[PATCH 2/3] ARM: edma: Add edma_assign_channel_eventq() to move channel to a give queue

[Peter Ujfalusi]

In some cases it is desired to move a channel to a specific event queue.
Such a use case is audio, where it is preferred that it is served with
highest priority compared to other DMA clients.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
---
 arch/arm/common/edma.c             | 28 ++++++++++++++++++++++++++++
 include/linux/platform_data/edma.h |  2 ++
 2 files changed, 30 insertions(+)

diff --git a/arch/arm/common/edma.c b/arch/arm/common/edma.c
index f834aae7720f..88099175fc56 100644
--- a/arch/arm/common/edma.c
+++ b/arch/arm/common/edma.c
@@ -1414,6 +1414,34 @@ void edma_clear_event(unsigned channel)
 }
 EXPORT_SYMBOL(edma_clear_event);
 
+/*
+ * edma_assign_channel_eventq - move given channel to desired eventq
+ * Arguments:
+ *	channel - channel number
+ *	eventq_no - queue to move the channel
+ *
+ * Can be used to move a channel to a selected event queue.
+ */
+void edma_assign_channel_eventq(unsigned channel, enum dma_event_q eventq_no)
+{
+	unsigned ctlr;
+
+	ctlr = EDMA_CTLR(channel);
+	channel = EDMA_CHAN_SLOT(channel);
+
+	if (channel >= edma_cc[ctlr]->num_channels)
+		return;
+
+	/* default to low priority queue */
+	if (eventq_no == EVENTQ_DEFAULT)
+		eventq_no = edma_cc[ctlr]->default_queue;
+	if (eventq_no >= edma_cc[ctlr]->num_tc)
+		return;
+
+	map_dmach_queue(ctlr, channel, eventq_no);
+}
+EXPORT_SYMBOL(edma_assign_channel_eventq);
+
 static int edma_setup_from_hw(struct device *dev, struct edma_soc_info *pdata,
 			      struct edma *edma_cc)
 {
diff --git a/include/linux/platform_data/edma.h b/include/linux/platform_data/edma.h
index eb8d5627d080..bdb2710e2aab 100644
--- a/include/linux/platform_data/edma.h
+++ b/include/linux/platform_data/edma.h
@@ -150,6 +150,8 @@ void edma_clear_event(unsigned channel);
 void edma_pause(unsigned channel);
 void edma_resume(unsigned channel);
 
+void edma_assign_channel_eventq(unsigned channel, enum dma_event_q eventq_no);
+
 struct edma_rsv_info {
 
 	const s16	(*rsv_chans)[2];
-- 
2.0.0

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