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edac_pci.c

/*
 * EDAC PCI component
 *
 * Author: Dave Jiang <djiang@mvista.com>
 *
 * 2007 (c) MontaVista Software, Inc. This file is licensed under
 * the terms of the GNU General Public License version 2. This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 *
 */
#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/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"

static DEFINE_MUTEX(edac_pci_ctls_mutex);
static struct list_head edac_pci_list = LIST_HEAD_INIT(edac_pci_list);

/*
 * edac_pci_alloc_ctl_info
 *
 *    The alloc() function for the 'edac_pci' control info
 *    structure. The chip driver will allocate one of these for each
 *    edac_pci it is going to control/register with the EDAC CORE.
 */
struct edac_pci_ctl_info *edac_pci_alloc_ctl_info(unsigned int sz_pvt,
                                    const char *edac_pci_name)
{
      struct edac_pci_ctl_info *pci;
      void *pvt;
      unsigned int size;

      debugf1("%s()\n", __func__);

      pci = (struct edac_pci_ctl_info *)0;
      pvt = edac_align_ptr(&pci[1], sz_pvt);
      size = ((unsigned long)pvt) + sz_pvt;

      /* Alloc the needed control struct memory */
      pci = kzalloc(size, GFP_KERNEL);
      if (pci  == NULL)
            return NULL;

      /* Now much private space */
      pvt = sz_pvt ? ((char *)pci) + ((unsigned long)pvt) : NULL;

      pci->pvt_info = pvt;
      pci->op_state = OP_ALLOC;

      snprintf(pci->name, strlen(edac_pci_name) + 1, "%s", edac_pci_name);

      return pci;
}
EXPORT_SYMBOL_GPL(edac_pci_alloc_ctl_info);

/*
 * edac_pci_free_ctl_info()
 *
 *    Last action on the pci control structure.
 *
 *    call the remove sysfs informaton, which will unregister
 *    this control struct's kobj. When that kobj's ref count
 *    goes to zero, its release function will be call and then
 *    kfree() the memory.
 */
void edac_pci_free_ctl_info(struct edac_pci_ctl_info *pci)
{
      debugf1("%s()\n", __func__);

      edac_pci_remove_sysfs(pci);
}
EXPORT_SYMBOL_GPL(edac_pci_free_ctl_info);

/*
 * find_edac_pci_by_dev()
 *    scans the edac_pci list for a specific 'struct device *'
 *
 *    return NULL if not found, or return control struct pointer
 */
static struct edac_pci_ctl_info *find_edac_pci_by_dev(struct device *dev)
{
      struct edac_pci_ctl_info *pci;
      struct list_head *item;

      debugf1("%s()\n", __func__);

      list_for_each(item, &edac_pci_list) {
            pci = list_entry(item, struct edac_pci_ctl_info, link);

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

      return NULL;
}

/*
 * add_edac_pci_to_global_list
 *    Before calling this function, caller must assign a unique value to
 *    edac_dev->pci_idx.
 *    Return:
 *          0 on success
 *          1 on failure
 */
static int add_edac_pci_to_global_list(struct edac_pci_ctl_info *pci)
{
      struct list_head *item, *insert_before;
      struct edac_pci_ctl_info *rover;

      debugf1("%s()\n", __func__);

      insert_before = &edac_pci_list;

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

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

            if (rover->pci_idx >= pci->pci_idx) {
                  if (unlikely(rover->pci_idx == pci->pci_idx))
                        goto fail1;

                  insert_before = item;
                  break;
            }
      }

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

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

fail1:
      edac_printk(KERN_WARNING, EDAC_PCI,
            "but in low-level driver: attempt to assign\n"
            "\tduplicate pci_idx %d in %s()\n", rover->pci_idx,
            __func__);
      return 1;
}

/*
 * complete_edac_pci_list_del
 *
 *    RCU completion callback to indicate item is deleted
 */
static void complete_edac_pci_list_del(struct rcu_head *head)
{
      struct edac_pci_ctl_info *pci;

      pci = container_of(head, struct edac_pci_ctl_info, rcu);
      INIT_LIST_HEAD(&pci->link);
      complete(&pci->complete);
}

/*
 * del_edac_pci_from_global_list
 *
 *    remove the PCI control struct from the global list
 */
static void del_edac_pci_from_global_list(struct edac_pci_ctl_info *pci)
{
      list_del_rcu(&pci->link);
      init_completion(&pci->complete);
      call_rcu(&pci->rcu, complete_edac_pci_list_del);
      wait_for_completion(&pci->complete);
}

