FUI: add intel_dp driver derived from kernel functions

These functions are not all used yet, but do compile and are partially used
in the FUI testing.

They were extracted from the 3.4 kernel using coccinnelle filters. The .c files
are only compiled in if CONFIG_INTEL_DP is set.

Change-Id: Id95622a75aa02b496c9ea4717cb143394a8332e3
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/60245
Commit-Queue: Ronald G. Minnich <rminnich@chromium.org>
Tested-by: Ronald G. Minnich <rminnich@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@google.com>
Reviewed-on: http://review.coreboot.org/4329
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

6 files changed, 2290 insertions, 0 deletions

diff --git a/src/drivers/intel/gma/Kconfig b/src/drivers/intel/gma/Kconfig
new file mode 100644
index 0000000000..1a4212bd49
--- /dev/null
+++ b/src/drivers/intel/gma/Kconfig
@@ -0,0 +1,24 @@
+##
+## This file is part of the coreboot project.
+##
+## Copyright 2013 Google Inc.
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; version 2 of the License.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+##
+
+config INTEL_DP
+	bool
+	default n
+	help
+	  helper functions for intel display port operations
diff --git a/src/drivers/intel/gma/Makefile.inc b/src/drivers/intel/gma/Makefile.inc
new file mode 100644
index 0000000000..c90daa4f37
--- /dev/null
+++ b/src/drivers/intel/gma/Makefile.inc
@@ -0,0 +1,21 @@
+##
+## This file is part of the coreboot project.
+##
+## Copyright (C) 2013 Google Inc.
+##
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; version 2 of the License.
+##
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+##
+## You should have received a copy of the GNU General Public License
+## along with this program; if not, write to the Free Software
+## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+##
+
+ramstage-$(CONFIG_INTEL_DP) += intel_dp.c drm_dp_helper.c
+
diff --git a/src/drivers/intel/gma/drm_dp_helper.c b/src/drivers/intel/gma/drm_dp_helper.c
new file mode 100644
index 0000000000..66072263f4
--- /dev/null
+++ b/src/drivers/intel/gma/drm_dp_helper.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright 2013 Google Inc.
+ * Copyright © 2009 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <console/console.h>
+#include <stdint.h>
+#include <delay.h>
+#include <drivers/intel/gma/i915.h>
+#include <string.h>
+
+#include <edid.h>
+
+/* reduced a lot for coreboot. */
+/**
+ * DOC: dp helpers
+ *
+ * These functions contain some common logic and helpers at various
+ * abstraction levels to deal with Display Port sink devices and
+ * related things like DP aux channel transfers, EDID reading over DP
+ * aux channels, decoding certain DPCD blocks, ...
+ */
+
+
+/* Helpers for DP link training */
+static u8 dp_link_status(u8 link_status[DP_LINK_STATUS_SIZE], int r)
+{
+	printk(BIOS_SPEW, "%s: %d, %d, %d\n", __func__,
+	       r, r - DP_LANE0_1_STATUS,
+	       link_status[r - DP_LANE0_1_STATUS]);
+	return link_status[r - DP_LANE0_1_STATUS];
+}
+
+static u8 dp_get_lane_status(u8 link_status[DP_LINK_STATUS_SIZE],
+			     int lane)
+{
+	int i = DP_LANE0_1_STATUS + (lane >> 1);
+	int s = (lane & 1) * 4;
+	u8 l = dp_link_status(link_status, i);
+	return (l >> s) & 0xf;
+}
+
+int drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+			  int lane_count)
+{
+	u8 lane_align;
+	u8 lane_status;
+	int lane;
+
+	lane_align = dp_link_status(link_status,
+				    DP_LANE_ALIGN_STATUS_UPDATED);
+	if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
+		return 0;
+	for (lane = 0; lane < lane_count; lane++) {
+		lane_status = dp_get_lane_status(link_status, lane);
+		if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS)
+			return 0;
+	}
+	return 1;
+}
+
+int drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+			      int lane_count)
+{
+	int lane;
+	u8 lane_status;
+
+	for (lane = 0; lane < lane_count; lane++) {
+		lane_status = dp_get_lane_status(link_status, lane);
+		if ((lane_status & DP_LANE_CR_DONE) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
+				     int lane)
+{
+	int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
+	int s = ((lane & 1) ?
+		 DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
+		 DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
+	u8 l = dp_link_status(link_status, i);
+
+	printk(BIOS_SPEW, "%s: i %d s %d l %d return %d\n",
+	       __func__, i, s, l,
+	       ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT);
+	return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
+}
+
+u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
+					  int lane)
+{
+	int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
+	int s = ((lane & 1) ?
+		 DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
+		 DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
+	u8 l = dp_link_status(link_status, i);
+
+	return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
+}
diff --git a/src/drivers/intel/gma/drm_dp_helper.h b/src/drivers/intel/gma/drm_dp_helper.h
new file mode 100644
index 0000000000..f2e06c33f3
--- /dev/null
+++ b/src/drivers/intel/gma/drm_dp_helper.h
@@ -0,0 +1,239 @@
+/*
+ * Copyright 2013 Google Inc.
+ * Copyright © 2008 Keith Packard
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef _DRM_DP_HELPER_H_
+#define _DRM_DP_HELPER_H_
+
+/* From the VESA DisplayPort spec */
+
+#define AUX_NATIVE_WRITE	0x8
+#define AUX_NATIVE_READ		0x9
+#define AUX_I2C_WRITE		0x0
+#define AUX_I2C_READ		0x1
+#define AUX_I2C_STATUS		0x2
+#define AUX_I2C_MOT		0x4
+
+#define AUX_NATIVE_REPLY_ACK	(0x0 << 4)
+#define AUX_NATIVE_REPLY_NACK	(0x1 << 4)
+#define AUX_NATIVE_REPLY_DEFER	(0x2 << 4)
+#define AUX_NATIVE_REPLY_MASK	(0x3 << 4)
+
+#define AUX_I2C_REPLY_ACK	(0x0 << 6)
+#define AUX_I2C_REPLY_NACK	(0x1 << 6)
+#define AUX_I2C_REPLY_DEFER	(0x2 << 6)
+#define AUX_I2C_REPLY_MASK	(0x3 << 6)
+
+/* AUX CH addresses */
+/* DPCD */
+#define DP_DPCD_REV                         0x000
+
+#define DP_MAX_LINK_RATE                    0x001
+
+#define DP_MAX_LANE_COUNT                   0x002
+# define DP_MAX_LANE_COUNT_MASK		    0x1f
+# define DP_TPS3_SUPPORTED		    (1 << 6)
+# define DP_ENHANCED_FRAME_CAP		    (1 << 7)
+
+#define DP_MAX_DOWNSPREAD                   0x003
+# define DP_NO_AUX_HANDSHAKE_LINK_TRAINING  (1 << 6)
+
+#define DP_NORP                             0x004
+
+#define DP_DOWNSTREAMPORT_PRESENT           0x005
+# define DP_DWN_STRM_PORT_PRESENT           (1 << 0)
+# define DP_DWN_STRM_PORT_TYPE_MASK         0x06
+/* 00b = DisplayPort */
+/* 01b = Analog */
+/* 10b = TMDS or HDMI */
+/* 11b = Other */
+# define DP_FORMAT_CONVERSION               (1 << 3)
+
+#define DP_MAIN_LINK_CHANNEL_CODING         0x006
+
+#define DP_EDP_CONFIGURATION_CAP            0x00d
+#define DP_TRAINING_AUX_RD_INTERVAL         0x00e
+
+#define DP_PSR_SUPPORT                      0x070
+# define DP_PSR_IS_SUPPORTED                1
+#define DP_PSR_CAPS                         0x071
+# define DP_PSR_NO_TRAIN_ON_EXIT            1
+# define DP_PSR_SETUP_TIME_330              (0 << 1)
+# define DP_PSR_SETUP_TIME_275              (1 << 1)
+# define DP_PSR_SETUP_TIME_220              (2 << 1)
+# define DP_PSR_SETUP_TIME_165              (3 << 1)
+# define DP_PSR_SETUP_TIME_110              (4 << 1)
+# define DP_PSR_SETUP_TIME_55               (5 << 1)
+# define DP_PSR_SETUP_TIME_0                (6 << 1)
+# define DP_PSR_SETUP_TIME_MASK             (7 << 1)
+# define DP_PSR_SETUP_TIME_SHIFT            1
+
+/* link configuration */
+#define	DP_LINK_BW_SET		            0x100
+# define DP_LINK_BW_1_62		    0x06
+# define DP_LINK_BW_2_7			    0x0a
+# define DP_LINK_BW_5_4			    0x14
+
+#define DP_LANE_COUNT_SET	            0x101
+# define DP_LANE_COUNT_MASK		    0x0f
+# define DP_LANE_COUNT_ENHANCED_FRAME_EN    (1 << 7)
+
+#define DP_TRAINING_PATTERN_SET	            0x102
+# define DP_TRAINING_PATTERN_DISABLE	    0
+# define DP_TRAINING_PATTERN_1		    1
+# define DP_TRAINING_PATTERN_2		    2
+# define DP_TRAINING_PATTERN_3		    3
+# define DP_TRAINING_PATTERN_MASK	    0x3
+
+# define DP_LINK_QUAL_PATTERN_DISABLE	    (0 << 2)
+# define DP_LINK_QUAL_PATTERN_D10_2	    (1 << 2)
