[PATCH v3 1/4] common: Add generic function for reading serial number

[Artur Rojek]

Provide a generic way for boards to read their serial number from EEPROM
at init.

If CONFIG_ID_EEPROM is set, the new serial_read_from_eeprom() function
will now be called during the post-relocation part of the board init.

Provided is the tlv eeprom implementation of the above function, making
use of the existing, yet never utilized, populate_serial_number().
Boards which use custom logic for interaction with their EEPROMs need to
supply their own implementation.

Signed-off-by: Artur Rojek <artur at conclusive.pl>
---

v3: - restore original function name and make it static
    - provide a generic function for reading EEPROM serial number and
      wrap it around the existing tlv logic
    - move the env var check out of populate_serial_number() and into
      the new serial_read_from_eeprom() in order to stay consistent with
      the documentation

v2: - rename the function
    - move function documentation from .c file to the prototype location

 cmd/tlv_eeprom.c | 25 +++++++++----------------
 common/board_r.c |  8 ++++++++
 include/init.h   | 14 ++++++++++++++
 3 files changed, 31 insertions(+), 16 deletions(-)

diff --git a/cmd/tlv_eeprom.c b/cmd/tlv_eeprom.c
index 79796394c5c8..9aa9b070473e 100644
--- a/cmd/tlv_eeprom.c
+++ b/cmd/tlv_eeprom.c
@@ -1088,27 +1088,12 @@ int mac_read_from_eeprom(void)
 	return 0;
 }
 
-/**
- *  populate_serial_number - read the serial number from EEPROM
- *
- *  This function reads the serial number from the EEPROM and sets the
- *  appropriate environment variable.
- *
- *  The environment variable is only set if it has not been set
- *  already.  This ensures that any user-saved variables are never
- *  overwritten.
- *
- *  This function must be called after relocation.
- */
-int populate_serial_number(int devnum)
+static int populate_serial_number(int devnum)
 {
 	char serialstr[257];
 	int eeprom_index;
 	struct tlvinfo_tlv *eeprom_tlv;
 
-	if (env_get("serial#"))
-		return 0;
-
 	if (read_eeprom(devnum, eeprom)) {
 		printf("Read failed.\n");
 		return -1;
@@ -1123,3 +1108,11 @@ int populate_serial_number(int devnum)
 
 	return 0;
 }
+
+int serial_read_from_eeprom(void)
+{
+	if (env_get("serial#"))
+		return 0;
+
+	return populate_serial_number(0);
+}
diff --git a/common/board_r.c b/common/board_r.c
index 4aaa89403117..0f2cbf7bd741 100644
--- a/common/board_r.c
+++ b/common/board_r.c
@@ -121,6 +121,13 @@ __weak int fixup_cpu(void)
 	return 0;
 }
 
+#if defined(CONFIG_ID_EEPROM)
+__weak int serial_read_from_eeprom(void)
+{
+	return 0;
+}
+#endif
+
 static int initr_reloc_global_data(void)
 {
 #ifdef __ARM__
@@ -714,6 +721,7 @@ static init_fnc_t init_sequence_r[] = {
 	cpu_secondary_init_r,
 #if defined(CONFIG_ID_EEPROM)
 	mac_read_from_eeprom,
+	serial_read_from_eeprom,
 #endif
 	INIT_FUNC_WATCHDOG_RESET
 #if defined(CONFIG_PCI_INIT_R) && !defined(CONFIG_SYS_EARLY_PCI_INIT)
diff --git a/include/init.h b/include/init.h
index 3bf30476a2e0..df218c95de42 100644
--- a/include/init.h
+++ b/include/init.h
@@ -283,6 +283,20 @@ void board_init_r(struct global_data *id, ulong dest_addr)
 int cpu_init_r(void);
 int last_stage_init(void);
 int mac_read_from_eeprom(void);
+
+/**
+ *  serial_read_from_eeprom - read the serial number from EEPROM
+ *
+ *  This function reads the serial number from the EEPROM and sets the
+ *  appropriate environment variable.
+ *
+ *  The environment variable is only set if it has not been set
+ *  already. This ensures that any user-saved variables are never
+ *  overwritten.
+ *
+ *  This function must be called after relocation.
+ */
+int serial_read_from_eeprom(void);
 int set_cpu_clk_info(void);
 int update_flash_size(int flash_size);
 int arch_early_init_r(void);
-- 
2.42.0