/* mdesc.c: Sun4V machine description handling.
 *
 * Copyright (C) 2007, 2008 David S. Miller <davem@davemloft.net>
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/memblock.h>
#include <linux/log2.h>
#include <linux/list.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/miscdevice.h>
#include <linux/bootmem.h>
#include <linux/export.h>

#include <asm/cpudata.h>
#include <asm/hypervisor.h>
#include <asm/mdesc.h>
#include <asm/prom.h>
#include <asm/uaccess.h>
#include <asm/oplib.h>
#include <asm/smp.h>

/* Unlike the OBP device tree, the machine description is a full-on
 * DAG.  An arbitrary number of ARCs are possible from one
 * node to other nodes and thus we can't use the OBP device_node
 * data structure to represent these nodes inside of the kernel.
 *
 * Actually, it isn't even a DAG, because there are back pointers
 * which create cycles in the graph.
 *
 * mdesc_hdr and mdesc_elem describe the layout of the data structure
 * we get from the Hypervisor.
 */
struct mdesc_hdr {
        u32     version; /* Transport version */
        u32     node_sz; /* node block size */
        u32     name_sz; /* name block size */
        u32     data_sz; /* data block size */
} __attribute__((aligned(16)));

struct mdesc_elem {
        u8      tag;
#define MD_LIST_END     0x00
#define MD_NODE         0x4e
#define MD_NODE_END     0x45
#define MD_NOOP         0x20
#define MD_PROP_ARC     0x61
#define MD_PROP_VAL     0x76
#define MD_PROP_STR     0x73
#define MD_PROP_DATA    0x64
        u8      name_len;
        u16     resv;
        u32     name_offset;
        union {
                struct {
                        u32     data_len;
                        u32     data_offset;
                } data;
                u64     val;
        } d;
};

struct mdesc_mem_ops {
        struct mdesc_handle *(*alloc)(unsigned int mdesc_size);
        void (*free)(struct mdesc_handle *handle);
};

struct mdesc_handle {
        struct list_head        list;
        struct mdesc_mem_ops    *mops;
        void                    *self_base;
        atomic_t                refcnt;
        unsigned int            handle_size;
        struct mdesc_hdr        mdesc;
};

static void mdesc_handle_init(struct mdesc_handle *hp,
                              unsigned int handle_size,
                              void *base)
{
        BUG_ON(((unsigned long)&hp->mdesc) & (16UL - 1));

        memset(hp, 0, handle_size);
        INIT_LIST_HEAD(&hp->list);
        hp->self_base = base;
        atomic_set(&hp->refcnt, 1);
        hp->handle_size = handle_size;
}

static struct mdesc_handle * __init mdesc_memblock_alloc(unsigned int mdesc_size)
{
        unsigned int handle_size, alloc_size;
        struct mdesc_handle *hp;
        unsigned long paddr;

        handle_size = (sizeof(struct mdesc_handle) -
                       sizeof(struct mdesc_hdr) +
                       mdesc_size);
        alloc_size = PAGE_ALIGN(handle_size);

        paddr = memblock_alloc(alloc_size, PAGE_SIZE);

        hp = NULL;
        if (paddr) {
                hp = __va(paddr);
                mdesc_handle_init(hp, handle_size, hp);
        }
        return hp;
}

static void __init mdesc_memblock_free(struct mdesc_handle *hp)
{
        unsigned int alloc_size;
        unsigned long start;

        BUG_ON(atomic_read(&hp->refcnt) != 0);
        BUG_ON(!list_empty(&hp->list));

        alloc_size = PAGE_ALIGN(hp->handle_size);
        start = __pa(hp);
        free_bootmem_late(start, alloc_size);
}

static struct mdesc_mem_ops memblock_mdesc_ops = {
        .alloc = mdesc_memblock_alloc,
        .free  = mdesc_memblock_free,
};

static struct mdesc_handle *mdesc_kmalloc(unsigned int mdesc_size)
{
        unsigned int handle_size;
        struct mdesc_handle *hp;
        unsigned long addr;
        void *base;

        handle_size = (sizeof(struct mdesc_handle) -
                       sizeof(struct mdesc_hdr) +
                       mdesc_size);

