ACPI: prevent processor module from loading on failures

[wandboard.git] / drivers / acpi / processor_core.c

/*
 * acpi_processor.c - ACPI Processor Driver ($Revision: 71 $)
 *
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 *  Copyright (C) 2004       Dominik Brodowski <linux@brodo.de>
 *  Copyright (C) 2004  Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 *                      - Added processor hotplug support
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  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.  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.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *  TBD:
 *      1. Make # power states dynamic.
 *      2. Support duty_cycle values that span bit 4.
 *      3. Optimize by having scheduler determine business instead of
 *         having us try to calculate it here.
 *      4. Need C1 timing -- must modify kernel (IRQ handler) to get this.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/pm.h>
#include <linux/cpufreq.h>
#include <linux/cpu.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/dmi.h>
#include <linux/moduleparam.h>

#include <asm/io.h>
#include <asm/system.h>
#include <asm/cpu.h>
#include <asm/delay.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <asm/smp.h>
#include <asm/acpi.h>

#include <acpi/acpi_bus.h>
#include <acpi/acpi_drivers.h>
#include <acpi/processor.h>

#define ACPI_PROCESSOR_COMPONENT        0x01000000
#define ACPI_PROCESSOR_CLASS            "processor"
#define ACPI_PROCESSOR_DRIVER_NAME      "ACPI Processor Driver"
#define ACPI_PROCESSOR_DEVICE_NAME      "Processor"
#define ACPI_PROCESSOR_FILE_INFO        "info"
#define ACPI_PROCESSOR_FILE_THROTTLING  "throttling"
#define ACPI_PROCESSOR_FILE_LIMIT       "limit"
#define ACPI_PROCESSOR_NOTIFY_PERFORMANCE 0x80
#define ACPI_PROCESSOR_NOTIFY_POWER     0x81

#define ACPI_PROCESSOR_LIMIT_USER       0
#define ACPI_PROCESSOR_LIMIT_THERMAL    1

#define ACPI_STA_PRESENT 0x00000001

#define _COMPONENT              ACPI_PROCESSOR_COMPONENT
ACPI_MODULE_NAME("acpi_processor")

    MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_DESCRIPTION(ACPI_PROCESSOR_DRIVER_NAME);
MODULE_LICENSE("GPL");

static int acpi_processor_add(struct acpi_device *device);
static int acpi_processor_start(struct acpi_device *device);
static int acpi_processor_remove(struct acpi_device *device, int type);
static int acpi_processor_info_open_fs(struct inode *inode, struct file *file);
static void acpi_processor_notify(acpi_handle handle, u32 event, void *data);
static acpi_status acpi_processor_hotadd_init(acpi_handle handle, int *p_cpu);
static int acpi_processor_handle_eject(struct acpi_processor *pr);

static struct acpi_driver acpi_processor_driver = {
        .name = ACPI_PROCESSOR_DRIVER_NAME,
        .class = ACPI_PROCESSOR_CLASS,
        .ids = ACPI_PROCESSOR_HID,
        .ops = {
                .add = acpi_processor_add,
                .remove = acpi_processor_remove,
                .start = acpi_processor_start,
                },
};

#define INSTALL_NOTIFY_HANDLER          1
#define UNINSTALL_NOTIFY_HANDLER        2

static const struct file_operations acpi_processor_info_fops = {
        .open = acpi_processor_info_open_fs,
        .read = seq_read,
        .llseek = seq_lseek,
        .release = single_release,
};

struct acpi_processor *processors[NR_CPUS];
struct acpi_processor_errata errata __read_mostly;

/* --------------------------------------------------------------------------
                                Errata Handling
   -------------------------------------------------------------------------- */

static int acpi_processor_errata_piix4(struct pci_dev *dev)
{
        u8 rev = 0;
        u8 value1 = 0;
        u8 value2 = 0;


        if (!dev)
                return -EINVAL;

