[PATCH] drm/etnaviv: disable MLCG and pulse eater on GPU reset

[Lucas Stach]

Module level clock gating and the pulse eater might interfere with
the GPU reset, as they both have the potential to stop the clock
and thus reset propagation to parts of the GPU.

Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
---
I'm not aware of any cases where this would have been an issue, but
it is what the downstream driver does and fundametally seems like
the right thing to do.
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index de8c9894967c..41aab1aa330b 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -505,8 +505,19 @@ static int etnaviv_hw_reset(struct etnaviv_gpu *gpu)
 	timeout = jiffies + msecs_to_jiffies(1000);
 
 	while (time_is_after_jiffies(timeout)) {
-		/* enable clock */
 		unsigned int fscale = 1 << (6 - gpu->freq_scale);
+		u32 pulse_eater = 0x01590880;
+
+		/* disable clock gating */
+		gpu_write_power(gpu, VIVS_PM_POWER_CONTROLS, 0x0);
+
+		/* disable pulse eater */
+		pulse_eater |= BIT(17);
+		gpu_write_power(gpu, VIVS_PM_PULSE_EATER, pulse_eater);
+		pulse_eater |= BIT(0);
+		gpu_write_power(gpu, VIVS_PM_PULSE_EATER, pulse_eater);
+
+		/* enable clock */
 		control = VIVS_HI_CLOCK_CONTROL_FSCALE_VAL(fscale);
 		etnaviv_gpu_load_clock(gpu, control);
 
-- 
2.39.2