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/*

 * drivers/base/memory.c - basic Memory class support

 *

 * Written by Matt Tolentino <matthew.e.tolentino@intel.com>

 *            Dave Hansen <haveblue@us.ibm.com>

 *

 * This file provides the necessary infrastructure to represent

 * a SPARSEMEM-memory-model system's physical memory in /sysfs.

 * All arch-independent code that assumes MEMORY_HOTPLUG requires

 * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.

 */

#include <linux/sysdev.h>

#include <linux/module.h>

#include <linux/init.h>

#include <linux/topology.h>

#include <linux/capability.h>

#include <linux/device.h>

#include <linux/memory.h>

#include <linux/kobject.h>

#include <linux/memory_hotplug.h>

#include <linux/mm.h>

#include <asm/atomic.h>

#include <asm/uaccess.h>

#define MEMORY_CLASS_NAME       "memory"

static struct sysdev_class memory_sysdev_class = {

        set_kset_name(MEMORY_CLASS_NAME),

};

static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)

{

        return MEMORY_CLASS_NAME;

}

static int memory_uevent(struct kset *kset, struct kobject *obj, struct kobj_uevent_env *env)

{

        int retval = 0;

        return retval;

}

static struct kset_uevent_ops memory_uevent_ops = {

        .name           = memory_uevent_name,

        .uevent         = memory_uevent,

};

static BLOCKING_NOTIFIER_HEAD(memory_chain);

int register_memory_notifier(struct notifier_block *nb)

{

        return blocking_notifier_chain_register(&memory_chain, nb);

}

void unregister_memory_notifier(struct notifier_block *nb)

{

        blocking_notifier_chain_unregister(&memory_chain, nb);

}

/*

 * register_memory - Setup a sysfs device for a memory block

 */

int register_memory(struct memory_block *memory, struct mem_section *section,

                struct node *root)

{

        int error;

        memory->sysdev.cls = &memory_sysdev_class;

        memory->sysdev.id = __section_nr(section);

        error = sysdev_register(&memory->sysdev);

        if (root && !error)

                error = sysfs_create_link(&root->sysdev.kobj,

                                          &memory->sysdev.kobj,

                                          kobject_name(&memory->sysdev.kobj));

        return error;

}

static void

unregister_memory(struct memory_block *memory, struct mem_section *section,

                struct node *root)

{

        BUG_ON(memory->sysdev.cls != &memory_sysdev_class);

        BUG_ON(memory->sysdev.id != __section_nr(section));

        sysdev_unregister(&memory->sysdev);

        if (root)

                sysfs_remove_link(&root->sysdev.kobj,

                                  kobject_name(&memory->sysdev.kobj));

}

/*

 * use this as the physical section index that this memsection

 * uses.

 */

static ssize_t show_mem_phys_index(struct sys_device *dev, char *buf)

{

        struct memory_block *mem =

                container_of(dev, struct memory_block, sysdev);

        return sprintf(buf, "%08lx\n", mem->phys_index);

}

/*

 * online, offline, going offline, etc.

 */

static ssize_t show_mem_state(struct sys_device *dev, char *buf)

{

        struct memory_block *mem =

                container_of(dev, struct memory_block, sysdev);

        ssize_t len = 0;

        /*

         * We can probably put these states in a nice little array

         * so that they're not open-coded

         */

        switch (mem->state) {

                case MEM_ONLINE:

                        len = sprintf(buf, "online\n");

                        break;

                case MEM_OFFLINE:

                        len = sprintf(buf, "offline\n");

                        break;

                case MEM_GOING_OFFLINE:

                        len = sprintf(buf, "going-offline\n");

                        break;

                default:

                        len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",

                                        mem->state);

                        WARN_ON(1);

                        break;

        }

        return len;

}

int memory_notify(unsigned long val, void *v)

{

        return blocking_notifier_call_chain(&memory_chain, val, v);

}

/*

 * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is

 * OK to have direct references to sparsemem variables in here.

 */

static int

memory_block_action(struct memory_block *mem, unsigned long action)

{

        int i;

        unsigned long psection;

        unsigned long start_pfn, start_paddr;

        struct page *first_page;

        int ret;

        int old_state = mem->state;

        psection = mem->phys_index;

        first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);

        /*

         * The probe routines leave the pages reserved, just

         * as the bootmem code does.  Make sure they're still

         * that way.

         */

        if (action == MEM_ONLINE) {

                for (i = 0; i < PAGES_PER_SECTION; i++) {

                        if (PageReserved(first_page+i))

                                continue;

                        printk(KERN_WARNING "section number %ld page number %d "

                                "not reserved, was it already online? \n",

                                psection, i);

                        return -EBUSY;

                }

        }

        switch (action) {

                case MEM_ONLINE:

                        start_pfn = page_to_pfn(first_page);

                        ret = online_pages(start_pfn, PAGES_PER_SECTION);

                        break;

                case MEM_OFFLINE:

                        mem->state = MEM_GOING_OFFLINE;

                        start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;

                        ret = remove_memory(start_paddr,

                                            PAGES_PER_SECTION << PAGE_SHIFT);

                        if (ret) {

                                mem->state = old_state;

                                break;

                        }

                        break;

                default:

                        printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",

                                        __FUNCTION__, mem, action, action);

                        WARN_ON(1);

                        ret = -EINVAL;

        }

        return ret;

}

static int memory_block_change_state(struct memory_block *mem,

                unsigned long to_state, unsigned long from_state_req)

{

        int ret = 0;

        down(&mem->state_sem);

        if (mem->state != from_state_req) {

                ret = -EINVAL;

                goto out;

        }

        ret = memory_block_action(mem, to_state);

        if (!ret)

                mem->state = to_state;

out:

        up(&mem->state_sem);

        return ret;

}

static ssize_t

store_mem_state(struct sys_device *dev, const char *buf, size_t count)

{

        struct memory_block *mem;

        unsigned int phys_section_nr;

        int ret = -EINVAL;

        mem = container_of(dev, struct memory_block, sysdev);

        phys_section_nr = mem->phys_index;

        if (!present_section_nr(phys_section_nr))

                goto out;

        if (!strncmp(buf, "online", min((int)count, 6)))

                ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);

        else if(!strncmp(buf, "offline", min((int)count, 7)))

                ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);

out:

        if (ret)

                return ret;

        return count;

}

/*

 * phys_device is a bad name for this.  What I really want

 * is a way to differentiate between memory ranges that

 * are part of physical devices that constitute

 * a complete removable unit or fru.

