OSCL-LXR linux-6.0.1/​drivers/​gpu/​drm/​drm_gem_vram_helper.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 
 #include <linux/iosys-map.h>
 #include <linux/module.h>
 
 #include <drm/drm_debugfs.h>
 #include <drm/drm_device.h>
 #include <drm/drm_drv.h>
 #include <drm/drm_file.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_atomic_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_gem_ttm_helper.h>
 #include <drm/drm_gem_vram_helper.h>
 #include <drm/drm_managed.h>
 #include <drm/drm_mode.h>
 #include <drm/drm_plane.h>
 #include <drm/drm_prime.h>
 #include <drm/drm_simple_kms_helper.h>
 
 #include <drm/ttm/ttm_range_manager.h>
 
 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs;
 
 /**
  * DOC: overview
  *
  * This library provides &struct drm_gem_vram_object (GEM VRAM), a GEM
  * buffer object that is backed by video RAM (VRAM). It can be used for
  * framebuffer devices with dedicated memory.
  *
  * The data structure &struct drm_vram_mm and its helpers implement a memory
  * manager for simple framebuffer devices with dedicated video memory. GEM
  * VRAM buffer objects are either placed in the video memory or remain evicted
  * to system memory.
  *
  * With the GEM interface userspace applications create, manage and destroy
  * graphics buffers, such as an on-screen framebuffer. GEM does not provide
  * an implementation of these interfaces. It's up to the DRM driver to
  * provide an implementation that suits the hardware. If the hardware device
  * contains dedicated video memory, the DRM driver can use the VRAM helper
  * library. Each active buffer object is stored in video RAM. Active
  * buffer are used for drawing the current frame, typically something like
  * the frame's scanout buffer or the cursor image. If there's no more space
  * left in VRAM, inactive GEM objects can be moved to system memory.
  *
  * To initialize the VRAM helper library call drmm_vram_helper_alloc_mm().
  * The function allocates and initializes an instance of &struct drm_vram_mm
  * in &struct drm_device.vram_mm . Use &DRM_GEM_VRAM_DRIVER to initialize
  * &struct drm_driver and  &DRM_VRAM_MM_FILE_OPERATIONS to initialize
  * &struct file_operations; as illustrated below.
  *
  * .. code-block:: c
  *
  *  struct file_operations fops ={
  *      .owner = THIS_MODULE,
  *      DRM_VRAM_MM_FILE_OPERATION
  *  };
  *  struct drm_driver drv = {
  *      .driver_feature = DRM_ ... ,
  *      .fops = &fops,
  *      DRM_GEM_VRAM_DRIVER
  *  };
  *
  *  int init_drm_driver()
  *  {
  *      struct drm_device *dev;
  *      uint64_t vram_base;
  *      unsigned long vram_size;
  *      int ret;
  *
  *      // setup device, vram base and size
  *      // ...
  *
  *      ret = drmm_vram_helper_alloc_mm(dev, vram_base, vram_size);
  *      if (ret)
  *          return ret;
  *      return 0;
  *  }
  *
  * This creates an instance of &struct drm_vram_mm, exports DRM userspace
  * interfaces for GEM buffer management and initializes file operations to
  * allow for accessing created GEM buffers. With this setup, the DRM driver
  * manages an area of video RAM with VRAM MM and provides GEM VRAM objects
  * to userspace.
  *
  * You don't have to clean up the instance of VRAM MM.
  * drmm_vram_helper_alloc_mm() is a managed interface that installs a
  * clean-up handler to run during the DRM device's release.
  *
  * For drawing or scanout operations, rsp. buffer objects have to be pinned
  * in video RAM. Call drm_gem_vram_pin() with &DRM_GEM_VRAM_PL_FLAG_VRAM or
  * &DRM_GEM_VRAM_PL_FLAG_SYSTEM to pin a buffer object in video RAM or system
  * memory. Call drm_gem_vram_unpin() to release the pinned object afterwards.
  *
  * A buffer object that is pinned in video RAM has a fixed address within that
  * memory region. Call drm_gem_vram_offset() to retrieve this value. Typically
  * it's used to program the hardware's scanout engine for framebuffers, set
  * the cursor overlay's image for a mouse cursor, or use it as input to the
  * hardware's drawing engine.
  *
  * To access a buffer object's memory from the DRM driver, call
  * drm_gem_vram_vmap(). It maps the buffer into kernel address
  * space and returns the memory address. Use drm_gem_vram_vunmap() to
  * release the mapping.
  */
 
 /*
  * Buffer-objects helpers
  */
 
 static void drm_gem_vram_cleanup(struct drm_gem_vram_object *gbo)
 {
     /* We got here via ttm_bo_put(), which means that the
      * TTM buffer object in 'bo' has already been cleaned
      * up; only release the GEM object.
      */
 
