It is a bad idea for i915_add_request() to fail. The work will already have been
send to the ring and will be processed, but there will not be any tracking or
management of that work.

The only way the add request call can fail is if it can't write its epilogue
commands to the ring (cache flushing, seqno updates, interrupt signalling). The
reasons for that are mostly down to running out of ring buffer space and the
problems associated with trying to get some more. This patch prevents that
situation from happening in the first place.

When a request is created, it marks sufficient space as reserved for the
epilogue commands. Thus guaranteeing that by the time the epilogue is written,
there will be plenty of space for it. Note that a ring_begin() call is required
to actually reserve the space (and do any potential waiting). However, that is
not currently done at request creation time. This is because the ring_begin()
code can allocate a request. Hence calling begin() from the request allocation
code would lead to infinite recursion! Later patches in this series remove the
need for begin() to do the allocate. At that point, it becomes safe for the
allocate to call begin() and really reserve the space.

Until then, there is a potential for insufficient space to be available at the
point of calling i915_add_request(). However, that would only be in the case
where the request was created and immediately submitted without ever calling
ring_begin() and adding any work to that request. Which should never happen. And
even if it does, and if that request happens to fall down the tiny window of
opportunity for failing due to being out of ring space then does it really
matter because the request wasn't doing anything in the first place?

v2: Updated the 'reserved space too small' warning to include the offending
sizes. Added a 'cancel' operation to clean up when a request is abandoned. Added
re-initialisation of tracking state after a buffer wrap to keep the sanity
checks accurate.

v3: Incremented the reserved size to accommodate Ironlake (after finally
managing to run on an ILK system). Also fixed missing wrap code in LRC mode.

v4: Added extra comment and removed duplicate WARN (feedback from Tomas).

For: VIZ-5115
CC: Tomas Elf <tomas.elf@intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Backmerge drm-next because the conflict between Ander's atomic fixes
for 4.2 and Maartens future work are getting to unwielding to handle.

Conflicts:
	drivers/gpu/drm/i915/intel_display.c
	drivers/gpu/drm/i915/intel_ringbuffer.h

Just always take ours, same as git merge -X ours, but done by hand
because I didn't trust git: It's confusing that it doesn't show any
conflicts in the merge diff at all.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

In Indirect context w/a batch buffer,
+WaFlushCoherentL3CacheLinesAtContextSwitch:bdw

v2: Add LRI commands to set/reset bit that invalidates coherent lines,
update WA to include programming restrictions and exclude CHV as
it is not required (Ville)

v3: Avoid unnecessary read when it can be done by reading register once (Chris).

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In Indirect and Per context w/a batch buffer,
+WaDisableCtxRestoreArbitration

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some of the WA applied using WA batch buffers perform writes to scratch page.
In the current flow WA are initialized before scratch obj is allocated.
This patch reorders intel_init_pipe_control() to have a valid scratch obj
before we initialize WA.

v2: Check for valid scratch page before initializing WA as some of them
perform writes to it.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: NMichel Thierry <michel.thierry@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Some of the WA are to be applied during context save but before restore and
some at the end of context save/restore but before executing the instructions
in the ring, WA batch buffers are created for this purpose and these WA cannot
be applied using normal means. Each context has two registers to load the
offsets of these batch buffers. If they are non-zero, HW understands that it
need to execute these batches.

v1: In this version two separate ring_buffer objects were used to load WA
instructions for indirect and per context batch buffers and they were part
of every context.

v2: Chris suggested to include additional page in context and use it to load
these WA instead of creating separate objects. This will simplify lot of things
as we need not explicity pin/unpin them. Thomas Daniel further pointed that GuC
is planning to use a similar setup to share data between GuC and driver and
WA batch buffers can probably share that page. However after discussions with
Dave who is implementing GuC changes, he suggested to use an independent page
for the reasons - GuC area might grow and these WA are initialized only once and
are not changed afterwards so we can share them share across all contexts.

The page is updated with WA during render ring init. This has an advantage of
not adding more special cases to default_context.

