drm/i915/display: Add DC5 counter and DMC debugfs entries for MTL

MTL and dgfx use the same DC5 counter.

While at it, this patch also adds the corresponding
debugfs entries. Some cleanup wrt dc3co register
which makes the code more readable.

Driver loads all firmware that it finds in the firmware
binary but platform doesn't *need* all of them. Cleaning the
previous debugs entries to reflect which firmware is needed
and if the needed firmware is loaded or not.

MTL needs both Pipe A and Pipe B DMC to be loaded
along with Main DMC.

BSpec: 49788
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221010202135.28388-1-anusha.srivatsa@intel.com

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

@@ -1065,12 +1065,13 @@ static int intel_dmc_debugfs_status_show(struct seq_file *m, void *unused)
 	seq_printf(m, "fw loaded: %s\n",
 		   str_yes_no(intel_dmc_has_payload(i915)));
 	seq_printf(m, "path: %s\n", dmc->fw_path);
-	seq_printf(m, "Pipe A fw support: %s\n",
+	seq_printf(m, "Pipe A fw needed: %s\n",
 		   str_yes_no(GRAPHICS_VER(i915) >= 12));
 	seq_printf(m, "Pipe A fw loaded: %s\n",
 		   str_yes_no(dmc->dmc_info[DMC_FW_PIPEA].payload));
-	seq_printf(m, "Pipe B fw support: %s\n",
-		   str_yes_no(IS_ALDERLAKE_P(i915)));
+	seq_printf(m, "Pipe B fw needed: %s\n",
+		   str_yes_no(IS_ALDERLAKE_P(i915) ||
+			      DISPLAY_VER(i915) >= 14));
 	seq_printf(m, "Pipe B fw loaded: %s\n",
 		   str_yes_no(dmc->dmc_info[DMC_FW_PIPEB].payload));
 
@@ -1081,22 +1082,19 @@ static int intel_dmc_debugfs_status_show(struct seq_file *m, void *unused)
 		   DMC_VERSION_MINOR(dmc->version));
 
 	if (DISPLAY_VER(i915) >= 12) {
-		if (IS_DGFX(i915)) {
+		i915_reg_t dc3co_reg;
+
+		if (IS_DGFX(i915) || DISPLAY_VER(i915) >= 14) {
+			dc3co_reg = DG1_DMC_DEBUG3;
 			dc5_reg = DG1_DMC_DEBUG_DC5_COUNT;
 		} else {
+			dc3co_reg = TGL_DMC_DEBUG3;
 			dc5_reg = TGL_DMC_DEBUG_DC5_COUNT;
 			dc6_reg = TGL_DMC_DEBUG_DC6_COUNT;
 		}
 
-		/*
-		 * NOTE: DMC_DEBUG3 is a general purpose reg.
-		 * According to B.Specs:49196 DMC f/w reuses DC5/6 counter
-		 * reg for DC3CO debugging and validation,
-		 * but TGL DMC f/w is using DMC_DEBUG3 reg for DC3CO counter.
-		 */
 		seq_printf(m, "DC3CO count: %d\n",
-			   intel_de_read(i915, IS_DGFX(i915) ?
-					 DG1_DMC_DEBUG3 : TGL_DMC_DEBUG3));
+			   intel_de_read(i915, dc3co_reg));
 	} else {
 		dc5_reg = IS_BROXTON(i915) ? BXT_DMC_DC3_DC5_COUNT :
 			SKL_DMC_DC3_DC5_COUNT;