acpi_memhotplug.c

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/*
 * Copyright (C) 2004 Intel Corporation <[email protected]>
 *
 * 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
 * This driver fields notifications from firmware for memory add
 * 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>
#include <linux/slab.h>
#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

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

ACPI_MODULE_NAME("acpi_memhotplug");
MODULE_AUTHOR("Naveen B S <[email protected]>");
MODULE_DESCRIPTION("Hotplug Mem Driver");
MODULE_LICENSE("GPL");

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

static int acpi_memory_device_add(struct acpi_device *device);
static int acpi_memory_device_remove(struct acpi_device *device, int type);

static const struct acpi_device_id memory_device_ids[] = {
    {ACPI_MEMORY_DEVICE_HID, 0},
    {"", 0},
};
MODULE_DEVICE_TABLE(acpi, memory_device_ids);

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

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

static int acpi_hotmem_initialized;

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;
}

static int
acpi_memory_get_device_resources(struct acpi_memory_device *mem_device)
{
    acpi_status status;
    struct acpi_memory_info *info, *n;


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

    return 0;
}

static int
acpi_memory_get_device(acpi_handle handle,
               struct acpi_memory_device **mem_device)
{
    acpi_status status;
    acpi_handle phandle;
    struct acpi_device *device = NULL;
    struct acpi_device *pdevice = NULL;
    int result;


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

    status = acpi_get_parent(handle, &phandle);
    if (ACPI_FAILURE(status)) {
        ACPI_EXCEPTION((AE_INFO, status, "Cannot find acpi parent"));
        return -EINVAL;
    }

    /* Get the parent device */
    result = acpi_bus_get_device(phandle, &pdevice);
    if (result) {
        printk(KERN_WARNING PREFIX "Cannot get acpi bus device");
        return -EINVAL;
    }

    /*
     * Now add the notified device.  This creates the acpi_device
     * and invokes .add function
     */
    result = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
    if (result) {
        printk(KERN_WARNING PREFIX "Cannot add acpi bus");
        return -EINVAL;
    }

      end:
    *mem_device = acpi_driver_data(device);
    if (!(*mem_device)) {
        printk(KERN_ERR "\n driver data not found");
        return -ENODEV;
    }

    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, "_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_memory_enable_device(struct acpi_memory_device *mem_device)
{
    int result, num_enabled = 0;
    struct acpi_memory_info *info;
    int node;


    /* Get the range from the _CRS */
    result = acpi_memory_get_device_resources(mem_device);
    if (result) {
        printk(KERN_ERR PREFIX "get_device_resources failed\n");
        mem_device->state = MEMORY_INVALID_STATE;
        return result;
    }

    node = acpi_get_node(mem_device->device->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);
        if (result)
            continue;
        info->enabled = 1;
        num_enabled++;
    }
    if (!num_enabled) {
        printk(KERN_ERR PREFIX "add_memory failed\n");
        mem_device->state = MEMORY_INVALID_STATE;
        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 int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
{
    acpi_status status;
    struct acpi_object_list arg_list;
    union acpi_object arg;
    unsigned long long current_status;


    /* Issue the _EJ0 command */
    arg_list.count = 1;
    arg_list.pointer = &arg;
    arg.type = ACPI_TYPE_INTEGER;
    arg.integer.value = 1;
    status = acpi_evaluate_object(mem_device->device->handle,
                      "_EJ0", &arg_list, NULL);
    /* Return on _EJ0 failure */
    if (ACPI_FAILURE(status)) {
        ACPI_EXCEPTION((AE_INFO, status, "_EJ0 failed"));
        return -ENODEV;
    }

    /* Evalute _STA to check if the device is disabled */
    status = acpi_evaluate_integer(mem_device->device->handle, "_STA",
                       NULL, &current_status);
    if (ACPI_FAILURE(status))
        return -ENODEV;

    /* Check for device status.  Device should be disabled */
    if (current_status & ACPI_STA_DEVICE_ENABLED)
        return -EINVAL;

    return 0;
}

static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
{
    int result;
    struct acpi_memory_info *info, *n;


    /*
     * Ask the VM to offline this memory range.
     * Note: Assume that this function returns zero on success
     */
    list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
        if (info->enabled) {
            result = remove_memory(info->start_addr, info->length);
            if (result)
                return result;
        }
        kfree(info);
    }