We don't know upfront the number of WA we will applying using these batch buffers.
For this reason the size was fixed earlier but it is not a good idea. To fix this,
the functions that load instructions are modified to report the no of commands
inserted and the size is now calculated after the batch is updated. A macro is
introduced to add commands to these batch buffers which also checks for overflow
and returns error.
We have a full page dedicated for these WA so that should be sufficient for
good number of WA, anything more means we have major issues.
The list for Gen8 is small, same for Gen9 also, maybe few more gets added
going forward but not close to filling entire page. Chris suggested a two-pass
approach but we agreed to go with single page setup as it is a one-off routine
and simpler code wins.

One additional option is offset field which is helpful if we would like to
have multiple batches at different offsets within the page and select them
based on some criteria. This is not a requirement at this point but could
help in future (Dave).

Chris provided some helpful macros and suggestions which further simplified
the code, they will also help in reducing code duplication when WA for
other Gen are added. Add detailed comments explaining restrictions.
Use do {} while(0) for wa_ctx_emit() macro.

(Many thanks to Chris, Dave and Thomas for their reviews and inputs)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NArun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If the user disables the GPU reset using the i915.reset parameter and
one occurs, report that we failed to reset the GPU. If we return early,
as we currently do, then we leave all state intact (with a hung GPU)
and clients block forever waiting for their requests to complete.

Testcase: igt/gem_eio
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: Mark i915.reset as an unsafe modoption, as discussed with
Chris.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The module pciid list got lost, but somehow most distros seem to
force-load drm drivers early and no one noticed for a while.

Bug introduced in

commit fd930478
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jun 19 20:27:27 2015 +0100

    drm/i915: Remove KMS Kconfig option
Reported-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>

If we are doing an MST transaction and we've gotten HPD and we
lookup the device from the incoming msg, we should take the mgr
lock around it, so that mst_primary and mstb->ports are valid.
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

This validates the mst_primary under the lock, and then calls
into the check and send function. This makes the code a lot
easier to understand the locking rules in.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: NDave Airlie <airlied@redhat.com>

Merge tag 'drm-intel-next-fixes-2015-06-22' of git://anongit.freedesktop.org/drm-intel into drm-next

fix warning introduced in last -fixes
* tag 'drm-intel-next-fixes-2015-06-22' of git://anongit.freedesktop.org/drm-intel:
  drm/i915: Silence compiler warning

This symbol came via exynos-next, but modular builds are broken
so just fix it up now.
Signed-off-by: NDave Airlie <airlied@redhat.com>

Merge branch 'exynos-drm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos into drm-next

Summary:
. Add atomic feature support
  - Exynos also now supports atomic feature. However, it doesn't
    guarantee atomic operation yet, and is required for more cleanups.
    This time we just modified for Exynos drm driver to use atomic
    interfaces instead of legacy ones. Next time, we will enhance
    Exynos drm driver to support the atomic operation.
. Add iommu support
  - This is a patch series according to below Exynos iommu integration
    work with DT and dma-mapping subsystem,
    http://lwn.net/Articles/607626/
. Consolidate Exynos drm driver initialization.
  - This patch sereis resolves the issue that only the first compoments
    was bound when happened deferred probing for other pipelines and
    also makes the driver to be more cleanned up by moving the dispered
    codes for registering kms drivers to one place.
. Add new MIC, DECON drivers, and MIPI-DSI support for Exynos5433.
  - Add MIC(Mobile image compressor) driver. MIC is a new IP for Exynos5433
    and later, which is used to transfer frame data to MIPI-DSI controller
    compressing the data to reduce memory bandwidth.
  - Add DECON driver for Exynos5433 SoC. This IP is a dislay controller
    similar to Exynos7's one but this controller has much different registers
    from Exynos7's ones so this driver has been implemented separately.
    We will implement a helper modules for FIMD and two DECON controllers
    to remove duplicated codes later.
  - Add Exynos5433 SoC support to MIPI-DSI driver, and device tree
    relevant patches.

