accel/ivpu: Do not access HW registers after unbind

We should not access hardware after we unbind from the bus.

Use drm_dev_enter() / drm_dev_exit() to mark code sections where
hardware is accessed (and not already protected by other locks)
and drm_dev_unplug() to mark device is gone.

Fixes: 35b1376 ("accel/ivpu: Introduce a new DRM driver for Intel VPU")
Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Reviewed-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Signed-off-by: Jacek Lawrynowicz <jacek.lawrynowicz@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230323125504.2586442-2-stanislaw.gruszka@linux.intel.com

Author: Stanislaw Gruszka

drivers/accel/ivpu/ivpu_drv.c

@@ -8,7 +8,6 @@
 #include <linux/pci.h>
 
 #include <drm/drm_accel.h>
-#include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 #include <drm/drm_gem.h>
 #include <drm/drm_ioctl.h>
@@ -118,6 +117,10 @@ static int ivpu_get_param_ioctl(struct drm_device *dev, void *data, struct drm_f
 	struct pci_dev *pdev = to_pci_dev(vdev->drm.dev);
 	struct drm_ivpu_param *args = data;
 	int ret = 0;
+	int idx;
+
+	if (!drm_dev_enter(dev, &idx))
+		return -ENODEV;
 
 	switch (args->param) {
 	case DRM_IVPU_PARAM_DEVICE_ID:
@@ -171,6 +174,7 @@ static int ivpu_get_param_ioctl(struct drm_device *dev, void *data, struct drm_f
 		break;
 	}
 
+	drm_dev_exit(idx);
 	return ret;
 }
 
@@ -622,7 +626,7 @@ static void ivpu_remove(struct pci_dev *pdev)
 {
 	struct ivpu_device *vdev = pci_get_drvdata(pdev);
 
-	drm_dev_unregister(&vdev->drm);
+	drm_dev_unplug(&vdev->drm);
 	ivpu_dev_fini(vdev);
 }
 

drivers/accel/ivpu/ivpu_drv.h

@@ -7,6 +7,7 @@
 #define __IVPU_DRV_H__
 
 #include <drm/drm_device.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_mm.h>
 #include <drm/drm_print.h>

drivers/accel/ivpu/ivpu_job.c

@@ -489,12 +489,12 @@ ivpu_job_prepare_bos_for_submit(struct drm_file *file, struct ivpu_job *job, u32
 
 int ivpu_submit_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 {
-	int ret = 0;
 	struct ivpu_file_priv *file_priv = file->driver_priv;
 	struct ivpu_device *vdev = file_priv->vdev;
 	struct drm_ivpu_submit *params = data;
 	struct ivpu_job *job;
 	u32 *buf_handles;
+	int idx, ret;
 
 	if (params->engine > DRM_IVPU_ENGINE_COPY)
 		return -EINVAL;
@@ -523,14 +523,19 @@ int ivpu_submit_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 		goto free_handles;
 	}
 
+	if (!drm_dev_enter(&vdev->drm, &idx)) {
+		ret = -ENODEV;
+		goto free_handles;
+	}
+
 	ivpu_dbg(vdev, JOB, "Submit ioctl: ctx %u buf_count %u\n",
 		 file_priv->ctx.id, params->buffer_count);
 
 	job = ivpu_create_job(file_priv, params->engine, params->buffer_count);
 	if (!job) {
 		ivpu_err(vdev, "Failed to create job\n");
 		ret = -ENOMEM;
-		goto free_handles;
+		goto dev_exit;
 	}
 
 	ret = ivpu_job_prepare_bos_for_submit(file, job, buf_handles, params->buffer_count,
@@ -548,6 +553,8 @@ int ivpu_submit_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
 
 job_put:
 	job_put(job);
+dev_exit:
+	drm_dev_exit(idx);
 free_handles:
 	kfree(buf_handles);