[RFC PATCH hwc] drm_hwcomposer: provide a common gralloc handle definition

[Robert Foss]

Hey Rob,

On Tue, 2017-10-24 at 18:40 -0500, Rob Herring wrote:
> EGL, gralloc, and HWC must all have a common definition of fd's and
> int's
> in native_handle_t to share the fd and width, height, format, etc.
> of a dmabuf.
> 
> Move the definition into HWC so we aren't dependent on a specific
> gralloc
> implementation and so we don't have to create an importer just for
> different native_handle_t layouts. This will allow supporting
> multiple
> gralloc implementations that conform to this layout.

I think this makes sense to me, and is an improvement over the current
situation.
As far as I can see there is no perfect way of doing this. But this is
definitely better.

> 
> Perhaps we should allow for multiple levels of subclassing by only
> defining
> the fields we care about here and not validating magic and the size.

So the idea with the subclassing would be for each gralloc
implementations to be able to add their special sauce?

> 
> Signed-off-by: Rob Herring <robh at kernel.org>
> ---
> I'm not sure if there's a better way, but I can't find a way to
> remove 
> the gralloc dependency. At least for EGL, only the fd is needed as
> it 
> has the ANativeWindow and can get all the info from that.
> 
> 
>  Android.mk           |  1 -
>  gralloc_drm_handle.h | 85
> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 85 insertions(+), 1 deletion(-)
>  create mode 100644 gralloc_drm_handle.h
> 
> diff --git a/Android.mk b/Android.mk
> index 611fcb75190b..ee5b8bfb44d0 100644
> --- a/Android.mk
> +++ b/Android.mk
> @@ -47,7 +47,6 @@ LOCAL_SHARED_LIBRARIES := \
>  LOCAL_STATIC_LIBRARIES := libdrmhwc_utils
>  
>  LOCAL_C_INCLUDES := \
> -	external/gbm_gralloc \
>  	system/core/libsync
>  
>  LOCAL_SRC_FILES := \
> diff --git a/gralloc_drm_handle.h b/gralloc_drm_handle.h
> new file mode 100644
> index 000000000000..aa89e46db619
> --- /dev/null
> +++ b/gralloc_drm_handle.h
> @@ -0,0 +1,85 @@
> +/*
> + * Copyright (C) 2010-2011 Chia-I Wu <olvaffe at gmail.com>
> + * Copyright (C) 2010-2011 LunarG Inc.
> + * Copyright (C) 2016 Linaro, Ltd., Rob Herring <robh at kernel.org>
> + *
> + * 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 AUTHORS OR COPYRIGHT HOLDERS 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.
> + */
> +
> +#ifndef _GRALLOC_DRM_HANDLE_H_
> +#define _GRALLOC_DRM_HANDLE_H_
> +
> +#include <cutils/native_handle.h>
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +struct gralloc_drm_handle_t {
> +	native_handle_t base;
> +
> +	/* file descriptors */
> +	int prime_fd;
> +
> +	/* integers */
> +	int magic;
> +
> +	int width;
> +	int height;
> +	int format;
> +	int usage;
> +	int stride; /* the stride in bytes */
> +	uint64_t modifier; /* buffer modifiers */
> +
> +	int data_owner; /* owner of data (for validation) */
> +	union {
> +		void *data; /* private pointer for gralloc */
> +		uint64_t reserved;
> +	} __attribute__((aligned(8)));
> +};
> +#define GRALLOC_HANDLE_MAGIC 0x5f47424d
> +#define GRALLOC_HANDLE_NUM_FDS 1
> +#define GRALLOC_HANDLE_NUM_INTS (					
> 	\
> +	((sizeof(struct gralloc_drm_handle_t) -
> sizeof(native_handle_t))/sizeof(int))	\
> +	 - GRALLOC_HANDLE_NUM_FDS)
> +
> +static inline struct gralloc_drm_handle_t
> *gralloc_drm_handle(buffer_handle_t _handle)
> +{
> +	struct gralloc_drm_handle_t *handle =
> +		(struct gralloc_drm_handle_t *) _handle;
> +
> +	if (handle && (handle->base.version != sizeof(handle->base)
> ||
> +	               handle->base.numInts !=
> GRALLOC_HANDLE_NUM_INTS ||
> +	               handle->base.numFds != GRALLOC_HANDLE_NUM_FDS
> ||
> +	               handle->magic != GRALLOC_HANDLE_MAGIC))
> +		return NULL;
> +
> +	return handle;
> +}
> +
> +static inline int gralloc_drm_get_prime_fd(buffer_handle_t _handle)
> +{
> +	struct gralloc_drm_handle_t *handle =
> gralloc_drm_handle(_handle);
> +	return (handle) ? handle->prime_fd : -1;
> +}
> +
> +#ifdef __cplusplus
> +}
> +#endif
> +#endif /* _GRALLOC_DRM_HANDLE_H_ */