soc: qcom: smd: Represent smd edges as devices

By representing each edge as its own device the channels are no longer
tied to being parented by the same smd device and as such an edge can
live as children of e.g. remoteproc instances.

Signed-off-by: Bjorn Andersson <[e-mail]>
Signed-off-by: Andy Gross <[e-mail]>

drivers/soc/qcom/smd.c

···
 
 /**
  * struct qcom_smd_edge - representing a remote processor
- * @smd:		handle to qcom_smd
+ * @dev:		device for this edge
  * @of_node:		of_node handle for information related to this edge
  * @edge_id:		identifier of this edge
  * @remote_pid:		identifier of remote processor
···
  * @state_work:		work item for edge state changes
  */
 struct qcom_smd_edge {
-	struct qcom_smd *smd;
+	struct device dev;
+
 	struct device_node *of_node;
 	unsigned edge_id;
 	unsigned remote_pid;
···
 	struct work_struct scan_work;
 	struct work_struct state_work;
 };
+
+#define to_smd_edge(d) container_of(d, struct qcom_smd_edge, dev)
 
 /*
  * SMD channel states.
···
 	void *drvdata;
 
 	struct list_head list;
-};
-
-/**
- * struct qcom_smd - smd struct
- * @dev:	device struct
- * @num_edges:	number of entries in @edges
- * @edges:	array of edges to be handled
- */
-struct qcom_smd {
-	struct device *dev;
-
-	unsigned num_edges;
-	struct qcom_smd_edge edges[0];
 };
 
 /*
···
 	if (channel->state == state)
 		return;
 
-	dev_dbg(edge->smd->dev, "set_state(%s, %d)\n", channel->name, state);
+	dev_dbg(&edge->dev, "set_state(%s, %d)\n", channel->name, state);
 
 	SET_TX_CHANNEL_FLAG(channel, fDSR, is_open);
 	SET_TX_CHANNEL_FLAG(channel, fCTS, is_open);
···
 	struct qcom_smd_device *qsdev;
 	struct qcom_smd_edge *edge = channel->edge;
 	struct device_node *node;
-	struct qcom_smd *smd = edge->smd;
 	int ret;
 
 	if (channel->qsdev)
 		return -EEXIST;
 
-	dev_dbg(smd->dev, "registering '%s'\n", channel->name);
+	dev_dbg(&edge->dev, "registering '%s'\n", channel->name);
 
 	qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
 	if (!qsdev)
···
 		     edge->of_node->name,
 		     node ? node->name : channel->name);
 
-	qsdev->dev.parent = smd->dev;
+	qsdev->dev.parent = &edge->dev;
 	qsdev->dev.bus = &qcom_smd_bus;
 	qsdev->dev.release = qcom_smd_release_device;
 	qsdev->dev.of_node = node;
···
 
 	ret = device_register(&qsdev->dev);
 	if (ret) {
-		dev_err(smd->dev, "device_register failed: %d\n", ret);
+		dev_err(&edge->dev, "device_register failed: %d\n", ret);
 		put_device(&qsdev->dev);
 	}
 
···
 							char *name)
 {
 	struct qcom_smd_channel *channel;
-	struct qcom_smd *smd = edge->smd;
 	size_t fifo_size;
 	size_t info_size;
 	void *fifo_base;
 	void *info;
 	int ret;
 
-	channel = devm_kzalloc(smd->dev, sizeof(*channel), GFP_KERNEL);
+	channel = devm_kzalloc(&edge->dev, sizeof(*channel), GFP_KERNEL);
 	if (!channel)
 		return ERR_PTR(-ENOMEM);
 
 	channel->edge = edge;
-	channel->name = devm_kstrdup(smd->dev, name, GFP_KERNEL);
+	channel->name = devm_kstrdup(&edge->dev, name, GFP_KERNEL);
 	if (!channel->name)
 		return ERR_PTR(-ENOMEM);
 
···
 	} else if (info_size == 2 * sizeof(struct smd_channel_info)) {
 		channel->info = info;
 	} else {
-		dev_err(smd->dev,
+		dev_err(&edge->dev,
 			"channel info of size %zu not supported\n", info_size);
 		ret = -EINVAL;
 		goto free_name_and_channel;
···
 	/* The channel consist of a rx and tx fifo of equal size */
 	fifo_size /= 2;
 
