drm/doc: Add GEM/CMA helpers to kerneldoc (d7883f87) · Commits · e / devices / android_kernel_oneplus_sm7250

Documentation/DocBook/drm.tmpl

+6 −0

Original line number	Diff line number	Diff line
		@@ -963,6 +963,12 @@ struct drm_gem_object * (gem_prime_import)(struct drm_device dev,
		!Edrivers/gpu/drm/drm_mm.c
		!Iinclude/drm/drm_mm.h
		</sect2>
		<sect2>
		<title>CMA Helper Functions Reference</title>
		!Pdrivers/gpu/drm/drm_gem_cma_helper.c cma helpers
		!Edrivers/gpu/drm/drm_gem_cma_helper.c
		!Iinclude/drm/drm_gem_cma_helper.h
		</sect2>
		</sect1>

		<!-- Internals: mode setting -->

drivers/gpu/drm/drm_gem_cma_helper.c

+180 −40

Original line number	Diff line number	Diff line
		@@ -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 @@ __drm_gem_cma_create(struct drm_device *drm, unsigned int size)
		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 @@ struct drm_gem_cma_object drm_gem_cma_create(struct drm_device drm,
		}
		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;
		@@ -145,9 +174,14 @@ static struct drm_gem_cma_object *drm_gem_cma_create_with_handle(
		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)
		{
		@@ -170,15 +204,23 @@ 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 - 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.
		*
		* 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)
		struct drm_device *drm,
		struct drm_mode_create_dumb *args)
		{
		struct drm_gem_cma_object *cma_obj;
		int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
		@@ -189,18 +231,30 @@ 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);

		/*
		* 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 +262,7 @@ 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 +305,20 @@ 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 +338,16 @@ 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 +366,18 @@ 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 +401,23 @@ struct sg_table drm_gem_cma_prime_get_sg_table(struct drm_gem_object obj)
		}
		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 +442,18 @@ 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 +472,20 @@ 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 +494,17 @@ 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 */

include/drm/drm_gem_cma_helper.h

+17 −8

Original line number	Diff line number	Diff line
		@@ -4,6 +4,13 @@
		#include <drm/drmP.h>
		#include <drm/drm_gem.h>

		/**
		* struct drm_gem_cma_object - GEM object backed by CMA memory allocations
		* @base: base GEM object
		* @paddr: physical address of the backing memory
		* @sgt: scatter/gather table for imported PRIME buffers
		* @vaddr: kernel virtual address of the backing memory
		*/
		struct drm_gem_cma_object {
		struct drm_gem_object base;
		dma_addr_t paddr;
		@@ -19,23 +26,25 @@ to_drm_gem_cma_obj(struct drm_gem_object *gem_obj)
		return container_of(gem_obj, struct drm_gem_cma_object, base);
		}

		/* free gem object. */
		/* free GEM object */
		void drm_gem_cma_free_object(struct drm_gem_object *gem_obj);

		/* create memory region for drm framebuffer. */
		/* create memory region for DRM framebuffer */
		int drm_gem_cma_dumb_create(struct drm_file *file_priv,
		struct drm_device drm, struct drm_mode_create_dumb args);
		struct drm_device *drm,
		struct drm_mode_create_dumb *args);

		/* map memory region for drm framebuffer to user space. */
		/* map memory region for DRM framebuffer to user space */
		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);

		/* set vm_flags and we can change the vm attribute to other one at here. */
		/* set vm_flags and we can change the VM attribute to other one at here */
		int drm_gem_cma_mmap(struct file filp, struct vm_area_struct vma);

		/* allocate physical memory. */
		/* allocate physical memory */
		struct drm_gem_cma_object drm_gem_cma_create(struct drm_device drm,
		unsigned int size);
		size_t size);

		extern const struct vm_operations_struct drm_gem_cma_vm_ops;