[PATCH v3 1/5] dmaengine: sh: rz-dmac: Add rz_dmac_invalidate_lmdesc()

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

rz_dmac_terminate_all() must invalidate lmdescriptor in order to
reuse the hardware descriptors in rz_dmac_lmdesc_recycle().

Add rz_dmac_invalidate_lmdesc() so that the same code can be shared
between rz_dmac_terminate_all() and rz_dmac_free_chan_resources().

Based on a patch in the BSP by Long Luu
<long.luu.ur@xxxxxxxxxxx>

Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
---
v2->v3:
 * No change.
v1->v2:
 * Introduced rz_dmac_invalidate_lmdesc(), so that same code is shared
   between rz_dmac_free_chan_resources() and rz_dmac_terminate_all()
   for invalidating hardware descriptors.
 * updated commit description.
---
 drivers/dma/sh/rz-dmac.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index 9479f29692d3..81e72529f7d3 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -236,6 +236,16 @@ static void rz_lmdesc_setup(struct rz_dmac_chan *channel,
  * Descriptors preparation
  */
 
+static void rz_dmac_invalidate_lmdesc(struct rz_dmac_chan *channel)
+{
+	struct rz_lmdesc *lmdesc = channel->lmdesc.base;
+
+	for (; lmdesc < channel->lmdesc.base + DMAC_NR_LMDESC; lmdesc++) {
+		if (lmdesc->header)
+			lmdesc->header = 0;
+	}
+}
+
 static void rz_dmac_lmdesc_recycle(struct rz_dmac_chan *channel)
 {
 	struct rz_lmdesc *lmdesc = channel->lmdesc.head;
@@ -437,16 +447,11 @@ static void rz_dmac_free_chan_resources(struct dma_chan *chan)
 {
 	struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
 	struct rz_dmac *dmac = to_rz_dmac(chan->device);
-	struct rz_lmdesc *lmdesc = channel->lmdesc.base;
 	struct rz_dmac_desc *desc, *_desc;
 	unsigned long flags;
-	unsigned int i;
 
 	spin_lock_irqsave(&channel->vc.lock, flags);
-
-	for (i = 0; i < DMAC_NR_LMDESC; i++)
-		lmdesc[i].header = 0;
-
+	rz_dmac_invalidate_lmdesc(channel);
 	rz_dmac_disable_hw(channel);
 	list_splice_tail_init(&channel->ld_active, &channel->ld_free);
 	list_splice_tail_init(&channel->ld_queue, &channel->ld_free);
@@ -537,6 +542,7 @@ static int rz_dmac_terminate_all(struct dma_chan *chan)
 
 	rz_dmac_disable_hw(channel);
 	spin_lock_irqsave(&channel->vc.lock, flags);
+	rz_dmac_invalidate_lmdesc(channel);
 	list_splice_tail_init(&channel->ld_active, &channel->ld_free);
 	list_splice_tail_init(&channel->ld_queue, &channel->ld_free);
 	spin_unlock_irqrestore(&channel->vc.lock, flags);
-- 
2.25.1