sunxi: video: Set input sync enable

Add a write to the "unknown" (*) register to enable auto input sync, when
initially adding sunxi hdmi output support this magic write from the android
kernel code was missed, causing lcdc -> hdmi encoder sync problems.

With this write added, we can drop the modesetting retries and the extra
delays added to work around these sync problems.

With the retries dropped there also is no need to 0 all the enable flags at
the beginning of the modeset, as they are initialized to 0 already by
engines_init.

*) "unknown" is the actual name of this register in the android kernel sources

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
Acked-by: Anatolij Gustschin <agust@denx.de>

arch/arm/include/asm/arch-sunxi/display.h

@@ -236,6 +236,7 @@ struct sunxi_hdmi_reg {
 
 #define SUNXI_HDMI_PKT_CTRL0			0x00000f21
 #define SUNXI_HDMI_PKT_CTRL1			0x0000000f
+#define SUNXI_HDMI_UNKNOWN_INPUT_SYNC		0x08000000
 
 #ifdef CONFIG_MACH_SUN6I
 #define SUNXI_HMDI_DDC_CTRL_ENABLE		(1 << 0)

drivers/video/sunxi_display.c

@@ -501,6 +501,9 @@ static void sunxi_hdmi_mode_set(const struct ctfb_res_modes *mode,
 	if (hdmi_mode)
 		sunxi_hdmi_setup_info_frames(mode);
 
+	/* Set input sync enable */
+	writel(SUNXI_HDMI_UNKNOWN_INPUT_SYNC, &hdmi->unknown);
+
 	/* Init various registers, select pll3 as clock source */
 	writel(SUNXI_HDMI_VIDEO_POL_TX_CLK, &hdmi->video_polarity);
 	writel(SUNXI_HDMI_PAD_CTRL0_RUN, &hdmi->pad_ctrl0);
@@ -556,41 +559,19 @@ static void sunxi_mode_set(const struct ctfb_res_modes *mode, char *monitor,
 	struct sunxi_hdmi_reg * const hdmi =
 		(struct sunxi_hdmi_reg *)SUNXI_HDMI_BASE;
 	int clk_div, clk_double;
-	int retries = 3;
 	bool hdmi_mode = strcmp(monitor, "hdmi") == 0;
 
-retry:
-	clrbits_le32(&hdmi->video_ctrl, SUNXI_HDMI_VIDEO_CTRL_ENABLE);
-	clrbits_le32(&lcdc->ctrl, SUNXI_LCDC_CTRL_TCON_ENABLE);
-	clrbits_le32(&de_be->mode, SUNXI_DE_BE_MODE_START);
-
 	sunxi_composer_mode_set(mode, address);
 	sunxi_lcdc_mode_set(mode, &clk_div, &clk_double);
 	sunxi_hdmi_mode_set(mode, hdmi_mode, clk_div, clk_double);
 
 	setbits_le32(&de_be->reg_ctrl, SUNXI_DE_BE_REG_CTRL_LOAD_REGS);
 	setbits_le32(&de_be->mode, SUNXI_DE_BE_MODE_START);
-
-	udelay(1000000 / mode->refresh + 500);
-
 	setbits_le32(&lcdc->ctrl, SUNXI_LCDC_CTRL_TCON_ENABLE);
 
-	udelay(1000000 / mode->refresh + 500);
+	udelay(100);
 
 	setbits_le32(&hdmi->video_ctrl, SUNXI_HDMI_VIDEO_CTRL_ENABLE);
-
-	udelay(1000000 / mode->refresh + 500);
-
-	/*
-	 * Sometimes the display pipeline does not sync up properly, if
-	 * this happens the hdmi fifo underrun or overrun bits are set.
-	 */
-	if (readl(&hdmi->irq) &
-	    (SUNXI_HDMI_IRQ_STATUS_FIFO_UF | SUNXI_HDMI_IRQ_STATUS_FIFO_OF)) {
-		if (retries--)
-			goto retry;
-		printf("HDMI fifo under or overrun\n");
-	}
 }
 
 void *video_hw_init(void)