drm/i915: Support for GuC interrupts

There are certain types of interrupts which Host can receive from GuC.
GuC ukernel sends an interrupt to Host for certain events, like for
example retrieve/consume the logs generated by ukernel.
This patch adds support to receive interrupts from GuC but currently
enables & partially handles only the interrupt sent by GuC ukernel.
Future patches will add support for handling other interrupt types.

v2:
- Use common low level routines for PM IER/IIR programming (Chris)
- Rename interrupt functions to gen9_xxx from gen8_xxx (Chris)
- Replace disabling of wake ref asserts with rpm get/put (Chris)

v3:
- Update comments for more clarity. (Tvrtko)
- Remove the masking of GuC interrupt, which was kept masked till the
  start of bottom half, its not really needed as there is only a
  single instance of work item & wq is ordered. (Tvrtko)

v4:
- Rebase.
- Rename guc_events to pm_guc_events so as to be indicative of the
  register/control block it is associated with. (Chris)
- Add handling for back to back log buffer flush interrupts.

v5:
- Move the read & clearing of register, containing Guc2Host message
  bits, outside the irq spinlock. (Tvrtko)

v6:
- Move the log buffer flush interrupt related stuff to the following
  patch so as to do only generic bits in this patch. (Tvrtko)
- Rebase.

v7:
- Remove the interrupts_enabled check from gen9_guc_irq_handler, want to
  process that last interrupt also before disabling the interrupt, sync
  against the work queued by irq handler will be done by caller disabling
  the interrupt.

Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_guc_loader.c b/drivers/gpu/drm/i915/intel_guc_loader.c
index a75abb8..1aa8523 100644
--- a/drivers/gpu/drm/i915/intel_guc_loader.c
+++ b/drivers/gpu/drm/i915/intel_guc_loader.c
@@ -485,6 +485,7 @@ int intel_guc_setup(struct drm_device *dev)
 	}
 
 	guc_interrupts_release(dev_priv);
+	gen9_reset_guc_interrupts(dev_priv);
 
 	guc_fw->guc_fw_load_status = GUC_FIRMWARE_PENDING;
 
@@ -529,6 +530,9 @@ int intel_guc_setup(struct drm_device *dev)
 		intel_guc_fw_status_repr(guc_fw->guc_fw_load_status));
 
 	if (i915.enable_guc_submission) {
+		if (i915.guc_log_level >= 0)
+			gen9_enable_guc_interrupts(dev_priv);
+
 		err = i915_guc_submission_enable(dev_priv);
 		if (err)
 			goto fail;