(priv, fifo->sel, base);
        else
                usbhs_write(priv, fifo->sel, base | MBW_32);

        /* check ISEL and CURPIPE value */
        while (timeout--) {
                if (base == (mask & usbhs_read(priv, fifo->sel))) {
                        usbhs_pipe_select_fifo(pipe, fifo);
                        return 0;
                }
                udelay(10);
        }

        dev_err(dev, "fifo select error\n");

        return -EIO;
}

/*
 *              DCP status stage
 */
static int usbhs_dcp_dir_switch_to_write(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv); /* CFIFO */
        struct device *dev = usbhs_priv_to_dev(priv);
        int ret;

        usbhs_pipe_disable(pipe);

        ret = usbhsf_fifo_select(pipe, fifo, 1);
        if (ret < 0) {
                dev_err(dev, "%s() faile\n", __func__);
                return ret;
        }

        usbhs_pipe_sequence_data1(pipe); /* DATA1 */

        usbhsf_fifo_clear(pipe, fifo);
        usbhsf_send_terminator(pipe, fifo);

        usbhsf_fifo_unselect(pipe, fifo);

        usbhsf_tx_irq_ctrl(pipe, 1);
        usbhs_pipe_enable(pipe);

        return ret;
}

static int usbhs_dcp_dir_switch_to_read(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv); /* CFIFO */
        struct device *dev = usbhs_priv_to_dev(priv);
        int ret;

        usbhs_pipe_disable(pipe);

        ret = usbhsf_fifo_select(pipe, fifo, 0);
        if (ret < 0) {
                dev_err(dev, "%s() fail\n", __func__);
                return ret;
        }

        usbhs_pipe_sequence_data1(pipe); /* DATA1 */
        usbhsf_fifo_clear(pipe, fifo);

        usbhsf_fifo_unselect(pipe, fifo);

        usbhsf_rx_irq_ctrl(pipe, 1);
        usbhs_pipe_enable(pipe);

        return ret;

}

static int usbhs_dcp_dir_switch_done(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;

        if (pkt->handler == &usbhs_dcp_status_stage_in_handler)
                usbhsf_tx_irq_ctrl(pipe, 0);
        else
                usbhsf_rx_irq_ctrl(pipe, 0);

        pkt->actual = pkt->length;
        *is_done = 1;

        return 0;
}

const struct usbhs_pkt_handle usbhs_dcp_status_stage_in_handler = {
        .prepare = usbhs_dcp_dir_switch_to_write,
        .try_run = usbhs_dcp_dir_switch_done,
};

const struct usbhs_pkt_handle usbhs_dcp_status_stage_out_handler = {
        .prepare = usbhs_dcp_dir_switch_to_read,
        .try_run = usbhs_dcp_dir_switch_done,
};

/*
 *              DCP data stage (push)
 */
static int usbhsf_dcp_data_stage_try_push(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;

        usbhs_pipe_sequence_data1(pipe); /* DATA1 */

        /*
         * change handler to PIO push
         */
        pkt->handler = &usbhs_fifo_pio_push_handler;

        return pkt->handler->prepare(pkt, is_done);
}

const struct usbhs_pkt_handle usbhs_dcp_data_stage_out_handler = {
        .prepare = usbhsf_dcp_data_stage_try_push,
};

/*
 *              DCP data stage (pop)
 */
static int usbhsf_dcp_data_stage_prepare_pop(struct usbhs_pkt *pkt,
                                             int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv);

        if (usbhs_pipe_is_busy(pipe))
                return 0;

        /*
         * prepare pop for DCP should
         *  - change DCP direction,
         *  - clear fifo
         *  - DATA1
         */
        usbhs_pipe_disable(pipe);

        usbhs_pipe_sequence_data1(pipe); /* DATA1 */

        usbhsf_fifo_select(pipe, fifo, 0);
        usbhsf_fifo_clear(pipe, fifo);
        usbhsf_fifo_unselect(pipe, fifo);

        /*
         * change handler to PIO pop
         */
        pkt->handler = &usbhs_fifo_pio_pop_handler;

        return pkt->handler->prepare(pkt, is_done);
}

const struct usbhs_pkt_handle usbhs_dcp_data_stage_in_handler = {
        .prepare = usbhsf_dcp_data_stage_prepare_pop,
};