/*
 * edac_pci_find()
 *    Search for an edac_pci_ctl_info structure whose index is 'idx'
 *
 * If found, return a pointer to the structure
 * Else return NULL.
 *
 * Caller must hold pci_ctls_mutex.
 */
struct edac_pci_ctl_info *edac_pci_find(int idx)
{
      struct list_head *item;
      struct edac_pci_ctl_info *pci;

      /* Iterage over list, looking for exact match of ID */
      list_for_each(item, &edac_pci_list) {
            pci = list_entry(item, struct edac_pci_ctl_info, link);

            if (pci->pci_idx >= idx) {
                  if (pci->pci_idx == idx)
                        return pci;

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

      return NULL;
}
EXPORT_SYMBOL_GPL(edac_pci_find);

/*
 * edac_pci_workq_function()
 *
 *    periodic function that performs the operation
 *    scheduled by a workq request, for a given PCI control struct
 */
static void edac_pci_workq_function(struct work_struct *work_req)
{
      struct delayed_work *d_work = (struct delayed_work *)work_req;
      struct edac_pci_ctl_info *pci = to_edac_pci_ctl_work(d_work);
      int msec;
      unsigned long delay;

      debugf3("%s() checking\n", __func__);

      mutex_lock(&edac_pci_ctls_mutex);

      if (pci->op_state == OP_RUNNING_POLL) {
            /* we might be in POLL mode, but there may NOT be a poll func
             */
            if ((pci->edac_check != NULL) && edac_pci_get_check_errors())
                  pci->edac_check(pci);

            /* if we are on a one second period, then use round */
            msec = edac_pci_get_poll_msec();
            if (msec == 1000)
                  delay = round_jiffies(msecs_to_jiffies(msec));
            else
                  delay = msecs_to_jiffies(msec);

            /* Reschedule only if we are in POLL mode */
            queue_delayed_work(edac_workqueue, &pci->work, delay);
      }

      mutex_unlock(&edac_pci_ctls_mutex);
}

/*
 * edac_pci_workq_setup()
 *    initialize a workq item for this edac_pci instance
 *    passing in the new delay period in msec
 *
 *    locking model:
 *          called when 'edac_pci_ctls_mutex' is locked
 */
static void edac_pci_workq_setup(struct edac_pci_ctl_info *pci,
                         unsigned int msec)
{
      debugf0("%s()\n", __func__);

      INIT_DELAYED_WORK(&pci->work, edac_pci_workq_function);
      queue_delayed_work(edac_workqueue, &pci->work,
                  msecs_to_jiffies(edac_pci_get_poll_msec()));
}

/*
 * edac_pci_workq_teardown()
 *    stop the workq processing on this edac_pci instance
 */
static void edac_pci_workq_teardown(struct edac_pci_ctl_info *pci)
{
      int status;

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

      status = cancel_delayed_work(&pci->work);
      if (status == 0)
            flush_workqueue(edac_workqueue);
}

/*
 * edac_pci_reset_delay_period
 *
 *    called with a new period value for the workq period
 *    a) stop current workq timer
 *    b) restart workq timer with new value
 */
void edac_pci_reset_delay_period(struct edac_pci_ctl_info *pci,
                         unsigned long value)
{
      debugf0("%s()\n", __func__);

      edac_pci_workq_teardown(pci);

      /* need to lock for the setup */
      mutex_lock(&edac_pci_ctls_mutex);

      edac_pci_workq_setup(pci, value);

      mutex_unlock(&edac_pci_ctls_mutex);
}
EXPORT_SYMBOL_GPL(edac_pci_reset_delay_period);

/*
 * edac_pci_add_device: Insert the 'edac_dev' structure into the
 * edac_pci global list and create sysfs entries associated with
 * edac_pci structure.
 * @pci: pointer to the edac_device structure to be added to the list
 * @edac_idx: A unique numeric identifier to be assigned to the
 * 'edac_pci' structure.
 *
 * Return:
 *      0       Success
 *      !0      Failure
 */
int edac_pci_add_device(struct edac_pci_ctl_info *pci, int edac_idx)
{
      debugf0("%s()\n", __func__);

      pci->pci_idx = edac_idx;
      pci->start_time = jiffies;

      mutex_lock(&edac_pci_ctls_mutex);

      if (add_edac_pci_to_global_list(pci))
            goto fail0;

      if (edac_pci_create_sysfs(pci)) {
            edac_pci_printk(pci, KERN_WARNING,
                        "failed to create sysfs pci\n");
            goto fail1;
      }

      if (pci->edac_check != NULL) {
            pci->op_state = OP_RUNNING_POLL;

            edac_pci_workq_setup(pci, 1000);
      } else {
            pci->op_state = OP_RUNNING_INTERRUPT;
      }

      edac_pci_printk(pci, KERN_INFO,
                  "Giving out device to module '%s' controller '%s':"
                  " DEV '%s' (%s)\n",
                  pci->mod_name,
                  pci->ctl_name,
                  dev_name(pci), edac_op_state_to_string(pci->op_state));

      mutex_unlock(&edac_pci_ctls_mutex);
      return 0;

