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drm/vram-helpers: Merge code into a single file 

Most of the documentation was in an otherwise empty file, which was
probably just left from a previous clean-up effort. So move code and
documentation into a single file.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200331081238.24749-1-tzimmermann@suse.de
This commit is contained in:
Thomas Zimmermann 2020-03-31 10:12:38 +02:00
parent d7b001d852
commit b22b51a034
4 changed files with 91 additions and 110 deletions
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9
Documentation/gpu/drm-mm.rst
View File

@ -373,15 +373,6 @@ GEM CMA Helper Functions Reference
.. kernel-doc:: drivers/gpu/drm/drm_gem_cma_helper.c
:export:
VRAM Helper Function Reference
==============================
.. kernel-doc:: drivers/gpu/drm/drm_vram_helper_common.c
:doc: overview
.. kernel-doc:: include/drm/drm_gem_vram_helper.h
:internal:
GEM VRAM Helper Functions Reference
-----------------------------------

3
drivers/gpu/drm/Makefile
View File

@ -33,8 +33,7 @@ drm-$(CONFIG_PCI) += drm_pci.o
drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
drm_vram_helper-y := drm_gem_vram_helper.o \
drm_vram_helper_common.o
drm_vram_helper-y := drm_gem_vram_helper.o
obj-$(CONFIG_DRM_VRAM_HELPER) += drm_vram_helper.o
drm_ttm_helper-y := drm_gem_ttm_helper.o

95
drivers/gpu/drm/drm_gem_vram_helper.c
View File

@ -1,5 +1,7 @@
// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/module.h>
#include <drm/drm_debugfs.h>
#include <drm/drm_device.h>
#include <drm/drm_drv.h>
@ -19,13 +21,93 @@ static const struct drm_gem_object_funcs drm_gem_vram_object_funcs;
/**
* DOC: overview
*
* This library provides a GEM buffer object that is backed by video RAM
* (VRAM). It can be used for framebuffer devices with dedicated memory.
* This library provides &struct drm_gem_vram_object (GEM VRAM), a GEM
* buffer object that is backed by video RAM (VRAM). It can be used for
* framebuffer devices with dedicated memory.
*
* The data structure &struct drm_vram_mm and its helpers implement a memory
* manager for simple framebuffer devices with dedicated video memory. Buffer
* objects are either placed in video RAM or evicted to system memory. The rsp.
* buffer object is provided by &struct drm_gem_vram_object.
* manager for simple framebuffer devices with dedicated video memory. GEM
* VRAM buffer objects are either placed in the video memory or remain evicted
* to system memory.
*
* With the GEM interface userspace applications create, manage and destroy
* graphics buffers, such as an on-screen framebuffer. GEM does not provide
* an implementation of these interfaces. It's up to the DRM driver to
* provide an implementation that suits the hardware. If the hardware device
* contains dedicated video memory, the DRM driver can use the VRAM helper
* library. Each active buffer object is stored in video RAM. Active
* buffer are used for drawing the current frame, typically something like
* the frame's scanout buffer or the cursor image. If there's no more space
* left in VRAM, inactive GEM objects can be moved to system memory.
*
* The easiest way to use the VRAM helper library is to call
* drm_vram_helper_alloc_mm(). The function allocates and initializes an
* instance of &struct drm_vram_mm in &struct drm_device.vram_mm . Use
* &DRM_GEM_VRAM_DRIVER to initialize &struct drm_driver and
* &DRM_VRAM_MM_FILE_OPERATIONS to initialize &struct file_operations;
* as illustrated below.
*
* .. code-block:: c
*
* struct file_operations fops ={
* .owner = THIS_MODULE,
* DRM_VRAM_MM_FILE_OPERATION
* };
* struct drm_driver drv = {
* .driver_feature = DRM_ ... ,
* .fops = &fops,
* DRM_GEM_VRAM_DRIVER
* };
*
* int init_drm_driver()
* {
* struct drm_device *dev;
* uint64_t vram_base;
* unsigned long vram_size;
* int ret;
*
* // setup device, vram base and size
* // ...
*
* ret = drm_vram_helper_alloc_mm(dev, vram_base, vram_size);
* if (ret)
* return ret;
* return 0;
* }
*
* This creates an instance of &struct drm_vram_mm, exports DRM userspace
* interfaces for GEM buffer management and initializes file operations to
* allow for accessing created GEM buffers. With this setup, the DRM driver
* manages an area of video RAM with VRAM MM and provides GEM VRAM objects
* to userspace.
*
* To clean up the VRAM memory management, call drm_vram_helper_release_mm()
* in the driver's clean-up code.
*
* .. code-block:: c
*
* void fini_drm_driver()
* {
* struct drm_device *dev = ...;
*
* drm_vram_helper_release_mm(dev);
* }
*
* For drawing or scanout operations, buffer object have to be pinned in video
* RAM. Call drm_gem_vram_pin() with &DRM_GEM_VRAM_PL_FLAG_VRAM or
* &DRM_GEM_VRAM_PL_FLAG_SYSTEM to pin a buffer object in video RAM or system
* memory. Call drm_gem_vram_unpin() to release the pinned object afterwards.
*
* A buffer object that is pinned in video RAM has a fixed address within that
* memory region. Call drm_gem_vram_offset() to retrieve this value. Typically
* it's used to program the hardware's scanout engine for framebuffers, set
* the cursor overlay's image for a mouse cursor, or use it as input to the
* hardware's draing engine.
*
* To access a buffer object's memory from the DRM driver, call
* drm_gem_vram_kmap(). It (optionally) maps the buffer into kernel address
* space and returns the memory address. Use drm_gem_vram_kunmap() to
* release the mapping.
*/
/*
@ -1197,3 +1279,6 @@ drm_vram_helper_mode_valid(struct drm_device *dev,
return drm_vram_helper_mode_valid_internal(dev, mode, max_bpp);
}
EXPORT_SYMBOL(drm_vram_helper_mode_valid);
MODULE_DESCRIPTION("DRM VRAM memory-management helpers");
MODULE_LICENSE("GPL");

