summaryrefslogtreecommitdiff
path: root/include/drm/ttm/ttm_bo_api.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/drm/ttm/ttm_bo_api.h')
-rw-r--r--include/drm/ttm/ttm_bo_api.h732
1 files changed, 732 insertions, 0 deletions
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
new file mode 100644
index 00000000..974c8f80
--- /dev/null
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -0,0 +1,732 @@
+/**************************************************************************
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial portions
+ * of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
+ * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+ * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+ * USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ **************************************************************************/
+/*
+ * Authors: Thomas Hellstrom <thellstrom-at-vmware-dot-com>
+ */
+
+#ifndef _TTM_BO_API_H_
+#define _TTM_BO_API_H_
+
+#include "drm_hashtab.h"
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/wait.h>
+#include <linux/mutex.h>
+#include <linux/mm.h>
+#include <linux/rbtree.h>
+#include <linux/bitmap.h>
+
+struct ttm_bo_device;
+
+struct drm_mm_node;
+
+
+/**
+ * struct ttm_placement
+ *
+ * @fpfn: first valid page frame number to put the object
+ * @lpfn: last valid page frame number to put the object
+ * @num_placement: number of preferred placements
+ * @placement: preferred placements
+ * @num_busy_placement: number of preferred placements when need to evict buffer
+ * @busy_placement: preferred placements when need to evict buffer
+ *
+ * Structure indicating the placement you request for an object.
+ */
+struct ttm_placement {
+ unsigned fpfn;
+ unsigned lpfn;
+ unsigned num_placement;
+ const uint32_t *placement;
+ unsigned num_busy_placement;
+ const uint32_t *busy_placement;
+};
+
+/**
+ * struct ttm_bus_placement
+ *
+ * @addr: mapped virtual address
+ * @base: bus base address
+ * @is_iomem: is this io memory ?
+ * @size: size in byte
+ * @offset: offset from the base address
+ * @io_reserved_vm: The VM system has a refcount in @io_reserved_count
+ * @io_reserved_count: Refcounting the numbers of callers to ttm_mem_io_reserve
+ *
+ * Structure indicating the bus placement of an object.
+ */
+struct ttm_bus_placement {
+ void *addr;
+ unsigned long base;
+ unsigned long size;
+ unsigned long offset;
+ bool is_iomem;
+ bool io_reserved_vm;
+ uint64_t io_reserved_count;
+};
+
+
+/**
+ * struct ttm_mem_reg
+ *
+ * @mm_node: Memory manager node.
+ * @size: Requested size of memory region.
+ * @num_pages: Actual size of memory region in pages.
+ * @page_alignment: Page alignment.
+ * @placement: Placement flags.
+ * @bus: Placement on io bus accessible to the CPU
+ *
+ * Structure indicating the placement and space resources used by a
+ * buffer object.
+ */
+
+struct ttm_mem_reg {
+ void *mm_node;
+ unsigned long start;
+ unsigned long size;
+ unsigned long num_pages;
+ uint32_t page_alignment;
+ uint32_t mem_type;
+ uint32_t placement;
+ struct ttm_bus_placement bus;
+};
+
+/**
+ * enum ttm_bo_type
+ *
+ * @ttm_bo_type_device: These are 'normal' buffers that can
+ * be mmapped by user space. Each of these bos occupy a slot in the
+ * device address space, that can be used for normal vm operations.
+ *
+ * @ttm_bo_type_kernel: These buffers are like ttm_bo_type_device buffers,
+ * but they cannot be accessed from user-space. For kernel-only use.
+ */
+
+enum ttm_bo_type {
+ ttm_bo_type_device,
+ ttm_bo_type_kernel
+};
+
+struct ttm_tt;
+
+/**
+ * struct ttm_buffer_object
+ *
+ * @bdev: Pointer to the buffer object device structure.
+ * @buffer_start: The virtual user-space start address of ttm_bo_type_user
+ * buffers.
+ * @type: The bo type.
+ * @destroy: Destruction function. If NULL, kfree is used.
+ * @num_pages: Actual number of pages.
+ * @addr_space_offset: Address space offset.
+ * @acc_size: Accounted size for this object.
+ * @kref: Reference count of this buffer object. When this refcount reaches
+ * zero, the object is put on the delayed delete list.
