/*
 *  (c) 2005, 2006 Advanced Micro Devices, Inc.
 *  Your use of this code is subject to the terms and conditions of the
 *  GNU general public license version 2. See "COPYING" or
 *  http://www.gnu.org/licenses/gpl.html
 *
 *  Written by Jacob Shin - AMD, Inc.
 *
 *  Support : jacob.shin@amd.com
 *
 *  April 2006
 *     - added support for AMD Family 0x10 processors
 *
 *  All MC4_MISCi registers are shared between multi-cores
 */
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/kobject.h>
#include <linux/percpu.h>
#include <linux/sysdev.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/sysfs.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/smp.h>

#include <asm/apic.h>
#include <asm/idle.h>
#include <asm/mce.h>
#include <asm/msr.h>

#define NR_BANKS          6
#define NR_BLOCKS         9
#define THRESHOLD_MAX     0xFFF
#define INT_TYPE_APIC     0x00020000
#define MASK_VALID_HI     0x80000000
#define MASK_CNTP_HI      0x40000000
#define MASK_LOCKED_HI    0x20000000
#define MASK_LVTOFF_HI    0x00F00000
#define MASK_COUNT_EN_HI  0x00080000
#define MASK_INT_TYPE_HI  0x00060000
#define MASK_OVERFLOW_HI  0x00010000
#define MASK_ERR_COUNT_HI 0x00000FFF
#define MASK_BLKPTR_LO    0xFF000000
#define MCG_XBLK_ADDR     0xC0000400

struct threshold_block {
        unsigned int            block;
        unsigned int            bank;
        unsigned int            cpu;
        u32                     address;
        u16                     interrupt_enable;
        u16                     threshold_limit;
        struct kobject          kobj;
        struct list_head        miscj;
};

struct threshold_bank {
        struct kobject          *kobj;
        struct threshold_block  *blocks;
        cpumask_var_t           cpus;
};
static DEFINE_PER_CPU(struct threshold_bank * [NR_BANKS], threshold_banks);

#ifdef CONFIG_SMP
static unsigned char shared_bank[NR_BANKS] = {
        0, 0, 0, 0, 1
};
#endif

static DEFINE_PER_CPU(unsigned char, bank_map); /* see which banks are on */

static void amd_threshold_interrupt(void);

/*
 * CPU Initialization
 */

struct thresh_restart {
        struct threshold_block  *b;
        int                     reset;
        int                     set_lvt_off;
        int                     lvt_off;
        u16                     old_limit;
};

static int lvt_off_valid(struct threshold_block *b, int apic, u32 lo, u32 hi)
{
        int msr = (hi & MASK_LVTOFF_HI) >> 20;

        if (apic < 0) {
                pr_err(FW_BUG "cpu %d, failed to setup threshold interrupt "
                       "for bank %d, block %d (MSR%08X=0x%x%08x)\n", b->cpu,
                       b->bank, b->block, b->address, hi, lo);
                return 0;
        }

        if (apic != msr) {
                pr_err(FW_BUG "cpu %d, invalid threshold interrupt offset %d "
                       "for bank %d, block %d (MSR%08X=0x%x%08x)\n",
                       b->cpu, apic, b->bank, b->block, b->address, hi, lo);
                return 0;
        }

        return 1;
};

/* must be called with correct cpu affinity */
/* Called via smp_call_function_single() */
static void threshold_restart_bank(void *_tr)
{
        struct thresh_restart *tr = _tr;
        u32 hi, lo;

        rdmsr(tr->b->address, lo, hi);

        if (tr->b->threshold_limit < (hi & THRESHOLD_MAX))
                tr->reset = 1;  /* limit cannot be lower than err count */

        if (tr->reset) {                /* reset err count and overflow bit */
                hi =
                    (hi & ~(MASK_ERR_COUNT_HI | MASK_OVERFLOW_HI)) |
                    (THRESHOLD_MAX - tr->b->threshold_limit);
        } else if (tr->old_limit) {     /* change limit w/o reset */
                int new_count = (hi & THRESHOLD_MAX) +
                    (tr->old_limit - tr->b->threshold_limit);

                hi = (hi & ~MASK_ERR_COUNT_HI) |
                    (new_count & THRESHOLD_MAX);
        }

