drm/qxl: fix qxl can't use in arm64

qxl use ioremap to map ram_header and rom, in the arm64 implementation,
the device is mapped as DEVICE_nGnRE, it can not support unaligned
access. and qxl is a virtual device, it can be treated more like RAM
than actual MMIO registers. use ioremap_wc() replace it.
Signed-off-by: NCong Liu <liucong2@kylinos.cn>
Acked-by: NChristian König <christian.koenig@amd.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20220324104928.2959545-1-liucong2@kylinos.cnSigned-off-by: NGerd Hoffmann <kraxel@redhat.com>

drivers/gpu/drm/qxl/qxl_kms.c

@@ -165,7 +165,7 @@ int qxl_device_init(struct qxl_device *qdev,
 		 (int)qdev->surfaceram_size / 1024,
 		 (sb == 4) ? "64bit" : "32bit");
 
-	qdev->rom = ioremap(qdev->rom_base, qdev->rom_size);
+	qdev->rom = ioremap_wc(qdev->rom_base, qdev->rom_size);
 	if (!qdev->rom) {
 		pr_err("Unable to ioremap ROM\n");
 		r = -ENOMEM;
@@ -183,7 +183,7 @@ int qxl_device_init(struct qxl_device *qdev,
 		goto rom_unmap;
 	}
 
-	qdev->ram_header = ioremap(qdev->vram_base +
+	qdev->ram_header = ioremap_wc(qdev->vram_base +
 				   qdev->rom->ram_header_offset,
 				   sizeof(*qdev->ram_header));
 	if (!qdev->ram_header) {

drivers/gpu/drm/qxl/qxl_ttm.c

@@ -82,13 +82,13 @@ int qxl_ttm_io_mem_reserve(struct ttm_device *bdev,
 	case TTM_PL_VRAM:
 		mem->bus.is_iomem = true;
 		mem->bus.offset = (mem->start << PAGE_SHIFT) + qdev->vram_base;
-		mem->bus.caching = ttm_cached;
+		mem->bus.caching = ttm_write_combined;
 		break;
 	case TTM_PL_PRIV:
 		mem->bus.is_iomem = true;
 		mem->bus.offset = (mem->start << PAGE_SHIFT) +
 			qdev->surfaceram_base;
-		mem->bus.caching = ttm_cached;
+		mem->bus.caching = ttm_write_combined;
 		break;
 	default:
 		return -EINVAL;