drm/amdgpu: Rearm IRQ in Navi10 SR-IOV if IRQ lost

Ported from Vega10. SDMA stress tests sometimes see IRQ lost.
Signed-off-by: Samir Dhume <samir.dhume@amd.com>
Reviewed-by: Monk Liu <monk.liu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/navi10_ih.c

@@ -32,6 +32,7 @@
 #include "soc15_common.h"
 #include "navi10_ih.h"
 
+#define MAX_REARM_RETRY 10
 
 static void navi10_ih_set_interrupt_funcs(struct amdgpu_device *adev);
 
@@ -283,6 +284,38 @@ static void navi10_ih_decode_iv(struct amdgpu_device *adev,
 	ih->rptr += 32;
 }
 
+/**
+ * navi10_ih_irq_rearm - rearm IRQ if lost
+ *
+ * @adev: amdgpu_device pointer
+ *
+ */
+static void navi10_ih_irq_rearm(struct amdgpu_device *adev,
+			       struct amdgpu_ih_ring *ih)
+{
+	uint32_t reg_rptr = 0;
+	uint32_t v = 0;
+	uint32_t i = 0;
+
+	if (ih == &adev->irq.ih)
+		reg_rptr = SOC15_REG_OFFSET(OSSSYS, 0, mmIH_RB_RPTR);
+	else if (ih == &adev->irq.ih1)
+		reg_rptr = SOC15_REG_OFFSET(OSSSYS, 0, mmIH_RB_RPTR_RING1);
+	else if (ih == &adev->irq.ih2)
+		reg_rptr = SOC15_REG_OFFSET(OSSSYS, 0, mmIH_RB_RPTR_RING2);
+	else
+		return;
+
+	/* Rearm IRQ / re-write doorbell if doorbell write is lost */
+	for (i = 0; i < MAX_REARM_RETRY; i++) {
+		v = RREG32_NO_KIQ(reg_rptr);
+		if ((v < ih->ring_size) && (v != ih->rptr))
+			WDOORBELL32(ih->doorbell_index, ih->rptr);
+		else
+			break;
+	}
+}
+
 /**
  * navi10_ih_set_rptr - set the IH ring buffer rptr
  *
@@ -297,6 +330,9 @@ static void navi10_ih_set_rptr(struct amdgpu_device *adev,
 		/* XXX check if swapping is necessary on BE */
 		*ih->rptr_cpu = ih->rptr;
 		WDOORBELL32(ih->doorbell_index, ih->rptr);
+
+		if (amdgpu_sriov_vf(adev))
+			navi10_ih_irq_rearm(adev, ih);
 	} else
 		WREG32_SOC15(OSSSYS, 0, mmIH_RB_RPTR, ih->rptr);
 }