text: // SPDX-License-Identifier: GPL-2.0
  /*
   * platform.c - platform 'pseudo' bus for legacy devices
   *
   * Copyright (c) 2002-3 Patrick Mochel
   * Copyright (c) 2002-3 Open Source Development Labs
   *
   * Please see Documentation/driver-model/platform.txt for more
   * information.
   */
  
  #include <linux/string.h>
  #include <linux/platform_device.h>
  #include <linux/of_device.h>
  #include <linux/of_irq.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/dma-mapping.h>
  #include <linux/bootmem.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include <linux/pm_runtime.h>
  #include <linux/pm_domain.h>
  #include <linux/idr.h>
  #include <linux/acpi.h>
  #include <linux/clk/clk-conf.h>
  #include <linux/limits.h>
  #include <linux/property.h>
  #include <linux/kmemleak.h>
  #include <linux/types.h>
  
  #include "base.h"
  #include "power/power.h"
  
  /* For automatically allocated device IDs */
  static DEFINE_IDA(platform_devid_ida);
  
  struct device platform_bus = {
  	.init_name	= "platform",
  };
  EXPORT_SYMBOL_GPL(platform_bus);
  
  /**
   * arch_setup_pdev_archdata - Allow manipulation of archdata before its used
   * @pdev: platform device
   *
   * This is called before platform_device_add() such that any pdev_archdata may
   * be setup before the platform_notifier is called.  So if a user needs to
   * manipulate any relevant information in the pdev_archdata they can do:
   *
   *	platform_device_alloc()
   *	... manipulate ...
   *	platform_device_add()
   *
   * And if they don't care they can just call platform_device_register() and
   * everything will just work out.
   */
  void __weak arch_setup_pdev_archdata(struct platform_device *pdev)
  {
  }
  
  /**
   * platform_get_resource - get a resource for a device
   * @dev: platform device
   * @type: resource type
   * @num: resource index
   */
  struct resource *platform_get_resource(struct platform_device *dev,
  				       unsigned int type, unsigned int num)
  {
  	u32 i;
  
  	for (i = 0; i < dev->num_resources; i++) {
  		struct resource *r = &dev->resource[i];
  
  		if (type == resource_type(r) && num-- == 0)
  			return r;
  	}
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(platform_get_resource);
  
  /**
   * platform_get_irq - get an IRQ for a device
   * @dev: platform device
   * @num: IRQ number index
   */
  int platform_get_irq(struct platform_device *dev, unsigned int num)
  {
  #ifdef CONFIG_SPARC
  	/* sparc does not have irqs represented as IORESOURCE_IRQ resources */
  	if (!dev || num >= dev->archdata.num_irqs)
  		return -ENXIO;
  	return dev->archdata.irqs[num];
  #else
  	struct resource *r;
  	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) {
  		int ret;
  
  		ret = of_irq_get(dev->dev.of_node, num);
  		if (ret > 0 || ret == -EPROBE_DEFER)
  			return ret;
  	}
  
  	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
  	if (has_acpi_companion(&dev->dev)) {
  		if (r && r->flags & IORESOURCE_DISABLED) {
  			int ret;
  
  			ret = acpi_irq_get(ACPI_HANDLE(&dev->dev), num, r);
  			if (ret)
  				return ret;
  		}
  	}
  
  	/*
  	 * The resources may pass trigger flags to the irqs that need
  	 * to be set up. It so happens that the trigger flags for
  	 * IORESOURCE_BITS correspond 1-to-1 to the IRQF_TRIGGER*
  	 * settings.
  	 */
  	if (r && r->flags & IORESOURCE_BITS) {
  		struct irq_data *irqd;
  
  		irqd = irq_get_irq_data(r->start);
  		if (!irqd)
  			return -ENXIO;
  		irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
  	}
  
  	return r ? r->start : -ENXIO;
  #endif
  }
  EXPORT_SYMBOL_GPL(platform_get_irq);
  
  /**
   * platform_irq_count - Count the number of IRQs a platform device uses
   * @dev: platform device
   *
   * Return: Number of IRQs a platform device uses or EPROBE_DEFER
   */
  int platform_irq_count(struct platform_device *dev)
  {
  	int ret, nr = 0;
  
  	while ((ret = platform_get_irq(dev, nr)) >= 0)
  		nr++;
  
  	if (ret == -EPROBE_DEFER)
  		return ret;
  
  	return nr;
  }
  EXPORT_SYMBOL_GPL(platform_irq_count);
  
  /**
   * platform_get_resource_byname - get a resource for a device by name
   * @dev: platform device
   * @type: resource type
   * @name: resource name
   */
  struct resource *platform_get_resource_byname(struct platform_device *dev,
  					      unsigned int type,
  					      const char *name)
  {
  	u32 i;
  
  	for (i = 0; i < dev->num_resources; i++) {
  		struct resource *r = &dev->resource[i];
  
  		if (unlikely(!r->name))
  			continue;
  
  		if (type == resource_type(r) && !strcmp(r->name, name))
  			return r;
  	}
  	return NULL;
  }
  EXPORT_SYMBOL_GPL(platform_get_resource_byname);
  
  /**
   * platform_get_irq_byname - get an IRQ for a device by name
   * @dev: platform device
   * @name: IRQ name
   */
  int platform_get_irq_byname(struct platform_device *dev, const char *name)
  {
  	struct resource *r;
  
  	if (IS_ENABLED(CONFIG_OF_IRQ) && dev->dev.of_node) {
  		int ret;
  
  		ret = of_irq_get_byname(dev->dev.of_node, name);
  		if (ret > 0 || ret == -EPROBE_DEFER)
  			return ret;
  	}
  
  	r = platform_get_resource_byname(dev, IORESOURCE_IRQ, name);
  	return r ? r->start : -ENXIO;
  }
  EXPORT_SYMBOL_GPL(platform_get_irq_byname);
  
