drm/i915: split out uncore_mmio_debug

Multiple uncore structures will share the debug infrastructure, so
move it to a common place and add extra locking around it.
Also, since we now have a separate object, it is cleaner to have
dedicated functions working on the object to stop and restart the
mmio debug. Apart from the cosmetic changes, this patch introduces
2 functional updates:

- All calls to check_for_unclaimed_mmio will now return false when
  the debug is suspended, not just the ones that are active only when
  i915_modparams.mmio_debug is set. If we don't trust the result of the
  check while a user is doing mmio access then we shouldn't attempt the
  check anywhere.

- i915_modparams.mmio_debug is not save/restored anymore around user
  access. The value is now never touched by the kernel while debug is
  disabled so no need for save/restore.

v2: squash mmio_debug patches, restrict mmio_debug lock usage (Chris)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809063116.7527-1-chris@chris-wilson.co.uk

1 files changed, 11 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_uncore.h b/drivers/gpu/drm/i915/intel_uncore.h
index e603d210a34d..414fc2cb0459 100644
--- a/drivers/gpu/drm/i915/intel_uncore.h
+++ b/drivers/gpu/drm/i915/intel_uncore.h
@@ -36,6 +36,13 @@ struct drm_i915_private;
 struct intel_runtime_pm;
 struct intel_uncore;
 
+struct intel_uncore_mmio_debug {
+	spinlock_t lock; /** lock is also taken in irq contexts. */
+	int unclaimed_mmio_check;
+	int saved_mmio_check;
+	u32 suspend_count;
+};
+
 enum forcewake_domain_id {
 	FW_DOMAIN_ID_RENDER = 0,
 	FW_DOMAIN_ID_BLITTER,
@@ -137,14 +144,9 @@ struct intel_uncore {
 		u32 __iomem *reg_ack;
 	} *fw_domain[FW_DOMAIN_ID_COUNT];
 
-	struct {
-		unsigned int count;
-
-		int saved_mmio_check;
-		int saved_mmio_debug;
-	} user_forcewake;
+	unsigned int user_forcewake_count;
 
-	int unclaimed_mmio_check;
+	struct intel_uncore_mmio_debug *debug;
 };
 
 /* Iterate over initialised fw domains */
@@ -179,6 +181,8 @@ intel_uncore_has_fifo(const struct intel_uncore *uncore)
 	return uncore->flags & UNCORE_HAS_FIFO;
 }
 
+void
+intel_uncore_mmio_debug_init_early(struct intel_uncore_mmio_debug *mmio_debug);
 void intel_uncore_init_early(struct intel_uncore *uncore,
 			     struct drm_i915_private *i915);
 int intel_uncore_init_mmio(struct intel_uncore *uncore);