drm/nouveau/device: detect if changing endianness failed

v2: relax the checks a little

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
index 37589f3..c732074 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/base.c
@@ -2924,6 +2924,20 @@ nvkm_device_del(struct nvkm_device **pdevice)
        }
 }
 
+static inline bool
+nvkm_device_endianness(void __iomem *pri)
+{
+       u32 boot1 = ioread32_native(pri + 0x000004) & 0x01000001;
+#ifdef __BIG_ENDIAN
+       if (!boot1)
+               return false;
+#else
+       if (boot1)
+               return false;
+#endif
+       return true;
+}
+
 int
 nvkm_device_ctor(const struct nvkm_device_func *func,
                 const struct nvkm_device_quirk *quirk,
@@ -2973,13 +2987,15 @@ nvkm_device_ctor(const struct nvkm_device_func *func,
        /* identify the chipset, and determine classes of subdev/engines */
        if (detect) {
                /* switch mmio to cpu's native endianness */
-#ifndef __BIG_ENDIAN
-               if (ioread32_native(map + 0x000004) != 0x00000000) {
-#else
-               if (ioread32_native(map + 0x000004) == 0x00000000) {
-#endif
+               if (!nvkm_device_endianness(map)) {
                        iowrite32_native(0x01000001, map + 0x000004);
                        ioread32_native(map);
+                       if (!nvkm_device_endianness(map)) {
+                               nvdev_error(device,
+                                           "GPU not supported on big-endian\n");
+                               ret = -ENOSYS;
+                               goto done;
+                       }
                }
 
                /* read boot0 and strapping information */