drm/nouveau/nvkm: add a replacement for nvkm_notify

This replaces the twisty, confusing, relationship between nvkm_event and
nvkm_notify with something much simpler, and less racey.  It also places
events in the object tree hierachy, which will allow a bunch of the code
tracking events across allocation/teardown/suspend to be removed.

This commit just adds the new interfaces, and passes the owning subdev to
the event constructor to enable debug-tracing in the new code.

v2:
- use ?: (lyude)

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Reviewed-by: Lyude Paul <lyude@redhat.com>

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

@@ -32,6 +32,8 @@
 #define NVIF_CLASS_VMM_GM200                         /* ifb00d.h */  0x8000b00d
 #define NVIF_CLASS_VMM_GP100                         /* ifc00d.h */  0x8000c00d
 
+#define NVIF_CLASS_EVENT                             /* if000e.h */  0x8000000e
+
 #define NVIF_CLASS_DISP                              /* if0010.h */  0x80000010
 #define NVIF_CLASS_CONN                              /* if0011.h */  0x80000011
 #define NVIF_CLASS_OUTP                              /* if0012.h */  0x80000012

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

@@ -1,6 +1,30 @@
 /* SPDX-License-Identifier: MIT */
 #ifndef __NVIF_EVENT_H__
 #define __NVIF_EVENT_H__
+#include <nvif/object.h>
+#include <nvif/if000e.h>
+struct nvif_event;
+
+#define NVIF_EVENT_KEEP 0
+#define NVIF_EVENT_DROP 1
+typedef int (*nvif_event_func)(struct nvif_event *, void *repv, u32 repc);
+
+struct nvif_event {
+	struct nvif_object object;
+	nvif_event_func func;
+};
+
+static inline bool
+nvif_event_constructed(struct nvif_event *event)
+{
+	return nvif_object_constructed(&event->object);
+}
+
+int nvif_event_ctor(struct nvif_object *parent, const char *name, u32 handle, nvif_event_func,
+		    bool wait, struct nvif_event_v0 *args, u32 argc, struct nvif_event *);
+void nvif_event_dtor(struct nvif_event *);
+int nvif_event_allow(struct nvif_event *);
+int nvif_event_block(struct nvif_event *);
 
 struct nvif_notify_req_v0 {
 	__u8  version;

drivers/gpu/drm/nouveau/include/nvif/if000e.h

@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: MIT */
+#ifndef __NVIF_IF000E_H__
+#define __NVIF_IF000E_H__
+
+union nvif_event_args {
+	struct nvif_event_v0 {
+		__u8 version;
+		__u8 wait;
+		__u8 pad02[6];
+		__u8 data[];
+	} v0;
+};
+
+#define NVIF_EVENT_V0_ALLOW 0x00
+#define NVIF_EVENT_V0_BLOCK 0x01
+
+union nvif_event_allow_args {
+	struct nvif_event_allow_vn {
+	} vn;
+};
+
+union nvif_event_block_args {
+	struct nvif_event_block_vn {
+	} vn;
+};
+#endif

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

@@ -15,6 +15,7 @@ struct nvkm_client {
 
 	void *data;
 	int (*ntfy)(const void *, u32, const void *, u32);
+	int (*event)(u64 token, void *argv, u32 argc);
 
 	struct list_head umem;
 	spinlock_t lock;
@@ -23,6 +24,7 @@ struct nvkm_client {
 int  nvkm_client_new(const char *name, u64 device, const char *cfg,
 		     const char *dbg,
 		     int (*)(const void *, u32, const void *, u32),
+		     int (*)(u64, void *, u32),
 		     struct nvkm_client **);
 struct nvkm_client *nvkm_client_search(struct nvkm_client *, u64 handle);
 

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

@@ -4,9 +4,12 @@
 #include <core/os.h>
 struct nvkm_notify;
 struct nvkm_object;
+struct nvkm_oclass;
+struct nvkm_uevent;
 
 struct nvkm_event {
 	const struct nvkm_event_func *func;
+	struct nvkm_subdev *subdev;
 
 	int types_nr;
 	int index_nr;
@@ -15,6 +18,8 @@ struct nvkm_event {
 	spinlock_t list_lock;
 	struct list_head list;
 	int *refs;
+
+	struct list_head ntfy;
 };
 
 struct nvkm_event_func {
@@ -25,11 +30,42 @@ struct nvkm_event_func {
 	void (*fini)(struct nvkm_event *, int type, int index);
 };
 
