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edac_pci_sysfs.c

/*
 * (C) 2005, 2006 Linux Networx (http://lnxi.com)
 * This file may be distributed under the terms of the
 * GNU General Public License.
 *
 * Written Doug Thompson <norsk5@xmission.com>
 *
 */
#include <linux/module.h>
#include <linux/sysdev.h>
#include <linux/ctype.h>

#include "edac_core.h"
#include "edac_module.h"

/* Turn off this whole feature if PCI is not configured */
#ifdef CONFIG_PCI

#define EDAC_PCI_SYMLINK      "device"

/* data variables exported via sysfs */
static int check_pci_errors;        /* default NO check PCI parity */
static int edac_pci_panic_on_pe;    /* default NO panic on PCI Parity */
static int edac_pci_log_pe = 1;           /* log PCI parity errors */
static int edac_pci_log_npe = 1;    /* log PCI non-parity error errors */
static int edac_pci_poll_msec = 1000;     /* one second workq period */

static atomic_t pci_parity_count = ATOMIC_INIT(0);
static atomic_t pci_nonparity_count = ATOMIC_INIT(0);

static struct kobject edac_pci_top_main_kobj;
static atomic_t edac_pci_sysfs_refcount = ATOMIC_INIT(0);

/* getter functions for the data variables */
int edac_pci_get_check_errors(void)
{
      return check_pci_errors;
}

int edac_pci_get_log_pe(void)
{
      return edac_pci_log_pe;
}

int edac_pci_get_log_npe(void)
{
      return edac_pci_log_npe;
}

int edac_pci_get_panic_on_pe(void)
{
      return edac_pci_panic_on_pe;
}

int edac_pci_get_poll_msec(void)
{
      return edac_pci_poll_msec;
}

/**************************** EDAC PCI sysfs instance *******************/
static ssize_t instance_pe_count_show(struct edac_pci_ctl_info *pci, char *data)
{
      return sprintf(data, "%u\n", atomic_read(&pci->counters.pe_count));
}

static ssize_t instance_npe_count_show(struct edac_pci_ctl_info *pci,
                        char *data)
{
      return sprintf(data, "%u\n", atomic_read(&pci->counters.npe_count));
}

#define to_instance(k) container_of(k, struct edac_pci_ctl_info, kobj)
#define to_instance_attr(a) container_of(a, struct instance_attribute, attr)

/* DEVICE instance kobject release() function */
static void edac_pci_instance_release(struct kobject *kobj)
{
      struct edac_pci_ctl_info *pci;

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

      /* Form pointer to containing struct, the pci control struct */
      pci = to_instance(kobj);

      /* decrement reference count on top main kobj */
      kobject_put(&edac_pci_top_main_kobj);

      kfree(pci); /* Free the control struct */
}

/* instance specific attribute structure */
struct instance_attribute {
      struct attribute attr;
      ssize_t(*show) (struct edac_pci_ctl_info *, char *);
      ssize_t(*store) (struct edac_pci_ctl_info *, const char *, size_t);
};

/* Function to 'show' fields from the edac_pci 'instance' structure */
static ssize_t edac_pci_instance_show(struct kobject *kobj,
                        struct attribute *attr, char *buffer)
{
      struct edac_pci_ctl_info *pci = to_instance(kobj);
      struct instance_attribute *instance_attr = to_instance_attr(attr);

      if (instance_attr->show)
            return instance_attr->show(pci, buffer);
      return -EIO;
}

/* Function to 'store' fields into the edac_pci 'instance' structure */
static ssize_t edac_pci_instance_store(struct kobject *kobj,
                        struct attribute *attr,
                        const char *buffer, size_t count)
{
      struct edac_pci_ctl_info *pci = to_instance(kobj);
      struct instance_attribute *instance_attr = to_instance_attr(attr);

      if (instance_attr->store)
            return instance_attr->store(pci, buffer, count);
      return -EIO;
}

/* fs_ops table */
static struct sysfs_ops pci_instance_ops = {
      .show = edac_pci_instance_show,
      .store = edac_pci_instance_store
};

