trigger fire: check if trigger is busy

When a trigger fire it is set to STATUS_ON until data_done(); so, one
transfer at time is allowed.

Signed-off-by: Federico Vaga <federico.vaga@gmail.com>
Acked-by: Alessandro Rubini <rubini@gnudd.com>

include/linux/zio-trigger.h

@@ -51,6 +51,14 @@ struct zio_ti {
 	const struct file_operations		*f_op;
 
 };
+
+/* first 4bit are reserved for zio object universal flags */
+enum zti_flag_mask {
+	ZTI_STATUS = 0x10,
+	ZTI_STATUS_OFF = 0x00,	/* trigger is idle */
+	ZTI_STATUS_ON = 0x10,	/* trigger fire and transfer occurs */
+};
+
 #define to_zio_ti(_kobj) container_of(_kobj, struct zio_ti, head.kobj)
 void zio_fire_trigger(struct zio_ti *ti);
 

zio-sys.c

@@ -122,7 +122,7 @@ void zio_generic_data_done(struct zio_cset *cset)
 			/* We may have a new block ready, or not */
 			chan->active_block = zbuf->b_op->retr_block(chan->bi);
 		}
-		return;
+		goto out;
 	}
 	/* DIR_INPUT */
 	cset_for_each(cset, chan) {
@@ -133,6 +133,8 @@ void zio_generic_data_done(struct zio_cset *cset)
 		if (zbuf->b_op->store_block(bi, block)) /* may fail, no prob */
 			zbuf->b_op->free_block(bi, block);
 	}
+out:
+	ti->flags &= (~ZTI_STATUS);
 }
 EXPORT_SYMBOL(zio_generic_data_done);
 
@@ -152,8 +154,6 @@ static void __zio_fire_input_trigger(struct zio_ti *ti)
 
 	pr_debug("%s:%d\n", __func__, __LINE__);
 
-	/* FIXME: check if a trigger is already pending */
-
 	/* Allocate the buffer for the incoming sample, in active channels */
 	cset_for_each(cset, chan) {
 		ctrl = zio_alloc_control(GFP_ATOMIC);
@@ -204,7 +204,10 @@ void zio_fire_trigger(struct zio_ti *ti)
 	/* If the trigger runs too early, ti->cset is still NULL */
 	if (!ti->cset)
 		return;
-
+	/* check if previouvs fire is still running*/
+	if ((ti->flags & ZTI_STATUS) == ZTI_STATUS_ON)
+		return;
+	ti->flags |= ZTI_STATUS_ON;
 	/* Copy the stamp (we are software driven anyways) */
 	ti->current_ctrl->tstamp.secs = ti->tstamp.tv_sec;
 	ti->current_ctrl->tstamp.ticks = ti->tstamp.tv_nsec;