/*
* 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 - Structure describing a generic BestComm buffer descriptor
* @status: The current status of this buffer. Exact meaning depends on the
* task type
* @data: An array of u32 extra data. Size of array is task dependent.
*
* Note: Don't dereference a bcom_bd pointer as an array. The size of the
* bcom_bd is variable. Use bcom_get_bd() instead.
*/
struct bcom_bd {
u32 status;
u32 data[0]; /* variable payload size */
};

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

/**
* struct bcom_task - Structure describing a loaded BestComm task
*
* This structure is never built by the driver it self. It's built and
* filled the intermediate layer of the BestComm API, the task dependent
* support code.
*
* Most likely you don't need to poke around inside this structure. The
* fields are exposed in the header just for the sake of inline functions
*/
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)

/**
* bcom_enable - Enable a BestComm task
* @tsk: The BestComm task structure
*
* This function makes sure the given task is enabled and can be run
* by the BestComm engine as needed
*/
extern void bcom_enable(struct bcom_task *tsk);

/**
* bcom_disable - Disable a BestComm task
* @tsk: The BestComm task structure
*
* This function disable a given task, making sure it's not executed
* by the BestComm engine.
*/
extern void bcom_disable(struct bcom_task *tsk);


/**
* bcom_get_task_irq - Returns the irq number of a BestComm task
* @tsk: The BestComm task structure
*/
static inline int
bcom_get_task_irq(struct bcom_task *tsk) {
return tsk->irq;
}

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

#define BCOM_BD_READY 0x40000000ul

/** _bcom_next_index - Get next input index.
* @tsk: pointer to task structure
*
* Support function; Device drivers should not call this
*/
static inline int
_bcom_next_index(struct bcom_task *tsk)
{
return ((tsk->index + 1) == tsk->num_bd) ? 0 : tsk->index + 1;
}

/** _bcom_next_outdex - Get next output index.
* @tsk: pointer to task structure
*
* Support function; Device drivers should not call this
*/
static inline int
_bcom_next_outdex(struct bcom_task *tsk)
{
return ((tsk->outdex + 1) == tsk->num_bd) ? 0 : tsk->outdex + 1;
}

/**
* bcom_queue_empty - Checks if a BestComm task BD queue is empty
* @tsk: The BestComm task structure
*/
static inline int
bcom_queue_empty(struct bcom_task *tsk)
{
return tsk->index == tsk->outdex;
}

/**
* bcom_queue_full - Checks if a BestComm task BD queue is full
* @tsk: The BestComm task structure
*/
static inline int
bcom_queue_full(struct bcom_task *tsk)
{
return tsk->outdex == _bcom_next_index(tsk);
}

/**
* bcom_get_bd - Get a BD from the queue
* @tsk: The BestComm task structure
* index: Index of the BD to fetch
*/
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);
}

/**
* bcom_buffer_done - Checks if a BestComm
* @tsk: The BestComm task structure
*/
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);
}

/**
* bcom_prepare_next_buffer - clear status of next available buffer.
* @tsk: The BestComm task structure
*
* Returns pointer to next buffer descriptor
*/
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__ */