drm/i915/display: move dmc_firmware_path to display params

The dmc_firmware_path parameter is clearly a display parameter. Move it
there so it's available to both i915 and xe modules. This also cleans up
the ugly member in struct xe_device.

v2:
- New try with the NULL/"" param value issue resolved
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Acked-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7c8223b68fdafbc72bee0bf5afdb2ab15261cf00.1713519628.git.jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

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

@@ -27,6 +27,10 @@ static struct intel_display_params intel_display_modparams __read_mostly = {
  * debugfs mode to 0.
  */
 
+intel_display_param_named_unsafe(dmc_firmware_path, charp, 0400,
+	"DMC firmware path to use instead of the default one. "
+	"Use /dev/null to disable DMC and runtime PM.");
+
 intel_display_param_named_unsafe(vbt_firmware, charp, 0400,
 	"Load VBT from specified file under /lib/firmware");
 

drivers/gpu/drm/i915/display/intel_display_params.h

@@ -24,6 +24,7 @@ struct drm_i915_private;
  *       debugfs file
  */
 #define INTEL_DISPLAY_PARAMS_FOR_EACH(param) \
+	param(char *, dmc_firmware_path, NULL, 0400) \
 	param(char *, vbt_firmware, NULL, 0400) \
 	param(int, lvds_channel_mode, 0, 0400) \
 	param(int, panel_use_ssc, -1, 0600) \

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

@@ -75,7 +75,7 @@ static struct intel_dmc *i915_to_dmc(struct drm_i915_private *i915)
 
 static const char *dmc_firmware_param(struct drm_i915_private *i915)
 {
-	const char *p = i915->params.dmc_firmware_path;
+	const char *p = i915->display.params.dmc_firmware_path;
 
 	return p && *p ? p : NULL;
 }

drivers/gpu/drm/i915/i915_params.c

@@ -108,10 +108,6 @@ i915_param_named_unsafe(guc_firmware_path, charp, 0400,
 i915_param_named_unsafe(huc_firmware_path, charp, 0400,
 	"HuC firmware path to use instead of the default one");
 
-i915_param_named_unsafe(dmc_firmware_path, charp, 0400,
-	"DMC firmware path to use instead of the default one. "
-	"Use /dev/null to disable DMC and runtime PM.");
-
 i915_param_named_unsafe(gsc_firmware_path, charp, 0400,
 	"GSC firmware path to use instead of the default one");
 

drivers/gpu/drm/i915/i915_params.h

@@ -51,7 +51,6 @@ struct drm_printer;
 	param(int, guc_log_level, -1, 0400) \
 	param(char *, guc_firmware_path, NULL, 0400) \
 	param(char *, huc_firmware_path, NULL, 0400) \
-	param(char *, dmc_firmware_path, NULL, 0400) \
 	param(char *, gsc_firmware_path, NULL, 0400) \
 	param(bool, memtest, false, 0400) \
 	param(int, mmio_debug, -IS_ENABLED(CONFIG_DRM_I915_DEBUG_MMIO), 0600) \

drivers/gpu/drm/xe/xe_device_types.h

@@ -512,9 +512,6 @@ struct xe_device {
 		unsigned int czclk_freq;
 		unsigned int fsb_freq, mem_freq, is_ddr3;
 	};
-	struct {
-		const char *dmc_firmware_path;
-	} params;
 
 	void *pxp;
 #endif