drm/bochs: add drm_driver.release callback.

Call bochs_unload via drm_driver.release to make sure we release stuff
when it is safe to do so.  Use drm_dev_{enter,exit,unplug} to avoid
touching hardware after device removal.  Tidy up here and there.

v4: add changelog.
v3: use drm_dev_*().
v2: move hardware deinit to 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/20200211135218.22871-1-kraxel@redhat.com

drivers/gpu/drm/bochs/bochs_drv.c

@@ -23,7 +23,6 @@ static void bochs_unload(struct drm_device *dev)
 
 	bochs_kms_fini(bochs);
 	bochs_mm_fini(bochs);
-	bochs_hw_fini(dev);
 	kfree(bochs);
 	dev->dev_private = NULL;
 }
@@ -69,6 +68,7 @@ static struct drm_driver bochs_driver = {
 	.major			= 1,
 	.minor			= 0,
 	DRM_GEM_VRAM_DRIVER,
+	.release                = bochs_unload,
 };
 
 /* ---------------------------------------------------------------------- */
@@ -148,9 +148,9 @@ static void bochs_pci_remove(struct pci_dev *pdev)
 {
 	struct drm_device *dev = pci_get_drvdata(pdev);
 
+	drm_dev_unplug(dev);
 	drm_atomic_helper_shutdown(dev);
-	drm_dev_unregister(dev);
-	bochs_unload(dev);
+	bochs_hw_fini(dev);
 	drm_dev_put(dev);
 }
 

drivers/gpu/drm/bochs/bochs_hw.c

@@ -4,6 +4,7 @@
 
 #include <linux/pci.h>
 
+#include <drm/drm_drv.h>
 #include <drm/drm_fourcc.h>
 
 #include "bochs.h"
@@ -194,6 +195,8 @@ void bochs_hw_fini(struct drm_device *dev)
 {
 	struct bochs_device *bochs = dev->dev_private;
 
+	/* TODO: shot down existing vram mappings */
+
 	if (bochs->mmio)
 		iounmap(bochs->mmio);
 	if (bochs->ioports)
@@ -207,6 +210,11 @@ void bochs_hw_fini(struct drm_device *dev)
 void bochs_hw_setmode(struct bochs_device *bochs,
 		      struct drm_display_mode *mode)
 {
+	int idx;
+
+	if (!drm_dev_enter(bochs->dev, &idx))
+		return;
+
 	bochs->xres = mode->hdisplay;
 	bochs->yres = mode->vdisplay;
 	bochs->bpp = 32;
@@ -232,11 +240,18 @@ void bochs_hw_setmode(struct bochs_device *bochs,
 
 	bochs_dispi_write(bochs, VBE_DISPI_INDEX_ENABLE,
 			  VBE_DISPI_ENABLED | VBE_DISPI_LFB_ENABLED);
+
+	drm_dev_exit(idx);
 }
 
 void bochs_hw_setformat(struct bochs_device *bochs,
 			const struct drm_format_info *format)
 {
+	int idx;
+
+	if (!drm_dev_enter(bochs->dev, &idx))
+		return;
+
 	DRM_DEBUG_DRIVER("format %c%c%c%c\n",
 			 (format->format >>  0) & 0xff,
 			 (format->format >>  8) & 0xff,
@@ -256,13 +271,18 @@ void bochs_hw_setformat(struct bochs_device *bochs,
 			  __func__, format->format);
 		break;
 	}
+
+	drm_dev_exit(idx);
 }
 
 void bochs_hw_setbase(struct bochs_device *bochs,
 		      int x, int y, int stride, u64 addr)
 {
 	unsigned long offset;
-	unsigned int vx, vy, vwidth;
+	unsigned int vx, vy, vwidth, idx;
+
+	if (!drm_dev_enter(bochs->dev, &idx))
+		return;
 
 	bochs->stride = stride;
 	offset = (unsigned long)addr +
@@ -277,4 +297,6 @@ void bochs_hw_setbase(struct bochs_device *bochs,
 	bochs_dispi_write(bochs, VBE_DISPI_INDEX_VIRT_WIDTH, vwidth);
 	bochs_dispi_write(bochs, VBE_DISPI_INDEX_X_OFFSET, vx);
 	bochs_dispi_write(bochs, VBE_DISPI_INDEX_Y_OFFSET, vy);
+
+	drm_dev_exit(idx);
 }