/*
 *              PIO push handler
 */
static int usbhsf_pio_try_push(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct device *dev = usbhs_priv_to_dev(priv);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv); /* CFIFO */
        void __iomem *addr = priv->base + fifo->port;
        u8 *buf;
        int maxp = usbhs_pipe_get_maxpacket(pipe);
        int total_len;
        int i, ret, len;
        int is_short;

        usbhs_pipe_data_sequence(pipe, pkt->sequence);
        pkt->sequence = -1; /* -1 sequence will be ignored */

        usbhs_pipe_set_trans_count_if_bulk(pipe, pkt->length);

        ret = usbhsf_fifo_select(pipe, fifo, 1);
        if (ret < 0)
                return 0;

        ret = usbhs_pipe_is_accessible(pipe);
        if (ret < 0) {
                /* inaccessible pipe is not an error */
                ret = 0;
                goto usbhs_fifo_write_busy;
        }

        ret = usbhsf_fifo_barrier(priv, fifo);
        if (ret < 0)
                goto usbhs_fifo_write_busy;

        buf             = pkt->buf    + pkt->actual;
        len             = pkt->length - pkt->actual;
        len             = min(len, maxp);
        total_len       = len;
        is_short        = total_len < maxp;

        /*
         * FIXME
         *
         * 32-bit access only
         */
        if (len >= 4 && !((unsigned long)buf & 0x03)) {
                iowrite32_rep(addr, buf, len / 4);
                len %= 4;
                buf += total_len - len;
        }

        /* the rest operation */
        for (i = 0; i < len; i++)
                iowrite8(buf[i], addr + (0x03 - (i & 0x03)));

        /*
         * variable update
         */
        pkt->actual += total_len;

        if (pkt->actual < pkt->length)
                *is_done = 0;           /* there are remainder data */
        else if (is_short)
                *is_done = 1;           /* short packet */
        else
                *is_done = !pkt->zero;  /* send zero packet ? */

        /*
         * pipe/irq handling
         */
        if (is_short)
                usbhsf_send_terminator(pipe, fifo);

        usbhsf_tx_irq_ctrl(pipe, !*is_done);
        usbhs_pipe_running(pipe, !*is_done);
        usbhs_pipe_enable(pipe);

        dev_dbg(dev, "  send %d (%d/ %d/ %d/ %d)\n",
                usbhs_pipe_number(pipe),
                pkt->length, pkt->actual, *is_done, pkt->zero);

        usbhsf_fifo_unselect(pipe, fifo);

        return 0;

usbhs_fifo_write_busy:
        usbhsf_fifo_unselect(pipe, fifo);

        /*
         * pipe is busy.
         * retry in interrupt
         */
        usbhsf_tx_irq_ctrl(pipe, 1);
        usbhs_pipe_running(pipe, 1);

        return ret;
}

static int usbhsf_pio_prepare_push(struct usbhs_pkt *pkt, int *is_done)
{
        if (usbhs_pipe_is_running(pkt->pipe))
                return 0;

        return usbhsf_pio_try_push(pkt, is_done);
}

const struct usbhs_pkt_handle usbhs_fifo_pio_push_handler = {
        .prepare = usbhsf_pio_prepare_push,
        .try_run = usbhsf_pio_try_push,
};

/*
 *              PIO pop handler
 */
static int usbhsf_prepare_pop(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv);

        if (usbhs_pipe_is_busy(pipe))
                return 0;

        if (usbhs_pipe_is_running(pipe))
                return 0;

        /*
         * pipe enable to prepare packet receive
         */
        usbhs_pipe_data_sequence(pipe, pkt->sequence);
        pkt->sequence = -1; /* -1 sequence will be ignored */

        if (usbhs_pipe_is_dcp(pipe))
                usbhsf_fifo_clear(pipe, fifo);

        usbhs_pipe_set_trans_count_if_bulk(pipe, pkt->length);
        usbhs_pipe_enable(pipe);
        usbhs_pipe_running(pipe, 1);
        usbhsf_rx_irq_ctrl(pipe, 1);

        return 0;
}

static int usbhsf_pio_try_pop(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct device *dev = usbhs_priv_to_dev(priv);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv); /* CFIFO */
        void __iomem *addr = priv->base + fifo->port;
        u8 *buf;
        u32 data = 0;
        int maxp = usbhs_pipe_get_maxpacket(pipe);
        int rcv_len, len;
        int i, ret;
        int total_len = 0;

        ret = usbhsf_fifo_select(pipe, fifo, 0);
        if (ret < 0)
                return 0;

        ret = usbhsf_fifo_barrier(priv, fifo);
        if (ret < 0)
                goto usbhs_fifo_read_busy;

        rcv_len = usbhsf_fifo_rcv_len(priv, fifo);

        buf             = pkt->buf    + pkt->actual;
        len             = pkt->length - pkt->actual;
        len             = min(len, rcv_len);
        total_len       = len;

