s3c-fb: add support for DMA channel control on S5PV210

S5PV210 SoCs allow enabling/disabling DMA channels per window.  For a
window to display data from framebuffer memory, its channel has to be
enabled.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: InKi Dae <inki.dae@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
index a95314d..8ea974d 100644
--- a/drivers/video/s3c-fb.c
+++ b/drivers/video/s3c-fb.c
@@ -634,6 +634,13 @@
 	writel(data, regs + sfb->variant.wincon + (win_no * 4));
 	writel(0x0, regs + sfb->variant.winmap + (win_no * 4));
 
+	/* Enable DMA channel for this window */
+	if (sfb->variant.has_shadowcon) {
+		data = readl(sfb->regs + SHADOWCON);
+		data |= SHADOWCON_CHx_ENABLE(win_no);
+		writel(data, sfb->regs + SHADOWCON);
+	}
+
 	shadow_protect_win(win, 0);
 
 	return 0;
@@ -1091,7 +1098,15 @@
  */
 static void s3c_fb_release_win(struct s3c_fb *sfb, struct s3c_fb_win *win)
 {
+	u32 data;
+
 	if (win->fbinfo) {
+		if (sfb->variant.has_shadowcon) {
+			data = readl(sfb->regs + SHADOWCON);
+			data &= ~SHADOWCON_CHx_ENABLE(win->index);
+			data &= ~SHADOWCON_CHx_LOCAL_ENABLE(win->index);
+			writel(data, sfb->regs + SHADOWCON);
+		}
 		unregister_framebuffer(win->fbinfo);
 		if (win->fbinfo->cmap.len)
 			fb_dealloc_cmap(&win->fbinfo->cmap);