  /**
   * platform_add_devices - add a numbers of platform devices
   * @devs: array of platform devices to add
   * @num: number of platform devices in array
   */
  int platform_add_devices(struct platform_device **devs, int num)
  {
  	int i, ret = 0;
  
  	for (i = 0; i < num; i++) {
  		ret = platform_device_register(devs[i]);
  		if (ret) {
  			while (--i >= 0)
  				platform_device_unregister(devs[i]);
  			break;
  		}
  	}
  
  	return ret;
  }
  EXPORT_SYMBOL_GPL(platform_add_devices);
  
  struct platform_object {
  	struct platform_device pdev;
  	char name[];
  };
  
  /**
   * platform_device_put - destroy a platform device
   * @pdev: platform device to free
   *
   * Free all memory associated with a platform device.  This function must
   * _only_ be externally called in error cases.  All other usage is a bug.
   */
  void platform_device_put(struct platform_device *pdev)
  {
  	if (pdev)
  		put_device(&pdev->dev);
  }
  EXPORT_SYMBOL_GPL(platform_device_put);
  
  static void platform_device_release(struct device *dev)
  {
  	struct platform_object *pa = container_of(dev, struct platform_object,
  						  pdev.dev);
  
  	of_device_node_put(&pa->pdev.dev);
  	kfree(pa->pdev.dev.platform_data);
  	kfree(pa->pdev.mfd_cell);
  	kfree(pa->pdev.resource);
  	kfree(pa->pdev.driver_override);
  	kfree(pa);
  }
  
  /**
   * platform_device_alloc - create a platform device
   * @name: base name of the device we're adding
   * @id: instance id
   *
   * Create a platform device object which can have other objects attached
   * to it, and which will have attached objects freed when it is released.
   */
  struct platform_device *platform_device_alloc(const char *name, int id)
  {
  	struct platform_object *pa;
  
  	pa = kzalloc(sizeof(*pa) + strlen(name) + 1, GFP_KERNEL);
  	if (pa) {
  		strcpy(pa->name, name);
  		pa->pdev.name = pa->name;
  		pa->pdev.id = id;
  		device_initialize(&pa->pdev.dev);
  		pa->pdev.dev.release = platform_device_release;
  		arch_setup_pdev_archdata(&pa->pdev);
  	}
  
  	return pa ? &pa->pdev : NULL;
  }
  EXPORT_SYMBOL_GPL(platform_device_alloc);
  
  /**
   * platform_device_add_resources - add resources to a platform device
   * @pdev: platform device allocated by platform_device_alloc to add resources to
   * @res: set of resources that needs to be allocated for the device
   * @num: number of resources
   *
   * Add a copy of the resources to the platform device.  The memory
   * associated with the resources will be freed when the platform device is
   * released.
   */
  int platform_device_add_resources(struct platform_device *pdev,
  				  const struct resource *res, unsigned int num)
  {
  	struct resource *r = NULL;
  
  	if (res) {
  		r = kmemdup(res, sizeof(struct resource) * num, GFP_KERNEL);
  		if (!r)
  			return -ENOMEM;
  	}
  
  	kfree(pdev->resource);
  	pdev->resource = r;
  	pdev->num_resources = num;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(platform_device_add_resources);
  
  /**
   * platform_device_add_data - add platform-specific data to a platform device
   * @pdev: platform device allocated by platform_device_alloc to add resources to
   * @data: platform specific data for this platform device
   * @size: size of platform specific data
   *
   * Add a copy of platform specific data to the platform device's
   * platform_data pointer.  The memory associated with the platform data
   * will be freed when the platform device is released.
   */
  int platform_device_add_data(struct platform_device *pdev, const void *data,
  			     size_t size)
  {
  	void *d = NULL;
  
  	if (data) {
  		d = kmemdup(data, size, GFP_KERNEL);
  		if (!d)
  			return -ENOMEM;
  	}
  
  	kfree(pdev->dev.platform_data);
  	pdev->dev.platform_data = d;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(platform_device_add_data);
  
  /**
   * platform_device_add_properties - add built-in properties to a platform device
   * @pdev: platform device to add properties to
   * @properties: null terminated array of properties to add
   *
   * The function will take deep copy of @properties and attach the copy to the
   * platform device. The memory associated with properties will be freed when the
   * platform device is released.
   */
  int platform_device_add_properties(struct platform_device *pdev,
  				   const struct property_entry *properties)
  {
  	return device_add_properties(&pdev->dev, properties);
  }
  EXPORT_SYMBOL_GPL(platform_device_add_properties);
  
