We can choose to leave the display PHY CL2 powerdown up to some hardware
signals, or we can force it. The BXT code forces the nonexistent CL2 in
the x1 PHY to power down. Follow suit on CHV. Maybe it can still save
some extra power by disabling some extra logic in CL1, or something.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

CHV has supports some form of automagic clock gating for the
DPIO SUS clock. We can simply enable the magic bits and the
hardware should take care of the rest.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With DPIO powergating active the DPLL can't be accessed unless
something else is keeping the common lane in the channel on.
That means the PPS kick procedure could fail to enable the PLL.

Power up some data lanes to force the common lane to power up
so that the PLL can be enabled temporarily.

v2: Avoid gcc uninitilized variable warning
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Normmally the common lane in a PHY channel gets powered up when some
of the data lanes get powered up. But when we're driving port B with
pipe B we don't want to enabled any of the data lanes, and just want
the DPLL in the common lane to be active.

To make that happens we have to temporarily enable some data lanes
after which we can access the DPLL registers in the common lane. Once
the pipe is up and running we can drop the power override on the data
lanes allowing them to shut down. From this point forward the common
lane will in fact stay powered on until the data lanes in the other
channel get powered down.

Ville's extended explanation from the review thread:

On Wed, Aug 19, 2015 at 07:47:41AM +0530, Deepak wrote:
> One Q, why only for port B? Port C is also in same common lane right?

Port B is in the first PHY channel which also houses CL1. CL1 always
powers up whenever any lanes in either PHY channel are powered up.
CL2 only powers up if lanes in the second channel (ie. the one with
port C) powers up.

So in this scenario (pipe B->port B) we want the DPLL from CL2, but
ideally we only want to power up the lanes for port B. Powering up
port B lanes will only power up CL1, but as we need CL2 instead we
need to, temporarily, power up some lanes in port C as well.

Crossing the streams the other way (pipe A->port C) is not a problem
since CL1 powers up whenever anything else powers up. So powering up
some port C lanes is enough on its own to make the CL1 DPLL
operational, even though CL1 and the lanes live in separate channels.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
[danvet: Amend commit message with extended explanation.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Powergate the PHY lanes when they're not needed. For HDMI all four lanes
are needed always, but for DP we can enable only the needed lanes. To
power down the unused lanes we use some power down override bits in the
DISPLAY_PHY_CONTROL register. Without the overrides it appears that the
hardware always powers on all the lanes. When the port is disabled the
power down override is not needed and the lanes will shut off on their
own. That also means the override is critical to actually be able to
access the DPIO registers before the port is actually enabled.

Additionally the common lanes will power down when not needed. CL1
remains on as long as anything else is on, CL2 will shut down when
all the lanes in the same channel will shut down. There is one exception
for CL2 that will be dealt in a separate patch for clarity.

With potentially some lanes powered down, the DP code now has to check
the number of active lanes before accessing PCS/TX registers. All
registers in powered down blocks will reads as 0xffffffff, and soe we
would drown in warnings from vlv_dpio_read() if we allowed the code
to access all those registers.

Another important detail in the DP code is the "TX latency optimal"
setting. Normally the second TX lane acts as some kind of reset master,
with the other lanes as slaves. But when only a single lane is enabled,
that single lane obviously has to be the master.

A bit of extra care is needed to reconstruct the initial state of the
DISPLAY_PHY_CONTROL register since it can't be read safely. So instead
read the actual lane status from the DPLL/PHY_STATUS registers and
use that to determine which lanes ought to be powergated initially.

We also need to switch the PHY power modes to "deep PSR" to avoid
a hard system hang when powering down the single channel PHY.

Also sprinkle a few debug prints around so that we can monitor the
DISPLAY_PHY_STATUS changes without having to read it and risk
corrupting it.

v2: Add locking to chv_powergate_phy_lanes()
v3: Actually enable dynamic powerdown in the PHY and deal with the
    fallout
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Bunch of stuff needs the DPLL ref/cri clocks on both VLV and CHV,
and having VGA mode enabled causes some problems for CHV. So let's just
pull the code to configure those bits into the disp2d well enable hook.
With the DPLL disable code also fixed to leave those bits alone we
should now have a consistent DPLL state all the time even if the DPLL
is disabled.

