The drm driver .load() operation is prone to race conditions as it
initializes the driver after registering the device nodes. Its usage is
deprecated, inline it in the probe function and call drm_dev_alloc() and
drm_dev_register() explicitly.

For consistency inline the .unload() handler in the remove function as
well.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

The DRM core supports skipping plane update for inactive CRTCs for
hardware that don't need it or can't cope with it. That's our case, and
the driver already skips flushing planes on inactice CRTCs.

We can't remove the check from the driver, as active CRTCs are disabled
at the hardware level when an atomic flush is performed if a mode set is
pending. There's however no need to forward the plane commit calls to
the driver, so use the DRM core infrastructure to skip them with a
detailed comment to explain why the check must still be kept in the
driver.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

As the FIFO underflow IRQ handler just prints an error message to the
kernel log, simplify the code by not registering one IRQ handler per
plane but print the messages directly from the main IRQ handler.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

We set the possible_crtc for all planes to "(1 << priv->num_crtcs) - 1",
which is fine as the HW planes can be used fro all crtcs. However, when
we're doing that, we are still incrementing 'num_crtcs', and we'll end
up with bad possible_crtcs, preventing the use of the primary planes.

This patch passes a possible_crtcs mask to plane init function so that
we get correct possible_crtc.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

The global mode_config.rotation_property is going away, switch over to
per-plane rotation_property.

Not sure I got the annoying crtc rotation_property handling right.
Might work, or migth not.

v2: Drop the BIT()
    Don't create rotation property twice for each primary plane

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
[danvet: Add comment per discussion between Tomi&Ville.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1474907460-10717-8-git-send-email-ville.syrjala@linux.intel.com

0 isn't a valid rotation property value, so let's set the initial value
of the property to BIT(DRM_ROTATE_0) instead.

v2: Drop the BIT()

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: Rob Clark <robdclark@gmail.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1474907460-10717-7-git-send-email-ville.syrjala@linux.intel.com

drm_atomic_state has a complicated single owner model that tracks the
single reference from allocation through to destruction on another
thread - or perhaps on a local error path. We can simplify this tracking
by using reference counting (at a cost of a few more atomics). This is
even more beneficial when the lifetime of the state becomes more
convoluted than being passed to a single worker thread for the commit.

v2: Double check !intel atomic_commit functions for missing gets
v3: Update kerneldocs
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: NEric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: NSean Paul <seanpaul@chromium.org>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161014121833.439-27-chris@chris-wilson.co.uk

Drivers may set the NO_DISABLE_AFTER_MODESET flag in the 'flags' parameter
of the helper drm_atomic_helper_commit_planes() if the relevant display
controllers(e.g., IPUv3 for imx-drm) require to disable a CRTC's planes
when the CRTC is disabled. The helper would skip the ->atomic_disable
call for a plane if the CRTC of the old plane state needs a modesetting
operation. Of course, the drivers need to disable the planes in their CRTC
disable callbacks since no one else would do that.
Suggested-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: Philipp Zabel <p.zabel@pengutronix.de>
Cc: David Airlie <airlied@linux.ie>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Peter Senna Tschudin <peter.senna@gmail.com>
Cc: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: NLiu Ying <gnuiyl@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1472461923-14364-1-git-send-email-gnuiyl@gmail.com

Only property creation uses the rotation as an index, so convert the
to figure the index when needed.

v2: Use the new defines to build the _MASK defines (Sean)

Cc: intel-gfx@lists.freedesktop.org
Cc: linux-arm-msm@vger.kernel.org
Cc: freedreno@lists.freedesktop.org
Cc: malidp@foss.arm.com
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Liviu Dudau <Liviu.Dudau@arm.com>
Cc: Sean Paul <seanpaul@chromium.org>
Acked-by: NLiviu Dudau <Liviu.Dudau@arm.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: NSean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1469771405-17653-1-git-send-email-joonas.lahtinen@linux.intel.com

We already have a fallback in place to fill out the unique from
dev->unique, which is set to something reasonable in drm_dev_alloc.

Which means we only need to have a special set_busid for pci devices,
to be able to care the backwards compat code for drm 1.1 around, which
libdrm still needs.

