net/e1000: allow to overwrite flash size from device tree ...

When barebox probes the e1000 driver and the flash on the i210 device is
unprogrammed, the driver assumes the flash has a size of only 4 kiB.
This is annoying because to program the flash an image must be written
that is bigger than 4 kiB. So you first have to flash the first sector
to make barebox detect the right size on the next boot. Then reset the
board to be able to write the remaining data.

To work around that limitation, try to read the actual size from the
device tree. (Note however that barebox' pci code currently doesn't use
the device tree and so currently this try always fails without further
patching.)

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

rename file_operations -> cdev_operations ...

Linux also has struct file_operations which are something different.
Rename our file_operations to cdev_operations which better matches
what we have.

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

net/e1000: don't register EERPOM device if the content is invalid ...

If the EEPROM content isn't valid, there is no point in registering the
EEPROM device, as it will reject any read attempt anyway.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: don't check EEPROM signature if populated from iNVM ...

The EEPROM device will contain an invalid signature if it has been
populated from iNVM. Since the iNVM enum type has been removed, the
only way to tell if a signature check makes sense is to look at the
EEPROM valid status.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: EEPROM isn't valid if only iNVM is available ...

There is no point in registering the emulated EEPROM device if only the
iNVM is available with no external flash attached to the i210, as in
practice it's only shadowing the iNVM.

When the EEPROM is populated from iNVM, the signature is not valid, which
causes other parts of the driver to fall over. To fix this just ignore
the EEPROM in that case.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: remove one level of indentation ...

By returning early if the MAC type isn't e1000_igb.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: fix driver probing in the presence of two e1000 devices ...

The .id member of the struct device for the invm device is not
initialized and so implicitly zero. This yields:

	register_device: already registered invm0

for the second i210 during probe.

So use the parent's id to initialize the id for invm, too, as is already
done for the corresponding e1000-nor device.

Fixes: a74b97f009c6 ("e1000: Expose i210's iNVM as a cdev")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: indicate at boot time if flash is in secure mode ...

If the flash is in secure mode it is not possible to modify its
contents. So log that useful information at probe time.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: add missing \n in error message ...

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: implement protect and unprotect for attached flash ...

Some supported flash devices (e.g. SST25VF040) are write protected after
power up. If the device holds a valid firmware image the i210 can handle
that just fine. If however there is no firmware programmed, a procedure
is needed to remove this protection before an image can be flashed.

So implement the needed callbacks to make the commands protect and
unprotect do the right thing.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: expand timeout for flash erasure ...

Erasing the whole flash takes approximately 7s on one of my test
machines. Expand the timeout accordingly.

Note however that it is in general not allowed to hold the flash
semaphore for so long and "firmware might implement a timeout
mechanism and take ownership of the relevant [lock]" after one second.
So a chip erase should better only be done when firmware doesn't make
use of the flash.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: indicate in error messages where the failure occured ...

There used to be four places that all emit the same error message. Even
if in a given context not all four of them can be relevant, there are
always two possible locations where the message can origin from.

So make the output slightly different in all places to ease future
debugging.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: don't access the (simulated) eeprom when it is invalid ...

The shadow RAM that is used to serve read requests from the eeprom
interface isn't valid in all cases. Catch these by returning an error in
the eeprom read function and make eeprom validation dependant on
working access.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: log flash/invm status at probe time ...

Provide some info about flash/eeprom state at boot up

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: provide device for accessing emulated eeprom ...

This device uses e1000_read_eeprom to provide access to the emulated
eeprom on e1000-igb. Only reading is implemented for now.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: fix size of invm device ...

The iNVM storage is 2 Kib containing 64 32bit words (0-63).

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: provide access to iNVM even if a flash is present ...

An i210 (aka e1000_igb) supports two different non-volatile storages for
configuration. There is a built-in one-time programmable storage called
iNVM and an optional external SPI-Flash. If a flash is populated and
contains a valid configuration image the iNVM is not used (if I
understood the documentation correctly). Still the iNVM can be useful if
the flash is not configured. Also the iNVM contains manufacturing
identification information.

So it makes sense to provide the invm device even if a flash is present.

This patch also cleans up some confusion that suggests that invm is a
way to access the (simulated) eeprom structures and drops some unused
enum values.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: reorder functions ...

Bring functions in a more natural order which allows to drop a few
forward declarations.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

net/e1000: fix coding style at a few locations ...

While working on the e1000 driver I noticed a few coding style misdeeds.
These are fixed here.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Don't poll for FLSWCTL.GLDONE before starting a flash transaction ...

While FLSWCTL.GLDONE is set when the last transaction was fully
completed, there is no good reason to depend on this. According to the
i210 datasheet having FLSWCTL.DONE is enough.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: implement support for smaller flash chips ...

Even though the register description of the FLA register suggests (on
page 386 of the i210 datasheet (rev. 3.1)) that 2 MB, 4 MB and 8 MB are
the only supported flash sizes, the list of supported flashes (on page
794 of the same document) lists for example a Micron M25PE80 which only
has a size of 1 MB.

Also in general it seems sensible to stick to the formula given for the
meaning of the values that are not explicitly listed.

Acked-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Expose i210's external flash as MTD ...

Add code needed to access SPI-NOR flash attached to i210 as a regular
MTD device.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Expose i210's iNVM as a cdev ...

Add code needed to expose iNVM memory on the chip as a cdev. The
driver also registers a dummy "invm" device that exposes "locked"
property which is used to implement iNMV line locking feature.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Add EEPROM access locking for i210 ...

As per datasheet (section 4.6 p. 147) accessing EEPROM on i210
requires software to hold a corresponding lock bit in SW_FW_SYNC
register.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Refactor Flash/EEPROM reading code ...

Refactor Flash/EEPROM reading code to use vtable with pointers to
small, specialized functions based on the flash class instead of big
monolithic funtions whose behaviour is driven by a number of flags and
variables.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Remove unnecessary intialization ...

We always call e1000_init_eeprom_params() as a part of probing, so
there's no need check if it needs to be called in e1000_read_eeprom().

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Fix a bug in e1000_probe() ...

There are several reasons why that code in e1000_probe had to be
changed:

 - It reads from chip variant specific register (present only on
   i210) in a chip variant agnostic codepath

 - It makes no sense to check for FLUPD bit to make a decision weither
   to validate EEPROM or not since its function per datasheet is:

   " ... Flash Update.

     Writing 1b to this bit causes the content of the internal 4 KB
     shadow RAM to be written into one of the first two 4 KB sectors
     of the Flash device (Sector 0 or Sector 1). The bit is
     self-cleared immediately... "

   and it is only through sheer serendipity the defined value for
   bitmask for FLUPD is equivalent to bitmask for FLASH_DETECTED bit
   which is the bit we actually care about and need to test against
   (FLUPD for i210 has a different bitmask)

Fix those problems by replacing the i210 specific check inside of
e1000_validate_eeprom_checksum() with a chip agnostic one and using
correct bitmask.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Consolidate Microwire EEPROM init code ...

All of the chips that bitbang Microwire to access EEPROM appear to be
configured in the same way, so move common code into a separate
function and make use of it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Consolidate SPI EEPROM init code ...

All of the chips that bitbang SPI to access EEPROM appear to be
configured in the same way, so move common code into a separate
function and make use of it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

e1000: Simplify EEPROM init for e1000_igb ...

That chip specifies read access uising EERD via use_eerd, which means
that none of the more "advanced" EEPROM parameters will be used for
reads, so remove them.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>