[PATCH 1/3] ipu-idmac: new channel status flag, more debugging output

[Guennadi Liakhovetski <lg@xxxxxxx>]

The new status flag IPU_CHANNEL_FREE_PENDING is needed to prevent 
use-count underflow. Also fix missing new-line in debugging prints.

Signed-off-by: Guennadi Liakhovetski <lg@xxxxxxx>
---
diff --git a/arch/arm/plat-mxc/include/mach/ipu.h b/arch/arm/plat-mxc/include/mach/ipu.h
index 07939b9..b9ef451 100644
--- a/arch/arm/plat-mxc/include/mach/ipu.h
+++ b/arch/arm/plat-mxc/include/mach/ipu.h
@@ -54,6 +54,7 @@ enum ipu_channel {
 /* Order significant! */
 enum ipu_channel_status {
 	IPU_CHANNEL_FREE,
+	IPU_CHANNEL_FREE_PENDING,
 	IPU_CHANNEL_GRANTED,
 	IPU_CHANNEL_INITIALIZED,
 	IPU_CHANNEL_READY,
diff --git a/drivers/mfd/ipu/ipu_idmac.c b/drivers/mfd/ipu/ipu_idmac.c
index c7413e7..c0207b0 100644
--- a/drivers/mfd/ipu/ipu_idmac.c
+++ b/drivers/mfd/ipu/ipu_idmac.c
@@ -64,14 +64,14 @@ static void idmac_write_ipureg(struct ipu *ipu, u32 value, unsigned long reg)
 static void dump_idmac_reg(struct ipu *ipu)
 {
 	dev_dbg(ipu->dev, "IDMAC_CONF 0x%x, IC_CONF 0x%x, IDMAC_CHA_EN 0x%x, "
-		"IDMAC_CHA_PRI 0x%x, IDMAC_CHA_BUSY 0x%x",
+		"IDMAC_CHA_PRI 0x%x, IDMAC_CHA_BUSY 0x%x\n",
 		idmac_read_icreg(ipu, IDMAC_CONF),
 		idmac_read_icreg(ipu, IC_CONF),
 		idmac_read_icreg(ipu, IDMAC_CHA_EN),
 		idmac_read_icreg(ipu, IDMAC_CHA_PRI),
 		idmac_read_icreg(ipu, IDMAC_CHA_BUSY));
 	dev_dbg(ipu->dev, "BUF0_RDY 0x%x, BUF1_RDY 0x%x, CUR_BUF 0x%x, "
-		"DB_MODE 0x%x, TASKS_STAT 0x%x",
+		"DB_MODE 0x%x, TASKS_STAT 0x%x\n",
 		idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY),
 		idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY),
 		idmac_read_ipureg(ipu, IPU_CHA_CUR_BUF),
@@ -1364,8 +1364,10 @@ static int idmac_alloc_chan_resources(struct dma_chan *chan,
 	 * Only client_count can tell us whether the channel is free. There is
 	 * no other way to find out if a client has accepted a channel offer.
 	 */
-	if (chan->client_count)
+	if (chan->client_count) {
+		dev_dbg(&chan->dev, "Channel %x busy\n", chan->chan_id);
 		return -EBUSY;
+	}
 
 	/* Now we know, that the channel is free */
 
@@ -1376,9 +1378,14 @@ static int idmac_alloc_chan_resources(struct dma_chan *chan,
 	if (!idmac_client_channel_match(ichan, client))
 		return -EINVAL;
 
-	dev_dbg(&ichan->dma_chan.dev, "Found channel 0x%x for client %p, irq %d\n",
-		ichan->dma_chan.chan_id, client, ichan->eof_irq);
+	dev_dbg(&chan->dev, "Found channel 0x%x for client %p, irq %d\n",
+		chan->chan_id, client, ichan->eof_irq);
 
+	/*
+	 * No real resource allocation here, because we do not know, whether
+	 * the client will accept our offer. Just keep a pointer to the client
+	 * as a hint.
+	 */
 	ichan->iclient = iclient;
 
 	return 0;
@@ -1400,7 +1407,13 @@ static void idmac_free_chan_resources(struct dma_chan *chan)
 
 	for (i = 0, ic = iclient->channels; i < iclient->n_channels; i++, ic++) {
 		if (ic->channel == ichan->dma_chan.chan_id) {
-			ichan->status = IPU_CHANNEL_FREE;
+			dev_dbg(&chan->dev, "Releasing channel %x status %d\n",
+				ic->channel, ichan->status);
+			/*
+			 * The client has to be able to detect when it has to
+			 * ack, that is why we need a special status here.
+			 */
+			ichan->status = IPU_CHANNEL_FREE_PENDING;
 			ic->ichannel = NULL;
 			break;
 		}

--
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