/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 * Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include <linux/crc32.h>
#include <linux/sched.h>
#include <linux/pagemap.h>
#include "nodelist.h"

struct erase_priv_struct {
	struct jffs2_eraseblock *jeb;
	struct jffs2_sb_info *c;
};

#ifndef __ECOS
static void jffs2_erase_callback(struct erase_info *);
#endif
static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset);
static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);
static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb);

static void jffs2_erase_block(struct jffs2_sb_info *c,
			      struct jffs2_eraseblock *jeb)
{
	int ret;
	uint32_t bad_offset;
#ifdef __ECOS
       ret = jffs2_flash_erase(c, jeb);
       if (!ret) {
	       jffs2_erase_succeeded(c, jeb);
	       return;
       }
       bad_offset = jeb->offset;
#else /* Linux */
	struct erase_info *instr;

	jffs2_dbg(1, "%s(): erase block %#08x (range %#08x-%#08x)\n",
		  __func__,
		  jeb->offset, jeb->offset, jeb->offset + c->sector_size);
	instr = kmalloc(sizeof(struct erase_info) + sizeof(struct erase_priv_struct), GFP_KERNEL);
	if (!instr) {
		pr_warn("kmalloc for struct erase_info in jffs2_erase_block failed. Refiling block for later\n");
		mutex_lock(&c->erase_free_sem);
		spin_lock(&c->erase_completion_lock);
		list_move(&jeb->list, &c->erase_pending_list);
		c->erasing_size -= c->sector_size;
		c->dirty_size += c->sector_size;
		jeb->dirty_size = c->sector_size;
		spin_unlock(&c->erase_completion_lock);
		mutex_unlock(&c->erase_free_sem);
		return;
	}

	memset(instr, 0, sizeof(*instr));

	instr->mtd = c->mtd;
	instr->addr = jeb->offset;
	instr->len = c->sector_size;
	instr->callback = jffs2_erase_callback;
	instr->priv = (unsigned long)(&instr[1]);

	((struct erase_priv_struct *)instr->priv)->jeb = jeb;
	((struct erase_priv_struct *)instr->priv)->c = c;
#if defined(CONFIG_BCM_KF_MTD_BCMNAND)
	if (c->mtd->flags & MTD_NAND_NOP1)
	{ /* check if block is empty first, may not have to erase. must do this at the time of erasing a block
	and cannot put this in jffs2_check_nand_cleanmarker since that routine is called often, even when not
	attempting to erase the block and even in non writeable JFFS2 partition. Do this only for NOP=1 device since
	device is not allowed to have write to spare area only (JFFS2 clean marker inserted after erase) and thus
	there will be an erase attempt at every boot when JFFS2 checks for erased blocks and the missing clean
	marker. Do not do erase check for NOP > 1 devices since they are allowed to have a JFFS2 clean marker
	inserted and by not doing the erase check this will save time */
		struct mtd_oob_ops ops;
		loff_t page_offset;
		int i, dirty = 0;
		unsigned char buf[c->mtd->writesize + c->mtd->oobsize];

		for (page_offset = 0; !dirty && (page_offset < c->mtd->erasesize); page_offset += c->mtd->writesize)
		{ // check to see that ECC is empty to determine if page is erased
			ops.mode = MTD_OPS_RAW;
			ops.ooblen = c->mtd->oobsize;
			ops.oobbuf = buf + c->mtd->writesize;
			ops.len = c->mtd->writesize;
			ops.ooboffs = ops.retlen = ops.oobretlen = 0;
			ops.datbuf = buf;

			i = mtd_read_oob(c->mtd, jeb->offset + page_offset, &ops);

			if (i || (ops.oobretlen != ops.ooblen) || (ops.retlen != ops.len))
				dirty = 1;

