/*
 * edac_mc kernel module
 * (C) 2005-2007 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> www.softwarebitmaker.com
 *
 * (c) 2012-2013 - Mauro Carvalho Chehab
 *      The entire API were re-written, and ported to use struct device
 *
 */

#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/edac.h>
#include <linux/bug.h>
#include <linux/pm_runtime.h>
#include <linux/uaccess.h>

#include "edac_mc.h"
#include "edac_module.h"

/* MC EDAC Controls, setable by module parameter, and sysfs */
static int edac_mc_log_ue = 1;
static int edac_mc_log_ce = 1;
static int edac_mc_panic_on_ue;
static unsigned int edac_mc_poll_msec = 1000;

/* Getter functions for above */
int edac_mc_get_log_ue(void)
{
        return edac_mc_log_ue;
}

int edac_mc_get_log_ce(void)
{
        return edac_mc_log_ce;
}

int edac_mc_get_panic_on_ue(void)
{
        return edac_mc_panic_on_ue;
}

/* this is temporary */
unsigned int edac_mc_get_poll_msec(void)
{
        return edac_mc_poll_msec;
}

static int edac_set_poll_msec(const char *val, const struct kernel_param *kp)
{
        unsigned int i;
        int ret;

        if (!val)
                return -EINVAL;

        ret = kstrtouint(val, 0, &i);
        if (ret)
                return ret;

        if (i < 1000)
                return -EINVAL;

        *((unsigned int *)kp->arg) = i;

        /* notify edac_mc engine to reset the poll period */
        edac_mc_reset_delay_period(i);

        return 0;
}

/* Parameter declarations for above */
module_param(edac_mc_panic_on_ue, int, 0644);
MODULE_PARM_DESC(edac_mc_panic_on_ue, "Panic on uncorrected error: 0=off 1=on");
module_param(edac_mc_log_ue, int, 0644);
MODULE_PARM_DESC(edac_mc_log_ue,
                 "Log uncorrectable error to console: 0=off 1=on");
module_param(edac_mc_log_ce, int, 0644);
MODULE_PARM_DESC(edac_mc_log_ce,
                 "Log correctable error to console: 0=off 1=on");
module_param_call(edac_mc_poll_msec, edac_set_poll_msec, param_get_uint,
                  &edac_mc_poll_msec, 0644);
MODULE_PARM_DESC(edac_mc_poll_msec, "Polling period in milliseconds");

static struct device *mci_pdev;

/*
 * various constants for Memory Controllers
 */
static const char * const dev_types[] = {
        [DEV_UNKNOWN] = "Unknown",
        [DEV_X1] = "x1",
        [DEV_X2] = "x2",
        [DEV_X4] = "x4",
        [DEV_X8] = "x8",
        [DEV_X16] = "x16",
        [DEV_X32] = "x32",
        [DEV_X64] = "x64"
};

static const char * const edac_caps[] = {
        [EDAC_UNKNOWN] = "Unknown",
        [EDAC_NONE] = "None",
        [EDAC_RESERVED] = "Reserved",
        [EDAC_PARITY] = "PARITY",
        [EDAC_EC] = "EC",
        [EDAC_SECDED] = "SECDED",
        [EDAC_S2ECD2ED] = "S2ECD2ED",
        [EDAC_S4ECD4ED] = "S4ECD4ED",
        [EDAC_S8ECD8ED] = "S8ECD8ED",
        [EDAC_S16ECD16ED] = "S16ECD16ED"
};

/*
 * Per-dimm (or per-rank) devices
 */

#define to_dimm(k) container_of(k, struct dimm_info, dev)

