Quelle  drm_fbdev_dma.c   Sprache: C

// SPDX-License-Identifier: MIT

#include <linux/export.h>
#include <linux/fb.h>
#include <linux/vmalloc.h>

#include <drm/drm_drv.h>
#include <drm/drm_fbdev_dma.h>
#include <drm/drm_fb_dma_helper.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_framebuffer.h>
#include <drm/drm_gem_dma_helper.h>

/*
 * struct fb_ops
 */

static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
{
 struct drm_fb_helper *fb_helper = info->par;

 /* No need to take a ref for fbcon because it unbinds on unregister */
 if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
  return -ENODEV;

 return 0;
}

static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
{
 struct drm_fb_helper *fb_helper = info->par;

 if (user)
  module_put(fb_helper->dev->driver->fops->owner);

 return 0;
}

static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
 struct drm_fb_helper *fb_helper = info->par;

 return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
}

static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
{
 struct drm_fb_helper *fb_helper = info->par;

 if (!fb_helper->dev)
  return;

 if (info->fbdefio)
  fb_deferred_io_cleanup(info);
 drm_fb_helper_fini(fb_helper);

 drm_client_buffer_vunmap(fb_helper->buffer);
 drm_client_framebuffer_delete(fb_helper->buffer);
 drm_client_release(&fb_helper->client);
 drm_fb_helper_unprepare(fb_helper);
 kfree(fb_helper);
}

static const struct fb_ops drm_fbdev_dma_fb_ops = {
 .owner = THIS_MODULE,
 .fb_open = drm_fbdev_dma_fb_open,
 .fb_release = drm_fbdev_dma_fb_release,
 __FB_DEFAULT_DMAMEM_OPS_RDWR,
 DRM_FB_HELPER_DEFAULT_OPS,
 __FB_DEFAULT_DMAMEM_OPS_DRAW,
 .fb_mmap = drm_fbdev_dma_fb_mmap,
 .fb_destroy = drm_fbdev_dma_fb_destroy,
};

FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma_shadowed,
       drm_fb_helper_damage_range,
       drm_fb_helper_damage_area);

static void drm_fbdev_dma_shadowed_fb_destroy(struct fb_info *info)
{
 struct drm_fb_helper *fb_helper = info->par;
 void *shadow = info->screen_buffer;

 if (!fb_helper->dev)
  return;

 if (info->fbdefio)
  fb_deferred_io_cleanup(info);
 drm_fb_helper_fini(fb_helper);
 vfree(shadow);

 drm_client_buffer_vunmap(fb_helper->buffer);
 drm_client_framebuffer_delete(fb_helper->buffer);
 drm_client_release(&fb_helper->client);
 drm_fb_helper_unprepare(fb_helper);
 kfree(fb_helper);
}

static const struct fb_ops drm_fbdev_dma_shadowed_fb_ops = {
 .owner = THIS_MODULE,
 .fb_open = drm_fbdev_dma_fb_open,
 .fb_release = drm_fbdev_dma_fb_release,
 FB_DEFAULT_DEFERRED_OPS(drm_fbdev_dma_shadowed),
 DRM_FB_HELPER_DEFAULT_OPS,
 .fb_destroy = drm_fbdev_dma_shadowed_fb_destroy,
};

/*
 * struct drm_fb_helper
 */

static void drm_fbdev_dma_damage_blit_real(struct drm_fb_helper *fb_helper,
        struct drm_clip_rect *clip,
        struct iosys_map *dst)
{
 struct drm_framebuffer *fb = fb_helper->fb;
 size_t offset = clip->y1 * fb->pitches[0];
 size_t len = clip->x2 - clip->x1;
 unsigned int y;
 void *src;

 switch (drm_format_info_bpp(fb->format, 0)) {
 case 1:
  offset += clip->x1 / 8;
  len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
  break;
 case 2:
  offset += clip->x1 / 4;
  len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
  break;
 case 4:
  offset += clip->x1 / 2;
  len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
  break;
 default:
  offset += clip->x1 * fb->format->cpp[0];
  len *= fb->format->cpp[0];
  break;
 }

 src = fb_helper->info->screen_buffer + offset;
 iosys_map_incr(dst, offset); /* go to first pixel within clip rect */

 for (y = clip->y1; y < clip->y2; y++) {
  iosys_map_memcpy_to(dst, 0, src, len);
  iosys_map_incr(dst, fb->pitches[0]);
  src += fb->pitches[0];
 }
}

static int drm_fbdev_dma_damage_blit(struct drm_fb_helper *fb_helper,
         struct drm_clip_rect *clip)
{
 struct drm_client_buffer *buffer = fb_helper->buffer;
 struct iosys_map dst;

 /*
 * For fbdev emulation, we only have to protect against fbdev modeset
 * operations. Nothing else will involve the client buffer's BO. So it
 * is sufficient to acquire struct drm_fb_helper.lock here.
 */
 mutex_lock(&fb_helper->lock);

 dst = buffer->map;
 drm_fbdev_dma_damage_blit_real(fb_helper, clip, &dst);

 mutex_unlock(&fb_helper->lock);

 return 0;
}
static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper,
      struct drm_clip_rect *clip)
{
 struct drm_device *dev = helper->dev;
 int ret;

