[PATCH v2 4/8] drm/panfrost: Handle error when allocating AS number

[Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>]

If we reach the beginning of the LRU AS list, then return an error.

Signed-off-by: Adrián Larumbe <adrian.larumbe@xxxxxxxxxxxxx>
---
 drivers/gpu/drm/panfrost/panfrost_job.c     | 6 +++++-
 drivers/gpu/drm/panfrost/panfrost_mmu.c     | 5 +++--
 drivers/gpu/drm/panfrost/panfrost_mmu.h     | 2 +-
 drivers/gpu/drm/panfrost/panfrost_perfcnt.c | 9 ++++++++-
 4 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panfrost/panfrost_job.c b/drivers/gpu/drm/panfrost/panfrost_job.c
index 3f4f0682d69d..fba1a376f593 100644
--- a/drivers/gpu/drm/panfrost/panfrost_job.c
+++ b/drivers/gpu/drm/panfrost/panfrost_job.c
@@ -214,7 +214,11 @@ static int panfrost_job_hw_submit(struct panfrost_job *job, int js)
 		goto err_hwsubmit;
 	}
 
-	cfg = panfrost_mmu_as_get(pfdev, job->mmu);
+	ret = panfrost_mmu_as_get(pfdev, job->mmu);
+	if (ret < 0)
+		goto err_hwsubmit;
+
+	cfg = (u32)ret;
 
 	job_write(pfdev, JS_HEAD_NEXT_LO(js), lower_32_bits(jc_head));
 	job_write(pfdev, JS_HEAD_NEXT_HI(js), upper_32_bits(jc_head));
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c
index 2189e42d2bfa..03ac527b35e7 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -155,7 +155,7 @@ static void panfrost_mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
 	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
 }
 
-u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
+int panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
 {
 	int as;
 
@@ -197,7 +197,8 @@ u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
 			if (!atomic_read(&lru_mmu->as_count))
 				break;
 		}
-		WARN_ON(&lru_mmu->list == &pfdev->as_lru_list);
+		if (WARN_ON(&lru_mmu->list == &pfdev->as_lru_list))
+			return -EBUSY;
 
 		list_del_init(&lru_mmu->list);
 		as = lru_mmu->as;
diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.h b/drivers/gpu/drm/panfrost/panfrost_mmu.h
index 022a9a74a114..e6e6966a0cca 100644
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.h
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.h
@@ -16,7 +16,7 @@ void panfrost_mmu_fini(struct panfrost_device *pfdev);
 void panfrost_mmu_reset(struct panfrost_device *pfdev);
 void panfrost_mmu_suspend_irq(struct panfrost_device *pfdev);
 
-u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
+int panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
 void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu *mmu);
 
 struct panfrost_mmu *panfrost_mmu_ctx_get(struct panfrost_mmu *mmu);
diff --git a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
index f30817bcf8ba..2145f9707dde 100644
--- a/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
+++ b/drivers/gpu/drm/panfrost/panfrost_perfcnt.c
@@ -130,7 +130,12 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
 
 	perfcnt->user = user;
 
-	as = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
+	ret = panfrost_mmu_as_get(pfdev, perfcnt->mapping->mmu);
+	if (ret)
+		goto err_unsetuser;
+
+	as = (u32)ret;
+
 	cfg = GPU_PERFCNT_CFG_AS(as) |
 	      GPU_PERFCNT_CFG_MODE(GPU_PERFCNT_CFG_MODE_MANUAL);
 
@@ -164,6 +169,8 @@ static int panfrost_perfcnt_enable_locked(struct panfrost_device *pfdev,
 
 	return 0;
 
+err_unsetuser:
+	perfcnt->user = NULL;
 err_vunmap:
 	drm_gem_vunmap_unlocked(&bo->base, &map);
 err_put_mapping:
-- 
2.47.0