/* show/store functions for DIMM Label attributes */
static ssize_t dimmdev_location_show(struct device *dev,
                                     struct device_attribute *mattr, char *data)
{
        struct dimm_info *dimm = to_dimm(dev);
        ssize_t count;

        count = edac_dimm_info_location(dimm, data, PAGE_SIZE);
        count += scnprintf(data + count, PAGE_SIZE - count, "\n");

        return count;
}

static ssize_t dimmdev_label_show(struct device *dev,
                                  struct device_attribute *mattr, char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        /* if field has not been initialized, there is nothing to send */
        if (!dimm->label[0])
                return 0;

        return sysfs_emit(data, "%s\n", dimm->label);
}

static ssize_t dimmdev_label_store(struct device *dev,
                                   struct device_attribute *mattr,
                                   const char *data,
                                   size_t count)
{
        struct dimm_info *dimm = to_dimm(dev);
        size_t copy_count = count;

        if (count == 0)
                return -EINVAL;

        if (data[count - 1] == '\0' || data[count - 1] == '\n')
                copy_count -= 1;

        if (copy_count == 0 || copy_count >= sizeof(dimm->label))
                return -EINVAL;

        memcpy(dimm->label, data, copy_count);
        dimm->label[copy_count] = '\0';

        return count;
}

static ssize_t dimmdev_size_show(struct device *dev,
                                 struct device_attribute *mattr, char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%u\n", PAGES_TO_MiB(dimm->nr_pages));
}

static ssize_t dimmdev_mem_type_show(struct device *dev,
                                     struct device_attribute *mattr, char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%s\n", edac_mem_types[dimm->mtype]);
}

static ssize_t dimmdev_dev_type_show(struct device *dev,
                                     struct device_attribute *mattr, char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%s\n", dev_types[dimm->dtype]);
}

static ssize_t dimmdev_edac_mode_show(struct device *dev,
                                      struct device_attribute *mattr,
                                      char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%s\n", edac_caps[dimm->edac_mode]);
}

static ssize_t dimmdev_ce_count_show(struct device *dev,
                                      struct device_attribute *mattr,
                                      char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%u\n", dimm->ce_count);
}

static ssize_t dimmdev_ue_count_show(struct device *dev,
                                      struct device_attribute *mattr,
                                      char *data)
{
        struct dimm_info *dimm = to_dimm(dev);

        return sysfs_emit(data, "%u\n", dimm->ue_count);
}

/* dimm/rank attribute files */
static DEVICE_ATTR(dimm_label, S_IRUGO | S_IWUSR,
                   dimmdev_label_show, dimmdev_label_store);
static DEVICE_ATTR(dimm_location, S_IRUGO, dimmdev_location_show, NULL);
static DEVICE_ATTR(size, S_IRUGO, dimmdev_size_show, NULL);
static DEVICE_ATTR(dimm_mem_type, S_IRUGO, dimmdev_mem_type_show, NULL);
static DEVICE_ATTR(dimm_dev_type, S_IRUGO, dimmdev_dev_type_show, NULL);
static DEVICE_ATTR(dimm_edac_mode, S_IRUGO, dimmdev_edac_mode_show, NULL);
static DEVICE_ATTR(dimm_ce_count, S_IRUGO, dimmdev_ce_count_show, NULL);
static DEVICE_ATTR(dimm_ue_count, S_IRUGO, dimmdev_ue_count_show, NULL);

/* attributes of the dimm<id>/rank<id> object */
static struct attribute *dimm_attrs[] = {
        &dev_attr_dimm_label.attr,
        &dev_attr_dimm_location.attr,
        &dev_attr_size.attr,
        &dev_attr_dimm_mem_type.attr,
        &dev_attr_dimm_dev_type.attr,
        &dev_attr_dimm_edac_mode.attr,
        &dev_attr_dimm_ce_count.attr,
        &dev_attr_dimm_ue_count.attr,
        NULL,
};

static const struct attribute_group dimm_attr_grp = {
        .attrs  = dimm_attrs,
};

static const struct attribute_group *dimm_attr_groups[] = {
        &dimm_attr_grp,
        NULL
};

static const struct device_type dimm_attr_type = {
        .groups         = dimm_attr_groups,
};

static void dimm_release(struct device *dev)
{
        /*
         * Nothing to do, just unregister sysfs here. The mci
         * device owns the data and will also release it.
         */
}

