drm/client: Do not acquire module reference

Do not acquire a reference on the module that provides a client's
callback functions in drm_client_init(). The additional reference
prevents the user from unloading the callback functions' module and
thus creating dangling pointers.

This is only necessary if there is no direct dependency between the
caller of drm_client_init() and the provider of the callbacks in
struct drm_client_funcs. If this case ever existed, it has been
removed from the DRM code. Callers of drm_client_init() also provide
the callback implementation. The lifetime of the clients is tied to
the dependency chain's outer-most module, which is the hardware's
DRM driver. Before client helpers could be unloaded, the driver module
would have to be unloaded, which also unregisters all clients.

Driver modules that set up DRM clients can now be unloaded.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231102131056.7256-2-tzimmermann@suse.de

drm/client: Convert drm_client_buffer_addfb() to drm_mode_addfb2()

Currently drm_client_buffer_addfb() uses the legacy drm_mode_addfb(),
which uses bpp and depth to guess the wanted buffer format.
However, drm_client_buffer_addfb() already knows the exact buffer
format, so there is no need to convert back and forth between buffer
format and bpp/depth, and the function can just call drm_mode_addfb2()
directly instead.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/4b84adfc686288714e69d0442d22f1259ff74903.1697379891.git.geert@linux-m68k.org

drm/debugfs: rework debugfs directory creation v5

Instead of the per minor directories only create a single debugfs
directory for the whole device directly when the device is initialized.

For DRM devices each minor gets a symlink to the per device directory
for now until we can be sure that this isn't useful any more in any way.

Accel devices create only the per device directory and also drops the mid
layer callback to create driver specific files.

v2: cleanup accel component as well
v3: fix typo when debugfs is disabled
v4: call drm_debugfs_dev_fini() during release as well,
some kerneldoc typos fixed
v5: rebased and one more kerneldoc fix

Signed-off-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230829110115.3442-4-christian.koenig@amd.com
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>

drm/client: Send hotplug event after registering a client

Generate a hotplug event after registering a client to allow the
client to configure its display. Remove the hotplug calls from the
existing clients for fbdev emulation. This change fixes a concurrency
bug between registering a client and receiving events from the DRM
core. The bug is present in the fbdev emulation of all drivers.

The fbdev emulation currently generates a hotplug event before
registering the client to the device. For each new output, the DRM
core sends an additional hotplug event to each registered client.

If the DRM core detects first output between sending the artificial
hotplug and registering the device, the output's hotplug event gets
lost. If this is the first output, the fbdev console display remains
dark. This has been observed with amdgpu and fbdev-generic.

Fix this by adding hotplug generation directly to the client's
register helper drm_client_register(). Registering the client and
receiving events are serialized by struct drm_device.clientlist_mutex.
So an output is either configured by the initial hotplug event, or
the client has already been registered.

The bug was originally added in commit 6e3f17ee73f7 ("drm/fb-helper:
generic: Call drm_client_add() after setup is done"), in which adding
a client and receiving a hotplug event switched order. It was hidden,
as most hardware and drivers have at least on static output configured.
Other drivers didn't use the internal DRM client or still had struct
drm_mode_config_funcs.output_poll_changed set. That callback handled
hotplug events as well. After not setting the callback in amdgpu in
commit 0e3172bac3f4 ("drm/amdgpu: Don't set struct
drm_driver.output_poll_changed"), amdgpu did not show a framebuffer
console if output events got lost. The bug got copy-pasted from
fbdev-generic into the other fbdev emulation.