        /*
         * update actual length first here to decide disable pipe.
         * if this pipe keeps BUF status and all data were popped,
         * then, next interrupt/token will be issued again
         */
        pkt->actual += total_len;

        if ((pkt->actual == pkt->length) ||     /* receive all data */
            (total_len < maxp)) {               /* short packet */
                *is_done = 1;
                usbhsf_rx_irq_ctrl(pipe, 0);
                usbhs_pipe_running(pipe, 0);
                /*
                 * If function mode, since this controller is possible to enter
                 * Control Write status stage at this timing, this driver
                 * should not disable the pipe. If such a case happens, this
                 * controller is not able to complete the status stage.
                 */
                if (!usbhs_mod_is_host(priv) && !usbhs_pipe_is_dcp(pipe))
                        usbhs_pipe_disable(pipe);       /* disable pipe first */
        }

        /*
         * Buffer clear if Zero-Length packet
         *
         * see
         * "Operation" - "FIFO Buffer Memory" - "FIFO Port Function"
         */
        if (0 == rcv_len) {
                pkt->zero = 1;
                usbhsf_fifo_clear(pipe, fifo);
                goto usbhs_fifo_read_end;
        }

        /*
         * FIXME
         *
         * 32-bit access only
         */
        if (len >= 4 && !((unsigned long)buf & 0x03)) {
                ioread32_rep(addr, buf, len / 4);
                len %= 4;
                buf += total_len - len;
        }

        /* the rest operation */
        for (i = 0; i < len; i++) {
                if (!(i & 0x03))
                        data = ioread32(addr);

                buf[i] = (data >> ((i & 0x03) * 8)) & 0xff;
        }

usbhs_fifo_read_end:
        dev_dbg(dev, "  recv %d (%d/ %d/ %d/ %d)\n",
                usbhs_pipe_number(pipe),
                pkt->length, pkt->actual, *is_done, pkt->zero);

usbhs_fifo_read_busy:
        usbhsf_fifo_unselect(pipe, fifo);

        return ret;
}

const struct usbhs_pkt_handle usbhs_fifo_pio_pop_handler = {
        .prepare = usbhsf_prepare_pop,
        .try_run = usbhsf_pio_try_pop,
};

/*
 *              DCP ctrol statge handler
 */
static int usbhsf_ctrl_stage_end(struct usbhs_pkt *pkt, int *is_done)
{
        usbhs_dcp_control_transfer_done(pkt->pipe);

        *is_done = 1;

        return 0;
}

const struct usbhs_pkt_handle usbhs_ctrl_stage_end_handler = {
        .prepare = usbhsf_ctrl_stage_end,
        .try_run = usbhsf_ctrl_stage_end,
};

/*
 *              DMA fifo functions
 */
static struct dma_chan *usbhsf_dma_chan_get(struct usbhs_fifo *fifo,
                                            struct usbhs_pkt *pkt)
{
        if (&usbhs_fifo_dma_push_handler == pkt->handler)
                return fifo->tx_chan;

        if (&usbhs_fifo_dma_pop_handler == pkt->handler)
                return fifo->rx_chan;

        return NULL;
}

static struct usbhs_fifo *usbhsf_get_dma_fifo(struct usbhs_priv *priv,
                                              struct usbhs_pkt *pkt)
{
        struct usbhs_fifo *fifo;
        int i;

        usbhs_for_each_dfifo(priv, fifo, i) {
                if (usbhsf_dma_chan_get(fifo, pkt) &&
                    !usbhsf_fifo_is_busy(fifo))
                        return fifo;
        }

        return NULL;
}

#define usbhsf_dma_start(p, f)  __usbhsf_dma_ctrl(p, f, DREQE)
#define usbhsf_dma_stop(p, f)   __usbhsf_dma_ctrl(p, f, 0)
static void __usbhsf_dma_ctrl(struct usbhs_pipe *pipe,
                              struct usbhs_fifo *fifo,
                              u16 dreqe)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);

