linux/drivers/edac/edac_mc_sysfs.c

/*
 * 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 - Mauro Carvalho Chehab <mchehab@redhat.com>
 *	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 "edac_core.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 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 */
int edac_mc_get_poll_msec(void)
{
	return edac_mc_poll_msec;
}

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

	if (!val)
		return -EINVAL;

	ret = strict_strtol(val, 0, &l);
	if (ret == -EINVAL || ((int)l != l))
		return -EINVAL;
	*((int *)kp->arg) = l;

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

	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_int,
		  &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 *mem_types[] = {
	[MEM_EMPTY] = "Empty",
	[MEM_RESERVED] = "Reserved",
	[MEM_UNKNOWN] = "Unknown",
	[MEM_FPM] = "FPM",
	[MEM_EDO] = "EDO",
	[MEM_BEDO] = "BEDO",
	[MEM_SDR] = "Unbuffered-SDR",
	[MEM_RDR] = "Registered-SDR",
	[MEM_DDR] = "Unbuffered-DDR",
	[MEM_RDDR] = "Registered-DDR",
	[MEM_RMBS] = "RMBS",
	[MEM_DDR2] = "Unbuffered-DDR2",
	[MEM_FB_DDR2] = "FullyBuffered-DDR2",
	[MEM_RDDR2] = "Registered-DDR2",
	[MEM_XDR] = "XDR",
	[MEM_DDR3] = "Unbuffered-DDR3",
	[MEM_RDDR3] = "Registered-DDR3"
};

static const char *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 *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"
};

/*
 * EDAC sysfs CSROW data structures and methods
 */

#define to_csrow(k) container_of(k, struct csrow_info, dev)

/*
 * We need it to avoid namespace conflicts between the legacy API
 * and the per-dimm/per-rank one
 */
#define DEVICE_ATTR_LEGACY(_name, _mode, _show, _store) \
	struct device_attribute dev_attr_legacy_##_name = __ATTR(_name, _mode, _show, _store)

struct dev_ch_attribute {
	struct device_attribute attr;
	int channel;
};

#define DEVICE_CHANNEL(_name, _mode, _show, _store, _var) \
	struct dev_ch_attribute dev_attr_legacy_##_name = \
		{ __ATTR(_name, _mode, _show, _store), (_var) }

#define to_channel(k) (container_of(k, struct dev_ch_attribute, attr)->channel)

/* Set of more default csrow<id> attribute show/store functions */
static ssize_t csrow_ue_count_show(struct device *dev,
				   struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);

	return sprintf(data, "%u\n", csrow->ue_count);
}

static ssize_t csrow_ce_count_show(struct device *dev,
				   struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);

	return sprintf(data, "%u\n", csrow->ce_count);
}

static ssize_t csrow_size_show(struct device *dev,
			       struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);
	int i;
	u32 nr_pages = 0;

	for (i = 0; i < csrow->nr_channels; i++)
		nr_pages += csrow->channels[i].dimm->nr_pages;
	return sprintf(data, "%u\n", PAGES_TO_MiB(nr_pages));
}

static ssize_t csrow_mem_type_show(struct device *dev,
				   struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);

	return sprintf(data, "%s\n", mem_types[csrow->channels[0].dimm->mtype]);
}

static ssize_t csrow_dev_type_show(struct device *dev,
				   struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);

	return sprintf(data, "%s\n", dev_types[csrow->channels[0].dimm->dtype]);
}

static ssize_t csrow_edac_mode_show(struct device *dev,
				    struct device_attribute *mattr,
				    char *data)
{
	struct csrow_info *csrow = to_csrow(dev);

	return sprintf(data, "%s\n", edac_caps[csrow->channels[0].dimm->edac_mode]);
}

/* show/store functions for DIMM Label attributes */
static ssize_t channel_dimm_label_show(struct device *dev,
				       struct device_attribute *mattr,
				       char *data)
{
	struct csrow_info *csrow = to_csrow(dev);
	unsigned chan = to_channel(mattr);
	struct rank_info *rank = &csrow->channels[chan];

