drm/i915/dmc: Do not require specific versions

Currently, i915 interacts with the Hardware and not with any DMC
ABI/API, so the API is fixed within the platform, hence no need to get
this so-tied version requirement.

v2:
  - Use link to firmware guide from kernel documentation for
    "References:" instead of mailing list thread. (Rodrigo)
  - Provide a more elaborate justification in the commit message.
    (Rodrigo)

References: https://www.kernel.org/doc/html/v6.1/driver-api/firmware/firmware-usage-guidelines.htmlSigned-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221230182422.29680-2-gustavo.sousa@intel.com

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

@@ -53,51 +53,40 @@
 #define DISPLAY_VER12_DMC_MAX_FW_SIZE	ICL_DMC_MAX_FW_SIZE
 
 #define DG2_DMC_PATH			DMC_PATH(dg2, 2, 08)
-#define DG2_DMC_VERSION_REQUIRED	DMC_VERSION(2, 8)
 MODULE_FIRMWARE(DG2_DMC_PATH);
 
 #define ADLP_DMC_PATH			DMC_PATH(adlp, 2, 16)
-#define ADLP_DMC_VERSION_REQUIRED	DMC_VERSION(2, 16)
 MODULE_FIRMWARE(ADLP_DMC_PATH);
 
 #define ADLS_DMC_PATH			DMC_PATH(adls, 2, 01)
-#define ADLS_DMC_VERSION_REQUIRED	DMC_VERSION(2, 1)
 MODULE_FIRMWARE(ADLS_DMC_PATH);
 
 #define DG1_DMC_PATH			DMC_PATH(dg1, 2, 02)
-#define DG1_DMC_VERSION_REQUIRED	DMC_VERSION(2, 2)
 MODULE_FIRMWARE(DG1_DMC_PATH);
 
 #define RKL_DMC_PATH			DMC_PATH(rkl, 2, 03)
-#define RKL_DMC_VERSION_REQUIRED	DMC_VERSION(2, 3)
 MODULE_FIRMWARE(RKL_DMC_PATH);
 
 #define TGL_DMC_PATH			DMC_PATH(tgl, 2, 12)
-#define TGL_DMC_VERSION_REQUIRED	DMC_VERSION(2, 12)
 MODULE_FIRMWARE(TGL_DMC_PATH);
 
 #define ICL_DMC_PATH			DMC_PATH(icl, 1, 09)
-#define ICL_DMC_VERSION_REQUIRED	DMC_VERSION(1, 9)
 #define ICL_DMC_MAX_FW_SIZE		0x6000
 MODULE_FIRMWARE(ICL_DMC_PATH);
 
 #define GLK_DMC_PATH			DMC_PATH(glk, 1, 04)
-#define GLK_DMC_VERSION_REQUIRED	DMC_VERSION(1, 4)
 #define GLK_DMC_MAX_FW_SIZE		0x4000
 MODULE_FIRMWARE(GLK_DMC_PATH);
 
 #define KBL_DMC_PATH			DMC_PATH(kbl, 1, 04)
-#define KBL_DMC_VERSION_REQUIRED	DMC_VERSION(1, 4)
 #define KBL_DMC_MAX_FW_SIZE		BXT_DMC_MAX_FW_SIZE
 MODULE_FIRMWARE(KBL_DMC_PATH);
 
 #define SKL_DMC_PATH			DMC_PATH(skl, 1, 27)
-#define SKL_DMC_VERSION_REQUIRED	DMC_VERSION(1, 27)
 #define SKL_DMC_MAX_FW_SIZE		BXT_DMC_MAX_FW_SIZE
 MODULE_FIRMWARE(SKL_DMC_PATH);
 
 #define BXT_DMC_PATH			DMC_PATH(bxt, 1, 07)
-#define BXT_DMC_VERSION_REQUIRED	DMC_VERSION(1, 7)
 #define BXT_DMC_MAX_FW_SIZE		0x3000
 MODULE_FIRMWARE(BXT_DMC_PATH);
 
