[PATCH] drm/etnaviv: fix external abort seen on GC600 rev 0x19

[Christian Gmeiner]

It looks like that this GPU core triggers an abort when
reading VIVS_HI_CHIP_PRODUCT_ID and/or VIVS_HI_CHIP_CUSTOMER_ID.

I looked at different versions of Vivante's kernel driver and did
not found anything about this issue or what feature flag can be
used. So go the simplest route and do not read these two registers
on the affected GPU core.

Signed-off-by: Christian Gmeiner <christian.gmeiner at gmail.com>
Reported-by: Josua Mayer <josua.mayer at jm0.eu>
Fixes: 815e45bbd4d3 ("drm/etnaviv: determine product, customer and eco id")
Cc: stable at vger.kernel.org
---
 drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index d5a4cd85a0f6..d3906688c2b3 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -337,10 +337,17 @@ static void etnaviv_hw_identify(struct etnaviv_gpu *gpu)
 
 		gpu->identity.model = gpu_read(gpu, VIVS_HI_CHIP_MODEL);
 		gpu->identity.revision = gpu_read(gpu, VIVS_HI_CHIP_REV);
-		gpu->identity.product_id = gpu_read(gpu, VIVS_HI_CHIP_PRODUCT_ID);
-		gpu->identity.customer_id = gpu_read(gpu, VIVS_HI_CHIP_CUSTOMER_ID);
 		gpu->identity.eco_id = gpu_read(gpu, VIVS_HI_CHIP_ECO_ID);
 
+		/*
+		 * Reading these two registers on GC600 rev 0x19 result in a
+		 * unhandled fault: external abort on non-linefetch
+		 */
+		if (!etnaviv_is_model_rev(gpu, GC600, 0x19)) {
+			gpu->identity.product_id = gpu_read(gpu, VIVS_HI_CHIP_PRODUCT_ID);
+			gpu->identity.customer_id = gpu_read(gpu, VIVS_HI_CHIP_CUSTOMER_ID);
+		}
+
 		/*
 		 * !!!! HACK ALERT !!!!
 		 * Because people change device IDs without letting software
-- 
2.26.2