imx-drm: ipuv3-plane: enable double buffering

This allows to update the buffer base address while the DMA
channel is running. It is needed to flip the frame buffer of
an active plane.

Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/imx-drm/ipuv3-plane.c b/drivers/staging/imx-drm/ipuv3-plane.c
index 85f49e6..16134d9 100644 (file)
--- a/drivers/staging/imx-drm/ipuv3-plane.c
+++ b/drivers/staging/imx-drm/ipuv3-plane.c
@@ -64,6 +64,7 @@ int ipu_plane_set_base(struct ipu_plane *ipu_plane, struct drm_framebuffer *fb,
 {
        struct drm_gem_cma_object *cma_obj;
        unsigned long eba;
+       int active;
 
        cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
        if (!cma_obj) {
@@ -76,8 +77,15 @@ int ipu_plane_set_base(struct ipu_plane *ipu_plane, struct drm_framebuffer *fb,
 
        eba = cma_obj->paddr + fb->offsets[0] +
              fb->pitches[0] * y + (fb->bits_per_pixel >> 3) * x;
-       ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 0, eba);
-       ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 1, eba);
+
+       if (ipu_plane->enabled) {
+               active = ipu_idmac_get_current_buffer(ipu_plane->ipu_ch);
+               ipu_cpmem_set_buffer(ipu_plane->ipu_ch, !active, eba);
+               ipu_idmac_select_buffer(ipu_plane->ipu_ch, !active);
+       } else {
+               ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 0, eba);
+               ipu_cpmem_set_buffer(ipu_plane->ipu_ch, 1, eba);
+       }
 
        /* cache offsets for subsequent pageflips */
        ipu_plane->x = x;
@@ -187,6 +195,7 @@ int ipu_plane_mode_set(struct ipu_plane *ipu_plane, struct drm_crtc *crtc,
                return ret;
        }
        ipu_cpmem_set_high_priority(ipu_plane->ipu_ch);
+       ipu_idmac_set_double_buffer(ipu_plane->ipu_ch, 1);
        ipu_cpmem_set_stride(ipu_plane->ipu_ch, fb->pitches[0]);
 
        ret = ipu_plane_set_base(ipu_plane, fb, src_x, src_y);