/* Create a DIMM object under specified memory controller device */
static int edac_create_dimm_object(struct mem_ctl_info *mci,
                                   struct dimm_info *dimm)
{
        int err;
        dimm->mci = mci;

        dimm->dev.type = &dimm_attr_type;
        dimm->dev.release = dimm_release;
        device_initialize(&dimm->dev);

        dimm->dev.parent = &mci->dev;
        if (mci->csbased)
                dev_set_name(&dimm->dev, "rank%d", dimm->idx);
        else
                dev_set_name(&dimm->dev, "dimm%d", dimm->idx);
        dev_set_drvdata(&dimm->dev, dimm);
        pm_runtime_forbid(&mci->dev);

        err = device_add(&dimm->dev);
        if (err) {
                edac_dbg(1, "failure: create device %s\n", dev_name(&dimm->dev));
                put_device(&dimm->dev);
                return err;
        }

        if (IS_ENABLED(CONFIG_EDAC_DEBUG)) {
                char location[80];

                edac_dimm_info_location(dimm, location, sizeof(location));
                edac_dbg(0, "device %s created at location %s\n",
                        dev_name(&dimm->dev), location);
        }

        return 0;
}

/*
 * Memory controller device
 */

#define to_mci(k) container_of(k, struct mem_ctl_info, dev)

static ssize_t mci_reset_counters_store(struct device *dev,
                                        struct device_attribute *mattr,
                                        const char *data, size_t count)
{
        struct mem_ctl_info *mci = to_mci(dev);
        struct dimm_info *dimm;
        int row, chan;

        mci->ue_mc = 0;
        mci->ce_mc = 0;
        mci->ue_noinfo_count = 0;
        mci->ce_noinfo_count = 0;

        for (row = 0; row < mci->nr_csrows; row++) {
                struct csrow_info *ri = mci->csrows[row];

                ri->ue_count = 0;
                ri->ce_count = 0;

                for (chan = 0; chan < ri->nr_channels; chan++)
                        ri->channels[chan]->ce_count = 0;
        }

        mci_for_each_dimm(mci, dimm) {
                dimm->ue_count = 0;
                dimm->ce_count = 0;
        }

        mci->start_time = jiffies;
        return count;
}

/* Memory scrubbing interface:
 *
 * A MC driver can limit the scrubbing bandwidth based on the CPU type.
 * Therefore, ->set_sdram_scrub_rate should be made to return the actual
 * bandwidth that is accepted or 0 when scrubbing is to be disabled.
 *
 * Negative value still means that an error has occurred while setting
 * the scrub rate.
 */
static ssize_t mci_sdram_scrub_rate_store(struct device *dev,
                                          struct device_attribute *mattr,
                                          const char *data, size_t count)
{
        struct mem_ctl_info *mci = to_mci(dev);
        unsigned long bandwidth = 0;
        int new_bw = 0;

        if (kstrtoul(data, 10, &bandwidth) < 0)
                return -EINVAL;

        new_bw = mci->set_sdram_scrub_rate(mci, bandwidth);
        if (new_bw < 0) {
                edac_printk(KERN_WARNING, EDAC_MC,
                            "Error setting scrub rate to: %lu\n", bandwidth);
                return -EINVAL;
        }

        return count;
}

/*
 * ->get_sdram_scrub_rate() return value semantics same as above.
 */
static ssize_t mci_sdram_scrub_rate_show(struct device *dev,
                                         struct device_attribute *mattr,
                                         char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);
        int bandwidth = 0;

        bandwidth = mci->get_sdram_scrub_rate(mci);
        if (bandwidth < 0) {
                edac_printk(KERN_DEBUG, EDAC_MC, "Error reading scrub rate\n");
                return bandwidth;
        }

        return sysfs_emit(data, "%d\n", bandwidth);
}

/* default attribute files for the MCI object */
static ssize_t mci_ue_count_show(struct device *dev,
                                 struct device_attribute *mattr,
                                 char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%u\n", mci->ue_mc);
}

