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Commit 5346c27c authored by Ezequiel Garcia's avatar Ezequiel Garcia Committed by Artem Bityutskiy
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mtd: nandsim: Introduce debugfs infrastructure 



It's more user friendly to report debug information and statistics
through debugfs, than to use printing facilites.

This patch introduces a very minimal debugfs infrastructure
and moves eraseblock wear report to an entry located at:

/sys/kernel/debug/nandsim/wear_report

This means we can remove rptwear option and just let
the user get the wear report when we needs to.

Signed-off-by: default avatarEzequiel Garcia <elezegarcia@gmail.com>
Signed-off-by: default avatarArtem Bityutskiy <artem.bityutskiy@linux.intel.com>
parent e58a66d8

drivers/mtd/nand/nandsim.c

+130 −56
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ 
#include <linux/sched.h>

#include <linux/fs.h>

#include <linux/pagemap.h>

#include <linux/seq_file.h>

#include <linux/debugfs.h>



/* Default simulator parameters values */

#if !defined(CONFIG_NANDSIM_FIRST_ID_BYTE)  || \
@@ -105,7 +107,6 @@ static char *weakblocks = NULL; 
static char *weakpages = NULL;

static unsigned int bitflips = 0;

static char *gravepages = NULL;

static unsigned int rptwear = 0;

static unsigned int overridesize = 0;

static char *cache_file = NULL;

static unsigned int bbt;
@@ -130,7 +131,6 @@ module_param(weakblocks, charp, 0400); 
module_param(weakpages,      charp, 0400);

module_param(bitflips,       uint, 0400);

module_param(gravepages,     charp, 0400);

module_param(rptwear,        uint, 0400);

module_param(overridesize,   uint, 0400);

module_param(cache_file,     charp, 0400);

module_param(bbt,	     uint, 0400);
@@ -162,7 +162,6 @@ MODULE_PARM_DESC(bitflips, "Maximum number of random bit flips per page (z 
MODULE_PARM_DESC(gravepages,     "Pages that lose data [: maximum reads (defaults to 3)]"

				 " separated by commas e.g. 1401:2 means page 1401"

				 " can be read only twice before failing");

MODULE_PARM_DESC(rptwear,        "Number of erases between reporting wear, if not zero");

MODULE_PARM_DESC(overridesize,   "Specifies the NAND Flash size overriding the ID bytes. "

				 "The size is specified in erase blocks and as the exponent of a power of two"

				 " e.g. 5 means a size of 32 erase blocks");
@@ -286,6 +285,11 @@ MODULE_PARM_DESC(bch, "Enable BCH ecc and set how many bits should " 
/* Maximum page cache pages needed to read or write a NAND page to the cache_file */

#define NS_MAX_HELD_PAGES 16



struct nandsim_debug_info {

	struct dentry *dfs_root;

	struct dentry *dfs_wear_report;

};



/*

 * A union to represent flash memory contents and flash buffer.

 */
@@ -365,6 +369,8 @@ struct nandsim { 
	void *file_buf;

	struct page *held_pages[NS_MAX_HELD_PAGES];

	int held_cnt;



	struct nandsim_debug_info dbg;

};



/*
@@ -442,11 +448,123 @@ static LIST_HEAD(grave_pages); 
static unsigned long *erase_block_wear = NULL;

static unsigned int wear_eb_count = 0;

static unsigned long total_wear = 0;

static unsigned int rptwear_cnt = 0;



/* MTD structure for NAND controller */

static struct mtd_info *nsmtd;



static int nandsim_debugfs_show(struct seq_file *m, void *private)

{

	unsigned long wmin = -1, wmax = 0, avg;

	unsigned long deciles[10], decile_max[10], tot = 0;

	unsigned int i;



	/* Calc wear stats */

	for (i = 0; i < wear_eb_count; ++i) {

		unsigned long wear = erase_block_wear[i];

		if (wear < wmin)

			wmin = wear;

		if (wear > wmax)

			wmax = wear;

		tot += wear;

	}



	for (i = 0; i < 9; ++i) {

		deciles[i] = 0;

		decile_max[i] = (wmax * (i + 1) + 5) / 10;

	}

	deciles[9] = 0;

	decile_max[9] = wmax;

	for (i = 0; i < wear_eb_count; ++i) {

		int d;

		unsigned long wear = erase_block_wear[i];

		for (d = 0; d < 10; ++d)

			if (wear <= decile_max[d]) {

				deciles[d] += 1;

				break;

			}

	}

	avg = tot / wear_eb_count;



	/* Output wear report */

	seq_printf(m, "Total numbers of erases:  %lu\n", tot);

	seq_printf(m, "Number of erase blocks:   %u\n", wear_eb_count);

	seq_printf(m, "Average number of erases: %lu\n", avg);

	seq_printf(m, "Maximum number of erases: %lu\n", wmax);

	seq_printf(m, "Minimum number of erases: %lu\n", wmin);

	for (i = 0; i < 10; ++i) {

		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);

		if (from > decile_max[i])

			continue;

		seq_printf(m, "Number of ebs with erase counts from %lu to %lu : %lu\n",

			from,

			decile_max[i],

			deciles[i]);

	}



	return 0;

}



static int nandsim_debugfs_open(struct inode *inode, struct file *file)

{

	return single_open(file, nandsim_debugfs_show, inode->i_private);

}



static const struct file_operations dfs_fops = {

	.open		= nandsim_debugfs_open,

	.read		= seq_read,

	.llseek		= seq_lseek,

	.release	= single_release,

};



/**

 * nandsim_debugfs_create - initialize debugfs

 * @dev: nandsim device description object

 *

 * This function creates all debugfs files for UBI device @ubi. Returns zero in

 * case of success and a negative error code in case of failure.

