1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_fbdev_ttm.c b/drivers/gpu/drm/drm_fbdev_ttm.c
new file mode 100644
index 000000000000..73d35d59590c
--- /dev/null
+++ b/drivers/gpu/drm/drm_fbdev_ttm.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: MIT
+
+#include <linux/moduleparam.h>
+#include <linux/vmalloc.h>
+
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_gem.h>
+#include <drm/drm_print.h>
+
+#include <drm/drm_fbdev_ttm.h>
+
+/* @user: 1=userspace, 0=fbcon */
+static int drm_fbdev_ttm_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_ttm_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;
+}
+
+FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_ttm,
+				   drm_fb_helper_damage_range,
+				   drm_fb_helper_damage_area);
+
+static void drm_fbdev_ttm_fb_destroy(struct fb_info *info)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	void *shadow = info->screen_buffer;
+
+	if (!fb_helper->dev)
+		return;
+
+	fb_deferred_io_cleanup(info);
+	drm_fb_helper_fini(fb_helper);
+	vfree(shadow);
+	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_ttm_fb_ops = {
+	.owner		= THIS_MODULE,
+	.fb_open	= drm_fbdev_ttm_fb_open,
+	.fb_release	= drm_fbdev_ttm_fb_release,
+	FB_DEFAULT_DEFERRED_OPS(drm_fbdev_ttm),
+	DRM_FB_HELPER_DEFAULT_OPS,
+	.fb_destroy	= drm_fbdev_ttm_fb_destroy,
+};
+
+static void drm_fbdev_ttm_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_ttm_damage_blit(struct drm_fb_helper *fb_helper,
+				     struct drm_clip_rect *clip)
+{
+	struct drm_client_buffer *buffer = fb_helper->buffer;
+	struct iosys_map map, dst;
+	int ret;
+
+	/*
+	 * We have to pin the client buffer to its current location while
+	 * flushing the shadow buffer. In the general case, concurrent
+	 * modesetting operations could try to move the buffer and would
+	 * fail. The modeset has to be serialized by acquiring the reservation
+	 * object of the underlying BO here.
+	 *
+	 * 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);
+
+	ret = drm_client_buffer_vmap_local(buffer, &map);
+	if (ret)
+		goto out;
+
+	dst = map;
+	drm_fbdev_ttm_damage_blit_real(fb_helper, clip, &dst);
+
+	drm_client_buffer_vunmap_local(buffer);
+
+out:
+	mutex_unlock(&fb_helper->lock);
+
+	return ret;
+}
+
+static int drm_fbdev_ttm_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;
+
+	ret = drm_fbdev_ttm_damage_blit(helper, clip);
+	if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
+		return ret;
+
+	if (helper->fb->funcs->dirty) {
+		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_ttm_helper_funcs = {
+	.fb_dirty = drm_fbdev_ttm_helper_fb_dirty,
+};
+
+/*
+ * struct drm_driver
+ */
+
+int drm_fbdev_ttm_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 fb_info *info;
+	size_t screen_size;
+	void *screen_buffer;
+	u32 format;
+	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_helper->funcs = &drm_fbdev_ttm_helper_funcs;
+	fb_helper->buffer = buffer;
+	fb_helper->fb = buffer->fb;
+
+	screen_size = buffer->gem->size;
+	screen_buffer = vzalloc(screen_size);
+	if (!screen_buffer) {
+		ret = -ENOMEM;
+		goto err_drm_client_framebuffer_delete;
+	}
+
+	info = drm_fb_helper_alloc_info(fb_helper);
+	if (IS_ERR(info)) {
+		ret = PTR_ERR(info);
+		goto err_vfree;
+	}
+
+	drm_fb_helper_fill_info(info, fb_helper, sizes);
+
+	info->fbops = &drm_fbdev_ttm_fb_ops;
+
+	/* screen */
+	info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
+	info->screen_buffer = screen_buffer;
+	info->fix.smem_len = screen_size;
+
+	/* deferred I/O */
+	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_drm_fb_helper_release_info;
+
+	return 0;
+
+err_drm_fb_helper_release_info:
+	drm_fb_helper_release_info(fb_helper);
+err_vfree:
+	vfree(screen_buffer);
+err_drm_client_framebuffer_delete:
+	fb_helper->fb = NULL;
+	fb_helper->buffer = NULL;
+	drm_client_framebuffer_delete(buffer);
+	return ret;
+}
+EXPORT_SYMBOL(drm_fbdev_ttm_driver_fbdev_probe);