/*
 * edac_device.c
 * (C) 2007 www.douglaskthompson.com
 *
 * This file may be distributed under the terms of the
 * GNU General Public License.
 *
 * Written by Doug Thompson <norsk5@xmission.com>
 *
 * edac_device API implementation
 * 19 Jan 2007
 */

#include <asm/page.h>
#include <linux/uaccess.h>
#include <linux/ctype.h>
#include <linux/highmem.h>
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/sysctl.h>
#include <linux/timer.h>

#include "edac_device.h"
#include "edac_module.h"

/* lock for the list: 'edac_device_list', manipulation of this list
 * is protected by the 'device_ctls_mutex' lock
 */
static DEFINE_MUTEX(device_ctls_mutex);
static LIST_HEAD(edac_device_list);

/* Default workqueue processing interval on this instance, in msecs */
#define DEFAULT_POLL_INTERVAL 1000

#ifdef CONFIG_EDAC_DEBUG
static void edac_device_dump_device(struct edac_device_ctl_info *edac_dev)
{
        edac_dbg(3, "\tedac_dev = %p dev_idx=%d\n",
                 edac_dev, edac_dev->dev_idx);
        edac_dbg(4, "\tedac_dev->edac_check = %p\n", edac_dev->edac_check);
        edac_dbg(3, "\tdev = %p\n", edac_dev->dev);
        edac_dbg(3, "\tmod_name:ctl_name = %s:%s\n",
                 edac_dev->mod_name, edac_dev->ctl_name);
        edac_dbg(3, "\tpvt_info = %p\n\n", edac_dev->pvt_info);
}
#endif                          /* CONFIG_EDAC_DEBUG */

/*
 * @off_val: zero, 1, or other based offset
 */
struct edac_device_ctl_info *
edac_device_alloc_ctl_info(unsigned pvt_sz, char *dev_name, unsigned nr_instances,
                           char *blk_name, unsigned nr_blocks, unsigned off_val,
                           int device_index)
{
        struct edac_device_block *dev_blk, *blk_p, *blk;
        struct edac_device_instance *dev_inst, *inst;
        struct edac_device_ctl_info *dev_ctl;
        unsigned instance, block;
        void *pvt;
        int err;

        edac_dbg(4, "instances=%d blocks=%d\n", nr_instances, nr_blocks);

        dev_ctl = kzalloc_obj(struct edac_device_ctl_info);
        if (!dev_ctl)
                return NULL;

        dev_inst = kzalloc_objs(struct edac_device_instance, nr_instances);
        if (!dev_inst)
                goto free;

        dev_ctl->instances = dev_inst;

        dev_blk = kzalloc_objs(struct edac_device_block,
                               nr_instances * nr_blocks);
        if (!dev_blk)
                goto free;

        dev_ctl->blocks = dev_blk;

        if (pvt_sz) {
                pvt = kzalloc(pvt_sz, GFP_KERNEL);
                if (!pvt)
                        goto free;

                dev_ctl->pvt_info = pvt;
        }

        dev_ctl->dev_idx        = device_index;
        dev_ctl->nr_instances   = nr_instances;

        /* Default logging of CEs and UEs */
        dev_ctl->log_ce = 1;
        dev_ctl->log_ue = 1;

        /* Name of this edac device */
        snprintf(dev_ctl->name, sizeof(dev_ctl->name),"%s", dev_name);

        /* Initialize every Instance */
        for (instance = 0; instance < nr_instances; instance++) {
                inst = &dev_inst[instance];
                inst->ctl = dev_ctl;
                inst->nr_blocks = nr_blocks;
                blk_p = &dev_blk[instance * nr_blocks];
                inst->blocks = blk_p;

                /* name of this instance */
                snprintf(inst->name, sizeof(inst->name), "%s%u", dev_name, instance);

                /* Initialize every block in each instance */
                for (block = 0; block < nr_blocks; block++) {
                        blk = &blk_p[block];
                        blk->instance = inst;
                        snprintf(blk->name, sizeof(blk->name),
                                 "%s%d", blk_name, block + off_val);

