drm/simpledrm: Request memory region in driver

Requesting the framebuffer memory in simpledrm marks the memory
range as busy. This used to be done by the firmware sysfb code,
but the driver is the correct place.

v2:
	* use I/O memory if request_mem_region() fails (Jocelyn)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220125091222.21457-4-tzimmermann@suse.de

drivers/gpu/drm/tiny/simpledrm.c

@@ -526,21 +526,33 @@ static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
 {
 	struct drm_device *dev = &sdev->dev;
 	struct platform_device *pdev = sdev->pdev;
-	struct resource *mem;
+	struct resource *res, *mem;
 	void __iomem *screen_base;
 	int ret;
 
-	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!mem)
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
 		return -EINVAL;
 
-	ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));
+	ret = devm_aperture_acquire_from_firmware(dev, res->start, resource_size(res));
 	if (ret) {
 		drm_err(dev, "could not acquire memory range %pr: error %d\n",
-			mem, ret);
+			res, ret);
 		return ret;
 	}
 
+	mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res),
+				      sdev->dev.driver->name);
+	if (!mem) {
+		/*
+		 * We cannot make this fatal. Sometimes this comes from magic
+		 * spaces our resource handlers simply don't know about. Use
+		 * the I/O-memory resource as-is and try to map that instead.
+		 */
+		drm_warn(dev, "could not acquire memory region %pr\n", res);
+		mem = res;
+	}
+
 	screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
 				      resource_size(mem));
 	if (!screen_base)