        /*
         * Allocation has to succeed because mdesc update would be missed
         * and such events are not retransmitted.
         */
        base = kmalloc(handle_size + 15, GFP_KERNEL | __GFP_NOFAIL);
        addr = (unsigned long)base;
        addr = (addr + 15UL) & ~15UL;
        hp = (struct mdesc_handle *) addr;

        mdesc_handle_init(hp, handle_size, base);

        return hp;
}

static void mdesc_kfree(struct mdesc_handle *hp)
{
        BUG_ON(atomic_read(&hp->refcnt) != 0);
        BUG_ON(!list_empty(&hp->list));

        kfree(hp->self_base);
}

static struct mdesc_mem_ops kmalloc_mdesc_memops = {
        .alloc = mdesc_kmalloc,
        .free  = mdesc_kfree,
};

static struct mdesc_handle *mdesc_alloc(unsigned int mdesc_size,
                                        struct mdesc_mem_ops *mops)
{
        struct mdesc_handle *hp = mops->alloc(mdesc_size);

        if (hp)
                hp->mops = mops;

        return hp;
}

static void mdesc_free(struct mdesc_handle *hp)
{
        hp->mops->free(hp);
}

static struct mdesc_handle *cur_mdesc;
static LIST_HEAD(mdesc_zombie_list);
static DEFINE_SPINLOCK(mdesc_lock);

struct mdesc_handle *mdesc_grab(void)
{
        struct mdesc_handle *hp;
        unsigned long flags;

        spin_lock_irqsave(&mdesc_lock, flags);
        hp = cur_mdesc;
        if (hp)
                atomic_inc(&hp->refcnt);
        spin_unlock_irqrestore(&mdesc_lock, flags);

        return hp;
}
EXPORT_SYMBOL(mdesc_grab);

void mdesc_release(struct mdesc_handle *hp)
{
        unsigned long flags;

        spin_lock_irqsave(&mdesc_lock, flags);
        if (atomic_dec_and_test(&hp->refcnt)) {
                list_del_init(&hp->list);
                hp->mops->free(hp);
        }
        spin_unlock_irqrestore(&mdesc_lock, flags);
}
EXPORT_SYMBOL(mdesc_release);

static DEFINE_MUTEX(mdesc_mutex);
static struct mdesc_notifier_client *client_list;

void mdesc_register_notifier(struct mdesc_notifier_client *client)
{
        u64 node;

        mutex_lock(&mdesc_mutex);
        client->next = client_list;
        client_list = client;

        mdesc_for_each_node_by_name(cur_mdesc, node, client->node_name)
                client->add(cur_mdesc, node);

        mutex_unlock(&mdesc_mutex);
}

static const u64 *parent_cfg_handle(struct mdesc_handle *hp, u64 node)
{
        const u64 *id;
        u64 a;

        id = NULL;
        mdesc_for_each_arc(a, hp, node, MDESC_ARC_TYPE_BACK) {
                u64 target;

                target = mdesc_arc_target(hp, a);
                id = mdesc_get_property(hp, target,
                                        "cfg-handle", NULL);
                if (id)
                        break;
        }

        return id;
}

/* Run 'func' on nodes which are in A but not in B.  */
static void invoke_on_missing(const char *name,
                              struct mdesc_handle *a,
                              struct mdesc_handle *b,
                              void (*func)(struct mdesc_handle *, u64))
{
        u64 node;

        mdesc_for_each_node_by_name(a, node, name) {
                int found = 0, is_vdc_port = 0;
                const char *name_prop;
                const u64 *id;
                u64 fnode;

                name_prop = mdesc_get_property(a, node, "name", NULL);
                if (name_prop && !strcmp(name_prop, "vdc-port")) {
                        is_vdc_port = 1;
                        id = parent_cfg_handle(a, node);
                } else
                        id = mdesc_get_property(a, node, "id", NULL);

                if (!id) {
                        printk(KERN_ERR "MD: Cannot find ID for %s node.\n",
                               (name_prop ? name_prop : name));
                        continue;
                }

                mdesc_for_each_node_by_name(b, fnode, name) {
                        const u64 *fid;

