edac_device.c

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/*
 * edac_device.c
 * (C) 2007 www.douglaskthompson.com
 *
 * This file may be distributed under the terms of the
 * GNU General Public License.
 *
 * Written by Doug Thompson <[e-mail]>
 *
 * edac_device API implementation
 * 19 Jan 2007
 */

#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/jiffies.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sysdev.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"

/* lock for the list: 'edac_device_list', manipulation of this list
 * is protected by the 'device_ctls_mutex' lock
 */
static DEFINE_MUTEX(device_ctls_mutex);
static struct list_head edac_device_list = LIST_HEAD_INIT(edac_device_list);

#ifdef CONFIG_EDAC_DEBUG
static void edac_device_dump_device(struct edac_device_ctl_info *edac_dev)
{
	debugf3("\tedac_dev = %p dev_idx=%d \n", edac_dev, edac_dev->dev_idx);
	debugf4("\tedac_dev->edac_check = %p\n", edac_dev->edac_check);
	debugf3("\tdev = %p\n", edac_dev->dev);
	debugf3("\tmod_name:ctl_name = %s:%s\n",
		edac_dev->mod_name, edac_dev->ctl_name);
	debugf3("\tpvt_info = %p\n\n", edac_dev->pvt_info);
}
#endif				/* CONFIG_EDAC_DEBUG */


/*
 * edac_device_alloc_ctl_info()
 *	Allocate a new edac device control info structure
 *
 *	The control structure is allocated in complete chunk
 *	from the OS. It is in turn sub allocated to the
 *	various objects that compose the struture
 *
 *	The structure has a 'nr_instance' array within itself.
 *	Each instance represents a major component
 *		Example:  L1 cache and L2 cache are 2 instance components
 *
 *	Within each instance is an array of 'nr_blocks' blockoffsets
 */
struct edac_device_ctl_info *edac_device_alloc_ctl_info(
	unsigned sz_private,
	char *edac_device_name, unsigned nr_instances,
	char *edac_block_name, unsigned nr_blocks,
	unsigned offset_value,		/* zero, 1, or other based offset */
	struct edac_dev_sysfs_block_attribute *attrib_spec, unsigned nr_attrib,
	int device_index)
{
	struct edac_device_ctl_info *dev_ctl;
	struct edac_device_instance *dev_inst, *inst;
	struct edac_device_block *dev_blk, *blk_p, *blk;
	struct edac_dev_sysfs_block_attribute *dev_attrib, *attrib_p, *attrib;
	unsigned total_size;
	unsigned count;
	unsigned instance, block, attr;
	void *pvt;
	int err;

	debugf4("%s() instances=%d blocks=%d\n",
		__func__, nr_instances, nr_blocks);

	/* Calculate the size of memory we need to allocate AND
	 * determine the offsets of the various item arrays
	 * (instance,block,attrib) from the start of an  allocated structure.
	 * We want the alignment of each item  (instance,block,attrib)
	 * to be at least as stringent as what the compiler would
	 * provide if we could simply hardcode everything into a single struct.
	 */
	dev_ctl = (struct edac_device_ctl_info *)NULL;

	/* Calc the 'end' offset past end of ONE ctl_info structure
	 * which will become the start of the 'instance' array
	 */
	dev_inst = edac_align_ptr(&dev_ctl[1], sizeof(*dev_inst));

	/* Calc the 'end' offset past the instance array within the ctl_info
	 * which will become the start of the block array
	 */
	dev_blk = edac_align_ptr(&dev_inst[nr_instances], sizeof(*dev_blk));

	/* Calc the 'end' offset past the dev_blk array
	 * which will become the start of the attrib array, if any.
	 */
	count = nr_instances * nr_blocks;
	dev_attrib = edac_align_ptr(&dev_blk[count], sizeof(*dev_attrib));

	/* Check for case of when an attribute array is specified */
	if (nr_attrib > 0) {
		/* calc how many nr_attrib we need */
		count *= nr_attrib;

		/* Calc the 'end' offset past the attributes array */
		pvt = edac_align_ptr(&dev_attrib[count], sz_private);
	} else {
		/* no attribute array specificed */
		pvt = edac_align_ptr(dev_attrib, sz_private);
	}