 * i.e. do these ranges belong to the same physical device,

 * s.t. if I offline all of these sections I can then

 * remove the physical device?

 */

static ssize_t show_phys_device(struct sys_device *dev, char *buf)

{

        struct memory_block *mem =

                container_of(dev, struct memory_block, sysdev);

        return sprintf(buf, "%d\n", mem->phys_device);

}

static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);

static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);

static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);

#define mem_create_simple_file(mem, attr_name)  \

        sysdev_create_file(&mem->sysdev, &attr_##attr_name)

#define mem_remove_simple_file(mem, attr_name)  \

        sysdev_remove_file(&mem->sysdev, &attr_##attr_name)

/*

 * Block size attribute stuff

 */

static ssize_t

print_block_size(struct class *class, char *buf)

{

        return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);

}

static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);

static int block_size_init(void)

{

        return sysfs_create_file(&memory_sysdev_class.kset.kobj,

                                &class_attr_block_size_bytes.attr);

}

/*

 * Some architectures will have custom drivers to do this, and

 * will not need to do it from userspace.  The fake hot-add code

 * as well as ppc64 will do all of their discovery in userspace

 * and will require this interface.

 */

#ifdef CONFIG_ARCH_MEMORY_PROBE

static ssize_t

memory_probe_store(struct class *class, const char *buf, size_t count)

{

        u64 phys_addr;

        int nid;

        int ret;

        phys_addr = simple_strtoull(buf, NULL, 0);

        nid = memory_add_physaddr_to_nid(phys_addr);

        ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);

        if (ret)

                count = ret;

        return count;

}

static CLASS_ATTR(probe, 0700, NULL, memory_probe_store);

static int memory_probe_init(void)

{

        return sysfs_create_file(&memory_sysdev_class.kset.kobj,

                                &class_attr_probe.attr);

}

#else

static inline int memory_probe_init(void)

{

        return 0;

}

#endif

/*

 * Note that phys_device is optional.  It is here to allow for

 * differentiation between which *physical* devices each

 * section belongs to...

 */

static int add_memory_block(unsigned long node_id, struct mem_section *section,

                     unsigned long state, int phys_device)

{

        struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);

        int ret = 0;

        if (!mem)

                return -ENOMEM;

        mem->phys_index = __section_nr(section);

        mem->state = state;

        init_MUTEX(&mem->state_sem);

        mem->phys_device = phys_device;

        ret = register_memory(mem, section, NULL);

        if (!ret)

                ret = mem_create_simple_file(mem, phys_index);

        if (!ret)

                ret = mem_create_simple_file(mem, state);

        if (!ret)

                ret = mem_create_simple_file(mem, phys_device);

        return ret;

}

/*

 * For now, we have a linear search to go find the appropriate

 * memory_block corresponding to a particular phys_index. If

 * this gets to be a real problem, we can always use a radix

 * tree or something here.

 *

 * This could be made generic for all sysdev classes.

 */

static struct memory_block *find_memory_block(struct mem_section *section)

{

        struct kobject *kobj;

        struct sys_device *sysdev;

        struct memory_block *mem;

        char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];

        /*

         * This only works because we know that section == sysdev->id

         * slightly redundant with sysdev_register()

         */

        sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));

        kobj = kset_find_obj(&memory_sysdev_class.kset, name);

        if (!kobj)

                return NULL;

        sysdev = container_of(kobj, struct sys_device, kobj);

        mem = container_of(sysdev, struct memory_block, sysdev);

        return mem;

}

int remove_memory_block(unsigned long node_id, struct mem_section *section,

                int phys_device)

{

        struct memory_block *mem;

        mem = find_memory_block(section);

        mem_remove_simple_file(mem, phys_index);

        mem_remove_simple_file(mem, state);

        mem_remove_simple_file(mem, phys_device);

        unregister_memory(mem, section, NULL);

        return 0;

}

/*

 * need an interface for the VM to add new memory regions,

 * but without onlining it.

 */

int register_new_memory(struct mem_section *section)

{

        return add_memory_block(0, section, MEM_OFFLINE, 0);

}

int unregister_memory_section(struct mem_section *section)

{

        if (!present_section(section))

                return -EINVAL;

        return remove_memory_block(0, section, 0);

}

/*

 * Initialize the sysfs support for memory devices...

 */

int __init memory_dev_init(void)

{

        unsigned int i;

        int ret;

        int err;

        memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;

        ret = sysdev_class_register(&memory_sysdev_class);

        if (ret)

                goto out;

        /*

         * Create entries for memory sections that were found

         * during boot and have been initialized

         */

        for (i = 0; i < NR_MEM_SECTIONS; i++) {

                if (!present_section_nr(i))

                        continue;

                err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);

                if (!ret)

                        ret = err;

        }

        err = memory_probe_init();

        if (!ret)

                ret = err;

        err = block_size_init();

        if (!ret)

                ret = err;

out:

        if (ret)

                printk(KERN_ERR "%s() failed: %d\n", __FUNCTION__, ret);

        return ret;

}