      /* error unwind stack */
fail1:
      del_edac_pci_from_global_list(pci);
fail0:
      mutex_unlock(&edac_pci_ctls_mutex);
      return 1;
}
EXPORT_SYMBOL_GPL(edac_pci_add_device);

/*
 * edac_pci_del_device()
 *    Remove sysfs entries for specified edac_pci structure and
 *    then remove edac_pci structure from global list
 *
 * @dev:
 *    Pointer to 'struct device' representing edac_pci structure
 *    to remove
 *
 * Return:
 *    Pointer to removed edac_pci structure,
 *    or NULL if device not found
 */
struct edac_pci_ctl_info *edac_pci_del_device(struct device *dev)
{
      struct edac_pci_ctl_info *pci;

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

      mutex_lock(&edac_pci_ctls_mutex);

      /* ensure the control struct is on the global list
       * if not, then leave
       */
      pci = find_edac_pci_by_dev(dev);
      if (pci  == NULL) {
            mutex_unlock(&edac_pci_ctls_mutex);
            return NULL;
      }

      pci->op_state = OP_OFFLINE;

      del_edac_pci_from_global_list(pci);

      mutex_unlock(&edac_pci_ctls_mutex);

      /* stop the workq timer */
      edac_pci_workq_teardown(pci);

      edac_printk(KERN_INFO, EDAC_PCI,
            "Removed device %d for %s %s: DEV %s\n",
            pci->pci_idx, pci->mod_name, pci->ctl_name, dev_name(pci));

      return pci;
}
EXPORT_SYMBOL_GPL(edac_pci_del_device);

/*
 * edac_pci_generic_check
 *
 *    a Generic parity check API
 */
void edac_pci_generic_check(struct edac_pci_ctl_info *pci)
{
      debugf4("%s()\n", __func__);
      edac_pci_do_parity_check();
}

/* free running instance index counter */
static int edac_pci_idx;
#define EDAC_PCI_GENCTL_NAME  "EDAC PCI controller"

struct edac_pci_gen_data {
      int edac_idx;
};

/*
 * edac_pci_create_generic_ctl
 *
 *    A generic constructor for a PCI parity polling device
 *    Some systems have more than one domain of PCI busses.
 *    For systems with one domain, then this API will
 *    provide for a generic poller.
 *
 *    This routine calls the edac_pci_alloc_ctl_info() for
 *    the generic device, with default values
 */
struct edac_pci_ctl_info *edac_pci_create_generic_ctl(struct device *dev,
                                    const char *mod_name)
{
      struct edac_pci_ctl_info *pci;
      struct edac_pci_gen_data *pdata;

      pci = edac_pci_alloc_ctl_info(sizeof(*pdata), EDAC_PCI_GENCTL_NAME);
      if (!pci)
            return NULL;

      pdata = pci->pvt_info;
      pci->dev = dev;
      dev_set_drvdata(pci->dev, pci);
      pci->dev_name = pci_name(to_pci_dev(dev));

      pci->mod_name = mod_name;
      pci->ctl_name = EDAC_PCI_GENCTL_NAME;
      pci->edac_check = edac_pci_generic_check;

      pdata->edac_idx = edac_pci_idx++;

      if (edac_pci_add_device(pci, pdata->edac_idx) > 0) {
            debugf3("%s(): failed edac_pci_add_device()\n", __func__);
            edac_pci_free_ctl_info(pci);
            return NULL;
      }

      return pci;
}
EXPORT_SYMBOL_GPL(edac_pci_create_generic_ctl);

/*
 * edac_pci_release_generic_ctl
 *
 *    The release function of a generic EDAC PCI polling device
 */
void edac_pci_release_generic_ctl(struct edac_pci_ctl_info *pci)
{
      debugf0("%s() pci mod=%s\n", __func__, pci->mod_name);

      edac_pci_del_device(pci->dev);
      edac_pci_free_ctl_info(pci);
}
EXPORT_SYMBOL_GPL(edac_pci_release_generic_ctl);

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