drm/mgag200: Use managed interfaces for framebuffer write combining

Replace arch_phys_wc_add() and arch_io_reserve_memtype_wc() with
the rsp managed functions. Allows for removing the cleanup code
for memory management
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210916181601.9146-5-tzimmermann@suse.de

drivers/gpu/drm/mgag200/mgag200_drv.h

@@ -224,8 +224,6 @@ struct mga_device {
 
 	enum mga_type			type;
 
-	int fb_mtrr;
-
 	union {
 		struct {
 			long ref_clk;

drivers/gpu/drm/mgag200/mgag200_mm.c

@@ -75,26 +75,12 @@ static size_t mgag200_probe_vram(struct mga_device *mdev, void __iomem *mem,
 	return offset - 65536;
 }
 
-static void mgag200_mm_release(struct drm_device *dev, void *ptr)
-{
-	struct mga_device *mdev = to_mga_device(dev);
-	struct pci_dev *pdev = to_pci_dev(dev->dev);
-
-	mdev->vram_fb_available = 0;
-	iounmap(mdev->vram);
-	arch_io_free_memtype_wc(pci_resource_start(pdev, 0),
-				pci_resource_len(pdev, 0));
-	arch_phys_wc_del(mdev->fb_mtrr);
-	mdev->fb_mtrr = 0;
-}
-
 int mgag200_mm_init(struct mga_device *mdev)
 {
 	struct drm_device *dev = &mdev->base;
 	struct pci_dev *pdev = to_pci_dev(dev->dev);
 	u8 misc;
 	resource_size_t start, len;
-	int ret;
 
 	WREG_ECRT(0x04, 0x00);
 
@@ -112,15 +98,13 @@ int mgag200_mm_init(struct mga_device *mdev)
 		return -ENXIO;
 	}
 
-	arch_io_reserve_memtype_wc(start, len);
-
-	mdev->fb_mtrr = arch_phys_wc_add(start, len);
+	/* Don't fail on errors, but performance might be reduced. */
+	devm_arch_io_reserve_memtype_wc(dev->dev, start, len);
+	devm_arch_phys_wc_add(dev->dev, start, len);
 
-	mdev->vram = ioremap(start, len);
-	if (!mdev->vram) {
-		ret = -ENOMEM;
-		goto err_arch_phys_wc_del;
-	}
+	mdev->vram = devm_ioremap(dev->dev, start, len);
+	if (!mdev->vram)
+		return -ENOMEM;
 
 	mdev->mc.vram_size = mgag200_probe_vram(mdev, mdev->vram, len);
 	mdev->mc.vram_base = start;
@@ -128,10 +112,5 @@ int mgag200_mm_init(struct mga_device *mdev)
 
 	mdev->vram_fb_available = mdev->mc.vram_size;
 
-	return drmm_add_action_or_reset(dev, mgag200_mm_release, NULL);
-
-err_arch_phys_wc_del:
-	arch_phys_wc_del(mdev->fb_mtrr);
-	arch_io_free_memtype_wc(start, len);
-	return ret;
+	return 0;
 }