        /*
         * Note that 'dev' references the PIIX4 ACPI Controller.
         */

        pci_read_config_byte(dev, PCI_REVISION_ID, &rev);

        switch (rev) {
        case 0:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 A-step\n"));
                break;
        case 1:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4 B-step\n"));
                break;
        case 2:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4E\n"));
                break;
        case 3:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found PIIX4M\n"));
                break;
        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Found unknown PIIX4\n"));
                break;
        }

        switch (rev) {

        case 0:         /* PIIX4 A-step */
        case 1:         /* PIIX4 B-step */
                /*
                 * See specification changes #13 ("Manual Throttle Duty Cycle")
                 * and #14 ("Enabling and Disabling Manual Throttle"), plus
                 * erratum #5 ("STPCLK# Deassertion Time") from the January
                 * 2002 PIIX4 specification update.  Applies to only older
                 * PIIX4 models.
                 */
                errata.piix4.throttle = 1;

        case 2:         /* PIIX4E */
        case 3:         /* PIIX4M */
                /*
                 * See erratum #18 ("C3 Power State/BMIDE and Type-F DMA
                 * Livelock") from the January 2002 PIIX4 specification update.
                 * Applies to all PIIX4 models.
                 */

                /*
                 * BM-IDE
                 * ------
                 * Find the PIIX4 IDE Controller and get the Bus Master IDE
                 * Status register address.  We'll use this later to read
                 * each IDE controller's DMA status to make sure we catch all
                 * DMA activity.
                 */
                dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
                                     PCI_DEVICE_ID_INTEL_82371AB,
                                     PCI_ANY_ID, PCI_ANY_ID, NULL);
                if (dev) {
                        errata.piix4.bmisx = pci_resource_start(dev, 4);
                        pci_dev_put(dev);
                }

                /*
                 * Type-F DMA
                 * ----------
                 * Find the PIIX4 ISA Controller and read the Motherboard
                 * DMA controller's status to see if Type-F (Fast) DMA mode
                 * is enabled (bit 7) on either channel.  Note that we'll
                 * disable C3 support if this is enabled, as some legacy
                 * devices won't operate well if fast DMA is disabled.
                 */
                dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
                                     PCI_DEVICE_ID_INTEL_82371AB_0,
                                     PCI_ANY_ID, PCI_ANY_ID, NULL);
                if (dev) {
                        pci_read_config_byte(dev, 0x76, &value1);
                        pci_read_config_byte(dev, 0x77, &value2);
                        if ((value1 & 0x80) || (value2 & 0x80))
                                errata.piix4.fdma = 1;
                        pci_dev_put(dev);
                }

                break;
        }

        if (errata.piix4.bmisx)
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Bus master activity detection (BM-IDE) erratum enabled\n"));
        if (errata.piix4.fdma)
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Type-F DMA livelock erratum (C3 disabled)\n"));

        return 0;
}

static int acpi_processor_errata(struct acpi_processor *pr)
{
        int result = 0;
        struct pci_dev *dev = NULL;


        if (!pr)
                return -EINVAL;

        /*
         * PIIX4
         */
        dev = pci_get_subsys(PCI_VENDOR_ID_INTEL,
                             PCI_DEVICE_ID_INTEL_82371AB_3, PCI_ANY_ID,
                             PCI_ANY_ID, NULL);
        if (dev) {
                result = acpi_processor_errata_piix4(dev);
                pci_dev_put(dev);
        }

        return result;
}

/* --------------------------------------------------------------------------
                              Common ACPI processor functions
   -------------------------------------------------------------------------- */