        usbhs_bset(priv, fifo->sel, DREQE, dreqe);
}

static int __usbhsf_dma_map_ctrl(struct usbhs_pkt *pkt, int map)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_pipe_info *info = usbhs_priv_to_pipeinfo(priv);
        struct usbhs_fifo *fifo = usbhs_pipe_to_fifo(pipe);
        struct dma_chan *chan = usbhsf_dma_chan_get(fifo, pkt);

        return info->dma_map_ctrl(chan->device->dev, pkt, map);
}

static void usbhsf_dma_complete(void *arg);
static void xfer_work(struct work_struct *work)
{
        struct usbhs_pkt *pkt = container_of(work, struct usbhs_pkt, work);
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_fifo *fifo;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct dma_async_tx_descriptor *desc;
        struct dma_chan *chan;
        struct device *dev = usbhs_priv_to_dev(priv);
        enum dma_transfer_direction dir;
        unsigned long flags;

        usbhs_lock(priv, flags);
        fifo = usbhs_pipe_to_fifo(pipe);
        if (!fifo)
                goto xfer_work_end;

        chan = usbhsf_dma_chan_get(fifo, pkt);
        dir = usbhs_pipe_is_dir_in(pipe) ? DMA_DEV_TO_MEM : DMA_MEM_TO_DEV;

        desc = dmaengine_prep_slave_single(chan, pkt->dma + pkt->actual,
                                        pkt->trans, dir,
                                        DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc)
                goto xfer_work_end;

        desc->callback          = usbhsf_dma_complete;
        desc->callback_param    = pipe;

        pkt->cookie = dmaengine_submit(desc);
        if (pkt->cookie < 0) {
                dev_err(dev, "Failed to submit dma descriptor\n");
                goto xfer_work_end;
        }

        dev_dbg(dev, "  %s %d (%d/ %d)\n",
                fifo->name, usbhs_pipe_number(pipe), pkt->length, pkt->zero);

        usbhs_pipe_running(pipe, 1);
        usbhsf_dma_start(pipe, fifo);
        usbhs_pipe_set_trans_count_if_bulk(pipe, pkt->trans);
        dma_async_issue_pending(chan);
        usbhs_pipe_enable(pipe);

xfer_work_end:
        usbhs_unlock(priv, flags);
}

/*
 *              DMA push handler
 */
static int usbhsf_dma_prepare_push(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo;
        int len = pkt->length - pkt->actual;
        int ret;
        uintptr_t align_mask;

        if (usbhs_pipe_is_busy(pipe))
                return 0;

        /* use PIO if packet is less than pio_dma_border or pipe is DCP */
        if ((len < usbhs_get_dparam(priv, pio_dma_border)) ||
            usbhs_pipe_type_is(pipe, USB_ENDPOINT_XFER_ISOC))
                goto usbhsf_pio_prepare_push;

        /* check data length if this driver don't use USB-DMAC */
        if (!usbhs_get_dparam(priv, has_usb_dmac) && len & 0x7)
                goto usbhsf_pio_prepare_push;

        /* check buffer alignment */
        align_mask = usbhs_get_dparam(priv, has_usb_dmac) ?
                                        USBHS_USB_DMAC_XFER_SIZE - 1 : 0x7;
        if ((uintptr_t)(pkt->buf + pkt->actual) & align_mask)
                goto usbhsf_pio_prepare_push;

        /* return at this time if the pipe is running */
        if (usbhs_pipe_is_running(pipe))
                return 0;

        /* get enable DMA fifo */
        fifo = usbhsf_get_dma_fifo(priv, pkt);
        if (!fifo)
                goto usbhsf_pio_prepare_push;

        ret = usbhsf_fifo_select(pipe, fifo, 0);
        if (ret < 0)
                goto usbhsf_pio_prepare_push;

        if (usbhsf_dma_map(pkt) < 0)
                goto usbhsf_pio_prepare_push_unselect;

        pkt->trans = len;

        usbhsf_tx_irq_ctrl(pipe, 0);
        INIT_WORK(&pkt->work, xfer_work);
        schedule_work(&pkt->work);

        return 0;

usbhsf_pio_prepare_push_unselect:
        usbhsf_fifo_unselect(pipe, fifo);
usbhsf_pio_prepare_push:
        /*
         * change handler to PIO
         */
        pkt->handler = &usbhs_fifo_pio_push_handler;

        return pkt->handler->prepare(pkt, is_done);
}

static int usbhsf_dma_push_done(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        int is_short = pkt->trans % usbhs_pipe_get_maxpacket(pipe);

