[PATCH] drm/imx: ipuv3-plane: enforce the same physical base address for multiplanar formats

[Philipp Zabel]

The IPU IDMAC handles multiplanar formats using a base address and relative
offsets for the secondary planes. Since those offsets must be positive
and not too large and can't be changed when doing a page flip while scanout
is active, just enforce the same physical base address on all planes.

Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
---
 drivers/gpu/drm/imx/ipuv3-plane.c | 39 +++++++++++++++++++++++++++++++--------
 1 file changed, 31 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/imx/ipuv3-plane.c b/drivers/gpu/drm/imx/ipuv3-plane.c
index 878a643..435eec1 100644
--- a/drivers/gpu/drm/imx/ipuv3-plane.c
+++ b/drivers/gpu/drm/imx/ipuv3-plane.c
@@ -62,22 +62,45 @@ static inline int calc_bandwidth(int width, int height, unsigned int vref)
 int ipu_plane_set_base(struct ipu_plane *ipu_plane, struct drm_framebuffer *fb,
 		       int x, int y)
 {
-	struct drm_gem_cma_object *cma_obj;
+	struct drm_gem_cma_object *cma_obj[3];
 	unsigned long eba;
-	int active;
+	int active, i;
 
-	cma_obj = drm_fb_cma_get_gem_obj(fb, 0);
-	if (!cma_obj) {
-		DRM_DEBUG_KMS("entry is null.\n");
-		return -EFAULT;
+	for (i = 0; i < drm_format_num_planes(fb->pixel_format); i++) {
+		cma_obj[i] = drm_fb_cma_get_gem_obj(fb, i);
+		if (!cma_obj[i]) {
+			DRM_DEBUG_KMS("plane %d entry is null.\n", i);
+			return -EFAULT;
+		}
 	}
 
 	dev_dbg(ipu_plane->base.dev->dev, "phys = %pad, x = %d, y = %d",
-		&cma_obj->paddr, x, y);
+		&cma_obj[0]->paddr, x, y);
 
-	eba = cma_obj->paddr + fb->offsets[0] +
+	eba = cma_obj[0]->paddr + fb->offsets[0] +
 	      fb->pitches[0] * y + (fb->bits_per_pixel >> 3) * x;
 
+	switch (fb->pixel_format) {
+	case DRM_FORMAT_YUV420:
+	case DRM_FORMAT_YVU420:
+		/*
+		 * Multiplanar formats have to meet the following restrictions:
+		 * - The (up to) three plane addresses are EBA, EBA+UBO, EBA+VBO
+		 * - EBA, UBO and VBO are a multiple of 8
+		 * - UBO and VBO are unsigned and not larger than 0xfffff8
+		 * - Only EBA may be changed while scanout is active
+		 *
+		 * For now, enforce the same physical base address for all
+		 * planes.
+		 */
+		if (cma_obj[0]->paddr != cma_obj[1]->paddr ||
+		    cma_obj[0]->paddr != cma_obj[2]->paddr) {
+			DRM_DEBUG_KMS("plane base addresses differ.\n");
+			return -EINVAL;
+		}
+		break;
+	}
+
 	if (ipu_plane->enabled) {
 		active = ipu_idmac_get_current_buffer(ipu_plane->ipu_ch);
 		ipu_cpmem_set_buffer(ipu_plane->ipu_ch, !active, eba);
-- 
2.5.0