Reported-by: Moritz Duge <MoritzDuge@kolahilft.de>
Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/2649
Fixes: 6e3f17ee73f7 ("drm/fb-helper: generic: Call drm_client_add() after setup is done")
Fixes: 8ab59da26bc0 ("drm/fb-helper: Move generic fbdev emulation into separate source file")
Fixes: b79fe9abd58b ("drm/fbdev-dma: Implement fbdev emulation for GEM DMA helpers")
Fixes: 63c381552f69 ("drm/armada: Implement fbdev emulation as in-kernel client")
Fixes: 49953b70e7d3 ("drm/exynos: Implement fbdev emulation as in-kernel client")
Fixes: 8f1aaccb04b7 ("drm/gma500: Implement client-based fbdev emulation")
Fixes: 940b869c2f2f ("drm/msm: Implement fbdev emulation as in-kernel client")
Fixes: 9e69bcd88e45 ("drm/omapdrm: Implement fbdev emulation as in-kernel client")
Fixes: e317a69fe891 ("drm/radeon: Implement client-based fbdev emulation")
Fixes: 71ec16f45ef8 ("drm/tegra: Implement fbdev emulation as in-kernel client")
Fixes: 0e3172bac3f4 ("drm/amdgpu: Don't set struct drm_driver.output_poll_changed")
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Moritz Duge <MoritzDuge@kolahilft.de>
Tested-by: Torsten Krah <krah.tm@gmail.com>
Tested-by: Paul Schyska <pschyska@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@gmail.com>
Cc: Noralf Trønnes <noralf@tronnes.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Inki Dae <inki.dae@samsung.com>
Cc: Seung-Woo Kim <sw0312.kim@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Patrik Jakobsson <patrik.r.jakobsson@gmail.com>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: "Pan, Xinhui" <Xinhui.Pan@amd.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Mikko Perttunen <mperttunen@nvidia.com>
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: amd-gfx@lists.freedesktop.org
Cc: linux-tegra@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v5.2+
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> # msm
Link: https://patchwork.freedesktop.org/patch/msgid/20230710091029.27503-1-tzimmermann@suse.de

drm/client: Add hotplug_failed flag

Signal failed hotplugging with a flag in struct drm_client_dev. If set,
the client helpers will not further try to set up the fbdev display.

This used to be signalled with a combination of cleared pointers in
struct drm_fb_helper, which prevents us from initializing these pointers
early after allocation.

The change also harmonizes behavior among DRM clients. Additional DRM
clients will now handle failed hotplugging like fbdev does.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230125200415.14123-3-tzimmermann@suse.de

drm/client: Test for connectors before sending hotplug event

Test for connectors in the client code and remove a similar test
from the generic fbdev emulation. Do nothing if the test fails.
Not having connectors indicates a driver bug.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230125200415.14123-2-tzimmermann@suse.de

drm: use new debugfs device-centered functions on DRM core files

Replace the use of drm_debugfs_create_files() with the new
drm_debugfs_add_files() function in all DRM core files, centering the
debugfs files management on the drm_device instead of drm_minor.

Signed-off-by: Maíra Canal <mcanal@igalia.com>
Reviewed-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Melissa Wen <mwen@igalia.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20221219120621.15086-3-mcanal@igalia.com

drm/client: fix circular reference counting issue

We reference dump buffers both by their handle as well as their
object. The problem is now that when anybody iterates over the DRM
framebuffers and exports the underlying GEM objects through DMA-buf
we run into a circular reference count situation.

The result is that the fbdev handling holds the GEM handle preventing
the DMA-buf in the GEM object to be released. This DMA-buf in turn
holds a reference to the driver module which on unload would release
the fbdev.

Break that loop by releasing the handle as soon as the DRM
framebuffer object is created. The DRM framebuffer and the DRM client
buffer structure still hold a reference to the underlying GEM object
preventing its destruction.

Signed-off-by: Christian König <christian.koenig@amd.com>
Fixes: c76f0f7cb546 ("drm: Begin an API for in-kernel clients")
Cc: <stable@vger.kernel.org>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230126102814.8722-1-christian.koenig@amd.com

drm/client: Prevent NULL dereference in drm_client_buffer_delete()