                        edac_dbg(4, "instance=%d inst_p=%p block=#%d block_p=%p name='%s'\n",
                                 instance, inst, block, blk, blk->name);
                }
        }

        /* Mark this instance as merely ALLOCATED */
        dev_ctl->op_state = OP_ALLOC;

        /*
         * Initialize the 'root' kobj for the edac_device controller
         */
        err = edac_device_register_sysfs_main_kobj(dev_ctl);
        if (err)
                goto free;

        /* at this point, the root kobj is valid, and in order to
         * 'free' the object, then the function:
         *      edac_device_unregister_sysfs_main_kobj() must be called
         * which will perform kobj unregistration and the actual free
         * will occur during the kobject callback operation
         */

        return dev_ctl;

free:
        __edac_device_free_ctl_info(dev_ctl);

        return NULL;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_ctl_info);

void edac_device_free_ctl_info(struct edac_device_ctl_info *ctl_info)
{
        edac_device_unregister_sysfs_main_kobj(ctl_info);
}
EXPORT_SYMBOL_GPL(edac_device_free_ctl_info);

/*
 * find_edac_device_by_dev
 *      scans the edac_device list for a specific 'struct device *'
 *
 *      lock to be held prior to call:  device_ctls_mutex
 *
 *      Return:
 *              pointer to control structure managing 'dev'
 *              NULL if not found on list
 */
static struct edac_device_ctl_info *find_edac_device_by_dev(struct device *dev)
{
        struct edac_device_ctl_info *edac_dev;
        struct list_head *item;

        edac_dbg(0, "\n");

        list_for_each(item, &edac_device_list) {
                edac_dev = list_entry(item, struct edac_device_ctl_info, link);

                if (edac_dev->dev == dev)
                        return edac_dev;
        }

        return NULL;
}

/*
 * add_edac_dev_to_global_list
 *      Before calling this function, caller must
 *      assign a unique value to edac_dev->dev_idx.
 *
 *      lock to be held prior to call:  device_ctls_mutex
 *
 *      Return:
 *              0 on success
 *              1 on failure.
 */
static int add_edac_dev_to_global_list(struct edac_device_ctl_info *edac_dev)
{
        struct list_head *item, *insert_before;
        struct edac_device_ctl_info *rover;

        insert_before = &edac_device_list;

        /* Determine if already on the list */
        rover = find_edac_device_by_dev(edac_dev->dev);
        if (unlikely(rover != NULL))
                goto fail0;

        /* Insert in ascending order by 'dev_idx', so find position */
        list_for_each(item, &edac_device_list) {
                rover = list_entry(item, struct edac_device_ctl_info, link);

                if (rover->dev_idx >= edac_dev->dev_idx) {
                        if (unlikely(rover->dev_idx == edac_dev->dev_idx))
                                goto fail1;

                        insert_before = item;
                        break;
                }
        }

        list_add_tail_rcu(&edac_dev->link, insert_before);
        return 0;

fail0:
        edac_printk(KERN_WARNING, EDAC_MC,
                        "%s (%s) %s %s already assigned %d\n",
                        dev_name(rover->dev), edac_dev_name(rover),
                        rover->mod_name, rover->ctl_name, rover->dev_idx);
        return 1;

fail1:
        edac_printk(KERN_WARNING, EDAC_MC,
                        "bug in low-level driver: attempt to assign\n"
                        "    duplicate dev_idx %d in %s()\n", rover->dev_idx,
                        __func__);
        return 1;
}

/*
 * del_edac_device_from_global_list
 */
static void del_edac_device_from_global_list(struct edac_device_ctl_info
                                                *edac_device)
{
        list_del_rcu(&edac_device->link);

        /* these are for safe removal of devices from global list while
         * NMI handlers may be traversing list
         */
        synchronize_rcu();
        INIT_LIST_HEAD(&edac_device->link);
}