                        if (is_vdc_port) {
                                name_prop = mdesc_get_property(b, fnode,
                                                               "name", NULL);
                                if (!name_prop ||
                                    strcmp(name_prop, "vdc-port"))
                                        continue;
                                fid = parent_cfg_handle(b, fnode);
                                if (!fid) {
                                        printk(KERN_ERR "MD: Cannot find ID "
                                               "for vdc-port node.\n");
                                        continue;
                                }
                        } else
                                fid = mdesc_get_property(b, fnode,
                                                         "id", NULL);

                        if (*id == *fid) {
                                found = 1;
                                break;
                        }
                }
                if (!found)
                        func(a, node);
        }
}

static void notify_one(struct mdesc_notifier_client *p,
                       struct mdesc_handle *old_hp,
                       struct mdesc_handle *new_hp)
{
        invoke_on_missing(p->node_name, old_hp, new_hp, p->remove);
        invoke_on_missing(p->node_name, new_hp, old_hp, p->add);
}

static void mdesc_notify_clients(struct mdesc_handle *old_hp,
                                 struct mdesc_handle *new_hp)
{
        struct mdesc_notifier_client *p = client_list;

        while (p) {
                notify_one(p, old_hp, new_hp);
                p = p->next;
        }
}

void mdesc_update(void)
{
        unsigned long len, real_len, status;
        struct mdesc_handle *hp, *orig_hp;
        unsigned long flags;

        mutex_lock(&mdesc_mutex);

        (void) sun4v_mach_desc(0UL, 0UL, &len);

        hp = mdesc_alloc(len, &kmalloc_mdesc_memops);
        if (!hp) {
                printk(KERN_ERR "MD: mdesc alloc fails\n");
                goto out;
        }

        status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
        if (status != HV_EOK || real_len > len) {
                printk(KERN_ERR "MD: mdesc reread fails with %lu\n",
                       status);
                atomic_dec(&hp->refcnt);
                mdesc_free(hp);
                goto out;
        }

        spin_lock_irqsave(&mdesc_lock, flags);
        orig_hp = cur_mdesc;
        cur_mdesc = hp;
        spin_unlock_irqrestore(&mdesc_lock, flags);

        mdesc_notify_clients(orig_hp, hp);

        spin_lock_irqsave(&mdesc_lock, flags);
        if (atomic_dec_and_test(&orig_hp->refcnt))
                mdesc_free(orig_hp);
        else
                list_add(&orig_hp->list, &mdesc_zombie_list);
        spin_unlock_irqrestore(&mdesc_lock, flags);

out:
        mutex_unlock(&mdesc_mutex);
}

static struct mdesc_elem *node_block(struct mdesc_hdr *mdesc)
{
        return (struct mdesc_elem *) (mdesc + 1);
}

static void *name_block(struct mdesc_hdr *mdesc)
{
        return ((void *) node_block(mdesc)) + mdesc->node_sz;
}

static void *data_block(struct mdesc_hdr *mdesc)
{
        return ((void *) name_block(mdesc)) + mdesc->name_sz;
}

u64 mdesc_node_by_name(struct mdesc_handle *hp,
                       u64 from_node, const char *name)
{
        struct mdesc_elem *ep = node_block(&hp->mdesc);
        const char *names = name_block(&hp->mdesc);
        u64 last_node = hp->mdesc.node_sz / 16;
        u64 ret;

        if (from_node == MDESC_NODE_NULL) {
                ret = from_node = 0;
        } else if (from_node >= last_node) {
                return MDESC_NODE_NULL;
        } else {
                ret = ep[from_node].d.val;
        }

        while (ret < last_node) {
                if (ep[ret].tag != MD_NODE)
                        return MDESC_NODE_NULL;
                if (!strcmp(names + ep[ret].name_offset, name))
                        break;
                ret = ep[ret].d.val;
        }
        if (ret >= last_node)
                ret = MDESC_NODE_NULL;
        return ret;
}
EXPORT_SYMBOL(mdesc_node_by_name);