        pkt->actual += pkt->trans;

        if (pkt->actual < pkt->length)
                *is_done = 0;           /* there are remainder data */
        else if (is_short)
                *is_done = 1;           /* short packet */
        else
                *is_done = !pkt->zero;  /* send zero packet? */

        usbhs_pipe_running(pipe, !*is_done);

        usbhsf_dma_stop(pipe, pipe->fifo);
        usbhsf_dma_unmap(pkt);
        usbhsf_fifo_unselect(pipe, pipe->fifo);

        if (!*is_done) {
                /* change handler to PIO */
                pkt->handler = &usbhs_fifo_pio_push_handler;
                return pkt->handler->try_run(pkt, is_done);
        }

        return 0;
}

const struct usbhs_pkt_handle usbhs_fifo_dma_push_handler = {
        .prepare        = usbhsf_dma_prepare_push,
        .dma_done       = usbhsf_dma_push_done,
};

/*
 *              DMA pop handler
 */

static int usbhsf_dma_prepare_pop_with_rx_irq(struct usbhs_pkt *pkt,
                                              int *is_done)
{
        return usbhsf_prepare_pop(pkt, is_done);
}

static int usbhsf_dma_prepare_pop_with_usb_dmac(struct usbhs_pkt *pkt,
                                                int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo;
        int ret;

        if (usbhs_pipe_is_busy(pipe))
                return 0;

        /* use PIO if packet is less than pio_dma_border or pipe is DCP */
        if ((pkt->length < usbhs_get_dparam(priv, pio_dma_border)) ||
            usbhs_pipe_type_is(pipe, USB_ENDPOINT_XFER_ISOC))
                goto usbhsf_pio_prepare_pop;

        fifo = usbhsf_get_dma_fifo(priv, pkt);
        if (!fifo)
                goto usbhsf_pio_prepare_pop;

        if ((uintptr_t)pkt->buf & (USBHS_USB_DMAC_XFER_SIZE - 1))
                goto usbhsf_pio_prepare_pop;

        usbhs_pipe_config_change_bfre(pipe, 1);

        ret = usbhsf_fifo_select(pipe, fifo, 0);
        if (ret < 0)
                goto usbhsf_pio_prepare_pop;

        if (usbhsf_dma_map(pkt) < 0)
                goto usbhsf_pio_prepare_pop_unselect;

        /* DMA */

        /*
         * usbhs_fifo_dma_pop_handler :: prepare
         * enabled irq to come here.
         * but it is no longer needed for DMA. disable it.

         */
        usbhsf_rx_irq_ctrl(pipe, 0);

        pkt->trans = pkt->length;

        INIT_WORK(&pkt->work, xfer_work);
        schedule_work(&pkt->work);

        return 0;

usbhsf_pio_prepare_pop_unselect:
        usbhsf_fifo_unselect(pipe, fifo);
usbhsf_pio_prepare_pop:

        /*
         * change handler to PIO
         */
        pkt->handler = &usbhs_fifo_pio_pop_handler;
        usbhs_pipe_config_change_bfre(pipe, 0);

        return pkt->handler->prepare(pkt, is_done);
}

static int usbhsf_dma_prepare_pop(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);

        if (usbhs_get_dparam(priv, has_usb_dmac))
                return usbhsf_dma_prepare_pop_with_usb_dmac(pkt, is_done);
        else
                return usbhsf_dma_prepare_pop_with_rx_irq(pkt, is_done);
}

static int usbhsf_dma_try_pop_with_rx_irq(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo;
        int len, ret;

        if (usbhs_pipe_is_busy(pipe))
                return 0;

        if (usbhs_pipe_is_dcp(pipe))
                goto usbhsf_pio_prepare_pop;

        /* get enable DMA fifo */
        fifo = usbhsf_get_dma_fifo(priv, pkt);
        if (!fifo)
                goto usbhsf_pio_prepare_pop;

        if ((uintptr_t)(pkt->buf + pkt->actual) & 0x7) /* 8byte alignment */
                goto usbhsf_pio_prepare_pop;

        ret = usbhsf_fifo_select(pipe, fifo, 0);
        if (ret < 0)
                goto usbhsf_pio_prepare_pop;

