From baab68e1a607b818c8988e70546fe3e6f97cf572 Mon Sep 17 00:00:00 2001 From: Rob Bradford Date: Tue, 20 Dec 2011 15:40:21 +0000 Subject: [PATCH] gbm: Add documentation for the public facing API --- src/gbm/main/gbm.c | 104 ++++++++++++++++++++++++++++++++++++++++++ src/gbm/main/gbm.h | 45 +++++++++++++++++- src/gbm/main/gbmint.h | 15 ++++++ 3 files changed, 162 insertions(+), 2 deletions(-) diff --git a/src/gbm/main/gbm.c b/src/gbm/main/gbm.c index 8440b2c6ae3..3e24c4af011 100644 --- a/src/gbm/main/gbm.c +++ b/src/gbm/main/gbm.c @@ -48,6 +48,10 @@ struct gbm_device *devices[16]; static int device_num = 0; +/** Returns the file description for the gbm device + * + * \return The fd that the struct gbm_device was created with + */ GBM_EXPORT int gbm_device_get_fd(struct gbm_device *gbm) { @@ -55,12 +59,29 @@ gbm_device_get_fd(struct gbm_device *gbm) } /* FIXME: maybe superfluous, use udev subclass from the fd? */ +/** Get the backend name for the given gbm device + * + * \return The backend name string - this belongs to the device and must not + * be freed + */ GBM_EXPORT const char * gbm_device_get_backend_name(struct gbm_device *gbm) { return gbm->name; } +/** Test if a format is supported for a given set of usage flags. + * + * \param gbm The created buffer manager + * \param format The format to test + * \param usage A bitmask of the usages to test the format against + * \return 1 if the format is supported otherwise 0 + * + * \sa enum gbm_bo_flags for the list of flags that the format can be + * tested against + * + * \sa enum gbm_bo_format for the list of formats + */ int gbm_device_is_format_supported(struct gbm_device *gbm, enum gbm_bo_format format, @@ -69,6 +90,10 @@ gbm_device_is_format_supported(struct gbm_device *gbm, return gbm->is_format_supported(gbm, format, usage); } +/** Destroy the gbm device and free all resources associated with it. + * + * \param gbm The device created using gbm_create_device() + */ GBM_EXPORT void gbm_device_destroy(struct gbm_device *gbm) { @@ -103,6 +128,18 @@ _gbm_mesa_get_device(int fd) return gbm; } +/** Create a gbm device for allocating buffers + * + * The file descriptor passed in is used by the backend to communicate with + * platform for allocating the memory. For allocations using DRI this would be + * the file descriptor returned when opening a device such as \c + * /dev/dri/card0 + * + * \param fd The file descriptor for an backend specific device + * \return The newly created struct gbm_device. The resources associated with + * the device should be freed with gbm_device_destroy() when it is no longer + * needed. If the creation of the device failed NULL will be returned. + */ GBM_EXPORT struct gbm_device * gbm_create_device(int fd) { @@ -131,36 +168,85 @@ gbm_create_device(int fd) return gbm; } +/** Get the width of the buffer object + * + * \param bo The buffer object + * \return The width of the allocated buffer object + * + */ GBM_EXPORT unsigned int gbm_bo_get_width(struct gbm_bo *bo) { return bo->width; } +/** Get the height of the buffer object + * + * \param bo The buffer object + * \return The height of the allocated buffer object + */ GBM_EXPORT unsigned int gbm_bo_get_height(struct gbm_bo *bo) { return bo->height; } +/** Get the stride of the buffer object + * + * This is calculated by the backend when it does the allocation in + * gbm_bo_create() + * + * \param bo The buffer object + * \return The stride of the allocated buffer object + */ GBM_EXPORT uint32_t gbm_bo_get_pitch(struct gbm_bo *bo) { return bo->pitch; } +/** Get the handle of the buffer object + * + * This is stored in the platform generic union gbm_bo_handle type. However + * the format of this handle is platform specific. + * + * \param bo The buffer object + * \return Returns the stride of the allocated buffer object + */ GBM_EXPORT union gbm_bo_handle gbm_bo_get_handle(struct gbm_bo *bo) { return bo->handle; } +/** + * Destroys the given buffer object and frees all resources associated with + * it. + * + * \param bo The buffer object + */ GBM_EXPORT void gbm_bo_destroy(struct gbm_bo *bo) { bo->gbm->bo_destroy(bo); } +/** + * Allocate a buffer object for the given dimensions + * + * \param gbm The gbm device returned from gbm_create_device() + * \param