+ * @list_kref: List reference count of this buffer object. This member is
+ * used to avoid destruction while the buffer object is still on a list.
+ * Lru lists may keep one refcount, the delayed delete list, and kref != 0
+ * keeps one refcount. When this refcount reaches zero,
+ * the object is destroyed.
+ * @event_queue: Queue for processes waiting on buffer object status change.
+ * @mem: structure describing current placement.
+ * @persistent_swap_storage: Usually the swap storage is deleted for buffers
+ * pinned in physical memory. If this behaviour is not desired, this member
+ * holds a pointer to a persistent shmem object.
+ * @ttm: TTM structure holding system pages.
+ * @evicted: Whether the object was evicted without user-space knowing.
+ * @cpu_writes: For synchronization. Number of cpu writers.
+ * @lru: List head for the lru list.
+ * @ddestroy: List head for the delayed destroy list.
+ * @swap: List head for swap LRU list.
+ * @val_seq: Sequence of the validation holding the @reserved lock.
+ * Used to avoid starvation when many processes compete to validate the
+ * buffer. This member is protected by the bo_device::lru_lock.
+ * @seq_valid: The value of @val_seq is valid. This value is protected by
+ * the bo_device::lru_lock.
+ * @reserved: Deadlock-free lock used for synchronization state transitions.
+ * @sync_obj_arg: Opaque argument to synchronization object function.
+ * @sync_obj: Pointer to a synchronization object.
+ * @priv_flags: Flags describing buffer object internal state.
+ * @vm_rb: Rb node for the vm rb tree.
+ * @vm_node: Address space manager node.
+ * @offset: The current GPU offset, which can have different meanings
+ * depending on the memory type. For SYSTEM type memory, it should be 0.
+ * @cur_placement: Hint of current placement.
+ *
+ * Base class for TTM buffer object, that deals with data placement and CPU
+ * mappings. GPU mappings are really up to the driver, but for simpler GPUs
+ * the driver can usually use the placement offset @offset directly as the
+ * GPU virtual address. For drivers implementing multiple
+ * GPU memory manager contexts, the driver should manage the address space
+ * in these contexts separately and use these objects to get the correct
+ * placement and caching for these GPU maps. This makes it possible to use
+ * these objects for even quite elaborate memory management schemes.
+ * The destroy member, the API visibility of this object makes it possible
+ * to derive driver specific types.
+ */
+
+struct ttm_buffer_object {
+ /**
+ * Members constant at init.
+ */
+
+ struct ttm_bo_global *glob;
+ struct ttm_bo_device *bdev;
+ unsigned long buffer_start;
+ enum ttm_bo_type type;
+ void (*destroy) (struct ttm_buffer_object *);
+ unsigned long num_pages;
+ uint64_t addr_space_offset;
+ size_t acc_size;
+
+ /**
+ * Members not needing protection.
+ */
+
+ struct kref kref;
+ struct kref list_kref;
+ wait_queue_head_t event_queue;
+
+ /**
+ * Members protected by the bo::reserved lock.
+ */
+
+ struct ttm_mem_reg mem;
+ struct file *persistent_swap_storage;
+ struct ttm_tt *ttm;
+ bool evicted;
+
+ /**
+ * Members protected by the bo::reserved lock only when written to.
+ */
+
+ atomic_t cpu_writers;
+
+ /**
+ * Members protected by the bdev::lru_lock.
+ */
+
+ struct list_head lru;
+ struct list_head ddestroy;
+ struct list_head swap;
+ struct list_head io_reserve_lru;
+ uint32_t val_seq;
+ bool seq_valid;
+
+ /**
+ * Members protected by the bdev::lru_lock
+ * only when written to.
+ */
+
+ atomic_t reserved;
+
+ /**
+ * Members protected by struct buffer_object_device::fence_lock
+ * In addition, setting sync_obj to anything else
+ * than NULL requires bo::reserved to be held. This allows for
+ * checking NULL while reserved but not holding the mentioned lock.
+ */
+
+ void *sync_obj_arg;
+ void *sync_obj;
+ unsigned long priv_flags;
+
+ /**
+ * Members protected by the bdev::vm_lock
+ */
+
+ struct rb_node vm_rb;
+ struct drm_mm_node *vm_node;
+
+
+ /**
+ * Special members that are protected by the reserve lock
+ * and the bo::lock when written to. Can be read with
+ * either of these locks held.
