staging: vc04_services: Re-add dependency on HAS_DMA to BCM2835_VCHIQ

Thanks to stubs for the NO_DMA=y case, drivers that use the DMA API can
be compile-tested on systems that do not support DMA. Hence the
dependency of BCM2835_VCHIQ on HAS_DMA was dropped to increase compile
coverage.

Unfortunately compilers became smarter, leading to new failures.
E.g. for a CONFIG_SUN3=y allmodconfig kernel with gcc 9.4.0:

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c: In function ‘free_pagelist’:
arch/m68k/include/asm/string.h:72:25: warning: argument 2 null where non-null expected [-Wnonnull]
72 | #define memcpy(d, s, n) __builtin_memcpy(d, s, n)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:614:4: note: in expansion of macro ‘memcpy’
614 | memcpy((char *)kmap(pages[0]) +
| ^~~~~~
arch/m68k/include/asm/string.h:72:25: note: in a call to built-in function ‘__builtin_memcpy’
72 | #define memcpy(d, s, n) __builtin_memcpy(d, s, n)
| ^~~~~~~~~~~~~~~~~~~~~~~~~
drivers/staging/vc04_services/interface/vchiq_arm/vchiq_2835_arm.c:614:4: note: in expansion of macro ‘memcpy’
614 | memcpy((char *)kmap(pages[0]) +
| ^~~~~~

This happens because the compiler can trace back the source pointer to a
allocation by dma_alloc_attrs(), which always returns NULL if NO_DMA=y.

Avoid this reinstating the dependency of the BCM2835_VCHIQ symbol on
HAS_DMA, and by restricting the selection of BCM2835_VCHIQ.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/r/da55bd87eebf1a969dc8ccd807843319833f6c40.1650888813.git.geert@linux-m68k.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

media: Kconfig: cleanup VIDEO_DEV dependencies

media Kconfig has two entries associated to V4L API:
VIDEO_DEV and VIDEO_V4L2.

On Kernel 2.6.x, there were two V4L APIs, each one with its own flag.
VIDEO_DEV were meant to:
1) enable Video4Linux and make its Kconfig options to appear;
2) it makes the Kernel build the V4L core.

while VIDEO_V4L2 where used to distinguish between drivers that
implement the newer API and drivers that implemented the former one.

With time, such meaning changed, specially after the removal of
all V4L version 1 drivers.

At the current implementation, VIDEO_DEV only does (1): it enables
the media options related to V4L, that now has:

menu "Video4Linux options"
visible if VIDEO_DEV

source "drivers/media/v4l2-core/Kconfig"
endmenu

but it doesn't affect anymore the V4L core drivers.

The rationale is that the V4L2 core has a "soft" dependency
at the I2C bus, and now requires to select a number of other
Kconfig options:

config VIDEO_V4L2
tristate
depends on (I2C || I2C=n) && VIDEO_DEV
select RATIONAL
select VIDEOBUF2_V4L2 if VIDEOBUF2_CORE
default (I2C || I2C=n) && VIDEO_DEV

In the past, merging them would be tricky, but it seems that it is now
possible to merge those symbols, in order to simplify V4L dependencies.

Let's keep VIDEO_DEV, as this one is used on some make *defconfig
configurations.

Suggested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Neil Armstrong <narmstrong@baylibre.com> # for meson-vdec & meson-ge2d
Acked-by: Andrzej Pietrasiewicz <andrzejtp2010@gmail.com>
Acked-by: Łukasz Stelmach <l.stelmach@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

staging: bcm2835: Break MMAL support out from camera

The BCM2835 camera host is currently the only component that uses the
VCHIQ MMAL interface. This will soon change with the upporting of
BCM2835 ISP, which make use of the same interface.

Break VCHIQ MMAL interface support out from camera host directory to
make it possible for the ISP driver to use it as well.

The only modification to the existing mmal code is the introduction of
EXPORT_SYMBOL() for symbols required by bcm2835-camera and the addition
of the module author and licenses.

Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Link: https://lore.kernel.org/r/20200623164235.29566-2-nsaenzjulienne@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: add missing SPDX lines to Kconfig files

There are a few remaining drivers/staging/*/Kconfig files that do not
have SPDX identifiers in them. Add the correct GPL-2.0 identifier to
them to make scanning tools happy.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: bcm2835-camera: remove depends on ARM

Since all the arm64 specific issues have been fixed now
and the camera is working fine with a arm64 kernel, the
depends on ARM can be removed from Kconfig.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: bcm2835_camera: Use a mapping table for context field of mmal_msg_header

The camera driver passes messages back and forth between the firmware with
requests and replies. One of the fields of the message header called
context is a pointer so the size changes between 32 bit and 64 bit.

The context field is used to pair reply messages from the firmware with
request messages from the kernel. The simple solution would be
to use the padding field for the upper 32 bits of pointers, but this
would rely on the firmware always copying the pad field.

So instead handles are generated that are 32 bit numbers and a mapping
stored in a btree as implemented by the btree library in the kernel lib
directory. The mapping pairs the handle with the pointer to the actual
data. The btree library was chosen since it's very easy to use and
red black trees would be overkill.

The camera driver also now forces in the btree library if the camera is
included in the build. The btree library is a hidden configuration
option.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: bcm2835-camera: select BCM2835_VCHIQ rather then depending on it.

Change the camera's dependency on BCM2835_VCHIQ to a select
since camera support is typically more important to people
then base VCHIQ(which they may not even know what it's for).

Also, with a dependency the camera support would not be
visiable until VCHIQ is selected first, and that may
not be what most people would expect.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: bcm2835-camera: Update driver name

Update the name of the camera driver as displayed
by the Kconfig to match the audio driver style.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

staging: bcm2835-camera: Move driver under vc04_services

The bcm2835-camera driver is part of v04_services, so it makes
sense for it to be located under vc04_services to make
configuration clearer.

Signed-off-by: Michael Zoran <mzoran@crowfest.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>