drm/nouveau/dp: make functions for executing various bios tables

More code to do the same thing, but will make it easier to handle various
changes that could possibly happen the the VBIOS tables.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nouveau_dp.c

@@ -554,6 +554,49 @@ dp_link_train_eq(struct drm_device *dev, struct dp_state *dp)
 	return eq_done ? 0 : -1;
 }
 
+static void
+dp_set_downspread(struct drm_device *dev, struct dp_state *dp, bool enable)
+{
+	u16 script = 0x0000;
+	u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
+	if (table) {
+		if (table[0] >= 0x20 && table[0] <= 0x30) {
+			if (enable)
+				script = ROM16(entry[12]);
+			else
+				script = ROM16(entry[14]);
+		}
+	}
+
+	nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
+}
+
+static void
+dp_link_train_init(struct drm_device *dev, struct dp_state *dp)
+{
+	u16 script = 0x0000;
+	u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
+	if (table) {
+		if (table[0] >= 0x20 && table[0] <= 0x30)
+			script = ROM16(entry[6]);
+	}
+
+	nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
+}
+
+static void
+dp_link_train_fini(struct drm_device *dev, struct dp_state *dp)
+{
+	u16 script = 0x0000;
+	u8 *entry, *table = nouveau_dp_bios_data(dev, dp->dcb, &entry);
+	if (table) {
+		if (table[0] >= 0x20 && table[0] <= 0x30)
+			script = ROM16(entry[8]);
+	}
+
+	nouveau_bios_run_init_table(dev, script, dp->dcb, dp->crtc);
+}
+
 bool
 nouveau_dp_link_train(struct drm_encoder *encoder, u32 datarate)
 {
@@ -589,16 +632,10 @@ nouveau_dp_link_train(struct drm_encoder *encoder, u32 datarate)
 	nouveau_gpio_irq(dev, 0, nv_connector->hpd, 0xff, false);
 
 	/* enable down-spreading, if possible */
-	if (dp.table[1] >= 16) {
-		u16 script = ROM16(dp.entry[14]);
-		if (nv_encoder->dp.dpcd[3] & 1)
-			script = ROM16(dp.entry[12]);
-
-		nouveau_bios_run_init_table(dev, script, dp.dcb, dp.crtc);
-	}
+	dp_set_downspread(dev, &dp, nv_encoder->dp.dpcd[3] & 1);
 
 	/* execute pre-train script from vbios */
-	nouveau_bios_run_init_table(dev, ROM16(dp.entry[6]), dp.dcb, dp.crtc);
+	dp_link_train_init(dev, &dp);
 
 	/* start off at highest link rate supported by encoder and display */
 	while (*link_bw > nv_encoder->dp.link_bw)
@@ -632,7 +669,7 @@ nouveau_dp_link_train(struct drm_encoder *encoder, u32 datarate)
 	dp_set_training_pattern(dev, &dp, DP_TRAINING_PATTERN_DISABLE);
 
 	/* execute post-train script from vbios */
-	nouveau_bios_run_init_table(dev, ROM16(dp.entry[8]), dp.dcb, dp.crtc);
+	dp_link_train_fini(dev, &dp);
 
 	/* re-enable hotplug detect */
 	nouveau_gpio_irq(dev, 0, nv_connector->hpd, 0xff, true);