static ssize_t mci_ce_count_show(struct device *dev,
                                 struct device_attribute *mattr,
                                 char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%u\n", mci->ce_mc);
}

static ssize_t mci_ce_noinfo_show(struct device *dev,
                                  struct device_attribute *mattr,
                                  char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%u\n", mci->ce_noinfo_count);
}

static ssize_t mci_ue_noinfo_show(struct device *dev,
                                  struct device_attribute *mattr,
                                  char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%u\n", mci->ue_noinfo_count);
}

static ssize_t mci_seconds_show(struct device *dev,
                                struct device_attribute *mattr,
                                char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%ld\n", (jiffies - mci->start_time) / HZ);
}

static ssize_t mci_ctl_name_show(struct device *dev,
                                 struct device_attribute *mattr,
                                 char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);

        return sysfs_emit(data, "%s\n", mci->ctl_name);
}

static ssize_t mci_size_mb_show(struct device *dev,
                                struct device_attribute *mattr,
                                char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);
        int total_pages = 0, csrow_idx, j;

        for (csrow_idx = 0; csrow_idx < mci->nr_csrows; csrow_idx++) {
                struct csrow_info *csrow = mci->csrows[csrow_idx];

                for (j = 0; j < csrow->nr_channels; j++) {
                        struct dimm_info *dimm = csrow->channels[j]->dimm;

                        total_pages += dimm->nr_pages;
                }
        }

        return sysfs_emit(data, "%u\n", PAGES_TO_MiB(total_pages));
}

static ssize_t mci_max_location_show(struct device *dev,
                                     struct device_attribute *mattr,
                                     char *data)
{
        struct mem_ctl_info *mci = to_mci(dev);
        int len = PAGE_SIZE;
        char *p = data;
        int i, n;

        for (i = 0; i < mci->n_layers; i++) {
                n = scnprintf(p, len, "%s %d ",
                              edac_layer_name[mci->layers[i].type],
                              mci->layers[i].size - 1);
                len -= n;
                if (len <= 0)
                        goto out;

                p += n;
        }

        p += scnprintf(p, len, "\n");
out:
        return p - data;
}

/* default Control file */
static DEVICE_ATTR(reset_counters, S_IWUSR, NULL, mci_reset_counters_store);

/* default Attribute files */
static DEVICE_ATTR(mc_name, S_IRUGO, mci_ctl_name_show, NULL);
static DEVICE_ATTR(size_mb, S_IRUGO, mci_size_mb_show, NULL);
static DEVICE_ATTR(seconds_since_reset, S_IRUGO, mci_seconds_show, NULL);
static DEVICE_ATTR(ue_noinfo_count, S_IRUGO, mci_ue_noinfo_show, NULL);
static DEVICE_ATTR(ce_noinfo_count, S_IRUGO, mci_ce_noinfo_show, NULL);
static DEVICE_ATTR(ue_count, S_IRUGO, mci_ue_count_show, NULL);
static DEVICE_ATTR(ce_count, S_IRUGO, mci_ce_count_show, NULL);
static DEVICE_ATTR(max_location, S_IRUGO, mci_max_location_show, NULL);

/* memory scrubber attribute file */
static DEVICE_ATTR(sdram_scrub_rate, 0, mci_sdram_scrub_rate_show,
            mci_sdram_scrub_rate_store); /* umode set later in is_visible */

static struct attribute *mci_attrs[] = {
        &dev_attr_reset_counters.attr,
        &dev_attr_mc_name.attr,
        &dev_attr_size_mb.attr,
        &dev_attr_seconds_since_reset.attr,
        &dev_attr_ue_noinfo_count.attr,
        &dev_attr_ce_noinfo_count.attr,
        &dev_attr_ue_count.attr,
        &dev_attr_ce_count.attr,
        &dev_attr_max_location.attr,
        &dev_attr_sdram_scrub_rate.attr,
        NULL
};

static umode_t mci_attr_is_visible(struct kobject *kobj,
                                   struct attribute *attr, int idx)
{
        struct device *dev = kobj_to_dev(kobj);
        struct mem_ctl_info *mci = to_mci(dev);
        umode_t mode = 0;