     WARN_ON(gbo->vmap_use_count);
     WARN_ON(iosys_map_is_set(&gbo->map));
 
     drm_gem_object_release(&gbo->bo.base);
 }
 
 static void drm_gem_vram_destroy(struct drm_gem_vram_object *gbo)
 {
     drm_gem_vram_cleanup(gbo);
     kfree(gbo);
 }
 
 static void ttm_buffer_object_destroy(struct ttm_buffer_object *bo)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_bo(bo);
 
     drm_gem_vram_destroy(gbo);
 }
 
 static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo,
                    unsigned long pl_flag)
 {
     u32 invariant_flags = 0;
     unsigned int i;
     unsigned int c = 0;
 
     if (pl_flag & DRM_GEM_VRAM_PL_FLAG_TOPDOWN)
         invariant_flags = TTM_PL_FLAG_TOPDOWN;
 
     gbo->placement.placement = gbo->placements;
     gbo->placement.busy_placement = gbo->placements;
 
     if (pl_flag & DRM_GEM_VRAM_PL_FLAG_VRAM) {
         gbo->placements[c].mem_type = TTM_PL_VRAM;
         gbo->placements[c++].flags = invariant_flags;
     }
 
     if (pl_flag & DRM_GEM_VRAM_PL_FLAG_SYSTEM || !c) {
         gbo->placements[c].mem_type = TTM_PL_SYSTEM;
         gbo->placements[c++].flags = invariant_flags;
     }
 
     gbo->placement.num_placement = c;
     gbo->placement.num_busy_placement = c;
 
     for (i = 0; i < c; ++i) {
         gbo->placements[i].fpfn = 0;
         gbo->placements[i].lpfn = 0;
     }
 }
 
 /**
  * drm_gem_vram_create() - Creates a VRAM-backed GEM object
  * @dev:        the DRM device
  * @size:       the buffer size in bytes
  * @pg_align:       the buffer's alignment in multiples of the page size
  *
  * GEM objects are allocated by calling struct drm_driver.gem_create_object,
  * if set. Otherwise kzalloc() will be used. Drivers can set their own GEM
  * object functions in struct drm_driver.gem_create_object. If no functions
  * are set, the new GEM object will use the default functions from GEM VRAM
  * helpers.
  *
  * Returns:
  * A new instance of &struct drm_gem_vram_object on success, or
  * an ERR_PTR()-encoded error code otherwise.
  */
 struct drm_gem_vram_object *drm_gem_vram_create(struct drm_device *dev,
                         size_t size,
                         unsigned long pg_align)
 {
     struct drm_gem_vram_object *gbo;
     struct drm_gem_object *gem;
     struct drm_vram_mm *vmm = dev->vram_mm;
     struct ttm_device *bdev;
     int ret;
 
     if (WARN_ONCE(!vmm, "VRAM MM not initialized"))
         return ERR_PTR(-EINVAL);
 
     if (dev->driver->gem_create_object) {
         gem = dev->driver->gem_create_object(dev, size);
         if (IS_ERR(gem))
             return ERR_CAST(gem);
         gbo = drm_gem_vram_of_gem(gem);
     } else {
         gbo = kzalloc(sizeof(*gbo), GFP_KERNEL);
         if (!gbo)
             return ERR_PTR(-ENOMEM);
         gem = &gbo->bo.base;
     }
 
     if (!gem->funcs)
         gem->funcs = &drm_gem_vram_object_funcs;
 
     ret = drm_gem_object_init(dev, gem, size);
     if (ret) {
         kfree(gbo);
         return ERR_PTR(ret);
     }
 
     bdev = &vmm->bdev;
 
     gbo->bo.bdev = bdev;
     drm_gem_vram_placement(gbo, DRM_GEM_VRAM_PL_FLAG_SYSTEM);
 
     /*
      * A failing ttm_bo_init will call ttm_buffer_object_destroy
      * to release gbo->bo.base and kfree gbo.
      */
     ret = ttm_bo_init(bdev, &gbo->bo, size, ttm_bo_type_device,
               &gbo->placement, pg_align, false, NULL, NULL,
               ttm_buffer_object_destroy);
     if (ret)
         return ERR_PTR(ret);
 
     return gbo;
 }
 EXPORT_SYMBOL(drm_gem_vram_create);
 
 /**
  * drm_gem_vram_put() - Releases a reference to a VRAM-backed GEM object
  * @gbo:    the GEM VRAM object
  *
  * See ttm_bo_put() for more information.
  */
 void drm_gem_vram_put(struct drm_gem_vram_object *gbo)
 {
     ttm_bo_put(&gbo->bo);
 }
 EXPORT_SYMBOL(drm_gem_vram_put);
 
 static u64 drm_gem_vram_pg_offset(struct drm_gem_vram_object *gbo)
 {
     /* Keep TTM behavior for now, remove when drivers are audited */
     if (WARN_ON_ONCE(!gbo->bo.resource ||
              gbo->bo.resource->mem_type == TTM_PL_SYSTEM))
         return 0;
 