width The width for the buffer + * \param height The height for the buffer + * \param format The format to use for the buffer + * \param usage The union of the usage flags for this buffer + * + * \return A newly allocated buffer that should be freed with gbm_bo_destroy() + * when no longer needed. If an error occurs during allocation %NULL will be + * returned. + * + * \sa enum gbm_bo_format for the list of formats + * \sa enum gbm_bo_flags for the list of usage flags + */ GBM_EXPORT struct gbm_bo * gbm_bo_create(struct gbm_device *gbm, uint32_t width, uint32_t height, @@ -176,6 +262,24 @@ gbm_bo_create(struct gbm_device *gbm, return gbm->bo_create(gbm, width, height, format, usage); } +/** + * Create a buffer object representing the contents of an EGLImage + * + * \param gbm The gbm device returned from gbm_create_device() + * \param egl_dpy The EGLDisplay on which the EGLImage was created + * \param egl_image The EGLImage to create the buffer from + * \param width The width to use in the creation of the buffer object + * \param height The height to use in the creation of the buffer object + * \param usage The union of the usage flags for this buffer + * + * \return A newly allocated buffer object that should be freed with + * gbm_bo_destroy() when no longer needed. + * + * \sa enum gbm_bo_flags for the list of usage flags + * + * \note The expectation is that this function will use an efficient method + * for making the contents of the EGLImage available as a buffer object. + */ GBM_EXPORT struct gbm_bo * gbm_bo_create_from_egl_image(struct gbm_device *gbm, void *egl_dpy, void *egl_image, diff --git a/src/gbm/main/gbm.h b/src/gbm/main/gbm.h index 05d2292dc75..c4ae51db022 100644 --- a/src/gbm/main/gbm.h +++ b/src/gbm/main/gbm.h @@ -37,9 +37,28 @@ extern "C" { #include +/** + * \file gbm.h + * \brief Generic Buffer Manager + */ + struct gbm_device; struct gbm_bo; +/** + * \mainpage The Generic Buffer Manager + * + * This module provides an abstraction that the caller can use to request a + * buffer from the underlying memory management system for the platform. + * + * This allows the creation of portable code whilst still allowing access to + * the underlying memory manager. + */ + +/** + * Abstraction representing the handle to a buffer allocated by the + * manager + */ union gbm_bo_handle { void *ptr; int32_t s32; @@ -48,14 +67,36 @@ union gbm_bo_handle { uint64_t u64; }; +/** Format of the allocated buffer */ enum gbm_bo_format { - GBM_BO_FORMAT_XRGB8888, - GBM_BO_FORMAT_ARGB8888, + /** RGB with 8 bits per channel in a 32 bit value */ + GBM_BO_FORMAT_XRGB8888, + /** ARGB with 8 bits per channel in a 32 bit value */ + GBM_BO_FORMAT_ARGB8888 }; +/** + * Flags to indicate the intended use for the buffer - these are passed into + * gbm_bo_create(). The caller must set the union of all the flags that are + * appropriate + * + * \sa Use gbm_device_is_format_supported() to check if the combination of format + * and use flags are supported + */ enum gbm_bo_flags { + /** + * Buffer is going to be presented to the screen using an API such as KMS + */ GBM_BO_USE_SCANOUT = (1 << 0), + /** + * Buffer is going to be used as cursor - the dimensions for the buffer + * must be 64x64 if this flag is passed. + */ GBM_BO_USE_CURSOR_64X64 = (1 << 1), + /** + * Buffer is to be used for rendering - for example it is going to be used + * as the storage for a color buffer + */ GBM_BO_USE_RENDERING = (1 << 2), }; diff --git a/src/gbm/main/gbmint.h b/src/gbm/main/gbmint.h index fb8db804c1b..9e4072ef6ea 100644 --- a/src/gbm/main/gbmint.h +++ b/src/gbm/main/gbmint.h @@ -38,6 +38,16 @@ #define GBM_EXPORT #endif +/** + * \file gbmint.h + * \brief Internal implementation details of gbm + */ + +/** + * The device used for the memory allocation. + * + * The members of this structure should be not accessed directly + */ struct gbm_device { /* Hack to make a gbm_device detectable by its first element. */ struct gbm_device *(*dummy)(int); @@ -63,6 +73,11 @@ struct gbm_device { void (*bo_destroy)(struct gbm_bo *bo); }; +/** + * The allocated buffer object. + * + * The members in this structure should not be accessed directly. + */ struct gbm_bo { struct gbm_device *gbm; uint32_t width; -- 2.30.2