text: /*
   *    Copyright (C) 2006 Benjamin Herrenschmidt, IBM Corp.
   *			 <benh@kernel.crashing.org>
   *    and		 Arnd Bergmann, IBM Corp.
   *    Merged from powerpc/kernel/of_platform.c and
   *    sparc{,64}/kernel/of_device.c by Stephen Rothwell
   *
   *  This program is free software; you can redistribute it and/or
   *  modify it under the terms of the GNU General Public License
   *  as published by the Free Software Foundation; either version
   *  2 of the License, or (at your option) any later version.
   *
   */
  
  #define pr_fmt(fmt)	"OF: " fmt
  
  #include <linux/errno.h>
  #include <linux/module.h>
  #include <linux/amba/bus.h>
  #include <linux/device.h>
  #include <linux/dma-mapping.h>
  #include <linux/slab.h>
  #include <linux/of_address.h>
  #include <linux/of_device.h>
  #include <linux/of_iommu.h>
  #include <linux/of_irq.h>
  #include <linux/of_platform.h>
  #include <linux/platform_device.h>
  
  const struct of_device_id of_default_bus_match_table[] = {
  	{ .compatible = "simple-bus", },
  	{ .compatible = "simple-mfd", },
  	{ .compatible = "isa", },
  #ifdef CONFIG_ARM_AMBA
  	{ .compatible = "arm,amba-bus", },
  #endif /* CONFIG_ARM_AMBA */
  	{} /* Empty terminated list */
  };
  
  static int of_dev_node_match(struct device *dev, void *data)
  {
  	return dev->of_node == data;
  }
  
  /**
   * of_find_device_by_node - Find the platform_device associated with a node
   * @np: Pointer to device tree node
   *
   * Takes a reference to the embedded struct device which needs to be dropped
   * after use.
   *
   * Returns platform_device pointer, or NULL if not found
   */
  struct platform_device *of_find_device_by_node(struct device_node *np)
  {
  	struct device *dev;
  
  	dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
  	return dev ? to_platform_device(dev) : NULL;
  }
  EXPORT_SYMBOL(of_find_device_by_node);
  
  #ifdef CONFIG_OF_ADDRESS
  /*
   * The following routines scan a subtree and registers a device for
   * each applicable node.
   *
   * Note: sparc doesn't use these routines because it has a different
   * mechanism for creating devices from device tree nodes.
   */
  
  /**
   * of_device_make_bus_id - Use the device node data to assign a unique name
   * @dev: pointer to device structure that is linked to a device tree node
   *
   * This routine will first try using the translated bus address to
   * derive a unique name. If it cannot, then it will prepend names from
   * parent nodes until a unique name can be derived.
   */
  static void of_device_make_bus_id(struct device *dev)
  {
  	struct device_node *node = dev->of_node;
  	const __be32 *reg;
  	u64 addr;
  
  	/* Construct the name, using parent nodes if necessary to ensure uniqueness */
  	while (node->parent) {
  		/*
  		 * If the address can be translated, then that is as much
  		 * uniqueness as we need. Make it the first component and return
  		 */
  		reg = of_get_property(node, "reg", NULL);
  		if (reg && (addr = of_translate_address(node, reg)) != OF_BAD_ADDR) {
  			dev_set_name(dev, dev_name(dev) ? "%llx.%s:%s" : "%llx.%s",
  				     (unsigned long long)addr, node->name,
  				     dev_name(dev));
  			return;
  		}
  
  		/* format arguments only used if dev_name() resolves to NULL */
  		dev_set_name(dev, dev_name(dev) ? "%s:%s" : "%s",
  			     kbasename(node->full_name), dev_name(dev));
  		node = node->parent;
  	}
  }
  