/*
 * edac_device_workq_function
 *      performs the operation scheduled by a workq request
 *
 *      this workq is embedded within an edac_device_ctl_info
 *      structure, that needs to be polled for possible error events.
 *
 *      This operation is to acquire the list mutex lock
 *      (thus preventing insertation or deletion)
 *      and then call the device's poll function IFF this device is
 *      running polled and there is a poll function defined.
 */
static void edac_device_workq_function(struct work_struct *work_req)
{
        struct delayed_work *d_work = to_delayed_work(work_req);
        struct edac_device_ctl_info *edac_dev = to_edac_device_ctl_work(d_work);

        mutex_lock(&device_ctls_mutex);

        /* If we are being removed, bail out immediately */
        if (edac_dev->op_state == OP_OFFLINE) {
                mutex_unlock(&device_ctls_mutex);
                return;
        }

        /* Only poll controllers that are running polled and have a check */
        if ((edac_dev->op_state == OP_RUNNING_POLL) &&
                (edac_dev->edac_check != NULL)) {
                        edac_dev->edac_check(edac_dev);
        }

        mutex_unlock(&device_ctls_mutex);

        /* Reschedule the workq for the next time period to start again
         * if the number of msec is for 1 sec, then adjust to the next
         * whole one second to save timers firing all over the period
         * between integral seconds
         */
        if (edac_dev->poll_msec == DEFAULT_POLL_INTERVAL)
                edac_queue_work(&edac_dev->work, round_jiffies_relative(edac_dev->delay));
        else
                edac_queue_work(&edac_dev->work, edac_dev->delay);
}

/*
 * edac_device_workq_setup
 *      initialize a workq item for this edac_device instance
 *      passing in the new delay period in msec
 */
static void edac_device_workq_setup(struct edac_device_ctl_info *edac_dev,
                                    unsigned msec)
{
        edac_dbg(0, "\n");

        /* take the arg 'msec' and set it into the control structure
         * to used in the time period calculation
         * then calc the number of jiffies that represents
         */
        edac_dev->poll_msec = msec;
        edac_dev->delay = msecs_to_jiffies(msec);

        INIT_DELAYED_WORK(&edac_dev->work, edac_device_workq_function);

        /* optimize here for the 1 second case, which will be normal value, to
         * fire ON the 1 second time event. This helps reduce all sorts of
         * timers firing on sub-second basis, while they are happy
         * to fire together on the 1 second exactly
         */
        if (edac_dev->poll_msec == DEFAULT_POLL_INTERVAL)
                edac_queue_work(&edac_dev->work, round_jiffies_relative(edac_dev->delay));
        else
                edac_queue_work(&edac_dev->work, edac_dev->delay);
}

/*
 * edac_device_workq_teardown
 *      stop the workq processing on this edac_dev
 */
static void edac_device_workq_teardown(struct edac_device_ctl_info *edac_dev)
{
        if (!edac_dev->edac_check)
                return;

        edac_dev->op_state = OP_OFFLINE;

        edac_stop_work(&edac_dev->work);
}

/*
 * edac_device_reset_delay_period
 *
 *      need to stop any outstanding workq queued up at this time
 *      because we will be resetting the sleep time.
 *      Then restart the workq on the new delay
 */
void edac_device_reset_delay_period(struct edac_device_ctl_info *edac_dev,
                                    unsigned long msec)
{
        edac_dev->poll_msec = msec;
        edac_dev->delay     = msecs_to_jiffies(msec);

        /* See comment in edac_device_workq_setup() above */
        if (edac_dev->poll_msec == DEFAULT_POLL_INTERVAL)
                edac_mod_work(&edac_dev->work, round_jiffies_relative(edac_dev->delay));
        else
                edac_mod_work(&edac_dev->work, edac_dev->delay);
}

int edac_device_alloc_index(void)
{
        static atomic_t device_indexes = ATOMIC_INIT(0);

        return atomic_inc_return(&device_indexes) - 1;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_index);

int edac_device_add_device(struct edac_device_ctl_info *edac_dev)
{
        edac_dbg(0, "\n");