#define INSTANCE_ATTR(_name, _mode, _show, _store)    \
static struct instance_attribute attr_instance_##_name = {  \
      .attr = {.name = __stringify(_name), .mode = _mode }, \
      .show = _show,                            \
      .store      = _store,                           \
};

INSTANCE_ATTR(pe_count, S_IRUGO, instance_pe_count_show, NULL);
INSTANCE_ATTR(npe_count, S_IRUGO, instance_npe_count_show, NULL);

/* pci instance attributes */
static struct instance_attribute *pci_instance_attr[] = {
      &attr_instance_pe_count,
      &attr_instance_npe_count,
      NULL
};

/* the ktype for a pci instance */
static struct kobj_type ktype_pci_instance = {
      .release = edac_pci_instance_release,
      .sysfs_ops = &pci_instance_ops,
      .default_attrs = (struct attribute **)pci_instance_attr,
};

/*
 * edac_pci_create_instance_kobj
 *
 *    construct one EDAC PCI instance's kobject for use
 */
static int edac_pci_create_instance_kobj(struct edac_pci_ctl_info *pci, int idx)
{
      struct kobject *main_kobj;
      int err;

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

      /* Set the parent and the instance's ktype */
      pci->kobj.parent = &edac_pci_top_main_kobj;
      pci->kobj.ktype = &ktype_pci_instance;

      err = kobject_set_name(&pci->kobj, "pci%d", idx);
      if (err)
            return err;

      /* First bump the ref count on the top main kobj, which will
       * track the number of PCI instances we have, and thus nest
       * properly on keeping the module loaded
       */
      main_kobj = kobject_get(&edac_pci_top_main_kobj);
      if (!main_kobj) {
            err = -ENODEV;
            goto error_out;
      }

      /* And now register this new kobject under the main kobj */
      err = kobject_register(&pci->kobj);
      if (err != 0) {
            debugf2("%s() failed to register instance pci%d\n",
                  __func__, idx);
            kobject_put(&edac_pci_top_main_kobj);
            goto error_out;
      }

      debugf1("%s() Register instance 'pci%d' kobject\n", __func__, idx);

      return 0;

      /* Error unwind statck */
error_out:
      return err;
}

/*
 * edac_pci_unregister_sysfs_instance_kobj
 *
 *    unregister the kobj for the EDAC PCI instance
 */
void edac_pci_unregister_sysfs_instance_kobj(struct edac_pci_ctl_info *pci)
{
      debugf0("%s()\n", __func__);

      /* Unregister the instance kobject and allow its release
       * function release the main reference count and then
       * kfree the memory
       */
      kobject_unregister(&pci->kobj);
}

/***************************** EDAC PCI sysfs root **********************/
#define to_edacpci(k) container_of(k, struct edac_pci_ctl_info, kobj)
#define to_edacpci_attr(a) container_of(a, struct edac_pci_attr, attr)

/* simple show/store functions for attributes */
static ssize_t edac_pci_int_show(void *ptr, char *buffer)
{
      int *value = ptr;
      return sprintf(buffer, "%d\n", *value);
}

static ssize_t edac_pci_int_store(void *ptr, const char *buffer, size_t count)
{
      int *value = ptr;

      if (isdigit(*buffer))
            *value = simple_strtoul(buffer, NULL, 0);

      return count;
}

struct edac_pci_dev_attribute {
      struct attribute attr;
      void *value;
       ssize_t(*show) (void *, char *);
       ssize_t(*store) (void *, const char *, size_t);
};

/* Set of show/store abstract level functions for PCI Parity object */
static ssize_t edac_pci_dev_show(struct kobject *kobj, struct attribute *attr,
                         char *buffer)
{
      struct edac_pci_dev_attribute *edac_pci_dev;
      edac_pci_dev = (struct edac_pci_dev_attribute *)attr;

      if (edac_pci_dev->show)
            return edac_pci_dev->show(edac_pci_dev->value, buffer);
      return -EIO;
}

static ssize_t edac_pci_dev_store(struct kobject *kobj,
                        struct attribute *attr, const char *buffer,
                        size_t count)
{
      struct edac_pci_dev_attribute *edac_pci_dev;
      edac_pci_dev = (struct edac_pci_dev_attribute *)attr;

      if (edac_pci_dev->show)
            return edac_pci_dev->store(edac_pci_dev->value, buffer, count);
      return -EIO;
}

static struct sysfs_ops edac_pci_sysfs_ops = {
      .show = edac_pci_dev_show,
      .store = edac_pci_dev_store
};

