1 files changed, 441 insertions, 0 deletions
diff --git a/drivers/fpga/fpga-bridge.c b/drivers/fpga/fpga-bridge.c
new file mode 100644
index 000000000..a024be2b8
--- /dev/null
+++ b/drivers/fpga/fpga-bridge.c
@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * FPGA Bridge Framework Driver
+ *
+ *  Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
+ *  Copyright (C) 2017 Intel Corporation
+ */
+#include <linux/fpga/fpga-bridge.h>
+#include <linux/idr.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+static DEFINE_IDA(fpga_bridge_ida);
+static const struct class fpga_bridge_class;
+
+/* Lock for adding/removing bridges to linked lists*/
+static DEFINE_SPINLOCK(bridge_list_lock);
+
+/**
+ * fpga_bridge_enable - Enable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */
+int fpga_bridge_enable(struct fpga_bridge *bridge)
+{
+	dev_dbg(&bridge->dev, "enable\n");
+
+	if (bridge->br_ops && bridge->br_ops->enable_set)
+		return bridge->br_ops->enable_set(bridge, 1);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_enable);
+
+/**
+ * fpga_bridge_disable - Disable transactions on the bridge
+ *
+ * @bridge: FPGA bridge
+ *
+ * Return: 0 for success, error code otherwise.
+ */
+int fpga_bridge_disable(struct fpga_bridge *bridge)
+{
+	dev_dbg(&bridge->dev, "disable\n");
+
+	if (bridge->br_ops && bridge->br_ops->enable_set)
+		return bridge->br_ops->enable_set(bridge, 0);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_disable);
+
+static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
+					     struct fpga_image_info *info)
+{
+	struct fpga_bridge *bridge;
+	int ret = -ENODEV;
+
+	bridge = to_fpga_bridge(dev);
+
+	bridge->info = info;
+
+	if (!mutex_trylock(&bridge->mutex)) {
+		ret = -EBUSY;
+		goto err_dev;
+	}
+
+	if (!try_module_get(dev->parent->driver->owner))
+		goto err_ll_mod;
+
+	dev_dbg(&bridge->dev, "get\n");
+
+	return bridge;
+
+err_ll_mod:
+	mutex_unlock(&bridge->mutex);
+err_dev:
+	put_device(dev);
+	return ERR_PTR(ret);
+}
+
+/**
+ * of_fpga_bridge_get - get an exclusive reference to an fpga bridge
+ *
+ * @np: node pointer of an FPGA bridge.
+ * @info: fpga image specific information.
+ *
+ * Return:
+ * * fpga_bridge struct pointer if successful.
+ * * -EBUSY if someone already has a reference to the bridge.
+ * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount.
+ */
+struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
+				       struct fpga_image_info *info)
+{
+	struct device *dev;
+
+	dev = class_find_device_by_of_node(&fpga_bridge_class, np);
+	if (!dev)
+		return ERR_PTR(-ENODEV);
+
+	return __fpga_bridge_get(dev, info);
+}
+EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
+
+static int fpga_bridge_dev_match(struct device *dev, const void *data)
+{
+	return dev->parent == data;
+}
+
+/**
+ * fpga_bridge_get - get an exclusive reference to an fpga bridge
+ * @dev:	parent device that fpga bridge was registered with
+ * @info:	fpga image specific information
+ *
+ * Given a device, get an exclusive reference to an fpga bridge.
+ *
+ * Return: fpga bridge struct or IS_ERR() condition containing error code.
+ */
+struct fpga_bridge *fpga_bridge_get(struct device *dev,
+				    struct fpga_image_info *info)
+{
+	struct device *bridge_dev;
+
+	bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev,
+				       fpga_bridge_dev_match);
+	if (!bridge_dev)
+		return ERR_PTR(-ENODEV);
+
+	return __fpga_bridge_get(bridge_dev, info);
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_get);
+
+/**
+ * fpga_bridge_put - release a reference to a bridge
+ *
+ * @bridge: FPGA bridge
+ */
+void fpga_bridge_put(struct fpga_bridge *bridge)
+{
+	dev_dbg(&bridge->dev, "put\n");
+
+	bridge->info = NULL;
+	module_put(bridge->dev.parent->driver->owner);
+	mutex_unlock(&bridge->mutex);
+	put_device(&bridge->dev);
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_put);
+
+/**
+ * fpga_bridges_enable - enable bridges in a list
+ * @bridge_list: list of FPGA bridges
+ *
+ * Enable each bridge in the list. If list is empty, do nothing.