+# define DP_LINK_QUAL_PATTERN_ERROR_RATE    (2 << 2)
+# define DP_LINK_QUAL_PATTERN_PRBS7	    (3 << 2)
+# define DP_LINK_QUAL_PATTERN_MASK	    (3 << 2)
+
+# define DP_RECOVERED_CLOCK_OUT_EN	    (1 << 4)
+# define DP_LINK_SCRAMBLING_DISABLE	    (1 << 5)
+
+# define DP_SYMBOL_ERROR_COUNT_BOTH	    (0 << 6)
+# define DP_SYMBOL_ERROR_COUNT_DISPARITY    (1 << 6)
+# define DP_SYMBOL_ERROR_COUNT_SYMBOL	    (2 << 6)
+# define DP_SYMBOL_ERROR_COUNT_MASK	    (3 << 6)
+
+#define DP_TRAINING_LANE0_SET		    0x103
+#define DP_TRAINING_LANE1_SET		    0x104
+#define DP_TRAINING_LANE2_SET		    0x105
+#define DP_TRAINING_LANE3_SET		    0x106
+
+# define DP_TRAIN_VOLTAGE_SWING_MASK	    0x3
+# define DP_TRAIN_VOLTAGE_SWING_SHIFT	    0
+# define DP_TRAIN_MAX_SWING_REACHED	    (1 << 2)
+# define DP_TRAIN_VOLTAGE_SWING_400	    (0 << 0)
+# define DP_TRAIN_VOLTAGE_SWING_600	    (1 << 0)
+# define DP_TRAIN_VOLTAGE_SWING_800	    (2 << 0)
+# define DP_TRAIN_VOLTAGE_SWING_1200	    (3 << 0)
+
+# define DP_TRAIN_PRE_EMPHASIS_MASK	    (3 << 3)
+# define DP_TRAIN_PRE_EMPHASIS_0	    (0 << 3)
+# define DP_TRAIN_PRE_EMPHASIS_3_5	    (1 << 3)
+# define DP_TRAIN_PRE_EMPHASIS_6	    (2 << 3)
+# define DP_TRAIN_PRE_EMPHASIS_9_5	    (3 << 3)
+
+# define DP_TRAIN_PRE_EMPHASIS_SHIFT	    3
+# define DP_TRAIN_MAX_PRE_EMPHASIS_REACHED  (1 << 5)
+
+#define DP_DOWNSPREAD_CTRL		    0x107
+# define DP_SPREAD_AMP_0_5		    (1 << 4)
+
+#define DP_MAIN_LINK_CHANNEL_CODING_SET	    0x108
+# define DP_SET_ANSI_8B10B		    (1 << 0)
+
+#define DP_PSR_EN_CFG			    0x170
+# define DP_PSR_ENABLE			    (1 << 0)
+# define DP_PSR_MAIN_LINK_ACTIVE	    (1 << 1)
+# define DP_PSR_CRC_VERIFICATION	    (1 << 2)
+# define DP_PSR_FRAME_CAPTURE		    (1 << 3)
+
+#define DP_DEVICE_SERVICE_IRQ_VECTOR	    0x201
+# define DP_REMOTE_CONTROL_COMMAND_PENDING  (1 << 0)
+# define DP_AUTOMATED_TEST_REQUEST	    (1 << 1)
+# define DP_CP_IRQ			    (1 << 2)
+# define DP_SINK_SPECIFIC_IRQ		    (1 << 6)
+
+#define DP_EDP_CONFIGURATION_SET            0x10a
+
+#define DP_LANE0_1_STATUS		    0x202
+#define DP_LANE2_3_STATUS		    0x203
+# define DP_LANE_CR_DONE		    (1 << 0)
+# define DP_LANE_CHANNEL_EQ_DONE	    (1 << 1)
+# define DP_LANE_SYMBOL_LOCKED		    (1 << 2)
+
+#define DP_CHANNEL_EQ_BITS (DP_LANE_CR_DONE |		\
+			    DP_LANE_CHANNEL_EQ_DONE |	\
+			    DP_LANE_SYMBOL_LOCKED)
+
+#define DP_LANE_ALIGN_STATUS_UPDATED	    0x204
+
+#define DP_INTERLANE_ALIGN_DONE		    (1 << 0)
+#define DP_DOWNSTREAM_PORT_STATUS_CHANGED   (1 << 6)
+#define DP_LINK_STATUS_UPDATED		    (1 << 7)
+
+#define DP_SINK_STATUS			    0x205
+
+#define DP_RECEIVE_PORT_0_STATUS	    (1 << 0)
+#define DP_RECEIVE_PORT_1_STATUS	    (1 << 1)
+
+#define DP_ADJUST_REQUEST_LANE0_1	    0x206
+#define DP_ADJUST_REQUEST_LANE2_3	    0x207
+# define DP_ADJUST_VOLTAGE_SWING_LANE0_MASK  0x03
+# define DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT 0
+# define DP_ADJUST_PRE_EMPHASIS_LANE0_MASK   0x0c
+# define DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT  2
+# define DP_ADJUST_VOLTAGE_SWING_LANE1_MASK  0x30
+# define DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT 4
+# define DP_ADJUST_PRE_EMPHASIS_LANE1_MASK   0xc0
+# define DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT  6
+
+#define DP_TEST_REQUEST			    0x218
+# define DP_TEST_LINK_TRAINING		    (1 << 0)
+# define DP_TEST_LINK_PATTERN		    (1 << 1)
+# define DP_TEST_LINK_EDID_READ		    (1 << 2)
+# define DP_TEST_LINK_PHY_TEST_PATTERN	    (1 << 3) /* DPCD >= 1.1 */
+
+#define DP_TEST_LINK_RATE		    0x219
+# define DP_LINK_RATE_162		    (0x6)
+# define DP_LINK_RATE_27		    (0xa)
+
+#define DP_TEST_LANE_COUNT		    0x220
+
+#define DP_TEST_PATTERN			    0x221
+
+#define DP_TEST_RESPONSE		    0x260
+# define DP_TEST_ACK			    (1 << 0)
+# define DP_TEST_NAK			    (1 << 1)
+# define DP_TEST_EDID_CHECKSUM_WRITE	    (1 << 2)
+
+#define DP_SET_POWER                        0x600
+# define DP_SET_POWER_D0                    0x1
+# define DP_SET_POWER_D3                    0x2
+
+#define DP_PSR_ERROR_STATUS                 0x2006
+# define DP_PSR_LINK_CRC_ERROR              (1 << 0)
+# define DP_PSR_RFB_STORAGE_ERROR           (1 << 1)
+
+#define DP_PSR_ESI                          0x2007
+# define DP_PSR_CAPS_CHANGE                 (1 << 0)
+
+#define DP_PSR_STATUS                       0x2008
+# define DP_PSR_SINK_INACTIVE               0
+# define DP_PSR_SINK_ACTIVE_SRC_SYNCED      1
+# define DP_PSR_SINK_ACTIVE_RFB             2
+# define DP_PSR_SINK_ACTIVE_SINK_SYNCED     3
+# define DP_PSR_SINK_ACTIVE_RESYNC          4
+# define DP_PSR_SINK_INTERNAL_ERROR         7
+# define DP_PSR_SINK_STATE_MASK             0x07
+
+#define MODE_I2C_START	1
+#define MODE_I2C_WRITE	2
+#define MODE_I2C_READ	4
+#define MODE_I2C_STOP	8
+
+#endif /* _DRM_DP_HELPER_H_ */
diff --git a/src/drivers/intel/gma/i915.h b/src/drivers/intel/gma/i915.h
new file mode 100644
index 0000000000..37570649f9
--- /dev/null
+++ b/src/drivers/intel/gma/i915.h
@@ -0,0 +1,180 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2012 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <drivers/intel/gma/i915_reg.h>
+#include <drivers/intel/gma/drm_dp_helper.h>
+#include <edid.h>
+
+/* port types. We stick with the same defines as the kernel */
+#define INTEL_OUTPUT_UNUSED 0
+#define INTEL_OUTPUT_ANALOG 1
+#define INTEL_OUTPUT_DVO 2
+#define INTEL_OUTPUT_SDVO 3
+#define INTEL_OUTPUT_LVDS 4
+#define INTEL_OUTPUT_TVOUT 5
+#define INTEL_OUTPUT_HDMI 6
+#define INTEL_OUTPUT_DISPLAYPORT 7
+#define INTEL_OUTPUT_EDP 8
+
+/* things that are, strangely, not defined anywhere? */
+#define PCH_PP_UNLOCK	0xabcd0000
+#define WMx_LP_SR_EN	(1<<31)
+#define PRB0_TAIL	0x02030
+#define PRB0_HEAD	0x02034
+#define PRB0_START	0x02038
+#define PRB0_CTL	0x0203c
+
+/* debug enums. These are for printks that, due to their place in the
+ * middle of graphics device IO, might change timing.  Use with care
+ * or not at all.
+ */
+enum {
+	vio = 2, /* dump every IO */
+	vspin = 4, /* print # of times we spun on a register value */
+};
+
+/* The mainboard must provide these functions. */
+unsigned long io_i915_read32(unsigned long addr);
+void io_i915_write32(unsigned long val, unsigned long addr);
+
+/*
+ * To communicate to and control the extracted-from-kernel code,
+ * we need this struct. It has a counterpart in the ARM code, so
+ * there is a precedent.
+ */
+
+#define DP_RECEIVER_CAP_SIZE	0xf
+#define DP_LINK_STATUS_SIZE	6
+#define DP_LINK_CHECK_TIMEOUT	(10 * 1000)
+
+#define DP_LINK_CONFIGURATION_SIZE	9
+
+struct intel_dp {
+	int gen; // 6 for link, 7 for wtm2
+	int has_pch_split; // 1 for link and wtm2
+	int has_pch_cpt; // 1 for everything we know about.
+	int is_haswell;
+	/* output register offset in MMIO space. Usually DP_A */
+	u32 output_reg;
+	/* The initial value of the DP register.
+	 * Mainboards can set this to a non-zero
+	 * value in the case that there are undetectable
+	 * but essential parameters.
+	 */
+	u32 DP;
+	uint8_t  link_configuration[DP_LINK_CONFIGURATION_SIZE];
+	u32 color_range;
+	/* these paramaters are determined after reading the DPCD */
+	int dpms_mode;
+	uint8_t link_bw;
+	uint8_t lane_count;
+	/* This data is read from the panel via the AUX channel.*/
+	uint8_t dpcd[DP_RECEIVER_CAP_SIZE];
+	int type;
+	int edp;
+	int is_pch_edp;
+	/* state related to training. */
+	uint8_t	train_set[4];
+	/* Determined from EDID or coreboot hard-sets. */
+	int panel_power_up_delay;
+	int panel_power_down_delay;
+	int panel_power_cycle_delay;
+	int backlight_on_delay;
+	int backlight_off_delay;
+	int want_panel_vdd;
+	u32 clock;
+	int port;
+	int pipe;
+	int bpp;
+	/* i2c on aux is ... interesting.
+	 * Before you do an i2c cycle, you need to set the address.
+	 * This requires we remember it from one moment to the next.
+	 * Remember it here.
+	 */
+	u16 address;
+	/* timing parameters for aux channel IO. They used to compute these on
+	 * each and every entry to the functions, which is kind of stupid, and it had
+	 * errors anyway.
+	 * note: you can get these from watching YABEL output. E.g.:
+	 * you see an outb of 0x802300e1 to 64010. the 3 is the precharge
+	 * and the e1 is the clock divider.