        if (attr != &dev_attr_sdram_scrub_rate.attr)
                return attr->mode;
        if (mci->get_sdram_scrub_rate)
                mode |= S_IRUGO;
        if (mci->set_sdram_scrub_rate)
                mode |= S_IWUSR;
        return mode;
}

static const struct attribute_group mci_attr_grp = {
        .attrs  = mci_attrs,
        .is_visible = mci_attr_is_visible,
};

static const struct attribute_group *mci_attr_groups[] = {
        &mci_attr_grp,
        NULL
};

static const struct device_type mci_attr_type = {
        .groups         = mci_attr_groups,
};

/*
 * Create a new Memory Controller kobject instance,
 *      mc<id> under the 'mc' directory
 *
 * Return:
 *      0       Success
 *      !0      Failure
 */
int edac_create_sysfs_mci_device(struct mem_ctl_info *mci,
                                 const struct attribute_group **groups)
{
        struct dimm_info *dimm;
        int err;

        /* get the /sys/devices/system/edac subsys reference */
        mci->dev.type = &mci_attr_type;
        mci->dev.parent = mci_pdev;
        mci->dev.groups = groups;
        dev_set_name(&mci->dev, "mc%d", mci->mc_idx);
        dev_set_drvdata(&mci->dev, mci);
        pm_runtime_forbid(&mci->dev);

        err = device_add(&mci->dev);
        if (err < 0) {
                edac_dbg(1, "failure: create device %s\n", dev_name(&mci->dev));
                /* no put_device() here, free mci with _edac_mc_free() */
                return err;
        }

        edac_dbg(0, "device %s created\n", dev_name(&mci->dev));

        /*
         * Create the dimm/rank devices
         */
        mci_for_each_dimm(mci, dimm) {
                /* Only expose populated DIMMs */
                if (!dimm->nr_pages)
                        continue;

                err = edac_create_dimm_object(mci, dimm);
                if (err)
                        goto fail;
        }

        edac_create_debugfs_nodes(mci);
        return 0;

fail:
        edac_remove_sysfs_mci_device(mci);

        return err;
}

/*
 * remove a Memory Controller instance
 */
void edac_remove_sysfs_mci_device(struct mem_ctl_info *mci)
{
        struct dimm_info *dimm;

        if (!device_is_registered(&mci->dev))
                return;

        edac_dbg(0, "\n");

#ifdef CONFIG_EDAC_DEBUG
        edac_debugfs_remove_recursive(mci->debugfs);
#endif

        mci_for_each_dimm(mci, dimm) {
                if (!device_is_registered(&dimm->dev))
                        continue;
                edac_dbg(1, "unregistering device %s\n", dev_name(&dimm->dev));
                device_unregister(&dimm->dev);
        }

        /* only remove the device, but keep mci */
        device_del(&mci->dev);
}

static void mc_attr_release(struct device *dev)
{
        /*
         * There's no container structure here, as this is just the mci
         * parent device, used to create the /sys/devices/mc sysfs node.
         * So, there are no attributes on it.
         */
        edac_dbg(1, "device %s released\n", dev_name(dev));
        kfree(dev);
}

/*
 * Init/exit code for the module. Basically, creates/removes /sys/class/rc
 */
int __init edac_mc_sysfs_init(void)
{
        int err;

        mci_pdev = kzalloc_obj(*mci_pdev);
        if (!mci_pdev)
                return -ENOMEM;

        mci_pdev->bus = edac_get_sysfs_subsys();
        mci_pdev->release = mc_attr_release;
        mci_pdev->init_name = "mc";

        err = device_register(mci_pdev);
        if (err < 0) {
                edac_dbg(1, "failure: create device %s\n", dev_name(mci_pdev));
                put_device(mci_pdev);
                return err;
        }

        edac_dbg(0, "device %s created\n", dev_name(mci_pdev));

        return 0;
}

void edac_mc_sysfs_exit(void)
{
        device_unregister(mci_pdev);
}