drm/rockchip: shutdown drm subsystem on shutdown

As explained by Robin Murphy:
> the IOMMU shutdown disables paging, so if the VOP is still
> scanning out then that will result in whatever IOVAs it was using now going
> straight out onto the bus as physical addresses.

We had a more radical approach before in commit
7f3ef5dedb14 ("drm/rockchip: Allow driver to be shutdown on reboot/kexec")
but that resulted in new warnings and oopses on shutdown on rk3399
chromeos devices.

So second try is resurrecting Vicentes shutdown change which should
achieve the same result but in a less drastic way.

Fixes: 63238173b2fa ("Revert "drm/rockchip: Allow driver to be shutdown on reboot/kexec"")
Cc: Jeffy Chen <jeffy.chen@rock-chips.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Brian Norris <briannorris@chromium.org>
Cc: Doug Anderson <dianders@chromium.org>
Cc: stable@vger.kernel.org
Suggested-by: JeffyChen <jeffy.chen@rock-chips.com>
Suggested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Vicente Bergas <vicencb@gmail.com>
[adapted commit message to explain the history]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Brian Norris <briannorris@chromium.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190402113753.10118-1-heiko@sntech.de

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
index 8d7a634..cb938d3 100644 (file)
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c
@@ -448,6 +448,14 @@ static int rockchip_drm_platform_remove(struct platform_device *pdev)
        return 0;
 }
 
+static void rockchip_drm_platform_shutdown(struct platform_device *pdev)
+{
+       struct drm_device *drm = platform_get_drvdata(pdev);
+
+       if (drm)
+               drm_atomic_helper_shutdown(drm);
+}
+
 static const struct of_device_id rockchip_drm_dt_ids[] = {
        { .compatible = "rockchip,display-subsystem", },
        { /* sentinel */ },
@@ -457,6 +465,7 @@ MODULE_DEVICE_TABLE(of, rockchip_drm_dt_ids);
 static struct platform_driver rockchip_drm_platform_driver = {
        .probe = rockchip_drm_platform_probe,
        .remove = rockchip_drm_platform_remove,
+       .shutdown = rockchip_drm_platform_shutdown,
        .driver = {
                .name = "rockchip-drm",
                .of_match_table = rockchip_drm_dt_ids,