+	 */
+	u32 aux_clock_divider;
+	u32 precharge;
+	/* EDID, raw and processed */
+	u8 rawedid[256];
+	int edidlen;
+	struct edid edid;
+	/* computed values needed for "i915" registers */
+	int bytes_per_pixel;
+	u32 htotal;
+	u32 hblank;
+	u32 hsync;
+	u32 vtotal;
+	u32 vblank;
+	u32 vsync;
+	u32 pfa_sz;
+	u32 pfa_pos;
+	u32 pfa_ctl;
+	u32 pipesrc;
+	u32 stride;
+};
+
+/* we may yet need these. */
+void intel_dp_mode_set(struct intel_dp *intel_dp);
+void intel_dp_start_link_train(struct intel_dp *intel_dp);
+void intel_dp_complete_link_train(struct intel_dp *intel_dp);
+void intel_dp_link_down(struct intel_dp *intel_dp);
+
+int intel_dp_i2c_init(struct intel_dp *intel_dp);
+int intel_dp_i2c_aux_ch(struct intel_dp *intel_dp,
+			int mode, uint8_t write_byte, uint8_t *read_byte);
+void
+intel_dp_dpms(struct intel_dp *intel_dp, int mode);
+
+int intel_dp_get_dpcd(struct intel_dp *intel_dp);
+struct edid *intel_dp_get_edid(struct intel_dp *intel_dp);
+
+void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
+void ironlake_edp_pll_on(void);
+void ironlake_edp_panel_vdd_on(struct intel_dp *intel_dp);
+void ironlake_edp_panel_vdd_off(struct intel_dp *intel_dp, int sync);
+int intel_dp_get_max_downspread(struct intel_dp *intel_dp, u8 *max_downspread);
+void ironlake_edp_panel_on(struct intel_dp *intel_dp);
+void ironlake_edp_backlight_on(struct intel_dp *intel_dp);
+/* needed only on haswell. */
+void intel_prepare_ddi_buffers(int port, int use_fdi_mode);
+void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp, int port);
+int intel_dp_aux_ch(struct intel_dp *intel_dp,
+		    uint8_t *send, int send_bytes,
+		    uint8_t *recv, int recv_size);
+void unpack_aux(u32 src, uint8_t *dst, int dst_bytes);
+
+
+/* drm_dp_helper.c */
+int drm_dp_channel_eq_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+			 int lane_count);
+int drm_dp_clock_recovery_ok(u8 link_status[DP_LINK_STATUS_SIZE],
+			     int lane_count);
+u8 drm_dp_get_adjust_request_voltage(u8 link_status[DP_LINK_STATUS_SIZE],
+				     int lane);
+u8 drm_dp_get_adjust_request_pre_emphasis(u8 link_status[DP_LINK_STATUS_SIZE],
+					  int lane);
+
+
diff --git a/src/drivers/intel/gma/intel_dp.c b/src/drivers/intel/gma/intel_dp.c
new file mode 100644
index 0000000000..4b5f7c49c1
--- /dev/null
+++ b/src/drivers/intel/gma/intel_dp.c
@@ -0,0 +1,1707 @@
+/*
+ * Copyright 2013 Google Inc.
+ * Copyright © 2008 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Keith Packard <keithp@keithp.com>
+ *
+ */
+
+/* This code was created by the coccinnelle filters in the i915tool,
+ * with some final hand filtering.
+ */
+
+#include <console/console.h>
+#include <stdint.h>
+#include <delay.h>
+#include <drivers/intel/gma/i915.h>
+#include <string.h>
+
+/**
+ * is_edp - is the given port attached to an eDP panel (either CPU or PCH)
+ * @intel_dp: DP struct
+ *
+ * If a CPU or PCH DP output is attached to an eDP panel, this function
+ * will return 1, and 0 otherwise.
+ */
+static int is_edp(struct intel_dp *intel_dp)
+{
+	return intel_dp->type == INTEL_OUTPUT_EDP;
+}
+
+/**
+ * is_pch_edp - is the port on the PCH and attached to an eDP panel?
+ * @intel_dp: DP struct
+ *
+ * Returns 1 if the given DP struct corresponds to a PCH DP port attached
+ * to an eDP panel, 0 otherwise.  Helpful for determining whether we
+ * may need FDI resources for a given DP output or not.
+ */
+static int is_pch_edp(struct intel_dp *intel_dp)
+{
+	return intel_dp->is_pch_edp;
+}
+
+/**
+ * is_cpu_edp - is the port on the CPU and attached to an eDP panel?
+ * @intel_dp: DP struct
+ *
+ * Returns 1 if the given DP struct corresponds to a CPU eDP port.
+ */
+static int is_cpu_edp(struct intel_dp *intel_dp)
+{
+	return is_edp(intel_dp) && !is_pch_edp(intel_dp);
+}
+
+static uint32_t
+pack_aux(uint8_t *src, int src_bytes)
+{
+	int	i;
+	uint32_t v = 0;
+
+	if (src_bytes > 4)
+		src_bytes = 4;
+	for (i = 0; i < src_bytes; i++)
+		v |= ((uint32_t) src[i]) << ((3-i) * 8);
+	return v;
+}
+
+void
+unpack_aux(uint32_t src, uint8_t *dst, int dst_bytes)
+{
+	int i;
+	if (dst_bytes > 4)
+		dst_bytes = 4;
+	for (i = 0; i < dst_bytes; i++)
+		dst[i] = src >> ((3-i) * 8);
+}
+
+static int ironlake_edp_have_panel_power(struct intel_dp *intel_dp)
+{
+
+	return (io_i915_read32(PCH_PP_STATUS) & PP_ON) != 0;
+}
+
+static int ironlake_edp_have_panel_vdd(struct intel_dp *intel_dp)
+{
+	return (io_i915_read32(PCH_PP_CONTROL) & EDP_FORCE_VDD) != 0;
+}
+
+int
+intel_dp_aux_ch(struct intel_dp *intel_dp,
+		uint8_t *send, int send_bytes,
+		uint8_t *recv, int recv_size)
+{
+	uint32_t output_reg = intel_dp->output_reg;
+	uint32_t ch_ctl = output_reg + 0x10;
+	uint32_t ch_data = ch_ctl + 4;
+	int i;
+	int recv_bytes;
+	uint32_t status;
+	int try;
+
+	/* Try to wait for any previous AUX channel activity */
+	for (try = 0; try < 3; try++) {
+		status = io_i915_read32(ch_ctl);
+		if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
+			break;
+		mdelay(1);
+	}
+
+	if (try == 3) {
+		if (1) {
+			status = io_i915_read32(ch_ctl);
+			printk(BIOS_ERR,
+			       "dp_aux_ch not started status 0x%08x\n",
+			       status);
+		}
+		return -1;
+	}
+
+	/* Must try at least 3 times according to DP spec */
+	for (try = 0; try < 5; try++) {
+		/* Load the send data into the aux channel data registers */
+		for (i = 0; i < send_bytes; i += 4){
+			u32 val, addr;
+			val = pack_aux(send + i, send_bytes - i);
+			addr = ch_data + i;
+			io_i915_write32(val, addr);
+		}
+
+		/* Send the command and wait for it to complete */
+		io_i915_write32(DP_AUX_CH_CTL_SEND_BUSY |
+				DP_AUX_CH_CTL_TIME_OUT_400us |
+				(send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
+				(intel_dp->precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
+				(intel_dp->aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT) |
+				DP_AUX_CH_CTL_DONE |
+				DP_AUX_CH_CTL_TIME_OUT_ERROR |
+				DP_AUX_CH_CTL_RECEIVE_ERROR, ch_ctl);
+		for (;;) {
+			status = io_i915_read32(ch_ctl);
+			if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
+				break;
+			udelay(100);
+		}
+
+		/* Clear done status and any errors */
+		io_i915_write32(status |
+				DP_AUX_CH_CTL_DONE |
+				DP_AUX_CH_CTL_TIME_OUT_ERROR |
+				DP_AUX_CH_CTL_RECEIVE_ERROR, ch_ctl);
+
+		if (status & (DP_AUX_CH_CTL_TIME_OUT_ERROR |
+			      DP_AUX_CH_CTL_RECEIVE_ERROR))
+			continue;
+		if (status & DP_AUX_CH_CTL_DONE)
+			break;
+	}
+
+	if ((status & DP_AUX_CH_CTL_DONE) == 0) {
+		printk(BIOS_ERR, "dp_aux_ch not done status 0x%08x\n", status);
+		return -1;
+	}
+
+	/* Check for timeout or receive error.
+	 * Timeouts occur when the sink is not connected
+	 */
+	if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
+		printk(BIOS_ERR,
+		       "dp_aux_ch receive error status 0x%08x\n", status);
+		return -1;
+	}
+
+	/* Timeouts occur when the device isn't connected, so they're
+	 * "normal" -- don't fill the kernel log with these */
+	if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
+		printk(BIOS_ERR, "dp_aux_ch timeout status 0x%08x\n", status);
+		return -1;
+	}
+
+	/* Unload any bytes sent back from the other side */
+	recv_bytes = ((status & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >>
+		      DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);
+	if (recv_bytes > recv_size)
+		recv_bytes = recv_size;
+
+	for (i = 0; i < recv_bytes; i += 4)
+		unpack_aux(io_i915_read32(ch_data + i),
+			   recv + i, recv_bytes - i);
+
+	return recv_bytes;
+}
+
+/* Write data to the aux channel in native mode */
+static int
+intel_dp_aux_native_write(struct intel_dp *intel_dp,
+			  uint16_t address, uint8_t *send, int send_bytes)
+{
+	int ret;
+	uint8_t	msg[20];
+	int msg_bytes;
+	uint8_t	ack;
+
+	if (send_bytes > 16)
+		return -1;
+	msg[0] = AUX_NATIVE_WRITE << 4;
+	msg[1] = address >> 8;
+	msg[2] = address & 0xff;
+	msg[3] = send_bytes - 1;
+	memcpy(&msg[4], send, send_bytes);
+	msg_bytes = send_bytes + 4;
+	for (;;) {
+		ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes, &ack, 1);
+		if (ret < 0)
+			return ret;
+		if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
+			break;
+		else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
+			udelay(100);
+		else
+			return -1;
+	}
+	return send_bytes;
+}
+
+/* Write a single byte to the aux channel in native mode */
+static int
+intel_dp_aux_native_write_1(struct intel_dp *intel_dp,
+			    uint16_t address, uint8_t byte)
+{
+	return intel_dp_aux_native_write(intel_dp, address, &byte, 1);
+}
+
+/* read bytes from a native aux channel */
+static int
+intel_dp_aux_native_read(struct intel_dp *intel_dp,
+			 uint16_t address, uint8_t *recv, int recv_bytes)
+{
+	uint8_t msg[4];
+	int msg_bytes;
+	uint8_t reply[20];
+	int reply_bytes;
+	uint8_t ack;
+	int ret;
+
+	msg[0] = AUX_NATIVE_READ << 4;
+	msg[1] = address >> 8;
+	msg[2] = address & 0xff;
+	msg[3] = recv_bytes - 1;
+
+	msg_bytes = 4;
+	reply_bytes = recv_bytes + 1;
+
+	for (;;) {
+		ret = intel_dp_aux_ch(intel_dp, msg, msg_bytes,
+				      reply, reply_bytes);
+		if (ret == 0)
+			return -1;
+		if (ret < 0)
+			return ret;
+		ack = reply[0];
+		if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) {
+			memcpy(recv, reply + 1, ret - 1);
+			return ret - 1;
+		}
+		else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
+			udelay(100);
+		else
+			return -1;
+	}
+}
+
+int
+intel_dp_i2c_aux_ch(struct intel_dp *intel_dp,
+		    int mode, uint8_t write_byte, uint8_t *read_byte)
+{
+	uint8_t msg[5];
+	uint8_t reply[2];
+	unsigned retry;
+	int msg_bytes;
+	int reply_bytes;
+	int ret;
+
+	/* Set up the command byte */
+	if (mode & MODE_I2C_READ)
+		msg[0] = AUX_I2C_READ << 4;
+	else
+		msg[0] = AUX_I2C_WRITE << 4;
+
+	if (!(mode & MODE_I2C_STOP))
+		msg[0] |= AUX_I2C_MOT << 4;
+
+	msg[1] = intel_dp->address >> 8;
+	msg[2] = intel_dp->address;
+
+	switch (mode) {
+	case MODE_I2C_WRITE:
+		msg[3] = 0;
+		msg[4] = write_byte;
+		msg_bytes = 5;
+		reply_bytes = 1;
+		break;
+	case MODE_I2C_READ:
+		msg[3] = 0;
+		msg_bytes = 4;
+		reply_bytes = 2;
+		break;
+	default:
+		msg_bytes = 3;
+		reply_bytes = 1;
+		break;
+	}
+
+	for (retry = 0; retry < 5; retry++) {
+		ret = intel_dp_aux_ch(intel_dp,
+				      msg, msg_bytes,
+				      reply, reply_bytes);
+		if (ret < 0) {
+			printk(BIOS_ERR, "aux_ch failed %d\n", ret);
+			return ret;
+		}
+
+		switch (reply[0] & AUX_NATIVE_REPLY_MASK) {
+		case AUX_NATIVE_REPLY_ACK:
+			/* I2C-over-AUX Reply field is only valid
+			 * when paired with AUX ACK.