        if (tr->set_lvt_off) {
                if (lvt_off_valid(tr->b, tr->lvt_off, lo, hi)) {
                        /* set new lvt offset */
                        hi &= ~MASK_LVTOFF_HI;
                        hi |= tr->lvt_off << 20;
                }
        }

        tr->b->interrupt_enable ?
            (hi = (hi & ~MASK_INT_TYPE_HI) | INT_TYPE_APIC) :
            (hi &= ~MASK_INT_TYPE_HI);

        hi |= MASK_COUNT_EN_HI;
        wrmsr(tr->b->address, lo, hi);
}

static void mce_threshold_block_init(struct threshold_block *b, int offset)
{
        struct thresh_restart tr = {
                .b                      = b,
                .set_lvt_off            = 1,
                .lvt_off                = offset,
        };

        b->threshold_limit              = THRESHOLD_MAX;
        threshold_restart_bank(&tr);
};

static int setup_APIC_mce(int reserved, int new)
{
        if (reserved < 0 && !setup_APIC_eilvt(new, THRESHOLD_APIC_VECTOR,
                                              APIC_EILVT_MSG_FIX, 0))
                return new;

        return reserved;
}

/* cpu init entry point, called from mce.c with preempt off */
void mce_amd_feature_init(struct cpuinfo_x86 *c)
{
        struct threshold_block b;
        unsigned int cpu = smp_processor_id();
        u32 low = 0, high = 0, address = 0;
        unsigned int bank, block;
        int offset = -1;

        for (bank = 0; bank < NR_BANKS; ++bank) {
                for (block = 0; block < NR_BLOCKS; ++block) {
                        if (block == 0)
                                address = MSR_IA32_MC0_MISC + bank * 4;
                        else if (block == 1) {
                                address = (low & MASK_BLKPTR_LO) >> 21;
                                if (!address)
                                        break;

                                address += MCG_XBLK_ADDR;
                        } else
                                ++address;

                        if (rdmsr_safe(address, &low, &high))
                                break;

                        if (!(high & MASK_VALID_HI))
                                continue;

                        if (!(high & MASK_CNTP_HI)  ||
                             (high & MASK_LOCKED_HI))
                                continue;

                        if (!block)
                                per_cpu(bank_map, cpu) |= (1 << bank);
#ifdef CONFIG_SMP
                        if (shared_bank[bank] && c->cpu_core_id)
                                break;
#endif
                        offset = setup_APIC_mce(offset,
                                                (high & MASK_LVTOFF_HI) >> 20);

                        memset(&b, 0, sizeof(b));
                        b.cpu           = cpu;
                        b.bank          = bank;
                        b.block         = block;
                        b.address       = address;

                        mce_threshold_block_init(&b, offset);
                        mce_threshold_vector = amd_threshold_interrupt;
                }
        }
}

/*
 * APIC Interrupt Handler
 */

/*
 * threshold interrupt handler will service THRESHOLD_APIC_VECTOR.
 * the interrupt goes off when error_count reaches threshold_limit.
 * the handler will simply log mcelog w/ software defined bank number.
 */
static void amd_threshold_interrupt(void)
{
        u32 low = 0, high = 0, address = 0;
        unsigned int bank, block;
        struct mce m;

        mce_setup(&m);

        /* assume first bank caused it */
        for (bank = 0; bank < NR_BANKS; ++bank) {
                if (!(per_cpu(bank_map, m.cpu) & (1 << bank)))
                        continue;
                for (block = 0; block < NR_BLOCKS; ++block) {
                        if (block == 0) {
                                address = MSR_IA32_MC0_MISC + bank * 4;
                        } else if (block == 1) {
                                address = (low & MASK_BLKPTR_LO) >> 21;
                                if (!address)
                                        break;
                                address += MCG_XBLK_ADDR;
                        } else {
                                ++address;
                        }

                        if (rdmsr_safe(address, &low, &high))
                                break;

                        if (!(high & MASK_VALID_HI)) {
                                if (block)
                                        continue;
                                else
                                        break;
                        }

                        if (!(high & MASK_CNTP_HI)  ||
                             (high & MASK_LOCKED_HI))
                                continue;

                        /*
                         * Log the machine check that caused the threshold
                         * event.
                         */
                        machine_check_poll(MCP_TIMESTAMP,
                                        &__get_cpu_var(mce_poll_banks));

