edac_pci_sysfs.c

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/*
 * (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 <[email protected]>
 *
 */
#include <linux/module.h>
#include <linux/edac.h>
#include <linux/slab.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;
}

static int edac_pci_get_log_pe(void)
{
    return edac_pci_log_pe;
}

static int edac_pci_get_log_npe(void)
{
    return edac_pci_log_npe;
}

static 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;

    edac_dbg(0, "\n");

    /* 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 const 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;

    edac_dbg(0, "\n");

    /* 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_init_and_add(&pci->kobj, &ktype_pci_instance,
                   edac_pci_top_main_kobj, "pci%d", idx);
    if (err != 0) {
        edac_dbg(2, "failed to register instance pci%d\n", idx);
        kobject_put(edac_pci_top_main_kobj);
        goto error_out;
    }

    kobject_uevent(&pci->kobj, KOBJ_ADD);
    edac_dbg(1, "Register instance 'pci%d' kobject\n", idx);

    return 0;

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

/*
 * edac_pci_unregister_sysfs_instance_kobj
 *
 *  unregister the kobj for the EDAC PCI instance
 */
static void edac_pci_unregister_sysfs_instance_kobj(
            struct edac_pci_ctl_info *pci)
{
    edac_dbg(0, "\n");

    /* Unregister the instance kobject and allow its release
     * function release the main reference count and then
     * kfree the memory
     */
    kobject_put(&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 const 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)
{
    edac_dbg(0, "here to module_put(THIS_MODULE)\n");

    kfree(kobj);

    /* 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,
};

static int edac_pci_main_kobj_setup(void)
{
    int err;
    struct bus_type *edac_subsys;

    edac_dbg(0, "\n");

    /* 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 attributes
     */
    edac_subsys = edac_get_sysfs_subsys();
    if (edac_subsys == NULL) {
        edac_dbg(1, "no edac_subsys\n");
        err = -ENODEV;
        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)) {
        edac_dbg(1, "try_module_get() failed\n");
        err = -ENODEV;
        goto mod_get_fail;
    }

    edac_pci_top_main_kobj = kzalloc(sizeof(struct kobject), GFP_KERNEL);
    if (!edac_pci_top_main_kobj) {
        edac_dbg(1, "Failed to allocate\n");
        err = -ENOMEM;
        goto kzalloc_fail;
    }

    /* Instanstiate the pci object */
    err = kobject_init_and_add(edac_pci_top_main_kobj,
                   &ktype_edac_pci_main_kobj,
                   &edac_subsys->dev_root->kobj, "pci");
    if (err) {
        edac_dbg(1, "Failed to register '.../edac/pci'\n");
        goto kobject_init_and_add_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
     */
    kobject_uevent(edac_pci_top_main_kobj, KOBJ_ADD);
    edac_dbg(1, "Registered '.../edac/pci' kobject\n");

    return 0;

    /* Error unwind statck */
kobject_init_and_add_fail:
    kfree(edac_pci_top_main_kobj);

kzalloc_fail:
    module_put(THIS_MODULE);

mod_get_fail:
    edac_put_sysfs_subsys();

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)
{
    edac_dbg(0, "\n");

    /* 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) {
        edac_dbg(0, "called kobject_put on main kobj\n");
        kobject_put(edac_pci_top_main_kobj);
    }
    edac_put_sysfs_subsys();
}

/*
 *
 * 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;

    edac_dbg(0, "idx=%d\n", 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) {
        edac_dbg(0, "sysfs_create_link() returned err= %d\n", 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)
{
    edac_dbg(0, "index=%d\n", 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
     */
    edac_dbg(0, "calling edac_pci_main_kobj_teardown()\n");
    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;

    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
 *
 *  Function 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);

    edac_dbg(4, "PCI STATUS= 0x%04x %s\n", status, dev_name(&dev->dev));

    /* check the status reg for errors on boards NOT marked as broken
     * if broken, we cannot trust any of the status bits
     */
    if (status && !dev->broken_parity_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);
        }
    }


    edac_dbg(4, "PCI HEADER TYPE= 0x%02x %s\n",
         header_type, dev_name(&dev->dev));

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

        edac_dbg(4, "PCI SEC_STATUS= 0x%04x %s\n",
             status, dev_name(&dev->dev));

        /* check the secondary status reg for errors,
         * on NOT broken boards
         */
        if (status && !dev->broken_parity_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;

    edac_dbg(3, "\n");

    /* 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 */