     return gbo->bo.resource->start;
 }
 
 /**
  * drm_gem_vram_offset() - \
     Returns a GEM VRAM object's offset in video memory
  * @gbo:    the GEM VRAM object
  *
  * This function returns the buffer object's offset in the device's video
  * memory. The buffer object has to be pinned to %TTM_PL_VRAM.
  *
  * Returns:
  * The buffer object's offset in video memory on success, or
  * a negative errno code otherwise.
  */
 s64 drm_gem_vram_offset(struct drm_gem_vram_object *gbo)
 {
     if (WARN_ON_ONCE(!gbo->bo.pin_count))
         return (s64)-ENODEV;
     return drm_gem_vram_pg_offset(gbo) << PAGE_SHIFT;
 }
 EXPORT_SYMBOL(drm_gem_vram_offset);
 
 static int drm_gem_vram_pin_locked(struct drm_gem_vram_object *gbo,
                    unsigned long pl_flag)
 {
     struct ttm_operation_ctx ctx = { false, false };
     int ret;
 
     if (gbo->bo.pin_count)
         goto out;
 
     if (pl_flag)
         drm_gem_vram_placement(gbo, pl_flag);
 
     ret = ttm_bo_validate(&gbo->bo, &gbo->placement, &ctx);
     if (ret < 0)
         return ret;
 
 out:
     ttm_bo_pin(&gbo->bo);
 
     return 0;
 }
 
 /**
  * drm_gem_vram_pin() - Pins a GEM VRAM object in a region.
  * @gbo:    the GEM VRAM object
  * @pl_flag:    a bitmask of possible memory regions
  *
  * Pinning a buffer object ensures that it is not evicted from
  * a memory region. A pinned buffer object has to be unpinned before
  * it can be pinned to another region. If the pl_flag argument is 0,
  * the buffer is pinned at its current location (video RAM or system
  * memory).
  *
  * Small buffer objects, such as cursor images, can lead to memory
  * fragmentation if they are pinned in the middle of video RAM. This
  * is especially a problem on devices with only a small amount of
  * video RAM. Fragmentation can prevent the primary framebuffer from
  * fitting in, even though there's enough memory overall. The modifier
  * DRM_GEM_VRAM_PL_FLAG_TOPDOWN marks the buffer object to be pinned
  * at the high end of the memory region to avoid fragmentation.
  *
  * Returns:
  * 0 on success, or
  * a negative error code otherwise.
  */
 int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag)
 {
     int ret;
 
     ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
     if (ret)
         return ret;
     ret = drm_gem_vram_pin_locked(gbo, pl_flag);
     ttm_bo_unreserve(&gbo->bo);
 
     return ret;
 }
 EXPORT_SYMBOL(drm_gem_vram_pin);
 
 static void drm_gem_vram_unpin_locked(struct drm_gem_vram_object *gbo)
 {
     ttm_bo_unpin(&gbo->bo);
 }
 
 /**
  * drm_gem_vram_unpin() - Unpins a GEM VRAM object
  * @gbo:    the GEM VRAM object
  *
  * Returns:
  * 0 on success, or
  * a negative error code otherwise.
  */
 int drm_gem_vram_unpin(struct drm_gem_vram_object *gbo)
 {
     int ret;
 
     ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
     if (ret)
         return ret;
 
     drm_gem_vram_unpin_locked(gbo);
     ttm_bo_unreserve(&gbo->bo);
 
     return 0;
 }
 EXPORT_SYMBOL(drm_gem_vram_unpin);
 
 static int drm_gem_vram_kmap_locked(struct drm_gem_vram_object *gbo,
                     struct iosys_map *map)
 {
     int ret;
 
     if (gbo->vmap_use_count > 0)
         goto out;
 
     /*
      * VRAM helpers unmap the BO only on demand. So the previous
      * page mapping might still be around. Only vmap if the there's
      * no mapping present.
      */
     if (iosys_map_is_null(&gbo->map)) {
         ret = ttm_bo_vmap(&gbo->bo, &gbo->map);
         if (ret)
             return ret;
     }
 
 out:
     ++gbo->vmap_use_count;
     *map = gbo->map;
 
     return 0;
 }
 
 static void drm_gem_vram_kunmap_locked(struct drm_gem_vram_object *gbo,
                        struct iosys_map *map)
 {
     struct drm_device *dev = gbo->bo.base.dev;
 
     if (drm_WARN_ON_ONCE(dev, !gbo->vmap_use_count))
         return;
 
     if (drm_WARN_ON_ONCE(dev, !iosys_map_is_equal(&gbo->map, map)))
         return; /* BUG: map not mapped from this BO */
 
     if (--gbo->vmap_use_count > 0)
         return;
 
     /*
      * Permanently mapping and unmapping buffers adds overhead from
      * updating the page tables and creates debugging output. Therefore,
      * we delay the actual unmap operation until the BO gets evicted
      * from memory. See drm_gem_vram_bo_driver_move_notify().
      */
 }
 