  /**
   * of_device_alloc - Allocate and initialize an of_device
   * @np: device node to assign to device
   * @bus_id: Name to assign to the device.  May be null to use default name.
   * @parent: Parent device.
   */
  struct platform_device *of_device_alloc(struct device_node *np,
  				  const char *bus_id,
  				  struct device *parent)
  {
  	struct platform_device *dev;
  	int rc, i, num_reg = 0, num_irq;
  	struct resource *res, temp_res;
  
  	dev = platform_device_alloc("", PLATFORM_DEVID_NONE);
  	if (!dev)
  		return NULL;
  
  	/* count the io and irq resources */
  	while (of_address_to_resource(np, num_reg, &temp_res) == 0)
  		num_reg++;
  	num_irq = of_irq_count(np);
  
  	/* Populate the resource table */
  	if (num_irq || num_reg) {
  		res = kzalloc(sizeof(*res) * (num_irq + num_reg), GFP_KERNEL);
  		if (!res) {
  			platform_device_put(dev);
  			return NULL;
  		}
  
  		dev->num_resources = num_reg + num_irq;
  		dev->resource = res;
  		for (i = 0; i < num_reg; i++, res++) {
  			rc = of_address_to_resource(np, i, res);
  			WARN_ON(rc);
  		}
  		if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
  			pr_debug("not all legacy IRQ resources mapped for %s\n",
  				 np->name);
  	}
  
  	dev->dev.of_node = of_node_get(np);
  	dev->dev.fwnode = &np->fwnode;
  	dev->dev.parent = parent ? : &platform_bus;
  
  	if (bus_id)
  		dev_set_name(&dev->dev, "%s", bus_id);
  	else
  		of_device_make_bus_id(&dev->dev);
  
  	return dev;
  }
  EXPORT_SYMBOL(of_device_alloc);
  
  /**
   * of_platform_device_create_pdata - Alloc, initialize and register an of_device
   * @np: pointer to node to create device for
   * @bus_id: name to assign device
   * @platform_data: pointer to populate platform_data pointer with
   * @parent: Linux device model parent device.
   *
   * Returns pointer to created platform device, or NULL if a device was not
   * registered.  Unavailable devices will not get registered.
   */
  static struct platform_device *of_platform_device_create_pdata(
  					struct device_node *np,
  					const char *bus_id,
  					void *platform_data,
  					struct device *parent)
  {
  	struct platform_device *dev;
  
  	if (!of_device_is_available(np) ||
  	    of_node_test_and_set_flag(np, OF_POPULATED))
  		return NULL;
  
  	dev = of_device_alloc(np, bus_id, parent);
  	if (!dev)
  		goto err_clear_flag;
  
  	dev->dev.bus = &platform_bus_type;
  	dev->dev.platform_data = platform_data;
  	of_msi_configure(&dev->dev, dev->dev.of_node);
  
  	if (of_device_add(dev) != 0) {
  		platform_device_put(dev);
  		goto err_clear_flag;
  	}
  
  	return dev;
  
  err_clear_flag:
  	of_node_clear_flag(np, OF_POPULATED);
  	return NULL;
  }
  
  /**
   * of_platform_device_create - Alloc, initialize and register an of_device
   * @np: pointer to node to create device for
   * @bus_id: name to assign device
   * @parent: Linux device model parent device.
   *
   * Returns pointer to created platform device, or NULL if a device was not
   * registered.  Unavailable devices will not get registered.
   */
  struct platform_device *of_platform_device_create(struct device_node *np,
  					    const char *bus_id,
  					    struct device *parent)
  {
  	return of_platform_device_create_pdata(np, bus_id, NULL, parent);
  }
  EXPORT_SYMBOL(of_platform_device_create);
  
  #ifdef CONFIG_ARM_AMBA
  static struct amba_device *of_amba_device_create(struct device_node *node,
  						 const char *bus_id,
  						 void *platform_data,
  						 struct device *parent)
  {
  	struct amba_device *dev;
  	const void *prop;
  	int i, ret;
  
  	pr_debug("Creating amba device %pOF\n", node);
  
  	if (!of_device_is_available(node) ||
  	    of_node_test_and_set_flag(node, OF_POPULATED))
  		return NULL;
  
  	dev = amba_device_alloc(NULL, 0, 0);
  	if (!dev)
  		goto err_clear_flag;
  