        /* use PIO if packet is less than pio_dma_border */
        len = usbhsf_fifo_rcv_len(priv, fifo);
        len = min(pkt->length - pkt->actual, len);
        if (len & 0x7) /* 8byte alignment */
                goto usbhsf_pio_prepare_pop_unselect;

        if (len < usbhs_get_dparam(priv, pio_dma_border))
                goto usbhsf_pio_prepare_pop_unselect;

        ret = usbhsf_fifo_barrier(priv, fifo);
        if (ret < 0)
                goto usbhsf_pio_prepare_pop_unselect;

        if (usbhsf_dma_map(pkt) < 0)
                goto usbhsf_pio_prepare_pop_unselect;

        /* DMA */

        /*
         * usbhs_fifo_dma_pop_handler :: prepare
         * enabled irq to come here.
         * but it is no longer needed for DMA. disable it.
         */
        usbhsf_rx_irq_ctrl(pipe, 0);

        pkt->trans = len;

        INIT_WORK(&pkt->work, xfer_work);
        schedule_work(&pkt->work);

        return 0;

usbhsf_pio_prepare_pop_unselect:
        usbhsf_fifo_unselect(pipe, fifo);
usbhsf_pio_prepare_pop:

        /*
         * change handler to PIO
         */
        pkt->handler = &usbhs_fifo_pio_pop_handler;

        return pkt->handler->try_run(pkt, is_done);
}

static int usbhsf_dma_try_pop(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);

        BUG_ON(usbhs_get_dparam(priv, has_usb_dmac));

        return usbhsf_dma_try_pop_with_rx_irq(pkt, is_done);
}

static int usbhsf_dma_pop_done_with_rx_irq(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        int maxp = usbhs_pipe_get_maxpacket(pipe);

        usbhsf_dma_stop(pipe, pipe->fifo);
        usbhsf_dma_unmap(pkt);
        usbhsf_fifo_unselect(pipe, pipe->fifo);

        pkt->actual += pkt->trans;

        if ((pkt->actual == pkt->length) ||     /* receive all data */
            (pkt->trans < maxp)) {              /* short packet */
                *is_done = 1;
                usbhs_pipe_running(pipe, 0);
        } else {
                /* re-enable */
                usbhs_pipe_running(pipe, 0);
                usbhsf_prepare_pop(pkt, is_done);
        }

        return 0;
}

static size_t usbhs_dma_calc_received_size(struct usbhs_pkt *pkt,
                                           struct dma_chan *chan, int dtln)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct dma_tx_state state;
        size_t received_size;
        int maxp = usbhs_pipe_get_maxpacket(pipe);

        dmaengine_tx_status(chan, pkt->cookie, &state);
        received_size = pkt->length - state.residue;

        if (dtln) {
                received_size -= USBHS_USB_DMAC_XFER_SIZE;
                received_size &= ~(maxp - 1);
                received_size += dtln;
        }

        return received_size;
}

static int usbhsf_dma_pop_done_with_usb_dmac(struct usbhs_pkt *pkt,
                                             int *is_done)
{
        struct usbhs_pipe *pipe = pkt->pipe;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhs_pipe_to_fifo(pipe);
        struct dma_chan *chan = usbhsf_dma_chan_get(fifo, pkt);
        int rcv_len;

        /*
         * Since the driver disables rx_irq in DMA mode, the interrupt handler
         * cannot the BRDYSTS. So, the function clears it here because the
         * driver may use PIO mode next time.
         */
        usbhs_xxxsts_clear(priv, BRDYSTS, usbhs_pipe_number(pipe));

        rcv_len = usbhsf_fifo_rcv_len(priv, fifo);
        usbhsf_fifo_clear(pipe, fifo);
        pkt->actual = usbhs_dma_calc_received_size(pkt, chan, rcv_len);

        usbhsf_dma_stop(pipe, fifo);
        usbhsf_dma_unmap(pkt);
        usbhsf_fifo_unselect(pipe, pipe->fifo);

        /* The driver can assume the rx transaction is always "done" */
        *is_done = 1;

        return 0;
}

static int usbhsf_dma_pop_done(struct usbhs_pkt *pkt, int *is_done)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pkt->pipe);

        if (usbhs_get_dparam(priv, has_usb_dmac))
                return usbhsf_dma_pop_done_with_usb_dmac(pkt, is_done);
        else
                return usbhsf_dma_pop_done_with_rx_irq(pkt, is_done);
}

const struct usbhs_pkt_handle usbhs_fifo_dma_pop_handler = {
        .prepare        = usbhsf_dma_prepare_pop,
        .try_run        = usbhsf_dma_try_pop,
        .dma_done       = usbhsf_dma_pop_done
};