/*
 * _PDC is required for a BIOS-OS handshake for most of the newer
 * ACPI processor features.
 */
static int acpi_processor_set_pdc(struct acpi_processor *pr)
{
        struct acpi_object_list *pdc_in = pr->pdc;
        acpi_status status = AE_OK;


        if (!pdc_in)
                return status;

        status = acpi_evaluate_object(pr->handle, "_PDC", pdc_in, NULL);

        if (ACPI_FAILURE(status))
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                    "Could not evaluate _PDC, using legacy perf. control...\n"));

        return status;
}

/* --------------------------------------------------------------------------
                              FS Interface (/proc)
   -------------------------------------------------------------------------- */

static struct proc_dir_entry *acpi_processor_dir = NULL;

static int acpi_processor_info_seq_show(struct seq_file *seq, void *offset)
{
        struct acpi_processor *pr = (struct acpi_processor *)seq->private;


        if (!pr)
                goto end;

        seq_printf(seq, "processor id:            %d\n"
                   "acpi id:                 %d\n"
                   "bus mastering control:   %s\n"
                   "power management:        %s\n"
                   "throttling control:      %s\n"
                   "limit interface:         %s\n",
                   pr->id,
                   pr->acpi_id,
                   pr->flags.bm_control ? "yes" : "no",
                   pr->flags.power ? "yes" : "no",
                   pr->flags.throttling ? "yes" : "no",
                   pr->flags.limit ? "yes" : "no");

      end:
        return 0;
}

static int acpi_processor_info_open_fs(struct inode *inode, struct file *file)
{
        return single_open(file, acpi_processor_info_seq_show,
                           PDE(inode)->data);
}

static int acpi_processor_add_fs(struct acpi_device *device)
{
        struct proc_dir_entry *entry = NULL;


        if (!acpi_device_dir(device)) {
                acpi_device_dir(device) = proc_mkdir(acpi_device_bid(device),
                                                     acpi_processor_dir);
                if (!acpi_device_dir(device))
                        return -ENODEV;
        }
        acpi_device_dir(device)->owner = THIS_MODULE;

        /* 'info' [R] */
        entry = create_proc_entry(ACPI_PROCESSOR_FILE_INFO,
                                  S_IRUGO, acpi_device_dir(device));
        if (!entry)
                return -EIO;
        else {
                entry->proc_fops = &acpi_processor_info_fops;
                entry->data = acpi_driver_data(device);
                entry->owner = THIS_MODULE;
        }

        /* 'throttling' [R/W] */
        entry = create_proc_entry(ACPI_PROCESSOR_FILE_THROTTLING,
                                  S_IFREG | S_IRUGO | S_IWUSR,
                                  acpi_device_dir(device));
        if (!entry)
                return -EIO;
        else {
                entry->proc_fops = &acpi_processor_throttling_fops;
                entry->data = acpi_driver_data(device);
                entry->owner = THIS_MODULE;
        }

        /* 'limit' [R/W] */
        entry = create_proc_entry(ACPI_PROCESSOR_FILE_LIMIT,
                                  S_IFREG | S_IRUGO | S_IWUSR,
                                  acpi_device_dir(device));
        if (!entry)
                return -EIO;
        else {
                entry->proc_fops = &acpi_processor_limit_fops;
                entry->data = acpi_driver_data(device);
                entry->owner = THIS_MODULE;
        }

        return 0;
}

static int acpi_processor_remove_fs(struct acpi_device *device)
{

        if (acpi_device_dir(device)) {
                remove_proc_entry(ACPI_PROCESSOR_FILE_INFO,
                                  acpi_device_dir(device));
                remove_proc_entry(ACPI_PROCESSOR_FILE_THROTTLING,
                                  acpi_device_dir(device));
                remove_proc_entry(ACPI_PROCESSOR_FILE_LIMIT,
                                  acpi_device_dir(device));
                remove_proc_entry(acpi_device_bid(device), acpi_processor_dir);
                acpi_device_dir(device) = NULL;
        }

        return 0;
}

/* Use the acpiid in MADT to map cpus in case of SMP */
#ifndef CONFIG_SMP
#define convert_acpiid_to_cpu(acpi_id) (-1)
#else