  	/* setup generic device info */
  	dev->dev.of_node = of_node_get(node);
  	dev->dev.fwnode = &node->fwnode;
  	dev->dev.parent = parent ? : &platform_bus;
  	dev->dev.platform_data = platform_data;
  	if (bus_id)
  		dev_set_name(&dev->dev, "%s", bus_id);
  	else
  		of_device_make_bus_id(&dev->dev);
  
  	/* Allow the HW Peripheral ID to be overridden */
  	prop = of_get_property(node, "arm,primecell-periphid", NULL);
  	if (prop)
  		dev->periphid = of_read_ulong(prop, 1);
  
  	/* Decode the IRQs and address ranges */
  	for (i = 0; i < AMBA_NR_IRQS; i++)
  		dev->irq[i] = irq_of_parse_and_map(node, i);
  
  	ret = of_address_to_resource(node, 0, &dev->res);
  	if (ret) {
  		pr_err("amba: of_address_to_resource() failed (%d) for %pOF\n",
  		       ret, node);
  		goto err_free;
  	}
  
  	ret = amba_device_add(dev, &iomem_resource);
  	if (ret) {
  		pr_err("amba_device_add() failed (%d) for %pOF\n",
  		       ret, node);
  		goto err_free;
  	}
  
  	return dev;
  
  err_free:
  	amba_device_put(dev);
  err_clear_flag:
  	of_node_clear_flag(node, OF_POPULATED);
  	return NULL;
  }
  #else /* CONFIG_ARM_AMBA */
  static struct amba_device *of_amba_device_create(struct device_node *node,
  						 const char *bus_id,
  						 void *platform_data,
  						 struct device *parent)
  {
  	return NULL;
  }
  #endif /* CONFIG_ARM_AMBA */
  
  /**
   * of_devname_lookup() - Given a device node, lookup the preferred Linux name
   */
  static const struct of_dev_auxdata *of_dev_lookup(const struct of_dev_auxdata *lookup,
  				 struct device_node *np)
  {
  	const struct of_dev_auxdata *auxdata;
  	struct resource res;
  	int compatible = 0;
  
  	if (!lookup)
  		return NULL;
  
  	auxdata = lookup;
  	for (; auxdata->compatible; auxdata++) {
  		if (!of_device_is_compatible(np, auxdata->compatible))
  			continue;
  		compatible++;
  		if (!of_address_to_resource(np, 0, &res))
  			if (res.start != auxdata->phys_addr)
  				continue;
  		pr_debug("%pOF: devname=%s\n", np, auxdata->name);
  		return auxdata;
  	}
  
  	if (!compatible)
  		return NULL;
  
  	/* Try compatible match if no phys_addr and name are specified */
  	auxdata = lookup;
  	for (; auxdata->compatible; auxdata++) {
  		if (!of_device_is_compatible(np, auxdata->compatible))
  			continue;
  		if (!auxdata->phys_addr && !auxdata->name) {
  			pr_debug("%pOF: compatible match\n", np);
  			return auxdata;
  		}
  	}
  
  	return NULL;
  }
  
  /**
   * of_platform_bus_create() - Create a device for a node and its children.
   * @bus: device node of the bus to instantiate
   * @matches: match table for bus nodes
   * @lookup: auxdata table for matching id and platform_data with device nodes
   * @parent: parent for new device, or NULL for top level.
   * @strict: require compatible property
   *
   * Creates a platform_device for the provided device_node, and optionally
   * recursively create devices for all the child nodes.
   */
  static int of_platform_bus_create(struct device_node *bus,
  				  const struct of_device_id *matches,
  				  const struct of_dev_auxdata *lookup,
  				  struct device *parent, bool strict)
  {
  	const struct of_dev_auxdata *auxdata;
  	struct device_node *child;
  	struct platform_device *dev;
  	const char *bus_id = NULL;
  	void *platform_data = NULL;
  	int rc = 0;
  
