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edac_device.c

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

#include "edac_core.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 struct list_head edac_device_list = LIST_HEAD_INIT(edac_device_list);

#ifdef CONFIG_EDAC_DEBUG
static void edac_device_dump_device(struct edac_device_ctl_info *edac_dev)
{
      debugf3("\tedac_dev = %p dev_idx=%d \n", edac_dev, edac_dev->dev_idx);
      debugf4("\tedac_dev->edac_check = %p\n", edac_dev->edac_check);
      debugf3("\tdev = %p\n", edac_dev->dev);
      debugf3("\tmod_name:ctl_name = %s:%s\n",
            edac_dev->mod_name, edac_dev->ctl_name);
      debugf3("\tpvt_info = %p\n\n", edac_dev->pvt_info);
}
#endif                        /* CONFIG_EDAC_DEBUG */


/*
 * edac_device_alloc_ctl_info()
 *    Allocate a new edac device control info structure
 *
 *    The control structure is allocated in complete chunk
 *    from the OS. It is in turn sub allocated to the
 *    various objects that compose the struture
 *
 *    The structure has a 'nr_instance' array within itself.
 *    Each instance represents a major component
 *          Example:  L1 cache and L2 cache are 2 instance components
 *
 *    Within each instance is an array of 'nr_blocks' blockoffsets
 */
struct edac_device_ctl_info *edac_device_alloc_ctl_info(
      unsigned sz_private,
      char *edac_device_name, unsigned nr_instances,
      char *edac_block_name, unsigned nr_blocks,
      unsigned offset_value,        /* zero, 1, or other based offset */
      struct edac_dev_sysfs_block_attribute *attrib_spec, unsigned nr_attrib,
      int device_index)
{
      struct edac_device_ctl_info *dev_ctl;
      struct edac_device_instance *dev_inst, *inst;
      struct edac_device_block *dev_blk, *blk_p, *blk;
      struct edac_dev_sysfs_block_attribute *dev_attrib, *attrib_p, *attrib;
      unsigned total_size;
      unsigned count;
      unsigned instance, block, attr;
      void *pvt;
      int err;

      debugf4("%s() instances=%d blocks=%d\n",
            __func__, nr_instances, nr_blocks);

      /* Calculate the size of memory we need to allocate AND
       * determine the offsets of the various item arrays
       * (instance,block,attrib) from the start of an  allocated structure.
       * We want the alignment of each item  (instance,block,attrib)
       * to be at least as stringent as what the compiler would
       * provide if we could simply hardcode everything into a single struct.
       */
      dev_ctl = (struct edac_device_ctl_info *)NULL;

      /* Calc the 'end' offset past end of ONE ctl_info structure
       * which will become the start of the 'instance' array
       */
      dev_inst = edac_align_ptr(&dev_ctl[1], sizeof(*dev_inst));

      /* Calc the 'end' offset past the instance array within the ctl_info
       * which will become the start of the block array
       */
      dev_blk = edac_align_ptr(&dev_inst[nr_instances], sizeof(*dev_blk));

      /* Calc the 'end' offset past the dev_blk array
       * which will become the start of the attrib array, if any.
       */
      count = nr_instances * nr_blocks;
      dev_attrib = edac_align_ptr(&dev_blk[count], sizeof(*dev_attrib));

      /* Check for case of when an attribute array is specified */
      if (nr_attrib > 0) {
            /* calc how many nr_attrib we need */
            count *= nr_attrib;

            /* Calc the 'end' offset past the attributes array */
            pvt = edac_align_ptr(&dev_attrib[count], sz_private);
      } else {
            /* no attribute array specificed */
            pvt = edac_align_ptr(dev_attrib, sz_private);
      }

      /* 'pvt' now points to where the private data area is.
       * At this point 'pvt' (like dev_inst,dev_blk and dev_attrib)
       * is baselined at ZERO
       */
      total_size = ((unsigned long)pvt) + sz_private;

      /* Allocate the amount of memory for the set of control structures */
      dev_ctl = kzalloc(total_size, GFP_KERNEL);
      if (dev_ctl == NULL)
            return NULL;

