[PATCH V5 0/5] Add chrdev and name query support for GLINK

[PATCH V5 0/5] Add chrdev and name query support for GLINK

[Arun Kumar Neelakantam]

Add support for the GLINK rpmsg transport to register a rpmsg chrdev.
This will create the rpmsg_ctrl nodes for userspace clients to open 
rpmsg epts. The rpmsg chrdev allocation is done by allocating a local
channel which also allocates an ept. We need to add some guards against
edge cases for this chrdev because it will never fully open.

Changes since v5:
- Re-orange the completion_done code

Changes since v4:
- Resending by removing approved patches

Changes since v3:
- Change to device_add_group for rpmsg name attr
- Add patch to unregister the rpmsg device
- Add patch to support compat ioctl for rpmsg char driver

Changes since v2:
- Revert change to make glink attribute table const

Changes since v1:
- Add explanation to dt-bindings commit message
- Add patch complete_all the open_req/ack variables
- Add patch to prevent null pointer dereference in chrdev channel release
- Change chrdev allocation to use glink channel allocation
- Change glink attr struct to const

Arun Kumar Neelakantam (1):
  rpmsg: glink: unregister rpmsg device during endpoint destroy

Chris Lew (4):
  rpmsg: glink: Use complete_all for open states
  rpmsg: Guard against null endpoint ops in destroy
  rpmsg: glink: Add support for rpmsg glink chrdev
  rpmsg: glink: Expose rpmsg name attr for glink

 drivers/rpmsg/qcom_glink_native.c | 79 +++++++++++++++++++++++++++++++++++++--
 drivers/rpmsg/rpmsg_core.c        |  2 +-
 2 files changed, 77 insertions(+), 4 deletions(-)

-- 
2.7.4

[PATCH V6 1/5] rpmsg: glink: Use complete_all for open states

[Arun Kumar Neelakantam]

From: Chris Lew <clew@codeaurora.org>

The open_req and open_ack completion variables are the state variables
to represent a remote channel as open. Use complete_all so there are no
races with waiters and using completion_done.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 1995f5b..ea2f33f 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -970,7 +970,7 @@ static int qcom_glink_rx_open_ack(struct qcom_glink *glink, unsigned int lcid)
 		return -EINVAL;
 	}
 
-	complete(&channel->open_ack);
+	complete_all(&channel->open_ack);
 
 	return 0;
 }
@@ -1178,7 +1178,7 @@ static int qcom_glink_announce_create(struct rpmsg_device *rpdev)
 	__be32 *val = defaults;
 	int size;
 
-	if (glink->intentless)
+	 if (glink->intentless || !completion_done(&channel->open_ack))
 		return 0;
 
 	prop = of_find_property(np, "qcom,intents", NULL);
@@ -1413,7 +1413,7 @@ static int qcom_glink_rx_open(struct qcom_glink *glink, unsigned int rcid,
 	channel->rcid = ret;
 	spin_unlock_irqrestore(&glink->idr_lock, flags);
 
-	complete(&channel->open_req);
+	complete_all(&channel->open_req);
 
 	if (create_device) {
 		rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
-- 
2.7.4

[PATCH V6 2/5] rpmsg: Guard against null endpoint ops in destroy

[Arun Kumar Neelakantam]

From: Chris Lew <clew@codeaurora.org>

In RPMSG GLINK the chrdev device will allocate an ept as part of the
rpdev creation. This device will not register endpoint ops even though
it has an allocated ept. Protect against the case where the device is
being destroyed.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/rpmsg_core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
index e330ec4..d6c3275 100644
--- a/drivers/rpmsg/rpmsg_core.c
+++ b/drivers/rpmsg/rpmsg_core.c
@@ -81,7 +81,7 @@ EXPORT_SYMBOL(rpmsg_create_ept);
  */
 void rpmsg_destroy_ept(struct rpmsg_endpoint *ept)
 {
-	if (ept)
+	if (ept && ept->ops)
 		ept->ops->destroy_ept(ept);
 }
 EXPORT_SYMBOL(rpmsg_destroy_ept);
-- 
2.7.4

[PATCH V6 3/5] rpmsg: glink: Add support for rpmsg glink chrdev

[Arun Kumar Neelakantam]

From: Chris Lew <clew@codeaurora.org>

RPMSG provides a char device interface to userspace. Probe the rpmsg
chrdev channel to enable the rpmsg_ctrl device creation on glink
transports.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index ea2f33f..b85433c 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1574,6 +1574,40 @@ static void qcom_glink_cancel_rx_work(struct qcom_glink *glink)
 		kfree(dcmd);
 }
 