  /**
   * platform_device_add - add a platform device to device hierarchy
   * @pdev: platform device we're adding
   *
   * This is part 2 of platform_device_register(), though may be called
   * separately _iff_ pdev was allocated by platform_device_alloc().
   */
  int platform_device_add(struct platform_device *pdev)
  {
  	u32 i;
  	int ret;
  
  	if (!pdev)
  		return -EINVAL;
  
  	if (!pdev->dev.parent)
  		pdev->dev.parent = &platform_bus;
  
  	pdev->dev.bus = &platform_bus_type;
  
  	switch (pdev->id) {
  	default:
  		dev_set_name(&pdev->dev, "%s.%d", pdev->name,  pdev->id);
  		break;
  	case PLATFORM_DEVID_NONE:
  		dev_set_name(&pdev->dev, "%s", pdev->name);
  		break;
  	case PLATFORM_DEVID_AUTO:
  		/*
  		 * Automatically allocated device ID. We mark it as such so
  		 * that we remember it must be freed, and we append a suffix
  		 * to avoid namespace collision with explicit IDs.
  		 */
  		ret = ida_simple_get(&platform_devid_ida, 0, 0, GFP_KERNEL);
  		if (ret < 0)
  			goto err_out;
  		pdev->id = ret;
  		pdev->id_auto = true;
  		dev_set_name(&pdev->dev, "%s.%d.auto", pdev->name, pdev->id);
  		break;
  	}
  
  	for (i = 0; i < pdev->num_resources; i++) {
  		struct resource *p, *r = &pdev->resource[i];
  
  		if (r->name == NULL)
  			r->name = dev_name(&pdev->dev);
  
  		p = r->parent;
  		if (!p) {
  			if (resource_type(r) == IORESOURCE_MEM)
  				p = &iomem_resource;
  			else if (resource_type(r) == IORESOURCE_IO)
  				p = &ioport_resource;
  		}
  
  		if (p && insert_resource(p, r)) {
  			dev_err(&pdev->dev, "failed to claim resource %d: %pR\n", i, r);
  			ret = -EBUSY;
  			goto failed;
  		}
  	}
  
  	pr_debug("Registering platform device '%s'. Parent at %s\n",
  		 dev_name(&pdev->dev), dev_name(pdev->dev.parent));
  
  	ret = device_add(&pdev->dev);
  	if (ret == 0)
  		return ret;
  
   failed:
  	if (pdev->id_auto) {
  		ida_simple_remove(&platform_devid_ida, pdev->id);
  		pdev->id = PLATFORM_DEVID_AUTO;
  	}
  
  	while (i--) {
  		struct resource *r = &pdev->resource[i];
  		if (r->parent)
  			release_resource(r);
  	}
  
   err_out:
  	return ret;
  }
  EXPORT_SYMBOL_GPL(platform_device_add);
  
  /**
   * platform_device_del - remove a platform-level device
   * @pdev: platform device we're removing
   *
   * Note that this function will also release all memory- and port-based
   * resources owned by the device (@dev->resource).  This function must
   * _only_ be externally called in error cases.  All other usage is a bug.
   */
  void platform_device_del(struct platform_device *pdev)
  {
  	u32 i;
  
  	if (pdev) {
  		device_remove_properties(&pdev->dev);
  		device_del(&pdev->dev);
  
  		if (pdev->id_auto) {
  			ida_simple_remove(&platform_devid_ida, pdev->id);
  			pdev->id = PLATFORM_DEVID_AUTO;
  		}
  
  		for (i = 0; i < pdev->num_resources; i++) {
  			struct resource *r = &pdev->resource[i];
  			if (r->parent)
  				release_resource(r);
  		}
  	}
  }
  EXPORT_SYMBOL_GPL(platform_device_del);
  
  /**
   * platform_device_register - add a platform-level device
   * @pdev: platform device we're adding
   */
  int platform_device_register(struct platform_device *pdev)
  {
  	device_initialize(&pdev->dev);
  	arch_setup_pdev_archdata(pdev);
  	return platform_device_add(pdev);
  }
  EXPORT_SYMBOL_GPL(platform_device_register);
  
  /**
   * platform_device_unregister - unregister a platform-level device
   * @pdev: platform device we're unregistering
   *
   * Unregistration is done in 2 steps. First we release all resources
   * and remove it from the subsystem, then we drop reference count by
   * calling platform_device_put().
   */
  void platform_device_unregister(struct platform_device *pdev)
  {
  	platform_device_del(pdev);
  	platform_device_put(pdev);
  }
  EXPORT_SYMBOL_GPL(platform_device_unregister);
  
  /**
   * platform_device_register_full - add a platform-level device with
   * resources and platform-specific data
   *
   * @pdevinfo: data used to create device
   *
   * Returns &struct platform_device pointer on success, or ERR_PTR() on error.
   */
  struct platform_device *platform_device_register_full(
  		const struct platform_device_info *pdevinfo)
  {
  	int ret = -ENOMEM;
  	struct platform_device *pdev;
  
  	pdev = platform_device_alloc(pdevinfo->name, pdevinfo->id);
  	if (!pdev)
  		goto err_alloc;
  
  	pdev->dev.parent = pdevinfo->parent;
  	pdev->dev.fwnode = pdevinfo->fwnode;
  
  	if (pdevinfo->dma_mask) {
  		/*
  		 * This memory isn't freed when the device is put,
  		 * I don't have a nice idea for that though.  Conceptually
  		 * dma_mask in struct device should not be a pointer.
  		 * See http://thread.gmane.org/gmane.linux.kernel.pci/9081
  		 */
  		pdev->dev.dma_mask =
  			kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
  		if (!pdev->dev.dma_mask)
  			goto err;
  
  		kmemleak_ignore(pdev->dev.dma_mask);
  