#define EDAC_PCI_ATTR(_name,_mode,_show,_store)             \
static struct edac_pci_dev_attribute edac_pci_attr_##_name = {          \
      .attr = {.name = __stringify(_name), .mode = _mode }, \
      .value  = &_name,                         \
      .show   = _show,                          \
      .store  = _store,                         \
};

#define EDAC_PCI_STRING_ATTR(_name,_data,_mode,_show,_store)      \
static struct edac_pci_dev_attribute edac_pci_attr_##_name = {          \
      .attr = {.name = __stringify(_name), .mode = _mode }, \
      .value  = _data,                          \
      .show   = _show,                          \
      .store  = _store,                         \
};

/* PCI Parity control files */
EDAC_PCI_ATTR(check_pci_errors, S_IRUGO | S_IWUSR, edac_pci_int_show,
      edac_pci_int_store);
EDAC_PCI_ATTR(edac_pci_log_pe, S_IRUGO | S_IWUSR, edac_pci_int_show,
      edac_pci_int_store);
EDAC_PCI_ATTR(edac_pci_log_npe, S_IRUGO | S_IWUSR, edac_pci_int_show,
      edac_pci_int_store);
EDAC_PCI_ATTR(edac_pci_panic_on_pe, S_IRUGO | S_IWUSR, edac_pci_int_show,
      edac_pci_int_store);
EDAC_PCI_ATTR(pci_parity_count, S_IRUGO, edac_pci_int_show, NULL);
EDAC_PCI_ATTR(pci_nonparity_count, S_IRUGO, edac_pci_int_show, NULL);

/* Base Attributes of the memory ECC object */
static struct edac_pci_dev_attribute *edac_pci_attr[] = {
      &edac_pci_attr_check_pci_errors,
      &edac_pci_attr_edac_pci_log_pe,
      &edac_pci_attr_edac_pci_log_npe,
      &edac_pci_attr_edac_pci_panic_on_pe,
      &edac_pci_attr_pci_parity_count,
      &edac_pci_attr_pci_nonparity_count,
      NULL,
};

/*
 * edac_pci_release_main_kobj
 *
 *    This release function is called when the reference count to the
 *    passed kobj goes to zero.
 *
 *    This kobj is the 'main' kobject that EDAC PCI instances
 *    link to, and thus provide for proper nesting counts
 */
static void edac_pci_release_main_kobj(struct kobject *kobj)
{

      debugf0("%s() here to module_put(THIS_MODULE)\n", __func__);

      /* last reference to top EDAC PCI kobject has been removed,
       * NOW release our ref count on the core module
       */
      module_put(THIS_MODULE);
}

/* ktype struct for the EDAC PCI main kobj */
static struct kobj_type ktype_edac_pci_main_kobj = {
      .release = edac_pci_release_main_kobj,
      .sysfs_ops = &edac_pci_sysfs_ops,
      .default_attrs = (struct attribute **)edac_pci_attr,
};

/**
 * edac_pci_main_kobj_setup()
 *
 *    setup the sysfs for EDAC PCI attributes
 *    assumes edac_class has already been initialized
 */
int edac_pci_main_kobj_setup(void)
{
      int err;
      struct sysdev_class *edac_class;

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

      /* check and count if we have already created the main kobject */
      if (atomic_inc_return(&edac_pci_sysfs_refcount) != 1)
            return 0;

      /* First time, so create the main kobject and its
       * controls and atributes
       */
      edac_class = edac_get_edac_class();
      if (edac_class == NULL) {
            debugf1("%s() no edac_class\n", __func__);
            err = -ENODEV;
            goto decrement_count_fail;
      }

