drm/nouveau/falcon: protect against concurrent DMEM accesses

The falcon library may be used concurrently, especially after the
introduction of the msgqueue interface. Make it safe to use it that way.

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/include/nvkm/engine/falcon.h b/drivers/gpu/drm/nouveau/include/nvkm/engine/falcon.h
index 7e498e6..9384dff 100644 (file)
--- a/drivers/gpu/drm/nouveau/include/nvkm/engine/falcon.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/engine/falcon.h
@@ -19,6 +19,7 @@ struct nvkm_falcon {
        u32 addr;
 
        struct mutex mutex;
+       struct mutex dmem_mutex;
        const struct nvkm_subdev *user;
 
        u8 version;

diff --git a/drivers/gpu/drm/nouveau/nvkm/falcon/base.c b/drivers/gpu/drm/nouveau/nvkm/falcon/base.c
index 4852f31..ee25fdc 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/falcon/base.c
+++ b/drivers/gpu/drm/nouveau/nvkm/falcon/base.c
@@ -41,14 +41,22 @@ void
 nvkm_falcon_load_dmem(struct nvkm_falcon *falcon, void *data, u32 start,
                      u32 size, u8 port)
 {
+       mutex_lock(&falcon->dmem_mutex);
+
        falcon->func->load_dmem(falcon, data, start, size, port);
+
+       mutex_unlock(&falcon->dmem_mutex);
 }
 
 void
 nvkm_falcon_read_dmem(struct nvkm_falcon *falcon, u32 start, u32 size, u8 port,
                      void *data)
 {
+       mutex_lock(&falcon->dmem_mutex);
+
        falcon->func->read_dmem(falcon, start, size, port, data);
+
+       mutex_unlock(&falcon->dmem_mutex);
 }
 
 void
@@ -166,6 +174,7 @@ nvkm_falcon_ctor(const struct nvkm_falcon_func *func,
        falcon->name = name;
        falcon->addr = addr;
        mutex_init(&falcon->mutex);
+       mutex_init(&falcon->dmem_mutex);
 
        reg = nvkm_falcon_rd32(falcon, 0x12c);
        falcon->version = reg & 0xf;