 /* Call damage handlers only if necessary */
 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
  return 0;

 if (helper->fb->funcs->dirty) {
  ret = drm_fbdev_dma_damage_blit(helper, clip);
  if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
   return ret;

  ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
  if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
   return ret;
 }

 return 0;
}

static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
 .fb_dirty = drm_fbdev_dma_helper_fb_dirty,
};

/*
 * struct drm_fb_helper
 */

static int drm_fbdev_dma_driver_fbdev_probe_tail(struct drm_fb_helper *fb_helper,
       struct drm_fb_helper_surface_size *sizes)
{
 struct drm_device *dev = fb_helper->dev;
 struct drm_client_buffer *buffer = fb_helper->buffer;
 struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(buffer->gem);
 struct drm_framebuffer *fb = fb_helper->fb;
 struct fb_info *info = fb_helper->info;
 struct iosys_map map = buffer->map;

 info->fbops = &drm_fbdev_dma_fb_ops;

 /* screen */
 info->flags |= FBINFO_VIRTFB; /* system memory */
 if (dma_obj->map_noncoherent)
  info->flags |= FBINFO_READS_FAST; /* signal caching */
 info->screen_size = sizes->surface_height * fb->pitches[0];
 info->screen_buffer = map.vaddr;
 if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
  if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
   info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
 }
 info->fix.smem_len = info->screen_size;

 return 0;
}

static int drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(struct drm_fb_helper *fb_helper,
         struct drm_fb_helper_surface_size *sizes)
{
 struct drm_client_buffer *buffer = fb_helper->buffer;
 struct fb_info *info = fb_helper->info;
 size_t screen_size = buffer->gem->size;
 void *screen_buffer;
 int ret;

 /*
 * Deferred I/O requires struct page for framebuffer memory,
 * which is not guaranteed for all DMA ranges. We thus create
 * a shadow buffer in system memory.
 */
 screen_buffer = vzalloc(screen_size);
 if (!screen_buffer)
  return -ENOMEM;

 info->fbops = &drm_fbdev_dma_shadowed_fb_ops;

 /* screen */
 info->flags |= FBINFO_VIRTFB; /* system memory */
 info->flags |= FBINFO_READS_FAST; /* signal caching */
 info->screen_buffer = screen_buffer;
 info->fix.smem_len = screen_size;

 fb_helper->fbdefio.delay = HZ / 20;
 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;

 info->fbdefio = &fb_helper->fbdefio;
 ret = fb_deferred_io_init(info);
 if (ret)
  goto err_vfree;

 return 0;

err_vfree:
 vfree(screen_buffer);
 return ret;
}

int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
         struct drm_fb_helper_surface_size *sizes)
{
 struct drm_client_dev *client = &fb_helper->client;
 struct drm_device *dev = fb_helper->dev;
 struct drm_client_buffer *buffer;
 struct drm_framebuffer *fb;
 struct fb_info *info;
 u32 format;
 struct iosys_map map;
 int ret;

 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
      sizes->surface_width, sizes->surface_height,
      sizes->surface_bpp);

 format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
          sizes->surface_depth);
 buffer = drm_client_framebuffer_create(client, sizes->surface_width,
            sizes->surface_height, format);
 if (IS_ERR(buffer))
  return PTR_ERR(buffer);

 fb = buffer->fb;

 ret = drm_client_buffer_vmap(buffer, &map);
 if (ret) {
  goto err_drm_client_buffer_delete;
 } else if (drm_WARN_ON(dev, map.is_iomem)) {
  ret = -ENODEV; /* I/O memory not supported; use generic emulation */
  goto err_drm_client_buffer_delete;
 }

 fb_helper->funcs = &drm_fbdev_dma_helper_funcs;
 fb_helper->buffer = buffer;
 fb_helper->fb = fb;

 info = drm_fb_helper_alloc_info(fb_helper);
 if (IS_ERR(info)) {
  ret = PTR_ERR(info);
  goto err_drm_client_buffer_vunmap;
 }

 drm_fb_helper_fill_info(info, fb_helper, sizes);

 if (fb->funcs->dirty)
  ret = drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(fb_helper, sizes);
 else
  ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
 if (ret)
  goto err_drm_fb_helper_release_info;

 return 0;

err_drm_fb_helper_release_info:
 drm_fb_helper_release_info(fb_helper);
err_drm_client_buffer_vunmap:
 fb_helper->fb = NULL;
 fb_helper->buffer = NULL;
 drm_client_buffer_vunmap(buffer);
err_drm_client_buffer_delete:
 drm_client_framebuffer_delete(buffer);
 return ret;
}
EXPORT_SYMBOL(drm_fbdev_dma_driver_fbdev_probe);