+static void qcom_glink_device_release(struct device *dev)
+{
+	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+	struct glink_channel *channel = to_glink_channel(rpdev->ept);
+
+	/* Release qcom_glink_alloc_channel() reference */
+	kref_put(&channel->refcount, qcom_glink_channel_release);
+	kfree(rpdev);
+}
+
+static int qcom_glink_create_chrdev(struct qcom_glink *glink)
+{
+	struct rpmsg_device *rpdev;
+	struct glink_channel *channel;
+
+	rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
+	if (!rpdev)
+		return -ENOMEM;
+
+	channel = qcom_glink_alloc_channel(glink, "rpmsg_chrdev");
+	if (IS_ERR(channel)) {
+		kfree(rpdev);
+		return PTR_ERR(channel);
+	}
+	channel->rpdev = rpdev;
+
+	rpdev->ept = &channel->ept;
+	rpdev->ops = &glink_device_ops;
+	rpdev->dev.parent = glink->dev;
+	rpdev->dev.release = qcom_glink_device_release;
+
+	return rpmsg_chrdev_register_device(rpdev);
+}
+
 struct qcom_glink *qcom_glink_native_probe(struct device *dev,
 					   unsigned long features,
 					   struct qcom_glink_pipe *rx,
@@ -1633,6 +1667,10 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
 	if (ret)
 		return ERR_PTR(ret);
 
+	ret = qcom_glink_create_chrdev(glink);
+	if (ret)
+		dev_err(glink->dev, "failed to register chrdev\n");
+
 	return glink;
 }
 EXPORT_SYMBOL_GPL(qcom_glink_native_probe);
-- 
2.7.4

[PATCH V6 4/5] rpmsg: glink: Expose rpmsg name attr for glink

[Arun Kumar Neelakantam]

From: Chris Lew <clew@codeaurora.org>

Expose the name field as an attr so clients listening to uevents for
rpmsg can identify the edge the events correspond to.

Signed-off-by: Chris Lew <clew@codeaurora.org>
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index b85433c..2b5368b 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1574,6 +1574,26 @@ static void qcom_glink_cancel_rx_work(struct qcom_glink *glink)
 		kfree(dcmd);
 }
 
+static ssize_t rpmsg_name_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	int ret = 0;
+	const char *name;
+
+	ret = of_property_read_string(dev->of_node, "label", &name);
+	if (ret < 0)
+		name = dev->of_node->name;
+
+	return snprintf(buf, RPMSG_NAME_SIZE, "%s\n", name);
+}
+static DEVICE_ATTR_RO(rpmsg_name);
+
+static struct attribute *qcom_glink_attrs[] = {
+	&dev_attr_rpmsg_name.attr,
+	NULL
+};
+ATTRIBUTE_GROUPS(qcom_glink);
+
 static void qcom_glink_device_release(struct device *dev)
 {
 	struct rpmsg_device *rpdev = to_rpmsg_device(dev);
@@ -1638,6 +1658,12 @@ struct qcom_glink *qcom_glink_native_probe(struct device *dev,
 	idr_init(&glink->lcids);
 	idr_init(&glink->rcids);
 
+	glink->dev->groups = qcom_glink_groups;
+
+	ret = device_add_groups(dev, qcom_glink_groups);
+	if (ret)
+		dev_err(dev, "failed to add groups\n");
+
 	ret = of_property_read_string(dev->of_node, "label", &glink->name);
 	if (ret < 0)
 		glink->name = dev->of_node->name;
-- 
2.7.4

[PATCH V6 5/5] rpmsg: glink: unregister rpmsg device during endpoint destroy

[Arun Kumar Neelakantam]

Rpmsg device unregister is not happening if channel close is triggered
from local side and causing re-registration of device failures.

Unregister rpmsg device for local close in endpoint destroy path.

Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>
---
 drivers/rpmsg/qcom_glink_native.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index 2b5368b..53b90a1 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -1207,6 +1207,7 @@ static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
 {
 	struct glink_channel *channel = to_glink_channel(ept);
 	struct qcom_glink *glink = channel->glink;
+	struct rpmsg_channel_info chinfo;
 	unsigned long flags;
 
 	spin_lock_irqsave(&channel->recv_lock, flags);
@@ -1214,6 +1215,13 @@ static void qcom_glink_destroy_ept(struct rpmsg_endpoint *ept)
 	spin_unlock_irqrestore(&channel->recv_lock, flags);
 
 	/* Decouple the potential rpdev from the channel */
+	if (channel->rpdev) {
+		strncpy(chinfo.name, channel->name, sizeof(chinfo.name));
+		chinfo.src = RPMSG_ADDR_ANY;
+		chinfo.dst = RPMSG_ADDR_ANY;
+
+		rpmsg_unregister_device(glink->dev, &chinfo);
+	}
 	channel->rpdev = NULL;
 
 	qcom_glink_send_close_req(glink, channel);
@@ -1477,6 +1485,7 @@ static void qcom_glink_rx_close(struct qcom_glink *glink, unsigned int rcid)
 
 		rpmsg_unregister_device(glink->dev, &chinfo);
 	}
+	channel->rpdev = NULL;
 
 	qcom_glink_send_close_ack(glink, channel->rcid);
 
-- 
2.7.4