This also neatly removes some duplicated code between the VLV and
CHV codepaths.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Most of our char* arrays are markes as const already, but a few slipped
through the cracks. Fix it.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

A couple of hand rolled ARRAY_SIZE()s caught my eye. Get rid of them.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Simple one:
drivers/gpu/drm/i915/i915_debugfs.c:2449:57: warning: Using plain integer as NULL pointer

And something a bit more peculiar:
drivers/gpu/drm/i915/i915_debugfs.c:4953:18: warning: Variable length array is used.
drivers/gpu/drm/i915/i915_debugfs.c:4953:32: warning: Variable length array is used.

We pass a 'const int' as the array size which results in the warning,
dropping the const gets rid of the warning. Weird, but I think getting
rid of the warnings is better than holding on to the const.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

BXT platform uses live status bits from 0x44440 register to obtain DP
status on hotplug. The existing g4x_digital_port_connected() uses a
different register and hence misses DP hotplug events on BXT
platform. This patch fixes it by using the appropriate register(0x44440)
and live status bits(3:5).

Based on a patch by Durgadoss R <durgadoss.r@intel.com>, from whom the
commit message is shamelessly copy pasted.
Reported-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Choose the right function at the intel_digital_port_connected level.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Choose the right function at the intel_digital_port_connected level.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Add a common intel_digital_port_connected() that splits out to functions
for different platforms. No functional changes.

v2: make the function return a boolean
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With the case added for eDP on port A (always connected from this
function's point of view), we should not be hitting any of the default
cases in ibx_digital_port_connected, so add MISSING_CASE annotation.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

We should not be hitting any of the default cases in
g4x_digital_port_connected, so add MISSING_CASE annotation and return
boolean status. The current behaviour is just cargo culting from the
days of yonder when the display port support was added to i915.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The function can be made static there. No functional changes.
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

It is possible the we request to have a mode that has
higher pixel clock than our HW can support. This patch
checks if requested pixel clock is lower than the one
supported by the HW. The requested mode is discarded
if we cannot support the requested pixel clock.

This patch applies to DVO.

V2:
- removed computation for max pixel clock

V3:
- cleanup by removing unnecessary lines

V4:
- clock check against max dotclock moved inside 'if (fixed_mode)'

V5:
- dot clock check against fixed_mode clock when available
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

It is possible the we request to have a mode that has
higher pixel clock than our HW can support. This patch
checks if requested pixel clock is lower than the one
supported by the HW. The requested mode is discarded
if we cannot support the requested pixel clock.

This patch applies to DSI.

V2:
- removed computation for max pixel clock

V3:
- cleanup by removing unnecessary lines

V4:
- max_pixclk variable renamed as max_dotclk
- moved dot clock checking inside 'if (fixed_mode)'

V5:
- dot clock checked against fixed_mode clock
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

It is possible the we request to have a mode that has
higher pixel clock than our HW can support. This patch
checks if requested pixel clock is lower than the one
supported by the HW. The requested mode is discarded
if we cannot support the requested pixel clock.

This patch applies to LVDS.

V2:
- removed computation for max pixel clock

V3:
- cleanup by removing unnecessary lines

V4:
- moved supported dotclock check from mode_valid() to intel_lvds_init()

V5:
- dotclock check moved back to mode_valid() function
- dotclock check for fixed mode
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Store max dotclock into dev_priv structure so we are able
to filter out the modes that are not supported by our
platforms.

V2:
- limit the max dot clock frequency to max CD clock frequency
  for the gen9 and above
- limit the max dot clock frequency to 90% of the max CD clock
  frequency for the older gens
- for Cherryview the max dot clock frequency is limited to 95%
  of the max CD clock frequency
- for gen2 and gen3 the max dot clock limit is set to 90% of the
  2X max CD clock frequency

V3:
- max_dotclk variable renamed as max_dotclk_freq in i915_drv.h
- in intel_compute_max_dotclk() the rounding method changed from
  round up to round down when computing max dotclock

V4:
- Haswell and Broadwell supports now dot clocks up to max CD clock
  frequency
Signed-off-by: Mika Kahola <mika.kahola@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Add vlv_dport_to_phy() and fix up the return values of
vlv_dport_to_channel() and vlv_pipe_to_channel() to use
the appropriate enums.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With DPIO powergating active on CHV, we can't even access the DPIO PLL
registers until the lane power state overrides have been enabled. That
will happen from the encoder .pre_pll_enable() hook, so move
chv_prepare_pll() to happen after that point, which puts it just before
chv_enable_pll() actually.

