[RFC PATCH 5/7] remoteproc: virtio: Create platform device for the remoteproc_virtio

[Arnaud Pouliquen]

Define a platform device for the remoteproc virtio to prepare the
management of the remoteproc virtio as a platform device.

The platform device allows to pass rproc_vdev_data platform data to
specify properties that are stored in the rproc_vdev structure.

Such approach will allow to preserve legacy remoteproc virtio device
creation but also to probe the device using device tree mechanism.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxxxxxxx>
---
 drivers/remoteproc/remoteproc_internal.h |  6 +++
 drivers/remoteproc/remoteproc_virtio.c   | 65 ++++++++++++++++++++++++
 include/linux/remoteproc.h               |  2 +
 3 files changed, 73 insertions(+)

diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
index 4ce012c353c0..1b963a8912ed 100644
--- a/drivers/remoteproc/remoteproc_internal.h
+++ b/drivers/remoteproc/remoteproc_internal.h
@@ -24,6 +24,12 @@ struct rproc_debug_trace {
 	struct rproc_mem_entry trace_mem;
 };
 
+struct rproc_vdev_data {
+	u32 rsc_offset;
+	unsigned int id;
+	unsigned int index;
+};
+
 /* from remoteproc_core.c */
 void rproc_release(struct kref *kref);
 int rproc_of_parse_firmware(struct device *dev, int index,
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index c9eecd2f9fb2..9b2ab79e4c4c 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -4,6 +4,7 @@
  *
  * Copyright (C) 2011 Texas Instruments, Inc.
  * Copyright (C) 2011 Google, Inc.
+ * Copyright (C) 2021 STMicroelectronics
  *
  * Ohad Ben-Cohen <ohad@xxxxxxxxxx>
  * Brian Swetland <swetland@xxxxxxxxxx>
@@ -13,6 +14,7 @@
 #include <linux/dma-map-ops.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
+#include <linux/of_platform.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/remoteproc.h>
 #include <linux/virtio.h>
@@ -571,3 +573,66 @@ void rproc_vdev_release(struct kref *ref)
 
 	rproc_rvdev_remove_device(rvdev);
 }
+
+static int rproc_virtio_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rproc_vdev_data *vdev_data = dev->platform_data;
+	struct rproc_vdev *rvdev;
+	struct rproc *rproc;
+
+	if (!vdev_data)
+		return -EINVAL;
+
+	rvdev = devm_kzalloc(dev, sizeof(*rvdev), GFP_KERNEL);
+	if (!rvdev)
+		return -ENOMEM;
+
+	rproc = container_of(dev->parent, struct rproc, dev);
+
+	rvdev->rsc_offset = vdev_data->rsc_offset;
+	rvdev->id = vdev_data->id;
+	rvdev->index = vdev_data->index;
+
+	rvdev->pdev = pdev;
+	rvdev->rproc = rproc;
+
+	platform_set_drvdata(pdev, rvdev);
+
+	return rproc_rvdev_add_device(rvdev);
+}
+
+static int rproc_virtio_remove(struct platform_device *pdev)
+{
+	struct rproc_vdev *rvdev = dev_get_drvdata(&pdev->dev);
+	struct rproc *rproc = rvdev->rproc;
+	struct rproc_vring *rvring;
+	int id;
+
+	for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
+		rvring = &rvdev->vring[id];
+		rproc_free_vring(rvring);
+	}
+
+	rproc_remove_subdev(rproc, &rvdev->subdev);
+	rproc_unregister_rvdev(rvdev);
+	dev_dbg(&pdev->dev, "virtio dev %d removed\n",  rvdev->index);
+
+	return 0;
+}
+
+/* Platform driver */
+static const struct of_device_id rproc_virtio_match[] = {
+	{ .compatible = "rproc-virtio", },
+	{},
+};
+
+static struct platform_driver rproc_virtio_driver = {
+	.probe		= rproc_virtio_probe,
+	.remove		= rproc_virtio_remove,
+	.driver		= {
+		.name	= "rproc-virtio",
+		.of_match_table	= rproc_virtio_match,
+	},
+};
+builtin_platform_driver(rproc_virtio_driver);
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index e0600e1e5c17..542a3d4664f2 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -616,6 +616,7 @@ struct rproc_vring {
  * struct rproc_vdev - remoteproc state for a supported virtio device
  * @refcount: reference counter for the vdev and vring allocations
  * @subdev: handle for registering the vdev as a rproc subdevice
+ * @pdev: remoteproc virtio platform device
  * @dev: device struct used for reference count semantics
  * @id: virtio device id (as in virtio_ids.h)
  * @node: list node
@@ -628,6 +629,7 @@ struct rproc_vdev {
 	struct kref refcount;
 
 	struct rproc_subdev subdev;
+	struct platform_device *pdev;
 	struct device dev;
 
 	unsigned int id;
-- 
2.17.1