acpi_memhotplug.c 14.2 KB
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/*
 * Copyright (C) 2004 Intel Corporation <naveen.b.s@intel.com>
 *
 * All rights reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
 * NON INFRINGEMENT.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 * ACPI based HotPlug driver that supports Memory Hotplug
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 * This driver fields notifications from firmware for memory add
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 * and remove operations and alerts the VM of the affected memory
 * ranges.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/memory_hotplug.h>
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#include <linux/slab.h>
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#include <linux/acpi.h>
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#include <acpi/acpi_drivers.h>

#define ACPI_MEMORY_DEVICE_CLASS		"memory"
#define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
#define ACPI_MEMORY_DEVICE_NAME			"Hotplug Mem Device"

#define _COMPONENT		ACPI_MEMORY_DEVICE_COMPONENT

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#undef PREFIX
#define 	PREFIX		"ACPI:memory_hp:"

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ACPI_MODULE_NAME("acpi_memhotplug");
MODULE_AUTHOR("Naveen B S <naveen.b.s@intel.com>");
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MODULE_DESCRIPTION("Hotplug Mem Driver");
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MODULE_LICENSE("GPL");

/* Memory Device States */
#define MEMORY_INVALID_STATE	0
#define MEMORY_POWER_ON_STATE	1
#define MEMORY_POWER_OFF_STATE	2

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static int acpi_memory_device_add(struct acpi_device *device);
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static int acpi_memory_device_remove(struct acpi_device *device);
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static const struct acpi_device_id memory_device_ids[] = {
	{ACPI_MEMORY_DEVICE_HID, 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, memory_device_ids);

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static struct acpi_driver acpi_memory_device_driver = {
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	.name = "acpi_memhotplug",
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	.class = ACPI_MEMORY_DEVICE_CLASS,
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	.ids = memory_device_ids,
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	.ops = {
		.add = acpi_memory_device_add,
		.remove = acpi_memory_device_remove,
		},
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};

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struct acpi_memory_info {
	struct list_head list;
	u64 start_addr;		/* Memory Range start physical addr */
	u64 length;		/* Memory Range length */
	unsigned short caching;	/* memory cache attribute */
	unsigned short write_protect;	/* memory read/write attribute */
	unsigned int enabled:1;
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	unsigned int failed:1;
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};

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struct acpi_memory_device {
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	struct acpi_device * device;
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	unsigned int state;	/* State of the memory device */
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	struct list_head res_list;
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};

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static acpi_status
acpi_memory_get_resource(struct acpi_resource *resource, void *context)
{
	struct acpi_memory_device *mem_device = context;
	struct acpi_resource_address64 address64;
	struct acpi_memory_info *info, *new;
	acpi_status status;

	status = acpi_resource_to_address64(resource, &address64);
	if (ACPI_FAILURE(status) ||
	    (address64.resource_type != ACPI_MEMORY_RANGE))
		return AE_OK;

	list_for_each_entry(info, &mem_device->res_list, list) {
		/* Can we combine the resource range information? */
		if ((info->caching == address64.info.mem.caching) &&
		    (info->write_protect == address64.info.mem.write_protect) &&
		    (info->start_addr + info->length == address64.minimum)) {
			info->length += address64.address_length;
			return AE_OK;
		}
	}

	new = kzalloc(sizeof(struct acpi_memory_info), GFP_KERNEL);
	if (!new)
		return AE_ERROR;

	INIT_LIST_HEAD(&new->list);
	new->caching = address64.info.mem.caching;
	new->write_protect = address64.info.mem.write_protect;
	new->start_addr = address64.minimum;
	new->length = address64.address_length;
	list_add_tail(&new->list, &mem_device->res_list);

	return AE_OK;
}

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static void
acpi_memory_free_device_resources(struct acpi_memory_device *mem_device)
{
	struct acpi_memory_info *info, *n;

	list_for_each_entry_safe(info, n, &mem_device->res_list, list)
		kfree(info);
	INIT_LIST_HEAD(&mem_device->res_list);
}

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static int
acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
{
	acpi_status status;

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	if (!list_empty(&mem_device->res_list))
		return 0;

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	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
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				     acpi_memory_get_resource, mem_device);
	if (ACPI_FAILURE(status)) {
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		acpi_memory_free_device_resources(mem_device);
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		return -EINVAL;
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	}

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	return 0;
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}

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static int acpi_memory_get_device(acpi_handle handle,
				  struct acpi_memory_device **mem_device)
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{
	struct acpi_device *device = NULL;
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	int result = 0;

	acpi_scan_lock_acquire();
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	acpi_bus_get_device(handle, &device);
	if (device)
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		goto end;

	/*
	 * Now add the notified device.  This creates the acpi_device
	 * and invokes .add function
	 */
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	result = acpi_bus_scan(handle);
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	if (result) {
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		acpi_handle_warn(handle, "ACPI namespace scan failed\n");
		result = -EINVAL;
		goto out;
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	}
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	result = acpi_bus_get_device(handle, &device);
	if (result) {
		acpi_handle_warn(handle, "Missing device object\n");
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		result = -EINVAL;
		goto out;
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	}
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 end:
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	*mem_device = acpi_driver_data(device);
	if (!(*mem_device)) {
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		dev_err(&device->dev, "driver data not found\n");
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		result = -ENODEV;
		goto out;
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	}

