[PATCH v2 13/22] drm/exynos: fix clipping when scaling is enabled

[Marek Szyprowski]

This patch fixes calculation of src x/y offset for negative crtc x/y
values when scaling is enabled. This fixes possible IOMMU fault when
scaling is enabled.

Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_drm_plane.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_plane.c 
b/drivers/gpu/drm/exynos/exynos_drm_plane.c
index 9eaa8627175f..427aeec78a28 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_plane.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_plane.c
@@ -85,25 +85,26 @@ static void exynos_plane_mode_set(struct 
exynos_drm_plane_state *exynos_state)
        src_w = state->src_w >> 16;
        src_h = state->src_h >> 16;

+       /* set ratio */
+       exynos_state->h_ratio = (src_w << 16) / crtc_w;
+       exynos_state->v_ratio = (src_h << 16) / crtc_h;
+
+       /* clip to visible area */
        actual_w = exynos_plane_get_size(crtc_x, crtc_w, mode->hdisplay);
        actual_h = exynos_plane_get_size(crtc_y, crtc_h, mode->vdisplay);

        if (crtc_x < 0) {
                if (actual_w)
-                       src_x -= crtc_x;
+                       src_x += ((-crtc_x) * exynos_state->h_ratio) >> 16;
                crtc_x = 0;
        }

        if (crtc_y < 0) {
                if (actual_h)
-                       src_y -= crtc_y;
+                       src_y += ((-crtc_y) * exynos_state->v_ratio) >> 16;
                crtc_y = 0;
        }

-       /* set ratio */
-       exynos_state->h_ratio = (src_w << 16) / crtc_w;
-       exynos_state->v_ratio = (src_h << 16) / crtc_h;
-
        /* set drm framebuffer data. */
        exynos_state->src.x = src_x;
        exynos_state->src.y = src_y;
-- 
1.9.2