			for (i = 0; !dirty && (i < (c->mtd->writesize + c->mtd->oobsize)); i++)
				if (buf[i] != 0xFF)
					dirty = 1;
		}
		if (!dirty)
		{
			instr->state = MTD_ERASE_DONE;
			jffs2_erase_callback(instr);
			return;
		}
	}
#endif

	ret = mtd_erase(c->mtd, instr);
	if (!ret)
		return;

	bad_offset = instr->fail_addr;
	kfree(instr);
#endif /* __ECOS */

	if (ret == -ENOMEM || ret == -EAGAIN) {
		/* Erase failed immediately. Refile it on the list */
		jffs2_dbg(1, "Erase at 0x%08x failed: %d. Refiling on erase_pending_list\n",
			  jeb->offset, ret);
		mutex_lock(&c->erase_free_sem);
		spin_lock(&c->erase_completion_lock);
		list_move(&jeb->list, &c->erase_pending_list);
		c->erasing_size -= c->sector_size;
		c->dirty_size += c->sector_size;
		jeb->dirty_size = c->sector_size;
		spin_unlock(&c->erase_completion_lock);
		mutex_unlock(&c->erase_free_sem);
		return;
	}

	if (ret == -EROFS)
		pr_warn("Erase at 0x%08x failed immediately: -EROFS. Is the sector locked?\n",
			jeb->offset);
	else
		pr_warn("Erase at 0x%08x failed immediately: errno %d\n",
			jeb->offset, ret);

	jffs2_erase_failed(c, jeb, bad_offset);
}

int jffs2_erase_pending_blocks(struct jffs2_sb_info *c, int count)
{
	struct jffs2_eraseblock *jeb;
	int work_done = 0;

	mutex_lock(&c->erase_free_sem);

	spin_lock(&c->erase_completion_lock);

	while (!list_empty(&c->erase_complete_list) ||
	       !list_empty(&c->erase_pending_list)) {

		if (!list_empty(&c->erase_complete_list)) {
			jeb = list_entry(c->erase_complete_list.next, struct jffs2_eraseblock, list);
			list_move(&jeb->list, &c->erase_checking_list);
			spin_unlock(&c->erase_completion_lock);
			mutex_unlock(&c->erase_free_sem);
			jffs2_mark_erased_block(c, jeb);

			work_done++;
			if (!--count) {
				jffs2_dbg(1, "Count reached. jffs2_erase_pending_blocks leaving\n");
				goto done;
			}

		} else if (!list_empty(&c->erase_pending_list)) {
			jeb = list_entry(c->erase_pending_list.next, struct jffs2_eraseblock, list);
			jffs2_dbg(1, "Starting erase of pending block 0x%08x\n",
				  jeb->offset);
			list_del(&jeb->list);
			c->erasing_size += c->sector_size;
			c->wasted_size -= jeb->wasted_size;
			c->free_size -= jeb->free_size;
			c->used_size -= jeb->used_size;
			c->dirty_size -= jeb->dirty_size;
			jeb->wasted_size = jeb->used_size = jeb->dirty_size = jeb->free_size = 0;
			jffs2_free_jeb_node_refs(c, jeb);
			list_add(&jeb->list, &c->erasing_list);
			spin_unlock(&c->erase_completion_lock);
			mutex_unlock(&c->erase_free_sem);

			jffs2_erase_block(c, jeb);

		} else {
			BUG();
		}

		/* Be nice */
		cond_resched();
		mutex_lock(&c->erase_free_sem);
		spin_lock(&c->erase_completion_lock);
	}

	spin_unlock(&c->erase_completion_lock);
	mutex_unlock(&c->erase_free_sem);
 done:
	jffs2_dbg(1, "jffs2_erase_pending_blocks completed\n");
	return work_done;
}