#ifdef CONFIG_IA64
#define arch_acpiid_to_apicid   ia64_acpiid_to_sapicid
#define arch_cpu_to_apicid      ia64_cpu_to_sapicid
#define ARCH_BAD_APICID         (0xffff)
#else
#define arch_acpiid_to_apicid   x86_acpiid_to_apicid
#define arch_cpu_to_apicid      x86_cpu_to_apicid
#define ARCH_BAD_APICID         (0xff)
#endif

static int convert_acpiid_to_cpu(u8 acpi_id)
{
        u16 apic_id;
        int i;

        apic_id = arch_acpiid_to_apicid[acpi_id];
        if (apic_id == ARCH_BAD_APICID)
                return -1;

        for (i = 0; i < NR_CPUS; i++) {
                if (arch_cpu_to_apicid[i] == apic_id)
                        return i;
        }
        return -1;
}
#endif

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */

static int acpi_processor_get_info(struct acpi_processor *pr)
{
        acpi_status status = 0;
        union acpi_object object = { 0 };
        struct acpi_buffer buffer = { sizeof(union acpi_object), &object };
        int cpu_index;
        static int cpu0_initialized;


        if (!pr)
                return -EINVAL;

        if (num_online_cpus() > 1)
                errata.smp = TRUE;

        acpi_processor_errata(pr);

        /*
         * Check to see if we have bus mastering arbitration control.  This
         * is required for proper C3 usage (to maintain cache coherency).
         */
        if (acpi_fadt.V1_pm2_cnt_blk && acpi_fadt.pm2_cnt_len) {
                pr->flags.bm_control = 1;
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Bus mastering arbitration control present\n"));
        } else
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "No bus mastering arbitration control\n"));

        /*
         * Evalute the processor object.  Note that it is common on SMP to
         * have the first (boot) processor with a valid PBLK address while
         * all others have a NULL address.
         */
        status = acpi_evaluate_object(pr->handle, NULL, NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                printk(KERN_ERR PREFIX "Evaluating processor object\n");
                return -ENODEV;
        }

        /*
         * TBD: Synch processor ID (via LAPIC/LSAPIC structures) on SMP.
         *      >>> 'acpi_get_processor_id(acpi_id, &id)' in arch/xxx/acpi.c
         */
        pr->acpi_id = object.processor.proc_id;

        cpu_index = convert_acpiid_to_cpu(pr->acpi_id);

        /* Handle UP system running SMP kernel, with no LAPIC in MADT */
        if (!cpu0_initialized && (cpu_index == -1) &&
            (num_online_cpus() == 1)) {
                cpu_index = 0;
        }

        cpu0_initialized = 1;

        pr->id = cpu_index;

        /*
         *  Extra Processor objects may be enumerated on MP systems with
         *  less than the max # of CPUs. They should be ignored _iff
         *  they are physically not present.
         */
        if (cpu_index == -1) {
                if (ACPI_FAILURE
                    (acpi_processor_hotadd_init(pr->handle, &pr->id))) {
                        printk(KERN_ERR PREFIX
                                    "Getting cpuindex for acpiid 0x%x\n",
                                    pr->acpi_id);
                        return -ENODEV;
                }
        }

        ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Processor [%d:%d]\n", pr->id,
                          pr->acpi_id));

        if (!object.processor.pblk_address)
                ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No PBLK (NULL address)\n"));
        else if (object.processor.pblk_length != 6)
                printk(KERN_ERR PREFIX "Invalid PBLK length [%d]\n",
                            object.processor.pblk_length);
        else {
                pr->throttling.address = object.processor.pblk_address;
                pr->throttling.duty_offset = acpi_fadt.duty_offset;
                pr->throttling.duty_width = acpi_fadt.duty_width;

                pr->pblk = object.processor.pblk_address;

                /*
                 * We don't care about error returns - we just try to mark
                 * these reserved so that nobody else is confused into thinking
                 * that this region might be unused..
                 *
                 * (In particular, allocating the IO range for Cardbus)
                 */
                request_region(pr->throttling.address, 6, "ACPI CPU throttle");
        }

