GLINK intent preallocation support

Intents are used to specify when a channel can receive data from a remoteproc. Add support for channels to customize the size and amount of prequeued intents.

An audio channel might expect to receive 3 packets of size 4k in rapid succession. This change allows the channel to prepare for this data instead of allocating on demand.

Chris Lew (3):
dt-bindings: soc: qcom: Support GLINK intents
rpmsg: glink: Add support to preallocate intents
rpmsg: glink: Use best fit intent during tx

 .../devicetree/bindings/soc/qcom/qcom,glink.txt    | 10 +++++
 drivers/rpmsg/qcom_glink_native.c                  | 48 +++++++++++++++++-----
 2 files changed, 47 insertions(+), 11 deletions(-)

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Virtual GLINK channels may know what throughput to expect from a remoteproc. An intent advertises to the remoteproc this channel is ready to receive data. Allow a channel to define the size and amount of intents to be prequeued.

---

Changes since v1:
- Change intents property to qcom,intents and update example
- Change second sentence in definition to better describe usage

 Documentation/devicetree/bindings/soc/qcom/qcom,glink.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

index b277eca861f7..9663cab52246 100644
@@ -39,6 +39,14 @@ of these nodes are defined by the individual bindings for the specific function
 	Definition: a list of channels tied to this function, used for matching
 		    the function to a set of virtual channels
 
+- qcom,intents:
+	Usage: optional
+	Value type: <prop-encoded-array>
+	Definition: a list of size,amount pairs describing what intents should
+		    be preallocated for this virtual channel. This can be used
+		    to tweak the default intents available for the channel to
+		    meet expectations of the remote.
+
 = EXAMPLE
 The following example represents the GLINK RPM node on a MSM8996 device, with
 the function for the "rpm_request" channel defined, which is used for

@@ -69,6 +77,8 @@ regualtors and root clocks.
 			compatible = "qcom,rpm-msm8996";
 			qcom,glink-channels = "rpm_requests";
 
+			qcom,intents = <0x400 5
+					0x800 1>;
 			...
 		};
 	};

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a Linux Foundation Collaborative Project

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The base intents prequeued during channel creation may not satisfy a channel's throughput requirement. Add support for intents dt-binding to allow channels to specify the size and amount of intents to prequeue during endpoint announcement.

---

Changes since v1:
- Change intents property string to qcom,intents
- Use np local variable to fit of_find_property call on one line

 drivers/rpmsg/qcom_glink_native.c | 37 +++++++++++++++++++++++++++++--------
 1 file changed, 29 insertions(+), 8 deletions(-)

index 5a5e927ea50f..7155adad6ab6 100644
@@ -1143,19 +1143,40 @@ static struct rpmsg_endpoint *qcom_glink_create_ept(struct rpmsg_device *rpdev,
 static int qcom_glink_announce_create(struct rpmsg_device *rpdev)
 {
 	struct glink_channel *channel = to_glink_channel(rpdev->ept);
-	struct glink_core_rx_intent *intent;
+	struct device_node *np = rpdev->dev.of_node;
 	struct qcom_glink *glink = channel->glink;
-	int num_intents = glink->intentless ? 0 : 5;
+	struct glink_core_rx_intent *intent;
+	const struct property *prop = NULL;
+	int num_groups = 1;
+	int num_intents;
+	int size;
+	__be32 base[2];
+	int *val = base;
+
+	if (np)
+		prop = of_find_property(np, "qcom,intents", NULL);
+
+	if (prop && !glink->intentless) {
+		val = prop->value;
+		num_groups = prop->length / sizeof(u32) / 2;
+	} else {
+		base[0] = cpu_to_be32(SZ_1K);
+		base[1] = cpu_to_be32(glink->intentless ? 0 : 5);
+	}
 
 	/* Channel is now open, advertise base set of intents */
-	while (num_intents--) {
-		intent = qcom_glink_alloc_intent(glink, channel, SZ_1K, true);
-		if (!intent)
-			break;
+	while (num_groups--) {
+		size = be32_to_cpup(val++);
+		num_intents = be32_to_cpup(val++);
+		while(num_intents--) {
+			intent = qcom_glink_alloc_intent(glink, channel, size,
+							 true);
+			if (!intent)
+				break;
 
-		qcom_glink_advertise_intent(glink, channel, intent);
+			qcom_glink_advertise_intent(glink, channel, intent);
+		}
 	}
-
 	return 0;
 }
 

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Intents can vary in size, try to find the best fitting remote intent instead of first fit when sending a message to the remote proc.

---
 drivers/rpmsg/qcom_glink_native.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

index 7155adad6ab6..0ba1ffe2698f 100644
@@ -1252,11 +1252,16 @@ static int __qcom_glink_send(struct glink_channel *channel,
 			spin_lock_irqsave(&channel->intent_lock, flags);
 			idr_for_each_entry(&channel->riids, tmp, iid) {
 				if (tmp->size >= len && !tmp->in_use) {
-					tmp->in_use = true;
-					intent = tmp;
-					break;
+					if (!intent)
+						intent = tmp;
+					else if (intent->size > tmp->size)
+						intent = tmp;
+					if (intent->size == len)
+						break;
 				}
 			}
+			if (intent)
+				intent->in_use = true;
 			spin_unlock_irqrestore(&channel->intent_lock, flags);
 
 			/* We found an available intent */

The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

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Thanks, tested and applied with some minor modifications to patch 2.

Regards,
Bjorn