 /**
  * drm_gem_vram_vmap() - Pins and maps a GEM VRAM object into kernel address
  *                       space
  * @gbo: The GEM VRAM object to map
  * @map: Returns the kernel virtual address of the VRAM GEM object's backing
  *       store.
  *
  * The vmap function pins a GEM VRAM object to its current location, either
  * system or video memory, and maps its buffer into kernel address space.
  * As pinned object cannot be relocated, you should avoid pinning objects
  * permanently. Call drm_gem_vram_vunmap() with the returned address to
  * unmap and unpin the GEM VRAM object.
  *
  * Returns:
  * 0 on success, or a negative error code otherwise.
  */
 int drm_gem_vram_vmap(struct drm_gem_vram_object *gbo, struct iosys_map *map)
 {
     int ret;
 
     ret = ttm_bo_reserve(&gbo->bo, true, false, NULL);
     if (ret)
         return ret;
 
     ret = drm_gem_vram_pin_locked(gbo, 0);
     if (ret)
         goto err_ttm_bo_unreserve;
     ret = drm_gem_vram_kmap_locked(gbo, map);
     if (ret)
         goto err_drm_gem_vram_unpin_locked;
 
     ttm_bo_unreserve(&gbo->bo);
 
     return 0;
 
 err_drm_gem_vram_unpin_locked:
     drm_gem_vram_unpin_locked(gbo);
 err_ttm_bo_unreserve:
     ttm_bo_unreserve(&gbo->bo);
     return ret;
 }
 EXPORT_SYMBOL(drm_gem_vram_vmap);
 
 /**
  * drm_gem_vram_vunmap() - Unmaps and unpins a GEM VRAM object
  * @gbo: The GEM VRAM object to unmap
  * @map: Kernel virtual address where the VRAM GEM object was mapped
  *
  * A call to drm_gem_vram_vunmap() unmaps and unpins a GEM VRAM buffer. See
  * the documentation for drm_gem_vram_vmap() for more information.
  */
 void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo,
              struct iosys_map *map)
 {
     int ret;
 
     ret = ttm_bo_reserve(&gbo->bo, false, false, NULL);
     if (WARN_ONCE(ret, "ttm_bo_reserve_failed(): ret=%d\n", ret))
         return;
 
     drm_gem_vram_kunmap_locked(gbo, map);
     drm_gem_vram_unpin_locked(gbo);
 
     ttm_bo_unreserve(&gbo->bo);
 }
 EXPORT_SYMBOL(drm_gem_vram_vunmap);
 
 /**
  * drm_gem_vram_fill_create_dumb() - \
     Helper for implementing &struct drm_driver.dumb_create
  * @file:       the DRM file
  * @dev:        the DRM device
  * @pg_align:       the buffer's alignment in multiples of the page size
  * @pitch_align:    the scanline's alignment in powers of 2
  * @args:       the arguments as provided to \
                 &struct drm_driver.dumb_create
  *
  * This helper function fills &struct drm_mode_create_dumb, which is used
  * by &struct drm_driver.dumb_create. Implementations of this interface
  * should forwards their arguments to this helper, plus the driver-specific
  * parameters.
  *
  * Returns:
  * 0 on success, or
  * a negative error code otherwise.
  */
 int drm_gem_vram_fill_create_dumb(struct drm_file *file,
                   struct drm_device *dev,
                   unsigned long pg_align,
                   unsigned long pitch_align,
                   struct drm_mode_create_dumb *args)
 {
     size_t pitch, size;
     struct drm_gem_vram_object *gbo;
     int ret;
     u32 handle;
 
     pitch = args->width * DIV_ROUND_UP(args->bpp, 8);
     if (pitch_align) {
         if (WARN_ON_ONCE(!is_power_of_2(pitch_align)))
             return -EINVAL;
         pitch = ALIGN(pitch, pitch_align);
     }
     size = pitch * args->height;
 
     size = roundup(size, PAGE_SIZE);
     if (!size)
         return -EINVAL;
 
     gbo = drm_gem_vram_create(dev, size, pg_align);
     if (IS_ERR(gbo))
         return PTR_ERR(gbo);
 
     ret = drm_gem_handle_create(file, &gbo->bo.base, &handle);
     if (ret)
         goto err_drm_gem_object_put;
 
     drm_gem_object_put(&gbo->bo.base);
 
     args->pitch = pitch;
     args->size = size;
     args->handle = handle;
 
     return 0;
 
 err_drm_gem_object_put:
     drm_gem_object_put(&gbo->bo.base);
     return ret;
 }
 EXPORT_SYMBOL(drm_gem_vram_fill_create_dumb);
 