#ifdef CONFIG_CPU_FREQ
        acpi_processor_ppc_has_changed(pr);
#endif
        acpi_processor_get_throttling_info(pr);
        acpi_processor_get_limit_info(pr);

        return 0;
}

static void *processor_device_array[NR_CPUS];

static int __cpuinit acpi_processor_start(struct acpi_device *device)
{
        int result = 0;
        acpi_status status = AE_OK;
        struct acpi_processor *pr;


        pr = acpi_driver_data(device);

        result = acpi_processor_get_info(pr);
        if (result) {
                /* Processor is physically not present */
                return 0;
        }

        BUG_ON((pr->id >= NR_CPUS) || (pr->id < 0));

        /*
         * Buggy BIOS check
         * ACPI id of processors can be reported wrongly by the BIOS.
         * Don't trust it blindly
         */
        if (processor_device_array[pr->id] != NULL &&
            processor_device_array[pr->id] != (void *)device) {
                printk(KERN_WARNING "BIOS reported wrong ACPI id"
                        "for the processor\n");
                return -ENODEV;
        }
        processor_device_array[pr->id] = (void *)device;

        processors[pr->id] = pr;

        result = acpi_processor_add_fs(device);
        if (result)
                goto end;

        status = acpi_install_notify_handler(pr->handle, ACPI_DEVICE_NOTIFY,
                                             acpi_processor_notify, pr);

        /* _PDC call should be done before doing anything else (if reqd.). */
        arch_acpi_processor_init_pdc(pr);
        acpi_processor_set_pdc(pr);

        acpi_processor_power_init(pr, device);

        if (pr->flags.throttling) {
                printk(KERN_INFO PREFIX "%s [%s] (supports",
                       acpi_device_name(device), acpi_device_bid(device));
                printk(" %d throttling states", pr->throttling.state_count);
                printk(")\n");
        }

      end:

        return result;
}

static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_processor *pr = (struct acpi_processor *)data;
        struct acpi_device *device = NULL;


        if (!pr)
                return;

        if (acpi_bus_get_device(pr->handle, &device))
                return;

        switch (event) {
        case ACPI_PROCESSOR_NOTIFY_PERFORMANCE:
                acpi_processor_ppc_has_changed(pr);
                acpi_bus_generate_event(device, event,
                                        pr->performance_platform_limit);
                break;
        case ACPI_PROCESSOR_NOTIFY_POWER:
                acpi_processor_cst_has_changed(pr);
                acpi_bus_generate_event(device, event, 0);
                break;
        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Unsupported event [0x%x]\n", event));
                break;
        }

        return;
}

static int acpi_processor_add(struct acpi_device *device)
{
        struct acpi_processor *pr = NULL;


        if (!device)
                return -EINVAL;

        pr = kmalloc(sizeof(struct acpi_processor), GFP_KERNEL);
        if (!pr)
                return -ENOMEM;
        memset(pr, 0, sizeof(struct acpi_processor));

        pr->handle = device->handle;
        strcpy(acpi_device_name(device), ACPI_PROCESSOR_DEVICE_NAME);
        strcpy(acpi_device_class(device), ACPI_PROCESSOR_CLASS);
        acpi_driver_data(device) = pr;

        return 0;
}

static int acpi_processor_remove(struct acpi_device *device, int type)
{
        acpi_status status = AE_OK;
        struct acpi_processor *pr = NULL;


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

        pr = (struct acpi_processor *)acpi_driver_data(device);

        if (pr->id >= NR_CPUS) {
                kfree(pr);
                return 0;
        }

        if (type == ACPI_BUS_REMOVAL_EJECT) {
                if (acpi_processor_handle_eject(pr))
                        return -EINVAL;
        }

        acpi_processor_power_exit(pr, device);

        status = acpi_remove_notify_handler(pr->handle, ACPI_DEVICE_NOTIFY,
                                            acpi_processor_notify);

        acpi_processor_remove_fs(device);

        processors[pr->id] = NULL;

        kfree(pr);

        return 0;
}

#ifdef CONFIG_ACPI_HOTPLUG_CPU
/****************************************************************************
 *      Acpi processor hotplug support                                      *
 ****************************************************************************/