+			 */
+			break;
+		case AUX_NATIVE_REPLY_NACK:
+			printk(BIOS_ERR, "aux_ch native nack\n");
+			return -1;
+		case AUX_NATIVE_REPLY_DEFER:
+			udelay(100);
+			continue;
+		default:
+			printk(BIOS_ERR, "aux_ch invalid native reply 0x%02x\n",
+			       reply[0]);
+			return -1;
+		}
+
+		switch (reply[0] & AUX_I2C_REPLY_MASK) {
+		case AUX_I2C_REPLY_ACK:
+			if (mode == MODE_I2C_READ) {
+				*read_byte = reply[1];
+			}
+			return reply_bytes - 1;
+		case AUX_I2C_REPLY_NACK:
+			printk(BIOS_ERR, "aux_i2c nack\n");
+			return -1;
+		case AUX_I2C_REPLY_DEFER:
+			printk(BIOS_ERR, "aux_i2c defer\n");
+			udelay(100);
+			break;
+		default:
+			printk(BIOS_ERR,
+			       "aux_i2c invalid reply 0x%02x\n", reply[0]);
+			return -1;
+		}
+	}
+
+	printk(BIOS_ERR, "too many retries, giving up\n");
+	return -1;
+}
+
+int
+intel_dp_i2c_init(struct intel_dp *intel_dp)
+{
+	int	ret = 0;
+
+	/* not clear what we need to do here, if anything.
+	 * this function was more about setting up the kernel.
+	 * it's a handy placeholder, so we leave it in for now.
+	 */
+	return ret;
+}
+
+struct intel_dp_m_n {
+	uint32_t	tu;
+	uint32_t	gmch_m;
+	uint32_t	gmch_n;
+	uint32_t	link_m;
+	uint32_t	link_n;
+};
+
+static void
+intel_reduce_ratio(uint32_t *num, uint32_t *den)
+{
+	while (*num > 0xffffff || *den > 0xffffff) {
+		*num >>= 1;
+		*den >>= 1;
+	}
+}
+
+static void
+intel_dp_compute_m_n(int bpp,
+		     int nlanes,
+		     int pixel_clock,
+		     int link_clock,
+		     struct intel_dp_m_n *m_n)
+{
+	m_n->tu = 64;
+	m_n->gmch_m = (pixel_clock * bpp) >> 3;
+	m_n->gmch_n = link_clock * nlanes;
+	intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
+	m_n->link_m = pixel_clock;
+	m_n->link_n = link_clock;
+	intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
+}
+
+/* not sure. */
+void intel_dp_set_m_n(struct intel_dp *intel_dp);
+
+void
+intel_dp_set_m_n(struct intel_dp *intel_dp)
+{
+	int lane_count;
+	struct intel_dp_m_n m_n;
+	int pipe = intel_dp->pipe;
+
+	lane_count = intel_dp->lane_count;
+
+	/*
+	 * Compute the GMCH and Link ratios. The '3' here is
+	 * the number of bytes_per_pixel post-LUT, which we always
+	 * set up for 8-bits of R/G/B, or 3 bytes total.
+	 */
+	intel_dp_compute_m_n(intel_dp->bpp, lane_count,
+			     intel_dp->clock, intel_dp->clock, &m_n);
+
+	{
+		io_i915_write32((
+					(m_n.tu - 1) <<
+					PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
+				m_n.gmch_m, TRANSDATA_M1(pipe));
+		io_i915_write32(m_n.gmch_n, TRANSDATA_N1(pipe));
+		io_i915_write32(m_n.link_m, TRANSDPLINK_M1(pipe));
+		io_i915_write32(m_n.link_n, TRANSDPLINK_N1(pipe));
+	}
+}
+
+static void ironlake_edp_pll_off(void);
+
+void
+intel_dp_mode_set(struct intel_dp *intel_dp)
+{
+	/* Turn on the eDP PLL if needed */
+	if (is_edp(intel_dp)) {
+		if (!is_pch_edp(intel_dp))
+			ironlake_edp_pll_on();
+		else
+			ironlake_edp_pll_off();
+	}
+
+	/*
+	 * There are four kinds of DP registers:
+	 *
+	 * 	IBX PCH
+	 * 	SNB CPU
+	 *	IVB CPU
+	 * 	CPT PCH
+	 *
+	 * IBX PCH and CPU are the same for almost everything,
+	 * except that the CPU DP PLL is configured in this
+	 * register
+	 *
+	 * CPT PCH is quite different, having many bits moved
+	 * to the TRANS_DP_CTL register instead. That
+	 * configuration happens (oddly) in ironlake_pch_enable
+	 */
+
+	/* Preserve the BIOS-computed detected bit. This is
+	 * supposed to be read-only.
+	 */
+	intel_dp->DP = io_i915_read32(intel_dp->output_reg) & DP_DETECTED;
+	printk(BIOS_SPEW, "%s: initial value is %08lx\n", __func__,
+	       (unsigned long)intel_dp->DP);
+	/* | 0 essentially */
+	intel_dp->DP |=  DP_VOLTAGE_0_4 | DP_PRE_EMPHASIS_0;
+
+	/* Handle DP bits in common between all three register formats */
+
+	switch (intel_dp->lane_count) {
+	case 1:
+		intel_dp->DP |= DP_PORT_WIDTH_1;
+		break;
+	case 2:
+		intel_dp->DP |= DP_PORT_WIDTH_2;
+		break;
+	case 4:
+		intel_dp->DP |= DP_PORT_WIDTH_4;
+		break;
+	}
+	memset(intel_dp->link_configuration, 0, DP_LINK_CONFIGURATION_SIZE);
+	intel_dp->link_configuration[0] = intel_dp->link_bw;
+	intel_dp->link_configuration[1] = intel_dp->lane_count;
+	intel_dp->link_configuration[8] = DP_SET_ANSI_8B10B;
+	/*
+	 * Check for DPCD version > 1.1 and enhanced framing support
+	 */
+	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
+	    (intel_dp->dpcd[DP_MAX_LANE_COUNT] & DP_ENHANCED_FRAME_CAP)) {
+		intel_dp->link_configuration[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
+	}
+
+	/* Split out the IBX/CPU vs CPT settings */
+
+	if (is_cpu_edp(intel_dp) && (intel_dp->gen == 7)) {
+		/* what are these? We're not sure.