 /*
  * Helpers for struct ttm_device_funcs
  */
 
 static bool drm_is_gem_vram(struct ttm_buffer_object *bo)
 {
     return (bo->destroy == ttm_buffer_object_destroy);
 }
 
 static void drm_gem_vram_bo_driver_evict_flags(struct drm_gem_vram_object *gbo,
                            struct ttm_placement *pl)
 {
     drm_gem_vram_placement(gbo, DRM_GEM_VRAM_PL_FLAG_SYSTEM);
     *pl = gbo->placement;
 }
 
 static void drm_gem_vram_bo_driver_move_notify(struct drm_gem_vram_object *gbo)
 {
     struct ttm_buffer_object *bo = &gbo->bo;
     struct drm_device *dev = bo->base.dev;
 
     if (drm_WARN_ON_ONCE(dev, gbo->vmap_use_count))
         return;
 
     ttm_bo_vunmap(bo, &gbo->map);
     iosys_map_clear(&gbo->map); /* explicitly clear mapping for next vmap call */
 }
 
 static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo,
                        bool evict,
                        struct ttm_operation_ctx *ctx,
                        struct ttm_resource *new_mem)
 {
     drm_gem_vram_bo_driver_move_notify(gbo);
     return ttm_bo_move_memcpy(&gbo->bo, ctx, new_mem);
 }
 
 /*
  * Helpers for struct drm_gem_object_funcs
  */
 
 /**
  * drm_gem_vram_object_free() - \
     Implements &struct drm_gem_object_funcs.free
  * @gem:       GEM object. Refers to &struct drm_gem_vram_object.gem
  */
 static void drm_gem_vram_object_free(struct drm_gem_object *gem)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 
     drm_gem_vram_put(gbo);
 }
 
 /*
  * Helpers for dump buffers
  */
 
 /**
  * drm_gem_vram_driver_dumb_create() - \
     Implements &struct drm_driver.dumb_create
  * @file:       the DRM file
  * @dev:        the DRM device
  * @args:       the arguments as provided to \
                 &struct drm_driver.dumb_create
  *
  * This function requires the driver to use @drm_device.vram_mm for its
  * instance of VRAM MM.
  *
  * Returns:
  * 0 on success, or
  * a negative error code otherwise.
  */
 int drm_gem_vram_driver_dumb_create(struct drm_file *file,
                     struct drm_device *dev,
                     struct drm_mode_create_dumb *args)
 {
     if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
         return -EINVAL;
 
     return drm_gem_vram_fill_create_dumb(file, dev, 0, 0, args);
 }
 EXPORT_SYMBOL(drm_gem_vram_driver_dumb_create);
 
 /*
  * Helpers for struct drm_plane_helper_funcs
  */
 
 static void __drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
                            struct drm_plane_state *state,
                            unsigned int num_planes)
 {
     struct drm_gem_object *obj;
     struct drm_gem_vram_object *gbo;
     struct drm_framebuffer *fb = state->fb;
 
     while (num_planes) {
         --num_planes;
         obj = drm_gem_fb_get_obj(fb, num_planes);
         if (!obj)
             continue;
         gbo = drm_gem_vram_of_gem(obj);
         drm_gem_vram_unpin(gbo);
     }
 }
 
 /**
  * drm_gem_vram_plane_helper_prepare_fb() - \
  *  Implements &struct drm_plane_helper_funcs.prepare_fb
  * @plane:  a DRM plane
  * @new_state:  the plane's new state
  *
  * During plane updates, this function sets the plane's fence and
  * pins the GEM VRAM objects of the plane's new framebuffer to VRAM.
  * Call drm_gem_vram_plane_helper_cleanup_fb() to unpin them.
  *
  * Returns:
  *  0 on success, or
  *  a negative errno code otherwise.
  */
 int
 drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane,
                      struct drm_plane_state *new_state)
 {
     struct drm_framebuffer *fb = new_state->fb;
     struct drm_gem_vram_object *gbo;
     struct drm_gem_object *obj;
     unsigned int i;
     int ret;
 
     if (!fb)
         return 0;
 
     for (i = 0; i < fb->format->num_planes; ++i) {
         obj = drm_gem_fb_get_obj(fb, i);
         if (!obj) {
             ret = -EINVAL;
             goto err_drm_gem_vram_unpin;
         }
         gbo = drm_gem_vram_of_gem(obj);
         ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);
         if (ret)
             goto err_drm_gem_vram_unpin;
     }
 
     ret = drm_gem_plane_helper_prepare_fb(plane, new_state);
     if (ret)
         goto err_drm_gem_vram_unpin;
 
     return 0;
 
 err_drm_gem_vram_unpin:
     __drm_gem_vram_plane_helper_cleanup_fb(plane, new_state, i);
     return ret;
 }
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_prepare_fb);
 
 /**
  * drm_gem_vram_plane_helper_cleanup_fb() - \
  *  Implements &struct drm_plane_helper_funcs.cleanup_fb
  * @plane:  a DRM plane
  * @old_state:  the plane's old state
  *
  * During plane updates, this function unpins the GEM VRAM
  * objects of the plane's old framebuffer from VRAM. Complements
  * drm_gem_vram_plane_helper_prepare_fb().
  */
 void
 drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
                      struct drm_plane_state *old_state)
 {
     struct drm_framebuffer *fb = old_state->fb;
 
     if (!fb)
         return;
 