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

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

static ssize_t channel_dimm_label_store(struct device *dev,
					struct device_attribute *mattr,
					const char *data, size_t count)
{
	struct csrow_info *csrow = to_csrow(dev);
	unsigned chan = to_channel(mattr);
	struct rank_info *rank = &csrow->channels[chan];

	ssize_t max_size = 0;

	max_size = min((ssize_t) count, (ssize_t) EDAC_MC_LABEL_LEN - 1);
	strncpy(rank->dimm->label, data, max_size);
	rank->dimm->label[max_size] = '\0';

	return max_size;
}

/* show function for dynamic chX_ce_count attribute */
static ssize_t channel_ce_count_show(struct device *dev,
				     struct device_attribute *mattr, char *data)
{
	struct csrow_info *csrow = to_csrow(dev);
	unsigned chan = to_channel(mattr);
	struct rank_info *rank = &csrow->channels[chan];

	return sprintf(data, "%u\n", rank->ce_count);
}

/* cwrow<id>/attribute files */
DEVICE_ATTR_LEGACY(size_mb, S_IRUGO, csrow_size_show, NULL);
DEVICE_ATTR_LEGACY(dev_type, S_IRUGO, csrow_dev_type_show, NULL);
DEVICE_ATTR_LEGACY(mem_type, S_IRUGO, csrow_mem_type_show, NULL);
DEVICE_ATTR_LEGACY(edac_mode, S_IRUGO, csrow_edac_mode_show, NULL);
DEVICE_ATTR_LEGACY(ue_count, S_IRUGO, csrow_ue_count_show, NULL);
DEVICE_ATTR_LEGACY(ce_count, S_IRUGO, csrow_ce_count_show, NULL);

/* default attributes of the CSROW<id> object */
static struct attribute *csrow_attrs[] = {
	&dev_attr_legacy_dev_type.attr,
	&dev_attr_legacy_mem_type.attr,
	&dev_attr_legacy_edac_mode.attr,
	&dev_attr_legacy_size_mb.attr,
	&dev_attr_legacy_ue_count.attr,
	&dev_attr_legacy_ce_count.attr,
	NULL,
};

static struct attribute_group csrow_attr_grp = {
	.attrs	= csrow_attrs,
};

static const struct attribute_group *csrow_attr_groups[] = {
	&csrow_attr_grp,
	NULL
};

static void csrow_attr_release(struct device *device)
{
	debugf1("Releasing csrow device %s\n", dev_name(device));
}

static struct device_type csrow_attr_type = {
	.groups		= csrow_attr_groups,
	.release	= csrow_attr_release,
};

/*
 * possible dynamic channel DIMM Label attribute files
 *
 */

#define EDAC_NR_CHANNELS	6

DEVICE_CHANNEL(ch0_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 0);
DEVICE_CHANNEL(ch1_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 1);
DEVICE_CHANNEL(ch2_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 2);
DEVICE_CHANNEL(ch3_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 3);
DEVICE_CHANNEL(ch4_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 4);
DEVICE_CHANNEL(ch5_dimm_label, S_IRUGO | S_IWUSR,
	channel_dimm_label_show, channel_dimm_label_store, 5);

/* Total possible dynamic DIMM Label attribute file table */
static struct device_attribute *dynamic_csrow_dimm_attr[] = {
	&dev_attr_legacy_ch0_dimm_label.attr,
	&dev_attr_legacy_ch1_dimm_label.attr,
	&dev_attr_legacy_ch2_dimm_label.attr,
	&dev_attr_legacy_ch3_dimm_label.attr,
	&dev_attr_legacy_ch4_dimm_label.attr,
	&dev_attr_legacy_ch5_dimm_label.attr
};

/* possible dynamic channel ce_count attribute files */
DEVICE_CHANNEL(ch0_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 0);
DEVICE_CHANNEL(ch1_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 1);
DEVICE_CHANNEL(ch2_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 2);
DEVICE_CHANNEL(ch3_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 3);
DEVICE_CHANNEL(ch4_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 4);
DEVICE_CHANNEL(ch5_ce_count, S_IRUGO | S_IWUSR,
		   channel_ce_count_show, NULL, 5);

/* Total possible dynamic ce_count attribute file table */
static struct device_attribute *dynamic_csrow_ce_count_attr[] = {
	&dev_attr_legacy_ch0_ce_count.attr,
	&dev_attr_legacy_ch1_ce_count.attr,
	&dev_attr_legacy_ch2_ce_count.attr,
	&dev_attr_legacy_ch3_ce_count.attr,
	&dev_attr_legacy_ch4_ce_count.attr,
	&dev_attr_legacy_ch5_ce_count.attr
};

