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-rw-r--r--arch/powerpc/sysdev/bestcomm/bestcomm.h61
1 files changed, 42 insertions, 19 deletions
diff --git a/arch/powerpc/sysdev/bestcomm/bestcomm.h b/arch/powerpc/sysdev/bestcomm/bestcomm.h
index c960a8b49655..23a95f80dfdb 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;
}