static int is_processor_present(acpi_handle handle);

static int is_processor_present(acpi_handle handle)
{
        acpi_status status;
        unsigned long sta = 0;


        status = acpi_evaluate_integer(handle, "_STA", NULL, &sta);
        if (ACPI_FAILURE(status) || !(sta & ACPI_STA_PRESENT)) {
                ACPI_EXCEPTION((AE_INFO, status, "Processor Device is not present"));
                return 0;
        }
        return 1;
}

static
int acpi_processor_device_add(acpi_handle handle, struct acpi_device **device)
{
        acpi_handle phandle;
        struct acpi_device *pdev;
        struct acpi_processor *pr;


        if (acpi_get_parent(handle, &phandle)) {
                return -ENODEV;
        }

        if (acpi_bus_get_device(phandle, &pdev)) {
                return -ENODEV;
        }

        if (acpi_bus_add(device, pdev, handle, ACPI_BUS_TYPE_PROCESSOR)) {
                return -ENODEV;
        }

        acpi_bus_start(*device);

        pr = acpi_driver_data(*device);
        if (!pr)
                return -ENODEV;

        if ((pr->id >= 0) && (pr->id < NR_CPUS)) {
                kobject_uevent(&(*device)->kobj, KOBJ_ONLINE);
        }
        return 0;
}

static void
acpi_processor_hotplug_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_processor *pr;
        struct acpi_device *device = NULL;
        int result;


        switch (event) {
        case ACPI_NOTIFY_BUS_CHECK:
        case ACPI_NOTIFY_DEVICE_CHECK:
                printk("Processor driver received %s event\n",
                       (event == ACPI_NOTIFY_BUS_CHECK) ?
                       "ACPI_NOTIFY_BUS_CHECK" : "ACPI_NOTIFY_DEVICE_CHECK");

                if (!is_processor_present(handle))
                        break;

                if (acpi_bus_get_device(handle, &device)) {
                        result = acpi_processor_device_add(handle, &device);
                        if (result)
                                printk(KERN_ERR PREFIX
                                            "Unable to add the device\n");
                        break;
                }

                pr = acpi_driver_data(device);
                if (!pr) {
                        printk(KERN_ERR PREFIX "Driver data is NULL\n");
                        break;
                }

                if (pr->id >= 0 && (pr->id < NR_CPUS)) {
                        kobject_uevent(&device->kobj, KOBJ_OFFLINE);
                        break;
                }

                result = acpi_processor_start(device);
                if ((!result) && ((pr->id >= 0) && (pr->id < NR_CPUS))) {
                        kobject_uevent(&device->kobj, KOBJ_ONLINE);
                } else {
                        printk(KERN_ERR PREFIX "Device [%s] failed to start\n",
                                    acpi_device_bid(device));
                }
                break;
        case ACPI_NOTIFY_EJECT_REQUEST:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "received ACPI_NOTIFY_EJECT_REQUEST\n"));

                if (acpi_bus_get_device(handle, &device)) {
                        printk(KERN_ERR PREFIX
                                    "Device don't exist, dropping EJECT\n");
                        break;
                }
                pr = acpi_driver_data(device);
                if (!pr) {
                        printk(KERN_ERR PREFIX
                                    "Driver data is NULL, dropping EJECT\n");
                        return;
                }

                if ((pr->id < NR_CPUS) && (cpu_present(pr->id)))
                        kobject_uevent(&device->kobj, KOBJ_OFFLINE);
                break;
        default:
                ACPI_DEBUG_PRINT((ACPI_DB_INFO,
                                  "Unsupported event [0x%x]\n", event));
                break;
        }

        return;
}

static acpi_status
processor_walk_namespace_cb(acpi_handle handle,
                            u32 lvl, void *context, void **rv)
{
        acpi_status status;
        int *action = context;
        acpi_object_type type = 0;

