1 files changed, 323 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fbdev_dma.c b/drivers/gpu/drm/drm_fbdev_dma.c
new file mode 100644
index 000000000000..9412d9fdd74b
--- /dev/null
+++ b/drivers/gpu/drm/drm_fbdev_dma.c
@@ -0,0 +1,323 @@
+// 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>
+#include <drm/drm_print.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_buffer_delete(fb_helper->buffer);
+	drm_client_release(&fb_helper->client);
+}
+
+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_buffer_delete(fb_helper->buffer);
+	drm_client_release(&fb_helper->client);
+}
+
+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 fb_info *info = fb_helper->info;
+	struct drm_client_buffer *buffer;
+	struct drm_framebuffer *fb;
+	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_buffer_create_dumb(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;
+
+	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_client_buffer_vunmap;
+
+	return 0;
+
+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_buffer_delete(buffer);
+	return ret;
+}
+EXPORT_SYMBOL(drm_fbdev_dma_driver_fbdev_probe);