  	/* Make sure it has a compatible property */
  	if (strict && (!of_get_property(bus, "compatible", NULL))) {
  		pr_debug("%s() - skipping %pOF, no compatible prop\n",
  			 __func__, bus);
  		return 0;
  	}
  
  	if (of_node_check_flag(bus, OF_POPULATED_BUS)) {
  		pr_debug("%s() - skipping %pOF, already populated\n",
  			__func__, bus);
  		return 0;
  	}
  
  	auxdata = of_dev_lookup(lookup, bus);
  	if (auxdata) {
  		bus_id = auxdata->name;
  		platform_data = auxdata->platform_data;
  	}
  
  	if (of_device_is_compatible(bus, "arm,primecell")) {
  		/*
  		 * Don't return an error here to keep compatibility with older
  		 * device tree files.
  		 */
  		of_amba_device_create(bus, bus_id, platform_data, parent);
  		return 0;
  	}
  
  	dev = of_platform_device_create_pdata(bus, bus_id, platform_data, parent);
  	if (!dev || !of_match_node(matches, bus))
  		return 0;
  
  	for_each_child_of_node(bus, child) {
  		pr_debug("   create child: %pOF\n", child);
  		rc = of_platform_bus_create(child, matches, lookup, &dev->dev, strict);
  		if (rc) {
  			of_node_put(child);
  			break;
  		}
  	}
  	of_node_set_flag(bus, OF_POPULATED_BUS);
  	return rc;
  }
  
  /**
   * of_platform_bus_probe() - Probe the device-tree for platform buses
   * @root: parent of the first level to probe or NULL for the root of the tree
   * @matches: match table for bus nodes
   * @parent: parent to hook devices from, NULL for toplevel
   *
   * Note that children of the provided root are not instantiated as devices
   * unless the specified root itself matches the bus list and is not NULL.
   */
  int of_platform_bus_probe(struct device_node *root,
  			  const struct of_device_id *matches,
  			  struct device *parent)
  {
  	struct device_node *child;
  	int rc = 0;
  
  	root = root ? of_node_get(root) : of_find_node_by_path("/");
  	if (!root)
  		return -EINVAL;
  
  	pr_debug("%s()\n", __func__);
  	pr_debug(" starting at: %pOF\n", root);
  
  	/* Do a self check of bus type, if there's a match, create children */
  	if (of_match_node(matches, root)) {
  		rc = of_platform_bus_create(root, matches, NULL, parent, false);
  	} else for_each_child_of_node(root, child) {
  		if (!of_match_node(matches, child))
  			continue;
  		rc = of_platform_bus_create(child, matches, NULL, parent, false);
  		if (rc) {
  			of_node_put(child);
  			break;
  		}
  	}
  
  	of_node_put(root);
  	return rc;
  }
  EXPORT_SYMBOL(of_platform_bus_probe);
  
  /**
   * of_platform_populate() - Populate platform_devices from device tree data
   * @root: parent of the first level to probe or NULL for the root of the tree
   * @matches: match table, NULL to use the default
   * @lookup: auxdata table for matching id and platform_data with device nodes
   * @parent: parent to hook devices from, NULL for toplevel
   *
   * Similar to of_platform_bus_probe(), this function walks the device tree
   * and creates devices from nodes.  It differs in that it follows the modern
   * convention of requiring all device nodes to have a 'compatible' property,
   * and it is suitable for creating devices which are children of the root
   * node (of_platform_bus_probe will only create children of the root which
   * are selected by the @matches argument).
   *
   * New board support should be using this function instead of
   * of_platform_bus_probe().
   *
   * Returns 0 on success, < 0 on failure.
   */
  int of_platform_populate(struct device_node *root,
  			const struct of_device_id *matches,
  			const struct of_dev_auxdata *lookup,
  			struct device *parent)
  {
  	struct device_node *child;
  	int rc = 0;
  