/* Create a CSROW object under specifed edac_mc_device */
static int edac_create_csrow_object(struct mem_ctl_info *mci,
				    struct csrow_info *csrow, int index)
{
	int err, chan;

	if (csrow->nr_channels >= EDAC_NR_CHANNELS)
		return -ENODEV;

	csrow->dev.type = &csrow_attr_type;
	csrow->dev.bus = &mci->bus;
	device_initialize(&csrow->dev);
	csrow->dev.parent = &mci->dev;
	dev_set_name(&csrow->dev, "csrow%d", index);
	dev_set_drvdata(&csrow->dev, csrow);

	debugf0("%s(): creating (virtual) csrow node %s\n", __func__,
		dev_name(&csrow->dev));

	err = device_add(&csrow->dev);
	if (err < 0)
		return err;

	for (chan = 0; chan < csrow->nr_channels; chan++) {
		err = device_create_file(&csrow->dev,
					 dynamic_csrow_dimm_attr[chan]);
		if (err < 0)
			goto error;
		err = device_create_file(&csrow->dev,
					 dynamic_csrow_ce_count_attr[chan]);
		if (err < 0) {
			device_remove_file(&csrow->dev,
					   dynamic_csrow_dimm_attr[chan]);
			goto error;
		}
	}

	return 0;

error:
	for (--chan; chan >= 0; chan--) {
		device_remove_file(&csrow->dev,
					dynamic_csrow_dimm_attr[chan]);
		device_remove_file(&csrow->dev,
					   dynamic_csrow_ce_count_attr[chan]);
	}
	put_device(&csrow->dev);

	return err;
}

/* Create a CSROW object under specifed edac_mc_device */
static int edac_create_csrow_objects(struct mem_ctl_info *mci)
{
	int err, i, chan;
	struct csrow_info *csrow;

	for (i = 0; i < mci->nr_csrows; i++) {
		err = edac_create_csrow_object(mci, &mci->csrows[i], i);
		if (err < 0)
			goto error;
	}
	return 0;

error:
	for (--i; i >= 0; i--) {
		csrow = &mci->csrows[i];
		for (chan = csrow->nr_channels - 1; chan >= 0; chan--) {
			device_remove_file(&csrow->dev,
						dynamic_csrow_dimm_attr[chan]);
			device_remove_file(&csrow->dev,
						dynamic_csrow_ce_count_attr[chan]);
		}
		put_device(&mci->csrows[i].dev);
	}

	return err;
}

static void edac_delete_csrow_objects(struct mem_ctl_info *mci)
{
	int i, chan;
	struct csrow_info *csrow;

	for (i = mci->nr_csrows - 1; i >= 0; i--) {
		csrow = &mci->csrows[i];
		for (chan = csrow->nr_channels - 1; chan >= 0; chan--) {
			debugf1("Removing csrow %d channel %d sysfs nodes\n",
				i, chan);
			device_remove_file(&csrow->dev,
						dynamic_csrow_dimm_attr[chan]);
			device_remove_file(&csrow->dev,
						dynamic_csrow_ce_count_attr[chan]);
		}
		put_device(&mci->csrows[i].dev);
		device_del(&mci->csrows[i].dev);
	}
}

/*
 * 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);
	int cnt, row, chan, i;
	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;
	}

	cnt = 1;
	for (i = 0; i < mci->n_layers; i++) {
		cnt *= mci->layers[i].size;
		memset(mci->ce_per_layer[i], 0, cnt * sizeof(u32));
		memset(mci->ue_per_layer[i], 0, cnt * sizeof(u32));
	}

	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 (!mci->set_sdram_scrub_rate)
		return -ENODEV;

	if (strict_strtoul(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;

	if (!mci->get_sdram_scrub_rate)
		return -ENODEV;

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

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

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

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

/* memory scrubber attribute file */
DEVICE_ATTR(sdram_scrub_rate, S_IRUGO | S_IWUSR, mci_sdram_scrub_rate_show,
	mci_sdram_scrub_rate_store);

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_sdram_scrub_rate.attr,
	NULL
};

