/*
 * 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(sizeof(*mci_pdev), GFP_KERNEL);
	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);
}