linux-toradex.git/drivers/mtd/mtdpart.c, branch v3.4.2

mtd: flash drivers set ecc strength

2012-03-26T23:56:46+00:00

Flash device drivers initialize 'ecc_strength' in struct mtd_info, which is the
maximum number of bit errors that can be corrected in one writesize region.

Drivers using the nand interface intitialize 'strength' in struct nand_ecc_ctrl,
which is the maximum number of bit errors that can be corrected in one ecc step.
Nand infrastructure code translates this to 'ecc_strength'.

Also for nand drivers, the nand infrastructure code sets ecc.strength for ecc
modes NAND_ECC_SOFT, NAND_ECC_SOFT_BCH, and NAND_ECC_NONE.  It is set in the
driver for all other modes.

Signed-off-by: Mike Dunn 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: fix partition wrapper functions

2012-03-26T23:44:29+00:00

This patch reverts a change that may have been mistakenly included with the set
of patches that introduced the new mtd api entry functions.  Or perhaps I am
mistaken :)

The problem is in the partition wrapper functions, where the calls to the driver
methods were replaced with calls to the new mtd api functions.  This causes the
api function to be called a second time, further down the call stack.  This is
not only unnecessary and redundant - because the sanity checking code and (more
restrictive) bounds checks for the partition were done in the first call - but
is potentially problematic and confusing.

For example, the call stack for a call to mtd_read() on a partitioned device
currently looks like this:

mtd_read()             gets struct mtd_info for the partition
|
+-> part_read()        via the pointer assigned when the partition was created
    |
    +->mtd_read()      this time gets struct mtd_info for the master
       |
       +->xyz_driver_read()  via the pointer asigned by the driver

It seems that this can cause a variety of problems.  For example, if you want to
add code to the api function that tests a value in mtd_info that is relevant
only to the partition.  Or (in my case) you want the driver to return a value
that may be different from that returned by the mtd api function.

This patch eliminates the second call to the mtd api function.  It was tested on
the docg4 nand driver with a subset of the api functions, but I inspected the
rest and don't see any problems.

Signed-off-by: Mike Dunn 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: remove R/O checking duplication

2012-03-26T23:29:11+00:00

Many drivers check whether the partition is R/O and return -EROFS if yes.
Let's stop having duplicated checks and move them to the API functions
instead.

And again a bit of noise - deleted few too sparse newlines, sorry.

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: do not duplicate length and offset checks in drivers

2012-03-26T23:28:18+00:00

We already verify that offset and length are within the MTD device size
in the MTD API functions. Let's remove the duplicated checks in drivers.
This patch only affects the following API's:

'mtd_erase()'
'mtd_point()'
'mtd_unpoint()'
'mtd_get_unmapped_area()'
'mtd_read()'
'mtd_write()'
'mtd_panic_write()'
'mtd_lock()'
'mtd_unlock()'
'mtd_is_locked()'
'mtd_block_isbad()'
'mtd_block_markbad()'

This patch adds a bit of noise by removing too sparse empty lines, but this is
not too bad.

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: return error code from mtd_unpoint

2012-03-26T23:27:19+00:00

The 'mtd_unpoint()' API function should be able to return an error code because
it may fail if you specify incorrect offset. This patch changes this MTD API
function and amends all the drivers correspondingly.

Also return '-EOPNOTSUPP' from 'mtd_unpoint()' when the '->unpoint()' method is
undefined. We do not really need this currently, but this just makes
sense to be consistent with 'mtd_point()'.

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: add leading underscore to all mtd functions

2012-03-26T23:20:01+00:00

This patch renames all MTD functions by adding a "_" prefix:

mtd->erase -> mtd->_erase
mtd->read_oob -> mtd->_read_oob
...

The reason is that we are re-working the MTD API and from now on it is
an error to use MTD function pointers directly - we have a corresponding
API call for every pointer. By adding a leading "_" we achieve the following:

1. Make sure we convert every direct pointer users
2. A leading "_" suggests that this interface is internal and it becomes
   less likely that people will use them directly
3. Make sure all the out-of-tree modules stop compiling and the owners
   spot the big API change and amend them.

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: minor coding style cleanup in mtdpart.c

2012-03-26T23:16:24+00:00

Signed-off-by: Stefan Roese 
Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: introduce mtd_block_markbad interface

2012-01-09T18:25:48+00:00

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: introduce mtd_block_isbad interface

2012-01-09T18:25:47+00:00

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse

mtd: introduce mtd_resume interface

2012-01-09T18:25:46+00:00

Signed-off-by: Artem Bityutskiy 
Signed-off-by: David Woodhouse