* 'exynos-drm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/daeinki/drm-exynos: (50 commits)
  ARM: dts: rename the clock of MIPI DSI 'pll_clk' to 'sclk_mipi'
  drm/exynos: dsi: do not set TE GPIO direction by input
  drm/exynos: dsi: add support for MIC driver as a bridge
  drm/exynos: dsi: add support for Exynos5433
  drm/exynos: dsi: make use of array for clock access
  drm/exynos: dsi: make use of driver data for static values
  drm/exynos: dsi: add macros for register access
  drm/exynos: dsi: rename pll_clk to sclk_clk
  drm/exynos: mic: add MIC driver
  of: add helper for getting endpoint node of specific identifiers
  drm/exynos: add Exynos5433 decon driver
  drm/exynos: fix the input prompt of Exynos7 DECON
  drm/exynos: add drm_iommu_attach_device_if_possible()
  drm/exynos: Add the dependency for DRM_EXYNOS to DPI/DSI/DP
  drm/exynos: remove the dependency of DP driver for ARCH_EXYNOS
  drm/exynos: do not wait for vblank at atomic operation
  drm/exynos: Remove unused vma field of exynos_drm_gem_obj
  drm/exynos: fimd: fix page fault issue with iommu
  drm/exynos: iommu: improve a check for non-iommu dma_ops
  drm/exynos: iommu: detach from default dma-mapping domain on init
  ...

One more drm-misc pull for 4.2. The important one is the fix from Laurent
for Daniel Stone's mode_blob work.

* tag 'topic/drm-misc-2015-06-22' of git://anongit.freedesktop.org/drm-intel:
  drm/atomic: Don't set crtc_state->enable manually
  drm: prime: Document gem_prime_mmap
  drm: Avoid the double clflush on the last cache line in drm_clflush_virt_range()
  drm/atomic: Extract needs_modeset function
  drm/cma: Fix 64-bit size_t build warnings
  Documentation/drm: Update rotation property

Since we only support modesetting by default (disabling modesetting on
the command line prevents i915.ko from loading), having a parameter to
disable modesstting by default is superfluous, i.e. saying
CONFIG_DRM_I915_KMS=n is equivalent to CONFIG_DRM_I915=n.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Veter <daniel.vetter@ffwll.ch>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On older gen, pre-Ironlake, parts there is no hardwired pin to report
the presence of an LVDS panel. Instead, we have to rely on the VBT to
declare whether the machine has a panel or not. Though notoriously
unreliable, so far we have erred on the side of false-positives and have
required a list of machines which end up falsely reporting a panel as
present. However, we now have reports of false-negatives, machines with
an LVDS that are being ignored due to the VBT not declaring the panel.
This patch ignores the VBT setting if the BIOS has already enabled the
LVDS panel (and on Ironlake+ we also have the hardware presence pin).

It fixes the Samsung NP680Z5E-X01FR in the bug report, but is likely to
result in more false-positives, and since we rely on the BIOS to enable
the panel, there are likely different circumstances where the BIOS will
not enable that panel (and so we may see the same machine with and
without a panel all on the whim of the BIOS).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90979
Reported-and-tested-by: lysxia@gmail.com
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Internal requirement for the alignment is that it must be a
power-of-two, so enforce rejection at the user interface to execbuffer
(which allows the caller to specify a stricter-than-expected alignment
criterion).
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This patch doesn't have any functional change, but organize fruntbuffer
invalidate and busy by removing unecesarry signature argument for ring.

It was unsed on mark_fb_busy and only used on fb_obj_invalidate for the
same ORIGIN_CS usage. So let's clean it a bit

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The same dpll p2 divider selection is repeated three times in the
gen2-4 .find_dpll() functions. Factor it out.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Make Paulo happier.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We have enough generic hotplug functions sprinkled all over i915_irq.c
to warrant moving them to a file of their own. This should further
underline the distinction between generic code in the new file and
platform specific hotplug and irq code that remains in i915_irq.c.