const void *mdesc_get_property(struct mdesc_handle *hp, u64 node,
                               const char *name, int *lenp)
{
        const char *names = name_block(&hp->mdesc);
        u64 last_node = hp->mdesc.node_sz / 16;
        void *data = data_block(&hp->mdesc);
        struct mdesc_elem *ep;

        if (node == MDESC_NODE_NULL || node >= last_node)
                return NULL;

        ep = node_block(&hp->mdesc) + node;
        ep++;
        for (; ep->tag != MD_NODE_END; ep++) {
                void *val = NULL;
                int len = 0;

                switch (ep->tag) {
                case MD_PROP_VAL:
                        val = &ep->d.val;
                        len = 8;
                        break;

                case MD_PROP_STR:
                case MD_PROP_DATA:
                        val = data + ep->d.data.data_offset;
                        len = ep->d.data.data_len;
                        break;

                default:
                        break;
                }
                if (!val)
                        continue;

                if (!strcmp(names + ep->name_offset, name)) {
                        if (lenp)
                                *lenp = len;
                        return val;
                }
        }

        return NULL;
}
EXPORT_SYMBOL(mdesc_get_property);

u64 mdesc_next_arc(struct mdesc_handle *hp, u64 from, const char *arc_type)
{
        struct mdesc_elem *ep, *base = node_block(&hp->mdesc);
        const char *names = name_block(&hp->mdesc);
        u64 last_node = hp->mdesc.node_sz / 16;

        if (from == MDESC_NODE_NULL || from >= last_node)
                return MDESC_NODE_NULL;

        ep = base + from;

        ep++;
        for (; ep->tag != MD_NODE_END; ep++) {
                if (ep->tag != MD_PROP_ARC)
                        continue;

                if (strcmp(names + ep->name_offset, arc_type))
                        continue;

                return ep - base;
        }

        return MDESC_NODE_NULL;
}
EXPORT_SYMBOL(mdesc_next_arc);

u64 mdesc_arc_target(struct mdesc_handle *hp, u64 arc)
{
        struct mdesc_elem *ep, *base = node_block(&hp->mdesc);

        ep = base + arc;

        return ep->d.val;
}
EXPORT_SYMBOL(mdesc_arc_target);

const char *mdesc_node_name(struct mdesc_handle *hp, u64 node)
{
        struct mdesc_elem *ep, *base = node_block(&hp->mdesc);
        const char *names = name_block(&hp->mdesc);
        u64 last_node = hp->mdesc.node_sz / 16;

        if (node == MDESC_NODE_NULL || node >= last_node)
                return NULL;

        ep = base + node;
        if (ep->tag != MD_NODE)
                return NULL;

        return names + ep->name_offset;
}
EXPORT_SYMBOL(mdesc_node_name);

static u64 max_cpus = 64;

static void __init report_platform_properties(void)
{
        struct mdesc_handle *hp = mdesc_grab();
        u64 pn = mdesc_node_by_name(hp, MDESC_NODE_NULL, "platform");
        const char *s;
        const u64 *v;

        if (pn == MDESC_NODE_NULL) {
                prom_printf("No platform node in machine-description.\n");
                prom_halt();
        }

        s = mdesc_get_property(hp, pn, "banner-name", NULL);
        printk("PLATFORM: banner-name [%s]\n", s);
        s = mdesc_get_property(hp, pn, "name", NULL);
        printk("PLATFORM: name [%s]\n", s);

        v = mdesc_get_property(hp, pn, "hostid", NULL);
        if (v)
                printk("PLATFORM: hostid [%08llx]\n", *v);
        v = mdesc_get_property(hp, pn, "serial#", NULL);
        if (v)
                printk("PLATFORM: serial# [%08llx]\n", *v);
        v = mdesc_get_property(hp, pn, "stick-frequency", NULL);
        printk("PLATFORM: stick-frequency [%08llx]\n", *v);
        v = mdesc_get_property(hp, pn, "mac-address", NULL);
        if (v)
                printk("PLATFORM: mac-address [%llx]\n", *v);
        v = mdesc_get_property(hp, pn, "watchdog-resolution", NULL);
        if (v)
                printk("PLATFORM: watchdog-resolution [%llu ms]\n", *v);
        v = mdesc_get_property(hp, pn, "watchdog-max-timeout", NULL);
        if (v)
                printk("PLATFORM: watchdog-max-timeout [%llu ms]\n", *v);
        v = mdesc_get_property(hp, pn, "max-cpus", NULL);
        if (v) {
                max_cpus = *v;
                printk("PLATFORM: max-cpus [%llu]\n", max_cpus);
        }

