/*
* 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.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#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;
cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
if (!cma_obj)
return ERR_PTR(-ENOMEM);
gem_obj = &cma_obj->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_writecombine(drm->dev, size,
&cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
if (!cma_obj->vaddr) {
dev_err(drm->dev, "failed to allocate buffer with size %zu\n",
size);
ret = -ENOMEM;
goto error;
}
return cma_obj;
error:
drm_gem_cma_free_object(&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);
if (ret)
goto err_handle_create;
/* drop reference from allocate - handle holds it now. */
drm_gem_object_unreference_unlocked(gem_obj);
return cma_obj;
err_handle_create:
drm_gem_cma_free_object(gem_obj);
return ERR_PTR(ret);
}
/**
* 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.
* Drivers using the CMA helpers should set this as their DRM driver's
* ->gem_free_object() 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 (cma_obj->vaddr) {
dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
cma_obj->vaddr, cma_obj->paddr);
} else if (gem_obj->import_attach) {
drm_prime_gem_destroy(gem_obj, cma_obj->sgt);
}
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 the ->dumb_create() callback in a DRM driver.
*
* 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 ->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);
/**
* drm_gem_cma_dumb_map_offset - return the fake mmap offset for a CMA GEM
* object
* @file_priv: DRM file-private structure containing the GEM object
* @drm: DRM device
* @handle: GEM object handle
* @offset: return location for the fake mmap offset
*
* This function look up an object by its handle and returns the fake mmap
* offset associated with it. Drivers using the CMA helpers should set this
* as their DRM driver's ->dumb_map_offset() callback.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv,
struct drm_device *drm, u32 handle,
u64 *offset)
{
struct drm_gem_object *gem_obj;
gem_obj = drm_gem_object_lookup(drm, file_priv, handle);
if (!gem_obj) {
dev_err(drm->dev, "failed to lookup GEM object\n");
return -EINVAL;
}
*offset = drm_vma_node_offset_addr(&gem_obj->vma_node);
drm_gem_object_unreference_unlocked(gem_obj);
return 0;
}
EXPORT_SYMBOL_GPL(drm_gem_cma_dumb_map_offset);
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_writecombine(cma_obj->base.dev->dev, vma,
cma_obj->vaddr, cma_obj->paddr,
vma->vm_end - vma->vm_start);
if (ret)
drm_gem_vm_close(vma);
return ret;
}
/**
* drm_gem_cma_mmap - memory-map a CMA GEM object
* @filp: file object
* @vma: VMA for the area to be mapped
*
* This function implements an augmented version of the GEM DRM file mmap
* operation for CMA objects: In addition to the usual GEM VMA setup it
* immediately faults in the entire object instead of using on-demaind
* faulting. Drivers which employ the CMA helpers should use this function
* as their ->mmap() handler in the DRM device file's file_operations
* structure.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct drm_gem_cma_object *cma_obj;
struct drm_gem_object *gem_obj;
int ret;
ret = drm_gem_mmap(filp, vma);
if (ret)
return ret;
gem_obj = vma->vm_private_data;
cma_obj = to_drm_gem_cma_obj(gem_obj);
return drm_gem_cma_mmap_obj(cma_obj, vma);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_mmap);
#ifdef CONFIG_DEBUG_FS
/**
* drm_gem_cma_describe - describe a CMA GEM object for debugfs
* @cma_obj: CMA GEM object
* @m: debugfs file handle
*
* This function can be used to dump a human-readable representation of the
* CMA GEM object into a synthetic file.
*/
void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj,
struct seq_file *m)
{
struct drm_gem_object *obj = &cma_obj->base;
uint64_t off;
off = drm_vma_node_start(&obj->vma_node);
seq_printf(m, "%2d (%2d) %08llx %pad %p %zu",
obj->name, obj->refcount.refcount.counter,
off, &cma_obj->paddr, cma_obj->vaddr, obj->size);
seq_printf(m, "\n");
}
EXPORT_SYMBOL_GPL(drm_gem_cma_describe);
#endif
/**
* drm_gem_cma_prime_get_sg_table - provide a scatter/gather table of pinned
* pages for a CMA GEM object
* @obj: GEM object
*
* This function exports a scatter/gather table suitable for PRIME usage by
* calling the standard DMA mapping API. Drivers using the CMA helpers should
* set this as their DRM driver's ->gem_prime_get_sg_table() callback.
*
* Returns:
* A pointer to the scatter/gather table of pinned pages or NULL on failure.
