On 10/10/2025 11:11, Boris Brezillon wrote:
> From: Faith Ekstrand <[email protected]>
> 
> This will be used by the UMD to synchronize CPU-cached mappings when
> the UMD can't do it directly (no usermode cache maintenance instruction
> on Arm32).
> 
> v2:
> - Add more to the commit message
> - Change the flags to better match the drm_gem_shmem_sync semantics
> 
> Signed-off-by: Faith Ekstrand <[email protected]>
> Signed-off-by: Boris Brezillon <[email protected]>

Reviewed-by: Steven Price <[email protected]>

> ---
>  drivers/gpu/drm/panfrost/panfrost_drv.c | 57 +++++++++++++++++++++++++
>  drivers/gpu/drm/panfrost/panfrost_gem.c | 20 +++++++++
>  drivers/gpu/drm/panfrost/panfrost_gem.h |  2 +
>  include/uapi/drm/panfrost_drm.h         | 47 ++++++++++++++++++++
>  4 files changed, 126 insertions(+)
> 
> diff --git a/drivers/gpu/drm/panfrost/panfrost_drv.c 
> b/drivers/gpu/drm/panfrost/panfrost_drv.c
> index 3ffcd08f7745..cabf544f0437 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_drv.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_drv.c
> @@ -579,6 +579,62 @@ static int panfrost_ioctl_jm_ctx_destroy(struct 
> drm_device *dev, void *data,
>       return panfrost_jm_ctx_destroy(file, args->handle);
>  }
>  
> +#define PANFROST_BO_SYNC_OP_FLAGS                               \
> +     (PANFROST_BO_SYNC_FOR_DEV | PANFROST_BO_SYNC_FOR_READ | \
> +      PANFROST_BO_SYNC_FOR_WRITE)
> +
> +static int panfrost_ioctl_sync_bo(struct drm_device *ddev, void *data,
> +                               struct drm_file *file)
> +{
> +     struct drm_panfrost_sync_bo *args = data;
> +     struct drm_panfrost_bo_sync_op *ops;
> +     struct drm_gem_object *obj;
> +     int ret;
> +     u32 i;
> +
> +     if (args->pad)
> +             return -EINVAL;
> +
> +     ops = kvmalloc_array(args->op_count, sizeof(*ops), GFP_KERNEL);
> +     if (!ops) {
> +             DRM_DEBUG("Failed to allocate incoming BO sync ops array\n");
> +             return -ENOMEM;
> +     }
> +
> +     if (copy_from_user(ops, (void __user *)(uintptr_t)args->ops,
> +                        args->op_count * sizeof(*ops))) {
> +             DRM_DEBUG("Failed to copy in BO sync ops\n");
> +             ret = -EFAULT;
> +             goto err_ops;
> +     }
> +
> +     for (i = 0; i < args->op_count; i++) {
> +             if (ops[i].flags & ~PANFROST_BO_SYNC_OP_FLAGS) {
> +                     ret = -EINVAL;
> +                     goto err_ops;
> +             }
> +
> +             obj = drm_gem_object_lookup(file, ops[i].handle);
> +             if (!obj) {
> +                     ret = -ENOENT;
> +                     goto err_ops;
> +             }
> +
> +             ret = panfrost_gem_sync(obj, ops[i].flags,
> +                                     ops[i].offset, ops[i].size);
> +
> +             drm_gem_object_put(obj);
> +
> +             if (ret)
> +                     goto err_ops;
> +     }
> +
> +err_ops:
> +     kvfree(ops);
> +
> +     return ret;
> +}
> +
>  int panfrost_unstable_ioctl_check(void)
>  {
>       if (!unstable_ioctls)
> @@ -648,6 +704,7 @@ static const struct drm_ioctl_desc 
> panfrost_drm_driver_ioctls[] = {
>       PANFROST_IOCTL(SET_LABEL_BO,    set_label_bo,   DRM_RENDER_ALLOW),
>       PANFROST_IOCTL(JM_CTX_CREATE,   jm_ctx_create,  DRM_RENDER_ALLOW),
>       PANFROST_IOCTL(JM_CTX_DESTROY,  jm_ctx_destroy, DRM_RENDER_ALLOW),
> +     PANFROST_IOCTL(SYNC_BO,         sync_bo,        DRM_RENDER_ALLOW),
>  };
>  
>  static void panfrost_gpu_show_fdinfo(struct panfrost_device *pfdev,
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.c 
> b/drivers/gpu/drm/panfrost/panfrost_gem.c
> index 85d6289a6eda..da0362202d94 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.c
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.c
> @@ -365,6 +365,26 @@ panfrost_gem_set_label(struct drm_gem_object *obj, const 
> char *label)
>       kfree_const(old_label);
>  }
>  
> +int
> +panfrost_gem_sync(struct drm_gem_object *obj, u32 flags,
> +               u32 offset, u32 size)
> +{
> +     struct panfrost_gem_object *bo = to_panfrost_bo(obj);
> +     enum drm_gem_object_access_flags gem_access_flags = 0;