+		   if (adjusted_mode->flags & DRM_MODE_FLAG_PHSYNC)
+		   intel_dp->DP |= DP_SYNC_HS_HIGH;
+
+		   if (adjusted_mode->flags & DRM_MODE_FLAG_PVSYNC)
+		*/
+		intel_dp->DP |= DP_SYNC_VS_HIGH;
+		/* */
+		intel_dp->DP |= DP_LINK_TRAIN_OFF_CPT;
+
+		if (intel_dp->link_configuration[1] &
+		    DP_LANE_COUNT_ENHANCED_FRAME_EN)
+			intel_dp->DP |= DP_ENHANCED_FRAMING;
+
+		intel_dp->DP |= intel_dp->pipe << 29;
+
+		/* don't miss out required setting for eDP */
+		intel_dp->DP |= DP_PLL_ENABLE;
+		if (intel_dp->clock < 200000)
+			intel_dp->DP |= DP_PLL_FREQ_160MHZ;
+		else
+			intel_dp->DP |= DP_PLL_FREQ_270MHZ;
+	} else if (!intel_dp->has_pch_cpt || is_cpu_edp(intel_dp)) {
+		intel_dp->DP |= intel_dp->color_range;
+		intel_dp->DP |= DP_LINK_TRAIN_OFF;
+
+		if (intel_dp->link_configuration[1] &
+		    DP_LANE_COUNT_ENHANCED_FRAME_EN)
+			intel_dp->DP |= DP_ENHANCED_FRAMING;
+
+		if (intel_dp->pipe == 1)
+			intel_dp->DP |= DP_PIPEB_SELECT;
+
+		if (is_cpu_edp(intel_dp)) {
+			/* don't miss out required setting for eDP */
+			intel_dp->DP |= DP_PLL_ENABLE;
+			if (intel_dp->clock < 200000)
+				intel_dp->DP |= DP_PLL_FREQ_160MHZ;
+			else
+				intel_dp->DP |= DP_PLL_FREQ_270MHZ;
+		}
+	} else {
+		intel_dp->DP |= DP_LINK_TRAIN_OFF_CPT;
+	}
+}
+
+#define IDLE_ON_MASK		(PP_ON | 0 	  | PP_SEQUENCE_MASK | 0                     | PP_SEQUENCE_STATE_MASK)
+#define IDLE_ON_VALUE   	(PP_ON | 0 	  | PP_SEQUENCE_NONE | 0                     | PP_SEQUENCE_STATE_ON_IDLE)
+
+#define IDLE_OFF_MASK		(PP_ON | 0        | PP_SEQUENCE_MASK | 0                     | PP_SEQUENCE_STATE_MASK)
+#define IDLE_OFF_VALUE		(0     | 0        | PP_SEQUENCE_NONE | 0                     | PP_SEQUENCE_STATE_OFF_IDLE)
+
+#define IDLE_CYCLE_MASK		(PP_ON | 0        | PP_SEQUENCE_MASK | PP_CYCLE_DELAY_ACTIVE | PP_SEQUENCE_STATE_MASK)
+#define IDLE_CYCLE_VALUE	(0     | 0        | PP_SEQUENCE_NONE | 0                     | PP_SEQUENCE_STATE_OFF_IDLE)
+
+static void ironlake_wait_panel_status(struct intel_dp *intel_dp,
+				       u32 mask,
+				       u32 value)
+{
+	int i;
+	u32 status;
+	printk(BIOS_ERR, "[000000.0] [drm:%s], ", __func__);
+	printk(BIOS_ERR, "mask %08lx value %08lx status %08lx control %08lx\n",
+	       (unsigned long) mask, (unsigned long) value,
+	       (unsigned long)io_i915_read32(PCH_PP_STATUS),
+	       (unsigned long)io_i915_read32(PCH_PP_CONTROL));
+
+	for(i = 0, status = io_i915_read32(PCH_PP_STATUS); ((status & mask) != value) && (i < 5000);
+	    status = io_i915_read32(PCH_PP_STATUS)){
+		udelay(10);
+	}
+	if (i > 5000){
+		printk(BIOS_ERR,
+		       "Panel status timeout: status %08lx control %08lx\n",
+		       (unsigned long)io_i915_read32(PCH_PP_STATUS),
+		       (unsigned long)io_i915_read32(PCH_PP_CONTROL));
+	}
+}
+
+static void ironlake_wait_panel_on(struct intel_dp *intel_dp)
+{
+	printk(BIOS_ERR, "Wait for panel power on\n");
+	ironlake_wait_panel_status(intel_dp, IDLE_ON_MASK, IDLE_ON_VALUE);
+}
+
+static void ironlake_wait_panel_off(struct intel_dp *intel_dp)
+{
+	printk(BIOS_ERR, "Wait for panel power off time\n");
+	ironlake_wait_panel_status(intel_dp, IDLE_OFF_MASK, IDLE_OFF_VALUE);
+}
+
+static void ironlake_wait_panel_power_cycle(struct intel_dp *intel_dp)
+{
+	printk(BIOS_ERR, "Wait for panel power cycle\n");
+	ironlake_wait_panel_status(intel_dp, IDLE_CYCLE_MASK, IDLE_CYCLE_VALUE);
+}
+
+
+/* Read the current pp_control value, unlocking the register if it
+ * is locked
+ */
+
+static  u32 ironlake_get_pp_control(void)
+{
+	u32	control = io_i915_read32(PCH_PP_CONTROL);
+
+	control &= ~PANEL_UNLOCK_MASK;
+	control |= PANEL_UNLOCK_REGS;
+	return control;
+}
+
+void ironlake_edp_panel_vdd_on(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!is_edp(intel_dp))
+		return;
+	printk(BIOS_ERR, "Turn eDP VDD on\n");
+
+	if (intel_dp->want_panel_vdd) {
+		printk(BIOS_ERR, "eDP VDD already requested on\n");
+	}
+
+	intel_dp->want_panel_vdd = 1;
+
+	if (ironlake_edp_have_panel_vdd(intel_dp)) {
+		printk(BIOS_ERR, "eDP VDD already on\n");
+		return;
+	}
+
+	if (!ironlake_edp_have_panel_power(intel_dp))
+		ironlake_wait_panel_power_cycle(intel_dp);
+
+	pp = ironlake_get_pp_control();
+	pp |= EDP_FORCE_VDD;
+	io_i915_write32(pp, PCH_PP_CONTROL);
+	// remember this if we need it later. Not sure yet.
+	////POSTING_READ(PCH_PP_CONTROL);
+	printk(BIOS_ERR, "PCH_PP_STATUS: 0x%08lx PCH_PP_CONTROL: 0x%08lx\n",
+	       io_i915_read32(PCH_PP_STATUS), io_i915_read32(PCH_PP_CONTROL));
+
+	/*
+	 * If the panel wasn't on, delay before accessing aux channel
+	 */
+	if (!ironlake_edp_have_panel_power(intel_dp)) {
+		printk(BIOS_ERR, "eDP was not running\n");
+		mdelay(intel_dp->panel_power_up_delay);
+	}
+}
+
+static void ironlake_panel_vdd_off_sync(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!intel_dp->want_panel_vdd && ironlake_edp_have_panel_vdd(intel_dp)) {
+		pp = ironlake_get_pp_control();
+		pp &= ~EDP_FORCE_VDD;
+		io_i915_write32(pp, PCH_PP_CONTROL);
+		////POSTING_READ(PCH_PP_CONTROL);
+
+		/* Make sure sequencer is idle before allowing subsequent activity */
+		printk(BIOS_ERR, "PCH_PP_STATUS: 0x%08lx PCH_PP_CONTROL: 0x%08lx\n",
+		       io_i915_read32(PCH_PP_STATUS), io_i915_read32(PCH_PP_CONTROL));
+
+		mdelay(intel_dp->panel_power_down_delay);
+	}
+}
+
+void ironlake_edp_panel_vdd_off(struct intel_dp *intel_dp, int sync)
+{
+	if (!is_edp(intel_dp))
+		return;
+
+	printk(BIOS_ERR, "Turn eDP VDD off %d\n", intel_dp->want_panel_vdd);
+	if (!intel_dp->want_panel_vdd) {
+		printk(BIOS_ERR, "eDP VDD not forced on");
+	}
+
+	intel_dp->want_panel_vdd = 0;
+
+	if (sync)
+		ironlake_panel_vdd_off_sync(intel_dp);
+}
+
+void ironlake_edp_panel_on(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!is_edp(intel_dp))
+		return;
+
+	printk(BIOS_ERR, "Turn eDP power on\n");
+
+	if (ironlake_edp_have_panel_power(intel_dp)) {
+		printk(BIOS_ERR, "eDP power already on\n");
+		return;
+	}
+
+	ironlake_wait_panel_power_cycle(intel_dp);
+
+	pp = ironlake_get_pp_control();
+	if ((intel_dp->gen == 5)) {
+		/* ILK workaround: disable reset around power sequence */
+		pp &= ~PANEL_POWER_RESET;
+		io_i915_write32(pp, PCH_PP_CONTROL);
+		////POSTING_READ(PCH_PP_CONTROL);
+	}
+
+	pp |= POWER_TARGET_ON;
+	if (!(intel_dp->gen == 5))
+		pp |= PANEL_POWER_RESET;
+
+	io_i915_write32(pp, PCH_PP_CONTROL);
+	////POSTING_READ(PCH_PP_CONTROL);
+
+	ironlake_wait_panel_on(intel_dp);
+
+	if ((intel_dp->gen == 5)) {
+		pp |= PANEL_POWER_RESET; /* restore panel reset bit */
+		io_i915_write32(pp, PCH_PP_CONTROL);
+		////POSTING_READ(PCH_PP_CONTROL);
+	}
+}
+
+static void ironlake_edp_panel_off(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!is_edp(intel_dp))
+		return;
+
+	printk(BIOS_ERR, "Turn eDP power off\n");
+
+	if (intel_dp->want_panel_vdd) {
+		printk(BIOS_ERR, "Cannot turn power off while VDD is on\n");
+	}
+
+	pp = ironlake_get_pp_control();
+	pp &= ~(POWER_TARGET_ON | EDP_FORCE_VDD |
+		PANEL_POWER_RESET | EDP_BLC_ENABLE);
+	io_i915_write32(pp, PCH_PP_CONTROL);
+	////POSTING_READ(PCH_PP_CONTROL);
+
+	ironlake_wait_panel_off(intel_dp);
+}
+
+void ironlake_edp_backlight_on(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!is_edp(intel_dp))
+		return;
+
+	/*
+	 * If we enable the backlight right away following a panel power
+	 * on, we may see slight flicker as the panel syncs with the eDP
+	 * link.  So delay a bit to make sure the image is solid before
+	 * allowing it to appear.
+	 */
+	mdelay(intel_dp->backlight_on_delay);
+	pp = ironlake_get_pp_control();
+	pp |= EDP_BLC_ENABLE;
+	io_i915_write32(pp, PCH_PP_CONTROL);
+	////POSTING_READ(PCH_PP_CONTROL);
+}
+
+static void ironlake_edp_backlight_off(struct intel_dp *intel_dp)
+{
+	u32 pp;
+
+	if (!is_edp(intel_dp))
+		return;
+
+	pp = ironlake_get_pp_control();
+	pp &= ~EDP_BLC_ENABLE;
+	io_i915_write32(pp, PCH_PP_CONTROL);
+	////POSTING_READ(PCH_PP_CONTROL);
+	mdelay(intel_dp->backlight_off_delay);
+}
+
+void ironlake_edp_pll_on(void)
+{
+	u32 dpa_ctl;
+
+	dpa_ctl = io_i915_read32(DP_A);
+	dpa_ctl |= DP_PLL_ENABLE;
+	io_i915_write32(dpa_ctl, DP_A);
+	////POSTING_READ(DP_A);
+	udelay(200);
+}
+
+static void ironlake_edp_pll_off(void)
+{
+	u32 dpa_ctl;
+
+	dpa_ctl = io_i915_read32(DP_A);
+	dpa_ctl &= ~DP_PLL_ENABLE;
+	io_i915_write32(dpa_ctl, DP_A);
+	////POSTING_READ(DP_A);
+	udelay(200);
+}
+
+/* If the sink supports it, try to set the power state appropriately */
+void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
+{
+	int ret, i;
+
+	/* Should have a valid DPCD by this point */
+	if (intel_dp->dpcd[DP_DPCD_REV] < 0x11)
+		return;
+
+	/* the convention, for whatever reason, is that mode > 0 means 'off' */
+	if (mode) {
+		ret = intel_dp_aux_native_write_1(intel_dp, DP_SET_POWER,
+						  DP_SET_POWER_D3);
+		if (ret != 1) {
+			printk(BIOS_ERR, "failed to write sink power state\n");
+		}
+	} else {
+		/*
+		 * When turning on, we need to retry for 1ms to give the sink
+		 * time to wake up.
