[PATCH 10/14] drm/i915/guc/slpc: Enable ARAT timer interrupt

[Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>]

This interrupt is enabled during RPS initialization, and
now needs to be done by SLPC code. It allows ARAT timer
expiry interrupts to get forwarded to GuC.

v2: Fix comment (Matthew Brost)

Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 17 +++++++++++++++++
 drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h |  2 ++
 drivers/gpu/drm/i915/gt/uc/intel_uc.c       |  8 ++++++++
 3 files changed, 27 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
index 2643d207009b..742918875593 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
@@ -403,6 +403,21 @@ int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val)
 	return ret;
 }
 
+void intel_guc_pm_intrmsk_enable(struct intel_gt *gt)
+{
+	u32 pm_intrmsk_mbz = 0;
+
+	/*
+	 * Allow GuC to receive ARAT timer expiry event.
+	 * This interrupt register is setup by RPS code
+	 * when host based Turbo is enabled.
+	 */
+	pm_intrmsk_mbz |= ARAT_EXPIRED_INTRMSK;
+
+	intel_uncore_rmw(gt->uncore,
+			   GEN6_PMINTRMSK, pm_intrmsk_mbz, 0);
+}
+
 /*
  * intel_guc_slpc_enable() - Start SLPC
  * @slpc: pointer to intel_guc_slpc.
@@ -436,6 +451,8 @@ int intel_guc_slpc_enable(struct intel_guc_slpc *slpc)
 	if (unlikely(ret < 0))
 		return ret;
 
+	intel_guc_pm_intrmsk_enable(&i915->gt);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
index 3ffd4f2e3151..e45054d5b9b4 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.h
@@ -9,6 +9,7 @@
 #include "intel_guc_submission.h"
 #include "intel_guc_slpc_types.h"
 
+struct intel_gt;
 struct drm_printer;
 
 static inline bool intel_guc_slpc_is_supported(struct intel_guc *guc)
@@ -36,5 +37,6 @@ int intel_guc_slpc_set_min_freq(struct intel_guc_slpc *slpc, u32 val);
 int intel_guc_slpc_get_max_freq(struct intel_guc_slpc *slpc, u32 *val);
 int intel_guc_slpc_get_min_freq(struct intel_guc_slpc *slpc, u32 *val);
 int intel_guc_slpc_print_info(struct intel_guc_slpc *slpc, struct drm_printer *p);
+void intel_guc_pm_intrmsk_enable(struct intel_gt *gt);
 
 #endif
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index 3e0cd1f05e3b..b104fb7607eb 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -655,6 +655,7 @@ void intel_uc_suspend(struct intel_uc *uc)
 static int __uc_resume(struct intel_uc *uc, bool enable_communication)
 {
 	struct intel_guc *guc = &uc->guc;
+	struct intel_gt *gt = guc_to_gt(guc);
 	int err;
 
 	if (!intel_guc_is_fw_running(guc))
@@ -666,6 +667,13 @@ static int __uc_resume(struct intel_uc *uc, bool enable_communication)
 	if (enable_communication)
 		guc_enable_communication(guc);
 
+	/* If we are only resuming GuC communication but not reloading
+	 * GuC, we need to ensure the ARAT timer interrupt is enabled
+	 * again. In case of GuC reload, it is enabled during SLPC enable.
+	 */
+	if (enable_communication && intel_uc_uses_guc_slpc(uc))
+		intel_guc_pm_intrmsk_enable(gt);
+
 	err = intel_guc_resume(guc);
 	if (err) {
 		DRM_DEBUG_DRIVER("Failed to resume GuC, err=%d", err);
-- 
2.25.0