state: Allow to load without authentification ...

Sometimes it's useful to be able to load a state even when it
can't be authentificated. Add an option for this.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend bucket circular: Explain metadata ...

Explain why we have metadata and where it is used.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_circular: Set minumum writesize to 8 ...

NOR flashes have a write size of 1. With this the metadata may
end up on non-4-byte-aligned offsets. Force the minimum writesize
to 8 so that the metadata is always at aligned offsets.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_raw: alloc digest only when needed ...

Instead of deferring probe just allocate the digest when
it's needed. This way the credentials can be added later,
possibly on the commandline.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_storage: rename more variables ...

Use "buckets" rather than "copies" in variable names.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_storage: make locally used variable static ...

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_storage: rewrite function doc ...

The function documentation for state_storage_file_buckets_init() is not
very accurate. Rewrite it.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_storage: Rename variable desired_copies to desired_buckets ...

We defined what a bucket is, so rename the variable that holds the
number of desired buckets from desired_copies to desired_buckets.

While at it, make locally used variable static.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_storage: Rename variable nr_copies to n_buckets ...

We defined what a bucket is, so use n_buckets when counting buckets,
and not nr_copies.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_circular: rewrite function doc ...

The commment talks about copies where buckets are meant and also
claims we start at offset 0, which may not be true. Rewrite comment.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_circular: default to circular storage ...

Default to the new circular storage format which saves erase
cycles. The old format can still be selected with
backend-storage-type = "noncircular".

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend: Add some documentation ...

Write some sentences to make the concepts clearer.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: storage: direct: do not close file that is not opened ...

When open failed to not try to close the invalid fd afterwards.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_circular: remove unnecessary warning ...

It's expected that NAND flashes contain bad blocks, do not warn
about them.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend: Add more fields to struct state_backend_storage ...

To save a few function arguments.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_bucket_direct: max_size is always given ...

max_size is always != 0, so if(direct->max_size) can be skipped.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: bucket: Make output more informative ...

Print offset and number of the bucket along with the bucket
specific messages to give a hint which bucket a message is for.

Also it's pretty much expected that buckets sometimes have no
data or need cleanup, so instead of complaining loudly, only
write which bucket is used and which buckets are cleaned up.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend-direct: Fix max_size ...

The max_size in the direct backend includes the meta data, so
substract its size when determing the max data size we can store.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: Drop cache bucket ...

The cache bucket sits between the storage functions and the backend
storage. We only read from the storage once, so there is no need to cache
anything. The real purpose of the cache bucket is to keep the -EUCLEAN
information when a NAND block needs to be rewritten and to keep the read
buffers as long as the backend iterates over all buckets trying to find
the one we want to use.

This can be coded easier and more obvious in the backend code, so drop
the cache bucket.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: Convert all bufs to void * ...

A void * is a much better type for a buffer than a u8 * as it
can be casted to any other type implicitly. Convert all buffers
used by the state framework to void *.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: replace len_hint logic ...

The len_hint mechanism is rather hard to understand as it's not clear
from where to where the hint is passed and also it's not clear what
happens if the hint is empty or wrong.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: simplify direct backend ...

- drop support for regular files. This, if at all, is only useful for
  debugging. For the debugging case still a file of sufficient size
  can be created manually.
- make stridesize mandatory. Makes the code simpler.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: drop lazy_init ...

lazy_init is an optimization that makes it possible to read only up to
the first valid bucket when starting. However, when restoring consistency,
immediately afterwards we have we have to initialize all buckets anyway,
so being lazy doesn't give us any gain. Remove it to simplify the code.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: backend_circular: Read whole PEB ...

When the circular backend searches for the last page written in the
eraseblock, it iterates backwards pagewise from the end of the block.
This is ok for NAND flash, but on NOR flash, which does not have pages,
the code ends up iterating bytewise backwards, calling into mtd each
time. This is very time consuming, so optimize this by reading the whole
eraseblock once and just iterate over the buffer in memory.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: storage: initialize variable once outside loop ...

writesize is initialized with the same value in each loop iteration,
Instead, initialize it once outside the loop.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: pass struct state * to storage functions ...

We can get a state_backend_storage * and the device * from struct state,
so pass this to the storage functions rather than the two pointers.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: remove unnecessary argument from state_format_init ...

The device pointer is already in struct state, no need to pass it
around when a struct state * is already passed.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: open code state_backend_init in caller ...

Safes a lot of argument passing to a function that is used
only once.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: merge backend.c into state.c ...

The code in backend.c is too small to justify an extra file. Merge it
into state.c.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

state: Drop backend as extra struct type ...

struct state_backend is embedded into struct state. This additional
indirection does not have any real gain. Drop it.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>