  		*pdev->dev.dma_mask = pdevinfo->dma_mask;
  		pdev->dev.coherent_dma_mask = pdevinfo->dma_mask;
  	}
  
  	ret = platform_device_add_resources(pdev,
  			pdevinfo->res, pdevinfo->num_res);
  	if (ret)
  		goto err;
  
  	ret = platform_device_add_data(pdev,
  			pdevinfo->data, pdevinfo->size_data);
  	if (ret)
  		goto err;
  
  	if (pdevinfo->properties) {
  		ret = platform_device_add_properties(pdev,
  						     pdevinfo->properties);
  		if (ret)
  			goto err;
  	}
  
  	ret = platform_device_add(pdev);
  	if (ret) {
  err:
  		ACPI_COMPANION_SET(&pdev->dev, NULL);
  		kfree(pdev->dev.dma_mask);
  
  err_alloc:
  		platform_device_put(pdev);
  		return ERR_PTR(ret);
  	}
  
  	return pdev;
  }
  EXPORT_SYMBOL_GPL(platform_device_register_full);
  
  static int platform_drv_probe(struct device *_dev)
  {
  	struct platform_driver *drv = to_platform_driver(_dev->driver);
  	struct platform_device *dev = to_platform_device(_dev);
  	int ret;
  
  	ret = of_clk_set_defaults(_dev->of_node, false);
  	if (ret < 0)
  		return ret;
  
  	ret = dev_pm_domain_attach(_dev, true);
  	if (ret)
  		goto out;
  
  	if (drv->probe) {
  		ret = drv->probe(dev);
  		if (ret)
  			dev_pm_domain_detach(_dev, true);
  	}
  
  out:
  	if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
  		dev_warn(_dev, "probe deferral not supported\n");
  		ret = -ENXIO;
  	}
  
  	return ret;
  }
  
  static int platform_drv_probe_fail(struct device *_dev)
  {
  	return -ENXIO;
  }
  
  static int platform_drv_remove(struct device *_dev)
  {
  	struct platform_driver *drv = to_platform_driver(_dev->driver);
  	struct platform_device *dev = to_platform_device(_dev);
  	int ret = 0;
  
  	if (drv->remove)
  		ret = drv->remove(dev);
  	dev_pm_domain_detach(_dev, true);
  
  	return ret;
  }
  
  static void platform_drv_shutdown(struct device *_dev)
  {
  	struct platform_driver *drv = to_platform_driver(_dev->driver);
  	struct platform_device *dev = to_platform_device(_dev);
  
  	if (drv->shutdown)
  		drv->shutdown(dev);
  }
  
  /**
   * __platform_driver_register - register a driver for platform-level devices
   * @drv: platform driver structure
   * @owner: owning module/driver
   */
  int __platform_driver_register(struct platform_driver *drv,
  				struct module *owner)
  {
  	drv->driver.owner = owner;
  	drv->driver.bus = &platform_bus_type;
  	drv->driver.probe = platform_drv_probe;
  	drv->driver.remove = platform_drv_remove;
  	drv->driver.shutdown = platform_drv_shutdown;
  
  	return driver_register(&drv->driver);
  }
  EXPORT_SYMBOL_GPL(__platform_driver_register);
  
  /**
   * platform_driver_unregister - unregister a driver for platform-level devices
   * @drv: platform driver structure
   */
  void platform_driver_unregister(struct platform_driver *drv)
  {
  	driver_unregister(&drv->driver);
  }
  EXPORT_SYMBOL_GPL(platform_driver_unregister);
  
  /**
   * __platform_driver_probe - register driver for non-hotpluggable device
   * @drv: platform driver structure
   * @probe: the driver probe routine, probably from an __init section
   * @module: module which will be the owner of the driver
   *
   * Use this instead of platform_driver_register() when you know the device
   * is not hotpluggable and has already been registered, and you want to
   * remove its run-once probe() infrastructure from memory after the driver
   * has bound to the device.
   *
   * One typical use for this would be with drivers for controllers integrated
   * into system-on-chip processors, where the controller devices have been
   * configured as part of board setup.
   *
   * Note that this is incompatible with deferred probing.
   *
   * Returns zero if the driver registered and bound to a device, else returns
   * a negative error code and with the driver not registered.
   */
  int __init_or_module __platform_driver_probe(struct platform_driver *drv,
  		int (*probe)(struct platform_device *), struct module *module)
  {
  	int retval, code;
  
  	if (drv->driver.probe_type == PROBE_PREFER_ASYNCHRONOUS) {
  		pr_err("%s: drivers registered with %s can not be probed asynchronously\n",
  			 drv->driver.name, __func__);
  		return -EINVAL;
  	}
  
  	/*
  	 * We have to run our probes synchronously because we check if
  	 * we find any devices to bind to and exit with error if there
  	 * are any.
  	 */
  	drv->driver.probe_type = PROBE_FORCE_SYNCHRONOUS;
  
  	/*
  	 * Prevent driver from requesting probe deferral to avoid further
  	 * futile probe attempts.
  	 */
  	drv->prevent_deferred_probe = true;
  
  	/* make sure driver won't have bind/unbind attributes */
  	drv->driver.suppress_bind_attrs = true;
  
  	/* temporary section violation during probe() */
  	drv->probe = probe;
  	retval = code = __platform_driver_register(drv, module);
  
  	/*
  	 * Fixup that section violation, being paranoid about code scanning
  	 * the list of drivers in order to probe new devices.  Check to see
  	 * if the probe was successful, and make sure any forced probes of
  	 * new devices fail.
  	 */
  	spin_lock(&drv->driver.bus->p->klist_drivers.k_lock);
  	drv->probe = NULL;
  	if (code == 0 && list_empty(&drv->driver.p->klist_devices.k_list))
  		retval = -ENODEV;
  	drv->driver.probe = platform_drv_probe_fail;
  	spin_unlock(&drv->driver.bus->p->klist_drivers.k_lock);
  
  	if (code != retval)
  		platform_driver_unregister(drv);
  	return retval;
  }
  EXPORT_SYMBOL_GPL(__platform_driver_probe);
  