+ */
+
+ unsigned long offset;
+ uint32_t cur_placement;
+};
+
+/**
+ * struct ttm_bo_kmap_obj
+ *
+ * @virtual: The current kernel virtual address.
+ * @page: The page when kmap'ing a single page.
+ * @bo_kmap_type: Type of bo_kmap.
+ *
+ * Object describing a kernel mapping. Since a TTM bo may be located
+ * in various memory types with various caching policies, the
+ * mapping can either be an ioremap, a vmap, a kmap or part of a
+ * premapped region.
+ */
+
+#define TTM_BO_MAP_IOMEM_MASK 0x80
+struct ttm_bo_kmap_obj {
+ void *virtual;
+ struct page *page;
+ enum {
+ ttm_bo_map_iomap = 1 | TTM_BO_MAP_IOMEM_MASK,
+ ttm_bo_map_vmap = 2,
+ ttm_bo_map_kmap = 3,
+ ttm_bo_map_premapped = 4 | TTM_BO_MAP_IOMEM_MASK,
+ } bo_kmap_type;
+ struct ttm_buffer_object *bo;
+};
+
+/**
+ * ttm_bo_reference - reference a struct ttm_buffer_object
+ *
+ * @bo: The buffer object.
+ *
+ * Returns a refcounted pointer to a buffer object.
+ */
+
+static inline struct ttm_buffer_object *
+ttm_bo_reference(struct ttm_buffer_object *bo)
+{
+ kref_get(&bo->kref);
+ return bo;
+}
+
+/**
+ * ttm_bo_wait - wait for buffer idle.
+ *
+ * @bo: The buffer object.
+ * @interruptible: Use interruptible wait.
+ * @no_wait: Return immediately if buffer is busy.
+ *
+ * This function must be called with the bo::mutex held, and makes
+ * sure any previous rendering to the buffer is completed.
+ * Note: It might be necessary to block validations before the
+ * wait by reserving the buffer.
+ * Returns -EBUSY if no_wait is true and the buffer is busy.
+ * Returns -ERESTARTSYS if interrupted by a signal.
+ */
+extern int ttm_bo_wait(struct ttm_buffer_object *bo, bool lazy,
+ bool interruptible, bool no_wait);
+/**
+ * ttm_bo_validate
+ *
+ * @bo: The buffer object.
+ * @placement: Proposed placement for the buffer object.
+ * @interruptible: Sleep interruptible if sleeping.
+ * @no_wait_reserve: Return immediately if other buffers are busy.
+ * @no_wait_gpu: Return immediately if the GPU is busy.
+ *
+ * Changes placement and caching policy of the buffer object
+ * according proposed placement.
+ * Returns
+ * -EINVAL on invalid proposed placement.
+ * -ENOMEM on out-of-memory condition.
+ * -EBUSY if no_wait is true and buffer busy.
+ * -ERESTARTSYS if interrupted by a signal.
+ */
+extern int ttm_bo_validate(struct ttm_buffer_object *bo,
+ struct ttm_placement *placement,
+ bool interruptible, bool no_wait_reserve,
+ bool no_wait_gpu);
+
+/**
+ * ttm_bo_unref
+ *
+ * @bo: The buffer object.
+ *
+ * Unreference and clear a pointer to a buffer object.
+ */
+extern void ttm_bo_unref(struct ttm_buffer_object **bo);
+
+
+/**
+ * ttm_bo_list_ref_sub
+ *
+ * @bo: The buffer object.
+ * @count: The number of references with which to decrease @bo::list_kref;
+ * @never_free: The refcount should not reach zero with this operation.
+ *
+ * Release @count lru list references to this buffer object.
+ */
+extern void ttm_bo_list_ref_sub(struct ttm_buffer_object *bo, int count,
+ bool never_free);
+
+/**
+ * ttm_bo_add_to_lru
+ *
+ * @bo: The buffer object.
+ *
+ * Add this bo to the relevant mem type lru and, if it's backed by
+ * system pages (ttms) to the swap list.
+ * This function must be called with struct ttm_bo_global::lru_lock held, and
+ * is typically called immediately prior to unreserving a bo.