+ *
+ * Return: 0 for success or empty bridge list or an error code otherwise.
+ */
+int fpga_bridges_enable(struct list_head *bridge_list)
+{
+	struct fpga_bridge *bridge;
+	int ret;
+
+	list_for_each_entry(bridge, bridge_list, node) {
+		ret = fpga_bridge_enable(bridge);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridges_enable);
+
+/**
+ * fpga_bridges_disable - disable bridges in a list
+ *
+ * @bridge_list: list of FPGA bridges
+ *
+ * Disable each bridge in the list. If list is empty, do nothing.
+ *
+ * Return: 0 for success or empty bridge list or an error code otherwise.
+ */
+int fpga_bridges_disable(struct list_head *bridge_list)
+{
+	struct fpga_bridge *bridge;
+	int ret;
+
+	list_for_each_entry(bridge, bridge_list, node) {
+		ret = fpga_bridge_disable(bridge);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridges_disable);
+
+/**
+ * fpga_bridges_put - put bridges
+ *
+ * @bridge_list: list of FPGA bridges
+ *
+ * For each bridge in the list, put the bridge and remove it from the list.
+ * If list is empty, do nothing.
+ */
+void fpga_bridges_put(struct list_head *bridge_list)
+{
+	struct fpga_bridge *bridge, *next;
+	unsigned long flags;
+
+	list_for_each_entry_safe(bridge, next, bridge_list, node) {
+		fpga_bridge_put(bridge);
+
+		spin_lock_irqsave(&bridge_list_lock, flags);
+		list_del(&bridge->node);
+		spin_unlock_irqrestore(&bridge_list_lock, flags);
+	}
+}
+EXPORT_SYMBOL_GPL(fpga_bridges_put);
+
+/**
+ * of_fpga_bridge_get_to_list - get a bridge, add it to a list
+ *
+ * @np: node pointer of an FPGA bridge
+ * @info: fpga image specific information
+ * @bridge_list: list of FPGA bridges
+ *
+ * Get an exclusive reference to the bridge and it to the list.
+ *
+ * Return: 0 for success, error code from of_fpga_bridge_get() otherwise.
+ */
+int of_fpga_bridge_get_to_list(struct device_node *np,
+			       struct fpga_image_info *info,
+			       struct list_head *bridge_list)
+{
+	struct fpga_bridge *bridge;
+	unsigned long flags;
+
+	bridge = of_fpga_bridge_get(np, info);
+	if (IS_ERR(bridge))
+		return PTR_ERR(bridge);
+
+	spin_lock_irqsave(&bridge_list_lock, flags);
+	list_add(&bridge->node, bridge_list);
+	spin_unlock_irqrestore(&bridge_list_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
+
+/**
+ * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
+ *
+ * @dev: FPGA bridge device
+ * @info: fpga image specific information
+ * @bridge_list: list of FPGA bridges
+ *
+ * Get an exclusive reference to the bridge and it to the list.
+ *
+ * Return: 0 for success, error code from fpga_bridge_get() otherwise.
