[PATCH 2/5] drm/panthor: Be robust against runtime PM resume failures in the suspend path

[Boris Brezillon]

The runtime PM resume operation is not guaranteed to succeed, but if it
fails, the device should be in a suspended state. Make sure we're robust
to resume failures in the unplug path.

Signed-off-by: Boris Brezillon <boris.brezillon at collabora.com>
---
 drivers/gpu/drm/panthor/panthor_device.c | 23 ++++++++---------------
 drivers/gpu/drm/panthor/panthor_fw.c     | 14 +++++++++-----
 drivers/gpu/drm/panthor/panthor_gpu.c    |  3 ++-
 drivers/gpu/drm/panthor/panthor_mmu.c    |  3 ++-
 4 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/panthor/panthor_device.c b/drivers/gpu/drm/panthor/panthor_device.c
index db7ba40f771d..8b5d54b2bbb4 100644
--- a/drivers/gpu/drm/panthor/panthor_device.c
+++ b/drivers/gpu/drm/panthor/panthor_device.c
@@ -48,6 +48,8 @@ static int panthor_clk_init(struct panthor_device *ptdev)
 
 void panthor_device_unplug(struct panthor_device *ptdev)
 {
+	int ret;
+
 	/* This function can be called from two different path: the reset work
 	 * and the platform device remove callback. drm_dev_unplug() doesn't
 	 * deal with concurrent callers, so we have to protect drm_dev_unplug()
@@ -74,7 +76,8 @@ void panthor_device_unplug(struct panthor_device *ptdev)
 	 */
 	mutex_unlock(&ptdev->unplug.lock);
 
-	drm_WARN_ON(&ptdev->base, pm_runtime_get_sync(ptdev->base.dev) < 0);
+	ret = pm_runtime_get_sync(ptdev->base.dev);
+	drm_WARN_ON(&ptdev->base, ret < 0);
 
 	/* Now, try to cleanly shutdown the GPU before the device resources
 	 * get reclaimed.
@@ -85,7 +88,10 @@ void panthor_device_unplug(struct panthor_device *ptdev)
 	panthor_gpu_unplug(ptdev);
 
 	pm_runtime_dont_use_autosuspend(ptdev->base.dev);
-	pm_runtime_put_sync_suspend(ptdev->base.dev);
+
+	/* If the resume failed, we don't need to suspend here. */
+	if (!ret)
+		pm_runtime_put_sync_suspend(ptdev->base.dev);
 
 	/* If PM is disabled, we need to call the suspend handler manually. */
 	if (!IS_ENABLED(CONFIG_PM))
@@ -541,17 +547,4 @@ int panthor_device_suspend(struct device *dev)
 	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;
 }
diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
index 2060085cc9f3..df74750cf1b7 100644
--- a/drivers/gpu/drm/panthor/panthor_fw.c
+++ b/drivers/gpu/drm/panthor/panthor_fw.c
@@ -12,6 +12,7 @@
 #include <linux/iosys-map.h>
 #include <linux/mutex.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 
 #include <drm/drm_drv.h>
 #include <drm/drm_managed.h>
@@ -1188,11 +1189,13 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
 
 	cancel_delayed_work_sync(&ptdev->fw->watchdog.ping_work);
 
-	/* Make sure the IRQ handler can be called after that point. */
-	if (ptdev->fw->irq.irq)
-		panthor_job_irq_suspend(&ptdev->fw->irq);
+	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev)) {
+		/* Make sure the IRQ handler can be called after that point. */
+		if (ptdev->fw->irq.irq)
+			panthor_job_irq_suspend(&ptdev->fw->irq);
 
-	panthor_fw_stop(ptdev);
+		panthor_fw_stop(ptdev);
+	}
 
 	list_for_each_entry(section, &ptdev->fw->sections, node)
 		panthor_kernel_bo_destroy(section->mem);
@@ -1205,7 +1208,8 @@ void panthor_fw_unplug(struct panthor_device *ptdev)
 	panthor_vm_put(ptdev->fw->vm);
 	ptdev->fw->vm = NULL;
 
-	panthor_gpu_power_off(ptdev, L2, ptdev->gpu_info.l2_present, 20000);
+	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
+		panthor_gpu_power_off(ptdev, L2, ptdev->gpu_info.l2_present, 20000);
 }
 
 /**
diff --git a/drivers/gpu/drm/panthor/panthor_gpu.c b/drivers/gpu/drm/panthor/panthor_gpu.c
index 2d3529a0b156..27702bc62dd6 100644
--- a/drivers/gpu/drm/panthor/panthor_gpu.c
+++ b/drivers/gpu/drm/panthor/panthor_gpu.c
@@ -174,7 +174,8 @@ void panthor_gpu_unplug(struct panthor_device *ptdev)
 	unsigned long flags;
 
 	/* Make sure the IRQ handler is not running after that point. */
-	panthor_gpu_irq_suspend(&ptdev->gpu->irq);
+	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
+		panthor_gpu_irq_suspend(&ptdev->gpu->irq);
 
 	/* Wake-up all waiters. */
 	spin_lock_irqsave(&ptdev->gpu->reqs_lock, flags);
diff --git a/drivers/gpu/drm/panthor/panthor_mmu.c b/drivers/gpu/drm/panthor/panthor_mmu.c
index c2262c72e8e2..fee6c7d9fe0a 100644
--- a/drivers/gpu/drm/panthor/panthor_mmu.c
+++ b/drivers/gpu/drm/panthor/panthor_mmu.c
@@ -2674,7 +2674,8 @@ int panthor_vm_prepare_mapped_bos_resvs(struct drm_exec *exec, struct panthor_vm
  */
 void panthor_mmu_unplug(struct panthor_device *ptdev)
 {
-	panthor_mmu_irq_suspend(&ptdev->mmu->irq);
+	if (!IS_ENABLED(CONFIG_PM) || pm_runtime_active(ptdev->base.dev))
+		panthor_mmu_irq_suspend(&ptdev->mmu->irq);
 
 	mutex_lock(&ptdev->mmu->as.slots_lock);
 	for (u32 i = 0; i < ARRAY_SIZE(ptdev->mmu->as.slots); i++) {
-- 
2.46.2