  /**
   * __platform_create_bundle - register driver and create corresponding device
   * @driver: platform driver structure
   * @probe: the driver probe routine, probably from an __init section
   * @res: set of resources that needs to be allocated for the device
   * @n_res: number of resources
   * @data: platform specific data for this platform device
   * @size: size of platform specific data
   * @module: module which will be the owner of the driver
   *
   * Use this in legacy-style modules that probe hardware directly and
   * register a single platform device and corresponding platform driver.
   *
   * Returns &struct platform_device pointer on success, or ERR_PTR() on error.
   */
  struct platform_device * __init_or_module __platform_create_bundle(
  			struct platform_driver *driver,
  			int (*probe)(struct platform_device *),
  			struct resource *res, unsigned int n_res,
  			const void *data, size_t size, struct module *module)
  {
  	struct platform_device *pdev;
  	int error;
  
  	pdev = platform_device_alloc(driver->driver.name, -1);
  	if (!pdev) {
  		error = -ENOMEM;
  		goto err_out;
  	}
  
  	error = platform_device_add_resources(pdev, res, n_res);
  	if (error)
  		goto err_pdev_put;
  
  	error = platform_device_add_data(pdev, data, size);
  	if (error)
  		goto err_pdev_put;
  
  	error = platform_device_add(pdev);
  	if (error)
  		goto err_pdev_put;
  
  	error = __platform_driver_probe(driver, probe, module);
  	if (error)
  		goto err_pdev_del;
  
  	return pdev;
  
  err_pdev_del:
  	platform_device_del(pdev);
  err_pdev_put:
  	platform_device_put(pdev);
  err_out:
  	return ERR_PTR(error);
  }
  EXPORT_SYMBOL_GPL(__platform_create_bundle);
  
  /**
   * __platform_register_drivers - register an array of platform drivers
   * @drivers: an array of drivers to register
   * @count: the number of drivers to register
   * @owner: module owning the drivers
   *
   * Registers platform drivers specified by an array. On failure to register a
   * driver, all previously registered drivers will be unregistered. Callers of
   * this API should use platform_unregister_drivers() to unregister drivers in
   * the reverse order.
   *
   * Returns: 0 on success or a negative error code on failure.
   */
  int __platform_register_drivers(struct platform_driver * const *drivers,
  				unsigned int count, struct module *owner)
  {
  	unsigned int i;
  	int err;
  
  	for (i = 0; i < count; i++) {
  		pr_debug("registering platform driver %ps\n", drivers[i]);
  
  		err = __platform_driver_register(drivers[i], owner);
  		if (err < 0) {
  			pr_err("failed to register platform driver %ps: %d\n",
  			       drivers[i], err);
  			goto error;
  		}
  	}
  
  	return 0;
  
  error:
  	while (i--) {
  		pr_debug("unregistering platform driver %ps\n", drivers[i]);
  		platform_driver_unregister(drivers[i]);
  	}
  
  	return err;
  }
  EXPORT_SYMBOL_GPL(__platform_register_drivers);
  
  /**
   * platform_unregister_drivers - unregister an array of platform drivers
   * @drivers: an array of drivers to unregister
   * @count: the number of drivers to unregister
   *
   * Unegisters platform drivers specified by an array. This is typically used
   * to complement an earlier call to platform_register_drivers(). Drivers are
   * unregistered in the reverse order in which they were registered.
   */
  void platform_unregister_drivers(struct platform_driver * const *drivers,
  				 unsigned int count)
  {
  	while (count--) {
  		pr_debug("unregistering platform driver %ps\n", drivers[count]);
  		platform_driver_unregister(drivers[count]);
  	}
  }
  EXPORT_SYMBOL_GPL(platform_unregister_drivers);
  
  /* modalias support enables more hands-off userspace setup:
   * (a) environment variable lets new-style hotplug events work once system is
   *     fully running:  "modprobe $MODALIAS"
   * (b) sysfs attribute lets new-style coldplug recover from hotplug events
   *     mishandled before system is fully running:  "modprobe $(cat modalias)"
   */
  static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
  			     char *buf)
  {
  	struct platform_device	*pdev = to_platform_device(dev);
  	int len;
  
  	len = of_device_modalias(dev, buf, PAGE_SIZE);
  	if (len != -ENODEV)
  		return len;
  
  	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
  	if (len != -ENODEV)
  		return len;
  
  	len = snprintf(buf, PAGE_SIZE, "platform:%s\n", pdev->name);
  
  	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
  }
  static DEVICE_ATTR_RO(modalias);
  
  static ssize_t driver_override_store(struct device *dev,
  				     struct device_attribute *attr,
  				     const char *buf, size_t count)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	char *driver_override, *old, *cp;
  