 */

static int nandsim_debugfs_create(struct nandsim *dev)

{

	struct nandsim_debug_info *dbg = &dev->dbg;

	struct dentry *dent;

	int err;



	if (!IS_ENABLED(CONFIG_DEBUG_FS))

		return 0;



	dent = debugfs_create_dir("nandsim", NULL);

	if (IS_ERR_OR_NULL(dent)) {

		int err = dent ? -ENODEV : PTR_ERR(dent);



		NS_ERR("cannot create \"nandsim\" debugfs directory, err %d\n",

			err);

		return err;

	}

	dbg->dfs_root = dent;



	dent = debugfs_create_file("wear_report", S_IRUSR,

				   dbg->dfs_root, dev, &dfs_fops);

	if (IS_ERR_OR_NULL(dent))

		goto out_remove;

	dbg->dfs_wear_report = dent;



	return 0;



out_remove:

	debugfs_remove_recursive(dbg->dfs_root);

	err = dent ? PTR_ERR(dent) : -ENODEV;

	return err;

}



/**

 * nandsim_debugfs_remove - destroy all debugfs files

 */

static void nandsim_debugfs_remove(struct nandsim *ns)

{

	if (IS_ENABLED(CONFIG_DEBUG_FS))

		debugfs_remove_recursive(ns->dbg.dfs_root);

}



/*

 * Allocate array of page pointers, create slab allocation for an array

 * and initialize the array by NULL pointers.
@@ -911,8 +1029,6 @@ static int setup_wear_reporting(struct mtd_info *mtd) 
{

	size_t mem;



	if (!rptwear)

		return 0;

	wear_eb_count = div_u64(mtd->size, mtd->erasesize);

	mem = wear_eb_count * sizeof(unsigned long);

	if (mem / sizeof(unsigned long) != wear_eb_count) {
@@ -929,64 +1045,18 @@ static int setup_wear_reporting(struct mtd_info *mtd) 


static void update_wear(unsigned int erase_block_no)

{

	unsigned long wmin = -1, wmax = 0, avg;

	unsigned long deciles[10], decile_max[10], tot = 0;

	unsigned int i;



	if (!erase_block_wear)

		return;

	total_wear += 1;

	/*

	 * TODO: Notify this through a debugfs entry,

	 * instead of showing an error message.

	 */

	if (total_wear == 0)

		NS_ERR("Erase counter total overflow\n");

	erase_block_wear[erase_block_no] += 1;

	if (erase_block_wear[erase_block_no] == 0)

		NS_ERR("Erase counter overflow for erase block %u\n", erase_block_no);

	rptwear_cnt += 1;

	if (rptwear_cnt < rptwear)

		return;

	rptwear_cnt = 0;

	/* Calc wear stats */

	for (i = 0; i < wear_eb_count; ++i) {

		unsigned long wear = erase_block_wear[i];

		if (wear < wmin)

			wmin = wear;

		if (wear > wmax)

			wmax = wear;

		tot += wear;

	}

	for (i = 0; i < 9; ++i) {

		deciles[i] = 0;

		decile_max[i] = (wmax * (i + 1) + 5) / 10;

	}

	deciles[9] = 0;

	decile_max[9] = wmax;

	for (i = 0; i < wear_eb_count; ++i) {

		int d;

		unsigned long wear = erase_block_wear[i];

		for (d = 0; d < 10; ++d)

			if (wear <= decile_max[d]) {

				deciles[d] += 1;

				break;

			}

	}

	avg = tot / wear_eb_count;

	/* Output wear report */

	NS_INFO("*** Wear Report ***\n");

	NS_INFO("Total numbers of erases:  %lu\n", tot);

	NS_INFO("Number of erase blocks:   %u\n", wear_eb_count);

	NS_INFO("Average number of erases: %lu\n", avg);

	NS_INFO("Maximum number of erases: %lu\n", wmax);

	NS_INFO("Minimum number of erases: %lu\n", wmin);

	for (i = 0; i < 10; ++i) {

		unsigned long from = (i ? decile_max[i - 1] + 1 : 0);

		if (from > decile_max[i])

			continue;

		NS_INFO("Number of ebs with erase counts from %lu to %lu : %lu\n",

			from,

			decile_max[i],

			deciles[i]);

	}

	NS_INFO("*** End of Wear Report ***\n");

}



/*
@@ -2330,6 +2400,9 @@ static int __init ns_init_module(void) 
	if ((retval = setup_wear_reporting(nsmtd)) != 0)

		goto err_exit;



	if ((retval = nandsim_debugfs_create(nand)) != 0)

		goto err_exit;



	if ((retval = init_nandsim(nsmtd)) != 0)

		goto err_exit;
@@ -2369,6 +2442,7 @@ static void __exit ns_cleanup_module(void) 
	struct nandsim *ns = ((struct nand_chip *)nsmtd->priv)->priv;

	int i;



	nandsim_debugfs_remove(ns);

	free_nandsim(ns);    /* Free nandsim private resources */

	nand_release(nsmtd); /* Unregister driver */

	for (i = 0;i < ARRAY_SIZE(ns->partitions); ++i)