Let's take usage of IS_LP to simplify the gem stolen
initialization as suggest by Tvrtko.

Also assume that all new LP platforms follows the chv+
and others bdw+.

v2: Remove the wrong commit message about bxt and glk. (Ander)

Cc: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NAnder Conselvan de Oliveira <conselvan2@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1482174347-24911-1-git-send-email-rodrigo.vivi@intel.com

gen8 is used for both Broadwell and Cherryview but this
function here is only Cherryview and all next atom LP platforms.
So let's rename it to avoid confusion as suggested by Ville.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NAnder Conselvan de Oliveira <conselvan2@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1482096988-400-2-git-send-email-rodrigo.vivi@intel.com

Pineview deserves to use its own platform enum (which was already added,
unused, previously). IS_G33() no longer matches Pineview, and gets
replaced by IS_G33() || IS_PINEVIEW() or equivalent. Pineview is no
longer an outlier among platform definitions.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481143689-19672-1-git-send-email-jani.nikula@intel.com

Consistency FTW.
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/9ab811dc06570bd3fc05a917ade1bdc9bb805a75.1480520526.git.jani.nikula@intel.com

Where it is more appropriate and also to be consistent with
the direction of the driver.

v2: Leave out object alloc/free inlining. (Joonas Lahtinen)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

When gathering the pages from our backing storage we expect get_pages()
to either give us our sg_table or an err ptr. However when gathering our
fake pages for stolen memory we may return NULL in the event of a
failure. To prevent any funny business we should therefore return the
proper err ptr value.

Fixes: 03ac84f1 ("drm/i915: Pass around sg_table to get_pages/put_pages backend")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1479488536-6168-1-git-send-email-matthew.auld@intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

We should never be called via obj->ops->release() on anything other than
a fully formed stolen object, so raise that to an assert. In the process
tidy up a comment and variable no longer used outside of a conditional
BUG.
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20161117155846.4631-1-chris@chris-wilson.co.ukReviewed-by: NMatthew Auld <matthew.auld@intel.com>

We don't spam the debug when we create a normal object, nor when we
allocate their pages. Yet we do for stolen objects, and since these are
quite frequently used (at least once per context), the resulting spam
floods the dmesg in CI.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

And a little bit of cascaded function prototype changes.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

A small selection of macros which can only accept dev_priv from
now on and a resulting trickle of fixups.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>

$ sed -i -r 's/\bglobal_list\b/global_link/g' *.c *.h

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1478081764-8058-1-git-send-email-joonas.lahtinen@linux.intel.com

Unify our approach to things by passing around dev_priv instead of dev.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477946245-14134-22-git-send-email-ville.syrjala@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

The plan is to move obj->pages out from under the struct_mutex into its
own per-object lock. We need to prune any assumption of the struct_mutex
from the get_pages/put_pages backends, and to make it easier we pass
around the sg_table to operate on rather than indirectly via the obj.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-13-chris@chris-wilson.co.uk

The plan is to make obtaining the backing storage for the object avoid
struct_mutex (i.e. use its own locking). The first step is to update the
API so that normal users only call pin/unpin whilst working on the
backing storage.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-12-chris@chris-wilson.co.uk

A while ago we switched from a contiguous array of pages into an sglist,
for that was both more convenient for mapping to hardware and avoided
the requirement for a vmalloc array of pages on every object. However,
certain GEM API calls (like pwrite, pread as well as performing
relocations) do desire access to individual struct pages. A quick hack
was to introduce a cache of the last access such that finding the
following page was quick - this works so long as the caller desired
sequential access. Walking backwards, or multiple callers, still hits a
slow linear search for each page. One solution is to store each
successful lookup in a radix tree.

v2: Rewrite building the radixtree for clarity, hopefully.

v3: Rearrange execbuf to avoid calling i915_gem_object_get_sg() from
within an atomic section and so relax the allocation context to a simple
GFP_KERNEL and mutex.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161028125858.23563-10-chris@chris-wilson.co.uk

Saves 1416 bytes of .rodata strings.

v2: Add parantheses around dev_priv. (Ville Syrjala)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NJani Nikula <jani.nikula@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1476352990-2504-1-git-send-email-tvrtko.ursulin@linux.intel.com

Saves 472 bytes of .rodata strings.

v2: Add parantheses around dev_priv. (Ville Syrjala)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NJani Nikula <jani.nikula@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

Saves 1320 bytes of .rodata strings.

v2: Add parantheses around dev_priv. (Ville Syrjala)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NJani Nikula <jani.nikula@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

Saves 4472 bytes of .rodata strings.

v2: Add parantheses around dev_priv. (Ville Syrjala)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NJani Nikula <jani.nikula@linux.intel.com>
Acked-by: NChris Wilson <chris@chris-wilson.co.uk>
Acked-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>

In an effort to simplify things for a future push of dev_priv instead
of dev wherever possible, always take pdev via dev_priv where
feasible, eliminating the direct access from dev. Right now this
only eliminates a few cases of dev, but it also obviates that we pass
dev into a lot of functions where dev_priv would be the more obvious
choice.