  	/* We need to keep extra room for a newline */
  	if (count >= (PAGE_SIZE - 1))
  		return -EINVAL;
  
  	driver_override = kstrndup(buf, count, GFP_KERNEL);
  	if (!driver_override)
  		return -ENOMEM;
  
  	cp = strchr(driver_override, '\n');
  	if (cp)
  		*cp = '\0';
  
  	device_lock(dev);
  	old = pdev->driver_override;
  	if (strlen(driver_override)) {
  		pdev->driver_override = driver_override;
  	} else {
  		kfree(driver_override);
  		pdev->driver_override = NULL;
  	}
  	device_unlock(dev);
  
  	kfree(old);
  
  	return count;
  }
  
  static ssize_t driver_override_show(struct device *dev,
  				    struct device_attribute *attr, char *buf)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	ssize_t len;
  
  	device_lock(dev);
  	len = sprintf(buf, "%s\n", pdev->driver_override);
  	device_unlock(dev);
  	return len;
  }
  static DEVICE_ATTR_RW(driver_override);
  
  
  static struct attribute *platform_dev_attrs[] = {
  	&dev_attr_modalias.attr,
  	&dev_attr_driver_override.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(platform_dev);
  
  static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct platform_device	*pdev = to_platform_device(dev);
  	int rc;
  
  	/* Some devices have extra OF data and an OF-style MODALIAS */
  	rc = of_device_uevent_modalias(dev, env);
  	if (rc != -ENODEV)
  		return rc;
  
  	rc = acpi_device_uevent_modalias(dev, env);
  	if (rc != -ENODEV)
  		return rc;
  
  	add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX,
  			pdev->name);
  	return 0;
  }
  
  static const struct platform_device_id *platform_match_id(
  			const struct platform_device_id *id,
  			struct platform_device *pdev)
  {
  	while (id->name[0]) {
  		if (strcmp(pdev->name, id->name) == 0) {
  			pdev->id_entry = id;
  			return id;
  		}
  		id++;
  	}
  	return NULL;
  }
  
  /**
   * platform_match - bind platform device to platform driver.
   * @dev: device.
   * @drv: driver.
   *
   * Platform device IDs are assumed to be encoded like this:
   * "<name><instance>", where <name> is a short description of the type of
   * device, like "pci" or "floppy", and <instance> is the enumerated
   * instance of the device, like '0' or '42'.  Driver IDs are simply
   * "<name>".  So, extract the <name> from the platform_device structure,
   * and compare it against the name of the driver. Return whether they match
   * or not.
   */
  static int platform_match(struct device *dev, struct device_driver *drv)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct platform_driver *pdrv = to_platform_driver(drv);
  
  	/* When driver_override is set, only bind to the matching driver */
  	if (pdev->driver_override)
  		return !strcmp(pdev->driver_override, drv->name);
  
  	/* Attempt an OF style match first */
  	if (of_driver_match_device(dev, drv))
  		return 1;
  
  	/* Then try ACPI style match */
  	if (acpi_driver_match_device(dev, drv))
  		return 1;
  
  	/* Then try to match against the id table */
  	if (pdrv->id_table)
  		return platform_match_id(pdrv->id_table, pdev) != NULL;
  
  	/* fall-back to driver name match */
  	return (strcmp(pdev->name, drv->name) == 0);
  }
  
  #ifdef CONFIG_PM_SLEEP
  
  static int platform_legacy_suspend(struct device *dev, pm_message_t mesg)
  {
  	struct platform_driver *pdrv = to_platform_driver(dev->driver);
  	struct platform_device *pdev = to_platform_device(dev);
  	int ret = 0;
  
  	if (dev->driver && pdrv->suspend)
  		ret = pdrv->suspend(pdev, mesg);
  
  	return ret;
  }
  
  static int platform_legacy_resume(struct device *dev)
  {
  	struct platform_driver *pdrv = to_platform_driver(dev->driver);
  	struct platform_device *pdev = to_platform_device(dev);
  	int ret = 0;
  
  	if (dev->driver && pdrv->resume)
  		ret = pdrv->resume(pdev);
  
  	return ret;
  }
  
  #endif /* CONFIG_PM_SLEEP */
  
  #ifdef CONFIG_SUSPEND
  
  int platform_pm_suspend(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->suspend)
  			ret = drv->pm->suspend(dev);
  	} else {
  		ret = platform_legacy_suspend(dev, PMSG_SUSPEND);
  	}
  
  	return ret;
  }
  
  int platform_pm_resume(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->resume)
  			ret = drv->pm->resume(dev);
  	} else {
  		ret = platform_legacy_resume(dev);
  	}
  
  	return ret;
  }
  
  #endif /* CONFIG_SUSPEND */
  
  #ifdef CONFIG_HIBERNATE_CALLBACKS
  
  int platform_pm_freeze(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->freeze)
  			ret = drv->pm->freeze(dev);
  	} else {
  		ret = platform_legacy_suspend(dev, PMSG_FREEZE);
  	}
  
  	return ret;
  }
  
  int platform_pm_thaw(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->thaw)
  			ret = drv->pm->thaw(dev);
  	} else {
  		ret = platform_legacy_resume(dev);
  	}
  
  	return ret;
  }
  
  int platform_pm_poweroff(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->poweroff)
  			ret = drv->pm->poweroff(dev);
  	} else {
  		ret = platform_legacy_suspend(dev, PMSG_HIBERNATE);
  	}
  
  	return ret;
  }
  
  int platform_pm_restore(struct device *dev)
  {
  	struct device_driver *drv = dev->driver;
  	int ret = 0;
  
  	if (!drv)
  		return 0;
  
  	if (drv->pm) {
  		if (drv->pm->restore)
  			ret = drv->pm->restore(dev);
  	} else {
  		ret = platform_legacy_resume(dev);
  	}
  
  	return ret;
  }
  
  #endif /* CONFIG_HIBERNATE_CALLBACKS */
  
  int platform_dma_configure(struct device *dev)
  {
  	enum dev_dma_attr attr;
  	int ret = 0;
  