                        if (high & MASK_OVERFLOW_HI) {
                                rdmsrl(address, m.misc);
                                rdmsrl(MSR_IA32_MC0_STATUS + bank * 4,
                                       m.status);
                                m.bank = K8_MCE_THRESHOLD_BASE
                                       + bank * NR_BLOCKS
                                       + block;
                                mce_log(&m);
                                return;
                        }
                }
        }
}

/*
 * Sysfs Interface
 */

struct threshold_attr {
        struct attribute attr;
        ssize_t (*show) (struct threshold_block *, char *);
        ssize_t (*store) (struct threshold_block *, const char *, size_t count);
};

#define SHOW_FIELDS(name)                                               \
static ssize_t show_ ## name(struct threshold_block *b, char *buf)      \
{                                                                       \
        return sprintf(buf, "%lx\n", (unsigned long) b->name);          \
}
SHOW_FIELDS(interrupt_enable)
SHOW_FIELDS(threshold_limit)

static ssize_t
store_interrupt_enable(struct threshold_block *b, const char *buf, size_t size)
{
        struct thresh_restart tr;
        unsigned long new;

        if (strict_strtoul(buf, 0, &new) < 0)
                return -EINVAL;

        b->interrupt_enable = !!new;

        memset(&tr, 0, sizeof(tr));
        tr.b            = b;

        smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);

        return size;
}

static ssize_t
store_threshold_limit(struct threshold_block *b, const char *buf, size_t size)
{
        struct thresh_restart tr;
        unsigned long new;

        if (strict_strtoul(buf, 0, &new) < 0)
                return -EINVAL;

        if (new > THRESHOLD_MAX)
                new = THRESHOLD_MAX;
        if (new < 1)
                new = 1;

        memset(&tr, 0, sizeof(tr));
        tr.old_limit = b->threshold_limit;
        b->threshold_limit = new;
        tr.b = b;

        smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);

        return size;
}

struct threshold_block_cross_cpu {
        struct threshold_block  *tb;
        long                    retval;
};

static void local_error_count_handler(void *_tbcc)
{
        struct threshold_block_cross_cpu *tbcc = _tbcc;
        struct threshold_block *b = tbcc->tb;
        u32 low, high;

        rdmsr(b->address, low, high);
        tbcc->retval = (high & 0xFFF) - (THRESHOLD_MAX - b->threshold_limit);
}

static ssize_t show_error_count(struct threshold_block *b, char *buf)
{
        struct threshold_block_cross_cpu tbcc = { .tb = b, };

        smp_call_function_single(b->cpu, local_error_count_handler, &tbcc, 1);
        return sprintf(buf, "%lx\n", tbcc.retval);
}

static ssize_t store_error_count(struct threshold_block *b,
                                 const char *buf, size_t count)
{
        struct thresh_restart tr = { .b = b, .reset = 1, .old_limit = 0 };

        smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1);
        return 1;
}

#define RW_ATTR(val)                                                    \
static struct threshold_attr val = {                                    \
        .attr   = {.name = __stringify(val), .mode = 0644 },            \
        .show   = show_## val,                                          \
        .store  = store_## val,                                         \
};

RW_ATTR(interrupt_enable);
RW_ATTR(threshold_limit);
RW_ATTR(error_count);

static struct attribute *default_attrs[] = {
        &interrupt_enable.attr,
        &threshold_limit.attr,
        &error_count.attr,
        NULL
};

#define to_block(k)     container_of(k, struct threshold_block, kobj)
#define to_attr(a)      container_of(a, struct threshold_attr, attr)

static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
{
        struct threshold_block *b = to_block(kobj);
        struct threshold_attr *a = to_attr(attr);
        ssize_t ret;

        ret = a->show ? a->show(b, buf) : -EIO;

        return ret;
}

static ssize_t store(struct kobject *kobj, struct attribute *attr,
                     const char *buf, size_t count)
{
        struct threshold_block *b = to_block(kobj);
        struct threshold_attr *a = to_attr(attr);
        ssize_t ret;

        ret = a->store ? a->store(b, buf, count) : -EIO;

        return ret;
}

static const struct sysfs_ops threshold_ops = {
        .show                   = show,
        .store                  = store,
};

