drm/cirrus: add drm_driver.release callback.

Move final cleanups from cirrus_pci_remove() to the new callback.
Add drm_atomic_helper_shutdown() call to cirrus_pci_remove().

Use drm_dev_{enter,exit,unplug} to avoid touching hardware after
device removal.

v4: add changelog.
v3: use drm_dev*.
v2: stop touching hardware after pci_remove().
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20200211135522.23654-1-kraxel@redhat.com

drivers/gpu/drm/cirrus/cirrus.c

@@ -151,9 +151,13 @@ static int cirrus_pitch(struct drm_framebuffer *fb)
 
 static void cirrus_set_start_address(struct cirrus_device *cirrus, u32 offset)
 {
+	int idx;
 	u32 addr;
 	u8 tmp;
 
+	if (!drm_dev_enter(&cirrus->dev, &idx))
+		return;
+
 	addr = offset >> 2;
 	wreg_crt(cirrus, 0x0c, (u8)((addr >> 8) & 0xff));
 	wreg_crt(cirrus, 0x0d, (u8)(addr & 0xff));
@@ -168,6 +172,8 @@ static void cirrus_set_start_address(struct cirrus_device *cirrus, u32 offset)
 	tmp &= 0x7f;
 	tmp |= (addr >> 12) & 0x80;
 	wreg_crt(cirrus, 0x1d, tmp);
+
+	drm_dev_exit(idx);
 }
 
 static int cirrus_mode_set(struct cirrus_device *cirrus,
@@ -176,9 +182,12 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
 {
 	int hsyncstart, hsyncend, htotal, hdispend;
 	int vtotal, vdispend;
-	int tmp;
+	int tmp, idx;
 	int sr07 = 0, hdr = 0;
 
+	if (!drm_dev_enter(&cirrus->dev, &idx))
+		return -1;
+
 	htotal = mode->htotal / 8;
 	hsyncend = mode->hsync_end / 8;
 	hsyncstart = mode->hsync_start / 8;
@@ -264,6 +273,7 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
 		hdr = 0xc5;
 		break;
 	default:
+		drm_dev_exit(idx);
 		return -1;
 	}
 
@@ -292,6 +302,8 @@ static int cirrus_mode_set(struct cirrus_device *cirrus,
 
 	/* Unblank (needed on S3 resume, vgabios doesn't do it then) */
 	outb(0x20, 0x3c0);
+
+	drm_dev_exit(idx);
 	return 0;
 }
 
@@ -300,10 +312,16 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
 {
 	struct cirrus_device *cirrus = fb->dev->dev_private;
 	void *vmap;
+	int idx, ret;
 
+	ret = -ENODEV;
+	if (!drm_dev_enter(&cirrus->dev, &idx))
+		goto out;
+
+	ret = -ENOMEM;
 	vmap = drm_gem_shmem_vmap(fb->obj[0]);
 	if (!vmap)
-		return -ENOMEM;
+		goto out_dev_exit;
 
 	if (cirrus->cpp == fb->format->cpp[0])
 		drm_fb_memcpy_dstclip(cirrus->vram,
@@ -323,7 +341,12 @@ static int cirrus_fb_blit_rect(struct drm_framebuffer *fb,
 		WARN_ON_ONCE("cpp mismatch");
 
 	drm_gem_shmem_vunmap(fb->obj[0], vmap);
-	return 0;
+	ret = 0;
+
+out_dev_exit:
+	drm_dev_exit(idx);
+out:
+	return ret;
 }
 
 static int cirrus_fb_blit_fullscreen(struct drm_framebuffer *fb)
@@ -502,6 +525,14 @@ static void cirrus_mode_config_init(struct cirrus_device *cirrus)
 
 /* ------------------------------------------------------------------ */
 
+static void cirrus_release(struct drm_device *dev)
+{
+	struct cirrus_device *cirrus = dev->dev_private;
+
+	drm_mode_config_cleanup(dev);
+	kfree(cirrus);
+}
+
 DEFINE_DRM_GEM_FOPS(cirrus_fops);
 
 static struct drm_driver cirrus_driver = {
@@ -515,6 +546,7 @@ static struct drm_driver cirrus_driver = {
 
 	.fops		 = &cirrus_fops,
 	DRM_GEM_SHMEM_DRIVER_OPS,
+	.release         = cirrus_release,
 };
 
 static int cirrus_pci_probe(struct pci_dev *pdev,
@@ -598,12 +630,11 @@ static void cirrus_pci_remove(struct pci_dev *pdev)
 	struct drm_device *dev = pci_get_drvdata(pdev);
 	struct cirrus_device *cirrus = dev->dev_private;
 
-	drm_dev_unregister(dev);
-	drm_mode_config_cleanup(dev);
+	drm_dev_unplug(dev);
+	drm_atomic_helper_shutdown(dev);
 	iounmap(cirrus->mmio);
 	iounmap(cirrus->vram);
 	drm_dev_put(dev);
-	kfree(cirrus);
 	pci_release_regions(pdev);
 }