      /* Need the kobject hook ups, and name setting */
      edac_pci_top_main_kobj.ktype = &ktype_edac_pci_main_kobj;
      edac_pci_top_main_kobj.parent = &edac_class->kset.kobj;

      err = kobject_set_name(&edac_pci_top_main_kobj, "pci");
      if (err)
            goto decrement_count_fail;

      /* Bump the reference count on this module to ensure the
       * modules isn't unloaded until we deconstruct the top
       * level main kobj for EDAC PCI
       */
      if (!try_module_get(THIS_MODULE)) {
            debugf1("%s() try_module_get() failed\n", __func__);
            err = -ENODEV;
            goto decrement_count_fail;
      }

      /* Instanstiate the pci object */
      /* FIXME: maybe new sysdev_create_subdir() */
      err = kobject_register(&edac_pci_top_main_kobj);
      if (err) {
            debugf1("Failed to register '.../edac/pci'\n");
            goto kobject_register_fail;
      }

      /* At this point, to 'release' the top level kobject
       * for EDAC PCI, then edac_pci_main_kobj_teardown()
       * must be used, for resources to be cleaned up properly
       */
      debugf1("Registered '.../edac/pci' kobject\n");

      return 0;

      /* Error unwind statck */
kobject_register_fail:
      module_put(THIS_MODULE);

decrement_count_fail:
      /* if are on this error exit, nothing to tear down */
      atomic_dec(&edac_pci_sysfs_refcount);

      return err;
}

/*
 * edac_pci_main_kobj_teardown()
 *
 *    if no longer linked (needed) remove the top level EDAC PCI
 *    kobject with its controls and attributes
 */
static void edac_pci_main_kobj_teardown(void)
{
      debugf0("%s()\n", __func__);

      /* Decrement the count and only if no more controller instances
       * are connected perform the unregisteration of the top level
       * main kobj
       */
      if (atomic_dec_return(&edac_pci_sysfs_refcount) == 0) {
            debugf0("%s() called kobject_unregister on main kobj\n",
                  __func__);
            kobject_unregister(&edac_pci_top_main_kobj);
      }
}

/*
 *
 * edac_pci_create_sysfs
 *
 *    Create the controls/attributes for the specified EDAC PCI device
 */
int edac_pci_create_sysfs(struct edac_pci_ctl_info *pci)
{
      int err;
      struct kobject *edac_kobj = &pci->kobj;

      debugf0("%s() idx=%d\n", __func__, pci->pci_idx);

      /* create the top main EDAC PCI kobject, IF needed */
      err = edac_pci_main_kobj_setup();
      if (err)
            return err;

      /* Create this instance's kobject under the MAIN kobject */
      err = edac_pci_create_instance_kobj(pci, pci->pci_idx);
      if (err)
            goto unregister_cleanup;

      err = sysfs_create_link(edac_kobj, &pci->dev->kobj, EDAC_PCI_SYMLINK);
      if (err) {
            debugf0("%s() sysfs_create_link() returned err= %d\n",
                  __func__, err);
            goto symlink_fail;
      }

      return 0;

      /* Error unwind stack */
symlink_fail:
      edac_pci_unregister_sysfs_instance_kobj(pci);

unregister_cleanup:
      edac_pci_main_kobj_teardown();

      return err;
}

/*
 * edac_pci_remove_sysfs
 *
 *    remove the controls and attributes for this EDAC PCI device
 */
void edac_pci_remove_sysfs(struct edac_pci_ctl_info *pci)
{
      debugf0("%s() index=%d\n", __func__, pci->pci_idx);

      /* Remove the symlink */
      sysfs_remove_link(&pci->kobj, EDAC_PCI_SYMLINK);

      /* remove this PCI instance's sysfs entries */
      edac_pci_unregister_sysfs_instance_kobj(pci);

      /* Call the main unregister function, which will determine
       * if this 'pci' is the last instance.
       * If it is, the main kobject will be unregistered as a result
       */
      debugf0("%s() calling edac_pci_main_kobj_teardown()\n", __func__);
      edac_pci_main_kobj_teardown();
}

