/*
 * (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/edac.h>
#include <linux/slab.h>
#include <linux/ctype.h>

#include "edac_pci.h"
#include "edac_module.h"

#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->store)
                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,
};

/**
 * edac_pci_main_kobj_setup: Setup the sysfs for EDAC PCI attributes.
 */
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();

        /* 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 decrement_count_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:
        kobject_put(edac_pci_top_main_kobj);

kzalloc_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)
{
        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);
        }
}

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;
}

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 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;

        for_each_pci_dev(dev)
                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");