  	root = root ? of_node_get(root) : of_find_node_by_path("/");
  	if (!root)
  		return -EINVAL;
  
  	pr_debug("%s()\n", __func__);
  	pr_debug(" starting at: %pOF\n", root);
  
  	for_each_child_of_node(root, child) {
  		rc = of_platform_bus_create(child, matches, lookup, parent, true);
  		if (rc) {
  			of_node_put(child);
  			break;
  		}
  	}
  	of_node_set_flag(root, OF_POPULATED_BUS);
  
  	of_node_put(root);
  	return rc;
  }
  EXPORT_SYMBOL_GPL(of_platform_populate);
  
  int of_platform_default_populate(struct device_node *root,
  				 const struct of_dev_auxdata *lookup,
  				 struct device *parent)
  {
  	return of_platform_populate(root, of_default_bus_match_table, lookup,
  				    parent);
  }
  EXPORT_SYMBOL_GPL(of_platform_default_populate);
  
  #ifndef CONFIG_PPC
  static const struct of_device_id reserved_mem_matches[] = {
  	{ .compatible = "qcom,rmtfs-mem" },
  	{ .compatible = "ramoops" },
  	{}
  };
  
  static int __init of_platform_default_populate_init(void)
  {
  	struct device_node *node;
  
  	if (!of_have_populated_dt())
  		return -ENODEV;
  
  	/*
  	 * Handle certain compatibles explicitly, since we don't want to create
  	 * platform_devices for every node in /reserved-memory with a
  	 * "compatible",
  	 */
  	for_each_matching_node(node, reserved_mem_matches)
  		of_platform_device_create(node, NULL, NULL);
  
  	/* Populate everything else. */
  	of_platform_default_populate(NULL, NULL, NULL);
  
  	return 0;
  }
  arch_initcall_sync(of_platform_default_populate_init);
  #endif
  
  int of_platform_device_destroy(struct device *dev, void *data)
  {
  	/* Do not touch devices not populated from the device tree */
  	if (!dev->of_node || !of_node_check_flag(dev->of_node, OF_POPULATED))
  		return 0;
  
  	/* Recurse for any nodes that were treated as busses */
  	if (of_node_check_flag(dev->of_node, OF_POPULATED_BUS))
  		device_for_each_child(dev, NULL, of_platform_device_destroy);
  
  	if (dev->bus == &platform_bus_type)
  		platform_device_unregister(to_platform_device(dev));
  #ifdef CONFIG_ARM_AMBA
  	else if (dev->bus == &amba_bustype)
  		amba_device_unregister(to_amba_device(dev));
  #endif
  
  	of_node_clear_flag(dev->of_node, OF_POPULATED);
  	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(of_platform_device_destroy);
  
  /**
   * of_platform_depopulate() - Remove devices populated from device tree
   * @parent: device which children will be removed
   *
   * Complementary to of_platform_populate(), this function removes children
   * of the given device (and, recurrently, their children) that have been
   * created from their respective device tree nodes (and only those,
   * leaving others - eg. manually created - unharmed).
   */
  void of_platform_depopulate(struct device *parent)
  {
  	if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
  		device_for_each_child(parent, NULL, of_platform_device_destroy);
  		of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
  	}
  }
  EXPORT_SYMBOL_GPL(of_platform_depopulate);
  
  static void devm_of_platform_populate_release(struct device *dev, void *res)
  {
  	of_platform_depopulate(*(struct device **)res);
  }
  