	/* 'pvt' now points to where the private data area is.
	 * At this point 'pvt' (like dev_inst,dev_blk and dev_attrib)
	 * is baselined at ZERO
	 */
	total_size = ((unsigned long)pvt) + sz_private;

	/* Allocate the amount of memory for the set of control structures */
	dev_ctl = kzalloc(total_size, GFP_KERNEL);
	if (dev_ctl == NULL)
		return NULL;

	/* Adjust pointers so they point within the actual memory we
	 * just allocated rather than an imaginary chunk of memory
	 * located at address 0.
	 * 'dev_ctl' points to REAL memory, while the others are
	 * ZERO based and thus need to be adjusted to point within
	 * the allocated memory.
	 */
	dev_inst = (struct edac_device_instance *)
		(((char *)dev_ctl) + ((unsigned long)dev_inst));
	dev_blk = (struct edac_device_block *)
		(((char *)dev_ctl) + ((unsigned long)dev_blk));
	dev_attrib = (struct edac_dev_sysfs_block_attribute *)
		(((char *)dev_ctl) + ((unsigned long)dev_attrib));
	pvt = sz_private ? (((char *)dev_ctl) + ((unsigned long)pvt)) : NULL;

	/* Begin storing the information into the control info structure */
	dev_ctl->dev_idx = device_index;
	dev_ctl->nr_instances = nr_instances;
	dev_ctl->instances = dev_inst;
	dev_ctl->pvt_info = pvt;

	/* Name of this edac device */
	snprintf(dev_ctl->name,sizeof(dev_ctl->name),"%s",edac_device_name);

	debugf4("%s() edac_dev=%p next after end=%p\n",
		__func__, dev_ctl, pvt + sz_private );

	/* Initialize every Instance */
	for (instance = 0; instance < nr_instances; instance++) {
		inst = &dev_inst[instance];
		inst->ctl = dev_ctl;
		inst->nr_blocks = nr_blocks;
		blk_p = &dev_blk[instance * nr_blocks];
		inst->blocks = blk_p;

		/* name of this instance */
		snprintf(inst->name, sizeof(inst->name),
			 "%s%u", edac_device_name, instance);

		/* Initialize every block in each instance */
		for (block = 0; block < nr_blocks; block++) {
			blk = &blk_p[block];
			blk->instance = inst;
			snprintf(blk->name, sizeof(blk->name),
				 "%s%d", edac_block_name, block+offset_value);

			debugf4("%s() instance=%d inst_p=%p block=#%d "
				"block_p=%p name='%s'\n",
				__func__, instance, inst, block,
				blk, blk->name);

			/* if there are NO attributes OR no attribute pointer
			 * then continue on to next block iteration
			 */
			if ((nr_attrib == 0) || (attrib_spec == NULL))
				continue;

			/* setup the attribute array for this block */
			blk->nr_attribs = nr_attrib;
			attrib_p = &dev_attrib[block*nr_instances*nr_attrib];
			blk->block_attributes = attrib_p;

			debugf4("%s() THIS BLOCK_ATTRIB=%p\n",
				__func__, blk->block_attributes);

			/* Initialize every user specified attribute in this
			 * block with the data the caller passed in
			 * Each block gets its own copy of pointers,
			 * and its unique 'value'
			 */
			for (attr = 0; attr < nr_attrib; attr++) {
				attrib = &attrib_p[attr];

				/* populate the unique per attrib
				 * with the code pointers and info
				 */
				attrib->attr = attrib_spec[attr].attr;
				attrib->show = attrib_spec[attr].show;
				attrib->store = attrib_spec[attr].store;

				attrib->block = blk;	/* up link */

				debugf4("%s() alloc-attrib=%p attrib_name='%s' "
					"attrib-spec=%p spec-name=%s\n",
					__func__, attrib, attrib->attr.name,
					&attrib_spec[attr],
					attrib_spec[attr].attr.name
					);
			}
		}
	}

	/* Mark this instance as merely ALLOCATED */
	dev_ctl->op_state = OP_ALLOC;