-	dev_dbg(smd->dev, "new channel '%s' info-size: %zu fifo-size: %zu\n",
+	dev_dbg(&edge->dev, "new channel '%s' info-size: %zu fifo-size: %zu\n",
 			  name, info_size, fifo_size);
 
 	channel->tx_fifo = fifo_base;
···
 	return channel;
 
 free_name_and_channel:
-	devm_kfree(smd->dev, channel->name);
-	devm_kfree(smd->dev, channel);
+	devm_kfree(&edge->dev, channel->name);
+	devm_kfree(&edge->dev, channel);
 
 	return ERR_PTR(ret);
 }
···
 	struct qcom_smd_alloc_entry *alloc_tbl;
 	struct qcom_smd_alloc_entry *entry;
 	struct qcom_smd_channel *channel;
-	struct qcom_smd *smd = edge->smd;
 	unsigned long flags;
 	unsigned fifo_id;
 	unsigned info_id;
···
 			list_add(&channel->list, &edge->channels);
 			spin_unlock_irqrestore(&edge->channels_lock, flags);
 
-			dev_dbg(smd->dev, "new channel found: '%s'\n", channel->name);
+			dev_dbg(&edge->dev, "new channel found: '%s'\n", channel->name);
 			set_bit(i, edge->allocated[tbl]);
 
 			wake_up_interruptible(&edge->new_channel_event);
···
 	return 0;
 }
 
-static int qcom_smd_probe(struct platform_device *pdev)
+/*
+ * Release function for an edge.
+ * Reset the state of each associated channel and free the edge context.
+ */
+static void qcom_smd_edge_release(struct device *dev)
+{
+	struct qcom_smd_channel *channel;
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	list_for_each_entry(channel, &edge->channels, list) {
+		SET_RX_CHANNEL_INFO(channel, state, SMD_CHANNEL_CLOSED);
+		SET_RX_CHANNEL_INFO(channel, head, 0);
+		SET_RX_CHANNEL_INFO(channel, tail, 0);
+	}
+
+	kfree(edge);
+}
+
+/**
+ * qcom_smd_register_edge() - register an edge based on an device_node
+ * @parent:	parent device for the edge
+ * @node:	device_node describing the edge
+ *
+ * Returns an edge reference, or negative ERR_PTR() on failure.
+ */
+struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
+					     struct device_node *node)
 {
 	struct qcom_smd_edge *edge;
-	struct device_node *node;
-	struct qcom_smd *smd;
-	size_t array_size;
-	int num_edges;
 	int ret;
-	int i = 0;
+
+	edge = kzalloc(sizeof(*edge), GFP_KERNEL);
+	if (!edge)
+		return ERR_PTR(-ENOMEM);
+
+	init_waitqueue_head(&edge->new_channel_event);
+
+	edge->dev.parent = parent;
+	edge->dev.release = qcom_smd_edge_release;
+	dev_set_name(&edge->dev, "%s:%s", dev_name(parent), node->name);
+	ret = device_register(&edge->dev);
+	if (ret) {
+		pr_err("failed to register smd edge\n");
+		return ERR_PTR(ret);
+	}
+
+	ret = qcom_smd_parse_edge(&edge->dev, node, edge);
+	if (ret) {
+		dev_err(&edge->dev, "failed to parse smd edge\n");
+		goto unregister_dev;
+	}
+
+	schedule_work(&edge->scan_work);
+
+	return edge;
+
+unregister_dev:
+	put_device(&edge->dev);
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL(qcom_smd_register_edge);
+
+static int qcom_smd_remove_device(struct device *dev, void *data)
+{
+	device_unregister(dev);
+	of_node_put(dev->of_node);
+	put_device(dev);
+
+	return 0;
+}
+
+/**
+ * qcom_smd_unregister_edge() - release an edge and its children
+ * @edge:	edge reference acquired from qcom_smd_register_edge
+ */
+int qcom_smd_unregister_edge(struct qcom_smd_edge *edge)
+{
+	int ret;
+
+	disable_irq(edge->irq);
+	cancel_work_sync(&edge->scan_work);
+	cancel_work_sync(&edge->state_work);
+
+	ret = device_for_each_child(&edge->dev, NULL, qcom_smd_remove_device);
+	if (ret)
+		dev_warn(&edge->dev, "can't remove smd device: %d\n", ret);
+
+	device_unregister(&edge->dev);
+
+	return 0;
+}
+EXPORT_SYMBOL(qcom_smd_unregister_edge);
+
+static int qcom_smd_probe(struct platform_device *pdev)
+{
+	struct device_node *node;
 	void *p;
 
