treewide: make use of PTR_ERR_OR_ZERO ...

PTR_ERR_OR_ZERO is designed to replace boiler plate like:

	if (IS_ERR(x))
		return PTR_ERR(x);
	return 0;

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

globalvar: Allow NULL pointers to be returned by dev_add_param() ...

The following commit will change the return value of dev_add_param()
from -ENOSYS to NULL if CONFIG_PARAMETER is disabled. After that,
building without CONFIG_PARAMETER will return a NULL pointer to
__nvvar_add() instead of an error.

Signed-off-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Allow usage of default environment without environment file storage ...

Currently, the default environment is only used when the
barebox environment on the persistent store is not valid
or when ENVFS_FLAGS_FORCE_BUILT_IN is set in the super block.

However, ENVFS_FLAGS_FORCE_BUILT_IN can be cleared and the
environmnet variables in the persistent store will be
used again. This may not be desirable.

This patch allows building CONFIG_DEFAULT_ENVIRONMENT
independent of CONFIG_ENV_HANDLING. This can be useful
if you never want to load or write values from the
persistent store and you only need to read environment variables
from your default environment.

If CONFIG_ENV_HANDLING is not set, a message will be printed to the
user indicating that changes to non-volatile variables won't be
persisted.

Move envfs functions that are needed when CONFIG_DEFAULT_ENVIRONMENT
and/or CONFIG_ENV_HANDLING is set to a new file common/envfs-core.c.

Signed-off-by: Albert Schwarzkopf <a.schwarzkopf@phytec.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

globalvar: fix crash if CONFIG_NVVAR is not set ...

At the moment globalvar code tries to use nv_device
even if nv_device is not registered.

How to reproduce the problem:

    barebox$ make sandbox_defconfig
    ...
    barebox$ sed -i "s/\(CONFIG_NVVAR\)=y/# \1 is not set/" .config
    barebox$ sed -i "s/\(CONFIG_DEFAULT_ENVIRONMENT_GENERIC_NEW\)=y/# \1 is not set\n# CONFIG_DEFAULT_ENVIRONMENT_GENERIC is not set/" .config
    barebox$ make oldconfig
    ...
    barebox$ make
    ...
    barebox$ ./barebox
    Segmentation fault

This patch blocks nv_device use if CONFIG_NVVAR is not set.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Merge branch 'for-next/net'

Merge branch 'for-next/misc'

nvvar: when setting a nvvar to NULL just free the content ...

When a nvvar is about to be removed then it is set to NULL
by barebox. This means for the variable to free it's memory.
In this case also do not pass the value to the corresponding
globalvar, since that would set the globalvar to NULL aswell,
but we want to keep its current value.

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

common: globalvar: fix removing multiple nvvars with wildcards ...

nvvar_remove takes wildcards, so it can remove multiple variables. This
means we cannot return after the first loop iteration, but instead must
continue.

Fixes: 609d3edc3ad9 (common: globvar: let nvvar_remove() report non-existing variable)

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

nvvar: Initialze from underlying device parameter ...

When a nvvar is added with a NULL parameter then it's initialized
with the value of the underlying global variable. Do this aswell
when the nvvar is a device parameter.

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

nv: add device parameter overwrites to completion list ...

nv variables in the form dev.<devname>.* can be used to make device
parameters persistent. Add these to the completion list to make setting
these variables more convenient.

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

globalvar: When a globalvar is created with a NULL value, use empty string ...

As a convenience for users of globalvar_add_simple_string() create an
empty value for the variable when passed a NULL pointer as value.

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

common: globvar: let nvvar_remove() report non-existing variable ...

The former implementation did not allow to detect whether the call to
nvvar_remove() succeeded or failed and always returned 0.

This changes the implementation to return 0 only if a variable with the
given name was found and return ENOENT otherwise.

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

Revert "nv: Do not create globalvars from nvvars" ...

This reverts commit 35d8e85.

Revert "globalvar: remove code for unqualified globalvars" ...

This reverts commit e4f8105.

Revert "globalvar: make globalvar functions more consistent" ...

This reverts commit 1b4a05c.

Revert "param: remove unnecessary device_d * argument" ...

This reverts commit 0071bac.

Revert "globalvar: don't use nv_device if CONFIG_NVVAR is disabled" ...

This reverts commit b378e8c.

Revert "globalvar: make nv_device static" ...

This reverts commit f655902.

Revert "nv: Fix setting of nv.dev.<devname>.<param> variables" ...

This reverts commit eaf884b.

Revert "globalvar: Fix value of new globalvar when nvvar exists" ...

This reverts commit f8a1774.

globalvar: Fix value of new globalvar when nvvar exists ...

When a new globalvar with a value is created and the corresponding
nvvar exists, then the globalvar gets the value of the nvvar, not
from the newly assigned value as expected.

nv quux=foo; global quux=bar; echo ${global.quux}

Should give "bar", not "foo". Fix this.

Reported-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

nv: Fix setting of nv.dev.<devname>.<param> variables ...

nv variables with the form nv.dev.<devname>.<param> shall be mirrored to
the device parameter <param> of the device named <devname>. This is
broken since:

| commit 35d8e85
| Author: Sascha Hauer <s.hauer@pengutronix.de>
| Date:   Thu Apr 6 15:23:56 2017 +0200
|
|     nv: Do not create globalvars from nvvars

Fix this by attaching the setting of the mirror device parameter
directly to the nv device rather than to the global device.

Reported-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Merge branch 'for-next/parameter-types'

Merge branch 'for-next/misc'

globalvar: make nv_device static ...

nv_device isn't used outside of common/globalvar.c
so make it static.

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

globalvar: don't use nv_device if CONFIG_NVVAR is disabled ...

At the moment barebox crashes if CONFIG_NVVAR is disabled
because of access to unregistered nv_device in
get_param_by_name(&nv_device, "version").

How to reproduce the crash:

    barebox$ unset ARCH
    barebox$ unset CROSS_COMPILE
    barebox$ make sandbox_defconfig
    barebox$ sed -i "s/CONFIG_ENV_HANDLING=y/# CONFIG_ENV_HANDLING is not set/" .config
    barebox$ make oldconfig
    barebox$ ./barebox
    Segmentation fault

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

param: remove unnecessary device_d * argument ...

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

globalvar: make globalvar functions more consistent ...

Similar to the device parameter functions also make the globalvar
functions more consistent. This also adds support for readonly
globalvars and changes several existing globalvars which should
really be readonly to readonly.

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

Merge branch 'for-next/misc'

globalvar: remove code for unqualified globalvars ...

The globalvar_add_simple_* functions will fail when a globalvar of
the name already exists. This happened when the globalvar was created
previously because a corresponding nvvar existed. For this reason we
removed the globalvars that have been previously created by nvvar
creation (we called these unqualified globalvars). Since we no longer
create the corresponding globalvars on nvvar creation this code is
no longer needed. Remove it.

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