[PATCH 1/2] [MTD] [JFFS2] MLC NAND support

[AYYANARPONNUSAMY GANGHEYAMOORTHY <moorthy.apg@samsung.com>]

Currently JFFS2 writes twice to the first page of the block,
cleanmarker in OOB area and data in main area, which prevents
JFFS2 from being used on MLC devices which have NOP count 1.
This patch reserves the first page only for the cleanmarker.

Note : With robustness testing, one test board out six has
given a BUG. We are looking into it.

Signed-off-by: Rajshekar H Payagond <rajshekar.hp@samsung.com>
---
--- a/fs/jffs2/build.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/build.c	2008-09-01 13:39:56.000000000 +0530
@@ -330,7 +330,11 @@ int jffs2_do_mount_fs(struct jffs2_sb_in
 	int i;
 	int size;
 
-	c->free_size = c->flash_size;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH)
+		c->free_size = 0;
+	else
+		c->free_size = c->flash_size;
+
 	c->nr_blocks = c->flash_size / c->sector_size;
 	size = sizeof(struct jffs2_eraseblock) * c->nr_blocks;
 #ifndef __ECOS
@@ -346,7 +350,14 @@ int jffs2_do_mount_fs(struct jffs2_sb_in
 	for (i=0; i<c->nr_blocks; i++) {
 		INIT_LIST_HEAD(&c->blocks[i].list);
 		c->blocks[i].offset = i * c->sector_size;
-		c->blocks[i].free_size = c->sector_size;
+		if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+			c->blocks[i].free_size =
+					c->sector_size - c->wbuf_pagesize;
+			c->blocks[i].used_size = c->wbuf_pagesize;
+			c->free_size +=  c->blocks[i].free_size;
+			c->used_size += c->blocks[i].used_size;
+		} else
+			c->blocks[i].free_size = c->sector_size;
 	}
 
 	INIT_LIST_HEAD(&c->clean_list);
--- a/fs/jffs2/debug.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/debug.c	2008-09-01 13:39:56.000000000 +0530
@@ -307,6 +307,9 @@ __jffs2_dbg_acct_paranoia_check_nolock(s
 	uint32_t my_dirty_size = 0;
 	struct jffs2_raw_node_ref *ref2 = jeb->first_node;
 
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH)
+		my_used_size = c->wbuf_pagesize;
+
 	while (ref2) {
 		uint32_t totlen = ref_totlen(c, jeb, ref2);
 
--- a/fs/jffs2/erase.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/erase.c	2008-09-01 13:39:56.000000000 +0530
@@ -454,13 +454,21 @@ static void jffs2_mark_erased_block(stru
 		}
 	}
 	/* Everything else got zeroed before the erase */
-	jeb->free_size = c->sector_size;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+		jeb->free_size = c->sector_size - c->wbuf_pagesize;
+		jeb->used_size = c->wbuf_pagesize;
+	} else
+		jeb->free_size = c->sector_size;
 
 	mutex_lock(&c->erase_free_sem);
 	spin_lock(&c->erase_completion_lock);
 
 	c->erasing_size -= c->sector_size;
-	c->free_size += c->sector_size;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+		c->free_size += c->sector_size - c->wbuf_pagesize;
+		c->used_size += c->wbuf_pagesize;
+	} else
+		c->free_size += c->sector_size;
 
 	/* Account for cleanmarker now, if it's in-band */
 	if (c->cleanmarker_size && !jffs2_cleanmarker_oob(c))
--- a/fs/jffs2/gc.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/gc.c	2008-09-01 13:39:56.000000000 +0530
@@ -237,9 +237,19 @@ int jffs2_garbage_collect_pass(struct jf
 	D1(if (c->nextblock)
 	   printk(KERN_DEBUG "Nextblock at  %08x, used_size %08x, dirty_size %08x, wasted_size %08x, free_size %08x\n", c->nextblock->offset, c->nextblock->used_size, c->nextblock->dirty_size, c->nextblock->wasted_size, c->nextblock->free_size));
 
-	if (!jeb->used_size) {
-		mutex_unlock(&c->alloc_sem);
-		goto eraseit;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+		if (jeb->used_size <= c->wbuf_pagesize) {
+			mutex_unlock(&c->alloc_sem);
+			goto eraseit;
+		}
+
+	}
+
+	else{
+		if (!jeb->used_size) {
+			mutex_unlock(&c->alloc_sem);
+			goto eraseit;
+		}
 	}
 
 	raw = jeb->gc_node;
@@ -429,13 +439,32 @@ int jffs2_garbage_collect_pass(struct jf
 	spin_lock(&c->erase_completion_lock);
 
  eraseit:
-	if (c->gcblock && !c->gcblock->used_size) {
-		D1(printk(KERN_DEBUG "Block at 0x%08x completely obsoleted by GC. Moving to erase_pending_list\n", c->gcblock->offset));
-		/* We're GC'ing an empty block? */
-		list_add_tail(&c->gcblock->list, &c->erase_pending_list);
-		c->gcblock = NULL;
-		c->nr_erasing_blocks++;
-		jffs2_erase_pending_trigger(c);
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+		if (c->gcblock && (c->gcblock->used_size <= c->wbuf_pagesize)) {
+			D1(printk(KERN_DEBUG "Block at 0x%08x completely"
+				" obsoleted by GC. Moving to erase_pending_list\n"
+				, c->gcblock->offset));
+			/* We're GC'ing an empty block? */
+			list_add_tail(&c->gcblock->list,
+					&c->erase_pending_list);
+			c->gcblock = NULL;
+			c->nr_erasing_blocks++;
+			jffs2_erase_pending_trigger(c);
+		}
+	}
+
+	else{
+		if (c->gcblock && !c->gcblock->used_size) {
+			D1(printk(KERN_DEBUG "Block at 0x%08x completely"
+				" obsoleted by GC. Moving to erase_pending_list\n"
+				, c->gcblock->offset));
+			/* We're GC'ing an empty block? */
+			list_add_tail(&c->gcblock->list,
+					&c->erase_pending_list);
+			c->gcblock = NULL;
+			c->nr_erasing_blocks++;
+			jffs2_erase_pending_trigger(c);
+		}
 	}
 	spin_unlock(&c->erase_completion_lock);
 