+		 */
+		for (i = 0; i < 3; i++) {
+			ret = intel_dp_aux_native_write_1(intel_dp,
+							  DP_SET_POWER,
+							  DP_SET_POWER_D0);
+			if (ret == 1)
+				break;
+			mdelay(1);
+		}
+	}
+}
+// not sure if needed yet or not.
+void intel_dp_prepare(struct intel_dp *intel_dp);
+void intel_dp_prepare(struct intel_dp *intel_dp)
+{
+
+	ironlake_edp_backlight_off(intel_dp);
+	ironlake_edp_panel_off(intel_dp);
+
+	/* Wake up the sink first */
+	ironlake_edp_panel_vdd_on(intel_dp);
+	intel_dp_sink_dpms(intel_dp, 0);
+	intel_dp_link_down(intel_dp);
+	ironlake_edp_panel_vdd_off(intel_dp, 0);
+
+	/* Make sure the panel is off before trying to
+	 * change the mode
+	 */
+}
+
+// might be useful.
+void intel_dp_commit(struct intel_dp *intel_dp);
+void intel_dp_commit(struct intel_dp *intel_dp)
+{
+
+	ironlake_edp_panel_vdd_on(intel_dp);
+	intel_dp_sink_dpms(intel_dp, 0);
+	intel_dp_start_link_train(intel_dp);
+	ironlake_edp_panel_on(intel_dp);
+	ironlake_edp_panel_vdd_off(intel_dp, 1);
+	intel_dp_complete_link_train(intel_dp);
+	ironlake_edp_backlight_on(intel_dp);
+
+	intel_dp->dpms_mode = 0;
+}
+
+void
+intel_dp_dpms(struct intel_dp *intel_dp, int mode)
+{
+	uint32_t dp_reg = io_i915_read32(intel_dp->output_reg);
+
+	printk(BIOS_SPEW, "%s: power %s\n", __func__, mode ? "off" : "on");
+	if (mode){
+		ironlake_edp_backlight_off(intel_dp);
+		ironlake_edp_panel_off(intel_dp);
+
+		ironlake_edp_panel_vdd_on(intel_dp);
+		intel_dp_sink_dpms(intel_dp, mode);
+		intel_dp_link_down(intel_dp);
+		ironlake_edp_panel_vdd_off(intel_dp, 0);
+
+		if (is_cpu_edp(intel_dp))
+			ironlake_edp_pll_off();
+	} else {
+		if (is_cpu_edp(intel_dp))
+			ironlake_edp_pll_on();
+
+		ironlake_edp_panel_vdd_on(intel_dp);
+		intel_dp_sink_dpms(intel_dp, mode);
+		if (!(dp_reg & DP_PORT_EN)) {
+			intel_dp_start_link_train(intel_dp);
+			ironlake_edp_panel_on(intel_dp);
+			ironlake_edp_panel_vdd_off(intel_dp, 1);
+			intel_dp_complete_link_train(intel_dp);
+		} else
+			ironlake_edp_panel_vdd_off(intel_dp, 0);
+		ironlake_edp_backlight_on(intel_dp);
+	}
+	intel_dp->dpms_mode = mode;
+}
+
+/*
+ * Native read with retry for link status and receiver capability reads for
+ * cases where the sink may still be asleep.
+ */
+static int
+intel_dp_aux_native_read_retry(struct intel_dp *intel_dp, uint16_t address,
+			       uint8_t *recv, int recv_bytes)
+{
+	int ret, i;
+
+	/*
+	 * Sinks are *supposed* to come up within 1ms from an off state,
+	 * but we're also supposed to retry 3 times per the spec.
+	 */
+	for (i = 0; i < 3; i++) {
+		ret = intel_dp_aux_native_read(intel_dp, address, recv,
+					       recv_bytes);
+		if (ret == recv_bytes)
+			return ret;
+		mdelay(1);
+	}
+
+	return ret;
+}
+
+/*
+ * Fetch AUX CH registers 0x202 - 0x207 which contain
+ * link status information
+ */
+static int
+intel_dp_get_link_status(struct intel_dp *intel_dp,
+			 uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+	int ret, i;
+
+	ret = intel_dp_aux_native_read_retry(intel_dp,
+					     DP_LANE0_1_STATUS,
+					     link_status,
+					     DP_LINK_STATUS_SIZE);
+
+	printk(BIOS_SPEW, "%s:", __func__);
+	for(i = 0; i < /* !!sizeof(link_status) == 4*/
+		    DP_LINK_STATUS_SIZE; i++)
+		printk(BIOS_SPEW, " %02x", link_status[i]);
+	printk(BIOS_SPEW, "\n");
+	return ret;
+}
+
+static uint8_t
+intel_dp_link_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
+		     int r)
+{
+	return link_status[r - DP_LANE0_1_STATUS];
+}
+
+#if 0
+static uint8_t
+intel_get_adjust_request_voltage(uint8_t adjust_request[2],
+				 int lane)
+{
+	int	    s = ((lane & 1) ?
+			 DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
+			 DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
+	uint8_t l = adjust_request[lane>>1];
+
+	return ((l >> s) & 3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
+}
+
+static uint8_t
+intel_get_adjust_request_pre_emphasis(uint8_t adjust_request[2],
+				      int lane)
+{
+	int	    s = ((lane & 1) ?
+			 DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
+			 DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
+	uint8_t l = adjust_request[lane>>1];
+
+	return ((l >> s) & 3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
+}
+#endif
+const char	*voltage_names[] = {
+	"0.4V", "0.6V", "0.8V", "1.2V"
+};
+const char	*pre_emph_names[] = {
+	"0dB", "3.5dB", "6dB", "9.5dB"
+};
+const char	*link_train_names[] = {
+	"pattern 1", "pattern 2", "idle", "off"
+};
+
+/*
+ * These are source-specific values; current Intel hardware supports
+ * a maximum voltage of 800mV and a maximum pre-emphasis of 6dB
+ */
+
+static uint8_t
+intel_dp_voltage_max(struct intel_dp *intel_dp)
+{
+
+	if ((intel_dp->gen == 7) && is_cpu_edp(intel_dp))
+		return DP_TRAIN_VOLTAGE_SWING_800;
+	else if (intel_dp->has_pch_cpt && !is_cpu_edp(intel_dp))
+		return DP_TRAIN_VOLTAGE_SWING_1200;
+	else
+		return DP_TRAIN_VOLTAGE_SWING_800;
+}
+
+static uint8_t
+intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
+{
+
+	if (intel_dp->is_haswell){
+		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+		case DP_TRAIN_VOLTAGE_SWING_400:
+			return DP_TRAIN_PRE_EMPHASIS_9_5;
+		case DP_TRAIN_VOLTAGE_SWING_600:
+			return DP_TRAIN_PRE_EMPHASIS_6;
+		case DP_TRAIN_VOLTAGE_SWING_800:
+			return DP_TRAIN_PRE_EMPHASIS_3_5;
+		case DP_TRAIN_VOLTAGE_SWING_1200:
+		default:
+			return DP_TRAIN_PRE_EMPHASIS_0;
+		}
+	} else if ((intel_dp->gen == 7) && is_cpu_edp(intel_dp)) {
+		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+		case DP_TRAIN_VOLTAGE_SWING_400:
+			return DP_TRAIN_PRE_EMPHASIS_6;
+		case DP_TRAIN_VOLTAGE_SWING_600:
+		case DP_TRAIN_VOLTAGE_SWING_800:
+			return DP_TRAIN_PRE_EMPHASIS_3_5;
+		default:
+			return DP_TRAIN_PRE_EMPHASIS_0;
+		}
+	} else {
+		switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+		case DP_TRAIN_VOLTAGE_SWING_400:
+			return DP_TRAIN_PRE_EMPHASIS_6;
+		case DP_TRAIN_VOLTAGE_SWING_600:
+			return DP_TRAIN_PRE_EMPHASIS_6;
+		case DP_TRAIN_VOLTAGE_SWING_800:
+			return DP_TRAIN_PRE_EMPHASIS_3_5;
+		case DP_TRAIN_VOLTAGE_SWING_1200:
+		default:
+			return DP_TRAIN_PRE_EMPHASIS_0;
+		}
+	}
+}
+
+static void
+intel_get_adjust_train(struct intel_dp *intel_dp,
+		       uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+	uint8_t v = 0;
+	uint8_t p = 0;
+	int lane;
+	uint8_t voltage_max;
+	uint8_t preemph_max;
+
+	for (lane = 0; lane < intel_dp->lane_count; lane++) {
+		uint8_t this_v = drm_dp_get_adjust_request_voltage(
+			link_status, lane);
+		uint8_t this_p = drm_dp_get_adjust_request_pre_emphasis(
+			link_status, lane);
+
+		if (this_v > v)
+			v = this_v;
+		if (this_p > p)
+			p = this_p;
+	}
+
+	voltage_max = intel_dp_voltage_max(intel_dp);
+	if (v >= voltage_max)
+		v = voltage_max | DP_TRAIN_MAX_SWING_REACHED;
+
+	preemph_max = intel_dp_pre_emphasis_max(intel_dp, v);
+	if (p >= preemph_max)
+		p = preemph_max | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
+
+	printk(BIOS_SPEW, "%s: set to %s %s%s %s\n",
+	       __func__,
+	       voltage_names[v&3], pre_emph_names[p&3],
+	       v & DP_TRAIN_MAX_SWING_REACHED ? ",max volt swing reached":"",
+	       p & DP_TRAIN_MAX_PRE_EMPHASIS_REACHED ?
