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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* drm gem CMA (contiguous memory allocator) helper functions
*
* Copyright (C) 2012 Sascha Hauer, Pengutronix
*
* Based on Samsung Exynos code
*
* Copyright (c) 2011 Samsung Electronics Co., Ltd.
*/
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/export.h>
#include <linux/dma-buf.h>
#include <linux/dma-mapping.h>
#include <drm/drmP.h>
#include <drm/drm.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_vma_manager.h>
/**
* DOC: cma helpers
*
* The Contiguous Memory Allocator reserves a pool of memory at early boot
* that is used to service requests for large blocks of contiguous memory.
*
* The DRM GEM/CMA helpers use this allocator as a means to provide buffer
* objects that are physically contiguous in memory. This is useful for
* display drivers that are unable to map scattered buffers via an IOMMU.
*/
/**
* __drm_gem_cma_create - Create a GEM CMA object without allocating memory
* @drm: DRM device
* @size: size of the object to allocate
*
* This function creates and initializes a GEM CMA object of the given size,
* but doesn't allocate any memory to back the object.
*
* Returns:
* A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
* error code on failure.
*/
static struct drm_gem_cma_object *
__drm_gem_cma_create(struct drm_device *drm, size_t size)
{
struct drm_gem_cma_object *cma_obj;
struct drm_gem_object *gem_obj;
int ret;
if (drm->driver->gem_create_object)
gem_obj = drm->driver->gem_create_object(drm, size);
else
gem_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
if (!gem_obj)
return ERR_PTR(-ENOMEM);
cma_obj = container_of(gem_obj, struct drm_gem_cma_object, base);
ret = drm_gem_object_init(drm, gem_obj, size);
if (ret)
goto error;
ret = drm_gem_create_mmap_offset(gem_obj);
if (ret) {
drm_gem_object_release(gem_obj);
goto error;
}
return cma_obj;
error:
kfree(cma_obj);
return ERR_PTR(ret);
}
/**
* drm_gem_cma_create - allocate an object with the given size
* @drm: DRM device
* @size: size of the object to allocate
*
* This function creates a CMA GEM object and allocates a contiguous chunk of
* memory as backing store. The backing memory has the writecombine attribute
* set.
*
* Returns:
* A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
* error code on failure.
*/
struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
size_t size)
{
struct drm_gem_cma_object *cma_obj;
int ret;
size = round_up(size, PAGE_SIZE);
cma_obj = __drm_gem_cma_create(drm, size);
if (IS_ERR(cma_obj))
return cma_obj;
cma_obj->vaddr = dma_alloc_wc(drm->dev, size, &cma_obj->paddr,
GFP_KERNEL | __GFP_NOWARN);
if (!cma_obj->vaddr) {
dev_dbg(drm->dev, "failed to allocate buffer with size %zu\n",
size);
ret = -ENOMEM;
goto error;
}
return cma_obj;
error:
drm_gem_object_put_unlocked(&cma_obj->base);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_create);
/**
* drm_gem_cma_create_with_handle - allocate an object with the given size and
* return a GEM handle to it
* @file_priv: DRM file-private structure to register the handle for
* @drm: DRM device
* @size: size of the object to allocate
* @handle: return location for the GEM handle
*
* This function creates a CMA GEM object, allocating a physically contiguous
* chunk of memory as backing store. The GEM object is then added to the list
* of object associated with the given file and a handle to it is returned.
*
* Returns:
* A struct drm_gem_cma_object * on success or an ERR_PTR()-encoded negative
* error code on failure.
*/
static struct drm_gem_cma_object *
drm_gem_cma_create_with_handle(struct drm_file *file_priv,
struct drm_device *drm, size_t size,
uint32_t *handle)
{
struct drm_gem_cma_object *cma_obj;
struct drm_gem_object *gem_obj;
int ret;
cma_obj = drm_gem_cma_create(drm, size);
if (IS_ERR(cma_obj))
return cma_obj;
gem_obj = &cma_obj->base;
/*
* allocate a id of idr table where the obj is registered
* and handle has the id what user can see.