static void jffs2_erase_succeeded(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	jffs2_dbg(1, "Erase completed successfully at 0x%08x\n", jeb->offset);
	mutex_lock(&c->erase_free_sem);
	spin_lock(&c->erase_completion_lock);
	list_move_tail(&jeb->list, &c->erase_complete_list);
	/* Wake the GC thread to mark them clean */
	jffs2_garbage_collect_trigger(c);
	spin_unlock(&c->erase_completion_lock);
	mutex_unlock(&c->erase_free_sem);
	wake_up(&c->erase_wait);
}

static void jffs2_erase_failed(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
{
	/* For NAND, if the failure did not occur at the device level for a
	   specific physical page, don't bother updating the bad block table. */
	if (jffs2_cleanmarker_oob(c) && (bad_offset != (uint32_t)MTD_FAIL_ADDR_UNKNOWN)) {
		/* We had a device-level failure to erase.  Let's see if we've
		   failed too many times. */
		if (!jffs2_write_nand_badblock(c, jeb, bad_offset)) {
			/* We'd like to give this block another try. */
			mutex_lock(&c->erase_free_sem);
			spin_lock(&c->erase_completion_lock);
			list_move(&jeb->list, &c->erase_pending_list);
			c->erasing_size -= c->sector_size;
			c->dirty_size += c->sector_size;
			jeb->dirty_size = c->sector_size;
			spin_unlock(&c->erase_completion_lock);
			mutex_unlock(&c->erase_free_sem);
			return;
		}
	}

	mutex_lock(&c->erase_free_sem);
	spin_lock(&c->erase_completion_lock);
	c->erasing_size -= c->sector_size;
	c->bad_size += c->sector_size;
	list_move(&jeb->list, &c->bad_list);
	c->nr_erasing_blocks--;
	spin_unlock(&c->erase_completion_lock);
	mutex_unlock(&c->erase_free_sem);
	wake_up(&c->erase_wait);
}

#ifndef __ECOS
static void jffs2_erase_callback(struct erase_info *instr)
{
	struct erase_priv_struct *priv = (void *)instr->priv;

	if(instr->state != MTD_ERASE_DONE) {
		pr_warn("Erase at 0x%08llx finished, but state != MTD_ERASE_DONE. State is 0x%x instead.\n",
			(unsigned long long)instr->addr, instr->state);
		jffs2_erase_failed(priv->c, priv->jeb, instr->fail_addr);
	} else {
		jffs2_erase_succeeded(priv->c, priv->jeb);
	}
	kfree(instr);
}
#endif /* !__ECOS */

/* Hmmm. Maybe we should accept the extra space it takes and make
   this a standard doubly-linked list? */
static inline void jffs2_remove_node_refs_from_ino_list(struct jffs2_sb_info *c,
			struct jffs2_raw_node_ref *ref, struct jffs2_eraseblock *jeb)
{
	struct jffs2_inode_cache *ic = NULL;
	struct jffs2_raw_node_ref **prev;

	prev = &ref->next_in_ino;

	/* Walk the inode's list once, removing any nodes from this eraseblock */
	while (1) {
		if (!(*prev)->next_in_ino) {
			/* We're looking at the jffs2_inode_cache, which is
			   at the end of the linked list. Stash it and continue
			   from the beginning of the list */
			ic = (struct jffs2_inode_cache *)(*prev);
			prev = &ic->nodes;
			continue;
		}

		if (SECTOR_ADDR((*prev)->flash_offset) == jeb->offset) {
			/* It's in the block we're erasing */
			struct jffs2_raw_node_ref *this;

			this = *prev;
			*prev = this->next_in_ino;
			this->next_in_ino = NULL;

			if (this == ref)
				break;

			continue;
		}
		/* Not to be deleted. Skip */
		prev = &((*prev)->next_in_ino);
	}

	/* PARANOIA */
	if (!ic) {
		JFFS2_WARNING("inode_cache/xattr_datum/xattr_ref"
			      " not found in remove_node_refs()!!\n");
		return;
	}

	jffs2_dbg(1, "Removed nodes in range 0x%08x-0x%08x from ino #%u\n",
		  jeb->offset, jeb->offset + c->sector_size, ic->ino);