     __drm_gem_vram_plane_helper_cleanup_fb(plane, old_state, fb->format->num_planes);
 }
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_cleanup_fb);
 
 /*
  * Helpers for struct drm_simple_display_pipe_funcs
  */
 
 /**
  * drm_gem_vram_simple_display_pipe_prepare_fb() - \
  *  Implements &struct drm_simple_display_pipe_funcs.prepare_fb
  * @pipe:   a simple display pipe
  * @new_state:  the plane's new state
  *
  * During plane updates, this function pins the GEM VRAM
  * objects of the plane's new framebuffer to VRAM. Call
  * drm_gem_vram_simple_display_pipe_cleanup_fb() to unpin them.
  *
  * Returns:
  *  0 on success, or
  *  a negative errno code otherwise.
  */
 int drm_gem_vram_simple_display_pipe_prepare_fb(
     struct drm_simple_display_pipe *pipe,
     struct drm_plane_state *new_state)
 {
     return drm_gem_vram_plane_helper_prepare_fb(&pipe->plane, new_state);
 }
 EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_prepare_fb);
 
 /**
  * drm_gem_vram_simple_display_pipe_cleanup_fb() - \
  *  Implements &struct drm_simple_display_pipe_funcs.cleanup_fb
  * @pipe:   a simple display pipe
  * @old_state:  the plane's old state
  *
  * During plane updates, this function unpins the GEM VRAM
  * objects of the plane's old framebuffer from VRAM. Complements
  * drm_gem_vram_simple_display_pipe_prepare_fb().
  */
 void drm_gem_vram_simple_display_pipe_cleanup_fb(
     struct drm_simple_display_pipe *pipe,
     struct drm_plane_state *old_state)
 {
     drm_gem_vram_plane_helper_cleanup_fb(&pipe->plane, old_state);
 }
 EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_cleanup_fb);
 
 /*
  * PRIME helpers
  */
 
 /**
  * drm_gem_vram_object_pin() - \
     Implements &struct drm_gem_object_funcs.pin
  * @gem:    The GEM object to pin
  *
  * Returns:
  * 0 on success, or
  * a negative errno code otherwise.
  */
 static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 
     /* Fbdev console emulation is the use case of these PRIME
      * helpers. This may involve updating a hardware buffer from
      * a shadow FB. We pin the buffer to it's current location
      * (either video RAM or system memory) to prevent it from
      * being relocated during the update operation. If you require
      * the buffer to be pinned to VRAM, implement a callback that
      * sets the flags accordingly.
      */
     return drm_gem_vram_pin(gbo, 0);
 }
 
 /**
  * drm_gem_vram_object_unpin() - \
     Implements &struct drm_gem_object_funcs.unpin
  * @gem:    The GEM object to unpin
  */
 static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 
     drm_gem_vram_unpin(gbo);
 }
 
 /**
  * drm_gem_vram_object_vmap() -
  *  Implements &struct drm_gem_object_funcs.vmap
  * @gem: The GEM object to map
  * @map: Returns the kernel virtual address of the VRAM GEM object's backing
  *       store.
  *
  * Returns:
  * 0 on success, or a negative error code otherwise.
  */
 static int drm_gem_vram_object_vmap(struct drm_gem_object *gem,
                     struct iosys_map *map)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 
     return drm_gem_vram_vmap(gbo, map);
 }
 
 /**
  * drm_gem_vram_object_vunmap() -
  *  Implements &struct drm_gem_object_funcs.vunmap
  * @gem: The GEM object to unmap
  * @map: Kernel virtual address where the VRAM GEM object was mapped
  */
 static void drm_gem_vram_object_vunmap(struct drm_gem_object *gem,
                        struct iosys_map *map)
 {
     struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);
 
     drm_gem_vram_vunmap(gbo, map);
 }
 
 /*
  * GEM object funcs
  */
 
 static const struct drm_gem_object_funcs drm_gem_vram_object_funcs = {
     .free   = drm_gem_vram_object_free,
     .pin    = drm_gem_vram_object_pin,
     .unpin  = drm_gem_vram_object_unpin,
     .vmap   = drm_gem_vram_object_vmap,
     .vunmap = drm_gem_vram_object_vunmap,
     .mmap   = drm_gem_ttm_mmap,
     .print_info = drm_gem_ttm_print_info,
 };
 
 /*
  * VRAM memory manager
  */
 
 /*
  * TTM TT
  */
 
 static void bo_driver_ttm_tt_destroy(struct ttm_device *bdev, struct ttm_tt *tt)
 {
     ttm_tt_fini(tt);
     kfree(tt);
 }
 
