[PATCH] nandsim: Introduce debugfs infrastructure

Ezequiel Garcia
2012-11-25T01:52:06Z

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 read the wear report when we needs to.

Cc: Artem Bityutskiy <dedekind1@gmail.com>
Signed-off-by: Ezequiel Garcia <elezegarcia@gmail.com>
---
drivers/mtd/nand/nandsim.c | 188 +++++++++++++++++++++++++++++++-------------
1 files changed, 132 insertions(+), 56 deletions(-)

diff --git a/drivers/mtd/nand/nandsim.c b/drivers/mtd/nand/nandsim.c
index a932c48..b25dcfc 100644
--- a/drivers/mtd/nand/nandsim.c
+++ b/drivers/mtd/nand/nandsim.c
@@ -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 +448,125 @@ 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;
+ /*struct nandsim *dev = (struct nandsim *)private;*/
+ /*struct nandsim_debug_info *dbg = &dev->dbg;*/
+
+ /* 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.
+ */
+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_IWUSR,
+ 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
+ */
+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 +1031,6 @@ 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 +1047,18 @@ 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 +2402,9 @@ 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 +2444,7 @@ 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)
--
1.7.8.6