While developing and testing this patch things blew up in really
interesting ways, and the code is rather confusing in naming things
between the kernel code, ioctl #defines and libdrm. For the next brave
dragon slayer, document all this madness properly in the userspace
interface section of gpu.tmpl.

v2: Make drm_dev_set_unique static and update kerneldoc.

v3: Entire rewrite, plus document what's going on for posterity in the
gpu docbook uapi section.

v4: Drop accidental amdgpu hunk (Emil).

v5: Drop accidental omapdrm vblank counter change (Emil).

v6: Rebase on top of the sphinx conversion.

Cc: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Tested-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk> (virt_gpu)
Reviewed-by: NEmil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

- dev is redundant, we have state->atomic
- add stall parameter, which must be set when swapping needs to stall
  for preceeding commits to stop looking at ->state pointers. Currently
  all drivers need this to be, just prep work for a glorious future.

v2: Rebased on top of

commit e7cf0963
Author: Gerd Hoffmann <kraxel@redhat.com>
Date:   Tue May 31 08:50:47 2016 +0200

    virtio-gpu: add atomic_commit function

Cc: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1465509992-19284-1-git-send-email-daniel.vetter@ffwll.ch
Link: http://patchwork.freedesktop.org/patch/msgid/1465388359-8070-2-git-send-email-daniel.vetter@ffwll.ch

This sets proper connector type for DSI connected panels.
Signed-off-By: NSebastian Reichel <sre@kernel.org>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

We want to hide drm_atomic_stat internals a bit better.

v2: Use drm_crtc_mask (Maarten).

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1464818821-5736-7-git-send-email-daniel.vetter@ffwll.ch

drm_gem_object_lookup() has never required the drm_device for its file
local translation of the user handle to the GEM object. Let's remove the
unused parameter and save some space.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: dri-devel@lists.freedesktop.org
Cc: Dave Airlie <airlied@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
[danvet: Fixup kerneldoc too.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The async name is deprecated and should be changed to nonblocking.

Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1461679905-30177-7-git-send-email-maarten.lankhorst@linux.intel.com

In order to remove uses of 'struct omap_overlay_manager' we need to get
rid of using omapdss_find_mgr_from_display() when initializing omapdrm.

Instead of using omapdss_find_mgr_from_display() and mgr->id to find the
dispc channel used for the given display, we can instead use
omapdss_find_output_from_display(), and get the output->dispc_channel
from there.

We can also remove omapdss_find_mgr_from_display() as it's no longer
used.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

For legacy reasons omapdss handles system suspend/resume via PM notifier
callback, where the driver disables/resumes all the outputs.

This doesn't work well with omapdrm. What happens on suspend is that the
omapdss disables the displays while omapdrm is still happily continuing
its work, possibly waiting for an vsync irq, which will never come if
the display output is disabled, leading to timeouts and errors sent to
userspace.

This patch moves the suspend/resume handling to omapdrm, and the
suspend/resume is now done safely inside modeset lock.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Again since the core takes care of this we can remove them. While at
it also remove the postclose hook, it's empty.

v2: Laurent pointed me at even more code to delete.

v3: Remove unused flags (Tomi).

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NDaniel Stone <daniels@collabora.com>
Reviewed-by: NAlex Deucher <alexander.deucher@amd.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1453756616-28942-9-git-send-email-daniel.vetter@ffwll.ch

omapdrm supports atomic modesetting, and it seems to work ok. So let's
set the flag to enable the atomic modesetting API support.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>

The 8 high order bits of the buffer flags are reserved for internal use.
Mask them out from the flags passed by userspace.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Don't compile the fbdev emulation code when fbdev emulation support is
disabled.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

These new helpers simplify implementing multi-driver modules and
properly handle failure to register one driver by unregistering all
previously registered drivers.
Signed-off-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Just one special case (since i915 lost its ums code, yay):
- radeon: Has slots for the old ums ioctls which don't have
  DRM_UNLOCKED, but all filled with drm_invalid_op. So ok to drop it
  everywhere.

