Positively checking for the required feature/gen is simpler than build
a cascade of negative "we need to bail" checks. And the later won't
scale if we add more stuff that doesn't fit in nicely.
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Dumb binary interfaces which allow root-only updates of the cache
remapping registers. As mentioned in a previous patch, software using
this interface needs to know about HW limits, and other programming
considerations as the kernel interface does no checking for these things
on the root-only interface.

v1: Drop extra posting reads (Chris)
Return negative values in the sysfs interfaces on errors (Chris)

v2: Return -EINVAL for offset % 4 (Jesse)
Move schizo userspace check out (Jesse)
Cleaner sysfs item initializers (Daniel)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Chris' fix for my 32b breakage was incorrect. do_div returns a
remainder. Go back to a divide macro which is more 32b friendly.

Tested on x86-64.

This has only been compile tested on 32b systems.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=48756
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Sincere-apologies: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NBen Widawsky <benjamin.widawsky@intel.com>
[danvet: fixup 32bit compile-fail.]
Signed-Off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Merge rc6 information into the power group for our device. Until now the
i915 driver has not had any sysfs entries (aside from the connector
stuff enabled by drm core). Since it seems like we're likely to have
more in the future I created a new file for sysfs stubs, as well as the
rc6 sysfs functions which don't really belong elsewhere (perhaps
i915_suspend, but most of the stuff is in intel_display,c).

displays rc6 modes enabled (as a hex mask):
cat /sys/class/drm/card0/power/rc6_enable

displays #ms GPU has been in rc6 since boot:
cat /sys/class/drm/card0/power/rc6_residency_ms

displays #ms GPU has been in deep rc6 since boot:
cat /sys/class/drm/card0/power/rc6p_residency_ms

displays #ms GPU has been in deepest rc6 since boot:
cat /sys/class/drm/card0/power/rc6pp_residency_ms

Important note: I've seen on SNB that even when RC6 is *not* enabled the
rc6 register seems to have a random value in it. I can only guess at the
reason reason for this. Those writing tools that utilize this value need
to be careful and probably want to scrutinize the value very carefully.

v2: use common rc6 residency units to milliseconds for the other RC6 types

v3: don't create sysfs files for GEN <= 5
add a rc6_enable to show a mask of enabled rc6 types
use unmerge instead of remove for sysfs group
squash intel_enable_rc6() extraction into this patch

v4: rename sysfs files (Chris)

CC: Chris Wilson <chris@chris-wilson.co.uk>
CC: Daniel Vetter <daniel.vetter@ffwll.ch>f
CC: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NBen Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
[danvet: squash in the 64bit division fix by Chris Wilson.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>