	D2({
		int i=0;
		struct jffs2_raw_node_ref *this;
		printk(KERN_DEBUG "After remove_node_refs_from_ino_list: \n");

		this = ic->nodes;

		printk(KERN_DEBUG);
		while(this) {
			pr_cont("0x%08x(%d)->",
			       ref_offset(this), ref_flags(this));
			if (++i == 5) {
				printk(KERN_DEBUG);
				i=0;
			}
			this = this->next_in_ino;
		}
		pr_cont("\n");
	});

	switch (ic->class) {
#ifdef CONFIG_JFFS2_FS_XATTR
		case RAWNODE_CLASS_XATTR_DATUM:
			jffs2_release_xattr_datum(c, (struct jffs2_xattr_datum *)ic);
			break;
		case RAWNODE_CLASS_XATTR_REF:
			jffs2_release_xattr_ref(c, (struct jffs2_xattr_ref *)ic);
			break;
#endif
		default:
			if (ic->nodes == (void *)ic && ic->pino_nlink == 0)
				jffs2_del_ino_cache(c, ic);
	}
}

void jffs2_free_jeb_node_refs(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	struct jffs2_raw_node_ref *block, *ref;
	jffs2_dbg(1, "Freeing all node refs for eraseblock offset 0x%08x\n",
		  jeb->offset);

	block = ref = jeb->first_node;

	while (ref) {
		if (ref->flash_offset == REF_LINK_NODE) {
			ref = ref->next_in_ino;
			jffs2_free_refblock(block);
			block = ref;
			continue;
		}
		if (ref->flash_offset != REF_EMPTY_NODE && ref->next_in_ino)
			jffs2_remove_node_refs_from_ino_list(c, ref, jeb);
		/* else it was a non-inode node or already removed, so don't bother */

		ref++;
	}
	jeb->first_node = jeb->last_node = NULL;
}

static int jffs2_block_check_erase(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t *bad_offset)
{
	void *ebuf;
	uint32_t ofs;
	size_t retlen;
	int ret;
	unsigned long *wordebuf;

	ret = mtd_point(c->mtd, jeb->offset, c->sector_size, &retlen,
			&ebuf, NULL);
	if (ret != -EOPNOTSUPP) {
		if (ret) {
			jffs2_dbg(1, "MTD point failed %d\n", ret);
			goto do_flash_read;
		}
		if (retlen < c->sector_size) {
			/* Don't muck about if it won't let us point to the whole erase sector */
			jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
				  retlen);
			mtd_unpoint(c->mtd, jeb->offset, retlen);
			goto do_flash_read;
		}
		wordebuf = ebuf-sizeof(*wordebuf);
		retlen /= sizeof(*wordebuf);
		do {
		   if (*++wordebuf != ~0)
			   break;
		} while(--retlen);
		mtd_unpoint(c->mtd, jeb->offset, c->sector_size);
		if (retlen) {
			pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08tx\n",
				*wordebuf,
				jeb->offset +
				c->sector_size-retlen * sizeof(*wordebuf));
			return -EIO;
		}
		return 0;
	}
 do_flash_read:
	ebuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!ebuf) {
		pr_warn("Failed to allocate page buffer for verifying erase at 0x%08x. Refiling\n",
			jeb->offset);
		return -EAGAIN;
	}

	jffs2_dbg(1, "Verifying erase at 0x%08x\n", jeb->offset);

	for (ofs = jeb->offset; ofs < jeb->offset + c->sector_size; ) {
		uint32_t readlen = min((uint32_t)PAGE_SIZE, jeb->offset + c->sector_size - ofs);
		int i;

