[PATCH v2 3/5] drm/panthor: Ignore devfreq_{suspend, resume}_device() failures

[Boris Brezillon]

devfreq_{resume,suspend}_device() don't bother undoing the suspend_count
modifications if something fails, so either it assumes failures are
harmless, or it's super fragile/buggy. In either case it's not something
we can address at the driver level, so let's just assume failures are
harmless for now, like is done in panfrost.

v2:
- Add R-b

Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
Reviewed-by: Steven Price <steven.price at arm.com>
---
 drivers/gpu/drm/panthor/panthor_devfreq.c | 12 ++++----
 drivers/gpu/drm/panthor/panthor_devfreq.h |  4 +--
 drivers/gpu/drm/panthor/panthor_device.c  | 35 ++---------------------
 3 files changed, 11 insertions(+), 40 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.c b/drivers/gpu/drm/panthor/panthor_devfreq.c
index ecc7a52bd688..3686515d368d 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.c
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.c
@@ -243,26 +243,26 @@ int panthor_devfreq_init(struct panthor_device *ptdev)
 	return 0;
 }
 
-int panthor_devfreq_resume(struct panthor_device *ptdev)
+void panthor_devfreq_resume(struct panthor_device *ptdev)
 {
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 
 	if (!pdevfreq->devfreq)
-		return 0;
+		return;
 
 	panthor_devfreq_reset(pdevfreq);
 
-	return devfreq_resume_device(pdevfreq->devfreq);
+	drm_WARN_ON(&ptdev->base, devfreq_resume_device(pdevfreq->devfreq));
 }
 
-int panthor_devfreq_suspend(struct panthor_device *ptdev)
+void panthor_devfreq_suspend(struct panthor_device *ptdev)
 {
 	struct panthor_devfreq *pdevfreq = ptdev->devfreq;
 
 	if (!pdevfreq->devfreq)
-		return 0;
+		return;
 
-	return devfreq_suspend_device(pdevfreq->devfreq);
+	drm_WARN_ON(&ptdev->base, devfreq_suspend_device(pdevfreq->devfreq));
 }
 
 void panthor_devfreq_record_busy(struct panthor_device *ptdev)
diff --git a/drivers/gpu/drm/panthor/panthor_devfreq.h b/drivers/gpu/drm/panthor/panthor_devfreq.h
index 83a5c9522493..b7631de695f7 100644
--- a/drivers/gpu/drm/panthor/panthor_devfreq.h
+++ b/drivers/gpu/drm/panthor/panthor_devfreq.h
@@ -12,8 +12,8 @@ struct panthor_devfreq;
 
 int panthor_devfreq_init(struct panthor_device *ptdev);
 
-int panthor_devfreq_resume(struct panthor_device *ptdev);
-int panthor_devfreq_suspend(struct panthor_device *ptdev);
+void panthor_devfreq_resume(struct panthor_device *ptdev);
+void panthor_devfreq_suspend(struct panthor_device *ptdev);
 
 void panthor_devfreq_record_busy(struct panthor_device *ptdev);
 void panthor_devfreq_record_idle(struct panthor_device *ptdev);
diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index e701e605d013..e3b22107b268 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -453,9 +453,7 @@ int panthor_device_resume(struct device *dev)
 	if (ret)
 		goto err_disable_stacks_clk;
 
-	ret = panthor_devfreq_resume(ptdev);
-	if (ret)
-		goto err_disable_coregroup_clk;
+	panthor_devfreq_resume(ptdev);
 
 	if (panthor_device_is_initialized(ptdev) &&
 	    drm_dev_enter(&ptdev->base, &cookie)) {
@@ -492,8 +490,6 @@ int panthor_device_resume(struct device *dev)
 
 err_suspend_devfreq:
 	panthor_devfreq_suspend(ptdev);
-
-err_disable_coregroup_clk:
 	clk_disable_unprepare(ptdev->clks.coregroup);
 
 err_disable_stacks_clk:
@@ -510,7 +506,7 @@ int panthor_device_resume(struct device *dev)
 int panthor_device_suspend(struct device *dev)
 {
 	struct panthor_device *ptdev = dev_get_drvdata(dev);
-	int ret, cookie;
+	int cookie;
 
 	if (atomic_read(&ptdev->pm.state) != PANTHOR_DEVICE_PM_STATE_ACTIVE)
 		return -EINVAL;
@@ -542,36 +538,11 @@ int panthor_device_suspend(struct device *dev)
 		drm_dev_exit(cookie);
 	}
 
-	ret = panthor_devfreq_suspend(ptdev);
-	if (ret) {
-		if (panthor_device_is_initialized(ptdev) &&
-		    drm_dev_enter(&ptdev->base, &cookie)) {
-			panthor_gpu_resume(ptdev);
-			panthor_mmu_resume(ptdev);
-			drm_WARN_ON(&ptdev->base, panthor_fw_resume(ptdev));
-			panthor_sched_resume(ptdev);
-			drm_dev_exit(cookie);
-		}
-
-		goto err_set_active;
-	}
+	panthor_devfreq_suspend(ptdev);
 
 	clk_disable_unprepare(ptdev->clks.coregroup);
 	clk_disable_unprepare(ptdev->clks.stacks);
 	clk_disable_unprepare(ptdev->clks.core);
 	atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_SUSPENDED);
 	return 0;
-
-err_set_active:
-	/* If something failed and we have to revert back to an
-	 * active state, we also need to clear the MMIO userspace
-	 * mappings, so any dumb pages that were mapped while we
-	 * were trying to suspend gets invalidated.
-	 */
-	mutex_lock(&ptdev->pm.mmio_lock);
-	atomic_set(&ptdev->pm.state, PANTHOR_DEVICE_PM_STATE_ACTIVE);
-	unmap_mapping_range(ptdev->base.anon_inode->i_mapping,
-			    DRM_PANTHOR_USER_MMIO_OFFSET, 0, 1);
-	mutex_unlock(&ptdev->pm.mmio_lock);
-	return ret;
 }
-- 
2.46.2