-int  nvkm_event_init(const struct nvkm_event_func *func, int types_nr,
+int  nvkm_event_init(const struct nvkm_event_func *func, struct nvkm_subdev *, int types_nr,
 		     int index_nr, struct nvkm_event *);
 void nvkm_event_fini(struct nvkm_event *);
 void nvkm_event_get(struct nvkm_event *, u32 types, int index);
 void nvkm_event_put(struct nvkm_event *, u32 types, int index);
 void nvkm_event_send(struct nvkm_event *, u32 types, int index,
 		     void *data, u32 size);
+
+#define NVKM_EVENT_KEEP 0
+#define NVKM_EVENT_DROP 1
+struct nvkm_event_ntfy;
+typedef int (*nvkm_event_func)(struct nvkm_event_ntfy *, u32 bits);
+
+struct nvkm_event_ntfy {
+	struct nvkm_event *event;
+	int id;
+	u32 bits;
+	bool wait;
+	nvkm_event_func func;
+
+	atomic_t allowed;
+	bool running;
+
+	struct list_head head;
+};
+
+void nvkm_event_ntfy(struct nvkm_event *, int id, u32 bits);
+bool nvkm_event_ntfy_valid(struct nvkm_event *, int id, u32 bits);
+void nvkm_event_ntfy_add(struct nvkm_event *, int id, u32 bits, bool wait, nvkm_event_func,
+			 struct nvkm_event_ntfy *);
+void nvkm_event_ntfy_del(struct nvkm_event_ntfy *);
+void nvkm_event_ntfy_allow(struct nvkm_event_ntfy *);
+void nvkm_event_ntfy_block(struct nvkm_event_ntfy *);
+
+typedef int (*nvkm_uevent_func)(struct nvkm_object *, u64 token, u32 bits);
+
+int nvkm_uevent_new(const struct nvkm_oclass *, void *argv, u32 argc, struct nvkm_object **);
+int nvkm_uevent_add(struct nvkm_uevent *, struct nvkm_event *, int id, u32 bits, nvkm_uevent_func);
 #endif

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

@@ -4,6 +4,7 @@
 #include <core/oclass.h>
 struct nvkm_event;
 struct nvkm_gpuobj;
+struct nvkm_uevent;
 
 struct nvkm_object {
 	const struct nvkm_object_func *func;
@@ -43,6 +44,7 @@ struct nvkm_object_func {
 	int (*bind)(struct nvkm_object *, struct nvkm_gpuobj *, int align,
 		    struct nvkm_gpuobj **);
 	int (*sclass)(struct nvkm_object *, int index, struct nvkm_oclass *);
+	int (*uevent)(struct nvkm_object *, void *argv, u32 argc, struct nvkm_uevent *);
 };
 
 void nvkm_object_ctor(const struct nvkm_object_func *,

drivers/gpu/drm/nouveau/nouveau_nvif.c

@@ -71,11 +71,24 @@ nvkm_client_suspend(void *priv)
 	return nvkm_object_fini(&client->object, true);
 }
 
+static int
+nvkm_client_event(u64 token, void *repv, u32 repc)
+{
+	struct nvif_object *object = (void *)(unsigned long)token;
+	struct nvif_event *event = container_of(object, typeof(*event), object);
+
+	if (event->func(event, repv, repc) == NVIF_EVENT_KEEP)
+		return NVKM_EVENT_KEEP;
+
+	return NVKM_EVENT_DROP;
+}
+
 static int
 nvkm_client_driver_init(const char *name, u64 device, const char *cfg,
 			const char *dbg, void **ppriv)
 {
-	return nvkm_client_new(name, device, cfg, dbg, nvif_notify, (struct nvkm_client **)ppriv);
+	return nvkm_client_new(name, device, cfg, dbg, nvif_notify, nvkm_client_event,
+			       (struct nvkm_client **)ppriv);
 }
 
