[PATCH 1/3] dmaengine: pl330: Set residue in tx_status callback.

[Padmavathi Venna]

From: Dylan Reid <dgreid at chromium.org>

Fill txstate.residue with the amount of bytes remaining in the current
transfer if the transfer is not complete.  This will be of particular
use to i2s DMA transfers, providing more accurate hw_ptr values to ASoC.

Signed-off-by: Dylan Reid <dgreid at chromium.org>
Reviewed-by: Olof Johansson <olofj at chromium.org>
Signed-off-by: Padmavathi Venna <padma.v at samsung.com>
---
 drivers/dma/pl330.c |   55 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 54 insertions(+), 1 deletions(-)

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 593827b..7ab9136 100644
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -2476,11 +2476,64 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
 	spin_unlock_irqrestore(&pch->lock, flags);
 }
 
+static inline int
+pl330_src_addr_in_desc(struct dma_pl330_desc *desc, unsigned int sar)
+{
+	return ((desc->px.src_addr <= sar) &&
+		(sar <= (desc->px.src_addr + desc->px.bytes)));
+}
+
+static inline int
+pl330_dst_addr_in_desc(struct dma_pl330_desc *desc, unsigned int dar)
+{
+	return ((desc->px.dst_addr <= dar) &&
+		(dar <= (desc->px.dst_addr + desc->px.bytes)));
+}
+
+static unsigned int pl330_tx_residue(struct dma_chan *chan)
+{
+	struct dma_pl330_chan *pch = to_pchan(chan);
+	void __iomem *regs = pch->dmac->pif.base;
+	struct pl330_thread *thrd = pch->pl330_chid;
+	struct dma_pl330_desc *desc;
+	unsigned int sar, dar;
+	unsigned int residue = 0;
+	unsigned long flags;
+
+	sar = readl(regs + SA(thrd->id));
+	dar = readl(regs + DA(thrd->id));
+
+	spin_lock_irqsave(&pch->lock, flags);
+
+	/* Find the desc related to the current buffer. */
+	list_for_each_entry(desc, &pch->work_list, node) {
+		if (desc->rqcfg.src_inc && pl330_src_addr_in_desc(desc, sar)) {
+			residue = desc->px.bytes - (sar - desc->px.src_addr);
+			goto found_unlock;
+		}
+		if (desc->rqcfg.dst_inc && pl330_dst_addr_in_desc(desc, dar)) {
+			residue = desc->px.bytes - (dar - desc->px.dst_addr);
+			goto found_unlock;
+		}
+	}
+
+found_unlock:
+	spin_unlock_irqrestore(&pch->lock, flags);
+
+	return residue;
+}
+
 static enum dma_status
 pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,
 		 struct dma_tx_state *txstate)
 {
-	return dma_cookie_status(chan, cookie, txstate);
+	enum dma_status ret;
+
+	ret = dma_cookie_status(chan, cookie, txstate);
+	if (ret != DMA_SUCCESS) /* Not complete, check amount left. */
+		dma_set_residue(txstate, pl330_tx_residue(chan));
+
+	return ret;
 }
 
 static void pl330_issue_pending(struct dma_chan *chan)
-- 
1.7.4.4