1 files changed, 353 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
new file mode 100644
index 000000000..b02fd51e5
--- /dev/null
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -0,0 +1,353 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2004, 2013 Intel Corporation
+ * Author: Naveen B S <naveen.b.s@intel.com>
+ * Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * All rights reserved.
+ *
+ * ACPI based HotPlug driver that supports Memory Hotplug
+ * This driver fields notifications from firmware for memory add
+ * and remove operations and alerts the VM of the affected memory
+ * ranges.
+ */
+
+#include <linux/acpi.h>
+#include <linux/memory.h>
+#include <linux/memory_hotplug.h>
+
+#include "internal.h"
+
+#define ACPI_MEMORY_DEVICE_CLASS		"memory"
+#define ACPI_MEMORY_DEVICE_HID			"PNP0C80"
+#define ACPI_MEMORY_DEVICE_NAME			"Hotplug Mem Device"
+
+static const struct acpi_device_id memory_device_ids[] = {
+	{ACPI_MEMORY_DEVICE_HID, 0},
+	{"", 0},
+};
+
+#ifdef CONFIG_ACPI_HOTPLUG_MEMORY
+
+static int acpi_memory_device_add(struct acpi_device *device,
+				  const struct acpi_device_id *not_used);
+static void acpi_memory_device_remove(struct acpi_device *device);
+
+static struct acpi_scan_handler memory_device_handler = {
+	.ids = memory_device_ids,
+	.attach = acpi_memory_device_add,
+	.detach = acpi_memory_device_remove,
+	.hotplug = {
+		.enabled = true,
+	},
+};
+
+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;
+};
+
+struct acpi_memory_device {
+	struct acpi_device *device;
+	struct list_head res_list;
+};
+
+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.address.minimum)) {
+			info->length += address64.address.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.address.minimum;
+	new->length = address64.address.address_length;
+	list_add_tail(&new->list, &mem_device->res_list);
+
+	return AE_OK;
+}
+
+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);
+}
+
+static int
+acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
+{
+	acpi_status status;
+
+	if (!list_empty(&mem_device->res_list))
+		return 0;
+
+	status = acpi_walk_resources(mem_device->device->handle, METHOD_NAME__CRS,
+				     acpi_memory_get_resource, mem_device);
+	if (ACPI_FAILURE(status)) {
+		acpi_memory_free_device_resources(mem_device);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int acpi_memory_check_device(struct acpi_memory_device *mem_device)
+{
+	unsigned long long current_status;
+
+	/* Get device present/absent information from the _STA */
+	if (ACPI_FAILURE(acpi_evaluate_integer(mem_device->device->handle,
+					       METHOD_NAME__STA, NULL,
+					       &current_status)))
+		return -ENODEV;
+	/*
+	 * Check for device status. Device should be
+	 * present/enabled/functioning.
+	 */
+	if (!((current_status & ACPI_STA_DEVICE_PRESENT)
+	      && (current_status & ACPI_STA_DEVICE_ENABLED)
+	      && (current_status & ACPI_STA_DEVICE_FUNCTIONING)))
+		return -ENODEV;
+
+	return 0;
+}
+
+static int acpi_bind_memblk(struct memory_block *mem, void *arg)
+{
+	return acpi_bind_one(&mem->dev, arg);
+}
+
+static int acpi_bind_memory_blocks(struct acpi_memory_info *info,
+				   struct acpi_device *adev)
+{
+	return walk_memory_blocks(info->start_addr, info->length, adev,
+				  acpi_bind_memblk);
+}
+
+static int acpi_unbind_memblk(struct memory_block *mem, void *arg)
+{
+	acpi_unbind_one(&mem->dev);
+	return 0;
+}
+
+static void acpi_unbind_memory_blocks(struct acpi_memory_info *info)
+{
+	walk_memory_blocks(info->start_addr, info->length, NULL,
+			   acpi_unbind_memblk);
+}
+
+static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
+{
+	acpi_handle handle = mem_device->device->handle;
+	int result, num_enabled = 0;
+	struct acpi_memory_info *info;
+	int node;
+
+	node = acpi_get_node(handle);
+	/*
+	 * Tell the VM there is more memory here...
+	 * Note: Assume that this function returns zero on success
+	 * We don't have memory-hot-add rollback function,now.
