drm/nouveau/secboot: check that WPR region is properly set

The ACR firmware may return no error but fail nonetheless. Such cases
can be detected by verifying that the WPR region has been properly set
in FB. If this is not the case, this is an error, but the unload
firmware should still not be run.
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/secboot/acr_r352.c

@@ -876,6 +876,37 @@ acr_r352_shutdown(struct acr_r352 *acr, struct nvkm_secboot *sb)
 	return 0;
 }
 
+/**
+ * Check if the WPR region has been indeed set by the ACR firmware, and
+ * matches where it should be.
+ */
+static bool
+acr_r352_wpr_is_set(const struct acr_r352 *acr, const struct nvkm_secboot *sb)
+{
+	const struct nvkm_subdev *subdev = &sb->subdev;
+	const struct nvkm_device *device = subdev->device;
+	u64 wpr_lo, wpr_hi;
+	u64 wpr_range_lo, wpr_range_hi;
+
+	nvkm_wr32(device, 0x100cd4, 0x2);
+	wpr_lo = (nvkm_rd32(device, 0x100cd4) & ~0xff);
+	wpr_lo <<= 8;
+	nvkm_wr32(device, 0x100cd4, 0x3);
+	wpr_hi = (nvkm_rd32(device, 0x100cd4) & ~0xff);
+	wpr_hi <<= 8;
+
+	if (sb->wpr_size != 0) {
+		wpr_range_lo = sb->wpr_addr;
+		wpr_range_hi = wpr_range_lo + sb->wpr_size;
+	} else {
+		wpr_range_lo = acr->ls_blob->addr;
+		wpr_range_hi = wpr_range_lo + acr->ls_blob->size;
+	}
+
+	return (wpr_lo >= wpr_range_lo && wpr_lo < wpr_range_hi &&
+		wpr_hi > wpr_range_lo && wpr_hi <= wpr_range_hi);
+}
+
 static int
 acr_r352_bootstrap(struct acr_r352 *acr, struct nvkm_secboot *sb)
 {
@@ -896,11 +927,17 @@ acr_r352_bootstrap(struct acr_r352 *acr, struct nvkm_secboot *sb)
 	ret = sb->func->run_blob(sb, acr->load_blob);
 	/* clear halt interrupt */
 	nvkm_falcon_clear_interrupt(sb->boot_falcon, 0x10);
+	sb->wpr_set = acr_r352_wpr_is_set(acr, sb);
 	if (ret)
 		return ret;
 	nvkm_debug(subdev, "HS load blob completed\n");
-
-	sb->wpr_set = true;
+	if (ret)
+		return ret;
+	/* WPR must be set at this point */
+	if (!sb->wpr_set) {
+		nvkm_error(subdev, "ACR blob completed but WPR not set!\n");
+		return -EINVAL;
+	}
 
 	/* Run LS firmwares post_run hooks */
 	for_each_set_bit(falcon_id, &managed_falcons, NVKM_SECBOOT_FALCON_END) {