    /* Power-off and eject the device */
    result = acpi_memory_powerdown_device(mem_device);
    if (result) {
        /* Set the status of the device to invalid */
        mem_device->state = MEMORY_INVALID_STATE;
        return result;
    }

    mem_device->state = MEMORY_POWER_OFF_STATE;
    return result;
}

static void acpi_memory_device_notify(acpi_handle handle, u32 event, void *data)
{
    struct acpi_memory_device *mem_device;
    struct acpi_device *device;
    u32 ost_code = ACPI_OST_SC_NON_SPECIFIC_FAILURE; /* default */

    switch (event) {
    case ACPI_NOTIFY_BUS_CHECK:
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                  "\nReceived BUS CHECK notification for device\n"));
        /* Fall Through */
    case ACPI_NOTIFY_DEVICE_CHECK:
        if (event == ACPI_NOTIFY_DEVICE_CHECK)
            ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                      "\nReceived DEVICE CHECK notification for device\n"));
        if (acpi_memory_get_device(handle, &mem_device)) {
            printk(KERN_ERR PREFIX "Cannot find driver data\n");
            break;
        }

        if (acpi_memory_check_device(mem_device))
            break;

        if (acpi_memory_enable_device(mem_device)) {
            printk(KERN_ERR PREFIX "Cannot enable memory device\n");
            break;
        }

        ost_code = ACPI_OST_SC_SUCCESS;
        break;

    case ACPI_NOTIFY_EJECT_REQUEST:
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                  "\nReceived EJECT REQUEST notification for device\n"));

        if (acpi_bus_get_device(handle, &device)) {
            printk(KERN_ERR PREFIX "Device doesn't exist\n");
            break;
        }
        mem_device = acpi_driver_data(device);
        if (!mem_device) {
            printk(KERN_ERR PREFIX "Driver Data is NULL\n");
            break;
        }

        /*
         * Currently disabling memory device from kernel mode
         * TBD: Can also be disabled from user mode scripts
         * TBD: Can also be disabled by Callback registration
         *      with generic sysfs driver
         */
        if (acpi_memory_disable_device(mem_device)) {
            printk(KERN_ERR PREFIX "Disable memory device\n");
            /*
             * If _EJ0 was called but failed, _OST is not
             * necessary.
             */
            if (mem_device->state == MEMORY_INVALID_STATE)
                return;

            break;
        }

        /*
         * TBD: Invoke acpi_bus_remove to cleanup data structures
         */

        /* _EJ0 succeeded; _OST is not necessary */
        return;

    default:
        ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                  "Unsupported event [0x%x]\n", event));

        /* non-hotplug event; possibly handled by other handler */
        return;
    }

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

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


    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) {
        kfree(mem_device);
        return result;
    }

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

    printk(KERN_DEBUG "%s \n", acpi_device_name(device));

    /*
     * Early boot code has recognized memory area by EFI/E820.
     * If DSDT shows these memory devices on boot, hotplug is not necessary
     * for them. So, it just returns until completion of this driver's
     * start up.
     */
    if (!acpi_hotmem_initialized)
        return 0;

    if (!acpi_memory_check_device(mem_device)) {
        /* call add_memory func */
        result = acpi_memory_enable_device(mem_device);
        if (result)
            printk(KERN_ERR PREFIX
                "Error in acpi_memory_enable_device\n");
    }
    return result;
}

static int acpi_memory_device_remove(struct acpi_device *device, int type)
{
    struct acpi_memory_device *mem_device = NULL;


    if (!device || !acpi_driver_data(device))
        return -EINVAL;

    mem_device = acpi_driver_data(device);
    kfree(mem_device);

    return 0;
}

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

    status = acpi_get_object_info(handle, &info);
    if (ACPI_FAILURE(status))
        return status;

    if (!(info->valid & ACPI_VALID_HID)) {
        kfree(info);
        return AE_ERROR;
    }

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

    kfree(info);
    return status;
}

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


    status = is_memory_device(handle);
    if (ACPI_FAILURE(status))
        return AE_OK;   /* continue */

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

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


    status = is_memory_device(handle);
    if (ACPI_FAILURE(status))
        return AE_OK;   /* continue */

    status = acpi_remove_notify_handler(handle,
                        ACPI_SYSTEM_NOTIFY,
                        acpi_memory_device_notify);

    return AE_OK;   /* continue */
}

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


    result = acpi_bus_register_driver(&acpi_memory_device_driver);

    if (result < 0)
        return -ENODEV;

    status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
                     ACPI_UINT32_MAX,
                     acpi_memory_register_notify_handler, NULL,
                     NULL, NULL);

    if (ACPI_FAILURE(status)) {
        ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));
        acpi_bus_unregister_driver(&acpi_memory_device_driver);
        return -ENODEV;
    }

    acpi_hotmem_initialized = 1;
    return 0;
}

static void __exit acpi_memory_device_exit(void)
{
    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,
                     ACPI_UINT32_MAX,
                     acpi_memory_deregister_notify_handler, NULL,
                     NULL, NULL);

    if (ACPI_FAILURE(status))
        ACPI_EXCEPTION((AE_INFO, status, "walk_namespace failed"));

    acpi_bus_unregister_driver(&acpi_memory_device_driver);

    return;
}

module_init(acpi_memory_device_init);
module_exit(acpi_memory_device_exit);