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>

arch/arm/plat-samsung/include/plat/regs-fb.h

@@ -223,6 +223,10 @@
 /* S5PV210 */
 #define SHADOWCON				(0x34)
 #define SHADOWCON_WINx_PROTECT(_win)		(1 << (10 + (_win)))
+/* DMA channels (all windows) */
+#define SHADOWCON_CHx_ENABLE(_win)		(1 << (_win))
+/* Local input channels (windows 0-2) */
+#define SHADOWCON_CHx_LOCAL_ENABLE(_win)	(1 << (5 + (_win)))
 
 #define VIDOSDxA_TOPLEFT_X_MASK			(0x7ff << 11)
 #define VIDOSDxA_TOPLEFT_X_SHIFT		(11)

drivers/video/s3c-fb.c

@@ -634,6 +634,13 @@ static int s3c_fb_set_par(struct fb_info *info)
 	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_free_memory(struct s3c_fb *sfb, struct s3c_fb_win *win)
  */
 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);