> +
> +     if (flags & PANFROST_BO_SYNC_FOR_DEV)
> +             gem_access_flags |= DRM_GEM_OBJECT_DEV_ACCESS;
> +     else
> +             gem_access_flags |= DRM_GEM_OBJECT_CPU_ACCESS;
> +
> +     if (flags & PANFROST_BO_SYNC_FOR_READ)
> +             gem_access_flags |= DRM_GEM_OBJECT_READ_ACCESS;
> +     if (flags & PANFROST_BO_SYNC_FOR_WRITE)
> +             gem_access_flags |= DRM_GEM_OBJECT_WRITE_ACCESS;
> +
> +     return drm_gem_shmem_sync(&bo->base, offset, size, gem_access_flags);
> +}
> +
>  void
>  panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char 
> *label)
>  {
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h 
> b/drivers/gpu/drm/panfrost/panfrost_gem.h
> index 8de3e76f2717..6a0e090aa59b 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
> @@ -148,6 +148,8 @@ int panfrost_gem_shrinker_init(struct drm_device *dev);
>  void panfrost_gem_shrinker_cleanup(struct drm_device *dev);
>  
>  void panfrost_gem_set_label(struct drm_gem_object *obj, const char *label);
> +int panfrost_gem_sync(struct drm_gem_object *obj, u32 flags,
> +                   u32 offset, u32 size);
>  void panfrost_gem_internal_set_label(struct drm_gem_object *obj, const char 
> *label);
>  
>  #ifdef CONFIG_DEBUG_FS
> diff --git a/include/uapi/drm/panfrost_drm.h b/include/uapi/drm/panfrost_drm.h
> index d3f6c005463c..fcc9f930df5f 100644
> --- a/include/uapi/drm/panfrost_drm.h
> +++ b/include/uapi/drm/panfrost_drm.h
> @@ -24,6 +24,7 @@ extern "C" {
>  #define DRM_PANFROST_SET_LABEL_BO            0x09
>  #define DRM_PANFROST_JM_CTX_CREATE           0x0a
>  #define DRM_PANFROST_JM_CTX_DESTROY          0x0b
> +#define DRM_PANFROST_SYNC_BO                 0x0c
>  
>  #define DRM_IOCTL_PANFROST_SUBMIT            DRM_IOW(DRM_COMMAND_BASE + 
> DRM_PANFROST_SUBMIT, struct drm_panfrost_submit)
>  #define DRM_IOCTL_PANFROST_WAIT_BO           DRM_IOW(DRM_COMMAND_BASE + 
> DRM_PANFROST_WAIT_BO, struct drm_panfrost_wait_bo)
> @@ -35,6 +36,7 @@ extern "C" {
>  #define DRM_IOCTL_PANFROST_SET_LABEL_BO              
> DRM_IOWR(DRM_COMMAND_BASE + DRM_PANFROST_SET_LABEL_BO, struct 
> drm_panfrost_set_label_bo)
>  #define DRM_IOCTL_PANFROST_JM_CTX_CREATE     DRM_IOWR(DRM_COMMAND_BASE + 
> DRM_PANFROST_JM_CTX_CREATE, struct drm_panfrost_jm_ctx_create)
>  #define DRM_IOCTL_PANFROST_JM_CTX_DESTROY    DRM_IOWR(DRM_COMMAND_BASE + 
> DRM_PANFROST_JM_CTX_DESTROY, struct drm_panfrost_jm_ctx_destroy)
> +#define DRM_IOCTL_PANFROST_SYNC_BO           DRM_IOWR(DRM_COMMAND_BASE + 
> DRM_PANFROST_SYNC_BO, struct drm_panfrost_sync_bo)
>  
>  /*
>   * Unstable ioctl(s): only exposed when the unsafe unstable_ioctls module
> @@ -266,6 +268,51 @@ struct drm_panfrost_set_label_bo {
>       __u64 label;
>  };
>  
> +/* Valid flags to pass to drm_panfrost_bo_sync_op */
> +#define PANFROST_BO_SYNC_FOR_CPU     (0 << 0)
> +#define PANFROST_BO_SYNC_FOR_DEV     (1 << 0)
> +#define PANFROST_BO_SYNC_FOR_READ    (1 << 1)
> +#define PANFROST_BO_SYNC_FOR_WRITE   (1 << 2)
> +
> +/**
> + * struct drm_panthor_bo_flush_map_op - BO map sync op
> + */
> +struct drm_panfrost_bo_sync_op {
> +     /** @handle: Handle of the buffer object to sync. */
> +     __u32 handle;
> +
> +     /** @flags: Flags controlling the sync operation. */
> +     __u32 flags;
> +
> +     /**
> +      * @offset: Offset into the BO at which the sync range starts.
> +      *
> +      * This will be rounded down to the nearest cache line as needed.
> +      */
> +     __u32 offset;
> +
> +     /**
> +      * @size: Size of the range to sync
> +      *
> +      * @size + @offset will be rounded up to the nearest cache line as
> +      * needed.
> +      */
> +     __u32 size;
> +};
> +
> +/**
> + * struct drm_panfrost_sync_bo - ioctl argument for syncing BO maps
> + */
> +struct drm_panfrost_sync_bo {
> +     /** Array of struct drm_panfrost_bo_sync_op */
> +     __u64 ops;
> +
> +     /** Number of BO sync ops */
> +     __u32 op_count;
> +
> +     __u32 pad;
> +};
> +
>  /* Definitions for coredump decoding in user space */
>  #define PANFROSTDUMP_MAJOR 1
>  #define PANFROSTDUMP_MINOR 0

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