drm/i915/csr: Allow matching unknown HW steppings with generic firmware

If the firmware is generic and has a run-anywhere mode, enable it rather
than completely failing on unknown HW revisions.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Damien Lespiau <damien.lespiau@intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Cc: Sunil Kamath <sunil.kamath@intel.com>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Animesh Manna <animesh.manna@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1457352357-8433-1-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_csr.c

@@ -188,28 +188,31 @@ static const struct stepping_info bxt_stepping_info[] = {
 	{'B', '0'}, {'B', '1'}, {'B', '2'}
 };
 
-static const struct stepping_info *intel_get_stepping_info(struct drm_device *dev)
+static const struct stepping_info no_stepping_info = { '*', '*' };
+
+static const struct stepping_info *
+intel_get_stepping_info(struct drm_i915_private *dev_priv)
 {
 	const struct stepping_info *si;
 	unsigned int size;
 
-	if (IS_KABYLAKE(dev)) {
+	if (IS_KABYLAKE(dev_priv)) {
 		size = ARRAY_SIZE(kbl_stepping_info);
 		si = kbl_stepping_info;
-	} else if (IS_SKYLAKE(dev)) {
+	} else if (IS_SKYLAKE(dev_priv)) {
 		size = ARRAY_SIZE(skl_stepping_info);
 		si = skl_stepping_info;
-	} else if (IS_BROXTON(dev)) {
+	} else if (IS_BROXTON(dev_priv)) {
 		size = ARRAY_SIZE(bxt_stepping_info);
 		si = bxt_stepping_info;
 	} else {
-		return NULL;
+		size = 0;
 	}
 
-	if (INTEL_REVID(dev) < size)
-		return si + INTEL_REVID(dev);
+	if (INTEL_REVID(dev_priv) < size)
+		return si + INTEL_REVID(dev_priv);
 
-	return NULL;
+	return &no_stepping_info;
 }
 
 static void gen9_set_dc_state_debugmask(struct drm_i915_private *dev_priv)
@@ -270,13 +273,11 @@ void intel_csr_load_program(struct drm_i915_private *dev_priv)
 static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 			      const struct firmware *fw)
 {
-	struct drm_device *dev = dev_priv->dev;
 	struct intel_css_header *css_header;
 	struct intel_package_header *package_header;
 	struct intel_dmc_header *dmc_header;
 	struct intel_csr *csr = &dev_priv->csr;
-	const struct stepping_info *stepping_info = intel_get_stepping_info(dev);
-	char stepping, substepping;
+	const struct stepping_info *si = intel_get_stepping_info(dev_priv);
 	uint32_t dmc_offset = CSR_DEFAULT_FW_OFFSET, readcount = 0, nbytes;
 	uint32_t i;
 	uint32_t *dmc_payload;
@@ -284,14 +285,6 @@ static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 	if (!fw)
 		return NULL;
 
-	if (!stepping_info) {
-		DRM_ERROR("Unknown stepping info, firmware loading failed\n");
-		return NULL;
-	}
-
-	stepping = stepping_info->stepping;
-	substepping = stepping_info->substepping;
-
 	/* Extract CSS Header information*/
 	css_header = (struct intel_css_header *)fw->data;
 	if (sizeof(struct intel_css_header) !=
@@ -303,7 +296,7 @@ static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 
 	csr->version = css_header->version;
 
-	if ((IS_SKYLAKE(dev) || IS_KABYLAKE(dev)) &&
+	if ((IS_SKYLAKE(dev_priv) || IS_KABYLAKE(dev_priv)) &&
 	    csr->version < SKL_CSR_VERSION_REQUIRED) {
 		DRM_INFO("Refusing to load old Skylake DMC firmware v%u.%u,"
 			 " please upgrade to v%u.%u or later"
@@ -331,11 +324,11 @@ static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 	/* Search for dmc_offset to find firware binary. */
 	for (i = 0; i < package_header->num_entries; i++) {
 		if (package_header->fw_info[i].substepping == '*' &&
-		    stepping == package_header->fw_info[i].stepping) {
+		    si->stepping == package_header->fw_info[i].stepping) {
 			dmc_offset = package_header->fw_info[i].offset;
 			break;
-		} else if (stepping == package_header->fw_info[i].stepping &&
-			substepping == package_header->fw_info[i].substepping) {
+		} else if (si->stepping == package_header->fw_info[i].stepping &&
+			   si->substepping == package_header->fw_info[i].substepping) {
 			dmc_offset = package_header->fw_info[i].offset;
 			break;
 		} else if (package_header->fw_info[i].stepping == '*' &&
@@ -343,7 +336,8 @@ static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 			dmc_offset = package_header->fw_info[i].offset;
 	}
 	if (dmc_offset == CSR_DEFAULT_FW_OFFSET) {
-		DRM_ERROR("Firmware not supported for %c stepping\n", stepping);
+		DRM_ERROR("Firmware not supported for %c stepping\n",
+			  si->stepping);
 		return NULL;
 	}
 	readcount += dmc_offset;
@@ -389,9 +383,7 @@ static uint32_t *parse_csr_fw(struct drm_i915_private *dev_priv,
 		return NULL;
 	}
 
-	memcpy(dmc_payload, &fw->data[readcount], nbytes);
-
-	return dmc_payload;
+	return memcpy(dmc_payload, &fw->data[readcount], nbytes);
 }
 
 static void csr_load_work_fn(struct work_struct *work)