static struct kobj_type threshold_ktype = {
        .sysfs_ops              = &threshold_ops,
        .default_attrs          = default_attrs,
};

static __cpuinit int allocate_threshold_blocks(unsigned int cpu,
                                               unsigned int bank,
                                               unsigned int block,
                                               u32 address)
{
        struct threshold_block *b = NULL;
        u32 low, high;
        int err;

        if ((bank >= NR_BANKS) || (block >= NR_BLOCKS))
                return 0;

        if (rdmsr_safe_on_cpu(cpu, address, &low, &high))
                return 0;

        if (!(high & MASK_VALID_HI)) {
                if (block)
                        goto recurse;
                else
                        return 0;
        }

        if (!(high & MASK_CNTP_HI)  ||
             (high & MASK_LOCKED_HI))
                goto recurse;

        b = kzalloc(sizeof(struct threshold_block), GFP_KERNEL);
        if (!b)
                return -ENOMEM;

        b->block                = block;
        b->bank                 = bank;
        b->cpu                  = cpu;
        b->address              = address;
        b->interrupt_enable     = 0;
        b->threshold_limit      = THRESHOLD_MAX;

        INIT_LIST_HEAD(&b->miscj);

        if (per_cpu(threshold_banks, cpu)[bank]->blocks) {
                list_add(&b->miscj,
                         &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj);
        } else {
                per_cpu(threshold_banks, cpu)[bank]->blocks = b;
        }

        err = kobject_init_and_add(&b->kobj, &threshold_ktype,
                                   per_cpu(threshold_banks, cpu)[bank]->kobj,
                                   "misc%i", block);
        if (err)
                goto out_free;
recurse:
        if (!block) {
                address = (low & MASK_BLKPTR_LO) >> 21;
                if (!address)
                        return 0;
                address += MCG_XBLK_ADDR;
        } else {
                ++address;
        }

        err = allocate_threshold_blocks(cpu, bank, ++block, address);
        if (err)
                goto out_free;

        if (b)
                kobject_uevent(&b->kobj, KOBJ_ADD);

        return err;

out_free:
        if (b) {
                kobject_put(&b->kobj);
                list_del(&b->miscj);
                kfree(b);
        }
        return err;
}

static __cpuinit long
local_allocate_threshold_blocks(int cpu, unsigned int bank)
{
        return allocate_threshold_blocks(cpu, bank, 0,
                                         MSR_IA32_MC0_MISC + bank * 4);
}

/* symlinks sibling shared banks to first core.  first core owns dir/files. */
static __cpuinit int threshold_create_bank(unsigned int cpu, unsigned int bank)
{
        int i, err = 0;
        struct threshold_bank *b = NULL;
        char name[32];

        sprintf(name, "threshold_bank%i", bank);

#ifdef CONFIG_SMP
        if (cpu_data(cpu).cpu_core_id && shared_bank[bank]) {   /* symlink */
                i = cpumask_first(cpu_llc_shared_mask(cpu));

                /* first core not up yet */
                if (cpu_data(i).cpu_core_id)
                        goto out;

                /* already linked */
                if (per_cpu(threshold_banks, cpu)[bank])
                        goto out;

                b = per_cpu(threshold_banks, i)[bank];

                if (!b)
                        goto out;

                err = sysfs_create_link(&per_cpu(mce_sysdev, cpu).kobj,
                                        b->kobj, name);
                if (err)
                        goto out;

                cpumask_copy(b->cpus, cpu_llc_shared_mask(cpu));
                per_cpu(threshold_banks, cpu)[bank] = b;

                goto out;
        }
#endif

        b = kzalloc(sizeof(struct threshold_bank), GFP_KERNEL);
        if (!b) {
                err = -ENOMEM;
                goto out;
        }
        if (!zalloc_cpumask_var(&b->cpus, GFP_KERNEL)) {
                kfree(b);
                err = -ENOMEM;
                goto out;
        }

        b->kobj = kobject_create_and_add(name, &per_cpu(mce_sysdev, cpu).kobj);
        if (!b->kobj)
                goto out_free;

