diff options
Diffstat (limited to 'drivers/gpu/drm/drm_gem_cma_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_cma_helper.c | 259 |
1 files changed, 215 insertions, 44 deletions
diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c index 0316310e2cc4..e419eedf751d 100644 --- a/drivers/gpu/drm/drm_gem_cma_helper.c +++ b/drivers/gpu/drm/drm_gem_cma_helper.c @@ -29,18 +29,31 @@ #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: The drm device - * @size: The GEM object size + * @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. + * This function creates and initializes a GEM CMA object of the given size, + * but doesn't allocate any memory to back the object. * - * Return a struct drm_gem_cma_object* on success or ERR_PTR values on failure. + * 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, unsigned int size) +__drm_gem_cma_create(struct drm_device *drm, size_t size) { struct drm_gem_cma_object *cma_obj; struct drm_gem_object *gem_obj; @@ -69,14 +82,21 @@ error: 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 ERR_PTR values - * on failure. + * 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, - unsigned int size) + size_t size) { struct drm_gem_cma_object *cma_obj; int ret; @@ -104,17 +124,26 @@ error: } EXPORT_SYMBOL_GPL(drm_gem_cma_create); -/* - * drm_gem_cma_create_with_handle - allocate an object with the given - * size and create a gem handle on it +/** + * 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 ERR_PTR values - * on failure. + * 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, unsigned int size, - unsigned int *handle) +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; @@ -145,16 +174,19 @@ err_handle_create: return ERR_PTR(ret); } -/* - * drm_gem_cma_free_object - (struct drm_driver)->gem_free_object callback - * function +/** + * 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; - drm_gem_free_mmap_offset(gem_obj); - cma_obj = to_drm_gem_cma_obj(gem_obj); if (cma_obj->vaddr) { @@ -170,18 +202,26 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj) } EXPORT_SYMBOL_GPL(drm_gem_cma_free_object); -/* - * drm_gem_cma_dumb_create - (struct drm_driver)->dumb_create callback - * function +/** + * 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. * - * This aligns the pitch and size arguments to the minimum required. wrap - * this into your own function if you need bigger alignment. + * 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 *dev, struct drm_mode_create_dumb *args) +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; - int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8); if (args->pitch < min_pitch) args->pitch = min_pitch; @@ -189,18 +229,63 @@ int drm_gem_cma_dumb_create(struct drm_file *file_priv, if (args->size < args->pitch * args->height) args->size = args->pitch * args->height; - cma_obj = drm_gem_cma_create_with_handle(file_priv, dev, - args->size, &args->handle); + 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 - (struct drm_driver)->dumb_map_offset callback - * function +/** + * 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, uint32_t handle, uint64_t *offset) + struct drm_device *drm, u32 handle, + u64 *offset) { struct drm_gem_object *gem_obj; @@ -208,7 +293,7 @@ int drm_gem_cma_dumb_map_offset(struct drm_file *file_priv, gem_obj = drm_gem_object_lookup(drm, file_priv, handle); if (!gem_obj) { - dev_err(drm->dev, "failed to lookup gem object\n"); + dev_err(drm->dev, "failed to lookup GEM object\n"); mutex_unlock(&drm->struct_mutex); return -EINVAL; } @@ -251,8 +336,20 @@ static int drm_gem_cma_mmap_obj(struct drm_gem_cma_object *cma_obj, return ret; } -/* - * drm_gem_cma_mmap - (struct file_operation)->mmap callback function +/** + * 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) { @@ -272,7 +369,16 @@ int drm_gem_cma_mmap(struct file *filp, struct vm_area_struct *vma) EXPORT_SYMBOL_GPL(drm_gem_cma_mmap); #ifdef CONFIG_DEBUG_FS -void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m) +/** + * 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; struct drm_device *dev = obj->dev; @@ -291,7 +397,18 @@ void drm_gem_cma_describe(struct drm_gem_cma_object *cma_obj, struct seq_file *m EXPORT_SYMBOL_GPL(drm_gem_cma_describe); #endif -/* low-level interface prime helpers */ +/** + * 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); @@ -315,6 +432,23 @@ out: } 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, @@ -339,6 +473,18 @@ drm_gem_cma_prime_import_sg_table(struct drm_device *dev, } 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) { @@ -357,6 +503,20 @@ int drm_gem_cma_prime_mmap(struct drm_gem_object *obj, } 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); @@ -365,6 +525,17 @@ void *drm_gem_cma_prime_vmap(struct drm_gem_object *obj) } 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 */ |
