drm/i915: Populate wm.max_level for everyone

Switch ilk+ and skl+ platforms to also setting up
wm.max_level and remove a bunch of if ladders as a result.

There will be a tiny change in the debugfs on CHV machines
that have DVFS disabled in the BIOS. Presviously debugfs
would show the latency for the DVFS level as well, but
that will no longer be the case. Which is arguably better
as that number is absolutely meaningless when DVFS can't
be enabled anyway.
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230209003251.32021-1-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_display_debugfs.c

@@ -1288,14 +1288,7 @@ static void wm_latency_show(struct seq_file *m, const u16 wm[8])
 	int level;
 	int num_levels;
 
-	if (IS_CHERRYVIEW(dev_priv))
-		num_levels = 3;
-	else if (IS_VALLEYVIEW(dev_priv))
-		num_levels = 1;
-	else if (IS_G4X(dev_priv))
-		num_levels = 3;
-	else
-		num_levels = ilk_wm_max_level(dev_priv) + 1;
+	num_levels = ilk_wm_max_level(dev_priv) + 1;
 
 	drm_modeset_lock_all(&dev_priv->drm);
 
@@ -1407,14 +1400,7 @@ static ssize_t wm_latency_write(struct file *file, const char __user *ubuf,
 	int ret;
 	char tmp[32];
 
-	if (IS_CHERRYVIEW(dev_priv))
-		num_levels = 3;
-	else if (IS_VALLEYVIEW(dev_priv))
-		num_levels = 1;
-	else if (IS_G4X(dev_priv))
-		num_levels = 3;
-	else
-		num_levels = ilk_wm_max_level(dev_priv) + 1;
+	num_levels = ilk_wm_max_level(dev_priv) + 1;
 
 	if (len >= sizeof(tmp))
 		return -EINVAL;

drivers/gpu/drm/i915/display/skl_watermark.c

@@ -3258,6 +3258,11 @@ static void skl_read_wm_latency(struct drm_i915_private *i915, u16 wm[])
 
 static void skl_setup_wm_latency(struct drm_i915_private *i915)
 {
+	if (HAS_HW_SAGV_WM(i915))
+		i915->display.wm.max_level = 5;
+	else
+		i915->display.wm.max_level = 7;
+
 	if (DISPLAY_VER(i915) >= 14)
 		mtl_read_wm_latency(i915, i915->display.wm.skl_latency);
 	else

drivers/gpu/drm/i915/intel_pm.c

@@ -2836,6 +2836,8 @@ static void hsw_read_wm_latency(struct drm_i915_private *i915, u16 wm[])
 {
 	u64 sskpd;
 
+	i915->display.wm.max_level = 4;
+
 	sskpd = intel_uncore_read64(&i915->uncore, MCH_SSKPD);
 
 	wm[0] = REG_FIELD_GET64(SSKPD_NEW_WM0_MASK_HSW, sskpd);
@@ -2851,6 +2853,8 @@ static void snb_read_wm_latency(struct drm_i915_private *i915, u16 wm[])
 {
 	u32 sskpd;
 
+	i915->display.wm.max_level = 3;
+
 	sskpd = intel_uncore_read(&i915->uncore, MCH_SSKPD);
 
 	wm[0] = REG_FIELD_GET(SSKPD_WM0_MASK_SNB, sskpd);
@@ -2863,6 +2867,8 @@ static void ilk_read_wm_latency(struct drm_i915_private *i915, u16 wm[])
 {
 	u32 mltr;
 
+	i915->display.wm.max_level = 2;
+
 	mltr = intel_uncore_read(&i915->uncore, MLTR_ILK);
 
 	/* ILK primary LP0 latency is 700 ns */
@@ -2889,17 +2895,7 @@ static void intel_fixup_cur_wm_latency(struct drm_i915_private *dev_priv,
 
 int ilk_wm_max_level(const struct drm_i915_private *dev_priv)
 {
-	/* how many WM levels are we expecting */
-	if (HAS_HW_SAGV_WM(dev_priv))
-		return 5;
-	else if (DISPLAY_VER(dev_priv) >= 9)
-		return 7;
-	else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
-		return 4;
-	else if (DISPLAY_VER(dev_priv) >= 6)
-		return 3;
-	else
-		return 2;
+	return dev_priv->display.wm.max_level;
 }
 
 void intel_print_wm_latency(struct drm_i915_private *dev_priv,