v2: Fixed one more place missing in the previous patch set
Signed-off-by: NDavid Weinehall <david.weinehall@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160822103245.24069-5-david.weinehall@linux.intel.comReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>

In commit 247177dd ("drm/i915: Always set the vma->pages"), as it
title implies, we always set vma->pages for bound objects. Even before
that, we would set vma->ggtt_view.pages, for globally bound objects.
This was forgotten for the fixup inside the preallocated stolen objects,
which has to recreate a global GTT binding outside of the usual VMA
insertion path

Fixes: 247177dd ("drm/i915: Always set the vma->pages")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471430013-3449-1-git-send-email-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Treat the VMA as the primary struct responsible for tracking bindings
into the GPU's VM. That is we want to treat the VMA returned after we
pin an object into the VM as the cookie we hold and eventually release
when unpinning. Doing so eliminates the ambiguity in pinning the object
and then searching for the relevant pin later.

v2: Joonas' stylistic nitpicks, a fun rebase.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471254551-25805-27-git-send-email-chris@chris-wilson.co.uk

Looks like the TSEG lives just above TOUD, stolen comes after TSEG.

The spec seems somewhat self-contradictory in places, in the ESMRAMC
register desctription it says:
 TSEG Size:
  10=(TOUD + 512 KB) to TOUD
  11 =(TOUD + 1 MB) to TOUD

so that agrees with TSEG being at TOUD. But the example given
elsehwere in the spec says:

 TOUD equals 62.5 MB = 03E7FFFFh
 TSEG selected as 512 KB in size,
 Graphics local memory selected as 1 MB in size
 General System RAM available in system = 62.5 MB
 General system RAM range00000000h to 03E7FFFFh
 TSEG address range03F80000h to 03FFFFFFh
 TSEG pre-allocated from03F80000h to 03FFFFFFh
 Graphics local memory pre-allocated from03E80000h to 03F7FFFFh

so here we have TSEG above stolen.

Real world evidence agrees with the TOUD->TSEG->stolen order however, so
let's fix up the code to account for the TSEG size.

Cc: Taketo Kabe <fdporg@vega.pgw.jp>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: stable@vger.kernel.org
Fixes: 0ad98c74 ("drm/i915: Determine the stolen memory base address on gen2")
Fixes: a4dff769 ("x86/gpu: Add Intel graphics stolen memory quirk for gen2 platforms")
Reported-by: NTaketo Kabe <fdporg@vega.pgw.jp>
Tested-by: NTaketo Kabe <fdporg@vega.pgw.jp>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96473Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470653919-27251-1-git-send-email-ville.syrjala@linux.intel.com
Link: http://download.intel.com/design/chipsets/datashts/25251405.pdfReviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

In preparation to perform some magic to speed up i915_vma_pin(), which
is among the hottest of hot paths in execbuf, refactor all the bitfields
accessed by i915_vma_pin() into a single unified set of flags.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470324762-2545-16-git-send-email-chris@chris-wilson.co.uk

When the user closes the context mark it and the dependent address space
as closed. As we use an asynchronous destruct method, this has two
purposes.  First it allows us to flag the closed context and detect
internal errors if we to create any new objects for it (as it is removed
from the user's namespace, these should be internal bugs only). And
secondly, it allows us to immediately reap stale vma.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470293567-10811-27-git-send-email-chris@chris-wilson.co.uk

Since we may have VMA allocated for an object, but we interrupted their
binding, there is a disparity between have elements on the obj->vma_list
and being bound. i915_gem_obj_bound_any() does this check, but this is
not rigorously observed - add an explicit count to make it easier.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470293567-10811-7-git-send-email-chris@chris-wilson.co.uk

Initialising the global GTT is tricky as we wish to use the drm_mm range
manager during the modesetting initialisation (to capture stolen
allocations from the BIOS) before we actually enable GEM. To overcome
this, we currently setup the drm_mm first and then carefully rebind
them.

v2: Fixup after rebasing
v3: GGTT initialisation needs to be split around kicking out conflicts
v4: Restore an old UMS BUG_ON(mappable > total) as a DRM_ERROR plus
fixup of probe results.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1470293567-10811-4-git-send-email-chris@chris-wilson.co.uk

Ultimately wraps kref_put(), so adopt its nomenclature for consistency
with other subsystems.

s/drm_gem_object_unreference/i915_gem_object_put/
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1469005202-9659-6-git-send-email-chris@chris-wilson.co.ukReviewed-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1469017917-15134-5-git-send-email-chris@chris-wilson.co.uk

We need this for kbl a0 boards. Note that this should be also
for bxt A0 but we omit that on purpose as bxt A0's are
out of fashion already.

References: HSD#1912158, HSD#4393097
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-5-git-send-email-mika.kuoppala@intel.com
(cherry picked from commit 6e4f10c3)
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>

Since we now subclass struct drm_device, we can save pointer dances by
noting the equivalence of struct drm_device and struct drm_i915_private,
i.e. by using to_i915().

   text    data     bss     dec     hex filename
1073824    4562     416 1078802  107612 drivers/gpu/drm/i915/i915.ko
1068976    4562     416 1073954  106322 drivers/gpu/drm/i915/i915.ko

Created by the coccinelle script:

@@
expression E;
identifier p;
@@
- struct drm_i915_private *p = E->dev_private;
+ struct drm_i915_private *p = to_i915(E);
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1467628477-25379-1-git-send-email-chris@chris-wilson.co.uk

We need this for kbl a0 boards. Note that this should be also
for bxt A0 but we omit that on purpose as bxt A0's are
out of fashion already.

