sar: Fix semantics of `get_wifi_sar_cbfs_filename()`

Currently, if `get_wifi_sar_cbfs_filename()` returns NULL, then
`get_wifi_sar_limits()` assumes that the default filename is used for
CBFS SAR file. This prevents a board from supporting different models
using the same firmware -- some which require SAR support and some
which don't.

This change updates the logic in `get_wifi_sar_limits()` to return
early if filename is not provided by the mainboard. In order to
maintain the same logic as before, current mainboards are updated to
return WIFI_SAR_CBFS_DEFAULT_FILENAME instead of NULL in default
case.

Change-Id: I68b5bdd213767a3cd81fe41ace66540acd68e26a
Signed-off-by: Furquan Shaikh <furquan@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/51485
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/include/sar.h

@@ -41,6 +41,8 @@ struct wifi_sar_limits {
  */
 int get_wifi_sar_limits(struct wifi_sar_limits *sar_limits);
 
+#define WIFI_SAR_CBFS_DEFAULT_FILENAME	"wifi_sar_defaults.hex"
+
 const char *get_wifi_sar_cbfs_filename(void);
 
 #endif /* _SAR_H_ */

src/mainboard/google/dedede/variants/drawcia/variant.c

@@ -6,12 +6,10 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (fw_config_probe(FW_CONFIG(TABLETMODE, TABLETMODE_ENABLED)))
-		filename = "wifi_sar-drawcia.hex";
+		return "wifi_sar-drawcia.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 const char *mainboard_vbt_filename(void)

src/mainboard/google/dedede/variants/galtic/variant.c

@@ -5,9 +5,7 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (fw_config_probe(FW_CONFIG(TABLETMODE, TABLETMODE_ENABLED)))
-		filename = "wifi_sar-galtic.hex";
+		return "wifi_sar-galtic.hex";
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/dedede/variants/madoo/variant.c

@@ -5,10 +5,8 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (fw_config_probe(FW_CONFIG(TABLETMODE, TABLETMODE_ENABLED)))
-		filename = "wifi_sar-madoo.hex";
+		return "wifi_sar-madoo.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/dedede/variants/magolor/variant.c

@@ -5,10 +5,8 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (fw_config_probe(FW_CONFIG(TABLETMODE, TABLETMODE_ENABLED)))
-		filename = "wifi_sar-magolor.hex";
+		return "wifi_sar-magolor.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/hatch/variants/dratini/variant.c

@@ -7,7 +7,6 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	switch (sku_id) {
@@ -15,8 +14,7 @@ const char *get_wifi_sar_cbfs_filename(void)
 	case SKU_22_DRAGONAIR:
 	case SKU_23_DRAGONAIR:
 	case SKU_24_DRAGONAIR:
-		filename = "wifi_sar-dragonair.hex";
+		return "wifi_sar-dragonair.hex";
-		break;
 	}
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/hatch/variants/kindred/variant.c

@@ -39,12 +39,11 @@ void variant_devtree_update(void)
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	if (sku_id == 1 || sku_id == 2 || sku_id == 3 || sku_id == 4)
-		filename = "wifi_sar-kled.hex";
+		return "wifi_sar-kled.hex";
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 const char *mainboard_vbt_filename(void)

src/mainboard/google/octopus/variants/bloog/variant.c

@@ -28,7 +28,6 @@ enum {
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	switch (sku_id) {
@@ -36,18 +35,16 @@ const char *get_wifi_sar_cbfs_filename(void)
 	case SKU_34_BLOOG:
 	case SKU_35_BLOOG:
 	case SKU_36_BLOOG:
-		filename = "wifi_sar-bloog.hex";
+		return "wifi_sar-bloog.hex";
-		break;
 	case SKU_49_BLOOGUARD:
 	case SKU_50_BLOOGUARD:
 	case SKU_51_BLOOGUARD:
 	case SKU_52_BLOOGUARD:
 	case SKU_53_BIPSHIP:
 	case SKU_54_BIPSHIP:
-		filename = "wifi_sar-blooguard.hex";
+		return "wifi_sar-blooguard.hex";
-		break;
 	}
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 const char *mainboard_vbt_filename(void)

src/mainboard/google/octopus/variants/bobba/variant.c

@@ -18,13 +18,12 @@ enum {
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	if (sku_id >= 33 && sku_id <= 44)
-		filename = "wifi_sar-droid.hex";
+		return "wifi_sar-droid.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 void variant_smi_sleep(u8 slp_typ)

src/mainboard/google/octopus/variants/casta/variant.c

@@ -8,13 +8,12 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	if (sku_id == 2)
-		filename = "wifi_sar-bluebird.hex";
+		return "wifi_sar-bluebird.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 bool variant_ext_usb_status(unsigned int port_type, unsigned int port_id)

src/mainboard/google/octopus/variants/fleex/variant.c

@@ -32,12 +32,10 @@ void variant_smi_sleep(u8 slp_typ)
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (!is_lte_sku())
-		filename = "wifi_sar-fleex.hex";
+		return "wifi_sar-fleex.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 void variant_update_devtree(struct device *dev)

src/mainboard/google/octopus/variants/foob/variant.c

@@ -25,11 +25,10 @@ void variant_update_devtree(struct device *dev)
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = SKU_UNKNOWN;
 
 	sku_id = google_chromeec_get_board_sku();
 	if (sku_id == 9)
-		filename = "wifi_sar-foob360.hex";
+		return "wifi_sar-foob360.hex";
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/octopus/variants/meep/variant.c

