From c7e9de10db4b760bd5d25f4a5c962a96b7d9bfd1 Mon Sep 17 00:00:00 2001
From: Mark yao <mark.yao@rock-chips.com>
Date: Mon, 31 Jul 2017 17:49:42 +0800
Subject: [PATCH 71/86] drm/rockchip: vop: fix iommu page fault when resume

Git-commit: da6c9bbf418dcb0f8be261f4353400fa959b1e92
Patch-mainline: v4.13-rc5
References: fate#323912

Iommu would get page fault with following path:
   vop_disable:
      1, disable all windows and set vop config done
      2, vop enter to standy, all windows not works, but their registers
         are not clean, when you read window's enable bit, may found the
         window is enable.

   vop_enable:
      1, memcpy(vop->regsbak, vop->regs, len)
         save current vop registers to vop->regsbak, then you can found
         window is enable on regsbak.
      2, VOP_WIN_SET(vop, win, gate, 1);
         force enable window gate, but gate and enable are on same
         hardware register, then window enable bit rewrite to vop hardware.
      3, vop power on, and vop might try to scan destroyed buffer,
         then iommu get page fault.

Move windows disable after vop regsbak restore, then vop regsbak mechanism
would keep tracing the modify, everything would be safe.

Signed-off-by: Mark Yao <mark.yao@rock-chips.com>
Reviewed-by: Sandy huang <sandy.huang@rock-chips.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1501494582-6934-1-git-send-email-mark.yao@rock-chips.com
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 33 +++++++++++++----------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index 9b95a0aeab06..f22ff38cae26 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -495,7 +495,7 @@ static void vop_line_flag_irq_disable(struct vop *vop)
 static int vop_enable(struct drm_crtc *crtc)
 {
 	struct vop *vop = to_vop(crtc);
-	int ret;
+	int ret, i;
 
 	ret = pm_runtime_get_sync(vop->dev);
 	if (ret < 0) {
@@ -528,6 +528,20 @@ static int vop_enable(struct drm_crtc *crtc)
 	}
 
 	memcpy(vop->regs, vop->regsbak, vop->len);
+	/*
+	 * We need to make sure that all windows are disabled before we
+	 * enable the crtc. Otherwise we might try to scan from a destroyed
+	 * buffer later.
+	 */
+	for (i = 0; i < vop->data->win_size; i++) {
+		struct vop_win *vop_win = &vop->win[i];
+		const struct vop_win_data *win = vop_win->data;
+
+		spin_lock(&vop->reg_lock);
+		VOP_WIN_SET(vop, win, enable, 0);
+		spin_unlock(&vop->reg_lock);
+	}
+
 	vop_cfg_done(vop);
 
 	/*
@@ -561,28 +575,11 @@ static int vop_enable(struct drm_crtc *crtc)
 static void vop_crtc_disable(struct drm_crtc *crtc)
 {
 	struct vop *vop = to_vop(crtc);
-	int i;
 
 	WARN_ON(vop->event);
 
 	rockchip_drm_psr_deactivate(&vop->crtc);
 
-	/*
-	 * We need to make sure that all windows are disabled before we
-	 * disable that crtc. Otherwise we might try to scan from a destroyed
-	 * buffer later.
-	 */
-	for (i = 0; i < vop->data->win_size; i++) {
-		struct vop_win *vop_win = &vop->win[i];
-		const struct vop_win_data *win = vop_win->data;
-
-		spin_lock(&vop->reg_lock);
-		VOP_WIN_SET(vop, win, enable, 0);
-		spin_unlock(&vop->reg_lock);
-	}
-
-	vop_cfg_done(vop);
-
 	drm_crtc_vblank_off(crtc);
 
 	/*
-- 
2.11.0