 const struct nvif_driver

drivers/gpu/drm/nouveau/nvif/Kbuild

@@ -5,6 +5,7 @@ nvif-y += nvif/conn.o
 nvif-y += nvif/device.o
 nvif-y += nvif/disp.o
 nvif-y += nvif/driver.o
+nvif-y += nvif/event.o
 nvif-y += nvif/fifo.o
 nvif-y += nvif/head.o
 nvif-y += nvif/mem.o

drivers/gpu/drm/nouveau/nvif/event.c

@@ -0,0 +1,79 @@
+/*
+ * Copyright 2021 Red Hat Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+#include <nvif/event.h>
+#include <nvif/printf.h>
+
+#include <nvif/class.h>
+#include <nvif/if000e.h>
+
+int
+nvif_event_block(struct nvif_event *event)
+{
+	if (nvif_event_constructed(event)) {
+		int ret = nvif_mthd(&event->object, NVIF_EVENT_V0_BLOCK, NULL, 0);
+		NVIF_ERRON(ret, &event->object, "[BLOCK]");
+		return ret;
+	}
+	return 0;
+}
+
+int
+nvif_event_allow(struct nvif_event *event)
+{
+	if (nvif_event_constructed(event)) {
+		int ret = nvif_mthd(&event->object, NVIF_EVENT_V0_ALLOW, NULL, 0);
+		NVIF_ERRON(ret, &event->object, "[ALLOW]");
+		return ret;
+	}
+	return 0;
+}
+
+void
+nvif_event_dtor(struct nvif_event *event)
+{
+	nvif_object_dtor(&event->object);
+}
+
+int
+nvif_event_ctor(struct nvif_object *parent, const char *name, u32 handle, nvif_event_func func,
+		bool wait, struct nvif_event_v0 *args, u32 argc, struct nvif_event *event)
+{
+	struct nvif_event_v0 _args;
+	int ret;
+
+	if (!args) {
+		args = &_args;
+		argc = sizeof(_args);
+	}
+
+	args->version = 0;
+	args->wait = wait;
+
+	ret = nvif_object_ctor(parent, name ?: "nvifEvent", handle,
+			       NVIF_CLASS_EVENT, args, argc, &event->object);
+	NVIF_ERRON(ret, parent, "[NEW EVENT wait:%d size:%ld]", args->wait, argc - sizeof(*args));
+	if (ret)
+		return ret;
+
+	event->func = func;
+	return 0;
+}

drivers/gpu/drm/nouveau/nvkm/core/Kbuild

@@ -14,3 +14,4 @@ nvkm-y += nvkm/core/oproxy.o
 nvkm-y += nvkm/core/option.o
 nvkm-y += nvkm/core/ramht.o
 nvkm-y += nvkm/core/subdev.o
+nvkm-y += nvkm/core/uevent.o

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

@@ -44,7 +44,7 @@ nvkm_uclient_new(const struct nvkm_oclass *oclass, void *argv, u32 argc,
 	if (!(ret = nvif_unpack(ret, &argv, &argc, args->v0, 0, 0, false))){
 		args->v0.name[sizeof(args->v0.name) - 1] = 0;
 		ret = nvkm_client_new(args->v0.name, args->v0.device, NULL,
-				      NULL, oclass->client->ntfy, &client);
+				      NULL, oclass->client->ntfy, oclass->client->event, &client);
 		if (ret)
 			return ret;
 	} else
@@ -286,7 +286,7 @@ int
 nvkm_client_new(const char *name, u64 device, const char *cfg,
 		const char *dbg,
 		int (*ntfy)(const void *, u32, const void *, u32),
-		struct nvkm_client **pclient)
+		int (*event)(u64, void *, u32), struct nvkm_client **pclient)
 {
 	struct nvkm_oclass oclass = { .base = nvkm_uclient_sclass };
 	struct nvkm_client *client;
@@ -301,6 +301,7 @@ nvkm_client_new(const char *name, u64 device, const char *cfg,
 	client->debug = nvkm_dbgopt(dbg, "CLIENT");
 	client->objroot = RB_ROOT;
 	client->ntfy = ntfy;
+	client->event = event;
 	INIT_LIST_HEAD(&client->umem);
 	spin_lock_init(&client->lock);
 	return 0;