+ */
+extern void ttm_bo_add_to_lru(struct ttm_buffer_object *bo);
+
+/**
+ * ttm_bo_del_from_lru
+ *
+ * @bo: The buffer object.
+ *
+ * Remove this bo from all lru lists used to lookup and reserve an object.
+ * This function must be called with struct ttm_bo_global::lru_lock held,
+ * and is usually called just immediately after the bo has been reserved to
+ * avoid recursive reservation from lru lists.
+ */
+extern int ttm_bo_del_from_lru(struct ttm_buffer_object *bo);
+
+
+/**
+ * ttm_bo_lock_delayed_workqueue
+ *
+ * Prevent the delayed workqueue from running.
+ * Returns
+ * True if the workqueue was queued at the time
+ */
+extern int ttm_bo_lock_delayed_workqueue(struct ttm_bo_device *bdev);
+
+/**
+ * ttm_bo_unlock_delayed_workqueue
+ *
+ * Allows the delayed workqueue to run.
+ */
+extern void ttm_bo_unlock_delayed_workqueue(struct ttm_bo_device *bdev,
+ int resched);
+
+/**
+ * ttm_bo_synccpu_write_grab
+ *
+ * @bo: The buffer object:
+ * @no_wait: Return immediately if buffer is busy.
+ *
+ * Synchronizes a buffer object for CPU RW access. This means
+ * blocking command submission that affects the buffer and
+ * waiting for buffer idle. This lock is recursive.
+ * Returns
+ * -EBUSY if the buffer is busy and no_wait is true.
+ * -ERESTARTSYS if interrupted by a signal.
+ */
+extern int
+ttm_bo_synccpu_write_grab(struct ttm_buffer_object *bo, bool no_wait);
+
+/**
+ * ttm_bo_synccpu_write_release:
+ *
+ * @bo : The buffer object.
+ *
+ * Releases a synccpu lock.
+ */
+extern void ttm_bo_synccpu_write_release(struct ttm_buffer_object *bo);
+
+/**
+ * ttm_bo_acc_size
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @bo_size: size of the buffer object in byte.
+ * @struct_size: size of the structure holding buffer object datas
+ *
+ * Returns size to account for a buffer object
+ */
+size_t ttm_bo_acc_size(struct ttm_bo_device *bdev,
+ unsigned long bo_size,
+ unsigned struct_size);
+size_t ttm_bo_dma_acc_size(struct ttm_bo_device *bdev,
+ unsigned long bo_size,
+ unsigned struct_size);
+
+/**
+ * ttm_bo_init
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @size: Requested size of buffer object.
+ * @type: Requested type of buffer object.
+ * @flags: Initial placement flags.
+ * @page_alignment: Data alignment in pages.
+ * @buffer_start: Virtual address of user space data backing a
+ * user buffer object.
+ * @interruptible: If needing to sleep to wait for GPU resources,
+ * sleep interruptible.
+ * @persistent_swap_storage: Usually the swap storage is deleted for buffers
+ * pinned in physical memory. If this behaviour is not desired, this member
+ * holds a pointer to a persistent shmem object. Typically, this would
+ * point to the shmem object backing a GEM object if TTM is used to back a
+ * GEM user interface.
+ * @acc_size: Accounted size for this object.
+ * @destroy: Destroy function. Use NULL for kfree().
+ *
+ * This function initializes a pre-allocated struct ttm_buffer_object.
+ * As this object may be part of a larger structure, this function,
+ * together with the @destroy function,
+ * enables driver-specific objects derived from a ttm_buffer_object.
+ * On successful return, the object kref and list_kref are set to 1.
+ * If a failure occurs, the function will call the @destroy function, or
+ * kfree() if @destroy is NULL. Thus, after a failure, dereferencing @bo is
+ * illegal and will likely cause memory corruption.
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid placement flags.
+ * -ERESTARTSYS: Interrupted by signal while sleeping waiting for resources.
+ */
+
+extern int ttm_bo_init(struct ttm_bo_device *bdev,
+ struct ttm_buffer_object *bo,
+ unsigned long size,
+ enum ttm_bo_type type,
+ struct ttm_placement *placement,
+ uint32_t page_alignment,
+ unsigned long buffer_start,
+ bool interrubtible,
+ struct file *persistent_swap_storage,
+ size_t acc_size,
+ void (*destroy) (struct ttm_buffer_object *));
+
+/**
+ * ttm_bo_synccpu_object_init
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @bo: Pointer to a ttm_buffer_object to be initialized.