*/
struct sg_table *drm_gem_cma_prime_get_sg_table(struct drm_gem_object *obj)
{
struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
struct sg_table *sgt;
int ret;
sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
if (!sgt)
return NULL;
ret = dma_get_sgtable(obj->dev->dev, sgt, cma_obj->vaddr,
cma_obj->paddr, obj->size);
if (ret < 0)
goto out;
return sgt;
out:
kfree(sgt);
return NULL;
}
EXPORT_SYMBOL_GPL(drm_gem_cma_prime_get_sg_table);
/**
* drm_gem_cma_prime_import_sg_table - produce a CMA GEM object from another
* driver's scatter/gather table of pinned pages
* @dev: device to import into
* @attach: DMA-BUF attachment
* @sgt: scatter/gather table of pinned pages
*
* This function imports a scatter/gather table exported via DMA-BUF by
* another driver. Imported buffers must be physically contiguous in memory
* (i.e. the scatter/gather table must contain a single entry). Drivers that
* use the CMA helpers should set this as their DRM driver's
* ->gem_prime_import_sg_table() callback.
*
* Returns:
* A pointer to a newly created GEM object or an ERR_PTR-encoded negative
* error code on failure.
*/
struct drm_gem_object *
drm_gem_cma_prime_import_sg_table(struct drm_device *dev,
struct dma_buf_attachment *attach,
struct sg_table *sgt)
{
struct drm_gem_cma_object *cma_obj;
if (sgt->nents != 1)
return ERR_PTR(-EINVAL);
/* Create a CMA GEM buffer. */
cma_obj = __drm_gem_cma_create(dev, attach->dmabuf->size);
if (IS_ERR(cma_obj))
return ERR_CAST(cma_obj);
cma_obj->paddr = sg_dma_address(sgt->sgl);
cma_obj->sgt = sgt;
DRM_DEBUG_PRIME("dma_addr = %pad, size = %zu\n", &cma_obj->paddr, attach->dmabuf->size);
return &cma_obj->base;
}
EXPORT_SYMBOL_GPL(drm_gem_cma_prime_import_sg_table);
/**
* drm_gem_cma_prime_mmap - memory-map an exported CMA GEM object
* @obj: GEM object
* @vma: VMA for the area to be mapped
*
* This function maps a buffer imported via DRM PRIME into a userspace
* process's address space. Drivers that use the CMA helpers should set this
* as their DRM driver's ->gem_prime_mmap() callback.
*
* Returns:
* 0 on success or a negative error code on failure.
*/
int drm_gem_cma_prime_mmap(struct drm_gem_object *obj,
struct vm_area_struct *vma)
{
struct drm_gem_cma_object *cma_obj;
int ret;
ret = drm_gem_mmap_obj(obj, obj->size, vma);
if (ret < 0)
return ret;
cma_obj = to_drm_gem_cma_obj(obj);
return drm_gem_cma_mmap_obj(cma_obj, vma);
}
EXPORT_SYMBOL_GPL(drm_gem_cma_prime_mmap);
/**
* drm_gem_cma_prime_vmap - map a CMA GEM object into the kernel's virtual
* address space
* @obj: GEM object
*
* This function maps a buffer exported via DRM PRIME into the kernel's
* virtual address space. Since the CMA buffers are already mapped into the
* kernel virtual address space this simply returns the cached virtual
* address. Drivers using the CMA helpers should set this as their DRM
* driver's ->gem_prime_vmap() callback.
*
* Returns:
* The kernel virtual address of the CMA GEM object's backing store.
*/
void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj)
{
struct drm_gem_cma_object *cma_obj = to_drm_gem_cma_obj(obj);
return cma_obj->vaddr;
}
EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vmap);
/**
* drm_gem_cma_prime_vunmap - unmap a CMA GEM object from the kernel's virtual
* address space
* @obj: GEM object
* @vaddr: kernel virtual address where the CMA GEM object was mapped
*
* This function removes a buffer exported via DRM PRIME from the kernel's
* virtual address space. This is a no-op because CMA buffers cannot be
* unmapped from kernel space. Drivers using the CMA helpers should set this
* as their DRM driver's ->gem_prime_vunmap() callback.
*/
void drm_gem_cma_prime_vunmap(struct drm_gem_object *obj, void *vaddr)
{
/* Nothing to do */
}
EXPORT_SYMBOL_GPL(drm_gem_cma_prime_vunmap);
