drm/etnaviv: update MLCG disables with info from newer Vivante driver

PA clock gating can be enabled when the right bugfix bit is present.

There are broken revs of GC4000 and GC2000, which need TX clock gating
to be disabled.
Signed-off-by: Lucas Stach <l.stach@pengutronix.de>

drivers/gpu/drm/etnaviv/etnaviv_gpu.c

@@ -523,9 +523,10 @@ static void etnaviv_gpu_enable_mlcg(struct etnaviv_gpu *gpu)
 
 	pmc = gpu_read(gpu, VIVS_PM_MODULE_CONTROLS);
 
-	/* Disable PA clock gating for GC400+ except for GC420 */
+	/* Disable PA clock gating for GC400+ without bugfix except for GC420 */
 	if (gpu->identity.model >= chipModel_GC400 &&
-	    gpu->identity.model != chipModel_GC420)
+	    gpu->identity.model != chipModel_GC420 &&
+	    !(gpu->identity.minor_features3 & chipMinorFeatures3_BUG_FIXES12))
 		pmc |= VIVS_PM_MODULE_CONTROLS_DISABLE_MODULE_CLOCK_GATING_PA;
 
 	/*
@@ -541,6 +542,11 @@ static void etnaviv_gpu_enable_mlcg(struct etnaviv_gpu *gpu)
 	if (gpu->identity.revision < 0x5422)
 		pmc |= BIT(15); /* Unknown bit */
 
+	/* Disable TX clock gating on affected core revisions. */
+	if (etnaviv_is_model_rev(gpu, GC4000, 0x5222) ||
+	    etnaviv_is_model_rev(gpu, GC2000, 0x5108))
+		pmc |= VIVS_PM_MODULE_CONTROLS_DISABLE_MODULE_CLOCK_GATING_TX;
+
 	pmc |= VIVS_PM_MODULE_CONTROLS_DISABLE_MODULE_CLOCK_GATING_RA_HZ;
 	pmc |= VIVS_PM_MODULE_CONTROLS_DISABLE_MODULE_CLOCK_GATING_RA_EZ;