drm/exynos/mixer: fix synchronization check in interlaced mode

In case of interlace mode video processor registers and mixer config
register must be check to ensure internal state is in sync with shadow
registers.
This patch fixes page-faults in interlaced mode.
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

drivers/gpu/drm/exynos/exynos_mixer.c

@@ -482,6 +482,7 @@ static void vp_video_buffer(struct mixer_context *ctx,
 
 	spin_lock_irqsave(&ctx->reg_slock, flags);
 
+	vp_reg_write(ctx, VP_SHADOW_UPDATE, 1);
 	/* interlace or progressive scan mode */
 	val = (test_bit(MXR_BIT_INTERLACE, &ctx->flags) ? ~0 : 0);
 	vp_reg_writemask(ctx, VP_MODE, val, VP_MODE_LINE_SKIP);
@@ -699,6 +700,15 @@ static irqreturn_t mixer_irq_handler(int irq, void *arg)
 
 		/* interlace scan need to check shadow register */
 		if (test_bit(MXR_BIT_INTERLACE, &ctx->flags)) {
+			if (test_bit(MXR_BIT_VP_ENABLED, &ctx->flags) &&
+			    vp_reg_read(ctx, VP_SHADOW_UPDATE))
+				goto out;
+
+			base = mixer_reg_read(ctx, MXR_CFG);
+			shadow = mixer_reg_read(ctx, MXR_CFG_S);
+			if (base != shadow)
+				goto out;
+
 			base = mixer_reg_read(ctx, MXR_GRAPHIC_BASE(0));
 			shadow = mixer_reg_read(ctx, MXR_GRAPHIC_BASE_S(0));
 			if (base != shadow)

drivers/gpu/drm/exynos/regs-mixer.h

@@ -47,6 +47,7 @@
 #define MXR_MO				0x0304
 #define MXR_RESOLUTION			0x0310
 
+#define MXR_CFG_S			0x2004
 #define MXR_GRAPHIC0_BASE_S		0x2024
 #define MXR_GRAPHIC1_BASE_S		0x2044