drm/armada: disable planes at next blanking period

Disable planes at the next blanking period rather than immediately.
In order to achieve this, we need to delay the clearing of dcrtc->plane
until after the next blanking period, so move that into a separate
work function.  To avoid races, we also need to move its assignment in
the overlay code.

Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

2 files changed, 50 insertions, 32 deletions

diff --git a/drivers/gpu/drm/armada/armada_crtc.c b/drivers/gpu/drm/armada/armada_crtc.c
index 98fb955f6889..c38a1409a14e 100644
--- a/drivers/gpu/drm/armada/armada_crtc.c
+++ b/drivers/gpu/drm/armada/armada_crtc.c
@@ -293,6 +293,19 @@ static void armada_drm_crtc_complete_frame_work(struct armada_crtc *dcrtc,
         spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
 }
 
+static void armada_drm_crtc_complete_disable_work(struct armada_crtc *dcrtc,
+        struct armada_plane_work *work)
+{
+        unsigned long flags;
+
+        if (dcrtc->plane == work->plane)
+                dcrtc->plane = NULL;
+
+        spin_lock_irqsave(&dcrtc->irq_lock, flags);
+        armada_drm_crtc_update_regs(dcrtc, work->regs);
+        spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
+}
+
 static struct armada_plane_work *
 armada_drm_crtc_alloc_plane_work(struct drm_plane *plane)
 {
@@ -392,8 +405,11 @@ static void armada_drm_crtc_prepare(struct drm_crtc *crtc)
          * the new mode parameters.
          */
         plane = dcrtc->plane;
-        if (plane)
+        if (plane) {
                 drm_plane_force_disable(plane);
+                WARN_ON(!armada_drm_plane_work_wait(drm_to_armada_plane(plane),
+                                                    HZ));
+        }
 }
 
 /* The mode_config.mutex will be held for this call */
@@ -1120,28 +1136,22 @@ int armada_drm_plane_disable(struct drm_plane *plane,
 {
         struct armada_plane *dplane = drm_to_armada_plane(plane);
         struct armada_crtc *dcrtc;
+        struct armada_plane_work *work;
+        unsigned int idx = 0;
         u32 sram_para1, enable_mask;
 
         if (!plane->crtc)
                 return 0;
 
         /*
-         * Drop our reference on any framebuffer attached to this plane.
-         * We don't need to NULL this out as drm_plane_force_disable(),
-         * and __setplane_internal() will do so for an overlay plane, and
-         * __drm_helper_disable_unused_functions() will do so for the
-         * primary plane.
+         * Arrange to power down most RAMs and FIFOs if this is the primary
+         * plane, otherwise just the YUV FIFOs for the overlay plane.
          */
-        if (plane->fb)
-                drm_framebuffer_put(plane->fb);
-
-        /* Power down most RAMs and FIFOs if this is the primary plane */
         if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
                 sram_para1 = CFG_PDWN256x32 | CFG_PDWN256x24 | CFG_PDWN256x8 |
                              CFG_PDWN32x32 | CFG_PDWN64x66;
                 enable_mask = CFG_GRA_ENA;
         } else {
-                /* Power down the Y/U/V FIFOs */
                 sram_para1 = CFG_PDWN16x66 | CFG_PDWN32x66;
                 enable_mask = CFG_DMA_ENA;
         }
@@ -1150,14 +1160,33 @@ int armada_drm_plane_disable(struct drm_plane *plane,
 
         dcrtc = drm_to_armada_crtc(plane->crtc);
 
+        /*
+         * Try to disable the plane and drop our ref on the framebuffer
+         * at the next frame update. If we fail for any reason, disable
+         * the plane immediately.
+         */
+        work = &dplane->works[dplane->next_work];
+        work->fn = armada_drm_crtc_complete_disable_work;
+        work->cancel = armada_drm_crtc_complete_disable_work;
+        work->old_fb = plane->fb;
+
+        armada_reg_queue_mod(work->regs, idx,
+                             0, enable_mask, LCD_SPU_DMA_CTRL0);
+        armada_reg_queue_mod(work->regs, idx,
+                             sram_para1, 0, LCD_SPU_SRAM_PARA1);
+        armada_reg_queue_end(work->regs, idx);
+
         /* Wait for any preceding work to complete, but don't wedge */
         if (WARN_ON(!armada_drm_plane_work_wait(dplane, HZ)))
                 armada_drm_plane_work_cancel(dcrtc, dplane);
 
-        spin_lock_irq(&dcrtc->irq_lock);
-        armada_updatel(0, enable_mask, dcrtc->base + LCD_SPU_DMA_CTRL0);
-        armada_updatel(sram_para1, 0, dcrtc->base + LCD_SPU_SRAM_PARA1);
-        spin_unlock_irq(&dcrtc->irq_lock);
+        if (armada_drm_plane_work_queue(dcrtc, work)) {
+                work->fn(dcrtc, work);
+                if (work->old_fb)
+                        drm_framebuffer_unreference(work->old_fb);
+        }
+
+        dplane->next_work = !dplane->next_work;
 
         return 0;
 }
diff --git a/drivers/gpu/drm/armada/armada_overlay.c b/drivers/gpu/drm/armada/armada_overlay.c
index bad966ae6758..0fe3f2db8ff5 100644
--- a/drivers/gpu/drm/armada/armada_overlay.c
+++ b/drivers/gpu/drm/armada/armada_overlay.c
@@ -140,11 +140,6 @@ armada_ovl_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
                      dplane->base.state.src_x != state.src.x1 >> 16 ||
                      dplane->base.state.src_y != state.src.y1 >> 16;
 
-        if (!dcrtc->plane) {
-                dcrtc->plane = plane;
-                armada_ovl_update_attr(&dplane->prop, dcrtc);
-        }
-
         /* FIXME: overlay on an interlaced display */
         /* Just updating the position/size? */
         if (!fb_changed && dplane->base.state.ctrl0 == ctrl0) {
@@ -173,6 +168,11 @@ armada_ovl_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
         if (armada_drm_plane_work_wait(&dplane->base, HZ / 25) == 0)
                 armada_drm_plane_work_cancel(dcrtc, &dplane->base);
 
+        if (!dcrtc->plane) {
+                dcrtc->plane = plane;
+                armada_ovl_update_attr(&dplane->prop, dcrtc);
+        }
+
         if (fb_changed) {
                 u32 addrs[3];
 
@@ -255,17 +255,6 @@ armada_ovl_plane_update(struct drm_plane *plane, struct drm_crtc *crtc,
         return 0;
 }
 
-static int armada_ovl_plane_disable(struct drm_plane *plane,
-                                    struct drm_modeset_acquire_ctx *ctx)
-{
-        armada_drm_plane_disable(plane, ctx);
-
-        if (plane->crtc)
-                drm_to_armada_crtc(plane->crtc)->plane = NULL;
-
-        return 0;
-}
-
 static void armada_ovl_plane_destroy(struct drm_plane *plane)
 {
         struct armada_ovl_plane *dplane = drm_to_armada_ovl_plane(plane);
@@ -345,7 +334,7 @@ static int armada_ovl_plane_set_property(struct drm_plane *plane,
 
 static const struct drm_plane_funcs armada_ovl_plane_funcs = {
         .update_plane   = armada_ovl_plane_update,
-        .disable_plane  = armada_ovl_plane_disable,
+        .disable_plane  = armada_drm_plane_disable,
         .destroy        = armada_ovl_plane_destroy,
         .set_property   = armada_ovl_plane_set_property,
 };