  	if (dev->of_node) {
  		ret = of_dma_configure(dev, dev->of_node, true);
  	} else if (has_acpi_companion(dev)) {
  		attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
  		if (attr != DEV_DMA_NOT_SUPPORTED)
  			ret = acpi_dma_configure(dev, attr);
  	}
  
  	return ret;
  }
  
  static const struct dev_pm_ops platform_dev_pm_ops = {
  	.runtime_suspend = pm_generic_runtime_suspend,
  	.runtime_resume = pm_generic_runtime_resume,
  	USE_PLATFORM_PM_SLEEP_OPS
  };
  
  struct bus_type platform_bus_type = {
  	.name		= "platform",
  	.dev_groups	= platform_dev_groups,
  	.match		= platform_match,
  	.uevent		= platform_uevent,
  	.dma_configure	= platform_dma_configure,
  	.pm		= &platform_dev_pm_ops,
  };
  EXPORT_SYMBOL_GPL(platform_bus_type);
  
  int __init platform_bus_init(void)
  {
  	int error;
  
  	early_platform_cleanup();
  
  	error = device_register(&platform_bus);
  	if (error) {
  		put_device(&platform_bus);
  		return error;
  	}
  	error =  bus_register(&platform_bus_type);
  	if (error)
  		device_unregister(&platform_bus);
  	of_platform_register_reconfig_notifier();
  	return error;
  }
  
  #ifndef ARCH_HAS_DMA_GET_REQUIRED_MASK
  u64 dma_get_required_mask(struct device *dev)
  {
  	u32 low_totalram = ((max_pfn - 1) << PAGE_SHIFT);
  	u32 high_totalram = ((max_pfn - 1) >> (32 - PAGE_SHIFT));
  	u64 mask;
  
  	if (!high_totalram) {
  		/* convert to mask just covering totalram */
  		low_totalram = (1 << (fls(low_totalram) - 1));
  		low_totalram += low_totalram - 1;
  		mask = low_totalram;
  	} else {
  		high_totalram = (1 << (fls(high_totalram) - 1));
  		high_totalram += high_totalram - 1;
  		mask = (((u64)high_totalram) << 32) + 0xffffffff;
  	}
  	return mask;
  }
  EXPORT_SYMBOL_GPL(dma_get_required_mask);
  #endif
  
  static __initdata LIST_HEAD(early_platform_driver_list);
  static __initdata LIST_HEAD(early_platform_device_list);
  
  /**
   * early_platform_driver_register - register early platform driver
   * @epdrv: early_platform driver structure
   * @buf: string passed from early_param()
   *
   * Helper function for early_platform_init() / early_platform_init_buffer()
   */
  int __init early_platform_driver_register(struct early_platform_driver *epdrv,
  					  char *buf)
  {
  	char *tmp;
  	int n;
  
  	/* Simply add the driver to the end of the global list.
  	 * Drivers will by default be put on the list in compiled-in order.
  	 */
  	if (!epdrv->list.next) {
  		INIT_LIST_HEAD(&epdrv->list);
  		list_add_tail(&epdrv->list, &early_platform_driver_list);
  	}
  
  	/* If the user has specified device then make sure the driver
  	 * gets prioritized. The driver of the last device specified on
  	 * command line will be put first on the list.
  	 */
  	n = strlen(epdrv->pdrv->driver.name);
  	if (buf && !strncmp(buf, epdrv->pdrv->driver.name, n)) {
  		list_move(&epdrv->list, &early_platform_driver_list);
  
  		/* Allow passing parameters after device name */
  		if (buf[n] == '\0' || buf[n] == ',')
  			epdrv->requested_id = -1;
  		else {
  			epdrv->requested_id = simple_strtoul(&buf[n + 1],
  							     &tmp, 10);
  
  			if (buf[n] != '.' || (tmp == &buf[n + 1])) {
  				epdrv->requested_id = EARLY_PLATFORM_ID_ERROR;
  				n = 0;
  			} else
  				n += strcspn(&buf[n + 1], ",") + 1;
  		}
  
  		if (buf[n] == ',')
  			n++;
  
  		if (epdrv->bufsize) {
  			memcpy(epdrv->buffer, &buf[n],
  			       min_t(int, epdrv->bufsize, strlen(&buf[n]) + 1));
  			epdrv->buffer[epdrv->bufsize - 1] = '\0';
  		}
  	}
  
  	return 0;
  }
  
  /**
   * early_platform_add_devices - adds a number of early platform devices
   * @devs: array of early platform devices to add
   * @num: number of early platform devices in array
   *
   * Used by early architecture code to register early platform devices and
   * their platform data.
   */
  void __init early_platform_add_devices(struct platform_device **devs, int num)
  {
  	struct device *dev;
  	int i;
  
  	/* simply add the devices to list */
  	for (i = 0; i < num; i++) {
  		dev = &devs[i]->dev;
  
  		if (!dev->devres_head.next) {
  			pm_runtime_early_init(dev);
  			INIT_LIST_HEAD(&dev->devres_head);
  			list_add_tail(&dev->devres_head,
  				      &early_platform_device_list);
  		}
  	}
  }
  
