fifo.c

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/*
 * Renesas USB driver
 *
 * Copyright (C) 2011 Renesas Solutions Corp.
 * Kuninori Morimoto <[email protected]>
 *
 * 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_get_d0fifo(p)    (&((p)->fifo_info.d0fifo))
#define usbhsf_get_d1fifo(p)    (&((p)->fifo_info.d1fifo))
#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)
{
    pkt->dma = DMA_ADDR_INVALID;
    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 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)
{
    if (list_empty(&pipe->list))
        return NULL;

    return list_first_entry(&pipe->list, struct usbhs_pkt, node);
}

struct usbhs_pkt *usbhs_pkt_pop(struct usbhs_pipe *pipe, struct usbhs_pkt *pkt)
{
    struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
    unsigned long flags;

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

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

    if (pkt)
        __usbhsf_pkt_del(pkt);

    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 hander\n");
        goto __usbhs_pkt_handler_end;
    }

    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, bempsts, e)
#define usbhsf_irq_ready_ctrl(p, e) usbhsf_irq_callback_ctrl(p, 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->irq_##status |= status;            \
        else                            \
            mod->irq_##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;
}

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

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);
}

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);
}

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 */

    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_enable(pipe);

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

    /*
     * Transmission end
     */
    if (*is_done) {
        if (usbhs_pipe_is_dcp(pipe))
            usbhs_dcp_control_transfer_done(pipe);
    }

    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);

    return ret;
}

struct usbhs_pkt_handle usbhs_fifo_pio_push_handler = {
    .prepare = usbhsf_pio_try_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;

    if (usbhs_pipe_is_busy(pipe))
        return 0;

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

    usbhs_pipe_enable(pipe);
    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_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;
}

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;
}

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;

    /* DMA :: D0FIFO */
    fifo = usbhsf_get_d0fifo(priv);
    if (usbhsf_dma_chan_get(fifo, pkt) &&
        !usbhsf_fifo_is_busy(fifo))
        return fifo;

    /* DMA :: D1FIFO */
    fifo = usbhsf_get_d1fifo(priv);
    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);
}

#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_pipe *pipe = pkt->pipe;
    struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
    struct usbhs_pipe_info *info = usbhs_priv_to_pipeinfo(priv);

    return info->dma_map_ctrl(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 = usbhs_pipe_to_fifo(pipe);
    struct usbhs_priv *priv = usbhs_pipe_to_priv(pipe);
    struct dma_async_tx_descriptor *desc;
    struct dma_chan *chan = usbhsf_dma_chan_get(fifo, pkt);
    struct device *dev = usbhs_priv_to_dev(priv);
    enum dma_transfer_direction dir;

    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)
        return;

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

    if (dmaengine_submit(desc) < 0) {
        dev_err(dev, "Failed to submit dma descriptor\n");
        return;
    }

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

    usbhs_pipe_enable(pipe);
    usbhsf_dma_start(pipe, fifo);
    dma_async_issue_pending(chan);
}

/*
 *      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;

    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_is_dcp(pipe))
        goto usbhsf_pio_prepare_push;

    if (len & 0x7) /* 8byte alignment */
        goto usbhsf_pio_prepare_push;

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

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

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

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

    pkt->trans = len;

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

    return 0;

usbhsf_pio_prepare_push_unmap:
    usbhsf_dma_unmap(pkt);
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;

    pkt->actual = pkt->trans;

    *is_done = !pkt->zero;  /* send zero packet ? */

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

    return 0;
}

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_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 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_pop_done(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;
    } else {
        /* re-enable */
        usbhsf_prepare_pop(pkt, is_done);
    }

    return 0;
}

struct usbhs_pkt_handle usbhs_fifo_dma_pop_handler = {
    .prepare    = usbhsf_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(struct usbhs_priv *priv,
                struct usbhs_fifo *fifo)
{
    struct device *dev = usbhs_priv_to_dev(priv);
    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);

    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);
}

/*
 *      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 *d0fifo = usbhsf_get_d0fifo(priv);
    struct usbhs_fifo *d1fifo = usbhsf_get_d1fifo(priv);

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

    cfifo->pipe = NULL;
    cfifo->tx_chan  = NULL;
    cfifo->rx_chan  = NULL;

    d0fifo->pipe    = NULL;
    d0fifo->tx_chan = NULL;
    d0fifo->rx_chan = NULL;

    d1fifo->pipe    = NULL;
    d1fifo->tx_chan = NULL;
    d1fifo->rx_chan = NULL;

    usbhsf_dma_init(priv, usbhsf_get_d0fifo(priv));
    usbhsf_dma_init(priv, usbhsf_get_d1fifo(priv));
}

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;

    usbhsf_dma_quit(priv, usbhsf_get_d0fifo(priv));
    usbhsf_dma_quit(priv, usbhsf_get_d1fifo(priv));
}

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;

    /* D0FIFO */
    fifo = usbhsf_get_d0fifo(priv);
    fifo->name  = "D0FIFO";
    fifo->port  = D0FIFO;
    fifo->sel   = D0FIFOSEL;
    fifo->ctr   = D0FIFOCTR;
    fifo->tx_slave.shdma_slave.slave_id = usbhs_get_dparam(priv, d0_tx_id);
    fifo->rx_slave.shdma_slave.slave_id = usbhs_get_dparam(priv, d0_rx_id);

    /* D1FIFO */
    fifo = usbhsf_get_d1fifo(priv);
    fifo->name  = "D1FIFO";
    fifo->port  = D1FIFO;
    fifo->sel   = D1FIFOSEL;
    fifo->ctr   = D1FIFOCTR;
    fifo->tx_slave.shdma_slave.slave_id = usbhs_get_dparam(priv, d1_tx_id);
    fifo->rx_slave.shdma_slave.slave_id = usbhs_get_dparam(priv, d1_rx_id);

    return 0;
}

void usbhs_fifo_remove(struct usbhs_priv *priv)
{
}