@@ -765,17 +754,6 @@ static u32 parse_dmc_fw_css(struct intel_dmc *dmc,
 		return 0;
 	}
 
-	if (dmc->required_version &&
-	    css_header->version != dmc->required_version) {
-		drm_info(&i915->drm, "Refusing to load DMC firmware v%u.%u,"
-			 " please use v%u.%u\n",
-			 DMC_VERSION_MAJOR(css_header->version),
-			 DMC_VERSION_MINOR(css_header->version),
-			 DMC_VERSION_MAJOR(dmc->required_version),
-			 DMC_VERSION_MINOR(dmc->required_version));
-		return 0;
-	}
-
 	dmc->version = css_header->version;
 
 	return sizeof(struct intel_css_header);
@@ -903,49 +881,38 @@ void intel_dmc_ucode_init(struct drm_i915_private *dev_priv)
 
 	if (IS_DG2(dev_priv)) {
 		dmc->fw_path = DG2_DMC_PATH;
-		dmc->required_version = DG2_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER13_DMC_MAX_FW_SIZE;
 	} else if (IS_ALDERLAKE_P(dev_priv)) {
 		dmc->fw_path = ADLP_DMC_PATH;
-		dmc->required_version = ADLP_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER13_DMC_MAX_FW_SIZE;
 	} else if (IS_ALDERLAKE_S(dev_priv)) {
 		dmc->fw_path = ADLS_DMC_PATH;
-		dmc->required_version = ADLS_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER12_DMC_MAX_FW_SIZE;
 	} else if (IS_DG1(dev_priv)) {
 		dmc->fw_path = DG1_DMC_PATH;
-		dmc->required_version = DG1_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER12_DMC_MAX_FW_SIZE;
 	} else if (IS_ROCKETLAKE(dev_priv)) {
 		dmc->fw_path = RKL_DMC_PATH;
-		dmc->required_version = RKL_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER12_DMC_MAX_FW_SIZE;
 	} else if (IS_TIGERLAKE(dev_priv)) {
 		dmc->fw_path = TGL_DMC_PATH;
-		dmc->required_version = TGL_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = DISPLAY_VER12_DMC_MAX_FW_SIZE;
 	} else if (DISPLAY_VER(dev_priv) == 11) {
 		dmc->fw_path = ICL_DMC_PATH;
-		dmc->required_version = ICL_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = ICL_DMC_MAX_FW_SIZE;
 	} else if (IS_GEMINILAKE(dev_priv)) {
 		dmc->fw_path = GLK_DMC_PATH;
-		dmc->required_version = GLK_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = GLK_DMC_MAX_FW_SIZE;
 	} else if (IS_KABYLAKE(dev_priv) ||
 		   IS_COFFEELAKE(dev_priv) ||
 		   IS_COMETLAKE(dev_priv)) {
 		dmc->fw_path = KBL_DMC_PATH;
-		dmc->required_version = KBL_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = KBL_DMC_MAX_FW_SIZE;
 	} else if (IS_SKYLAKE(dev_priv)) {
 		dmc->fw_path = SKL_DMC_PATH;
-		dmc->required_version = SKL_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = SKL_DMC_MAX_FW_SIZE;
 	} else if (IS_BROXTON(dev_priv)) {
 		dmc->fw_path = BXT_DMC_PATH;
-		dmc->required_version = BXT_DMC_VERSION_REQUIRED;
 		dmc->max_fw_size = BXT_DMC_MAX_FW_SIZE;
 	}
 
@@ -958,8 +925,6 @@ void intel_dmc_ucode_init(struct drm_i915_private *dev_priv)
 		}
 
 		dmc->fw_path = dev_priv->params.dmc_firmware_path;
-		/* Bypass version check for firmware override. */
-		dmc->required_version = 0;
 	}
 
 	if (!dmc->fw_path) {

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

@@ -25,7 +25,6 @@ enum {
 struct intel_dmc {
 	struct work_struct work;
 	const char *fw_path;
-	u32 required_version;
 	u32 max_fw_size; /* bytes */
 	u32 version;
 	struct dmc_fw_info {