	/*
	 * Initialize the 'root' kobj for the edac_device controller
	 */
	err = edac_device_register_sysfs_main_kobj(dev_ctl);
	if (err) {
		kfree(dev_ctl);
		return NULL;
	}

	/* at this point, the root kobj is valid, and in order to
	 * 'free' the object, then the function:
	 *	edac_device_unregister_sysfs_main_kobj() must be called
	 * which will perform kobj unregistration and the actual free
	 * will occur during the kobject callback operation
	 */

	return dev_ctl;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_ctl_info);

/*
 * edac_device_free_ctl_info()
 *	frees the memory allocated by the edac_device_alloc_ctl_info()
 *	function
 */
void edac_device_free_ctl_info(struct edac_device_ctl_info *ctl_info)
{
	edac_device_unregister_sysfs_main_kobj(ctl_info);
}
EXPORT_SYMBOL_GPL(edac_device_free_ctl_info);

/*
 * find_edac_device_by_dev
 *	scans the edac_device list for a specific 'struct device *'
 *
 *	lock to be held prior to call:	device_ctls_mutex
 *
 *	Return:
 *		pointer to control structure managing 'dev'
 *		NULL if not found on list
 */
static struct edac_device_ctl_info *find_edac_device_by_dev(struct device *dev)
{
	struct edac_device_ctl_info *edac_dev;
	struct list_head *item;

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

	list_for_each(item, &edac_device_list) {
		edac_dev = list_entry(item, struct edac_device_ctl_info, link);

		if (edac_dev->dev == dev)
			return edac_dev;
	}

	return NULL;
}

/*
 * add_edac_dev_to_global_list
 *	Before calling this function, caller must
 *	assign a unique value to edac_dev->dev_idx.
 *
 *	lock to be held prior to call:	device_ctls_mutex
 *
 *	Return:
 *		0 on success
 *		1 on failure.
 */
static int add_edac_dev_to_global_list(struct edac_device_ctl_info *edac_dev)
{
	struct list_head *item, *insert_before;
	struct edac_device_ctl_info *rover;

	insert_before = &edac_device_list;

	/* Determine if already on the list */
	rover = find_edac_device_by_dev(edac_dev->dev);
	if (unlikely(rover != NULL))
		goto fail0;

	/* Insert in ascending order by 'dev_idx', so find position */
	list_for_each(item, &edac_device_list) {
		rover = list_entry(item, struct edac_device_ctl_info, link);

		if (rover->dev_idx >= edac_dev->dev_idx) {
			if (unlikely(rover->dev_idx == edac_dev->dev_idx))
				goto fail1;

			insert_before = item;
			break;
		}
	}

	list_add_tail_rcu(&edac_dev->link, insert_before);
	return 0;

fail0:
	edac_printk(KERN_WARNING, EDAC_MC,
			"%s (%s) %s %s already assigned %d\n",
			rover->dev->bus_id, dev_name(rover),
			rover->mod_name, rover->ctl_name, rover->dev_idx);
	return 1;

fail1:
	edac_printk(KERN_WARNING, EDAC_MC,
			"bug in low-level driver: attempt to assign\n"
			"    duplicate dev_idx %d in %s()\n", rover->dev_idx,
			__func__);
	return 1;
}

/*
 * complete_edac_device_list_del
 *
 *	callback function when reference count is zero
 */
static void complete_edac_device_list_del(struct rcu_head *head)
{
	struct edac_device_ctl_info *edac_dev;

	edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
	INIT_LIST_HEAD(&edac_dev->link);
	complete(&edac_dev->removal_complete);
}

/*
 * del_edac_device_from_global_list
 *
 *	remove the RCU, setup for a callback call,
 *	then wait for the callback to occur
 */
static void del_edac_device_from_global_list(struct edac_device_ctl_info
						*edac_device)
{
	list_del_rcu(&edac_device->link);

	init_completion(&edac_device->removal_complete);
	call_rcu(&edac_device->rcu, complete_edac_device_list_del);
	wait_for_completion(&edac_device->removal_complete);
}

/**