bestcomm.h

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/*
 * Public header for the MPC52xx processor BestComm driver
 *
 *
 * Copyright (C) 2006      Sylvain Munaut <[email protected]>
 * Copyright (C) 2005      Varma Electronics Oy,
 *                         ( by Andrey Volkov <[email protected]> )
 * Copyright (C) 2003-2004 MontaVista, Software, Inc.
 *                         ( by Dale Farnsworth <[email protected]> )
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#ifndef __BESTCOMM_H__
#define __BESTCOMM_H__

struct bcom_bd {
    u32 status;
    u32 data[0];    /* variable payload size */
};

/* ======================================================================== */
/* Generic task management                                                   */
/* ======================================================================== */

struct bcom_task {
    unsigned int    tasknum;
    unsigned int    flags;
    int     irq;

    struct bcom_bd  *bd;
    phys_addr_t bd_pa;
    void        **cookie;
    unsigned short  index;
    unsigned short  outdex;
    unsigned int    num_bd;
    unsigned int    bd_size;

    void*       priv;
};

#define BCOM_FLAGS_NONE         0x00000000ul
#define BCOM_FLAGS_ENABLE_TASK  (1ul <<  0)

extern void bcom_enable(struct bcom_task *tsk);

extern void bcom_disable(struct bcom_task *tsk);


static inline int
bcom_get_task_irq(struct bcom_task *tsk) {
    return tsk->irq;
}

/* ======================================================================== */
/* BD based tasks helpers                                                   */
/* ======================================================================== */

#define BCOM_BD_READY   0x40000000ul

static inline int
_bcom_next_index(struct bcom_task *tsk)
{
    return ((tsk->index + 1) == tsk->num_bd) ? 0 : tsk->index + 1;
}

static inline int
_bcom_next_outdex(struct bcom_task *tsk)
{
    return ((tsk->outdex + 1) == tsk->num_bd) ? 0 : tsk->outdex + 1;
}

static inline int
bcom_queue_empty(struct bcom_task *tsk)
{
    return tsk->index == tsk->outdex;
}

static inline int
bcom_queue_full(struct bcom_task *tsk)
{
    return tsk->outdex == _bcom_next_index(tsk);
}

static inline struct bcom_bd
*bcom_get_bd(struct bcom_task *tsk, unsigned int index)
{
    /* A cast to (void*) so the address can be incremented by the
     * real size instead of by sizeof(struct bcom_bd) */
    return ((void *)tsk->bd) + (index * tsk->bd_size);
}

static inline int
bcom_buffer_done(struct bcom_task *tsk)
{
    struct bcom_bd *bd;
    if (bcom_queue_empty(tsk))
        return 0;

    bd = bcom_get_bd(tsk, tsk->outdex);
    return !(bd->status & BCOM_BD_READY);
}

static inline struct bcom_bd *
bcom_prepare_next_buffer(struct bcom_task *tsk)
{
    struct bcom_bd *bd;

    bd = bcom_get_bd(tsk, tsk->index);
    bd->status = 0; /* cleanup last status */
    return bd;
}

static inline void
bcom_submit_next_buffer(struct bcom_task *tsk, void *cookie)
{
    struct bcom_bd *bd = bcom_get_bd(tsk, tsk->index);

    tsk->cookie[tsk->index] = cookie;
    mb();   /* ensure the bd is really up-to-date */
    bd->status |= BCOM_BD_READY;
    tsk->index = _bcom_next_index(tsk);
    if (tsk->flags & BCOM_FLAGS_ENABLE_TASK)
        bcom_enable(tsk);
}

static inline void *
bcom_retrieve_buffer(struct bcom_task *tsk, u32 *p_status, struct bcom_bd **p_bd)
{
    void *cookie = tsk->cookie[tsk->outdex];
    struct bcom_bd *bd = bcom_get_bd(tsk, tsk->outdex);

    if (p_status)
        *p_status = bd->status;
    if (p_bd)
        *p_bd = bd;
    tsk->outdex = _bcom_next_outdex(tsk);
    return cookie;
}

#endif /* __BESTCOMM_H__ */