+ * @size: Requested size of buffer object.
+ * @type: Requested type of buffer object.
+ * @flags: Initial placement flags.
+ * @page_alignment: Data alignment in pages.
+ * @buffer_start: Virtual address of user space data backing a
+ * user buffer object.
+ * @interruptible: If needing to sleep while waiting for GPU resources,
+ * sleep interruptible.
+ * @persistent_swap_storage: Usually the swap storage is deleted for buffers
+ * pinned in physical memory. If this behaviour is not desired, this member
+ * holds a pointer to a persistent shmem object. Typically, this would
+ * point to the shmem object backing a GEM object if TTM is used to back a
+ * GEM user interface.
+ * @p_bo: On successful completion *p_bo points to the created object.
+ *
+ * This function allocates a ttm_buffer_object, and then calls ttm_bo_init
+ * on that object. The destroy function is set to kfree().
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid placement flags.
+ * -ERESTARTSYS: Interrupted by signal while waiting for resources.
+ */
+
+extern int ttm_bo_create(struct ttm_bo_device *bdev,
+ unsigned long size,
+ enum ttm_bo_type type,
+ struct ttm_placement *placement,
+ uint32_t page_alignment,
+ unsigned long buffer_start,
+ bool interruptible,
+ struct file *persistent_swap_storage,
+ struct ttm_buffer_object **p_bo);
+
+/**
+ * ttm_bo_check_placement
+ *
+ * @bo: the buffer object.
+ * @placement: placements
+ *
+ * Performs minimal validity checking on an intended change of
+ * placement flags.
+ * Returns
+ * -EINVAL: Intended change is invalid or not allowed.
+ */
+extern int ttm_bo_check_placement(struct ttm_buffer_object *bo,
+ struct ttm_placement *placement);
+
+/**
+ * ttm_bo_init_mm
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @mem_type: The memory type.
+ * @p_size: size managed area in pages.
+ *
+ * Initialize a manager for a given memory type.
+ * Note: if part of driver firstopen, it must be protected from a
+ * potentially racing lastclose.
+ * Returns:
+ * -EINVAL: invalid size or memory type.
+ * -ENOMEM: Not enough memory.
+ * May also return driver-specified errors.
+ */
+
+extern int ttm_bo_init_mm(struct ttm_bo_device *bdev, unsigned type,
+ unsigned long p_size);
+/**
+ * ttm_bo_clean_mm
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @mem_type: The memory type.
+ *
+ * Take down a manager for a given memory type after first walking
+ * the LRU list to evict any buffers left alive.
+ *
+ * Normally, this function is part of lastclose() or unload(), and at that
+ * point there shouldn't be any buffers left created by user-space, since
+ * there should've been removed by the file descriptor release() method.
+ * However, before this function is run, make sure to signal all sync objects,
+ * and verify that the delayed delete queue is empty. The driver must also
+ * make sure that there are no NO_EVICT buffers present in this memory type
+ * when the call is made.
+ *
+ * If this function is part of a VT switch, the caller must make sure that
+ * there are no appications currently validating buffers before this
+ * function is called. The caller can do that by first taking the
+ * struct ttm_bo_device::ttm_lock in write mode.
+ *
+ * Returns:
+ * -EINVAL: invalid or uninitialized memory type.
+ * -EBUSY: There are still buffers left in this memory type.
+ */
+
+extern int ttm_bo_clean_mm(struct ttm_bo_device *bdev, unsigned mem_type);
+
+/**
+ * ttm_bo_evict_mm
+ *
+ * @bdev: Pointer to a ttm_bo_device struct.
+ * @mem_type: The memory type.
+ *
+ * Evicts all buffers on the lru list of the memory type.
+ * This is normally part of a VT switch or an
+ * out-of-memory-space-due-to-fragmentation handler.
+ * The caller must make sure that there are no other processes
+ * currently validating buffers, and can do that by taking the
+ * struct ttm_bo_device::ttm_lock in write mode.
+ *
+ * Returns:
+ * -EINVAL: Invalid or uninitialized memory type.
+ * -ERESTARTSYS: The call was interrupted by a signal while waiting to
+ * evict a buffer.