#ifdef CONFIG_EDAC_DEBUG
        if (edac_debug_level >= 3)
                edac_device_dump_device(edac_dev);
#endif
        mutex_lock(&device_ctls_mutex);

        if (add_edac_dev_to_global_list(edac_dev))
                goto fail0;

        /* set load time so that error rate can be tracked */
        edac_dev->start_time = jiffies;

        /* create this instance's sysfs entries */
        if (edac_device_create_sysfs(edac_dev)) {
                edac_device_printk(edac_dev, KERN_WARNING,
                                        "failed to create sysfs device\n");
                goto fail1;
        }

        /* If there IS a check routine, then we are running POLLED */
        if (edac_dev->edac_check != NULL) {
                /* This instance is NOW RUNNING */
                edac_dev->op_state = OP_RUNNING_POLL;

                edac_device_workq_setup(edac_dev, edac_dev->poll_msec ?: DEFAULT_POLL_INTERVAL);
        } else {
                edac_dev->op_state = OP_RUNNING_INTERRUPT;
        }

        /* Report action taken */
        edac_device_printk(edac_dev, KERN_INFO,
                "Giving out device to module %s controller %s: DEV %s (%s)\n",
                edac_dev->mod_name, edac_dev->ctl_name, edac_dev->dev_name,
                edac_op_state_to_string(edac_dev->op_state));

        mutex_unlock(&device_ctls_mutex);
        return 0;

fail1:
        /* Some error, so remove the entry from the lsit */
        del_edac_device_from_global_list(edac_dev);

fail0:
        mutex_unlock(&device_ctls_mutex);
        return 1;
}
EXPORT_SYMBOL_GPL(edac_device_add_device);

struct edac_device_ctl_info *edac_device_del_device(struct device *dev)
{
        struct edac_device_ctl_info *edac_dev;

        edac_dbg(0, "\n");

        mutex_lock(&device_ctls_mutex);

        /* Find the structure on the list, if not there, then leave */
        edac_dev = find_edac_device_by_dev(dev);
        if (edac_dev == NULL) {
                mutex_unlock(&device_ctls_mutex);
                return NULL;
        }

        /* mark this instance as OFFLINE */
        edac_dev->op_state = OP_OFFLINE;

        /* deregister from global list */
        del_edac_device_from_global_list(edac_dev);

        mutex_unlock(&device_ctls_mutex);

        /* clear workq processing on this instance */
        edac_device_workq_teardown(edac_dev);

        /* Tear down the sysfs entries for this instance */
        edac_device_remove_sysfs(edac_dev);

        edac_printk(KERN_INFO, EDAC_MC,
                "Removed device %d for %s %s: DEV %s\n",
                edac_dev->dev_idx,
                edac_dev->mod_name, edac_dev->ctl_name, edac_dev_name(edac_dev));

        return edac_dev;
}
EXPORT_SYMBOL_GPL(edac_device_del_device);

static inline int edac_device_get_log_ce(struct edac_device_ctl_info *edac_dev)
{
        return edac_dev->log_ce;
}

static inline int edac_device_get_log_ue(struct edac_device_ctl_info *edac_dev)
{
        return edac_dev->log_ue;
}

static inline int edac_device_get_panic_on_ue(struct edac_device_ctl_info
                                        *edac_dev)
{
        return edac_dev->panic_on_ue;
}

void edac_device_handle_ce_count(struct edac_device_ctl_info *edac_dev,
                                 unsigned int count, int inst_nr, int block_nr,
                                 const char *msg)
{
        struct edac_device_instance *instance;
        struct edac_device_block *block = NULL;

        if (!count)
                return;

        if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: 'instance' out of range "
                                "(%d >= %d)\n", inst_nr,
                                edac_dev->nr_instances);
                return;
        }

        instance = edac_dev->instances + inst_nr;

        if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: instance %d 'block' "
                                "out of range (%d >= %d)\n",
                                inst_nr, block_nr,
                                instance->nr_blocks);
                return;
        }

        if (instance->nr_blocks > 0) {
                block = instance->blocks + block_nr;
                block->counters.ce_count += count;
        }

