drm/msm/devfreq: Restrict idle clamping to a618 for now

Until we better understand the stability issues caused by frequent
frequency changes, lets limit them to a618.

Signed-off-by: Rob Clark <robdclark@chromium.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Tested-by: Caleb Connolly <caleb.connolly@linaro.org>
Link: https://lore.kernel.org/r/20211018153627.2787882-1-robdclark@gmail.com
Signed-off-by: Rob Clark <robdclark@chromium.org>
diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 33da25b..267a880 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1838,6 +1838,13 @@
 			adreno_cmp_rev(ADRENO_REV(6, 3, 5, ANY_ID), info->rev)))
 		adreno_gpu->base.hw_apriv = true;
 
+	/*
+	 * For now only clamp to idle freq for devices where this is known not
+	 * to cause power supply issues:
+	 */
+	if (info && (info->revn == 618))
+		gpu->clamp_to_idle = true;
+
 	a6xx_llc_slices_init(pdev, a6xx_gpu);
 
 	ret = a6xx_set_supported_hw(&pdev->dev, config->rev);
diff --git a/drivers/gpu/drm/msm/msm_gpu.h b/drivers/gpu/drm/msm/msm_gpu.h
index 030f82f..ee25d55 100644
--- a/drivers/gpu/drm/msm/msm_gpu.h
+++ b/drivers/gpu/drm/msm/msm_gpu.h
@@ -203,6 +203,10 @@
 	uint32_t suspend_count;
 
 	struct msm_gpu_state *crashstate;
+
+	/* Enable clamping to idle freq when inactive: */
+	bool clamp_to_idle;
+
 	/* True if the hardware supports expanded apriv (a650 and newer) */
 	bool hw_apriv;
 
diff --git a/drivers/gpu/drm/msm/msm_gpu_devfreq.c b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
index 84e98c0..20006d0 100644
--- a/drivers/gpu/drm/msm/msm_gpu_devfreq.c
+++ b/drivers/gpu/drm/msm/msm_gpu_devfreq.c
@@ -200,7 +200,8 @@
 
 	idle_freq = get_freq(gpu);
 
-	msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
+	if (gpu->clamp_to_idle)
+		msm_devfreq_target(&gpu->pdev->dev, &target_freq, 0);
 
 	df->idle_time = ktime_get();
 	df->idle_freq = idle_freq;