--- a/fs/jffs2/nodelist.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/nodelist.c	2008-09-01 13:39:56.000000000 +0530
@@ -634,7 +634,11 @@ struct jffs2_raw_node_ref *jffs2_link_no
 
 	if (!jeb->first_node) {
 		jeb->first_node = ref;
-		BUG_ON(ref_offset(ref) != jeb->offset);
+		if (c->mtd->flags == MTD_CAP_MLCNANDFLASH)
+			BUG_ON(ref_offset(ref) !=
+						jeb->offset + c->wbuf_pagesize);
+		else
+			BUG_ON(ref_offset(ref) != jeb->offset);
 	} else if (unlikely(ref_offset(ref) != jeb->offset + c->sector_size - jeb->free_size)) {
 		uint32_t last_len = ref_totlen(c, jeb, jeb->last_node);
 
--- a/fs/jffs2/nodemgmt.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/nodemgmt.c	2008-09-01 16:15:47.000000000 +0530
@@ -362,16 +362,25 @@ static int jffs2_do_reserve_space(struct
 	}
 
 	if (!jeb) {
-
 		ret = jffs2_find_nextblock(c);
 		if (ret)
 			return ret;
 
 		jeb = c->nextblock;
+		if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+			if (jeb->free_size != c->sector_size -
+				c->cleanmarker_size - c->wbuf_pagesize) {
+				printk(KERN_WARNING "Eep. Block 0x%08x taken from free_list had free_size of 0x%08x!!\n", jeb->offset, jeb->free_size);
+				goto restart;
+			}
+		}
 
-		if (jeb->free_size != c->sector_size - c->cleanmarker_size) {
-			printk(KERN_WARNING "Eep. Block 0x%08x taken from free_list had free_size of 0x%08x!!\n", jeb->offset, jeb->free_size);
-			goto restart;
+		else{
+			if (jeb->free_size != c->sector_size -
+					c->cleanmarker_size) {
+				printk(KERN_WARNING "Eep. Block 0x%08x taken from free_list had free_size of 0x%08x!!\n", jeb->offset, jeb->free_size);
+				goto restart;
+			}
 		}
 	}
 	/* OK, jeb (==c->nextblock) is now pointing at a block which definitely has
--- a/fs/jffs2/scan.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/scan.c	2008-09-01 13:39:56.000000000 +0530
@@ -534,7 +534,10 @@ static int jffs2_scan_eraseblock (struct
 		}
 	}
 
-	buf_ofs = jeb->offset;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH)
+		buf_ofs = jeb->offset + c->wbuf_pagesize;
+	else
+		buf_ofs = jeb->offset;
 
 	if (!buf_size) {
 		/* This is the XIP case -- we're reading _directly_ from the flash chip */
@@ -582,7 +585,10 @@ static int jffs2_scan_eraseblock (struct
 	}
 
 	/* Now ofs is a complete physical flash offset as it always was... */
-	ofs += jeb->offset;
+	if (c->mtd->flags == MTD_CAP_MLCNANDFLASH)
+		ofs += jeb->offset + c->wbuf_pagesize;
+	else
+		ofs += jeb->offset;
 
 	noise = 10;
 
--- a/fs/jffs2/wbuf.c	2008-08-24 04:48:32.000000000 +0530
+++ b/fs/jffs2/wbuf.c	2008-09-01 13:39:56.000000000 +0530
@@ -873,6 +873,13 @@ int jffs2_flash_writev(struct jffs2_sb_i
 			vlen -= wbuf_retlen;
 			outvec_to += wbuf_retlen;
 			c->wbuf_ofs = outvec_to;
+			if (c->mtd->flags == MTD_CAP_MLCNANDFLASH) {
+				/* adjust write buffer offset,
+				 * else we get a non contiguous write bug
+				 */
+				if (!(c->wbuf_ofs % c->sector_size))
+					c->wbuf_ofs = 0xffffffff;
+			}
 			donelen += wbuf_retlen;
 			v += wbuf_retlen;
 		}
--- a/include/mtd/mtd-abi.h	2008-09-02 13:51:09.000000000 +0530
+++ b/include/mtd/mtd-abi.h	2008-09-02 13:51:42.000000000 +0530
@@ -28,12 +28,14 @@ struct mtd_oob_buf {
 #define MTD_BIT_WRITEABLE	0x800	/* Single bits can be flipped */
 #define MTD_NO_ERASE		0x1000	/* No erase necessary */
 #define MTD_POWERUP_LOCK	0x2000	/* Always locked after reset */
+#define MTD_WRITABLE_ONCE	0x4000
 
 // Some common devices / combinations of capabilities
 #define MTD_CAP_ROM		0
 #define MTD_CAP_RAM		(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE)
 #define MTD_CAP_NORFLASH	(MTD_WRITEABLE | MTD_BIT_WRITEABLE)
 #define MTD_CAP_NANDFLASH	(MTD_WRITEABLE)
+#define MTD_CAP_MLCNANDFLASH	(MTD_WRITEABLE | MTD_WRITABLE_ONCE)
 
 /* ECC byte placement */
 #define MTD_NANDECC_OFF		0	// Switch off ECC (Not recommended)