drm/nouveau/core: add a macro to better handle multiple firmware versions

Will be used in upcoming commits to allow subdevs to better customise
themselves based on which (if any) firmware is available.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/core/firmware.h

 /* SPDX-License-Identifier: MIT */
 #ifndef __NVKM_FIRMWARE_H__
 #define __NVKM_FIRMWARE_H__
+#include <core/option.h>
 #include <core/subdev.h>
 
 int nvkm_firmware_get_version(const struct nvkm_subdev *, const char *fwname,
@@ -9,4 +10,43 @@ int nvkm_firmware_get_version(const struct nvkm_subdev *, const char *fwname,
 int nvkm_firmware_get(const struct nvkm_subdev *, const char *fwname,
 		      const struct firmware **);
 void nvkm_firmware_put(const struct firmware *);
+
+#define nvkm_firmware_load(s,l,o,p...) ({                                      \
+	struct nvkm_subdev *_s = (s);                                          \
+	const char *_opts = (o);                                               \
+	char _option[32];                                                      \
+	typeof(l[0]) *_list = (l), *_next, *_fwif = NULL;                      \
+	int _ver, _fwv, _ret = 0;                                              \
+                                                                               \
+	snprintf(_option, sizeof(_option), "Nv%sFw", _opts);                   \
+	_ver = nvkm_longopt(_s->device->cfgopt, _option, -2);                  \
+	if (_ver >= -1) {                                                      \
+		for (_next = _list; !_fwif && _next->load; _next++) {          \
+			if (_next->version == _ver)                            \
+				_fwif = _next;                                 \
+		}                                                              \
+		_ret = _fwif ? 0 : -EINVAL;                                    \
+	}                                                                      \
+                                                                               \
+	if (_ret == 0) {                                                       \
+		snprintf(_option, sizeof(_option), "Nv%sFwVer", _opts);        \
+		_fwv = _fwif ? _fwif->version : -1;                            \
+		_ver = nvkm_longopt(_s->device->cfgopt, _option, _fwv);        \
+		for (_next = _fwif ? _fwif : _list; _next->load; _next++) {    \
+			_fwv = (_ver >= 0) ? _ver : _next->version;            \
+			_ret = _next->load(p, _fwv, _next);                    \
+			if (_ret == 0 || _ver >= 0) {                          \
+				_fwif = _next;                                 \
+				break;                                         \
+			}                                                      \
+		}                                                              \
+	}                                                                      \
+                                                                               \
+	if (_ret) {                                                            \
+		nvkm_error(_s, "failed to load firmware\n");                   \
+		_fwif = ERR_PTR(_ret);                                         \
+	}                                                                      \
+	                                                                       \
+	_fwif;                                                                 \
+})
 #endif