#ifdef CONFIG_SMP
        {
                int max_cpu, i;

                if (v) {
                        max_cpu = *v;
                        if (max_cpu > NR_CPUS)
                                max_cpu = NR_CPUS;
                } else {
                        max_cpu = NR_CPUS;
                }
                for (i = 0; i < max_cpu; i++)
                        set_cpu_possible(i, true);
        }
#endif

        mdesc_release(hp);
}

static void fill_in_one_cache(cpuinfo_sparc *c, struct mdesc_handle *hp, u64 mp)
{
        const u64 *level = mdesc_get_property(hp, mp, "level", NULL);
        const u64 *size = mdesc_get_property(hp, mp, "size", NULL);
        const u64 *line_size = mdesc_get_property(hp, mp, "line-size", NULL);
        const char *type;
        int type_len;

        type = mdesc_get_property(hp, mp, "type", &type_len);

        switch (*level) {
        case 1:
                if (of_find_in_proplist(type, "instn", type_len)) {
                        c->icache_size = *size;
                        c->icache_line_size = *line_size;
                } else if (of_find_in_proplist(type, "data", type_len)) {
                        c->dcache_size = *size;
                        c->dcache_line_size = *line_size;
                }
                break;

        case 2:
                c->ecache_size = *size;
                c->ecache_line_size = *line_size;
                break;

        default:
                break;
        }

        if (*level == 1) {
                u64 a;

                mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
                        u64 target = mdesc_arc_target(hp, a);
                        const char *name = mdesc_node_name(hp, target);

                        if (!strcmp(name, "cache"))
                                fill_in_one_cache(c, hp, target);
                }
        }
}

static void find_back_node_value(struct mdesc_handle *hp, u64 node,
                                 char *srch_val,
                                 void (*func)(struct mdesc_handle *, u64, int),
                                 u64 val, int depth)
{
        u64 arc;

        /* Since we have an estimate of recursion depth, do a sanity check. */
        if (depth == 0)
                return;

        mdesc_for_each_arc(arc, hp, node, MDESC_ARC_TYPE_BACK) {
                u64 n = mdesc_arc_target(hp, arc);
                const char *name = mdesc_node_name(hp, n);

                if (!strcmp(srch_val, name))
                        (*func)(hp, n, val);

                find_back_node_value(hp, n, srch_val, func, val, depth-1);
        }
}

static void __mark_core_id(struct mdesc_handle *hp, u64 node,
                           int core_id)
{
        const u64 *id = mdesc_get_property(hp, node, "id", NULL);

        if (*id < num_possible_cpus())
                cpu_data(*id).core_id = core_id;
}

static void __mark_sock_id(struct mdesc_handle *hp, u64 node,
                           int sock_id)
{
        const u64 *id = mdesc_get_property(hp, node, "id", NULL);

        if (*id < num_possible_cpus())
                cpu_data(*id).sock_id = sock_id;
}

static void mark_core_ids(struct mdesc_handle *hp, u64 mp,
                          int core_id)
{
        find_back_node_value(hp, mp, "cpu", __mark_core_id, core_id, 10);
}

static void mark_sock_ids(struct mdesc_handle *hp, u64 mp,
                          int sock_id)
{
        find_back_node_value(hp, mp, "cpu", __mark_sock_id, sock_id, 10);
}

static void set_core_ids(struct mdesc_handle *hp)
{
        int idx;
        u64 mp;

        idx = 1;