  /**
   * devm_of_platform_populate() - Populate platform_devices from device tree data
   * @dev: device that requested to populate from device tree data
   *
   * Similar to of_platform_populate(), but will automatically call
   * of_platform_depopulate() when the device is unbound from the bus.
   *
   * Returns 0 on success, < 0 on failure.
   */
  int devm_of_platform_populate(struct device *dev)
  {
  	struct device **ptr;
  	int ret;
  
  	if (!dev)
  		return -EINVAL;
  
  	ptr = devres_alloc(devm_of_platform_populate_release,
  			   sizeof(*ptr), GFP_KERNEL);
  	if (!ptr)
  		return -ENOMEM;
  
  	ret = of_platform_populate(dev->of_node, NULL, NULL, dev);
  	if (ret) {
  		devres_free(ptr);
  	} else {
  		*ptr = dev;
  		devres_add(dev, ptr);
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(devm_of_platform_populate);
  
  static int devm_of_platform_match(struct device *dev, void *res, void *data)
  {
  	struct device **ptr = res;
  
  	if (!ptr) {
  		WARN_ON(!ptr);
  		return 0;
  	}
  
  	return *ptr == data;
  }
  
  /**
   * devm_of_platform_depopulate() - Remove devices populated from device tree
   * @dev: device that requested to depopulate from device tree data
   *
   * Complementary to devm_of_platform_populate(), this function removes children
   * of the given device (and, recurrently, their children) that have been
   * created from their respective device tree nodes (and only those,
   * leaving others - eg. manually created - unharmed).
   */
  void devm_of_platform_depopulate(struct device *dev)
  {
  	int ret;
  
  	ret = devres_release(dev, devm_of_platform_populate_release,
  			     devm_of_platform_match, dev);
  
  	WARN_ON(ret);
  }
  EXPORT_SYMBOL_GPL(devm_of_platform_depopulate);
  
  #ifdef CONFIG_OF_DYNAMIC
  static int of_platform_notify(struct notifier_block *nb,
  				unsigned long action, void *arg)
  {
  	struct of_reconfig_data *rd = arg;
  	struct platform_device *pdev_parent, *pdev;
  	bool children_left;
  
  	switch (of_reconfig_get_state_change(action, rd)) {
  	case OF_RECONFIG_CHANGE_ADD:
  		/* verify that the parent is a bus */
  		if (!of_node_check_flag(rd->dn->parent, OF_POPULATED_BUS))
  			return NOTIFY_OK;	/* not for us */
  
  		/* already populated? (driver using of_populate manually) */
  		if (of_node_check_flag(rd->dn, OF_POPULATED))
  			return NOTIFY_OK;
  
  		/* pdev_parent may be NULL when no bus platform device */
  		pdev_parent = of_find_device_by_node(rd->dn->parent);
  		pdev = of_platform_device_create(rd->dn, NULL,
  				pdev_parent ? &pdev_parent->dev : NULL);
  		of_dev_put(pdev_parent);
  
  		if (pdev == NULL) {
  			pr_err("%s: failed to create for '%pOF'\n",
  					__func__, rd->dn);
  			/* of_platform_device_create tosses the error code */
  			return notifier_from_errno(-EINVAL);
  		}
  		break;
  
  	case OF_RECONFIG_CHANGE_REMOVE:
  
  		/* already depopulated? */
  		if (!of_node_check_flag(rd->dn, OF_POPULATED))
  			return NOTIFY_OK;
  
  		/* find our device by node */
  		pdev = of_find_device_by_node(rd->dn);
  		if (pdev == NULL)
  			return NOTIFY_OK;	/* no? not meant for us */
  
  		/* unregister takes one ref away */
  		of_platform_device_destroy(&pdev->dev, &children_left);
  
  		/* and put the reference of the find */
  		of_dev_put(pdev);
  		break;
  	}
  
  	return NOTIFY_OK;
  }
  
  static struct notifier_block platform_of_notifier = {
  	.notifier_call = of_platform_notify,
  };
  
  void of_platform_register_reconfig_notifier(void)
  {
  	WARN_ON(of_reconfig_notifier_register(&platform_of_notifier));
  }
  #endif /* CONFIG_OF_DYNAMIC */
  
  #endif /* CONFIG_OF_ADDRESS */
  