Mesa (master): gbm: Add documentation for the public facing API
Kristian Høgsberg
krh at kemper.freedesktop.org
Fri Jan 13 14:32:05 UTC 2012
Module: Mesa
Branch: master
Commit: baab68e1a607b818c8988e70546fe3e6f97cf572
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=baab68e1a607b818c8988e70546fe3e6f97cf572
Author: Rob Bradford <rob at linux.intel.com>
Date: Tue Dec 20 15:40:21 2011 +0000
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 8440b2c..3e24c4a 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 05d2292..c4ae51d 100644
--- a/src/gbm/main/gbm.h
+++ b/src/gbm/main/gbm.h
@@ -37,9 +37,28 @@ extern "C" {
#include <stdint.h>
+/**
+ * \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 fb8db80..9e4072e 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;
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