[PATCH RFC v2 07/11] remoteproc: assign fwnode during vdev registration

[Francesco Valla <francesco@valla.it>]

The virtio subsystem already supports a fwnode describing a vdev; search
for a specific node during vdev registration and supply it to the
rproc-virtio platform device that is being registered.

A memory-region specified inside that node is also used for the virtio
device if a carveout was not supplied for it through the parent device's
node.

Signed-off-by: Francesco Valla <francesco@valla.it>
---
 drivers/remoteproc/remoteproc_core.c   | 48 +++++++++++++++++++++++++++++++---
 drivers/remoteproc/remoteproc_virtio.c | 41 +++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 4 deletions(-)

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index c946ecd980a5..e833853ae7f6 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -440,6 +440,33 @@ void rproc_remove_rvdev(struct rproc_vdev *rvdev)
 	if (rvdev)
 		list_del(&rvdev->node);
 }
+
+static struct fwnode_handle *rproc_get_vdev_fwnode(struct device *dev, u32 idx)
+{
+	struct fwnode_handle *group, *child;
+	u32 reg;
+	int ret;
+
+	group = device_get_named_child_node(dev, "virtio");
+	if (!fwnode_device_is_available(group)) {
+		fwnode_handle_put(group);
+		return NULL;
+	}
+
+	fwnode_for_each_available_child_node(group, child) {
+		ret = fwnode_property_read_u32(child, "reg", &reg);
+		if (ret)
+			continue;
+
+		if (idx == reg)
+			break;
+	}
+
+	fwnode_handle_put(group);
+
+	return child;
+}
+
 /**
  * rproc_handle_vdev() - handle a vdev fw resource
  * @rproc: the remote processor
@@ -475,7 +502,16 @@ static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
 	struct device *dev = &rproc->dev;
 	size_t rsc_size;
 	struct rproc_vdev_data rvdev_data;
+	struct platform_device_info pdev_info = {
+		.parent = dev,
+		.name = "rproc-virtio",
+		.id = PLATFORM_DEVID_AUTO,
+		.data = &rvdev_data,
+		.size_data = sizeof(rvdev_data),
+	};
 	struct platform_device *pdev;
+	struct fwnode_handle *fwnode;
+	int ret = 0;
 
 	/* make sure resource isn't truncated */
 	rsc_size = struct_size(rsc, vring, rsc->num_of_vrings);
@@ -498,20 +534,24 @@ static int rproc_handle_vdev(struct rproc *rproc, void *ptr,
 	rvdev_data.rsc_offset = offset;
 	rvdev_data.rsc = rsc;
 
+	fwnode = rproc_get_vdev_fwnode(dev->parent, rvdev_data.index);
+	pdev_info.fwnode = fwnode;
+
 	/*
 	 * When there is more than one remote processor, rproc->nb_vdev number is
 	 * same for each separate instances of "rproc". If rvdev_data.index is used
 	 * as device id, then we get duplication in sysfs, so need to use
 	 * PLATFORM_DEVID_AUTO to auto select device id.
 	 */
-	pdev = platform_device_register_data(dev, "rproc-virtio", PLATFORM_DEVID_AUTO, &rvdev_data,
-					     sizeof(rvdev_data));
+	pdev = platform_device_register_full(&pdev_info);
 	if (IS_ERR(pdev)) {
 		dev_err(dev, "failed to create rproc-virtio device\n");
-		return PTR_ERR(pdev);
+		ret = PTR_ERR(pdev);
 	}
 
-	return 0;
+	fwnode_handle_put(fwnode);
+
+	return ret;
 }
 
 /**
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index 1496659ddff9..950d65480be5 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -13,10 +13,12 @@
 #include <linux/dma-map-ops.h>
 #include <linux/dma-mapping.h>
 #include <linux/export.h>
+#include <linux/of.h>
 #include <linux/of_reserved_mem.h>
 #include <linux/platform_device.h>
 #include <linux/remoteproc.h>
 #include <linux/rsc_table.h>
+#include <linux/swiotlb.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_ids.h>
@@ -394,6 +396,23 @@ static void rproc_virtio_dev_release(struct device *dev)
 	put_device(&rvdev->pdev->dev);
 }
 
+/*
+ * Attach the memory region declared inside the vdev's own devicetree node.
+ *
+ * A restricted-dma-pool region is attached by of_dma_configure() when the
+ * platform device is probed, but it is released together with the virtio
+ * device (see rproc_virtio_dev_release()); attach it again if needed, e.g.
+ * when the remote processor is restarted during a crash recovery.
+ * Any other kind of region (e.g., shared-dma-pool) is attached only here.
+ */
+static int rproc_virtio_init_vdev_mem(struct device *dev)
+{
+	if (is_swiotlb_for_alloc(dev))
+		return 0;
+
+	return of_reserved_mem_device_init_by_idx(dev, dev->of_node, 0);
+}
+
 /**
  * rproc_add_virtio_dev() - register an rproc-induced virtio device
  * @rvdev: the remote vdev
@@ -410,6 +429,7 @@ static int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 	struct device *dev = &rvdev->pdev->dev;
 	struct virtio_device *vdev;
 	struct rproc_mem_entry *mem;
+	bool has_mem_region;
 	int ret;
 
 	if (rproc->ops->kick == NULL) {
@@ -417,11 +437,24 @@ static int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 		return -EINVAL;
 	}
 
+	has_mem_region = of_property_present(dev->of_node, "memory-region");
+
 	/* Try to find dedicated vdev buffer carveout */
 	mem = rproc_find_carveout_by_name(rproc, "vdev%dbuffer", rvdev->index);
 	if (mem) {
 		phys_addr_t pa;
 
+		if (has_mem_region) {
+			/*
+			 * The carveout takes precedence: drop the region that
+			 * of_dma_configure() might have attached at probe time.
+			 */
+			dev_warn(dev,
+				 "vdev%dbuffer carveout found, ignoring memory-region\n",
+				 rvdev->index);
+			of_reserved_mem_device_release(dev);
+		}
+
 		if (mem->of_resm_idx != -1) {
 			struct device_node *np = rproc->dev.parent->of_node;
 
@@ -451,6 +484,14 @@ static int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 				return ret;
 			}
 		}
+	} else if (has_mem_region) {
+		/* Use the memory region declared in the vdev's own node */
+		ret = rproc_virtio_init_vdev_mem(dev);
+		if (ret) {
+			dev_err(dev, "Can't associate vdev memory-region: %d\n",
+				ret);
+			return ret;
+		}
 	} else {
 		struct device_node *np = rproc->dev.parent->of_node;
 

-- 
2.56.0