		*bad_offset = ofs;

		ret = mtd_read(c->mtd, ofs, readlen, &retlen, ebuf);
		if (ret) {
			pr_warn("Read of newly-erased block at 0x%08x failed: %d. Putting on bad_list\n",
				ofs, ret);
			ret = -EIO;
			goto fail;
		}
		if (retlen != readlen) {
			pr_warn("Short read from newly-erased block at 0x%08x. Wanted %d, got %zd\n",
				ofs, readlen, retlen);
			ret = -EIO;
			goto fail;
		}
		for (i=0; i<readlen; i += sizeof(unsigned long)) {
			/* It's OK. We know it's properly aligned */
			unsigned long *datum = ebuf + i;
			if (*datum + 1) {
				*bad_offset += i;
				pr_warn("Newly-erased block contained word 0x%lx at offset 0x%08x\n",
					*datum, *bad_offset);
				ret = -EIO;
				goto fail;
			}
		}
		ofs += readlen;
		cond_resched();
	}
	ret = 0;
fail:
	kfree(ebuf);
	return ret;
}

static void jffs2_mark_erased_block(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	size_t retlen;
	int ret;
	uint32_t uninitialized_var(bad_offset);

	switch (jffs2_block_check_erase(c, jeb, &bad_offset)) {
	case -EAGAIN:	goto refile;
	case -EIO:	goto filebad;
	}

	/* Write the erase complete marker */
	jffs2_dbg(1, "Writing erased marker to block at 0x%08x\n", jeb->offset);
	bad_offset = jeb->offset;

	/* Cleanmarker in oob area or no cleanmarker at all ? */
	if (jffs2_cleanmarker_oob(c) || c->cleanmarker_size == 0) {

		if (jffs2_cleanmarker_oob(c)) {
			if (jffs2_write_nand_cleanmarker(c, jeb))
				goto filebad;
		}
	} else {

		struct kvec vecs[1];
		struct jffs2_unknown_node marker = {
			.magic =	cpu_to_je16(JFFS2_MAGIC_BITMASK),
			.nodetype =	cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER),
			.totlen =	cpu_to_je32(c->cleanmarker_size)
		};

		jffs2_prealloc_raw_node_refs(c, jeb, 1);

		marker.hdr_crc = cpu_to_je32(crc32(0, &marker, sizeof(struct jffs2_unknown_node)-4));

		vecs[0].iov_base = (unsigned char *) &marker;
		vecs[0].iov_len = sizeof(marker);
		ret = jffs2_flash_direct_writev(c, vecs, 1, jeb->offset, &retlen);

		if (ret || retlen != sizeof(marker)) {
			if (ret)
				pr_warn("Write clean marker to block at 0x%08x failed: %d\n",
				       jeb->offset, ret);
			else
				pr_warn("Short write to newly-erased block at 0x%08x: Wanted %zd, got %zd\n",
				       jeb->offset, sizeof(marker), retlen);

			goto filebad;
		}
	}
	/* Everything else got zeroed before the erase */
	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;

	/* Account for cleanmarker now, if it's in-band */
	if (c->cleanmarker_size && !jffs2_cleanmarker_oob(c))
		jffs2_link_node_ref(c, jeb, jeb->offset | REF_NORMAL, c->cleanmarker_size, NULL);

	list_move_tail(&jeb->list, &c->free_list);
	c->nr_erasing_blocks--;
	c->nr_free_blocks++;

	jffs2_dbg_acct_sanity_check_nolock(c, jeb);
	jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

	spin_unlock(&c->erase_completion_lock);
	mutex_unlock(&c->erase_free_sem);
	wake_up(&c->erase_wait);
	return;

filebad:
	jffs2_erase_failed(c, jeb, bad_offset);
	return;

refile:
	/* Stick it back on the list from whence it came and come back later */
	mutex_lock(&c->erase_free_sem);
	spin_lock(&c->erase_completion_lock);
	jffs2_garbage_collect_trigger(c);
	list_move(&jeb->list, &c->erase_complete_list);
	spin_unlock(&c->erase_completion_lock);
	mutex_unlock(&c->erase_free_sem);
	return;
}