ti: common: board_detect: Add function to determine if EEPROM was read

When the EEPROM is first read its contents are stored in memory as a
cache to avoid further I2C operations. To determine if the EEPROM was
previously read the easiest way is to check the memory to see if the
EEPROM's magic header value is set. Create a new function that can
determine if the EEPROM was previously read or not without having to
perform a I2C transaction.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

board/ti/common/board_detect.c

@@ -457,3 +457,13 @@ void board_ti_set_ethaddr(int index)
 		}
 	}
 }
+
+bool __maybe_unused board_ti_was_eeprom_read(void)
+{
+	struct ti_common_eeprom *ep = TI_EEPROM_DATA;
+
+	if (ep->header == TI_EEPROM_HEADER_MAGIC)
+		return true;
+	else
+		return false;
+}

board/ti/common/board_detect.h

@@ -206,6 +206,15 @@ void set_board_info_env(char *name);
 void board_ti_set_ethaddr(int index);
 
 /**
+ * board_ti_was_eeprom_read() - Check to see if the eeprom contents have been read
+ *
+ * This function is useful to determine if the eeprom has already been read and
+ * its contents have already been loaded into memory. It utiltzes the magic
+ * number that the header value is set to upon successful eeprom read.
+ */
+bool board_ti_was_eeprom_read(void);
+
+/**
  * ti_i2c_eeprom_am_set() - Setup the eeprom data with predefined values
  * @name:	Name of the board
  * @rev:	Revision of the board