        /* Identify unique cores by looking for cpus backpointed to by
         * level 1 instruction caches.
         */
        mdesc_for_each_node_by_name(hp, mp, "cache") {
                const u64 *level;
                const char *type;
                int len;

                level = mdesc_get_property(hp, mp, "level", NULL);
                if (*level != 1)
                        continue;

                type = mdesc_get_property(hp, mp, "type", &len);
                if (!of_find_in_proplist(type, "instn", len))
                        continue;

                mark_core_ids(hp, mp, idx);
                idx++;
        }
}

static int set_sock_ids_by_cache(struct mdesc_handle *hp, int level)
{
        u64 mp;
        int idx = 1;
        int fnd = 0;

        /* Identify unique sockets by looking for cpus backpointed to by
         * shared level n caches.
         */
        mdesc_for_each_node_by_name(hp, mp, "cache") {
                const u64 *cur_lvl;

                cur_lvl = mdesc_get_property(hp, mp, "level", NULL);
                if (*cur_lvl != level)
                        continue;

                mark_sock_ids(hp, mp, idx);
                idx++;
                fnd = 1;
        }
        return fnd;
}

static void set_sock_ids_by_socket(struct mdesc_handle *hp, u64 mp)
{
        int idx = 1;

        mdesc_for_each_node_by_name(hp, mp, "socket") {
                u64 a;

                mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
                        u64 t = mdesc_arc_target(hp, a);
                        const char *name;
                        const u64 *id;

                        name = mdesc_node_name(hp, t);
                        if (strcmp(name, "cpu"))
                                continue;

                        id = mdesc_get_property(hp, t, "id", NULL);
                        if (*id < num_possible_cpus())
                                cpu_data(*id).sock_id = idx;
                }
                idx++;
        }
}

static void set_sock_ids(struct mdesc_handle *hp)
{
        u64 mp;

        /* If machine description exposes sockets data use it.
         * Otherwise fallback to use shared L3 or L2 caches.
         */
        mp = mdesc_node_by_name(hp, MDESC_NODE_NULL, "sockets");
        if (mp != MDESC_NODE_NULL)
                return set_sock_ids_by_socket(hp, mp);

        if (!set_sock_ids_by_cache(hp, 3))
                set_sock_ids_by_cache(hp, 2);
}

static void mark_proc_ids(struct mdesc_handle *hp, u64 mp, int proc_id)
{
        u64 a;

        mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_BACK) {
                u64 t = mdesc_arc_target(hp, a);
                const char *name;
                const u64 *id;

                name = mdesc_node_name(hp, t);
                if (strcmp(name, "cpu"))
                        continue;

                id = mdesc_get_property(hp, t, "id", NULL);
                if (*id < NR_CPUS)
                        cpu_data(*id).proc_id = proc_id;
        }
}

static void __set_proc_ids(struct mdesc_handle *hp, const char *exec_unit_name)
{
        int idx;
        u64 mp;

        idx = 0;
        mdesc_for_each_node_by_name(hp, mp, exec_unit_name) {
                const char *type;
                int len;

                type = mdesc_get_property(hp, mp, "type", &len);
                if (!of_find_in_proplist(type, "int", len) &&
                    !of_find_in_proplist(type, "integer", len))
                        continue;

                mark_proc_ids(hp, mp, idx);
                idx++;
        }
}

static void set_proc_ids(struct mdesc_handle *hp)
{
        __set_proc_ids(hp, "exec_unit");
        __set_proc_ids(hp, "exec-unit");
}

static void get_one_mondo_bits(const u64 *p, unsigned int *mask,
                               unsigned long def, unsigned long max)
{
        u64 val;

        if (!p)
                goto use_default;
        val = *p;

        if (!val || val >= 64)
                goto use_default;

        if (val > max)
                val = max;

