The used space in a ring is given by the cyclic distance from the
consumer (HEAD) to the producer (TAIL), i.e. ((tail-head) MOD size);
conversely, the available space in a ring is the cyclic distance
from the producer to the consumer, MINUS the amount reserved for a
"gap" that is supposed to guarantee that the producer never catches
up with or overruns the consumer. Note that some GEN h/w requires
that TAIL never approach to within one cacheline of HEAD, so the gap
is usually set to twice the cacheline size to ensure this.

While the existing code gives the correct answer for correct inputs,
if the producer HAS overrun into the reserved space, the result can
be a value larger than the maximum valid value (size-reserved). We
can improve this by reorganising the calculation, so that in the
event of overrun the result will be negative rather than over-large.

This means that the commonly-used test (available >= required)
will then reject further writes into the ring after an overrun,
giving some chance that we can recover from or at least diagnose
the original problem; whereas allowing more writes would likely both
confuse the h/w and destroy the evidence of what went wrong.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Later on this can include multiple ports (e.g. (1 << PORT_A) | (1 <<
PORT_C)) to describe dual link DSI.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

MIPI DSI works on ports A and C, which map to pipes A and B,
respectively. Things are going to get more complicated with the
introduction of dual link DSI support, so clean up the register defines
and code to match reality.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Gaurav K Singh <gaurav.k.singh@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Clear the video overlay state on GPU reset. Any pending overlay request
in the ring has been nuked, and the display itself gets reset. So we
pretty much lose all state here. Adjust the software state to match so
that the next "putimage" will restore things to working order.

v2: Ass a locking check into intel_overlay_release_old_vid() (Daniel)

Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
[danvet: s/0/NULL/ to appease sparse, reported by 0-day tester.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Updated the trace_irq code to use requests instead of seqnos. This includes
reference counting the request object to ensure it sticks around when required.
Note that getting access to the reference counting functions means moving the
inline i915_trace_irq_get() function from intel_ringbuffer.h to i915_drv.h.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Resolve conflict due to shuffled merge order.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Similar to the patch from John which removed obj->ring.

Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

The ring member of the object structure was always updated with the
last_read_seqno member. Thus with the conversion to last_read_req, obj->ring is
now a direct copy of obj->last_read_req->ring. This makes it somewhat redundant
and potentially misleading (especially as there was no comment to explain its
purpose).

This checkin removes the redundant field. Many uses were simply testing for
non-null to see if the object is active on the GPU. Some of these have been
converted to check 'obj->active' instead. Others (where the last_read_req is
about to be used anyway) have been changed to check obj->last_read_req. The rest
simply pull the ring out from the request structure and proceed as before.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Almost everywhere that caled i915_seqno_passed() was really asking 'has the
given seqno popped out of the hardware yet?'. Thus it had to query the current
hardware seqno and then do a signed delta comparison (which copes with wrapping
around zero but not with seqno values more than 2GB apart, although the latter
is unlikely!).

Now that the majority of seqno instances have been replaced with request
structures, it is possible to convert this test to be request based as well.
There is now a 'i915_gem_request_completed()' function which takes a request and
returns true or false as appropriate. Note that this currently just wraps up the
original _passed() test but a later patch in the series will reduce this to
simply returning a cached internal value, i.e.:
  _completed(req) { return req->completed; }'

This checkin converts almost all _seqno_passed() calls. The only one left is in
the semaphore code which still requires seqnos not request structures.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Drop hunk touching the trace_irq code since I've dropped the
patch which converts that, and resolve resulting conflict.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

It makes a lot more sense (and makes future seqno -> request conversion patches
simpler) to fill in the 'ring' field of the request structure at the point of
creation rather than submission. Given that the request structure is assigned by
ring specific code and thus is locked to a ring from the start, there really is
no reason to defer this assignment.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

More seqno value to request structure conversions. Note, this change temporarily
moves the 'get_seqno()' call inside ring_idle() but this will disappear again in
a later patch when i915_seqno_passed() itself is converted.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

All the code above is now using requests not seqnos so it is possible to convert
the trace functions across. Note that rather than get into problematic reference
counting issues, the trace code only saves the seqno and ring values from the
request structure not the structure pointer itself.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Converted the flip_queued_seqno value to be a request structure as part of the
on going seqno to request changes. This includes reference counting the request
being saved away to ensure it can not be retired and freed while the flip code
is still waiting on it.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Again get rid of the _irq request unref by simply moving that
into the unpin worker. Doesn't matter when we hang onto the request
for a bit longer, and in the unpin worker we already grab the
dev->struct_mutex anyway.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