Do the same for VLV to avoid accumulating weird differences between the
platforms. Both platforms seem happy with the new arrangement.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

dev_priv->chv_phy_control is protected by the power_domains->lock
elsewhere, so also grab it when initializing chv_phy_control.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

To implement DPIO lane power gating on CHV we're going to need to access
DPIO registers from the cmn power well enable hook. That gets called
rather early, so we need to move the DPIO port IOSF sideband port
assignment earlier as well.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Move the CHV clock buffer disable from chv_disable_pll() to the new
encoder .post_pll_disable() hook. This is more symmetric since the
clock buffer enable happens from the .pre_pll_enable() hook.

We'll have more use for the new hook soon.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The docs give you the impression that the unique transition scale
value shouldn't matter when unique transition scale is enabled. But
as Imre found on BXT (and I verfied also on BSW) the value does
matter. So from now on just program the same value 0x9a always.

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

When fractional m2 divider isn't used on CHV the fractional part
is ignore by the hardware. Despite that, program the fractional
value (0 in this case) to the hardware register just to keep
things a bit more consistent. Might at least make register dumps
a bit less confusing when there isn't some stale fractional part
hanging around.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The current versions of these two macros don't work correctly if the
argument expression happens to contain a modulo operator (%) -- when
stringified, it gets interpreted as a printf formatting character!
With a specifically crafted parameter, this could probably cause a
kernel OOPS; consider WARN_ON(p%s) or WARN_ON(f %*pEp).

Instead, we should use an explicit "%s" format, with the stringified
expression as the coresponding literal-string argument.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With MST there won't be a crtc assigned to the main link encoder, so
trying to dig up the pipe_config from there is a recipe for an oops.

Instead store the parameters (lane_count and link_rate) in the encoder,
and use those values during link training etc. Since those parameters
are now assigned only when the link is actually enabled,
.compute_config() won't clobber them as it did before.

Hardware state readout is still bonkers though as we don't transfer the
link parameters from pipe_config intel_dp. We should do that during
encoder sanitation. But since we don't even do a proper job of reading
out the main link encoder state for MST there's littel point in
worrying about this now.

Fixes a regression with MST caused by:
 commit 90a6b7b0
 Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
 Date:   Mon Jul 6 16:39:15 2015 +0300

    drm/i915: Move intel_dp->lane_count into pipe_config

v2: Different apporoach that should keep intel_dp_check_mst_status()
    somewhat less oopsy

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reported-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Due to a coherency issue on BXT A steppings we can't guarantee a
coherent view of cached (CPU snooped) GPU mappings, so fail such
requests. User space is supposed to fall back to uncached mappings in
this case.

v2:
- limit the WA to A steppings, on later stepping this HW issue is fixed
v3:
- return error instead of trying to work around the issue in kernel,
  since that could confuse user space (Chris)

Testcast: igt/gem_store_dword_batches_loop/cached-mapping
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

By running igt/store_dword_loop_render on BXT we can hit a coherency
problem where the seqno written at GPU command completion time is not
seen by the CPU. This results in __i915_wait_request seeing the stale
seqno and not completing the request (not considering the lost
interrupt/GPU reset mechanism). I also verified that this isn't a case
of a lost interrupt, or that the command didn't complete somehow: when
the coherency issue occured I read the seqno via an uncached GTT mapping
too. While the cached version of the seqno still showed the stale value
the one read via the uncached mapping was the correct one.

Work around this issue by clflushing the corresponding CPU cacheline
following any store of the seqno and preceding any reading of it. When
reading it do this only when the caller expects a coherent view.

v2:
- fix using the proper logical && instead of a bitwise & (Jani, Mika)
- limit the workaround to A stepping, on later steppings this HW issue
  is fixed
v3:
- use a separate get_seqno/set_seqno vfunc (Chris)

Testcase: igt/store_dword_loop_render
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

We also need to call the frontbuffer flip to trigger proper
invalidations when disabling planes. Otherwise we will miss
screen updates when disabling sprites or cursor.

On core platforms where HW tracking also works, this issue
is totally masked because HW tracking triggers PSR exit
however on VLV/CHV that has only SW tracking we miss screen
updates when disabling planes.

It was caught with kms_psr_sink_crc sprite_plane_onoff
and cursor_plane_onoff subtests running on VLV/CHV.

