[PATCH 3/4] drm/panfrost: only put powered shader cores in the job affinity

[Young-Jun Hong <nirvanah@nirvanahyj.com>]

On GPUs with more than one L2 (core group), panfrost powers only the
first core group (panfrost_get_core_mask()), but the job affinity is
written from shader_present, i.e. it also names the cores of the second,
unpowered group (Mali-T628 MP6 on Exynos 5422: l2_present 0x11, 4+2
cores, affinity 0x3f while only 0x0f is powered).

Write the affinity from the same mask that was powered, so a job never
names cores that are off.

Tested on Samsung ARTIK 10 (Exynos 5422), Mali-T628 MP6.

The analysis, the code and this changelog were produced with Claude
Code (Anthropic), a coding assistant.

Fixes: 6e55d273708b ("drm/panfrost: initial dual core group GPUs support")
Signed-off-by: Young-Jun Hong <nirvanah@nirvanahyj.com>
---
 drivers/gpu/drm/panfrost/panfrost_gpu.c | 6 ++++++
 drivers/gpu/drm/panfrost/panfrost_gpu.h | 1 +
 drivers/gpu/drm/panfrost/panfrost_job.c | 2 +-
 3 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.c b/drivers/gpu/drm/panfrost/panfrost_gpu.c
index 6081b27829e1..420d224276a5 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.c
@@ -452,6 +452,12 @@ static u64 panfrost_get_core_mask(struct panfrost_device *pfdev)
 	return core_mask;
 }
 
+/* cores that panfrost_gpu_power_on() powers */
+u64 panfrost_powered_core_mask(struct panfrost_device *pfdev)
+{
+	return pfdev->features.shader_present & panfrost_get_core_mask(pfdev);
+}
+
 void panfrost_gpu_power_on(struct panfrost_device *pfdev)
 {
 	int ret;
diff --git a/drivers/gpu/drm/panfrost/panfrost_gpu.h b/drivers/gpu/drm/panfrost/panfrost_gpu.h
index b4fef11211d5..78a6270b7fcb 100644
--- a/drivers/gpu/drm/panfrost/panfrost_gpu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_gpu.h
@@ -13,6 +13,7 @@ void panfrost_gpu_fini(struct panfrost_device *pfdev);
 u32 panfrost_gpu_get_latest_flush_id(struct panfrost_device *pfdev);
 
 int panfrost_gpu_soft_reset(struct panfrost_device *pfdev);
+u64 panfrost_powered_core_mask(struct panfrost_device *pfdev);
 void panfrost_gpu_power_on(struct panfrost_device *pfdev);
 void panfrost_gpu_power_off(struct panfrost_device *pfdev);
 void panfrost_gpu_suspend_irq(struct panfrost_device *pfdev);
diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 4ddf4b722ddf..33da86587db7 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -143,7 +143,7 @@ static void panfrost_job_write_affinity(struct panfrost_device *pfdev,
 	 * Eventually we may need to support tiler only jobs and h/w with
 	 * multiple (2) coherent core groups
 	 */
-	affinity = pfdev->features.shader_present;
+	affinity = panfrost_powered_core_mask(pfdev);
 
 	job_write(pfdev, JS_AFFINITY_NEXT_LO(js), lower_32_bits(affinity));
 	job_write(pfdev, JS_AFFINITY_NEXT_HI(js), upper_32_bits(affinity));
-- 
2.47.3