        /* Propagate the count up the 'totals' tree */
        instance->counters.ce_count += count;
        edac_dev->counters.ce_count += count;

        if (edac_device_get_log_ce(edac_dev))
                edac_device_printk(edac_dev, KERN_WARNING,
                                   "CE: %s instance: %s block: %s count: %d '%s'\n",
                                   edac_dev->ctl_name, instance->name,
                                   block ? block->name : "N/A", count, msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ce_count);

void edac_device_handle_ue_count(struct edac_device_ctl_info *edac_dev,
                                 unsigned int count, int inst_nr, int block_nr,
                                 const char *msg)
{
        struct edac_device_instance *instance;
        struct edac_device_block *block = NULL;

        if (!count)
                return;

        if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: 'instance' out of range "
                                "(%d >= %d)\n", inst_nr,
                                edac_dev->nr_instances);
                return;
        }

        instance = edac_dev->instances + inst_nr;

        if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
                edac_device_printk(edac_dev, KERN_ERR,
                                "INTERNAL ERROR: instance %d 'block' "
                                "out of range (%d >= %d)\n",
                                inst_nr, block_nr,
                                instance->nr_blocks);
                return;
        }

        if (instance->nr_blocks > 0) {
                block = instance->blocks + block_nr;
                block->counters.ue_count += count;
        }

        /* Propagate the count up the 'totals' tree */
        instance->counters.ue_count += count;
        edac_dev->counters.ue_count += count;

        if (edac_device_get_log_ue(edac_dev))
                edac_device_printk(edac_dev, KERN_EMERG,
                                   "UE: %s instance: %s block: %s count: %d '%s'\n",
                                   edac_dev->ctl_name, instance->name,
                                   block ? block->name : "N/A", count, msg);

        if (edac_device_get_panic_on_ue(edac_dev))
                panic("EDAC %s: UE instance: %s block %s count: %d '%s'\n",
                      edac_dev->ctl_name, instance->name,
                      block ? block->name : "N/A", count, msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ue_count);

static void edac_dev_release(struct device *dev)
{
        struct edac_dev_feat_ctx *ctx = container_of(dev, struct edac_dev_feat_ctx, dev);

        kfree(ctx->mem_repair);
        kfree(ctx->scrub);
        kfree(ctx->dev.groups);
        kfree(ctx);
}

static const struct device_type edac_dev_type = {
        .name = "edac_dev",
        .release = edac_dev_release,
};

static void edac_dev_unreg(void *data)
{
        device_unregister(data);
}

/**
 * edac_dev_register - register device for RAS features with EDAC
 * @parent: parent device.
 * @name: name for the folder in the /sys/bus/edac/devices/,
 *        which is derived from the parent device.
 *        For e.g. /sys/bus/edac/devices/cxl_mem0/
 * @private: parent driver's data to store in the context if any.
 * @num_features: number of RAS features to register.
 * @ras_features: list of RAS features to register.
 *
 * Return:
 *  * %0       - Success.
 *  * %-EINVAL - Invalid parameters passed.
 *  * %-ENOMEM - Dynamic memory allocation failed.
 *
 */
int edac_dev_register(struct device *parent, char *name,
                      void *private, int num_features,
                      const struct edac_dev_feature *ras_features)
{
        const struct attribute_group **ras_attr_groups;
        struct edac_dev_data *dev_data;
        struct edac_dev_feat_ctx *ctx;
        int mem_repair_cnt = 0;
        int attr_gcnt = 0;
        int ret = -ENOMEM;
        int scrub_cnt = 0;
        int feat;

        if (!parent || !name || !num_features || !ras_features)
                return -EINVAL;