References: HSD#1912158, HSD#4393097
Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1465309159-30531-5-git-send-email-mika.kuoppala@intel.com

This way optimization from a previous patch works even better.

v2: Rebase.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>

Move the better constructs/comments from i915_gem_stolen.c to
early-quirks.c and increase readability in preparation of only
having one set of functions.

- intel_stolen_base -> gen3_stolen_base
- use phys_addr_t instead of u32 for address for future proofing

v2:
- Print the invalid register values (Chris)
  (Omitting the register prefix as it's visible from backtrace.)

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Acked-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Do not use magic numbers, do not prefix stuff with "PCI_", do not
declare registers in implementation files. Also move the PCI
registers under correct comment in i915_reg.h.

v2:
- Consistently use BSM (not BDSM or other variants from PRM) (Chris)
- Also include register address to help identify the register (Chris)
v3:
- Refer to register value as *_val instead of *_reg (Chris)
v4:
- Make style checker happy

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Refer to the GGTT VM consistently as "ggtt->base" instead of just "ggtt",
"vm" or indirectly through other variables like "dev_priv->ggtt.base"
to avoid confusion with the i915_ggtt object itself and PPGTT VMs.

Refer to the GGTT as "ggtt" instead of indirectly through chaining.

As a bonus gets rid of the long-standing i915_obj_to_ggtt vs.
i915_gem_obj_to_ggtt conflict, due to removal of i915_obj_to_ggtt!

v2:
- Added some more after grepping sources with Chris

v3:
- Refer to GGTT VM through ggtt->base consistently instead of ggtt_vm
  (Chris)

v4:
- Convert all dev_priv->ggtt->foo accesses to ggtt->foo.

v5:
- Make patch checker happy

Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

Refer to Global GTT consistently as GGTT, thus rename dev_priv->gtt
to dev_priv->ggtt and struct i915_gtt to struct i915_ggtt.

Fix a couple of whitespace problems while at it.

v2:
- Fix a typo in commit message.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>

Elsewhere we have adopted the convention of using '_link' to denote
elements in the list (and '_list' for the actual list_head itself), and
that the name should indicate which list the link belongs to (and
preferrably not just where the link is being stored).

s/vma_link/obj_link/ (we iterate over obj->vma_list)
s/mm_list/vm_link/ (we iterate over vm->[in]active_list)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>

VMA creation and GEM list management need the big lock.

v2:

Mutex unlock ended on the wrong path somehow. (0-day, Julia Lawall)

Not to mention drm_gem_object_unreference was there in existing
code with no mutex held.

v3:

Some callers of i915_gem_object_create_stolen_for_preallocated
already hold the lock so move the mutex into the other caller
as well.

v4:

Changed to lockdep_assert_held. (Chris Wilson)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>

RC6 setup is shared between BIOS and Driver. BIOS sets up subset of RC6
setup registers. If those are not setup Driver should not enable RC6.
For implementing this, driver can check RC_CTRL0 and RC_CTRL1 values
to know if BIOS has enabled HW/SW RC6.
This will also enable user to control RC6 using BIOS settings alone.
RC6 related instability can be avoided by disabling via BIOS settings
till driver fixes it.

v2: Had placed logic in gen8 function by mistake. Fixed it.
Ensuring RPM is not enabled in case BIOS disabled RC6.

v3: Need to disable RPM if RC6 is disabled due to BIOS settings. (Daniel)
Runtime PM enabling happens before gen9_enable_rc6.
Moved the updation of enable_rc6 parameter in intel_uncore_sanitize.

v4: Added elaborate check for BIOS RC6 setup. Prepared check_pctx for bxt.
    (Imre)

v5: Caching reserved stolen base and size in the driver private data.
    Reorganized RC6 setup check. Moved from gen9_enable_rc6 to
    intel_uncore_sanitize. (Imre)

v6: Rebasing on the patch submitted by Imre that moves gem_init_stolen
    earlier in the load.

v7: Removed PWRCTX_MAXCNT_VCSUNIT1 check as it applies to SKL. (Imre)

v8: Fixed formatting and checkpatch issues. Fixed functional issue where
    RC6 ctx size check was missing. (Imre)

Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: NSagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: NImre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1454697809-22113-1-git-send-email-sagar.a.kamble@intel.com

i915_gem_object_get_dma_address function is used to retrieve the dma address
of a particular page so as to map it in a given GTT entry for CPU access.
This function would be used for stolen backed objects also for tasks like
pwrite,  clearing of the pages etc. So the obj->get_page.sg needs to be
initialized for the stolen objects also.
Signed-off-by: NAnkitprasad Sharma <ankitprasad.r.sharma@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1450765253-32104-2-git-send-email-ankitprasad.r.sharma@intel.comReviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>