+	       ", max pre emph reached" : "");
+	for (lane = 0; lane < 4; lane++)
+		intel_dp->train_set[lane] = v | p;
+}
+
+static uint32_t
+intel_dp_signal_levels(uint8_t train_set)
+{
+	uint32_t	signal_levels = 0;
+
+	switch (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) {
+	case DP_TRAIN_VOLTAGE_SWING_400:
+	default:
+		signal_levels |= DP_VOLTAGE_0_4;
+		break;
+	case DP_TRAIN_VOLTAGE_SWING_600:
+		signal_levels |= DP_VOLTAGE_0_6;
+		break;
+	case DP_TRAIN_VOLTAGE_SWING_800:
+		signal_levels |= DP_VOLTAGE_0_8;
+		break;
+	case DP_TRAIN_VOLTAGE_SWING_1200:
+		signal_levels |= DP_VOLTAGE_1_2;
+		break;
+	}
+	switch (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) {
+	case DP_TRAIN_PRE_EMPHASIS_0:
+	default:
+		signal_levels |= DP_PRE_EMPHASIS_0;
+		break;
+	case DP_TRAIN_PRE_EMPHASIS_3_5:
+		signal_levels |= DP_PRE_EMPHASIS_3_5;
+		break;
+	case DP_TRAIN_PRE_EMPHASIS_6:
+		signal_levels |= DP_PRE_EMPHASIS_6;
+		break;
+	case DP_TRAIN_PRE_EMPHASIS_9_5:
+		signal_levels |= DP_PRE_EMPHASIS_9_5;
+		break;
+	}
+	return signal_levels;
+}
+
+/* Gen6's DP voltage swing and pre-emphasis control */
+static uint32_t
+intel_gen6_edp_signal_levels(uint8_t train_set)
+{
+	int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+					 DP_TRAIN_PRE_EMPHASIS_MASK);
+	switch (signal_levels) {
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+		return EDP_LINK_TRAIN_400_600MV_0DB_SNB_B;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return EDP_LINK_TRAIN_400MV_3_5DB_SNB_B;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
+		return EDP_LINK_TRAIN_400_600MV_6DB_SNB_B;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return EDP_LINK_TRAIN_600_800MV_3_5DB_SNB_B;
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+	case DP_TRAIN_VOLTAGE_SWING_1200 | DP_TRAIN_PRE_EMPHASIS_0:
+		return EDP_LINK_TRAIN_800_1200MV_0DB_SNB_B;
+	default:
+		printk(BIOS_ERR, "[000000.0] [drm:%s], ", __func__);
+		printk(BIOS_ERR, "Unsupported voltage swing/pre-emphasis level:"
+		       "0x%x\n", signal_levels);
+		return EDP_LINK_TRAIN_400_600MV_0DB_SNB_B;
+	}
+}
+
+/* Gen7's DP voltage swing and pre-emphasis control */
+static uint32_t
+intel_gen7_edp_signal_levels(uint8_t train_set)
+{
+	int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+					 DP_TRAIN_PRE_EMPHASIS_MASK);
+	switch (signal_levels) {
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+		return EDP_LINK_TRAIN_400MV_0DB_IVB;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return EDP_LINK_TRAIN_400MV_3_5DB_IVB;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+		return EDP_LINK_TRAIN_400MV_6DB_IVB;
+
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+		return EDP_LINK_TRAIN_600MV_0DB_IVB;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return EDP_LINK_TRAIN_600MV_3_5DB_IVB;
+
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+		return EDP_LINK_TRAIN_800MV_0DB_IVB;
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return EDP_LINK_TRAIN_800MV_3_5DB_IVB;
+
+	default:
+		printk(BIOS_ERR, "[000000.0] [drm:%s], ", __func__);
+		printk(BIOS_ERR, "Unsupported voltage swing/pre-emphasis level:"
+		       "0x%x\n", signal_levels);
+		return EDP_LINK_TRAIN_500MV_0DB_IVB;
+	}
+}
+
+/* Gen7.5's (HSW) DP voltage swing and pre-emphasis control */
+static uint32_t
+intel_dp_signal_levels_hsw(uint8_t train_set)
+{
+	int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+					 DP_TRAIN_PRE_EMPHASIS_MASK);
+	switch (signal_levels) {
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_400MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_400MV_3_5DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+		return DDI_BUF_EMP_400MV_6DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_9_5:
+		return DDI_BUF_EMP_400MV_9_5DB_HSW;
+
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_600MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_600MV_3_5DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
+		return DDI_BUF_EMP_600MV_6DB_HSW;
+
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+		return DDI_BUF_EMP_800MV_0DB_HSW;
+	case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+		return DDI_BUF_EMP_800MV_3_5DB_HSW;
+	default:
+		printk(BIOS_SPEW,
+		       "Unsupported voltage swing/pre-emphasis level:"
+		       "0x%x\n", signal_levels);
+		return DDI_BUF_EMP_400MV_0DB_HSW;
+	}
+}
+
+
+static uint8_t
+intel_get_lane_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
+		      int lane)
+{
+	int s = (lane & 1) * 4;
+	uint8_t l = link_status[lane>>1];
+
+	return (l >> s) & 0xf;
+}
+
+/* Check for clock recovery is done on all channels */
+static int
+intel_clock_recovery_ok(uint8_t link_status[DP_LINK_STATUS_SIZE],
+			int lane_count)
+{
+	int lane;
+	uint8_t lane_status;
+
+	for (lane = 0; lane < lane_count; lane++) {
+		lane_status = intel_get_lane_status(link_status, lane);
+		printk(BIOS_SPEW,
+		       "%s: Lane %d, status %02x\n", __func__,
+		       lane, lane_status);
+		if ((lane_status & DP_LANE_CR_DONE) == 0)
+			return 0;
+	}
+	return 1;
+}
+
+/* Check to see if channel eq is done on all channels */
+#define CHANNEL_EQ_BITS (DP_LANE_CR_DONE|		\
+			 DP_LANE_CHANNEL_EQ_DONE|	\
+			 DP_LANE_SYMBOL_LOCKED)
+static int
+intel_channel_eq_ok(struct intel_dp *intel_dp,
+		    uint8_t link_status[DP_LINK_STATUS_SIZE])
+{
+	uint8_t lane_align;
+	uint8_t lane_status;
+	int lane;
+
+	lane_align = intel_dp_link_status(link_status,
+					  DP_LANE_ALIGN_STATUS_UPDATED);
+	if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
+		return 0;
+	for (lane = 0; lane < intel_dp->lane_count; lane++) {
+		lane_status = intel_get_lane_status(link_status, lane);
+		if ((lane_status & CHANNEL_EQ_BITS) != CHANNEL_EQ_BITS)
+			return 0;
+	}
+	return 1;
+}
+
+static int
+intel_dp_set_link_train(struct intel_dp *intel_dp,
+			uint32_t dp_reg_value,
+			uint8_t dp_train_pat)
+{
+	int ret;
+	u32 temp;
+	int port = intel_dp->port;
+	int i;
+
+	printk(BIOS_SPEW, "%s: dp_reg_value %08lx dp_train_pat %02x\n",
+	       __func__, (unsigned long) dp_reg_value, dp_train_pat);
+	if (intel_dp->is_haswell){
+		temp = io_i915_read32(DP_TP_CTL(port));
+
+		if (dp_train_pat & DP_LINK_SCRAMBLING_DISABLE)
+			temp |= DP_TP_CTL_SCRAMBLE_DISABLE;
+		else
+			temp &= ~DP_TP_CTL_SCRAMBLE_DISABLE;
+
+		temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
+		case DP_TRAINING_PATTERN_DISABLE:
+			temp |= DP_TP_CTL_LINK_TRAIN_IDLE;
+			io_i915_write32( temp, DP_TP_CTL(port));
+
+			for(i = 0; i < 10; i++){
+				u32 status;
+				status = io_i915_read32(DP_TP_STATUS(port));
+				if (status & DP_TP_STATUS_IDLE_DONE)
+					break;
+			}
+
+			if (i == 10)
+				printk(BIOS_ERR,
+				       "Timed out waiting for DP idle patterns\n");
+
+			temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+			temp |= DP_TP_CTL_LINK_TRAIN_NORMAL;
+
+			break;
+		case DP_TRAINING_PATTERN_1:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT1;
+			break;
+		case DP_TRAINING_PATTERN_2:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT2;
+			break;
+		case DP_TRAINING_PATTERN_3:
+			temp |= DP_TP_CTL_LINK_TRAIN_PAT3;
+			break;
+		}
+		io_i915_write32( temp, DP_TP_CTL(port));
+
+	} else if (intel_dp->has_pch_cpt &&
+		   (intel_dp->gen != 7 || !is_cpu_edp(intel_dp))) {
+		dp_reg_value &= ~DP_LINK_TRAIN_MASK_CPT;
+
+		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
+		case DP_TRAINING_PATTERN_DISABLE:
+			dp_reg_value |= DP_LINK_TRAIN_OFF_CPT;
+			break;
+		case DP_TRAINING_PATTERN_1:
+			dp_reg_value |= DP_LINK_TRAIN_PAT_1_CPT;
+			break;
+		case DP_TRAINING_PATTERN_2:
+			dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
+			break;
+		case DP_TRAINING_PATTERN_3:
+			printk(BIOS_ERR,
+			       "DP training pattern 3 not supported\n");
+			dp_reg_value |= DP_LINK_TRAIN_PAT_2_CPT;
+			break;
+		}
+
+	} else {
+		dp_reg_value &= ~DP_LINK_TRAIN_MASK;
+
+		switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
+		case DP_TRAINING_PATTERN_DISABLE:
+			dp_reg_value |= DP_LINK_TRAIN_OFF;
+			break;
+		case DP_TRAINING_PATTERN_1:
+			dp_reg_value |= DP_LINK_TRAIN_PAT_1;
+			break;
+		case DP_TRAINING_PATTERN_2:
+			dp_reg_value |= DP_LINK_TRAIN_PAT_2;
+			break;
+		case DP_TRAINING_PATTERN_3:
+			printk(BIOS_ERR,"DP training pattern 3 not supported\n");
+			dp_reg_value |= DP_LINK_TRAIN_PAT_2;
+			break;
+		}
+	}
+
+	io_i915_write32( dp_reg_value, intel_dp->output_reg);
+	//POSTING_READ(intel_dp->output_reg);
+
+	intel_dp_aux_native_write_1(intel_dp,
+				    DP_TRAINING_PATTERN_SET,
+				    dp_train_pat);
+
+	if ((dp_train_pat & DP_TRAINING_PATTERN_MASK) !=
+	    DP_TRAINING_PATTERN_DISABLE) {
+		ret = intel_dp_aux_native_write(intel_dp,
+						DP_TRAINING_LANE0_SET,