/*
 *              DMA setting
 */
static bool usbhsf_dma_filter(struct dma_chan *chan, void *param)
{
        struct sh_dmae_slave *slave = param;

        /*
         * FIXME
         *
         * usbhs doesn't recognize id = 0 as valid DMA
         */
        if (0 == slave->shdma_slave.slave_id)
                return false;

        chan->private = slave;

        return true;
}

static void usbhsf_dma_quit(struct usbhs_priv *priv, struct usbhs_fifo *fifo)
{
        if (fifo->tx_chan)
                dma_release_channel(fifo->tx_chan);
        if (fifo->rx_chan)
                dma_release_channel(fifo->rx_chan);

        fifo->tx_chan = NULL;
        fifo->rx_chan = NULL;
}

static void usbhsf_dma_init_pdev(struct usbhs_fifo *fifo)
{
        dma_cap_mask_t mask;

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);
        fifo->tx_chan = dma_request_channel(mask, usbhsf_dma_filter,
                                            &fifo->tx_slave);

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);
        fifo->rx_chan = dma_request_channel(mask, usbhsf_dma_filter,
                                            &fifo->rx_slave);
}

static void usbhsf_dma_init_dt(struct device *dev, struct usbhs_fifo *fifo,
                               int channel)
{
        char name[16];

        /*
         * To avoid complex handing for DnFIFOs, the driver uses each
         * DnFIFO as TX or RX direction (not bi-direction).
         * So, the driver uses odd channels for TX, even channels for RX.
         */
        snprintf(name, sizeof(name), "ch%d", channel);
        if (channel & 1) {
                fifo->tx_chan = dma_request_slave_channel_reason(dev, name);
                if (IS_ERR(fifo->tx_chan))
                        fifo->tx_chan = NULL;
        } else {
                fifo->rx_chan = dma_request_slave_channel_reason(dev, name);
                if (IS_ERR(fifo->rx_chan))
                        fifo->rx_chan = NULL;
        }
}

static void usbhsf_dma_init(struct usbhs_priv *priv, struct usbhs_fifo *fifo,
                            int channel)
{
        struct device *dev = usbhs_priv_to_dev(priv);

        if (dev->of_node)
                usbhsf_dma_init_dt(dev, fifo, channel);
        else
                usbhsf_dma_init_pdev(fifo);

        if (fifo->tx_chan || fifo->rx_chan)
                dev_dbg(dev, "enable DMAEngine (%s%s%s)\n",
                         fifo->name,
                         fifo->tx_chan ? "[TX]" : "    ",
                         fifo->rx_chan ? "[RX]" : "    ");
}

/*
 *              irq functions
 */
static int usbhsf_irq_empty(struct usbhs_priv *priv,
                            struct usbhs_irq_state *irq_state)
{
        struct usbhs_pipe *pipe;
        struct device *dev = usbhs_priv_to_dev(priv);
        int i, ret;

        if (!irq_state->bempsts) {
                dev_err(dev, "debug %s !!\n", __func__);
                return -EIO;
        }

        dev_dbg(dev, "irq empty [0x%04x]\n", irq_state->bempsts);

        /*
         * search interrupted "pipe"
         * not "uep".
         */
        usbhs_for_each_pipe_with_dcp(pipe, priv, i) {
                if (!(irq_state->bempsts & (1 << i)))
                        continue;

                ret = usbhsf_pkt_handler(pipe, USBHSF_PKT_TRY_RUN);
                if (ret < 0)
                        dev_err(dev, "irq_empty run_error %d : %d\n", i, ret);
        }

        return 0;
}

static int usbhsf_irq_ready(struct usbhs_priv *priv,
                            struct usbhs_irq_state *irq_state)
{
        struct usbhs_pipe *pipe;
        struct device *dev = usbhs_priv_to_dev(priv);
        int i, ret;

        if (!irq_state->brdysts) {
                dev_err(dev, "debug %s !!\n", __func__);
                return -EIO;
        }

        dev_dbg(dev, "irq ready [0x%04x]\n", irq_state->brdysts);