Every other kms driver just has DRM_UNLOCKED for all their ioctls, as
they should.

v2: admgpu happened, include that one too. And i915 lost its UMS
support which means we can change all the i915 ioctls too.

v3: Rebased on top of new vmwgfx DX interface extensions.

v4: Rebase on top of render-node support in exynos.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NDavid Herrmann <dh.herrmann@gmail.com>
Reviewed-by: NChristian König <christian.koenig@amd.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drm_vblank_count() returns the software counter. We should not pretend
it's the hw counter since we use the hw counter to figuere out what the
software counter value should be. So instead provide a new function
drm_vblank_no_hw_counter() for drivers that don't have a real hw
counter. The new function simply returns 0, which is about the only
thing it can do.

Cc: Vincent Abriou <vincent.abriou@st.com>
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVincent Abriou <vincent.abriou@st.com>
[danvet: s/int pipe/unsigned int pipe/ to follow Thierry's interface
change.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Currently everyone and their dog has their own favourite spelling
for vga_switcheroo. This makes it hard to grep dmesg for log entries
relating to vga_switcheroo. It also makes it hard to find related
source files in the tree.

vga_switcheroo.c uses pr_fmt "vga_switcheroo". Use that everywhere.
Signed-off-by: NLukas Wunner <lukas@wunner.de>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With drivers supporting runtime pm it's generally not a good idea to
touch the hardware when it's off. Add an option to the commit_planes
helper to support this case.

Note that the helpers already add all planes on a crtc when a modeset
happens, hence plane updates will not be lost if drivers set this to
true.

v2: Check for NULL state->crtc before chasing the pointer. Also check
both old and new crtc if there's a switch. Finally just outright
disallow switching crtcs for a plane if the plane is in active use, on
most hardware that doesn't make sense.

v3: Since commit_planes(active_only = true) is for enabling things
only after all the crtc are on we should only look at the new crtc to
decide whether to call the plane hooks - if the current CRTC isn't on
then skip. If the old crtc (when moving a plane) went down then the
plane should have been disabled as part of the pipe shutdown work
already. For which there's currently no helper really unfortunately.
Also move the check for wether a plane gets a new CRTC assigned while
still in active use out of this patch.

v4: Rebase over exynos changes.

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Tested-by: NThierry Reding <treding@nvidia.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

Rework the crtc event/flip_wait system as follows:

- If we enable a crtc (full modeset), we set omap_crtc->pending and
  register vblank irq.

- If we need to set GO bit (page flip), we do the same but also set the
  GO bit.

- On vblank we unregister the irq, clear the 'pending' flag, send vblank
  event to userspace if crtc->state->event != NULL, and wake up
  'pending_wait' wq.

- In omap_atomic_complete() we wait for the 'pending' flag to get reset
  for all enabled crtcs  using 'pending_wait' wq.

The above ensures that we send the events to userspace in vblank, and
that after the wait in omap_atomic_complete() everything for the
affected crtcs has been completed.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>

Instead of sprinkling dispc_runtime_get() and dispc_runtime_put() calls
in various CRTC operations, move all power management code to the atomic
commit function.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

DRM page flip vblank events requested by page flips or atomic commits
are created by the DRM core and then passed to driver through CRTC
states (for atomic commit) or directly to the page flip handler (for
legacy page flips). The events are then kept aside until the page flip
completes, at which point drivers queue them for delivery with a call to
drm_send_vblank_event().

When a DRM file handle is closed events pending for delivery are cleaned
up automatically by the DRM core. Events that have been passed to the
driver but haven't completed yet, however, are not handled by the DRM
core. Drivers are responsible for destroying them and must not attempt
to queue them for delivery. This is usually handled by drivers'
preclose() handlers that cancel and destroy page flip events that
reference the file handle being closed.

With asynchronous atomic updates the story becomes more complex. Several
asynchronous atomic updates can be pending, each of them carrying
per-CRTC events. As the atomic_commit() operation doesn't receive a file
handle context, drivers can't know which file handle a pending update
refers to, making it difficult to cancel or wait for completion of
updates related to the file handle being closed.