      /* Adjust pointers so they point within the actual memory we
       * just allocated rather than an imaginary chunk of memory
       * located at address 0.
       * 'dev_ctl' points to REAL memory, while the others are
       * ZERO based and thus need to be adjusted to point within
       * the allocated memory.
       */
      dev_inst = (struct edac_device_instance *)
            (((char *)dev_ctl) + ((unsigned long)dev_inst));
      dev_blk = (struct edac_device_block *)
            (((char *)dev_ctl) + ((unsigned long)dev_blk));
      dev_attrib = (struct edac_dev_sysfs_block_attribute *)
            (((char *)dev_ctl) + ((unsigned long)dev_attrib));
      pvt = sz_private ? (((char *)dev_ctl) + ((unsigned long)pvt)) : NULL;

      /* Begin storing the information into the control info structure */
      dev_ctl->dev_idx = device_index;
      dev_ctl->nr_instances = nr_instances;
      dev_ctl->instances = dev_inst;
      dev_ctl->pvt_info = pvt;

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

      debugf4("%s() edac_dev=%p next after end=%p\n",
            __func__, dev_ctl, pvt + sz_private );

      /* 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", edac_device_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", edac_block_name, block+offset_value);

                  debugf4("%s() instance=%d inst_p=%p block=#%d "
                        "block_p=%p name='%s'\n",
                        __func__, instance, inst, block,
                        blk, blk->name);

                  /* if there are NO attributes OR no attribute pointer
                   * then continue on to next block iteration
                   */
                  if ((nr_attrib == 0) || (attrib_spec == NULL))
                        continue;

                  /* setup the attribute array for this block */
                  blk->nr_attribs = nr_attrib;
                  attrib_p = &dev_attrib[block*nr_instances*nr_attrib];
                  blk->block_attributes = attrib_p;

                  debugf4("%s() THIS BLOCK_ATTRIB=%p\n",
                        __func__, blk->block_attributes);

                  /* Initialize every user specified attribute in this
                   * block with the data the caller passed in
                   * Each block gets its own copy of pointers,
                   * and its unique 'value'
                   */
                  for (attr = 0; attr < nr_attrib; attr++) {
                        attrib = &attrib_p[attr];

                        /* populate the unique per attrib
                         * with the code pointers and info
                         */
                        attrib->attr = attrib_spec[attr].attr;
                        attrib->show = attrib_spec[attr].show;
                        attrib->store = attrib_spec[attr].store;

                        attrib->block = blk;    /* up link */

                        debugf4("%s() alloc-attrib=%p attrib_name='%s' "
                              "attrib-spec=%p spec-name=%s\n",
                              __func__, attrib, attrib->attr.name,
                              &attrib_spec[attr],
                              attrib_spec[attr].attr.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) {
            kfree(dev_ctl);
            return NULL;
      }

      /* 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;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_ctl_info);

/*
 * edac_device_free_ctl_info()
 *    frees the memory allocated by the edac_device_alloc_ctl_info()
 *    function
 */
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;

      debugf0("%s()\n", __func__);

      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",
                  rover->dev->bus_id, 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;
}

/*
 * complete_edac_device_list_del
 *
 *    callback function when reference count is zero
 */
static void complete_edac_device_list_del(struct rcu_head *head)
{
      struct edac_device_ctl_info *edac_dev;

      edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
      INIT_LIST_HEAD(&edac_dev->link);
      complete(&edac_dev->removal_complete);
}

/*
 * del_edac_device_from_global_list
 *
 *    remove the RCU, setup for a callback call,
 *    then wait for the callback to occur
 */
static void del_edac_device_from_global_list(struct edac_device_ctl_info
                                    *edac_device)
{
      list_del_rcu(&edac_device->link);

      init_completion(&edac_device->removal_complete);
      call_rcu(&edac_device->rcu, complete_edac_device_list_del);
      wait_for_completion(&edac_device->removal_complete);
}

/**
 * edac_device_find
 *    Search for a edac_device_ctl_info structure whose index is 'idx'.
 *
 * If found, return a pointer to the structure.
 * Else return NULL.
 *
 * Caller must hold device_ctls_mutex.
 */
struct edac_device_ctl_info *edac_device_find(int idx)
{
      struct list_head *item;
      struct edac_device_ctl_info *edac_dev;