 /*
  * TTM BO device
  */
 
 static struct ttm_tt *bo_driver_ttm_tt_create(struct ttm_buffer_object *bo,
                           uint32_t page_flags)
 {
     struct ttm_tt *tt;
     int ret;
 
     tt = kzalloc(sizeof(*tt), GFP_KERNEL);
     if (!tt)
         return NULL;
 
     ret = ttm_tt_init(tt, bo, page_flags, ttm_cached, 0);
     if (ret < 0)
         goto err_ttm_tt_init;
 
     return tt;
 
 err_ttm_tt_init:
     kfree(tt);
     return NULL;
 }
 
 static void bo_driver_evict_flags(struct ttm_buffer_object *bo,
                   struct ttm_placement *placement)
 {
     struct drm_gem_vram_object *gbo;
 
     /* TTM may pass BOs that are not GEM VRAM BOs. */
     if (!drm_is_gem_vram(bo))
         return;
 
     gbo = drm_gem_vram_of_bo(bo);
 
     drm_gem_vram_bo_driver_evict_flags(gbo, placement);
 }
 
 static void bo_driver_delete_mem_notify(struct ttm_buffer_object *bo)
 {
     struct drm_gem_vram_object *gbo;
 
     /* TTM may pass BOs that are not GEM VRAM BOs. */
     if (!drm_is_gem_vram(bo))
         return;
 
     gbo = drm_gem_vram_of_bo(bo);
 
     drm_gem_vram_bo_driver_move_notify(gbo);
 }
 
 static int bo_driver_move(struct ttm_buffer_object *bo,
               bool evict,
               struct ttm_operation_ctx *ctx,
               struct ttm_resource *new_mem,
               struct ttm_place *hop)
 {
     struct drm_gem_vram_object *gbo;
 
     gbo = drm_gem_vram_of_bo(bo);
 
     return drm_gem_vram_bo_driver_move(gbo, evict, ctx, new_mem);
 }
 
 static int bo_driver_io_mem_reserve(struct ttm_device *bdev,
                     struct ttm_resource *mem)
 {
     struct drm_vram_mm *vmm = drm_vram_mm_of_bdev(bdev);
 
     switch (mem->mem_type) {
     case TTM_PL_SYSTEM: /* nothing to do */
         break;
     case TTM_PL_VRAM:
         mem->bus.offset = (mem->start << PAGE_SHIFT) + vmm->vram_base;
         mem->bus.is_iomem = true;
         mem->bus.caching = ttm_write_combined;
         break;
     default:
         return -EINVAL;
     }
 
     return 0;
 }
 
 static struct ttm_device_funcs bo_driver = {
     .ttm_tt_create = bo_driver_ttm_tt_create,
     .ttm_tt_destroy = bo_driver_ttm_tt_destroy,
     .eviction_valuable = ttm_bo_eviction_valuable,
     .evict_flags = bo_driver_evict_flags,
     .move = bo_driver_move,
     .delete_mem_notify = bo_driver_delete_mem_notify,
     .io_mem_reserve = bo_driver_io_mem_reserve,
 };
 
 /*
  * struct drm_vram_mm
  */
 
 static int drm_vram_mm_debugfs(struct seq_file *m, void *data)
 {
     struct drm_info_node *node = (struct drm_info_node *) m->private;
     struct drm_vram_mm *vmm = node->minor->dev->vram_mm;
     struct ttm_resource_manager *man = ttm_manager_type(&vmm->bdev, TTM_PL_VRAM);
     struct drm_printer p = drm_seq_file_printer(m);
 
     ttm_resource_manager_debug(man, &p);
     return 0;
 }
 
 static const struct drm_info_list drm_vram_mm_debugfs_list[] = {
     { "vram-mm", drm_vram_mm_debugfs, 0, NULL },
 };
 
 /**
  * drm_vram_mm_debugfs_init() - Register VRAM MM debugfs file.
  *
  * @minor: drm minor device.
  *
  */
 void drm_vram_mm_debugfs_init(struct drm_minor *minor)
 {
     drm_debugfs_create_files(drm_vram_mm_debugfs_list,
                  ARRAY_SIZE(drm_vram_mm_debugfs_list),
                  minor->debugfs_root, minor);
 }
 EXPORT_SYMBOL(drm_vram_mm_debugfs_init);
 
 static int drm_vram_mm_init(struct drm_vram_mm *vmm, struct drm_device *dev,
                 uint64_t vram_base, size_t vram_size)
 {
     int ret;
 
     vmm->vram_base = vram_base;
     vmm->vram_size = vram_size;
 
     ret = ttm_device_init(&vmm->bdev, &bo_driver, dev->dev,
                  dev->anon_inode->i_mapping,
                  dev->vma_offset_manager,
                  false, true);
     if (ret)
         return ret;
 
     ret = ttm_range_man_init(&vmm->bdev, TTM_PL_VRAM,
                  false, vram_size >> PAGE_SHIFT);
     if (ret)
         return ret;
 
     return 0;
 }
 
 static void drm_vram_mm_cleanup(struct drm_vram_mm *vmm)
 {
     ttm_range_man_fini(&vmm->bdev, TTM_PL_VRAM);
     ttm_device_fini(&vmm->bdev);
 }
 
