drm/i915/gt: Select the deepest available parking mode for rc6

On Ivybridge, we can go lower than rc6 to rc6p. And this is required for
Ivybridge to hit the same minimum power consumption as rc6 on other
platforms, so make it so.

v2: Update selftest to include all rc6 residency counters

Note that Andi did mention that we should be converting the magic
numbers into opaque magic macros, so if they ever get reused (unlikely
given only Ivybridge used the extra modes) we'll need to pay back the
technical debt.

Closes: https://gitlab.freedesktop.org/drm/intel/issues/1518
Fixes: 730eaeb ("drm/i915/gt: Manual rc6 entry upon parking")
Testcase: igt/i915_pm_rc6_residency/rc6-idle
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200324134232.8773-1-chris@chris-wilson.co.uk
(cherry picked from commit 13c5a57)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

drivers/gpu/drm/i915/gt/intel_rc6.c

@@ -603,6 +603,7 @@ void intel_rc6_unpark(struct intel_rc6 *rc6)
 void intel_rc6_park(struct intel_rc6 *rc6)
 {
 	struct intel_uncore *uncore = rc6_to_uncore(rc6);
+	unsigned int target;
 
 	if (!rc6->enabled)
 		return;
@@ -617,7 +618,14 @@ void intel_rc6_park(struct intel_rc6 *rc6)
 
 	/* Turn off the HW timers and go directly to rc6 */
 	set(uncore, GEN6_RC_CONTROL, GEN6_RC_CTL_RC6_ENABLE);
-	set(uncore, GEN6_RC_STATE, 0x4 << RC_SW_TARGET_STATE_SHIFT);
+
+	if (HAS_RC6pp(rc6_to_i915(rc6)))
+		target = 0x6; /* deepest rc6 */
+	else if (HAS_RC6p(rc6_to_i915(rc6)))
+		target = 0x5; /* deep rc6 */
+	else
+		target = 0x4; /* normal rc6 */
+	set(uncore, GEN6_RC_STATE, target << RC_SW_TARGET_STATE_SHIFT);
 }
 
 void intel_rc6_disable(struct intel_rc6 *rc6)

drivers/gpu/drm/i915/gt/selftest_rc6.c

@@ -12,6 +12,21 @@
 
 #include "selftests/i915_random.h"
 
+static u64 rc6_residency(struct intel_rc6 *rc6)
+{
+	u64 result;
+
+	/* XXX VLV_GT_MEDIA_RC6? */
+
+	result = intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6);
+	if (HAS_RC6p(rc6_to_i915(rc6)))
+		result += intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6p);
+	if (HAS_RC6pp(rc6_to_i915(rc6)))
+		result += intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6pp);
+
+	return result;
+}
+
 int live_rc6_manual(void *arg)
 {
 	struct intel_gt *gt = arg;
@@ -38,9 +53,9 @@ int live_rc6_manual(void *arg)
 	__intel_rc6_disable(rc6);
 	msleep(1); /* wakeup is not immediate, takes about 100us on icl */
 
-	res[0] = intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6);
+	res[0] = rc6_residency(rc6);
 	msleep(250);
-	res[1] = intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6);
+	res[1] = rc6_residency(rc6);
 	if ((res[1] - res[0]) >> 10) {
 		pr_err("RC6 residency increased by %lldus while disabled for 250ms!\n",
 		       (res[1] - res[0]) >> 10);
@@ -51,9 +66,9 @@ int live_rc6_manual(void *arg)
 	/* Manually enter RC6 */
 	intel_rc6_park(rc6);
 
-	res[0] = intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6);
+	res[0] = rc6_residency(rc6);
 	msleep(100);
-	res[1] = intel_rc6_residency_ns(rc6, GEN6_GT_GFX_RC6);
+	res[1] = rc6_residency(rc6);
 
 	if (res[1] == res[0]) {
 		pr_err("Did not enter RC6! RC6_STATE=%08x, RC6_CONTROL=%08x, residency=%lld\n",