ARM: omap-common: Add support for EEPROM

From: Lokesh Vutla <[email protected]>

Add support for EEPROM init and read. The am57xx boards have EEPROMs that have board name, version, serial data and other data. The init routine will initialize an i2c bus and then probe for the EEPROM device. The read routine will read data from the EEPROM and store it in an omap_eeprom structure. The data read will be used later in board detection of TI EVMs.

This code is in omap-common since it can be reused by other TI EVMs that have EEPROMs that use the same format. The onboard EEPROM on the Beaglebone Black, Bealgebone, AM335x EVM, AM34x GP EVM, DRA-74 EVM also follows the same format. So its better to define a common function, insted of redefining everywhere.

Signed-off-by Lokesh Vutla <[email protected]>

Signed-off-by Steve Kipisz <[email protected]>

---
 arch/arm/cpu/armv7/omap-common/Makefile      |  1 +
 arch/arm/cpu/armv7/omap-common/omap_eeprom.c | 54 +++++++++++++++++++++++++++
 arch/arm/include/asm/omap_common.h           | 55 ++++++++++++++++++++++++++++
 include/configs/am57xx_evm.h                 | 10 +++++
 4 files changed, 120 insertions(+)
 create mode 100644 arch/arm/cpu/armv7/omap-common/omap_eeprom.c

arch/arm/cpu/armv7/omap-common/Makefile +1 -0

index 464a5d1..99ea897 100644
@@ -30,3 +30,4 @@ obj-y	+= boot-common.o
 obj-y	+= lowlevel_init.o
 
 obj-y	+= mem-common.o
+obj-$(CONFIG_ENV_EEPROM_IS_ON_I2C) += omap_eeprom.o

arch/arm/cpu/armv7/omap-common/omap_eeprom.c new file +54 -0

new file mode 100644
index 0000000..98de51e
@@ -0,0 +1,54 @@
+/*
+ * omap_eeprom.c
+ *
+ * Copyright (C) 2015 Texas Instruments Incorporated -
+ * http://www.ti.com/
+ *
+ * SPDX-License-Identifier:    GPL-2.0+
+ */
+
+#include <common.h>
+#include <i2c.h>
+#include <asm/omap_common.h>
+
+int omap_eeprom_init(int i2c_bus, int dev_addr)
+{
+	int rc = 0;
+
+	rc = i2c_set_bus_num(i2c_bus);
+	if (rc) {
+		printf("I2C bus %d Initialization failed err=%d\n",
+		       i2c_bus, rc);
+		return -1;
+	}
+
+	rc = i2c_probe(dev_addr);
+	if (rc) {
+		printf("I2c probe at address %d on bus %d failed err=%d\n",
+		       dev_addr, i2c_bus, rc);
+		return -1;
+	}
+
+	return 0;
+}
+
+int omap_eeprom_read(int dev_addr, int offset, struct omap_eeprom *ep)
+{
+	int ret = 0;
+
+	ret = i2c_read(dev_addr, offset, 2, (uchar *)ep,
+		sizeof(struct omap_eeprom));
+
+	if (!ret) {
+		/*
+		 * Return error if proper header
+		 * is not found.
+		 */
+		if (ep->header != OMAP_EEPROM_HEADER)
+			ret = -1;
+	} else {
+		printf("i2c read error err=%d\n", ret);
+	}
+
+	return ret;
+}

arch/arm/include/asm/omap_common.h +24 -0

index d7b81c1..9a9b154 100644
@@ -552,6 +552,61 @@ struct vcores_data {
 	struct volts iva;
 };
 
+/*
+ * TI AM57xx EVMs define a system EEPROM that defines certain sub-fields.
+ * We use these fields to in turn see what board we are on, and what
+ * that might require us to set or not set.
+ */
+
+#define HDR_NO_OF_MAC_ADDR	3
+#define HDR_ETH_ALEN		6
+#define HDR_NAME_LEN		8
+#define OMAP_EEPROM_HEADER	0xEE3355AA
+
+/**
+ * struct omap_eeprom - This structure holds data read in from the
+ *			EEPROM.
+ * @header: This holds the magic number
+ * @name: The name of the board
+ * @version: Board revision
+ * @serail: Board serial number
+ * @config: Reserved
+ * @mac_addr: Any MAC addresses written in the EEPROM
+ *
+ * The data is this struction is read from the EEPROM on the board.
+ * It is used for board detection which is based on name. It is used
+ * to configure specific TI boards. This allows booting of multible

arch/arm/include/asm/omap_common.h +21 -0

+
+/**
+ * omap_eeprom_init - Initialize an i2c bus and probe for a device
+ * @i2c_bus: i2c bus number to initialize
+ * @dev_addr: Device address to probe for
+ *
+ * Return: 0 on success or -1 on failure.
+ */
+int omap_eeprom_init(int i2c_bus, int dev_addr);
+
+/**
+ * omap_eeprom_read - Read data from an EEPROM
+ * @dev_addr: The device address of the EEPROM
+ * @offset: Offset to start reading in the EEPROM
+ * @ep: Pointer to the omap_eeprom structure to read into
+ *
+ * Return: 0 on success, -1 if the header is invalid, or the non-zero
+ *         return code of a failed i2c_read
+ */
+int omap_eeprom_read(int dev_addr, int offset, struct omap_eeprom *ep);
+
 extern struct prcm_regs const **prcm;
 extern struct prcm_regs const omap5_es1_prcm;
 extern struct prcm_regs const omap5_es2_prcm;

include/configs/am57xx_evm.h +2 -0

index 6308cab..1b70923 100644
@@ -87,5 +87,15 @@
 #define CONFIG_SYS_SCSI_MAX_LUN		1
 #define CONFIG_SYS_SCSI_MAX_DEVICE	(CONFIG_SYS_SCSI_MAX_SCSI_ID * \
 						CONFIG_SYS_SCSI_MAX_LUN)
+/* EEPROM Support */
+#undef CONFIG_SPI