diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/sysdev/bestcomm/bestcomm.h | 61 |
1 files changed, 42 insertions, 19 deletions
diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm.h b/arch/powerpc/sysdev/bestcomm/bestcomm.h index c960a8b4965..23a95f80dfd 100644 --- a/arch/powerpc/sysdev/bestcomm/bestcomm.h +++ b/arch/powerpc/sysdev/bestcomm/bestcomm.h @@ -16,8 +16,19 @@ #ifndef __BESTCOMM_H__ #define __BESTCOMM_H__ -struct bcom_bd; /* defined later on ... */ - +/** + * 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 dependant. + * + * 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 */ @@ -84,17 +95,6 @@ bcom_get_task_irq(struct bcom_task *tsk) { /* BD based tasks helpers */ /* ======================================================================== */ -/** - * 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 whose meaning depends on the task type. - */ -struct bcom_bd { - u32 status; - u32 data[1]; /* variable, but at least 1 */ -}; - #define BCOM_BD_READY 0x40000000ul /** _bcom_next_index - Get next input index. @@ -140,15 +140,31 @@ bcom_queue_full(struct bcom_task *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; - return !(tsk->bd[tsk->outdex].status & BCOM_BD_READY); + + bd = bcom_get_bd(tsk, tsk->outdex); + return !(bd->status & BCOM_BD_READY); } /** @@ -160,16 +176,21 @@ bcom_buffer_done(struct bcom_task *tsk) static inline struct bcom_bd * bcom_prepare_next_buffer(struct bcom_task *tsk) { - tsk->bd[tsk->index].status = 0; /* cleanup last status */ - return &tsk->bd[tsk->index]; + 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 */ - tsk->bd[tsk->index].status |= BCOM_BD_READY; + bd->status |= BCOM_BD_READY; tsk->index = _bcom_next_index(tsk); if (tsk->flags & BCOM_FLAGS_ENABLE_TASK) bcom_enable(tsk); @@ -179,10 +200,12 @@ 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 = tsk->bd[tsk->outdex].status; + *p_status = bd->status; if (p_bd) - *p_bd = &tsk->bd[tsk->outdex]; + *p_bd = bd; tsk->outdex = _bcom_next_outdex(tsk); return cookie; } |