As the first step towards eliminating the ref->next_phys member and saving
memory by using an _array_ of struct jffs2_raw_node_ref per eraseblock,
stop the write functions from allocating their own refs; have them just
_reserve_ the appropriate number instead. Then jffs2_link_node_ref() can
just fill them in.

Use a linked list of pre-allocated refs in the superblock, for now. Once
we switch to an array, it'll just be a case of extending that array.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

First step of modularizing ECC support.
- Move ECC related functionality into a seperate embedded data structure
- Get rid of the hardware dependend constants to simplify new ECC models
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Seperate functionality out of nand_scan so the code is more
readable. No functional change. First step of simplifying
the nand driver.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The NAND driver used a mix of unsigned char, u_char amd uint8_t
data types. Consolidate to uint8_t usage
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

The writev based write buffer implementation was far to complex as
in most use cases the write buffer had to be handled anyway.
Simplify the write buffer handling and use mtd->write instead.

From extensive testing no performance impact has been noted.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

NDFC NAND Flash controller is embedded in PPC EP44x SoCs.
Add platform driver based support.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Add the data structures necessary to provide platform device support
for NAND
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Replace the chip lock by a the controller lock. For simple drivers a
dummy controller structure is created by the scan code.
This simplifies the locking algorithm in nand_get/release_chip().
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Unrolling the loops produces denser and much faster code.
Add a config switch which allows to select the byte order of the
resulting ecc code. The current Linux implementation has a byte
swap versus the SmartMedia specification
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

We don't need the upper layers to deal with the physical offset. It's
_always_ c->nextblock->offset + c->sector_size - c->nextblock->free_size
so we might as well just let the actual write functions deal with that.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

o Add a flag MTD_BIT_WRITEABLE for devices that allow single bits to be
  cleared.
o Replace MTD_PROGRAM_REGIONS with a cleared MTD_BIT_WRITEABLE flag for
  STMicro and Intel Sibley flashes with internal ECC.  Those flashes
  disallow clearing of single bits, unlike regular NOR flashes, so the
  new flag models their behaviour better.
o Remove MTD_ECC.  After the STMicro/Sibley merge, this flag is only set
  and never checked.
Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>

In 2002, STMicro started producing NOR flashes with internal ECC protection
for small blocks (8 or 16 bytes).  Support for those flashes was added by me.
In 2005, Intel Sibley flashes copied this strategy and Nico added support for
those.  Merge the code for both.
Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>

At least two flashes exists that have the concept of a minimum write unit,
similar to NAND pages, but no other NAND characteristics.  Therefore, rename
the minimum write unit to "writesize" for all flashes, including NAND.
Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>

Two flags exist to decide whether a device is writeable or not.  None of
those two flags is checked for independently, so they are clearly redundant,
if not an invitation to bugs.  This patch removed both of them, replacing
them with a single new flag.
Signed-off-by: Joern Engel <joern@wh.fh-wedel.de>

We'll be using a proper list of nodes in the jffs2_xattr_datum and
jffs2_xattr_ref structures, because the existing code to overwrite
them is just broken. Put it in the common part at the front of the
structure which is shared with the jffs2_inode_cache, so that the
jffs2_link_node_ref() function can do the right thing.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

In a couple of places, we assume that what's at the end of the
->next_in_ino list is a struct jffs2_inode_cache. Let's check
for that, since we expect it to change soon.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Let's avoid the potential for forgetting to set ref->next_in_ino, by doing
it within jffs2_link_node_ref() instead.

This highlights the ugliness of what we're currently doing with
xattr_datum and xattr_ref structures -- we should find a nicer way of
dealing with that.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

When filing REF_OBSOLETE nodes, we'd add their size to the global
'dirty_size' count, but then to the eraseblock's 'used_size' count.
That's not clever.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

I added an argument to the real function...
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>

The previous code wouldn't work correctly on architectures which have a
non-empty MODULE_SYMBOL_PREFIX, and this version is neater if slightly
less optimal in the built-in case.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

The patch below adds support for the NAND device on the Amstrad Delta.
This is a 32MiB 8bit Toshiba device, with the data bus connected to the
OMAP MPUIO pins and ALE, CLE, NCE, NRE, NWE and NWP all connected to the
Delta's latch2 16bit latch.
Signed-Off-By: Jonathan McDowell <noodles@earth.li>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Well, almost. We'll actually keep a 'TEST_TOTLEN' macro set for now, and keep
doing some paranoia checks to make sure it's all working correctly. But if
TEST_TOTLEN is unset, the size of struct jffs2_raw_node_ref drops from 16
bytes to 12 on 32-bit machines. That's a saving of about half a megabyte of
memory on the OLPC prototype board, with 125K or so nodes in its 512MiB of
flash.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

We can't use jffs2_scan_dirty_space() because it doesn't do any locking; it's
only for use at scan time -- hence the 'scan' in the name.

Also, don't allocate refs while we have c->erase_completion_lock held.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

We don't allocate this locally any more -- it's given to us and owner by
our caller. Also improve the debug messages a little.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Next step in ongoing campaign to file a struct jffs2_raw_node_ref for every
piece of dirty space in the system, so that __totlen can be killed off....
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

If __totlen is going away, we need to pass the length in separately.
Also stop callers from needlessly setting ref->next_phys to NULL,
since that's done for them... and since that'll also be going away soon.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Make sure we allocate a ref for any dirty space which exists between nodes
which we find in an eraseblock summary.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

The incoming ref_totlen() calculation is going to rely on the existence
of nodes which cover all dirty space. We can't just tweak the accounting
data any more; we have to call jffs2_scan_dirty_space() to do it.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

To eliminate the __totlen field from struct jffs2_raw_node_ref, we need
to allocate nodes for dirty space instead of just tweaking the accounting
data. Introduce jffs2_scan_dirty_space() in preparation for that.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

For RWCOMPAT and ROCOMPAT nodes, we should still allow the mount to
succeed. Just abandon the summary and fall through to the full scan.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

If we had to allocate extra space for the summary node, we weren't
correctly freeing it when jffs2_sum_scan_sumnode() returned nonzero --
which is both the success and the failure case. Only when it returned
zero, which means fall through to the full scan, were we correctly freeing
the buffer.

Document the meaning of those return codes while we're at it.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

We should preserve these when we come to garbage collect them, not let
them get erased. Use jffs2_garbage_collect_pristine() for this, and make
sure the summary code copes -- just refrain from writing a summary for any
block which contains a node we don't understand.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

It should all be counted as dirty space, not wasted and _definitely_ not
unchecked.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

The same sequence of code was repeated in many places, to add a new
struct jffs2_raw_node_ref to an eraseblock and adjust the space accounting
accordingly. Move it out-of-line.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

Signed-off-by: David Woodhouse <dwmw2@infradead.org>