+						intel_dp->train_set,
+						intel_dp->lane_count);
+		if (ret != intel_dp->lane_count){
+			printk(BIOS_ERR, "%s: wanted %d, got %d\n", __func__,
+			       intel_dp->lane_count, ret);
+			return 0;
+		}
+	}
+
+	printk(BIOS_SPEW, "%s: success\n", __func__);
+	return 1;
+}
+
+/* Enable corresponding port and start training pattern 1 */
+void
+intel_dp_start_link_train(struct intel_dp *intel_dp)
+{
+	int i;
+	uint8_t voltage;
+	int clock_recovery = 0;
+	int voltage_tries, loop_tries;
+	u32 reg;
+	uint32_t DP = intel_dp->DP;
+
+	if (intel_dp->is_haswell)
+		intel_ddi_prepare_link_retrain(intel_dp, intel_dp->port);
+
+	/* Write the link configuration data */
+	printk(BIOS_SPEW, "Write the link configuration data\n");
+	intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
+				  intel_dp->link_configuration,
+				  DP_LINK_CONFIGURATION_SIZE);
+	printk(BIOS_SPEW, "Written\n");
+
+	DP |= DP_PORT_EN;
+
+	memset(intel_dp->train_set, 0, 4);
+	voltage = 0xff;
+	voltage_tries = 0;
+	loop_tries = 0;
+	clock_recovery = 0;
+
+	for (;;) {
+		/* Use intel_dp->train_set[0] to set the voltage and pre emphasis values */
+		uint8_t	    link_status[DP_LINK_STATUS_SIZE];
+		uint32_t    signal_levels;
+
+		if (intel_dp->is_haswell){
+			signal_levels =
+				intel_dp_signal_levels_hsw(intel_dp->train_set[0]);
+			DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+			printk(BIOS_SPEW, "Haswell: levels %08x DP %08x\n", signal_levels, DP);
+		} else if ((intel_dp->gen == 7) && is_cpu_edp(intel_dp)) {
+			signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
+		} else if ((intel_dp->gen == 6) && is_cpu_edp(intel_dp)) {
+			signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
+		} else {
+			signal_levels = intel_dp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
+		}
+		printk(BIOS_ERR, "training pattern 1 signal levels %08x\n", signal_levels);
+
+		if (intel_dp->has_pch_cpt && ((intel_dp->gen == 7) || !is_cpu_edp(intel_dp)))
+			reg = DP | DP_LINK_TRAIN_PAT_1_CPT;
+		else
+			reg = DP | DP_LINK_TRAIN_PAT_1;
+
+		if (!intel_dp_set_link_train(intel_dp, reg,
+					     DP_TRAINING_PATTERN_1 |
+					     DP_LINK_SCRAMBLING_DISABLE))
+			break;
+		/* Set training pattern 1 */
+
+		udelay(100);
+		if (!intel_dp_get_link_status(intel_dp, link_status)) {
+			printk(BIOS_ERR, "failed to get link status\n");
+			break;
+		}
+
+		if (intel_clock_recovery_ok(link_status, intel_dp->lane_count)) {
+			printk(BIOS_ERR, "clock recovery OK\n");
+			clock_recovery = 1;
+			break;
+		}
+
+		/* Check to see if we've tried the max voltage */
+		for (i = 0; i < intel_dp->lane_count; i++)
+			if ((intel_dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
+				break;
+		if (i == intel_dp->lane_count) {
+			++loop_tries;
+			if (loop_tries == 5) {
+				printk(BIOS_ERR, "too many full retries, give up\n");
+				break;
+			}
+			printk(BIOS_SPEW, "%s: reset train set\n", __func__);
+			memset(intel_dp->train_set, 0, 4);
+			voltage_tries = 0;
+			continue;
+		}
+
+		/* Check to see if we've tried the same voltage 5 times */
+		if ((intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
+			++voltage_tries;
+			if (voltage_tries == 5) {
+				printk(BIOS_ERR, "too many voltage retries, give up\n");
+				break;
+			}
+		} else
+			voltage_tries = 0;
+		voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;
+		printk(BIOS_SPEW, "%s: voltage now %s\n", __func__,
+		       voltage_names[voltage]);
+
+		/* Compute new intel_dp->train_set as requested by target */
+		intel_get_adjust_train(intel_dp, link_status);
+		printk(BIOS_SPEW, "%s: new intel train set is "
+		       "%02x%02x%02x%02x",
+		       __func__,
+		       intel_dp->train_set[0], intel_dp->train_set[1],
+		       intel_dp->train_set[2], intel_dp->train_set[3]);
+	}
+
+	intel_dp->DP = DP;
+}
+
+void
+intel_dp_complete_link_train(struct intel_dp *intel_dp)
+{
+	int channel_eq = 0;
+	int tries, cr_tries;
+	uint32_t DP = intel_dp->DP;
+
+	/* channel equalization */
+	tries = 0;
+	cr_tries = 0;
+	channel_eq = 0;
+	for (;;) {
+		/* Use intel_dp->train_set[0] to set the voltage and pre emphasis values */
+		uint32_t    signal_levels;
+		uint8_t	    link_status[DP_LINK_STATUS_SIZE];
+
+		if (cr_tries > 5) {
+			printk(BIOS_ERR, "failed to train DP, aborting\n");
+			intel_dp_link_down(intel_dp);
+			break;
+		}
+
+		if (intel_dp->is_haswell) {
+			signal_levels = intel_dp_signal_levels_hsw(intel_dp->train_set[0]);
+			DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+			printk(BIOS_SPEW, "%s: new DP %08x\n", __func__,
+			       DP);
+		} else if ((intel_dp->gen == 7) && is_cpu_edp(intel_dp)) {
+			signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
+		} else if ((intel_dp->gen == 6) && is_cpu_edp(intel_dp)) {
+			signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
+		} else {
+			signal_levels = intel_dp_signal_levels(intel_dp->train_set[0]);
+			DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
+		}
+
+		/* channel eq pattern */
+		if (!intel_dp_set_link_train(intel_dp, DP,
+					     DP_TRAINING_PATTERN_2 |
+					     DP_LINK_SCRAMBLING_DISABLE))
+			break;
+
+		udelay(40000); /* was 400 */
+		if (!intel_dp_get_link_status(intel_dp, link_status))
+			break;
+
+		/* Make sure clock is still ok */
+		if (!intel_clock_recovery_ok(link_status, intel_dp->lane_count)) {
+			printk(BIOS_SPEW, "%s: Clock recovery is NOT ok"
+			       ": restarting from the start\n", __func__);
+			intel_dp_start_link_train(intel_dp);
+			cr_tries++;
+			continue;
+		}
+
+		if (intel_channel_eq_ok(intel_dp, link_status)) {
+			printk(BIOS_SPEW, "%s: success\n", __func__);
+			channel_eq = 1;
+			break;
+		}
+
+		/* Try 5 times, then try clock recovery if that fails */
+		if (tries > 5) {
+			printk(BIOS_SPEW, "%s: tries > 5,recovering. \n",
+			       __func__);
+			intel_dp_link_down(intel_dp);
+			intel_dp_start_link_train(intel_dp);
+			tries = 0;
+			cr_tries++;
+			continue;
+		}
+
+		/* Compute new intel_dp->train_set as requested by target */
+		printk(BIOS_SPEW, "%s: adjust the train\n", __func__);
+		intel_get_adjust_train(intel_dp, link_status);
+		++tries;
+	}
+
+	//io_i915_write32(reg, intel_dp->output_reg);
+	////POSTING_READ(intel_dp->output_reg);
+	intel_dp_set_link_train(intel_dp, DP, DP_TRAINING_PATTERN_DISABLE);
+}
+
+void
+intel_dp_link_down(struct intel_dp *intel_dp)
+{
+	uint32_t DP = intel_dp->DP;
+
+	if ((io_i915_read32(intel_dp->output_reg) & DP_PORT_EN) == 0)
+		return;
+
+	if (intel_dp->is_haswell){
+		printk(BIOS_SPEW, "%s: It's a haswell, skip this\n", __func__);
+		return;
+	}
+	if (is_edp(intel_dp)) {
+		DP &= ~DP_PLL_ENABLE;
+		io_i915_write32(DP, intel_dp->output_reg);
+		////POSTING_READ(intel_dp->output_reg);
+		udelay(100);
+	}
+
+	if (intel_dp->has_pch_cpt && ((intel_dp->gen == 7) || !is_cpu_edp(intel_dp))) {
+		DP &= ~DP_LINK_TRAIN_MASK_CPT;
+		io_i915_write32(DP | DP_LINK_TRAIN_PAT_IDLE_CPT, intel_dp->output_reg);
+	} else {
+		DP &= ~DP_LINK_TRAIN_MASK;
+		io_i915_write32(DP | DP_LINK_TRAIN_PAT_IDLE, intel_dp->output_reg);
+	}
+	////POSTING_READ(intel_dp->output_reg);
+
+	mdelay(17);
+
+	if (is_edp(intel_dp)) {
+		if (intel_dp->has_pch_cpt && ((intel_dp->gen == 7) || !is_cpu_edp(intel_dp)))
+			DP |= DP_LINK_TRAIN_OFF_CPT;
+		else
+			DP |= DP_LINK_TRAIN_OFF;
+	}
+
+	DP &= ~DP_AUDIO_OUTPUT_ENABLE;
+	io_i915_write32(DP & ~DP_PORT_EN, intel_dp->output_reg);
+	////POSTING_READ(intel_dp->output_reg);
+	mdelay(600000); //intel_dp->panel_power_down_delay);
+}
+
+int
+intel_dp_get_dpcd(struct intel_dp *intel_dp)
+{
+	int got = 0, want = sizeof(intel_dp->dpcd), rev;
+	got = intel_dp_aux_native_read_retry(intel_dp, 0x000, intel_dp->dpcd,
+					     want);
+	if (got < want) {
+		printk(BIOS_SPEW, "%s: got %d, wanted %d\n", __func__, got, want);
+		return 0;
+	}
+
+	rev = intel_dp->dpcd[DP_DPCD_REV];
+	if (!rev){
+		printk(BIOS_SPEW, "%s: intel->dp[DP_DPCD_REV] is 0\n",
+		       __func__);
+		return 0;
+	}
+
+	printk(BIOS_SPEW, "DPCD: %02hx%02hx%02hx%02hx%02hx%02hx%02hx%02hx\n",
+	       intel_dp->dpcd[0], intel_dp->dpcd[1], intel_dp->dpcd[2],
+	       intel_dp->dpcd[3], intel_dp->dpcd[4], intel_dp->dpcd[5],
+	       intel_dp->dpcd[6], intel_dp->dpcd[7]);
+	return 1;
+}
+
+/* I have no idea how big max downspread is. 1 byte? Hard as hell to find. */
+int
+intel_dp_get_max_downspread(struct intel_dp *intel_dp, u8 *max_downspread)
+{
+	int got, want = 1;
+	got = intel_dp_aux_native_read_retry(intel_dp, 0x000, max_downspread,
+					     want);
+	if (got < want) {
+		printk(BIOS_SPEW, "%s: got %d, wanted %d\n", __func__, got, want);
+		return 0;
+	}
+
+	printk(BIOS_SPEW, "%s: max_downspread is %02x\n", __func__, *max_downspread);
+	return 1;
+}
+