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 out:
	acpi_scan_lock_release();
	return result;
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}

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static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
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{
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	unsigned long long current_status;
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	/* Get device present/absent information from the _STA */
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	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle, "_STA",
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					       NULL, &current_status)))
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		return -ENODEV;
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	/*
	 * Check for device status. Device should be
	 * present/enabled/functioning.
	 */
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	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
	      && (current_status & ACPI_STA_DEVICE_ENABLED)
	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
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		return -ENODEV;
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	return 0;
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}

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static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
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{
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	int result, num_enabled = 0;
	struct acpi_memory_info *info;
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	int node;
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	node = acpi_get_node(mem_device->device->handle);
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	/*
	 * Tell the VM there is more memory here...
	 * Note: Assume that this function returns zero on success
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	 * We don't have memory-hot-add rollback function,now.
	 * (i.e. memory-hot-remove function)
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	 */
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	list_for_each_entry(info, &mem_device->res_list, list) {
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		if (info->enabled) { /* just sanity check...*/
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			num_enabled++;
			continue;
		}
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		/*
		 * If the memory block size is zero, please ignore it.
		 * Don't try to do the following memory hotplug flowchart.
		 */
		if (!info->length)
			continue;
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		if (node < 0)
			node = memory_add_physaddr_to_nid(info->start_addr);

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		result = add_memory(node, info->start_addr, info->length);
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		/*
		 * If the memory block has been used by the kernel, add_memory()
		 * returns -EEXIST. If add_memory() returns the other error, it
		 * means that this memory block is not used by the kernel.
		 */
		if (result && result != -EEXIST) {
			info->failed = 1;
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			continue;
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		}

		if (!result)
			info->enabled = 1;
		/*
		 * Add num_enable even if add_memory() returns -EEXIST, so the
		 * device is bound to this driver.
		 */
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		num_enabled++;
	}
	if (!num_enabled) {
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		dev_err(&mem_device->device->dev, "add_memory failed\n");
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		mem_device->state = MEMORY_INVALID_STATE;
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		return -EINVAL;
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	}
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	/*
	 * Sometimes the memory device will contain several memory blocks.
	 * When one memory block is hot-added to the system memory, it will
	 * be regarded as a success.
	 * Otherwise if the last memory block can't be hot-added to the system
	 * memory, it will be failure and the memory device can't be bound with
	 * driver.
	 */
	return 0;
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}

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static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
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{
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	int result = 0, nid;
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	struct acpi_memory_info *info, *n;
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	nid = acpi_get_node(mem_device->device->handle);

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	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
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		if (info->failed)
			/* The kernel does not use this memory block */
			continue;

		if (!info->enabled)
			/*
			 * The kernel uses this memory block, but it may be not
			 * managed by us.
			 */
			return -EBUSY;

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		if (nid < 0)
			nid = memory_add_physaddr_to_nid(info->start_addr);
		result = remove_memory(nid, info->start_addr, info->length);
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		if (result)
			return result;
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		list_del(&info->list);
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		kfree(info);
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	}

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	return result;
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}

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static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
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{
	struct acpi_memory_device *mem_device;
	struct acpi_device *device;
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	struct acpi_eject_event *ej_event = NULL;
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	u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */
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	acpi_status status;
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	switch (event) {
	case ACPI_NOTIFY_BUS_CHECK:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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				  "\nReceived BUS CHECK notification for device\n"));
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		/* Fall Through */
	case ACPI_NOTIFY_DEVICE_CHECK:
		if (event == ACPI_NOTIFY_DEVICE_CHECK)
			ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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					  "\nReceived DEVICE CHECK notification for device\n"));
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		if (acpi_memory_get_device(handle, &mem_device)) {
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			acpi_handle_err(handle, "Cannot find driver data\n");
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			break;
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		}

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		ost_code = ACPI_OST_SC_SUCCESS;
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		break;
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	case ACPI_NOTIFY_EJECT_REQUEST:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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				  "\nReceived EJECT REQUEST notification for device\n"));
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		status = AE_ERROR;
		acpi_scan_lock_acquire();

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		if (acpi_bus_get_device(handle, &device)) {
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			acpi_handle_err(handle, "Device doesn't exist\n");
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			goto unlock;
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		}
		mem_device = acpi_driver_data(device);
		if (!mem_device) {
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			acpi_handle_err(handle, "Driver Data is NULL\n");
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			goto unlock;
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		}

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		ej_event = kmalloc(sizeof(*ej_event), GFP_KERNEL);
		if (!ej_event) {
			pr_err(PREFIX "No memory, dropping EJECT\n");
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			goto unlock;
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		}