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

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

static void mci_attr_release(struct device *device)
{
	debugf1("Releasing mci device %s\n", dev_name(device));
}

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


/*
 * 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)
{
	int i, err;

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

	/* get the /sys/devices/system/edac subsys reference */

	mci->dev.type = &mci_attr_type;
	device_initialize(&mci->dev);

	mci->dev.parent = &mci_pdev;
	mci->dev.bus = &mci->bus;
	dev_set_name(&mci->dev, "mc%d", mci->mc_idx);
	dev_set_drvdata(&mci->dev, mci);
	pm_runtime_forbid(&mci->dev);

	/*
	 * The memory controller needs its own bus, in order to avoid
	 * namespace conflicts at /sys/bus/edac.
	 */
	debugf0("creating bus %s\n",mci->bus.name);
	mci->bus.name = kstrdup(dev_name(&mci->dev), GFP_KERNEL);
	err = bus_register(&mci->bus);
	if (err < 0)
		return err;

	debugf0("%s(): creating device %s\n", __func__,
		dev_name(&mci->dev));
	err = device_add(&mci->dev);
	if (err < 0) {
		bus_unregister(&mci->bus);
		kfree(mci->bus.name);
		return err;
	}

	/*
	 * Create the dimm/rank devices
	 */
	for (i = 0; i < mci->tot_dimms; i++) {
		struct dimm_info *dimm = &mci->dimms[i];
		/* Only expose populated DIMMs */
		if (dimm->nr_pages == 0)
			continue;
#ifdef CONFIG_EDAC_DEBUG
		debugf1("%s creating dimm%d, located at ",
			__func__, i);
		if (edac_debug_level >= 1) {
			int lay;
			for (lay = 0; lay < mci->n_layers; lay++)
				printk(KERN_CONT "%s %d ",
					edac_layer_name[mci->layers[lay].type],
					dimm->location[lay]);
			printk(KERN_CONT "\n");
		}
#endif
	}

	err = edac_create_csrow_objects(mci);
	if (err < 0)
		goto fail;

	return 0;

fail:
	for (i--; i >= 0; i--) {
		struct dimm_info *dimm = &mci->dimms[i];
		if (dimm->nr_pages == 0)
			continue;
		put_device(&dimm->dev);
		device_del(&dimm->dev);
	}
	put_device(&mci->dev);
	device_del(&mci->dev);
	bus_unregister(&mci->bus);
	kfree(mci->bus.name);
	return err;
}

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

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

	edac_delete_csrow_objects(mci);

	for (i = 0; i < mci->tot_dimms; i++) {
		struct dimm_info *dimm = &mci->dimms[i];
		if (dimm->nr_pages == 0)
			continue;
		debugf0("%s(): removing device %s\n", __func__,
			dev_name(&dimm->dev));
		put_device(&dimm->dev);
		device_del(&dimm->dev);
	}
}

void edac_unregister_sysfs(struct mem_ctl_info *mci)
{
	debugf1("Unregistering device %s\n", dev_name(&mci->dev));
	put_device(&mci->dev);
	device_del(&mci->dev);
	bus_unregister(&mci->bus);
	kfree(mci->bus.name);
}

static void mc_attr_release(struct device *device)
{
	debugf1("Releasing device %s\n", dev_name(device));
}

static struct device_type mc_attr_type = {
	.release	= mc_attr_release,
};
/*
 * Init/exit code for the module. Basically, creates/removes /sys/class/rc
 */
int __init edac_mc_sysfs_init(void)
{
	struct bus_type *edac_subsys;
	int err;

	/* get the /sys/devices/system/edac subsys reference */
	edac_subsys = edac_get_sysfs_subsys();
	if (edac_subsys == NULL) {
		debugf1("%s() no edac_subsys\n", __func__);
		return -EINVAL;
	}

	mci_pdev.bus = edac_subsys;
	mci_pdev.type = &mc_attr_type;
	device_initialize(&mci_pdev);
	dev_set_name(&mci_pdev, "mc");

	err = device_add(&mci_pdev);
	if (err < 0)
		return err;

	return 0;
}

void __exit edac_mc_sysfs_exit(void)
{
	put_device(&mci_pdev);
	device_del(&mci_pdev);
	edac_put_sysfs_subsys();
}