The drm_gem_vunmap() will crash with a NULL dereference if the passed
object pointer is NULL. It wasn't a problem before we added the locking
support to drm_gem_vunmap function because the mapping argument was always
NULL together with the object. Make drm_client_buffer_delete() to check
whether GEM is NULL before trying to unmap the GEM, it will happen on
framebuffer creation error.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://lore.kernel.org/dri-devel/Y1kFEGxT8MVlf32V@kili/
Fixes: 79e2cf2e7a19 ("drm/gem: Take reservation lock for vmap/vunmap operations")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221030154412.8320-3-dmitry.osipenko@collabora.com

drm/client: Switch drm_client_buffer_delete() to unlocked drm_gem_vunmap

The drm_client_buffer_delete() wasn't switched to unlocked GEM vunmapping
by accident when rest of drm_client code transitioned to the unlocked
variants of the vmapping functions. Make drm_client_buffer_delete() use
the unlocked variant. This fixes lockdep warning splat about missing
reservation lock when framebuffer is released.

Reported-by: kernel test robot <yujie.liu@intel.com>
Link: https://lore.kernel.org/dri-devel/890f70db-68b0-8456-ca3c-c5496ef90517@collabora.com/T/
Fixes: 79e2cf2e7a19 ("drm/gem: Take reservation lock for vmap/vunmap operations")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221020213335.309092-1-dmitry.osipenko@collabora.com

drm/gem: Take reservation lock for vmap/vunmap operations

The new common dma-buf locking convention will require buffer importers
to hold the reservation lock around mapping operations. Make DRM GEM core
to take the lock around the vmapping operations and update DRM drivers to
use the locked functions for the case where DRM core now holds the lock.
This patch prepares DRM core and drivers to the common dynamic dma-buf
locking convention.

Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221017172229.42269-4-dmitry.osipenko@collabora.com

drm/client: Use actual bpp when allocating frame buffers

When allocating a frame buffer, the number of bits per pixel needed is
derived from the deprecated drm_format_info.cpp[] field. While this may
work for formats using less than 8 bits per pixel, it does lead to a
large overallocation.

Reduce memory consumption by using the actual number of bits per pixel
instead.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/eabcf4f298184dabe46823fcf5ceffa1da0ec7ef.1657294931.git.geert@linux-m68k.org

dma-buf-map: Rename to iosys-map

Rename struct dma_buf_map to struct iosys_map and corresponding APIs.
Over time dma-buf-map grew up to more functionality than the one used by
dma-buf: in fact it's just a shim layer to abstract system memory, that
can be accessed via regular load and store, from IO memory that needs to
be acessed via arch helpers.

The idea is to extend this API so it can fulfill other needs, internal
to a single driver. Example: in the i915 driver it's desired to share
the implementation for integrated graphics, which uses mostly system
memory, with discrete graphics, which may need to access IO memory.

The conversion was mostly done with the following semantic patch:

@r1@
@@
- struct dma_buf_map
+ struct iosys_map

@r2@
@@
(
- DMA_BUF_MAP_INIT_VADDR
+ IOSYS_MAP_INIT_VADDR
|
- dma_buf_map_set_vaddr
+ iosys_map_set_vaddr
|
- dma_buf_map_set_vaddr_iomem
+ iosys_map_set_vaddr_iomem
|
- dma_buf_map_is_equal
+ iosys_map_is_equal
|
- dma_buf_map_is_null
+ iosys_map_is_null
|
- dma_buf_map_is_set
+ iosys_map_is_set
|
- dma_buf_map_clear
+ iosys_map_clear
|
- dma_buf_map_memcpy_to
+ iosys_map_memcpy_to
|
- dma_buf_map_incr
+ iosys_map_incr
)

@@
@@
- #include <linux/dma-buf-map.h>
+ #include <linux/iosys-map.h>

Then some files had their includes adjusted and some comments were
update to remove mentions to dma-buf-map.

