drm: support for rotated scanout

For drivers that can support rotated scanout, the extra parameter
checking in drm-core, while nice, tends to get confused.  To solve
this drivers can set the crtc or plane invert_dimensions field so
that the dimension checking takes into account the rotation that
the driver is performing.

v1: original
v2: remove invert_dimensions from plane, at Ville's suggestion.
    Userspace can give rotated src coordinates, so invert_dimensions
    is not required for planes.

Signed-off-by: Rob Clark <rob@ti.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 35 insertions, 16 deletions

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 39afe13a5fa2..9c346a50379f 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -437,6 +437,7 @@ int drm_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
 
         crtc->dev = dev;
         crtc->funcs = funcs;
+        crtc->invert_dimensions = false;
 
         mutex_lock(&dev->mode_config.mutex);
 
@@ -1912,6 +1913,7 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
         DRM_DEBUG_KMS("[CRTC:%d]\n", crtc->base.id);
 
         if (crtc_req->mode_valid) {
+                int hdisplay, vdisplay;
                 /* If we have a mode we need a framebuffer. */
                 /* If we pass -1, set the mode with the currently bound fb */
                 if (crtc_req->fb_id == -1) {
@@ -1947,14 +1949,20 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 
                 drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
 
-                if (mode->hdisplay > fb->width ||
-                    mode->vdisplay > fb->height ||
-                    crtc_req->x > fb->width - mode->hdisplay ||
-                    crtc_req->y > fb->height - mode->vdisplay) {
-                        DRM_DEBUG_KMS("Invalid CRTC viewport %ux%u+%u+%u for fb size %ux%u.\n",
-                                      mode->hdisplay, mode->vdisplay,
-                                      crtc_req->x, crtc_req->y,
-                                      fb->width, fb->height);
+                hdisplay = mode->hdisplay;
+                vdisplay = mode->vdisplay;
+
+                if (crtc->invert_dimensions)
+                        swap(hdisplay, vdisplay);
+
+                if (hdisplay > fb->width ||
+                    vdisplay > fb->height ||
+                    crtc_req->x > fb->width - hdisplay ||
+                    crtc_req->y > fb->height - vdisplay) {
+                        DRM_DEBUG_KMS("Invalid fb size %ux%u for CRTC viewport %ux%u+%d+%d%s.\n",
+                                      fb->width, fb->height,
+                                      hdisplay, vdisplay, crtc_req->x, crtc_req->y,
+                                      crtc->invert_dimensions ? " (inverted)" : "");
                         ret = -ENOSPC;
                         goto out;
                 }
@@ -3546,6 +3554,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
         struct drm_framebuffer *fb;
         struct drm_pending_vblank_event *e = NULL;
         unsigned long flags;
+        int hdisplay, vdisplay;
         int ret = -EINVAL;
 
         if (page_flip->flags & ~DRM_MODE_PAGE_FLIP_FLAGS ||
@@ -3575,14 +3584,19 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
                 goto out;
         fb = obj_to_fb(obj);
 
-        if (crtc->mode.hdisplay > fb->width ||
-            crtc->mode.vdisplay > fb->height ||
-            crtc->x > fb->width - crtc->mode.hdisplay ||
-            crtc->y > fb->height - crtc->mode.vdisplay) {
-                DRM_DEBUG_KMS("Invalid fb size %ux%u for CRTC viewport %ux%u+%d+%d.\n",
-                              fb->width, fb->height,
-                              crtc->mode.hdisplay, crtc->mode.vdisplay,
-                              crtc->x, crtc->y);
+        hdisplay = crtc->mode.hdisplay;
+        vdisplay = crtc->mode.vdisplay;
+
+        if (crtc->invert_dimensions)
+                swap(hdisplay, vdisplay);
+
+        if (hdisplay > fb->width ||
+            vdisplay > fb->height ||
+            crtc->x > fb->width - hdisplay ||
+            crtc->y > fb->height - vdisplay) {
+                DRM_DEBUG_KMS("Invalid fb size %ux%u for CRTC viewport %ux%u+%d+%d%s.\n",
+                              fb->width, fb->height, hdisplay, vdisplay, crtc->x, crtc->y,
+                              crtc->invert_dimensions ? " (inverted)" : "");
                 ret = -ENOSPC;
                 goto out;
         }
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index 68fdb299e39f..8e405b82707d 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -368,6 +368,9 @@ struct drm_crtc_funcs {
  * @enabled: is this CRTC enabled?
  * @mode: current mode timings
  * @hwmode: mode timings as programmed to hw regs
+ * @invert_dimensions: for purposes of error checking crtc vs fb sizes,
+ *    invert the width/height of the crtc.  This is used if the driver
+ *    is performing 90 or 270 degree rotated scanout
  * @x: x position on screen
  * @y: y position on screen
  * @funcs: CRTC control functions
@@ -401,6 +404,8 @@ struct drm_crtc {
          */
         struct drm_display_mode hwmode;
 
+        bool invert_dimensions;
+
         int x, y;
         const struct drm_crtc_funcs *funcs;