        *mask = ((1U << val) * 64U) - 1U;
        return;

use_default:
        *mask = ((1U << def) * 64U) - 1U;
}

static void get_mondo_data(struct mdesc_handle *hp, u64 mp,
                           struct trap_per_cpu *tb)
{
        static int printed;
        const u64 *val;

        val = mdesc_get_property(hp, mp, "q-cpu-mondo-#bits", NULL);
        get_one_mondo_bits(val, &tb->cpu_mondo_qmask, 7, ilog2(max_cpus * 2));

        val = mdesc_get_property(hp, mp, "q-dev-mondo-#bits", NULL);
        get_one_mondo_bits(val, &tb->dev_mondo_qmask, 7, 8);

        val = mdesc_get_property(hp, mp, "q-resumable-#bits", NULL);
        get_one_mondo_bits(val, &tb->resum_qmask, 6, 7);

        val = mdesc_get_property(hp, mp, "q-nonresumable-#bits", NULL);
        get_one_mondo_bits(val, &tb->nonresum_qmask, 2, 2);
        if (!printed++) {
                pr_info("SUN4V: Mondo queue sizes "
                        "[cpu(%u) dev(%u) r(%u) nr(%u)]\n",
                        tb->cpu_mondo_qmask + 1,
                        tb->dev_mondo_qmask + 1,
                        tb->resum_qmask + 1,
                        tb->nonresum_qmask + 1);
        }
}

static void *mdesc_iterate_over_cpus(void *(*func)(struct mdesc_handle *, u64, int, void *), void *arg, cpumask_t *mask)
{
        struct mdesc_handle *hp = mdesc_grab();
        void *ret = NULL;
        u64 mp;

        mdesc_for_each_node_by_name(hp, mp, "cpu") {
                const u64 *id = mdesc_get_property(hp, mp, "id", NULL);
                int cpuid = *id;

#ifdef CONFIG_SMP
                if (cpuid >= NR_CPUS) {
                        printk(KERN_WARNING "Ignoring CPU %d which is "
                               ">= NR_CPUS (%d)\n",
                               cpuid, NR_CPUS);
                        continue;
                }
                if (!cpumask_test_cpu(cpuid, mask))
                        continue;
#endif

                ret = func(hp, mp, cpuid, arg);
                if (ret)
                        goto out;
        }
out:
        mdesc_release(hp);
        return ret;
}

static void *record_one_cpu(struct mdesc_handle *hp, u64 mp, int cpuid,
                            void *arg)
{
        ncpus_probed++;
#ifdef CONFIG_SMP
        set_cpu_present(cpuid, true);
#endif
        return NULL;
}

void mdesc_populate_present_mask(cpumask_t *mask)
{
        if (tlb_type != hypervisor)
                return;

        ncpus_probed = 0;
        mdesc_iterate_over_cpus(record_one_cpu, NULL, mask);
}

static void * __init check_one_pgsz(struct mdesc_handle *hp, u64 mp, int cpuid, void *arg)
{
        const u64 *pgsz_prop = mdesc_get_property(hp, mp, "mmu-page-size-list", NULL);
        unsigned long *pgsz_mask = arg;
        u64 val;

        val = (HV_PGSZ_MASK_8K | HV_PGSZ_MASK_64K |
               HV_PGSZ_MASK_512K | HV_PGSZ_MASK_4MB);
        if (pgsz_prop)
                val = *pgsz_prop;

        if (!*pgsz_mask)
                *pgsz_mask = val;
        else
                *pgsz_mask &= val;
        return NULL;
}

void __init mdesc_get_page_sizes(cpumask_t *mask, unsigned long *pgsz_mask)
{
        *pgsz_mask = 0;
        mdesc_iterate_over_cpus(check_one_pgsz, pgsz_mask, mask);
}

static void *fill_in_one_cpu(struct mdesc_handle *hp, u64 mp, int cpuid,
                             void *arg)
{
        const u64 *cfreq = mdesc_get_property(hp, mp, "clock-frequency", NULL);
        struct trap_per_cpu *tb;
        cpuinfo_sparc *c;
        u64 a;

#ifndef CONFIG_SMP
        /* On uniprocessor we only want the values for the
         * real physical cpu the kernel booted onto, however
         * cpu_data() only has one entry at index 0.
         */
        if (cpuid != real_hard_smp_processor_id())
                return NULL;
        cpuid = 0;
#endif

        c = &cpu_data(cpuid);
        c->clock_tick = *cfreq;

        tb = &trap_block[cpuid];
        get_mondo_data(hp, mp, tb);

        mdesc_for_each_arc(a, hp, mp, MDESC_ARC_TYPE_FWD) {
                u64 j, t = mdesc_arc_target(hp, a);
                const char *t_name;

                t_name = mdesc_node_name(hp, t);
                if (!strcmp(t_name, "cache")) {
                        fill_in_one_cache(c, hp, t);
                        continue;
                }

                mdesc_for_each_arc(j, hp, t, MDESC_ARC_TYPE_FWD) {
                        u64 n = mdesc_arc_target(hp, j);
                        const char *n_name;

