[PATCH v2 10/10] boards: enclustra-sa2: read S/N from EEPROM

[David Picard <david.picard@clermont.in2p3.fr>]

Read the SoM serial number from the EEPROM and set it in the
Barebox environment. The serial number can be checked:
- in Barebox, printenv global.serial_number
- in Linux, cat /proc/device-tree/serial-number

Signed-off-by: David Picard <david.picard@clermont.in2p3.fr>
---
 arch/arm/boards/enclustra-sa2/board.c          | 38 ++++++++++++++++++++++++++
 arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi | 12 ++++++++
 2 files changed, 50 insertions(+)

diff --git a/arch/arm/boards/enclustra-sa2/board.c b/arch/arm/boards/enclustra-sa2/board.c
index d2e539cbf9460adddc158885473f4ef0004dc284..03539132654716460cedc2a6edcaf13935dea22c 100644
--- a/arch/arm/boards/enclustra-sa2/board.c
+++ b/arch/arm/boards/enclustra-sa2/board.c
@@ -19,6 +19,7 @@
 /** Enclustra's MAC address vendor prefix is 20:B0:F7 */
 #define ENCLUSTRA_PREFIX            (0x20b0f7)
 #define MAC_ADDR_NUM_BYTES          (6)
+#define SERIAL_NUMBER_NUM_BYTES     (4)
 
 /*
  * Ethernet PHY: Microchip/Micrel KSZ9031RNX
@@ -89,6 +90,42 @@ static void set_mac_addr(void)
 	eth_register_ethaddr(1, enclustra_ethaddr_fallback2);
 }
 
+/*
+ * Read the SoM serial number via the atsha204a driver.
+ */
+static void set_ser_num(void)
+{
+	u8 *data = NULL;
+	uint32_t ser_num = 0;
+	char ser_num_str[12];
+	static const char * const aliases[] = { "som-sernum" };
+	struct device_node *np, *root;
+
+	root = of_get_root_node();
+
+	for (int i = 0; i < ARRAY_SIZE(aliases); i++) {
+		const char *alias = aliases[i];
+
+		np = of_find_node_by_alias(root, alias);
+		if (!np) {
+			pr_warn("%s() >> ERROR: can't find alias %s\n", __func__, alias);
+			continue;
+		}
+		data = nvmem_cell_get_and_read(np, "serial-number",
+									   SERIAL_NUMBER_NUM_BYTES);
+		if (IS_ERR(data)) {
+			pr_warn("%s() >> ERROR: can't read NVMEM cell\n", __func__);
+			data = NULL;
+		}
+	}
+	if (!data)
+		return;
+
+	ser_num = data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
+	sprintf(ser_num_str, "%d", ser_num);
+	barebox_set_serial_number(ser_num_str);
+}
+
 static int socfpga_init(void)
 {
 	if (!of_machine_is_compatible("enclustra,mercury-sa2"))
@@ -99,6 +136,7 @@ static int socfpga_init(void)
 								   phy_fixup);
 
 	set_mac_addr();
+	set_ser_num();
 
 #ifdef CONFIG_MACH_SOCFPGA_ENCLUSTRA_SA2_SI5338
 	/* configure clock generator on the Enclustra ST1 baseboard: */
diff --git a/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi b/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
index 78ba8008af5d60f10d6a64b0f05e97bf2381079c..ade6f4f6df3a329ee404b2b7a70fcd00c8815fdd 100644
--- a/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
+++ b/arch/arm/dts/socfpga_cyclone5_mercury_sa2.dtsi
@@ -24,6 +24,7 @@ chosen {
 
 	aliases {
 		ethernet0 = &gmac1;
+		som-sernum = "/serial-number";
 	};
 
 	/* Adjusted the i2c labels to use generic base-board dtsi files for
@@ -46,6 +47,11 @@ memory {
 		device_type = "memory";
 		reg = <0x0 0x80000000>; /* 2GB */
 	};
+
+	serial-number {
+		nvmem-cells = <&ser_num>;
+		nvmem-cell-names = "serial-number";
+	};
 };
 
 &osc1 {
@@ -82,6 +88,12 @@ nvmem-layout {
 		#address-cells = <1>;
 		#size-cells = <1>;
 
+			ser_num: serial-number@0 {
+				reg = <0x00 0x4>;
+				nvmem-cell-cells = <1>;
+				nvmem-cell-names = "serial-number";
+			};
+
 			mac_address_0: mac@10 {
 				compatible = "mac-base";
 				reg = <0x10 0x6>;

-- 
2.43.0