+	 * (i.e. memory-hot-remove function)
+	 */
+	list_for_each_entry(info, &mem_device->res_list, list) {
+		if (info->enabled) { /* just sanity check...*/
+			num_enabled++;
+			continue;
+		}
+		/*
+		 * If the memory block size is zero, please ignore it.
+		 * Don't try to do the following memory hotplug flowchart.
+		 */
+		if (!info->length)
+			continue;
+		if (node < 0)
+			node = memory_add_physaddr_to_nid(info->start_addr);
+
+		result = __add_memory(node, info->start_addr, info->length,
+				      MHP_NONE);
+
+		/*
+		 * 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)
+			continue;
+
+		result = acpi_bind_memory_blocks(info, mem_device->device);
+		if (result) {
+			acpi_unbind_memory_blocks(info);
+			return -ENODEV;
+		}
+
+		info->enabled = 1;
+
+		/*
+		 * Add num_enable even if add_memory() returns -EEXIST, so the
+		 * device is bound to this driver.
+		 */
+		num_enabled++;
+	}
+	if (!num_enabled) {
+		dev_err(&mem_device->device->dev, "add_memory failed\n");
+		return -EINVAL;
+	}
+	/*
+	 * 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;
+}
+
+static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
+{
+	acpi_handle handle = mem_device->device->handle;
+	struct acpi_memory_info *info, *n;
+	int nid = acpi_get_node(handle);
+
+	list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
+		if (!info->enabled)
+			continue;
+
+		if (nid == NUMA_NO_NODE)
+			nid = memory_add_physaddr_to_nid(info->start_addr);
+
+		acpi_unbind_memory_blocks(info);
+		__remove_memory(nid, info->start_addr, info->length);
+		list_del(&info->list);
+		kfree(info);
+	}
+}
+
+static void acpi_memory_device_free(struct acpi_memory_device *mem_device)
+{
+	if (!mem_device)
+		return;
+
+	acpi_memory_free_device_resources(mem_device);
+	mem_device->device->driver_data = NULL;
+	kfree(mem_device);
+}
+
+static int acpi_memory_device_add(struct acpi_device *device,
+				  const struct acpi_device_id *not_used)
+{
+	struct acpi_memory_device *mem_device;
+	int result;
+
+	if (!device)
+		return -EINVAL;
+
+	mem_device = kzalloc(sizeof(struct acpi_memory_device), GFP_KERNEL);
+	if (!mem_device)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&mem_device->res_list);
+	mem_device->device = device;
+	sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
+	sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
+	device->driver_data = mem_device;
+
+	/* Get the range from the _CRS */
+	result = acpi_memory_get_device_resources(mem_device);
+	if (result) {
+		device->driver_data = NULL;
+		kfree(mem_device);
+		return result;
+	}
+
+	result = acpi_memory_check_device(mem_device);
+	if (result) {
+		acpi_memory_device_free(mem_device);
+		return 0;
+	}
+
+	result = acpi_memory_enable_device(mem_device);
+	if (result) {
+		dev_err(&device->dev, "acpi_memory_enable_device() error\n");
+		acpi_memory_device_free(mem_device);
+		return result;
+	}
+
+	dev_dbg(&device->dev, "Memory device configured by ACPI\n");
+	return 1;
+}
+
+static void acpi_memory_device_remove(struct acpi_device *device)
+{
+	struct acpi_memory_device *mem_device;
+
+	if (!device || !acpi_driver_data(device))
+		return;
+
+	mem_device = acpi_driver_data(device);
+	acpi_memory_remove_memory(mem_device);
+	acpi_memory_device_free(mem_device);
+}
+
+static bool __initdata acpi_no_memhotplug;
+
+void __init acpi_memory_hotplug_init(void)
+{
+	if (acpi_no_memhotplug) {
+		memory_device_handler.attach = NULL;
+		acpi_scan_add_handler(&memory_device_handler);
+		return;
+	}
+	acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
+}
+
+static int __init disable_acpi_memory_hotplug(char *str)
+{
+	acpi_no_memhotplug = true;
+	return 1;
+}
+__setup("acpi_no_memhotplug", disable_acpi_memory_hotplug);
+
+#else
+
+static struct acpi_scan_handler memory_device_handler = {
+	.ids = memory_device_ids,
+};
+
+void __init acpi_memory_hotplug_init(void)
+{
+	acpi_scan_add_handler(&memory_device_handler);
+}
+
+#endif /* CONFIG_ACPI_HOTPLUG_MEMORY */