 	/* Wait for smem */
···
 	if (PTR_ERR(p) == -EPROBE_DEFER)
 		return PTR_ERR(p);
 
-	num_edges = of_get_available_child_count(pdev->dev.of_node);
-	array_size = sizeof(*smd) + num_edges * sizeof(struct qcom_smd_edge);
-	smd = devm_kzalloc(&pdev->dev, array_size, GFP_KERNEL);
-	if (!smd)
-		return -ENOMEM;
-	smd->dev = &pdev->dev;
-
-	smd->num_edges = num_edges;
-	for_each_available_child_of_node(pdev->dev.of_node, node) {
-		edge = &smd->edges[i++];
-		edge->smd = smd;
-		init_waitqueue_head(&edge->new_channel_event);
-
-		ret = qcom_smd_parse_edge(&pdev->dev, node, edge);
-		if (ret)
-			continue;
-
-		schedule_work(&edge->scan_work);
-	}
-
-	platform_set_drvdata(pdev, smd);
+	for_each_available_child_of_node(pdev->dev.of_node, node)
+		qcom_smd_register_edge(&pdev->dev, node);
 
 	return 0;
+}
+
+static int qcom_smd_remove_edge(struct device *dev, void *data)
+{
+	struct qcom_smd_edge *edge = to_smd_edge(dev);
+
+	return qcom_smd_unregister_edge(edge);
 }
 
 /*
···
  */
 static int qcom_smd_remove(struct platform_device *pdev)
 {
-	struct qcom_smd_channel *channel;
-	struct qcom_smd_edge *edge;
-	struct qcom_smd *smd = platform_get_drvdata(pdev);
-	int i;
+	int ret;
 
-	for (i = 0; i < smd->num_edges; i++) {
-		edge = &smd->edges[i];
+	ret = device_for_each_child(&pdev->dev, NULL, qcom_smd_remove_edge);
+	if (ret)
+		dev_warn(&pdev->dev, "can't remove smd device: %d\n", ret);
 
-		disable_irq(edge->irq);
-		cancel_work_sync(&edge->scan_work);
-		cancel_work_sync(&edge->state_work);
-
-		/* No need to lock here, because the writer is gone */
-		list_for_each_entry(channel, &edge->channels, list) {
-			if (!channel->qsdev)
-				continue;
-
-			qcom_smd_destroy_device(channel);
-		}
-	}
-
-	return 0;
+	return ret;
 }
 
 static const struct of_device_id qcom_smd_of_match[] = {

include/linux/soc/qcom/smd.h

···
 int qcom_smd_send(struct qcom_smd_channel *channel, const void *data, int len);
 
 
+struct qcom_smd_edge *qcom_smd_register_edge(struct device *parent,
+					     struct device_node *node);
+int qcom_smd_unregister_edge(struct qcom_smd_edge *edge);
+
 #else
 
 static inline int qcom_smd_driver_register(struct qcom_smd_driver *drv)
···
 
 static inline int qcom_smd_send(struct qcom_smd_channel *channel,
 				const void *data, int len)
+{
+	/* This shouldn't be possible */
+	WARN_ON(1);
+	return -ENXIO;
+}
+
+static inline struct qcom_smd_edge *
+qcom_smd_register_edge(struct device *parent,
+		       struct device_node *node)
+{
+	return ERR_PTR(-ENXIO);
+}
+
+static inline int qcom_smd_unregister_edge(struct qcom_smd_edge *edge)
 {
 	/* This shouldn't be possible */
 	WARN_ON(1);