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		get_device(&device->dev);
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		ej_event->device = device;
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		ej_event->event = ACPI_NOTIFY_EJECT_REQUEST;
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		/* The eject is carried out asynchronously. */
		status = acpi_os_hotplug_execute(acpi_bus_hot_remove_device,
						 ej_event);
		if (ACPI_FAILURE(status)) {
			put_device(&device->dev);
			kfree(ej_event);
		}
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 unlock:
		acpi_scan_lock_release();
		if (ACPI_SUCCESS(status))
			return;
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	default:
		ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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				  "Unsupported event [0x%x]\n", event));
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		/* non-hotplug event; possibly handled by other handler */
		return;
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	}

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	/* Inform firmware that the hotplug operation has completed */
	(void) acpi_evaluate_hotplug_ost(handle, event, ost_code, NULL);
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}

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static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
{
	if (!mem_device)
		return;

	acpi_memory_free_device_resources(mem_device);
	kfree(mem_device);
}

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static int acpi_memory_device_add(struct acpi_device *device)
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{
	int result;
	struct acpi_memory_device *mem_device = NULL;


	if (!device)
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		return -EINVAL;
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	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
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	if (!mem_device)
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		return -ENOMEM;
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	INIT_LIST_HEAD(&mem_device->res_list);
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	mem_device->device = device;
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	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
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	device->driver_data = mem_device;
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	/* Get the range from the _CRS */
	result = acpi_memory_get_device_resources(mem_device);
	if (result) {
		kfree(mem_device);
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		return result;
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	}

	/* Set the device state */
	mem_device->state = MEMORY_POWER_ON_STATE;

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	pr_debug("%s\n", acpi_device_name(device));
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	if (!acpi_memory_check_device(mem_device)) {
		/* call add_memory func */
		result = acpi_memory_enable_device(mem_device);
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		if (result) {
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			dev_err(&device->dev,
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				"Error in acpi_memory_enable_device\n");
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			acpi_memory_device_free(mem_device);
		}
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	}
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	return result;
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}

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static int acpi_memory_device_remove(struct acpi_device *device)
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{
	struct acpi_memory_device *mem_device = NULL;
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	int result;
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	if (!device || !acpi_driver_data(device))
		return -EINVAL;

	mem_device = acpi_driver_data(device);
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	result = acpi_memory_remove_memory(mem_device);
	if (result)
		return result;

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	acpi_memory_device_free(mem_device);
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	return 0;
}

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/*
 * Helper function to check for memory device
 */
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static acpi_status is_memory_device(acpi_handle handle)
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{
	char *hardware_id;
	acpi_status status;
	struct acpi_device_info *info;

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	status = acpi_get_object_info(handle, &info);
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	if (ACPI_FAILURE(status))
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		return status;
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	if (!(info->valid & ACPI_VALID_HID)) {
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		kfree(info);
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		return AE_ERROR;
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	}

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	hardware_id = info->hardware_id.string;
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	if ((hardware_id == NULL) ||
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	    (strcmp(hardware_id, ACPI_MEMORY_DEVICE_HID)))
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		status = AE_ERROR;

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	kfree(info);
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	return status;
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}

static acpi_status
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acpi_memory_register_notify_handler(acpi_handle handle,
				    u32 level, void *ctxt, void **retv)
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{
	acpi_status status;


	status = is_memory_device(handle);
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	if (ACPI_FAILURE(status))
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		return AE_OK;	/* continue */
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	status = acpi_install_notify_handler(handle, ACPI_SYSTEM_NOTIFY,
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					     acpi_memory_device_notify, NULL);
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	/* continue */
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	return AE_OK;
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}

static acpi_status
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acpi_memory_deregister_notify_handler(acpi_handle handle,
				      u32 level, void *ctxt, void **retv)
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{
	acpi_status status;


	status = is_memory_device(handle);
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	if (ACPI_FAILURE(status))
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		return AE_OK;	/* continue */
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	status = acpi_remove_notify_handler(handle,
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					    ACPI_SYSTEM_NOTIFY,
					    acpi_memory_device_notify);
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	return AE_OK;	/* continue */
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}

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static int __init acpi_memory_device_init(void)
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{
	int result;
	acpi_status status;


	result = acpi_bus_register_driver(&acpi_memory_device_driver);

	if (result < 0)
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		return -ENODEV;
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	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
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				     ACPI_UINT32_MAX,
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				     acpi_memory_register_notify_handler, NULL,
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				     NULL, NULL);
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	if (ACPI_FAILURE(status)) {
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		ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
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		acpi_bus_unregister_driver(&acpi_memory_device_driver);
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		return -ENODEV;
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	}
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	return 0;
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}

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static void __exit acpi_memory_device_exit(void)
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{
	acpi_status status;


	/*
	 * Adding this to un-install notification handlers for all the device
	 * handles.
	 */
	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
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				     ACPI_UINT32_MAX,
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				     acpi_memory_deregister_notify_handler, NULL,
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				     NULL, NULL);
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	if (ACPI_FAILURE(status))
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		ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
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	acpi_bus_unregister_driver(&acpi_memory_device_driver);

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	return;
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}

module_init(acpi_memory_device_init);
module_exit(acpi_memory_device_exit);