drm/i915: initialize DDI buffer translations

DDI is introduced starting with Haswell GPU generation. So to simplify its
management in the future, we also add intel_ddi.c to hold all the
DDI-related items.

Buffer translations for DDI links must be initialized prior to enablement.
For FDI and DP, first 9 pairs of values are used to select the connection
parameters. HDMI uses the last pair of values and ignores the first 9
pairs. So we program HDMI values in both cases, which allows HDMI to work
over both FDI and DP-friendly buffers.
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/Makefile

@@ -19,6 +19,7 @@ i915-y := i915_drv.o i915_dma.o i915_irq.o \
 	  intel_crt.o \
 	  intel_lvds.o \
 	  intel_bios.o \
+	  intel_ddi.o \
 	  intel_dp.o \
 	  intel_hdmi.o \
 	  intel_sdvo.o \

drivers/gpu/drm/i915/intel_ddi.c

+/*
+ * Copyright © 2012 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:
+ *    Eugeni Dodonov <eugeni.dodonov@intel.com>
+ *
+ */
+
+#include "i915_drv.h"
+#include "intel_drv.h"
+
+/* HDMI/DVI modes ignore everything but the last 2 items. So we share
+ * them for both DP and FDI transports, allowing those ports to
+ * automatically adapt to HDMI connections as well
+ */
+static const u32 hsw_ddi_translations_dp[] = {
+	0x00FFFFFF, 0x0006000E,		/* DP parameters */
+	0x00D75FFF, 0x0005000A,
+	0x00C30FFF, 0x00040006,
+	0x80AAAFFF, 0x000B0000,
+	0x00FFFFFF, 0x0005000A,
+	0x00D75FFF, 0x000C0004,
+	0x80C30FFF, 0x000B0000,
+	0x00FFFFFF, 0x00040006,
+	0x80D75FFF, 0x000B0000,
+	0x00FFFFFF, 0x00040006		/* HDMI parameters */
+};
+
+static const u32 hsw_ddi_translations_fdi[] = {
+	0x00FFFFFF, 0x0007000E,		/* FDI parameters */
+	0x00D75FFF, 0x000F000A,
+	0x00C30FFF, 0x00060006,
+	0x00AAAFFF, 0x001E0000,
+	0x00FFFFFF, 0x000F000A,
+	0x00D75FFF, 0x00160004,
+	0x00C30FFF, 0x001E0000,
+	0x00FFFFFF, 0x00060006,
+	0x00D75FFF, 0x001E0000,
+	0x00FFFFFF, 0x00040006		/* HDMI parameters */
+};
+
+/* On Haswell, DDI port buffers must be programmed with correct values
+ * in advance. The buffer values are different for FDI and DP modes,
+ * but the HDMI/DVI fields are shared among those. So we program the DDI
+ * in either FDI or DP modes only, as HDMI connections will work with both
+ * of those
+ */
+void intel_prepare_ddi_buffers(struct drm_device *dev, enum port port, bool use_fdi_mode)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 reg;
+	int i;
+	const u32 *ddi_translations = ((use_fdi_mode) ?
+		hsw_ddi_translations_fdi :
+		hsw_ddi_translations_dp);
+
+	DRM_DEBUG_DRIVER("Initializing DDI buffers for port %c in %s mode\n",
+			port_name(port),
+			use_fdi_mode ? "FDI" : "DP");
+
+	WARN((use_fdi_mode && (port != PORT_E)),
+		"Programming port %c in FDI mode, this probably will not work.\n",
+		port_name(port));
+
+	for (i=0, reg=DDI_BUF_TRANS(port); i < ARRAY_SIZE(hsw_ddi_translations_fdi); i++) {
+		I915_WRITE(reg, ddi_translations[i]);
+		reg += 4;
+	}
+}
+
+/* Program DDI buffers translations for DP. By default, program ports A-D in DP
+ * mode and port E for FDI.
+ */
+void intel_prepare_ddi(struct drm_device *dev)
+{
+	int port;
+
+	if (IS_HASWELL(dev)) {
+		for (port = PORT_A; port < PORT_E; port++)
+			intel_prepare_ddi_buffers(dev, port, false);
+
+		/* DDI E is the suggested one to work in FDI mode, so program is as such by
+		 * default. It will have to be re-programmed in case a digital DP output
+		 * will be detected on it
+		 */
+		intel_prepare_ddi_buffers(dev, PORT_E, true);
+	}
+}

drivers/gpu/drm/i915/intel_display.c

@@ -6806,6 +6806,8 @@ void intel_modeset_init(struct drm_device *dev)
 
 	intel_init_pm(dev);
 
+	intel_prepare_ddi(dev);
+
 	intel_init_display(dev);
 
 	if (IS_GEN2(dev)) {

drivers/gpu/drm/i915/intel_drv.h

@@ -446,6 +446,7 @@ extern void intel_init_clock_gating(struct drm_device *dev);
 extern void intel_write_eld(struct drm_encoder *encoder,
 			    struct drm_display_mode *mode);
 extern void intel_cpt_verify_modeset(struct drm_device *dev, int pipe);
+extern void intel_prepare_ddi(struct drm_device *dev);
 
 /* For use by IVB LP watermark workaround in intel_sprite.c */
 extern void intel_update_watermarks(struct drm_device *dev);