Since this is not specific to dma-buf anymore, move the documentation to
the "Bus-Independent Device Accesses" section.

v2:
- Squash patches

v3:
- Fix wrong removal of dma-buf.h from MAINTAINERS
- Move documentation from dma-buf.rst to device-io.rst

v4:
- Change documentation title and level

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220204170541.829227-1-lucas.demarchi@intel.com

drm/client: Depend on GEM object kmap ref-counting

DRM client's vmap/vunmap functions don't allow for multiple vmap
operations. Calling drm_client_buffer_vmap() twice returns the same
mapping, then calling drm_client_buffer_vunmap() twice already unmaps
on the first call. This leads to unbalanced vmap refcounts. Fix this
by calling drm_gem_vmap() unconditionally in drm_client_buffer_vmap().

All drivers that support DRM clients have to implement correct ref-
counting for their vmap operations, or not vunmap at all. This is the
case for drivers that use CMA, SHMEM and VRAM helpers, and QXL. Other
drivers are not affected.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201120102545.4047-4-tzimmermann@suse.de

drm/gem: Store client buffer mappings as struct dma_buf_map

Kernel DRM clients now store their framebuffer address in an instance
of struct dma_buf_map. Depending on the buffer's location, the address
refers to system or I/O memory.

Callers of drm_client_buffer_vmap() receive a copy of the value in
the call's supplied arguments. It can be accessed and modified with
dma_buf_map interfaces.

v6:
* don't call page_to_phys() on framebuffers in I/O memory;
warn instead (Daniel)

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-9-tzimmermann@suse.de

drm/gem: Update internal GEM vmap/vunmap interfaces to use struct dma_buf_map

GEM's vmap and vunmap interfaces now wrap memory pointers in struct
dma_buf_map.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Tested-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201103093015.1063-8-tzimmermann@suse.de

drm/client: Add drm_client_framebuffer_flush()

Some drivers need explicit flushing of buffer changes, add a function
that does that.

v2:
- Put all clip rect stuff inside if statement (Sam)

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200509141619.32970-4-noralf@tronnes.org

drm: remove _unlocked suffix in drm_gem_object_put_unlocked

Spelling out _unlocked for each and every driver is a annoying.
Especially if we consider how many drivers, do not know (or need to)
about the horror stories involving struct_mutex.

Just drop the suffix. It makes the API cleaner.

Done via the following script:

__from=drm_gem_object_put_unlocked
__to=drm_gem_object_put
for __file in $(git grep --name-only $__from); do
sed -i "s/$__from/$__to/g" $__file;
done

Pay special attention to the compat #define

v2: keep sed and #define removal separate

Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org> (v1)
Reviewed-by: Steven Price <steven.price@arm.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20200515095118.2743122-14-emil.l.velikov@gmail.com

drm: convert .debugfs_init() hook to return void.

As a result of commit 987d65d01356 (drm: debugfs: make
drm_debugfs_create_files() never fail) and changes to various debugfs
functions in drm/core and across various drivers, there is no need for
the drm_driver.debugfs_init() hook to have a return value. Therefore,
declare it as void.

This also includes refactoring all users of the .debugfs_init() hook to
return void across the subsystem.

v2: include changes to the hook and drivers that use it in one patch to
prevent driver breakage and enable individual successful compilation of
this change.

References: https://lists.freedesktop.org/archives/dri-devel/2020-February/257183.html
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200310133121.27913-18-wambui.karugax@gmail.com

drm: make various debugfs_init() functions return 0

Since commit 987d65d01356 (drm: debugfs: make
drm_debugfs_create_files() never fail), drm_debugfs_create_files() never
fails and should return void. Therefore, remove its use as the
return value of various debugfs_init() functions in drm, and have these
functions return 0 directly.

v2: convert debugfs_init() functions to return 0 instead of void to
avoid build breakage.

References: https://lists.freedesktop.org/archives/dri-devel/2020-February/257183.html
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200310133121.27913-16-wambui.karugax@gmail.com

drm/client: Dual licence the file in GPL-2 and MIT

Contributors for this file are :
Chris Wilson <chris@chris-wilson.co.uk>
Denis Efremov <efremov@linux.com>
Jani Nikula <jani.nikula@intel.com>
Maxime Ripard <mripard@kernel.org>
Noralf Trønnes <noralf@tronnes.org>
Sam Ravnborg <sam@ravnborg.org>
Thomas Zimmermann <tzimmermann@suse.de>

Acked-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Denis Efremov <efremov@linux.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Maxime Ripard <mripard@kernel.org>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Emmanuel Vadot <manu@FreeBSD.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200215180911.18299-2-manu@FreeBSD.org

drm/client: convert to drm device based logging

Prefer drm_dbg_kms() and drm_err() over DRM_DEV_DEBUG_KMS() and
DRM_DEV_ERROR().

Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191210123050.8799-2-jani.nikula@intel.com

drm/fb-helper: Map DRM client buffer only when required

This patch changes DRM clients to not map the buffer by default. The
buffer, like any buffer object, should be mapped and unmapped when
needed.

An unmapped buffer object can be evicted to system memory and does
not consume video ram until displayed. This allows to use generic fbdev
emulation with drivers for low-memory devices, such as ast and mgag200.

This change affects the generic framebuffer console. HW-based consoles
map their console buffer once and keep it mapped. Userspace can mmap this
buffer into its address space. The shadow-buffered framebuffer console
only needs the buffer object to be mapped during updates. While not being
updated from the shadow buffer, the buffer object can remain unmapped.
Userspace will always mmap the shadow buffer.

v2:
* change DRM client to not map buffer by default
* manually map client buffer for fbdev with HW framebuffer

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/315830/
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

drm/client: Support unmapping of DRM client buffers

DRM clients, such as the fbdev emulation, have their buffer objects
mapped by default. Mapping a buffer implicitly prevents its relocation.
Hence, the buffer may permanently consume video memory while it's
allocated. This is a problem for drivers of low-memory devices, such as
ast, mgag200 or older framebuffer hardware, which will then not have
enough memory to display other content (e.g., X11).

This patch introduces drm_client_buffer_vmap() and _vunmap(). Internal
DRM clients can use these functions to unmap and remap buffer objects
as needed.

There's no reference counting for vmap operations. Callers are expected
to either keep buffers mapped (as it is now), or call vmap and vunmap
in pairs around code that accesses the mapped memory.

v2:
* remove several duplicated NULL-pointer checks
v3:
* style and typo fixes

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/315831/
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

drm/client: remove the exporting of drm_client_close

The function drm_client_close is declared as static and marked as
EXPORT_SYMBOL. It's a bit confusing for an internal function to be
exported. The area of visibility for such function is its .c file
and all other modules. Other *.c files of the same module can't use it,
despite all other modules can. Relying on the fact that this is the
internal function and it's not a crucial part of the API, the patch
removes the EXPORT_SYMBOL marking of drm_client_close.

Signed-off-by: Denis Efremov <efremov@linux.com>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190703170150.32548-1-efremov@linux.com

drm/fb-helper: Map DRM client buffer only when required

This patch changes DRM clients to not map the buffer by default. The
buffer, like any buffer object, should be mapped and unmapped when
needed.

An unmapped buffer object can be evicted to system memory and does
not consume video ram until displayed. This allows to use generic fbdev
emulation with drivers for low-memory devices, such as ast and mgag200.

This change affects the generic framebuffer console. HW-based consoles
map their console buffer once and keep it mapped. Userspace can mmap this
buffer into its address space. The shadow-buffered framebuffer console
only needs the buffer object to be mapped during updates. While not being
updated from the shadow buffer, the buffer object can remain unmapped.
Userspace will always mmap the shadow buffer.

v2:
* change DRM client to not map buffer by default
* manually map client buffer for fbdev with HW framebuffer

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/315830/

drm/client: Support unmapping of DRM client buffers

DRM clients, such as the fbdev emulation, have their buffer objects
mapped by default. Mapping a buffer implicitly prevents its relocation.
Hence, the buffer may permanently consume video memory while it's
allocated. This is a problem for drivers of low-memory devices, such as
ast, mgag200 or older framebuffer hardware, which will then not have
enough memory to display other content (e.g., X11).