There is no longer any need to retrieve a seqno value from an i915_add_request()
call. The calling code already knows which request structure is being processed
(it can only be ring->OLR). And as the request itself is now used in preference
to the basic seqno value, the latter is now redundant in this situation.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Now that all code above is using request structures instead of seqno values, it
is possible to convert  __wait_seqno() itself. Internally, it is still calling
i915_seqno_passed(), this will be updated later in the series. This step is just
changing the parameter list and function name.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Converted the mmio_flip 'seqno' value to be a request structure as part of the
on going seqno to request changes. This includes reference counting the request
being saved away to ensure it can not be retired and freed while the flip code
is still waiting on it.

v2: Used the IRQ friendly request dereference call in the notify handler as that
code is called asynchronously without holding any useful mutex locks.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Drop the _irq variant and use the normal reques unref,
wrapped in dev->struct_mutex per the discussion on the m-l.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

With refcounting it looks like you can just drop that refcount, but
that's not really the case. So make sure no one forgets.

Motivated by the unlocked call in the mmio flip code.

Cc: John Harrison <John.C.Harrison@Intel.com>
Cc: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Updated i915_wait_seqno() to take a request structure instead of a seqno value
and renamed it accordingly. Internally, it just pulls the seqno out of the
request and calls on to __wait_seqno() as before. However, all the code further
up the stack is now simplified as it can just pass the request object straight
through without having to peek inside.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Squash in hunk from an earlier patch which was rebased
wrongly.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Converted 'last_flip_req' to be an actual request rather than a seqno value as
part of the on going seqno to request changes. This includes reference counting
the request being saved away to ensure it can not be retired and freed while the
overlay code is still waiting on it.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Updated the _check_olr() function to actually take a request object and compare
it to the OLR rather than extracting seqnos and comparing those.

Note that there is one use case where the request object being processed is no
longer available at that point in the call stack. Hence a temporary copy of the
original function is still present (but called _check_ols() instead). This will
be removed in a subsequent patch.

Also, downgraded a BUG_ON to a WARN_ON as apparently the former is frowned upon
for shipping code.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The OLS value is now obsolete. Exactly the same value is guarateed to be always
available as PLR->seqno. Thus it is safe to remove the OLS completely. And also
to rename the PLR to OLR to keep the 'outstanding lazy ...' naming convention
valid.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Added reference counting of the request structure around __wait_seqno() calls.
This is a precursor to updating the wait code itself to take the request rather
than a seqno. At that point, it would be a Bad Idea for a request object to be
retired and freed while the wait code is still using it.

v3:

Note that even though the mutex lock is held during a call to i915_wait_seqno(),
it is still necessary to explicitly bump the reference count. It appears that
the shrinker can asynchronously retire items even though the mutex is locked.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
[danvet: Remove wrongly squashed hunk which breaks the build.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Convert the throttle code to use the request structure rather than extracting a
ring/seqno pair from it and using those. This is in preparation for
__wait_seqno() becoming __wait_request().

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The object structure contains the last read, write and fenced seqno values for
use in syncrhonisation operations. These have now been replaced with their
request structure counterparts.

Note that to ensure that objects do not end up with dangling pointers, the
assignments of last_*_req include reference count updates. Thus a request cannot
be freed if an object is still hanging on to it for any reason.

v2: Corrected 'last_rendering_' to 'last_read_' in a number of comments that did
not get updated when 'last_rendering_seqno' became 'last_read|write_seqno'
several millenia ago.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Added helper functions for retrieving the ring and seqno entries from a request
structure. This allows the internal workings of the request structure to be
hidden from code that is using these. It also allows for useful
workarounds/debug code to be added as or when necessary.

Note that it is intended that the majority (if not all) uses of the seqno
accessor will disappear eventually as code is updated to use the request
structure itself rather than working with seqno values.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The plan is to use request structures everywhere that seqno values were
previously used. This means saving pointers to structures in places that used to
be simple integers. In turn, that means that the target structure now needs much
more stringent lifetime tracking. That is, it must not be freed while some other
random object still holds a pointer to it.

To achieve this tracking, a reference count needs to be added. Whenever a
pointer to the structure is saved away, the count must be incremented and the
free must only occur when all references have been released.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The aim is to replace seqno values with request structures. A step along the way
is to switch to using the PLR in preference to the OLS. That requires the PLR to
only be valid when and only when the OLS is also valid. I.e., the two must be
kept in lock step. Then, code which was using the OLS can be safely switched
over to using the PLR instead.

