[PATCH] gpu: ipu-v3: allocate ipuv3_channels as needed

[Philipp Zabel]

Most of the 64 IPUv3 DMA channels are never used, some of them (channels
16, 30, 32, 34-39, and 53-63) are even marked as reserved.
Allocate the channel control structure only when a channel is actually
requested, replace the fixed size array with a list, and remove the
unused enabled and busy fields from the ipuv3_channel structure.

Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
---
 drivers/gpu/ipu-v3/ipu-common.c | 23 +++++++++++++++--------
 drivers/gpu/ipu-v3/ipu-prv.h    |  8 ++------
 2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/ipu-v3/ipu-common.c b/drivers/gpu/ipu-v3/ipu-common.c
index 67c45fd250291..18ef46fc70860 100644
--- a/drivers/gpu/ipu-v3/ipu-common.c
+++ b/drivers/gpu/ipu-v3/ipu-common.c
@@ -296,15 +296,22 @@ struct ipuv3_channel *ipu_idmac_get(struct ipu_soc *ipu, unsigned num)
 
 	mutex_lock(&ipu->channel_lock);
 
-	channel = &ipu->channel[num];
+	list_for_each_entry(channel, &ipu->channels, list) {
+		if (channel->num == num) {
+			channel = ERR_PTR(-EBUSY);
+			goto out;
+		}
+	}
 
-	if (channel->busy) {
-		channel = ERR_PTR(-EBUSY);
+	channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+	if (!channel) {
+		channel = ERR_PTR(-ENOMEM);
 		goto out;
 	}
 
-	channel->busy = true;
 	channel->num = num;
+	channel->ipu = ipu;
+	list_add(&channel->list, &ipu->channels);
 
 out:
 	mutex_unlock(&ipu->channel_lock);
@@ -321,7 +328,8 @@ void ipu_idmac_put(struct ipuv3_channel *channel)
 
 	mutex_lock(&ipu->channel_lock);
 
-	channel->busy = false;
+	list_del(&channel->list);
+	kfree(channel);
 
 	mutex_unlock(&ipu->channel_lock);
 }
@@ -1400,7 +1408,7 @@ static int ipu_probe(struct platform_device *pdev)
 	struct ipu_soc *ipu;
 	struct resource *res;
 	unsigned long ipu_base;
-	int i, ret, irq_sync, irq_err;
+	int ret, irq_sync, irq_err;
 	const struct ipu_devtype *devtype;
 
 	devtype = of_device_get_match_data(&pdev->dev);
@@ -1433,13 +1441,12 @@ static int ipu_probe(struct platform_device *pdev)
 			return -EPROBE_DEFER;
 	}
 
-	for (i = 0; i < 64; i++)
-		ipu->channel[i].ipu = ipu;
 	ipu->devtype = devtype;
 	ipu->ipu_type = devtype->type;
 
 	spin_lock_init(&ipu->lock);
 	mutex_init(&ipu->channel_lock);
+	INIT_LIST_HEAD(&ipu->channels);
 
 	dev_dbg(&pdev->dev, "cm_reg:   0x%08lx\n",
 			ipu_base + devtype->cm_ofs);
diff --git a/drivers/gpu/ipu-v3/ipu-prv.h b/drivers/gpu/ipu-v3/ipu-prv.h
index 3a579e35de584..13194e1e1621a 100644
--- a/drivers/gpu/ipu-v3/ipu-prv.h
+++ b/drivers/gpu/ipu-v3/ipu-prv.h
@@ -157,11 +157,8 @@ enum ipu_modules {
 
 struct ipuv3_channel {
 	unsigned int num;
-
-	bool enabled;
-	bool busy;
-
 	struct ipu_soc *ipu;
+	struct list_head list;
 };
 
 struct ipu_cpmem;
@@ -184,6 +181,7 @@ struct ipu_soc {
 	enum ipuv3_type		ipu_type;
 	spinlock_t		lock;
 	struct mutex		channel_lock;
+	struct list_head	channels;
 
 	void __iomem		*cm_reg;
 	void __iomem		*idmac_reg;
@@ -193,8 +191,6 @@ struct ipu_soc {
 
 	struct clk		*clk;
 
-	struct ipuv3_channel	channel[64];
-
 	int			irq_sync;
 	int			irq_err;
 	struct irq_domain	*domain;
-- 
2.11.0