#ifndef CONFIG_SMP
        cpumask_setall(b->cpus);
#else
        cpumask_set_cpu(cpu, b->cpus);
#endif

        per_cpu(threshold_banks, cpu)[bank] = b;

        err = local_allocate_threshold_blocks(cpu, bank);
        if (err)
                goto out_free;

        for_each_cpu(i, b->cpus) {
                if (i == cpu)
                        continue;

                err = sysfs_create_link(&per_cpu(mce_sysdev, i).kobj,
                                        b->kobj, name);
                if (err)
                        goto out;

                per_cpu(threshold_banks, i)[bank] = b;
        }

        goto out;

out_free:
        per_cpu(threshold_banks, cpu)[bank] = NULL;
        free_cpumask_var(b->cpus);
        kfree(b);
out:
        return err;
}

/* create dir/files for all valid threshold banks */
static __cpuinit int threshold_create_device(unsigned int cpu)
{
        unsigned int bank;
        int err = 0;

        for (bank = 0; bank < NR_BANKS; ++bank) {
                if (!(per_cpu(bank_map, cpu) & (1 << bank)))
                        continue;
                err = threshold_create_bank(cpu, bank);
                if (err)
                        return err;
        }

        return err;
}

/*
 * let's be hotplug friendly.
 * in case of multiple core processors, the first core always takes ownership
 *   of shared sysfs dir/files, and rest of the cores will be symlinked to it.
 */

static void deallocate_threshold_block(unsigned int cpu,
                                                 unsigned int bank)
{
        struct threshold_block *pos = NULL;
        struct threshold_block *tmp = NULL;
        struct threshold_bank *head = per_cpu(threshold_banks, cpu)[bank];

        if (!head)
                return;

        list_for_each_entry_safe(pos, tmp, &head->blocks->miscj, miscj) {
                kobject_put(&pos->kobj);
                list_del(&pos->miscj);
                kfree(pos);
        }

        kfree(per_cpu(threshold_banks, cpu)[bank]->blocks);
        per_cpu(threshold_banks, cpu)[bank]->blocks = NULL;
}

static void threshold_remove_bank(unsigned int cpu, int bank)
{
        struct threshold_bank *b;
        char name[32];
        int i = 0;

        b = per_cpu(threshold_banks, cpu)[bank];
        if (!b)
                return;
        if (!b->blocks)
                goto free_out;

        sprintf(name, "threshold_bank%i", bank);

#ifdef CONFIG_SMP
        /* sibling symlink */
        if (shared_bank[bank] && b->blocks->cpu != cpu) {
                sysfs_remove_link(&per_cpu(mce_sysdev, cpu).kobj, name);
                per_cpu(threshold_banks, cpu)[bank] = NULL;

                return;
        }
#endif

        /* remove all sibling symlinks before unregistering */
        for_each_cpu(i, b->cpus) {
                if (i == cpu)
                        continue;

                sysfs_remove_link(&per_cpu(mce_sysdev, i).kobj, name);
                per_cpu(threshold_banks, i)[bank] = NULL;
        }

        deallocate_threshold_block(cpu, bank);

free_out:
        kobject_del(b->kobj);
        kobject_put(b->kobj);
        free_cpumask_var(b->cpus);
        kfree(b);
        per_cpu(threshold_banks, cpu)[bank] = NULL;
}

static void threshold_remove_device(unsigned int cpu)
{
        unsigned int bank;

        for (bank = 0; bank < NR_BANKS; ++bank) {
                if (!(per_cpu(bank_map, cpu) & (1 << bank)))
                        continue;
                threshold_remove_bank(cpu, bank);
        }
}

/* get notified when a cpu comes on/off */
static void __cpuinit
amd_64_threshold_cpu_callback(unsigned long action, unsigned int cpu)
{
        switch (action) {
        case CPU_ONLINE:
        case CPU_ONLINE_FROZEN:
                threshold_create_device(cpu);
                break;
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
                threshold_remove_device(cpu);
                break;
        default:
                break;
        }
}

static __init int threshold_init_device(void)
{
        unsigned lcpu = 0;

        /* to hit CPUs online before the notifier is up */
        for_each_online_cpu(lcpu) {
                int err = threshold_create_device(lcpu);

                if (err)
                        return err;
        }
        threshold_cpu_callback = amd_64_threshold_cpu_callback;

        return 0;
}
device_initcall(threshold_init_device);