        status = acpi_get_type(handle, &type);
        if (ACPI_FAILURE(status))
                return (AE_OK);

        if (type != ACPI_TYPE_PROCESSOR)
                return (AE_OK);

        switch (*action) {
        case INSTALL_NOTIFY_HANDLER:
                acpi_install_notify_handler(handle,
                                            ACPI_SYSTEM_NOTIFY,
                                            acpi_processor_hotplug_notify,
                                            NULL);
                break;
        case UNINSTALL_NOTIFY_HANDLER:
                acpi_remove_notify_handler(handle,
                                           ACPI_SYSTEM_NOTIFY,
                                           acpi_processor_hotplug_notify);
                break;
        default:
                break;
        }

        return (AE_OK);
}

static acpi_status acpi_processor_hotadd_init(acpi_handle handle, int *p_cpu)
{

        if (!is_processor_present(handle)) {
                return AE_ERROR;
        }

        if (acpi_map_lsapic(handle, p_cpu))
                return AE_ERROR;

        if (arch_register_cpu(*p_cpu)) {
                acpi_unmap_lsapic(*p_cpu);
                return AE_ERROR;
        }

        return AE_OK;
}

static int acpi_processor_handle_eject(struct acpi_processor *pr)
{
        if (cpu_online(pr->id)) {
                return (-EINVAL);
        }
        arch_unregister_cpu(pr->id);
        acpi_unmap_lsapic(pr->id);
        return (0);
}
#else
static acpi_status acpi_processor_hotadd_init(acpi_handle handle, int *p_cpu)
{
        return AE_ERROR;
}
static int acpi_processor_handle_eject(struct acpi_processor *pr)
{
        return (-EINVAL);
}
#endif

static
void acpi_processor_install_hotplug_notify(void)
{
#ifdef CONFIG_ACPI_HOTPLUG_CPU
        int action = INSTALL_NOTIFY_HANDLER;
        acpi_walk_namespace(ACPI_TYPE_PROCESSOR,
                            ACPI_ROOT_OBJECT,
                            ACPI_UINT32_MAX,
                            processor_walk_namespace_cb, &action, NULL);
#endif
}

static
void acpi_processor_uninstall_hotplug_notify(void)
{
#ifdef CONFIG_ACPI_HOTPLUG_CPU
        int action = UNINSTALL_NOTIFY_HANDLER;
        acpi_walk_namespace(ACPI_TYPE_PROCESSOR,
                            ACPI_ROOT_OBJECT,
                            ACPI_UINT32_MAX,
                            processor_walk_namespace_cb, &action, NULL);
#endif
}

/*
 * We keep the driver loaded even when ACPI is not running.
 * This is needed for the powernow-k8 driver, that works even without
 * ACPI, but needs symbols from this driver
 */

static int __init acpi_processor_init(void)
{
        int result = 0;


        memset(&processors, 0, sizeof(processors));
        memset(&errata, 0, sizeof(errata));

        acpi_processor_dir = proc_mkdir(ACPI_PROCESSOR_CLASS, acpi_root_dir);
        if (!acpi_processor_dir)
                return -ENOMEM;
        acpi_processor_dir->owner = THIS_MODULE;

        result = acpi_bus_register_driver(&acpi_processor_driver);
        if (result < 0) {
                remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir);
                return result;
        }

        acpi_processor_install_hotplug_notify();

        acpi_thermal_cpufreq_init();

        acpi_processor_ppc_init();

        return 0;
}

static void __exit acpi_processor_exit(void)
{

        acpi_processor_ppc_exit();

        acpi_thermal_cpufreq_exit();

        acpi_processor_uninstall_hotplug_notify();

        acpi_bus_unregister_driver(&acpi_processor_driver);

        remove_proc_entry(ACPI_PROCESSOR_CLASS, acpi_root_dir);

        return;
}

module_init(acpi_processor_init);
module_exit(acpi_processor_exit);

EXPORT_SYMBOL(acpi_processor_set_thermal_limit);

MODULE_ALIAS("processor");