rk3288: Auto-detect display.

We currently select either HDMI or EDP (default). This patch
allows us to use HDMI as a fallback for devices that may have
a display connected on either interface. It also renames the
enums to sound a little more sensible in other contexts (more
on that in the follow-up patches).

VOP_MODE_AUTO is added to the mode enum which will make it explicit
that a board can support either. In AUTO_MODE we will try EDP first
and then fallback to HDMI. Other modes can be set to force a certain
behavior such as HDMI-only on Mickey where it doesn't make sense to
try EDP.

A follow-up patch will add logic for when we explicitly don't want
to probe for any display (headless devices).

BUG=none
BRANCH=none
TEST=On veyron_danger, connected EDP and HDMI displays and saw dev
mode screen appear on EDP display. Unplugged EDP and then dev mode
screen showed up on HDMI.

Change-Id: I22b38031c4ab3d79fbb182f7a906da1197f35543
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: 3f57ed3758c4e516d9fd226ad9499b102b81b423
Original-Change-Id: I352dcde16f7f3ebbf5796852b685685e541eb794
Original-Signed-off-by: David Hendricks <dhendrix@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/281076
Original-Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: http://review.coreboot.org/10775
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

4 files changed, 47 insertions, 24 deletions

diff --git a/src/soc/rockchip/rk3288/chip.h b/src/soc/rockchip/rk3288/chip.h
index 3a6b14d21310..2c4390a515c3 100644
--- a/src/soc/rockchip/rk3288/chip.h
+++ b/src/soc/rockchip/rk3288/chip.h
@@ -21,6 +21,7 @@
 #define __SOC_ROCKCHIP_RK3288_CHIP_H__
 
 #include <soc/gpio.h>
+#include <soc/vop.h>	/* for vop_modes enum used in devicetree.cb */
 
 struct soc_rockchip_rk3288_config {
 	u32 vop_id;
diff --git a/src/soc/rockchip/rk3288/display.c b/src/soc/rockchip/rk3288/display.c
index 192580b534cd..ab297a21d195 100644
--- a/src/soc/rockchip/rk3288/display.c
+++ b/src/soc/rockchip/rk3288/display.c
@@ -46,6 +46,7 @@ void rk_display_init(device_t dev, u32 lcdbase,
 	struct soc_rockchip_rk3288_config *conf = dev->chip_info;
 	uint32_t lower = ALIGN_DOWN(lcdbase, MiB);
 	uint32_t upper = ALIGN_UP(lcdbase + fb_size, MiB);
+	enum vop_modes detected_mode = VOP_MODE_UNKNOWN;
 
 	printk(BIOS_SPEW, "LCD framebuffer @%p\n", (void *)(lcdbase));
 	memset((void *)lcdbase, 0, fb_size);	/* clear the framebuffer */
@@ -53,26 +54,41 @@ void rk_display_init(device_t dev, u32 lcdbase,
 	mmu_config_range(lower / MiB, (upper - lower) / MiB, DCACHE_OFF);
 
 	switch (conf->vop_mode) {
-	case HDMI_MODE:
+	case VOP_MODE_AUTO_DETECT:
+		/* try EDP first, then HDMI */
+	case VOP_MODE_EDP:
+		printk(BIOS_DEBUG, "Attempting to setup EDP display.\n");
+		rkclk_configure_edp();
+		rkclk_configure_vop_aclk(conf->vop_id, 192 * MHz);
+		rk_edp_init(conf->vop_id);
+
+		if (rk_edp_get_edid(&edid) == 0) {
+			detected_mode = VOP_MODE_EDP;
+			break;
+		} else {
+			printk(BIOS_WARNING, "Cannot get EDID from EDP.\n");
+			if (conf->vop_mode == VOP_MODE_EDP)
+				return;
+		}
+		/* fall thru */
+	case VOP_MODE_HDMI:
+		printk(BIOS_DEBUG, "Attempting to setup HDMI display.\n");
 		rkclk_configure_hdmi();
 		rkclk_configure_vop_aclk(conf->vop_id, 384 * MHz);
 		rk_hdmi_init(conf->vop_id);
-		if (rk_hdmi_get_edid(&edid)) {
-			printk(BIOS_WARNING, "can not get edid\n");
-			return;
-		}
-		break;
 