This patch introduces drm_client_buffer_vmap() and _vunmap(). Internal
DRM clients can use these functions to unmap and remap buffer objects
as needed.

There's no reference counting for vmap operations. Callers are expected
to either keep buffers mapped (as it is now), or call vmap and vunmap
in pairs around code that accesses the mapped memory.

v2:
* remove several duplicated NULL-pointer checks
v3:
* style and typo fixes

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/315831/

drm/fb-helper: Remove drm_fb_helper_crtc

struct drm_fb_helper_crtc is now just a wrapper around drm_mode_set so
use that directly instead and attach it as a modeset array onto
drm_client_dev. drm_fb_helper will use this array to store its modesets
which means it will always initialize a drm_client, but it will not
register the client (callbacks) unless it's the generic fbdev emulation.

Code will later be moved to drm_client, so add code there in a new file
drm_client_modeset.c with MIT license to match drm_fb_helper.c.

The modeset connector array size is hardcoded for the cloned case to avoid
having to pass in a value from the driver. A value of 8 is chosen to err
on the safe side. This means that the max connector argument for
drm_fb_helper_init() and drm_fb_helper_fbdev_setup() isn't used anymore,
a todo entry for this is added.

In pan_display_atomic() restore_fbdev_mode_force() is used instead of
restore_fbdev_mode_atomic() because that one will later become internal
to drm_client_modeset.

Locking order:
1. drm_fb_helper->lock
2. drm_master_internal_acquire
3. drm_client_dev->modeset_mutex

v6: Improve commit message (Sam Ravnborg)

v3:
- Use full drm_client_init/release for the modesets (Daniel Vetter)
- drm_client_for_each_modeset: use lockdep_assert_held (Daniel Vetter)
- Hook up to Documentation/gpu/drm-client.rst (Daniel Vetter)

v2:
- Add modesets array to drm_client (Daniel Vetter)
- Use a new file for the modeset code (Daniel Vetter)
- File has to be MIT licensed (Emmanuel Vadot)
- Add copyrights from drm_fb_helper.c

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190531140117.37751-3-noralf@tronnes.org

drm: drop use of drmP.h in drm/*

The use of the drmP.h header file is deprecated.
Remove use from all files in drm/*
so people do not look there and follow a bad example.

Build tested allyesconfig,allmodconfig on x86, arm etc.
Including alpha that is as always more challenging than
the rest.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Sean Paul <sean@poorly.run>
Cc: David Airlie <airlied@linux.ie>
Link: https://patchwork.freedesktop.org/patch/msgid/20190526173535.32701-8-sam@ravnborg.org

drm: Remove users of drm_format_info_plane_cpp

drm_format_info_plane_cpp() basically just returns the cpp array content
found in the drm_format_info structure.

Since it's pretty trivial, let's remove the function and have the users use
the array directly

Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/c0a78c87cd0410a1819edad2794ad06543c85bb5.1558002671.git-series.maxime.ripard@bootlin.com

drm/fourcc: Pass the format_info pointer to drm_format_plane_cpp

So far, the drm_format_plane_cpp function was operating on the format's
fourcc and was doing a lookup to retrieve the drm_format_info structure and
return the cpp.

However, this is inefficient since in most cases, we will have the
drm_format_info pointer already available so we shouldn't have to perform a
new lookup. Some drm_fourcc functions also already operate on the
drm_format_info pointer for that reason, so the API is quite inconsistent
there.

Let's follow the latter pattern and remove the extra lookup while being a
bit more consistent. In order to be extra consistent, also rename that
function to drm_format_info_plane_cpp and to a static function in the
header to match the current policy.

Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/32aa13e53dbc98a90207fd290aa8e79f785fb11e.1558002671.git-series.maxime.ripard@bootlin.com

drm/client: Rename drm_client_add() to drm_client_register()

This is done to stay consistent with our naming scheme of
_register() = others can start calling us from any thread.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190403125658.32389-1-noralf@tronnes.org

drm/gem: Add drm_gem_object_funcs

This adds an optional function table on GEM objects.
The main benefit is for drivers that support more than one type of
memory (shmem,vram,cma) for their buffers depending on the hardware it
runs on. With the callbacks attached to the GEM object itself, it is
easier to have core helpers for the the various buffer types. The driver
only has to make the decision about buffer type on GEM object creation
and all other callbacks can be handled by the chosen helper.

drm_driver->gem_prime_res_obj has not been added since there's a todo to
put a reservation_object into drm_gem_object.

v3: Add todo entry

v2: Drop drm_gem_object_funcs->prime_mmap in favour of
drm_gem_prime_mmap() (Daniel Vetter)

v1:
- drm_gem_object_funcs.map -> .prime_map let it only do PRIME mmap like
the function it superseeds (Daniel Vetter)
- Flip around the if ladders and make obj->funcs the first choice
highlighting the fact that this the new default way of doing it
(Daniel Vetter)

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181110145647.17580-4-noralf@tronnes.org

drm/cma-helper: Fix crash in fbdev error path

Sergey Suloev reported a crash happening in drm_client_dev_hotplug()
when fbdev had failed to register.

[ 9.124598] vc4_hdmi 3f902000.hdmi: ASoC: Failed to create component debugfs directory
[ 9.147667] vc4_hdmi 3f902000.hdmi: vc4-hdmi-hifi <-> 3f902000.hdmi mapping ok
[ 9.155184] vc4_hdmi 3f902000.hdmi: ASoC: no DMI vendor name!
[ 9.166544] vc4-drm soc:gpu: bound 3f902000.hdmi (ops vc4_hdmi_ops [vc4])
[ 9.173840] vc4-drm soc:gpu: bound 3f806000.vec (ops vc4_vec_ops [vc4])
[ 9.181029] vc4-drm soc:gpu: bound 3f004000.txp (ops vc4_txp_ops [vc4])
[ 9.188519] vc4-drm soc:gpu: bound 3f400000.hvs (ops vc4_hvs_ops [vc4])
[ 9.195690] vc4-drm soc:gpu: bound 3f206000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.203523] vc4-drm soc:gpu: bound 3f207000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.215032] vc4-drm soc:gpu: bound 3f807000.pixelvalve (ops vc4_crtc_ops [vc4])
[ 9.274785] vc4-drm soc:gpu: bound 3fc00000.v3d (ops vc4_v3d_ops [vc4])
[ 9.290246] [drm] Initialized vc4 0.0.0 20140616 for soc:gpu on minor 0
[ 9.297464] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013).
[ 9.304600] [drm] Driver supports precise vblank timestamp query.
[ 9.382856] vc4-drm soc:gpu: [drm:drm_fb_helper_fbdev_setup [drm_kms_helper]] *ERROR* Failed to set fbdev configuration
[ 10.404937] Unable to handle kernel paging request at virtual address 00330a656369768a
[ 10.441620] [00330a656369768a] address between user and kernel address ranges
[ 10.449087] Internal error: Oops: 96000004 [#1] PREEMPT SMP
[ 10.454762] Modules linked in: brcmfmac vc4 drm_kms_helper cfg80211 drm rfkill smsc95xx brcmutil usbnet drm_panel_orientation_quirks raspberrypi_hwmon bcm2835_dma crc32_ce pwm_bcm2835 bcm2835_rng virt_dma rng_core i2c_bcm2835 ip_tables x_tables ipv6
[ 10.477296] CPU: 2 PID: 45 Comm: kworker/2:1 Not tainted 4.19.0-rc5 #3
[ 10.483934] Hardware name: Raspberry Pi 3 Model B Rev 1.2 (DT)
[ 10.489966] Workqueue: events output_poll_execute [drm_kms_helper]
[ 10.596515] Process kworker/2:1 (pid: 45, stack limit = 0x000000007e8924dc)
[ 10.603590] Call trace:
[ 10.606259] drm_client_dev_hotplug+0x5c/0xb0 [drm]
[ 10.611303] drm_kms_helper_hotplug_event+0x30/0x40 [drm_kms_helper]
[ 10.617849] output_poll_execute+0xc4/0x1e0 [drm_kms_helper]
[ 10.623616] process_one_work+0x1c8/0x318
[ 10.627695] worker_thread+0x48/0x428
[ 10.631420] kthread+0xf8/0x128
[ 10.634615] ret_from_fork+0x10/0x18
[ 10.638255] Code: 54000220 f9401261 aa1303e0 b4000141 (f9400c21)
[ 10.644456] ---[ end trace c75b4a4b0e141908 ]---

