remoteproc: core: Add capability to populate rproc virtio subnode dev…

…ices

Add the capability to add rproc virtio sub nodes in device tree.
Devices declared as rproc sub node will be probed
before the remote firmware boot sequence.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

drivers/remoteproc/remoteproc_core.c

@@ -28,6 +28,7 @@
 #include <linux/string.h>
 #include <linux/debugfs.h>
 #include <linux/rculist.h>
+#include <linux/of_platform.h>
 #include <linux/remoteproc.h>
 #include <linux/iommu.h>
 #include <linux/idr.h>
@@ -1856,6 +1857,31 @@ static void rproc_crash_handler_work(struct work_struct *work)
 	pm_relax(rproc->dev.parent);
 }
 
+static const struct of_device_id rproc_child_match_table[] = {
+	{ .compatible = "rproc-virtio", },
+	{ }
+};
+
+static int rproc_platform_populate(struct rproc *rproc)
+{
+	struct device *dev = rproc->dev.parent;
+	int ret;
+
+	ret = of_platform_populate(dev->of_node, rproc_child_match_table, NULL, dev);
+	if (ret < 0) {
+		dev_err(dev, "failed to populate child devices (%d)\n", ret);
+
+		goto depopulate;
+	}
+
+	return 0;
+
+depopulate:
+	of_platform_depopulate(dev);
+
+	return ret;
+}
+
 /**
  * rproc_boot() - boot a remote processor
  * @rproc: handle of a remote processor
@@ -2265,6 +2291,11 @@ int rproc_add(struct rproc *rproc)
 	list_add_rcu(&rproc->node, &rproc_list);
 	mutex_unlock(&rproc_list_mutex);
 
+	/* probe remoteproc device resource suppliers */
+	ret = rproc_platform_populate(rproc);
+	if (ret)
+		return ret;
+
 	return 0;
 
 rproc_remove_dev:
@@ -2537,6 +2568,8 @@ int rproc_del(struct rproc *rproc)
 	/* Ensure that no readers of rproc_list are still active */
 	synchronize_rcu();
 
+	of_platform_depopulate(rproc->dev.parent);
+
 	device_del(&rproc->dev);
 	rproc_char_device_remove(rproc);