 /*
  * Helpers for integration with struct drm_device
  */
 
 static struct drm_vram_mm *drm_vram_helper_alloc_mm(struct drm_device *dev, uint64_t vram_base,
                             size_t vram_size)
 {
     int ret;
 
     if (WARN_ON(dev->vram_mm))
         return dev->vram_mm;
 
     dev->vram_mm = kzalloc(sizeof(*dev->vram_mm), GFP_KERNEL);
     if (!dev->vram_mm)
         return ERR_PTR(-ENOMEM);
 
     ret = drm_vram_mm_init(dev->vram_mm, dev, vram_base, vram_size);
     if (ret)
         goto err_kfree;
 
     return dev->vram_mm;
 
 err_kfree:
     kfree(dev->vram_mm);
     dev->vram_mm = NULL;
     return ERR_PTR(ret);
 }
 
 static void drm_vram_helper_release_mm(struct drm_device *dev)
 {
     if (!dev->vram_mm)
         return;
 
     drm_vram_mm_cleanup(dev->vram_mm);
     kfree(dev->vram_mm);
     dev->vram_mm = NULL;
 }
 
 static void drm_vram_mm_release(struct drm_device *dev, void *ptr)
 {
     drm_vram_helper_release_mm(dev);
 }
 
 /**
  * drmm_vram_helper_init - Initializes a device's instance of
  *                         &struct drm_vram_mm
  * @dev:    the DRM device
  * @vram_base:  the base address of the video memory
  * @vram_size:  the size of the video memory in bytes
  *
  * Creates a new instance of &struct drm_vram_mm and stores it in
  * struct &drm_device.vram_mm. The instance is auto-managed and cleaned
  * up as part of device cleanup. Calling this function multiple times
  * will generate an error message.
  *
  * Returns:
  * 0 on success, or a negative errno code otherwise.
  */
 int drmm_vram_helper_init(struct drm_device *dev, uint64_t vram_base,
               size_t vram_size)
 {
     struct drm_vram_mm *vram_mm;
 
     if (drm_WARN_ON_ONCE(dev, dev->vram_mm))
         return 0;
 
     vram_mm = drm_vram_helper_alloc_mm(dev, vram_base, vram_size);
     if (IS_ERR(vram_mm))
         return PTR_ERR(vram_mm);
     return drmm_add_action_or_reset(dev, drm_vram_mm_release, NULL);
 }
 EXPORT_SYMBOL(drmm_vram_helper_init);
 
 /*
  * Mode-config helpers
  */
 
 static enum drm_mode_status
 drm_vram_helper_mode_valid_internal(struct drm_device *dev,
                     const struct drm_display_mode *mode,
                     unsigned long max_bpp)
 {
     struct drm_vram_mm *vmm = dev->vram_mm;
     unsigned long fbsize, fbpages, max_fbpages;
 
     if (WARN_ON(!dev->vram_mm))
         return MODE_BAD;
 
     max_fbpages = (vmm->vram_size / 2) >> PAGE_SHIFT;
 
     fbsize = mode->hdisplay * mode->vdisplay * max_bpp;
     fbpages = DIV_ROUND_UP(fbsize, PAGE_SIZE);
 
     if (fbpages > max_fbpages)
         return MODE_MEM;
 
     return MODE_OK;
 }
 
 /**
  * drm_vram_helper_mode_valid - Tests if a display mode's
  *  framebuffer fits into the available video memory.
  * @dev:    the DRM device
  * @mode:   the mode to test
  *
  * This function tests if enough video memory is available for using the
  * specified display mode. Atomic modesetting requires importing the
  * designated framebuffer into video memory before evicting the active
  * one. Hence, any framebuffer may consume at most half of the available
  * VRAM. Display modes that require a larger framebuffer can not be used,
  * even if the CRTC does support them. Each framebuffer is assumed to
  * have 32-bit color depth.
  *
  * Note:
  * The function can only test if the display mode is supported in
  * general. If there are too many framebuffers pinned to video memory,
  * a display mode may still not be usable in practice. The color depth of
  * 32-bit fits all current use case. A more flexible test can be added
  * when necessary.
  *
  * Returns:
  * MODE_OK if the display mode is supported, or an error code of type
  * enum drm_mode_status otherwise.
  */
 enum drm_mode_status
 drm_vram_helper_mode_valid(struct drm_device *dev,
                const struct drm_display_mode *mode)
 {
     static const unsigned long max_bpp = 4; /* DRM_FORMAT_XRGB8888 */
 
     return drm_vram_helper_mode_valid_internal(dev, mode, max_bpp);
 }
 EXPORT_SYMBOL(drm_vram_helper_mode_valid);
 
 MODULE_DESCRIPTION("DRM VRAM memory-management helpers");
 MODULE_LICENSE("GPL");

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