drm/imagination: Fix kernel crash when hard resetting the GPU

The GPU hard reset sequence calls pm_runtime_force_suspend() and
pm_runtime_force_resume(), which according to their documentation should
only be used during system-wide PM transitions to sleep states.

The main issue though is that depending on some internal runtime PM
state as seen by pm_runtime_force_suspend() (whether the usage count is
<= 1), pm_runtime_force_resume() might not resume the device unless
needed. If that happens, the runtime PM resume callback
pvr_power_device_resume() is not called, the GPU clocks are not
re-enabled, and the kernel crashes on the next attempt to access GPU
registers as part of the power-on sequence.

Replace calls to pm_runtime_force_suspend() and
pm_runtime_force_resume() with direct calls to the driver's runtime PM
callbacks, pvr_power_device_suspend() and pvr_power_device_resume(),
to ensure clocks are re-enabled and avoid the kernel crash.

Fixes: cc1aeed ("drm/imagination: Implement firmware infrastructure and META FW support")
Signed-off-by: Alessio Belle <[email protected]>
Reviewed-by: Matt Coster <[email protected]>
Link: https://lore.kernel.org/r/20250624-fix-kernel-crash-gpu-hard-reset-v1-1-6d24810d72a6@imgtec.com
Cc: [email protected]
Signed-off-by: Matt Coster <[email protected]>

Author: alessiob-img

drivers/gpu/drm/imagination/pvr_power.c

@@ -386,13 +386,13 @@ pvr_power_reset(struct pvr_device *pvr_dev, bool hard_reset)
 		if (!err) {
 			if (hard_reset) {
 				pvr_dev->fw_dev.booted = false;
-				WARN_ON(pm_runtime_force_suspend(from_pvr_device(pvr_dev)->dev));
+				WARN_ON(pvr_power_device_suspend(from_pvr_device(pvr_dev)->dev));
 
 				err = pvr_fw_hard_reset(pvr_dev);
 				if (err)
 					goto err_device_lost;
 
-				err = pm_runtime_force_resume(from_pvr_device(pvr_dev)->dev);
+				err = pvr_power_device_resume(from_pvr_device(pvr_dev)->dev);
 				pvr_dev->fw_dev.booted = true;
 				if (err)
 					goto err_device_lost;