      /* Iterate over list, looking for exact match of ID */
      list_for_each(item, &edac_device_list) {
            edac_dev = list_entry(item, struct edac_device_ctl_info, link);

            if (edac_dev->dev_idx >= idx) {
                  if (edac_dev->dev_idx == idx)
                        return edac_dev;

                  /* not on list, so terminate early */
                  break;
            }
      }

      return NULL;
}
EXPORT_SYMBOL_GPL(edac_device_find);

/*
 * 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 = (struct delayed_work *)work_req;
      struct edac_device_ctl_info *edac_dev = to_edac_device_ctl_work(d_work);

      mutex_lock(&device_ctls_mutex);

      /* 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 fireing all over the period
       * between integral seconds
       */
      if (edac_dev->poll_msec == 1000)
            queue_delayed_work(edac_workqueue, &edac_dev->work,
                        round_jiffies(edac_dev->delay));
      else
            queue_delayed_work(edac_workqueue, &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
 */
void edac_device_workq_setup(struct edac_device_ctl_info *edac_dev,
                        unsigned msec)
{
      debugf0("%s()\n", __func__);

      /* 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 == 1000)
            queue_delayed_work(edac_workqueue, &edac_dev->work,
                        round_jiffies(edac_dev->delay));
      else
            queue_delayed_work(edac_workqueue, &edac_dev->work,
                        edac_dev->delay);
}

/*
 * edac_device_workq_teardown
 *    stop the workq processing on this edac_dev
 */
void edac_device_workq_teardown(struct edac_device_ctl_info *edac_dev)
{
      int status;

      status = cancel_delayed_work(&edac_dev->work);
      if (status == 0) {
            /* workq instance might be running, wait for it */
            flush_workqueue(edac_workqueue);
      }
}

/*
 * 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 value)
{
      /* cancel the current workq request, without the mutex lock */
      edac_device_workq_teardown(edac_dev);

      /* acquire the mutex before doing the workq setup */
      mutex_lock(&device_ctls_mutex);

      /* restart the workq request, with new delay value */
      edac_device_workq_setup(edac_dev, value);

      mutex_unlock(&device_ctls_mutex);
}

/**
 * edac_device_add_device: Insert the 'edac_dev' structure into the
 * edac_device global list and create sysfs entries associated with
 * edac_device structure.
 * @edac_device: pointer to the edac_device structure to be added to the list
 * 'edac_device' structure.
 *
 * Return:
 *    0     Success
 *    !0    Failure
 */
int edac_device_add_device(struct edac_device_ctl_info *edac_dev)
{
      debugf0("%s()\n", __func__);

#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;

            /*
             * enable workq processing on this instance,
             * default = 1000 msec
             */
            edac_device_workq_setup(edac_dev, 1000);
      } 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,
                        dev_name(edac_dev),
                        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);

/**
 * edac_device_del_device:
 *    Remove sysfs entries for specified edac_device structure and
 *    then remove edac_device structure from global list
 *
 * @pdev:
 *    Pointer to 'struct device' representing edac_device
 *    structure to remove.
 *
 * Return:
 *    Pointer to removed edac_device structure,
 *    OR NULL if device not found.
 */
struct edac_device_ctl_info *edac_device_del_device(struct device *dev)
{
      struct edac_device_ctl_info *edac_dev;

      debugf0("%s()\n", __func__);

      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;

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

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

      mutex_unlock(&device_ctls_mutex);

      /* 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, 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;
}

/*
 * edac_device_handle_ce
 *    perform a common output and handling of an 'edac_dev' CE event
 */
void edac_device_handle_ce(struct edac_device_ctl_info *edac_dev,
                  int inst_nr, int block_nr, const char *msg)
{
      struct edac_device_instance *instance;
      struct edac_device_block *block = NULL;

      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++;
      }

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

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

/*
 * edac_device_handle_ue
 *    perform a common output and handling of an 'edac_dev' UE event
 */
void edac_device_handle_ue(struct edac_device_ctl_info *edac_dev,
                  int inst_nr, int block_nr, const char *msg)
{
      struct edac_device_instance *instance;
      struct edac_device_block *block = NULL;

      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++;
      }

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

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

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

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