94
drivers/gpu/drm/drm_vram_helper_common.c
View File

@ -1,94 +0,0 @@
// SPDX-License-Identifier: GPL-2.0-or-later
#include <linux/module.h>
/**
* DOC: overview
*
* This library provides &struct drm_gem_vram_object (GEM VRAM), a GEM
* buffer object that is backed by video RAM. It can be used for
* framebuffer devices with dedicated memory. The video RAM is managed
* by &struct drm_vram_mm (VRAM MM).
*
* With the GEM interface userspace applications create, manage and destroy
* graphics buffers, such as an on-screen framebuffer. GEM does not provide
* an implementation of these interfaces. It's up to the DRM driver to
* provide an implementation that suits the hardware. If the hardware device
* contains dedicated video memory, the DRM driver can use the VRAM helper
* library. Each active buffer object is stored in video RAM. Active
* buffer are used for drawing the current frame, typically something like
* the frame's scanout buffer or the cursor image. If there's no more space
* left in VRAM, inactive GEM objects can be moved to system memory.
*
* The easiest way to use the VRAM helper library is to call
* drm_vram_helper_alloc_mm(). The function allocates and initializes an
* instance of &struct drm_vram_mm in &struct drm_device.vram_mm . Use
* &DRM_GEM_VRAM_DRIVER to initialize &struct drm_driver and
* &DRM_VRAM_MM_FILE_OPERATIONS to initialize &struct file_operations;
* as illustrated below.
*
* .. code-block:: c
*
* struct file_operations fops ={
* .owner = THIS_MODULE,
* DRM_VRAM_MM_FILE_OPERATION
* };
* struct drm_driver drv = {
* .driver_feature = DRM_ ... ,
* .fops = &fops,
* DRM_GEM_VRAM_DRIVER
* };
*
* int init_drm_driver()
* {
* struct drm_device *dev;
* uint64_t vram_base;
* unsigned long vram_size;
* int ret;
*
* // setup device, vram base and size
* // ...
*
* ret = drm_vram_helper_alloc_mm(dev, vram_base, vram_size);
* if (ret)
* return ret;
* return 0;
* }
*
* This creates an instance of &struct drm_vram_mm, exports DRM userspace
* interfaces for GEM buffer management and initializes file operations to
* allow for accessing created GEM buffers. With this setup, the DRM driver
* manages an area of video RAM with VRAM MM and provides GEM VRAM objects
* to userspace.
*
* To clean up the VRAM memory management, call drm_vram_helper_release_mm()
* in the driver's clean-up code.
*
* .. code-block:: c
*
* void fini_drm_driver()
* {
* struct drm_device *dev = ...;
*
* drm_vram_helper_release_mm(dev);
* }
*
* For drawing or scanout operations, buffer object have to be pinned in video
* RAM. Call drm_gem_vram_pin() with &DRM_GEM_VRAM_PL_FLAG_VRAM or
* &DRM_GEM_VRAM_PL_FLAG_SYSTEM to pin a buffer object in video RAM or system
* memory. Call drm_gem_vram_unpin() to release the pinned object afterwards.
*
* A buffer object that is pinned in video RAM has a fixed address within that
* memory region. Call drm_gem_vram_offset() to retrieve this value. Typically
* it's used to program the hardware's scanout engine for framebuffers, set
* the cursor overlay's image for a mouse cursor, or use it as input to the
* hardware's draing engine.
*
* To access a buffer object's memory from the DRM driver, call
* drm_gem_vram_kmap(). It (optionally) maps the buffer into kernel address
* space and returns the memory address. Use drm_gem_vram_kunmap() to
* release the mapping.
*/
MODULE_DESCRIPTION("DRM VRAM memory-management helpers");
MODULE_LICENSE("GPL");