[PATCH v4 3/7] drm/panfrost: Improve error reporting in panfrost_gpu_power_on

[Nicolas Boichat]

It is useful to know which component cannot be powered on.

Signed-off-by: Nicolas Boichat <drinkcat at chromium.org>
Reviewed-by: Steven Price <steven.price at arm.com>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
---

Was useful when trying to probe Bifrost GPU, to understand what
issue we are facing.

v4:
 - No change
v3:
 - Rebased on https://patchwork.kernel.org/patch/11325689/

 drivers/gpu/drm/panfrost/panfrost_gpu.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 460fc190de6e815..856f2fd1fa8ed27 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -308,17 +308,20 @@ void panfrost_gpu_power_on(struct panfrost_device *pfdev)
 	gpu_write(pfdev, L2_PWRON_LO, pfdev->features.l2_present);
 	ret = readl_relaxed_poll_timeout(pfdev->iomem + L2_READY_LO,
 		val, val == pfdev->features.l2_present, 100, 1000);
+	if (ret)
+		dev_err(pfdev->dev, "error powering up gpu L2");
 
 	gpu_write(pfdev, SHADER_PWRON_LO, pfdev->features.shader_present);
-	ret |= readl_relaxed_poll_timeout(pfdev->iomem + SHADER_READY_LO,
+	ret = readl_relaxed_poll_timeout(pfdev->iomem + SHADER_READY_LO,
 		val, val == pfdev->features.shader_present, 100, 1000);
+	if (ret)
+		dev_err(pfdev->dev, "error powering up gpu shader");
 
 	gpu_write(pfdev, TILER_PWRON_LO, pfdev->features.tiler_present);
-	ret |= readl_relaxed_poll_timeout(pfdev->iomem + TILER_READY_LO,
+	ret = readl_relaxed_poll_timeout(pfdev->iomem + TILER_READY_LO,
 		val, val == pfdev->features.tiler_present, 100, 1000);
-
 	if (ret)
-		dev_err(pfdev->dev, "error powering up gpu");
+		dev_err(pfdev->dev, "error powering up gpu tiler");
 }
 
 void panfrost_gpu_power_off(struct panfrost_device *pfdev)
-- 
2.25.0.341.g760bfbb309-goog