        /*
         * search interrupted "pipe"
         * not "uep".
         */
        usbhs_for_each_pipe_with_dcp(pipe, priv, i) {
                if (!(irq_state->brdysts & (1 << i)))
                        continue;

                ret = usbhsf_pkt_handler(pipe, USBHSF_PKT_TRY_RUN);
                if (ret < 0)
                        dev_err(dev, "irq_ready run_error %d : %d\n", i, ret);
        }

        return 0;
}

static void usbhsf_dma_complete(void *arg)
{
        struct usbhs_pipe *pipe = arg;
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct device *dev = usbhs_priv_to_dev(priv);
        int ret;

        ret = usbhsf_pkt_handler(pipe, USBHSF_PKT_DMA_DONE);
        if (ret < 0)
                dev_err(dev, "dma_complete run_error %d : %d\n",
                        usbhs_pipe_number(pipe), ret);
}

void usbhs_fifo_clear_dcp(struct usbhs_pipe *pipe)
{
        struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
        struct usbhs_fifo *fifo = usbhsf_get_cfifo(priv); /* CFIFO */

        /* clear DCP FIFO of transmission */
        if (usbhsf_fifo_select(pipe, fifo, 1) < 0)
                return;
        usbhsf_fifo_clear(pipe, fifo);
        usbhsf_fifo_unselect(pipe, fifo);

        /* clear DCP FIFO of reception */
        if (usbhsf_fifo_select(pipe, fifo, 0) < 0)
                return;
        usbhsf_fifo_clear(pipe, fifo);
        usbhsf_fifo_unselect(pipe, fifo);
}

/*
 *              fifo init
 */
void usbhs_fifo_init(struct usbhs_priv *priv)
{
        struct usbhs_mod *mod = usbhs_mod_get_current(priv);
        struct usbhs_fifo *cfifo = usbhsf_get_cfifo(priv);
        struct usbhs_fifo *dfifo;
        int i;

        mod->irq_empty          = usbhsf_irq_empty;
        mod->irq_ready          = usbhsf_irq_ready;
        mod->irq_bempsts        = 0;
        mod->irq_brdysts        = 0;

        cfifo->pipe     = NULL;
        usbhs_for_each_dfifo(priv, dfifo, i)
                dfifo->pipe     = NULL;
}

void usbhs_fifo_quit(struct usbhs_priv *priv)
{
        struct usbhs_mod *mod = usbhs_mod_get_current(priv);

        mod->irq_empty          = NULL;
        mod->irq_ready          = NULL;
        mod->irq_bempsts        = 0;
        mod->irq_brdysts        = 0;
}

#define __USBHS_DFIFO_INIT(priv, fifo, channel, fifo_port)              \
do {                                                                    \
        fifo = usbhsf_get_dnfifo(priv, channel);                        \
        fifo->name      = "D"#channel"FIFO";                            \
        fifo->port      = fifo_port;                                    \
        fifo->sel       = D##channel##FIFOSEL;                          \
        fifo->ctr       = D##channel##FIFOCTR;                          \
        fifo->tx_slave.shdma_slave.slave_id =                           \
                        usbhs_get_dparam(priv, d##channel##_tx_id);     \
        fifo->rx_slave.shdma_slave.slave_id =                           \
                        usbhs_get_dparam(priv, d##channel##_rx_id);     \
        usbhsf_dma_init(priv, fifo, channel);                           \
} while (0)

#define USBHS_DFIFO_INIT(priv, fifo, channel)                           \
                __USBHS_DFIFO_INIT(priv, fifo, channel, D##channel##FIFO)
#define USBHS_DFIFO_INIT_NO_PORT(priv, fifo, channel)                   \
                __USBHS_DFIFO_INIT(priv, fifo, channel, 0)

int usbhs_fifo_probe(struct usbhs_priv *priv)
{
        struct usbhs_fifo *fifo;

        /* CFIFO */
        fifo = usbhsf_get_cfifo(priv);
        fifo->name      = "CFIFO";
        fifo->port      = CFIFO;
        fifo->sel       = CFIFOSEL;
        fifo->ctr       = CFIFOCTR;

        /* DFIFO */
        USBHS_DFIFO_INIT(priv, fifo, 0);
        USBHS_DFIFO_INIT(priv, fifo, 1);
        USBHS_DFIFO_INIT_NO_PORT(priv, fifo, 2);
        USBHS_DFIFO_INIT_NO_PORT(priv, fifo, 3);

        return 0;
}

void usbhs_fifo_remove(struct usbhs_priv *priv)
{
        struct usbhs_fifo *fifo;
        int i;

        usbhs_for_each_dfifo(priv, fifo, i)
                usbhsf_dma_quit(priv, fifo);
}