/************************ PCI error handling *************************/
static u16 get_pci_parity_status(struct pci_dev *dev, int secondary)
{
      int where;
      u16 status;

      where = secondary ? PCI_SEC_STATUS : PCI_STATUS;
      pci_read_config_word(dev, where, &status);

      /* If we get back 0xFFFF then we must suspect that the card has been
       * pulled but the Linux PCI layer has not yet finished cleaning up.
       * We don't want to report on such devices
       */

      if (status == 0xFFFF) {
            u32 sanity;

            pci_read_config_dword(dev, 0, &sanity);

            if (sanity == 0xFFFFFFFF)
                  return 0;
      }

      status &= PCI_STATUS_DETECTED_PARITY | PCI_STATUS_SIG_SYSTEM_ERROR |
            PCI_STATUS_PARITY;

      if (status)
            /* reset only the bits we are interested in */
            pci_write_config_word(dev, where, status);

      return status;
}


/* Clear any PCI parity errors logged by this device. */
static void edac_pci_dev_parity_clear(struct pci_dev *dev)
{
      u8 header_type;

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

      get_pci_parity_status(dev, 0);

      /* read the device TYPE, looking for bridges */
      pci_read_config_byte(dev, PCI_HEADER_TYPE, &header_type);

      if ((header_type & 0x7F) == PCI_HEADER_TYPE_BRIDGE)
            get_pci_parity_status(dev, 1);
}

/*
 *  PCI Parity polling
 *
 *    Fucntion to retrieve the current parity status
 *    and decode it
 *
 */
static void edac_pci_dev_parity_test(struct pci_dev *dev)
{
      unsigned long flags;
      u16 status;
      u8 header_type;

      /* stop any interrupts until we can acquire the status */
      local_irq_save(flags);

      /* read the STATUS register on this device */
      status = get_pci_parity_status(dev, 0);

      /* read the device TYPE, looking for bridges */
      pci_read_config_byte(dev, PCI_HEADER_TYPE, &header_type);

      local_irq_restore(flags);

      debugf4("PCI STATUS= 0x%04x %s\n", status, dev->dev.bus_id);

      /* check the status reg for errors */
      if (status) {
            if (status & (PCI_STATUS_SIG_SYSTEM_ERROR)) {
                  edac_printk(KERN_CRIT, EDAC_PCI,
                        "Signaled System Error on %s\n",
                        pci_name(dev));
                  atomic_inc(&pci_nonparity_count);
            }

            if (status & (PCI_STATUS_PARITY)) {
                  edac_printk(KERN_CRIT, EDAC_PCI,
                        "Master Data Parity Error on %s\n",
                        pci_name(dev));

                  atomic_inc(&pci_parity_count);
            }

            if (status & (PCI_STATUS_DETECTED_PARITY)) {
                  edac_printk(KERN_CRIT, EDAC_PCI,
                        "Detected Parity Error on %s\n",
                        pci_name(dev));

                  atomic_inc(&pci_parity_count);
            }
      }


      debugf4("PCI HEADER TYPE= 0x%02x %s\n", header_type, dev->dev.bus_id);

      if ((header_type & 0x7F) == PCI_HEADER_TYPE_BRIDGE) {
            /* On bridges, need to examine secondary status register  */
            status = get_pci_parity_status(dev, 1);

            debugf4("PCI SEC_STATUS= 0x%04x %s\n", status, dev->dev.bus_id);

            /* check the secondary status reg for errors */
            if (status) {
                  if (status & (PCI_STATUS_SIG_SYSTEM_ERROR)) {
                        edac_printk(KERN_CRIT, EDAC_PCI, "Bridge "
                              "Signaled System Error on %s\n",
                              pci_name(dev));
                        atomic_inc(&pci_nonparity_count);
                  }

                  if (status & (PCI_STATUS_PARITY)) {
                        edac_printk(KERN_CRIT, EDAC_PCI, "Bridge "
                              "Master Data Parity Error on "
                              "%s\n", pci_name(dev));

                        atomic_inc(&pci_parity_count);
                  }

                  if (status & (PCI_STATUS_DETECTED_PARITY)) {
                        edac_printk(KERN_CRIT, EDAC_PCI, "Bridge "
                              "Detected Parity Error on %s\n",
                              pci_name(dev));