        /* Double parse to make space for attributes */
        for (feat = 0; feat < num_features; feat++) {
                switch (ras_features[feat].ft_type) {
                case RAS_FEAT_SCRUB:
                        attr_gcnt++;
                        scrub_cnt++;
                        break;
                case RAS_FEAT_ECS:
                        attr_gcnt += ras_features[feat].ecs_info.num_media_frus;
                        break;
                case RAS_FEAT_MEM_REPAIR:
                        attr_gcnt++;
                        mem_repair_cnt++;
                        break;
                default:
                        return -EINVAL;
                }
        }

        ctx = kzalloc_obj(*ctx);
        if (!ctx)
                return -ENOMEM;

        ras_attr_groups = kzalloc_objs(*ras_attr_groups, attr_gcnt + 1);
        if (!ras_attr_groups)
                goto ctx_free;

        if (scrub_cnt) {
                ctx->scrub = kzalloc_objs(*ctx->scrub, scrub_cnt);
                if (!ctx->scrub)
                        goto groups_free;
        }

        if (mem_repair_cnt) {
                ctx->mem_repair = kzalloc_objs(*ctx->mem_repair, mem_repair_cnt);
                if (!ctx->mem_repair)
                        goto data_mem_free;
        }

        attr_gcnt = 0;
        scrub_cnt = 0;
        mem_repair_cnt = 0;
        for (feat = 0; feat < num_features; feat++, ras_features++) {
                switch (ras_features->ft_type) {
                case RAS_FEAT_SCRUB:
                        if (!ras_features->scrub_ops || scrub_cnt != ras_features->instance) {
                                ret = -EINVAL;
                                goto data_mem_free;
                        }

                        dev_data = &ctx->scrub[scrub_cnt];
                        dev_data->instance = scrub_cnt;
                        dev_data->scrub_ops = ras_features->scrub_ops;
                        dev_data->private = ras_features->ctx;
                        ret = edac_scrub_get_desc(parent, &ras_attr_groups[attr_gcnt],
                                                  ras_features->instance);
                        if (ret)
                                goto data_mem_free;

                        scrub_cnt++;
                        attr_gcnt++;
                        break;
                case RAS_FEAT_ECS:
                        if (!ras_features->ecs_ops) {
                                ret = -EINVAL;
                                goto data_mem_free;
                        }

                        dev_data = &ctx->ecs;
                        dev_data->ecs_ops = ras_features->ecs_ops;
                        dev_data->private = ras_features->ctx;
                        ret = edac_ecs_get_desc(parent, &ras_attr_groups[attr_gcnt],
                                                ras_features->ecs_info.num_media_frus);
                        if (ret)
                                goto data_mem_free;

                        attr_gcnt += ras_features->ecs_info.num_media_frus;
                        break;
                case RAS_FEAT_MEM_REPAIR:
                        if (!ras_features->mem_repair_ops ||
                            mem_repair_cnt != ras_features->instance) {
                                ret = -EINVAL;
                                goto data_mem_free;
                        }

                        dev_data = &ctx->mem_repair[mem_repair_cnt];
                        dev_data->instance = mem_repair_cnt;
                        dev_data->mem_repair_ops = ras_features->mem_repair_ops;
                        dev_data->private = ras_features->ctx;
                        ret = edac_mem_repair_get_desc(parent, &ras_attr_groups[attr_gcnt],
                                                       ras_features->instance);
                        if (ret)
                                goto data_mem_free;

                        mem_repair_cnt++;
                        attr_gcnt++;
                        break;
                default:
                        ret = -EINVAL;
                        goto data_mem_free;
                }
        }

        ctx->dev.parent = parent;
        ctx->dev.bus = edac_get_sysfs_subsys();
        ctx->dev.type = &edac_dev_type;
        ctx->dev.groups = ras_attr_groups;
        ctx->private = private;
        dev_set_drvdata(&ctx->dev, ctx);

        ret = dev_set_name(&ctx->dev, "%s", name);
        if (ret)
                goto data_mem_free;

        ret = device_register(&ctx->dev);
        if (ret) {
                put_device(&ctx->dev);
                return ret;
        }

        return devm_add_action_or_reset(parent, edac_dev_unreg, &ctx->dev);

data_mem_free:
        kfree(ctx->mem_repair);
        kfree(ctx->scrub);
groups_free:
        kfree(ras_attr_groups);
ctx_free:
        kfree(ctx);
        return ret;
}
EXPORT_SYMBOL_GPL(edac_dev_register);