                        n_name = mdesc_node_name(hp, n);
                        if (!strcmp(n_name, "cache"))
                                fill_in_one_cache(c, hp, n);
                }
        }

        c->core_id = 0;
        c->proc_id = -1;

        return NULL;
}

void mdesc_fill_in_cpu_data(cpumask_t *mask)
{
        struct mdesc_handle *hp;

        mdesc_iterate_over_cpus(fill_in_one_cpu, NULL, mask);

        hp = mdesc_grab();

        set_core_ids(hp);
        set_proc_ids(hp);
        set_sock_ids(hp);

        mdesc_release(hp);

        smp_fill_in_sib_core_maps();
}

/* mdesc_open() - Grab a reference to mdesc_handle when /dev/mdesc is
 * opened. Hold this reference until /dev/mdesc is closed to ensure
 * mdesc data structure is not released underneath us. Store the
 * pointer to mdesc structure in private_data for read and seek to use
 */
static int mdesc_open(struct inode *inode, struct file *file)
{
        struct mdesc_handle *hp = mdesc_grab();

        if (!hp)
                return -ENODEV;

        file->private_data = hp;

        return 0;
}

static ssize_t mdesc_read(struct file *file, char __user *buf,
                          size_t len, loff_t *offp)
{
        struct mdesc_handle *hp = file->private_data;
        unsigned char *mdesc;
        int bytes_left, count = len;

        if (*offp >= hp->handle_size)
                return 0;

        bytes_left = hp->handle_size - *offp;
        if (count > bytes_left)
                count = bytes_left;

        mdesc = (unsigned char *)&hp->mdesc;
        mdesc += *offp;
        if (!copy_to_user(buf, mdesc, count)) {
                *offp += count;
                return count;
        } else {
                return -EFAULT;
        }
}

static loff_t mdesc_llseek(struct file *file, loff_t offset, int whence)
{
        struct mdesc_handle *hp = file->private_data;

        return no_seek_end_llseek_size(file, offset, whence, hp->handle_size);
}

/* mdesc_close() - /dev/mdesc is being closed, release the reference to
 * mdesc structure.
 */
static int mdesc_close(struct inode *inode, struct file *file)
{
        mdesc_release(file->private_data);
        return 0;
}

static const struct file_operations mdesc_fops = {
        .open    = mdesc_open,
        .read    = mdesc_read,
        .llseek  = mdesc_llseek,
        .release = mdesc_close,
        .owner   = THIS_MODULE,
};

static struct miscdevice mdesc_misc = {
        .minor  = MISC_DYNAMIC_MINOR,
        .name   = "mdesc",
        .fops   = &mdesc_fops,
};

static int __init mdesc_misc_init(void)
{
        return misc_register(&mdesc_misc);
}

__initcall(mdesc_misc_init);

void __init sun4v_mdesc_init(void)
{
        struct mdesc_handle *hp;
        unsigned long len, real_len, status;

        (void) sun4v_mach_desc(0UL, 0UL, &len);

        printk("MDESC: Size is %lu bytes.\n", len);

        hp = mdesc_alloc(len, &memblock_mdesc_ops);
        if (hp == NULL) {
                prom_printf("MDESC: alloc of %lu bytes failed.\n", len);
                prom_halt();
        }

        status = sun4v_mach_desc(__pa(&hp->mdesc), len, &real_len);
        if (status != HV_EOK || real_len > len) {
                prom_printf("sun4v_mach_desc fails, err(%lu), "
                            "len(%lu), real_len(%lu)\n",
                            status, len, real_len);
                mdesc_free(hp);
                prom_halt();
        }

        cur_mdesc = hp;

        report_platform_properties();
}