@@ -8,7 +8,6 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id = google_chromeec_get_board_sku();
 
 	switch (sku_id) {
@@ -16,16 +15,14 @@ const char *get_wifi_sar_cbfs_filename(void)
 	case SKU_2_MEEP:
 	case SKU_3_MEEP:
 	case SKU_4_MEEP:
-		filename = "wifi_sar-meep.hex";
+		return "wifi_sar-meep.hex";
-		break;
 	case SKU_49_VORTININJA:
 	case SKU_50_VORTININJA:
 	case SKU_51_VORTININJA:
 	case SKU_52_VORTININJA:
-		filename = "wifi_sar-vortininja.hex";
+		return "wifi_sar-vortininja.hex";
-		break;
 	}
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }
 
 const char *mainboard_vbt_filename(void)

src/mainboard/google/octopus/variants/phaser/mainboard.c

@@ -6,14 +6,10 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id;
 
-	if (google_chromeec_cbi_get_sku_id(&sku_id))
+	if (google_chromeec_cbi_get_sku_id(&sku_id) || (sku_id != 5))
-		return NULL;
+		return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 
-	if (sku_id == 5)
+	return "wifi_sar-laser.hex";
-		filename = "wifi_sar-laser.hex";
-
-	return filename;
 }

src/mainboard/google/poppy/variants/rammus/mainboard.c

@@ -33,14 +33,13 @@ const char *smbios_system_sku(void)
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	uint32_t sku_id;
 
 	sku_id = variant_board_sku();
 	if (sku_id & 0x200)
-		filename = "wifi_sar-shyvana.hex";
+		return "wifi_sar-shyvana.hex";
 	else
-		filename = "wifi_sar-leona.hex";
+		return "wifi_sar-leona.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/volteer/variants/lindar/variant.c

@@ -5,12 +5,10 @@
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
-
 	if (fw_config_probe(FW_CONFIG(WIFI_SAR_ID, WIFI_SAR_ID_0)))
-		filename = "wifi_sar_0.hex";
+		return "wifi_sar_0.hex";
 	else if (fw_config_probe(FW_CONFIG(WIFI_SAR_ID, WIFI_SAR_ID_1)))
-		filename = "wifi_sar_1.hex";
+		return "wifi_sar_1.hex";
 
-	return filename;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }

src/mainboard/google/zork/variants/vilboz/variant.c

@@ -60,29 +60,23 @@ void variant_devtree_update(void)
 
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	const char *filename = NULL;
 	int sar_config;
 
 	sar_config = variant_gets_sar_config();
 
 	switch (sar_config) {
 	case 1:
-		filename = "wifi_sar-vilboz-0.hex";
+		return "wifi_sar-vilboz-0.hex";
-		break;
 	case 3:
 		/*
 		TODO: Set default first. It will be replaced after the
 		new table is generated.
 		*/
-		filename = "wifi_sar_defaults.hex";
+		return WIFI_SAR_CBFS_DEFAULT_FILENAME;
-		break;
 	case 5:
-		filename = "wifi_sar-vilboz-1.hex";
-		break;
 	case 7:
-		filename = "wifi_sar-vilboz-1.hex";
+		return "wifi_sar-vilboz-1.hex";
-		break;
+	default:
+		return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 	}
-
-	return filename;
 }

src/vendorcode/google/chromeos/sar.c

@@ -9,8 +9,6 @@
 #include <string.h>
 #include <types.h>
 
-#define WIFI_SAR_CBFS_FILENAME	"wifi_sar_defaults.hex"
-
 /*
  * Retrieve WiFi SAR limits data from CBFS and decode it
  * WiFi SAR data is expected in the format: [<WRDD><EWRD>][WGDS]
@@ -37,6 +35,12 @@ int get_wifi_sar_limits(struct wifi_sar_limits *sar_limits)
 	char *sar_str;
 	int ret = -1;
 
+	filename = get_wifi_sar_cbfs_filename();
+	if (filename == NULL) {
+		printk(BIOS_DEBUG, "Filename missing for CBFS SAR file!\n");
+		return ret;
+	}
+
 	/*
 	 * If GEO_SAR_ENABLE is not selected, SAR file does not contain
 	 * delta table settings.
@@ -64,10 +68,6 @@ int get_wifi_sar_limits(struct wifi_sar_limits *sar_limits)
 
 	printk(BIOS_DEBUG, "Checking CBFS for default SAR values\n");
 
-	filename = get_wifi_sar_cbfs_filename();
-	if (filename == NULL)
-		filename = WIFI_SAR_CBFS_FILENAME;
-
 	if (cbfs_load(filename, sar_str, sar_str_len) != sar_str_len) {
 		printk(BIOS_ERR, "%s has bad len in CBFS\n", filename);
 		goto done;
@@ -88,5 +88,5 @@ done:
 __weak
 const char *get_wifi_sar_cbfs_filename(void)
 {
-	return WIFI_SAR_CBFS_FILENAME;
+	return WIFI_SAR_CBFS_DEFAULT_FILENAME;
 }