+ */
+int fpga_bridge_get_to_list(struct device *dev,
+			    struct fpga_image_info *info,
+			    struct list_head *bridge_list)
+{
+	struct fpga_bridge *bridge;
+	unsigned long flags;
+
+	bridge = fpga_bridge_get(dev, info);
+	if (IS_ERR(bridge))
+		return PTR_ERR(bridge);
+
+	spin_lock_irqsave(&bridge_list_lock, flags);
+	list_add(&bridge->node, bridge_list);
+	spin_unlock_irqrestore(&bridge_list_lock, flags);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
+
+static ssize_t name_show(struct device *dev,
+			 struct device_attribute *attr, char *buf)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+
+	return sprintf(buf, "%s\n", bridge->name);
+}
+
+static ssize_t state_show(struct device *dev,
+			  struct device_attribute *attr, char *buf)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+	int state = 1;
+
+	if (bridge->br_ops && bridge->br_ops->enable_show) {
+		state = bridge->br_ops->enable_show(bridge);
+		if (state < 0)
+			return state;
+	}
+
+	return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled");
+}
+
+static DEVICE_ATTR_RO(name);
+static DEVICE_ATTR_RO(state);
+
+static struct attribute *fpga_bridge_attrs[] = {
+	&dev_attr_name.attr,
+	&dev_attr_state.attr,
+	NULL,
+};
+ATTRIBUTE_GROUPS(fpga_bridge);
+
+/**
+ * fpga_bridge_register - create and register an FPGA Bridge device
+ * @parent:	FPGA bridge device from pdev
+ * @name:	FPGA bridge name
+ * @br_ops:	pointer to structure of fpga bridge ops
+ * @priv:	FPGA bridge private data
+ *
+ * Return: struct fpga_bridge pointer or ERR_PTR()
+ */
+struct fpga_bridge *
+fpga_bridge_register(struct device *parent, const char *name,
+		     const struct fpga_bridge_ops *br_ops,
+		     void *priv)
+{
+	struct fpga_bridge *bridge;
+	int id, ret;
+
+	if (!br_ops) {
+		dev_err(parent, "Attempt to register without fpga_bridge_ops\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	if (!name || !strlen(name)) {
+		dev_err(parent, "Attempt to register with no name!\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
+	if (!bridge)
+		return ERR_PTR(-ENOMEM);
+
+	id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL);
+	if (id < 0) {
+		ret = id;
+		goto error_kfree;
+	}
+
+	mutex_init(&bridge->mutex);
+	INIT_LIST_HEAD(&bridge->node);
+
+	bridge->name = name;
+	bridge->br_ops = br_ops;
+	bridge->priv = priv;
+
+	bridge->dev.groups = br_ops->groups;
+	bridge->dev.class = &fpga_bridge_class;
+	bridge->dev.parent = parent;
+	bridge->dev.of_node = parent->of_node;
+	bridge->dev.id = id;
+
+	ret = dev_set_name(&bridge->dev, "br%d", id);
+	if (ret)
+		goto error_device;
+
+	ret = device_register(&bridge->dev);
+	if (ret) {
+		put_device(&bridge->dev);
+		return ERR_PTR(ret);
+	}
+
+	of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev);
+
+	return bridge;
+
+error_device:
+	ida_free(&fpga_bridge_ida, id);
+error_kfree:
+	kfree(bridge);
+
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_register);
+
+/**
+ * fpga_bridge_unregister - unregister an FPGA bridge
+ *
+ * @bridge: FPGA bridge struct
+ *
+ * This function is intended for use in an FPGA bridge driver's remove function.
+ */
+void fpga_bridge_unregister(struct fpga_bridge *bridge)
+{
+	/*
+	 * If the low level driver provides a method for putting bridge into
+	 * a desired state upon unregister, do it.
+	 */
+	if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
+		bridge->br_ops->fpga_bridge_remove(bridge);
+
+	device_unregister(&bridge->dev);
+}
+EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
+
+static void fpga_bridge_dev_release(struct device *dev)
+{
+	struct fpga_bridge *bridge = to_fpga_bridge(dev);
+
+	ida_free(&fpga_bridge_ida, bridge->dev.id);
+	kfree(bridge);
+}
+
+static const struct class fpga_bridge_class = {
+	.name = "fpga_bridge",
+	.dev_groups = fpga_bridge_groups,
+	.dev_release = fpga_bridge_dev_release,
+};
+
+static int __init fpga_bridge_dev_init(void)
+{
+	return class_register(&fpga_bridge_class);
+}
+
+static void __exit fpga_bridge_dev_exit(void)
+{
+	class_unregister(&fpga_bridge_class);
+	ida_destroy(&fpga_bridge_ida);
+}
+
+MODULE_DESCRIPTION("FPGA Bridge Driver");
+MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
+MODULE_LICENSE("GPL v2");
+
+subsys_initcall(fpga_bridge_dev_init);
+module_exit(fpga_bridge_dev_exit);