+ */
+
+extern int ttm_bo_evict_mm(struct ttm_bo_device *bdev, unsigned mem_type);
+
+/**
+ * ttm_kmap_obj_virtual
+ *
+ * @map: A struct ttm_bo_kmap_obj returned from ttm_bo_kmap.
+ * @is_iomem: Pointer to an integer that on return indicates 1 if the
+ * virtual map is io memory, 0 if normal memory.
+ *
+ * Returns the virtual address of a buffer object area mapped by ttm_bo_kmap.
+ * If *is_iomem is 1 on return, the virtual address points to an io memory area,
+ * that should strictly be accessed by the iowriteXX() and similar functions.
+ */
+
+static inline void *ttm_kmap_obj_virtual(struct ttm_bo_kmap_obj *map,
+ bool *is_iomem)
+{
+ *is_iomem = !!(map->bo_kmap_type & TTM_BO_MAP_IOMEM_MASK);
+ return map->virtual;
+}
+
+/**
+ * ttm_bo_kmap
+ *
+ * @bo: The buffer object.
+ * @start_page: The first page to map.
+ * @num_pages: Number of pages to map.
+ * @map: pointer to a struct ttm_bo_kmap_obj representing the map.
+ *
+ * Sets up a kernel virtual mapping, using ioremap, vmap or kmap to the
+ * data in the buffer object. The ttm_kmap_obj_virtual function can then be
+ * used to obtain a virtual address to the data.
+ *
+ * Returns
+ * -ENOMEM: Out of memory.
+ * -EINVAL: Invalid range.
+ */
+
+extern int ttm_bo_kmap(struct ttm_buffer_object *bo, unsigned long start_page,
+ unsigned long num_pages, struct ttm_bo_kmap_obj *map);
+
+/**
+ * ttm_bo_kunmap
+ *
+ * @map: Object describing the map to unmap.
+ *
+ * Unmaps a kernel map set up by ttm_bo_kmap.
+ */
+
+extern void ttm_bo_kunmap(struct ttm_bo_kmap_obj *map);
+
+/**
+ * ttm_fbdev_mmap - mmap fbdev memory backed by a ttm buffer object.
+ *
+ * @vma: vma as input from the fbdev mmap method.
+ * @bo: The bo backing the address space. The address space will
+ * have the same size as the bo, and start at offset 0.
+ *
+ * This function is intended to be called by the fbdev mmap method
+ * if the fbdev address space is to be backed by a bo.
+ */
+
+extern int ttm_fbdev_mmap(struct vm_area_struct *vma,
+ struct ttm_buffer_object *bo);
+
+/**
+ * ttm_bo_mmap - mmap out of the ttm device address space.
+ *
+ * @filp: filp as input from the mmap method.
+ * @vma: vma as input from the mmap method.
+ * @bdev: Pointer to the ttm_bo_device with the address space manager.
+ *
+ * This function is intended to be called by the device mmap method.
+ * if the device address space is to be backed by the bo manager.
+ */
+
+extern int ttm_bo_mmap(struct file *filp, struct vm_area_struct *vma,
+ struct ttm_bo_device *bdev);
+
+/**
+ * ttm_bo_io
+ *
+ * @bdev: Pointer to the struct ttm_bo_device.
+ * @filp: Pointer to the struct file attempting to read / write.
+ * @wbuf: User-space pointer to address of buffer to write. NULL on read.
+ * @rbuf: User-space pointer to address of buffer to read into.
+ * Null on write.
+ * @count: Number of bytes to read / write.
+ * @f_pos: Pointer to current file position.
+ * @write: 1 for read, 0 for write.
+ *
+ * This function implements read / write into ttm buffer objects, and is
+ * intended to
+ * be called from the fops::read and fops::write method.
+ * Returns:
+ * See man (2) write, man(2) read. In particular,
+ * the function may return -ERESTARTSYS if
+ * interrupted by a signal.
+ */
+
+extern ssize_t ttm_bo_io(struct ttm_bo_device *bdev, struct file *filp,
+ const char __user *wbuf, char __user *rbuf,
+ size_t count, loff_t *f_pos, bool write);
+
+extern void ttm_bo_swapout_all(struct ttm_bo_device *bdev);
+
+#endif