The reason for this is that drm_fbdev_cma_init() removes the drm_client
when fbdev registration fails, but it doesn't remove the client from the
drm_device client list. So the client list now has a pointer that points
into the unknown and we have a 'use after free' situation.

Split drm_client_new() into drm_client_init() and drm_client_add() to fix
removal in the error path.

Fixes: 894a677f4b3e ("drm/cma-helper: Use the generic fbdev emulation")
Reported-by: Sergey Suloev <ssuloev@orpaltech.com>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20181001194536.57756-1-noralf@tronnes.org

drm: Differentiate the lack of an interface from invalid parameter

If the ioctl is not supported on a particular piece of HW/driver
combination, report ENOTSUP (aka EOPNOTSUPP) so that it can be easily
distinguished from both the lack of the ioctl and from a regular invalid
parameter.

v2: Across all the kms ioctls we had a mixture of reporting EINVAL,
ENODEV and a few ENOTSUPP (most where EINVAL) for a failed
drm_core_check_feature(). Update everybody to report ENOTSUPP.

v3: ENOTSUPP is an internal errno! It's value (524) does not correspond
to a POSIX errno, the one we want is ENOTSUP. However,
uapi/asm-generic/errno.h doesn't include ENOTSUP but man errno says

"ENOTSUP and EOPNOTSUPP have the same value on Linux,
but according to POSIX.1 these error values should be
distinct."

so use EOPNOTSUPP as its equivalent.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> #v2
Link: https://patchwork.freedesktop.org/patch/msgid/20180913192050.24812-1-chris@chris-wilson.co.uk

drm/client: Fix double free in error path

This fixes a static checker warning:

drivers/gpu/drm/drm_client.c:289 drm_client_buffer_create()
error: double free of 'buffer'

Extend drm_client_buffer_delete() to handle the case when there's no
dumb buffer attached and drop the extra kfree.

Fixes: c76f0f7cb546 ("drm: Begin an API for in-kernel clients")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712150414.46908-1-noralf@tronnes.org

drm/client: Fix: drm_client_new: Don't require DRM to be registered

Commit 894a677f4b3e ("drm/cma-helper: Use the generic fbdev emulation")
broke almost all drivers that use the CMA helper.

The reason is that drm_client_new() requires that the DRM device has
been registered, but the drivers register fbdev before registering DRM.

Remove the requirement that DRM should be registered when creating a
new client.

Fixes: c76f0f7cb546 ("drm: Begin an API for in-kernel clients")
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Icenowy Zheng <icenowy@aosc.io>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Tested-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180711155632.37437-1-noralf@tronnes.org

drm/debugfs: Add internal client debugfs file

Print the names of the internal clients currently attached.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180703160354.59955-6-noralf@tronnes.org

drm: Begin an API for in-kernel clients

This the beginning of an API for in-kernel clients.
First out is a way to get a framebuffer backed by a dumb buffer.

Only GEM drivers are supported.
The original idea of using an exported dma-buf was dropped because it
also creates an anonomous file descriptor which doesn't work when the
buffer is created from a kernel thread. The easy way out is to use
drm_driver.gem_prime_vmap to get the virtual address, which requires a
GEM object. This excludes the vmwgfx driver which is the only non-GEM
driver apart from the legacy ones. A solution for vmwgfx will have to be
worked out later if it wants to support the client API which it probably
will when we have a bootsplash client.

Suggested-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180703160354.59955-2-noralf@tronnes.org