edac_pci.c

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/*
 * EDAC PCI component
 *
 * Author: Dave Jiang <[email protected]>
 *
 * 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/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 LIST_HEAD(edac_pci_list);
static atomic_t pci_indexes = ATOMIC_INIT(0);

/*
 * 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 *p = NULL, *pvt;
    unsigned int size;

    edac_dbg(1, "\n");

    pci = edac_align_ptr(&p, sizeof(*pci), 1);
    pvt = edac_align_ptr(&p, 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 information, 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)
{
    edac_dbg(1, "\n");

    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;

    edac_dbg(1, "\n");

    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;

    edac_dbg(1, "\n");

    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",
        dev_name(rover->dev), edac_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;
}

/*
 * 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);

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

#if 0
/* Older code, but might use in the future */

/*
 * 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);
#endif

/*
 * 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 = to_delayed_work(work_req);
    struct edac_pci_ctl_info *pci = to_edac_pci_ctl_work(d_work);
    int msec;
    unsigned long delay;

    edac_dbg(3, "checking\n");

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

    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;

    edac_dbg(0, "\n");

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

    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_alloc_index: Allocate a unique PCI index number
 *
 * Return:
 *      allocated index number
 *
 */
int edac_pci_alloc_index(void)
{
    return atomic_inc_return(&pci_indexes) - 1;
}
EXPORT_SYMBOL_GPL(edac_pci_alloc_index);

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

    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,
            edac_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;

    edac_dbg(0, "\n");

    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, edac_dev_name(pci));

    return pci;
}
EXPORT_SYMBOL_GPL(edac_pci_del_device);

/*
 * edac_pci_generic_check
 *
 *  a Generic parity check API
 */
static void edac_pci_generic_check(struct edac_pci_ctl_info *pci)
{
    edac_dbg(4, "\n");
    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) {
        edac_dbg(3, "failed edac_pci_add_device()\n");
        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)
{
    edac_dbg(0, "pci mod=%s\n", pci->mod_name);

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