                        atomic_inc(&pci_parity_count);
                  }
            }
      }
}

/* reduce some complexity in definition of the iterator */
typedef void (*pci_parity_check_fn_t) (struct pci_dev *dev);

/*
 * pci_dev parity list iterator
 *    Scan the PCI device list for one pass, looking for SERRORs
 *    Master Parity ERRORS or Parity ERRORs on primary or secondary devices
 */
static inline void edac_pci_dev_parity_iterator(pci_parity_check_fn_t fn)
{
      struct pci_dev *dev = NULL;

      /* request for kernel access to the next PCI device, if any,
       * and while we are looking at it have its reference count
       * bumped until we are done with it
       */
      while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
            fn(dev);
      }
}

/*
 * edac_pci_do_parity_check
 *
 *    performs the actual PCI parity check operation
 */
void edac_pci_do_parity_check(void)
{
      int before_count;

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

      /* if policy has PCI check off, leave now */
      if (!check_pci_errors)
            return;

      before_count = atomic_read(&pci_parity_count);

      /* scan all PCI devices looking for a Parity Error on devices and
       * bridges.
       * The iterator calls pci_get_device() which might sleep, thus
       * we cannot disable interrupts in this scan.
       */
      edac_pci_dev_parity_iterator(edac_pci_dev_parity_test);

      /* Only if operator has selected panic on PCI Error */
      if (edac_pci_get_panic_on_pe()) {
            /* If the count is different 'after' from 'before' */
            if (before_count != atomic_read(&pci_parity_count))
                  panic("EDAC: PCI Parity Error");
      }
}

/*
 * edac_pci_clear_parity_errors
 *
 *    function to perform an iteration over the PCI devices
 *    and clearn their current status
 */
void edac_pci_clear_parity_errors(void)
{
      /* Clear any PCI bus parity errors that devices initially have logged
       * in their registers.
       */
      edac_pci_dev_parity_iterator(edac_pci_dev_parity_clear);
}

/*
 * edac_pci_handle_pe
 *
 *    Called to handle a PARITY ERROR event
 */
void edac_pci_handle_pe(struct edac_pci_ctl_info *pci, const char *msg)
{

      /* global PE counter incremented by edac_pci_do_parity_check() */
      atomic_inc(&pci->counters.pe_count);

      if (edac_pci_get_log_pe())
            edac_pci_printk(pci, KERN_WARNING,
                        "Parity Error ctl: %s %d: %s\n",
                        pci->ctl_name, pci->pci_idx, msg);

      /*
       * poke all PCI devices and see which one is the troublemaker
       * panic() is called if set
       */
      edac_pci_do_parity_check();
}
EXPORT_SYMBOL_GPL(edac_pci_handle_pe);


/*
 * edac_pci_handle_npe
 *
 *    Called to handle a NON-PARITY ERROR event
 */
void edac_pci_handle_npe(struct edac_pci_ctl_info *pci, const char *msg)
{

      /* global NPE counter incremented by edac_pci_do_parity_check() */
      atomic_inc(&pci->counters.npe_count);

      if (edac_pci_get_log_npe())
            edac_pci_printk(pci, KERN_WARNING,
                        "Non-Parity Error ctl: %s %d: %s\n",
                        pci->ctl_name, pci->pci_idx, msg);

      /*
       * poke all PCI devices and see which one is the troublemaker
       * panic() is called if set
       */
      edac_pci_do_parity_check();
}
EXPORT_SYMBOL_GPL(edac_pci_handle_npe);

/*
 * Define the PCI parameter to the module
 */
module_param(check_pci_errors, int, 0644);
MODULE_PARM_DESC(check_pci_errors,
             "Check for PCI bus parity errors: 0=off 1=on");
module_param(edac_pci_panic_on_pe, int, 0644);
MODULE_PARM_DESC(edac_pci_panic_on_pe,
             "Panic on PCI Bus Parity error: 0=off 1=on");

#endif                        /* CONFIG_PCI */

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