drm/msm/a6xx: restore previous freq on resume

Previously, if the freq were overriden (ie. via sysfs), it would get
reset to max on resume.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>

drivers/gpu/drm/msm/adreno/a6xx_gmu.c

@@ -149,6 +149,8 @@ void a6xx_gmu_set_freq(struct msm_gpu *gpu, unsigned long freq)
 		if (freq == gmu->gpu_freqs[perf_index])
 			break;
 
+	gmu->current_perf_index = perf_index;
+
 	__a6xx_gmu_set_freq(gmu, perf_index);
 }
 
@@ -741,8 +743,8 @@ int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 	gmu_write(gmu, REG_A6XX_GMU_GMU2HOST_INTR_MASK, ~A6XX_HFI_IRQ_MASK);
 	enable_irq(gmu->hfi_irq);
 
-	/* Set the GPU to the highest power frequency */
-	__a6xx_gmu_set_freq(gmu, gmu->nr_gpu_freqs - 1);
+	/* Set the GPU to the current freq */
+	__a6xx_gmu_set_freq(gmu, gmu->current_perf_index);
 
 	/*
 	 * "enable" the GX power domain which won't actually do anything but it
@@ -1166,6 +1168,8 @@ static int a6xx_gmu_pwrlevels_probe(struct a6xx_gmu *gmu)
 	gmu->nr_gpu_freqs = a6xx_gmu_build_freq_table(&gpu->pdev->dev,
 		gmu->gpu_freqs, ARRAY_SIZE(gmu->gpu_freqs));
 
+	gmu->current_perf_index = gmu->nr_gpu_freqs - 1;
+
 	/* Build the list of RPMh votes that we'll send to the GMU */
 	return a6xx_gmu_rpmh_votes_init(gmu);
 }

drivers/gpu/drm/msm/adreno/a6xx_gmu.h

@@ -63,6 +63,9 @@ struct a6xx_gmu {
 	struct clk_bulk_data *clocks;
 	struct clk *core_clk;
 
+	/* current performance index set externally */
+	int current_perf_index;
+
 	int nr_gpu_freqs;
 	unsigned long gpu_freqs[16];
 	u32 gx_arc_votes[16];