drm/mgag200: Replace VRAM helpers with SHMEM helpers

The VRAM helpers managed the framebuffer memory for mgag200. This came
with several problems, as some MGA device require the scanout address
to be located at VRAM offset 0. It's incompatible with the page-flip
semantics of DRM's atomic modesettting. With atomic modesetting, old and
new framebuffers have to be located in VRAM at the same time. So at least
one of them has to reside at a non-0 offset.

This patch replaces VRAM helpers with SHMEM helpers. GEM SHMEM buffers
reside in system memory, and are shadow-copied into VRAM during page
flips. The shadow copy always starts at VRAM offset 0.

v2:
	* revert dev->pdev changes

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: John Donnelly <John.p.donnelly@oracle.com>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200515083233.32036-16-tzimmermann@suse.de

1 files changed, 2 insertions, 47 deletions

diff --git a/drivers/gpu/drm/mgag200/mgag200_drv.c b/drivers/gpu/drm/mgag200/mgag200_drv.c
index a06ce4198ade..00ddea7d7d27 100644
--- a/drivers/gpu/drm/mgag200/mgag200_drv.c
+++ b/drivers/gpu/drm/mgag200/mgag200_drv.c
@@ -22,15 +22,11 @@
  * which then performs further device association and calls our graphics init
  * functions
  */
-int mgag200_modeset = -1;
 
+int mgag200_modeset = -1;
 MODULE_PARM_DESC(modeset, "Disable/Enable modesetting");
 module_param_named(modeset, mgag200_modeset, int, 0400);
 
-int mgag200_hw_bug_no_startadd = -1;
-MODULE_PARM_DESC(modeset, "HW does not interpret scanout-buffer start address correctly");
-module_param_named(hw_bug_no_startadd, mgag200_hw_bug_no_startadd, int, 0400);
-
 static struct drm_driver driver;
 
 static const struct pci_device_id pciidlist[] = {
@@ -101,44 +97,6 @@ static void mga_pci_remove(struct pci_dev *pdev)
 
 DEFINE_DRM_GEM_FOPS(mgag200_driver_fops);
 
-static bool mgag200_pin_bo_at_0(const struct mga_device *mdev)
-{
-	if (mgag200_hw_bug_no_startadd > 0) {
-		DRM_WARN_ONCE("Option hw_bug_no_startradd is enabled. Please "
-			      "report the output of 'lspci -vvnn' to "
-			      "<dri-devel@lists.freedesktop.org> if this "
-			      "option is required to make mgag200 work "
-			      "correctly on your system.\n");
-		return true;
-	} else if (!mgag200_hw_bug_no_startadd) {
-		return false;
-	}
-	return mdev->flags & MGAG200_FLAG_HW_BUG_NO_STARTADD;
-}
-
-int mgag200_driver_dumb_create(struct drm_file *file,
-			       struct drm_device *dev,
-			       struct drm_mode_create_dumb *args)
-{
-	struct mga_device *mdev = to_mga_device(dev);
-	unsigned long pg_align;
-
-	if (WARN_ONCE(!dev->vram_mm, "VRAM MM not initialized"))
-		return -EINVAL;
-
-	pg_align = 0ul;
-
-	/*
-	 * Aligning scanout buffers to the size of the video ram forces
-	 * placement at offset 0. Works around a bug where HW does not
-	 * respect 'startadd' field.
-	 */
-	if (mgag200_pin_bo_at_0(mdev))
-		pg_align = PFN_UP(mdev->mc.vram_size);
-
-	return drm_gem_vram_fill_create_dumb(file, dev, pg_align, 0, args);
-}
-
 static struct drm_driver driver = {
 	.driver_features = DRIVER_ATOMIC | DRIVER_GEM | DRIVER_MODESET,
 	.fops = &mgag200_driver_fops,
@@ -148,10 +106,7 @@ static struct drm_driver driver = {
 	.major = DRIVER_MAJOR,
 	.minor = DRIVER_MINOR,
 	.patchlevel = DRIVER_PATCHLEVEL,
-	.debugfs_init = drm_vram_mm_debugfs_init,
-	.dumb_create = mgag200_driver_dumb_create,
-	.dumb_map_offset = drm_gem_vram_driver_dumb_mmap_offset,
-	.gem_prime_mmap = drm_gem_prime_mmap,
+	DRM_GEM_SHMEM_DRIVER_OPS,
 };
 
 static struct pci_driver mgag200_pci_driver = {