For: VIZ-4377
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Thomas Daniel <Thomas.Daniel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

That's the version actually taking the dev_priv->power_domains lock.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Before suspending, we wait upon the outstanding GPU requests and flush
our pending idle handlers. This should downclock the GPU to its lowest
power state. Add a WARN to check that the delayed tasks were run and did
their job properly.
Suggested-by: Akash Goel <akash.goel@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Now unused.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

The logical ring code was updating the software ring 'head' value
by reading the hardware 'HEAD' register. In LRC mode, this is not
valid as the hardware is not necessarily executing the same context
that is being processed by the software. Thus reading the h/w HEAD
could put an unrelated (undefined, effectively random) value into
the s/w 'head' -- A Bad Thing for the free space calculations.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The request queue is per-engine, and may therefore contain requests
from several different contexts/ringbuffers. In determining which
request to wait for, this function should only consider requests
from the ringbuffer that it's checking for space, and ignore any
that it finds that belong to other contexts.
Signed-off-by: Dave Gordon <david.s.gordon@intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This patch is the last in series of VLV/CHV PSR,
that finally enable PSR by adding it to HAS_PSR
and calling the proper enable and disable
functions on the right places.

Although it is still disabled by default.

v2: Rebase over intel_psr and merge Durgadoss's fixes.
v3: Fix typo.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Add debugfs support for Valleyview and Cherryview considering that
we have PSR per pipe and  we don't have any kind of
performance counter as we have on other platforms that support PSR.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This patch introduces exit/activate functions for PSR
on VLV+. Since on VLV+ HW cannot track frame updates and force PSR
exit let's use fully SW tracking available.

v2: Rebase over intel_psr.c;
    Remove Single Frame update transitioning from state 3 to 5 directly;
    Fake a software invalidation for sprites and cursor so we don't miss
    any screen update;

v3: As pointed out by Durgadoss msecs_to_jiffies used on wait_for only uses int,
    so let's use 1 instead. Althought the 1/4 of this is needed for the
    transition let's use 1 for simplicity;
    Also fix comments as suggested by Durgadoss

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

The biggest difference from HSW/BDW PSR here is that VLV enable_source
function enables PSR but let it in Inactive state. So it might be called
on early stage along with setup and enable_sink ones.

v2: Rebase over intel_psr.c;
    Remove docs from static functions;
    Merge vlv_psr_active_on_pipe;
    Timeout for psr transition is 250us;
    Remove SRC_TRASMITTER_STATE;

v3: Rebase after is_psr_enabled function got removed;
    Get SRC_TRANSMITTER_STATE back to be on the safe side since
    default for panels is to require link training on exit when
    main link off;
    As pointed out by Durgadoss msecs_to_jiffies used on wait_for only uses int,
    so let's use 1 instead. Althought the 1/4 of this is needed for the
    transition let's use 1 for simplicity;

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Baytrail (Valleyview) and Braswell (Cherryview) uses a complete different
implementation of PSR that we currently have supported for
Haswell and Broadwell. So let's start by adding registers definitions.

I usually don't like commit that adds just registers without using,
but after I put all in one commit I realized that no one would want
to take the AR to review it so I decided to split in order to make
reviewer's life easier. Only last commit in this series will actually
enable the PSR on intel enable panel path.

But as it happens currently with HSW/BDW the plan is to let it
disabled by default (protected by kernel parameter)
while we are able to fully validate it.

v2: Remove a unused bit definition that isn't used on vlv and
    reserved on chv as pointed out by Durgadoss.

Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

This function was in use to check if PSR feature got enabled.
However on HSW and BDW we currently force psr exit by disabling
EDP_PSR_ENABLE bit at EDP_PSR_CTL(dev). So this function was actually
returning the active/inactive state that is different from the enable/disable
meaning and had the risk of false negative.

But anyway this check with DRRS was dangerous, since DRRS could try to get enabled
before PSR gets there. So let's just remove it for now.
A proper synchronization mechanism must be implemented later probably
using pipe config.

Cc: Daniel Vetter <daniel@ffwll.ch>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Single frame update is a feature available on BDW for PSR that allows
Source to send Sink only one frame and get it updated. Usually useful
when page flipping. However with our frontbuffer tracking where we force
psr exit on flips we don't need this feature.

Also after it got added here many workaround was added to documentation
to mask some bits when using single frame update. So the safest thing
is to just stop using it.

v2: Rebase after removing skip aux one and fixing typo on commit message.
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

OEMs can specify if full_link might be always enabled, i.e. only_standby
over VBT.
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

Let's use VBT + 1 now we parse it.

v2: fix subject

v3: rebase over intel_psr and without counting on previous fix

Cc: Arthur Runyan <arthur.j.runyan@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>