It should be noted that cancelling page flips or waiting for atomic
updates completion isn't required by the DRM core when closing a file
handle. The only requirement is that no event gets queued for delivery
after the preclose() operation returns. This can easily be achieved by
storing events for atomic commits in a list, unlinking events from the
file handle being closed by setting the file_priv field to NULL, and
skipping delivery of unlinked events.

This logic replaces the page flip cancellation completely.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Implement a custom .atomic_commit() handler that supports asynchronous
commits using a work queue. This can be used for userspace-driven
asynchronous commits, as well as for an atomic page flip implementation.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

This removes the legacy plane update code. Wire up the default atomic
check and atomic commit mode config helpers as needed by the plane
update atomic helpers.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Hook up the default .reset(), .atomic_duplicate_state() and
.atomic_free_state() helpers to ensure that state objects are properly
created and destroyed, and call drm_mode_config_reset() at init time to
create the initial state objects.

Framebuffer reference count also gets maintained automatically by the
transitional helpers except for the legacy page flip operation. Maintain
it explicitly there.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Use the <...> include style instead of "..." for DRM headers and sort
the headers alphabetically to ease detection of duplicates.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

The DRM core vblank handling mechanism requires drivers to forcefully
turn vblank reporting off when disabling the CRTC, and to restore the
vblank reporting status when enabling the CRTC.

Implement this using the drm_crtc_vblank_on/off helpers. When disabling
vblank we must first wait for page flips to complete, so implement page
flip completion wait as well.

Finally, drm_crtc_vblank_off() must be called at startup to synchronize
the state of the vblank core code with the hardware, which is initially
disabled. An interesting side effect is that the .disable_vblank()
operation will now be called for the first time with the CRTC disabled
and the DISPC runtime suspended. The dispc_runtime_get() call in
.disable_vblank() is supposed to take care of that, but the operation is
called with a spinlock held, which prevents it from sleeping.

To fix that move DISPC runtime PM handling out of the vblank operations
to the CRTC code, ensuring that the display controller will always be
powered when enabling or disabling vblank interrupts.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Pending page flips must be cancelled when closing the device, otherwise
their completion at next vblank will result in nasty effects, including
possible oopses due to resources required to complete the page flip
being freed.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

The omapdrm can't use drm_irq_install() and drm_irq_uninstall() as it
delegates IRQ handling to the omapdss driver. However, the code still
declares IRQ-related operations used by the DRM IRQ helpers, and calls
them indirectly.

Simplify the implementation by calling the functions directly or
inlining them. The irq_enabled checks can then also be simplified as
the call stacks guarantees that omap_drm_irq_install() and
omap_drm_irq_uninstall() will never run concurrently.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

The omapdrm driver implements a mechanism to apply new settings (due to
plane update, plane disable, plane property set, CRTC mode set or CRTC
DPMS) asynchronously. While this improves performance, it adds a level
of complexity that makes transition to the atomic update API close to
impossible. Furthermore the atomic update API requires part of the apply
operations to be synchronous (such as pinning the framebuffers), so the
current implementation needs to be changed.

Simplify the CRTC and plane code by making updates synchronous to
prepare for the switch to the atomic update API. Asynchronous update
will be implemented in a second step.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Rotation is a standard property, store it in
dev->mode_config.rotation_property. While at it, extract the properties
initialization code to a separate function instead of running it for
every plane.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

Setting a dev_pm_ops suspend/resume pair but not a set of hibernation
functions means those pm functions will not be called upon hibernation.

Fix this by using SIMPLE_DEV_PM_OPS, which appropriately assigns the
suspend and hibernation handlers and move
omap_drm_suspend/omap_drm_resume under CONFIG_PM_SLEEP to avoid build
warnings.
Signed-off-by: NGrygorii Strashko <Grygorii.Strashko@linaro.org>
[tomi.valkeinen@ti.com: fix conflict, clean up description]
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

omap_gem_objects are added to dev->obj_list in omap_gem_new, and removed
in omap_gem_free_object. Unfortunately there's no locking for
dev->obj_list, which eventually leads to a crash:

WARNING: CPU: 1 PID: 1123 at lib/list_debug.c:59 __list_del_entry+0xa4/0xe0()
list_del corruption. prev->next should be e9281344, but was ea722b84

Add a spinlock to protect dev->obj_list.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>