[PATCH 2/6] mailbox: ti-msgmgr: Allocate Rx channel resources only on request

[Nishanth Menon]

In a much bigger system SoCs, the number of Rx channels can be
many and mostly unused based on the system of choice, and not all
Rx channels need IRQs and allocating all memory at probe will be
inefficient. Some SoCs could have total threads in the 100s and usage
would be just 1 Rx thread.

Thus, request and map the IRQs and allocate memory only when needed.

Since these channels are requested by client drivers on need, our
utilization will be optimal.

Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
Changes since RFC: None
RFC: https://patchwork.kernel.org/patch/10447701/

 drivers/mailbox/ti-msgmgr.c | 91 ++++++++++++++++++++++++++++++---------------
 1 file changed, 61 insertions(+), 30 deletions(-)

diff --git a/drivers/mailbox/ti-msgmgr.c b/drivers/mailbox/ti-msgmgr.c
index 5fe6ce200264..91c955979008 100644
--- a/drivers/mailbox/ti-msgmgr.c
+++ b/drivers/mailbox/ti-msgmgr.c
@@ -310,6 +310,51 @@ static int ti_msgmgr_send_data(struct mbox_chan *chan, void *data)
 	return 0;
 }
 
+/**
+ *  ti_msgmgr_queue_rx_irq_req() - RX IRQ request
+ *  @dev:	device pointer
+ *  @qinst:	Queue instance
+ *  @chan:	Channel pointer
+ */
+static int ti_msgmgr_queue_rx_irq_req(struct device *dev,
+				      struct ti_queue_inst *qinst,
+				      struct mbox_chan *chan)
+{
+	int ret = 0;
+	char of_rx_irq_name[7];
+	struct device_node *np;
+
+	snprintf(of_rx_irq_name, sizeof(of_rx_irq_name),
+		 "rx_%03d", qinst->queue_id);
+
+	/* Get the IRQ if not found */
+	if (qinst->irq < 0) {
+		np = of_node_get(dev->of_node);
+		if (!np)
+			return -ENODATA;
+		qinst->irq = of_irq_get_byname(np, of_rx_irq_name);
+		of_node_put(np);
+
+		if (qinst->irq < 0) {
+			dev_err(dev,
+				"QID %d PID %d:No IRQ[%s]: %d\n",
+				qinst->queue_id, qinst->proxy_id,
+				of_rx_irq_name, qinst->irq);
+			return qinst->irq;
+		}
+	}
+
+	/* With the expectation that the IRQ might be shared in SoC */
+	ret = request_irq(qinst->irq, ti_msgmgr_queue_rx_interrupt,
+			  IRQF_SHARED, qinst->name, chan);
+	if (ret) {
+		dev_err(dev, "Unable to get IRQ %d on %s(res=%d)\n",
+			qinst->irq, qinst->name, ret);
+	}
+
+	return ret;
+}
+
 /**
  * ti_msgmgr_queue_startup() - Startup queue
  * @chan:	Channel pointer
@@ -318,19 +363,21 @@ static int ti_msgmgr_send_data(struct mbox_chan *chan, void *data)
  */
 static int ti_msgmgr_queue_startup(struct mbox_chan *chan)
 {
-	struct ti_queue_inst *qinst = chan->con_priv;
 	struct device *dev = chan->mbox->dev;
+	struct ti_msgmgr_inst *inst = dev_get_drvdata(dev);
+	struct ti_queue_inst *qinst = chan->con_priv;
+	const struct ti_msgmgr_desc *d = inst->desc;
 	int ret;
 
 	if (!qinst->is_tx) {
-		/*
-		 * With the expectation that the IRQ might be shared in SoC
-		 */
-		ret = request_irq(qinst->irq, ti_msgmgr_queue_rx_interrupt,
-				  IRQF_SHARED, qinst->name, chan);
+		/* Allocate usage buffer for rx */
+		qinst->rx_buff = kzalloc(d->max_message_size, GFP_KERNEL);
+		if (!qinst->rx_buff)
+			return -ENOMEM;
+		/* Request IRQ */
+		ret = ti_msgmgr_queue_rx_irq_req(dev, qinst, chan);
 		if (ret) {
-			dev_err(dev, "Unable to get IRQ %d on %s(res=%d)\n",
-				qinst->irq, qinst->name, ret);
+			kfree(qinst->rx_buff);
 			return ret;
 		}
 	}
@@ -346,8 +393,10 @@ static void ti_msgmgr_queue_shutdown(struct mbox_chan *chan)
 {
 	struct ti_queue_inst *qinst = chan->con_priv;
 
-	if (!qinst->is_tx)
+	if (!qinst->is_tx) {
 		free_irq(qinst->irq, chan);
+		kfree(qinst->rx_buff);
+	}
 }
 
 /**
@@ -425,27 +474,6 @@ static int ti_msgmgr_queue_setup(int idx, struct device *dev,
 		 dev_name(dev), qinst->is_tx ? "tx" : "rx", qinst->queue_id,
 		 qinst->proxy_id);
 
-	if (!qinst->is_tx) {
-		char of_rx_irq_name[7];
-
-		snprintf(of_rx_irq_name, sizeof(of_rx_irq_name),
-			 "rx_%03d", qinst->queue_id);
-
-		qinst->irq = of_irq_get_byname(np, of_rx_irq_name);
-		if (qinst->irq < 0) {
-			dev_crit(dev,
-				 "[%d]QID %d PID %d:No IRQ[%s]: %d\n",
-				 idx, qinst->queue_id, qinst->proxy_id,
-				 of_rx_irq_name, qinst->irq);
-			return qinst->irq;
-		}
-		/* Allocate usage buffer for rx */
-		qinst->rx_buff = devm_kzalloc(dev,
-					      d->max_message_size, GFP_KERNEL);
-		if (!qinst->rx_buff)
-			return -ENOMEM;
-	}
-
 	qinst->queue_buff_start = inst->queue_proxy_region +
 	    Q_DATA_OFFSET(qinst->proxy_id, qinst->queue_id, d->data_first_reg);
 	qinst->queue_buff_end = inst->queue_proxy_region +
@@ -454,6 +482,9 @@ static int ti_msgmgr_queue_setup(int idx, struct device *dev,
 	    Q_STATE_OFFSET(qinst->queue_id);
 	qinst->chan = chan;
 
+	/* Setup an error value for IRQ - Lazy allocation */
+	qinst->irq = -EINVAL;
+
 	chan->con_priv = qinst;
 
 	dev_dbg(dev, "[%d] qidx=%d pidx=%d irq=%d q_s=%p q_e = %p\n",
-- 
2.15.1