drm/meson: add size and alignment requirements for dumb buffers

The Amlogic SoCs Canvas buffers stride must be aligned on 64bytes
and overall size should be aligned on PAGE width.

Adds a custom dumb_create op to adds these requirements.

Fixes: bbbe775e ("drm: Add support for Amlogic Meson Graphic Controller")
Suggested-by: Sky Zhou <sky.zhou@amlogic.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Sky Zhou <sky.zhou@amlogic.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190408090137.2402-1-narmstrong@baylibre.com

drivers/gpu/drm/meson/meson_drv.c

@@ -90,6 +90,18 @@ static irqreturn_t meson_irq(int irq, void *arg)
 	return IRQ_HANDLED;
 }
 
+static int meson_dumb_create(struct drm_file *file, struct drm_device *dev,
+			     struct drm_mode_create_dumb *args)
+{
+	/*
+	 * We need 64bytes aligned stride, and PAGE aligned size
+	 */
+	args->pitch = ALIGN(DIV_ROUND_UP(args->width * args->bpp, 8), SZ_64);
+	args->size = PAGE_ALIGN(args->pitch * args->height);
+
+	return drm_gem_cma_dumb_create_internal(file, dev, args);
+}
+
 DEFINE_DRM_GEM_CMA_FOPS(fops);
 
 static struct drm_driver meson_driver = {
@@ -112,7 +124,7 @@ static struct drm_driver meson_driver = {
 	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
 
 	/* GEM Ops */
-	.dumb_create		= drm_gem_cma_dumb_create,
+	.dumb_create		= meson_dumb_create,
 	.gem_free_object_unlocked = drm_gem_cma_free_object,
 	.gem_vm_ops		= &drm_gem_cma_vm_ops,