drm/amdgpu: revert context to stop engine before mode2 reset

For some hang caused by slow tests, engine cannot be stopped which
may cause resume failure after reset. In this case, force halt
engine by reverting context addresses

Signed-off-by: Victor Zhao <[e-mail]>
Acked-by: Andrey Grodzovsky <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 
 			/* set guilty */
 			drm_sched_increase_karma(s_job);
+			amdgpu_reset_prepare_hwcontext(adev, reset_context);
 retry:
 			/* do hw reset */
 			if (amdgpu_sriov_vf(adev)) {

drivers/gpu/drm/amd/amdgpu/amdgpu_gfxhub.h

···
 	void (*utcl2_harvest)(struct amdgpu_device *adev);
 	void (*mode2_save_regs)(struct amdgpu_device *adev);
 	void (*mode2_restore_regs)(struct amdgpu_device *adev);
+	void (*halt)(struct amdgpu_device *adev);
 };
 
 struct amdgpu_gfxhub {

drivers/gpu/drm/amd/amdgpu/gfxhub_v2_1.c

···
 	WREG32_SOC15(GC, 0, mmGCMC_VM_MX_L1_TLB_CNTL, adev->gmc.MC_VM_MX_L1_TLB_CNTL);
 }
 
+static void gfxhub_v2_1_halt(struct amdgpu_device *adev)
+{
+	struct amdgpu_vmhub *hub = &adev->vmhub[AMDGPU_GFXHUB_0];
+	int i;
+	uint32_t tmp;
+	int time = 1000;
+
+	gfxhub_v2_1_set_fault_enable_default(adev, false);
+
+	for (i = 0; i <= 14; i++) {
+		WREG32_SOC15_OFFSET(GC, 0, mmGCVM_CONTEXT1_PAGE_TABLE_START_ADDR_LO32,
+				    i * hub->ctx_addr_distance, ~0);
+		WREG32_SOC15_OFFSET(GC, 0, mmGCVM_CONTEXT1_PAGE_TABLE_START_ADDR_HI32,
+				    i * hub->ctx_addr_distance, ~0);
+		WREG32_SOC15_OFFSET(GC, 0, mmGCVM_CONTEXT1_PAGE_TABLE_END_ADDR_LO32,
+				    i * hub->ctx_addr_distance,
+				    0);
+		WREG32_SOC15_OFFSET(GC, 0, mmGCVM_CONTEXT1_PAGE_TABLE_END_ADDR_HI32,
+				    i * hub->ctx_addr_distance,
+				    0);
+	}
+	tmp = RREG32_SOC15(GC, 0, mmGRBM_STATUS2);
+	while ((tmp & (GRBM_STATUS2__EA_BUSY_MASK |
+		      GRBM_STATUS2__EA_LINK_BUSY_MASK)) != 0 &&
+	       time) {
+		udelay(100);
+		time--;
+		tmp = RREG32_SOC15(GC, 0, mmGRBM_STATUS2);
+	}
+
+	if (!time) {
+		DRM_WARN("failed to wait for GRBM(EA) idle\n");
+	}
+}
+
 const struct amdgpu_gfxhub_funcs gfxhub_v2_1_funcs = {
 	.get_fb_location = gfxhub_v2_1_get_fb_location,
 	.get_mc_fb_offset = gfxhub_v2_1_get_mc_fb_offset,
···
 	.utcl2_harvest = gfxhub_v2_1_utcl2_harvest,
 	.mode2_save_regs = gfxhub_v2_1_save_regs,
 	.mode2_restore_regs = gfxhub_v2_1_restore_regs,
+	.halt = gfxhub_v2_1_halt,
 };

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

···
 	if (!amdgpu_sriov_vf(adev)) {
 		if (adev->gfxhub.funcs->mode2_save_regs)
 			adev->gfxhub.funcs->mode2_save_regs(adev);
+		if (adev->gfxhub.funcs->halt)
+			adev->gfxhub.funcs->halt(adev);
 		r = sienna_cichlid_mode2_suspend_ip(adev);
 	}