commands/*: Replace license and copyright boilerplate by SPDX identfiers ...

While at it also drop references to the non-existing CREDITS file and do
some small rearrangements for some uniform formatting.
(SPDX-License-Identifier first, then copyright texts and then an empty
line.)

The advantage is that these specifiers are machine-parseable which helps
license conformance.

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

devfs: Drop dev_lseek_default() ...

Only the following cdevs do not declare an .lseek() operation:

  - Console devices in common/console.c
  - Firmware framework in common/firmware.c
  - JTAG driver in drivers/misc/jtag.c
  - UBI in drivers/mtd/ubi/barebox.c

Of those four, first two are marked DEVFS_IS_CHARACTER_DEV and
implement only .write() operation and the last two don't implement
anything but .ioctl(). While there's probably no meaningful way to use
lseek() against any of those devices, there doesn't seem to be any
harm in allowing it either.

Change devfs_lseek() to ignore absense of .lseek() callback and drop
dev_lseek_default() and all references to it in the codebase.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
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>

fs: add prng device ...

this should provide easy access to get_random_bytes() interfaces.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

treewide: remove address of the Free Software Foundation ...

The FSF address has changed; The FSF site says that
address is

  Free Software Foundation
  51 Franklin Street, Fifth Floor
  Boston, MA 02110-1301
  USA

(see http://www.fsf.org/about/contact/)

Instead of updating it each time the address changes,
just drop it completely treewide.

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

fs: fix standard zero, full devices ...

The standard devices are currently broken since they have
the size ~0. As now files use loff_t as file size which is a signed
type the read implementation gets confused and now returns -1.

The current implementation also has the (somewhat theorical) problem
that we do not have real streaming devices, so /dev/zero went out
of zeroes after reading 4GB (or now LLONG_MAX).

This patch introduces a new cdev flag DEVFS_IS_CHARACTER_DEV and a new
file size flag FILE_SIZE_STREAM which makes it possible to create
real stream devices instead.

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

Merge branch 'for-next/devnull' ...

Conflicts:
	commands/mem.c

Added "/dev/full" and "/dev/null" devices ...

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

Move /dev/zero to separate unit ...

This patch allows to present "/dev/zero" always in system and not
depending  of mem-command. Standard files allow to test other memory
devices, not only "mem", such as NOR, NAND, MCI-devices e.t.c.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>