board: phytec: check eeprom_data validity

For all of the functions that access the eeprom_data, make sure these
data are valid. Use the valid member of the phytec_eeprom_data struct.
This fixes a bug where only the API revision check guarded against
accessing rubbish. But if API revision was e.g. 6, eeprom setup failed
before, but phytec_get_imx8m_eth would still happily access the data.

Fixes: dc22188cdc8 ("board: phytec: Add common PHYTEC SoM detection")

Signed-off-by: Yannic Moog <y.moog@phytec.de>
Signed-off-by: Daniel Schultz <d.schultz@phytec.de>
Reviewed-by: Teresa Remmet <t.remmet@phytec.de>
diff --git a/board/phytec/common/imx8m_som_detection.c b/board/phytec/common/imx8m_som_detection.c
index 7571076..ee34a5b 100644
--- a/board/phytec/common/imx8m_som_detection.c
+++ b/board/phytec/common/imx8m_som_detection.c
@@ -34,7 +34,7 @@
 		data = &eeprom_data;
 
 	/* We can not do the check for early API revisions */
-	if (data->payload.api_rev < PHYTEC_API_REV2)
+	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
 		return -1;
 
 	som = data->payload.data.data_api2.som_no;
@@ -75,6 +75,9 @@
 	if (!data)
 		data = &eeprom_data;
 
+	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
+		return PHYTEC_EEPROM_INVAL;
+
 	opt = phytec_get_opt(data);
 	if (opt)
 		ddr_id = PHYTEC_GET_OPTION(opt[2]);
@@ -99,7 +102,7 @@
 	if (!data)
 		data = &eeprom_data;
 
-	if (data->payload.api_rev < PHYTEC_API_REV2)
+	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
 		return PHYTEC_EEPROM_INVAL;
 
 	opt = phytec_get_opt(data);
@@ -126,7 +129,7 @@
 	if (!data)
 		data = &eeprom_data;
 
-	if (data->payload.api_rev < PHYTEC_API_REV2)
+	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
 		return PHYTEC_EEPROM_INVAL;
 
 	opt = phytec_get_opt(data);
@@ -154,7 +157,7 @@
 	if (!data)
 		data = &eeprom_data;
 
-	if (data->payload.api_rev < PHYTEC_API_REV2)
+	if (!data->valid || data->payload.api_rev < PHYTEC_API_REV2)
 		return PHYTEC_EEPROM_INVAL;
 
 	opt = phytec_get_opt(data);