  /**
   * early_platform_driver_register_all - register early platform drivers
   * @class_str: string to identify early platform driver class
   *
   * Used by architecture code to register all early platform drivers
   * for a certain class. If omitted then only early platform drivers
   * with matching kernel command line class parameters will be registered.
   */
  void __init early_platform_driver_register_all(char *class_str)
  {
  	/* The "class_str" parameter may or may not be present on the kernel
  	 * command line. If it is present then there may be more than one
  	 * matching parameter.
  	 *
  	 * Since we register our early platform drivers using early_param()
  	 * we need to make sure that they also get registered in the case
  	 * when the parameter is missing from the kernel command line.
  	 *
  	 * We use parse_early_options() to make sure the early_param() gets
  	 * called at least once. The early_param() may be called more than
  	 * once since the name of the preferred device may be specified on
  	 * the kernel command line. early_platform_driver_register() handles
  	 * this case for us.
  	 */
  	parse_early_options(class_str);
  }
  
  /**
   * early_platform_match - find early platform device matching driver
   * @epdrv: early platform driver structure
   * @id: id to match against
   */
  static struct platform_device * __init
  early_platform_match(struct early_platform_driver *epdrv, int id)
  {
  	struct platform_device *pd;
  
  	list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
  		if (platform_match(&pd->dev, &epdrv->pdrv->driver))
  			if (pd->id == id)
  				return pd;
  
  	return NULL;
  }
  
  /**
   * early_platform_left - check if early platform driver has matching devices
   * @epdrv: early platform driver structure
   * @id: return true if id or above exists
   */
  static int __init early_platform_left(struct early_platform_driver *epdrv,
  				       int id)
  {
  	struct platform_device *pd;
  
  	list_for_each_entry(pd, &early_platform_device_list, dev.devres_head)
  		if (platform_match(&pd->dev, &epdrv->pdrv->driver))
  			if (pd->id >= id)
  				return 1;
  
  	return 0;
  }
  
  /**
   * early_platform_driver_probe_id - probe drivers matching class_str and id
   * @class_str: string to identify early platform driver class
   * @id: id to match against
   * @nr_probe: number of platform devices to successfully probe before exiting
   */
  static int __init early_platform_driver_probe_id(char *class_str,
  						 int id,
  						 int nr_probe)
  {
  	struct early_platform_driver *epdrv;
  	struct platform_device *match;
  	int match_id;
  	int n = 0;
  	int left = 0;
  
  	list_for_each_entry(epdrv, &early_platform_driver_list, list) {
  		/* only use drivers matching our class_str */
  		if (strcmp(class_str, epdrv->class_str))
  			continue;
  
  		if (id == -2) {
  			match_id = epdrv->requested_id;
  			left = 1;
  
  		} else {
  			match_id = id;
  			left += early_platform_left(epdrv, id);
  
  			/* skip requested id */
  			switch (epdrv->requested_id) {
  			case EARLY_PLATFORM_ID_ERROR:
  			case EARLY_PLATFORM_ID_UNSET:
  				break;
  			default:
  				if (epdrv->requested_id == id)
  					match_id = EARLY_PLATFORM_ID_UNSET;
  			}
  		}
  
  		switch (match_id) {
  		case EARLY_PLATFORM_ID_ERROR:
  			pr_warn("%s: unable to parse %s parameter\n",
  				class_str, epdrv->pdrv->driver.name);
  			/* fall-through */
  		case EARLY_PLATFORM_ID_UNSET:
  			match = NULL;
  			break;
  		default:
  			match = early_platform_match(epdrv, match_id);
  		}
  
  		if (match) {
  			/*
  			 * Set up a sensible init_name to enable
  			 * dev_name() and others to be used before the
  			 * rest of the driver core is initialized.
  			 */
  			if (!match->dev.init_name && slab_is_available()) {
  				if (match->id != -1)
  					match->dev.init_name =
  						kasprintf(GFP_KERNEL, "%s.%d",
  							  match->name,
  							  match->id);
  				else
  					match->dev.init_name =
  						kasprintf(GFP_KERNEL, "%s",
  							  match->name);
  
  				if (!match->dev.init_name)
  					return -ENOMEM;
  			}
  
  			if (epdrv->pdrv->probe(match))
  				pr_warn("%s: unable to probe %s early.\n",
  					class_str, match->name);
  			else
  				n++;
  		}
  
  		if (n >= nr_probe)
  			break;
  	}
  
  	if (left)
  		return n;
  	else
  		return -ENODEV;
  }
  
  /**
   * early_platform_driver_probe - probe a class of registered drivers
   * @class_str: string to identify early platform driver class
   * @nr_probe: number of platform devices to successfully probe before exiting
   * @user_only: only probe user specified early platform devices
   *
   * Used by architecture code to probe registered early platform drivers
   * within a certain class. For probe to happen a registered early platform
   * device matching a registered early platform driver is needed.
   */
  int __init early_platform_driver_probe(char *class_str,
  				       int nr_probe,
  				       int user_only)
  {
  	int k, n, i;
  
  	n = 0;
  	for (i = -2; n < nr_probe; i++) {
  		k = early_platform_driver_probe_id(class_str, i, nr_probe - n);
  
  		if (k < 0)
  			break;
  
  		n += k;
  
  		if (user_only)
  			break;
  	}
  
  	return n;
  }
  
  /**
   * early_platform_cleanup - clean up early platform code
   */
  void __init early_platform_cleanup(void)
  {
  	struct platform_device *pd, *pd2;
  
  	/* clean up the devres list used to chain devices */
  	list_for_each_entry_safe(pd, pd2, &early_platform_device_list,
  				 dev.devres_head) {
  		list_del(&pd->dev.devres_head);
  		memset(&pd->dev.devres_head, 0, sizeof(pd->dev.devres_head));
  	}
  }
  
  