*/
ret = drm_gem_handle_create(file_priv, gem_obj, handle);
/* drop reference from allocate - handle holds it now. */
drm_gem_object_put_unlocked(gem_obj);
if (ret)
return ERR_PTR(ret);
return cma_obj;
}
/**
* drm_gem_cma_free_object - free resources associated with a CMA GEM object
* @gem_obj: GEM object to free
*
* This function frees the backing memory of the CMA GEM object, cleans up the
* GEM object state and frees the memory used to store the object itself.
* If the buffer is imported and the virtual address is set, it is released.
* Drivers using the CMA helpers should set this as their
* &drm_driver.gem_free_object_unlocked callback.
*/
void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
{
struct drm_gem_cma_object *cma_obj;
cma_obj = to_drm_gem_cma_obj(gem_obj);
if (gem_obj->import_attach) {
if (cma_obj->vaddr)
dma_buf_vunmap(gem_obj->import_attach->dmabuf, cma_obj->vaddr);
drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
} else if (cma_obj->vaddr) {
dma_free_wc(gem_obj->dev->dev, cma_obj->base.size,
cma_obj->vaddr, cma_obj->paddr);
}
drm_gem_object_release(gem_obj);
kfree(cma_obj);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_free_object);
/**
* drm_gem_cma_dumb_create_internal - create a dumb buffer object
* @file_priv: DRM file-private structure to create the dumb buffer for
* @drm: DRM device
* @args: IOCTL data
*
* This aligns the pitch and size arguments to the minimum required. This is
* an internal helper that can be wrapped by a driver to account for hardware
* with more specific alignment requirements. It should not be used directly
* as their &drm_driver.dumb_create callback.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_cma_dumb_create_internal(struct drm_file *file_priv,
struct drm_device *drm,
struct drm_mode_create_dumb *args)
{
unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
struct drm_gem_cma_object *cma_obj;
if (args->pitch < min_pitch)
args->pitch = min_pitch;
if (args->size < args->pitch * args->height)
args->size = args->pitch * args->height;
cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
&args->handle);
return PTR_ERR_OR_ZERO(cma_obj);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create_internal);
/**
* drm_gem_cma_dumb_create - create a dumb buffer object
* @file_priv: DRM file-private structure to create the dumb buffer for
* @drm: DRM device
* @args: IOCTL data
*
* This function computes the pitch of the dumb buffer and rounds it up to an
* integer number of bytes per pixel. Drivers for hardware that doesn't have
* any additional restrictions on the pitch can directly use this function as
* their &drm_driver.dumb_create callback.
*
* For hardware with additional restrictions, drivers can adjust the fields
* set up by userspace and pass the IOCTL data along to the
* drm_gem_cma_dumb_create_internal() function.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_cma_dumb_create(struct drm_file *file_priv,
struct drm_device *drm,
struct drm_mode_create_dumb *args)
{
struct drm_gem_cma_object *cma_obj;
args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
args->size = args->pitch * args->height;
cma_obj = drm_gem_cma_create_with_handle(file_priv, drm, args->size,
&args->handle);
return PTR_ERR_OR_ZERO(cma_obj);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_create);
const struct vm_operations_struct drm_gem_cma_vm_ops = {
.open = drm_gem_vm_open,
.close = drm_gem_vm_close,
};
EXPORT_SYMBOL_GPL(drm_gem_cma_vm_ops);
static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj,
struct vm_area_struct *vma)
{
int ret;
/*
* Clear the VM_PFNMAP flag that was set by drm_gem_mmap(), and set the
* vm_pgoff (used as a fake buffer offset by DRM) to 0 as we want to map
* the whole buffer.
*/
vma->vm_flags &= ~VM_PFNMAP;
vma->vm_pgoff = 0;
ret = dma_mmap_wc(cma_obj->base.dev->dev, vma, cma
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