drm/nouveau/device: implement a generic method to query device-specific properties

We have a need to fetch data from GPU-specific sub-devices that is not
tied to any particular engine object.

This commit provides the framework to support such queries.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvif/cl0080.h

@@ -39,9 +39,25 @@ struct nv_device_info_v0 {
 	char  name[64];
 };
 
+struct nv_device_info_v1 {
+	__u8  version;
+	__u8  count;
+	__u8  pad02[6];
+	struct nv_device_info_v1_data {
+		__u64 mthd; /* NV_DEVICE_INFO_* (see below). */
+		__u64 data;
+	} data[];
+};
+
 struct nv_device_time_v0 {
 	__u8  version;
 	__u8  pad01[7];
 	__u64 time;
 };
+
+#define NV_DEVICE_INFO_UNIT                               (0xffffffffULL << 32)
+#define NV_DEVICE_INFO(n)                          ((n) | (0x00000000ULL << 32))
+
+/* This will be returned for unsupported queries. */
+#define NV_DEVICE_INFO_INVALID                                           ~0ULL
 #endif

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

@@ -18,6 +18,7 @@ struct nvkm_engine_func {
 	void *(*dtor)(struct nvkm_engine *);
 	void (*preinit)(struct nvkm_engine *);
 	int (*oneinit)(struct nvkm_engine *);
+	int (*info)(struct nvkm_engine *, u64 mthd, u64 *data);
 	int (*init)(struct nvkm_engine *);
 	int (*fini)(struct nvkm_engine *, bool suspend);
 	void (*intr)(struct nvkm_engine *);

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

@@ -17,6 +17,7 @@ struct nvkm_subdev_func {
 	void *(*dtor)(struct nvkm_subdev *);
 	int (*preinit)(struct nvkm_subdev *);
 	int (*oneinit)(struct nvkm_subdev *);
+	int (*info)(struct nvkm_subdev *, u64 mthd, u64 *data);
 	int (*init)(struct nvkm_subdev *);
 	int (*fini)(struct nvkm_subdev *, bool suspend);
 	void (*intr)(struct nvkm_subdev *);
@@ -29,6 +30,7 @@ void nvkm_subdev_del(struct nvkm_subdev **);
 int  nvkm_subdev_preinit(struct nvkm_subdev *);
 int  nvkm_subdev_init(struct nvkm_subdev *);
 int  nvkm_subdev_fini(struct nvkm_subdev *, bool suspend);
+int  nvkm_subdev_info(struct nvkm_subdev *, u64, u64 *);
 void nvkm_subdev_intr(struct nvkm_subdev *);
 
 /* subdev logging */

drivers/gpu/drm/nouveau/nvkm/core/engine.c

@@ -82,6 +82,20 @@ nvkm_engine_intr(struct nvkm_subdev *subdev)
 		engine->func->intr(engine);
 }
 
+static int
+nvkm_engine_info(struct nvkm_subdev *subdev, u64 mthd, u64 *data)
+{
+	struct nvkm_engine *engine = nvkm_engine(subdev);
+	if (engine->func->info) {
+		if ((engine = nvkm_engine_ref(engine))) {
+			int ret = engine->func->info(engine, mthd, data);
+			nvkm_engine_unref(&engine);
+			return ret;
+		}
+	}
+	return -ENOSYS;
+}
+
 static int
 nvkm_engine_fini(struct nvkm_subdev *subdev, bool suspend)
 {
@@ -150,6 +164,7 @@ nvkm_engine_func = {
 	.preinit = nvkm_engine_preinit,
 	.init = nvkm_engine_init,
 	.fini = nvkm_engine_fini,
+	.info = nvkm_engine_info,
 	.intr = nvkm_engine_intr,
 };
 

drivers/gpu/drm/nouveau/nvkm/core/subdev.c

@@ -92,6 +92,14 @@ nvkm_subdev_intr(struct nvkm_subdev *subdev)
 		subdev->func->intr(subdev);
 }
 
+int
+nvkm_subdev_info(struct nvkm_subdev *subdev, u64 mthd, u64 *data)
+{
+	if (subdev->func->info)
+		return subdev->func->info(subdev, mthd, data);
+	return -ENOSYS;
+}
+
 int
 nvkm_subdev_fini(struct nvkm_subdev *subdev, bool suspend)
 {

drivers/gpu/drm/nouveau/nvkm/engine/device/user.c

@@ -39,6 +39,40 @@ struct nvkm_udevice {
 	struct nvkm_device *device;
 };
 
+static int
+nvkm_udevice_info_subdev(struct nvkm_device *device, u64 mthd, u64 *data)
+{
+	struct nvkm_subdev *subdev;
+	enum nvkm_devidx subidx;
+
+	switch (mthd & NV_DEVICE_INFO_UNIT) {
+	default:
+		return -EINVAL;
+	}
+
+	subdev = nvkm_device_subdev(device, subidx);
+	if (subdev)
+		return nvkm_subdev_info(subdev, mthd, data);
+	return -ENODEV;
+}
+
+static void
+nvkm_udevice_info_v1(struct nvkm_device *device,
+		     struct nv_device_info_v1_data *args)
+{
+	if (args->mthd & NV_DEVICE_INFO_UNIT) {
+		if (nvkm_udevice_info_subdev(device, args->mthd, &args->data))
+			args->mthd = NV_DEVICE_INFO_INVALID;
+		return;
+	}
+
+	switch (args->mthd) {
+	default:
+		args->mthd = NV_DEVICE_INFO_INVALID;
+		break;
+	}
+}
+
 static int
 nvkm_udevice_info(struct nvkm_udevice *udev, void *data, u32 size)
 {
@@ -48,10 +82,21 @@ nvkm_udevice_info(struct nvkm_udevice *udev, void *data, u32 size)
 	struct nvkm_instmem *imem = device->imem;
 	union {
 		struct nv_device_info_v0 v0;
+		struct nv_device_info_v1 v1;
 	} *args = data;
-	int ret = -ENOSYS;
+	int ret = -ENOSYS, i;
 
 	nvif_ioctl(object, "device info size %d\n", size);
+	if (!(ret = nvif_unpack(ret, &data, &size, args->v1, 1, 1, true))) {
+		nvif_ioctl(object, "device info vers %d count %d\n",
+			   args->v1.version, args->v1.count);
+		if (args->v1.count * sizeof(args->v1.data[0]) == size) {
+			for (i = 0; i < args->v1.count; i++)
+				nvkm_udevice_info_v1(device, &args->v1.data[i]);
+			return 0;
+		}
+		return -EINVAL;
+	} else
 	if (!(ret = nvif_unpack(ret, &data, &size, args->v0, 0, 0, false))) {
 		nvif_ioctl(object, "device info vers %d\n", args->v0.version);
 	} else