-	case EDP_MODE:
-	default:
-		rkclk_configure_edp();
-		rkclk_configure_vop_aclk(conf->vop_id, 192 * MHz);
-		rk_edp_init(conf->vop_id);
-		if (rk_edp_get_edid(&edid)) {
-			printk(BIOS_WARNING, "can not get edid\n");
-			return;
+		if (rk_hdmi_get_edid(&edid) == 0) {
+			detected_mode = VOP_MODE_HDMI;
+			break;
+		} else {
+			printk(BIOS_WARNING, "Cannot get EDID from HDMI.\n");
+			if (conf->vop_mode == VOP_MODE_HDMI)
+				return;
 		}
-		break;
+		/* fall thru */
+	default:
+		printk(BIOS_WARNING, "Cannot read any edid info, aborting.\n");
+		return;
 	}
 
 	if (rkclk_configure_vop_dclk(conf->vop_id, edid.pixel_clock * KHz)) {
@@ -84,12 +100,12 @@ void rk_display_init(device_t dev, u32 lcdbase,
 	edid.bytes_per_line = edid.ha * conf->framebuffer_bits_per_pixel / 8;
 	edid.x_resolution = edid.ha;
 	edid.y_resolution = edid.va;
-	rkvop_mode_set(conf->vop_id, &edid, conf->vop_mode);
+	rkvop_mode_set(conf->vop_id, &edid, detected_mode);
 
 	rkvop_enable(conf->vop_id, lcdbase, &edid);
 
-	switch (conf->vop_mode) {
-	case HDMI_MODE:
+	switch (detected_mode) {
+	case VOP_MODE_HDMI:
 		if (rk_hdmi_enable(&edid)) {
 			printk(BIOS_WARNING, "hdmi enable err\n");
 			return;
@@ -103,7 +119,7 @@ void rk_display_init(device_t dev, u32 lcdbase,
 		mdelay(2000);
 		break;
 
-	case EDP_MODE:
+	case VOP_MODE_EDP:
 	default:
 		if (rk_edp_enable()) {
 			printk(BIOS_WARNING, "edp enable err\n");
diff --git a/src/soc/rockchip/rk3288/include/soc/vop.h b/src/soc/rockchip/rk3288/include/soc/vop.h
index 6cb883a63566..2690726b0799 100644
--- a/src/soc/rockchip/rk3288/include/soc/vop.h
+++ b/src/soc/rockchip/rk3288/include/soc/vop.h
@@ -100,9 +100,15 @@ enum {
 	LB_RGB_1280X8 = 0x5
 };
 
-enum {
-	EDP_MODE,
-	HDMI_MODE,
+enum vop_modes {
+	/* EDP == 0 is used for early RK3288 products and is the most likely
+	 * use case, so keep it as the default. Other desired modes should
+	 * be set explicitly in the board's devicetree.cb.
+	 */
+	VOP_MODE_EDP = 0,
+	VOP_MODE_HDMI,
+	VOP_MODE_AUTO_DETECT,
+	VOP_MODE_UNKNOWN,
 };
 
 /* VOP_VERSION_INFO */
diff --git a/src/soc/rockchip/rk3288/vop.c b/src/soc/rockchip/rk3288/vop.c
index 03338e85a4c0..8c693214770c 100644
--- a/src/soc/rockchip/rk3288/vop.c
+++ b/src/soc/rockchip/rk3288/vop.c
@@ -110,12 +110,12 @@ void rkvop_mode_set(u32 vop_id, const struct edid *edid, u32 mode)
 
 	switch (mode) {
 
-	case HDMI_MODE:
+	case VOP_MODE_HDMI:
 		clrsetbits_le32(&preg->sys_ctrl,
 				M_ALL_OUT_EN, V_HDMI_OUT_EN(1));
 		break;
 
-	case EDP_MODE:
+	case VOP_MODE_EDP:
 	default:
 		clrsetbits_le32(&preg->sys_ctrl,
 				M_ALL_OUT_EN, V_EDP_OUT_EN(1));