This is probably a regression since I can also get this
with the manual test case, but with so many changes on atomic
modeset I couldn't track exactly when this was introduced.
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

MI_STORE_REGISTER_MEM, MI_LOAD_REGISTER_MEM instructions are not really
variable length instructions unlike MI_LOAD_REGISTER_IMM where it expects
(reg, addr) pairs so use fixed length for these instructions.

v2: rebase

Cc: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
[danvet: Appease checkpatch as Mika spotted in i915_reg.h - it seems
terminally unhappy about i915_cmd_parser.c so that would be a separate
patch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

In commit
 d1675198: drm/i915: Integrate GuC-based command submission

the drm.tmpl include lines reference the intel_guc_submission.c but the
patch adds the file i915_guc_submission.c. drm.tmpl fails to build with:
 docproc: .//drivers/gpu/drm/i915/intel_guc_submission.c:
  No such file or directory

Change the file reference to the actual file.
Signed-off-by: Graham Whaley <graham.whaley@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

There's so much scaler debugging messages that it makes other debugging
hard. Remove them.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This provides a means of reading status and counts relating
to GuC actions and submissions.

v2:
    Remove surplus blank line in output [Chris Wilson]

v5:
    Added GuC per-engine submission & seqno statistics

v6:
    Add per-ring statistics to client, refactor client-dumper.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Alex Dai <yu.dai@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

GuC-based submission is mostly the same as execlist mode, up to
intel_logical_ring_advance_and_submit(), where the context being
dispatched would be added to the execlist queue; at this point
we submit the context to the GuC backend instead.

There are, however, a few other changes also required, notably:
1.  Contexts must be pinned at GGTT addresses accessible by the GuC
    i.e. NOT in the range [0..WOPCM_SIZE), so we have to add the
    PIN_OFFSET_BIAS flag to the relevant GGTT-pinning calls.

2.  The GuC's TLB must be invalidated after a context is pinned at
    a new GGTT address.

3.  GuC firmware uses the one page before Ring Context as shared data.
    Therefore, whenever driver wants to get base address of LRC, we
    will offset one page for it. LRC_PPHWSP_PN is defined as the page
    number of LRCA.

4.  In the work queue used to pass requests to the GuC, the GuC
    firmware requires the ring-tail-offset to be represented as an
    11-bit value, expressed in QWords. Therefore, the ringbuffer
    size must be reduced to the representable range (4 pages).

v2:
    Defer adding #defines until needed [Chris Wilson]
    Rationalise type declarations [Chris Wilson]

v4:
    Squashed kerneldoc patch into here [Daniel Vetter]

v5:
    Update request->tail in code common to both GuC and execlist modes.
    Add a private version of lr_context_update(), as sharing the
        execlist version leads to race conditions when the CPU and
        the GuC both update TAIL in the context image.
    Conversion of error-captured HWS page to string must account
        for offset from start of object to actual HWS (LRC_PPHWSP_PN).

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Turn on interrupt steering to route necessary interrupts to GuC.

v6:
    Rebased

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

A GuC client has its own doorbell and workqueue. It maintains the
doorbell cache line, process description object and work queue item.

A default guc_client is created for the i915 driver to use for
normal-priority in-order submission.

Note that the created client is not yet ready for use; doorbell
allocation will fail as we haven't yet linked the GuC's context
descriptor to the default contexts for each ring (see later patch).

v2:
    Defer adding structure members until needed [Chris Wilson]
    Rationalise type declarations [Chris Wilson]

v5:
    Add GuC per-engine submission & seqno statistics.
    Move wq locking to encompass both get_space() and add_item().
    Take forcewake lock in host2guc_action() [Tom O'Rourke]

v6:
    Fix GuC doorbell cacheline selection code (the
        cacheline-within-page calculation was wrong).
    Rename GuC priorities to make them closer to the names used in
        the GuC firmware source, matching what the autogenerated
        versions will (probably) be.
    Add per-ring statistics to client.

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Allocate a GEM object to hold GuC log data. A debugfs interface
(i915_guc_log_dump) is provided to print out the log content.

v2:
    Add struct members at point of use [Chris Wilson]

v6:
    Rebased

Issue: VIZ-4884
Signed-off-by: Alex Dai <yu.dai@intel.com>
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Tom O'Rourke <Tom.O'Rourke@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>