Add new intel_hpd_init_work to keep work functions static, and rename
get_port_from_pin to intel_hpd_pin_to_port while increasing its
visibility, but keep everything else the same.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We'll have three functions:

intel_hpd_irq_storm_detect for detecting irq storms,
intel_hpd_irq_storm_disable for disabling hotplugs after detected storms,
intel_hpd_irq_storm_reenable_work for re-enabling hotplug.

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Continue abstracting hotplug storm related functions to clarify the
code. This time, abstract hotplug irq storm related hotplug
disabling. While at it, clean up the loop iterating over connectors for
readability.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The hotplug work function has two loops iterating over connectors, the
first for handling hotplug disabling due to irq storms and the second
for actually handling the hotplug events. Move the debug printing into
the second one, so we can abstract the storm handling better. This may
change the output ordering slightly when there are multiple simultaneous
hotplug events.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The clock which was named as 'pll_clk' is actually not the clock source
of PLL in MIPI DSI. This patch fixes this disagreement.
Signed-off-by: NHyungwon Hwang <human.hwang@samsung.com>
Acked-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NInki Dae <inki.dae@samsung.com>

The skylake scalers depend on the cdclk freq, but that frequency can
change during a modeset. So when a modeset happens calculate the new
cdclk in the atomic state. With the transitional helpers gone the
cached value can be used in the scaler, and committed after all
crtc's are disabled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90874Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

All transitional plane helpers are gone, party!
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

By making color key atomic there are no more transitional helpers.
The plane check function will reject the color key when a scaler is
active.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No need to repeatedly call update_watermarks, or update_fbc.
Down to a single call to update_watermarks in .crtc_enable
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Now that all planes are added during a modeset we can use the
calculated changes before disabling a plane, and then either commit
or force disable a plane before disabling the crtc.

The code is shared with atomic_begin/flush, except watermark updating
and vblank evasion are not used.

This is needed for proper atomic suspend/resume support.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90868Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Read out the initial state, and add a quirk to force add all planes
to crtc_state->plane_mask during initial commit. This will disable
all planes during the initial modeset.

The initial plane quirk is temporary, and will go away when hardware
readout is fully atomic, and the watermark updates in intel_sprite.c
are removed.

Changes since v1:
- Unset state->visible on !primary planes.
- Do not rely on the plane->crtc pointer in intel_atomic_plane,
  instead assume planes are invisible until modeset.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

All the checks in intel_modeset_checks are only useful when a modeset
occurs, because there is nothing to update otherwise.

Same for power/cdclk changes, if there is no modeset they are noops.

Unfortunately intel_modeset_pipe_config still gets called without
modeset, because atomic hw readout isn't done yet.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

To allow them to be used in intel_set_mode.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is probably intended to be be done during vblank evasion.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The idea was good, but planes can have a fb even though
they're disabled. This makes the force argument useless
and always true, because only the commit function updates
state.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

By passing crtc_state to the check_plane functions a lot of duplicated
code can be removed. There are still some transitional helper calls,
they will be removed later.

Changes since v1:
- Revert state->visible changes.
- Use plane->state->crtc instead of plane->crtc.
- Use drm_atomic_get_existing_crtc_state.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

No point in hiding behind big ifs. This will be true most of the time.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This makes it easier to verify that no changes are done when
calling this from crtc instead.

Changes since v1:
 - Make intel_wm_need_update static and always check it.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

commit 2c310b9d2859863826c3688c88218d607d5dd19a
Author: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Date:   Mon May 18 12:28:52 2015 +0200

drm/i915: Split skl_update_scaler, v4.

It's easier to read separate functions for crtc and plane scaler state.

Changes since v1:
 - Update documentation.
Changes since v2:
 - Get rid of parameters to skl_update_scaler only used for traces.
   This avoids needing to document the other parameters.
Changes since v3:
 - Rename scaler_idx to scaler_user.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

It saves another loop over all crtc's in the state, and computing
clock is more of a per crtc thing.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Tested-by(IVB): Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>