v4.19.13 snapshot.
diff --git a/drivers/base/platform.c b/drivers/base/platform.c
new file mode 100644
index 0000000..dff82a3
--- /dev/null
+++ b/drivers/base/platform.c
@@ -0,0 +1,1488 @@
+// 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 "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)
+{
+	int 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)
+{
+	int 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)
+{
+	int i, 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 >= 0) {
+		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)
+{
+	int 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;
+
+		*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));
+	}
+}
+